Search PubMed⌕ Search

Biomedical subjects

M Mizutani

Publications and source records attributed to M Mizutani.

At least 55 records · Page 3Linked to original sources
PubMed2000

Adult mesoblastic nephroma with ciliated epithelium. A case report.

A case of renal pelvic tumors occurring in a 44-year-old man is reported. There were two polypoid renal pelvic tumors which consisted of glandular and stromal components. Some glands in the tumors had ciliated epithelium and were quite similar to the epididymal tubules. Other glands in the tumors resembled the collecting duct or the mesonephric remnant seen in female genitalia. Immunohistochemistry and electron microscopy revealed smooth muscle differentiation of the stromal cells of these tumors. Some psammoma bodies were seen in the glands of the tumors. We diagnosed these tumors as adult mesoblastic nephroma (MN). The patient has been followed up for 14 months, showing no evidence of recurrence. Differentiation of the tumors from angiomyolipoma, leiomyoma, and nephrogenic adenofibroma is discussed. Adult renal tumors that consist of epithelial and stromal components have been reported under various names. They constitute clinicopathologically different entities originating from pediatric MN. We suggest that these tumors should be termed "adult MN".

Adult↗
PubMed2000

Hereditary persistent right oviduct in the chicken PNP/DO line.

Hereditary, persistent, right oviduct manifested in an inbred line (PNP/DO line) from the Fayoumi breed of chickens was investigated for form of expression and mode of inheritance. Females in the PNP/DO line have varying lengths of elongated right oviducts, besides the normal left ovary, and oviducts that generally possess, irrespective of their total length, regions similar to those normally observed in a left oviduct. Observations of embryos indicated that the existence of right oviduct in this line could be attributed to the slow regression of right Müllerian duct during the embryonic stage, and left-right asymmetry in female genital system is intrinsic in this line. Intracrosses of the PNP/DO line produced 93% of female embryos with persistent right Müllerian ducts at the next generation, and reciprocal crosses of the PNP/DO line and control strains produced 5 and 30% of female embryos with persistent right Müllerian ducts in the F1 and N2 generations, respectively. Mating results suggested that this mutant trait is controlled by two pairs of autosomal recessive genes with major effects and numerous loci that have minor effects. Thus, expression of this trait is due to the interaction of major loci and the background genotype.

Animals↗
PubMed2000

Molecular cloning and characterization of ATP-phosphoribosyl transferase from Arabidopsis, a key enzyme in the histidine biosynthetic pathway.

We have characterized two isoforms of ATP-phosphoribosyl transferase (ATP-PRT) from Arabidopsis (AtATP-PRT1 [accession no. AB025251] and AtATP-PRT2), catalyzing the first step of the pathway of hisidine (His) biosynthesis. The primary structures deduced from AtATP-PRT1 and AtATP-PRT2 cDNAs share an overall amino acid identity of 74.6% and contain N-terminal chloroplast transit peptide sequences. DNA-blot analyses indicated that the ATP-PRTs in Arabidopsis are encoded by two separate genes with a closely similar gene structural organization. Both gene transcripts were detected throughout development, and protein-blot analysis revealed predominant accumulation of the AtATP-PRT proteins in Arabidopsis leaves. The His auxotrophy of a his1 mutant of Saccharomyces cerevisiae was suppressed by the transformation with AtATP-PRT1 and AtATP-PRT2 cDNAs, indicating that both isoforms are functionally active ATP-PRT enzymes. The K(m) values for ATP and phosphoribosyl pyrophosphate of the recombinant AtATP-PRT proteins were comparable to those of the native ATP-PRTs from higher plants and bacteria. It was demonstrated that the recombinant AtATP-PRTs were inhibited by L-His (50% inhibition of initial activity = 40-320 microM), suggesting that His biosynthesis was regulated in plants through feedback inhibition by L-His.

ATP Phosphoribosyltransferase↗
PubMed2000

No association of the 5' promoter region polymorphism of CYP17 with breast cancer risk in Japan.

To examine the association between breast cancer risk and a T-to-C substitution polymorphism at the 5' promoter region of CYP17, a case-control study was conducted at Aichi Cancer Center Hospital in Japan. Subjects were 144 histologically confirmed breast cancer patients diagnosed in the past 4 years and 166 hospital controls without cancer. Allele frequency among controls was 44.9% (95% confidence interval; 39.5 - 50.2) for C allele. Odds ratio (OR) of the polymorphism relative to TT-genotype was 0.97 (0.58 - 1.64) for TC-genotype and 0.81 (0.39 - 1.68) for CC-genotype. Subgroup analyses revealed that the OR was not statistically significant for the subgroups stratified by interval after diagnosis, age at menarche, age at first birth, menopausal status, body mass index, and mother / sisters' history of breast cancer. Consistent with previous studies conducted in other countries, the 5' promoter region polymorphism of CYP17 affected breast cancer risk of Japanese women to a limited extent. Although this is not a large-scale case-control study with population controls, these findings provide enough information to discourage further studies on the association between this polymorphism and breast cancer risk in Japan at large, and suggest that this polymorphism is useless for breast cancer risk estimation.

Adult↗
PubMed2000

Water stimulation of the posterior oral cavity induces inhibition of gastric motility.

The response of gastric motility to the administration of water and saline in the larynx and epiglottis was investigated in urethan-chloralose anesthetized rats. Administration of water inhibited motility of the distal stomach, but 0.15 M NaCl did not induce the inhibitory response. Bilateral sectioning of the superior laryngeal nerve (SLN) abolished the inhibitory response induced by water. Bilateral cervical vagotomies abolished the inhibitory responses, although spinal transection did not affect the inhibitory response. These inhibitory responses have been observed in immobilized animals. The degree of inhibition by water and hypotonic saline was negatively correlated with the sodium concentration. In contrast, the degree of inhibition to hypertonic saline was positively correlated with the sodium concentration. The proximal stomach also showed a reduction in intragastric pressure in response to the administration of water. These findings suggest that water-responsive afferent neurons in the SLN suppress gastric motility via the vagal efferent nerve.

Animals↗
PubMed2000

BMPs are necessary for stomach gland formation in the chicken embryo: a study using virally induced BMP-2 and Noggin expression.

Epithelial-mesenchymal interactions are necessary for the normal development of various digestive organs. In chicken proventriculus (glandular stomach), morphogenesis and differentiation of the epithelium depend upon the inductive signals coming from underlying mesenchyme. However, the nature of such signals is still unclear despite extensive analyses carried out using experimental tissue recombinations. In this study we have examined the possible involvement of bone morphogenetic proteins (BMPs) in the formation of stomach glands in the chicken embryo. Analysis of the expression patterns of BMP-2, -4 and -7 showed that these BMPs were present in the proventricular mesenchyme prior to the initiation of the proventricular gland formation. BMP-2 expression, in particular, was restricted to the proventriculus among anterior digestive organs. Virus-mediated BMP-2 overexpression resulted in an increase in the number of glands formed. Moreover, ectopic expression of Noggin, which antagonizes the effect of BMPs, in the proventricular mesenchyme or epithelium, led to the complete inhibition of gland formation, indicating that BMP signals are necessary for the proventricular gland formation. These findings suggest that BMPs are of prime importance as mesenchymal signals for inducing proventricular glands.

Animals↗
PubMed2000

Effect of aging on the incidence of digoxin toxicity.

OBJECTIVE: To evaluate the relationship of the therapeutic serum digoxin concentration (SDC) range (0.5-2 ng/mL, as recommended in previous clinical studies) with the incidence of digoxin toxicity during digoxin maintenance therapy. METHODS: Subjects included all inpatients (n = 462) and outpatients (n = 437) receiving digoxin oral maintenance therapy for heart failure and/or atrial fibrillation with tachycardia at Kosei Hospital, Anjo, Japan. SDC and blood chemistry analysis were determined, and a 24-hour Holter electrocardiographic recording was performed when the SDC was at the presumed steady-state concentration. RESULTS: Analysis of clinical data showed that there was an overlapping (toxic and nontoxic) range of SDCs in which the incidence of digoxin toxicity was patient-dependent (1.4-2.9 ng/mL). No patient exhibited signs or symptoms of digoxin toxicity when the SDC was <1.4 ng/mL; all patients had evidence of toxicity when the SDC was >3 ng/mL. Additionally, it was shown that the concentration range of this overlapping range tended to broaden and shift to lower concentrations with increasing age. Patients with signs of toxicity when their SDCs were in the overlapping range had normal serum creatinine, blood urea nitrogen, digoxin clearance, creatinine clearance, and potassium concentrations, except for a significantly higher mean age than patients without toxicity. The incidence of digoxin toxicity was dependent on increasing age in patients whose SDCs were within the recommended therapeutic range. Moreover, clinical evidence of digoxin toxicity in patients >71 years old was 26.5%, despite their SDCs falling between 1.4 and 2 ng/mL. CONCLUSIONS: Increased age is most likely associated with enhanced susceptibility to digoxin toxicity, possibly due to unknown pharmacodynamic changes. This raises the possibility that patients >71 years show clinical evidence of digoxin toxicity despite having SDCs within the recommended therapeutic range.

Age Factors↗
PubMed2000

Response of capillary cell death to aminoguanidine predicts the development of retinopathy: comparison of diabetes and galactosemia.

PURPOSE: To examine the relationship between early retinal capillary cell apoptosis and late histologic lesions of diabetic retinopathy and to compare the effects of aminoguanidine (AMG) on the retinopathies caused by diabetes and galactose feeding. METHODS: Rats with alloxan-induced diabetes and rats fed a 30% galactose diet (known to induce diabetic-like retinopathy) were assigned randomly to receive diet with (2.5 g/kg diet) or without AMG. After 6 to 8 months of diabetes or galactosemia, retinal trypsin digests were prepared, and capillary cell apoptosis was quantitated using the Tdt-mediated dUTP nick-end labeling (TUNEL) reaction in association with morphologic evidence of nuclear fragmentation. At 18 months duration, pericyte ghosts and acellular capillaries were quantitated in the isolated vasculature. Several advanced glycation end products (AGEs) were measured at 4 months of study and at 18 months of study by established methods to assess biochemical effects of AMG. RESULTS: As expected, both diabetic and galactosemic rats showed increased frequency of TUNEL-positive capillary cells at 6 to 8 months and vascular lesions characteristic of retinopathy at 18 months. AMG inhibited both the early apoptosis and late histopathology in the diabetic rats, but neither of these abnormalities in the galactosemic rats. In contrast to its preventative effect on retinopathy in the diabetic rats, AMG showed no inhibitory effect on levels of hemoglobin AGE, or tail collagen pentosidine, fluorescence, and thermal breaking time. Diabetes of 4 months' duration did not cause a detectable increase in retinal levels of several AGEs. CONCLUSIONS: The frequency of early apoptosis in retinal microvascular cells predicted the development of the histologic lesions of retinopathy in diabetes as well as in galactosemia. The beneficial effect of AMG on retinal lesions in diabetes is exerted on pathways that are either not operative or are less important in galactosemia and that may not relate to the accumulation of AGEs.

Animals↗
PubMed1999

Stabilization of Pseudomonas aeruginosa cytochrome c(551) by systematic amino acid substitutions based on the structure of thermophilic Hydrogenobacter thermophilus cytochrome c(552).

A heterologous overexpression system for mesophilic Pseudomonas aeruginosa holocytochrome c(551) (PA c(551)) was established using Escherichia coli as a host organism. Amino acid residues were systematically substituted in three regions of PA c(551) with the corresponding residues from thermophilic Hydrogenobacter thermophilus cytochrome c(552) (HT c(552)), which has similar main chain folding to PA c(551), but is more stable to heat. Thermodynamic properties of PA c(551) with one of three single mutations (Phe-7 to Ala, Phe-34 to Tyr, or Val-78 to Ile) showed that these mutants had increased thermostability compared with that of the wild-type. Ala-7 and Ile-78 may contribute to the thermostability by tighter hydrophobic packing, which is indicated by the three dimensional structure comparison of PA c(551) with HT c(552). In the Phe-34 to Tyr mutant, the hydroxyl group of the Tyr residue and the guanidyl base of Arg-47 formed a hydrogen bond, which did not exist between the corresponding residues in HT c(552). We also found that stability of mutant proteins to denaturation by guanidine hydrochloride correlated with that against the thermal denaturation. These results and others described here suggest that significant stabilization of PA c(551) can be achieved through a few amino acid substitutions determined by molecular modeling with reference to the structure of HT c(552). The higher stability of HT c(552) may in part be attributed to some of these substitutions.

Amino Acid Substitution↗
PubMed1999

Identification of Cancer Antigens in Breast Cancer by the SEREX Expression Cloning Method.

Enormous strides in cancer immunology have been made during the past decade. This is largely due to the development of methodologies capable of defining the antigenic targets on cancer cells that elicit a host immune response. The molecular cloning of antigens recognized by cytotoxic T cells by Boon and his colleagues has provided a growing list of tumor antigens, particularly for melanoma, that allows detailed monitoring of T cell responses to these antigens and offers promising targets for cancer vaccine development. An alternative new method, SEREX, for the serological identification of cancer antigens has been developed by Pfreundschuh and his colleagues. SEREX can be applied to all types of cancer including breast cancer that have been unapproachable by using cytotoxic T cells and thus offers an opportunity to define a vast range of cancer antigens. Toward thedevelopment of a vaccine for breast cancer, we have begun using SEREX to study breast cancer and have identified a few promising cancer antigens. Each antigen is now being critically evaluated as a possible vaccine target.

Journal Article↗
PubMed1999

Acute cerebellitis caused by Coxiella burnetii.

We report a childhood case of severe acute cerebellitis caused by Coxiella burnetii. After 10 days of fever and headache, the patient fell into a drowsy state. Examination of the cerebrospinal fluid (CSF) revealed pleocytosis, an increased level of protein, and negative results in bacterial and viral studies. Magnetic resonance imaging demonstrated a herniated tonsil compressed by the swollen vermis. Administration of minocycline relieved the patient's clinical symptoms. C. burnetii was isolated from the CSF obtained during convalescence.

Acute Disease↗
PubMed1999

Distal axonopathy does not occur without neurofilament accumulation in gamma-diketone neuropathy: comparative studies of normal and neurofilament-deficient quail.

The neurotoxic effects caused by chronic exposure to 2,5-hexanedione (2,5-HD) were investigated in normal and neurofilament (NF)-deficient quail (Quv strain). These quail were given 175 mg/kg per day of 2,5-HD intraperitoneally for 24 weeks. Five of nine normal quail showed clumsy gait. They had NF-rich axonal swellings in the distal parts of the peripheral nerves, ventral and lateral funiculus of the cervical cord, and cerebellar peduncles. Axonal degeneration consisting of accumulation of mitochondria, vesicles, microtubules and dense bodies was found distal to the axonal swellings. Testicular atrophy appeared in two normal quail. In contrast, four of nine Quv quail showed systemic tonic convulsion, and died of respiratory paralysis within 6 days. No significant changes in the nervous system or testis of these four dead Quv quail. The five other Quv quail survived and did not show any neurological signs. Again, no significant changes were detected in the nervous system or testis of the surviving Quv quail. The present study revealed that distal axonal degeneration did not occur without NF accumulation. These results suggest that NF accumulation is an essential factor in the development of distal axonopathy in gamma-diketone neuropathy.

Animals↗
PubMed1999

Auditory brainstem responses, electrocochleograms, and cochlear microphonics in the myelin deficient mutant hamster 'bt'.

Electrophysiological studies of the auditory pathway were performed on the mutant hamster 'bt' which is known to have myelin deficiencies in the central nervous system. Auditory brainstem responses (ABRs), electrocochleograms (EcochGs), and cochlear microphonics (CMs) were recorded. ABRs in 'bt' demonstrated markedly transformed waveforms with significantly prolonged latencies. EcochG in 'bt' showed significantly prolonged N1 latencies of the compound action potentials (CAPs) while 'bt' showed normal CMs. The myelin deficient mutant hamster 'bt' may have myelin deficiencies not only in the brainstem auditory pathway but also in the cochlear nerve.

Animals↗
PubMed1999

Evaluation of two new STR loci 9q2h2 and wg3f12 in a Japanese population.

Two short tandem repeat (STR) loci (9q2h2 and wg3f12) have been evaluated in a Japanese population. Ten and seven different alleles were observed in 9q2h2 and wg3f12 respectively. 9q2h2 displayed simple polymorphism in tetrameric repeat structure; by contrast, wg3f12 contained variable numbers of tetrameric repeats and a 30-bp deletion/insertion polymorphism. No "interalleles" were found. The expected heterozygosities of 9q2h2 and wg3fl2 were 0.749 and 0.574, respectively. No deviation from Hardy-Weinberg equilibrium was found.

Journal Article↗
PubMed1999

Evaluation of the paternity probability on an application of minisatellite variant repeat mapping using polymerase chain reaction (MVR-PCR) to paternity testing.

Minisatellite variant repeat (MVR) mapping using polymerase chain reaction (PCR) was applied to a practical case of paternity testing to evaluate the paternity probability. In order to obtain single allele mapping by allele-specific MVR-PCR, three flanking polymorphic sites for each of the MS31A and MS32 loci were investigated and all three individuals were typed as heterozygous for at least one flanking polymorphic site at each locus. Allele-specific MVR-PCR was then performed using genomic DNA. It was confirmed that one allele in the child was identical to that from the mother and the other one in the child was identical to that from the alleged father. Mapped allele codes were also compared with those in the database by dot-matrix analysis, and no identical allele was found although some motifs were shared with Japanese alleles. The paternity index and the probability of paternity exclusion in the case at these two MVR loci were calculated using the presumed values of the allele frequencies. These studies seem to illustrate the practical value of MVR mapping of MS31A and MS32 loci in paternity testing.

Journal Article↗
PubMed1999

Genetic polymorphism in the 5'-flanking region of human CYP1A2 gene: effect on the CYP1A2 inducibility in humans.

A genetic polymorphism was identified in the 5'-flanking region of human CYP1A2 gene, and its effect on the transcriptional activation of the CYP1A2 gene was investigated. Nucleotide sequence analysis revealed the existence of a point mutation from guanine (wild type) to adenine (mutated type) at position -2964 in the gene. This point mutation was detected by a polymerase chain reaction-restriction fragment length polymorphism method using DdeI or BslI restriction enzyme, and was proven to be genetically inherited. Allele frequency in 116 Japanese subjects showed 0.77 and 0.23 for the wild and mutated types of allele, respectively. The point mutation caused a significant decrease of CYP1A2 activity measured by the rate of caffeine 3-demethylation in Japanese smokers (p<0.05). Gel retardation analysis showed the existence of protein bound to the polymorphic locus. These results suggest that this polymorphism is a causal factor of decreased CYP1A2 inducibility.

Alleles↗
PubMed1999

Electron microscopic observation on the parathyroid gland of the cardiomyopathic hamster (UM-X7.1 Syrian hamster).

The ultrastructure of the parathyroid gland (PTG) of the UM-X7.1 cardiomyopathic hamster (the UM-X7.1) was qualitatively and quantitatively compared with that of the normal hamster. In the UM-X7.1, the Golgi apparatus and rER were well developed compared with those of the control hamster. Morphometric analysis revealed that the mean values of the Golgi apparatus, rER and large vacuolar bodies were significantly greater in the UM-X7.1 than in the normal hamster and the mean value of lipid droplets was significantly less in the UM-X7.1 than in the normal hamster. Ultrastructurally, we consider that in the UM-X7.1, the synthesis and release of the parathyroid hormone may be activated by an excessive amount of circulating catecholamine, and the functional activity of the PTG may be higher than that in the normal hamster.

Animals↗