Biomedical subjects

M Yamagata

Publications and source records attributed to M Yamagata.

At least 55 records · Page 3Linked to original sources

PubMed1999

Analysis of the stable levels of messenger RNA derived from different polymorphic alleles in the vitamin D receptor gene.

The association between polymorphisms in the vitamin D receptor (VDR) gene and bone mineral density (BMD) has been studied by many investigators. However, the question of how polymorphisms in the gene modulate the function of the VDR remains to be answered. To address this issue, we examined the mRNA levels of the VDR in relation to polymorphisms. First, we compared the levels of mRNA between the allele with the polymorphic TaqI-digestive site (t) and nondigestive site (T) located at exon 9 of the VDR gene determined by reverse transcription-polymerase chain reaction (RT-PCR). Total RNA was extracted from peripheral mononuclear cells in volunteers whose genotype is Tt. After the amplification of cDNA by PCR, the amplified fragments were digested by TaqI. The digested (t) and undigested (T) fragments were visualized by ethidium bromide and semiquantified by an image analyzer. In 24 subjects, the mRNA levels of allele t were significantly higher than those of allele T (1.35 fold, P < 0.001). Second, the VDR mRNA levels were estimated by competitive RT-PCR in 60 healthy subjects (35TT, 24Tt, 1 tt). The competitive template was 47 bases shorter than the product of the wild-type gene. After RT-PCR, the mRNA level was determined by a comparison with the competitive fragments. No significant difference in the mRNA level was observed between two groups (1.75 +/- 0.84 and 1.65 +/- 0.99 10(-13)mol/g total RNA in TT and Tt, respectively). In addition, no significant relationship was observed between the VDR mRNA levels and BMD in the 23 subjects whose BMD data were available. In conclusion, higher mRNA levels of allele t than T were detected, but the difference did not result in higher levels of VDR mRNA in subjects with the Tt genotype compared to those with the TT genotype.

Adult↗

PubMed1999

Washout of small stones in the bile duct by saline infusion using a side-holed balloon catheter in patients undergoing endoscopic papillary balloon dilation.

BACKGROUND: Complete bile duct clearance of stones should be achieved in patients managed with endoscopic papillary balloon dilation. However, complete retrieval of small stones or tiny fragments sometimes proves difficult using conventional devices. METHODS: We attempted the removal of fine stone fragments by saline infusion using a specially designed retrieval balloon catheter with a blind tip and a side hole located proximal to the balloon in 14 patients. RESULTS: Using this technique, bile duct clearance was achieved in a single attempt in 13 of 14 patients; 2 attempts were required in 1 patient. Cholecystitis occurred in 2 patients with gallstones in situ after the procedure. CONCLUSIONS: Saline washout using a side-holed retrieval balloon catheter effectively cleans stones and stone fragments from the bile duct in patients treated with endoscopic papillary balloon dilation.

Aged↗

PubMed1999

Formation of lamina-specific synaptic connections.

In many parts of the vertebrate central nervous system, inputs of distinct types confine their synapses to individual laminae. Such laminar specificity is a major determinant of synaptic specificity. Recent studies of several laminated structures have begun to identify some of the cells (such as guidepost neurons in hippocampus), molecules (such as N-cadherin in optic tectum, semaphorin/collapsin in spinal cord, and ephrins in cerebral cortex), and mechanisms (such as activity-dependent refinement in lateral geniculate) that combine to generate laminar specificity.

Afferent Pathways↗

PubMed1999

Gastric cancer in young patients.

BACKGROUND: Delayed diagnosis, a high rate of histologically undifferentiated types of tumors, and rapid disease progression are frequently cited as the main reasons for the poor prognosis of gastric cancer in young patients. An improved prognosis has been anticipated for young gastric cancer patients because of recent improvements in digestive tract diagnostic techniques. This retrospective study was designed to determine whether these trends have had an impact on young Japanese patients with gastric cancer, and to further elucidate differences in clinicopathologic features between elderly and young patients. METHODS: From 1984 to 1995, 1654 patients with gastric cancer were admitted to our hospital. Of these, 86 patients (5.2%) were less than 40 years of age (young group). The clinicopathologic features of this young group were reviewed retrospectively, using hospital records, and compared with those of older patients (n = 499 [29.4%], 60 to 69 years of age). RESULTS: The young group contained significantly higher percentages of female patients, epigastric pain symptoms, depressed superficial type lesions, mucosal invasion, and poorly differentiated histology; percentages of hepatic metastasis and venous invasion were lower. Survival rates for all patients and for the resected cases were significantly better in the young group (p = 0.035 and 0.017 respectively). The percentage of early stage stomach cancers for the group less than 40 years of age was 49.0% in 1984-89, but had risen to 60.9% by 1990-95. CONCLUSIONS: Early diagnosis has improved the prognosis of young gastric cancer patients. Furthermore, these data show a recent shift in stage distribution; additional prognostic improvement is anticipated for young patients with early gastric cancer.

Adult↗

PubMed1999

Up-regulated pyrimidine nucleoside phosphorylase in breast carcinoma correlates with lymph node metastasis.

BACKGROUND: The clinical significance of pyrimidine nucleoside phosphorylase (PyNPase) activity in breast carcinomas has never been determined. MATERIALS AND METHODS: In 41 cases of breast carcinoma, the enzyme activity of PyNPase was determined by the high performance liquid chromatography (HPLC) assay and its value was analyzed with clinicopathologic variables. The expression level of mRNA was examined by the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay and compared with the enzyme activity. RESULTS: The higher activity of PyNPase was significantly correlated not only with the presence of vascular permeation (P = 0.02) but of lymph node metastasis (P = 0.02). The mRNA expression correlated well with the enzyme activity (r = 0.74, P < 0.01). A multivariate analysis disclosed the PyNPase factor to be associated with lymph node metastasis. In addition, 17 (41%) showed positive staining only in the tumor stromal cells and 18 (44%) cases showed positive staining in both the tumor stromal cells and the carcinoma cells by immunohistochemical study. CONCLUSIONS: These findings suggest that PyNPase activity is a new marker predicting the malignant potential of breast carcinomas, especially with respect to lymph node metastasis, and that the RT-PCR assay is a more useful method than direct evaluation of PyNPase activity.

Adenocarcinoma↗

PubMed1999

Lack of DMBT1 expression in oesophageal, gastric and colon cancers.

Loss of sequences from human chromosome 10q has been reported in several different cancers. Recently, a second candidate tumour-suppressor gene, DMBT1, was identified in this chromosomal region. We studied the mRNA expression and homozygous deletion of this gene in human oesophageal, gastric and colon cancers. Reverse transcriptase polymerase chain reaction (RT-PCR) amplification demonstrated that 23 (53.5%) of 43 oesophageal, 5 (12.5%) of 40 gastric, and 4 (16.7%) of 24 colorectal cancer cases showed an apparent reduction in DMBT1 mRNA in tumour tissues compared with paired normal tissues. Twelve out of 15 oesophageal cancer cell lines also showed no expression. We next studied homozygous deletions within the DMBT1 gene in oesophageal cancers by using duplex PCR. Consequently, it was recognized in five (11.6%) of the primary tumours and two (13.3%) of the cell lines. These findings suggest that DMBT1 may act as a tumour-suppressor gene not only in brain tumours but also in gastrointestinal cancers, especially in oesophageal cancers.

Agglutinins↗

PubMed1999

Expression of pyrimidine nucleoside phosphorylase mRNA plays an important role in the prognosis of patients with oesophageal cancer.

To clarify the significance of the expression of pyrimidine nucleoside phosphorylase (PyNPase) mRNA as a predictive factor for the prognosis of patients with oesophageal carcinoma, the PyNPase mRNA in the tumours and normal tissues from 55 resected cases of oesophageal carcinoma was examined by a reverse transcription polymerase chain reaction (RT-PCR). As a result, a positive correlation was observed between the tumour/normal (T/N) ratio of the expression of PyNPase mRNA by RT-PCR and that of the enzyme activity of PyNPase based on the findings of an enzyme linked immunosolvent assay (r = 0.594, P = 0.009). The T/N ratio of the expression of PyNPase mRNA was significantly higher in the cases with lymph vessel invasion (P = 0.013), lymph node metastasis (P = 0.0016), and an advanced stage of the disease (P = 0.021) than those without these factors. The patients with a higher T/N ratio of PyNPase mRNA showed significantly worse prognosis than those with a lower T/N ratio (P = 0.023 with log-rank tests). A multivariate analysis for the cumulative survival rates revealed that a high T/N ratio of the expression of PyNPase mRNA was independently related to a poor prognosis. These findings suggested that the determination of PyNPase mRNA by RT-PCR thus appears to be a new useful parameter for identifying both a poor prognosis and a highly malignant potential of oesophageal carcinoma.

Adult↗

PubMed1999

Regulatory interrelations among topographic molecules CBF1, CBF2 and EphA3 in the developing chick retina.

It has been shown that topographic expression of two winged-helix transcription factors, CBF1/c-qin and CBF2, and a receptor tyrosine kinase EphA3 (Mek4/Cek4) play important roles in establishing the topographic retinotectal projection map along the rostrocaudal axis. The interrelationship among these topographic molecules in the chick retina was studied during development. The topographic expression of CBF1 and CBF2 preluded the graded expression of EphA3, but their precise expression profiles did not exactly fit together. However, interestingly, CBF1 and CBF2 were properly expressed, together with EphA3, in immortalized cell lines derived from the quail retina, which maintained position-specific characteristics. The expression of another topographic molecule SOHo-1, the sensory organ homeobox-1 transcription factor, was separate from EphA3 expression. Ectopic expression of CBF1 using in ovo electroporation repressed the expression of CBF2, and misexpression of CBF2 influenced the graded localization of EphA3 in the retina, albeit imperfectly. Taken together, it is suggested that retinal cells first begin to express CBF1 or CBF2 according to their topographic positions, generate cellular descendants in which the expression of CBF1 and CBF2 is maintained cell-autonomously, and then establish the nasotemporal gradient of EphA3 under the control of CBF2, although indirect.

Alkaline Phosphatase↗

PubMed1999

Specific expression of ezrin, a cytoskeletal-membrane linker protein, in a subset of chick retinotectal and sensory projections.

Lamina-specific neuronal connections are a fundamental feature in many parts of the vertebrate central nervous system. In the chick, the optic tectum is the primary visual centre, and it has a multilaminated structure consisting of 15 laminae, of which only three or four receive retinal projections. Each of the retinorecipient laminae establishes synaptic connections selectively from one of a few subsets of retinal ganglion cells (RGCs). We have generated a series of monoclonal antibodies that appear to stain only one of the retinorecipient laminae. One of these, TB4, stained lamina F which receives inputs from a subpopulation of approximately 10-20% of RGCs which express the presynaptic acetylcholine receptor beta2-subunit. TB4 recognized a single 79-kDa protein on immunoblotting. cDNA cloning and immunochemical analysis revealed that the TB4 antigen molecule was ezrin, a cytoskeletal-membrane linker molecule belonging to the ezrin-radixin-moesin family. Unilateral enucleation of the eye, both prior to and after the establishment of retinotectal projections, attenuated the lamina-selective staining with TB4 in the contralateral tectum, suggesting that ezrin is anterogradely transported from RGCs to lamina F. Ezrin was thus expressed in a subset of RGCs that project to lamina F. Similar subset-selective expression and resultant lamina-selective distribution of ezrin were also observed in the lamina-specific central projections from the dorsal root ganglia. The staining pattern with TB4 in the dorsal root ganglia and spinal cord indicated that high expression of ezrin was restricted in cutaneous sensory neurons, but not in muscle sensory neurons. Since ezrin modulates cell morphology and cell adhesion profiles by linking membrane proteins with the cytoskeleton, it was suggested that ezrin is involved in the formation and/or maintenance of lamina-specific connections for neuronal subpopulations in the visual and somatosensory systems.

Amino Acid Sequence↗

PubMed1999

High proportion of mutant K-ras gene in pancreatic juice of patients with pancreatic cystic lesions.

BACKGROUND/AIMS: It was recently reported that the quantitative analysis of mutant K-ras gene in pancreatic juice could be useful for the diagnosis of pancreatic cancer. This methodology was applied to patients with pancreatic cystic lesions. METHODS: DNA was extracted from pancreatic juice collected at the time of endoscopy with injection of secretin. The ratio of the K-ras mutant allele to the wild-type allele was measured by two methods to detect and semiquantify mutant K-ras gene: polymerase chain reaction/preferential homoduplex formation assay and enriched polymerase chain reaction/enzyme linked mini-sequence assay. RESULTS: A high frequency of K-ras mutation was detected (more than 2% of all K-ras genes) in six of 14 patients (43%) with pancreatic cysts. This frequency was similar to those detected in patients with pancreatic adenocarcinoma and in intraductal papillary neoplasms of the pancreas. In contrast, the frequency of mutation was low (less than 2%) in patients without either pancreatic cysts or pancreatic neoplasms. CONCLUSIONS: K-ras gene mutation may be derived from duct cells in the pancreas with a high potential for tumorigenesis. Therefore careful follow up of patients with a pancreatic cyst is recommended if they are found to have a high level of the mutant gene in the pancreatic juice.

Adenocarcinoma↗

PubMed1999

[The present and future of the pulmonary function tests. The relationship between respiratory and non-respiratory function].

Pulmonary function is classified as respiratory and non-respiratory function. Respiratory pulmonary function involves exchange of O2 and CO2 gas at alveolar units in the lung and non-respiratory pulmonary function concerns metabolism of enzymes, hormones, surfactants vaso-active substances and immunological factors in the lung. The purpose of this study was to examine the relationship between respiratory and non-respiratory function using our newly developed expired NO gas continuous analytic method and the calculation method of ventilatory energy of the lung. Furthermore, we analyzed the relationship between arterial blood O2 pressure (PaO2) and mitochondrial function.

Humans↗

PubMed1999

[Expired nitric oxide concentration derived from nasal cavity and that derived from airway and lung in Japanese cedar pollinosis].

AIM: Japanese cedar pollinosis (Type I allergy to Japanese cedar pollen) shows a high incidence in spring in Japan, demonstrating symptoms such as pituita, rhinostenosis, lacrimation and sometimes pharyngeal pain. The following study investigated whether expired nitric oxide (NO) concentration is increased in Japanese cedar pollinosis, and whether expired NO concentration can be used to discriminate from cold syndrome which symptoms are similar to Japanese cedar pollinosis. SUBJECTS AND METHODS: In 20 healthy subjects, 20 patients with Japanese cedar pollinosis and 20 patients with cold syndrome, expired NO concentrations derived from nasal cavity and those derived from airway and lung were measured. Expired NO concentrations derived from nasal cavity and those derived from airway and lung were compared among the groups. RESULTS: In patients with Japanese cedar pollinosis expired NO concentrations derived from nasal cavity and those derived from airway and lung markedly increased. In patients with cold syndrome there were no significant increases in these concentrations. DISCUSSION: It is considered that expired NO concentration is useful for discriminating Japanese cedar pollinosis from cold syndrome. It seems interesting that not only expired NO concentrations derived from nasal cavity but also those derived from airway and lung were clevated. Generalized airway inflammation may be present, even without clinical asthma, in patients with Japanese cedar pollinosis.

Adult↗

PubMed1998

The winged-helix transcription factor CWH-3 is expressed in developing neural crest cells.

Neural crest cells are a migratory population that finally give rise to peripheral neurons and numerous other differentiated cell types. We report here that chicken winged-helix 3 (CWH-3), a winged-helix transcription factor, is specifically expressed in the early premigratory and migrating neural crest cells at all axial levels in chick embryos. CWH-3-positive cells first appeared in the neural plate at the early primitive-streak stage when commitment to the neural crest cell fate occurs, and the expression declined after they arrived at their final destinations. These observations suggested that CWH-3 is a determinant for neural crest differentiation at the most dorsal part of the neural tube, reminiscent of HNF-3beta, another winged-helix factor, which determines the ventral part of the neural tube.

Animals↗

PubMed1998

Characterization of the activation function-2 domain of the human 1,25-dihydroxyvitamin D3 receptor.

In this study, we determined the ligand-dependent activation function domain 2 (AF-2) of the human vitamin D receptor (hVDR) and characterized it using site-directed mutagenesis. A single mutation at glutamic acid-420 (E420Q) and an additional mutation at leucine-417 (L417A-E420Q) eliminated ligand-dependent transcriptional activation. In addition, lysine-264 was also demonstrated to be vital for ligand-induced transactivation. However, bacterial-overexpressed transcriptional factor IIB (TFIIB) was able to bind to both AF-2 and lysine-264 mutant hVDRs in vitro. The ligand-dependent transactivation via wild type hVDR was interfered with weakly only when a 10-fold molar excess of L417A-E420Q plasmid was co-transfected. This suppressive effect was diminished by introducing an additional mutation at a cysteine residue in the DNA binding domain. Thus, we conclude that the AF-2 domain of the hVDR located between amino acids 417 and 420, as well as lysine-264, are essential for ligand-dependent transactivation, and that TFIIB was not necessary for the function of these two regions of the hVDR. Our finding that AF-2 mutant hVDRs exhibit only very weak suppressive effect may indicate a difference in the molecular mechanism of the VDR-mediated transactivation from other nuclear receptors.

Animals↗

PubMed1998

Lumbar spinal canal stenosis associated with progressive degenerative changes of the spine. A case report.

STUDY DESIGN: Case report. OBJECTIVES: To report a case of spinal canal stenosis associated with progressive degenerative changes of the lumbar spine. SUMMARY OF BACKGROUND DATA: As far as the authors are aware, there has been no similar case reported. METHODS: The clinical features of the case are reported, and the pathology is discussed. RESULTS: In a 40-year-old man, spinal canal stenosis developed, associated with progressive degenerative changes of the lumbar spine. The man underwent posterior decompression and fusion using pedicle screws. The surgical results were satisfactory at the time of writing this report. CONCLUSIONS: This case presented a peculiar clinical course, which could not be categorized under previously reported disorders. It may be a new disease entity of spinal canal stenosis. The surgical outcome was satisfactory 2 years, 6 months after surgery.

Adult↗

PubMed1998

Familial amyloid polyneuropathy related to transthyretin mutation Val30 to Leu in a Japanese family.

A rare variant transthyretin that has a leucine-for-valine substitution at position 30 was reported in a sporadic case of type 1 familial amyloid polyneuropathy (FAP). We found the same substitution in members of a Japanese family with FAP. Three individuals in this family had a guanine-to-cytosine mutation at the first base of codon 30 in exon 2. This family shows a direct link between a valine-to-leucine substitution at position 30 and type 1 FAP.

Amino Acid Substitution↗

PubMed1998

New remote-controlled growing-rod spinal instrumentation possibly applicable for scoliosis in young children.

Progressive scoliosis in young children has been treated with "spinal instrumentation without fusion" to avoid interference with spinal growth. Patients have to undergo a series of operations to have instruments exchanged for maintaining the correction. We have developed a newly designed remote-controlled growing-rod spinal instrumentation system proposed for the treatment of progressive scoliosis in young children. It can be used to stretch and correct the spinal deformities repeatedly and non-surgically, by means of a remote controller, after the first instrumentation operation. The purpose of this study is to describe the possible clinical application of this system for the treatment of progressive scoliosis in young children. To this end, we used the system in five beagle dogs with induced scoliotic deformities. The maximum distraction force of the instrument was 194 N. Correction of 1 cm was performed non-surgically in awake animals 3 weeks after the instrumentation operation, and then correction of 1 cm was carried out again 6, 9, and 12 weeks after the operation. The average initial Cobb's angle of the induced scoliotic deformities was 25 degrees; this was corrected to 20 degrees, 15 degrees, 8 degrees, and 3 degrees, after the distractions at 3, 6, 9, and 12 weeks, respectively, postoperatively. All corrections were performed non-surgically without apparent complications. By repetitive distractions with the use of our new system, we may be able to reduce the number of operations required in young scoliotic children.

Animals↗

PubMed1998

Direct repeat 3-type element lacking the ability to bind to the vitamin D receptor enhances the function of a vitamin D-responsive element.

In a previous study, we identified the element which allows the maximum response to 1,25(OH)2D3 in concert with two vitamin D-responsive elements (VDREs) in the rat 25-hydroxyvitamin D3 24-hydroxylase gene promoter, and designated it an accessory element [Ohyama, Y., Ozono, K., Uchida, M., Yoshimura, M., Shinki, T., Suda, T. and Yamamoto, O. Functional assessment of two vitamin D-responsive elements in the rat 25-hydroxyvitamin D3 24-hydroxylase gene. J. Biol. Chem., 1996, 271, 30381-30385]. The accessory element located adjacent to the proximal VDRE is not capable of binding to the vitamin D receptor (VDR), while its nucleotide sequence resembles the consensus sequence of VDREs, direct repeat 3 (DR3). To clarify the difference between the accessory element and VDREs, the function of the accessory element was compared with that of VDREs. The mutated accessory elements with a single nucleotide substitution showed the capability of binding to the VDR in vitro. However, these mutants still did not act as a VDRE when driven by the heterologous SV40 promoter. The accessory element did not enhance the function of a cAMP-responsive element. The corresponding site of the accessory element in the human 24-hydroxylase is a DR4-type element, and this element did not function as an accessory element. These results indicate that a critical nucleotide sequence is necessary for the binding to the VDR and for mediating the vitamin D effect, and suggest the different regulation between the rat and human 24-hydroxylase gene.

8-Bromo Cyclic Adenosine Monophosphate↗