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Biomedical subjects

R Ito

Publications and source records attributed to R Ito.

At least 91 records · Page 5Linked to original sources
PubMed1995

Morphological differences in the skull of ascorbic acid-deficient ODS rats.

The physiological importance of ascorbic acid (AsA) in bone formation has been thought to be due mainly to its effects on collagen production and, consequently, matrix formation. However, effects of AsA deficiency on growing animals are poorly understood. The purpose of this experiment was to find how AsA deficiency affects craniofacial growth cephalometrically, and the periodontal ligament and the bone density of alveolar septum histologically. Five-week-old growing male rats with hereditary defects in AsA synthesis (ODS rats) placed on an AsA-deficient or minimally supplemented diet for 4 weeks showed a marked reduction in plasma AsA level and a negative or slight increment in body weight. Cephalometric evaluation revealed that craniofacial growth was influenced by AsA deficiency. Histological observations of periodontal structure and bone density in AsA-deficient animals showed no difference from controls, whereas the periodontal ligament of the upper first molar in the deficient animals was narrower than that of controls. These observations indicate that AsA deficiency reduces craniofacial size and the width of the periodontal ligament significantly in growing rats, whereas bone density is not affected. Thus, AsA, through collagen production, may be important to the increase in size of the craniofacial structures in growing animals.

Alveolar Bone Loss↗
PubMed1995

Correlation between argyrophilic nucleolar organizer region (AgNOR) counts and histologic grades with respect to biologic behavior of salivary adenoid cystic carcinoma.

The quantification of argyrophilic nucleolar organizer regions (AgNOR) was performed in 34 cases of adenoid cystic carcinoma (ACC) to determine (1) whether AgNOR count correlates with its different histologic grades pertinent to prognosis, and (2) whether AgNOR counts can offer any additional prognostic advantage over histologic grading. According to Szanto et al.'s histologic grading criteria (4), 12 cases were Grade 1, 7 cases Grade 2, and 15 were Grade 3. Patients were divided into 20 favorable cases (without metastases) and 14 unfavorable cases (with metastases). Although most Grade 3 tumors had high AgNOR counts (> or = 4) and Grade 1 tumors with low (< 4) AgNOR counts outnumbered those with high AgNOR counts, considerable overlap of AgNOR values in different grades was observed. However, all unfavorable cases had high AgNOR counts regardless of their histologic grades, suggesting that the metabolic alterations associated with the malignancy level of ACC may partly be portrayed by the AgNOR count, irrespective of the histologic appearance. Cumulative survival rates of Grade 1 tumors and of tumors with low AgNOR counts were better than those of Grade 3 tumors and those with high AgNOR counts. Within the limited number of cases in this series the AgNOR count exhibits a potential for identifying some aggressive ACCs that cannot be detected by histology alone.

Adult↗
PubMed1995

[Measurement of anti-acetylcholine receptor antibody using human rhabdomyosarcoma cell line].

We developed a radioimmunoassay for AChR Ab using AChR solubilized from membrane extracts of human rhabdomyosarcoma cell line (RD cell). The binding affinity of this AChR to the alpha-Bungarotoxin (alpha-BTX) was similar to that of AChR from cell surface. Lyophilized AChR was stable within two months at -20 degrees C. In our assay system, sera from patients with Myasthenia Gravis (MG) showed markedly high titers and frequency (94%) of anti-AChR Ab. On the other hand, almost all sera from normal and non-myasthenic patients such as rheumatoid arthritis and thyroid disease were negative (< 0.2nmol/l). Our assay using AChR from RD cells shows sufficient results in the intra- and inter-CV values, and recovery and dilution tests. AChR Ab titers of our assay showed good correlations with those measured by AChRs from both human ischemic muscles and TE671 cells (commercial kit). The radioimmunoassay for AChR Ab using the membrane extracts of RD cells has high sensitivity, specificity and stability. Therefore, the assay is valuable as the routine assay for the diagnosis of MG.

Autoantibodies↗
PubMed1994

Expression of CD44 abnormal transcripts in human gastric carcinomas.

Twenty gastric carcinoma cases were studied for the detection of CD44 aberrant transcripts using a cDNA/PCR/blot-hybridization technique which can detect splice variants containing an aberrant exon 11 of the CD44 gene. All the tumor tissues as well as their metastatic foci demonstrated overexpression of CD44 splice variants of more than 1.0 kbp than corresponding normal gastric mucosas. Six out of nine (66.7%) well-differentiated or intestinal type gastric cancers overexpressed more than three aberrant transcripts, whereas ten out of eleven (90.9%) poorly differentiated or diffuse type cancers overexpressed single or two lower molecular weight variants. These results indicate that the detection of CD44 transcription variants can serve as a powerful tool for the diagnosis of gastric cancer. It is also suggested from the difference in variant expression pattern that well-differentiated type and poorly differentiated type gastric carcinomas have different genetic pathways.

Adult↗
PubMed1994

High-intensity proton and T2-weighted MRI signals in the globus pallidus in juvenile-type of dentatorubral and pallidoluysian atrophy.

Dentatorubral and pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder. An expanded CAG trinucleotide repeat sequence motif in a gene on the short arm of chromosome 12 has recently been identified in patients with DRPLA. Juvenile-type DRPLA is characterized by childhood onset and progressive myoclonic epilepsy (PME). According to the pathological study, the degeneration of the globus pallidus is more marked in this than in other types. We observed high-intensity signals in the globus pallidus on proton and T2-weighted magnetic resonance imaging (MRI) in a patient clinically diagnosed as juvenile-type DRPLA who had the expanded CAG trinucleotide repeat motif in the DRPLA gene. The globus pallidus may be affected in the early stages of this type of DRPLA, and MRI may be useful for the early diagnosis of DRPLA.

Atrophy↗
PubMed1993

Interleukin 1 alpha acts as an autocrine growth stimulator for human gastric carcinoma cells.

The expression and effect of interleukin 1 alpha (IL-1 alpha) were examined in human gastric carcinoma cell lines to determine if IL-1 alpha acts as a growth stimulator for these cells. Six of 8 gastric carcinoma cell lines expressed IL-1 alpha mRNA at various levels. Among them, TMK-1 and MKN-7 cells secreted IL-1 alpha into the culture fluid, in an especially large amount by MKN-7 cells. Scatchard plot analysis of IL-1 alpha binding revealed that TMK-1 cells had only one type of high-affinity receptors, whereas MKN-7 cells had high- and low-affinity receptors. Cell growth and DNA synthesis of TMK-1 and MKN-7 cells were stimulated by IL-1 alpha, and those of MKN-7 were inhibited by addition of anti-IL-1 alpha antibody or IL-1 receptor antagonist. The expression of IL-1 alpha mRNA by these cell lines was induced by either IL-1 alpha, epidermal growth factor, or transforming growth factor alpha. On the other hand, IL-1 alpha increased the mRNA expression for transforming growth factor alpha and epidermal growth factor receptor. These findings indicate that IL-1 alpha is an autocrine growth stimulator for gastric carcinoma cells and the interaction with epidermal growth factor/transforming growth factor alpha/receptor system should be involved in the growth modulation by IL-1 alpha.

Cell Division↗
PubMed1993

Expression of Bombyx mori cytoplasmic polyhedrosis virus polyhedrin in insect cells by using a baculovirus expression vector, and its assembly into polyhedra.

A cDNA encoding the cytoplasmic polyhedrin of Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) strain H was introduced into an improved baculovirus expression vector which can be utilized to express foreign genes in the Spodoptera frugiperda cell line IPLB-SF-21AE (Sf21 cells) and the B. mori cell line BmN. A recombinant virus produced large, cubic inclusion body-like structures in infected Sf21 and BmN cells. Western blot analysis showed that these structures were BmCPV polyhedra. This result suggested that the supramolecular assembly of BmCPV polyhedrin is responsible for its properties.

Animals↗
PubMed1993

Sequence analysis of low-molecular-weight RNAs by the use of non-radioactive labeling.

A new procedure for non-radioactive labeling of the 3'-terminal -OH was developed to facilitate the sequencing works on low-molecular-weight RNAs. At first, biotinylated pCp (cytidine 3',5'-bisphosphate) was synthesized and ligated to the 3'-terminal of yeast tRNA(Phe) with the aid of RNA ligase. Although the labeling efficiency was high enough, this labeling resulted in a lack of the sequence ladders around the 3'-terminal 10 nucleotides. A longer oligonucleotide, p(dC)(dT)16-Biotin was designed to overcome this defect and proved to be a better non-radioactive 3'-labeling probe.

Biotin↗
PubMed1991

Novel muteins of human tumor necrosis factor alpha.

For chemical synthesis of a gene coding for human tumor necrosis factor alpha (TNF-alpha), DNA sequence predicted by the amino acid sequence of human TNF molecule was prepared. Codons were chosen according to the codon usage in Escherichia coli (E. coli). The 490 bp gene was assembled by enzymic ligation of 42 oligonucleotides and was cloned into a vector (pKK223-3) for high expression of active TNF-alpha in E. coli. With use of site-directed mutagenesis on this DNA, five different muteins of TNF-alpha were synthesized. TNF-M1 and TNF-M4 have deletions of His-73 and Gln-102, respectively. These deletions didn't cause loss of the cytotoxic activity against L929 cells. TNF-M5, which has a substitution of Asp-10 to Arg, had the similar cytotoxic activity to that of TNF-alpha. The cytotoxic spectra against several tumor cells were not changed by this substitution. TNF-M3 has an amino acid substitution of Glu-116 to His which occupies this position in human TNF-beta. This substitution didn't change the cytotoxicity. In addition, evidence was presented that the change of the carboxyl terminal residue doesn't always influence the cytotoxic activity of TNF-alpha. Many different muteins were also isolated by random mutagenesis with hydroxylamine-HCl. One of the muteins, which carries a mutation of His-15 to Tyr, lost the cytotoxic activity almost completely.

Amino Acid Sequence↗
PubMed1991

Immunohistochemical study of tyrosine-hydroxylase-positive cells and fibers in the chicken spinal cord.

Tyrosine hydroxylase (TH)-positive cells and fibers were examined by immunohistochemistry in the chick spinal cord. TH-positive cells, which were located in laminae I, V and X, were most frequently found in the rostral part of the cervical spinal cord, with fewer cells being found in more caudal levels of the spinal cord. TH-positive cells located in lamina X, which were bipolar in shape, were mainly found in regions lateral as well as just ventral to the central canal. They had processes reaching to the central canal. The terminals of these cerebrospinal-fluid-contacting cells were oval in shape, and were most frequently found at the ventral wall of the central canal. There were dense clusters of TH-positive fibers in lamina X. A meshwork-like structure of TH-positive fibers was found over the lateral wall of the central canal. A high density of TH-positive fibers was also found in the medial part of laminae V-VII. In lamina IX, small numbers of TH-positive fibers were observed in the lateral motor column of the brachial spinal cord, and in the medial and lateral motor columns of the lumbosacral spinal cord. However, within the medial motor column of the brachial spinal cord TH-positive fibers were densely distributed around somal as well as dendritic profiles. Similar to our previous observations on serotoninergic fibers. TH-positive fibers were also differentially distributed in the ventral horn of the chicken spinal cord: a high density of TH-positive fibers was localized to specific regions of the spinal motor nucleus.

Animals↗