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Biomedical subjects

T Momoi

Publications and source records attributed to T Momoi.

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

[An analytical study on recognition confusion of vowels in patients with 22 channel cochlear implant].

Vowel confusion was studied in 16 postlingually deaf patients with 22 multi-channel cochlear implants. Tests for vowel perception were performed on these patients after a 3 month training period, using/a,e,i,o,u/pronounced by a speech therapist. Analyses were conducted on the relationship between the vowel confusion matrix and the frequencies of the 1st and 2nd formants of vowels used in this study, and the relationship between the confusion matrix and the numbers in order of the activating electrodes. The results revealed that the higher percentages of errors in vowel recognition were as follows: /o/-->/a/ (12%),/o/-->/u/ (13%), and/e/-->/i/ (8%), possibly due to small differences found in the F1 and F2 frequency ratio or in the F2 frequency of the vowels, which results in a similar distance between two electrodes, pairs or similar stimulated places in the sense of the high frequency part of the cochlea.

Adult↗
PubMed1995

The effects of hemodialysis (HD) membranes on interleukin 1-beta (IL-1 beta) production from peripheral blood mononuclear cells (PBMC).

Dialysis-related symptoms are thought to be mediated by monocyte/macrophage-derived inflammatory cytokines, including interleukin 1-beta (IL-1 beta) and tumor necrosis factor alpha (TNF alpha). We investigated the effect of hemodialysis (HD) membranes on IL-1 beta production using cultured peripheral blood mononuclear cells (PBMC). PBMC were stimulated with lipopolysaccharide (LPS) and the cell content and production of IL-1 beta were measured by ELISA. PBMC from a single healthy donor incubated with 5% of untreated plasma, and we found that HD patients plasma enhanced IL-1 beta production less than normal control plasma. The plasma obtained from the venous side of HD patients 15 minutes after starting a single HD (15-min HD plasma) did not enhance IL-1 beta production as much as the plasma from the arterial side, either before or upon completion of a single HD (pre-HD plasma, post-HD plasma). We studied IL-1 beta productivity when pre-HD plasma (arterial side) and 15-min HD plasma (venous side) were added to autologous PBMC. The IL-1 beta production by PBMC was less when the 15-min HD plasma was added to PBMC as compared to when the pre-HD plasma was added. This reduction tended to be greater when a dialyzer membrane used was a large-pore type made of regenerated cellulose (RC) or polymethylmetacrylate (PMMA) than with a small-pore RC membrane. After HD for 2 weeks using a small-pore RC membrane, the same HD patient was then treated with a large-pore RC membrane. The PBMC IL-1 beta production level decreased with the use of the large-pore RC as compared to the case with the small-pore RC membranes. The present study suggests that large-pore dialyzer membranes remove middle molecules and low molecular weight proteins which enhance IL-1 beta production, and that this production may be regulated by some mechanism unrelated to complement activation.

Biocompatible Materials↗
PubMed1994

Changes of the expression and distribution of retinoic acid receptors during neurogenesis in mouse embryos.

The expression and distribution of three retinoic acid receptors, alpha, beta, and gamma, were investigated in the CNS of mouse embryos during development. mRNAs and protein of RAR-beta that were expressed in the spinal cord of the 12.5-day mouse embryo decreased during development but they were not decreased in the brain. The RAR-beta-positive cells were already present in the ventral region of the spinal cord of 10.5-day mouse embryos, gradually appeared in the dorsal region during development and then disappeared from the spinal cord after birth. In the brain, RAR-beta-positive cells were detected in the mesencephalon and rhombencephalon but not in the telencephalon of the 12.5-day mouse embryos. RAR-beta-positive cells were present in the hippocampus and cingulum but not in the neocortex of 14.5-day mouse embryos. Most neurons in the hippocampus of 16.5-day mouse embryos and the cortex of newborn mice were RAR-beta-positive. In the spinal cord, RAR-alpha mRNAs and proteins also decreased during development but more gradually than RAR-beta mRNAs and proteins. During development, the distributions of RAR-alpha and -beta in the spinal cord and brain did not differ substantially. The main difference was the appearance of a subtypes of RAR-alpha, a 52-kDa protein, in the brain of newborn mice. On the other hand, RAR-gamma proteins were only faintly detected in the spinal cord and the brain of the mice during the embryonal stages but these increased after birth. The distribution of RAR-alpha- or -beta-positive cells were consistent with the neurogenesis during development in the spinal cord and brain.

Amino Acid Sequence↗
PubMed1993

Protein-losing gastroenteropathy with facial anomaly and growth retardation: a mild case of Hennekam syndrome.

A 7-year-old boy with a peculiar face, protein-losing gastroenteropathy and growth retardation is reported. Although he has a face similar to those 5 cases reported previously by Hennekam et al. (Am J Med Genet 34:593-600, 1989) and Gabrielli et al. (Am J Med Genet 40:244-247, 1991), he is not mentally retarded nor does he have severe lymphedema. This patient seems to have a mild case of the Hennekam syndrome.

Albumins↗
PubMed1993

Acquired growth hormone deficiency due to pituitary stalk transection after head trauma in childhood.

Two patients are reported with growth hormone deficiency due to head trauma in childhood. Although their injuries were outwardly only slight and there was no loss of consciousness and no subsequent neurological deficits, they exhibited gradual growth retardation from the time of the trauma. Provocative endocrinological tests showed growth hormone deficiency and MRI showed transection of the pituitary stalk. These findings suggest that ordinary head trauma, as well as perinatal insult and congenital abnormalities, could be a cause of growth hormone deficiency.

Child↗
PubMed1993

[Clinical study on S-1108 in treatment of pediatric infections].

To evaluate the efficacy, the safety and the usefulness of a novel and esterified cephem antibiotic for oral use, S-1108, in pediatric infections, a clinical trial was performed. The study subjects were 15 patients including 9 with acute pharyngitis, 1 with acute tonsillitis, 2 with acute bronchitis, 1 with chronic pyelonephritis, 1 with acute abscess of the skin and 1 with impetigo contagiosa. S-1108 was administered orally at a dose of 3.7 mg/kg to 12.5 mg/kg t.i.d. for 4 to 9 days. Clinical effects were excellent in 7 cases, good in 6, fair in 1 and poor in 1. The Overall efficacy rate was 86.7%. Bacteriologically, causative organisms were all eradicated in evaluable 4 cases. As to side effects, diarrhea was observed in 2 cases. No abnormal laboratory test values were obtained.

Adolescent↗
PubMed1992

Retinoic acid ambivalently regulates the expression of MyoD1 in the myogenic cells in the limb buds of the early developmental stages.

The expression of MyoD1 in myogenic cells located in the muscle prospective region of the limb bud at stage 20-22 was highly sensitive to retinoic acid. Unlike RAR-beta, the expression of MyoD1 mRNA in the muscle precursor cells was significantly increased by retinoic acid at lower concentrations (0.1-10 nM), but inhibited by it at higher concentrations (0.1-1 microM). The ambivalent modulation of MyoD1 expression suggested that MyoD1 expression is regulated by not only the retinoic acid receptor and its response element, but also by other factors. Retinoic acid may be involved in the differentiation of the myogenic cells during early development.

Animals↗
PubMed1992

Cellular retinoic acid binding protein type II was preferentially localized in medium and posterior parts of the progress zone of the chick limb bud.

The expression and distribution of cellular retinoic acid binding protein II (CRABP II) was examined in chick limb buds. CRABP II was detected in the limb buds at Hamburger and Hamilton (1) stage 21 and the amount of CRABP II was gradually increased during stages 21-27 and thereafter decreased. CRABP II was mainly located in the progress zone, and the dorsal and ventral premuscular mass in the proximal region of the limb buds at stage 23. CRABP II was preferentially localized in the medium and posterior parts rather than the anterior part of the progress zone; The content of CRABP II in the medium and posterior parts was 8-9 times more than that in the anterior part.

Animals↗
PubMed1992

Activin synergistically increased c-jun mRNA in P19 embryonal carcinoma cells in the presence of retinoic acid.

Activin and retinoids, which are involved in the induction and regulation of the early differentiation process in vertebrate embryogenesis, synergistically increased the amount of c-jun mRNA in P19 embryonal carcinoma cells, but activin alone had no effect. Among the retinoids, all-trans-retinoic acid most effectively increased c-jun mRNA. Activin (lng/ml) was sufficient to induce the synergistic increase of c-jun mRNA in P19 EC cells with all-trans-retinoic acid. The synergistic increase of the amount of c-jun mRNA by their cooperative action may be important in vertebrate development.

Activins↗
PubMed1992

Glycogen storage disease type III with muscle involvement: reappraisal of phenotypic variability and prognosis.

A review of the case histories of 19 Japanese patients with enzymatically proven glycogen storage disease (GSD) III who developed muscular symptoms at various ages illustrates the phenotypic variability of this disease. There seem to be 4 subgroups of GSD III with muscle involvement according to the clinical symptoms. The first group of patients is characterized by the childhood onset of muscle weakness and hepatic disorders. The second group of patients develops muscular symptoms in adult years while the liver symptoms start in childhood. The third group includes the patients whose muscle weakness started in adult years long after liver symptoms in childhood had disappeared. The fourth group shows only muscular symptoms as adults without any sign or history of liver dysfunction since childhood. The prognosis for each subgroup seems to be different; however, none of them appears to be better than that for GSD I, as has been suggested previously.

Female↗
PubMed1992

Short stature with normal growth hormone and elevated IGF-I.

We report on a Japanese girl with short stature, malar hypoplasia, up-slanting palpebral fissures, blue sclerae and thin, stiff and slightly brownish hair. Short stature started in utero and her psychomotor development was normal. Menarche appeared at 13 years 8 months. Height at 14 years 5 months was 132 cm (-4.6 SD). Her growth hormone (GH) sleep pattern and responses to insulin, L-dopa, arginine, propranolol-glucagon and growth hormone-releasing hormone were normal. Plasma insulin-like growth factor I (IGF-I) was high (2170-4860 units/l) and increased from 4860 to 7080 units/l 20 h after biosynthetic GH injection. Gel infiltration patterns of the free and protein-bound IGF-I in plasma from the patient were not different from the controls; IGF-I fraction of the high and low molecular weight binding protein and the non-protein bound fraction were 75.5%, 15.8% and 8.7%, respectively. IGF-I from the patient showed normal bioactivities when determined by [35S]sulphate and [3H]thymidine uptake into cultured rat chondrocytes, and by [3H]thymidine and [3H]alpha-aminoisobutyric acid uptake into the patient's skin fibroblasts. IGF-I binding to cultured skin fibroblasts from the patient was comparable to that of controls. These results suggest that tissue specific defects of IGF-I receptors may be the cause of increased IGF-I levels in the patient.

Animals↗
PubMed1992

Pyridoxine-dependent seizures: report of a case with atypical clinical features and abnormal MRI scans.

A Japanese girl with atypical pyridoxine-dependent seizures is reported. Until 9 months of age the seizures had been controlled by conventional anticonvulsants. The initial administration of pyridoxine was followed by a collapse; the suppression-burst pattern changed to an almost flat pattern in the EEG. T1- and T2-weighted magnetic resonance imaging (MRI) scans showed poor differentiation between white and gray matter, and T2-weighted MRI scans showed periventricular hyperintensity areas adjacent to the posterior horns of lateral ventricles. The findings in this patient indicate that pyridoxine should be given to infants with intractable epilepsy, regardless of the response to anticonvulsants, and that resuscitation facilities should be available during such a trial.

Brain↗
PubMed1991

Changes in the ganglioside composition of human neuroblastoma cells under different growth conditions.

The ganglioside composition of human neuroblastoma cells (LA-N-1 and LA-N-5) was studied in samples obtained from (1) original cells in tissue cultures, (2) tumors grown in nude mice inoculated with original cells and (3) cells in tissue cultures re-established from the mouse tumors. The amounts of "a" pathway gangliosides (GM2, GM1 and GD1a) and those of the "b" pathway (GD3, GD2, GD1b and GT1b) differed according to the culture conditions. The "b" pathway gangliosides were markedly increased in the tumors grown in nude mice. In contrast, the "a" pathway gangliosides were abundant in cultures of both original and re-established cells. We also measured the enzymatic activities of UDP-N-acetylgalactosamine: GM3, N-acetylgalactosaminyl transferase (EC 2.4.1.92) and of CMP-N-acetylneuraminic acid: GM3 sialyl transferase (EC 2.4.99.8) in neuroblastoma cells cultured under these conditions. These enzymes are thought to be the key enzymes involved in the synthesis of the "a" and "b" pathway gangliosides. Though there was no significant difference in the activity of N-acetylgalactosaminyl transferase between original cells and tumors in nude mice, re-established cells showed a definitely higher activity (3.5 times higher than in the original cells). On the other hand, tumors grown in nude mice had a markedly higher activity of sialyl transferase than that of original cells or re-established cells. These findings suggest that the culture conditions and/or the type of cell growth play some role in the synthesis and expression of gangliosides in neuroblastoma cells.

Animals↗
PubMed1990

A point mutation in the mitochondrial tRNA(Leu)(UUR) gene in MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes).

Mitochondrial myopathy, encephalopathy, lactic acidosis and strokelike episode (MELAS) is a major group of heterogeneous mitochondrial disorders. To identify the defective gene, mitochondrial DNA from a patient with MELAS was sequenced by using amplified DNA fragments as sequencing templates. In 14.1 kbp determined out of 16.6 kbp of the whole mitochondrial gene, at least 21 nucleotides were different from those of a control human mitochondrial DNA. One of the substitutions was a transition of A to G in the tRNA(Leu) (UUR) gene at Cambridge nucleotide number 3,243. This nucleotide is conserved not only in many mitochondrial tRNAs but in most cytosolic tRNA molecules. An Apa I restriction site was gained by the substitution of this nucleotide. The Apa I digestion of the amplified DNA fragment revealed that all independent 6 patients had G at nucleotide number 3,243 in their mitochondrial DNAs, but none of 11 control individuals had G at this position. This result strongly suggests that the mutation in the mitochondrial tRNALeu gene causes MELAS.

Acidosis, Lactic↗
PubMed1990

Distribution of Alzheimer's disease amyloid A4-generating enzymes in rat brain tissue.

To screen for putative amyloid A4-splitting proteinases, model peptide substrates homologous to the N- and C-terminal portions of the A4 protein were synthesized. The N-terminal A4-splitting enzyme activity was found to be higher in the hypothalamus and limbic area, compared with in the cerebral cortex and cerebellum in 2-month-old rat. The activity decreased throughout the brain in 20-month-old rat. On the other hand, the activity of the putative C-terminal A4-splitting enzyme was significantly higher, 1.4-fold, in the hippocampus than in the cerebral cortex in the young rat. The activity also significantly decreased in the brain of 20-month-old rat, but was still higher in the cerebral cortex, hippocampus and cerebellum.

Aging↗
PubMed1990

Expression of cellular retinoic acid binding protein in the developing nervous system of mouse embryo.

The expression of cellular retinoic acid binding protein, CRABP, in developing mouse embryos was immunohistochemically analyzed. Differentiating young neurons and neuronal fibers in the myelencephalon, metencephalon, mesencephalon and spinal cord in 10.5- and 12.5-day embryos showed intense expression of CRABP, but undifferentiated cells in the neural tube did not. Neural tissue in 16.5-day embryos expressed less amount of binding protein than the tissues of the younger stages. These expressions of CRABP suggest that retinoic acid participates in neurogenesis at early developmental stages via expression of cellular retinoic acid binding protein.

Animals↗