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Biomedical subjects

T Miyoshi

Publications and source records attributed to T Miyoshi.

At least 73 records · Page 4Linked to original sources
PubMed1999

Effect of freeze-dried soybean curd (tofu) on various bodily functions.

The present study was designed to examine the effect of freeze-dried soybean curd (tofu) on various bodily functions. The dietary experiment consisted of 4 days of a non-prescribed ordinary diet, 10 days of an experimental diet that contained 190 g of meat contributing about 38 g of protein (hereinafter referred to as the "meat period"), and 39 days of an experimental diet that contributed vegetable protein, i.e., freeze-dried tofu, corresponding to the protein that 190 g of meat would provide (hereinafter referred to as the "freeze-dried tofu period"). Three eggs (about 150 g) and 180 ml of cow's milk were prescribed for the daily diet, and staple and other foods were dispensed freely during both the meat and the freeze-dried tofu periods. The results showed that serum cholesterol levels and diastolic blood pressure significantly decreased in the freeze-dried tofu period as compared with the meat period. Freeze-dried tofu was found to be a valuable food for preventing lifestyle-related chronic diseases.

Adult↗
PubMed1999

[A successfully treated parkinsonian patient with neuroleptic malignant syndrome complicated by status epilepticus and disseminated intravascular coagulation].

A 57-year-old woman with a 7-year history of Parkinson's disease was admitted to our hospital because of a high fever, disturbance of consciousness, increased muscular rigidity, tachycardia and hyperhidosis after she stopped taking her prescribed levodopa + carbidopa (Menesit) 400 mg/day. In the laboratory examinations, the erythrocyte sedimentation rate was 109 mm/h, thrombocytes 7.8 x 10(4)/mm3, fibrinogen 457 mg/dl, FDP 74.8 micrograms/dl, thus suggesting disseminated intravascular coagulation (DIC). According to her biochemical examination, the serum AST (253 IU/l), ALT (178 IU/l), CK (7115 IU/l) and BUN (25 mg/dl) levels were all increased. These laboratory data and the clinical course indicated the patient to be suffering from neuroleptic malignant syndrome (NMS) with DIC. She was diagnosed to have NMS associated with DIC. She was treated with dantrolene sodium, bromocriptine, and gabexate mesilate, and her symptoms thereafter gradually improved. On day 7, she developed status epilepticus in spite of the clinical improvement in her symptoms of NMS and DIC including a clouding of consciousness. The status epilepticus was also attenuated by the use of thiamylal sodium. Patients with Parkinson's disease associated with NMS are considered to have a low incidence of DIC, status epilepticus, and in Japan this may be the first case report of the successful treatment of NMS with DIC and status epilepticus in a patient with Parkinson's disease.

Anticoagulants↗
PubMed1998

Activation of cAMP-dependent C1- currents in guinea-pig paneth cells without relevant evidence for CFTR expression.

1. To determine whether Paneth cells exhibit functional expression of cAMP-activated Cl- currents and molecular expression of the cystic fibrosis transmembrane conductance regulator (CFTR), we applied whole-cell patch clamp and single-cell mRNA analysis by reverse transcription (RT) followed by polymerase chain reaction (PCR) amplification to single Paneth cells in crypts isolated from the guinea-pig small intestine. 2. Prominent activation of Cl- currents was consistently observed after stimulation with dibutyryl cAMP and forskolin or with vasoactive intestinal polypeptide (VIP). The cAMP-activated Cl- current was inhibited by removal of intracellular ATP or administration of an inhibitor of protein kinase A. 3. Many of the biophysical and pharmacological properties of the currents were phenotypically similar to those of the CFTR Cl- channel, such as the ohmic current-voltage relationship, the anion selectivity with a Type III sequence (Br- > Cl- > I- >> F- >= gluconate-), I--induced blockage, insensitivity to a stilbene-derivative Cl- channel blocker, and sensitivity to a carboxylate analogue Cl- channel blocker. The sensitivity of the current to glibenclamide was, however, much weaker than that reported for the CFTR Cl- channel current. In contrast to the time independence of CFTR currents, the inward component of the Paneth cell Cl- currents exhibited inactivation kinetics. 4. Expression of CFTR mRNA could not be detected by RT-PCR analysis in almost all single Paneth cells, although its expression was consistently detected at the whole-crypt level. The presence of a small number of CFTR-expressing epithelial cells, which were scattered both in villi and crypts but not at the crypt base where Paneth cells were located, was demonstrated by immunocytochemistry. 5. Taken together, it appears that guinea-pig Paneth cells functionally express cAMP-activated Cl- conductance without relevant evidence for molecular expression of CFTR. Functional expression of VIP receptors in the Paneth cells was also demonstrated.

Animals↗
PubMed1998

The effects of 4-aminopyridine on motor evoked potentials in multiple sclerosis.

In order to study the effects of 4-aminopyridine (4-AP) on impulse conduction in multiple sclerosis (MS), we studied motor-evoked potentials (MEPs) in the upper (U/E) and lower extremities (L/E) of six MS patients with stable spastic paraparesis before and after intravenous administration of 4-AP. As a result, we found a significant increase in mean amplitudes in U/E and L/E (P = 0.008) and a significant decrease in the variability of onset latencies in L/E (P = 0.017) without any significant changes in mean and shortest onset latencies. In four limbs of three patients in whom there were no detectable MEP responses before 4-AP administration, definite responses were elicited after 4-AP administration. 4-AP seems to have its therapeutic effects by improving impulse conductivity in demyelinated nerve fibers or by enhancing central or peripheral synaptic transmission, which thus results in coordinated contractions of more muscle fibers in MS.

4-Aminopyridine↗
PubMed1998

Primary structure and functional expression of a novel non-selective cation channel.

A non-selective cation channel is believed to play important roles in various tissues. A novel complementary DNA encoding non-selective cation channel was isolated from MIN6, a mouse insulin secreting beta-cell line. This channel (mNSC1) conducts predominantly monovalent cations in Xenopus oocytes and is selective for cations over anions (PK/PCl = 10). The current was completely blocked by lanthanum and niflumate. The mNSC1 of 423 amino acids contains a characteristic leucine repeat and unique membrane topology. The messenger RNA of this channel are abundant in the brain, heart, and lung. We may therefore conclude that studies with this channel will provide important information for understanding physiological functions of the excitable cells as well as non-excitable epithelia.

Amino Acid Sequence↗
PubMed1998

High frequency expressions of CD44 standard and variant forms in non-small cell lung cancers, but not in small cell lung cancers.

BACKGROUND AND OBJECTIVES: Organ specificity has been demonstrated in the mode of CD44 expression among several cancers. METHODS: We examined the expressions of CD44 standard (CD44s) and CD44 variants (CD44v) in 14 cell lines (small cell lung cancer (SCLC): 5, non-small cell lung cancer (NSCLC): 9 and 20 surgically resected samples (SCLC: 7, NSCLC: 13) of lung cancer using reverse transcription polymerase chain reaction and immunohistochemistry. RESULTS: Although both NSCLC and SCLC expressed CD44s, the frequency and intensity of CD44s expression in NSCLC were different from those in SCLC: cell lines, 89% vs. 40%; tumor samples, 100% (diffusely stained) vs. 57% (focally stained). CD44s expression was partially or completely repressed in SCLC. However, NSCLC frequently expressed CD44v, but SCLC expressed infrequently: cell lines, 67% vs. 20%; tumor samples, 69% vs. 0%. The N-417 line, which only expressed some CD44v in SCLC, falls SCLC and NSCLC both in biomarkers and in growth patterns. CONCLUSIONS: CD44 expression was repressed in SCLC but was enhanced in NSCLC.

Adenocarcinoma↗
PubMed1998

Functional recovery of vision in regenerated optic nerve fibers.

Retinal ganglion cells (RGCs) of adult mammals normally suffer from retrograde cell death after optic nerve section. However, with transplantation of a segment of peripheral nerve (PN), their axons can regenerate and regrow through the graft. When properly guided, the regenerated axons make functional synapses with the target cells in the superior colliculus. Two months after PN graft we studied the number and morphology of RGCs with regenerated axons in adult cats. Number of regenerated RGCs was a few percent of the total population and, among various RGC types, alpha cells revealed the greatest ability for axonal regeneration and ON-center RGCs tended to regenerate better than OFF-center cells. While dendritic field dimension of RGCs with regenerated axons was mostly preserved, their regenerated axons were thinner than normal optic axons and mostly unmyelinated. The RGCs with regenerated axons revealed normal physiological properties in response to visual stimuli, and were classifiable into Y, X or W cells. In accordance with morphological results, Y cells (morphological alpha cells) were most frequently sampled. In hamsters and rats it has been shown that the animals with reconstructed retinocollicular pathway by the PN graft reveal behavioral recovery of visual function. However, in the cat, trials are still in progress to reconstruct the retinogeniculate pathway. The present status of researches on optic nerve regeneration of adult mammals using the PN graft is reviewed, and some future directions discussed.

Action Potentials↗
PubMed1998

3-Ketosteroid-delta1-dehydrogenase of Rhodococcus rhodochrous: sequencing of the genomic DNA and hyperexpression, purification, and characterization of the recombinant enzyme.

The gene encoding 3-ketosteroid-Delta1-dehydrogenase from Rhodococcus rhodochrous was cloned and sequenced. The gene (ksdD) consists of 1,536 nucleotides and encodes an enzyme protein of 511 amino acid residues. The amino terminal methionine residue was deleted in the mature protein. The amino acids involved in the flavin binding site are conserved in the dehydrogenase sequence. The deduced amino acid sequence is highly homologous to that from Arthrobacter simplex but less so to that from Pseudomonas testosteroni. Upstream of the gene was located a heat shock protein gene, dnaJ, and downstream, a gene of a hypothetical protein. The enzyme gene was ligated with an expression vector to construct a plasmid pDEX-3 and introduced into Escherichia coli cells. The transformed cells hyperexpressed the 3-ketosteroid-Delta1-dehydrogenase as an active and soluble protein at more than 30 times the level of R. rhodochrous cells. Purification of the recombinant 3-ketosteroid-Delta1-dehydrogenase from the E. coli cells by a simplified procedure yielded about 13 mg of enzyme protein/liter of the bacterial culture. The purified recombinant dehydrogenase exhibited identical molecular and catalytic properties to the R. rhodochrous enzyme.

Amino Acid Sequence↗
PubMed1998

[A case of severe hypernatremia complicated with rhabdomyolysis].

We report a 45-year-old male patient with severe hypernatremia followed by rhabdomyolysis and acute renal failure. He had developed hypernatremia for two years after a surgery for an intraventricular AVM involving the hypothalamic area, which was fed by the anterior cerebral artery. He was admitted to our hospital because of progressive muscle weakness. Because of loss of water intake due to impaired thirst sensation, he developed severe hypernatremia (191mEq/l) and marked rhabdomyolysis (CK 17,772 IU/l). He was treated with fluid supplement and hemodialysis for acute renal insufficiency. He had no thirst feeling. Blood studies revealed hyporeactivity to ADH in spite of marked hypernatremia and hyperosmorality. Therefore his condition was considered as adipsic hypernatremia. We concluded that rhabdomyolysis of this case was caused by severe hypernatremia. On reviewing the literature, only a few cases of rhabdomyolysis due to hypernatremia have been reported.

Acute Kidney Injury↗
PubMed1997

Isolation and characterization of D-threonine aldolase, a pyridoxal-5'-phosphate-dependent enzyme from Arthrobacter sp. DK-38.

D-Threonine aldolase is an enzyme that catalyzes the cleavage of D-threonine into glycine and acetaldehyde. Its activity was found in several genera of bacteria such as Arthrobacter, Alcaligenes, Xanthomonas, and Pseudomonas, but not in yeasts or fungi. The enzyme was purified to homogeneity from one strain, Arthrobacter sp. DK-38. The enzyme appeared to consist of a single polypeptide chain with an apparent molecular mass of 51 kDa. This enzyme, as well as L-threonine aldolase, requires pyridoxal 5'-phosphate (pyridoxal-P) as a coenzyme. Unlike other pyridoxal-P enzymes, D-threonine aldolase also requires a divalent cation such as Co2+, Ni2+, Mn2+, or Mg2+ for its catalytic activity. The enzyme completely lost its activity in the absence of either pyridoxal-P or a divalent cation. A divalent cation was also essential for the thermal stability of the enzyme. The metal-free enzyme tends to become thermally unstable, resulting in the irreversible loss of its catalytic activity. The enzyme is strictly D-specific for the alpha-position, whereas it cannot distinguish between threo and erythro forms at the beta-position. Thus, D-threonine and D-allothreonine act as substrates of the enzyme, but their kinetic parameters are different; the Km and Vmax values are 3.81 mM and 38.8 micromol x min(-1) x mg(-1) toward D-threonine, and 14.0 mM and 102 micromol x min(-1) x mg(-1) toward D-allothreonine. respectively. The aldolase reaction is reversible, and the enzyme is therefore able to produce nearly equimolar amounts of D-threonine and D-allothreonine through C-C bond formation between glycine and acetaldehyde. The enzyme also acts, in the same manner, on several other D-beta-hydroxy-alpha-amino acids, including D-beta-phenylserine, D-beta-hydroxy-alpha-aminovaleric acid, D-beta-3,4-dihydroxyphenylserine, and D-beta-3,4-methylenedioxyphenylserine.

Acetaldehyde↗
PubMed1997

Chick osteocyte-derived protein inhibits osteoclastic bone resorption.

In order to investigate the role of osteocytes in bone resorption, we examined the homogenate and conditioned medium from purified chick calvarial osteocytes in a pit-formation assay using unfractionated bone cells from mice. The osteocyte homogenate markedly inhibited pit formation, whereas the conditioned medium of osteocytes had no effect. This inhibitory activity was not the result of cytotoxicity of the homogenate. A novel bone-resorption-inhibitory protein was purified from collagenase-digested chick calvarial fragments enriched in osteocytes. The inhibitory protein, of molecular mass 18.5 kDa, showed significant dose-dependent inhibition of pit formation by unfractionated bone cells from mice and rabbits, and by human giant tumour cells. This protein also inhibited the bone-resorbing activity of purified osteoclasts in the pit-formation assay in the absence of other effector cells. Microinjection of the protein into osteoclasts caused disruption of the podosomes in the cells. The N-terminal 25-amino-acid sequence of the protein showed 68% identity to a part of Rho-GTP-dissociation inhibitor. Thus chick calvarial osteocytes may be involved in the regulation of bone resorption by osteoclasts.

Amino Acid Sequence↗
PubMed1997

Cytotoxic glycosides from Albizia julibrissin.

During the course of a study of leguminous plants, cytotoxicity was demonstrated by the crude saponin fraction of Albizia julibrissin. Following chromatographic purification, the structures of three novel saponins, julibrosides I-III (1-3), inclusive of a cytotoxic principle, were elucidated. A comparison of the cytotoxicity of julibrosides (1-3) and their prosapogenins (4-15) prepared by alkaline hydrolysis clearly indicated that both an alpha-L-arabinofuranosyl-(1-->4)-[beta-D-glucopyranosyl-(1-->3)]-alpha- L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl ester unit and a monoterpene-quinovopyranosyl moiety are crucial substituents for cytotoxicity among this class of compounds. The hydroxy group at C-16 of aglycon may play an important role in mediating cytotoxicity, and the N-acetyl-glucosamine moiety at C-3 seems to enhance activity because 3 showed the strongest cytotoxicity.

Antineoplastic Agents, Phytogenic↗
PubMed1997

High frequency of p53 protein expression in thymic carcinoma but not in thymoma.

Thymic epithelial tumours are broadly classified into thymomas and thymic carcinomas. Although both tumours occasionally show invasive growth, they exhibit different clinical and biological findings. The oncogene and anti-oncogene in thymic epithelial tumours have not been evaluated fully. We investigated the expression of p53 protein by immunohistochemical analysis using the anti-p53 polyclonal antibody (CM-1) in 17 thymomas and 19 thymic carcinomas. We also examined p53 gene (exon 5-8) mutation in 18 thymic carcinomas by using polymerase chain reaction-single-strand conformation polymorphism methods and direct sequencing. Of the thymoma cases, only one invasive thymoma showed focal nuclear staining. Fourteen of the 19 thymic carcinomas (74%) showed nuclear staining. Point mutations of the p53 gene were recognized in only 2 of the 18 thymic carcinomas (11%). One was the mutation C to T transition in the first letter of codon 222 in exon 6, which results in the amino acid substitution from proline to serine. Another was a silent mutation. p53 protein accumulation is highly frequent in thymic carcinomas but not in thymomas, and gene mutation is uncommon in thymic carcinomas.

Adult↗
PubMed1997

The effects of physician in-migration to rural Colorado (1992 to 1995).

This paper reports the results of an analysis of the American Medical Association Masterfile. The purpose of this study was to examine changes in health care accessibility in rural Colorado from 1992 to 1995, and to describe the pattern of in-migration of physicians to nonmetropolitan statistical area counties of the state during that period. The number of direct patient care providers increased from 532 to 700 (31.6%) during the three-year period vs. a growth of 11.2 percent in the general population of nonmetropolitan statistical area counties. Of the 700 physicians serving residents of Colorado's 52 rural counties, 308 (44%) had been practicing in their community since 1992. The rate of departure from nonmetropolitan statistical area practice sites in 1992 was 26.4 percent (140 of 532). Physicians new to their rural practice locations were younger and proportionally more female, but they were similar in primary medical specialty to doctors who had remained in their 1992 sites. Population to physician and to primary care physician ratios were much more favorable for 1995 than for 1992. Accessibility to care was most improved in counties with fewer than 10,000 inhabitants.

American Medical Association↗
PubMed1997

Melanin-concentrating hormone acutely stimulates feeding, but chronic administration has no effect on body weight.

Melanin-concentrating hormone (MCH) has recently been proposed as both a central stimulator and an inhibitor of food intake. To clarify its role, we investigated the effects of MCH and the prepro-MCH-derived peptide neuropeptide E-I injected intracerebroventricularly (icv) in rats. MCH (0.15-15 micrograms) was injected icv at the beginning of the light phase. Food intake at 2 h showed a dose-dependent increase from 325 +/- 7% of the control value (1.5-microgram dose; P < 0.05) to 462 +/- 30% of the control value (15-microgram dose; P < 0.005). When 10 ng, 100 ng, and 5 micrograms MCH were injected icv at the beginning of the dark phase, only 5 micrograms stimulated feeding (166 +/- 16% of the control value; P < 0.05). At no dose did MCH inhibit feeding. Twice daily icv injections of MCH (5 micrograms) caused an average 197 +/- 9% increase in 2-h food intake for the first 5 days. Injections from days 6-8 did not stimulate feeding. Food intake and body weight at 24 h remained unchanged. Intracerebroventricular neuropeptide E-I had no effect on food intake alone and did not alter MCH-induced feeding. These studies show a dose-dependent stimulation of feeding by acute central administration of MCH. Tolerance is seen with chronic administration. These findings support a role for MCH in the immediate regulation of food intake, but not in body weight control.

Animals↗
PubMed1997

The expression of the CD44 variant exon 6 is associated with lymph node metastasis in non-small cell lung cancer.

Recently, it was suggested that splice variants of the surface glycoprotein CD44 (CD44v) were associated with tumor metastasis in some cancers. We examined the expression of variant forms of CD44 in 31 non-small cell lung carcinomas (NSCLCs) and in 8 normal lung tissue samples by reverse transcription-PCR (RT-PCR). CD44v3, CD44v5, CD44v6, and CD44v7 were not expressed or were weakly expressed in normal lung tissue (0 of 8). In contrast, CD44v3, CD44v5, CD44v6, or CD44v7 was expressed in 28 of 31 (90.3%) NSCLCs. Additionally, we examined the expression of CD44v6, which has been shown to be related to metastasis, in 5 normal lungs and 30 NSCLCs by RT-PCR and immunohistochemical analysis to clarify which cells express CD44v6 in NSCLC specimens. Thirty-six of 61 (59%) NSCLCs variably expressed CD44v6 by RT-PCR, and cancer cells were selectively immunostained by anti-CD44v6 antibodies in 23 of 30 (76.7%) NSCLCs. The results of immunohistochemical analysis almost correlated with those of RT-PCR. NSCLCs with lymph node metastasis expressed significantly more v6 exon than did those without lymph node metastasis [23 of 29 (79.3%) versus 13 of 32 (40.6%); P < 0.01]. There was a significant association between the intensity of v6 expression by RT-PCR and the frequency of cases showing lymph node metastasis (Cochran-Armitage's test, P < 0.002). In conclusion, this study demonstrated that in NSCLC, a number of variant forms of CD44 are frequently expressed, although these variants are infrequently expressed in normal lung tissue, and that the expression of CD44v6 is particularly associated with lymph node metastasis in NSCLC.

Adult↗