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Biomedical subjects

M Masuda

Publications and source records attributed to M Masuda.

At least 307 records · Page 17Linked to original sources
PubMed1995

[Application of quantitative assay for endotoxin using immobilized histidine and filtration plate to parenteral drugs].

We improved the Limulus amebocyte lysate (LAL) test for endotoxins in parenteral drugs using immobilized histidine and a filtration plate. In order to deal with many samples at the same time and to apply to a routine assay, we used a filtration plate having 96 wells instead of a filter unit with a working volume of 2 ml. LAL test-affecting substances which are contained in a parenteral drug were separated from endotoxins by adsorbing endotoxins on immobilized histidine in the well of a filtration plate. Then the absorbed endotoxins were allowed to react with LAL reagent in the same well. We defined that this method had the higher precision than conventional methods and was not influenced by the concentrations of endotoxin and parenteral drugs. Hence we examined the recovery of endotoxin spiked to 23 kinds of parenteral drugs by this method, as a result, 100 +/- 25% of recovery was obtained from 17 kinds of them.

Endotoxins↗
PubMed1995

Mechanism of hypertension induced by chronic inhibition of nitric oxide in rats.

In order to clarify the mechanism of hypertension induced by a nitric oxide (NO) synthase inhibitor, L-NG-nitro-L-arginine (LNNA), metabolites of NO, catecholamines, and hemodynamic parameters were measured during 7 days of oral administration of LNNA in rats. Control rats received either L-arginine (L-Arg) or the vehicle. systolic blood pressure, measured by the tall-cuff method was elevated throughout the period of LNNA administration, but that in the two control groups was not influenced by treatment. Heart rate decreased on the second day only in LNNA-treated rats. Although L-Arg treatment had no influence, LNNA markedly decreased the plasma level and the urinary excretion of nitrate ions (NO-3). Urinary excretion of noradrenaline was significantly decreased on the second day of LNNA administration and returned to the control level thereafter. When hemodynamic changes were measured by using radioactive microspheres, LNNA was found to increase blood pressure by markedly increasing total peripheral resistance. Cardiac output was decreased by LNNA. L-Arg, again, did not influence the hemodynamic variables as compared with the vehicle control group. The regional vascular resistance index was increased by LNNA in many tissues and organs, except the brain and the heart. Regional blood flow, on the other hand, was significantly decreased only in the liver and skin by LNNA. The marked reduction in NO3- in urine by LNNA-treatments may indicate that the measured NO3- is exclusively of endogenous origin, and that inhibition of NO production causes elevation of blood pressure by constricting peripheral arteries. Sympatholytic responses by the baroreceptor reflex were thereby evident only on the second and the third days, which was indicated by bradycardia and suppression of noradrenaline excretion into urine. These results indicate that the inhibition of NO synthase actually decreases production of endogenous NO, and that the hypertension caused by decreases in NO production is due to elevation of total peripheral vascular resistance.

Animals↗
PubMed1995

Mutagenicity studies with palm fruit carotene.

The mutagenicity of palm fruit carotene was examined using the reverse mutation test with bacteria, the chromosomal aberration test with mammalian cells and the micronucleus test in mice. The carotene induced neither reverse mutation in Salmonella typhimurium TA98, TA1537, TA100, TA1535 and in Escherichia coli WP2uvrA, nor structural and numerical (polyploidy) chromosomal aberrations in the Chinese hamster fibroblast cell line (CHL). In addition, no increase in micronucleated polychromatic erythrocytes was elicited in the micronucleus test in CD-1(ICR) male mice. It is concluded that palm fruit carotene had no mutagenic activity in these in vitro and in vivo tests.

Animals↗
PubMed1995

Melanocytes in the dark cell area of human vestibular organs.

By using surgical materials obtained from 7 cases of vestibular schwannoma, the ultrastructure of melanocytes in the dark cell area of human vestibular organs was examined by light microscopy and electron microscopy. Paraffin sections were stained with hematoxylin and eosin. Glutaraldehyde-fixed specimens were observed by electron microscopy. Melanocytes were found in the subepithelial layer of the dark cell area. Melanocytes had round or spindle-shaped nuclei and clear cytoplasm with brown pigment granules which were thought to be melanin granules. Besides melanocytes, there were fibroblasts and small blood vessels. By electron microscopy we found melanocytes with round shaped melanosomes in various stages of pigmentation, well-developed Golgi apparatus and endoplasmic reticulum in the cytoplasm, and many cytoplasmic processes. There were pinocytotic vesicles just under the limiting membrane of the melanocytes, and intermediate filaments were abundant in the cytoplasm. On the other hand long-spacing collagen was found in the connective tissue area around melanocytes.

Adult↗
PubMed1995

Anti-peptide antibodies to the P4502D subfamily in rat, dog and man.

1. In order to obtain specific antibodies of the P4502D subfamily, we generated two anti-peptide antibodies against synthetic peptides, DPAQPPRD (peptide A) and DPTQPPRH (peptide B). The sequence of peptide A occurs in rat P4502D2, P4502D4 and human P4502D6, whereas the sequence of peptide B occurs in the dog P4502D subfamily. These sequences are closely related to an epitope of liver/kidney microsomal autoimmune hepatitis. 2. In immunoblotting studies, the anti-peptide antibody against peptide A recognized a 49-KDa protein in microsomes derived from human lymphoblasts expressing P4502D6 and rat liver. It showed no crossreactivity with microsomes from dog liver. In contrast, the anti-peptide antibody against peptide B recognized a 49-KDa protein only in microsomes of dog liver. These indicate that each anti-peptide antibody has the specificity for the respective sequences of the members of P4502D subfamily, with the species investigated herein. 3. In immunoinhibition studies, the anti-peptide antibodies against peptide B inhibited bunitrolol 4-hydroxylation and propranolol 4,5-hydroxylation, which are mediated by the dog P4502D subfamily. These data suggest that the anti-peptide antibodies against peptide B bind to the native and denatured forms of the P4502D subfamily. 4. The present study has demonstrated that the anti-peptide antibodies against this region are useful for studying the members of the P4502D subfamily.

Adrenergic beta-Antagonists↗
PubMed1995

[Prognostic factors for metastatic renal cell cancer].

We examined various prognostic factors of metastatic renal cell carcinoma. Patients who had metastasis at nephrectomy (A group, 38 cases) and those who had metastasis as recurrent tumors after nephrectomy (B group, 38 cases) entered in this study. Five-year survival rate of total cases after confirmation of metastatic foci was 15% and there was no statistical significant difference between A and B groups. Several pathological factors were related to poorer prognosis and included large diameters of original tumors, positive lymph nodes, higher grade tumors and non-clear cell type tumors. Patients who have a solitary lung metastasis showed better prognosis compared to those with multiple lung metastases or metastases of other organs. Two factors related to treatment were shown to contribute to better prognosis. These were the response to interferon alfa (IFN alpha) and the possibility of total resection of visible metastatic tumors. Patients who belong to A group were shown to achieve markedly better therapeutic benefit from IFN alpha or IFN alpha plus anticancer drugs. Five-year survival rate for the responders was 40%, as compared to less than 5% for the non-responders. Ten-year survival rate for patients with metastasis who had undergone complete resection of visible tumor was 50%, and the for patients belonging to B group Showed 80%. We concluded that these prognostic factors should be considered to decide how to select patients with metastatic renal cell cancer.

Adult↗
PubMed1995

[Clinical investigation of grade-up superficial bladder cancer].

Between January 1977 and December 1993, 249 patients with grade 1 or grade 2 superficial bladder cancer were initially treated at Yokohama City University Hospital. Eighty-six patients (33%) had recurrent tumors after initial resection, and sixteen recurrent cases were so-called grade-up tumors that is, grade 3 originating from grade 1 or grade 2 tumor. The morphology of the grade-up tumors mostly showed non-papillary and invasive type. Positivity for urinary cytology of grade-up tumors was 88%. The five-year survival rate of the patients with grade-up tumors was 85% after initial resection of grade-up patients and 48% after treatment of grade-up tumors. The five-year survival rate of the patients with grade-up tumors who were treated by total cystectomy was 72%, whereas that in the patients who were treated by bladder preservation therapy showed a 13% five-year survival rate and all of the six patients died of cancer during the six-year follow-up period. These findings suggest that patients who have grade up tumors should be treated by radical treatment with radical cystectomy.

Adult↗
PubMed1995

[Combination therapy with interferon-alpha and continuous infusion of 5-fluorouracil for advanced renal cell carcinoma].

Between May 1990 and April 1994, eleven patients with metastatic renal cell carcinoma received a combination therapy with interferon-alpha (IFN alpha) and 5-fluorouracil (5FU). IFN was administered intramuscularly six or ten million units three times per week for 4 weeks and 300 mg/m2 of 5FU was administered by continuous intravenous infusion daily for 4 weeks. Of 8 evaluable patients, two had a partial response (25%) two had a minor response (25%), and two had a stable disease (25%). The common side effects of the regimen were flu-like symptoms (91%), mucositis (64%) and leukopenia (75%). Three patients refused this therapy because of severe mucositis or stomatitis. Although the combination of IFN and 5FU in patients with metastatic renal cell carcinoma had some efficacy, this regimen had severe toxicity especially for the gastrointestinal (GI) tract. None of the patients could be administered the initially scheduled dosage of 500 mg/m2 of 5FU. The dose limiting factor of this regimen is considered to be GI symptoms.

Aged↗
PubMed1995

[Complete response of lung metastasis from bladder cancer by combination chemotherapy with methotrexate, epirubicin and cisplatin: a case report].

We report a case of lung metastasis from bladder cancer effectively responding to a combination chemotherapy using methotrexate, epirubicin and cisplatin (MEC therapy). A 78-year-old man with high grade bladder cancer underwent total cystectomy on June 5, 1991. He was pointed out to have an abnormal shadow on the plain chest X-ray on August 14, 1992. Computed tomography demonstrated multiple lung metastasis. MEC combination chemotherapy was applied for this case. After 3 courses of MEC therapy, computed tomography showed marked regression of tumor. He has been alive for 12 months with no evidence of disease after chemotherapy. Toxicity of MEC therapy were moderate myelosuppression and mild anorexia and alopecia. These toxicity was adequately tolerable by the 78-year-old patient. This case suggests that MEC therapy is effective against advanced bladder cancer.

Aged↗
PubMed1995

[Activated coagulation factors in various thrombotic diseases].

Various hemostatic abnormalities have been reported and excess activation of coagulation factors, such as prothrombin, factor VII, factor IX, and factor XI, have been detected in thrombotic diseases states by various assay systems. We recently developed the enzyme-linked differential immunoassay for activated factor XI-alpha 1 antitrypsin complex (FXIa-alpha 1 AT) and applied it with other assays for activated factors such as thrombin-antithrombin III complex (TAT) to detect the hypercoagulable state in clinical samples. In patients with DIC, the FXIa-alpha 1 AT level in plasma increased before onset of DIC. In patients with non-insulin-dependent diabetes mellitus, FXIa-alpha 1AT and TAT levels were increased in the patient plasma. FXIa-alpha 1AT was related to the severity of urinary albumin excretion, whereas TAT was not. Plasma FXIa-alpha 1AT levels were significantly increased in patients with angiographically proven coronary artery disease, and showed a positive correlation with TAT, fibrinogen, and Lp(a). Evaluation of activated coagulation factor provides useful information on the diagnosis of thrombotic disease.

Arteriosclerosis↗
PubMed1995

Purification and characterization of a dog cytochrome P450 isozyme belonging to the CYP2D subfamily and development of its antipeptide antibody.

Species differences in the metabolism of bunitrolol (BTL) and propranolol (PL) in liver microsomes from rats and dogs were investigated. Hepatic microsomes from dogs lacked the ability to catalyze PL 7-hydroxylation, which is mediated by the CYP2D subfamily in rats. This suggested that dogs might lack the CYP2D subfamily; however, the antibody against cytochrome P450 (P450) BTL (CYP2D2) recognized a protein of approximately 49 kDa in hepatic microsomes from dogs, indicative of the presence of the CYP2D subfamily in dogs. The P450 purified from dog hepatic microsomes was designated P450 Canis familiaris (CF)1. It cross-reacted with the antibody against P450 BTL. The apparent molecular weight of the purified P450 CF1 was estimated to be 49 kDa. Its N-terminal amino acid sequence resembled the sequences of the members of the rat CYP2D subfamily and was the same as the sequences of the dog CYP2D subfamily, as deduced from the cDNA, except for the lack of four residues at the N-terminal. P450 CF1 could mediate metabolism of BTL and PL. P450 CF1, however, could not mediate PL 7-hydroxylation, which is almost exclusively mediated by CYP2D in rats. These findings indicate that P450 CF1 belongs to the CYP2D subfamily and that it differs functionally from the rat CYP2D subfamily. An antipeptide antibody against the synthetic peptide (DPTQPPRH), the sequence of which occurs in dog CYP2D at position 266-273 (S. Kirita et al., unpublished data), inhibited BTL 4-hydroxylase activity by 71% in dog hepatic microsomes at the substrate concentration of 0.01 M. This is further evidence that the CYP2D subfamily, in particular P450 CF1, is largely responsible for the oxidation of beta-blockers in dog hepatic microsomes.

Adrenergic beta-Antagonists↗
PubMed1994

Structure-activity relationships of an anti-HIV peptide, T22.

T22 ([Tyr5,12,Lys7]-polyphemusin II) has been shown to have a strong anti-human immunodeficiency virus (HIV) activity comparable to that of 3'-azido-2',3'-dideoxythymidine (AZT). We studied the structure-anti-HIV activity relationships of T22 and determined the following information. The number of Arg residues in the N-terminal and C-terminal regions of T22 is closely related with anti-HIV activity. Disulfide rings, especially the major disulfide ring, are indispensable for anti-HIV activity and maintenance of the secondary structure. Between two repeats of Tyr-Arg-Lys, which are a characteristic structure contained in T22, Tyr-Arg-Lys in the N-terminal portion is more closely related with anti-HIV activity. We found some compounds having a higher selectivity index (50% cytotoxic concentration/50% effective concentration) than that of T22.

Amino Acid Sequence↗
PubMed1994

Vagal efferent nerve-dependent inhibitory action of pancreatic polypeptide and peptide YY in conscious rats: comparison with somatostatin.

The release of pancreatic polypeptide (PP) and peptide YY (PYY) is regulated by the vagal nerve, and the inhibitory effect of these peptides on pancreatic exocrine secretion shows indirectly via a neural mechanism. To determine the role of the vagal nerve on the inhibitory action of these peptides on the pancreas, we compared the effect on the pancreatic response to bile and pancreatic juice diversion in conscious rats with and without vagotomy. We also studied this response in rats treated with capsaicin, because bile-pancreatic juice diversion is the most potent endogenous stimulation of pancreatic secretion in conscious rats. In addition, since somatostatin potently inhibits of pancreatic enzyme secretion, the effects of PP and PYY were compared with somatostatin. An intravenous infusion of 2.5 nmol/kg per h of PP and PYY significantly inhibited the pancreatic responses of bile and pancreatic juice diversion in animals with an intact vagal nerve and in those treated with capsaicin, whereas the same dose of peptides failed to inhibit pancreatic secretion in vagotomized rats. Somatostatin inhibited pancreatic secretion under all conditions tested. We concluded that the inhibitory action of PP and PYY on pancreatic secretion is fully mediated by the vagal efferent nerve although other multiple mechanisms are involved for the inhibitory action of somatostatin.

Animals↗
PubMed1994

Improvement of a d-biotin-hyperproducing recombinant strain of Serratia marcescens.

We previously reported that a recombinant strain, SB412(pLGM304), was constructed from acidomycin-resistant mutants of Serratia marcescens and produced 200 mg of d-biotin per liter of a medium containing sucrose and urea (Sakurai et al., 1993a, b). In the present work, we intended to improve the d-biotin production. Both ethionine and S-2-aminoethylcysteine resistances were added to the host strain SB412, producing d-biotin at 20 mg l-1, and a resultant strain, ETA23, producing it at 33 mg l-1, was obtained. Cells of ETA23 did not maintain pLGM304 stably after greater than 30 generations under non-selective culture conditions. A new recombinant plasmid, pLGM304P, was constructed so as to be composed of pLGM304 and the parB locus, a plasmid-stabilizing element. ETA23 stably maintained pLGM304P after 50 generations under non-selective culture conditions. ETA23(pLGM304) produced 250 mg l-1 of d-biotin in a shaking flask under batch culture conditions and 500 mg l-1 in a jar fermentor under fed-batch culture conditions.

Biotin↗
PubMed1994

Metaphase and anaphase in the artificially induced monopolar spindle.

By using monopolar spindles artificially induced in sea urchin embryos, we examined whether or not the presence of two opposing poles was an indispensable condition for keeping chromosomes at a fixed distance from the pole at metaphase and for the anaphase chromosome movement. Chromosomes were stained with Hoechst dye 33342 and their behavior was followed in the monopolar and the control bipolar spindles. In the monopolar spindle, chromosomes were first arranged on a curved metaphase plate and then spread on a part of the imaginary surface of a sphere whose center was the monopole. The estimated chromosome-to-pole distance was similar to that of bipolar spindles at metaphase and remained fixed until chromosomes started to move toward the pole. The average duration of metaphase in the monopolar spindle was 6 times longer than that in the bipolar spindle. The poleward movement of chromosomes in the monopolar spindle was similar to the anaphase A (chromosome-to-pole movement) in the bipolar spindle with respect to the velocity, duration, distance, and synchronization of migration. These results show that even half of the normal spindle has capacities for the arrangement of chromosomes at metaphase and for the anaphase A chromosome movement. Based on these results, we were able to exclude some existing theories of metaphase, such as the one based on the balance of forces between the two poles.

Anaphase↗
PubMed1994

Structural studies on the chondroitinase ABC-resistant sulfated tetrasaccharides isolated from various chondroitin sulfate isomers.

Various commercially available chondroitin sulfates, including an A isomer from whale cartilage, C and D isomers from shark cartilage, and an E isomer from squid cartilage, were exhaustively digested with a commercial highly purified Proteus vulgaris chondroitinase ABC. Gel chromatography of all digests yielded a disaccharide and an oligosaccharide fraction which was resistant to the enzyme digestion and which accounts for 20-31 mol% of the produced total oligosaccharides. Variably sulfated tetrasaccharides were isolated from the oligosaccharide fraction of each chondroitin sulfate isomer by HPLC, then characterized chemically and enzymatically. One disulfated and three trisulfated components were also characterized by 500-MHz one- and two-dimensional 1H NMR spectroscopy. The structures of one tetrasulfated, four trisulfated, and five disulfated tetrasaccharides with the common core structure, alpha-L-delta 4,5HexpA-(1-->3)-beta-D-GalpNAc-(1-->4)-beta-D-GlcpA-(1-->3) -D-GalpNAc, were determined. All isolated tetrasaccharides were resistant to the highly purified enzyme, but susceptible to the conventional, commercial chondroitinase ABC. The former was also inactive towards alpha-L-delta 4,5HexpA-(1-->3)-beta-D-GalpNAc-(1-->4)-beta-D-GlcpA-(1-->3) -D-GalpNAc isolated from chondroitin, beta-D-GlcpA-(1-->3)-beta-D-GlcpNAc-(1-->4)-beta-D-GlcpA-(1- ->3)-D-GlcpNAc from hyaluronan, and alpha-L-delta 4,5HexpA-(1-->3)-beta-D-GalpNAc4SO3(-)-(1-->4)-alpha-L-Id opA-(1-->3)-D- GalpNAc4SO3- from dermatan sulfate. These results indicate that, unlike the conventional enzyme, highly purified chondroitinase ABC cannot degrade tetrasaccharides irrespective of their sulfation profiles. The enzymatic action is size-dependent.

Carbohydrate Sequence↗
PubMed1994

Ultrastructure of melanocytes in the dark cell area of human vestibular organs: functional implications of gap junctions, isolated cilia, and annulate lamellae.

BACKGROUND: It is known that melanocytes exist in almost all parts of the inner ear, such as the cochlear duct, stria vascularis, Reissner's membrane, modiolus, vestibular organs in the region surrounding the cristae and maculae, semicircular canals, and pars rugosa of the endolymphatic sac. But there have been few studies using human materials, because of the difficulty of obtaining materials. We attempted to investigate the detailed ultrastructure of melanocytes in the vestibular organs of human inner ear. METHODS: Eight surgical specimens obtained from patients with vestibular schwannoma were studied by light microscopy and electron microscopy. RESULTS: Melanocytes were found in the subepithelial layer of the dark cell area. Melanocytes had round or spindle-shaped nuclei and clear cytoplasm with brown pigment granules. Besides melanocytes, there were melanophages, fibroblasts, and small blood vessels. Through electron microscopy we found melanocytes with round-shaped melanosomes in various stages of pigmentation, well-developed Golgi apparatus and endoplasmic reticulum in the cytoplasm, and many cytoplasmic processes. Gap junctions were occasionally found between the cytoplasmic processes. And there were pinocytotic vesicles just under the limiting membrane of melanocytes, and intermediate filaments were abundant in the cytoplasm. Isolated cilia of melanocytes, annulate lamellae, and fusiform banded structures in the connective tissue area around melanocytes were found. CONCLUSIONS: Melanocytes in human vestibular organs actively synthesize melanosomes. Frequent findings of isolated cilia and fusiform banded structures and the incidental existence of annulate lamellae may be an indicator of this metabolically activated state of melanocytes. Moreover, monitoring environmental changes by isolated cilia, melanocytes in the human inner ear could act not only as one cell but also as a group to achieve their physiological functions by means of information transmission through gap junctions.

Adult↗