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Biomedical subjects

M Masuda

Publications and source records attributed to M Masuda.

At least 361 records · Page 20Linked to original sources
PubMed1993

Construction of a Biotin-Overproducing Strain of Serratia marcescens.

We have isolated mutants resistant to acidomycin, a biotin analog, from Serratia marcescens Sr41. Strain SB304, resistant to 0.5 mg of acidomycin (frequently called actithiazic acid) per ml, produced 5 mg of d-biotin per liter of a medium containing sucrose and urea. Strain SB412, which was isolated from SB304 on a minimal agar plate containing 2 mg of acidomycin per ml and 0.1 mg of 5-(2-thienyl)-valeric acid per ml, produced 20 mg of d-biotin per ml. The two enzymes related to biotin synthesis were found to be released from biotin-mediated feedback repression in these mutants. Transductional analysis revealed that SB412 had acquired at least two mutations, one in the biotin operon locus and the other in an unknown locus distant from the biotin operon locus.

Journal Article↗
PubMed1993

Viral determinants that control the neuropathogenicity of PVC-211 murine leukemia virus in vivo determine brain capillary endothelial cell tropism of the virus in vitro.

PVC-211 murine leukemia virus (MuLV) is a neuropathogenic, weakly leukemogenic variant of the nonneuropathogenic, highly leukemogenic Friend MuLV (F-MuLV). Chimeric viruses constructed from PVC-211 MuLV clone 3d and F-MuLV clone 57 indicate that the env gene of PVC-211 MuLV contains the determinant(s) responsible for pathological changes in the central nervous system. However, sequences within the 5' one-third (AatII-EcoRI region) of the PVC-211 MuLV genome, which include the 5' leader sequence, the gag gene, and the 5' quarter of the pol gene, are also needed in conjunction with the env gene determinant(s) to cause clinically evident neurological disease in the majority of virus-infected animals after a short latency. In the presence of the AatII-EcoRI region of the PVC-211 MuLV genome, the PVC-211 MuLV env gene sequences encoding the amino-terminal half of the SU protein, which contains the receptor-binding region of the protein, were sufficient to cause rapidly progressive neurological disease. When PVC-211 MuLV, F-MuLV, and various chimeric viruses were tested for their ability to replicate in cultured brain capillary endothelial cells (BCEC), the primary site of PVC-211 MuLV replication within the central nervous system, there was a direct correlation between the replication efficiency of a virus in BCEC in vitro and its ability to cause neurological disease in vivo. This observation indicates that the sequences in PVC-211 MuLV that render it neuropathogenic affect its replication in BCEC and suggests that rapid and efficient replication of the virus in BCEC is crucial for the pathological changes in the central nervous system that result in development of neurological disease.

3T3 Cells↗
PubMed1993

[The role of the central monoaminergic nervous system relative to mechanisms of stress adaptation].

The difference of amine dynamics in central noradrenergic, dopaminergic and serotonergic systems of adaptive or non-adaptive rats to repeated restraint stress was investigated neurochemically. A single immobilization induced stress responses, such as reductions in growth rate, food intake, water intake and locomotor activity, and an increase in pain threshold. These responses disappeared after repeated immobilization 1 or 2 hr daily for 7 days, but not after 4 hr daily for 7 days. These results suggest that stress adaptation models should include the parameter of repeated exposure to restraint stress 1 or 2 hr daily for 7 days. In the frontal cortex, midbrain-thalamus, striatum, hypothalamus, medulla-pons, cerebellum, cervical cord, thoracic cord and lumbar cord of models with adaptability to repeated restraint stress, a marked increase in serotonin (5-HT) turnover was observed. This neurochemical change was seen in the hypothalamus and lumbar cord of non-adaptive models, but not in the other brain and spinal cord regions. Also, an increase in norepinephrine (NE) turnover in spinal cord regions was observed in adaptive models, but NE turnover was decreased in the frontal cortex, striatum or cervical cord of non-adaptive models. These findings suggest that enhancement of central 5-HT turnover and NE turnover in the spinal cord contribute to the formation of adaptation to repeated restraint stress.

Adaptation, Physiological↗
PubMed1993

Vestibular compensation in vestibular neuronitis: evaluation of positional nystagmus and caloric nystagmus.

We evaluated the vestibular functions, especially for positional nystagmus and caloric nystagmus, in 43 cases of vestibular neuronitis for long periods after its onset. It is shown that in the cases of vestibular neuronitis that were studied more than 10 years after the onset of the disease, the completed vestibular compensation changed or the vestibular compensation was still incomplete.

Caloric Tests↗
PubMed1993

[Testicular malacoplakia. Case report].

Testicular malacoplakia is an extremely rare condition; only 37 cases have been reported in the world literature. We hereby report a case of testicular malacoplakia. In over half of the cases of testicular malacoplakia, a preceding bacterial infection of a gram-negative rod has been known to occur, most commonly. Escherichia coli from urine or a suppurative lesion. This evidence may well be significant in explaining a possible initiative or contributing cause of malacoplakia. Orchiectomy is thought necessary to distinguish testicular malacoplakia from other scrotal conditions such as testicular cancer and granulomatous orchitis.

Diagnosis, Differential↗
PubMed1993

Heterogeneity of CD7+ 4- 8- 1- leukemia: usefulness of cytoplasmic antigen detection for subclassification.

We identified CD3 and myeloperoxidase (MPO) antigens in the cytoplasm of leukemic cells from 15 patients with CD7+ 4- 8- 1- leukemia. Seven patients, five of whom had a mediastinal mass, had only cytoplasmic CD3 (cCD3) antigen; these seven were regarded as possibly being of T-lineage type. Six patients, one of whom had a mediastinal mass, showed both cCD3 and MPO; they were considered to have mixed lineage type. Two patients had neither cCD3 nor cytoplasmic myeloid antigens; they were therefore considered to have stem cell type. These two latter types were considered as the subgroups: mixed lineage or stem cell type. Patients with T-lineage type were good responders to L-17M therapy; four out of five who received L-17M therapy achieved complete remission. There were significant differences between the two subgroups in relapse-free survival, patients with T-lineage type exhibiting better prognosis than other types (p < 0.05).

Adult↗
PubMed1993

Morphological responses of single endothelial cells exposed to physiological levels of fluid shear stress.

To investigate the basic processes underlying flow induced morphological changes of vascular endothelial cells (ECs), we have examined the responses of single ECs to fluid mechanical forces under controlled flow conditions in vitro. We made a parallel plate culture flow chamber which could be mounted on an inverted microscope equipped with various optical systems. Video-enhanced microscopic images were recorded with a time-lapse, laser video-disk recorder and then analyzed frame by frame. In contrast to ECs in a confluent monolayer, ECs in sparse culture did not show a parallel alignment to the flow direction even after a 100 h exposure to flow at a wall shear stress level of 10 dyne/cm2. However, rapidly after changing from a weak shear stress (1 dyne/cm2 or less) to a high shear stress (6 dyne/cm2 or more), sparsely cultured ECs extended lamellipodia predominantly on the downstream side and began to migrate preferentially downstream. If the viscosity of the circulating medium was raised by adding a small amount of methyl cellulose or polyvinylpyrrolidone, ECs exhibited these characteristic morphological changes under low wall shear rates (100 s-1 or less). We also found that these changes required Ca2+ in the circulating medium. These results indicate that single ECs can respond to flow in a rapid, shear stress and Ca2+ dependent manner.

Animals↗
PubMed1993

[Clinical observations on bladder cancer--difference in clinical features with age].

Three hundred and ninety-four patients with transitional cell carcinoma of the bladder who initially visited Yokohama City University Hospital were reviewed according to age group. The patients were divided into four groups, group A (less than 49 years old), group B (from 50 to 64 years old), group C (from 65 to 79 years old) and group D (more than 80 years old). The clinical characteristics as follows were obtained by statistical analysis compared with these four groups. No statistical significance was obtained about frequency of macroscopic hematuria as chief complaint. However, the younger age groups (A and B) tended to visit hospital later after the first symptom of hematuria. The older age groups (C and D) had multiple and large tumor at the first cystoscopic examination. The older age groups (C and D) had high stage and high grade tumor at the first roentgenological examination and transurethral biopsy or resection. The 5-year recurrence free rate after transurethral resection of bladder tumor (TUR-BT) of the older age group (D group) was lower than that of the other groups. The 5-year survival rate of older age group was lower than that of the younger age group. However, no statistical significance between the age groups existed concerning high grade or high stage tumor and survival after total cystectomy. We clarified here that the clinical features of elderly patients who have bladder cancer were significantly different from those of younger patients. Otherwise the prognosis of patients who have high grade and/or high stage bladder cancer were demonstrated to be poor regardless of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Clinical assessment of complement activation and leukocyte kinetics during cardiopulmonary bypass: the effect of cepharanthine].

Complement activation and leukosequestration to the lung was studied during cardiopulmonary bypass in eleven patients undergoing cardiac operation without blood transfusion. Six patients (group I) received methylprednisolone before and after the bypass, and the other five (group II) received cepharanthine (biscoclaurin alkaloid) before the bypass associated with methylprednisolone therapy. Leukosequestration to the lung was observed at the time of reperfusion of the lung only in group I, although complement activation estimated by the increase of C 4 a and C 3 a was quite similar in both group. Cepharanthine prevented the sequestration of the leukocyte to the lung may be by its membrane stabilizing effect.

Adult↗
PubMed1993

Regio- and stereoselective propranolol metabolism by 15 forms of purified cytochromes P-450 from rat liver.

Regio- and stereoselectivity of cytochrome P-450-mediated propranolol metabolism (4-, 5- and 7-hydroxylations and N-desisopropylation) was studied using 15 purified cytochrome P-450 species. With each purified cytochrome P-450 species, the regioselectivity was distinct and different between the two optical isomers used as substrates. The stereoselectivity was different depending on the position of propranolol to be metabolized. The regio- and stereoselectivity was altered when substrate concentration was altered, suggesting that the kinetics of the reactions are different depending on the positions of propranolol to be metabolized. Furthermore, the selectivity and its manner of alterations with substrate concentrations were different among all cytochrome P-450 species used. Propranolol, with its multiple metabolic pathways and optical isomers, is an extremely interesting substrate for characterization of cytochrome P-450 species.

Amino Acid Sequence↗
PubMed1993

[A case of benign mesothelioma of the tunica vaginalis testis].

A case of benign mesothelioma of the tunica vaginalis testis is described. A 56-year-old man with no history of asbestos exposure presented with a swelling of the left scrotal content. A physical examination revealed a hydrocele and an induration on the left epididymal head. A cytological examination of the hydrocele fluid demonstrated clusters of mesothelial cells without evidence of malignancy (class III). Left inguinal orchiectomy was performed because a 15 mm papillary pedunculated tumor was seen on the surface of the tunica vaginalis. A microscopic examination showed the papillary and glandular structures composed of cuboidal cells with no cytologic atypia, which were consistent with benign mesothelioma. The patient remains well and free of recurrent disease 10 years after operation.

Diagnosis, Differential↗
PubMed1993

Preservation of differentiated phenotypes in cultured aortic endothelial cells by malotilate and phosphoascorbic acid.

Confluent bovine aortic endothelial cells (BAECs) formed a cobblestone-shaped cell monolayer when cultured on a collagen gel in a 1:1 mixture of Dulbecco's modified Eagle's medium and Ham's-F12 supplemented with 5% newborn calf serum. Within a few days, however, they lost cell-cell attachment and became fibroblastic. When BAECs were cultured in the same culture medium but further supplemented with either 10 micrograms/ml malotilate or 1 mM phosphoascorbic acid, the monolayer organization and the cobblestone-like cell morphology were maintained for more than 2 weeks although many sprout cells were observed underneath the monolayer. In contrast, if both malotilate and phosphoascorbic acid were present in the culture medium, a tight monolayer without underlying sprout cells was maintained for at least 4 months and the cells expressed factor VIII-related antigens and massively internalized acetylated low density lipoprotein. By electron microscopy, we observed well-developed gap and adherence junctions, Golgi apparatuses and vesicles many of which were open to the outside by fusing with either the apical or the basal surface, indicating high metabolic activity of the cells cultured for weeks in the same dish. Although malotilate-treated BAEC monolayers secreted increased levels of prostacyclin (PGI2), the drug did not appear to directly affect the PGI2 production pathway since the similarly increased PGI2 production was noted in tight monolayers formed without the use of malotilate. Our results indicate that malotilate and phosphoascorbic acid together preserve differentiated phenotypes in cultured endothelial cells.

Animals↗
PubMed1993

[Idiopathic thrombocytopenic purpura (ITP) associated with renal injury: report of a case].

A 42-year-old woman with gross hematuria, left flank pain and vomit after being hit on her back admitted to our hospital. She has been under treatment for idiopathic thrombocytopenic purpura (ITP) with prednisolone for these last 14 years. Computerized tomographic (CT) scan revealed moderate laceration, subcapsular hematoma and perirenal hematoma of the left kidney. We tried treating her conservatively. The main treatment was absolute rest for two weeks, increase in the prednisolone dose and prevention from infection. On the 3rd day, the platelet count dropped to 4,000/mm3, but transfusion of platelets was not done to provide for emergency. The platelet count increased gradually and returned to normal on the 8th day. We decreased the prednisolone dose according to the platelet count. After 5 weeks, microscopic hematuria disappeared. Her clinical course was uneventful and she was discharged after 7 weeks.

Accidental Falls↗
PubMed1993

[Neutrophil chemotactic factor in supernatant from pulmonary fibroblasts stimulated with cytokines].

Fibroblasts are important for maintenance of the structural frame network for most tissues, and they also play an important role in the inflammatory process via production of various mediators. In this study, we demonstrated that pulmonary fibroblasts may participate in pulmonary inflammation by production of neutrophil chemotactic factor (NCF). Pulmonary fibroblasts were stimulated with various cytokines (IGF-1, PDGF, IL-1 alpha, IL-1 beta, IL-2, IL-6, TNF, IFNr). Fibroblasts stimulated with either TNF, IL-1 alpha or IL-beta but not IGF, PDGF, IL-2 or IL-6 demonstrated a kinetic and dose-dependent increase in NCF activity. The NCF activity of crude supernatant was heat-stable and was not changed by anti-C5 antibody treatment or ether extraction. Characterization of the NCF activity by gel-filtration using high pressure liquid chromatography showed two active fractions, one with MW greater than 100 kD and the other with MW less than 10 kD. NCF activity in the small molecular weight fraction was demonstrated by inhibition of chemotaxis by addition of anti-IL-8 antibody. These data suggest that cytokine-treated fibroblast-derived NCF may be important in the pathogenesis and expression of a variety of pulmonary disease processes associated with neutrophil accumulation and activation.

Cytokines↗
PubMed1992

A novel anti-HIV synthetic peptide, T-22 ([Tyr5,12,Lys7]-polyphemusin II).

Tachyplesin and polyphemusin are antimicrobial peptides recently isolated from the hemocytes of horseshoe crabs (Tachypleus tridentatus and Limulus polyphemus). We synthesized them and their analogs and examined their antiviral activity against human immunodeficiency virus (HIV) type 1 in vitro. The infection of human T cells with the virus was markedly inhibited by some of them at low concentrations. In this structure-activity study, we found that [Tyr5,12, Lys7]-polyphemusin II, which was designated as T22, had extremely high anti-HIV activity. Its 50% inhibitory concentration (EC50) was 0.008 micrograms/ml, while its 50% cytotoxic concentration (CC50) was 54 micrograms/ml and these values were comparable to those of AZT. This result indicates that T22 would be a potential candidate for the therapy of HIV infection.

Amino Acid Sequence↗
PubMed1992

Successful pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension associated with anticardiolipin antibodies: report of a case.

Chronic pulmonary thromboembolism with pulmonary hypertension is a rare but most unique syndrome in the broad spectrum of pulmonary embolism. This report describes a successful pulmonary thromboendarterectomy performed for a totally occluded right pulmonary artery on a 43 year old man who presented with positive cardiolipin antibodies. The surgery was performed through a median sternotomy with cardiopulmonary bypass and intermittent periods of deep hypothermic circulatory arrest. We are convinced that this method allows for complete removal of the thrombotic obstruction and should be the procedure of choice for patients with very proximal obstruction of a pulmonary artery.

Adult↗
PubMed1992

Improvement of nitrogen supply for L-threonine production by a recombinant strain of Serratia marcescens.

Serratia marcescens T-2000 was previously reported to be an L-threonine-producing strain that harbors the recombinant plasmid carrying the mutant-type threonine operon. This strain produced 55 g of L-threonine/L of the medium containing urea as a nitrogen source after 72 h of cultivation. In the urea-containing medium, transitory stop of the growth was observed during the early period of cultivation when the entire amount of ammonium ion formed from urea via heat decomposition disappeared in the medium. This indicated that the shortage of ammonium supply in cells might delay both the cell growth and the L-threonine production. The use of ammonia water as a nitrogen source for L-threonine production was therefore studied, because microbial cells generally assimilate this source more readily than urea. When ammonia water was automatically fed to the medium so as to maintain the pH of the medium at around 7, the growth was accelerated, and the L-threonine production reached a maximum of 65 g/L at 48 h. Under these conditions, sucrose, a carbon source, was continuously fed to the medium, resulting in the production of 100 g of L-threonine/L at 96 h. Thus, the L-threonine production of the recombinant L-threonine-producing strain could be increased by devising the method for supply of a nitrogen source.

Ammonia↗