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M Tamura

Publications and source records attributed to M Tamura.

At least 433 records · Page 24Linked to original sources
PubMed1995

NS-3(CG3703), a TRH analog, ameliorates scopolamine-induced memory disruption in rats.

The effects of a metabolically stable TRH analog, N-[[(3R, 6R)-6-methyl-5-oxo-3-thiomorpholinyl]carbonyl]-L-histidyl-L- prolinamide tetrahydrate (NS-3, CG3703) on the scopolamine-induced memory disruption in maze performance tests were investigated in rats. a) In the delayed nonmatching-to-sample (DNMS) task using a T-maze, NS-3 (0.3 mg/kg) produced a significant reversal of the marginal disruption of choice accuracy induced by scopolamine (0.3 mg/kg) at the short (5 s) and long (120, 480 s) interval delays. Physostigmine (0.5 mg/kg) produced a significant reversal only at a 5-s interval delay. b) In the eight-arm radial maze task, NS-3 (0.3 mg/kg) significantly reversed the deficit of choice accuracy induced by scopolamine (0.3 mg/kg), whereas neither TRH (3-30 mg/kg) nor physostigmine (0.1-1 mg/kg) had any effect. The consistent reversal of these maze-learning performances by NS-3, but not by TRH or physostigmine, may be due to its potent enhancement of cholinergic and noradrenergic neuronal activities.

Animals↗
PubMed1995

Effect of MDP-Lys(L18), a derivative of MDP, on enhancing host resistance against Hantaan virus infection in newborn mice.

We examined the effect of MDP-Lys(L18), a lipophilic derivative of muramyl dipeptide, on the enhancement of host resistance against virus infection in newborn mice. Newborn mice were inoculated with 4 LD50/mouse of Hantaan virus strain 76-118 (HTN) one day after birth. Mice given 100 micrograms/mouse of MDP-Lys(L18) before infection exhibited significantly higher survival rates than those of non-treated mice. The effect of MDP-Lys(L18) was also restorative when given to the mice 4 or 7 days after infection. The titers of virus isolated from the lungs and spleens 12 days after infection, were about 30-times lower in MDP-Lys(L18)-treated (lung: 1.0 x 10(3) FFU; spleen: 6.8 x 10(1) FFU/mouse), than those of non-treated mice (lung: 3.4 x 10(4) FFU; spleen: 1.9 x 10(3) FFU/mouse). Furthermore, the virus was undetectable in the brains of MDP-Lys(L18)-treated mice, whereas viruses were isolated from 3 of 6 non-treated mice. MDP-Lys(L18) augmented the number of peripheral leukocytes and splenocytes, as well as mitogenic responses of the cells from bone marrow and spleen of newborn mice. These results suggest that MDP-Lys(L18) enhanced the resistance of newborn mice against HTN virus in a systemic infection model, and that this mechanism is involved in the enhancement of hematopoiesis and responsiveness of immune-related cells to mitogens.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1995

Effects of muramyl dipeptide derivatives as adjuvants on the induction of antibody response to recombinant hepatitis B surface antigen.

The ability of two muramyl dipeptide (MDP) derivatives, B30-MDP and MDP-Lys(L18), to enhance the immunogenicity of recombinant hepatitis B surface antigen (rHBsAg) was examined. When mice were immunized intraperitoneally with rHBsAg together with each MDP derivative, the antibody titres were higher than those in mice immunized with alum-adsorbed rHBsAg, which is a commercially available hepatitis B vaccine. When mice were given a subcutaneous or intramuscular injection of rHBsAg and either MDP derivative, the antibody titres were the same as those in mice given alum-adsorbed rHBsAg. These results indicate the usefulness of MDP derivatives as immunoadjuvants for a new-generation vaccine.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1995

Region-dependent asymmetrical or symmetrical variations in the oxygenation and hemodynamics of the brain due to different mental stimuli.

The present paper demonstrates region-dependent variations in the oxygenation and hemodynamics of the brain hemispheres due to three different types of mental stimulation. The variations were observed with a four-channel optical imaging system using tissue-transparent near-infrared light and described changes from baseline of both the hemoglobin oxygenation state and blood volume during three kinds of psychological or mental tasks. During the mirror drawing task, a lateralized hemisphere response (the dominant hemisphere response pattern) was observed in 57% of 14 right handed volunteers in the frontal region (Brodmann's area 10), while in the temporal region (area 38), 80% showed the bilateral response pattern. A large majority of the subjects showed the bilateral response pattern in the frontal and temporal regions while calculating. A smaller majority showed this while looking at anatomical charts, though 30% did not show any response at all in the temporal region. This showed that there were region-dependent asymmetrical or symmetrical variations of the oxygen delivery-oxygen utilization relationship due to different types of mental stimuli.

Adult↗
PubMed1995

Expression of epidermal growth factors and epidermal growth factor receptor in normal cycling human ovaries.

Immunolocalization of transforming growth factor-alpha (TGF alpha), epidermal growth factor (EGF), cripto-1, amphiregulin and epidermal growth factor receptor (EGFR) was studied in 51 premenopausal human ovaries at various phases of the menstrual cycle. Localization of mRNA for TGF alpha and EGF was also studied by in-situ hybridization. Immunoreactive TGF alpha was observed predominantly in theca cells in 12 of 33 antral follicles in the follicular phase (6/14 dominant follicles, and 6/19 non-dominant) but not in any of the 18 follicles in the luteal phase or in primordial and pre-antral follicles. TGF alpha immunoreactivity was present predominantly in the luteinized granulosa cells in 13 of 15 corpora lutea in the luteal phase, which are considered to be active in steroidogenesis, but not in any of the regressed corpora lutea. Accumulation of TGF alpha mRNA hybridization signal was observed only in the theca cells in the follicles and luteinized theca cells in the ovaries that were immunohistochemically positive for TGF alpha. EGFR immunoreactivity was detected in 24 of 33 antral follicles in the follicular phase and in two of 18 follicles in the luteal phase but not in any of the corpora lutea. Immunoreactive EGF, cripto-1 and amphiregulin or EGF mRNA was not detected in any follicles, corpora lutea, or the stroma cells examined. These results indicate that, of the epidermal growth factors examined in this study, TGF alpha is locally synthesized in normal cycling human ovaries and TGF alpha may be synthesized in theca cells and act on the granulosa cells in a paracrine fashion through the EGFR in ovarian follicles.

Adult↗
PubMed1995

Some characteristics of the fluorescence lifetime of reduced pyridine nucleotides in isolated mitochondria, isolated hepatocytes, and perfused rat liver in situ.

By extensively examining the experimental conditions for time-resolved spectrophotometry of non-transparent light scattering systems, we demonstrated the feasibility of quantitative analysis of both the fluorescence lifetime and intensity of reduced pyridine nucleotides in living tissues, suspensions of isolated liver mitochondria, and hepatocytes, as well as hemoglobin-free perfused rat liver being used systematically for measurements. The fluorescence decay was analyzed by the maximum likelihood method with a 4-component decay model. The lifetime of NADH observed in mitochondria (mean: 2.8 +/- 0.2 ns) was much longer than that of the free form in an aqueous solution (mean: 0.43 +/- 0.01 ns), and it was characterized as a protein-bound form. The lifetime was not affected by either aerobic or anaerobic conditions nor by the energy state, though the intensity changed markedly. The decay curves of isolated hepatocytes under normal aerobic conditions were the same as those of isolated mitochondria, though cytosolic NADH and NADPH were superimposed. Under the conditions of "unphysiological" acidosis, the mean lifetime became about 1.5 times longer than that under normal conditions. With perfused liver, the relative contributions of cytosolic NADH and NADPH were determined by infusing lactate and tert-butylhydroperoxide. Cytosolic NADH did not contribute to the overall fluorescence of pyridine nucleotides. In contrast, about 70% of the total fluorescence intensity was due to cytosolic NADPH, but its decay parameters were essentially the same as those of mitochondrial NADH. No free form of either NADH or NADPH was detected in the cytosolic and mitochondrial spaces. We concluded that the changes in fluorescence intensity observed under the various conditions can be simply explained by a change in the amount of reduced pyridine nucleotides in tissues, rather than by changes in the microscopic environment. The wide applicability of time-resolved fluorescence photometry to in vivo studies is well documented.

Aerobiosis↗
PubMed1995

Coexistence of nitric oxide synthase, tyrosine hydroxylase and vasoactive intestinal polypeptide in human penile tissue--a triple histochemical and immunohistochemical study.

Recently, nitric oxide (NO) has been believed to act as a neuronal messenger to mediate penile erection. In the present study using human penile tissue, we investigated the coexistence of neuronal NO synthase (NOS), tyrosine hydroxylase (TH) and vasoactive intestinal polypeptide (VIP) by a triple staining method using NADPH diaphorase (ND) staining, a specific histochemical marker of neuronal NOS, and immunohistochemical staining for TH and VIP. Numerous ND-positive nerve fibers and TH-containing fibers were seen in axon bundles, but their distributions were different. Only a few axons in the bundles showed VIP immunoreactivity. Abundant fine varicose nerve terminals innervating cavernous smooth muscles and deep and helicine arteries were observed. The proportion of fibers showing TH-immunoreactivity in ND-positive terminals in the cavernous space was about 25%, and that of VIP was about 40%. Vasoactive intestinal polypeptide may act as a coworker in these fibers both in cavernous trabeculae and around arteries, as about 40% of NOS-containing fibers also showed VIP immunoreactivity. The physiological significance of the colocalization of TH and NOS is unclear, and further studies are required to know the physiological significance of the colocalization of NOS and other neurotransmitters in penile tissue.

Amino Acid Oxidoreductases↗
PubMed1995

Infectious retrovirus is inactivated by serum but not by cerebrospinal fluid or fluid from tumor bed in patients with malignant glioma.

Intravenous gene transfer using recombinant retroviruses tends to suffer from a low infectious viral titer when conducted in vivo. This is, in part, caused by complement-mediated proteolytic inactivation of the retrovirus in human serum. However, if the retroviruses were directly injected into the brain, they might not be inactivated. Supernatant from amphotropic retrovirus-producing cells harboring the BAG vectors was incubated with sera or cerebrospinal fluid (CSF) of patients with gliomas or unrelated disorders. The retroviruses were severely inactivated in sera. However, no such inactivation was noted in CSF or fluid from the tumor bed of glioma patients. These data suggest that gene transfer using recombinant retroviruses could be done into the cavity after removal of the tumor in glioma patients.

3T3 Cells↗
PubMed1995

[Study on azithromycin in treatment of diffuse panbronchiolitis].

In the treatment of diffuse panbronchiolitis, azithromycin (AZM), a new macrolide antibiotic with 15-membered lactone ring, was studied for its efficacy and safety. AZM, 250 mg, was intermittently administered to a total of 60 patients twice a weeks, for 3 months as a rule, and its efficacy was clinically evaluated in 52 patients and the safety in 55. The rate of efficacy was 84.6% (44/52). Clinical findings 12 weeks after the start of administration showed a decrease in sputum volume in 30 of 46 patients and amelioration of dyspnea on exertion in 23 of 46 patients, and no worsening of symptoms was observed in the patients. Vital capacity (4/22), FEV1.0 (6/21), cold agglutination reaction (22/28), and CRP (16/36) were also improved. The rate of eradication of organisms isolated from the sputum except for indigenous organisms was 39.5% (15/38); 4 of the 22 strains of Pseudomonas aeruginosa were eradicated. Adverse reactions were observed in 4 of the 55 patients (7.3%), 1 patient each with rash, itching, diarrhea, and a gastric symptom (heavy feeling in the stomach). 4 of the 54 patients (7.4%) exhibited abnormal changes in clinical laboratory test values values. These were an increase in eosinophil count in 2, elevation of GOT in 1, and elevation of Al-P in 1. These adverse reactions and abnormal changes in laboratory tests were mild or moderate. Therefore, long-term intermittent administration of AZM, twice a week, is expected to have the same effect in the treatment of diffuse panbronchiolitis as long-term small-dose administration of 14-membered macrolides such as erythromycin and clarithromycin, whose effects have already been established.

Adolescent↗
PubMed1995

Abrupt aggravation of atrioventricular block and syncope in hypertrophic cardiomyopathy.

A 10 year old girl with hypertrophic cardiomyopathy (HCM) developed high grade atrioventricular (A-V) block unexpectedly, which instantly led to syncope; she required a permanent pacemaker. High grade A-V block, a rare complication of HCM, relates closely to syncope or sudden death in this disease and if progressive the use of cardiac pacing should be considered without delay.

Cardiac Pacing, Artificial↗
PubMed1995

Application of nasal continuous positive airway pressure to early extubation in very low birthweight infants.

Using a preset protocol for early extubation, 50 babies were randomly selected to post-extubation headbox or post-extubation nasal continuous positive airway pressure (N-CPAP). All infants weighed less than 1500 g, had a gestational age of less than 34 weeks, and had been weaning from mechanical ventilation within seven days of life. The criteria for extubation included stable condition, fraction of inspired oxygen (FIO2) of < or = 35%, peak inspiratory pressure (PIP) of < or = 15 cm H2O (1.47 kPa), and ventilator rate of 6/minute. Before extubation, a loading dose of aminophylline was given followed by maintenance treatment. If reintubation was not required within 72 hours of the initial extubation the procedure was considered successful. The reintubation criteria included FIO2 > or = 70% to maintain arterial oxygen tension (PaO2) of > or = 50 mm Hg (6.67 kPa) or pulse oximetry between 90-96% and pH of < 7.25, and arterial carbon dioxide tension (PACO2) of > 60 mm Hg (8.00 kPa) and severe or recurring apnoea. The overall success rate of early extubation was 66% (33/50). The individual successful extubation rate of post-extubation in the N-CPAP group and the post-extubation headbox group were 84% (21/25) and 48% (12/25), respectively (p = 0.017; chi 2). There were no significant differences in clinical characteristics between the two groups. The most common cause of failure in early extubation was apnoea, and most occurred in the headbox group (9/12). These results suggest that application of N-CPAP to a preset protocol for extubation can achieve a better success rate of early extubation in very low birthweight (VLBW) infants.

Clinical Protocols↗
PubMed1995

Occupational hypersensitivity pneumonitis in Japan: data on a nationwide epidemiological study.

OBJECTIVES: Diagnostic criteria were prepared for hypersensitivity pneumonitis (HP) and a nationwide survey was conducted to investigate epidemiological and clinical characteristics of HP in Japan. The results are presented with special focus on occupational HP and on the key to the diagnosis of HP. METHODS: A questionnaire was completed by 185 doctors from 185 hospitals (response rate 89.5%). All cases were verified according to diagnostic criteria; 835 cases were classified as HP (653 definite and 182 probable). These 835 cases (total HP) and 99 possible cases of HP diagnosed during the 1980s were analysed and presented as a case series study. RESULTS: Occupational HP was noted in 115 cases (13.8%). 21 occupations, and 20 aetiological antigens were listed. Farmer's lung: 68 cases (59% of occupational HP) was the most prevalent diagnosis followed by 19 industrial workers who handled chemicals (for example, isocyanate) and 10 office workers. Unique cases of mushroom, greenhouse, and silkworm farmers, and a new type of bagassosis are also described. Adverse environmental conditions, immunological findings on examination, antigen challenge, and pathological findings were all significantly lower for possible than for total HP. This was not true for clinical findings. The differences in antibody analysis (6% positive of possible HP v 59% of total HP) and environmental challenge (3% v 74%) were notable. CONCLUSION: These data suggest that a careful interview about the environment and an antigen panel matched to variations in exposure are the key to the diagnosis.

Alveolitis, Extrinsic Allergic↗
PubMed1995

Adhesion of calcium oxalate crystals to Madin-Darby canine kidney cells and some effects of glycosaminoglycans or cell injuries.

The present investigation studied the quantitative adhesion of calcium oxalate monohydrate (COM) crystals to the surface of Madin-Darby canine kidney cells, which exhibit many characteristics of renal cortical collecting tubule cells. COM crystals adhered to the cell surface, and the attachment showed a time and concentration dependency with plateau. The results suggested that the attachment of microcrystals to the cortical tubular cell might be one of the earliest processes in the formation of kidney stones. Pretreatment with glycosaminoglycans significantly reduced the adherent crystals. Injuries to the Madin-Darby cells induced by 0.1 M HCl and gentamicin resulted in significant decreases of COM crystal adhesion to the cell surface. It was suggested that urinary glycosaminoglycans might play some critical role in preventing crystal adhesion to these cellular membranes and that cell injuries might not be essential for the attachment of microcrystals to the tubular cells.

Animals↗
PubMed1995

Stimulation of endosteal bone formation by systemic injections of recombinant basic fibroblast growth factor in rats.

In vivo effects of basic fibroblast growth factor (bFGF) on bone formation was examined in rats. Daily systemic injections of 100 micrograms/kg bFGF for 7 days caused a marked stimulation of endosteal bone formation in both cortical and secondary cancellous bone areas. Histological examinations revealed that the sequence of responses to the injections of bFGF consisted of three phases: an early increase in the number of preosteoblastic cells over the osteoblastic cell layer (days 1-3), recruitment of osteoblasts from preosteoblastic cells (days 3-5), and an increase in new bone formation (days 5-7). These histological changes in the endosteum correlated closely with histomorphometrical parameters of bone formation, and the endosteal mineral apposition rate was almost unaffected during the initial 4 days but was markedly enhanced after this period. Immunohistochemical examinations using antitransforming growth factor (TGF)-beta 1 antibody demonstrated that immunostaining of preosteoblastic cells for TGF-beta already increased 1 day after bFGF treatment. Distribution of TGF-beta in osteoblasts and bone matrices began to increase on day 3, and all the osteoblasts and new bone matrices were intensively immuno-stained on day 7. These results demonstrate that systemic injections of bFGF in rats stimulate endosteal bone formation, and that the stimulation of bone formation is preceded by an initial increase in preosteoblastic cells with later recruitment of osteoblasts from these cells. Because the distribution of TGF-beta in the endosteal cells is increased by bFGF, the effect of bFGF may at least in part be mediated by TGF-beta. However, the precise mechanism of action of bFGF on bone formation remains to be clarified.

Animals↗
PubMed1995

Establishment and characterization of bone marrow stromal cell lines that support osteoclastogenesis.

We established bone marrow stromal cell lines that support tartrate-resistant acid phosphatase-positive multinucleated cell [TRAcP(+)MNC] formation by using transgenic mice harboring simian virus 40 large T antigen gene. The morphology of these TM cell lines (large T-immortalized marrow cells) was spindle-like at sparse cell density, whereas it became smaller and cuboidal at confluence. The TM cell lines showed diverse ranges of activity in supporting TRAcP(+)MNC formation when they were examined in the cocultures with spleen cells in the presence of 1 alpha,25-dihydroxyvitamin D3. Among these cell lines, TM8 supported the TRAcP(+)MNC formation most efficiently (from 400-1500 cells/well) when cocultured with spleen cells. Another bone marrow-derived cell line, TM5, supported TRAcP(+)MNC formation in the coculture assay, whereas the efficiency was approximately one fifth that of TM8. Interestingly, TM8 cells also supported TRAcP(+)MNC formation even in the cocultures at low serum concentration (0.5% fetal bovine serum) with an efficiency yielding over 200 TRAcP(+)MNCs/well. TM8 cells expressed certain levels of macrophage colony-stimulating factor and stem cell factor messenger RNAs (mRNAs), but low levels of c-fms mRNA. Expression of c-kit mRNA in TM5 and TM8 cells was undetectable. 1 alpha,25-Dihydroxyvitamin D3 treatment enhanced the expression of osteopontin mRNA more than 10-fold in these cells, indicating the presence of the receptor for this steroid. These TRAcP(+)MNCs, which developed in the cocultures of the TM8 and spleen cells, formed pits when cultured on bone slices, indicating that they were capable of resorbing bone. The various levels of expression of these genes and the difference in the supporting activities for the TRAcP(+)MNC development in the diverse TM cell lines suggest the heterogeneity in the marrow cell populations in vivo regarding their activity in supporting osteoclastogenesis.

Acid Phosphatase↗
PubMed1995

Immunohistochemical localization of Ad4-binding protein with correlation to steroidogenic enzyme expression in cycling human ovaries and sex cord stromal tumors.

Ad4-binding protein (Ad4BP) has been demonstrated recently as a transcription factor that serves as a general regulator of all steroidogenic P450 genes. We examined the expression of Ad4BP in 32 normal cycling human ovaries and 22 human ovarian sex cord stromal tumors by immunoblotting and immunohistochemistry. Immunoblotting of normal cycling human ovaries revealed a single band of 53 kilodaltons, corresponding to the mol wt of Ad4BP. We also correlated Ad4BP expression with the immunolocalization of the steroidogenic enzymes (side-chain cleavage cytochrome P450, cytochrome P450 17 alpha-hydroxylase, and cytochrome P450 aromatase). Ad4BP immunoreactivity, which was present only in the nuclei, was observed sporadically in the granulosa cells and adjacent stromal cells in the preantral follicles. In the dominant antral follicles, Ad4BP was detected in both granulosa and theca interna cells. However, in the nondominant antral follicles, Ad4BP was observed only in theca interna cells. In the corpus luteum, Ad4BP was present in both luteinized granulosa and thecal cells. Ad4BP was also expressed in some atretic follicles and degenerating corpora lutea. The spatial and temporal localization of Ad4BP in the normal cycling human ovary generally correlated well with that of steroidogenic enzymes. However, expression of the steroidogenic enzymes followed that of Ad4BP during the developing stages of the preantral follicle and vice versa during the process of follicular atresia. In ovarian sex cord stromal tumors, Ad4BP expression was observed in tumor cells that were positive for steroidogenic enzymes, but not in nonsteroidogenic tumor cells. These results, especially the in situ colocalization of Ad4BP and the steroidogenic enzymes, suggest that Ad4BP has the potential to control steroidogenic P450 expression in both normal and pathological human ovaries.

Adult↗
PubMed1995

A simplified general method for determination of recombinant retrovirus titers.

To construct recombinant retroviruses with only a single active promoter, we introduced point mutations into the TATA box region of the 3'-LTR, and successfully obtained high-titer virus with sufficient self-inactivating activity. However, the viral titer could not be determined by the number of G418 resistant colonies since the neomycin resistance gene was under 5'-LTR control, because of inactivation of the selection marker in target glioma cells. To overcome this problem, we constructed PCR primers with homology to a gene under the control of the internal promoter of recombinant retrovirus, and to retrovirus-specific sequences. There was good correlation between the amount of PCR-amplified product and the number of colony forming units when glioma cells were transduced with the retroviruses containing both the neomycin resistance gene and the HTK gene. Amplified PCR products quantitated by densitometry after glioma cells were transduced with SIV retrovirus vectors, and there was good correlation between density and sensitivity to GCV following transduction. Therefore, detection of HTK PCR products from glioma cells transduced with HTK-bearing retroviruses is useful for determining the appropriate packaging cell for efficient production of viral particles. This detection system is especially useful for isolating high titer clones producing SIV-type retroviruses.

Base Sequence↗