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Biomedical subjects

M Fujiwara

Publications and source records attributed to M Fujiwara.

At least 757 records · Page 42Linked to original sources
PubMed1982

Irradiation of spontaneous carotid-cavernous fistulas.

Two patients with spontaneous carotid-cavernous fistulas were successfully treated with cobalt 60 irradiation to the sellar region. Angiographically, one patient showed combined-type shunts comprising a dural internal carotid-cavernous fistula and a direct internal carotid-cavernous fistula; the other patient had a mixed dural external and internal carotid-cavernous fistula. The respective total radiation dose was 3,200 rads and 3,024 rads. The patients responded satisfactorily to the treatment, with disappearance of the fistulas on angiograms and patency of the internal and external carotid arteries.

Aged↗
PubMed1982

Immunohistochemical studies on enteric substance P of extrinsic origin in the cat.

The origin of substance P (SP)-like immunoreactivity in the Auerbach's plexuses of the esophagus, stomach duodenum was examined in the cat. The intensity of the fluorescence and the area of distribution of SP-like immunoreactivity in the Auerbach's plexuses of the cardiac part of the esophagus and the corpus of the stomach were markedly reduced by bilateral ligation of the abdominal vagus nerve, while little change occurred in the antrum of the stomach and the duodenum. After splanchnic nerve ligation or celiac ganglionectomy, the SP-like immunoreactivity in the Auerbach's plexuses of the antrum of the stomach and the duodenum was markedly reduced, whereas that in the esophagus and the corpus of the stomach was only slightly attenuated. Intense SP-like immunoreactivity was observed in the portions of the abdominal vagus and splanchnic nerve cranial to the ligation. This the Auerbach's plexuses of the esophagus, stomach and duodenum were considered to contain SP transported through the vagus and splanchnic nerve. It was also indicated experimentally that the SP-like immunoreactive fibers in the auerbach's plexus arose from the nodose and spinal ganglia as well as from the dorsal vagus nucleus in the medulla oblongata.

Animals↗
PubMed1982

The random walk description for isotope exchange in a polypeptide.

Isotope exchange in a polypeptide is considered from the point of view in which the boundary point between helix and coil regions of a polypeptide behaves like a weakly asymmetric random walker. We assume that the boundary point is reflected completely at the ends of a polypeptide. The equilibrium fraction of helix region is obtained under this assumption, and this is also confirmed by computer simulation. The experimental results of isotope exchange can be explained in this situation. On the other hand. the rate constant of exchange of a residue given by experiments can also be explained by another assumption, as considered before (M. Fujiwara and N. Saitô, Polym. J. 9 (1977) 625.), in which the nucleations of coil states take place in the helix region. Which of the two is of major importance is left to further studies.

Journal Article↗
PubMed1982

Effects of goniopora toxin on non-adrenergic, non-cholinergic response and purine nucleotide release in guinea-pig taenia coli.

1. Effects of goniopora toxin (GPT) on non-adrenergic, non-cholinergic inhibitory responses were examined in isolated guinea-pig taenia coli and the transmission mechanism was analysed.2. GPT (20-50 nM) gradually augmented the relaxation and rebound contraction induced by electrical transmural stimulation in the presence of guanethidine and atropine. These effects were abolished by tetrodotoxin.3. The resting tension and the response to exogenously applied ATP were little affected by GPT.4. The action potentials and the electrotonic potentials recorded by a double sucrose-gap method were little affected by GPT.5. These results indicate that the augmentation is elicited by a direct action of GPT on the non-adrenergic, non-cholinergic neurones, rather than on the smooth muscles per se.6. GPT augmented the amplitude of the inhibitory junction potential (i.j.p.) recorded in the presence of guanethidine and atropine. GPT also enhanced the (3)H efflux in response to electrical transmural stimulation of preparations pre-loaded with [(3)H] adenosine. Tetrodotoxin markedly inhibited or abolished the i.j.p. and (3)H efflux.7. These results would suggest that augmentation of the non-adrenergic, non-cholinergic responses is due to increased transmitter release from the nerve. Under conditions in which the transmitter release was augmented, the non-adrenergic, non-cholinergic response showed an essentially similar pattern to that obtained under normal conditions; therefore the inhibitory response is probably due to a putative transmitter, possibly ATP or a related nucleotide.

Adenosine Triphosphate↗
PubMed1982

Polyclonal antibody synthesis by bone marrow cells of New Zealand black mice. I. Assessment of activity in an adoptively transferred histocompatible host.

The activity of polyclonal antibody synthesis (PAS) of bone marrow cells (BMC) was assessed by enumerating anti-trinitrophenyl (TNP) plaque-forming cells (PFC) or immunoglobulin-secreting cells (IgSC) generated in the spleen of BMC-reconstituted syngeneic or H-2-compatible hosts. BMC of NZB mice generated large numbers of anti-TNP PFC or IgSC as compared with those of C57BL/6 mice or H-2-compatible, nonautoimmune strains of mice (BALB/c, DBA/2 and B10 . D2 mice). Causes for the enhanced PAS activity were explored. Susceptibility to known B cell mitogens was examined and it was shown that spleen cells of the recipients of NZB BMC were refractory to the mitogens while PAS was apparent and acquired responsiveness after 15 days as those from nonautoimmune strains of mice. Furthermore, environmental factor(s) did not seem to be responsible for the enhanced PAS, since BMC from nonautoimmune BALB/c mice showed little PAS activity when transferred into heavily irradiated NZB mice and those of NZB mice showed enhanced PAS activity when transferred into B10 . D2 or BALB/c mice. It seems most likely that enhanced PAS activity of BMC of NZB mice is a genetically inherent phenomenon. PAS activity of BMC and spleen cells of NZB mice increased significantly with increasing age of mice.

Animals↗
PubMed1982

Polyclonal antibody synthesis by bone marrow cells of New Zealand Black mice. II. Cellular basis of PAS activity of NZB bone marrow cells.

In the preceding report, enhanced polyclonal antibody synthesis (PAS) activity of bone marrow cells (BMC) of NZB mice was shown. Cells involved in its activity among BMC population were explored in this report. Antibody-forming cells (AFC) already existing in the bone marrow were not responsible for this activity since depletion of AFC by passage through a Sephadex G-10 column did not affect the numbers of anti-TNP AFC and immunoglobulin-secreting cells (IgSC) in the spleen of BMC-reconstituted mice when assayed 7 days after the transfer. Thy-1-positive cells among BMC population and host thymus were not relevant to PAS. Suppressor cells seemed to play little role as observed in transfer of mixed BMC population from NZB and BALB/c mice. PAS activity was prominently observed in surface immunoglobulin-positive cells. Significance of enhanced PAS activity was discussed with reference to autoantibody production.

Animals↗
PubMed1982

Increased resistance to effector cell blockade in antibody-producing cells of NZB mice.

Susceptibility of B lymphocytes fo 'effector cell blockade', i.e. in vitro inactivation of antibody-forming cells by specific antigen, was studied in NZB and C57BL/6 mice. Mice were immunized either with dinitrophenylated dextran (DNP-Dex) or DNP-keyhole limpet hemocyanin (DNP-KLH). It was shown that both direct and indirect anti-DNP plaque-forming cells (PFC) from older NZB mice were less affected by the preincubation with the corresponding antigen than those from age-matched C57BL/6 mice or young NZB mice. The increased resistance of B lymphocytes in aged NZB mice to the effector cell blockade may play a significant role for generation of autoantibody-forming cells in the presence of excess amounts of corresponding antigens.

Aging↗
PubMed1982

Effects of 7-ethoxycarbonyl-6,8-dimethyl-4-hydroxymethyl-1(2H)-phthalazinone (EG626) on the spinal trigeminal nucleus, ventral posteromedial nucleus, and sensory cortex.

Effects of 7-ethoxycarbonyl-6,8-dimethyl-4-hydroxymethyl-1 (2H)-phthalazinone (EG626) on the spinal trigeminal nucleus (STN), ventral posteromedial nucleus (VPM), and sensory cortex were examined in cats anesthetized with alpha-chloralose in comparison with the effects of morphine. EG626 produced a dose-dependent inhibition of the polysynaptic components of the cortical field potentials upon VPM stimulation and either facilitatory or inhibitory effects on the polysynaptic components of the VPM field potential upon stimulation of the medial lemniscus, while the drug failed to affect the STN field potential with trigeminal nerve stimulation. Morphine inhibited the postsynaptic components of the STN field potentials and to a lesser extent, the polysynaptic components of the cortical field potential; and the effects of morphine on the VPM field potential were similar to those seen with EG626. Pretreatment of the animal with naloxone antagonized the facilitatory effect on the VPM field potentials produced by morphine, but not those by EG626. Morphine and EG626 induced either a prolonged increase in the blood flow or transient increase followed by a decrease in the blood flow in the VPM. These results suggest that EG626 may impair the polysynaptic transmission and/or neuron excitability in the sensory cortex and the VPM at least partly due to the change in blood flow there as does morphine. Unlike morphine, however, EG626 did not produce any obvious effect on the STN.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1982

The activities of noradrenergic and dopaminergic neuron systems in experimental hydrocephalus.

Experimental hydrocephalus was induced in rabbits by intracisternal injection of kaolin suspension, and the concentration of noradrenaline (NA), dopamine (DA), and their metabolites was determined in several brain regions. The NA concentration had decreased in the cerebellum, hypothalamus, and pons plus medulla oblongata, and increased in the caudate nucleus at 2 days after kaolin injection (the stage of early intracranial hypertension). At 1 week (the stage of progressive hydrocephalus), the NA content had returned to control levels in all brain regions studied, and it decreased again at 4 weeks (the stage of chronic hydrocephalus) in the pons plus medulla oblongata. The DA level was unchanged throughout the 4-week period after kaolin injection. The concentration of 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MOPEG-SO4), the major metabolite of NA, was elevated in all brian regions except the caudate nucleus at all stages after kaolin injection. An increase in MOPEG-SO4 in the caudate nucleus was also observed 1 week after kaolin injection. The content of homovanillic acid (HVA), the major metabolite of DA in the rabbit brain, was decreased in the cerebral cortex at 2 days and at 1 week after kaolin injection, and in the caudate nucleus at 2 days and at 1 week, and 4 weeks. The level of HVA was increased in the hypothalamus at 2 days, in the cerebellum at 2 days and at 1 week, in the pons plus medulla oblongata at 2 days, 1 week, and 4 weeks, and in the midbrain at 4 weeks. These data suggest that, in experimental hydrocephalus in the rabbit, NA release is increased throughout the brain, while DA release is decreased in the cerebral cortex and caudate nucleus, and increased in the cerebellum, hypothalamus, midbrain, and pons plus medulla oblongata.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1982

Cooperative role of T lymphocytes and macrophages in anti-tumor activity of mice pretreated with schizophyllan (SPG).

Anti-tumor activity was studied in mice injected with Schizophyllan (SPG), a glucan produced by Schizophyllum commune Fries. SPG-injected mice rejected subcutaneously inoculated sarcoma-180 and the anti-tumor activity was shown to be mediated by host spleen and lymph node cells. The anti-tumor activity lasted as long as 60 days after the SPG administration as assessed by transfer of cells into normal recipients. Cells involved in anti-tumor activity were shown to be T lymphocytes since anti-tumor activity was diminished when lymph node cells from SPG-treated mice were treated with anti-Thy-1.2 sera plus complement, whereas cells passed through a nylon wool column retained the activity. Macrophages were also shown to be involved since administration of carrageenan or trypan blue into the host decreased the inhibition ratio of tumor growth. It was concluded that anti-tumor activity in SPG-treated mice was mediated by the cooperation of T lymphocytes and macrophages, thus the impairment of either function decreased anti-tumor activity.

Animals↗
PubMed1982

Resistant nature of T cells of autoimmune mice to tolerance induction with human serum albumin.

Inducibility of immunological tolerance to a T-dependent antigen, human serum albumin, was studied in autoimmune mice (NZB, MRL/Mp-lpr/lpr and male BXSB mice), comparing with non-autoimmune mice (BALB/c, DBA/2, MRL/Mp-+/+ and female BXSB mice). Weekly injections of increasing doses of the tolerogen into DBA/2 mice induced T-cell tolerance without the participation of suppressor cells and without affecting B cells. All of the autoimmune mice tested were refractory to the tolerogen; partial tolerance (40%-60% responsiveness) was attained in mice aged 1 month, but not in older mice. By comparison, tolerance was induced in non-autoimmune mice to a similar degree irrespective of the age of the mice. The tolerance inducibility was also examined in reciprocal bone marrow cell (BMC) transfer experiments between NZB and DBA/2 mice and also BMC transfer into B10-D2 mice. It was shown that recipients of NZB BMC were more resistant to tolerance induction than those of DBA/2 BMC, while irradiated NZB mice receiving DBA/2 BMC were susceptible. Hence, it is suggested that the tolerance-resistant nature of the NZB mice was inherent in T-cell precursors in the bone marrow and not in the host environment. Similar findings in support of this notion were also observed in BSXB mice. The significance of tolerance resistance in the development of autoimmunity is discussed.

Animals↗
PubMed1982

[Therapeutic results of DCMP therapy (2M-80) in acute non-lymphocytic leukemia--the relationship between the residual leukemic cells and duration of remission].

In this study the duration of complete remission by daunomycin, cytosine arabinoside (Ara-C), 6MP and prednisolone (DCMP) therapy using a large dose of Ara-C (200 mg) (protocol 2M-80) was compared with that of DCMP therapy with a low dose of Ara-C (80-160 mg) in acute non-lymphocytic leukemia (ANLL). In protocol 2M-80, the chemotherapy was continued until leukemic blasts in marrow were attained below 3%. Complete remission was induced in about 80% of ANLL patients in both chemotherapies. However, the duration of remission in protocol 2M-80 appeared to be much longer than that of DCMP therapy with a low, dose of Ara-C. This difference was dependent not on the consolidation and maintenance therapy, but on the total dose of Ara-C used and leukemic blasts left in marrow at the end of chemotherapy. This suggests that it is important to reduce leukemic blasts in marrow as low as possible by induction chemotherapy to obtain a long-term remission in ANLL.

Acute Disease↗
PubMed1982

A new method for colony formation in vitro by leukemic cells in acute nonlymphocytic leukemia with PHA-stimulated lymphocyte conditioned medium as stimulating factor.

A new agar culture system to clone specifically acute nonlymphocytic leukemia (ANLL) is described, which consists of two phases: an initial liquid phase in the presence of PHA-stimulated lymphocyte conditioned medium (PHA-LCM) and a semi-solid phase. By preincubation of leukemic cells with PHA-LCM in a liquid phase, leukemic cells were found to be more sensitive to forming colonies and clusters in agar medium. In addition, this PHA-two step assay could eliminate colony formation by T cell progenitors. The leukemic origin of the colonies was proven by electron-microscopic analysis, which demonstrated the presence of nuclear blebs and abnormal perinuclear fibril formation. Morphological studies also indicated myeloid differentiation of the cells in the leukemic colonies, although considerable variation was observed among patients. The wide range of linearity between the number of cells plated and the number of colonies grown permits quantitative assay of colony-forming leukemic cells (L-CFU). This assay should be valuable for studies of chemotherapy, growth regulation, and differentiation of L-CFU.

Acute Disease↗