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M Inagaki

Publications and source records attributed to M Inagaki.

At least 325 records · Page 18Linked to original sources
PubMed1989

Domain- and sequence-specific phosphorylation of vimentin induces disassembly of the filament structure.

We reported that stoichiometric phosphorylation by either cAMP-dependent protein kinase or protein kinase C induces disassembly of vimentin filaments [Inagaki, M., Nishi, Y., Nishizawa, K., Matsuyama, M., & Sato, C. (1987) Nature 328, 649-652; Inagaki, M., Gonda, Y., Matsuyama, M., Nishizawa, K., Nishi, Y., & Sato, C. (1988) J. Biol. Chem. 263, 5970-5978]. In the present work, we attempted to identify the sites of vimentin phosphorylated by each protein kinase. Sequential analysis of the purified phosphopeptides, together with the known primary sequence, revealed that Ser-8, Ser-9, Ser-20, Ser-25, Ser-33, and Ser-41 were specifically phosphorylated by protein kinase C, whereas Ser-46 was phosphorylated preferentially by cAMP-dependent protein kinase. Both kinases reacted with Ser-6, Ser-24, Ser-38, Ser-50, and Ser-65. Specific phosphorylation sites for protein kinase C are mostly located close to the amino-terminal side of arginine while those for cAMP-dependent protein kinase are located close to the carboxyl-terminal side of arginine. The phosphorylation sites exclusively occur in the amino-terminal non-alpha-helical head domain, particularly at the beta-turn region. These results provide clues to the molecular mechanisms of phosphorylation-dependent disassembly of vimentin filaments.

Amino Acid Sequence↗
PubMed1989

An electrophysiologically defined trigemino-reticulo-facial pathway related to the blink reflex in the cat.

This study examines the direct projection of neurons in the pontomedullary reticular formation (RF) to the dorsal division of the facial nucleus (FN), where the orbicularis oculi motoneuron pool is located, and the nature of synaptic inputs to the RF neurons from the supraorbital branch of the trigeminal nerve (SON), using electrophysiological techniques in anesthetized cats. A large number of the RF neurons directly projected to the ipsilateral FN dorsal division, and some of these neurons issued axon branches probably terminating on motoneurons in the division. Many of the RF neurons projecting to the dorsal division were synaptically activated by ipsilateral SON stimulation. Most latencies of their activation were between the latencies of the early and late blink reflex responses, and the remaining latencies were shorter than those of the early response. These results suggest that the RF neurons mediate both the early and the late blink reflex responses, but mainly the late response, as premotor relay neurons.

Action Potentials↗
PubMed1989

Activated partial thromboplastin time-protamine dose relation in the presence and absence of heparin.

A protamine titration is one of the methods to determine the protamine dose necessary to neutralize heparin. The protamine dose response was studied with the activated partial thromboplastin time (APTT) in the presence of a known amount of heparin and in the absence of heparin, using freshly prepared human plasma. When heparin was present in the plasma, APTT values plateaued between a minimal neutralizing dose of protamine and a protamine dose five times greater. At doses above the APTT plateau, protamine exerted its own anticoagulant action as evidenced by an increase in APTT values. In the absence of heparin, APTT did not change until the protamine concentration reached 50 micrograms/mL. Then the APTT began to increase above this critical concentration. The increases in APTT values caused by an increase of 50 micrograms/mL of protamine were significantly greater without heparin than they were in the presence of heparin. These results suggest that protamine has a wide safety range when neutralizing heparin without exerting its own anticoagulant action. Although the mechanisms are under speculation, the heparin-protamine complex may inhibit the anticoagulant action of protamine in vitro.

Blood Coagulation↗
PubMed1989

Induction of antiidiotypic antibodies by donor-specific blood transfusions. Establishment of a human-mouse hybridoma secreting the MLR-inhibiting factor.

We describe a patient transfused with 200 ml of donor fresh whole blood three times at 2-week intervals. Three weeks after the last transfusion, transplantation and splenectomy were done at the same time. Splenic cells from this DST pretreated patient were fused with murine myeloma cells (X63-Ag8, 653). With DST pretreatment, various clones were developed in vivo, and finally 69 human immunoglobulin-secreting clones were obtained. Modulation of the alloantigen-specific MLR by supernatants from 69 clones showed various degrees of suppression or augmentation. The hybridoma clone 7 and clone 2, which had been secreting IgG antibody for more than 6 months, showed some degree of suppression in the alloantigen-specific MLR (mean suppression = 63%, 46% respectively). According to the result of MLR, clone 7 antibody was directed against recipient lymphocytes and clone 2 antibody was against donor lymphocytes. Immunoprecipitation was carried out by clone 7-IgG and clone 2-IgG. Clone 7-IgG specifically precipitated 1 molecule from the recipient lymphocyte with a molecular weight of 120 KD, similar to the molecular weight range reported for T cell receptors. Clone 2-IgG precipitated a 20 KD molecule from the donor lymphocyte. The data suggest that DST induces antibodies directed against the blood donor alloantigen-specific receptors on the recipient's T lymphocytes--and, at the same time, induces antibodies against donor lymphocyte antigens. These antibodies may be essential to prolongation of kidney allograft survival following DST.

Blood Transfusion↗
PubMed1989

[A case of secretory carcinoma of the breast in a elderly Japanese woman].

We report a case of a secretory carcinoma of the breast in a 72-year-old woman with a long history of a left breast mass. Rapid growth and skin invasion of the tumor was noticed three months before a radical mastectomy was performed and a lung metastasis was found one month after the operation. A metastasis to the axillary nodes was noted in 6 of 9 resected specimens and a receptor assay of the estrogen and progesterone proved to be negative. This patient is the oldest case of a secretory carcinoma of the breast reported in Japan.

Adenocarcinoma↗
PubMed1989

[Fluconazole treatment of systemic mycoses].

Efficacies of fluconazole, a new triazole antifungal agent, were evaluated in 11 cases of systemic mycoses (1 case each of candiduria, pulmonary cryptococcosis, pulmonary aspergillosis, pulmonary penicilliosis and suspected fungal pulmonary infection, and 3 cases each of candidemia and Candida endophthalmitis). The clinical efficacies were excellent or good in 8 out of 9 cases and poor in 1. Side effects observed were mild with 1 incident each of gastrointestinal symptom and reversible leukopenia. This drug appears to be promising in treatment of systemic mycoses.

Adolescent↗
PubMed1989

[Pacemaker catheter induced systolic murmurs in two patients].

Although extracardiac sounds secondary to cardiac pacing have been well known, the murmurs originating in the heart after permanent pacemaker implantation and then disappearance after exchanging a temporary to permanent lead have rarely been reported. In this paper, two patients revealing a musical systolic murmur after placement of a transvenous endocardial pacemaker in the absence of any complications were documented. Case 1: A 43-year-old man with episodes of dizziness and brady-tachycardiac atrial fibrillation. Immediately after the implantation of a temporary transvenous right ventricular pacemaker, a high-pitched systolic musical murmur was heard at the lower left sternal border. No murmur was however gullible after a permanent pacemaker implantation in this case. Case 2 was a 83-year-old female with coronary heart disease associated with sick sinus syndrome to whom a permanent transvenous right ventricular pacemaker was inserted. A musical systolic murmur occurring immediately after the procedure was best audible at the apex. Although numerous papers concerning the mechanisms of these cardiac murmurs have been reported without reaching conclusive explanations, our data based on two cases examined with Doppler echocardiography did not support the idea of tricuspid regurgitation as one of causative factors. In the first case, this murmur appeared only a temporary pacing was performed and disappeared after implantation of a permanent pacemaker lead. On the contrary, however, the 2nd case revealed after the implantation of the permanent pacemaker with a relatively rigid bipolar lead. It is concluded that these murmurs might be produced by vibrations caused by the pacing catheters and physical properties could be related the mechanism of this phenomenon.

Adult↗
PubMed1988

Correlation of conformation and phosphorylation and dephosphorylation of smooth muscle myosin.

The rate of phosphorylation and dephosphorylation of smooth muscle myosin by myosin light chain kinase and by two myosin light chain phosphatases (gizzard phosphatase IV and aorta phosphatase) are measured in various conditions; the relationship between the rate of phosphorylation and dephosphorylation of myosin and the myosin conformation is also studied. The rate of dephosphorylation of myosin was completely inhibited in the presence of 1 mM MgCl2 and ATP at low ionic strength where phosphorylated myosin forms a folded conformation. The inhibition was released when myosin formed either an extended monomer or filaments. The rate of phosphorylation of myosin was also affected by the conformation of myosin. The rate for a folded myosin was slower than those for an extended monomer and filamentous myosin. The phosphorylation and dephosphorylation of heavy meromyosin, subfragment-1, and the isolated 20,000-dalton light chain are not inhibited at low ionic strength, and the rate of phosphorylation and dephosphorylation was decreased with increasing ionic strength. KCl dependence of the rate of phosphorylation and dephosphorylation of myosin was normalized by using KCl dependence of subfragment-1, and it was found that the marked inhibition of the rate of phosphorylation and dephosphorylation of myosin is closely related to the change from an extended to a folded conformation of myosin.

Animals↗
PubMed1988

Intermediate filament reconstitution in vitro. The role of phosphorylation on the assembly-disassembly of desmin.

Desmin, the myogenic intermediate filament protein, is a phosphoprotein containing phosphoserine, in vivo. The role of phosphorylation on assembly-disassembly and organization of the desmin filament has remained obscure. We report here on a stable and purified system which enables a biochemical examination of desmin filament assembly and disassembly. Using this in vitro system, we carried out stoichiometrical phosphorylations by purified protein kinases. The extent of polymerization-depolymerization was estimated using procedures related to centrifugation and electron microscopy. The evidence we obtained suggests that disassembly of the desmin filament and inhibition of the NaCl-dependent polymerization of the soluble desmin can reversibly occur with either cAMP-dependent or Ca2+-activated, phospholipid-dependent desmin phosphorylation.

Animals↗