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Biomedical subjects

M Inagaki

Publications and source records attributed to M Inagaki.

At least 307 records · Page 17Linked to original sources
PubMed1990

Involvement of protein kinase C in the regulation of assembly-disassembly of neurofilaments in vitro.

Protein kinase C phosphorylated the major mammalian neurofilament protein (NF-L) with approximately 3 mol phosphate per mol protein. The phosphorylated NF-L no longer formed the filaments. Sequential analysis of the tryptic phosphopeptides, together with the known primary sequence, revealed that Ser-12, Ser-27, Ser-33 and Ser-51 were phosphorylated by protein kinase C. These findings contribute toward elucidation of mechanisms regulating the functions of neurofilaments.

Amino Acid Sequence↗
PubMed1990

Phosphorylation sites linked to glial filament disassembly in vitro locate in a non-alpha-helical head domain.

Glial fibrillary acidic protein (GFAP), the intermediate filament component of astroglial cells, can serve as an excellent substrate for both cAMP-dependent protein kinase and protein kinase C, in vitro. GFAP phosphorylated by each protein kinase does not polymerize, and the filaments that do polymerize tend to depolymerize after phosphorylation. Dephosphorylation of phospho-GFAP by phosphatase led to a recovery of the polymerization competence of GFAP. Most of the phosphorylation sites for cAMP-dependent protein kinase and protein kinase C on GFAP are the same, Ser-8, Ser-13, and Ser-34. cAMP-dependent protein kinase has one additional phosphorylation site, Thr-7. All the sites are located within the amino-terminal non-alpha-helical head domain of GFAP. These observations pave the way for in vivo studies on organization of glial filaments.

Animals↗
PubMed1990

Changes in lipoprotein composition in hypertriglyceridemic patients taking cholesterol-free fish oil supplements.

Fish oils rich in n - 3 fatty acids (FAs) have been shown to markedly lower levels of very low density lipoproteins (VLDL), but not the low density lipoproteins (LDL) which are derived from VLDL. Changes in the size and chemical composition of lipoproteins may affect their metabolism. In order to examine the effects of n - 3 FAs on lipoprotein metabolism, 6 patients with hypertriglyceridemia were given 6 g n - 3 FAs/day. Plasma lipid and apoprotein (apo A-I, A-II, B, E, C-II, C-III) levels (mg/dl) were measured before and after 4 weeks of treatment. Changes in lipoprotein size were assessed by gel chromatography. n - 3 FAs lowered VLDL cholesterol (58 +/- 35 to 40 +/- 30, P less than 0.01) and total triglyceride (410 +/- 170 to 236 +/- 114, P less than 0.01). In spite of this, LDL cholesterol levels did not decrease, and apo B levels increased (98 +/- 28 to 111 +/- 27, P less than 0.05). HDL cholesterol rose (31 +/- 5 to 34 +/- 7, P less than 0.05). The lipid content of smaller VLDL particles was reduced by over 40%, but the protein content was largely unchanged. Large triglyceride-rich lipoprotein particles were reduced to a greater extent than were small particles. These changes in VLDL particle size and composition may enhance the synthesis of LDL in hypertriglyceridemic patients taking n - 3 FA supplements.

Blood Proteins↗
PubMed1990

Retrobulbar optic neuritis in a two-year-old boy.

We report a 2-year-4-month-old boy with retrobulbar optic neuritis. He had a sudden onset of impaired vision, which progressed to total blindness within a day. The visual evoked potential (VEP) showed no activity, but the electroretinogram was normal. Computed tomography (CT) and magnetic resonance imaging (MRI) showed no abnormal findings in the visual tract. The cerebrospinal fluid (CSF) myelin basic protein (MBP) level was elevated and serum anti-myelin antibody was positive. These findings suggested that optic neuritis in our patient was induced by retrobulbar demyelination, perhaps as a result of an autoimmune process. His visual impairment recovered gradually, but not completely, following oral prednisolone therapy. We have followed him for one year since discharge and have found neither recurrence of optic neuritis nor any other neurological disorders. Optic neuritis in children is rare and, to our knowledge, this patient is one of the youngest to be reported. This case suggests that autoimmune mechanisms may induce optic neuritis even in early childhood. In addition to VEP and MRI studies, the CSF MBP and serum anti-myelin antibody can be useful in the diagnosis and follow-up the patients with optic neuritis.

Child, Preschool↗
PubMed1990

Effects of phosphorylation of the neurofilament L protein on filamentous structures.

Effects of phosphorylation of the neurofilament L protein (NF-L) on the reassembly system were studied by both sedimentation experiments and low-angle rotary shadowing. Bovine spinal cord NF-L was phosphorylated with 3-4 mol/mol protein by either the catalytic subunit of cAMP-dependent protein kinase or protein kinase C. Phosphorylated NF-L could not assemble into filaments. Phosphorylation by either cAMP-dependent protein kinase or protein kinase C inhibited the same step of the reassembly process. Phosphorylated NF-L remained as an 8-chain complex even in favorable conditions for reassembly. The extent of the effect of phosphorylation on the filamentous structure of NF-L was also investigated by using the catalytic subunit of cAMP-dependent protein kinase. The amount of unassembled NF-L increased linearly with increased phosphorylation in the sedimentation experiments. Structural observations indicated that 1 or 2 mol of phosphorylation is enough to inhibit reassembly and to induce disassembly, and the disassembly process was also observed. The filaments were shown to unravel with disassembly. Star-like clusters, which we reported as being the initial stage of reassembly, were also identified.

Animals↗
PubMed1990

Genotypic differentiation of intrahepatically transplanted hyperplastic nodule cells of analbuminemic and normal rat origin by polymerase chain reaction.

DNA fragments encompassing the region of the seven-base-pair deletion in the albumin gene, which is a characteristic abnormality of Nagase's analbuminemic rat (NAR), were amplified by polymerase chain reaction, and we could differentiate the genotypes of normal rat, homozygous NAR and heterozygous NAR electrophoretically. This genotyping method was applied to the differentiation of hyperplastic nodules on immunostained tissue sections in the intrahepatic transplantation model. When the hyperplastic nodule cells of normal rat were transplanted to the livers of homozygous NAR, the donor cells were effectively differentiated from the host cells by the genotype.

Albumins↗
PubMed1990

[Eight cases of diphyllobothriasis].

Eight cases of diphyllobothriasis have been experienced in the Juntendo University Hospital. Seven of the 8 patients excreted tapeworm fragments. Eggs of Diphyllobothrium latum were found in the feces in 5 cases. One patient had a history of ingestion of raw trout (Sushi), and 2 raw salmon. One might have been infected in foreign countries, and 3 could not tell the source of infection. Bithoinol was administered orally to 7 patients. Four of the 7 excreted the worm and the scolex was recognized in three of the four. Neither recurrence nor abnormal findings have been recognized so far.

Adult↗
PubMed1990

Physical training of the patients with coronary heart disease: noninvasive strategies for the evaluation of its effects on the oxygentransport system and myocardial ischemia.

To clarify the central effects of physical training on patients with coronary heart disease, 81 subjects were selected for the present study. Evaluations of the oxygen transport system function were performed according to the definition proposed by Bruce and others in terms of FAI (functional aerobic impairment), LVI (left ventricular impairment) or MRI (myocardial reserve impairment), CRI (chronotropic reserve impairment) and PCI (peripheral circulatory impairment). Remarkable improvement in left ventricular impairment was found in those patients with single vessel disease or those who experienced disappearance of chest pain after the completion of the program. In another series of study on myocardial perfusion performed on 11 patients with coronary heart disease, improvement in ischemia was also demonstrated in 7 of 8 patients who revealed redistribution pattern in 201TL exercise stress images specifying myocardial ischemia. In conclusion, exercise training could induce improvements not only the left ventricular functions characterized by increased maximal pressure rate product and maximal heart rate, but also in myocardial ischemia. Further studies are needed to specify its effects, since natural progression or regression of the disease process itself may influence the results.

Coronary Disease↗
PubMed1990

[Protective effects of DBcAMP on ischemic liver failure in dogs].

We studied protective effects of Dibutyryl cyclic AMP (DBcAMP) which is a permeable form of cyclic AMP on ischemic liver failure (ischemic time: 90 minutes). Mongrel dogs were used. A portal-systemic bypass was established by inserting a heparinized catheter between the splenic vein and the femoral vein. Acute liver failure was induced by the en bloc clamp of the porta hepatis. In the treated group, 0.1 mg/kg/min (total dose, 300 mg) of DBcAMP was injected intravenously from three hours before the clamp to the end of the experiment. The control group was injected physiological saline. Effects of DBcAMP were evaluated according to survival rates, blood pressure, serum biochemical findings, hepatic blood flow, ATP levels in liver tissues and histological findings. The survival rates were 16% in the control group, and 88% in the treated group. The mean blood pressure after reperfusion was rapidly decreased in the control group while in the treated group, it was maintained nearly 100 mmHg. Serum biochemical findings, hepatic blood flow and tissue ATP levels were significantly improved in the treated group. On histological findings, necrosis with bleeding was observed one day after ischemia in the control group while in the treated group mild chronic ischemic change without necrosis was observed on two weeks after ischemia. In conclusion, ischemic liver failure was apparently protected by the administration of DBcAMP.

Adenosine Triphosphate↗
PubMed1990

Long-term survival after brain metastasis from endometrial cancer.

A case is reported of prolonged survival after radical hysterectomy for poorly differentiated adenocarcinoma of the endometrium and resection of metastatic carcinoma of the brain followed by radiation therapy. The 43-year-old patient has survived for seven years after hysterectomy and six years 10 months after excision of the brain metastasis. Our results show that the surgical excision of a single metastatic lesion of the brain with postoperative irradiation offers hope of prolonged survival in patients with a solitary brain metastasis and no evident systemic disease.

Adenocarcinoma↗
PubMed1990

[A case of cardiac tumor found during examination in orthostatic hypotension].

We report a case of left atrial myxoma found when examination was made for the cause of orthostatic hypotension. The case was that of a man of 61 years of age. For the previous 2 years, the man had felt dizzy only at the standing or sitting position. The blood pressure was 90/50 at recumbency and 64/40 at the sitting position. Echocardiographic study revealed a left atrial tumor, which fell into the left ventricular cavity and prevented the blood from filling the left ventricular cavity. This effect was more severe at the sitting position than at recumbency. Resection of the tumor was carried out. It was a myxoma with a diameter of 3.5 cm with a stalk adhering to the postero-inferior wall of the left atrium. After the removal of the tumor, the patient's complaint and orthostatic hypotension disappeared; blood pressure was 102/60 at recumbency and 98/64 at sitting position. Orthostatic dizziness has been reported in some cases as one of the symptoms of the intracardiac tumor. But the state of aggravation at the sitting position has never been observed during actual echocardiographic study. The myxoma adhered to the postero-inferior wall of the left atrium, which site might be associated with the symptom (orthostatic hypotension).

Diagnosis, Differential↗
PubMed1989

Clinical evaluation of a pasteurized factor XIII concentrate administration in Henoch-Schönlein purpura. Japanese Pediatric Group.

Arthral, abdominal and renal symptoms in Henoch-Schönlein purpura (HSP) were scored. Coagulation factor XIII (F XIII) activity was determined in fifty-six children with HSP and the correlation with the severity score of the clinical symptoms was investigated. As a result, it was found that the decrease in F XIII level was correlated with the severity score of clinical symptoms, particularly abdominal symptoms. Based on the results, a controlled study was performed in 24 cases with moderate symptoms divided into a group treated with F XIII concentrate and a non-treated group to investigate clear-cut efficacy as a next study. In three days after the administration the symptoms were improved remarkably in accordance with the increase of F XIII level compared with non-treated group and scoring of clinical symptoms was confirmed to be useful for assessing the application of the F XIII concentrate to HSP.

Abdominal Pain↗
PubMed1989

Ca2+-dependent deimination-induced disassembly of intermediate filaments involves specific modification of the amino-terminal head domain.

Peptidylarginine deiminase (proteinarginine iminohydrolase, EC 3.5.3.15) converted some arginine residues to citrulline residues in soluble vimentin, in a micromolar Ca2+-dependent manner and resulted in the loss of polymerization competence of the intermediate filament protein. When about 8 mol of residues/mol of vimentin were deiminated, there was a complete loss of filament forming ability. This enzyme also deiminated vimentin filaments which had been polymerized, and deimination of vimentin filaments resulted in filament disassembly. Similar results were obtained with other intermediate filaments such as desmin and glial filaments. High performance liquid chromatography and amino acid analyses of lysine-specific protease-generated fragments from deiminated vimentin (about 8 mol of citrulline/mol of vimentin) showed a differential deimination of three structural domains. The head domain was predominant. These observations suggest that the head domain strongly influences integrity of the intermediate filament.

Amino Acids↗
PubMed1989

Direct inhibitory synaptic connections of pontine omnipause neurons with burst neurons in Forel's field H related to vertical saccades in the cat.

This study investigated synaptic connections of omnipause neurons (OPNs) in the midline pontine tegmentum with medium-lead burst neurons (BNs) in Forel's field H (FFH), using the spike-triggered averaging technique in chronically prepared alert cats. OPNs were identified behaviorally by tonic firing during the intersaccadic period, whereas medium-lead BNs were identified by spike bursts during upward or downward saccades. A positive shift of field potential in the BN area, associated with suppression of the BNs' bursts, was observed during tonic firing of OPNs and during microstimulation in the OPN area. Averaging of BN area field potentials triggered by spikes of single OPNs on both sides, which were antidromically evoked from the BN area, revealed positive waves with monosynaptic latencies. These results strongly suggest that OPNs on both sides make direct inhibitory synaptic connections with vertical eye movement-related medium-lead BNs in the FFH.

Action Potentials↗
PubMed1989

Protein kinase C phosphorylation of desmin at four serine residues within the non-alpha-helical head domain.

We reported that phosphorylation by either cAMP-dependent protein kinase or protein kinase C (Ca2+/phospholipid-dependent enzyme) in vitro induces disassembly of the desmin filaments (Inagaki, M., Gonda, Y., Matsuyama, M., Nishizawa, K., Nishi, Y., and Sato, C. (1988) J. Biol. Chem. 263, 5970-5978). For this subunit protein, Ser-29, Ser-35, and Ser-50 within the non-alpha-helical head domain were shown to be the sites of phosphorylation for cAMP-dependent protein kinase (Geisler, N., and Weber, K. (1988) EMBO J. 7, 15-20). In the present work, we identified the sites of desmin phosphorylated in vitro by other protein kinase which affects the filament structure. The protein kinase C-phosphorylated desmin was hydrolyzed with trypsin, and the phosphorylated peptides were isolated by reverse-phase chromatography. Sequential analysis of the purified phosphopeptides, together with the known primary sequence, revealed that Ser-12, Ser-29, Ser-38, and Ser-56 were phosphorylated by protein kinase C. All four sites are located within the non-alpha-helical head domain of desmin. Ser-12, Ser-38, and Ser-56, specifically phosphorylated by protein kinase C, have arginine residues at the carboxyl-terminal side (Arg-14, Arg-42, and Arg-59, respectively). Ser-29 phosphorylated by both protein kinase C and cAMP-dependent protein kinase has arginine residues at the amino and carboxyl termini (Arg-27 and Arg-33). These findings support the view that the head domain-specific phosphorylation strongly influences desmin filament structure; however, each protein kinase differed with regard to site recognition on this domain.

Amino Acid Sequence↗