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Biomedical subjects

K Narita

Publications and source records attributed to K Narita.

At least 19 recordsLinked to original sources
PubMed1995

Phosphatidyl inositol-phospholipase C in squid photoreceptor membrane is activated by stable metarhodopsin via GTP-binding protein, Gq.

Phosphatidyl inositol-phospholipase C (PI-PLC) in squid retina was studied by immunoblotting and its activities were determined using [3H]phosphatidyl inositol bisphosphate ([3H]PIP2) as substrate. PI-PLC activity was found mostly in soluble fraction when the retina homogenate was treated with 400 mM KCl, but was associated with rhabdomal membranes under low salt conditions (20 mM Hepes). A protein with apparent molecular mass of 130kD was recognized by an antibody against PLC beta 4/norp A in both 400 mM KCl soluble and rhabdomal membrane fractions. A 42 kD protein recognized by antibody against the C-terminus of Gq alpha was also present in these two fractions. GTP gamma S stimulated only the PI-PLC activity associated with membrane and was magnesium dependent. PI-PLC activity was found to be (i) highly dependent upon calcium concentrations, (ii) enhanced by GTP but not by other nucleotides, and (iii) significantly stimulated by light at lower concentrations of GTP gamma S. The stimulation by light was still observed when irradiated membrane was incubated at 10 degrees C for 10 min and then mixed with GTP gamma S. These results suggest that stable metarhodopsin stimulates a PLC beta 4/norp A-like enzyme via a G-protein, Gq.

Animals↗
PubMed1994

Concomitant regulation of running activity and metabolic change by the ventromedial nucleus of the hypothalamus.

The aim of this study was to elucidate the involvement of kainate (KA) type glutaminergic, GABAergic and adrenergic receptors in the ventromedial nucleus of the hypothalamus (VMH) in inducing running activity and metabolic adaptations. Injection of either KA or bicuculline methiodide (BM), a GABAA receptor antagonist, into the VMH of conscious rats resulted in an increase in plasma glucose, norepinephrine, epinephrine and corticosterone, as well as running activity. KA or BM increased plasma glucose and catecholamine even under urethane anesthesia. Co-injection of either alpha- or beta-adrenergic receptor antagonist, i.e. phentolamine or timolol, respectively, with KA into the VMH of conscious rats elicited only a slight increase in plasma glucose and catecholamines, though it successfully induced hyper-running. However, plasma corticosterone was higher in the animals injected with adrenergic blockers, suggesting that an insufficient supply of energy substrates would enhance the activity of the hypothalamo-pituitary-adrenal system. We conclude that: (1) KA type glutaminergic and GABAergic receptors in the VMH are involved in regulating running activity and the sympathetic nervous system; (2) the brain noradrenergic system may mediate the KA action on the sympathetic nervous system.

Animals↗
PubMed1993

[Outpatient ESWL in 500 kidneys].

Between March 1989 and January 1992, 600 cases (636 kidneys) with upper urinary tract stones were treated with ESWL, using a Lithostar. Of these, 78.6% were carried out in our outpatient service, and in the last two years approximately 90% of cases have been treated as outpatient. We evaluated first 500 kidneys, treated with ESWL as outpatient. There were 481 cases involving 500 kidneys (19 bilateral cases). The ages of the 367 men and 114 women ranged from 16 to 77 years. There were 227 kidney stones and 273 ureter stones. Most of the stones were less than 20 mm. The average number of sessions and shock waves for each patient were 1.4 times and 6,988 waves, respectively. While 74% of the patients could be treated in only one session, 9% of them needed 3 sessions or more. Auxiliary measures were needed in 23 cases (D-J stent insertion in 5 cases and ureteral catheterization in 18 cases) and 474 cases (94.8%) were treated by in-situ procedures. At 3 months after treatment, 470 cases were evaluated and the stone-free rates of kidney stones and ureter stones were 70.3% and 84.5%, respectively with an overall stone-free rate of 78.1%. With regard to complications, the rate of the clinic visit because of pain after treatment was observed in 4.6% and higher than 38 degrees C in 2.5%. However, no serious perioperative complications occurred. From these results, outpatient ESWL was considered to be safe and efficient without serious complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Immunochemical detection of GTP-binding protein in cephalopod photoreceptors by anti-peptide antibodies.

We prepared polyclonal antibodies (Pab) against the following peptides: partial sequences of bovine transducin alpha subunit including the ADP-ribosylation sites sensitive to cholera toxin (CTX) and pertussis toxin (PTX) and the N-terminus of Drosophila GTP-binding protein q alpha (DGqN); Pab CTX, Pab PTX and Pab DGqN, respectively. These antibodies were specific to the peptides used as antigen and no crossreactivity was observed. Pab CTX and Pab PTX reacted with bovine transducin alpha subunit and the reactivity was lost by preincubation with the specific antigen peptide. Proteins of 41-42 kDa in octopus and squid photoreceptor membranes were recognized by Pab DGqN but not by Pab CTX or Pab PTX. Anti-alpha antibody (GA/1) reacted with the same bands as Pab DGqN recognized. These results suggest that the major GTP-binding protein in cephalopod photoreceptors is a Gq-type, similar to Drosophila Gq.

Amino Acid Sequence↗
PubMed1992

The absorbance spectrum and photosensitivity of a new synthetic "visual pigment" based on 4-hydroxyretinal.

The firefly squid, Watasenia scintillans, is the only animal known to possess a visual pigment in which the chromophore is 4-hydroxyretinal. This paper describes the absorbance spectrum and some properties of a synthetic "A4" visual pigment generated from bovine opsin and 4-hydroxyretinal. The absorbance spectrum of this pigment is compared with (a) bovine rhodopsin and (b) a rhodopsin template with the same lambda max as the synthetic visual pigment. The A4 pigment is shown to have an absorbance spectrum that is almost identical to that of a rhodopsin template. It is also shown that the photosensitivity and thermal stability of the A4 pigment, dispersed in detergent micelles, is essentially similar to that of rhodopsin.

Animals↗
PubMed1992

[A case of hepatic hydrothorax treated by pleuro-venous shunt].

We reported a successful pleuro-venous shunt operation (Pl-V shunt) for a patient of liver cirrhosis with secondary hydrothorax. A 78-year-old female was admitted to our hospital because of severe dyspnea and palpitation. Chest x-ray film revealed right sided massive pleural effusion. Over several weeks the chest tube drainaged about 1,500 ml of transudative fluid per day. We performed Pl-V shunting and pleural effusion subsequently decreased in amount and dyspnea disappeared. This Pl-V shunting is thought to be useful for such a patient with massive pleural effusion which failed to respond to medical therapy.

Aged↗
PubMed1992

[A successfully treated case of empyema with a large tracheal fistula after a radical operation of esophageal cancer by fixation and plombage with major pectoral muscle flap].

We reported a successfully treated case of empyema with a large tracheal fistula which had developed after a radical operation of esophageal cancer (reconstructed with stomach). This 59-year-old male was treated by the method of fixation and plombage with major pectoral muscle flap and thoracoplasty, because we could not use the omentum that were frequently used nowadays for closure of the fistula. The size of the tracheal fistula was a large as the main bronchus bronchoscopically. Postoperative care were the following, the endotracheal tube was inserted from the tracheal stoma to the left main bronchus and 9 days left hemi-ventilation was performed. Continuous suction was performed at the same time from the right main bronchus in order to prevent secretion and blood pour into the left lung. Bronchoscopical examination done 28 postoperative day, the small fistula remained the tip of the muscle flap. But 72 postoperative day, the surface of the fixed muscle flap was replaced by normal bronchial mucomembrane and tracheal fistula was obliterated. Major pectoral muscle could be used as local flap to obliterate empyema cavity associated with tracheal fistula. We believe that utilizing an muscle flap for those who had undergone abdominal operation like our case is a valuable method.

Empyema↗
PubMed1992

[An experience of laser therapy of lung cancer complicated with hemophilia A].

We applied an endoscopic Nd-YAG laser therapy for an early hilar lung cancer complicated with hemophilia A in a patient of 62-year-old male. Abnormality was pointed out by means of sputum cytology. But, no shadow of tumor was observed by chest x-ray films and computed tomogram. By a bronchoscopy, a mild irregular mucomembrane and stenosis without tumor were exhibited. By means of cytological diagnosis of an abrasive-washing specimen of that region, the presence of squamous cell carcinoma was proved. Also, he was diagnosed as factor VIII deficient hemophilia A. So we performed him a laser therapy in place of the operation and with an intrabronchial arterial infusion. After the laser treatment, the conditions progressed better without any recurrence but about one and a half years later, an intrapulmonary metastasis occurred. Then, radiation and chemotherapy have been applied and at present, the patient is in a good state although under the tumor-bearing condition.

Carcinoma, Squamous Cell↗
PubMed1991

Effects of divalent cations on the time course of post-tetanic decay of miniature endplate potential frequency in frogs.

Relatively high external Mg2+ specifically induces a shoulder in the post-tetanic decay of miniature endplate potential frequency at frog neuromuscular junctions. This effect is antagonized by Ca2+, but not by Sr2+ and Mn2+. This shoulder formation is not caused by Mn2+ or dinitrophenol in the medium. It is suggested that Mg2+ enters nerve terminals and displaces Ca2+ from internal stores; Mg2+ subsequently interferes with Ca2+ removal until the Mg2+ itself has been removed. The dinitrophenol result suggests that ATP-dependent Ca2+ extrusion is not permanently slowed. An equally likely and simpler explanation is that Mg2+ enters nerve terminals and the Mg2+ itself causes an increase in miniature endplate potential frequency. External Ca2+ competes with Mg2+ for channel entry and prevents this effect. The time course of the decay of miniature endplate potential frequency reflects the processes involved in Mg2+ extrusion and/or uptake.

2,4-Dinitrophenol↗
PubMed1991

Extramammary Paget's disease arising in mature cystic teratoma of the ovary.

We report a case of extramammary Paget's disease in ovarian mature cystic teratoma. The patient was a 70-year-old Japanese woman who complained of lower abdominal pain. Examination showed elevation of carcinoembryonic antigen and CA 19-9. Ultrasonography and computer tomography revealed a cystic tumor of the left ovary. The gross appearance of the resected ovary was typical for mature cystic teratoma. Microscopic observation revealed a lesion of Paget's disease within the squamous epithelium. The tumor cells had intracytoplasmic mucin and positive immunoreactivity for carcinoembryonic antigen, epithelial membrane antigen, and cytokeratin; but they were negative for S-100 protein and vimentin. On multiple and serial sections, underlying adenocarcinomas were not found either in the ovary or other primary sites. From these pathological findings, we concluded that the disease was an intraepithelial adenocarcinoma, possibly derived from multipotential cells in squamous epithelium of ovarian mature cystic teratoma. This is the first reported case, to our knowledge, of extramammary Paget's disease arising in mature cystic teratoma of the ovary.

Adenocarcinoma↗
PubMed1991

[Development of behavior rating scale for the elderly].

The purpose of this study was to develop a behavior rating scale to measure adaptation of the elderly using care staff as evaluators and to examine the reliability and validity of the scale. The behavior rating scale consists of 51 items and 5 subscales to measure areas of ADL, activity, interpersonal relationships, dementia syndromes, and socially irritating behavior. The scale was administered to 280 elderly residing in 4 nursing homes. Each reliability index, including internal consistency, test-retest, and inter-rater agreement was satisfactory. Validity was examined by relating total score or each subscale score to 19 external variables including physical condition, state of daily living, cognitive ability and personality. The correlations between external variables and the scale scores indicated that the behavior rating scale was valid.

Adaptation, Psychological↗
PubMed1991

[A case of presumed radiation optic neuropathy].

A case of a 37-year-old woman with radiation optic neuropathy was reported. She had undergone subtotal removal of the right orbital tumor (adenoid cystic carcinoma) by frontal craniotomy, followed by radiation therapy (64Gy). She had been quite well until she noticed a gradual loss of vision in her right eye 18 months later. Her visual acuity was 0.2 in the right eye and 1.5 in the left eye with right relative afferent pupillary defect and dense central scotoma. Funduscopy revealed optic disc swelling with surrounding retinal edema and small hemorrhage in the right eye. Fluorescein angiography revealed a hypoperfusion area and obstruction of the small retinal vessels in the posterior pole, but this was not large enough to explain the dense central scotoma. Although prednisolone therapy gave temporary improvement, the visual function gradually deteriorated.

Adult↗
PubMed1990

Spontaneous and evoked transmitter releases after concanavalin A treatment are affected differently by hypertonic low calcium solutions at frog neuromuscular junction.

Adding sucrose to the low calcium bathing solution made with no added calcium but containing Mg2+ EGTA to increase the tonicity elevated the basal frequency of miniature end-plate potentials (MEPPs) in the frog. The hypertonic low calcium solution also increased the rate at which the MEPP frequency rose in response to tetanic stimulation and elevated the level of the maximum frequency, which approached an asymptote. Pretreatment with concanavalin A (con A) greatly reduced the elevation in the basal frequency produced by hypertonic solutions. However, tetanic stimulation gave the same results as in untreated preparations when the tonicity was increased. Pretreatment with colchicine before the con A treatment eliminated the blocking action of con A on the MEPP frequency when the preparation was exposed to hypertonic solutions. Tetanic stimulation produced increases in MEPP frequency similar to those observed in normal junctions immersed in hypertonic solutions. Caffeine elevated the basal level of the MEPP frequency. Tetanic stimulation in the caffeine solution caused the increase in the MEPP frequency; the higher the basal level rose, the higher the maximum level became. However, the rate at which the MEPP frequency rose remained unchanged. The present results indicate that hypertonicity increases not only the basal frequency of MEPPs but also the slope at which the MEPP frequency is elevated by tetanic stimulation, both mechanisms being different and that the rate and magnitude of the tetanic potentiation of MEPP frequency are not simply determined by the pre-tetanus frequency.

Action Potentials↗
PubMed1990

Mn and Mg influxes through Ca channels of motor nerve terminals are prevented by verapamil in frogs.

At frog neuromuscular junctions immersed in solutions containing 0.5 mM Mn2+, verapamil (40 microM) reduced the increase in miniature end-plate potential (MEPP) frequency produced by tetanic stimulation (50 Hz, 2 min) of the motor nerve to 5% of that in the absence of verapamil. In solutions containing 5 mM Mg2+, verapamil reduced the tetanic increase in MEPP frequency to 8% of that in the absence of verapamil. Verapamil added to solutions containing 0.15 mM Ca2+ decreased the tetanic rise in MEPP frequency to 6% of the control value. In low Ca2+ (nominally Ca2(+)-free) solutions, verapamil decreased the tetanic rise to 70% of the control value. The present results suggest that Mn2+ and Mg2+, as well as Ca2+, enter the nerve terminal through Ca2+ channels during nerve stimulation and promote transmitter release. In addition to its effect on the Ca2+ channel, verapamil at higher concentrations appears to have inhibitory effects on the acetylcholine-gated end-plate channel and on the Na+ channel as suggested by its depressive effects on the amplitudes of MEPPs, end-plate potentials and nerve terminal action potentials.

Action Potentials↗
PubMed1990

Changes in cerebral free fatty acids and triacylglycerols in focal cerebral ischemia.

1. Focal cerebral ischemia was induced in anesthetized rats by occluding the stem of the proximal middle cerebral artery. 2. The levels of free fatty acids, such as stearic and arachidonic acids, in the ischemic cerebral cortex increased progressively until 60 min after occlusion, but thereafter they decreased rapidly. 3. In contrast to the time-dependent changes in free fatty acids, the levels of triacylglycerol (TAG) in the ischemic cerebral cortex continued to increase for 120 min after occlusion. Increases in TAG-palmitate, -stearate and -arachidonate accounted for the increase in the triacylglycerol level. 4. The pattern of the lipid changes in focal cerebral ischemia differs from those reported in bilateral diffuse cerebral ischemia induced by arterial occlusion or in decapitation ischemia.

Animals↗
PubMed1990

[A case of bone and lung metastasis of breast cancer successfully treated with radiotherapy, chemotherapy and endocrine therapy].

A 34-year-old female patient with breast cancer metastasizing to bone had a remission after a course of treatment with medroxyprogesterone acetate (MPA) 1,200 mg/day, but again had a metastasis to the lungs. The patient was then instituted on a combination therapy with UFT 400 mg/day, and MPA 1,200 mg/day. As a result, the pulmonary metastasis disappeared, along with the consolidation of the bone involved.

Adenocarcinoma↗
PubMed1990

[Resected cases of middle lobe primary cancer].

Of 200 lung cancer lesions resected in our hospital, there were 15 cases (7.5%) with middle lobe origin. The histological types were adenocarcinoma in 13 patients (4 patients with alveolar cell carcinoma), squamous cell carcinoma in one and large cell carcinoma in one. These patients were classified into two groups according to the type of operation they received and each group was evaluated. Group I (resection of the middle lobe) included 8 patients. Each one of Stage IIIB and Stage IV received the operation to improve their symptoms. The six patients of Stage I received only middle lobectomy as absolute curable cases. Group II (resection of the middle and lower lobes) included 7 patients, who had preoperative diagnosis of stage III. Two of them were postoperatively found to be cases of Stage I and Stage II. Although it was still short-term, the follow-up evaluation proved that these patients survived without local recurrence and distant metastasis, except for two with pleural dissemination and one with cerebral metastasis, who had received lobectomy as palliative operation. No difference was observed between the two groups receiving different types of operation.

Adenocarcinoma↗