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Biomedical subjects

N Murakami

Publications and source records attributed to N Murakami.

At least 325 records · Page 18Linked to original sources
PubMed1993

Effect of a central CRF antagonist on cardiovascular and thermoregulatory responses induced by stress or IL-1 beta.

We investigated the role of central corticotropin-releasing factor (CRF) in the development of cardiovascular and thermal responses induced by stress or by interleukin-1 beta (IL-1 beta) in free-moving rats. Intracerebroventricular (icv) injection of alpha-helical CRF9-41 (10 micrograms), a CRF receptor antagonist, significantly attenuated hypertension, tachycardia, and a rise in body temperature induced by cage-switch stress, a mild stress. However, icv injection of alpha-helical CRF9-41 (10 micrograms) had no effect on hypertension, tachycardia, or fever induced by intraperitoneal (ip) injection of IL-1 beta (2 micrograms/kg) or icv prostaglandin E2 (PGE2, 100 ng). In contrast, icv injection of alpha-helical CRF9-41 (10 micrograms) significantly attenuated hypertension, tachycardia, or fever induced by icv injection of IL-1 beta (20 ng). The present results suggest that central CRF has an important role in the development of the cage-switch stress-induced responses, but it does not seem to contribute to the hypertension, tachycardia, and fever induced by ip IL-1 beta or by central PGE2. However, it is possible that when IL-1 beta directly acts on the central nervous system, some of its actions are mediated by central CRF.

Animals↗
PubMed1993

Cardiac glycoside-induced elevation of intracellular Na+ ion concentration in human erythrocytes studied by 23Na NMR spectroscopy: relationship between inotropy speed and elevation rate of intracellular Na+ ion concentration.

Elevation of intracellular sodium ion concentration in human erythrocyte induced by the cardiac glycoside, proscillaridin, and its four derivatives was measured using 23Na NMR spectrometry. In this examination, there was a significant correlation between the time to half maximum inotropic effect and the time to maximum of Na+ concentrations in human erythrocyte, determined by 23Na NMR.

Animals↗
PubMed1993

Isolation and identification of anti-tumor-promoting principles from the fresh-water cyanobacterium Phormidium tenue.

Bioassay-directed fractionation of the extract of the cyanobacterium P. tenue led to the isolation of the three classes of glycolipids, viz., monogalactosyl diacylglycerol (MGDG), digalactosyl diacylglycerol (DGDG), and sulfoquinovosyl diacylglycerol (SQDG) as anti-tumor-promoters. In comparing the anti-tumor-promoting effect of the three classes of glycolipids with various acyl residues, MGDG and DGDG inhibited tumor promotion more intensely than SQDG. With respect to MGDG and DGDG, the inhibitory activity of each glycolipid possessing a single pair of acyl residues was also investigated after HPLC separation. Among the 17 tested MGDGs (1a--h) and DGDGs (2a--i), three of the DGDGs (2a, b, e) showed more potent inhibitory activity toward tumor promotion than the others.

Anticarcinogenic Agents↗
PubMed1993

Absolute stereostructures of trifoliones A, B, C, and D, new biologically active diterpenes from the tuber of Sagittaria trifolia L.

Four new biologically active diterpenes, trifoliones A, B, C, and D, were isolated from the tuber of Sagittaria trifolia L. together with three new glycosides, sagittariosides a and b and arabinothalictoside. Their stereostructures were determined on the basis of chemical and physicochemical evidence which included the application of a modified Mosher's method and an exciton chirality method. Trifoliones A, B, C, and D exhibited inhibitory effects on the histamine release from rat mast cells induced by compound 48/80 or calcium ionophore A-23187.

Animals↗
PubMed1993

Auto-growth inhibitory substance from the fresh-water cyanobacterium Phormidium tenue.

An extract of the cyanobacterium P. tenue showed a significant inhibitory effect on its own growth. Bioassay-directed fractionation has led to the identification of the auto-growth inhibitory substance as a mixture of fatty acids. Unsaturated fatty acids such as linoleic and linolenic acids appear to be predominantly responsible for the auto-growth inhibitory effect.

Cyanobacteria↗
PubMed1993

Elatosides A and B, potent inhibitors of ethanol absorption in rats from the bark of Aralia elata Seem: the structure-activity relationships of oleanolic acid oligoglycosides.

By monitoring the inhibitory effect on ethanol absorption in rats, new active saponins named elatosides A and B were isolated from the bark of Aralia elata Seem. together with elatosides C and D. The structures of elatosides A, B, C, and D were elucidated on the basis of chemical and physicochemical evidence. The inhibitory effects of several oleanolic acid oligoglycosides on ethanol absorption have been examined and some structure-activity relationships have been found.

Absorption↗
PubMed1993

[Chemical fluctuation of the constituents during the drying of Ginseng radix and Ginseng radix Rubra. Crude drug processing by far-infrared treatment].

In order to evaluate the utility of far-infrared drying method for crude drugs, the efficiency in the drying process of Ginseng Radix and Ginseng Radix Rubra was examined. Furthermore, chemical fluctuation of the constituents of Ginseng Radix and Ginseng Radix Rubra, which may occur during their drying process, has been investigated by means of HPLC quantitative analysis for ginsenosides and malonyl-ginsenosides, and TLC qualitative analysis for lipophylic constituents. It has been found that the far-infrared drying method (oven temperature 45 degrees C) dried Ginseng Radix faster without reducing both ginsenosides and malonyl-ginsenosides in comparison with the conventional drying methods such as an air drying and a hot-air drying.

Chromatography, High Pressure Liquid↗
PubMed1993

Serum sialic acid levels in the diagnosis and follow-up of subacute granulomatous thyroiditis.

To evaluate the usefulness of monitoring serum sialic acid (SA) levels for diagnosis and follow-up of subacute granulomatous thyroiditis (SAT), 43 patients were studied at our clinic. In the acute phase of the disease their SA levels averaged 104.9 +/- 19.7 mg/dl (normal 44-69 mg/dl). In the recovery phase SA levels returned to a range of 60.5 +/- 6.9 mg/dl. However, an increase in SA (87.4 +/- 18.2 mg/dl) was detected at the time of recurrence in 14 patients. In 29 non-recurrent patients, serum SA gradually reduced during the course of therapy and normalized in all patients by the time glucocorticoid therapy was discontinued. Thyroglobulin (Tg) and the erythrocyte sedimentation rate (ESR), however, had normalized in only half the cases even at the time of cessation of therapy (Tg 5/11, ESR 4/8). C-reactive protein (CRP) returned to negative in most patients (19/24) only one week after initiation of the therapy. These results suggested that the monitoring of SA levels can be a useful tool in diagnosis and follow-up of SAT.

Adult↗
PubMed1993

Cardiovascular, thermal and behavioral sensitization to methamphetamine in freely moving rats.

Mean arterial blood pressure (MAP), heart rate (HR), body temperature (BT) and locomotive activity (LA) were measured simultaneously after i.p. or i.c.v. injection of methamphetamine (MAH) using a biotelemetric system. The system enabled us to observe the parameters in freely moving rats under minimum stress. MAH (1 mg/kg) given by i.p. injection significantly increased MAP, HR, BT and LA, as compared with the saline-control. MAH (5, 50 micrograms) administered by i.c.v. injection stimulated responses of HR, BT and LA. After the i.p. injections of MAH (1 mg/kg) on days 1, 4, 8, 11 and 15, MAH was administered either through i.p. (1 mg/kg) or i.c.v. (50 micrograms) route on day 18. In addition to the LA sensitization induced by i.p. and i.c.v. administration of MAH, it was found for the first time, to our knowledge, that the repeated i.p. injections potentiated the responses of MAP and BT to the subsequent injection of MAH through i.p., but not i.c.v., route. The latter finding suggests that the sensitization, produced by the repeated i.p. injections, affected responses that MAH induced either peripherally or centrally through a peripheral humoral factor or an afferent nervous system.

Animals↗
PubMed1993

[A case of tuberculous meningitis with abnormal contrast enhancement of choroid plexus on CT and MRI].

A 55-year-old man first noted a swelling on his back in September 1990, when CT scan of his chest suggested a pleural fistula and a cold abscess. In the following month, he became pyrexial and felt nauseated with headache. Subsequently he was transferred to our hospital. Results of neurological examination were abnormal only in that he had neck stiffness and bilateral nystagmus with drowsiness. Cerebrospinal fluid (CSF) showed turbid yellowish fluid with an opening pressure of 360 mmH2O, a protein content of 173 mg/dl, a glucose level of 19 mg/dl, and a white blood cell count of 3,024/ml (75% polymorphs, 25% lymphocytes). Tryptophane test was positive. No bacteria, fungi or acid-fast bacilli were seen on direct smear. Adenosine deaminase activity in CSF was 13.9 IU/l. Antibiotics, antituberculous drugs, corticosteroids and glycerol were administered. The clinical course in the hospital was satisfactory for the next two months, but a contrast enhanced CT scan showed prominent enhancement in the left choroid plexus, and MRI revealed another mass in the subarachnoidal space under the right frontal lobe. An open biopsy was done on the massive lesion in the frontal lobe. Macroscopically, this lesion was an encapsulated granulomatous one. On the other hand, there were groups of epitheloid cells with micronecrosis in their centers microscopically. These findings were compatible with tuberculoma, in spite of the absence of acid-fast bacilli or caseous necrosis. Medication was intensively continued: a follow-up CT showed gradual reduction of the choroid plexus lesion and shrinkage of the left lateral ventricle.

Choroid Plexus↗
PubMed1993

[Weber's syndrome of ischemic vascular origin--a clinical and neuroradiologic study].

A series of 4816 patients with cerebrovascular disease have undergone CT and/or MRI examinations over the last 25 years at the Higashi Nagoya National Hospital and the Nagoya National Hospital. Of these, we experienced 5 cases (4 men and 1 woman) of Weber's syndrome: two cases were resulted from cerebral embolism and three from cerebral thrombosis. All of the patients had left hemiparesis and right oculomotor palsy. On full investigation, complete unilateral external and internal oculomotor palsy was seen in two patients, while the remaining three patients showed pupillary sparing. The patients with complete oculomotor palsy presented with left hemiparesis as the initial symptom. In addition to oculomotor palsy and crossed hemiparesis, two patients had paralysis of the face and one patient had tongue muscle on the opposite side of the lesion and disorders of sensation. Positive Babinski's sign was found in four of the five patients. In one patient with unilateral glossoplegia on the side of hemiparesis, CT or MRI revealed a limited low-density or low signal intensity (T1) area in the inner part of the crus cerebri, and in the other patient who also had hemihypesthesia, the low-density or low-signal intensity (T1) area expanded into the dorsal midbrain. We would like concluded that the frequency of Weber's syndrome was very low though this syndrome was well celebrated, and the careful clinical observation of the neurological features of affected patients guided to the obvious site of lesion in the midbrain.

Aged↗
PubMed1993

The clearance rate of chylomicron retinyl ester from plasma can be used to distinguish rats with cirrhosis from those with portacaval shunt.

Effects of carbon tetrachloride treatment and portacaval shunt surgery on exogenous chylomicron retinyl ester clearance from rat plasma were analyzed assuming three-compartment model kinetics. In rats with cirrhosis and in those with Eck fistulas, the relative pool size of compartment 2 decreased (0.20 and 0.36, respectively) compared with controls (0.82). The relative mass of compartment 3 significantly increased in rats with cirrhosis (1.55) or Eck fistula (0.19) compared with control rats (0.11). The cirrhotic and Eck fistula groups were indistinguishable on the basis of these parameters and on the basis of indocyanine green test values. However, the cirrhosis and Eck fistula groups differed clearly from each other with respect to fractional efflux rate constants (l2, l3), where the constant l2 is from compartment 2 and the l3 is from compartment 3. Both values decreased in cirrhotic rats, suggesting that the hepatic uptake of chylomicron retinyl esters was impaired by carbon tetrachloride. On the other hand, Eck fistula rats did experience dramatic increases in l3, implying that the hepatic uptake of chylomicron retinyl esters from compartment 3 was enhanced by portacaval shunting. Elevation of the plasma estrogen level observed in Eck fistula rats may be responsible for the induction of low-density lipoprotein receptors on hepatocytes and for the subsequent enhancement of l3. These results suggest that a three-compartment model of plasma retinyl ester disappearance kinetics gives important quantitative information about hepatic function. Clinical application of the chylomicron retinyl ester clearance test is discussed for estimating hepatic function reserves and for differential diagnosis of portal hypertension.

Animals↗
PubMed1993

[A case of recurrent colon cancer treated markedly effective with 5'-DFUR].

A 71-year-old male with recurrent colon cancer was admitted to our hospital with obstructive jaundice. Virchow's node metastasis was palpable in his neck. The enlarged intraabdominal lymphnodes due to recurrence and liver metastasis were demonstrated on computed tomography. Bile duct obstruction was treated by expandable metallic biliary endoprosthesis. 5'-DFUR (5'-deoxy-5-fluorouridine) was administered orally at 600 mg daily. Virchow's node metastasis completely disappeared by 46 days after administration of 5'-DFUR. The enlarged intraabdominal lymphnodes and liver metastasis disappeared on computed tomography. No significant side effects from 5'-DFUR were encountered for 18 months. 5'-DFUR appears to be a useful and safe treatment for recurrent colon cancer.

Administration, Oral↗
PubMed1992

Localization of myosin IIB at the leading edge of growth cones from rat dorsal root ganglionic cells.

Primary cultures of rat dorsal root ganglionic (DRG) cells were stained with isoform-specific antibodies against non-muscle myosin II. Antibodies against the brain type myosin (MIIB) stained the peripheries of growth cones and non-neuronal cells. Double staining of the cells with the anti-myosin antibodies and rhodamine-phalloidin or anti-actin antibodies indicated that MIIB co-exists, with F-actin, at the leading edge. Antibodies against platelet myosin stained neither leading edges nor neurites, but stained the cell bodies of neurons and the stress fibers of non-neuronal cells. These results suggest that MIIB functions in the motility of the leading edge of DRG cells.

Animals↗
PubMed1992

Immunoreactive corticotropin-releasing hormone levels in the hypothalamus of female Wistar fatty rats.

We have studied immunoreactive corticotropin-releasing hormone (CRH) levels in the hypothalamus of female Wistar fatty rats, a strain with the fa gene transferred from the Zucker rat to the Wistar Kyoto rat, in an attempt to understand the role of CRH in the development of obesity. A study was conducted with 5-week- and 12-week-old female Wistar fatty rats and lean littermates. There was no significant difference in hypothalamic CRH levels between lean and obese rats at the age of 5 weeks (1887 +/- 99.6 vs. 1767 +/- 124 pg/tissue; mean +/- S.E.M.). Hypothalamic CRH immunoreactivities, however, were significantly lower in 12-week-old obese rats (2361 +/- 132 pg/tissue) than those in lean littermates (2992 +/- 118 pg/tissue; P less than 0.05). The difference of CRH contents between the lean and obese group becomes apparent as they grow up and develop obesity.

Aging↗
PubMed1992

Regulation of interleukin-1 receptors on AtT-20 mouse pituitary tumour cells.

To study the cellular mechanisms of interleukin-1 (IL-1) in the pituitary corticotroph, we studied the properties of IL-1 receptors on a mouse pituitary ACTH-producing cell line, AtT-20. Scatchard plot analysis revealed a single type of receptor with a Kd (dissociation constant) of 93 pM, and 482 binding sites/cell. [125I]IL-1 alpha binding competed with IL-1 alpha and IL-1 beta in an equimolar fashion. A 24 h pre-incubation with either CRH, epinephrine or nor-epinephrine increased the [125I]IL-1 alpha binding sites in the AtT-20 cells and conversely, a similar pre-incubation with either dexamethasone or tumour necrosis factor-alpha (TNF alpha) decreased them without affecting the affinity of the receptors in either case.

Adrenocorticotropic Hormone↗
PubMed1992

Immunohistochemical studies on the distribution of cellular myosin II isoforms in brain and aorta.

The distribution of nonmuscle myosin isoforms in brain and aorta was studied by using polyclonal antibodies against two synthetic peptides selected from a region near the carboxyl terminus of bovine brain (peptide IIB) and human macrophage (peptide IIA) myosin. Immunoblots of brain homogenates and purified myosin showed two major bands stained by anti-peptide IIB (MIIB1 and MIIB2) and a minor band stained by anti-peptide IIA (MIIA2). Polyclonal anti-human platelet myosin antibodies did not react with MIIB isoforms. In cryosections from bovine, rat, and mouse brains, anti-peptide IIB stained most neuronal cells. In bovine cryosections, glial staining was also observed. In contrast, anti-peptide IIA and anti-platelet myosin antibodies primarily stained blood vessels. In bovine aorta, the anti-peptide antibodies recognized four bands, MIIB3, MIIB4, MIIA1, and MIIA2. Only MIIA2 was recognized by anti-human platelet myosin antibodies. In bovine aorta cryosections, anti-peptide IIB stained smooth muscle cells in tunica intima and tunica media but did not stain endothelial cells. Anti-peptide IIA stained smooth muscle cells in the tunica media, and endothelial cells of vaso vasorum but not of aorta. Only polyclonal anti-platelet myosin antibodies stained the endothelial cells of aorta tunica intima. These results indicate that multiple isoforms of cellular myosins exist in mammals, that these isoforms are expressed in a cell specific manner, and that the major myosin isoforms isolated from whole brain originate from neurons and, at least in bovine brain, from glia, but not from blood vessels.

Amino Acid Sequence↗