Biomedical subjects

N Murakami

Publications and source records attributed to N Murakami.

At least 271 records · Page 15Linked to original sources

PubMed1994

Basic fibroblast growth factor messenger RNA is expressed strongly at the acute stage of cerebral contusion.

Basic fibroblast growth factor (bFGF) has a neurotrophic effect both in vitro and in vivo, and is considered to play an important role in the maintenance of neuronal functions in the normal brain. Neural damage in brain contusion progresses after the primary injury of trauma because of cerebral hemodynamic and metabolic impairment including intracranial hemorrhage and/or brain swelling. Northern blot analysis of bFGF mRNA was performed in rats after cerebral contusion produced by our modified fluid percussion device. Expression of bFGF mRNA increased significantly on the second day after trauma. A possible role of bFGF is functioning to protect the critical neurons from secondary neural damage in cerebral contusion.

Actins↗

PubMed1994

A modified fluid percussion device.

This report examines a modified fluid percussion device with specific improvements made to address deficiencies found in previously reported devices. These improvements include the use of a cylindrical saline reservoir made of stainless steel, placement of the reservoir in a 15-degree head-up position for the easy release of air bubbles, placement of the fluid flushing outlet and the pressure transducer close to the piston on the same plane, with both perpendicular to the direction of the piston, and adjustable reservoir volume to vary the waveform of the pressure pulse, and a metallic central injury screw secured to the animal's skull over the exposed dura. Using this device, midline fluid percussion (MFP) and lateral fluid percussion (LFP) injuries were performed in 70 rats. Histopathologic findings included diffuse axonal injury in the MFP model and cortical contusion in the LFP model. Survival rate was 41.4% in MFP animals and 100% in LFM animals when the device settings were 178 mm3 of the cylindrical reservoir and 50 degrees-60 degrees in height of the pendulum. Our results suggest that this modified fluid percussion device may offer significant improvements over previously reported fluid percussion models for use in experimental head injury.

Animals↗

PubMed1994

Determination of plasma tissue factor antigen and its clinical significance.

To investigate the clinical significance of determination of plasma tissue factor (TF) antigen, we have developed a highly sensitive enzyme-linked immunosorbent assay (ELISA) for plasma TF, using two different monoclonal antibodies against TF apoprotein, 6B4 (catching antibody) and 5G9 (detecting antibody), and tetramethyl benzidine/H2O2 as substrates. Titration curves of recombinant human TF in buffer containing Triton X-100 were linear within the range from 50 to 2000 pg/ml. The total assay time was 3 h. Ultracentrifugation and immunoblot analysis indicated that human plasma and urine contained 50,000 g sedimentable and non-sedimentable forms of TF, both of which were detected by our ELISA method. Plasma and urine concentrations of TF in healthy subjects and patients with various diseases were measured by the ELISA method. In healthy subjects, plasma and urinary TF levels were found to be 149 +/- 72 pg/ml (n = 30) and 175 +/- 60 pg TF/urine creatinine mg (n = 95), respectively. TF was increased in plasma of patients with disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura, vasculitis associated with collagen diseases, diabetic microangiopathy and chronic renal failure receiving haemodialysis, but not in the plasma of endotoxaemic patients without DIC. The plasma TF/serum creatinine ratio did not show a positive correlation. Measurement of TF antigen in plasma may be useful for evaluating the endothelial damage and cell destruction in TF-containing tissues.

Adult↗

PubMed1994

Effect of thyroid-stimulating hormone on cultured thyrocytes obtained from patients with Graves' disease and inhibitive effect by sodium iodide: a functional study.

Thyrocytes obtained from patients with Graves' disease were cultured for 3 days. This was followed by culture with 10 mU/mL thyroid stimulating hormone (TSH) (TSH group), TSH and sodium iodide (Nal group), or without (control group) for 3 additional days. On the 8th culture day, the amounts of intra- and extra-cellular cyclic adenosine monophosphate (cAMP), extracellular cAMP and thyroglobulin (TG), peroxidase (PO) activity, and cell numbers were measured. The amounts of intra- and extra-cellular cAMP correlated well. TSH increased the values of cAMP, TG and PO to levels higher than those of the control group. As the amount of Nal added to the medium increased, these values decreased. Addition of 10(-5) mol/L Nal lowered the value of cAMP only. When 10(-4) mol/L Nal was added, these three levels were lower than those of the TSH group and the value of cAMP was almost equal to that of the control group. On cell number, no difference was found between the cells cultured with TSH, TSH and Nal, and without TSH or Nal. When the thyrocytes were cultured with 1 mmol/L dibutyryl cAMP sodium salt or 8-bromoadenosine 3',5'-cyclic monophosphate instead of TSH, 10(-4) mol/L Nal did not lower the values of thyroglobulin and peroxidase activity. These results suggest that the Nal blocks the intracellular signal transduction provoked by TSH, only at the cAMP production level.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1994

A case of non-tuberculous mycobacterial lymphadenitis diagnosed with new skin tests and PCR.

Non-tuberculous mycobacterial (NTM) cervical lymphadenitis has been rarely reported in Japan. We report on a case of a 15 month old child with NTM cervical lymphadenitis who was diagnosed with new skin tests containing NTM antigens and a polymerase chain reaction (PCR) method. These two diagnostic methods were highly useful in the present case, therefore we anticipate they will become available to other Japanese physicians to expedite the diagnosis of NTM lymphadenitis.

Humans↗

PubMed1994

Relationship between mean arterial pressure and muscle cell pH during forearm ischaemia after sustained handgrip.

Recent evidence suggests that there is a close correlation between the physiological responses to muscle chemoreflex and the decrease in intracellular pH during ischaemia after handgrip. This study evaluated whether the relationship is linear or has an apparent threshold. We measured muscle cellular pH through phosphorous nuclear magnetic resonance spectroscopy (31P-NMR), mean arterial blood pressure (MAP) and heart rate (HR) during ischaemia after sustained handgrip exercise at 50% of maximum voluntary contraction (MVC). Contraction was sustained for 15, 30, 45 and 60 s, followed by 2 min of circulatory arrest, respectively. Muscular pH during the ischaemia decreased linearly with increasing contraction time, from the base-line level of 7.11 +/- 0.03 units (U) to 6.98 +/- 0.03, 6.90 +/- 0.04, 6.72 +/- 0.06 and 6.54 +/- 0.06 U after 15-, 30, 45-, and 60-s contractions, respectively. The MAP was 86 +/- 2 mmHg at rest and did not change during the ischaemia after 15- and 30-s contractions. However, it significantly increased to 95 +/- 2 and 107 +/- 2 mmHg, after 45- and 60-s contractions, respectively. These data indicate that the relationship between MAP and pH is not a single linear relationship, showing one breaking point around the pH of 6.90 units. It suggests that the muscle chemoreflex has a clear threshold around 6.90 units of muscle pH, and below this pH, MAP increased linearly with decreasing muscle cellular pH.

Adolescent↗

PubMed1994

Extraocular muscles in Graves ophthalmopathy: usefulness of T2 relaxation time measurements.

PURPOSE: To determine if T2 relaxation time measurements with magnetic resonance (MR) imaging in patients with Graves ophthalmopathy (GO) can predict response to therapy. MATERIALS AND METHODS: Studied were 84 patients with GO, 27 with Graves disease without ophthalmopathy (GD), and 12 control subjects without Graves disease. T2 times of extraocular muscles and retrobulbar fat tissue were measured. Twenty-five patients with GO were treated with systemic corticosteroids and retroorbital radiation therapy. RESULTS: T2 relaxation times of muscles in patients with GD were the same as those in controls but were longer in patients with GO (P < .05). T2 times of fat in all patients were the same as those of the controls. The predicted probability of response to treatment increased with increased mean T2 relaxation times of extraocular muscles prior to therapy. Of the 25 patients with combined therapy, only those with particularly prolonged T2 relaxation times showed impressive response. CONCLUSIONS: T2 relaxation time measurements with MR allow noninvasive detection of acute muscle inflammation and predict which patients with GO will likely benefit from antiinflammatory therapy.

Adipose Tissue↗

PubMed1994

Effect of IL-1 receptor antagonist and antiserum to TNF-alpha on LPS-induced plasma ACTH and corticosterone rise in rats.

Using an antiserum against tumor necrosis factor (TNF)-alpha and an interleukin (IL-1) receptor antagonist, we studied putative roles of these cytokines in mediating the endotoxin-induced elevation of plasma adrenocorticotropic hormone (ACTH) and corticosterone levels in freely moving rats. Intravenous administration of Escherichia coli lipopolysaccharide (LPS) increased plasma ACTH and corticosterone levels in a dose-dependent manner. The plasma corticosterone reached to its highest level among a series of experiments after the administration of even the smallest dose (0.03 microgram/kg) tested. Plasma ACTH and corticosterone levels in these rats were completely inhibited by the intravenous administration of anti-murine TNF-alpha-rabbit antiserum (anti-TNFAS) after the administration of LPS but not by the intravenous administration of IL-1 receptor antagonist (IL-1RA). On the other hand, both recombinant human IL-1RA and anti-TNFAS significantly inhibited plasma ACTH increase stimulated with 10 micrograms/kg LPS. These findings indicate that 1) when the plasma corticosterone increase induced by intravenous LPS remains below its maximum, the effect is exclusively mediated by TNF-alpha, and 2) when a larger amount of LPS is administered, both IL-1 beta and TNF-alpha participate at least in part in the hypothalamic-pituitary-adrenal axis activation.

Adrenocorticotropic Hormone↗

PubMed1994

Enhancement of parasympathetic cardiac activity during activation of muscle metaboreflex in humans.

We measured the changes in heart rate (HR) variability estimated from the standard deviation of the R-R intervals to evaluate cardiac parasympathetic tone noninvasively before and during activation of muscle metaboreflex induced by postexercise muscle ischemia. Eight healthy male subjects performed sustained handgrip at 50% maximal voluntary contraction followed by forearm occlusion. Mean arterial pressure, cardiac stroke volume, and ratio of cardiac preejection period to left ventricular ejection time (PEP/LVET) were also measured. During the 2-min occlusion after 60 s of handgrip with voluntary respiration, HR variability and mean arterial pressure were significantly increased from baseline (54.4 +/- 6.1 to 80.1 +/- 12.8 ms and 81 +/- 1 to 99 +/- 3 mmHg, respectively) and PEP/LVET was decreased from resting level of 0.404 +/- 0.022 to 0.363 +/- 0.036. During occlusion and recovery, HR did not change from baseline level in any experiment. There was no influence of occlusion itself or of cessation of exercise per se on any parameters. Although overall enhanced HR variability was seen, probably due to lower breathing frequency and larger tidal volume, similar results were also obtained from an experiment with controlled respiration, showing that the increase in HR variability was not due to the changes in tidal volume or breathing frequency during occlusion. In conclusion, the HR variability is increased during activation of the muscle metaboreflex induced by postexercise muscle ischemia in humans. This finding shows that the parasympathetic cardiac tone is enhanced during activation of the muscle metaboreflex in humans and balances enhanced cardiac sympathetic activity to result in an unchanged HR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Mechanism of an early lysis by fatty acids from axenic Phormidium tenue (musty odor-producing cyanobacterium) and its growth prolongation by bacteria.

We have previously demonstrated that bacteria-containing Phormidium tenue, a cyanobacterium which produces musty odor 2-methylisoborneol, grew beyond 8 weeks, whereas axenic alga perished suddenly between the 3rd week and the 4th week while being cultured in the laboratory. This mechanism was investigated. It is assumed that when algal cells grow beyond a certain level, the supply of CO2 becomes inadequate and results in the rapid lysis of axenic alga. At that time, inhibitory substances liberated from algal cells kill the surviving alga. Since the process occurs continuously, this alga is finally annihilated. On the other hand, since inhibitory substances are metabolized or degraded by bacteria coexistent with alga, bacteria-containing P. tenue maintains growth for a long time. The growth-inhibitory substance was found to be unsaturated free fatty acids.

Bacteria↗

PubMed1994

Stomachic principles in ginger. III. An anti-ulcer principle, 6-gingesulfonic acid, and three monoacyldigalactosylglycerols, gingerglycolipids A, B, and C, from Zingiberis Rhizoma originating in Taiwan.

An anti-ulcer constituent, 6-gingesulfonic acid, and three monoacyldigalactosylglycerols, gingerglycolipids A, B, and C, were isolated from Zingiberis Rhizoma, the dried rhizome of Zingiber officinale Roscoe which was cultivated in Taiwan, together with (+)-angelicoidenol-2-O-beta-D-glucopyranoside. Based on chemical reactions and physicochemical evidence, the structures of 6-gingesulfonic acid, gingerglycolipids A, B, and C have been determined. In addition, the absolute stereostructure of (+)-angelicoidenol-2-O-beta-D-glucopyranoside was clarified on the basis of its synthesis from d-borneol. 6-Ginesulfonic acid showed weaker pungency and more potent anti-ulcer activity than 6-gingerol and 6-shogaol.

Animals↗

PubMed1994

Elatoside E, a new hypoglycemic principle from the root cortex of Aralia elata Seem.: structure-related hypoglycemic activity of oleanolic acid glycosides.

A new inhibitor named elatosides E (which was shown to affect the elevation of plasma glucose level by oral sugar tolerance test in rats) was isolated from the root cortex of Aralia elata Seem. together with elatoside F. The structures of elatosides E and F were elucidated on the basis of chemical and physicochemical evidence. The hypoglycemic activities of oleanolic acid and nine oleanolic acid glycosides obtained from the root cortex of Aralia elata have been examined, and some structure-activity relationships have been found.

Animals↗

PubMed1994

Escins-Ia, Ib, IIa, IIb, and IIIa, bioactive triterpene oligoglycosides from the seeds of Aesculus hippocastanum L.: their inhibitory effects on ethanol absorption and hypoglycemic activity on glucose tolerance test.

Five triterpene oligoglycosides named escins-Ia, Ib, IIa, IIb, and IIIa were isolated from the seeds of Aesculus hippocastanum L. and their chemical structures were determined on the basis of chemical and physicochemical evidence. Escins-Ia, Ib, IIa, and IIb were found to exhibit inhibitory effect on ethanol absorption and hypoglycemic activity on oral glucose tolerance test in rats. Among them, escins-IIa and IIb showed the higher activities for both bioassays, while desacylescins-I and II had no activity.

Animals↗

PubMed1994

Absolute stereostructures of hydramacrosides A and B, new bioactive secoiridoid glucoside complexes from the leaves of Hydrangea macrophylla Seringe var. thunbergii Makino.

Two new bioactive secoiridoid glucoside complexes named hydramacrosides A and B were isolated from the leaves of Hydrangea macrophylla SERINGE var. thunbergii MAKINO. The absolute stereostructures of hydramacrosides A and B were elucidated on the basis of chemical and physicochemical evidence which included the application of the 13C NMR glycosylation shift rule of 1, 1'-disaccharides and the modified Mosher's method. Hydramacrosides A and B exhibited inhibitory effect on the histamine release from rat mast cells induced by antigen-antibody reaction.

Animals↗

PubMed1994

Crude drugs from aquatic plants. IV. On the constituents of alismatis rhizoma. (2). Stereostructures of bioactive sesquiterpenes, alismol, alismoxide, orientalols A, B, and C, from Chinese alismatis rhizoma.

Following the characterization of the triterpene constituents in Chinese Alismatis Rhizoma, we investigated the chemical structures of orientalols A, B, and C, isolated from the less polar fraction of the crude drug together with two known sesquiterpenes, alismol and alismoxide. On the basis of the chemical and physicochemical evidence, the structures of orientalols A, B, and C have been determined and those of alismol and alismoxide were revised. All five sesquiterpenes were found to show an inhibitory effect on the contraction of isolated bladder smooth muscle induced by carbachol.

Animals↗

PubMed1994

Development of bioactive functions in hydrangeae dulcis folium. III. On the antiallergic and antimicrobial principles of hydrangeae dulcis folium. (1). Thunberginols A, B, and F.

From the less polar fraction of Hydrangeae Dulcis Folium, the fermented and dried leaves of Hydrangea macrophylla Seringe var. thunbergii Makino, Eight antiallergic and antimicrobial principles were isolated together with several known compounds. Among the newly isolated bioactive constituents, the chemical structures of thunberginols A, B, and F have been determined on the basis of chemical and physicochemical evidence. Thunberginols A, B, and F were found to exhibit more potent antiallergic activity than phyllodulcin, hydrangenol, disodium cromoglycate (DSCG), and tranilast. In addition, these thunberginols showed antimicrobial activity against oral bacteria.

Animals↗

PubMed1994

Studies on chemical modification of monensin. V. Synthesis, sodium ion permeability, antibacterial activity, and crystal structure of 7-O-(4-substituted benzyl)monensins.

7-O-(4-Substituted benzyl)monensins (3a-g) were synthesized from monensin (1), and their lipophilicity, antibacterial activity, and Na+ ion permeability were examined. 7-O-(4-Ethylbenzyl)monensin (3e) showed the largest Na+ ion permeability, but 3c,f,g showed smaller Na+ ion permeability than 7-O-benzylmonensin (2) in spite of higher lipophilicity. An X-ray study of the sodium salt of 3e revealed that the benzyl group was located over the position between the D and E rings, and that the ethyl substituent on the benzyl group was close to the C(28) methyl group on the E ring.

Anti-Bacterial Agents↗

PubMed1994

Crude drugs from aquatic plants. V. On the constituents of alismatis rhizoma. (3). Stereostructures of water-soluble bioactive sesquiterpenes, sulfoorientalols a, b, c, and d, from Chinese alismatis rhizoma.

From the water-soluble portion of Chinese Alismatis Rhizoma, four bioactive sesquiterpenes, sulfoorientalols a, b, c, and d, were isolated and their structures having a sulfonic acid function were established on the basis of chemical and physicochemical evidence. In addition, two sulfoorientalol congeners were derived from alismol by sulfonation of the exo-methylene moiety. Sulfoorientalols and the synthetic congeners were found to inhibit the carbachol-induced contraction of isolated bladder smooth muscle of guinea pig.

Animals↗