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Biomedical subjects

S Ando

Publications and source records attributed to S Ando.

At least 181 records · Page 10Linked to original sources
PubMed1995

Comparison of candoxatril and atrial natriuretic factor in healthy men. Effects on hemodynamics, sympathetic activity, heart rate variability, and endothelin.

The purpose of these experiments was to compare the effects of endopeptidase inhibition with oral candoxatril on systemic and forearm hemodynamics and muscle sympathetic nerve activity with responses to a low-dose atrial natriuretic factor infusion. Eleven healthy men received at random on three separate days either intravenous saline, natriuretic factor (1.6 pmol/kg per minute) plus saline, or oral candoxatril (200 mg) plus saline. Measurements were made at baseline and 30, 60, and 90 minutes after interventions. Atrial natriuretic factor lowered diastolic pressure (P < .01), central venous pressure (P < .001), forearm blood flow (P < .05), and forearm vascular compliance (P < .05) but had no effect on systolic pressure, heart rate or its variability, stroke volume, sympathetic nerve activity, plasma norepinephrine, or endothelin-1. Plasma epinephrine increased (P < .01). Candoxatril lowered central venous pressure (P < .001) and increased systolic pressure (from 116 +/- 6 to 120 +/- 7 mm Hg; P < .05), endothelin (from 4.6 +/- 1.1 to 6.8 +/- 3.2 pmol/L; P < .02), and epinephrine (P < .05), without affecting any other variables. Candoxatril and atrial natriuretic factor lowered central venous pressure in healthy men without causing a reflex increase in sympathetic nerve activity or norepinephrine, yet epinephrine rose. This suggests that both interventions may specifically inhibit sympathetic nerve traffic to muscle at physiological plasma atrial natriuretic factor concentrations. However, whereas the peptide lowered blood pressure, candoxatril increased systolic pressure. These contrasting hemodynamic responses may be related to differences in plasma atrial natriuretic peptide concentration and to altered endothelin metabolism by candoxatril.

Administration, Oral↗
PubMed1995

Tocopherol levels in the plasma lipoproteins from Japanese eel Anguilla japonica.

The alpha- and gamma-tocopherol levels in the plasma of Japanese eel (Anguilla japonica) were 53.9 micrograms and 1.3 micrograms/ml of plasma, respectively. The alpha-tocopherol in the plasma was mainly distributed as very-low-density lipoprotein and low-density lipoprotein (LDL), while LDL and high-density lipoprotein constituted most of the gamma-tocopherol. A highly positive coefficient of correlation was observed between the alpha-tocopherol and lipoprotein contents in Japanese eel plasma.

Anguilla↗
PubMed1995

[Successful combination therapy of cyclosporine and steroids in two cases with interstitial pneumonitis associated with polymyositis].

Cyclosporine is an immunosuppressive agent which is well-established in the transplantation of organs including kidney, liver and bone marrow. It acts by inhibiting the production of interleukin 2, thereby blocking both the development of cytotoxic lymphocytes, and the proliferation of helper T cells. T cell-mediated muscle damage is thought to be important in the pathogenesis of polymyositis. And activated cytotoxic T cells are thought to play an important role of polymyositis/dermatomyositis with active pneumonitis. It is thereby likely that cyclosporine would be effective in the management of polymyositis with interstitial pneumonitis. We have used cyclosporine in two cases of corticosteroids resistant polymyositis associated with pneumonitis. The first case was admitted because of the relapse of polymyositis. She was partially responded by the high dose of steroid, but showed decreased %DLCO and increased AaDO2 during the therapy. And oral cyclosporine was given with steroid. Within two weeks, serum creatinine kinase level was reduced to normal range, and the improvement of pneumonitis was observed. The second case was admitted because of the flare of pneumonitis. She was treated with high dose of steroid with insufficient response. And cyclosporine was prescribed. Within two weeks of treatment, her symptom was relieved, and blood gas analysis showed an improvement of pulmonary function. And steroid could be tapered. In both cases, the initial dose of cyclosporine was 200 mg/day, and the optimal trough level was thought to be ranged 100 to 150 ng/ml. In the second case, renal dysfunction was observed but it was recovered by the reduction of the dose of cyclosporine. No other side effect was appeared.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclosporins↗
PubMed1995

[Effects of temperature and humidity on the stability of nitric oxide, and efficacy of soda lime as a selective absorber of nitrogen dioxide].

Although inhaled nitric oxide (NO) has attracted attention as a pulmonary vasodilator, little heed has been given to its potential toxicity. Nitric oxide is known to be rapidly oxidized to nitrogen dioxide (NO2), which may damage pulmonary tissue. We examined the effects of temperature and humidity on the production of NO2 from NO. We also evaluated the amount of NO2 absorbed by soda lime, which is usually placed in the inspiratory line. For this purpose, we measured changes over time in the concentrations of NO and NO2 in mixtures that included NO, oxygen, and nitrogen in various concentrations, and at different temperatures and humidities. We confirmed that the formation of NO2 from NO follows the equation: -d[NO]/dt = 2 k[NO]2 [O2], where k is the rate constant. We found that k was significantly smaller at 37 degrees C than at 25 degrees C but was not influenced by humidity (0%, 40% or 90%). Although soda lime was very effective in absorbing NO2 from the inspiratory line, NO was simultaneously absorbed at the same molar ratio when the two gases existed together in the line. We thus conclude that inhalation of NO at 37 degrees C is more desirable than inhalation at room temperature, to suppress the production of NO2. When soda lime is used in the inspiratory line, attention should be paid to the reduction in the concentration of NO in the line.

Absorption↗
PubMed1994

Decreased synaptic density in aged brains and its prevention by rearing under enriched environment as revealed by synaptophysin contents.

Changes in synaptic density in various brain regions were assessed among different age groups of rats maintained in ordinary small cages, as determined by synaptophysin assay. The synaptophysin content in hippocampus decreases as early as in the adult stage. The most remarkable decrement occurs in occipital cortex. In other regions, synaptophysin contents decrease in senescence to 60-77% of the respective peak values during young and adult stages. The other rat group reared under enriched environment in a large cage until 30 months of age was examined for synaptic density, and was revealed to maintain the similar levels as in young, or even higher levels in frontal, temporal, entorhinal cortices and hippocampus. These results indicate that the synaptic density in cerebrum decreases in senescence and this decrease can be prevented by rearing under enriched environment.

Aging↗
PubMed1994

Cerebellar infarctions secondary to cranio-cervical anomalies: a case report.

We report a case of cerebellar infarctions which occurred in the territories of the bilateral posterior inferior cerebellar arteries. This case was complicated with cranio-cervical anomalies composed of assimilation of the atlas, atlanto-axial dislocation, and basilar impression. The 40-year-old male patient had no detectable risk factors predisposing to atherosclerotic arterial occlusion or cardiogenic embolism, and there were no angiographic findings of atherosclerosis. It was, therefore, postulated that the cerebellar infarctions were secondary to those cranio-cervical anomalies. The developing mechanism is discussed.

Adult↗
PubMed1994

Characteristics of gangliosides including O-acetylated species in growth cone membranes at several developmental stages in rat forebrain.

Growth cones, the motile tips of extending neuronal processes, are involved in accurate synaptogenesis. To study the developmental changes in ganglioside composition including O-acetylated gangliosides in growth cones, we analyzed the gangliosides in growth cone membranes (GCM) prepared from rat forebrains at different developmental stages. At several stages, GCM contained significantly larger amounts of gangliosides than the other membrane subfractions. The ganglioside content of GCM increased in amount with development. Moreover, in GCM, the relative amount of GD3 gradually decreased, and that of GD1a dramatically increased. There were significant differences in the composition of ganglioside species between GCM and the perinuclear plasma membrane subfraction (NM); most importantly, GCM had a higher ratio of GD1a to GM3 plus GD3 than NM. There were three different O-acetylated gangliosides in GCM: O-acetyl-GD3, O-acetyl-GT1b, and O-acetyl-GQ1b. The molar ratio of O-acetyl-GD3 decreased in GCM at later stages (5% of the total gangliosides at embryonic day 17, to 1% at postnatal day 5). However, those of the other two O-acetylated gangliosides were almost constant (1-2% of the total). Our results show that there are significant differences in ganglioside content and composition between the membrane subfraction of growth cones and the perinuclear portion. This suggests that several species of gangliosides, including O-acetyl-GD3, play a role in growth cone function.

Acetylation↗
PubMed1994

Mediation of the physiological response of platelets by interactions of spectrin and protein 4.1 with the cytoskeleton.

Spectrin and protein 4.1 became associated with the Triton-insoluble cytoskeletons during platelet activation. Inhibition of platelet activation by a PGI2 analogue resulted in release of the proteins from the cytoskeletons. Changes in subcellular distributions of the proteins preceded changes in the state of platelet aggregation. These results suggest that interactions of spectrin and protein 4.1 with the cytoskeletons are involved in mediating the physiological response of the platelet.

Actins↗
PubMed1994

N-acetylgalactosaminyl GD1a is a target molecule for serum antibody in Guillain-Barré syndrome.

Serum antibodies against such major glycolipids as GM1, GD1b, and LM1 have been reported in patients in the acute phase of Guillain-Barré syndrome (GBS). Because minor unidentified glycolipids also may be targets of antibodies in GBS sera, we assayed serum antibody against a crude ganglioside fraction using thin-layer chromatogram immunostaining. Antibody activity was detected against a band that migrated just below GD1a in 6 of the 50 patients with GBS tested. Antibody titer, as determined by enzyme-linked immunosorbent assay, decreased during the course of the disease. All 6 patients had suffered gastrointestinal infection before the neurological onset of GBS and showed low amplitudes for the compound muscle action potentials and normal or only slightly decreased nerve conduction velocities. Thin-layer chromatogram immunostaining did not show this antibody activity in any of the 16 normal and 119 disease controls. The unidentified glycolipid was isolated by DEAE-Sephadex A-25 column chromatography, sialidase treatment, and Iatrobeads column chromatography. Fast atom bombardment-mass spectra showed it to be N-acetyl-galactosaminyl GD1a.

Adult↗
PubMed1994

Facile methods for isolation and determination of gangliosides in a small scale: age-related changes of gangliosides in mouse brain synaptic plasma membranes.

A quantitative isolation method for gangliosides from small sizes of samples has been developed. Total lipids were separated into gangliosides and other lipids using Phenyl Sepharose column chromatography. Gangliosides were recovered in a yield of 99%. Determination of gangliosides was performed by gas chromatography--mass spectrometry using a selected ion-monitoring technique. These combined methods can provide quantitative isolation and determination of gangliosides from as little as 10 mg fresh brain tissues or 0.5 mg protein of membrane fractions. The present methods were successfully applied to the analysis of gangliosides from mouse brain synaptic plasma membranes to reveal that the ganglioside contents and composition remain constant from adult to senescence.

Aging↗
PubMed1994

Postganglionic sympathetic nerve discharges can contain both central and pulse-related oscillations simultaneously in rabbits.

We examined whether modulation of sympathetic nerve discharges (SND) by changes in carotid sinus pressure (CSP) is influenced by the pattern of the rhythm of central sympathetic neurons and whether the rhythm of the sympathetic nerve derived from central sympathetic neurons and that from the inputs from baroreceptors can coexist in postganglionic renal SND. In alpha-chloralose-anesthetized rabbits with aortic denervation and vagotomy, firing of central sympathetic neurons was at first left spontaneous and then driven artificially at 3 Hz by peroneal nerve stimulation. Under these conditions, renal SND were recorded and compared while CSP was altered at low frequencies. When central sympathetic neurons were firing spontaneously and low frequency oscillation was applied to CSP, two kinds of oscillation were noted in SND; first oscillation at the same frequency as that of central sympathetic neurons, and second oscillation of CSP changes. Power spectra of SND also showed two peaks at these two oscillations. When central sympathetic neurons regularly discharged at 3 Hz by electrical stimulation and CSP was kept constant, the power spectra of SND had a discrete single peak at 3 Hz. When a regular oscillation was applied to CSP at 1 Hz, the amplitude of central sympathetic outflow at 3 Hz was modulated at 1 Hz without disturbance of the frequency of the central 3 Hz rhythm. In other words, two apparently different rhythms coexisted in SND. In the power spectra, two discrete peaks were noted at the frequency of CSP changes and at the central sympathetic oscillation. When SND were averaged by CSP-triggered summation during spontaneous or artificial 3 Hz central firing, it was revealed that the shape of these two averaged SND were completely same in spite of obviously different central firing patterns. Nadir of SND occurred about 400 ms after the peak of CSP during changes in CSP at several frequencies in these two conditions. Thus, these results indicated two points; (1) CSP changes modulate the amplitude of SND in the same manner irrespective of the frequency or pattern of discharge of central sympathetic neurons; (2) both of frequency components of SND induced by oscillatory changes in central sympathetic neurons and oscillatory inhibitory input from baroreceptors can coexist even if their frequencies were different.

Action Potentials↗
PubMed1994

Identification of phosphorylation sites on glial fibrillary acidic protein for cdc2 kinase and Ca(2+)-calmodulin-dependent protein kinase II.

We identified the phosphorylation sites of glial fibrillary acidic protein (GFAP) for cdc2 kinase and Ca(2+)-calmodulin (CaM)-dependent protein kinase II. GFAP was phosphorylated to approximately 0.2 mol of phosphate/mol of GFAP by cdc2 kinase, and this phosphorylation did not induce disassembly of the filament structure. On the other hand, GFAP was phosphorylated to approximately 1.9 mol of phosphate/mol of GFAP by Ca(2+)-CaM-dependent protein kinase II, and this phosphorylation did induce disassembly of the filament. Sequential analysis of the purified phosphopeptides revealed that only Ser8 on GFAP was phosphorylated by cdc2 kinase, whereas Ser13, Ser17, Ser34, and Ser389 on GFAP were phosphorylated by Ca(2+)-CaM-dependent protein kinase II.

Amino Acid Sequence↗
PubMed1994

Detection of human immunodeficiency virus-1 nucleic acid on inactivated filter paper disks by polymerase chain reaction and microtiter plate assay.

Human immunodeficiency virus type 1 (HIV-1) in cultured cells, peripheral blood samples and sera were adsorbed on filter paper disks and inactivated by heat or ethanol. Two procedures, the polymerase chain reaction (PCR) and microtiter plate assay (HMPA) were used to detect the nucleic acid. The sensitivity after different heat treatments with nested PCR for HIV-1 DNA (or nested reverse transcription-PCR for HIV-1 RNA) was identical regardless of whether the samples were examined immediately or one month later. Inactivation by ethanol treatment resulted in a slight loss of sensitivity. The HMPA proved to be as reliable and specific as the conventional PCR technique. We conclude that the heat-treated filter paper disk assay is suitable for identifying HIV nucleic acid in clinical samples sent to the laboratory from a distance, e.g. in an envelope.

Base Sequence↗
PubMed1994

Analysis of the uveitogenic determinant in repeat structure of retinal interphotoreceptor retinoid-binding protein (IRBP).

IRBP is a glycolipoprotein with a four-fold partially homologous repeat structure approximately 300 residues in length, and is one of the retinal antigens capable of inducing experimental autoimmune uveoretinitis (EAU) in susceptible animals by their active immunization. The most immunopathogenic peptide of bovine IRBP for EAU in Lewis rats is reported to be the sequence 1169-1191 (PTARSVGAADGSSWEGVGVVPDV) with two immunogenic motifs common to T cell epitopes (underlined). The uveitogenic site of peptide 1169-1191 was localized at the carboxyl terminus (peptide 1182-1191) and not at the amino acid terminus (peptide 1169-1182). Repeat peptides of sequence 1179-1191 containing the four homologous residues (1182W, 1186G, 1187V and 1189P), that is the peptides 271-283, 579-591 and 880-892, all elicited EAU. Peptide 579-591 could not stimulate proliferation of lymphocytes from rats immunized with IRBP, but had the capacity to adoptively transfer EAU. The role of the homologous residues was examined using analogues of the uveitogenic peptide 1182-1194, in which each homologous residue was substituted by glycine (G) or leucine (L) (1182W-->G, 1186G-->L, 1187V-->G, and 1189P-->G). One analogue (1186G-->L) strongly diminished the ability to induce EAU, while the other three analogues completely abolished the ability, indicating that these homologous residues were essential for the induction of EAU. In addition, the uveitogenic peptides tested in this study were found not to contain the major epitope for antibody production.

Amino Acid Sequence↗
PubMed1994

Transfer function analysis from arterial baroreceptor afferent activity to renal nerve activity in rabbits.

In vagotomized and anesthetized rabbits, aortic pressure (AP), aortic depressor nerve activity (ANA), and renal sympathetic nerve activity (RNA) were simultaneously measured while perturbing AP randomly. To quantitatively characterize the role of the arterial baroreflex system in generating RNA, we determined the transfer function (TF) of the central baroreflex arc from ANA to RNA in the frequency domain (0.02-5 Hz). The magnitude of squared coherence was > 0.5, the phase was close to -180 degrees, and the gain of TF was flat over 0.02-0.3 Hz, indicating that changes in RNA were linearly and instantaneously but inversely related to changes in ANA over this frequency range. Above 0.3 Hz, the coherence was low, suggesting that RNA unrelated to ANA existed in the frequency range. In animals without AP perturbations, power spectrum of RNA resided over 0.2-5 Hz with a broad peak at 1 Hz, which may represent central activity. Our results suggest that over 0.02-0.3 Hz the relationship between arterial baroreceptor afferent nerve activity and RNA is linear and instantaneous but above 0.3 Hz it is not linear possibly due to an interaction between central activity and arterial baroreflex.

Afferent Pathways↗
PubMed1994

Effects of L-arginine on impaired acetylcholine-induced and ischemic vasodilation of the forearm in patients with heart failure.

BACKGROUND: Endothelium-dependent vasodilation in response to acetylcholine (ACh) and ischemic vasodilation during reactive hyperemia are attenuated in the forearm of patients with heart failure (HF). It has been shown that L-arginine augments endothelium-dependent vasodilation in healthy subjects. Thus, the aim of the present study was to determine if L-arginine improves endothelium-dependent and ischemic vasodilation in the forearm in HF. METHODS AND RESULTS: Forearm blood flow was measured by a strain-gauge plethysmograph in 20 patients with HF and in 24 age-matched control subjects (C). Resting forearm vascular resistance (FVR) was significantly higher in HF than in C (37 +/- 4 versus 22 +/- 2 U, P < .01). Intra-arterial infusions of ACh or sodium nitroprusside (SNP) at graded doses progressively decreased FVR in HF as well as in C. The magnitude of ACh-induced vasodilation was attenuated in HF (P < .01), whereas SNP-induced vasodilation was similar between the two groups. The minimal FVR during reactive hyperemia after 10 minutes of arterial occlusion was significantly higher in HF (n = 12) than in C (n = 12) (3.2 +/- 0.4 versus 2.1 +/- 0.1 U, P < .05). L-Arginine significantly augmented maximal vasodilation evoked with ACh and decreased minimal FVR during reactive hyperemia in HF (P < .01) but not in C. L-Arginine did not affect SNP-induced vasodilation in HF or C. CONCLUSIONS: Our results suggest that defective endothelial function may contribute to impaired ischemic vasodilator capacity in HF.

Acetylcholine↗