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Biomedical subjects

N Iida

Publications and source records attributed to N Iida.

At least 127 records · Page 7Linked to original sources
PubMed1986

Mammalian kidney lectin.

Lectins that agglutinate intact red blood cells of rabbit, and their endogenous inhibitors, were found in extracts of cow, pig, rat, and human kidneys. Lectins were separated from inhibitors by gel chromatography on a column of Toyopearl HW-75. Adsorption tests with immobilized glycoconjugates and ion-exchange gels revealed that the bovine kidney lectin binds with sialylglycoproteins by sugar-specific interactions but not by nonspecific, electrostatic interactions. The results of the hemagglutination-inhibition tests showed that all of the endogenous inhibitor fractions were active toward all renal lectins tested, and that glycoproteins having sialyl residues, and also heparin, are also good inhibitors of the lectins. However, the hemagglutination-inhibitory activity of human urinary Tamm-Horsfall glycoproteins varied from source to source, and that having the highest inhibitory activity did not always have the highest content of sialic acids. Crude bovine kidney lectin was further purified by ion-exchange chromatography on DEAE-Sephadex A-50. Analysis by SDS-polyacrylamide gel electrophoresis showed that the purified lectin consists of a approximately 63,000 daltons subunit.

Agglutination↗
PubMed1986

Carbohydrate-binding specificity of silkworm lectin.

The binding specificity of a lectin from the hemolymph of silkworm larvae was examined quantitatively by taking advantage of the fluorospectrophotometric properties of the lectin. On excitation at 280 nm, the lectin fraction gave a fluorescence-emission spectrum centered at 336 nm, which was attributable to tryptophan residues. The fluorescence could be completely quenched by the addition of specific saccharides. The affinity constants of the silkworm lectin with specific saccharides were calculated from the changes in intensities of fluorescence-difference spectra induced by the saccharides. The silkworm lectin had the highest affinity for dermatan sulfate and hyaluronic acid, followed by protuberic acid, heparin, and chondroitin sulfate A. Among monosaccharides tested, only D-glucuronic acid and N-acetyl-neuraminic acid induced weak but significant quenching, and their affinity constants were found to be low. These results indicate that the silkworm lectin has a strong affinity for carboxyl groups, especially alpha-L-iduronic acid residues, in the saccharides. In most cases, sulfate groups on the saccharides interfere with the specific interactions.

Animals↗
PubMed1986

Comparative effects of nicardipine, a new calcium antagonist, on size of myocardial infarction after coronary artery occlusion in dogs.

To examine whether nicardipine, a dihydropyridine derivative, limits size of myocardial infarction, and to compare the protective effects of nicardipine administered before and early and late after coronary artery occlusion, 99mTc-labeled albumin microspheres were injected into the left atrium during 5 min temporary coronary artery occlusion to determine the extent of the hypoperfused zone (the area at risk). The coronary arteries were then reperfused for 45 min before 6 hr permanent coronary artery occlusion. Fifteen minutes before permanent occlusion, dogs were randomly assigned to a control group (n = 11), a pretreatment group (n = 9), which received at this point 10 micrograms/kg of nicardipine as a loading dose followed by a continuous infusion of 8 micrograms/kg/hr for 6 hr, an early treatment group (n = 9), in which nicardipine treatment was initiated 15 min after occlusion, or a late treatment group (n = 8), in which nicardipine administration was delayed for 3 hr. Six hours after coronary artery occlusion, the hearts were excised and the left ventricle of each was cut into 3 mm thick slices and stained with triphenyltetrazolium chloride. The extent of myocardial necrosis was measured by planimetry of the unstained areas. Thereafter, the same slices were autoradiographed and the extent of the hypoperfused zone was measured by planimetry of the "cold spot." The extent of the hypoperfused zone was identical among the four groups. In the control group, the ratio of the extent of myocardial necrosis to the extent of the hypoperfused zone was 95.8 +/- 3.8% (mean +/- SEM). However, it was significantly smaller in the pretreatment group (59.9 +/- 13.3%, p less than .05) and the early treatment group (49.0 +/- 10.6%, p less than .01) than in the control group. In the late treatment group, this value was not different from that in the control group (86.5 +/- 7.1%). There was a close inverse correlation between reduction of infarct size and the extent of the hypoperfused zone in the pretreatment and early treatment groups. Thus, nicardipine administered before or early after coronary artery occlusion limited infarct size by 37% to 49%, whereas when administration was delayed for 3 hr infarct size was not reduced. Furthermore, nicardipine had more striking effects on the ischemic myocardium of dogs with small hypoperfused zones than on that of dogs with large hypoperfused zones.

Animals↗
PubMed1986

[Carotid-ophthalmic aneurysms and visual abnormalities].

The direct neck clipping for carotid-ophthalmic aneurysm is hazardous and difficult as compared with other intracranial aneurysms because of its location adjacent to the anterior clinoid process, the optic nerve, and the cavernous sinus. The authors discuss the visual abnormalities accompanied by carotid-ophthalmic aneurysm on the basis of our experiences with 30 patients with 33 aneurysms. Ten patients (4 of 14 with ruptured aneurysms, 6 of 16 intact aneurysms) had preoperative visual abnormalities. Of our series of patients, visual acuity and visual field were impaired in one eye. The most common field abnormalities were unilateral inner or upper side defects. In the patients whose aneurysms were intact, visual abnormalities had been slowly progressive over many months. Otherwise, 2 cases with ruptured aneurysm experienced their first visual symptoms at the same time their hemorrhage. According to the projection of aneurysm with respect to internal carotid artery, superomedial and posteromedial projections were common in the patients with visual abnormalities. Seven patients with visual dysfunctions were operated on. Improvement of the visual symptoms was observed in 3 cases. In these cases, complete collapse of the aneurysm with good decompression of the optic nerve was obtained at operation. Two patients deteriorated following surgery; this occurred in relation to attempts to clip the aneurysm neck directly, and optic nerve was probably excessively manipulated. Two patients had no change in visual symptom: one was treated with trapping of internal carotid artery combined with STA-MCA anastomosis, another had direct hemorrhage into the ipsilateral optic nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

EEG abnormalities in nonepileptic patients.

A total of 202 nonepileptic patients (120 males and 82 females) who exhibited spike abnormalities at least twice in their EEG examinations were studied. The incidence of spike abnormalities among nonepileptic patients was 8.1% (847/10,473). The majority (90%) were under age 19. Headache, dizziness and vomiting, and abdominal pain were more frequently observed compared with controls. Mild paroxysmal EEG abnormalities such as diffuse irregular slow wave bursts with spike (27%), positive spikes (25%) or small spike (8.4%) were commonly detected. In three patients who developed epileptic seizures during the follow-up period, more specific EEG abnormalities were often exhibited. Other factors like the age at onset before 9, characteristic clinical symptoms or a positive family history of seizures were confirmed to be necessary for the manifestation of clinical seizures.

Age Factors↗
PubMed1985

Ultra-high-strip-density radiographic grids: a new antiscatter technique for mammography.

We conducted a comprehensive study on the application of ultra-high-strip-density (UHSD) grids to mammography for the improvement of image contrast. These UHSD grids have strip densities of 70 to 100 lines/cm. After investigating the performance of mammographic grids with various design parameters through Monte Carlo simulation studies, we made prototypes of UHSD grids having lead strip thicknesses of 20 to 37 micron, aluminum interspacer thicknesses of 80 to 120 micron, and grid ratios of 2 to 6. The UHSD grids can be placed inside the cassette without a Bucky tray and thus will not increase geometric unsharpness. The measured physical characteristics and the phantom images obtained confirmed our findings in the simulation studies. A 40 to 90% increase in contrast was achieved at Bucky factors of 2 to 3.5; these results are comparable with those from conventional antiscatter grid techniques in mammography. The potential usefulness of the UHSD grids was demonstrated in a preliminary clinical comparison of mammograms.

Equipment Design↗
PubMed1985

Serum phosphate, parathyroid hormone and vitamin D metabolites in patients with chronic renal failure: effect of aluminum hydroxide administration.

Patients with chronic renal failure showed the existence of phosphate retention, secondary hyperparathyroidism, and reduced production of 1,25-(OH)2D. In order to determine the effect of correction of hyperphosphatemia on secondary hyperparathyroidism and vitamin D metabolism in those patients, 7 nondialyzed patients with chronic renal failure were treated with large doses of A1(OH)3 (15-18 g/day) to correct their high levels of serum phosphate. After treatment with A1(OH)3, serum phosphate fell significantly (p less than 0.005) from 6.3 +/- 1.3 (mean +/- SD) to 3.7 +/- 0.5 mg/dl. Serum parathyroid hormone decreased significantly (p less than 0.02) from 2.87 +/- 1.64 to 1.85 +/- 1.26 ngEq/ml. Serum 1,25-(OH)2D was low compared to the normal mean level before A1(OH)3 administration and decreased significantly (p greater than 0.02) from 19.4 +/- 6.1 to 11.4 +/- 4.3 pg/ml after the treatment. Aluminum levels increased significantly (p greater than 0.02) from 1.7 +/- 1.0 to 3.6 +/- 1.5 micrograms/dl. Serum calcium, calcitonin, and 25-(OH)D showed no significant change. Our data suggested that the suppression of secondary hyperparathyroidism by A1(OH)3 treatment results in a decrease of the 1,25-(OH)2D level in patients with chronic renal failure, even though their hyperphosphatemia has been corrected. We speculate that aluminum loading might play a role in diminishing the secretion of parathyroid hormone and the production of 1,25-(OH)2D in humans.

Adult↗
PubMed1985

Prominent negative U wave in variant angina pectoris.

The extremely prominent negative U wave occasionally appears during a cardiac attack in variant angina pectoris. The clinical profile of the negative U wave was therefore studied in 80 patients with variant angina pectoris (VA) and 33 controls with resting angina pectoris (RA). The prominent negative U wave appeared in 55 of the patients with VA (68.8% of patients) and in 10 of the patients with RA (30.3%); thus, there was a significant difference in the appearance of the wave between the 2 groups of patients (p less than 0.001). The leads in which the negative U wave appeared were mostly consistent with those in which the ST segment was elevated. The negative U wave began to appear at about the time when ST-segment elevation began to improve; the wave then gradually became very prominent and then eventually disappeared. The patients with VA and also those with RA on whose ECGs the negative U wave appeared during exercise testing also had negative U waves during spontaneous episodes of angina. An investigation of the frequency of appearance of ST deviation and negative U waves during exercise testing, regardless of the type of angina pectoris, disclosed that the negative U wave appeared in 14 of 20 patients with ST-segment elevation (70% of patients), while the negative U wave appeared in only 52 of 519 patients with either no ST change or ST-segment depression (10.4%); thus, there was a significant difference in the appearance of the negative U wave between these 2 groups (p less than 0.001). Coronary cinearteriography failed to disclose any apparent difference between the appearance of the negative U wave and the presence of stenosis. The prognosis of VA and RA in patients with negative U waves was less favorable compared to those without negative U waves. In particular, we noted that of the 10 patients with RA associated with negative U waves, 4 died. Although the mechanism of the negative U wave is not yet known, we believe that the above findings contribute to its elucidation.

Adult↗
PubMed1984

Dose-dependent pharmacokinetics of aprindine in healthy volunteers.

The disposition of aprindine following a single oral dose can best be described by a two-compartment open model. The mean plasma half-life (t 1/2 beta) increased from 8.0 +/- 2.1 h (SD) after a 25 mg dose of 9.4 +/- 2.9 h after 50 mg and to 15.8 +/- 2.6 h after 100 mg, with a decrease in total plasma clearance (Cl/F) and volume of distribution at steady state (V dss/F) and during beta-phase (V d beta/F). The area under plasma concentration-time curve (AUC), maximum plasma concentration (C max) and the amount of unchanged aprindine excreted in the urine increased in a non-linear fashion with the increase in dose. The t 1/2 beta after multiple oral doses showed a 3-fold increase over the single dose value. These results indicate that aprindine shows dose-dependent non-linear kinetics.

Adult↗
PubMed1984

Freeze-fracture of biological specimens prior to conductive staining.

Liver, kidney, spleen and other organs of the rat were fixed with glutaraldehyde, substituted with absolute ethanol or dimethyl sulfoxide (DMSO), freeze-fractured in liquid nitrogen, stained by the rapid tannin-osmium thiocarbohydrazide-osmium (TaOTO) method (staining with each agent for 10 min), critical-point-dried with liquid carbon dioxide, and observed with the scanning electron microscope. The absolute ethanol or DMSO freeze-fracture method provided flat fracture surfaces (without regard to cell boundaries) of the samples and allowed a good visualization of their inner structures. The fracture surfaces were suitably stained by the rapid TaOTO method, and could be scanned with no charging. Neither maked damage nor undesired dislocation of tissue elements was noted on the freeze-fractured and TaOTO-stained surfaces. This procedure, freeze-fracture prior to conductive staining, has an advantage of eliminating the bulk charging effects that tend to occur in specimens fractured after staining. When substituted with 75% DMSO aqueous solution, the samples spontaneously fractured without any need for razor blades. Fracture planes in this spontaneous fracture sometimes ran along the cell boundaries and allowed a clear visualization in the SEM of the enfaced surfaces of closely associated cells such as hepatocytes.

Animals↗
PubMed1983

Physical and clinical evaluation of new high-strip-density radiographic grids.

The imaging performance of new high-strip-density (HSD) grids having 57 lines/cm was compared with that of conventional low-strip-density (LSD) grids having 33 or 40 lines/cm. The unique advantage of HSD grids is that, under most standard radiographic conditions, the grid lines are not noticeable on the final image, even if the grid is stationary. This is due to the combined effect of the high fundamental spatial frequency of HSD grids, the modulation transfer function of screen-film systems and of the human visual system, and scattered radiation. Monte Carlo simulation studies, phantom images, and clinical evaluation indicate that HSD grids can provide contrast improvement factors and Bucky factors that are comparable to or slightly better than those obtained with LSD grids. Therefore, it may now be possible to eliminate moving Bucky trays from radiographic tables and fluoroscopic devices.

Bone and Bones↗
PubMed1983

Evaluation of effects of antiarrhythmics on ventricular premature contraction.

Although subjective symptoms and brief recording of ECG have been used for an efficacy evaluation of new antiarrhythmics on ventricular premature contraction (VPC), incidence of subjective complaints in VPC was under 25% and number of VPC for 3 min did not correlate enough to those for 24 hours, indicating these parameters are not appropriate for such a trial. Number of VPC automatically counted by DECG (continuous ECG recording for 24 hours) showed high accuracy, while day to day variation of VPC arose as the next problem. While cases of more than about 7,000/day showed very little day to day variation, cases of less than about 1,000/day had poor reproducibility, indicating that the former group can be used for the trials of new antiarrhythmics, but not the latter group. For cases with medium magnitude of VPC variation, DECG should be recorded twice during the period without drug administration and application of the paired t-test for number of VPC in each corresponding hour may bring a good evaluation.

Anti-Arrhythmia Agents↗