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M Okada

Publications and source records attributed to M Okada.

At least 1,081 records · Page 60Linked to original sources
PubMed1992

Intravitreal neovascular tissue of proliferative diabetic retinopathy: an immunohistochemical study.

Intravitreal neovascular tissue in 8 cases of proliferative diabetic retinopathy was investigated using immunohistochemical techniques. All 8 cases yielded positive immunoreactivity for type II collagen (vitreous collagen). The intravitreal neovascular tissue was classified into two groups (A or B), depending upon the distribution of type II collagen. In group A (3 cases), blood vessels were entirely surrounded by vitreous collagen, and in group B (5 cases), the vessels proliferated on one side of a mass of vitreous collagen. Type I and III collagens were distributed diffusely within the extracellular space of the tissue, whereas type IV collagen and fibronectin (FN) formed a basement membrane-like foundation for the newly formed vessels. Glial fibrillary acidic protein (GFAP)-immunoreactive cells were not clearly detected in any of the cases. Neovascular tissue typically proliferated on the posterior vitreous surface (as found in group B), but was also found to penetrate the vitreous gel (as found in group A). As neovascular tissue proliferation proceeded, types I, III and IV collagens and FN were produced. Glial cells (GFAP-positive cells) were not essential for neovascular tissue formation.

Animals↗
PubMed1992

Distinct responses of interleukin-6 and other laboratory parameters to treatment in a patient with polyarteritis nodosa--a case report.

The authors describe a patient in whom the serum levels of interleukin-6 (IL-6) and other laboratory parameters were monitored. The IL-6 and C-reactive protein (CRP) levels, which were extremely high before treatment, declined rapidly with administration of prednisolone. Rheumatoid factor, IgG, and platelets count declined more gradually. Thus, determination of the serum IL-6 level might be useful in diagnosing and monitoring polyarteritis nodosa.

Aged↗
PubMed1992

Reference values of serum and urine creatinine, and of creatinine clearance by a new enzymatic method.

A new, totally enzymatic procedure for the determination of creatinine in serum and urine, using creatinine amidohydrolase, creatine amidinohydrolase, sarcosine oxidase and formaldehyde dehydrogenase is described. The assay was adapted to a discontinuous analyser with each analysis requiring only 20 microL of serum or 3 microL of urine. Analytical recovery of creatinine in serum and urine averaged 100.6%. Within-run and between-run precision studies gave coefficients of variation of 1.1% and 1.8%, respectively, for a serum with mean values of 83 mumol/L (9.4 mg/L) creatinine. Creatinine concentrations in serum and urine were measured by this procedure, in Japanese children and adults. The reference intervals for serum creatinine concentrations in adults were 55-96 mumol/L (6.2-10.9 mg/L) in men and 40-66 mumol/L (4.5-7.5 mg/L) in women, and for urine, 9.46-19.01 mmol/day (1070-2150 mg/day) in men and 6.75-10.61 mmol/day (764-1200 mg/day) in women. The reference intervals of creatinine clearance were 88.0-176.4 mL/min in men and 75.7-173.0 mL/min in women.

Adult↗
PubMed1992

Low susceptibility of nude mice to induction of invasive urinary bladder cancers by N-ethyl-N-(4-hydroxybutyl)nitrosamine.

A time- and dose-dependent study of N-ethyl-N-(4-hydroxybutyl)nitrosamine (EHBN) bladder carcinogenesis was performed in nude mice maintained on tap water containing 0.025% EHBN for 4, 12, and 20 weeks ad libitum. A total of 13 invasive tumors, comprising 11 transitional cell carcinomas (TCCs) (84.6%) and 2 squamous cell carcinomas (SCCs) (15.4%), were found. Compared with previous results for B6C3F1 mice exposed to the same EHBN insult, the numbers of invasive carcinomas induced in nude mice, and especially of SCCs, were low. In order to ascertain whether this difference in cancer incidence between nude and B6C3F1 mice was due to variation in urinary excretion, the metabolism of EHBN was also investigated and compared with that of N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). Respective total urinary excretions over 48 hr of N-ethyl-N-(3-carboxypropyl)nitrosamine (ECPN) or N-butyl-N-(3-carboxypropyl)nitrosamine (BCPN), the ultimate carcinogenic species of EHBN or BBN, were 822.4 +/- 41.4 micrograms and 530.4 +/- 81.0 micrograms, respectively, in nude mice, and 800.6 +/- 83.7 micrograms and 407.8 +/- 69.7 micrograms, respectively, in B6C3F1 mice. In conclusion, although it is apparent that nude mice have a low susceptibility to EHBN induction of urinary bladder cancer, this does not appear to be dependent on reduced metabolism to the active form.

Animals↗
PubMed1992

Spatial and developmental changes in the respiratory activity of mitochondria in early Drosophila embryos.

Mitochondria of early Drosophila embryos were observed with a transmission electron microscope and a fluorescent microscope after vital staining with rhodamine 123, which accumulates only in active mitochondria. Rhodamine 123 accumulated particularly in the posterior pole region in early cleavage embryos, whereas the spatial distribution of mitochondria in an embryo was uniform throughout cleavage stages. In late cleavage stages, the dye showed very weak and uniform accumulation in all regions of periplasm. Polar plasm, sequestered in pole cells, restored the ability to accumulate the dye. Therefore, it is concluded that the respiratory activity of mitochondria is higher in the polar plasm than in the other regions of periplasm in early embryos, and this changes during development. The temporal changes in rhodamine 123-staining of polar plasm were not affected by u.v. irradiation at the posterior of early cleavage embryos at a sufficient dosage to prevent pole cell formation. This suggests that the inhibition of pole cell formation by u.v. irradiation is not due to the inactivation of the respiratory activities of mitochondria. In addition, we found that the anterior of Bicaudal-D mutant embryos at cleavage stage was stained with rhodamine 123 with the same intensity as the posterior of wild-type embryos. No pole cells form in the anterior of Bic-D embryos, where no restoration of mitochondrial activity occurs in the blastoderm stage. The posterior group mutations that we tested (staufen, oskar, tudor, nanos) and the terminal mutation (torso) did not alter staining pattern of the posterior with rhodamine 123.

Animals↗
PubMed1992

In vivo 31P nuclear magnetic resonance spectroscopy in patients with old myocardial infarction.

To assess the usefulness of in vivo 31P nuclear magnetic resonance (NMR) spectroscopy, we investigated spectra from the myocardium in 6 patients with old Q-wave infarction (QMI), 6 with old non-Q-wave infarction (NQMI) and 9 controls by ECG-gated depth-resolved surface-coil spectroscopy. External hexamethylphosphoric triamide (HMPT) was used to quantify the signal intensities. Left ventricular weight in the region of interest (LVW) was estimated from 1H magnetic resonance images. The extent score by 201Tl scintigraphy was determined in 3 QMI and 4 NQMI patients. No significant differences were found among the 3 groups in peak area ratios of 31P NMR spectra to phosphocreatine (PCr) or adenosine triphosphate (ATP). Compared with controls, significant reductions were observed in values for the peak areas of PCr normalized by the standard HMPT (PCr/HMPT) or by both HMPT and LVW (PCr/HMPT/LVW) for QMI patients (p less than 0.05), and in ATP/HMPT and ATP/HMPT/LVW for QMI and NQMI patients (p less than 0.01). There was a significant negative correlation between ATP/HMPT and the 201Tl scintigraphy extent score (p less than 0.05). These findings suggest that in vivo 31P NMR spectroscopy can detect high-energy phosphate reduction in the infarcted myocardium and may be useful in evaluating myocardial viability.

Adenosine Triphosphate↗
PubMed1992

Toxigenic type A Pasteurella multocida as a causative agent of nasal turbinate atrophy in swine.

Although no clinical signs of atrophic rhinitis (AR) were recognized in 2- and 5-week-old pigs, approximately 60% of 2- to 6-month-old pigs showed clinical signs of AR in an affected pig farm. None of the pigs had normal turbinate at slaughter. Bordetella bronchiseptica was not isolated from any of the pigs before onset and incipient stage of the outbreak (2-week to 2-month-old). Pasteurella multocida of capsular type D was not isolated from any of those pigs. However, toxigenic P. multocida of capsular type A was isolated from a number of the pigs immediately before onset and incipient stage of the outbreak. Thirty-six-day-old primary specific-pathogen-free pigs were inoculated intranasally with a toxigenic type A P. multocida isolated from a 5-week-old pig. Severe nasal turbinate atrophy was observed in those pigs which were necropsied at 3 weeks post-inoculation. This is the first report on outbreak of severe nasal turbinate atrophy induced by toxigenic type A P. multocida in Japan.

Animals↗
PubMed1992

Difference of rejection between heart and heart-lung transplantation in rats: flowcytometric analysis of graft infiltrating lymphocyte subsets.

Reported clinical and experimental observations indicate that heart grafts in combined heart-lung transplantation are less frequently rejected than heart grafts transplanted alone. In order to elucidate the mechanism of this difference, twenty-eight inbred male Lewis rats receiving heterotopic allografts from inbred male Fisher rats were evaluated for surface markers of graft infiltrating lymphocytes (GIL) and peripheral blood lymphocytes (PBL) using flowcytometry. Monoclonal antibodies investigated in this study were W3/25 (anti-helper T lymphocyte), OX8 (anti-suppressor/cytotoxic T lymphocyte), OX39 (anti-interleukin 2 receptor), and OX6 (anti-MHC class II antigen). In the acute study, a heart transplanted group (n = 7) and a heart-lung transplanted group (n = 7) without immunosuppression were studied. In the chronic study, cyclosporine (10 mg/kg/day i.m.) were administered in the heart transplanted group (n = 7) and the heart-lung transplanted group (n = 7). Both in the acute and chronic studies, the proportion of W3/25 positive cells in GIL of heart grafts of the heart transplanted group was significantly higher than that of heart grafts and lung grafts of the heart-lung transplanted group. OX8 positive cell proportion in GIL of heart grafts and lung grafts of the heart-lung transplanted group were significantly higher than that of heart grafts of the heart transplanted group. These results lead us to speculate that suppressor T lymphocytes are an important distinguishing factor in the rejection processes of heart allografts and heart-lung allografts as observed in clinical experience.

Animals↗
PubMed1992

Left ventricular performance at rest and during exercise in patients with dual-chamber pacemakers.

In 13 patients with an implanted dual-chamber atrioventricular (AV) demand pacemaker, left ventricular performance was elicited by pacing mode manipulation for study using gated cardiac pool scintigraphy at rest and during exercise. There was no significant difference between DDD and VVI at 70 and 90 beats/min with respect to cardiac output, peak ejection rate or peak filling rate. At 110 beats/min, the cardiac output was greater with DDD as compared to VVI. The peak filling rate was also significantly greater with DDD as compared to VVI (DDD: 3.6 vs VVI: 2.8 EDV/s, p less than 0.05). During exercise the cardiac output was greater with DDD as compared to VVI at the same rate. The peak filling rate during exercise was significantly greater with DDD as compared to VVI (DDD: 3.0 vs VVI: 2.5 EDV/s, p less than 0.01). We conclude that DDD is more beneficial than VVI in maintaining cardiac performance during exercise.

Adult↗
PubMed1992

[A case of Bufferin induced acute interstitial nephritis--analysis of immune cells and cytokine].

This paper describes a case report of acute interstitial nephritis associated with Bufferin. A 15-year-old girl were referred to our hospital due to fever and renal dysfunction. Laboratory findings showed elevation of serum BUN and creatinine, and increased urinary beta 2-MG excreation. Light microscopic findings of her renal biopsy specimen revealed edema and numerous inflammatory cells in the interstitium, and minor alterations in glomeruli. The interstitial infiltrates consisted mainly of T cells and also monocytes/macrophages. Interstitial cells were labelled with antibodies to interleukin (IL)-1 and tumor necrose factor (TNF). Bufferin was positive by lymphocyte stimulation test. Thus, we considered that this drug was causative in this case. This observation suggests the participation of cell-mediated immune injury in drug induced acute interstitial nephritis.

Acute Disease↗
PubMed1992

Effect of intra-aortic balloon pumping after cardiac surgery: comparative study of use in coronary bypass and valve replacement.

To compare the effects of intra-aortic balloon pumping (IABP) between use for coronary artery bypass grafting (CABG) and for valve replacement, the results were reviewed in 513 patients who underwent CABG (n = 215) or valve replacement (n = 298). The rate of weaning from IABP and in-hospital survival after IABP support were excellent in CABG patients, where all 21 CABG patients (100%) and 17 out of 25 valve replacement patients (68%) could be weaned from IABP, and 19 out of 21 CABG patients (90%) and 14 out of 25 valve replacement patients (56%) survived for a long period. From comparative studies of pre- and postoperative data, the duration of IABP support in patients who could be weaned from IABP or who achieved in-hospital survival tended to be more prolonged in patients with valve replacement than in those with CABG. Among patients having IABP postoperatively, 4 CABG patients and 8 valve replacement patients had definite indications for IABP support. In the other 34 patients, preoperatively depressed cardiac function was observed in 12 patients where most of them were patients with valve replacement. Postoperative improvements in cardiac index were not as marked in patients undergoing valve replacement with IABP. The outcome for patients who had definite causes of post-operative cardiac failure, which were more numerous in the valve replacement group, was poor even if they could be weaned from much longer IABP support. In conclusion, the IABP was more effective in patients with CABG compared with those with valve replacement, because the number of patients who had a depressed cardiac function during the pre- and postoperative periods was lower in the CABG group and the incidence of serious perioperative complications was less frequent in these patients.

Adult↗
PubMed1992

Effect of pamidronate in a rat hypercalcemia model induced by cholecalciferol.

Pamidronate (disodium 3-amino-1-hydroxypropylidene-1,1-bisphosphonate pentahydrate, CGP 23339A, CAS 57248-88-1) has been show to provide a potent antihypercalcemic effect through the inhibition of calcium release from the bone. The time course study on the antihypercalcemic effect of pamidronate was performed using a rat hypercalcemia model induced by orally administered cholecalciferol. The onset of the antihypercalcemic effect was observed within 48 h after a single i.v. injection of pamidronate at 1 mg/kg and this effect was sustained for 19 days. The time course of the antihypercalcemic effect of pamidronate in combination with calcitonin was also examined in the same model. The onset of the antihypercalcemic effect was observed within 4 h after combination therapy with a single i.v. injection of pamidronate at 1 mg/kg and successive i.m. injections of calcitonin at 3.2 IU/kg and the effect was of sufficient duration. These results suggest that pamidronate has a pronounced effect in controlling hypercalcemia and provides a long-lasting effect by a single i.v. administration. Moreover, the use of pamidronate in combination with calcitonin may be useful when a quicker onset of action is required clinically.

Animals↗
PubMed1992

[Echocardiographic assessment for surgical treatment in patients with aortic stenosis].

The diagnostic value of preoperative echocardiography was assessed in 51 patients with aortic stenosis. We measured 1) left ventricular-aortic pressure gradient (LV-Ao PG), 2) aortic valve area (AVA), 3) grade of LV hypertrophy and function, and 4) aortic annulus diameter for determining the availability and size of a prosthesis. The maximal instantaneous PG (max-PG) by continuous-wave (cw) Doppler echocardiography correlated well with the peak-to-peak PG by cardiac catheterization (cath), and their correlation equation was y = 1.49 x -48.3 with a correlation coefficient of 0.90. Excellent correlations were also found between cw-max PG and cath-max PG (r = 0.84), and between cw-mean systolic PG and cath-mean systolic PG (r = 0.80). The AVA of the echocardiogram, which was derived from the stroke volume using Gibson's M-mode echocardiographic formula and the cw-Doppler echocardiographic mean gradient, correlated well with the AVA of the cardiac catheterization using Gorlin's formula (y = 1.33 x -0.61, r = 0.79). Preoperative LV pump function, which was obtained from the M-mode echocardiogram, correlated inversely with end-systolic wall stress, and a depressed LV pump function was observed in patients with inadequate hypertrophy. In such patients, however, depressed function was alleviated after surgical treatment. Thus, we considered that cardiac catheterization for further examination is unnecessary, even in such patients. To determine the available size of the prosthesis, measurement of the inner diameter of the aortic annulus on the long-axis cross-sections was the most useful.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Development of a mandibular tracking device with six degrees of freedom using optoelectronic system.

The purpose of this study was to develop a prototype handy mandibular tracking device with six degrees of freedom using the optoelectronic kinematic data acquisition system and to evaluate its accuracy. The system consisted of the light-weight sensor part mounted on the mandibular incisor portion and two 2-D PSD cameras positioned in front of the patient. On the sensor part, three light emitting diodes (LEDs) were attached in triangular form. Displacements of the sensor part were detected by two cameras, transformed into electric signals, and sampled by A/D converter in a desktop computer. Since the overall accuracy of this system was about 0.03 mm in the displacement and 0.06 degrees in the rotation angles, this system was proven to be capable for the wide range of clinical application.

Humans↗
PubMed1992

[Clinical and hemodynamic sequelae of mitral prostheses evaluated by Doppler echocardiography].

To determine the relative superiority of a prosthesis in the mitral position, in vivo hemodynamics were examined by Doppler echocardiography, and the results were compared with other types of mechanical mitral valves including 63 Björk-Shiley convexo-concave (BS) values, 30 Duromedics (DM) valves, and 58 Medtronic Hall (MH) valves. For this comparison, the following indices were evaluated: peak velocity of mitral flow (PV), mitral valve orifice area (MVA), mitral valvular regurgitation, New York Heart Association (NYHA) classification, pulmonary capillary wedge pressure (PC), cardiac index (CI) and valve-related complications. On Doppler echocardiograms, PV ranged from 1.2 to 2.0 m/sec with a mean of 1.6 m/sec. There was no evident relationship between the PV and the valve size in each type of prosthesis, and no significant difference in the PVs among the valves. The mean MVA was 2.6 cm2 (25 mm DM, 25 mm MH), which was regarded satisfactory from a clinical standpoint. MVA increased with the increase in the valve size in all types of valves, and of all sizes, MVA was larger in the DM and MH groups than in the BS group. Similarly, the incidence of valvular regurgitation was relatively low in all groups, and the degree of regurgitation proved to be grade II or less in all cases. As for the clinical results, clinical symptoms (NYHA) and hemodynamic states (PC, CI) improved postoperatively, with the differences among the types of prosthetic valves being insignificant. The incidences of thromboembolism, valvular thrombosis, valve failure and prosthetic endocarditis were relatively low in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1992

[Methods and normal ranges for predicting diseases].

Predictions of diseases require suitable laboratory tests, mathematical methods for analyzing data and true normal ranges. Normal ranges are to be defined as 95% range of test results obtained on healthy subjects. "Healthy" subjects here refers to the persons who are free of the particular disease now and previously. However, to confirm the disease-free condition, laboratory test result must be evaluated on the basis of a normal range. This is a dilemma. The only way to overcome this problem is to follow a cohort for 10 or 20 years. Some of the "healthy" subjects will be suffering from diseases, while the others will still remain free of disease. That the latter persons would be the truly "healthy" subjects. Therefore, by their laboratory data and/or specimens such as serum every year we can determine the differences between the laboratory data of the patients and the true healthy subjects. In this respect, the development of laboratory database systems and serum banks are essential. We report a mathematical method for selecting significant data items for such a database and decision-making.

Algorithms↗
PubMed1992

Pharmacological profile of the new antidepressant levoprotiline.

The pharmacological properties of a new antidepressant, levoprotiline ((-)-R-a-[(methylamino)methyl]-9,10-ethanoanthracene-9(10H)- ethanol hydrochloride, CGP 12103 A, CAS 76496-69-0) were investigated. 1. Central nervous system: Levoprotiline did not have any marked effects on the general behaviour of mice and rats at low doses, however it slightly suppressed the righting reflex and spontaneous motor activity of mice at higher doses. In rats, chewing behaviour and salivation were observed at higher doses. Levoprotiline had no effects on the traction test (mice) and inclined screen test (rats). Levoprotiline induced a slight drowsy EEG pattern, the effect being similar to that of typical antidepressants such as maprotiline or imipramine but the degree of potency of levoprotiline was less than that of the latter two drugs. Levoprotiline and maprotiline did not inhibit the arousal response induced by physostigmine, while imipramine clearly suppressed the response. 2. Respiratory and cardiovascular system: Heart rate decrease and QT prolongation were observed in anesthetized dogs. In an in vitro study, levoprotiline caused only slight stimulation of noradrenaline transmission in the isolated guinea pig atrium. 3. Smooth muscle: The effects of levoprotiline on the contractile response to histamine, acetylcholine and serotonin in the isolated guinea pig ileum were compared with those of maprotiline or imipramine. While levoprotiline potently inhibited the contractile response to histamine, its inhibition of acetylcholine-induced contraction was the weakest of the three compounds studied. No remarkable effect was observed in serotonin induced contractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗