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Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 739 records · Page 41Linked to original sources
PubMed1995

[Clinical efficacy of sulbactam/cefoperazone for the treatment of geriatric patients with respiratory tract infections].

We performed clinical studies on sulbactam/cefoperazone (SBT/CPZ) for the treatment of geriatric patients with respiratory tract infections. Seven patients with pneumonia, 7 with acute bronchitis, 6 with chronic respiratory tract infections were treated with SBT/CPZ. The patients were administered with a daily dose of 2.0 g or 4.0 g for 4-14 days. The clinical responses were excellent in 3, good in 13, fair in 3, and poor in 1 patients. The efficacy rate was 80.0%. No side effects were observed in any patients, but elevations of GOT, GPT were observed in two cases. Causative organisms were E. coli (2 strains), P. aeruginosa (2), MSSA (1), MRSA (1), S. pneumoniae (1), H. influenzae (1), K. oxytoca (1), and E. aerogenes (1). The bacteriological effect rate was 60%. One strain of MRSA and one of two strains of P. aeruginosa persisted in 2 patients.

Aged↗
PubMed1995

Correction by oral adsorbent of abnormal digestive tract milieu in rats with chronic renal failure.

In order to examine the mechanism by which the oral carbonaceous adsorbent, AST-120 delays the appearance of glomerular sclerosis, experiments were carried out in 120 male Sprague-Dawley rats weighing 285-320 g. The rats were first subjected to 2/3, 3/4, and 4/5 nephrectomy (n = 40). The experiments were begun at 2 weeks after the surgery, and were performed over an 8-week period. Half of each group (n = 20) was administered 1 g/day of liquid AST-120, and the other half received liquid vehicle solution with pair feeding in each group. In the 2/3 nephrectomized group the administration of AST-120 delayed the occurrence of glomerular hypertrophy and prevented the appearance of glomerular sclerosis without any significant differences in renal function, systemic blood pressure (SBP), and urinary protein excretion (U-P). In the 3/4 nephrectomized group the administration of AST-120 delayed the appearance of glomerular hypertrophy and sclerosis with significant decreases in SBP and U-P. In the 4/5 nephrectomized group the administration of AST-120 delayed the appearance of glomerular sclerosis and prevented a decrease in renal function. It is concluded that administration of the oral adsorbent AST-120 delays the occurrence of glomerular sclerosis by delaying the appearance of glomerular hypertrophy, systemic hypertension, and the increase in proteinuria. It can be therefore mentioned that the accumulating substances in the digestive tract worsen the abnormal milieu of chronic renal failure.

Absorption↗
PubMed1995

Recombinant human erythropoietin has no direct or strong vasoconstrictor effects in vivo and in vitro.

An elevation of blood pressure is observed in approximately 30% of dialysis patients treated with recombinant human erythropoietin (rHuEPO). Various studies have been performed in order to elucidate possible underlying mechanisms, but it is not yet well understood whether there is one major mechanism involved. In this present study, samples were obtained from male normotensive Wistar-Kyoto rats (WKY) and genetically hypertensive rats (SHR) at the age of 5 and 20 weeks. Thoracic aorta rings, with or without endothelium, isolated from WKY and SHR were used to evaluate the direct effect of rHuEPO on vascular smooth muscle by measuring the tension of vascular smooth muscle induced by various concentrations (1-100 IU/ml) of rHuEPO. Also, rHuEPO (10, 100, 1000 and 10,000 IU/kg) was intravenously administrated and the changes in mean blood pressure were recorded for 5-10 min. rHuEPO produced no significant contraction in the rat aortae in any of the preparation studies, in the presence or the absence of endothelium. The intravenous administration of rHuEPO had no immediate effect on mean blood pressure in 5- and 20-week-old WKY and SHR. These results suggest that the elevation of blood pressure observed in the clinical setting following the administration of rHuEPO is not due to a direct pressor effect on vascular smooth muscle.

Animals↗
PubMed1995

[Surgical treatment and long-term results of cardiac myxoma in 38 patients].

Long-term results of thirty-eight patients with cardiac myxoma, who underwent resection at National Cardiovascular Center between May, 1978 and December, 1993, were reviewed focussing on embolism, cerebral complication, tumor recurrence and metastasis. The mean age was 49.6 years (range 0 to 74) in 20 female and 18 male. Overall follow-up were known for 35 of 38 patients (92.1%), and an average of follow-up period was 6.7 years (range 0.5 to 15.9 years). 15 of 38 patients (34.2%) had embolism (brain 10, peripheral artery 4, coronary 1) preoperatively. All patients survived operation and the hospital mortality rate was 0%. Long-term results were almost satisfactory (myxoma related-death in one patients). However, distant metastasis occurred in two patients, and tumor recurrence in one patient irrespective of a presence of preoperative embolism. Cerebral embolism occurred in one patient and cerebral arterial lesins were noticed in five patients postoperatively. Cardiac myxoma has a malignant potentiality and a close follow-up is necessary about recurrence, metastasis and cerebral artery disease.

Adolescent↗
PubMed1995

[Clinical evaluation of 99mTc-MAG3 as a radiotracer to assess the function of transplanted kidney: comparison with 123I-OIH].

99mTc-MAG3 (mercaptacetyl glycilglycilglycine) is a newly developed radiopharmaceutical for the functional imaging of kidneys. We evaluated the clinical usefulness of 99mTc-MAG3 in 12 cases (7 men and 5 women, aged from 18 to 57 years old) with transplanted kidney, and compared it with 123I-OIH (o-iodohippurate). Immediately after bolus injection of 300 MBq of 99mTc-MAG3, first pass images (1 frame/3 sec for 1 min) and dynamic renal images (1 frame/60 sec for 30 min) were recorded. In 10 of 12 cases, the same examination was carried out using 37 MBq of 123I-OIH within 2 weeks. Because of its larger dose and suitable gamma-ray energy, 99mTc-MAG3 provided much better images than 123I-OIH, particulary among first pass images. Effective renal plasma flow (ERPF) calculated from the clearance of 99mTc-MAG3 was less (about 70%) than that of 123I-OIH, however, a strong correlation (r = 0.98, p < 0.001) was observed between the ERPF values of the two radiotracers. No adverse effects were caused by 99mTc-MAG3. Our data suggested that 99mTc-MAG3 was a promising radiopharmaceutical with which to evaluate regional dynamic renal function.

Adolescent↗
PubMed1995

[Clinicopathological study of IgA nephropathy: the influence of age on renal histological changes and prognosis].

Clinicopathological features and prognosis were studied in 291 Japanese patients (4 to 60 years of age) with IgA nephropathy to investigate the influence of age on this disease. Histological assessment was done using the semiquantitative scoring system consisting of the activity index (A1) and chronicity index (C1). 1) Cl scores, especially global glomerulosclerosis and tubulointerstitial change, markedly increased with age, while Al scores slightly increased. 2) The Cl scores and rate of chronic renal failure (CRF) increased, especially in patients beyond 30 years of age. 3) A higher rate of CRF or regular hemodialysis was found in patients with Cl > or = 4 compared to those with Cl < 4 (21.7%, 2.9% respectively). These results suggest that chronic, irreversible histologic changes increase with age, especially beyond the age of 30 years, which worsens the prognosis of patients with IgA nephropathy.

Adolescent↗
PubMed1995

[Major symptoms of multiple myeloma and their management--neurologic disorders].

The incidence of neurologic complications in multiple myeloma has been reported as high as 10 to 40% of the patients and neurologic symptoms are sometimes recognized as first manifestation of the disease. Neurologic lesions in multiple myeloma are classified as follows. 1. cerebral disorders (due to intracranial lesion, or renal insufficiency, hypercalcemia, anemia without intracranial lesion), 2. cranial nerve and intracranial involvement, 3. spinal cord or cauda equina compression, 4. radiculopathy (involvement of a nerve root). 5. peripheral neuropathy, Incidence, symptoms, and management of each disorder are reviewed with presenting case reports of the patients with multiple myeloma cases who showed neurologic disorders in our institution.

Adult↗
PubMed1995

The ocular hypotensive effect of the ETB receptor selective agonist, sarafotoxin S6c, in rabbits.

PURPOSE: Endothelin-1 (ET-1) is known to affect intraocular pressure (IOP) in rabbits, and the IOP response is likely to be mediated by the receptors ETA, ETB, or both. Sarafotoxin S6c (STX-S6c) is a selective agonist to ETB receptors. The authors attempted to clarify the role of ETB receptors in changes in IOP induced by ET-1 in rabbits using STX-S6c and to determine the relationship between the IOP response and various doses of STX-S6c. METHODS: Each concentration (10(-4) to 10(-7) M) of STX-S6c was injected intravitreally (20 microliters/eye) into one eye. The contralateral eye of each was used as a control. The IOP was measured periodically using a calibrated pneumatonometer. Indomethacin (50 mg kg-1) or vehicle (10 ml kg-1; 0.05 M phosphate buffer) was administered intraperitoneally twice, before and after intravitreal injection of STX-S6c (10(-5) M), and IOP was measured in the same protocol for 24 hours. RESULTS: In the STX-S6c (10(-4) and 10(-5) M) group, the IOP reduction was significant compared with the baseline (P < 0.05 to P < 0.01), starting from 6 and 4 hours and continuing until 192 and 72 hours after injection, respectively. A solution of 10(-6) M STX-S6c also resulted in significant reduction of IOP observed from 24 to 72 hours after injection (P < 0.05). The 10(-7) M solution of STX-S6c failed to affect IOP. The area under the curve of IOP response exhibited a significant correlation with the doses of STX-S6c (r = -0.856; P = 0.0001) in the treated eyes. Treatment with indomethacin failed to affect the IOP reduction caused by STX-S6c (10(-5) M). Ciliary injection and some dilatation of the iridial vessels were observed in eyes that received higher doses of STX-S6c. CONCLUSION: STX-S6c reduces the IOP in rabbits in a dose-dependent fashion, presumably mediated through the ETB receptors.

Amino Acid Sequence↗
PubMed1995

Hyper-dopaminemia may produce an increased outlet resistance of the prostatic urethra: a case report of malignant pheochromocytoma.

We report on a 43-year-old man with difficult urination attributed to malignant pheochromocytoma with hyper-dopaminemia. A decrease and increase in the plasma dopamine values during the clinical course clearly coincided with improvement and deterioration, respectively, in urination difficulty. The prostatic peak pressure decreased by 37% when the plasma dopamine value was minimal. Detrusor function was normal throughout. Endocrinological and urodynamic studies suggested that hyper-dopaminemia produced an increased outlet resistance of the prostatic urethra without altering detrusor function. Thus, peripheral dopaminergic systems may influence voiding mechanisms, especially those involving the proximal urethra.

Adrenal Gland Neoplasms↗
PubMed1995

[The effect of an endothelin receptor antagonist, 97-139, on intraocular pressure in rabbits].

We studied intraocular pressure (IOP) response to an intravitreal injection of 10(-5)M (20 microliters) endothelin-1 (ET-1) in unanesthetized rabbits, and found a transient IOP rise followed by a prolonged IOP reduction. ET-1 (10(-6)M) caused a sustained IOP reduction without an initial IOP rise. The ETA receptor selective antagonist, 97-139 (10(-2)M, 20 microliters), had no effect when used alone; however, when used in combination with ET-1 (10(-5)M), 97-139 (10(-2)M) significantly blocked the ocular hypotensive response to ET-1. 97-139 (10(-3)M), when used with 10(-6)M ET-1, also suppressed the IOP reduction induced by ET-1. Aqueous prostaglandin (PG) E2, determined by radioimmunoassay, was significantly elevated following intravitreal injection of ET-1 (10(-5)M). Prior injection of 97-139 (10(-2)M) significantly suppressed the elevation of aqueous PGE2 concentration caused by ET-1 (10(-5)M). These results suggest that both the IOP response and the elevation of aqueous PGE2 following ET-1 injection are at least partially mediated by ETA receptor.

Animals↗
PubMed1995

[Recurrent bronchogenic cyst--a case report].

Mediastinal bronchogenic cyst is a benign tumor and occupied about 5% of mediastinal tumor in Japan. As a benign tumor, recurrence of bronchogenic cyst is very rare, and we found only 2 cases were reported. We experienced a recurrent bronchogenic cyst found 14 years after first operation. The patient was 56-year-old male, and admitted to our hospital for further evaluation of his abnormal shadow on chest roentogenogram. He had no symptoms. He was operated an bronchogenic cyst for 14 years ago. Chest X-ray, CT, and MRI demonstrated a paratracheal cystic mass which was suspected of a recurrent bronchogenic cyst. An operation was done, and the tumor was resected. A histopathological study showed that the tumor had thin wall and had a ciliated epithelium, then it was diagnosed bronchogenic cyst. The most likely explanation for the recurrence in our patient is an incomplete resection during the initial operation. It is though that only a very small amount of epithelial tissue need remain for recurrence. For prevention of recurrence, complete resection of cyst is necessary, and long-term follow-up is indicated to detect recurrence.

Bronchogenic Cyst↗
PubMed1995

[Morphological changes in major pelvic ganglion neurons and histological structure of bladder using rat model of partial urethral ligation].

Ninety six rats were divided into 4 groups (normal control group (N = 4), ligation group (N = 20), ligation-removed group (N = 36), and sham surgery group (N = 36)). The neuronal size of the 4-week ligated rats returned to normal 6 weeks after removal of the ligation. Rats ligated for 7, 11 and 20 weeks also exhibited a significant increase in the mean area but they could not make a complete recovery after removal of ligation for 6 weeks. Only the rats in the 1- and 4-week ligation groups could recover their neuronal size. Area densities of smooth muscle: connective tissue (ADsc ratio) was calculated using Elastica van Gieson staining sections of bladder strips. When ligation was removed, the ratio dropped and became nearly equal to the value of the sham surgery group. Only the 7-week group showed a lower ADsc ratio than the sham surgery group after the ligation was removed. These findings suggest that the reversibility of neuronal hypertrophy might become irreversible when the period of partial urethral ligation persisted beyond 7 weeks. Irreversible hypertrophy of major pelvic ganglion (MPG) neurons might be greatly related with the irreversibly enlarged fibrous bladder which could not show the same ADsc ratio as was seen in the sham surgery groups.

Animals↗
PubMed1995

[Experimental studies on evaluation of rat testicular function by 31P magnetic resonance spectroscopy].

To evaluate the efficacy of 31P magnetic resonance spectroscopy (31P MRS) as a diagnostic method for abnormal testicular function, we examined three conditions using rat testes, ischemia, irradiation, and hormone manipulation. 1) Ischemia: Immediately after clamping of the feeding vessels, ATP signals began to fall and disappeared within 60 minutes. With the release of blood supply after 3 hours of ischemia, ATP appeared within 2 hours. However, after more than 4 hours of ischemia, ATP did not recover within 2 hours and the testis became necrotic after 1 week. 2) Irradiation: 31P MRS of the testis 2 weeks after irradiation with 10 Gy., 9 MeV showed a significant decrease (P < 0.05) in the PME/beta-ATP ratio from 1.30 +/- 0.11 (control level) to 1.11 +/- 0.12 and a decrease in PME/PDE ratio from 1.43 +/- 0.17 to 1.13 +/- 0.20. However 3 weeks later, the PME/beta-ATP ratio recovered to a control level. 3) Hormone manipulation: In the testes 5 weeks after weekly intramuscular injections of estradiol benzoate and testosterone enanthate, PDE/beta-ATP ratio significantly increased (P < 0.01) from 0.83 +/- 0.09 (control level) to 1.03 +/- 0.19. 31P MRS is a non-invasive method for evaluation of various testicular abnormalities, and ATP signals may be useful to evaluate an acute ischemic change for example testicular torstion and the changes of PME, PDE signals may be useful parameters in the assessment of the status of spermatogenesis.

Adenosine Triphosphate↗
PubMed1995

[Morphological change and reversibility of major pelvic ganglion neurons using rat model of partial urethral ligation].

We made partial urethral ligation in female Wistar rats to evaluate the morphological change and the reversibility of the major pelvic ganglion (MPG) neurons before and after partial urethral ligation. Thirty rats were divided into 4 groups; normal control group (N = 3), ligation group (N = 9), release of ligation group (N = 9), and sham-operated group (N = 9). WGA-HRP (horseradish peroxidase with lectin wheat germ agglutinin) was injected into the right side of the bladder 4 days before the MPG neurons were removed. MPG was examined by the axonal tracer method. Rats with partial urethral ligation for 1 week exhibited a significant increase in the size (419.1 +/- 146.0 microns2) of the mean area of MPG neurons as compared to the normal controls (318.0 +/- 118.6 microns2), but they showed a steady decrease in size (304.2 +/- 118.6 microns2) similar to that in the sham-operated group (310.2 +/- 116.3 microns2) 3 weeks after the removal of the ligation. The rats with partial urethral ligation for 7 weeks and 11 weeks also exhibited a significant increase in the mean area (7w; 484.1 +/- 192.6 microns2, 11w; 549.4 +/- 181.3 microns2), but they did not show complete recovery (7w; 383.3 +/- 159.6 microns2, 11w; 549.6 +/- 279.5 microns2) as compared to the sham-operated group (7w; 324.4 +/- 124.9 microns2, 11w; 345.9 +/- 121.7 microns2) after removal of ligation. Only the 1-week ligation group showed recovery in neuronal size. These findings imply that the neuronal hypertrophy might become irreversible when the period of partial urethral ligation persisted beyond 7 weeks.

Animals↗
PubMed1995

[Effects of exogenous adenosine on myocardial recovery after acute hemorrhage].

This study was designed to investigate whether reperfusion with adenosine had an effect on myocardial high energy phosphate levels and cardiac function in hearts extracted from acutely hemorrhaged rats. Rats were bled to a mean arterial pressure of 0 mmHg for 5, 10 or 15 minutes and hearts were removed and assigned to one of three groups: 1) Hearts freeze clamped for measuring high energy phosphates; 2) Hearts perfused by Langendorff method at a constant perfusion pressure of 90 mmHg for 30 minutes followed by freeze clamping and determining high energy phosphates and; 3) Hearts perfused with adenosine (20 microM) and treated in the same way as in group 2. In group 1 myocardial ATP was significantly reduced as compared with control. When reperfusion started within 10 min, ATP contents recovered to the levels of control, and there were no significant changes between groups 2 and 3. LVP and LV dp/dt in group 3 were significantly higher than those in group 2. When reperfusion started after 15 min, ATP remained at a low level and few hearts could be resuscitated. These findings suggest that early resuscitation with adenosine might facilitate cardiac recovery following acute hemorrhage.

Adenosine↗
PubMed1995

[Clinical analysis of 62 patients with blunt renal trauma].

Sixty two patients with blunt renal trauma were treated and followed in our clinic between 1976 and 1993. Immediate operation was performed in one with major laceration, 3 with ruptures and one with pedicle injury, that is, nephrectomy in 4 and partial nephrectomy in one. Expectant management with the purpose of preserving the injured kidney was performed in 33 contusions, 20 minor lacerations and 5 major lacerations, resulting in no complications. We confirm that expectant management of blunt renal trauma may be reliable if the condition of the patient is stable even in the case of rupture, and the treatment of associated injury is preferential.

Accidents, Traffic↗