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Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 721 records · Page 40Linked to original sources
PubMed1995

Immunohistologic studies on subpopulations of lymphocytes in cattle with enzootic bovine leukosis.

The distribution of subpopulations of lymphocytes in lymph nodes and tumors from cattle with enzootic bovine leukosis (EBL) was examined by immunohistochemistry using a panel of monclonal antibodies against leukocyte differentiation molecules of EBL. The lesions in lymph nodes could be divided into three types based on the extent of infiltration and proliferation of neoplastic cells with provirus and differential expression of leukocyte differentiation molecules. The number of B-B2+, sIgM+ cells was reduced in frequency in follicles during the neoplastic cell proliferation. CD4- and CD8-positive alpha/beta T cells and gamma/delta T cells positive for WC1 (workshop cluster designation) were also reduced in frequency in areas infiltrated with neoplastic cells. Almost all neoplastic cells were B-B2- and IgM-positive. However, there were a few B-B2- and/or IgM-negative cells or cells stained faintly in all cases. WC1+ cells were not observed in tumor tissues. However, CD4+ and CD8+ cells were observed throughout tumor tissues, suggesting a role for these cells in tumor immunity.

Animals↗
PubMed1995

Phenotypic analysis of neoplastic cells from calf, thymic, and intermediate forms of bovine leukosis.

Immunohistochemistry and flow cytometric analysis were used with monoclonal antibodies to examine the phenotype of neoplastic cells from cattle with sporadic bovine leukosis (three cases of calf form, two cases of thymic form, and three cases of intermediate form). Three cases of calf form and two cases of intermediate form were positive for B cell lineage in immunohistologic examination and in flow cytometric analysis for B-B2+, sIgM+, and major histocompatibility class II+. Two cases of thymic form and one case of intermediate form were CD2+, CD5+, CD6+, and CD8+ in immunohistologic examination and in flow cytometric analysis. The results show that neoplastic cells develop from B and T cell lineages in sporadic bovine leukosis.

Animals↗
PubMed1995

Stress fractures of the medial malleolus: a case report.

The findings for stress fracture of the medial malleolus in two patients are presented. In case 1, a 54-year-old woman complained of gradual onset of pain over the medial malleolus after prolonged walking. Magnetic resonance imaging was useful in the early detection of the stress fracture of the medial malleolus. In case 2, a 16-year-old male developed stress fracture of the medial malleolus during repetitive Kendo fencing activity. Good clinical results were obtained with nonsurgical therapy.

Adolescent↗
PubMed1995

[Synthesis of estimated metabolites of 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinoline monohydrochloride monohydrate (NIK-247). I. Synthesis of mono-hydroxylated metabolites].

The two mono-hydroxylated metabolites of 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinoline monohydrochloride monohydrate (NIK-247), which is a new drug for the treatment of dementia, were synthesized to determine their chemical structures. Reduction of two tricyclic ketones, 9-amino-1,2,3,5,6,7-hexahydro-8H-cyclopenta[b]quinolin-8-one and 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]-quinolin-1-one, with NaBH4 afforded the corresponding racemic alcohols. The optically active mono-hydroxylated metabolites, (+)-9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-8-ol and (+)-9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-1-ol, were obtained by optical resolution of each racemic alcohol using (+)-di-p-toluoyl-D-tartaric acid.

Aminoquinolines↗
PubMed1995

Leukomyelopathy in ataxic calves.

Seventy-three fattening calves ranging from 6 to 15 months old on a farm were affected by ataxia over a period of four months. About 10 ataxic animals recovered after the administration of various kinds of vitamins and needle puncture therapy. The principal lesions in 14 ataxic animals examined were characterized by bilateral vacuolation with axonal degeneration confined to the spinal white matter. Ultrastructurally, the vacuoles were present in the periaxonal areas and bounded by dissociated myelin lamellae. No pathogen was isolated from the visceral organs of the animals. The serum copper remained within the normal range. Possible etiological factors remain unknown in the ataxic disease.

Animals↗
PubMed1995

Suppression of mitogenic response of bovine peripheral blood lymphocytes by ketone bodies.

Mitogenic response of peripheral blood lymphocytes from ketotic cows and effect of ketone bodies on lymphocyte blastogenesis were investigated. Glucose consumption index (GCI) values for phytohaemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) in the ketotic cows were significantly lower than those in the healthy dry cows. A significant negative correlation was observed between the GCI values and serum concentrations of total ketone and beta-hydroxybutyric acid. When lymphocytes from healthy dry cows were preincubated in the medium with acetoacetic acid or beta-hydroxybutyric acid, the GCI values for PHA and PWM were significantly lower than those in the lymphocytes without ketone bodies. These findings indicate that increased serum concentrations of acetoacetic acid and beta-hydroxybutyric acid in ketotic cows suppress lymphocyte blastogenesis.

3-Hydroxybutyric Acid↗
PubMed1995

Suppression of lymphocyte blastogenesis in cows with puerperal metritis and mastitis.

Mitogenic responses of peripheral blood lymphocytes in naturally occurring clinical puerperal metritis and mastitis were investigated. Glucose consumption index (GCI) values for phytohaemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) in the puerperal metritic cows and mastitic cows were significantly lower than those in the healthy cows. Suppression of lymphocyte blastogenesis was correlated to an increased concentration of serum ammonia in the puerperal metritic cows, and of alpha 1-acid glycoprotein (alpha 1AG) in the mastitic cows. Lymphocyte blastogenesis in the mastitic cows was also correlated to the serum concentration of vitamin E. These findings indicate that the puerperal metritic and mastitic cows are associated with impaired lymphocyte blastogenesis.

Ammonia↗
PubMed1995

Possible pre-Cushing's syndrome due to an adrenal adenoma incidentally discovered.

We demonstrated the functional evaluation of adrenal incidentaloma in 8 patients who had no abnormal finding associated with Cushing's syndrome. Adrenal tumors were incidentally discovered by abdominal echogram in 5 patients and by computed tomography (CT) in 3 patients. Serum cortisol levels and urinary excretion of 17-hydroxycorticosteroids (17-OHCS) were within normal limits in four of 8 patients. Urinary excretion of free cortisol was also within normal limits except for patient 8. Urinary excretion of 17-OHCS, however, was not suppressed by dexamethasone administration in five of 8 patients. Excretion of urinary 17-OHCS did not increase in response to metyrapone in 3 of 4 dexamethasone-insuppressible patients, but increased in 3 dexamethasone-suppressible ones. Serum cortisol increased in response to exogenous ACTH in all 6 patients examined. 131I-Adosterol accumulation was found in only the tumor side in 7 patients and bilaterally in one patient. Adrenalectomy was done in 7 patients, and microscopic findings showed adrenocortical adenoma. Serum cortisol was significantly suppressed in response to dexamethasone in the post-operative stage in all 7 patients examined. These results indicate that these adrenal incidentalomas seem to have a cortisol over-production which is dexamethasone-insuppressible and ACTH-dependent, and that they can be classified as "Pre-Cushing's Syndrome."

17-Hydroxycorticosteroids↗
PubMed1995

Glucose induces calcium-dependent and calcium-independent insulin secretion from the pancreatic beta cell line MIN6.

The present study was undertaken to determine whether there are Ca2+ -dependent and -independent pathways of glucose-induced insulin secretion from the pancreatic beta cell line MIN6. Glucose at a concentration of 16.7 mmol/l caused marked increases in cellular free calcium ([Ca2+]i) and insulin secretion, which depended on glucose metabolism. When cells were pretreated with 20 mmol/l mannoheptulose, an inhibitor of glucokinase, the 16.7 mmol/l glucose induced a rise in [Ca2+]i and insulin secretion disappeared. Also, L-leucine and L-arginine increased [Ca2+]i and induced insulin secretion. Under Ca2+ -free conditions, insulin release was still induced, without any change in [Ca2+]i, by these three different stimulants. The cumulative values of insulin secretion were 13.7-29.3% of the control, which were significantly less than that in the presence of Ca2+. Cellular alkalinization occurred in response to all these stimulants, irrespective of the presence of Ca2+. Forskolin, a diterpene activator of adenylate cyclase, produced insulin secretion independently of [Ca2+]i, which accompanied cellular alkalinization. Also, a high glucose level increased cellular cyclic AMP (cAMP) production in the presence and absence of Ca2+, and the effect was diminished by approximately 73% in Ca2+ -free conditions. These results indicate that a high glucose level stimulates both Ca2+ -dependent and -independent insulin secretion from pancreatic beta cells. We suggest that the cAMP production and the cellular alkalinization participate in the Ca2+ -independent mechanism. Spermatogonial proliferation is under the control of FSH, whereas the survival of germ cells is dependent on Sertoli cell function. The observed rise in the number of mitotically inactive Ad-spermatogonia can be explained by a transformation of Ap-spermatogonia into resting Ad-spermatogonia.

Alkalies↗
PubMed1995

Effect of prone position on apnea severity in obstructive sleep apnea.

We describe a patient with obstructive sleep apnea (OSA) whose apnea-hypopnea index (AHI) improved remarkably in the prone position accompanied by an improved sleep quality, despite a higher AHI in the supine position and even in the lateral position. Magnetic resonance imaging revealed the most dilated upper airway in the prone position, which suggests the role of anatomical narrowing of the upper airway as an important component in the pathophysiology of positional apnea patients. Further studies are needed to determine the therapeutic efficacy of a prone sleeping position in patients with OSA.

Humans↗
PubMed1995

[A young woman with rheumatoid arthritis who rapidly developed secondary amyloidosis].

A 22-year-old woman, who had been diagnosed as having rheumatoid arthritis (RA) 2 years before, was admitted to our hospital complaining of watery diarrhea (several times/day). She had been treated with low dose prednisolone (PSL) and auranofin in out-patient clinic. On admission, laboratory data showed moderate proteinuria (0.3 g/day) and positive CRP (2.7 mg/dl). Although the activity of RA was controlled by the administration of low dose methotrexate (7.5 mg/week) in addition to PSL, watery diarrhea and proteinuria did not improve. The biopsy of the stomach, rectum and kidney revealed the deposition of AA type amyloid protein, resulting in the diagnosis of secondary amyloidosis. Secondary amyloidosis has been reported as one of the common complications in RA patients, especially in old patients with a long history of RA. To our knowledge, however, there have been few reported cases who developed secondary amyloidosis so early during the course of RA as our case. We should be careful for the development of secondary amyloidosis even in young RA patients with short history of RA, when the disease is active.

Adult↗
PubMed1995

Intraocular pressure response to intravitreal injection of endothelin-1 and the mediatory role of ETA receptor, ETB receptor, and cyclooxygenase products in rabbits.

Endothelin-1 (ET-1) affects intraocular pressure (IOP) in rabbits. First, we studied IOP responses to the intravitreal injection of various doses of ET-1 ranging from 5 ng to 5 micrograms in unanesthetized rabbits, and observed a transient rise in IOP, from 0.5 to 2 h in duration, invariably followed by a prolonged IOP reduction, lasting for more than 72 h in rabbits treated with 0.5 microgram and 5 micrograms of ET-1. ET-1 (0.05 microgram and 0.15 microgram) resulted in a prolonged IOP reduction without an early IOP rise. Both IOP rise and reduction were significantly related to the dose of ET-1. A masked, randomized, study revealed that the intraperitoneal administration of indomethacin (50 mg/kg) prior to ET-1 injection significantly reduced the ocular hypertensive response, but not th ocular hypotensive response, to ET-1. The ETA receptor selective antagonist, 97-139 (155 micrograms) had no effect on IOP when used alone. However, when used in combination with 0.5 microgram of ET-1, 97-139 significantly inhibited both the IOP rise (0.5-2 h) and reduction (8-96 h) caused by ET-1. The ETB receptor selective agonist, sarafotoxin S6c (0.5 microgram), caused a sustained IOP reduction of 2 to 96 h in duration without the initial IOP rise. We also determined the concentration of prostaglandin (PG) E2 in the aqueous humor using radioimmunoassay techniques on samples obtained at 1 and 24 h after ET-1 injection, and examined the effects of pretreatment with indomethacin or 97-139 on PGE2 concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[An epidemiological study of stroke in a geriatric community--with special reference meteorological factors].

The incidence of cerebrovascular event during a period of 3 years in the geriatric society in Japan was examined along with the alternating pattern of cerebrovascular accidents in relation to aging and seasonal factors. The population of Tsuwano town was approximately 7000. The percentage of aged people over 65-year-old reached 23.1% in the 1990 national census. All cerebrovascular accident patients in our hospital and two outpatients clinic in this city were registered during the period from April, 1990 to March, 1993. The number of patients in the period was 95 cases, of which 19 were classified as transient ischemic attack (TIA), 30 as cerebral thrombosis, 16 as cerebral embolism, 10 as cerebral hemorrhage, 7 as subarachnoid hemorrhage, and 13 as unclassified cerebral infarction. The frequency of each type except TIA was 39.5% cerebral thrombosis, 21.1% cerebral embolism, 13.2% cerebral hemorrhage, and 9.2% subarachnoid hemorrhage. In all cases, hypertension was observed in 62.1%, and past history of cerebrovascular accident was observed in 29.5%. The cerebral embolism group was older than the other groups and one-half of this group had atrial fibrillation. Peak incidence differed by type of illness, TIA and cerebral embolism occurred uniformly throughout the year, but subarachnoid hemorrhage and cerebral thrombosis in the spring. The relationship of cerebrovascular accident to crisis, especially potentiation by cerebral thrombosis was evaluated in light of climatic factors.

Aged↗
PubMed1995

[Characterization of prostate cancer, benign prostatic hyperplasia and normal prostates using endorectal 1H magnetic resonance spectroscopy].

BACKGROUND: We evaluate the usefulness of 1H endorectal resonance spectroscopy to characterize prostate pathology. METHODS: With an endorectal surface coil we have studied 20 individuals with normal (1), benign hyperplastic (9) and malignant (10) prostates. RESULTS: The major findings of our studies were that the patients with cancer have a significantly lower citrate-to-choline ratio (cit/cho) and creatin-to-choline ratio (cre/cho) than the patients with BPH (p < 0.05). There is well correlation between cit/cho and gland-to-stroma ratio of the BPH tissue as well as histological grade of the cancer tissue. 1H spectroscopy offers the advantages of differential diagnosis between benign and malignant prostates. We, however, failed to demonstrate cancer in 2 cases; the lesion was too small in one case, and out of the region of interest in the other. It is necessary that the foci in the prostate is at least 1.5 X 1.5 X 1.5 cm3 of the volume in order to obtain genuine spectrogram of carcinoma. CONCLUSION: Endorectal 1H magnetic resonance spectroscopy can characterize metabolic differences between the normal and malignant prostate.

Adult↗
PubMed1995

Suppression of corneal graft rejection by subconjunctival injection of FK-506 in a rat model of penetrating keratoplasty.

The usefulness of the subconjunctival injection of FK-506 for suppression of allograft rejection was investigated in a rat model of orthotopic penetrating keratoplasty. Fischer rats were used as donors and Dark Agouti rats, as recipients. FK-506 was administered subconjunctivally in a dosage of 0.3 mg/kg/day for 15 consecutive days after penetrating keratoplasty was performed. Allograft rejection occurred within 8 to 10 days after keratoplasty in all untreated rats (n = 6). None of the FK-506-treated rats (n = 6) exhibited graft rejection during the 3-week observation period. Histologic examination showed marked infiltration of mononuclear cells in the stroma of corneal grafts from untreated rats 3 weeks after grafting. Inflammatory cells were only occasionally observed in grafts from FK-506-treated rats. Donor-specific cytotoxic T lymphocyte activity was completely suppressed in FK-506-treated rats 3 weeks after grafting. Our results indicated that subconjunctival injection of FK-506 effectively prevented corneal allograft rejection in a rat model of penetrating keratoplasty.

Animals↗
PubMed1995

[Value of serum PSA and PAP measurement with newly developed latex turbidimetric immunoassay].

Serum prostate specific antigen (PSA) and prostatic acid-phosphatase (PAP) levels in normal controls, and patients with prostate cancer, benign prostate hypertrophy (BPH) and other urological diseases were examined with a newly developed latex turbidimetric immunoassay (LPIA ACE PSA, LPIA ACE PAP, IATRON LABORATORIES, INC., Tokyo, Japan). The advantageous characteristics of this method are small amount (10 microliters) of serum required and short time (about 20 min.) for performing this assay. There was a high linear correlation between LPIA ACE PSA and MARKIT-F PA (r2 = 0.953), between LPIA ACE PSA and TANDEM-E PSA (r2 = 0.881) and between LPIA ACE PAP and ABBOTT-PAP EIA (r2 = 0.946). When the BPH patients (n = 110) were used as negative controls, the cut-off value of PSA was determined to be 4.3 ng/ml. Using this level as the cut-off value, the sensitivity was 78% (42 positive/54 untreated prostate cancer patients), specificity (negative rate in BPH patients) was 95% and efficiency was 89%. In a follow-up study of prostate cancer, the PSA value was elevated above the cut-off value in 68% at the time of clinical progression. These findings suggest that LPIA ACE PSA is a useful tool for serum PSA measurement. The cut-off value of PAP measured with LPIA ACE PAP was 9.0 ng/ml, which was determined by the same method as PSA. The sensitivity, specificity and efficiency ware 39%, 96% and 77%, respectively. These findings indicate that PAP is less useful than PSA in the diagnosis of prostate cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗
PubMed1995

Streptokinase gene variable region classification in streptococci: lack of correlation with post-streptococcal glomerulonephritis.

To investigate a possible causal role of streptokinase (SKase) in acute post-streptococcal glomerulonephritis (APSGN), the major variable region of SKase genes of Streptococcus pyogenes strains isolated from patients with and without APSGN were analyzed using the polymerase chain reaction, restriction enzyme analysis and the direct sequencing of SKase genes. In the APSGN-associated strains, six of nine revealed mutant classes corresponding to the nephritogenic classes I and II proposed by Johnston et al. [1992], the remaining three belonged to non-nephritogenic classes. In twenty strains not associated with APSGN, seventeen belonged to classes I and II, while three were from other classes. The major variable region of the SKase gene shows no apparent relation with induction of APSGN in humans, suggesting that unique classes of streptococcal SKase do not play a role in the pathogenesis of APSGN.

Adolescent↗