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Biomedical subjects

T Okimura

Publications and source records attributed to T Okimura.

At least 19 recordsLinked to original sources
PubMed1992

[Phosphorus 31-magnetic resonance spectroscopic studies of animal liver after extracorporeal shock wave lithotripsy].

The technique of magnetic resonance spectroscopy has been developed, and the study of high-energy phosphate metabolites in the liver using phosphorus 31 magnetic resonance spectroscopy (31P-MRS) has been reported in humans and animals, but few studies have used 31P-MRS for the evaluation of extracorporeal shock wave lithotripsy (ESWL) of the liver. In this study, 31P-MRS was used to evaluate the metabolic changes in hamster liver after ESWL and histological correlation was performed. Syrian golden hamsters were anesthetized and shock waves were irradiated to the left side of the liver. Hamsters were irradiated by LITHOSTAR-PLUS (SIEMENS) at a voltage of 19 KV. 31P-MRS was studied by JNM-GSX model 270 (6.34 Tesla). Typical peaks of 31P-spectra of hamster liver showed a tendency for PDE/beta-ATP, alpha-ATP/beta-ATP and gamma-ATP/beta-ATP to decrease among the irradiated group compared with the control group. However, there were no significant differences in PME/Pi, beta-ATP/Pi or (alpha-ATP-beta-ATP)/beta-ATP between the control group and irradiated group. With regard to intracellular pH and PDE/beta-ATP, a decreasing tendency was noted in the irradiated groups (p less than 0.05). There was no difference in the signal intensity of T1WI and T2WI on 1H-MRI, between these two groups. Pathologically, the irradiated group showed minor hemorrhage and edema in the liver, and subcapsular hematoma. The results obtained from 31P-MRS clearly showed the metabolic changes and were correlated well with the histological findings, but MRI was not capable of providing close visualization of post-ESWL liver damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Relationship between Ga-67 uptake and radiotherapeutic response of primary lung cancer (squamous cell carcinoma)].

This investigation was undertaken to evaluate the relationship between Ga-67 uptake and radiotherapeutic response to primary lung cancer (squamous cell carcinoma), Ga-67 uptake of tumor was estimated on 16 patients with untreated primary lung cancer (squamous cell carcinoma). Ga-67 uptake was then compared with the response to radiation therapy (tumor reduction ratio). There was statistically significant inverse correlation between Ga-67 uptake and response to radiation therapy (r = -0.701, p less than 0.01). The fewer the Ga-67 accumulation in the tumor, the more effective radiotherapy in reducing tumor size. In conclusion, Ga-67 scintigraphy appears to be able to predict the response of primary lung cancer (squamous cell carcinoma) to radiation therapy.

Carcinoma, Squamous Cell↗
PubMed1991

Orbital fractures: surface coil MR imaging.

Twenty-six patients with orbital fractures diagnosed with plain radiography and computed tomography were examined with surface coil magnetic resonance (MR) imaging. Fifteen patients had blow-out fractures, and 11 had maxillofacial complex fractures. In all patients with blow-out fractures, the location of the fracture was precisely indicated by the presence of prolapsed orbital fat. Incarceration of the extraocular muscle or orbital fat was correctly diagnosed with MR imaging, which was less sensitive in depicting maxillofacial fractures but was useful in assessment of soft-tissue involvement. Postoperative follow-up MR studies provided valuable information about the cause of motility impairment. While T1-weighted images are useful for the detection of the fracture site, both T1- and T2-weighted images are usually necessary for evaluating soft-tissue lesions. The results of this study indicate that surface coil MR imaging is an important adjunct procedure in the diagnosis and treatment of orbital fractures.

Adolescent↗
PubMed1990

Intraocular lesions in patients with systemic disease: findings on MR imaging.

Twenty-one intraocular lesions associated with various systemic diseases in 15 patients were studied by MR imaging. The disorders included diabetes mellitus, cardiovascular disease, Behçet disease, sarcoidosis, and ankylosing spondylitis. MR was performed on a 0.5-T system using a surface-coil technique. Ophthalmoscopic visualization of the fundus was precluded by the presence of opaque media in all cases. MR was found to be effective in demonstrating intraocular bleeding, vitreous opacity, detached lesions of the posterior pole, and eyeball deformity. Surface-coil MR is a useful adjunct in the evaluation of the eyes affected by systemic diseases, especially in patients with opaque media.

Adult↗
PubMed1989

[The influence of ferric metabolism on Ga-67 distribution in the human body].

This investigation was undertaken to make clear the influence of ferric metabolism on Ga-67 distribution in human body. Count ratios for each organ to femoral soft tissue (i.e. relative Ga-67 uptake) were calculated in 125 scintigrams obtained 48 hours following injection, and the relation between the relative Ga-67 uptake in each organ and serum Fe, or UIBC were investigated. The relative Ga-67 uptake in the liver and the lumbar vertebra had negative correlation to serum Fe, and had positive correlation to UIBC. However, there was no significant difference in the relative Ga-67 uptake in the lumbar vertebra between normal and high serum Fe group. Only in group with exceedingly low serum Fe, each vertebral body was visualized separately in posterior view of the abdomen. These findings indicated that in group with exceedingly low serum Fe, Ga-67 accumulated mainly in the bone marrow, and in group with high serum Fe, Ga-67 accumulated mainly in the bone. The urinary bladder was visualized only in group with high serum Fe, which suggested that the excretion of Ga-67 to the urine was continued yet at 48 hours after injection. Ferric metabolism affected remarkably on the relative Ga-67 uptake in the liver, the bone marrow and the bone, and also the excretion of Ga-67 to the urine.

Adolescent↗
PubMed1987

[Immunopharmacological actions of lumin (I): Anti-allergic actions of lumin].

We used lumin (4,4'-(3[2(1-ethyl-4-(1-H)quinolidene) ethylidene]) propenylene [bis(1-ethyl quinolinium iodide)]) as a photosensitive cyanin dye and studied its effects on various allergic reactions. We obtained the following results: Lumin slightly inhibited the production of IgE antibody, but showed no effect on the production of IgM and IgG antibodies. Lumin slightly inhibited homologous rat PCA at 48 hr. It also showed some inhibitory activity against histamine (His) release caused by in vitro antigen-antibody reaction. Lumin significantly inhibited the acceleration of the delayed-type hypersensitivity (DTH) reaction by cyclophosphamide (CY). The above results suggest that lumin shows anti-allergic activity through the mediation of immunopharmacological activity.

Animals↗
PubMed1987

[Immunopharmacological actions of lumin (II): Effect of lumin administration in NZB X NZW (B/W) F1 mice].

Lumin was administered at doses of 0.1 to 100 micrograms/kg for 5 months to NZB/W F1 mice as the model animal for studying systemic lupus erythematosus (SLE), a human autoimmune disease. The increase in anti-thymic autoantibody level was significantly inhibited at doses of 1 to 100 micrograms/kg. Also, the induction of suppressor T cells by concanavalin A was significantly promoted. In addition, recovery activity was significantly observed, over-coming the reduction in plaque-forming cell (PFC) response of anti-sheep erythrocytes at a dose of 100 micrograms/kg, as well as the reduction in PFC response of anti-trinitrophenylated-lipopolysaccharide at doses of 0.1 to 100 micrograms/kg. The above results prove that lumin exhibits an immunomodulating effect against immune disease in mice.

Animals↗
PubMed1986

Effect of neurotropin (NSP) on the in vivo and in vitro antibody responses in mice.

Intraperitoneal administration of neurotropin (NSP) did not modify the antibody response to sheep red blood cells (SRBC) in normal BALB/c mice. However, the suppressed antibody responses to SRBC in restraint-stressed mice were favorably restored to normal level by NSP at a dose of 10 or 25 mg/kg either before or even after the stress loading. The suppressed antibody responses in hydrocortisone-treated mice were restored by NSP when it was administered after cortisone. Moreover, NSP augmented the in vitro antibody response to a T cell-dependent antigen, SRBC, but not to T cell-independent antigens such as dinitrophenylated-Ficoll and trinitrophenylated-lipopolysaccharide.

Adjuvants, Immunologic↗
PubMed1986

Stress and immune responses. I. Suppression of T cell function in restraint-stressed mice.

Effects of restraint stress on humoral immune responses were investigated in mice. Mice were restrained for 12 hours per day at nighttime and released at daytime for 2 consecutive days, either before or after sheep red blood cell (SRBC) immunization. The antibody response to SRBC was markedly suppressed in mice that were restrained before antigen injection. In contrast, the response was not significantly affected when the stress was loaded after immunization. Oral administration of 10 mg/kg diazepam prevented the stress-induced suppression of anti-SRBC antibody response. On the other hand, antibody responses to T cell-independent antigens such as trinitrophenylated (TNP)-Ficoll and TNP-lipopolysaccharide were not suppressed. These results suggest that the restraint stress causes dysfunction of T cell populations in mice.

Animals↗
PubMed1986

Stress and immune responses. II. Identification of stress-sensitive cells in murine spleen cells.

The influences of restraint stress on the functions of T cells, B cells and adherent cells in antibody responses were investigated. Antibody response against sheep red blood cells (SRBC), a T cell-dependent antigen, in cultured splenocytes from restrained mice was reduced to about 40-50% of that from the control mice. Addition of normal T cells to these cultures, however, restored the suppressed response. Moreover, helper T cell activities were lowered in restrained mice. On the other hand, suppressor T cell activities induced by both concanavalin A (Con A) and SRBC were significantly decreased in restrained mice. However, the antibody responses to T cell-independent antigens in stressed mice were approximately 40% higher than the control response. These enhancement were also observed in T cell-depleted splenocytes. Polyclonal antibody response induced by lipopolysaccharide (LPS) was increased in stressed mice. Antigen presenting cell activities were little influenced by restraint stress. Proliferative response to Con A, but not that to LPS, was suppressed in splenocytes from restrained mice. These results suggest that both helper and suppressor activities of T cells are suppressed, but B cell activity is rather enhanced in splenocytes from restrained mice.

Animals↗
PubMed1986

Stress and immune responses. III. Effect of restraint stress on delayed type hypersensitivity (DTH) response, natural killer (NK) activity and phagocytosis in mice.

Several experiments were conducted to evaluate the influences of restraint stress on cell-mediated immune events in mice. Delayed type hypersensitivity response to sheep red blood cells was inhibited by the stress, regardless of the timing of restraint stress loading. The activity of phagocytosis of macrophages in vitro and in vivo were measured by using the zymosan-particle uptake method and the carbon clearance test, respectively. Both activities were decreased in restraint-stressed mice. The suppressed carbon clearance rate in stressed mice, however, was recovered by the transfusion of serum from normal mice. Natural killer activity in spleen cells was decreased to 30-50% of the control in stressed mice. However, no suppressor cells which could inhibit NK activity existed in the spleen from stressed mice. These results show that the restraint stress suppresses various kinds of cell-mediated immune events, which might play an important role in anti-tumor immunity.

Animals↗
PubMed1986

Stress and immune responses. IV. Adrenal involvement in the alteration of antibody responses in restraint-stressed mice.

We investigated the correlation between restraint stress-induced alteration of antibody responses and adrenal hormones. Adrenalectomy (Adx) blocked both the suppression of antibody response against T cell-dependent (TD) antigen and the enhancement of that against T cell-independent (TI) antigen in stressed mice. Adx also inhibited the atrophy of both thymus and spleen caused by restraint. Pre-treatment of metyrapone, an inhibitor of adrenocortical steroid biosynthesis, had an effect that was similar to, but far weaker than that of Adx on stressed mice. The pre-administration of phenoxybenzamine, an alpha-adrenergic blocking agent, to mice prevented both the inhibition of antibody response to TD antigen and the decrease in spleen cell number of restrained mice. A similar effect was observed in mice pre-treated with 6-hydroxydopamine, an adrenergic neuron degenerating agent. However, no effects of these two agents were observed on the enhancement of antibody response to TI antigen. The suppressive effect of the antibody response to TD antigen was augmented by the pre-administration of propranolol, a beta-adrenergic blocking agent. These results suggest that the suppression of the function of T cells in restrained mice are attributed to the released adrenocortical and adrenal medullary hormones and activated sympathetic nervous system and that the enhancement of B cell function is due to the adrenocortical hormones.

Adrenal Glands↗
PubMed1986

Effect of benzodiazepine derivatives: I. Augmentation of T cell-dependent antibody response by diazepam in mouse spleen cells.

Oral administration of diazepam at doses of 5-10 mg/kg to restraint-stressed mice resulted in almost complete recovery in the stress-induced suppression of the antibody response to sheep red blood cell (SRBC). Moreover, this compound restored the suppression of antibody response to SRBC in cyclophosphamide-treated mice. Diazepam treatment also enhanced the antibody response against SRBC in normal mice only when the animals were immunized with the reduced amount of antigen. It was demonstrated that antigen specific helper T cell activity was promoted by diazepam administration in mice. Addition of diazepam augmented the in vitro anti-SRBC hemolytic plaque-forming cell (PFC) response in mouse splenocytes without altering kinetics of the response. However, the enhancing effect was observed only when the drug was added to the medium at the culture initiation. On the other hand, antibody response to T cell-independent antigens such as trinitrophenylated (TNP)-Ficoll and TNP-lipopolysaccharide were not enhanced by diazepam. Concanavalin A or LPS-induced 3H-thymidine uptake into splenocytes were not stimulated by diazepam. These results suggest that diazepam promotes the antibody response through stimulating helper T cell functions.

Animals↗
PubMed1985

[Clinical usefulness of integrated images of the radionuclide liver angiogram to evaluate diffuse hepatic disease].

New imaging method that was integrated image of radionuclide liver angiogram was proposed. Patients were placed supine beneath gamma camera, so that the liver, spleen, heart, and lung were included in an anterior image. Integrated image was recorded for 100 s, following injection of 111-222 MBq (3-6 mCi) of 99mTc tin-colloid. 595 cases were examined, and classified into 3 groups as follows. Group I: Cases without hepatic dysfunction Group II: Cases with hepatic dysfunction Group III: Liver cirrhosis. Numbers of each group were 208 (35%), 305 (51%), and 82 (14%) respectively. Integrated images were qualitatively determined by macroscopic inspection. Comparing liver intensity and lung intensity, 3 patterns of integrated image were classified. Pattern I: Liver intensity was greater than lung intensity Pattern II: Liver intensity was equal to lung intensity Pattern III: Liver intensity was less than lung intensity Numbers of each pattern were 412 (69%), 125 (21%), and 58 (10%) respectively. Numbers of group III distributed into each pattern were 8 (10%) in pattern I, 29 (35%) in pattern II, and 45 (55%) in pattern III. The correct diagnosis of liver cirrhosis as follows. In a case of choosing pattern III as diagnostic criterion, sensitivity was 55%, and specificity was 97%. The positive predictive value was 78%, and the negative predictive value was 93%. Total accuracy was 92%. This new method seems useful in evaluating diffuse hepatic disease.

Heart↗