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Biomedical subjects

K Iwata

Publications and source records attributed to K Iwata.

At least 289 records · Page 16Linked to original sources
PubMed1991

A projection of the lens accommodation-related area to the pupillo-constrictor area in the posteromedial lateral suprasylvian area in cats.

The fiber connection between areas related to lens accommodation and to pupillary constriction was studied in the posteromedial lateral suprasylvian area (PMLS) in the extrastriate cortex of the cat. The accommodation-related area was located in the PMLS by microstimulation, and the anterograde tracer Phaseolus vulgaris leucoagglutinin was injected into this area. Anterogradely-labeled fibers and terminals were found in the upper part of the medial bank of the middle suprasylvian sulcus, the area corresponding to the pupillo-constrictor area in the PMLS. The labeling was also found in the fundus of the middle suprasylvian sulcus, the medial bank of the lateral sulcus and the superficial layers of the superior colliculus. It is concluded that the area related to lens accommodation projects to the area related to pupillary constriction in the PMLS.

Accommodation, Ocular↗
PubMed1991

[A case of intracerebellar hemorrhage in infancy].

Nontraumatic intracerebellar hemorrhage is rare during childhood. We report such a case due to rupture of arteriovenous malformation, in which surgery was able to bring about satisfactory recovery from deep coma without spontaneous respiration. This case shows that operative treatment should not be abandoned even though neurological deficits are very serious. This 6-year-old boy suddenly complained of headache while playing in a nursery and became restless. Because of deterioration of consciousness level followed by loss of respiration, he was transferred from a local physician to our clinic 4 hours after the onset. Computerized tomography scan disclosed a hematoma in the cerebellar hemisphere. Emergency suboccipital craniectomy was carried out 1 hour later. Immediately after operation, respiration was restored. Vertebral arteriography was performed 1 month after the operation, when the patient had recovered but could barely communicate with his family. The study revealed a small arteriovenous malformation supplied by the anterior inferior cerebellar artery. The malformation was removed 3 months after admission. The postoperative course was uneventful and the patient attended a primary school without neurological deficits except for slight ataxia 6 months after the onset.

Cerebellar Diseases↗
PubMed1991

[Optic disc measurements with computerized image analysis in normals, ocular hypertensives and glaucomas].

Optic disc measurements were performed with computerized image analysis (Rodenstock Optic Nerve Head Analyzer) in one eye of each patient of 74 normal controls, 41 ocular hypertensives and 41 patients with early stage glaucoma. In normal controls, the rim area was 1.62 +/- 0.48 mm2 (mean +/- s.d.), cup area 0.80 +/- 0.41mm2, cup volume 0.34 +/- 0.16mm3, cup/disc ratio 0.43 +/- 0.19. For Ocular hypertensives, rim area was 1.32 +/- 0.44mm2, cup area 1.32 +/- 0.78mm2, cup volume 0.56 +/- 0.41mm2, cup/disc ratio 0.51 +/- 0.41. For glaucomas, the rim area was 1.07 +/- 0.47mm2, cup area 1.3 +/- 0.78mm2, cup volume 0.75 +/- 0.40mm3, cup/disc ratio 0.65 +/- 0.19. Statistically significant differences were found among the three groups for these parameters. In spite of the wide distribution and overlap of the values of optic disc parameters among the three groups, normal subjects with an optic disc area of greater than or equal to 3.0mm2 showed clear differences in optic disc parameters compared to ocular hypertensive and glaucoma cases. From these results, cases with larger discs seem to be more vulnerable to raised IOPs.

Glaucoma, Open-Angle↗
PubMed1990

One-step sandwich enzyme immunoassay for human laminin using monoclonal antibodies.

A one-step sandwich enzyme immunoassay (one step sandwich EIA) for human serum immunoreactive laminin was set up with a pair of monoclonal antibodies prepared against human placental laminin P1 fragment. The assay was characterized by carrying out two immunoreactions simultaneously, laminin P1 fragment reacting with both a monoclonal antibody as a solid phase and a horseradish peroxidase-labeled monoclonal antibody (Fab') against human laminin P1 fragment as conjugate. Sensitivity of the immunoassay was 0.01 ng/well (0.5 microgram/l), and linearity was obtained between 0.01-20 ng/well (0.5-1,000 micrograms/l). The levels of laminin in sera from normal individuals and patients with liver cirrhosis, hepatocellular carcinoma and primary biliary cirrhosis were 103 +/- 15 micrograms/l, 228 +/- 70 micrograms/l, 341 +/- 163 micrograms/l and 232 +/- 93 micrograms/l, respectively. Protein immunoblotting showed that the serum immunoreactive laminin measured by the assay was a fragment with rel mol mass of 200 kDa.

Antibodies, Monoclonal↗
PubMed1990

Rapid one-step sandwich enzyme immunoassay for tissue inhibitor of metalloproteinases. An application for rheumatoid arthritis serum and plasma.

A 1 h, one-step sandwich enzyme immunoassay was set up with a pair of monoclonal antibodies prepared against bovine tissue inhibitor of metalloproteinases (TIMP). TIMP in samples was allowed to react simultaneously with both solid-phase antibody and peroxidase-labeled Fab' of another antibody. Minimum sensitivity was 1 pg/well for bovine TIMP and 1.5 pg/well for human TIMP. The TIMP level in the sera of 38 rheumatoid arthritis (RA) patients (241 +/- 53 ng/ml, mean +/- SD) was significantly higher (P less than 0.001) than the level in the sera of 81 healthy subjects (175 +/- 39). A similar significant difference (P less than 0.001) was observed between the TIMP level in platelet-poor plasma of normal subjects (64 +/- 10) and that of RA patients (84 +/- 23), suggesting that the increase in TIMP seen in RA sera can not be ascribed merely to an increase in platelet-derived TIMP.

Arthritis, Rheumatoid↗
PubMed1990

Input-output relationships in the jaw and orofacial motor zones of the cat cerebral cortex.

Input-output relationships of the jaw and orofacial motor zones in the cerebral cortex of lightly anesthetized cats were studied. These relationships were examined by studying the motor effects produced by intracortical microstimulation (ICMS) and recording from single neuron. Jaw and orofacial motor effects were evoked by ICMS of the anterior part of the coronal and lateral sigmoid gyri (C-S motor zone) and the lateral wall of the presylvian sulcus (P motor zone). ICMS of the P motor zone produced more complex movements than that of the C-S motor zone. Repetitive stimulation of the P motor zone also evoked rhythmic jaw movements. Almost all cortical cells located in the C-S motor zone responded to tactile stimulation of cutaneous skin of the orofacial regions or the tooth, whereas those of the P motor zone received no cutaneous input from the orofacial regions. Cytoarchitectonically, the C-S motor zone was restricted to areas 3a, 6a beta and occasionally to area 4 gamma, whereas the P motor zone was represented to area 6a beta. Therefore, it is concluded that the C-S motor zone might be involved in sensorimotor integration of the jaw and orofacial motor functions, whereas the P motor zone might function only as a command area for jaw and orofacial movements.

Animals↗
PubMed1990

Concanavalin A- and fetal-calf-serum-induced rounding and myosin light chain phosphorylation in cultured smooth muscle cells.

Rabbit aorta smooth muscle cells (SMC) in long-term culture retracted in less than 10 min in response to a sequential order of stimulations by concanavalin A (Con A) and fetal calf serum (FCS). With additional continuous stimulation by FCS, the SMC took on a circular shape and were anchored to the substrate by retraction fibrils. This rounding was observed only when the cells were sequentially stimulated by Con A and FCS. Depletion of intracellular Ca2+ stores by the addition of EGTA and Ca2+ ionophores inhibited the rounding. Transient phosphorylation of MLC20 was observed in the initial stage during the SMC rounding. The extent of monophosphorylated MLC20 increased for up to 5 min to a maximal value of 49%. The diphosphorylated form reached a maximal value of 29% within 2 min; then both forms of MLC20 decreased. The process of the SMC rounding was inhibited by antimycin A or cytochalasins, in a dose-dependent manner, findings which suggested a dependency on both metabolic energy and actin-containing microfilaments. The smooth-muscle-relaxing agent, HA1077, also inhibited the process of SMC rounding. These observations suggest that a cellular contractile process might be involved in rounding of SMC.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Comparative morphological and biological studies on the itraconazole- and ketoconazole-resistant mutants of Cryptococcus neoformans.

Studies were carried out on the resistance in vitro of Cryptococcus neoformans to the oral antifungal drugs itraconazole and ketoconazole. None of the six sensitive strains tested developed resistance to itraconazole or ketoconazole by serial transfer on Sabouraud's glucose agar plates containing increasing concentrations of either drug. One mutant resistant to itraconazole, and one mutant resistant to ketoconazole, were isolated from the progenies of yeast cells surviving after treatment with a mutagenic substance, N-methyl-N'-nitro-N-nitroso-guanidine. These mutants were capable of growing in the presence of high concentrations of the drugs to which they were resistant. The itraconazole- and ketoconazole-resistant mutants obtained by mutagenesis were compared morphologically and biologically. The itraconazole-resistant mutant was characterized by the formation of very rough colonies which varied in size and shape, production of a large number of cell clusters, complete loss of capsule formation, and major degenerative changes in the cells, while in the ketoconazole-resistant mutant these changes were less pronounced and no cell clusters were formed. The acquisition of resistance was more stable in the itraconazole-resistant mutant than in the ketoconazole-resistant mutant. Both mutants showed partial cross-resistance and complete loss of virulence for mice.

Animals↗
PubMed1990

Long-term efficacy of low power argon laser trabeculoplasty.

We studied the long-term efficacy of argon laser trabeculoplasty, applying low-power (a mean of 450 mW), a duration of 0.1 second, and a small number of burns (a mean total energy of 1.85 J) over 90 to 120 degrees of the trabecular meshwork. Fifty-four eyes with poorly controlled open-angle glaucoma were treated. The mean follow-up was 46 months. The mean intraocular pressure decrease was 5.3 mmHg in 35 eyes at one year, 6.1 mmHg in 23 eyes at 3 years, 5.1 mmHg in 13 eyes at 5 years, and 5.4 mmHg in 5 eyes at 6 years. Life-table analysis showed that the probability of success was 58% at one year, 49% at 3 years, and 46% at 5 years. Both the incidence and magnitude of the intraocular pressure rise in the early post-laser period were minimal and no serious complications were observed.

Aged↗
PubMed1990

Distribution and response properties of cat SI neurons responsive to changes in tooth temperature.

1. The activity of 214 tooth pulp-driven neurons (TPNs) in the primary somatosensory cortex (SI) activated by electrical stimulation of the canine tooth pulp was studied in anesthetized cats. These neurons were tested for their responses to thermal stimulation of the tooth pulp. 2. One hundred fifty-five TPNs were not responsive to changes in tooth temperature (thermally insensitive, TINS-TPNs) and 59 TPNs were responsive (thermally sensitive, TS-TPNs: 38 TS-TPNs were heat sensitive and 21 were cold sensitive). TS-TPNs were also tested for responsiveness to mechanical and thermal stimulation of the skin, mucosa, or periodontal membrane. Each TS-TPN was classified on the basis of cutaneous, mucosal, or periodontal mechanical receptive-field properties as either low-threshold mechanoreceptive (LTM: 57%), wide dynamic range (WDR: 25%), nociceptive specific (NS: 10%) or pulp specific (PS: 8%). 3. TS-TPNs were distributed in an upper bank of the orbital sulcus of SI. The majority were located in laminae III (32%) and IV (60%) of area 3b. 4. Heat-sensitive LTM, WDR, PS TS-TPNs, and cold-sensitive LTM TS-TPNs were characterized by a rapid rise in firing rate during thermal stimulation of the tooth pulp. In contrast, heat-sensitive NS and cold-sensitive NS and PS TS-TPNs responded with a slow rise in firing frequency during thermal stimuli delivered to the tooth pulp. 5. A linear regression analysis was applied to the stimulus-response functions of neuronal discharges of TS-TPNs. Fifty-six percent of heat-sensitive LTM, WDR, and cold-sensitive LTM TS-TPNs showed statistically significant relation (P less than 0.5) between peak firing frequency and stimulus temperature and increasing firing frequency after increases in stimulus temperature, whereas heat-sensitive and cold-sensitive NS and PS TS-TPNs did not show a clear increase in firing frequency during the thermal stimulus. 6. These findings suggest that heat-sensitive LTM and WDR TS-TPNs and cold-sensitive LTM TS-TPNs that showed high regression coefficients in stimulus-response function may be involved in encoding the intensity of noxious thermal stimulation of the tooth pulp.

Animals↗
PubMed1990

Visual disturbance in patients with melanocytoma of the optic disk.

Visual disturbance in 11 patients with melanocytoma of the optic disk was analyzed. Goldmann visual field examination showed enlargement of Mariotte's blind spot in 7 of 10 patients (70%) and visual field defect or depression in 7 patients (70%). In 6 of the 7 patients with visual field defect of depression (86%), the portion of visual field damage corresponded with the location of the tumor and retinal nerve fiber bundle defect. In 1 patient, sudden loss of visual acuity occurred, presumably due to anterior ischemic optic neuropathy induced by melanocytoma.

Adult↗
PubMed1990

Community people's preference of hand drawn face graph as a health informing device.

Although the cartoon of a face is an effective device to visualize the image of numerical indices, its use is not popular among community health personnel. In the present study, we used the face graph as an aid for health informing and educating activities in the setting of a community health activity. For this purpose, we designed a special sheet to draw face by hand. By using this sheet, each person can draw his/her 'face' from one's laboratory data index under the guidance of additional lines. The acceptability of this hand drawn face was evaluated by 283 people aged 65 years and over at a health counseling session. For both men and women, a higher percentage preferred face (37% for men, 40% for women) over numeral (23% for men, 17% for women). The preference for the face graph was also observed at each of three age groups within each sex. The highest affinity to face (64%) was observed for the 14 women who reported as cataract patients.

Aged↗
PubMed1990

Alterations in Na(+)-K(+)-ATPase activity and beta-endorphin content in acute ischemic brain with and without naloxone treatment.

The Na(+)-K(+)-adenosine triphosphatase (Na(+)-K(+)-ATPase) activity and beta-endorphin immunoreactivity were determined in rat brain at the acute stage of ischemia produced by unilateral occlusion of the middle cerebral artery (MCA). The effect of pretreatment with naloxone on these activities was also evaluated in the same model. After MCA occlusion, Na(+)-K(+)-ATPase activity was promptly reduced in the ischemic hemisphere and remained at a lower level than in the contralateral hemisphere during 90 minutes of ischemia. A single intraperitoneal 0.5-mg injection of naloxone prior to MCA occlusion attenuated the inactivation. On the other hand, beta-endorphin immunoreactivity was significantly increased following ischemia. The increase was marked in the ischemic hemisphere and was also observed in the contralateral hemisphere; this increase was not affected by the administration of naloxone. These results indicate the possibility that naloxone contributes to protecting the brain from ischemia through stabilizing the cellular membrane. The possible mechanism by which naloxone attenuates the inactivation of Na(+)-K(+)-ATPase in the ischemic brain is discussed in view of alterations of the central beta-endorphin system during ischemia.

Acute Disease↗
PubMed1990

Effects of Spirulina platensis on plasma lipoprotein lipase activity in fructose-induced hyperlipidemic rats.

The effects of Spirulina platensis on lipoprotein lipase activity and hepatic triglyceride lipase activity in post-heparin plasma were studied in fructose-induced hyperlipidemic rats. Male Wistar rats aged 3 weeks old (body weight, 54 g) were fed on the high-fructose diet (68%) or the high-fructose diets containing Spirulina at the level of 5, 10, and 15%, respectively, for 4 weeks. The dietary hyperlipidemia caused by the high-fructose diet was improved by Spirulina feeding, accompanied by a significant increase in the lipoprotein lipase activity in post-heparin plasma.

Animals↗