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Biomedical subjects

K Oie

Publications and source records attributed to K Oie.

10 recordsLinked to original sources
PubMed1998

The structure of somatosensory information for human postural control.

The goal of the present study was to determine the properties of the somatosensory stimulus that alter its temporal coupling to body sway. Six standing subjects were tested while touching a metal plate positioned either directly in front of or lateral to the subject. In each condition, the plate moved 4 mm at 0.2 Hz in either the medial-lateral (ML) or anterior-posterior direction (AP). The results showed that coupling between body sway and touch plate movement was strongest when the touch plate moved in a direction along the longitudinal axis of the arm. Coupling strength was weaker when the touch plate moved perpendicular to the longitudinal axis of the arm. The results consistently show that a radial expansion stimulus was more effective than a lamellar-type stimulus at the fingertip. Moreover, somatosensory information from a surface is interpreted in terms of the orientation of the contact limb and the potential degrees of freedom available through its movement.

Adult↗
PubMed1998

Position and velocity coupling of postural sway to somatosensory drive.

Light touch contact of a fingertip to a stationary surface provides orientation information that enhances control of upright stance. Slight changes in contact force at the fingertip lead to sensory cues about the direction of body sway, allowing attenuation of sway. In the present study, the coupling of postural sway to a moving contact surface was investigated in detail. Head, center of mass, and center of pressure displacement were measured as the contact surface moved rhythmically at 0.1, 0.2, 0.4, 0.6, and 0.8 Hz. Stimulus amplitude decreased with frequency to maintain peak velocity constant across frequency. Head and body sway were highly coherent with contact surface motion at all frequencies except 0.8 Hz, where a drop-off in coherence was observed. Mean frequency of head and body sway matched the driving frequency </=0.4 Hz. At higher frequencies, non-1:1 coupling was evident. The phase of body sway relative to the touch plate averaged 20-30 degrees at 0.1-Hz drive and decreased approximately linearly to -130 degrees at 0.8-Hz drive. System gain was approximately 1 across frequency. The large phase lags observed cannot be accounted for with velocity coupling alone but indicate that body sway also was coupled to the position of the touch plate. Fitting of a linear second-order model to the data suggests that postural control parameters are not fixed but adapt to the moving frame of reference. Moreover, coupling to both position and velocity suggest that a spatial reference frame is defined by the somatosensory system.

Adaptation, Physiological↗
PubMed1997

Comparison of chemical characteristics of the first and the second cysteine-rich domains of protein kinase C gamma.

Protein kinase C (PKC) is a key enzyme family involved in cellular signal transduction. The binding of endogenous diacyl glycerol (DAG) to the cysteine-rich domain (CRD) of PKC is associated with normal cell signaling and function. In contrast, the binding of exogenous phorbol esters to the CRD of PKC is considered to be a key initiating event in tumor promotion. Conventional PKC isozymes (PKC alpha, beta I, beta II, and gamma) contain two CRDs, both of which are candidates for the phorbol ester binding site. In order to elucidate the binding requirements of phorbol esters and to obtain information on the phorbol ester binding site in native PKC gamma, several key chemical characteristics of the first and the second CRDs consisting of ca. 50 amino acids of rat PKC gamma (gamma-CRD1 and gamma-CRD2) were examined. In the presence of Zn2+ and phosphatidylserine (PS), both CRDs gave similar Kd values (65.3 nM for gamma-CRD1, 44.1 nM for gamma-CRD2) in phorbol 12,13-dibutyrate (PDBu) binding assays. In comparison, the binding affinity of PDBu for native rat PKC gamma was found to be 6.8 nM. Zn2+ was shown to play an important role in the folding and PDBu binding of both CRDs. A Zn(2+)-induced conformational change was observed for the first time by CD spectroscopic analysis of the complexed and uncomplexed CRDs. Relative to the pronounced Zn2+ effect, most divalent first row transition metal ions along with Ca2+, Mg2+, and Al3+ were ineffective in folding either CRD. Notably, however, Co2+ exhibited a gamma-CRD1-selective effect, suggesting that metal ions, not unlike extensively used organic probes, might also become effective tools for controlling isozyme selective activation of PKC. Moreover, group Ib (Cu2+ and Ag+) and group IIb element ions other than Zn2+ (Cd2+ and Hg2+) were found to abolish PDBu binding of both CRDs. Importantly, these inhibitory effects of Cu2+, Ag+, and Cd2+, and Hg2+ were also observed with native PKC gamma. These results indicate that recent reports on the modulation of conventional PKC by heavy metal ions could be explained by their coordination to the CRDs. While the similar affinities of gamma-CRD1 and gamma-CRD2 for PDBu suggest that either site qualifies as the PDBu binding site, new molecular probes of these CRD3 have now been identified that provide information on the preferred site. These novel ligands (5a and 5b) were synthesized by aza-Claisen rearrangement of (-)-N13-desmethyl-N13-allylindolactam-G (4). These compounds did not significantly affect the specific PDBu binding of gamma-CRD1 but did inhibit that of gamma-CRD2 with similar potency to (-)-indolactam-V. Moreover, these new probes did not significantly inhibit the PDBu binding of native PKC gamma. (-)-Indolactam-V itself bound almost equally to gamma-CRD1, gamma-CRD2, and native PKC gamma. These results suggest that the major PDBu binding site in native PKC gamma is the first CRD, not the second CRD, unlike the novel PKCs.

Amino Acid Sequence↗
PubMed1981

[A case of CNS sarcoidosis -case report of hydrocephalus due to mechanical obstruction secondary to sarcoid granulomata at the outlet of the fourth ventricle (author's transl)].

A 28-year old male was admitted to Musashino Red Cross Hospital on June 21, 1975, because of symptoms of increased intracranial pressure and cerebellar dysfunction. Thirteen months prior to admission he had a mild fever, tremor of right arm, headache, nausea and unsteady gait, but made a gradual recovery in about 40 days. A month prior to admission he had unsteady gate again wit dizziness, photophobia and lacrimation. Gait disturbance aggravated and he was admitted to another hospital, where he developed recent memory disturbance and cloudiness of consciousness. Spinal tap revealed initial pressure of 280 mm CSF. So a mass lesion possibly in the posterior fossa was suspected and the patient was referred to the neurosurgical department of musashino Red Cross Hospital. On admission he was moderately disorientated and disturbed in recent memory. Wide based gait, horizontal and vertical nystagmus were also noted. Angiography revealed rounding of the curve of the pericallosal artery but no space occupying lesions. External ventricular drainage was performed on July 25, 1975. After the operation, his orientation improved without change in dizziness, nystagmus and recent memory disturbance. Ventriculography showed hydrocephalus with cisternography revealed a block at the basal cisterns. PPDs was negative and typical sarcoid tubercles were found in the biopsy specimen of the cervical lymphnode. Kveim test was positive. But repeated chest roentgenogram failed to show bilateral hilar lymphadenopathy, or other changes consistent with pulmonary sarcoidosis. Steroid therapy resulted in marked symptomatic improvement.

Adult↗
PubMed1978

Sequential delayed enhanced CT in brain tumors.

Delayed enhanced CT was performed in 53 cases and these findings are compared with those of delayed radioisotope scan and with operative and histopathologic findings. We have classified the results of enhancement into four types as follows: (1) immediate enhancement pattern due to rich vascular bed, typical in meningiomas; (2) delayed enhancement pattern due to exudation, often seen in cystic astrocytomas; (3) intermediate sustained pattern due to both mechanisms in glioblastoma multiforme; (4) no enhancement pattern as in diffuse astrocytomas. The results of delayed enhanced CT correlated well with those of radioisotope scan.

Brain Neoplasms↗
PubMed1978

[Radioisotope cisternographic study on intracranial arachnoid cyst (author's transl)].

The dynamics of the CSF circulation in six cases of intracranial arachnoid cysts was examined by RI cisternography suing 0.5 to 1.0 mCi of 169Yb DTPA or 50 to 100 microCi of 131I HSA injected into the lumbar subarachnoid space. Serial scintigrams were obtained with rectilineal scintillation scanner at 2, 4, 6, 24 and 48 hours after injection. The communication of the cavity of arachnoid cyst and subarachnoid space was recognized in all cases. The cysts were best visualized at 24 hours in most cases. Four patterns of the entry and stasis of RI in cysts were observed as follows, 1) rapid filling of RI into the cyst and delayed clearance, 2) both rapid filling and clearance, 3) slow filling and delayed clearance, 4) no filling.

Adolescent↗