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Biomedical subjects

T Arima

Publications and source records attributed to T Arima.

At least 217 records · Page 12Linked to original sources
PubMed1991

Tumor necrosis factor-beta in the serum of adult T-cell leukemia with hypercalcemia.

Serum tumor necrosis factor-beta (TNF-beta) from patients with adult T-cell leukemia (ATL) was studied by a sandwich enzyme-linked immunosorbent assay (ELISA) developed in our laboratory using biotinylated monoclonal anti-TNF-beta and recombinant TNF-beta. Seven of eight patients with hypercalcemia showed elevation of serum TNF-beta. On the other hand, TNF-beta could not be detected by the ELISA in 28 patients without hypercalcemia. The lower detection limit in this assay was 100 pg/mL, corresponding to 500 pg/mL by the conventional method. In two patients serum TNF-beta level decreased after treatment in association with the level of serum calcium. Furthermore, immuno-staining using anti-TNF-beta and avidin-biotin complex showed the presence of cytoplasmic TNF-beta in not only human T-cell leukemia virus type I infected cell lines, but also freshly isolated cells from ATL patients with hypercalcemia. The actual biologic activity of TNF-beta in serum was confirmed by a conventional bioassay in a patient with hypercalcemia, and its cytotoxic activity was inhibited by the addition of anti-TNF-beta antibody in the assay. These results suggested that serum TNF-beta might be one of the factors contributing to the hypercalcemia, at least in patients with ATL.

Adult↗
PubMed1991

Filter characteristics of cercal afferents in the cockroach.

The response dynamics of cercal afferents in the cockroach. Periplaneta americana, were determined by means of a cross-correlation technique using a Gaussian white noise modulation of wind as a stimulus. The white noise stimulus could evoke sustained firing activity in most of the afferents examined (Fig. 1). The spike discharges were unitized and then cross-correlated with the stimulus to compute 1st- and 2nd-order Weiner kernels. The 1st-order kernels from a total of 28 afferents were biphasic and closely matched the time differential of a pulse (Figs. 1, 3 and 4). The amplitude and waveform of the kernels depended on the stimulus angle in such a way that the kernels were the mirror image of those on the polar opposite side (Figs. 2 and 3). The 2nd-order kernels were also differential. They had 2 diagonal peaks and 2 off-diagonal valleys in a 2-dimensional plot with 2 time axes (Figs. 1, 5 and 6). This 4-eye configuration was basically invariant irrespective of the stimulus angle, although the kernels varied in amplitude when the stimulus angle was changed. The time between the peak and a following trough of the 1st-order kernel was constant and had a mean of 4.6 +/- 0.1 ms, whereas the time between 2 diagonal peaks of the 2nd-order kernels was 4.7 +/- 0.1 ms (Figs. 4 and 6), suggesting that wind receptors (filiform sensilla) on cerci act as a band-pass filter with a peak frequency of about 106 Hz. The peak time, however, varies from 2.3 to 6.9 ms in both kernels, which may reflect the spatial distribution of the corresponding hairs on the cercus. The summation of the 1st- (linear) and 2nd-order (nonlinear) models precisely predicted the timing of the spike firing (Fig. 8). Thus, these 2 lower-order kernels can totally characterize the response dynamics of the wind receptors. The nonlinear response explains the directional sensitivity of the sensory neurons, while the differentiating 1st-order kernel explains the velocity sensitivity of the neurons. The nonlinearity is a signal compression in which one of the diagonal peaks of the 2nd-order kernel always offsets the downward phase of the 1st-order kernel (Fig. 7) and obviously represents a half-wave rectification property of the wind receptors that are excited by hair movement in only one direction and inhibited by hair movement in the polar opposite direction.

Animals↗
PubMed1991

White noise analysis of graded response in a wind-sensitive, nonspiking interneuron of the cockroach.

1. A novel approach using a Gaussian white noise as stimulus is described which allowed quantitative analysis of neuronal responses in the cercal system of the cockroach, Periplaneta americana. Cerci were stimulated by air displacement which was modulated by a sinusoidal and a white noise signal. During the stimulation, intracellular recordings were made from a uniquely identifiable, nonspiking, local interneuron which locates within the terminal abdominal ganglion. The white noise stimulation was cross-correlated with the evoked response to compute first- and second-order kernels that could define the cell's response dynamics. 2. The interneuron, cell 101, has an exceptionally large transverse neurite that connects two asymmetrical dendritic arborizations located on both sides of the ganglion. 3. The first-order Wiener kernels in cell 101 were biphasic (differentiating). The waveforms of the kernels produced by the ipsilateral and contralateral stimulations were roughly mirror images of each other: the kernels produced by wind stimuli on the side ipsilateral to the cell body of the interneuron are initially depolarized and then hyperpolarized, whereas those on the other side are initially hyperpolarized. The polarity reversal occurred along the midline of the animal's body, and no well-defined kernel was produced by a stimulus directed head on or from the tail. 4. Mean square error (MSE) between the actual response and the model prediction suggests that the linear component in cell 101 comprises half of the cell's total response (MSEs for the linear models were about 50% at preferred directions), whereas the second-order, non-linear component is insignificant. The linear component of the wind-evoked response was bandpass with the preferred frequency of 70-90 Hz. 5. Accounting for a noise, we reasonably assumed that at high frequencies the graded response in cell 101 is linearly related to a modulation of the air displacement and sensitive to the rate of change of the signal (i.e., wind velocity) and the direction of its source. It is suggested that the dynamics of the first-order kernel simply reflect the dynamics of sensory receptors that respond linearly to wind stimulation.

Acoustic Stimulation↗
PubMed1991

Quick-freeze, deep-etch visualization of the 'cytoskeletal spring' of cochlear outer hair cells.

The lateral membrane system of the cochlear outer hair cell, consisting of the lateral plasma membrane, pillars, filamentous lattice and subsurface cisternae, is considered to be involved in the contractile movement of the isolated cochlear outer hair cell. The filamentous lattice, called the cytoskeletal spring, has been identified in the demembranated cochlear outer hair cell treated with the detergent Triton X-100. In this study, the quick-freeze, deep-etch method was applied to demonstrate the three-dimensional organization of both the filamentous and membranous structures of the lateral membrane system of cochlear outer hair cells. Treatment with saponin revealed that the inner leaflet of the lateral plasma membrane of the cochlear outer hair cell possesses more membrane particles than the outer leaflets, and that the pillars are closely associated with membrane particles in the inner leaflet of the lateral membrane. The presence of filamentous bridges between the filamentous lattice and the subsurface cisternae was also detected. We propose that the lateral membrane system in the cochlear outer hair cell may play an important role in the tuning mechanisms within the cochlea in normal hearing.

Animals↗
PubMed1991

Sequence analysis of the putative structural genes of hepatitis C virus from Japanese and European origin.

cDNA fragments encoding the putative structural genes of the hepatitis C genome were isolated from a plasma pool of Japanese non-A, non-B hepatitis patients and from sera of individual Spanish patients. From the Japanese plasma pool a series of E1 clones was obtained that showed 88-98% homology among each other, both at the nucleotide and amino acid level. Compared to the sequences published by the Chiron Corporation and Takeuchi et al., the amino acid homology was 75-79% and 91-94%, respectively. Analysis of the core and E2/NS1 genes showed a high conservation of the core sequence and a high sequence variation in the 5' end of the E2/NS1 gene. The E1 gene of one Spanish isolate showed greater homology to the Chiron than to the Japanese sequence. Another Spanish isolate was more homologous to the Japanese sequence indicating that both hepatitis C genotypes are present in Europe. Analysis of the E1 gene of an isolate derived from a single patient with a 5-year interval revealed nine nucleotide and five amino acid changes.

Amino Acid Sequence↗
PubMed1991

Remnant valve of inferior vena cava dislodged by Swan-Ganz catheter.

We experienced a rare case of a patient with acute myocardial infarction. It was rare in that a piece of tissue, probably a remnant valve of the inferior vena cava in the right atrium, was dislodged by the Swan-Ganz catheter during a right heart catheterization study in the chronic phase of the disease. As far as we know, no other such case has been reported. Such remnants are considered to be present in 2 to 3% of the general population. Therefore, it is necessary to determine the presence or absence of a remnant before cardiac catheterization and to modify the procedure, such as by changing the catheter's approach, when a remnant is present.

Aged↗
PubMed1991

Ultrastructure of the guinea pig cochlear aqueduct. An electron microscopic study of decalcified temporal bones.

The ultrastructure of the guinea pig cochlear aqueduct was examined using semi-thin and thin sections. The lumen of the cochlear aqueduct was occupied by a sparse meshwork of fibroblasts and delicate connective tissue trabeculae. The periotic tissue lining the bony wall of the aqueduct was composed of multiple layers of both elongated cells and densely arranged laminae of collagen fibrils. These structures were identical to those of the dura mater and the arachnoid. The opening to the perilymphatic space of the scala tympani also contained connective tissue trabeculae, but the arrangement of fibroblasts was more compact here than in the main part of the duct. These structural features suggest that fluid can move freely through cochlear aqueduct, and that the effects of sudden pressure changes in the CSF may be protected against by the densely and perpendicularly arranged fibroblast at the opening to the perilymphatic space.

Animals↗
PubMed1991

Computer-aided three-dimensional reconstruction of guinea pig cochlear aqueduct.

A computer-aided method of three-dimensional reconstruction was applied to the determination of the overall spatial configuration of the guinea pig cochlear aqueduct. The rotation function of the reconstructed images was useful in showing the individual small parts of the duct. A semi-translucent display of the segmental reconstruction of the duct demonstrated a difference in the density of the cellular components between the opening to the perilymphatic space and the duct portion. We propose that the cochlear aqueduct serves as a protective mechanism against a sudden change in CSF pressure in the subarachnoid space.

Animals↗
PubMed1991

[Early phase II study of MST-16 (sobuzoxane) on malignant lymphoma].

Early phase II study of MST-16[4,4-(1,2-ethanediyl) bis (1-isobutoxycarbonyloxy-methyl-2, 6-piperazinedione], a derivative of ICRF-154, on malignant lymphoma was conducted by multi-institutional cooperative group. MST-16 was administered orally at doses of 1,600 mg/body/day for 5 days or 1,200 mg/body/day for 10-14 days, mainly. The number of registered and evaluated patients were 29 and 28, respectively (Hodgkin's disease 3 patients and non-Hodgkin lymphoma 25). Twenty-seven of 28 patients had received prior chemotherapy and/or radiation therapy. Of 28 evaluable patients, overall response rate (CR + PR) was 32.1%. In high-dose administration group, the response rate was not significantly high. The response rate seemed to be high in patients who were treated repeatedly (number of courses greater than 3). Major side effects observed were myelosuppression and gastro-intestinal disorders which were reversible in a rest period. Myelosuppression seemed to be severe in high-dose administration group. This study indicated that MST-16 was a useful agent against malignant lymphoma including primary resistant or relapsed patients, and that the recommended regimen for a late phase II study was considered to be 1,600-2,400 mg/body/day for 5-7 days repeatedly with a pause of several days. Furthermore, the study should be considered at the dose of 3,200 mg/body because half cases administered at this dose showed some response.

Adult↗
PubMed1990

Expression of the multidrug transporter, P-glycoprotein, in acute leukemia cells and correlation to clinical drug resistance.

The overexpression of a cell-surface glycoprotein termed P-glycoprotein (P-gp) is frequently associated with multi-drug resistance (MDR) in cell lines in vitro. To evaluate the implications of P-gp expression in clinical drug resistance, the authors examined the expression of P-gp in leukemia cells from patients with acute myelogenous leukemia (AML) and those with acute lymphoblastic leukemia (ALL) at initial presentation and relapse, using immunoblotting with a monoclonal antibody against P-gp, C219. Nine of 17 patients with AML and four of 11 patients with ALL had P-gp-positive results at the initial presentation, and most P-gp-positive patients did not respond to chemotherapy. Four of seven patients at the relapsed stage and all three patients with preceding myelodysplastic syndrome had P-gp-positive results. The expression of P-gp and clinical refractoriness to chemotherapy were highly correlated. These data indicate that the expression of P-gp is closely related to clinical drug resistance in acute leukemia.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1990

The ultrastructure of the supporting system in the guinea pig semicircular canal.

The ultrastructure of the perilymphatic space of the guinea pig semicircular canal was examined, using thin sectioning, scanning electron microscopy and freeze-fracture methods. The perilymphatic space was divided into two parts: an area of fibrous matrix and an area of fibroblasts with bundles of fine filaments. In the area of fibroblasts, cell processes and filament bundles formed a meshed pattern. The cell processes were interconnected with each other by both intermediary and gap junctions. The inner surface of the osseous semicircular canal was covered with multilayers of cell processes of both fibroblasts and mesothelial cells. The fact that tight and gap junctions were observed between the cell processes suggests a functional significance in these structures.

Animals↗
PubMed1990

Ciliary ultrastructure in a child with Kartagener's syndrome. A transmission electron microscopic study using tannic acid staining.

Kartagener's syndrome has been characterized by a primary ultrastructural abnormality of the cilia which consequently impairs their movements. We used transmission electron microscopy with tannic acid staining to investigate the fine structure of the cilia from the nasal mucosa of a 7-year-old girl with Kartagener's syndrome. The staining technique employed was useful for visualizing the dynein arms and protofilaments of the microtubules of the cilia. Although 15% of the cilia examined demonstrated microtubular disarrangements, these findings were considered to be acquired changes due to chronic sinusitis. No abnormal ciliary ultrastructures specific to Kartagener's syndrome, such as absence of dynein arms, were detected in this study. In such cases without any abnormal ciliary ultrastructures, it is conceivable that some other unknown factor may be involved in the impaired ciliary movement.

Actin Cytoskeleton↗