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Biomedical subjects

T Yuasa

Publications and source records attributed to T Yuasa.

At least 91 records · Page 5Linked to original sources
PubMed1998

Alteration of circadian time structure of blood pressure caused by night shift schedule.

The effects of night shift schedules on circadian time structure of blood pressure were studied in seven healthy young subjects by continuous monitoring of blood pressure every 30 min for 72 h. In the control experiment, subjects were instructed to sleep at regular times with the light off at 00.00 h and the light on at 07.00 h. In the shift experiment, they were instructed to go to bed at 06.00 h and wake up at 11.00 h. The circadian rhythm of blood pressure rapidly phase delayed by 3.5 h in the second night shift day as a group phenomenon. Individual differences in changes in power spectral patterns of blood pressure were found in the night shift schedule. Ultradian rhythmicity of blood pressure was more pronounced in three subjects, whereas the circadian rhythmicity was maintained in four subjects. These findings held when the adaptation to shift work was taken into account.

Adult↗
PubMed1998

Expression of uroplakin Ib and uroplakin III genes in tissues and peripheral blood of patients with transitional cell carcinoma.

Uroplakins (UPs), urothelium-specific transmembrane proteins, are present only in urothelial cells. We have determined the nucleotide sequences of human UP-Ib and UP-III and synthesized specific primer pairs. The two UP genes were expressed in both cancerous and noncancerous urothelial taken from all patients examined by reverse transcription-polymerase chain reaction (RT-PCR). These genes were also detected in the peripheral blood of 3 patients with metastatic transitional cell carcinoma (TCC), but not in that from 9 patients with non-metastatic TCC or 3 healthy volunteers. The sensitivity of our assay was sufficient to detect one cancer cell in 5 ml of peripheral blood. Detection of UP gene-expression in blood by RT-PCR may provide helpful information for the diagnosis and management of TCC.

Adult↗
PubMed1998

Antitumor killer lymphocytes in the peripheral blood of a patient with transitional cell carcinoma of the bladder.

BACKGROUND: Peripheral blood lymphocytes (PBL) from patients with bladder cancer also contain cells possessing cytotoxic activity against autologous tumor cells. These cells are phenotypically heterogenous and include natural killer (NK) and cytotoxic T cells. This study investigated the role of cytotoxic lymphocytes directed against autologous bladder cancer cells. METHODS: PBL were obtained at intervals before and after surgery and analyzed for cytotoxic activity against autologous bladder cancer cells in 4-hour 51Cr release assay. PBL stimulated with autologous tumor cells were also transformed with human T-lymphotropic virus type-1, establishing a cell line (KB31) which was analyzed for phenotype and cytotoxic activity against the autologous tumor cells. RESULTS: PBL preoperative cytotoxic activity was low, but increased after surgery. Cytotoxic activity was found not only against autologous bladder cancer cells, but also against heterologous bladder cancer (KK-47) and myeloid leukemia (K562) cells, with the highest activity against the heterologous cell lines. The cytotoxic activity of KB31 was 40% against autologous tumor cells 6 weeks after initiation of the cell line, but decreased to 5% by 6 months. This activity was lower than that against the other cell lines, and was similar to that of PBL in short-term culture. Fluorescence-activated cell sorter (FACS) analysis demonstrated that in KB31 cells at 6 weeks, CD8+ cells were dominant, but CD56+ cells predominated at 6 months. CONCLUSION: These results suggest that the presence of cytotoxic activity in the peripheral blood of the patient was due to both cytotoxic T cells and NK cells. The cytotoxic activity was lowest prior to surgery and increased postoperatively.

Aged↗
PubMed1998

Electrophysiological features of central motor conduction in spinocerebellar atrophy type 1, type 2, and Machado-Joseph disease.

OBJECTIVES: To characterise electrophysiologically the central motor conduction of spinocerebellar atrophy type 1 (SCA1), type 2 (SCA2), and Machado-Joseph disease (MJD). METHODS: Motor evoked potentials (MEPs) triggered by transcranial magnetic stimulation (TMS) was used to investigate the functions of corticospinal tracts of 10 patients with SCA1, 10 with MJD, and eight with SCA2 in addition to pathological study of the spinal cord in a patient with SCA1. RESULTS: Central motor conduction time (CMCT) was extremely prolonged and the MEP threshold increased in all patients with SCA1, whereas both were normal in patients with SCA2 or MJD. The MEP size in MJD was larger than normal, but was normal in SCA1 and SCA2. A pathological investigation of the corticospinal tract of the spinal cord of a patient with SCA1 showed selective loss of large diameter fibres. CONCLUSIONS: SCA1, SCA2, and MJD differ in their pathophysiological features of the central motor tract and can be differentiated from each other by MEP values for the lower limb muscles, even though their neurological symptoms are sometimes similar.

Adult↗
PubMed1998

Spectral analysis of heart rate, arterial pressure, and muscle sympathetic nerve activity in normal humans.

We investigated the frequency components of fluctuations in heart rate, arterial pressure, respiration, and muscle sympathetic nerve activity (MSNA) in 11 healthy women using an autoregressive model and examined the relation among variables using Akaike's relative power contribution analysis with multivariate autoregressive model fitting. Power spectral analysis of MSNA revealed two peaks, with low-frequency (LF) and high-frequency (HF) components. The LF component of MSNA was a major determinant of the LF component of arterial pressure and R-R interval variability (0.70 +/- 0.07 and 0.18 +/- 0.05, respectively). The effect of the LF component of MSNA on arterial pressure showed no change in response to propranolol but was diminished (0.35 +/- 0.08) by phentolamine (P < 0.02). The effect of the LF component of MSNA on R-R interval was not altered by pharmacological sympathetic nerve blockade. The HF component of MSNA did not influence other variables but was influenced by R-R interval, arterial pressure, and respiration. These findings indicate that the LF component of MSNA reflects autonomic oscillations, whereas the HF component is passive and influenced by other cardiovascular variables.

Adolescent↗
PubMed1998

Bilateral coronary artery fistulas with multiple sites of drainage.

A 49-year-old woman presented with bilateral coronary fistulas with multiple sites of drainage. She had been referred to hospital for evaluation of a cardiac murmur, and a coronary arteriogram revealed multiple coronary fistulas. One fistula originated from the proximal part of the left anterior descending coronary artery and connected to the main pulmonary artery. Three coronary artery fistulas arised from a conal branch of the right coronary artery and drained into the main pulmonary artery, the right atrium and the great cardiac vein. This is the first reported case of bilateral coronary fistulas with multiple sites of drainage.

Coronary Angiography↗
PubMed1998

Germinoma causing wallerian degeneration. Case report and review of the literature.

Germinomas occurring in the thalamus and basal ganglia sometimes cause atrophy of the cerebral hemisphere on the affected side. The authors present the case of a 12-year-old girl with a germinoma that developed in the basal frontal lobe and cerebral basal ganglia. Magnetic resonance imaging showed atrophy not only of the cerebrum but also of the brainstem. A T2-weighted image revealed an area of high intensity that proved to be wallerian degeneration extending from the corona radiata and internal capsule to the brainstem. The authors suggest that this pathological change may be involved in the development of the symptoms and hemiatrophy associated with germinomas in this region of the brain.

Brain Neoplasms↗
PubMed1998

Development of multispectral autoradiography with solid state detector.

Autoradiography is a useful imaging technique to understand biological function by using radio isotopes (RIs). However, conventional autoradiography using X-ray film or Imaging Plate can not easily image distributions of different RIs simultaneously. Each tracers describes each biological functions, therefore we constructed here a multispectral autoradiography. The system consists of a solid state detector (SSD) with high energy-resolution to acquire multispectral information, a collimator with small aperture to restrict the region of observing area, and a translational stage to scan the specimen. The distribution of the RI of interest agent can be obtained by mapping spectrum intensity within the energy-window to corresponding observed points. We confirmed the validity of this method by experiments with physical phantoms and tissues of rat's hearts. First, we imaged the phantom with 201Tl and 99mTc, and could specify the individual RIs. Next, from rectangular paper phantom soaked in 99mTc-labeled tracer, the spatial resolution of experimental system was estimated on about magnitude of x mm2. Finally, the sliced tissue of rat's heart was imaged. Here, we also propose a new imaging method to improve the spatial resolution and reduce data-acquisition time. It is based on reconstruction from projections like X-ray CT.

Animals↗
PubMed1998

[A case report of epidural abscess due to anaerobic bacteria, producing a mass of gas].

A 54-year-old female was admitted to our hospital on May 8, 1996, for evaluation of fever and headache. Her cerebrospinal fluid showed elevation of the cell count and total protein. The thoracic and lumbar MRIs revealed abnormal gas occupying the epidural space at the sacral level, and extended as high as 9th thoracic level. The gas spread inside the iliopsoas and paraspinal muscles. Anaerobic bacteria such as Bacteroides fragilis and Peptostreptococcus productus were cultured from the spinal fluid and Bacteroides was also detected from the epidural tissues obtained during laminectomy. The infectious source was decubitus extending around the sacral bone. The combination therapy of debridement with peroxide, catheter drainage of epidural abscess, intravenous and intrathecal antibiotics, and laminectomy presented her good outcome. This is a rare case of anaerobic bacterial spinal abscess, showing epidural and intramuscular gas as a prominent feature.

Abscess↗
PubMed1997

Estrogen inhibits bone resorption by directly inducing apoptosis of the bone-resorbing osteoclasts.

Estrogen deficiency causes bone loss, which can be prevented by estrogen replacement therapy. Using a recently developed technique for isolation of highly purified mammalian osteoclasts, we showed that 17 beta-estradiol (E2) was able to directly inhibit osteoclastic bone resorption. At concentrations effective for inhibiting bone resorption, E2 also directly induced osteoclast apoptosis in a dose- and time-dependent manner. ICI164,384 and tamoxifen, as pure and partial antagonists, respectively, completely or partially blocked the effect of E2 on both inhibition of osteoclastic bone resorption and induction of osteoclast apoptosis. These data suggest that the protective effects of estrogen against postmenopausal osteoporosis are mediated in part by the direct induction of apoptosis of the bone-resorbing osteoclasts by an estrogen receptor- mediated mechanism.

Animals↗
PubMed1997

Severe cutaneous and venous damage after DIC therapy.

A 79-year-old woman with skin ulcers caused by disseminated intravascular coagulation (DIC) therapy is reported. The patient had been treated by injection of drugs, including gabexate mesilate, into the right great saphenous vein. The maximum concentration of gabexate mesilate was calculated as 0.893%. Although the drugs did not extravasate, purpura initially appeared around the affected vein, followed by brown pigmentation with infiltration and ulcers with widely necrotic tissue from the middle portion of her thigh to the malleolus along her right great saphenous vein. As the ulcer showed no tendency to heal for more than 3 months, surgical debridement and skin grafts were performed.

Aged↗
PubMed1997

Osteoclasts are present in gp130-deficient mice.

Interleukin (IL)-6, IL-11, leukemia inhibitory factor, and oncostatin M similarly induce osteoclast formation in cocultures of osteoblastic cells and bone marrow cells. These cytokines share a common signal transducer, gp130, which forms a receptor complex with the specific receptor for each cytokine. To investigate the role of gp130 in osteoclast development, we examined bone tissues in gp130-deficient and wild-type newborn mice of the ICR background. Soft x-ray radiographs and microfocus x-ray computed tomographs revealed that bone marrow cavities were present in tibiae and radii of both wild-type and gp130-deficient mice. Microfocus x-ray computed tomography and histological examination demonstrated a decrease in the amount of trabeculae at the metaphysial region in tibiae and radii of the gp130-deficient mice compared with the wild-type mice. The number ofosteoclasts in gp130-deficient mice was about double that in the wild-type mice. There were no apparent differences in the distributions of alkaline phosphatase-positive osteoblasts and the osteoid surface on the trabecular bone at the metaphysial region between the wild-type and gp130-deficient mice. The volume of mineralized trabecular bones was also decreased at mandibulae, accompanied by the increased number of osteoclasts in gp130-deficient mice compared with the wild-type and heterozygous mice. These results suggest that the formation of osteoclasts is not solely dependent on gp130 signaling, at least during fetal development. The osteoclastic bone resorption in gp130-deficient mice may be caused by the functional redundancy of bone-resorbing hormones and cytokines other than those of the IL-6 family.

Animals↗
PubMed1997

Down-regulation of gap junctional intercellular communication between osteoblastic MC3T3-E1 cells by basic fibroblast growth factor and a phorbol ester (12-O-tetradecanoylphorbol-13-acetate).

To address the relation between osteoblast growth and cell-to-cell communication, we examined the effects of basic fibroblast growth factor (bFGF) and 12-O-tetradecanoylphorbol-13-acetate (TPA), both potent stimulators of osteoblastic proliferation, on gap junctional intercellular communication between osteoblastic MC3T3-E1 cells. The level of intercellular communication was estimated by a photobleaching method. TPA inhibited the degree of intercellular communication in two different time-dependent manners. The early (< 1 h) inhibition by TPA was consistent with an increase in the phosphorylation of connexin 43 (Cx43). The later inhibition was caused by reduction in the total amount of Cx43 on the plasma membrane, due to the decrease in the level of Cx43 transcripts. These qualitative and quantitative modulations by TPA were inhibited by a selective inhibitor of protein kinase C, GF109203X. bFGF also attenuated the gap junctional intercellular communication. However, short exposure (< 5 h) to bFGF did not affect the communication. The fact that the growth factor immediately stimulated the phosphorylation of Cx43 indicates that the phosphorylation site(s) affected by bFGF was not involved in the inhibition of communication. The decrease in the intercellular communication level was detected by the longer exposure (> 8 h) to bFGF and paralleled the decline in the Cx-mRNA level. This inhibitory effect of bFGF was abolished by the addition of a tyrosine kinase inhibitor, herbimycin A. Thus, gap junctional intercellular communication between osteoblasts was down-regulated by osteoblastic mitogens through different mechanisms of the modulation of Cx43.

3T3 Cells↗
PubMed1997

[Progress of the therapy for virus related neurological disorders].

In this review of the therapy of infectious diseases and immune mediated nervous system diseases, we summarized the latest reports of antiviral drugs, immunosuppressants, immuno-modulatory and anti-inflammatory agents. Those include, acyclovir, vidarabine for herpes simplex encephalitis, ganciclovir for cytomegaro virus infection, inosine pranobex for SSPE, steroid therapy, interferon, plasma exchange and high-dose intravenous gamma globulin therapy for HTLV-I associated myelopathy, and multiple sclerosis. Diagnostic application of the PCR and the newly developed neuroimaging techniques, like diffusion weighted MRI, high speed MRI, and SPECT, we now being introduced to enable early recognition of viral infection of the CNS. And since speed of spread of HIV infection through the world, we are needed specific treatment for HIV infection, and various studies including genetic therapy is going on today.

Humans↗
PubMed1997

[The inhibitory effects of Arg-Gly-Asp-Ser on attachment of fibroblasts].

Trabeculectomy often fails because of scarring of the filtering bleb, which is caused by the proliferation of fibroblasts. In this study, we investigated the inhibitory effect of Arg-Gly-Asp-Ser (RGDS) oligopeptide, a cell binding domain of fibronection molecules, on the attachment of fibroblasts in vitro and on scarring of filtering bleb after trabeculectomy on rabbits' eyes. The following results were obtained. 1. RGDS inhibited the attachment of rabbit conjunctival fibroblasts significantly (p < 0.01) when it was added to the culture medium at final concentrations of 2 and 5 mg/ml. 2. The administration of 0.2 ml of RGDS solution (5 mg/ml) into the filtering bleb 3 days after surgery caused significant reductions of intra ocular pressure compared with the control maintained the bleb more than 13 days whereas the blebs of the control eyes disappeared within 6 days (p < 0.01). 3. No complications were caused on the eyeballs of the rabbits by the administration of RGDS.

Animals↗
PubMed1997

Pharmacological profile of the novel antidepressant 4-(2-fluorophenyl)-6-methyl-2-(1-piperazinyl)thieno-[2,3-d]pyrimidine monohydrate hydrochloride.

This is a first report on the investigation of the antidepressant activity of MCI-225 (4-(2-fluorophenyl)-6-methyl-2-(1-piperazinyl)thieno[2,3-d]pyrimidine monohydrate hydrochloride, CAS 99487-26-0) in comparison with maprotiline (CAS 10347-81-6), desipramine (CAS 58-28-6), imipramine (CAS 113-52-0) and trazodone (CAS 25332-39-2). MCI-225 inhibited the synaptosomal uptake of noradrenaline (NA, Ki = 35.0 nmol/l), serotonin (5-HT, Ki = 491 nmol/l), and dopamine (Ki = 14,800 nmol/l), although it did not inhibit MAO-A and MAO-B activities. MCI-225 showed high affinity only for the 5-HT3 receptor (Ki = 81.0 nmol/l) among all receptors tested including M1, M2, alpha 1, and H1 receptors. The inhibition of the von Bezold-Jarisch reflex by MCI-225 (ID50 = 22.2 mg/kg, p.o.) suggests its antagonistic action on the 5-HT3 receptor. MCI-225 dose-dependently reduced reserpine-induced hypothermia (0.3-10 mg/kg, p.o.) and potentiated yohimbine-induced lethality (3-100 mg/kg, p.o.) in mice. These effects of MCI-225 were as potent as desipramine and more potent than maprotiline, imipramine and trazodone. MCI-225 and desipramine did not change either 5-HTP-induced head movements or p-CA-induced hyperactivity in rats. In forced swimming tests in rats, the minimum effective doses of MCI-225, maprotiline, desipramine, and imipramine were 1, 30, 10 and 30 mg/kg, p.o., respectively, for 5-days administration. Only MCI-225 had shown its full activity with this short term treatment. MCI-225 (10 mg/kg, p.o.) decreased the REM sleep period without affecting slow-wave sleep or wakefulness in rats. Even at 100 mg/kg, p.o. MCI-225 and trazodone did not inhibit oxotremorine-induced tremor, lacrimation or salivation in mice in contrast with imipramine. These results suggest that MCI-225, which selectively inhibits NA uptake and antagonizes the 5-HT3 receptor, has potential as a new type of potent antidepressant.

Animals↗
PubMed1996

Mammalian mature osteoclasts as estrogen target cells.

The decrease in estrogen levels that follows the onset of menopause causes rapid bone loss, resulting in osteoporosis. However, the mechanism by which this occurs remains unclear, especially concerning the regulation of osteoclasts, i.e. the bone-resorbing cells. Using a pit assay involving isolated mature osteoclasts from rabbit long bones, we found that estrogen inhibited the bone-resorbing activity in a dose- and time-dependent manner. Furthermore, we clarified by Northern analysis that estrogen down-regulated the mRNA levels of cathepsin K/OC-2 and that putative estrogen receptor (ER) mRNA was expressed in these osteoclasts. Moreover, other sizes of mRNAs that hybridized with ER cDNA probe were found in these cells. Our results suggest that osteoclasts may be indeed target cells for estrogen and that estrogen might regulate a part of bone metabolism through osteoclasts.

Animals↗