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Biomedical subjects

K Imamura

Publications and source records attributed to K Imamura.

At least 163 records · Page 9Linked to original sources
PubMed1993

[Discarding medical images and its evaluation].

Following a survey of our filing system, the period of storage of medical images was generally limited to ten years, a system which was put into execution in 1990. Film jackets older than ten years are discarded every year, except for those registered for permanent storage. Fourteen thousand jackets (6.5% of total) have been registered for permanent storage. A follow-up survey has been performed to evaluate this system. The survey focused mainly on the frequency of re-issue of film jackets, and the rate of access to jackets. Discarded jackets now number about 50,000, a reduction of 20%. A total of 405 jackets were re-issued in a year due to the re-examination of patients whose jackets had been discarded. The annual number of re-called jackets from the repository outside our hospital was about 2,200 (about 500 of them were for research work), which corresponded to 1.5% of the patients re-examined in the radiology department. The new filing system has been well integrated into the hospital daily routine. Information cost was calculated as a function of access rate to the stored information, and the concept of "cost-of-information" was proposed as a measure of cost analysis of an information system.

Costs and Cost Analysis↗
PubMed1993

Enhancing effects of irrelevant lymphocytes on adoptive transferred experimental allergic encephalomyelitis.

To help understand effector mechanisms in experimental allergic encephalomyelitis (EAE) we examined the effects of adding 'irrelevant' lymphocytes from non-EAE donors to major basic protein (MBP)-reactive lymphocytes in the adoptive transfer of EAE (Tr-EAE). The intravenous injection of tetanus toxoid-reactive lymphocytes (TT-cells) and phytohemagglutinin-stimulated lymphocytes on the same day or 2 days after intra-arterial injection of MBP-reactive lymphocytes enhanced the clinical and pathological expression of Tr-EAE. In lymphocyte trafficking studies there was significant accumulation of these injected TT-cells in the central nervous system during enhanced transfer of EAE. W3/25-positive cells were much more predominant in lesion of central nervous system when reinjected with TT cells along with MBP cells compared with lesions of rats injected with MBP cells alone. These findings suggest possible participation of lymphocytes other than MBP-reactive cells in the expression of EAE and provide a useful model to further explore effector mechanisms in the future.

Animals↗
PubMed1993

Gliotoxin-induced suppression of ocular dominance plasticity in kitten visual cortex.

We studied the role of astrocytes in the regulation of ocular dominance plasticity. A small quantity of 10 microM fluorocitrate (0.2 nmol in 20 microliters) was pressure-injected into the visual cortex of 7-9-week-old kittens (subcortical depth: 0-5 mm, 20 microliters/10 min). Immediately after injection, 1 eye contralateral to the injected cortex was closed for 3 days. Single-unit recordings revealed that the proportion of binocular cells was significantly higher in a region close (approximately 1 mm) to the fluorocitrate injection site than that in a remote region (> 4 mm) within the same hemisphere and that in the opposite hemisphere. The results suggest that reduction of glial functions by fluorocitrate retarded the usual process of shift in ocular dominance of visual cells following monocular deprivation.

Animals↗
PubMed1993

Bruceanols D, E, and F three new cytotoxic quassinoids from Brucea antidysenterica.

Three new quassinoids, bruceanols D [1], E [2], and F [3], were isolated from Brucea antidysenterica, and their structures were elucidated by spectral evidence and chemical transformation. All of these compounds exhibited cytotoxicity against five human tumor cell lines, malignant melanoma (RPMI-7951), lung carcinoma (A-549), ileocecal adenocarcinoma (HCT-8), epidermoid carcinoma of the nasopharynx (KB), and medulloblastoma (TE-671), and against murine lymphocytic leukemia (P-388).

Animals↗
PubMed1993

Cytokine production by peripheral blood monocytes/macrophages in multiple sclerosis patients.

To determine the function of monocytes/macrophages in the acute phase of multiple sclerosis (MS), we investigated the production of tumor necrosis factor alpha (TNF alpha), interleukin-1 alpha (IL-1 alpha), IL-1 beta and IL-6 by peripheral blood monocytes/macrophages (PBM) in patients with MS, other autoimmune neurological disease (OAND), other neurological disease (OND) and normal controls was assessed using enzyme-linked immunosorbent assay (ELISA). When stimulated with lipopolysaccharide or phorbol ester, PBM obtained during acute phase of MS relapse patients produced significantly higher amounts of all these cytokines than did PBM from patients with chronic stable MS or OAND or OND or from normal controls. The results suggest a possible role of activated monocytes/macrophages in the acute exacerbation of MS.

Adult↗
PubMed1993

Denervated skeletal muscle: MR imaging. Work in progress.

PURPOSE: To evaluate the change in signal intensity of skeletal muscles after denervation and to determine the clinical usefulness of magnetic resonance (MR) imaging in diagnosis of denervation. MATERIALS AND METHODS: Denervated skeletal muscles associated with various forms of peripheral neuropathy and spinal radiculopathy were studied with MR imaging in 17 patients. RESULTS: On T1-weighted images, signal intensity of denervated muscles was normal in 14 patients and high in three. On T2-weighted images, all denervated muscles showed high signal intensity on at least one MR image. High signal intensity in the denervated muscles on T2-weighted images was observed 15 or more days after onset of paralysis. In two patients, signal intensity of denervated muscles returned to normal after relief of paralysis. CONCLUSION: MR imaging is a noninvasive and accurate method for use in diagnosis of denervation and may ultimately eliminate the need for electromyography.

Adipose Tissue↗
PubMed1993

Epidemiologic analyses of spatial clustering of bovine ephemeral fever outbreaks. I. Application of the negative binomial distribution.

An epidemic that propagates through a population results in a contagious spatial pattern. The incidence per farm of bovine ephemeral fever (BEF) outbreaks in the 22 areas of Fukuoka Prefecture in 1988 was well explained by the negative binomial distribution, which is generally considered, as the clustering of the outbreaks. Furthermore, the clustering was analyzed with three categories of vaccination rate (No. 1-40%, and 40-80%). As a result, the no vaccination and high vaccination rate (41-80%) groups tended to shift to similarly the Poisson distribution. It may be speculated that an insufficient vaccination control of the BEF was influenced with the clustering.

Animals↗
PubMed1993

A study on the values computed by dieticians and chemical analysis of fats, cholesterol, and P/S ratio in food.

Dieticians computed the fat and cholesterol contents of 11 foods that were commercially produced as ready-to-eat food from food component lists and obtained the P/S ratio (polysaturated/saturated fatty acids) from the fatty acid component list. Meanwhile the same foods were diluted and homogenized. The internal standard was combined with hepatadecanoic acid and tricaprin. The samples that had been extracted by the Folch method were analyzed for their lipid content (GC analysis using a HS-SS-10 columns for fatty acids and an OV-1 column for lipid and cholesterol). A significant positive correlation was noted between the results of dieticians' analysis and those obtained from a gas chromatographic analysis of lipid and cholesterol contents and the P/S ratio, proving that lipid analysis of food by dieticians is highly reliable. Therefore for diseases (such as hyperlipemia, arteriosclerosis, obesity, diabetes mellitus, fatty liver, and pancreatitis) in which dietary factors have a significant effect on their clinical course, dietary instructions on dietary fats based on an analysis by dieticians are considered to be effective.

Cholesterol↗
PubMed1993

Japan's experience in long-term home health care of the elderly.

Due to increasing national health expenditure and an aging society, Japan in the 1980s started to reinforce home health care, going beyond her long-time investment in institutional care. Since 1983, a sequence of policies was issued focused mainly on frail elderly care. In support of this governmental approach, a variety of enterprises and charity activities have flourished. Now, however, in the midst of a worldwide recession, rationing as health policy is under reconsideration and has an influence on health care for minorities, including the elderly. In Japan, home health care is under review and a new service system was initiated in April 1992. In this article, the newly inaugurated community-based home visiting nursing scheme is introduced together with a short history of elderly care and related business activities in Japan. Feasibility of the new scheme is discussed and compared with the previous version of home visiting nursing, which had its base in hospitals.

Aged↗
PubMed1993

[Etoposide/cis-platinum (CDDP) combined chemotherapy for ovarian cancer: evaluation of optimum schedule for CDDP administration in chronic continuous exposure of ovarian cancer cells to low-dose etoposide in vitro].

Combined chemotherapy with etoposide and cis-platinum (CDDP) is considered a second line regimen for refractory cases of ovarian cancer. In addition to the time-dependent cytocidal kinetic of etoposide, much attention has been paid to low-dose continuous administration of etoposide. In this study, ovarian cancer cells (SHIN-3) were continuously exposed to low-dose etoposide in vitro to determine the optimum schedule for CDDP administration. Etoposide concentrations of 1-3 micrograms/ml were used; per os administration of etoposide at 25 mg x 2/day has been shown to produce a continuous plasma concentration of etoposide of around 1 microgram/ml. The results were as follows: 1) The IC50 of CDDP after 72 hours of exposure was 8.0 micrograms/ml and that of etoposide after 114 hours was 3.0 micrograms/ml. 2) After 100 hours of exposure to 1 microgram/ml of etoposide, cell cyclic phase analysis showed cells predominantly in G2/M phase arrest. 3) After 24-hour administration of CDDP, it was more than 24 hours before a cytocidal effect was observed. 4) During continuous exposure of SHIN-3 to etoposide (1 microgram/ml) for 6 days, CDDP was added on the 1st, 3rd, and 5th days. The largest ratio of growth inhibition with combined treatment to that with CDDP alone was attained on the 5th day. We conclude that, in combination regimens using low-dose continuous etoposide, CDDP should be added after etoposide administration is begun.

Administration, Oral↗
PubMed1992

L-threo-3,4-dihydroxyphenylserine enhanced ocular dominance plasticity in adult cats.

We studied whether ocular dominance plasticity can be restored to the aplastic visual cortex of the adult cat by peripheral administration of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS), an exogenous precursor of L-noradrenaline (NA). We found that NA output in the visuocortical dialysate was significantly increased by a single administration of L-threo-DOPS (200 mg or 1 g, i.p.). Single unit recordings revealed a significant reduction of binocular cells (binocularity = 0.30) in juvenile cats (7-8 months of age) that had been monocularly deprived for one month in combination with L-threo-DOPS (200 mg/day, per os). These results suggest that peripheral administration of L-threo-DOPS enhances ocular dominance plasticity, presumably through activation of the central noradrenergic system.

Animals↗
PubMed1992

[Clinical application of 31P MRS to malignant liver tumors--with an emphasis on evaluation of response to therapy].

Malignant liver tumors in 19 cases (13 hepatomas and 6 metastatic tumors) were studied by 31P magnetic resonance (MR) spectroscopy. Five healthy volunteers were also studied. Volume localization was performed using the ISIS sequence. Compared with normal liver, the MR spectra of malignant tumors showed an elevated phosphomonoester (PME) peak relative to beta ATP (p less than 0.005), and tumors were slightly alkaline (pH 7.32 +/- 0.08) before therapy. Nine cases of hepatomas responding to chemoembolization showed extremely reduced signal intensity of spectra. Tumor pH was compared before and after therapy in four cases that showed good response to therapy, and was elevated in all of them. Three metastatic tumors with good response showed reductions in PME and ATP after therapy. MR spectroscopy with adequate localization technique is useful in demonstrating the response of malignant tumors to therapy.

Carcinoma, Hepatocellular↗
PubMed1992

Functional expression of the macrophage colony-stimulating factor receptor in human THP-1 monocytic leukemia cells.

Macrophage colony-stimulating factor (M-CSF) is required for the proliferation, differentiation, and activation of monocytes. High-affinity receptors for M-CSF are encoded by the c-fms proto-oncogene. In the present study, we show that c-fms transcripts are detectable in human THP-1 myeloid leukemia cells. Furthermore, radiolabeled 125I-M-CSF is rapidly internalized into THP-1 cells and then degraded intracellularly. The results also show that treatment of THP-1 cells with M-CSF is associated with the activation of protein kinase C (PKC) and the induction of tumor necrosis factor (TNF) gene expression. TNF transcript levels were low to undetectable in uninduced THP-1 cells, reached maximal levels by 1 hour of exposure to M-CSF, and returned to those of control cells by 24 hours. Transcriptional run-on analysis showed that a low level of TNF transcription is detectable in untreated THP-1 cells, and M-CSF treatment increased the rate of TNF transcription. Pretreatment of THP-1 cells with pertussis toxin inhibited the increase in PKC activity but not the induction of TNF transcripts by M-CSF. Moreover, exposure of THP-1 cells to inhibitors of protein kinase activity blocked the increase in TNF messenger RNA. These findings suggest that at least two M-CSF-mediated signaling pathways exist in THP-1 cells and that the induction of TNF may be regulated by a protein kinase-dependent mechanism distinct from PKC.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

[Signal contamination problem in three-dimensional localization technique of MR spectroscopy--experiment and an analysis of patient data].

Signal contamination from the surrounding volume was studied using the ISIS sequence, a three-dimensional localization technique. In phantom experiments, contamination decreased with the increase of Tr, regardless of where the contamination originated from. In 52 localized liver spectra with a Tr of 2 sec, PCr contamination was estimated at 3 to 4%, and contamination of ATP signals from the surrounding liver tissue at less than 1%, because of the relatively short T1 of ATP in the liver. In the spectra of brain neoplasms obtained using the simultaneous double-volume selection technique, the PCr ratio in the tumor relative to the control area was high in low grade astrocytoma (0.80, n =8) and low in others (0.45, n = 11). Considering contamination and spectral noise, a PCr ratio of less than 0.4 does not strongly suggest the existence of PCr in tumors. Among 25 cases whose therapeutic processes were monitored by MRS, signal disappearance was observed in two cases in the localized spectra after therapy. In both of them, tumor necrosis was proved pathologically and correlated well with spectroscopic findings. It was found that the ISIS technique suppressed signal contamination to the level of several percents, providing spectra of acceptable quality through localization.

Humans↗
PubMed1992

Changes of drebrin expression in the visual cortex of the cat during development.

The expression of and developmental changes in drebrin were studied in cat visual cortex using immunohistochemistry and immunoblot analysis. Drebrin is a developmentally regulated brain protein which in the chicken has characteristic changes in expression related to developmental stage. A monoclonal antibody (MAb M2F6) raised against drebrin, was found to label the neuropil of the kitten visual cortex in the early postnatal period. At 1-3 weeks of age, the staining was prominent in layer IV of the visual cortex. The immunoreactivity, however, was found to be dramatically decreased around the end of the sensitive period for ocular dominance plasticity (approximately 3 months of age). In the adult visual cortex, almost no immunostaining was observed. These developmental changes revealed by an immunohistochemical method were confirmed using immunoblot analysis. Upon immunoblot analysis after SDS-PAGE of protein from the kitten visual cortex, MAb M2F6 was found to recognize two protein bands with molecular weights of 130 kDa (drebrin E) and 140 kDa (drebrin A). The developmental profile of the intensity of the two bands of the drebin closely parallels in time the postnatal changes in cortical susceptibility to visual deprivation. These results indicate that the expression of drebrin in kitten visual cortex is restricted to the early postnatal period and suggest that it may play an important role in the experience-dependent modification of cortical circuitry during the sensitive period.

Aging↗
PubMed1992

User and manufacturer's requirements for IMAC standardization in Japan.

Many radiologists and radiological technologists understand that Picture Archiving and Communication Systems (PACS) are useful not only for image management but also for improving the quality of patient care. However, such systems have not yet been widely installed in hospitals. In order to determine why radiologists have not installed a PACS in their hospitals, we carried out a written survey of 400 Japanese hospitals asking them to describe the current image management activities, the problems inherent in PACS and the problems related to standardization. 216 hospitals responded, and the following suggestions were compiled concerning possible improvements to PACS. (1) PACS benefit needs to be improved with respect to patient care. (2) The cost of PACS should be reduced. (3) The system should be easier to operate and should save time. (4) Standardization is needed to allow simplified, cost-effective networking. We also carried out a written survey of 25 PACS and related equipment manufacturers asking them to describe the opinions inherent in current PACs and the problems related to standardization. Ten manufacturers responded, and the various suggestions were compiled concerning possible improvements to the PAC system.

Japan↗