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Biomedical subjects

K Fukushima

Publications and source records attributed to K Fukushima.

At least 109 records · Page 6Linked to original sources
PubMed2000

Effects of cardiac sympathetic innervation on regional wall motion abnormality in patients with long QT syndrome.

AIM: To assess the spatial relation between regional cardiac sympathetic innervation and regional ventricular repolarisation indicated by ventricular wall motion abnormality in patients with congenital long QT syndrome. DESIGN: Regional percentage uptake and washout rate of (123)I metaiodobenzylguanidine (MIBG) were measured to assess cardiac sympathetic innervation in septum, anterior wall, lateral wall, and posterior wall. Left ventricular short axis images on echocardiography were digitised to reconstruct digitised M mode echocardiograms, from which left ventricular wall thickness curves were obtained. The wall thickening time (ThT) was defined as the period in which the instantaneous wall thickness exceeded 90% of the maximum wall thickness. The ThT was measured from the ventricular wall thickness curve at the same segments where regional percentage uptake and washout rate of (123)I MIBG were measured. PATIENTS: Seven patients with long QT syndrome. RESULTS: The regional washout rate (mean (SD)) of (123)I MIBG in patients with long QT syndrome was greater in the segments with decreased percentage uptake of (123)I MIBG than in those without (17.4 (10.6)% v 9.7 (16.5)%, p < 0. 03). ThT in segments both with and without decreased percentage uptake of (123)I MIBG was longer than in control subjects (p < 0. 0001). ThT was longer in the segments with decreased percentage uptake of (123)I MIBG than in those without (199 (70) ms v 150 (66) ms, p = 0.0018). CONCLUSIONS: Activation of regional cardiac sympathetic terminals is likely to participate in additional regional prolongation of ventricular repolarisation in patients with long QT syndrome.

3-Iodobenzylguanidine↗
PubMed2000

Identification of genes involved in mucosal defense and inflammation associated with normal enteric bacteria.

Normal luminal bacteria and their products play a role in experimental colitis and inflammatory bowel disease. However, what molecules from what cells are responsible for mounting and maintaining the mucosal defense against luminal flora is still uncertain. The aim of this study was to identify epithelial gene products involved in mucosal defense and inflammation associated with ubiquitous enteric bacteria. Germ-free ICR mice were given an oral bacterial suspension prepared from conventional components (bacterial reconstitution). Small intestinal and colonic epithelial cells were isolated from bacteria-reconstituted, germ-free, and specific pathogen-free mice. Differential gene expression was investigated by differential display, Northern blot, and sequence analysis. Bacterial reconstitution resulted in acute but self-limited colitis. In epithelial cells, we observed the induction of small intestine-specific genes of the cryptdin family and colon-specific expression of serum amyloid A1 gene. This novel approach allows the identification of known and novel gene products involved in mucosal defense against luminal microorganisms and the associated inflammatory response.

Animals↗
PubMed2000

Activity of smooth pursuit-related neurons in the monkey periarcuate cortex during pursuit and passive whole-body rotation.

Smooth pursuit and vestibularly induced eye movements interact to maintain the accuracy of eye movements in space (i.e., gaze). To understand the role played by the frontal eye fields in pursuit-vestibular interactions, we examined activity of 110 neurons in the periarcuate areas of head-stabilized Japanese monkeys during pursuit eye movements and passive whole-body rotation. The majority (92%) responded with the peak of their modulation near peak stimulus velocity during suppression of the vestibuloocular reflex (VOR) when the monkeys tracked a target that moved with the same amplitude and phase and in the same plane as the chair. We classified pursuit-related neurons (n = 100) as gaze- velocity if their peak modulation occurred for eye (pursuit) and head (VOR suppression) movements in the same direction; the amplitude of modulation during one less than twice that of the other; and modulation was lower during target-stationary-in-space condition (VOR x1) than during VOR suppression. In addition, we examined responses during VOR enhancement (x2) in which the target moved with equal amplitude as, but opposite direction to, the chair. Gaze-velocity neurons responded maximally for opposite directions during VOR x2 and suppression. Based on these criteria, the majority of pursuit-related neurons (66%) were classified as gaze-velocity with preferred directions uniformly distributed. Because the majority of the remaining cells (32/34) also responded during VOR suppression, they were classified as eye/head-velocity neurons. Thirteen preferred pursuit and VOR suppression in the same direction; 13 in the opposite direction, and 6 showed biphasic modulation during VOR suppression. Eye- and gaze-velocity sensitivity of the two groups of cells were similar; mean (+/- SD) was 0.53 +/- 0.30 and 0.50 +/- 0.44 spikes/s per degrees /s, respectively. Gaze-velocity (but not eye/head-velocity) neurons showed significant correlation between eye- and gaze-velocity sensitivity, and both groups maintained their responses when the tracking target was extinguished briefly. The majority of pursuit-related neurons (28/43 = about 65%) responded to chair rotation in complete darkness. When the monkeys fixated a stationary target, more than half of cells tested (21/40) discharged in proportion to the velocity of retinal motion of a second laser spot (mean velocity sensitivity = 0.20 +/- 0.16 spikes/s per degrees /s). Preferred directions of individual cells to the second spot were similar to those during pursuit. Visual responses to the second spot movement were maintained even when it was extinguished briefly. These results indicate that both retinal image- and gaze-velocity signals are carried by single periarcuate pursuit-related neurons, suggesting that these signals can provide target-velocity-in-space and gaze-velocity commands during pursuit-vestibular interactions.

Animals↗
PubMed2000

Expression of Lewis(a), sialyl Lewis(a), Lewis(x) and sialyl Lewis(x) antigens as prognostic factors in patients with colorectal cancer.

BACKGROUND: Altered expression of blood group-related carbohydrate antigens such as sialyl Lewis (Le)(x) antigen in tumours is associated with tumour progression behaviour and subsequent prognosis. However, the prognostic value of the expression of Le-related antigens in colorectal tumours remains unclear. PURPOSE: To clarify the prognostic value of Le(a), sialyl Le(a), Le(x) and sialyl Le(x) expression in colorectal carcinomas as prognostic factors after surgery. PATIENTS AND METHODS: Colorectal carcinoma samples from 101 patients with primary colorectal carcinoma who underwent surgical resection were subject to immunohistochemical analyses for Lea, sialyl Lea, Lex and sialyl Le(x) expression with the respective monoclonal antibodies. RESULTS: Le(a), sialyl Le(a), Le(x) and sialyl Le(x) were expressed in 69 (68.3%), 73 (72.3%), 66 (65.4%) and 76 (75.3%) carcinomas, respectively. The patients with sialyl Lex-expressing tumours had more advanced cancer than those with nonsialyl Lex-expressing tumours (P=0.0029). The survival time after surgery of patients with Le(x)- or sialyl Le(x)-expressing tumours was significantly shorter than the survival time of those with non-Le(x)- or nonsialyl Le(x)-expressing tumours, respectively (P=0.023 and P=0. 0001, respectively). Cox's regression analysis revealed that Le(x) and sialyl Le(x) expression, separate from stage and histological type, were prognostic variables for patient survival (hazard ratio [HR] for sialyl Le(x)-positive expression to sialyl L(x)-negative expression 2.90; HR for Le(x)-positive expression to Le(x)-negative expression 12.76 in stage I/IV, 0.63 in stage II and 1.69 in stage III). CONCLUSIONS: Le(x) expression and sialyl Le(x) expression in colorectal carcinomas are each associated with poor prognosis. These variables should be considered in the design of future trials.

Colorectal Neoplasms↗
PubMed2000

Butyric-acid-induced apoptosis in murine thymocytes and splenic T- and B-cells occurs in the absence of p53.

Butyric acid, an extracellular metabolite from periodontopathic bacteria, induces apoptosis in murine thymocytes, splenic T-cells, and human Jurkat T-cells. The present study examines the contributions of apoptosis-related proteins (Bcl-2, Bcl-XL, Bax, and p21WAF1/CIP1) in the regulation of T-cell death induced by butyric acid, using p53 knock-out (p53-/-) and wild-type (p53+/+) mice. The results of a DNA fragmentation assay indicated that thymocytes, splenic T-cells, and B-cells from p53-/- mice were susceptible to butyric-acid-induced apoptosis to a degree similar to those from p53+/+ mice. Moreover, butyric acid significantly induced apoptosis in lymphocytes from both p53+/+ and p53-/- mice in a concentration- and time-dependent fashion. Experiments with fractionated subpopulations of splenic T-cells revealed that DNA fragmentation was equally observed in CD4+ and CD8+ splenic T-cells from both p53+/+ and p53-/- lymphocytes. Activation of caspase-3, caspase-6, and caspase-8, but not of caspase-1, in butyric-acid-induced T-cell apoptosis occurred regardless of the presence of p53. Western blotting analysis of splenic T-cells showed that butyric acid treatment decreased Bcl-2 and Bcl-XL expressions in p53+/+ and p53-/- cells. Splenic T-cells had barely detectable Bax and p21WAF1/CIP1, regardless of whether butyric acid and/or p53 was present. These results suggest that butyric-acid-mediated apoptosis of murine T-cells takes place via a pathway that is independent of p53, and is followed by the p53-regulated proteins Bax and p21WAF1/CIP1, which lower the levels of the apoptosis antagonists Bcl-2 and Bcl-XL in cells.

Animals↗
PubMed2000

Interleukin 5 and granulocyte-macrophage colony-stimulating factor levels in bronchoalveolar lavage fluid in interstitial lung disease.

The purpose of this study was to evaluate the role of several eosinophil growth factors including interleukin (IL)-5, interleukin (IL)-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) in the pathogenesis of interstitial lung disease with eosinophilia. IL-5, IL-3 and GM-CSF in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay (ELISA) in patients with eosinophilic pneumonia (EP), bronchiolitis obliterans organizing pneumonia (BOOP), idiopathic pulmonary fibrosis (IPF), sarcoidosis and healthy volunteers. IL-5 in BALF was high only in patients with EP. IL-3 in BALF was undetectable in the majority of patients with these diseases. GM-CSF in BALF was detectable in 30-67% of each group of patients. In patients with BOOP and IPF, the number of eosinophils in BALF was higher in patients with detectable GM-CSF than in patients in whom GM-CSF was below the detection limit. Eosinophil cationic protein (ECP) was detected in all patients with EP and some with BOOP and IPF. There was a significant correlation between ECP levels and percentage or number of eosinophils in BALF. The results suggest the possibility that interleukin 5 in eosinophilic pneumonia, and granulocyte-macrophage colony-stimulating factor in bronchiolitis obliterans organizing pneumonia and idiopathic pulmonary fibrosis may play important roles in eosinophil recruitment in the lung. Activation of eosinophils in the lung is likely to be induced by both interleukin 5 and granulocyte-macrophage colony-stimulating factor.

Adult↗
PubMed2000

11Beta-hydroxysteroid dehydrogenase type II and mineralocorticoid receptor in human placenta.

In mineralocorticoid target organs, 11beta-hydroxysteroid dehydrogenase type II (11beta-HSD2) confers specificity on the mineralocorticoid receptor (MR) by converting biologically active glucocorticoids to inactive metabolites. Placental 11beta-HSD2 is also thought to protect the fetus from high levels of circulating maternal glucocorticoid. In this study, we examined the immunoreactivity of 11beta-HSD2 and MR in human placenta from 5 weeks gestation to full term using immunohistochemistry, 11beta-HSD2 messenger RNA (mRNA) expression using Northern blot analysis, and MR mRNA expression using RT-PCR analysis. Marked 11beta-HSD2 immunoreactivity was detected in placental syncytiotrophoblasts at all gestational stages. MR immunoreactivity was moderately detected in syncytiotrophoblasts, some cytotrophoblasts, and interstitial cells of the villous core. Marked mRNA expression of 11beta-HSD2 was detected in placenta by Northern analysis. RT-PCR analysis of MR in placental tissues showed an amplified product consistent in length with the primers selected. These results suggest that placental 11beta-HSD2 is involved in not only regulating the passage of maternal active glucocorticoids into the fetal circulation but also in regulation of maternal-fetal electrolyte and water transport in the placenta, as in other mineralocorticoid target organs.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed2000

A new pentanorlanostane derivative, cladosporide A, as a characteristic antifungal agent against Aspergillus fumigatus, isolated from Cladosporium sp.

In the course of searching for new antifungal agents, a new pentanorlanostane derivative, cladosporide A (1), was isolated along with ergosterol, ergosterol peroxide and 23,24,25,26,27-pentanorlanost-8-ene-3beta,22-diol (2) from Cladosporium sp. as a characteristic antifungal agent against the human pathogenic filamentous fungus Aspergillus fumigatus. The structure of 1 was established as 3beta,22-dihydroxy-23,24,25,26,27-pentanorlanostane-29-al by spectroscopic and chemical investigation and X-ray crystallographic analysis. Inhibitory activity against A. fumigatus (IC80 0.5-4.0 microg/ml) was observed for cladosporide A (1), but no activity was observed against pathogenic yeasts, Candida albicans and Cryptococcus neoformans, and other pathogenic filamentous fungi, Aspergillus niger and A. flavus. The 4beta-aldehyde residue in 1 might be essential for the antifungal activity, since 23,24,25,26,27-pentanorlanost-8-ene-3beta,22-diol (2) showed no inhibition against the above four fungi.

Antifungal Agents↗
PubMed2000

Isolation of Candida dubliniensis from the oral cavity of an HIV-positive child in Brazil.

Candida dubliniensis is a newly-recognized Candida species and an important infectious pathogen, particularly for HIV-positive patients. >From oral smear samples from the radix linguae of 173 HIV-positive children, we obtained four yeast isolates which took a blue-green color on CHROMagar Candida plate at 37 degrees C for 48 hours from one HIV-positive 3-year-old boy in Brazil. The isolates were difficult to grow on potato dextrose agar plate at 42 degrees C, produced abundant chlamydospores on a cornmeal agar plate with Tween 80, and sprouted germ tubes in saline with horse serum, and the antigenic profile by CANDIDA CHECK test was useless. Carbohydrate assimilation tests by ID32C showed no reference code number in the reference book. The isolates were subjected to molecular biological assay of the DNA sequence of the large-subunit ribosomal DNA region (D1/D2) and randomly amplified polymorphic DNA (RAPD). The DNA sequence agreed with those of standard C. dubliniensis strains, and therefore, the isolates were identified as C. dubliniensis. RAPD band pattern analysis indicated that the clinical isolates might summarize one genotype. Although the child did not present oral lesions, the fungus might be latent for opportunistic infection.

Brazil↗
PubMed2000

[Simple evaluation of CT findings in the paranasal sinuses for chronic sinusitis].

The CT scores and scoring for improvement based on them, which we proposed previously, is a simple and highly reproducible method of evaluation of sinus units before and after an operation for chronic sinusitis. We compared this evaluation method with the results of quantitative assay and showed its advantages and disadvantages. The subjects were 258 sinuses in patients who underwent endonasal sinus surgery (ESS) in the department of otolaryngology, Kyoto Prefectural University of Medicine Hospital from April 1996 to April 1997. The subjects were evaluated according to the following 4 grades negligible shadow in the paranasal sinus CT scored 0, less than 50% shadow scored 1, more than 50% of shadow scored 2, and mostly filled with shadow scored 3. Furthermore, the preoperative and postoperative CT scores were compared and the rate of improvement was rated in the following 3 grades: score 0 for unchanged or aggravated subjects, score 1 for subjects showing improved CT score by 1 grade, and score 2 for those showing improved CT score by 2 grades or a postoperative CT score of 0. Quantitative image analysis was input into a personal computer and the ratio occupied by the shadow was calculated, as the shadow ratio. While some discrepancies were seen in parts in the comparison of the quantitative image analysis and CT scores as the former captures minute shadows, a positive correlation was obtained overall. Attention is needed to accurately evaluate small paranasal sinuses such as the frontal sinus, and small amounts of shadow, which are areas where errors may occur. A satisfactory correlation was obtained between the score for the improvement rate and the difference in the shadow ratios before and after surgery. The CT scores and the scores for the improvement rate showed no difference from the results of other evaluation methods reported in the past, and evaluation of similar precision was possible. It was thought that this simple evaluation method of CT findings in the paranasal sinuses, which we examined in the present study, was quite useful as a simple stage-classification method that could be utilized in everyday practice considering its facility, reproducibility and satisfactory precision.

Adult↗
PubMed2000

Cross axis VOR induced by pursuit training in monkeys: further properties of adaptive responses.

We have shown recently in alert monkeys that repeated interaction between the pursuit and vestibular systems in the orthogonal plane induces adaptive changes in the VOR. To examine further properties of adaptive cross axis VOR induced by pursuit training, sinusoidal whole body rotation was applied either in the pitch or yaw plane while presenting a target spot that moved orthogonally to the rotation plane with either 90 degrees phase-lead or 90 degrees phase-lag to the chair signal. After one hour of training at 0.5 Hz (+/- 10 degrees), considerable phase-shift was observed in orthogonal eye movement responses consistent with the training paradigms by identical chair rotation in complete darkness, with further lead at lower frequencies and lag at higher frequencies. However, gains (eye/chair) induced by phase- shift pursuit training was different during pitch and yaw rotation. Although frequency tuning was maintained during pitch in the phase-shift paradigms, it was not maintained during yaw, resulting in higher gains at lower stimulus frequencies compared to the gains during yaw. This difference may reflect otolith contribution during pitch rotation. To understand further the nature of signals that induce adaptive cross axis VOR, we examined interaction of pursuit, whole field-visual pattern and vestibular stimuli. Magnitudes of the cross axis VOR with a spot alone on one hand and with a spot and pattern moving together in the same plane on the other during chair rotation were similar, and when one of the two visual stimuli was stationary during chair rotation, our well trained monkeys did not induce the cross axis VOR. These results suggest that the cross axis VOR induced by pursuit training shares common mechanisms with the cross axis VOR induced by whole field-slip stimuli and that if conflicting information is given between the two visual stimuli, adaptive changes are inhibited. Horizontal GVPs were recorded in the cerebellar floccular lobe during pitch rotation coupled with horizontal pursuit stimuli. These GVPs did not respond to pitch in the dark before training, but responded after 60 min of pursuit training with eye velocity sensitivities similar to those before training. Adaptive change in the VOR was specific to smooth eye movements but not to saccades in our paradigms.

Adaptation, Physiological↗
PubMed2000

Brain fluorine-18 fluorodeoxyglucose imaging with dual-head coincidence gamma camera: comparison with dedicated ring-detector positron emission tomography.

BACKGROUND AND PURPOSE: Dual-head coincidence gamma camera (DHC) imaging has been proposed as an alternative to dedicated ring-detector positron emission tomography (dr-PET) for clinical fluorodeoxyglucose (FDG) studies. The purpose of this investigation was to assess the quality of DHC images in FDG studies of the human brain. METHODS: Seven healthy volunteers and 12 patients with various cerebral disorders underwent consecutive brain dr-PET and DHC with FDG. All sets of images were compared semiquantitatively using regions of interest. RESULTS: Cortical count ratios to the cerebellum on DHC and dr-PET images did not differ significantly among the volunteers, except in the superior frontal cortex and thalamus. In all studies including those of cerebral disorders, the mean cortical-to-cerebellar ratios of DHC and dr-PET images correlated closely. CONCLUSION: FDG imaging with DHC delineated the metabolic distribution of glucose in the brain as well as dr-PET did, except in the superior frontal cortex and thalamus. Therefore, DHC may be a dedicated cost-effective means of detecting metabolic abnormalities in the brain.

Adult↗
PubMed2000

Attenuation correction for cardiac dual-head gamma camera coincidence imaging using segmented myocardial perfusion SPECT.

UNLABELLED: The diagnostic accuracy of cardiac FDG imaging obtained with the dual-head coincidence gamma camera (DHC) is impaired by artifacts induced by nonuniform attenuation. This study proposed a new method (registration and segmentation method for attenuation correction [AC-RS]) to correct these attenuations in the chest region without the need for additional hardware or expensive transmission scanning equipment. METHODS: Before DHC imaging, 99mTc-tetrofosmin SPECT was performed using dual-energy acquisition from both the photopeak and Compton scatter windows. The scatter window images of the 99mTc-tetrofosmin were then registered 3-dimensionally with the cardiac DHC images and segmented into anatomic regions to obtain body and lung contours by applying the optimal threshold method on localized histograms. Theoretic attenuation coefficient values were assigned to the corresponding anatomic regions, and the DHC emission images were reconstructed using these attenuation correction factors. The results were quantitatively evaluated by imaging a cardiac phantom filled with a uniform solution and placed in a chest phantom. Eight nondiabetic subjects were also examined using this technique, and the results were compared with those of measured attenuation-corrected PET images. RESULTS: Use of this technique in phantom and clinical studies decreased the degree of artifacts seen in the inferior wall activity and corrected the emission images. When the results were compared with those of PET scans, the regional relative counts of the uncorrected DHC scan did not correlate with the results of the PET scan. However, the regional relative counts of the AC-RS-corrected DHC scan exhibited a linear correlation with the results of the PET scan (r = 0.73; P < 0.001). CONCLUSION: Reasonably accurate attenuation-corrected cardiac DHC images can be obtained using AC-RS without the need for transmission scanning.

Aged↗
PubMed2000

Estimation of myocardial perfusion and viability using simultaneous 99mTc-tetrofosmin--FDG collimated SPECT.

UNLABELLED: This study was designed to elucidate the usefulness of crosstalk correction for dual-isotope simultaneous acquisition (DISA) with 99mTc-tetrofosmin and FDG in estimating myocardial perfusion and viability. METHODS: Eighteen patients with coronary artery disease were studied. First, SPECT was performed with a low-energy high-resolution collimator after a single injection of 99mTc-tetrofosmin (single 99mTc-tetrofosmin). Second, PET and DISA with an ultra-high-energy collimator were performed after glucose loading and an injection of FDG. DISA was designed to operate with simultaneous 3-channel acquisition, and weighted scatter correction of crosstalk from the 18F photopeak to the 99mTc photopeak was performed by modification of an existing dual-window technique. The FDG SPECT images were compared with the images obtained by PET. Both crosstalk-corrected and uncorrected 99mTc-tetrofosmin images were generated and compared with the single 99mTc-tetrofosmin images. RESULTS: Regional percentage uptake of FDG agreed well between DISA and PET. However, regional percentage uptake of 99mTc-tetrofosmin was generally higher on the uncorrected 99mTc-tetrofosmin images than on the single 99mTc-tetrofosmin images, especially in areas of low flow (percentage count of 99mTc-tetrofosmin > or = 50%). The crosstalk correction contributed to improving the agreement between regional percentage uptakes and significantly improved the detectability of myocardial perfusion-metabolism mismatching. CONCLUSION: With 3-channel acquisition and weighted-scatter correction of crosstalk from the 18F photopeak to the 99mTc photopeak, DISA with 99mTc-tetrofosmin and FDG is feasible for assessing regional myocardial perfusion and viability.

Aged↗