Biomedical subjects

M Fukuda

Publications and source records attributed to M Fukuda.

At least 109 records · Page 6Linked to original sources

PubMed2001

Expression of cell adhesion molecule and albumin genes in primary culture of rat hepatocytes.

Changes in the expression of cell adhesion molecule and albumin genes were investigated in primary cultures of rat hepatocytes with and without poly- N-p -vinylbenzyl-D-lactonamide (PVLA) coating of the dishes. In PVLA-coated cultures, hepatocytes aggregated into spheroids and expressed liver cadherin and albumin mRNAs at higher levels. In uncoated cultures, hepatocytes revealed low levels of cadherin and albumin mRNAs, but higher levels of integrin alpha-1 mRNA. The changes in mRNA levels of liver cadherin and integrin alpha-1 coordinated well with those in spheroid and monolayer formation of hepatocytes, respectively. These results suggest that, in the PVLA-coated culture, hepatocytes expressed cadherin at higher levels to promote cell-cell adhesion and further maintain the differentiated function, such as albumin secretion, for prolonged times.

Albumins↗

PubMed2001

Phase I study of second-line chemotherapy with docetaxel and carboplatin in advanced non-small-cell lung cancer.

PURPOSE: Docetaxel and carboplatin have a broad spectrum of antitumor activity. We conducted a phase I study of docetaxel and carboplatin as second-line chemotherapy in previously treated non-small-cell lung cancer (NSCLC). This study aimed to determine the maximum tolerated dose (MTD) and the dose-limiting toxicities in this second-line combination chemotherapy. METHODS: Patients with advanced NSCLC were treated with escalating docetaxel doses in combination with a fixed-target area under the concentration-time curve (AUC) of 5 mg min/ml of carboplatin on day 1 of a 3-4-week cycle. The carboplatin dose was determined by multiplying the AUC by the clearance predicted using the Chatelut formula. The docetaxel dose was escalated from 40 mg/m2 to the MTD by 10 mg/m2 increments. RESULTS: A total of 16 patients previously treated with anticancer drugs were enrolled through three dose levels (40, 50 and 60 mg/m2 of docetaxel). All patients were assessable for toxicity and response. The MTD was docetaxel 60 mg/m2 with a carboplatin target AUC of 5 mg min/ml, and the dose-limiting toxicities in two of four patients were neutropenia and thrombocytopenia. Overall, neutropenia and thrombocytopenia of grade 3/4 occurred in eight patients (50%) and three patients (19%), respectively. Four patients (25%) and two patients (13%) experienced both grade 1 diarrhea and dermatitis, respectively. Allergic reactions, fluid retention, pneumonitis, neurotoxicity and mucositis were not observed. Of 16 patients, 5 showed an objective response (response rate 31%; 95% CI 14-56%). CONCLUSIONS: The combination of docetaxel and carboplatin is a feasible and well-tolerated second-line chemotherapy regimen in the treatment of NSCLC. Docetaxel 50 mg/m2 under the carboplatin target AUC of 5 mg x min/ml using the Chatelut formula was the recommended dose for phase II study.

Adult↗

PubMed2001

Viability of liver grafts from fasted donor rats: relationship to sinusoidal endothelial cell apoptosis.

Previous studies have shown that livers from fasted donors appear to tolerate long-term preservation better than livers from fed donors, but the mechanism is not clear. Some studies have shown that the apoptosis of sinusoidal endothelial cells (SEC) appeared to be a pivotal mechanism of ischemia/reperfusion injury in liver transplantation. The purpose of the present investigation was to evaluate the relation of SEC apoptosis to liver viability in rats after liver transplantation, comparing findings for fasted and fed donors. Wistar rats were used as donors and recipients. The fed group had access to solid feed and water ad libitum. The fasted group was allowed access only to water for 4 days prior to liver harvest. All rat livers were preserved with University of Wisconsin (UW) solution at 2 degrees C for 24 h. After preservation, the livers were orthotopically transplanted, and survival time was measured. Apoptosis was determined by in-situ staining for apoptotic cells, using a TdT-mediated dUTP-digoxigenin nick-end labeling (TUNEL) assay and electron microscope (EM) examination separately. The 14-day survival rates after 24-h preservation were 0% (0/11) for recipients of livers from fed donors and 91% (10/11) for recipients of livers from fasted donors. There was no significant difference in the numbers of TUNEL-positive SEC after 24-h preservation between the two groups. However, at 6 h after transplantation, the number of TUNEL-positive SEC was significantly higher in the fed group than in the fasted group. These results suggest that donor fasting decreases SEC apoptosis after reperfusion alone, and that this may be related to the protection of the liver graft from reperfusion injury.

Analysis of Variance↗

PubMed2001

Organized thrombus of the tricuspid valve mimicking valvular tumor.

We report on a case of organized thrombus of the tricuspid valve mimicking a valve tumor. Preoperative transesophageal echocardiography showed the mass to have originated from the septal leaflet of the tricuspid valve. A pouch of the tricuspid valve and a ventricular septal defect were observed perioperatively, with the mass attached to the septal leaflet. Histologic examination revealed the mass to be an organized thrombus without tumor components.

Adult↗

PubMed2001

Immunohistochemical localization of inducible nitric oxide synthase in synovial tissue of human temporomandibular joints with internal derangement.

The expression and distribution of inducible nitric oxide synthase (iNOS) was examined in 12 samples of human temporomandibular joint (TMJ) with internal derangement (ID) and four control specimens. In the diseased joints, strong or definite iNOS reactivity was expressed in synovial lining and endothelial cells; weaker activity was present in synovial fibroblasts. In contrast, although there was weak expression of iNOS in synovial fibroblasts and endothelial cells in the two control specimens, there was no iNOS staining in the synovial lining cell layers. This original report that iNOS is expressed in the synovial tissue of the temporomandibular joint indicates that nitric oxide is produced locally at least in the synovial lining in these joints when affected by internal derangement.

Adolescent↗

PubMed2001

Maternal serum triglyceride at 24--32 weeks' gestation and newborn weight in nondiabetic women with positive diabetic screens.

OBJECTIVE: To determine whether elevated midpregnancy maternal serum lipid levels predict newborn weight at term and the risk of large for gestational age (LGA) infants in women with positive diabetic screen but normal glucose tolerance test. METHODS: Japanese gravidas who had positive diabetic screens and normal 75-g oral glucose tolerance tests (GTT) at 24--32 weeks were enrolled. Subjects with complications, including diabetes, hypertension, or fetal anomalies were excluded, as were women with multifetal gestations. Fasting serum triglyceride, free fatty acids, and total cholesterol levels were measured at the time of GTT. We tested the association between maternal variables and birth weight by univariable analysis. We used multivariable analysis to test whether the association between fasting lipids and birth weight was independent of prepregnant maternal body mass index (BMI), maternal weight gain during pregnancy, and plasma glucose levels at GTT. We also used multiple logistic regression analysis to determine whether maternal hyperlipidemia, defined as more than the 75th percentile of each lipid, is a risk factor for having an LGA infant. RESULTS: We enrolled 146 subjects. Among measured maternal lipids, only triglyceride levels correlated with birth weight in univariable analysis (r = 0.22, P =.009). Birth weight also was correlated with prepregnant maternal BMI (r = 0.18, P =.04) and fasting plasma glucose levels (r = 0.17, P =.04). The association between maternal fasting triglyceride level and birth weight remained significant after adjusting for prepregnant BMI, maternal weight gain, fasting plasma glucose levels, fetal gender, and gestational age at birth (P =.01). Logistic regression analysis showed that fasting maternal hypertriglyceridemia (over 259 mg/dL) was the significant predictor of LGA infants, independent of prepregnant BMI, maternal weight gain, and maternal plasma glucose levels (odds ratio 11.6; 95% confidence interval 1.1, 122; P =.04). CONCLUSION: In women with positive diabetic screens but normal GTTs, fasting triglyceride levels at 24-32 weeks correlated positively with newborn weight at term, independent of maternal plasma glucose levels and obesity. Maternal fasting serum triglyceride levels in midpregnancy might be an independent predictor of fetal macrosomia in those women.

Adult↗

PubMed2001

Differences in DNA synthesis in vitro using isolated nuclei from regenerating livers of young and aged rats.

To detect changes in DNA synthesis during ageing, we compare DNA synthesis in the livers of young and aged rats. As an intermediate between an in vivo system using intact cells and an in vitro system using purified DNA polymerases, isolated nuclei were prepared and used as the machinery for DNA synthesis. The DNA synthesizing capacity of nuclei from regenerating liver was higher than that of nuclei from normal liver and these capacities from liver and regenerating liver were lower in nuclear preparations from aged rats. DNA synthesis using isolated nuclei was stimulated by ATP and the cytoplasmic preparation. The cytoplasmic preparation from regenerating rat liver was found to stimulate DNA synthesis more than the preparation from normal liver. The activity in regenerating liver from young rats was also greater than in that from aged rats. It is well known that DNA replication is inhibited by aphidicolin and DNA repair by ddTTP. We examined the effects of aphidicolin and ddTTP on DNA synthesis using the nuclear system. Surprisingly, the inhibition by aphidicolin was 30% of total DNA synthesis using the nuclear system from young rats. On the other hand, the inhibition by ddTTP was approximately 80%. We measured the sizes of the DNA synthesized in the presence of both inhibitors. DNA synthesis was allowed to proceed for 10 min using isolated nuclei from regenerating liver of young rats and the size of the DNA was determined by sucrose density gradient centrifugation analysis. DNA products appeared in two fractions. Following a chase of 50 min in the presence or absence of aphidicolin, the short DNA product grew larger in both cases, although the amount of DNA in the presence of aphidicolin was approximately 90% that in its absence. In the same experiment using nuclei from aged rats, the amount in the presence of aphidicolin was approximately 60% that in its absence. These results suggest that DNA polymerase beta is closely related to abnormal replication when DNA polymerases alpha and delta are inhibited and that the effect of cytosol on DNA synthesis, as well as the DNA synthetic capacity of isolated nuclei, becomes lower in regenerating rat liver during ageing.

Aging↗

PubMed2001

Crystal structures of substrate free and complex forms of reactivated BphC, an extradiol type ring-cleavage dioxygenase.

BphC derived from Pseudomonas sp. strain KKS102, an extradiol type catecholic dioxygenase, is a non-heam iron-containing enzyme, playing an important role in the degradation of biphenyl/PCB (Poly Chlorinated Biphenyls) in the microbe. Although we had earlier solved the crystal structure of KKS102 BphC, it was the inactive form with Fe(III) in the active site. In order to determine the active form structure, BphC was re-activated by anaerobic incubation with Fe(II) and ascorbate, and crystallized anaerobically. The crystal structures of activated BphC and its substrate complex (E x S complex) were determined at 2.0 A resolution under cryogenic condition. In addition, crystal structures of unactivated BphC in substrate free and complex forms were also re-determined. Comparison of activated and unactivated E x S complexes reveals that the orientation of the bound substrate in the active site is significantly different between the two. The structural comparison of the substrate free and complex forms of activated BphC show certain small conformational shifts around the active site upon substrate binding. As a result of the conformational shifts, His194, which has been suggested as the catalytic base, takes part in a weak hydrogen bond with hydroxyl group of the substrate.

Anaerobiosis↗

PubMed2001

Delayed induction of pigmented spots on UVB-irradiated hairless mice.

Human skin exposed to solar radiation for a long time subsequently develops pigmented spots, which are named solar lentigines. Since no animal model of this process is currently available, we attempted to induce similar spots in pigmented hairless mice. The mice were irradiated at 38 or 94 mJ/cm(2) three times/week for various periods of time (1-8 weeks) under an ultraviolet light source (Toshiba FL-SE; UVB). Skin pigmentation of irradiated mice was visually observed and skin color was determined with a colorimeter for 78 weeks. Uniform pigmentation was induced, but persisted only during exposure, disappearing completely within 2 weeks after cessation of exposure. At about 28 weeks after the first exposure, pigmented spots suddenly began to appear. These pigmented spots were less than 2 mm in diameter and light brown in color. The length of the latent period until appearance and the extent of development of these spots were dependent on the exposure period. Histological examination revealed increased numbers of active melanocytes and melanin granules in the affected epidermis. These pigmented spots closely resemble solar lentigines in humans, and the mice should be useful as an animal model of solar lentigines.

Animals↗

PubMed2001

Expression of granulocyte colony-stimulating factor and its receptor in epithelial skin tumors.

Granulocyte colony-stimulating factor receptors (G-CSFR) have been observed on the surface of not only hematopoietic cells but also several cancer cells. In the present study, we investigated the expression of G-CSFR or G-CSF in epithelial skin tumors by immunohistochemical staining. The assessments were defined by the percentage of G-CSFR or G-CSF positive cells and expressed as G-CSFR and G-CSF scores. The G-CSFR score in SCC (77.6+/-20.0%) was significantly higher than that in Bowen's disease (BD) (51.0+/-35.6%), actinic keratosis (AK) (49.3+/-34.6%) or normal skin (30.0+/-32.1%) (P=0.0004, P=0.0003, P<0.0001, respectively). The mean G-CSF score in SCC (56.7+/-27.4%) or in BD (44.1+/-31.4%) was higher than that in normal skin (24.9+/-25.8%) (P=0.0075, P<0.001, respectively). G-CSF expression in AK (29.8+/-31.2%) was lower than that in SCC (P=0.0037). There was significant positive correlation between the G-CSFR score and the G-CSF score (gamma=0.274, P=0.0107) in skin tumors. These findings suggested that the assessment of G-CSFR expression might be associated with carcinogenesis of skin tumors.

Aged↗

PubMed2001

Phase I study of irinotecan and cisplatin with concurrent split-course radiotherapy in unresectable and locally advanced non-small cell lung cancer.

We conducted a phase I study of irinotecan (CPT-11) and cisplatin with concurrent split-course radiotherapy in locally advanced stage III non-small cell lung cancer (NSCLC). This study aimed to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of this therapy. Two chemotherapy cycles of CPT-11 (days 1, 8 and 15) and cisplatin (day 1) were repeated with a 28-day interval. Radiotherapy of 2 Gy/day commenced on day 2 of each chemotherapy cycle, with 24 Gy and 36 Gy administered for the first and second cycle, respectively. 24 eligible patients were enrolled at five dose levels (CPT-11/cisplatin: 40/60, 50/60, 60/60, 60/70 and 60/80 mg/m(2)), and 23 patients were evaluated for toxicity and clinical outcome. Only 1 patient experienced a DLT with neutropenia and diarrhoea at 60/60 mg/m(2). Dose escalation was limited to 60/80 mg/m(2) which was the recommended dose for CPT-11/cisplatin alone in NSCLC. Tumour responses included one complete response (CR), 15 partial response (PR), and 7 no change (NC), and the overall response rate was 69.6% (95% confidence interval (CI) 47.1-86.8%). This combined modality is tolerable, and CPT-11/cisplatin of 60/80 mg/m(2) in this modality is recommended for phase II study.

Adult↗

PubMed2001

Functional brain networks in Parkinson's disease.

With the advent of new methods of network analysis, we have utilized metabolic data acquired through positron emission tomography (PET) to identify disease-related patterns of functional pathology in the movement disorders. In Parkinson's disease (PD), we have used [(18)F]-fluorodeoxyglucose (FDG)/PET to identify a disease-related regional metabolic covariance pattern characterized by lentiform and thalamic hypermetabolism associated with regional metabolic decrements in the lateral premotor cortex, the supplementary motor area, the dorsolateral prefrontal cortex, and the parieto-occipital association regions. The expression of this network is modulated in a predictable fashion by levodopa therapy and by stereotaxic interventions for PD.We have extended this network analytical approach from studies of glucose metabolism in the resting state to dynamic studies of brain activation during motor performance. These PET studies utilized [(15)O]-water (H(2) (15)O) to measure cerebral blood flow activation responses during the execution of simple and complex motor tasks. In addition to the modulation of abnormal resting metabolic networks, effective PD therapy can enhance brain activation responses during motor execution, with specific regional associations with improvements in timing and spatial accuracy.This approach is also useful in identifying specific brain networks mediating the learning of sequential information. We have found that the normal relationship between brain networks and learning performance are altered in the earliest stages of PD with a functional shift from striatal to cortical processing. Brain activation PET studies during therapeutic interventions for PD demonstrate how normal brain-behavior relationships can be restored with successful therapy. Thus, functional brain imaging with network analysis can provide insights into the mechanistic basis of basal ganglia disorders and their treatment.

Antiparkinson Agents↗

PubMed2001

A common mutation of low-density lipoprotein receptor gene is associated with essential hypertension among Japanese.

Candidate genes offer one approach to the identification of the genetic susceptibility to hypertension. A common gene variant of the low-density lipoprotein (LDL) receptor gene (LDLR) that affects plasma LDL metabolism within the normolipidaemic range, may be such a candidate gene. A common mutation of LDLR, C1773T, was associated with lipid metabolism such that the T1773 allele increased plasma LDL levels in a Caucasian population. The present study examined whether C1773T/LDLR was associated with essential hypertension in a Japanese population. Subjects with essential hypertension (EHT, n = 300) with a family history of hypertension, and controls (NT, n = 310, sex- and age-matched with EHT) were recruited from among out-patients at Osaka University Hospital. A C1773T substitution at codon 570 in LDLR was determined using PCR-Hinc II-RFLP. It was revealed that the C1773 allele was significantly more frequent (0.89) among hypertensive patients (chi2 = 9.58, P < 0.01) than normotensives (0.83), the calculated odds ratio being 1.7 (95% CI: 1.2-2.4). The effect of the T1773 allele on increasing cholesterol was significant in normotensives without antihyperlipidaemic medication, but not in hypertensives. After adjustments of confounding factors, the estimated odds ratio for hypertension in the subjects with C1773 homozygote increased to 2.1 (95% CI: 1.3-3.5), suggesting that this polymorphism is an independent risk factor for hypertension. Our results show that the C1773 mutant of LDLR increases susceptibility to hypertension, but not via hypercholesterolaemia.

Asian People↗

PubMed2001

The isochronic band hypothesis and climbing fibre regulation of motricity: an experimental study.

The dynamic organization of the olivocerebellar afferent input to Purkinje cells was examined in rat cerebellar cortex. The distribution of synchronous Purkinje cell complex spike activity was characterized, bilaterally, utilizing multiple electrode recordings in crus IIa folium under ketamine anaesthesia. The results confirmed the existence of rostrocaudal complex spike isochronicity bands with a mediolateral width of 500 microm. For a given band, no finer spatial submicrostructures could be discerned at a first-order approximation (two-dimensional projection). Closer analysis determined that isochronicity between bands is not continuous in space but demonstrates discrete discontinuities at the mediolateral boundaries. Principal component multivariate analysis revealed that the first principal component of the spatio-temporal variance is synchronicity along the rostrocaudal band with a decreased level of coupling in the mediolateral direction at the band boundary. Furthermore, this discrete banding isochronicity is organized by the distribution of feedback inhibition from the cerebellar nuclei on to the inferior olive nucleus. The usual multiple band structure can be dynamically altered to a single wide-band dynamic architecture, or to other patterns of activity, as may be required by movement coordination.

Animals↗

PubMed2001

Bilaterally synchronous complex spike Purkinje cell activity in the mammalian cerebellum.

Complex spike activity was simultaneously recorded from 96 Purkinje cells in the rat cerebellar cortex. Rostrocaudal complex spike synchronicity bands were studied in crus I, IIa and IIb and in vermal lobule 6c. Detailed analysis in crus IIa revealed that complex spike activity was staggered sequentially with a 20--50 cm/sec 'propagation velocity' in the mediolateral direction, and that such activity was bilaterally synchronous. The 'propagation' of complex spike activity was symmetrical between right and left crus IIa. Temporally, the neurons that aligned in the rostrocaudal direction typically generated complex spikes close to simultaneously. The correlation of complex spike firing was high between crus IIa and crus IIb, moderate between crus IIa and vermis 6c, and relatively low between Purkinje cells in crus I and crus IIa. These results indicate that, whilst discrete boarders exist between different isochronicity bands, these bands do communicate with each other in the mediolateral direction via slow 'propagation waves' that loosely bind their activity. The results indicate that the olivocerebellar system is organized, bilaterally, to take advantage of the timing signals generated at the inferior olive nucleus.

Action Potentials↗

PubMed2001

The prevalence of renal cell carcinoma: a nation-wide survey in Japan in 1997.

BACKGROUND: The present study was conducted to investigate the incidence of renal cell carcinoma by sex, age group and different regions in Japan. METHODS: The survey was conducted from the beginning of January 1997 to the end of December 1997. A total of 1306 Institutions in all 47 prefectures throughout Japan were requested to register cases. RESULTS: There were 6358 persons with renal cell carcinoma, consisting of 4372 men and 1986 women. The age-specific incidence rates showed a peak in the age group of 65-70 years in both men and women. The crude incidence rates per 100 000 population for men and women were 7.1 and 3.1, respectively, and age-standardized incidence rates per 100 000 population for men and women were 4.9 and 1.8, respectively. The incidence rates in the Hokkaido region were significantly higher than in other regions (P < 0.05), among which there was no significant difference in incidence rates. CONCLUSIONS: The present study showed that the incidence rates of renal cell carcinoma in Japan were approximately the same as among Japanese in Los Angeles. The rates were, however, lower than North American and European countries, but higher than China, Central or South American countries and African countries. The reasons for the high incidence of renal cancer in the Hokkaido region are not entirely clear. Further epidemiologic research is required.

Adult↗

PubMed2001

A unique spacer domain of synaptotagmin IV is essential for Golgi localization.

Synaptotagmin (Syt) family members consist of six separate domains: a short amino terminus, a single transmembrane domain, a spacer domain, a C2A domain, a C2B domain and a short carboxyl (C) terminus. Despite sharing the same domain structures, several synaptotagmin isoforms show distinct subcellular localization. Syt IV is mainly localized at the Golgi, while Syt I, a possible Ca(2+)-sensor for secretory vesicles, is localized at dense-core vesicles and synaptic-like microvesicles in PC12 cells. In this study, we sought to identify the region responsible for the Golgi localization of Syt IV by immunocytochemical and biochemical analyses as a means of defining the distinct subcellular localization of the synaptotagmin family. We found that the unique C-terminus of the spacer domain (amino acid residues 73-144) between the transmembrane domain and the C2A domain is essential for the Golgi localization of Syt IV. In addition, the short C-terminus is probably involved in proper folding of the protein, especially the C2B domain. Without the C-terminus, Syt IVdeltaC proteins are not targeted to the Golgi and seem to colocalize with an endoplasmic reticulum (ER) marker (i.e. induce crystalloid ER-like structures). On the basis of these results, we propose that the divergent spacer domain among synaptotagmin isoforms may contain certain signals that determine the final destination of each isoform.

Amino Acid Sequence↗

PubMed2001

Effects of risperidone on event-related potentials in schizophrenic patients.

In order to examine the effects of risperidone on cognitive impairment in schizophrenia, event-related potentials (ERPs) were recorded before and after switching from conventional neuroleptics to risperidone in schizophrenic patients. ERPs were recorded during two auditory discrimination tasks (an oddball task and a distraction task) in 10 medicated schizophrenic patients during conventional neuroleptic and risperidone treatments. The amplitudes and latencies of N 100 and P300 component were measured in ERPs for target stimuli in the oddball task and in ERPs for target and novel stimuli in the distraction task. Although N 100 amplitude and latency and P 300 amplitude did not change significantly after switching the drug compared to that during conventional neuroleptic treatment, P 300 latency for target stimuli shortened significantly during risperidone treatment in both tasks, accompanied by the shortening of the reaction time in the distraction task. The P 300 latency change did not correlate with the change of the severity of psychopathology. These findings suggest that risperidone may speed the information processing in schizophrenic patients, contributing to the improvement of cognitive functions.

Adult↗