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Biomedical subjects

K Fukao

Publications and source records attributed to K Fukao.

At least 19 recordsLinked to original sources
PubMed2006

Outcome of laparoscopic live donor nephrectomy in 2005: National survey of Japanese transplantation centers.

The increased acceptance of laparoscopic nephrectomy (LN) has been a driving force for live donor kidney transplantation. However, the outcomes of LN in live donors has not yet been clarified in Japan. In this study, we surveyed 125 Japanese kidney transplantation centers to investigate the current status of live donor LN. Of 125 centers, the 98 that responded had performed 695 live donor nephrectomies. Among these centers, 43 had performed LN. Among the 695 nephrectomies, 441 donors had undergone LN and 254, open nephrectomies. In 43 centers, 16 were performed as hand-assisted (HA) LN; 20, non-HA; 3, both HA and non-HA; and 5 laparoscope-assisted. Ten centers used a peritoneal approach; 30, a retroperitoneal; and 3, both. In 441 LN donors, 1 had a life-threatening complication of deep venous thrombosis and survived. Blood transfusions were performed in 7 donors. Open conversions from LN were necessary in 24. Minor complications not requiring prolonged hospital stay were reported in 52. The mortality of LN was zero. In contrast, among the 441 recipients, 1 case was reported as primary nonfunction after venous misadventure in the operation and 30 recipients needed hemodialysis after transplantation because of delayed graft function. Urinary tract complications were noted in 11 recipients. This survey presented the current status of the procedure, providing a base for informed consent from potential donors.

Blood Loss, Surgical↗
PubMed2005

Aging phenomena in poly(methyl methacrylate) thin films: memory and rejuvenation effects.

The aging dynamics in thin films of poly(methyl methacrylate) (PMMA) have been investigated through dielectric measurements for different types of aging processes. The dielectric constant was found to decrease with increasing aging time at an aging temperature in many cases. An increase in the dielectric constant was also observed in the long-time region (>or=11 h) near the glass transition temperature for thin films with thickness less than 26 nm . In the constant-rate mode including a temporary stop at a temperature T(a) , the memory of the aging at T(a) was found to be kept and then to be recalled during the subsequent heating process. In the negative-temperature cycling process, a strong rejuvenation effect has been observed after a temperature shift from the initial temperature T1 to the second temperature T2 (= T1 +DeltaT) when DeltaT approximately -20 K . Furthermore, a full memory effect has also been observed for the temperature shift from T2 to T1 . This suggests that the aging at T1 is totally independent of that at T2 for DeltaT approximately -20 K. As /DeltaT/ decreases, the independence of the aging between the two temperatures was found to be weakened-i.e., the effective time, which is a measure of the contribution of the aging at T1 to that at T2 , is a decreasing function of /DeltaT/ in the negative region of DeltaT . As the film thickness decreases from 514 nm to 26 nm, the /DeltaT/ dependence of the effective time was found to become much stronger. The contribution of the aging at T2 to that at T1 disappears more rapidly with increasing /DeltaT/ in thin-film geometry than in the bulk state.

Journal Article↗
PubMed2004

Expression of the chicken peroxisome proliferator-activated receptor-gamma gene is influenced by aging, nutrition, and agonist administration.

Peroxisome proliferatior-activated receptor-gamma (PPARgamma) is a transcription factor that modulates lipid and glucose metabolism in mammals. The aim of the present study was to investigate whether chicken PPARgamma is expressed in tissues in a similar manner to mammalian PPAR and whether it is involved in the regulation of lipid metabolism, particularly in the regulation of fat accumulation in adipose tissue and ovaries. In 30-wk-old chickens, PPARgamma mRNA was detected in most tissues that were examined. Of those tissues expressing chicken PPARgamma mRNA, the lowest expression levels were found in adipose tissue, the tissue that in mammals was shown to express the highest levels of PPARgamma mRNA. Chicken PPARgamma mRNA expression in abdominal adipose tissue tended to increase with age, as shown by higher expression levels at 6 wk than at 1 and 2 wk of age. With regard to nutritional modulation, PPARgamma mRNA levels in abdominal adipose tissue were significantly higher in broiler chickens fed for 7 d a diet containing 8% safflower oil (18:2-rich) or linseed oil (18:3-rich) compared with chickens fed a diet containing olive oil (18:1-rich). In contrast, feeding a 3% cholesterol-supplemented diet for 7 d resulted in no changes to adipose PPARgamma mRNA expression. In broiler chickens orally administered troglitazone, a PPARgamma ligand, abdominal fat pad weight and PPARgamma and lipoprotein lipase (LPL) mRNA levels were significantly increased relative to those of control chickens. Levels of PPARgamma mRNA in liver, skeletal muscle, and ovaries were increased with the onset of egg laying, whereas in adipose tissue the level of PPARgamma mRNA was decreased. These findings suggest that PPARgamma plays an important role in the regulation of fat deposition and egg production and the characteristic pattern of PPARgamma mRNA expression may be indicative of specific differences in the lipid and glucose metabolism of chickens compared with mammals.

Abdomen↗
PubMed2003

Dynamics in thin polymer films by dielectric spectroscopy.

After a brief review on the recent developments of the dielectric studies in thin polymer films, our recent results on dynamics in thin films of poly(methyl methacrylate) (PMMA) and polyisoprene (PIP) are shown. For PMMA, the tacticity effect on dynamics in thin films has been investigated and the disappearance of this effect was found below a critical thickness. For PIP, the motion of entire polymer chains, namely, the normal mode, has been investigated. The dielectric-loss spectrum of the normal mode is much more sensitive to the decrease in film thickness than that due to the [Formula: see text]-process. The broadening of dielectric-loss spectra of the normal mode is observed for film thicknesses below about 150 nm, while the position of the loss peak does not change in the thickness range down to about 50 nm. Anomalous increase in dielectric loss between the [Formula: see text]-process and the normal mode was observed, which is consistent with the recent report on the existence of an additional relaxation process.

Journal Article↗
PubMed2001

Accumulation of losses of heterozygosity and multistep carcinogenesis in pulmonary adenocarcinoma.

Sixty-six replacing growth-type early lung adenocarcinomas, measuring 2 cm or less across their greatest dimension, were used to investigate allelic losses at eight loci on the eight chromosomes carrying the principal cancer-associated genes. In total, 2 (16.7%) of 12 type A tumors (localized bronchioloalveolar carcinoma, LBAC) and 11 (39.3%) of 28 type B tumors (LBAC with alveolar collapse), which correspond to early lung adenocarcinomas including cancers in situ, showed allelic losses in one or more of the regions examined. In contrast, 25 (96.2%) of 26 type C tumors (LBAC with active fibroblastic proliferation), which correspond to small but advanced tumors, showed allelic losses in one or more regions. The change in histology from type A to type C was characterized by a significant rise in the incidence of allelic losses (P < 0.01). Deletions of 3p, 17p, 18q, and 22q increased significantly during malignant progression. In type C tumors that showed heterogeneous histological features, the tumor cells in the central fibrotic areas exhibited more allelic losses than those in the peripheral bronchioloalveolar growths and were, therefore, considered to have progressed to a more advanced stage than the tumor cells in the peripheral regions.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2001

Dynamics of alpha and beta processes in thin polymer films: poly(vinyl acetate) and poly(methyl methacrylate).

Dynamics of thin films of poly(vinyl acetate) (PVAc) and poly(methyl methacrylate) (PMMA) have been investigated by dielectric relaxation spectroscopy in the frequency range from 0.1 Hz to 1 MHz at temperatures from 263 to 423 K. The alpha process, the key process of glass transition, is observed for thin films of PVAc and PMMA as a dielectric loss peak at a temperature T(alpha) in temperature domain with a fixed frequency. For PMMA, the beta process is also observed at a temperature T(beta). For PVAc, T(alpha) decreases gradually with decreasing thickness, and the thickness dependence of T(alpha) is almost independent of the molecular weight (Mw< or =2.4x10(5)). For PMMA, T(alpha) remains almost constant as thickness decreases down to a critical thickness dc, at which point it begins to decrease with decreasing thickness. Contrastingly, T(beta) decreases gradually as thickness decreases to dc, and below dc it decreases drastically. For both PVAc and PMMA, the broadening of the distribution of the relaxation times in thinner films is observed and this broadening is more pronounced for the alpha process than for the beta process. It is also observed that the relaxation strength is depressed as the thickness decreases for both the polymers.

Journal Article↗
PubMed2001

Slow dynamics near glass transitions in thin polymer films.

The alpha process (segmental motion) of thin polystyrene films supported on glass substrate has been investigated in a wider frequency range from 10(-3) Hz to 10(4) Hz using dielectric relaxation spectroscopy and thermal expansion spectroscopy. The relaxation rate of the alpha process increases with decreasing film thickness at a given temperature above the glass transition. This increase in the relaxation rate with decreasing film thickness is much more enhanced near the glass transition temperature. The glass transition temperature determined as the temperature at which the relaxation time of the alpha process becomes a macroscopic time scale shows a distinct molecular weight dependence. It is also found that the Vogel temperature has a thickness dependence, i.e., the Vogel temperature decreases with decreasing film thickness. The expansion coefficient of the free volume alpha(f) is extracted from the temperature dependence of the relaxation time within the free volume theory. The fragility index m is also evaluated as a function of thickness. Both alpha(f) and m are found to decrease with decreasing film thickness.

Journal Article↗
PubMed2001

Requirement for natural killer T (NKT) cells in the induction of allograft tolerance.

In this study, we investigated the role of Valpha14 natural killer T (NKT) cells in transplant immunity. The ability to reject allografts was not significantly different between wild-type (WT) and Valpha14 NKT cell-deficient mice. However, in models in which tolerance was induced against cardiac allografts by blockade of lymphocyte function-associated antigen-1/intercellular adhesion molecule-1 or CD28/B7 interactions, long-term acceptance of the grafts was observed only in WT but not Valpha14 NKT cell-deficient mice. Adoptive transfer with Valpha14 NKT cells restored long-term acceptance of allografts in Valpha14 NKT cell-deficient mice. The critical role of Valpha14 NKT cells to mediate immunosuppression was also observed in vitro in mixed lymphocyte cultures in which lymphocyte function-associated antigen-1/intercellular adhesion molecule-1 or CD28/B7 interactions were blocked. Experiments using IL-4- or IFN-gamma-deficient mice suggested a critical contribution of IFN-gamma to the Valpha14 NKT cell-mediated allograft acceptance in vivo. These results indicate a critical contribution of Valpha14 NKT cells to the induction of allograft tolerance and provide a useful model to investigate the regulatory role of Valpha14 NKT cells in various immune responses.

Adaptation, Physiological↗
PubMed2001

Role of platelet-activating factor in hepatectomy with Pringle's maneuver.

BACKGROUND: Interruption of hepatic inflow is commonly used to reduce blood loss during extensive liver resection, but may cause liver dysfunction. The present study investigated the effects of platelet-activating factor (PAF) antagonist E5880 on total liver warm ischemia and 70% hepatectomy. METHODS: Rabbits were used in this study and were divided into four groups: group 1, those treated with only 70% hepatectomy; group 2, those treated with only 20 min Pringle's maneuver; group 3, those treated with both Pringle's maneuver and 70% hepatectomy without pretreatment; and group 4, those pretreated with PAF antagonist E5880 (0.3 mg/kg) followed by Pringle's maneuver and 70% hepatectomy. The remnant liver function was then evaluated after reperfusion. RESULTS: Seven-day survival rates in both groups 1 and 2 were 100%. E5880 treatment significantly increased 7-day survival rate (group 4: 38% vs group 3: 0%, P < 0.05) after a combination of Pringle's maneuver and 70% hepatectomy. The elevations of serum liver enzymes (GOT, GPT, mGOT, and LDH) were significantly inhibited in group 4 at 1 and 4 h after reperfusion. Portal venous pressure and the energy charge of liver were also significantly improved in group 4, compared with those in group 3. Endothelin-1 levels of arterial and portal venous blood progressively increased after reperfusion; however, there were no significant differences between the two groups. Leukocyte infiltration into the liver was significantly inhibited in group 4. CONCLUSION: E5880 pretreatment has protective effects on liver function after 70% hepatectomy with Pringle's maneuver in rabbits.

Adenine Nucleotides↗
PubMed2001

Solitary schwannoma of the colon: report of two cases.

Some patients with gastrointestinal schwannoma (GIS) have been previously reported in the literature. However, GIS of the colon is quite rare. In addition, it is sometimes difficult to differentiate neurogenic tumors from other soft tissue tumors. We herein describe two cases of schwannoma of the colon, while also reviewing the relevant Japanese literature. The first case, a 73-year-old woman underwent a sigmoidectomy with lymph node dissection following the diagnosis of submucosal tumor. In the second case, a submucosal tumor was located in the cecum of a 44-year-old man. An endoscopic tumor resection was performed in the second case. The resected tumors measured 3.6 and 1.0 cm in maximal diameter, respectively. Microscopically, the tumors consisted predominantly of spindle-shaped cells that proliferated in an interlaced fashion. Mitosis was rarely seen in these tumors. Immunohistochemically, the tumor cells were strongly positive for S-100 protein, weakly positive for glial fibrillary acidic protein, and negative for CD34, alpha-smooth-muscle actin, and cytokeratin (CAM 5.2) in both cases. The tumors in the two cases were both diagnosed to be benign schwannoma of the colon. In general, schwannoma of the gastrointestinal tract is considered to be benign and should therefore be distinguished from other spindle-cell tumors or malignancies. Once diagnosed as schwannoma, extensive surgery should be avoided. Actually, such patients tend to show a good postoperative course with no evidence of recurrence.

Adult↗
PubMed2001

Hepatoid adenocarcinoma of the stomach.

Although gastric cancer occurs frequently in Japan, few cases of hepatoid adenocarcinoma, a cancer with an extremely poor prognosis, have been reported. Here, we describe a 67-year-old Japanese man referred to our hospital with suspected gastric cancer. Gastrointestinal fiberscopy revealed an elevated lesion with a central depression on the lesser curvature, extending from the antrum to the body of the stomach. On the preoperative examinations, abdominal computed tomography scan, magnetic resonance imaging, and abdominal ultrasonography revealed multiple metastases to the liver and no cirrhotic change. The serum level of alpha-fetoprotein (AFP) was markedly elevated (10,084 ng/ml). After a diagnosis of AFP-producing gastric cancer with multiple liver metastases was made, total gastrectomy, without liver resection, was performed. Microscopically, the tumor showed two main histological features. The main part of the tumor resembled moderately differentiated hepatocellular carcinoma, and the rest showed fetal-type adenocarcinoma. Some parts of the hepatoma-like lesion showed periodic acid-Schiff (PAS)-positive granules. Furthermore, the tumor showed diffuse immunohistochemical positivity for AFP, alpha-1 antitrypsin, and alpha-1 antichymotrypsin. According to these histopathological findings, the tumor was diagnosed as hepatoid adenocarcinoma of the stomach. Although anastomotic leakage occurred postoperatively and the liver metastases have increased in size, the patient remains alive 11 months after the operation. Because of the poor prognosis for this histological type of tumor, accurate diagnosis of hepatoid adenocarcinoma is important, and long-term follow-up is required. We describe this rare case of hepatoid adenocarcinoma of the stomach, and review the literature concerning the clinicopathological aspects.

Adenocarcinoma↗
PubMed2001

Increased intracranial pressure in a porcine model of fulminant hepatic failure using amatoxin and endotoxin.

BACKGROUND/AIMS: The purpose of this study was to develop a clinically relevant porcine model of fulminant hepatic failure (FHF) by means of administration of amatoxin and endotoxin. METHODS: Pigs were intraportally administered only saline in group 1 (n = 3), 1 microg/kg of lipopolysaccharide (LPS) in group 2 (n = 4), 0.1 mg/kg of alpha-amanitin in group 3 (n = 5), and amanitin plus LPS in group 4 (n = 9). RESULTS: All the pigs in groups 1 and 2 survived with minimal changes in liver function tests. In contrast to the 60% mortality in group 3, all the pigs in group 4 died within 96 h, with a significant increase in aspartate transaminase at 24 h (9,757 +/- 2,167 IU/I). In addition, they demonstrated severe metabolic disorders, such as serum lactate accumulation, hypoglycemia, coagulopathy, plasma amino acid imbalance, and hyperammonemia. The intracranial pressure significantly increased to 17.8 +/- 2.5 mmHg immediately before death. Reversal of FHF in these pigs following orthotopic liver transplantation confirmed that the toxicity is liver-specific and that the graft liver is unaffected. CONCLUSIONS: This porcine model of FHF induced by a combination of amanitin and LPS will be of much use in the development of new therapies for human FHF.

Amanitins↗
PubMed2001

Treatment strategy for patients with middle and lower third bile duct cancer.

BACKGROUND: The prognosis for patients with middle and lower third bile duct carcinoma remains poor. This study was conducted to identify independent predictors for survival, as well as the patterns of recurrence after curative resection. METHODS: Sixty-seven patients with pathologically verified middle and/or lower third bile duct carcinoma were analysed retrospectively by Cox regression analysis for predictors of survival. RESULTS: The overall 5-year survival rate after resection was 39 per cent, and 0 per cent for patients who did not undergo resection. The 5-year survival rate was 63 per cent in 26 patients without microscopic residual disease (R0), 16 per cent in 25 patients with microscopic residual tumour (R1) and 0 per cent in six patients with macroscopic residual tumour (R2); ten patients did not undergo resection. Radiotherapy improved the 5-year survival rate in eight patients who had R1 resection compared with the rate in 17 patients who underwent resection alone (8 versus 0), but not significantly so (P = 0.137); however, median survival was significantly longer (P = 0.004) in six patients who had R2 resection compared with that in ten inoperable patients (11.4 versus 3.5 months). Multivariate analysis revealed that the primary tumour and tumour node metastasis (TNM) stage were independent predictors of survival; 13 clinicopathological factors were not independent prognostic factors. Of 26 patients having R0 resection, one had a locoregional relapse only, six had distant metastases only, and five had both types of recurrence. The liver was the most frequent site for metastasis, and microscopic venous invasion (MVI) in the primary tumour was a significant predictor of liver metastasis. CONCLUSION: Curative (R0) resection is only one step in curing cancer, and radiotherapy may play a beneficial role in controlling locoregional residual tumour. MVI could be a useful indicator of when systemic adjuvant therapy should be implemented to prevent liver metastasis after R0 resection, although no effective systemic treatment has yet been developed.

Adult↗
PubMed2001

Protection against Fas-mediated and tumor necrosis factor receptor 1-mediated liver injury by blockade of FADD without loss of nuclear factor-kappaB activation.

OBJECTIVE: To investigate the role of FADD (Fas-associated protein with death domain) in Fas and tumor necrosis factor receptor 1 (TNFR1)-mediated hepatic injury and inflammatory response in vivo. SUMMARY BACKGROUND DATA: Fas and TNFR1 are cell surface molecules that trigger apoptosis or inflammation on engagement by a specific ligand or antibody. FADD is recruited to the cytoplasmic domain of these receptors on their activation and works as a common mediator to induce apoptosis. It is known that a blockade of FADD can inhibit apoptosis mediated by Fas or TNFR1 in vitro. However, it is not known whether the blockade can prevent organ injury and whether the inflammatory cascade is affected in vivo. METHODS: A FADD deletion mutant lacking the death effector domain was introduced into mice by transduction with an adenovirus vector, and the effect of this FADD dominant negative mutant was examined in several liver injury models. RESULTS: Hepatic injury induced by anti-Fas monoclonal antibody or tumor necrosis factor (TNF)-alpha plus D-galactosamine was markedly ameliorated by the FADD dominant negative transduction, which abrogated the death rate. Further, the FADD dominant negative transduction efficiently blocked T cell- mediated concanavalin A-induced hepatitis while not affecting TNF-alpha production or TNF-alpha-induced nuclear factor-kappaB activation in the liver. CONCLUSIONS: These results provide the basis for a novel therapeutic modality in which an unfavorable apoptotic process can be inhibited without affecting a favorable response for liver regeneration; this would be relevant to the clinical treatment of acute and chronic liver diseases as well as to some inflammatory disorders with hypercytokinemia, such as sepsis.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Long-term results of donor-specific blood transfusion with cyclosporine in living related kidney transplantation.

Donor-specific blood transfusion (DST) was introduced to achieve better graft survival. However, its benefits are controversial considering the immunosuppression of cyclosporine (CYA) or tacrolimus (Tac), and its long-term effects have not been well discussed. Of the 40 patients who received DST with CYA, 3 (7.5%) became cross-match positive. Of the 37 patients with negative cross-match, 34 patients received a one-haplotype-matched kidney and were compared to patients with one-haplotype-matched kidney transplant without preoperative DST (n = 13). Acute rejection within 3 months after transplant was 29.4% in the DST group, and 15.4% in the non-DST group. All rejection episodes were steroid resistant in the non-DST group. If the graft survival rates were calculated excluding non-immunological graft loss, graft survival rate was 91.0 and 72.8% at 5 and 10 years in the DST group, and 83.3% at 5 and 10 years in the non-DST group, respectively. The two graft survival lines converged 7 years and 7 months after transplantation. No beneficial effect of DST was statistically evident under CYA immunosuppression. In terms of the severity of acute rejection or the onset of chronic rejection, DST induced a small benefit, however, which seemed to disappear within 8 years after transplantation.

Acute Disease↗
PubMed2001

Transition and improvement in surgical treatment for rectal cancer during the last 21 years in our department.

The subject of this study was to examine the net effect of numerous changes in basic strategies, personnel and devices, upon the clinical courses and outcomes of rectal cancer patients. A total of 151 rectal cancer patients who underwent low anterior resection were divided into 4 groups (period 1 to 4) based upon the time period of the operation. They were compared among groups based upon the following parameters: blood loss, operation time, incidence of leakage and urinary dysfunction, incidence of ileus, duration of naso-gastric tube insertion, timing of initial oral feeding and survival. The blood loss during the operations, urinary dysfunction and duration of naso-gastric tube insertion tended to decrease in every period. Timing of initial oral feeding became faster. The operation times, incidence of leakage and ileus were nearly the same in each period. The 5-year survival rates on Dukes' C cases were 100% in period 4, 82.4% in period 3 and 50% in period 2. Survival rates became better. Our net outcome for rectal cancer treatment was satisfactory, because the survival rates became better under function preserving strategies.

Follow-Up Studies↗