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Biomedical subjects

T Kato

Publications and source records attributed to T Kato.

At least 19 recordsLinked to original sources
PubMed2007

Ten-year experience in porto-caval hemitransposition for liver transplantation in the presence of portal vein thrombosis.

Porto-caval hemitransposition (PCH) in liver transplantation allows revascularization of the liver when the porto-mesenteric axis is thrombosed. We, here, review our experience over an 11-year period. A total of 23 patients underwent liver transplantation using PCH. Immunosuppression was based on tacrolimus, with sirolimus used in case of renal insufficiency. Most common diagnoses were hepatitis C, Laennec's, Budd-Chiari and cryptogenic cirrhosis. Six patients needed splenectomy prior to transplant, 5 during transplant, 1 post-transplant, 11 had no splenectomy. Overall survival was 60% at 1 year and 38% at 3 years, with 10 of 23 patients currently alive and the longest survivor at 9.3 years. Most common cause of death was sepsis/multisystem organ failure, followed by pulmonary embolism. A total of 7/23 patients experienced post-operative gastrointestinal bleeding episodes, 6/23 patients developed thrombosis of the vena cava (median 162 days post-op). Post-operative ascites was noted in almost all patients. Renal dysfunction was commonly seen even after the first month post-transplant. PCH offers a feasible option for liver transplantation in those patients with complex thrombosis of the mesenteric and portal circulation.

Adult↗
PubMed2006

Measurement of atmospheric neutrino flux consistent with tau neutrino appearance.

A search for the appearance of tau neutrinos from nu(mu) <--> nu(tau) oscillations in the atmospheric neutrinos has been performed using 1489.2 days of atmospheric neutrino data from the Super-Kamiokande-I experiment. A best fit tau neutrino appearance signal of 138+/-48(stat)-32(+15)(syst) events is obtained with an expectation of 78+/-26(syst). The hypothesis of no tau neutrino appearance is disfavored by 2.4 sigma.

Journal Article↗
PubMed2006

Patterns of masseter muscle activities during sleep in guinea pigs.

Basic neurophysiological mechanisms for sleep bruxism remain unknown. Analyses of masseter muscle activity during sleep in guinea pigs have shown that the duration and activity of masseter bursts differ between non-rapid eye movement (NREM) and rapid eye movement (REM) sleep and that some repetitive burst episodes do occur. Furthermore, masseter bursts occurred in association with a transient heart rate increase. These results suggest that various patterns of masseter bursts occur in association with transient arousal activity during sleep in guinea pigs.

Animals↗
PubMed2006

Postoperative incision hernia in patients with abdominal aortic aneurysm and aortoiliac occlusive disease: a systematic review.

OBJECTIVES: We conducted a systematic review to determine the incidence of postoperative incision hernia in patients with abdominal aortic aneurysm compared to those with aortoiliac occlusive disease. METHODS: Studies which compared the incidence of postoperative incision hernia in patients with abdominal aortic aneurysm and aortoiliac occlusive disease undergoing midline incision for arterial reconstruction were identified. MEDLINE was searched for articles published between January 1966 and September 2005. RESULTS: Our search identified seven studies including data on 1132 patients, 719 with abdominal aortic aneurysm and 413 with aortoiliac occlusive disease. Pooled analysis demonstrated that patients with abdominal aortic aneurysm had a 2.9-fold increased risk of inguinal hernia (odds ratio 2.85, 95% confidence interval 1.71-4.77, p<0.0001), and a 2.8-fold risk of incisional hernia (2.79, 1.88-4.13, p<0.0001). Adjusting for other known risk factors patients with aortic aneurysm had a 5-fold increased risk of incisional hernia (5.45, 2.48-11.94, p<0.0001). CONCLUSIONS: Patients with abdominal aortic aneurysm appear to have an approximately 3-fold increased risk for both inguinal and postoperative incision hernia compared to patients with aortoiliac occlusive disease. A large multi-centre prospective study is needed to confirm the results of this review.

Aorta, Abdominal↗
PubMed2006

Protective effect against 17beta-estradiol on neuronal apoptosis in hippocampus tissue following transient ischemia/recirculation in mongolian gerbils via down-regulation of tissue transglutaminase activity.

We analyzed the protective effect of 17beta-estradiol (17beta-ED) injection against delayed neuronal death in the hippocampus tissue of the brain in Mongolian gerbils after transient ischemia/recirculation treatment, especially in relation with bcl-2 gene expression and enzymatic activity changes of caspase-3 and tissue transglutaminase (tTGase). Daily intraperitoneal injection of 17beta-ED to the animal after the ischemia stimulated the expression of an apoptosis suppressor gene, bcl-2, in the hippocampal tissue for a week. The gradually increasing apoptotic enzyme activity of caspase-3 and increased number of TUNEL positive fragmented neuronal nuclei caused by ischemic attack in the gerbil brain were clearly suppressed by 17beta-ED administration. The reduced activity and enzyme protein of tTGase, a neurodegenerative marker of apoptosis in the hippocampus after ischemia, were also restored to nearly normal levels by 17beta-ED injection. These results suggest that daily 17beta-ED administration to the gerbil after transient ischemic insult with progressing neuronal deteriorative changes in hippocampus tissue can effectively prevent apoptotic changes through a molecular cascade involving gene expression regulation.

Animals↗
PubMed2006

Microarray analysis of differentially expressed fetal genes in placental tissue derived from early and late onset severe pre-eclampsia.

Although it has been well documented that pre-eclampsia is caused by a combination of maternal and fetal susceptibility genes, little is known about the precise etiology of this complicated disorder. To investigate how the expression of fetal genes contributes to the mechanisms underlying the progression of this disease, we have analyzed differentially expressed genes using placentas from 13 normal pregnancies and 14 pregnancies with severe pre-eclampsia. We performed genome-wide expression profiling using high-density oligonucleotide microarrays, followed by validation using real-time PCR. Among the 47,000 genes that were screened in the microarray, 137 genes were found to be differentially expressed between normal and pre-eclamptic tissues. Among these candidates, 70 were up-regulated and 67 were down-regulated. The up-regulated genes included leptin and inhibin A, which are well-known biological markers for pre-eclampsia, as well as FLT1, which was recently proved to be tightly linked with the etiology of this disease. Gene ontology analysis further revealed several biological processes that could be associated with the development of pre-eclampsia, including response to stress, host-pathogen interactions, lipid metabolism, and carbohydrate metabolism. Analyses of biological mechanisms highlighted some important pathways that may be involved in this disorder, such as the TGF-beta and CEBPA-related pathways. Furthermore, when our present subjects were classified as either severe cases of early onset or late onset pre-eclampsia, the expression of 11 genes could be correlated with the severity of this disorder. These genes may therefore prove to be novel biological markers by which the severity of this condition could be predicted. Our data are likely to be a useful future resource in the elucidation of the disease-process and in the identification of novel markers for pre-eclampsia.

Adult↗
PubMed2006

Genetic characterization of Batai virus indicates a genomic reassortment between orthobunyaviruses in nature.

Two viruses were isolated from bovine blood in the southernmost part of Japan in 1994 and 2001, respectively. Genetic analyses showed that the viruses were Batai virus of the genus Orthobunyavirus of the family Bunyaviridae. The sequencing of three genomic RNA segments of the Japanese and Malaysian Batai virus strains revealed that the M RNA segment of Batai virus had high sequence identity with that of Ngari virus. Our results indicate that Ngari virus is a genetic reassortant with S and L RNA segments from Bunyamwera virus and an M RNA segment from Batai virus.

Animals↗
PubMed2006

Phase I/II study of docetaxel and S-1 in patients with advanced gastric cancer.

The aims of this phase I/II study of docetaxel and S-1 were to determine the dose-limiting toxicity (DLT), maximum-tolerated dose (MTD), and recommended dose (RD) in the phase I part and to explore the tumour response, survival and safety in the phase II part. Patients with histologically- or cytologically confirmed unresectable or recurrent gastric cancer were eligible. Treatment consisted of intravenous docetaxel on day 1 (starting dose 50 mg m(-2)) and oral S-1 at a fixed dose of 40 mg m(-2) twice daily on days 1-14, every 4 weeks up to six cycles. Nine patients took part in the phase I portion of the study. The MTD of docetaxel was determined to be 50 mg m(-2), with the DLTs of grade 3 infection associated with grade 3 neutropenia and grade 4 neutropenia during S-1 administration. The RD of docetaxel was 40 mg m(-2) in combination with S-1 40 mg m(-2) b.i.d. The efficacy and safety of this regimen was therefore assessed in 46 patients with at least one measurable lesion. The overall response rate and estimated median overall survival were 46% (95% CI, 31-61%) and 14.0 months (8.3-17.3 months), respectively. The most common grade 3/4 toxicity was neutropenia (67% of patients), which was predictable and manageable. This regimen showed promising activity with moderate toxicities in advanced gastric cancer.

Adenocarcinoma↗
PubMed2006

Expression of proteinase-activated receptors (PAR)-2 in articular chondrocytes is modulated by IL-1beta, TNF-alpha and TGF-beta.

OBJECTIVE: To investigate the modulation of expression of proteinase-activated receptor-2 (PAR-2) in articular chondrocytes by inflammatory cytokines. DESIGN: Articular synovium and cartilage tissues were collected from eight patients with osteoarthritis (OA), and three patients without arthropathy ("normal"). Chondrocytes were stimulated with interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha or transforming growth factor (TGF)-beta1. The expression of PAR-2 was detected using reverse transcriptase-polymerase chain reaction (PCR), Western blotting and immunofluorescence. Quantitative PCR was performed to assess the expression levels of PAR-2 messenger RNA (mRNA). RESULTS: The expression of PAR-2 mRNA was demonstrated in both OA and normal chondrocytes as well as in synovial fibroblasts. However, the level of PAR-2 in OA chondrocytes was much higher than in normal chondrocytes. Long-term culture revealed that PAR-2 mRNA expression was maintained up to three passages in OA but not in normal chondrocytes. IL-1beta and TNF-alpha both upregulated PAR-2 expression in normal and OA chondrocytes. In contrast, TGF-beta1 significantly decreased expression of PAR-2 in OA chondrocytes but increased PAR-2 in normal chondrocytes. CONCLUSIONS: Overexpression of PAR-2 in OA chondrocytes is upregulated by proinflammatory cytokines IL-1beta and TNF-alpha, and down-regulated by regulatory cytokine TGF-beta1. PAR-2 may be involved in the pathogenesis of OA.

Aged↗
PubMed2006

A complex polymorphic region in the brain-derived neurotrophic factor (BDNF) gene confers susceptibility to bipolar disorder and affects transcriptional activity.

Previous studies have suggested that genetic variations in the brain-derived neurotrophic factor (BDNF) gene may be associated with several neuropsychiatric diseases including bipolar disorder. The present study examined a microsatellite polymorphism located approximately 1.0 kb upstream of the translation initiation site of the BDNF gene for novel sequence variations, association with bipolar disorder, and effects on transcriptional activity. Detailed sequencing analysis revealed that this polymorphism is not a simple dinucleotide repeat, but it is highly polymorphic with a complex structure containing three types of dinucleotide repeats, insertion/deletion, and nucleotide substitutions that gives rise to a total of 23 novel allelic variants. We obtained evidence supporting the association between this polymorphic region (designated as BDNF-linked complex polymorphic region (BDNF-LCPR)) and bipolar disorder. One of the major alleles ('A1' allele) was significantly more common in patients than in controls (odds ratio 2.8, 95% confidential interval 1.5-5.3, P=0.001). Furthermore, a luciferase reporter gene assay in rat primary cultured neurons suggests that this risk allele (A1) has a lower-transcription activity, compared to the other alleles. Our results suggest that the BDNF-LCPR is a functional variation that confers susceptibility to bipolar disorder and affects transcriptional activity of the BDNF gene.

Adult↗
PubMed2006

Zoom endoscopic monitoring of small bowel allograft rejection.

BACKGROUND: The small bowel has been successfully transplanted in patients with irreversible intestinal failure. This report aims to describe endoscopic monitoring of small bowel rejection. METHODS: A magnification endoscope (zoom endoscope) was used in this study. In the first part of the study (October 1998 to March 2000, 271 endoscopy sessions), the specific endoscopic findings that correlated with rejection were determined. An analysis then was performed on data from the second period (March 2001 to November 2002, 499 sessions) to evaluate the zoom endoscope's accuracy in monitoring rejection. RESULTS: Specific endoscopic findings of rejection found in the first period included background erythema, villous congestion, blunted villous tip, and shortened villous height. When the rejection was successfully treated, endoscopic appearance returned to normal. On the basis of these findings, five endoscopic criteria (villous shortening, villous blunting, background erythema, villous congestion, and mucosal friability) were used to score endoscopic sessions in the second period. Endoscopic diagnosis of rejection was compared with histology. Adult patients showed a sensitivity of 45%, a specificity of 98%, a positive predictive value of 82%, and a negative predictive value of 88%. In pediatric patients, these values were, respectively, 61%, 84%, 57%, and 86%. On 59 distinct occasions (30 in period 1 and 29 in period 2) in which the results were endoscopy negative yet biopsy positive (mild) for rejection, we elected not to treat these rejections on the basis of clinical evaluation, and 58 (98%) resolved without further therapy. CONCLUSIONS: With the use of magnification, endoscopy is a useful tool for monitoring acute rejection in the small bowel allograft.

Adolescent↗
PubMed2006

Nonequilibrium thermodynamics of highly charged ion plasmas.

Thermodynamics of irreversible processes is applied to study the interaction of matter and radiation field in nonlocal thermodynamic equilibrium. The rate of entropy production of matter and radiation field, in contact with a free electron reservoir in local thermodynamic equilibrium, is obtained using the conjugate variables of the state variables. When approximating the electronic configuration populations by an effective Boltzmann law, the corresponding effective temperature is determined by minimizing the rate of entropy production at fixed electronic density, electronic temperature, and radiation field. Numerical results and comparisons with recent experiment for photoionized iron plasma are presented and discussed.

Journal Article↗
PubMed2006

Unbinding and preunbinding in surfactant solutions.

We propose models for the first-order unbinding transition of lyotropic lamellae in surfactant solutions. The coupling between the surfactant volume fraction and the elastic degree of freedom is considered so that the net attractive interaction between the surfactant molecules is enhanced. The elastic degree of freedom can be either (i) a membrane elastic degree of freedom or (ii) a bulk elastic degree of freedom. The phase behaviors of these two models are analyzed. For both cases, the unbinding transition becomes first order when the coupling is strong enough. We determine the associated preunbinding line which separates two lamellar phases having different repeat distances.

Journal Article↗
PubMed2006

Survival benefit of high ligation of the inferior mesenteric artery in sigmoid colon or rectal cancer surgery.

BACKGROUND: The aim of this study was to assess the impact of inferior mesenteric artery (IMA) root nodal dissection before high ligation of the artery on survival in patients with sigmoid colon or rectal cancer. METHODS: Data on 1188 consecutive patients who underwent resection for sigmoid colon or rectal cancer, with high ligation of the IMA, were identified from a prospective database (April 1965 to December 1999). Survival of patients with involvement of nodes along the IMA proximal to the origin of the left colic artery (root nodes, station 253) through the bifurcation of the superior rectal artery (trunk nodes, station 252) was determined. RESULTS: Twenty patients (1.7 per cent) had metastatic involvement of station 253 lymph nodes and 99 (8.3 per cent) had metastases to station 252. The 5- and 10-year survival rates of patients with metastases to station 253 were 40 and 21 per cent, and those for patients with metastases to station 252 were 50 and 35 per cent, respectively. CONCLUSION: High ligation of the IMA allows curative resection and long-term survival in patients with cancer of the sigmoid colon or rectum and nodal metastases at the origin of the IMA.

Adult↗
PubMed2006

Routine use of auxiliary partial orthotopic liver transplantation for children with fulminant hepatic failure: Preliminary report.

Auxiliary partial orthotopic liver transplantation (APOLT) has been performed for both metabolic disorders and fulminant liver failure (FHF). When the native liver regenerates, the patients with FHF who undergo APOLT have a chance to withdraw immunosuppression. It may be most beneficial for children. This preliminary report describes our start to routinely offer APOLT as an option to standard OLT for children with FHF in 2005. Six children (ages 8 months to 8 years) received APOLT: 1 in 1996 and the others in 2005 and 2006. The donor ages ranged from 4 to 40 years. We used either a left lateral segment or a left lobe graft. The recipient left lobe, which was removed, showed submassive to massive necrosis at the time of transplantation. All children are alive and well. The first patient who received APOLT in 1996 is currently off immunosuppression with a fully recovered native liver; the grafted liver underwent complete atrophy. The 5 remaining subjects are receiving reduced levels of immunosuppression with close monitoring. Their serial liver biopsy specimens show slight to significant recovery. One developed hepatic artery thrombosis, requiring retransplantation. The native liver was retained at the time of retransplantation (redo APOLT). Other postoperative complications included a bile leak (n = 1), invasive mucomycosis of the arm (preexisting condition; n = 1), biliary stricture (n = 1), and acute cellular rejection (n = 3). Posttransplantation length of stay was 6 to 60 days (median, 15 days). In conclusion, APOLT can be safely performed in children with FHF displaying short-term outcomes comparable to standard transplantations.

Adolescent↗
PubMed2006

Pediatric liver transplant with Campath 1H induction--Preliminary report.

UNLABELLED: Since Campath 1H (C1H) has been successfully used in adult liver transplant recipients since 2001 in our program, we started to use it in children. PATIENTS AND METHODS: C1H induction was employed in 10 children with autoimmune hepatitis (AIH) (n = 6), primary sclerosing cholangitis (PSC) (n = 1), biliary atresia (n = 1), glycogen storage disease (n = 1), and Wilson's disease. Eight were primary transplants, and two retransplants. Patients ages ranged from 5 to 17 years. C1H was administered at a dose of 0.3 mg/kg on days 0, 4, and 7. Tacrolimus level was maintained at 5 to 10 ng/mL. No patient received maintenance steroids posttransplantation except two who were on steroid therapy at the time transplant. They were prescribed small doses of maintenance steroids. Median follow-up of C1H recipients was 679 days (range 115-1143). RESULTS: Postoperative courses were mostly uneventful except for one retransplant recipient who required prolonged hospitalization (40 days) for rehabilitation. Median hospital stay was 12 days (range 7-40 days). All 10 patients in the C1H group are currently alive and well with stable graft function. No opportunistic infection was observed in these patients to date. We compared six patients with AIH who received C1H to the historic control of 10 recipients with AIH who received conventional immunosuppression (tacrolimus + steroid). The patients treated with C1H showed significantly prolonged rejection-free survival. CONCLUSION: In our preliminary experience, C1H induction was well tolerated in pediatric liver recipients. Rejections-free survival was prolonged among recipients with AIH despite a low level of maintenance immunosuppression.

Adolescent↗
PubMed2006

Brain olfactory activation measured by near-infrared spectroscopy in humans.

In recent years, near-infrared spectroscopy (NIRS) has been used to study functional activation of various areas of the brain. This is based on the assumption that an increase in the recorded oxygenated haemoglobin (HbO2) concentration represents an increase in blood flow, which in turn reflects neuronal activation. The aim of this preliminary study was to use NIRS to monitor the activity of the olfactory cortex, as mirrored by the haemodynamic response, when subjects were exposed to olfactory stimuli. A NIRO 300 (Hamamatsu Photonics, Hamamatsu, Japan) device was used. The optodes were placed on the right forehead and right temporal, parietal and occipital regions. Changes in the concentration of HbO2 and deoxygenated haemoglobin during olfactory stimulation were monitored. Olfactory stimulation was performed with vanilla essence, strawberry essence and scatol. During olfactory stimulation, cerebral HbO2 concentration increased over the frontal region. However, in the temporal, parietal and occipital regions, little or no HbO2 changes were recorded. This study shows that human brain cortical activation following olfactory stimulation can be recorded by NIRS. This NIRS analysis may therefore provide the basis for future development of an objective olfactory test in humans.

Adult↗