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Biomedical subjects

T Taguchi

Publications and source records attributed to T Taguchi.

At least 37 records · Page 2Linked to original sources

Endoscopic diverticulotomy for symptomatic pediatric esophageal diverticula.

There have so far been few reports on esophageal diverticulum in children. We experienced two symptomatic pediatric cases with esophageal diverticulum. Our cases manifested high fever and dysphagia with chest pain during swallowing. The patients underwent endoscopic diverticulotomy. The septum between the diverticulum and the esophagus was cut using the argon plasma coagulation (APC 3000) system. We recommend an endoscopic diverticulotomy as an effective treatment modality for such symptomatic cases.

Adolescent↗

An abnormal distribution of C-kit positive cells in the normoganglionic segment can predict a poor clinical outcome in patients with Hirschsprung's disease.

PURPOSE: The loss or decrease of interstitial cells of Cajal (ICCs) has been implicated in several disorders of human intestinal motility. We have encountered a few cases suffering from severe constipation or enterocolitis resulting in patient death after a definitive operation for HD, even though the normoganglionic intestine had been successfully pulled through. We investigated the distribution of ICCs using c-kit immunostaining in the normoganglionic segment and compared these findings with the clinical outcome after a definitive operation in each case. PATIENTS AND METHODS: The distributions of ICCs were investigated by using c-kit immunostaining in the normoganglionic segment in the resected bowel in 15 cases with HD. The distributions of protein gene product 9.5 (PGP 9.5) as a general neuronal marker and those of NADPH-diaphorase (NADPH-d) as a marker of nitric-oxide neurons were also examined. The numbers of ICCs and neurons were evaluated quantitatively. The histopathological results were compared with the clinical outcome after definitive operation in each case. RESULTS: C-kit immunoreactive cells showed a normal distribution in the normoganglionic segment in 13 cases, while they were markedly (less than 50% compared with the other cases) decreased in 2 cases. The distributions of PGP 9.5 and NADPH-d were almost the same in all cases. The bowel movements of 13 cases showing normal c-kit distribution were satisfactory. In contrast, the bowel movements were impaired in 2 cases with a decreased number of c-kit positive cells. One infant suffered from severe persistent constipation and thus had to undergo a resection of a dilated colon. The other infant died of sepsis due to postoperative enterocolitis and showed a markedly dilated colon. CONCLUSION: A decreased number of c-kit positive cells in the normoganglionic segment can thus allow us to predict a poor clinical outcome after definitive surgery, probably due to poor intestinal motility. Therefore examining the c-kit distribution in a resected bowel specimen in patients with HD should be mandatory in order to select the optimal postoperative treatment regimen for each case.

Child↗

Esophageal atresia with double tracheoesophageal fistula--a case report and review of the literature.

Esophageal atresia with double tracheoesophageal fistula (TEF) is a very rare anomaly, and the accurate preoperative diagnosis of proximal TEF is very difficult. This paper describes a baby girl who presented with esophageal atresia with double, proximal, and distal TEF. The distal TEF was diagnosed before operation, whereas the proximal TEF was found intraoperatively. Overlooking the presence of proximal TEF can lead to increased morbidity and mortality due to severe respiratory infection and the necessity of a second operation. Great care must therefore be taken to not overlook the presence of proximal TEF in patients with this anomaly.

Esophageal Atresia↗

Transplantation of corneal endothelium with Descemet's membrane using a hyroxyethyl methacrylate polymer as a carrier.

AIMS: To evaluate the histology and function of Descemet's membrane transplanted with intact endothelium. METHODS: Japanese white rabbits and human eyebank eyes were used as donors and recipients of Descemet's membrane transplantation. Donor endothelium was hydrodissected by injecting indocyanine green from a limbal incision, and then processed as a corneal scleral button. A 6 mm diameter donor sheet was trephined, and folded in half using a 6 mm diameter polymer as a carrier. Recipient endothelium was also hydrodissected from the limbus using trypan blue to stain the Descemet's membrane. Continuous curvilinear descemetorhexis (CCD) was performed to remove a circular section of the Descemet's membrane using a 27 gauge cystotome. Donor tissue was inserted into the anterior chamber through a 5 mm limbal incision and apposed to the host stroma. Polymers were removed following transplantation. Similar surgical procedures were performed in both rabbits and eyebank eyes. Haematoxylin eosin stains were performed after 28 days in rabbits, and eyebank eyes were fixed immediately following surgery for endothelial cell counts. RESULTS: Rabbit control eyes demonstrated stromal oedema caused by loss of Descemet's membrane, whereas transplanted eyes had clear corneas. The mean (standard deviation) pachymetry of operated eyes was 376.6 (SD 32.5) mum compared with 389.6 (SD 25.1) mum in the unoperated eye. Mean endothelial density immediately following surgery in eyebank eyes was 2749 (SD 288) cells/mm(2). CONCLUSIONS: Transplantation of Descemet's membrane by CCD produces a functional graft with an optically clear interface similar to control cornea.

Animals↗

Hepatic glycogen breakdown is implicated in the maintenance of plasma mannose concentration.

D-mannose is an essential monosaccharide constituent of glycoproteins and glycolipids. However, it is unknown how plasma mannose is supplied. The aim of this study was to explore the source of plasma mannose. Oral administration of glucose resulted in a significant decrease of plasma mannose concentration after 20 min in fasted normal rats. However, in fasted type 2 diabetes model rats, plasma mannose concentrations that were higher compared with normal rats did not change after the administration of glucose. When insulin was administered intravenously to fed rats, it took longer for plasma mannose concentrations to decrease significantly in diabetic rats than in normal rats (20 and 5 min, respectively). Intravenous administration of epinephrine to fed normal rats increased the plasma mannose concentration, but this effect was negated by fasting or by administration of a glycogen phosphorylase inhibitor. Epinephrine increased mannose output from the perfused liver of fed rats, but this effect was negated in the presence of a glucose-6-phosphatase inhibitor. Epinephrine also increased the hepatic levels of hexose 6-phosphates, including mannose 6-phosphate. When either lactate alone or lactate plus alanine were administered as gluconeogenic substrates to fasted rats, the concentration of plasma mannose did not increase. When lactate was used to perfuse the liver of fasted rats, a decrease, rather than an increase, in mannose output was observed. These findings indicate that hepatic glycogen is a source of plasma mannose.

Administration, Oral↗

Phase I trial of concurrent chemoradiotherapy with docetaxel, cisplatin and 5-fluorouracil (TPF) in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN).

The aim of this study was to evaluate the efficacy and toxicity of a concurrent chemoradiotherapy using docetaxel, cisplatin and 5-fluorouracil (5-FU) (TPF) in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN). In total, 19 patients with previously untreated stage III-IV SCCHN were entered onto this trial. Patients received two cycles of chemotherapy. Cycles were repeated every 4 weeks. The starting doses (dose level 1) were docetaxel 60 mg m(-2), cisplatin 70 mg m(-2), and 5-day continuous infusion of 5-FU 600 mg m(-2) day(-1). Radiation was targeted to begin on the first day of chemotherapy, day 1. The total radiation dose to the primary tumour site and neck lymph nodes was between 63.0 and 74.0 Gy. At least three patients were examined at each dose level before advancing to the next level. The maximum-tolerated dose (MTD) of this regimen was docetaxel 60 mg m(-2), cisplatin 60 mg m(-2) and 5-FU 600 mg m(-2) day(-1). The main toxicities were mucositis (grade 3 and 4, 79%), leukocytopenia (grade 3 and 4, 53%), neutropenia (grade 3 and 4, 42%), anaemia (grade 3, 16%), liver dysfunction (grade 3, 11%) and renal dysfunction (grade 2, 11%). The overall response rate was 100%, including 84% complete responses (CRs). This concurrent chemoradiotherapy with TPF was safe and well tolerated. The high CR rate justifies further evaluation of this chemoradiotherapy modality in advanced SCCHN patients.

Aged↗

Real-time monitoring for detecting rejection using strain gauge force transducers in porcine small bowel transplantation.

PURPOSE: The clinical results of small bowel transplantation (SBT) have not been satisfactory mainly because of the immunological barrier. It is important to detect the presence of and to perform adequate treatment of rejection as early as possible to improve graft survival. Therefore, we have established a pig model to monitor graft motility as a means to detect rejection in real time. METHODS: Orthotropic SBT was performed in 25 pigs using FK-506 (0.05 to 0.1 mg/kg/d) immunosuppression. The interdigestive motor patterns were evaluated using strain gauge force transducers (SG). Seven pigs without SBT were treated as controls (C). Animals that displayed migrating motor complex (MMC) activity as evidenced by duration, amplitude, and interval in the graft were alive more than 10 days with adequate oral feeding: the functional graft (FG) group. In contrast the rejection (R) group did not show these activities on data recorded within 10 days before death due to rejection. RESULTS: The FG group showed MMC propagated throughout the graft with all parameters almost the same as the control group except for the duration. In contrast, all parameters in the group R were significantly lower than those in group FG, suggesting that group R motility was obviously impaired by rejection. CONCLUSIONS: The SG method may afford real-time monitoring of transplanted bowel motility that could be useful to detect rejection after SBT.

Animals↗

Immunosuppressive effect of nucleoside-nucleotide-free diet in rat allogeneic small intestinal transplantation.

BACKGROUND: We evaluated the effects of nucleosides (NS) and nucleotides (NT) on the rejection of rat allogeneic small intestinal transplants. METHODS: A 2-cm segment of jejunum from fetal Fischer rats (RT-1(lvl)) was transplanted at day 19 of gestation into the abdominal wall of 7-week-old Lewis rats (RT-1(l)) by a nonvascular technique. Two weeks before transplantation, recipient rats were separated into an NS-NT-free group and an NS-NT-supplemented group. At 2 days after transplantation, histologic study of the grafts was performed with hematoxylin-eosin staining and interleukin-2 (IL-2) production estimated in recipient blood using an ELISA method. The morphologic findings were graded in a blind fashion on a scale of 0 to 4, with 0 indicating an intact intestinal structure. RESULTS: Mean plasma IL-2 levels of the NS-NT-free group were significantly lower than those of the NS-NT-supplemented group. The mean rejection score of the NS-NT-free group was also significantly lower than that of the NS-NT-supplemented group. CONCLUSIONS: Administration of an NS-NT-free diet reduces acute rejection in rat small intestinal transplantations.

Animals↗

Pyridoxal-aminoguanidine adduct is more effective than aminoguanidine in preventing neuropathy and cataract in diabetic rats.

We examined the ability of a pyridoxal-aminoguanidine adduct with both antiglycation and antioxidant activities in vitro to protect against neuropathy and cataract in streptozotocin-diabetic rats and compared the result with that of aminoguanidine. In vivo antiglycation and antioxidant activities were also compared between the adduct and aminoguanidine. Diabetic rats were given either of the compounds in their drinking water (9 mM) for 7 weeks. Neither compound affected body weight, blood glucose level or urine volume. The adduct, but not aminoguanidine, significantly improved motor nerve conduction velocity. The time to develop cataract was longer in adduct-treated rats than in untreated and aminoguanidine-treated rats. The increase in opacification of lenses in culture medium containing high glucose levels (55.5 mM) was more efficiently attenuated by the adduct than by aminoguanidine. Adduct and aminoguanidine similarly lowered glycated hemoglobin levels. The level of urinary 8-hydroxy-2'-deoxyguanosine, a marker of oxidative DNA damage, and the level of liver malondialdehyde plus 4-hydroxy-2-alkenals, a marker of tissue lipid peroxidation, both of which were elevated by diabetes, were significantly reduced by the adduct but not by aminoguanidine. These findings indicate that the pyridoxal-aminoguanidine adduct is superior to aminoguanidine in preventing diabetic neuropathy and cataracts, and we suggest that this may be at least partly due to the higher antioxidant activity of the former.

8-Hydroxy-2'-Deoxyguanosine↗

Clinicopathological study of vesicoureteral reflux (VUR)-associated pyelonephritis in renal transplantation.

We retrospectively studied the occurrence of vesicoureteral reflux (VUR)-associated pyelonephritis using renal biopsies obtained from the transplanted kidneys, and correlated the histological changes with clinical parameters. Out of a total of 131 renal biopsies performed between 1990 and 2001 on renal transplant patients at the department of Urology of Nagasaki University Graduate School of Biomedical Sciences, 12 patients showed pyuria more than twice in a single year. Seven of these 12 patients were available for determining VUR by voiding cystourethrography (VCUG). Cystoureterography demonstrated VUR in three of seven studied patients with pyuria. A histopathological examination revealed dilatation of both proximal and distal tubules in renal biopsies of transplant patients with VUR, compared to renal biopsies of transplant patients without VUR, or non-transplanted patients with thin membrane disease. One of the patients with VUR showed advanced features of chronic pyelonephritis in four consecutive biopsies at different time points, suggesting a late stage of reflux nephropathy in the transplanted kidney. We conclude from our study that the occurrence of VUR-related pyelonephritis may be one of the important long-term complications in the survival of renal allografts.

Adult↗

Different clinicopathological courses of two recipients of kidneys retrieved from the same non-heart beating donor.

We report the clinicopathological courses of two recipients of kidneys retrieved from the same non-heart beating donor (NHBD). A 52-year-old man received a renal transplant from an NHBD. The donor was a 66-year-old woman who died of subarachnoid haemorrhage. The recipient was immunosuppressed by basiliximab, tacrolimus (TAC), mycophenolate mofetil (MMF), methyl prednisolone (MP), and antilymphocyte globulin (ALG). On post-operative day (POD) 21, haemodialysis therapy was withdrawn, however, their serum creatinine (s-Cr) level failed to improve. Four transplant biopsies were performed (1 h and POD 46, 74, and 114). The biopsy showed tubular degeneration but no evidence of TAC nephrotoxicity. The last biopsy after discontinuation of TAC demonstrated acute rejection of borderline grade. The s-Cr level at discharge was 5.0 mg/dL. The contra-lateral kidney was transplanted into a 31-year-old female and showed early functioning, with an s-Cr level at discharge of 1.8 mg/dL. Biopsy examination on POD 38 showed a recovery of tubular degeneration. The causes of delayed graft function and persistently high level of s-Cr in Case 1 remain unclear. Various factors, including donor-related factors, recipient-related factors, TAC nephrotoxicity, acute rejection, and urinary tract infection could all be associated with this condition.

Adult↗

Universal distribution of c-kit-positive cells in different types of Hirschsprung's disease.

Interstitial cells of Cajal (ICCs) have been reported to play the role of a pacemaker in regulating bowel motility. The relationship between neurons and ICCs, however, remains unclear. Hirschsprung's disease (HD) is an ideal model for investigating this relationship. The operated specimens obtained from 6 short and 3 long segment aganglionosis patients and 3 controls were used as the subject materials in this study. ICCs were immunohistochemically identified using a specific antiserum c-kit, a tyrosine kinase receptor expressing ICCs. Nitrergic nerves were demonstrated by NADPH-diaphorase (NADPH-d) histochemistry. C-kit immunohistochemistry was also combined with protein gene product 9.5 (PGP 9.5; as a general neuronal marker). In the normoganglionic segment of HD, numerous c-kit-positive cells and NADPH-d positive neurons were found in the proper muscle layer, including Auerbach's plexus. In the oligoganglionic segment, the number of c-kit-positive cells and NADPH-d neurons slightly decreased. In the inner border of the circular muscle layer (IBCM), the c-kit-positive cell networks and NADPH-d activities remained in short segment cases, while both of them were absent in the long segment cases. In the aganglionic segment, c-kit positive cells were present universally but the number of them was slightly decreased in the proper muscle layer. The c-kit-positive cell networks of IBCM were seen where extrinsic neurons were present, while they were almost completely absent where extrinsic neurons were absent in the proximal zone of the long segment cases. C-kit positive cells were present universally in the oligoganglionic as well as aganglionic segments of HD. The distribution and properties of c-kit positive cells were related to the presence of extrinsic neurons in aganglionic segment. Based on these findings, aperistalsis is considered not to relate with c-kit positive cells, and c-kit positive cells are not supposed to have a neurogenic origin and can develop without neurons, however the lack of enteric neurons may influence the full differentiation of ICCs.

Child↗

Effects of omega-3 fatty acids in rat allogenic small intestinal transplantation.

The aim of this study was to estimate the effect of omega-3 fatty acids on the recipient and graft immune response after rat allogenic small intestinal transplantation. Seven-week-old Lewis rats were randomly assigned to one of three groups according to the diet received: an FO group (fish oil supplemented), an SB group (soy bean oil supplemented) or a control group (normal rat chow). The recipient Lewis rats were each given their respective group diet for 12 days, and then, on the 19th day of gestation, a 2 cm jejunum from the donor fetal Fischer rat was transplanted into the abdominal wall of the recipient rats using a non-vascular anastomotic technique. The recipient rats were killed on day 2 after transplantation, and the recipient plasma IL-2, IFN-gamma and IL-1 beta levels were determined. In addition, the histological findings of the graft were analyzed. The cytokine levels of the FO group were significantly lower than the other two groups. In order to determine the grade of rejection, the morphological findings were blindly graded on a scale of 0-4. The mean grade of the FO group was also significantly lower than the other two groups. Omega-3 fatty acids are therefore considered to have an immunosuppressive effect on rat allogenic small intestinal transplantation based on the recipient plasma IL-1 beta, TNF and IL-2 levels and the histological findings of the grafts.

Animals↗

Association of genetic polymorphisms in CYP19 and CYP1A1 with the oestrogen receptor-positive breast cancer risk.

Since tamoxifen has been shown to reduce the risk of oestrogen receptor (ER)-positive, but not ER-negative, breast cancers in a chemoprevention trial (P-1), it is important to develop assays to assess risk factors for ER-positive breast cancer in order to appropriately select candidates for chemoprevention with tamoxifen. Thus, the significance of genetic polymorphisms of genes involved in oestrogen biosynthesis (CYP19) and metabolism (CYP1A1) as a risk factor for ER-positive breast cancers was evaluated. A case-control study was conducted with 257 breast cancer patients and 191 healthy female controls. Two polymorphisms, CYP19 (TTTA repeats) in intron 4 and CYP1A1 6235C/T in the 3' non-coding region, and their association with the breast cancer risk after adjustment for the other epidemiological risk factors were examined. CYP19 (TTTA)7(-3bp) allele carriers showed a significantly (P<0.05) increased risk of ER-positive breast cancers (Odds Ratio (OR)=1.72, 95% Confidence Interval (CI) 1.10-2.69), but not ER-negative breast cancers. CYP1A1 6235C allele carriers showed a non-significant (P=0.06) trend towards a decreased risk of ER-positive breast cancers (OR=0.65, 95% CI 0.42-1.02), but not ER-negative breast cancers. The combination of these two polymorphisms was found to be more useful in the assessment of the ER-positive breast cancer risk (OR=3.00, 95% CI=1.56-5.74) than the CYP19 (TTTA)7(-3bp) polymorphism alone. The combination of CYP19 (TTTA)7(-3bp) and CYP1A1 6235C/T polymorphisms is associated with an ER-positive, but not ER-negative, breast cancer risk, and, thus, would be useful in the selection of candidates for chemoprevention with tamoxifen.

Adult↗

Costimulatory signals distinctively affect CD20- and B-cell-antigen-receptor-mediated apoptosis in Burkitt's lymphoma/leukemia cells.

CD20 is a B-cell differentiation antigen and known to induce apoptosis in Burkitt's lymphoma/leukemia (BL) cells upon antibody-mediated crosslinking. We examined the biological effect of CD20 crosslinking on BL cell lines and observed that apoptosis induction is accompanied by activation of multiple caspases, including caspase-8, -9, -3, -2, and -7. Further investigation revealed a clear synergism between apoptosis mediated by CD20 and by B-cell antigen receptor (BCR). Examination of the effect of simultaneous crosslinking of other cell surface molecules with crosslinking of CD20 or BCR on apoptosis induction showed that these molecules had either a synergistic or inhibitory effect on induction of apoptosis. It is worth noting that some molecules had a different effect on CD20- and BCR-mediated apoptosis. Simultaneous crosslinking of the molecules CD10, CD22, CD72, and CD80 inhibited BCR-mediated apoptosis, but enhanced CD20-mediated apoptosis. Further studies revealed that regulation of CD20-induced apoptosis by other costimulatory molecules is achieved by modification of caspase activation. CD20-mediated apoptosis in BL cells may provide not only a model for understanding the mechanism regulating clonal selection of B cells but a new therapeutic strategy for BL patients.

Annexin A5↗

Stochastic heating and acceleration of electrons in colliding laser fields in plasma.

We propose a mechanism that leads to efficient acceleration of electrons in plasma by two counterpropagating laser pulses. It is triggered by stochastic motion of electrons when the laser fields exceed some threshold amplitudes, as found in single-electron dynamics. It is further confirmed in particle-in-cell simulations. In vacuum or tenuous plasma, electron acceleration in the case with two colliding laser pulses can be much more efficient than with one laser pulse only. In plasma at moderate densities, such as a few percent of the critical density, the amplitude of the Raman-backscattered wave is high enough to serve as the second counterpropagating pulse to trigger the electron stochastic motion. As a result, even with one intense laser pulse only, electrons can be heated up to a temperature much higher than the corresponding laser ponderomotive potential.

Journal Article↗