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Y Sugawara

Publications and source records attributed to Y Sugawara.

At least 37 records · Page 2Linked to original sources
PubMed2004

Prediction of hepatic artery thrombosis by protocol Doppler ultrasonography in pediatric living donor liver transplantation.

Hepatic arterial thrombosis (HAT) after liver transplantation is a life-threatening event. Previous reports have suggested that the resistive index (RI) of the hepatic artery predicts HAT. Doppler ultrasonography (US) to measure RI, however, is not routinely performed. The subjects were 70 pediatric patients who underwent living donor liver transplantation (LDLT). Protocol Doppler US was performed once or twice a day for 2 weeks postoperatively and 692 records were examined. Changes in RI values were examined separately in patients with and without HAT complications. The incidence of HAT was 10% (seven of 70). HAT was diagnosed an average of 6.2 days after LDLT. In patients without HAT complications ( n = 63), average RI levels at 14 days after LDLT were 0.71 +/- 0.1 (records, n = 625). In patients with HAT complications, RI decreased gradually within 2 days before the onset of HAT. RI values of less than 0.6 predicted HAT within 2 days before onset, with 83% sensitivity and 85% specificity. RI during the first 2 weeks after LDLT is a sensitive predictor for HAT. Thrombectomy and reanastomosis should be considered when RI values are less than 0.6 in Doppler US.

Adolescent↗
PubMed2004

Spatial and temporal expression of the ventral pelvic skin aquaporins during metamorphosis of the tree frog, Hyla japonica.

Most adult anurans absorb water through their ventral skin to maintain the proper water balance. We examined spatial and temporal expression of frog (Hyla japonica) aquaporins, Hyla AQP-h2 and AQP-h3 proteins, in the ventral pelvic skin by using specific antibodies. Immunofluorescence indicates that AQP-h2 and AQP-h3 first appear in the granular cells of the pelvic skin of the tadpoles at Gosner stage 42, and such labeling is seen in later stages as well. These findings were confirmed by Western blot analysis. In addition, Northern blot analysis demonstrated that V2-type vasotocin (AVT)-receptor mRNA is first expressed at the same stage as are the AQP proteins, which suggests a functional relationship between expression of AQP proteins and AVT receptor. Also, AQP expression in the ventral pelvic skin is consistent with the morphological changes that occur in the skin for adaptation from life in water to that on land.

Animals↗
PubMed2004

Living donor liver transplantation for end-stage hepatitis C.

Living donor liver transplantation is important for patients with end-stage viral hepatitis because of the shortage of organs from deceased donors. However, preliminary results indicate that living liver donation might be disadvantageous for hepatitis C virus-positive patients. Twenty-seven patients who underwent living donor liver transplantation for hepatitis C virus cirrhosis preemptively received antiviral therapy using interferon-alpha2b and ribavirin, which was started an average of 32 days after the operation and continued for at least 6 months thereafter. The serum hepatitis C virus RNA became negative in the 8 of 16 patients with more than 1 year follow-up. The cumulative 3-year patient survival was 85%, which was comparable to that of hepatitis C virus negative patients (n = 93; 90%). Preemptive antiviral therapy after transplantation may be necessary for satisfactory results after living donor liver transplantation.

Adult↗
PubMed2004

Effect of hematocrit on pharmacokinetics of tacrolimus in adult living donor liver transplant recipients.

OBJECTIVE: Plasma drug concentrations are generally considered to reflect efficacy and pharmacokinetics more directly than those in whole blood. However, whole blood has been selected as the matrix to monitor concentrations of tacrolimus (FK506), because it is difficult to accurately measure plasma FK506 concentrations. Because FK506 highly and saturably binds in blood cells, a change in hematocrit value (Hct) may affect FK506 pharmacokinetics. Therefore, we investigated effects of Hct on FK506 pharmacokinetics. METHODS: First, we analyzed data on FK506 distribution among human blood cells in vitro. Briefly, we employed an equation, which describes saturable binding of FK506 to blood cells, and simulated plasma FK506 concentrations and clearances using the above equation with respect to a variable Hct. Subsequently, we retrospectively analyzed dosages and whole blood FK506 concentrations to predict plasma FK506 concentrations in living donor transplant recipients. RESULTS: In the simulation study, the Hct changed plasma FK506 concentrations and clearances based in whole blood. In living donor liver transplant recipients, whole blood FK506 concentrations were maintained within a therapeutic range, while the Hct varied after transplantation. The correlation of Hct with the ratio of dose/trough concentrations of FK506 (D/C) in plasma (D/Cp) (R = -0.23, n = 343) was weaker than that for D/C in whole blood (D/CWB) (R = -0.53, n = 343). CONCLUSION: Hct may be an important factor affecting the pharmacokinetics of FK506 in living donor liver transplantation recipients. It may be necessary to take Hct into consideration in the FK506 dosing regimen, especially when the Hct is low.

Adult↗
PubMed2004

Classification of portal vein anatomy for partial liver transplantation.

The anatomy of the portal vein is usually classified as 3 to 5 patterns and simple compared with the anatomy of the hepatic artery. The variety of portal vein anatomy was examined in 287 living donors for liver transplantation. More than 90% of donors showed a normal bifurcation type; 6% showed the trifurcation type. Only 3% displayed a separate origin of the right paramedian and the right lateral branches. There was no anomalous pattern that had not been reported previously. In our series, we conclude that it is rare for 2 or more stumps of portal vein to appear in partial liver transplantation. The frequency is much less if the left liver or the right lateral liver graft is used for adult-to-adult living donor liver transplantation.

Functional Laterality↗
PubMed2004

Simultaneous hepatic artery and portal vein thrombosis after living donor liver transplantation.

Simultaneous hepatic artery and portal vein thrombosis rarely occurs after liver transplantation. The etiology is unknown. Of 213 patients (72 children and 141 adults) that underwent living donor liver transplantation (LDLT) from January 1996 to March 2003, 4 (2%) developed simultaneous thrombosis at 3 hours to 7 days (median, 4 days) after the operation. Emergent thrombectomy was performed in three patients; the remaining patient was registered in the Japan organ transplant network. All of the patients died due to hepatic failure (range, 18 hours to 6 days after the diagnosis; median, 2 days). Portal vein, hepatic artery, and hepatic vein velocity in the liver graft were measured every 12 hours by Doppler ultrasonography for 2 weeks after liver transplantation. These parameters were stable until just before the simultaneous thrombosis. These findings indicate that protocol Doppler ultrasonography can diagnose, but not predict, this fatal complication.

Adolescent↗
PubMed2004

Conversion to cyclosporine provides valuable rescue therapy for living donor adult liver transplant patients intolerant to tacrolimus: A single-center experience at the University of Tokyo.

Tacrolimus-based immunosuppression is currently accepted as mainstream therapy in many transplant centers worldwide due to its potent immunosuppressive activity compared to cyclosporine. A tacrolimus-based regimen has been successfully used for our living donor liver transplantation (LDLT) recipients. Adverse effects such as neurotoxicity, nephrotoxicity, and new-onset diabetes mellitus, however, have limited its clinical application. In deceased donor liver transplantation, cyclosporine rescue therapy is valuable for such complications, but few reports have described a strategy for conversion in LDLT. Herein, we present our experience of conversion from tacrolimus to cyclosporine therapy in adult LDLT recipients. Among 203 recipients, 37 patients (18%) required conversion, primarily for neurotoxicity (41%), diabetes mellitus (16%), hematopoietic disorder (16%), and gastrointestinal intolerance (11%). Primary adverse events resolved within 2 months after conversion in 35/37 (94%) of the patients. For LDLT recipients unable to maintain effective immunosuppression with tacrolimus, conversion to cyclosporine is an effective option.

Adult↗
PubMed2004

Tracheoesophageal fistula secondary to chemotherapy for malignant B-cell lymphoma of the thyroid: successful surgical treatment with jejunal interposition and mesenteric patch.

We report a case of tracheoesophageal fistula (TEF) secondary to chemotherapy for primary thyroid lymphoma. A 65-year-old man with a short history of a rapidly enlarging neck mass was diagnosed as having thyroid lymphoma of diffuse, large B-cell type. The TEF occurred during the first course of chemotherapy including cyclophosphamide, doxorubicin, vincristine and prednisolone. After placing a feeding gastrostomy without oral intake, eight cycles of chemotherapy were completed and complete remission was achieved. Although the cervical mass disappeared, TEF and esophageal stenosis persisted. Total thyroidectomy and resection of the stenotic cervical esophagus were carried out followed by interposition of the revascularized jejunum and its mesenteric patch to cover the TEF. This seems to be the first report of a TEF caused by chemotherapy for primary thyroid B-cell lymphoma. A variety of treatments for TEF including simple closure, tracheal resection, colonic bypass and muscle flap have been reported with low success rates. Our procedure using a jejunal mesenteric patch seems to be unique and may be a new treatment strategy for TEF.

Aged↗
PubMed2004

[Induction chemotherapy and radical resection for primary nonseminomatous mediastinal germ cell tumor (NSGCT); report of a case].

A 15-year-old male was admitted to our hospital for treatment of an anterior mediastinal tumor. The tumor was visualized by chest radiography 3 months prior to admission. Computed tomography (CT) revealed a heterogeneous solid tumor located in the anterior mediastinum. Although CT-guided needle biopsy had been performed twice, histologic diagnosis could not be confirmed. We believed this tumor to be nonseminomatous mediastinal germ cell tumor (NSGCT) and started intensive chemotherapy with cisplatin (CDDP) without histologic diagnosis because his serum AFP level was rapidly increasing. After 2 courses of chemotherapy, his serum AFP level returned to the normal range and surgical resection of the tumor with part of right lung was performed. Histopathological examination revealed that the tumor consisted of mature teratoma and yolk sac tumor. He underwent 1 course of chemotherapy post-operatively because a small number of viable cells were histopathologically recognized in the yolk sac component. At the time of writing, the patient is alive without any evidence of recurrence.

Adolescent↗
PubMed2003

Rescue of shoot apical meristems of chrysanthemum by culturing on root tips.

A new method to regenerate plants from leaf primordia-free shoot apical meristem domes (LP-free SAMs) was developed by establishing the meristem dome on the cut surface of root tips. Ten days after culture, the viable rate of LP-free SAMs of chrysanthemum 'Piato' attached to chrysanthemum root tips was >40%. Shoot regeneration was not observed from LP-free SAMs without the root tips. When LP-free SAMs of chrysanthemum were transferred to root tips of either petunia, cabbage, or carnation, the highest shoot regeneration rate was observed with cabbage root tips. Microscopic observation documented that the LP-free SAM temporarily adhered to the cut surface of the root tip of cabbage.

Botany↗
PubMed2003

Duct-to-duct biliary reconstruction for living donor liver transplantation: experience of 92 cases.

Bile duct-to duct reconstruction is now performed in living donor liver transplantation (LDLT) for adult patients. To confirm the feasibility, the results after the reconstruction were retrospectively analyzed. The subjects were 92 adult patients who underwent LDLT at the University of Tokyo Hospital. During the observation period (median 546 days), biliary complications were observed in 28 cases (30%). The complications included bile juice leakage in 11, stenosis at the anastomotic site in 9, and tube trouble in 8. Of these, 20 patients required surgical revision. The results suggest that duct-to-duct reconstruction provides satisfactory results, although long-term observation will be necessary.

Bile Ducts↗
PubMed2003

Left liver grafts for patients with MELD score of less than 15.

Left liver grafts are now seldom used for adult recipients of living donor liver transplantations because the left liver is believed to be insufficient to meet patient metabolic demands. At the University of Tokyo Hospital, left liver grafts have been limited to patients with fulminant hepatic failure or chronic hepatic failure with a model for end-stage liver disease (MELD) score of less than 15. Since 2000 25 adult patients received left liver grafts. The mean graft weight to standard liver volume ratio was 44%. The rates of acute rejection, vascular, and biliary complications were 24%, 0%, and 25%, respectively. All patients survived the operation and are doing well with a mean follow-up of 17 months. The present results suggest that left liver grafts provide acceptable results among patients satisfying our criteria.

Adult↗
PubMed2003

Disturbance of neural respiratory control in neonatal mice lacking GABA synthesizing enzyme 67-kDa isoform of glutamic acid decarboxylase.

To examine the role of GABA in the respiratory rhythm and pattern generation in neonatal mice, we analyzed the function of the respiratory control system of 67-kDa isoform of glutamic acid decarboxylase (GAD67)-deficient neonatal mice. In these mutant (GAD67-/-) mice, GABA levels in the brainstem were reduced to about 30% of those in wild-type (GAD67+/+) mice. In in vivo preparations, ventilatory parameters were analyzed by whole body plethysmography and electromyography of intercostal muscles. GAD67-/- mice exhibited abnormal respiratory patterns, i.e. irregular respiratory rhythm, and periodic gasp-like respiration followed by shallow breathing with short inspiratory duration and apnea. In in vitro GAD67-/- brainstem-spinal cord preparations, inspiratory C4 burst duration was shorter than that in GAD67+/+ preparations. Whole cell recordings revealed that activities of inspiratory neurons in the ventral medulla of GAD67-/- mice were characterized by a short depolarization period and a paucity of firing during the inspiratory phase. Superfusion of the in vitro GAD67-/- preparation with 10 microM GABA prolonged C4 burst duration and partly restored a normal pattern of inspiration, although the restoration was limited. These results indicate that reduced GABA levels during the perinatal period induce malfunction in the respiratory control system. We suggest that GABAergic transmission is not essential for basic respiratory rhythm generation but plays an important role in the maintenance of regular respiratory rhythm and normal inspiratory pattern in neonatal mice.

Animals↗