Takeji Uno

Effect of protease inhibitor on ischemia/reperfusion injury of the rat liver.

The purposes of this study were to clarify the role of neutrophilic proteases in the pathogenesis of hepatic ischemia/reperfusion injury and to determine whether urinary trypsin inhibitor (UTI) pretreatment attenuated liver ischemia/reperfusion injury in rats. Livers from male Sprague-Dawley rats were subjected to 90 min of no-flow warm ischemia followed by 120 min of reper-fusion. Rats were divided into a UTI group and a control group. In the control group, 120-min reperfusion of the liver produced a significant increase in myeloperoxidase activity, a significant decrease in ATP and energy charge, and a marked increase in the serum aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase levels. In the UTI group, the myeloper-oxidase activity was significantly attenuated (i><0.01), ATP and energy charge were significantly improved (P<0.01 and P<0.05, respectively), and the elevation in serum aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase was also markedly suppressed (P<0.05, P<0.01, and P<0.05, respectively) compared with the control group. Sections through the livers of control rats showed severe hepatocyte necrosis with neutrophil infiltration. In the UTI group, there was slight congestion and hepatocyte necrosis. The survival rate after 90-min liver ischemia was significantly improved compared with that in the control group (P<0.05). The results of this study suggest that pretreatment with UTI significantly attenuates liver reperfusion injury, perhaps by inhibiting neutrophil proteases.

PHARMACOKINETIC ADVANTAGES OF A NEWLY DEVELOPED TACROLIMUS OIL-IN-WATER-TYPE EMULSION VIA THE ENTERAL ROUTE

We developed an oleic acid oil-in-water (o/w)-type emulsion of a new tacrolimus formulation that presented an improvement in the delivery of the drug for oral absorption. This investigation was undertaken to assess a sustained release drug delivery system and selective drug transfer into the lymphatic system. The whole blood concentration profiles after oral administration at a dose of 2mg/kg and bone marrow, spleen, liver, lung, small intestine, kidney, brain, and whole blood distribution after oral administration at a dose of 1 mg/kg of o/w emulsion formulation of tacrolimus (O/W group) were compared with those of commercially available formulation (T group) in the rat. The mean diameter of the o/w emulsion droplets was 0.47 μm immediately after preparation. The tacrolimus entrapping efficiency of o/w emulsion was 71.3+5.0% in 12 h and did not change for 2 d. The area under the whole blood concentration-time curve (AUC) in the O/W group was significantly higher (P<0.01) than that in the I group. In contrast, the values of constant elimination rate and total clearance in the O/W group were significantly lower (P<0.01) than those in the T group, with a comparative bioavailability of 115.9%. The tissue concentration of tacrolimus in the O/W group was significantly higher levels in the bone marrow, spleen, liver, lung, and small intestine, and significantly lower in the brain and kidney, relative to the T group. The o/w emulsion of tacrolimus may be an improved dosage form via the enteral route.

The Pharmacokinetics of Water-in-Oil-in-Water-Type Multiple Emulsion of a New Tacrolimus Formulation

We developed a water-in-oil-in-water (W/O/W)-type multiple emulsion of a new tacrolimus formulation. A potential approach to avoid the complications of systemic immunosuppression and simultaneously enhance immunosuppressive efficacy is to deliver immunosuppressive agents locally to the site of the target organs. The W/O/W emulsion is dispersed oil drops containing smaller water droplets that allow the delivery of drugs preferentially to the reticuloendothelial system (RES). Since the liver and the spleen are primary components of the RES, and the brain and the kidney have a poor RES, we hypothesized that a W/O/W emulsion of tacrolimus would prossess the pharmacokinetic benefits of local immunosuppression. We evaluated this hypothesis in a rat model. The tacrolimus levels of whole blood, the liver, spleen, brain, and kidney in rats given intravenous emulsions of tacrolimus (W/O/W group) were compared with a group administered tacrolimus alone (T group). There were no significant differences between the pharmacokinetic parameters of W/O/W group and T group based on whole blood data. However, the W/O/W group had significantly decreased tacrolimus levels in the brain and kidney, and significantly increased levels in the liver and spleen compared with the T group. These data suggest that the W/O/W emulsion is applicable as an intravenous drug carrier for local immunosuppression.

Pharmacokinetic and immunosuppressive effects of tacrolimus-loaded biodegradable microspheres

The objective of this study was to characterize the pharmacokinetics and immunosuppression of a tacrolimus‐loaded biodegradable microsphere (TLBM) in rats. We prepared TLBM. DA/Slc rats were given TLBM at a dose of 1.6 mg/kg (n = 9), 2.4 mg/kg (n = 5), or 7.2 mg/kg (n = 7) tacrolimus contents by a single subcutaneous administration to achieve sustained release over a long period. DA/Slc rats were given TLBM by a single subcutaneous administration at a dose of 4.8 mg/kg (n = 6) tacrolimus contents to clarify the main site of TLBM uptake in the organs. In the rat liver transplantation model, the recipients were given TLBM at a dose of 0.16 mg/kg (n = 5), 2.4 mg/kg (n = 4), or 4.8 mg/kg (n = 5) tacrolimus contents by a single subcutaneous administration on the first day after operation. Overall survival days were compared. Continuous flat parallel concentration profiles were significant for 10 days from the first day after a single subcutaneous administration of TLBM (P < .01). The relationship between the dosages of TLBM administration and area under the concentration–time curve (AUC) up to 18 days demonstrated a linear regression line (P < .01). In addition, the relationship between the dose of TLBM and the survival days of the recipients in the liver transplantation model showed a positive correlation. The current pharmacokinetic study of TLBM revealed significantly increased tacrolimus levels in the regional lymph nodes compared with other organs except bone marrow (P < ..01). In conclusion, TLBM allowed tacrolimus to release gradually in a very stable manner for 10 days, with dose‐dependent immunosuppression after a single subcutaneous administration. The main site of TLBM uptake after subcutaneous administration was the regional lymph node of administration site. (Liver Transpl 2004;10:392–396.)

Ultrasonic Exploration of Contralateral Side in Pediatric Patients with Inguinal Hernia

The width of low echoic region at the internal ring (WLIR) of an inguinal canal demonstrated by ultrasonography was applied in the preoperative diagnosis of the contralateral side in pediatric patients with inguinal hernia. The ultrasonic diagnosis of 39 pediatric patients with inguinal hernia and 38 children without inguinal hernia under 15 years of age were conducted at Hamamatsu University Hospital from April 1988 to January 1989. The WLIR of children without inguinal hernia were within 6 mm in boys under 15 years of age and within 3 mm in girls under 5 years of age. There were no statistically significant differences between the WLIR of the right side and that of the left side, and the WLIR of the following three age groups also demonstrated no statistical significance: under 1 year of age, 1 to 5 years of age, 5 to 15 years of age. On the other hand, the WLIR of the hernia side of pediatric patients with inguinal hernia were significantly wider than that of the contralateral side in boys and girls under 5 years of age (P<0.01), as well as in boys 5 to 15 years of age (P<0.05). Therefore, we recommend a contralateral exploration for pediatric patients with inguinal hernia when the WLIR is 7 mm or more in boys under 15 years of age and 4 mm or more in girls under 5 years of age.

Laparoscopic surgery for gonadal dysgenesis in children.

Three pediatric phenotypic females presented with gonadal dysgenesis. Their gonads were removed laparoscopically. These phenotypically normal females, who do not have any intersex problems or ambiguous genitalia, represent a unique group of patients having a Y chromosome or a fragment of it in their genetic constitutions. We performed laparoscopic adnexectomy with Endoloop ligatures or an ultrasonically activated scalpel. No significant complication occurred in any of the cases. Pathologic examination revealed gonadoblastoma in one of the gonads of one patient. We propose that laparoscopic surgery is a safe and minimally invasive procedure for prophylactic gonadectomy to prevent neoplasia, even when performed on pediatric patients.

Investigation of melena and hematochezia as the chief complaint of gastrointestinal bleeding in pediatric surgical patients

The causes of melena or hematochezia in 48 pediatric patients were examined. Malrotation with volvulus was an important cause of hemorrhage during the newborn period, and intussusception was very typical in patients aged from 1 month to 1 year. Polyps of the rectum and colon were the most common causes of melena or hematochezia in patients older than 1 year. No cause of melena or hematochezia could be identified in 11 children. Ten patients have remained in good health with no further episodes of melena or hematochezia. Localized multiple polyps of the rectum with focal carcinoma were detected in only one patient. In general, although no further investigation is required after detection of the cause of bleeding and its successful treatment, it should be kept in mind that gastrointestinal malignancy can occur in children.

A Case of Mixed-type Dysgerminoma with a High Serum Concentration of both Human Chorionic Gonadotropin and α-Fetoprotein in a Child

Dysgerminoma is divided into two types: pure and mixed. The mixed type is related to other various elements of germ cell tumors. We experienced a case of mixed type dysgerminoma with a high serum concentration of both human chorionic gonadotropin and a‐fetoprotein. The patient was a 6 year old girl who was admitted to the Hamamatsu University School of Medicine with an abdominal mass. Laboratory investigations revealed elevated serum a‐fetoprotein and high concentration of serum β‐human chorionic gonadotropin. The tumor originated from the left ovary. The histopathological diagnosis was dysgerminoma. Serum human chorionic gonadotropin and α‐fetoprotein levels were useful markers in monitoring the response to treatment in this patient.