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Biomedical subjects

Akira Okada

Publications and source records attributed to Akira Okada.

At least 55 records · Page 3Linked to original sources
PubMed2002

A pediatric amino acid solution for total parenteral nutrition does not affect liver function test results in neonates.

PURPOSE: We studied the effects of an amino acid mixture used for total parenteral nutrition (TPN) in pediatrics, on the liver function test results (LFTs) of neonates. METHODS: Thirty neonatal surgical patients were randomly divided into three groups according to the dose of amino acids given: group H ( n = 12, 3.45 +/- 0.07 g/kg per day), group M ( n = 8, 2.59 +/- 0.07 g/kg per day), and group L ( n = 10, 1.72 +/- 0.06 g/kg per day). All patients received the same amount of dextrose (average 21.5 g/kg per day) and no lipid. RESULTS: There were no significant differences in LFTs, namely, direct bilirubin, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, alkaline phosphatase, gamma-glutamyl transpeptidase, and total bile acids, among the three groups on the tenth day of TPN. CONCLUSION: These findings indicate that this amino acid solution for pediatrics has no significant effect on LFTs in neonates, even when high doses of amino acids (3.5 g/kg per day) are infused.

Amino Acids↗
PubMed2002

Effects of isolated small bowel transplantation on liver dysfunction caused by intestinal failure and long-term total parenteral nutrition.

It has not been fully determined whether isolated small bowel transplantation (ISBTx) can reverse liver dysfunction caused by intestinal failure requiring long-term total parenteral nutrition (TPN). A boy with congenital microvillus inclusion disease presented with vomiting and severe diarrhea since the first day of life and had been managed by TPN since then. He suffered from catheter-related sepsis several times. At 14 yr of age he developed progressive hepatosplenomegaly with thrombocytopenia and coagulopathy. He underwent ISBTx with an ileal graft from his blood-identical grandmother at the age of 16 yr. Oral feeding was started on the 14th day after ISBTx and gradually increased. TPN was completely withdrawn after 5 months. Liver was palpated 5 cm below the costal margin before ISBTx, while it became non-palpable 5 months after ISBTx. Serum liver enzyme levels and prothrombin time normalized in the 5 months following ISBTx. Liver biopsy showed marked steatosis, slight cholestasis, and mild bridging fibrosis before ISBTx. Although histological examination of liver biopsy revealed complete disappearance of steatosis 7 and 11 months after ISBTx, liver fibrosis remained unchanged. This clinical experience has shown that although steatosis and cholestasis are reversible after successful ISBTx and withdrawal of TPN, liver fibrosis may remain unchanged.

Adolescent↗
PubMed2002

Successful percutaneous transluminal angioplasty for hepatic artery stenosis in an infant undergoing living-related liver transplantation.

A 1-yr-old girl underwent a living-related liver transplant, with reconstruction of hepatic artery of 2 mm in diameter under microscopy. She developed intestinal perforation requiring closure on day 4 post-transplant and suffered from hepatic artery stenosis (HAS) on post-transplant day 9. Conservative therapies, such as intravenous or transluminal administration of anti-coagulants, vasodilators or fluids, were unsuccessful and caused remarkable general edema and multiple arrhythmias as a result of increased preload. On day 15 post-transplant, because flow velocity was remarkably reduced (as shown by Doppler ultrasound) the patient underwent percutaneous transluminal angioplasty (PTA) using a kit for coronary angioplasty. The balloon catheter was inflated [first: 1.5 mm diameter, 4 atmospheric pressure (a.p.) for 30 seconds (s); second: 2.0 mm diameter, 4 a.p. for 30 s; third: 2.5 mm diameter, 10 a.p. for 30 s]. The stenosis was successfully dilated without any complication. The patient has been doing well with normal liver functions for 4 months after PTA. From this experience, PTA can be performed for HAS after liver transplantation, even in an infantile case, with a careful technique and a special device.

Angioplasty, Balloon↗
PubMed2002

Marked hyperbilirubinemia caused by acute cellular rejection combined with preservation injury in an infant undergoing living-related liver transplantation.

Acute cellular rejection (ACR) and preservation injury (PI) are major complications occurring early after liver transplantation (LTx) and sometimes lead to severe graft dysfunction. We herein report an infant who developed marked hyperbilirubinemia as a result of combined ACR and PI in addition to ischemic damage from bleeding, but recovered without re-LTx. In a 1-yr-old-girl undergoing living-related LTx, liver biopsy (LBx) on post-operative day 7 showed ballooning of the hepatocytes, i.e. microvesicular steatosis (30%) and occasional centrolobular necrosis, consistent with mild-to-moderate PI and ACR with a rejection activity index (RAI) of 2.0. Because drainage of an intra-abdominal abscess was performed and a systemic infection was considered severe, the tacrolimus level was decreased and steroids were discontinued. The total bilirubin level started to rise, thereafter, reaching a maximum of 47.6 mg/dL at 1 month after LTx. LBx showed an RAI of 6.0 and steatosis of 10%. With good response to an increase of tacrolimus level and administration of steroid, the total bilirubin level gradually decreased, finally reaching the normal range in 3 months, and LBx showed no steatosis or finding of ACR. From this experience, ACR, if combined with mild-to-moderate PI or other ischemic damage, may lead to severe clinical manifestations after LTx, which, however, could remit with conservative therapy and without re-LTx.

Acute Disease↗
PubMed2002

Living-related liver transplantation for biliary atresia associated with polysplenia syndrome.

This report describes a 1-yr-old boy with biliary atresia (BA) and polysplenia syndrome (PS) who underwent successful living-related liver transplantation (LTx). At the time of initial hepatic portoenterostomy, he was noticed to have a preduodenal portal vein (PV), non-rotation of the intestine, and polysplenia. Because he did not achieve good bile excretion, he underwent a living-related LTx (using a left lateral segment from his mother) at the age of 14 months. Evaluation of the vascular anatomy was made by angiography, magnetic resonance imaging (MRI), computerized tomography (CT), and Doppler ultrasound. The PV was stenotic from the confluence of the superior mesenteric vein (SMV) and splenic vein (SpV) to the hepatic hilum. The retrohepatic inferior vena cava (IVC) was deficient cranially to the renal vein and was connected to the azygous vein. The supra-hepatic IVC was detected below the diaphragm and was connected to three hepatic veins. The common hepatic artery (HA) originated from the superior mesenteric artery. At LTx, the PV was dissected to the level of confluence of the SMV and the SpV, from which the venous graft was interposed using the donor's ovarian vein. Three hepatic veins were plastied into one orifice, which was anastomosed to the graft's hepatic vein under the diaphragm. The graft vascularity and function has been good for 1 yr after LTx. In the present case, sufficient pre-LTx evaluation of vascular anomalies seemed to help performance of the successful LTx.

Abnormalities, Multiple↗
PubMed2002

Role of plasma thrombopoietin level in thrombocytopenia of postoperative biliary atresia patients.

BACKGROUND/PURPOSE: To evaluate if thrombocytopenia may be related to plasma thrombopoietin level (P-TPO) in postoperative biliary atresia (BA). METHODS: Forty-three postoperative BA patients aged 1 to 20 years were included. P-TPO was measured by enzyme immunoassay. P-TPO was compared with platelet counts (Plt), Child's classification, presence of splenomegaly, and liver function tests. RESULTS: P-TPO significantly correlated with Plt, child's classification, serum albumin, and cholinesterase level, respectively. In 4 patients undergoing portal decompression procedure, preoperative and postoperative Plt and P-TPO were 87.5 +/- 69.1 x 10(3) and 50.3 +/- 28.0, 118.8 +/- 62.3 x 10(3)/mm3, and 53.0 +/- 55.0 pg/mL, respectively, without significant difference. In 6 patients undergoing liver transplantation (LTx), Plt and P-TPO after LTx was 157.5 +/- 83.5 x 10(3) and 143.5 +/- 75.2, respectively, which were significantly higher than those before LTx (55.0 +/- 15.6 x 10(3)/mm3 and 53.2 +/- 32.9 pg/mL). CONCLUSION: Thrombocytopenia in postoperative BA may be caused by decreased plasma TPO level in accordance with the severity of liver dysfunction rather than hypersplenism.

Adolescent↗
PubMed2002

Vaginal reconstruction in a patient with rhabdomyosarcoma previously treated by total vaginectomy.

In vaginal rhabdomyosarcoma, because of effectiveness of multiple-agent chemotherapy and brachytherapy, function-preserving treatment without radical surgery has been recently recommended. However, for patients with persistent or recurrent tumors, vaginectomy with or without hysterectomy is appropriate. The authors report experience of successful vaginal reconstruction in a rhabdomyosarcoma patient who had total vaginectomy with preservation of the uterus. Because continuity from the vaginal introitus to the uterus was established, fertility can be expected for this patient.

Child↗
PubMed2002

Follow-up studies of anorectal malformations after posterior sagittal anorectoplasty.

BACKGROUND/PURPOSE: There are few follow-up studies comparing posterior sagittal anorectoplasty (PSARP) with conventional procedures for patients with anorectal malformations (ARM). The authors have examined retrospectively postoperative anorectal function of patients with ARM treated with PSARP compared with those treated with conventional methods. METHODS: Anorectal function in 23 patients with high and intermediate type anorectal malformations (PSARP group), who underwent PSARP more than 4 years previously, were assessed by Kelly's clinical scoring system and objective studies. These results were compared with those in 14 cases (5 high and 9 intermediate type cases; control group), who underwent other conventional surgical procedures. RESULTS: Using Kelly's clinical scoring system, scores of the PSARP group compared with the control group were good in 48% versus 21%, fair in 48% versus 58%, and poor in 4% versus 21%, respectively. Barium enema studies suggested better anorectal sphincteric function in patients with high anorectal malformation in the PSARP group. Magnetic resonance imaging (MRI) studies showed more correct placement of the rectum through the striated muscle complex in the PSARP group at the I-line level. Manometric studies showed no difference in maximum resting pressure, anal canal length, and the incidence of anorectal reflex between the two groups. CONCLUSIONS: The favorable results of MRI and barium enema studies can be explained by direct visualization of the striated muscle complex with the aid of electrical stimulation as well as no harmful effects of amputation of the sphincter muscle in PSARP. However, manometric studies suggest anorectal function in patients with high and intermediate anorectal malformations is limited even after PSARP. Long-term postoperative follow-up with adequate bowel management is required for all patients with high or intermediate anorectal malformation.

Adolescent↗
PubMed2002

Gastroesophageal reflux after repair of congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: Mechanisms of postoperative gastroesophageal reflux (GER) remain unclarified in congenital diaphragmatic hernia (CDH). The aim of this study was to examine clinical features of CDH contributing to GER. METHODS: GER was evaluated as esophageal acid exposure measured with 24-hour pH monitoring at the average age of 1.7 +/- 0.9 months in 26 survivors of CDH. Correlations between the percentage total time pH below 4.0 (reflux index: RI)/number of long acid reflux (long reflux) and clinical features were investigated. The subjects were divided into 2 groups; group A: RI < or = 4.0% (n = 7) and group B: R greater than 4.0% (n = 19). Clinical features were compared between the 2 groups. RESULTS: No significant correlation was noted between RI/long reflux and birth weight, preoperative AaDO2, duration of artificial ventilation, and dimension of the defect. The incidence of direct closure was significantly higher, but use of nitric oxide inhalation and a presence of intrathoracic liver lobe herniation were significantly lower in group B. There was no significant difference of other clinical features indicating the severity of CDH between the 2 groups. CONCLUSION: An association of GER is not rare in early infancy after repair of CDH, which is influenced by the repair methods.

Female↗
PubMed2002

Usefulness of endoscopic ultrasonography in the diagnosis of congenital esophageal stenosis.

BACKGROUND/PURPOSE: Endoscopic ultrasonography (EUS) is considered a potentially useful tool to investigate structural abnormalities of the esophagus in pediatric patients, as in adults. The aim of this study was to evaluate the usefulness of EUS for the diagnosis of congenital esophageal stenosis. METHODS: High-frequency catheter probe EUS was performed under general anesthesia in 2 patients who had congenital esophageal stenosis. RESULTS: A 4-year-old boy with anorectal anomaly showed tapered narrowing in the distal esophagus, which was not ameliorated with balloon dilatation. High-frequency catheter probe EUS showed hypertrophy of the muscular layer in the esophageal wall at the narrowed portion, but no images suggested the presence of tracheobronchial remnants. The histologic diagnosis of fibromuscular hypertrophy was confirmed at esophagoplasty. A 5-month-old boy with Gross C-type esophageal atresia and symptomatic gastroesophageal reflux showed tapered narrowing in the middle esophagus on esophagography. The symptoms of stenosis were not ameliorated by balloon dilatation performed 4 times. High-frequency catheter probe EUS showed hyperechoic lesions suggesting cartilage at the esophageal narrowing. The diagnosis of tracheobronchial remnants was confirmed by the finding of 2 pieces of cartilage in the specimen obtained at the time of esophageal resection. CONCLUSION: EUS can be applied to show structural abnormalities of the esophageal wall even in pediatric patients with congenital esophageal stenosis and is useful for planning the therapeutic strategy.

Child, Preschool↗
PubMed2002

P53 gene mutations in pleuropulmonary blastomas.

Pleuropulmonary blastoma (PPB) is rare childhood tumor oniginating from either lung or pleura. Although several cytogenetic changes, such as tisomy 2, trisomy 8, and loss of 17p material, have been reported, evidence of gene mutations is still lacking. Pathologically, PPB shares similarities with rhabdomyosarcoma in which p53 mutations arefrequently detected. Possible implication of p53 mutations in PPB was investigated. PPBs of 3 patients were analyzed for occurrence of p53 mutations by using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) method, and the nature of mutations was confirmed by direct sequencing. Two PPBs were confirmed to harbor p53 mutations. One was a Val to Leu substitution at codon 173, and another was a ArgArg to TrpCys substitution at codons 282 and 283. In each tumor, only the mutated allele was detected, suggesting inactivation of p53. Both patients with mutations had fatal outcome, while the remaining patient in whom no mutation was detected is disease free for 3 years after completion of treatment. The results raise the possibility that p53 inactivation can occur as a nonrandom genetic change involving the pathogenesis and outcome of PPB. Further studies in a larger series are necessary to clarify these matters.

Amino Acid Substitution↗
PubMed2002

Evaluation of indexes of in vivo manganese status and the optimal intravenous dose for adult patients undergoing home parenteral nutrition.

BACKGROUND: There are no accurate indexes for determining the status of manganese in humans, and there is no clear recommended daily dose of this essential trace element to be administered in total parenteral nutrition solutions. OBJECTIVE: The objectives were to evaluate accurate indexes of manganese status and elucidate the optimal manganese dose to be administered to adult patients undergoing home parenteral nutrition. DESIGN: Patients were administered total parenteral nutrition solutions providing 0, 1, 2, or 20 micromol Mn/d according to an on-off design, after which manganese concentrations in whole blood and plasma were determined. Magnetic resonance imaging (MRI) was performed to determine the intensity on T(1)-weighted images (MRI intensity) and T(1) values in the globus pallidus. Hematologic and biochemistry tests were also performed. RESULTS: High degrees of correlation were found between whole-blood manganese concentrations and both MRI intensity (r = 0.7728) and T(1) values (r = -0.7519) in the globus pallidus. A strong negative correlation was found between MRI intensity and T(1) values (r = -0.8407). The dose of 1 micromol Mn/d caused no change in MRI intensity or T(1) values, and the whole-blood manganese concentration remained within the normal range in all patients. CONCLUSIONS: Whole-blood manganese concentrations and MRI intensity and T(1) values in the globus pallidus are useful indexes of the status of manganese in humans. The optimal dose of manganese may be 1 micromol/d for adult patients undergoing home parenteral nutrition.

Adolescent↗
PubMed2002

Characterization of L-glutamine transport by a human neuroblastoma cell line.

This study characterized the Na+-dependent transport of L-glutamine by a human neuroblastoma cell line, SK-N-SH. The Na+-dependent component represented >95% of the total glutamine uptake. Kinetic studies showed a single saturable high-affinity carrier with a Michaelis constant (K(m)) of 163 +/- 23 microM and a maximum transport velocity (Vmax) of 13,713 +/- 803 pmol x mg protein(-1) x min(-1). Glutamine uptake was markedly inhibited in the presence of L-alanine, L-asparagine, and L-serine. Li+ did not substitute for Na+. These data show that L-glutamine is predominantly taken up through system ASC. Glutamine deprivation resulted in the decrease of glutamine transport by a mechanism that decreased Vmax without affecting K(m). The expression of the system ASC subtype ASCT2 decreased in the glutamine-deprived group, whereas glutamine deprivation did not induce changes in system ASC subtype ASCT1 mRNA expression. Adaptive increases in Na+-dependent glutamate, Na+-dependent 2-(methylamino)isobutyric acid, and Na+-independent leucine transport were observed under glutamine-deprived conditions, which were completely blocked by actinomycin D and cycloheximide. These mechanisms may allow cells to survive and even grow under nutrient-deprived conditions.

Amino Acid Transport System ASC↗
PubMed2002

Axin, the main component of the Wnt signaling pathway, is not mutated in kidney tumors in children.

The Wnt signaling pathway is essential for embryonic development and can be involved in tumorigenesis when aberrantly activated. In a subset of Wilms' tumors, beta-catenin mutations have been identified, and this suggested that abnormally activated Wnt signaling may contribute to tumorigenesis of this tumor. Because Axin has been recognized as a main component of Wnt signaling, and its mutations were reported in several types of malignancies, we analyzed Axin gene mutations in 22 pediatric renal tumors. Twenty-four sets of the primers, which cover the whole coding region of the Axin gene, were used for PCR-SSCP analyses. Samples revealing aberrant band patterns were further analyzed for sequencing. We have only identified 4 silent mutations in the coding region and 3 intronic polymorphisms in Axin gene, accordingly no pathogenetic gene mutations were detected. Our results indicated that mutations of Axin gene as a mechanism of tumorigenesis are not associated with pediatric renal tumors including Wilms' tumors.

Axin Protein↗
PubMedDate not supplied

Umbilical cord ulcer associated with fetal jejunal atresia: report of 2 cases.

We report 2 cases of umbilical cord ulcer associated with fetal jejunal atresia. Both of them developed a severe intrauterine hemorrhage, followed by fetal heart rate decelerations, and underwent emergency cesarean section. Bloody amniotic fluid and umbilical cord ulcers were observed in both cases. Although both cases were successfully resuscitated, neurological impairment and renal failure developed in 1 case due to prolonged asphyxia. In a review of the literature, umbilical cord ulcer was associated only with congenital duodenal atresia or jejunal atresia, but not with ileal atresia. Although the prenatal diagnosis of duodenal or upper jejunal atresia has been established, the prenatal diagnosis of this complication has not been reported. In such cases, detailed examination of the umbilical cord by ultrasonography may be useful for the prenatal diagnosis of this disease.

Adult↗