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Biomedical subjects

Hiroyuki Kobayashi

Publications and source records attributed to Hiroyuki Kobayashi.

At least 19 recordsLinked to original sources
PubMed2005

Roux-en-Y hepaticojejunostomy or hepaticoduodenostomy for biliary reconstruction during the surgical treatment of choledochal cyst: which is better?

We reviewed our experience of Roux-en-Y hepaticojejunostomy (RYHJ) and hepaticoduodenostomy (HD) performed for the surgical repair of choledochal cyst (CC), with special emphasis on postoperative complications related to the type of biliary reconstruction performed. Eighty-six patients underwent primary cyst excision for CC from 1986 to 2002 at our institution. Forty-six cases with concurrent intrahepatic bile duct dilatation (IHBD) were excluded because HD was not used for biliary reconstruction if IHBD was present. Thus, 28 cases had RYHJ, and 12 had HD. Differences between the RYHJ and HD groups with respect to type of CC, age at cyst excision, and length of follow-up were not statistically significant. However, the incidences of postoperative complications related to biliary reconstruction, such as endoscopy-proven bilious gastritis due to duodenogastric bile reflux [4/12 (33.3%) of the HD group], and adhesive bowel obstruction/cholangitis [2/28 (7.1%) of the RYHJ group] were significantly different (p<.05). Our experience suggests that HD is not ideal for biliary reconstruction in CC because of a high incidence (33.3%) of complications due to duodenogastric bile reflux. Currently, RYHJ is our exclusive technique of choice for biliary reconstruction during the surgical repair of CC.

Anastomosis, Roux-en-Y↗
PubMed2005

Serum soluble vascular cell adhesion molecule-1 (VCAM-1) concentrations in children with reflux nephropathy.

Systemic inflammatory disorders causing renal tissue damage do so by the adherence of polymorphonuclear leukocytes to endothelium, a process that is mediated by cell surface adhesion molecules. We determined the circulating levels of serum vascular cell adhesion molecule-1 (VCAM-1) in vesicoureteric reflux (VUR) patients and investigated the relationship between serum VCAM-1, grade of VUR, and secondary renal scarring. Serum levels of VCAM-1 were measured in 53 children aged between 3 months and 15 years with VUR (13 had grade III, 29 had grade IV, and 11 had grade V) and 25 controls using ELISA. Radionuclide scanning was used to assess renal scarring. Renal scarring was found in 29 of the 53 subjects. Serum VCAM-1 was significantly higher in subjects with high grades of VUR without renal scarring (grade IV: 715.9+/-121.0 ng/ml; grade V: 778.5+/-33.2ng/ml) compared with subjects with grade III VUR without renal scarring (609.8+/-64.3ng/ml, p<0.01). Serum VCAM-1 was also significantly higher in subjects with high grades of VUR with renal scarring (grade IV: 791.2+/-131.9ng/ml; grade V: 1171.8+/-235.6 ng/ml) compared with subjects with grade III VUR with renal scarring (687.3+/-163.4 ng/ml, p<0.001).

Adolescent↗
PubMed2005

Posterior urethral diverticulum after laparoscopic-assisted repair of high-type anorectal malformation in a male patient: surgical treatment and prevention.

Currently, laparoscopic-assisted colon pull-through (LACPT) is the treatment of choice for male patients with high-type imperforate anus and rectourethral fistula. Since laparoscopy was introduced for treating this condition, reports concerning post-LACPT complications are rare. Here we discuss the case of a boy, now 3.5 years old, born at 37 weeks' gestation weighing 2,300 g, who was diagnosed with rectobulbar urethral fistula (RUF) at birth. LACPT was performed when the boy was 11 months old and weighed 7.2 kg. No intraoperative complications occurred, and the initial post-LACPT course was uneventful. When he was 2 years old, he developed dysuria requiring urethral catheterization. Diagnostic radiology confirmed a large cystic mass behind the bladder, suggestive of a posterior urethral diverticulum (PUD). Histopathology of the excised mucosa of the cyst showed colonic mucosa, confirming that the cyst was indeed an enlarged residual RUF. We discuss our treatment and our approach to prevention.

Anus, Imperforate↗
PubMed2005

Cholecystectomy alone is inadequate for treating forme fruste choledochal cyst: evidence from a rare but important case report.

Treatment of "forme fruste" choledochal cyst (FFCC) where pancreaticobiliary malunion (PBMU) is associated with minimal dilatation of the common bile duct (CBD) remains controversial. PBMU allows pancreaticobiliary reflux to occur, which causes complications such as recurrent pancreatitis and gallbladder cancer. Therefore, some surgeons opt to treat FFCC by cholecystectomy alone in order to prevent gallbladder cancer, with the result that pancreaticobiliary reflux could still occur. Our treatment of choice-excision of both the CBD and the gallbladder, followed by Roux-en-Y hepatico-jejunostomy-can eliminate pancreaticobiliary reflux and prevent complications. Our case, a 2-year-old boy, initially presented to a hospital abroad with recurrent abdominal pain. Endoscopic retrograde cholangiopancreatography showed massive protein plugs impacted in the papilla of Vater and mild CBD dilatation, but PBMU was not identified. Intraoperative cholangiography performed during laparotomy 5 days later suggested PBMU with minimal CBD dilatation. Despite these findings, cholecystectomy with T-tube drainage was performed rather than CBD excision with biliary reconstruction. Postoperative T-tube cholangiography clearly showed PBMU. The T-tube was removed after 2 weeks, and 3 months later the boy was referred to us because of recurrent pancreatitis. We performed CBD excision and Roux-en-Y hepatico-jejunostomy. His postoperative course was uneventful, and he is well after 10 years of follow-up. This case provides strong evidence that CBD excision with biliary reconstruction is mandatory for treating FFCC and, conversely, that cholecystectomy alone is inadequate for treating children with FFCC.

Anastomosis, Roux-en-Y↗
PubMed2004

INK4a/Arf is required for suppression of EGFR/DeltaEGFR(2-7)-dependent ERK activation in mouse astrocytes and glioma.

Amplification of the epidermal growth factor receptor (EGFR) or expression of its constitutively activated mutant, DeltaEGFR(2-7), in association with the inactivation of the INK4a/Arf gene locus is a frequent alteration in human glioblastoma. The notion of a cooperative effect between these two alterations has been demonstrated in respective mouse brain tumor models including our own. Here, we investigated underlying molecular mechanisms in early passage cortical astrocytes deficient for p16(INK4a)/p19(Arf) or p53, respectively, with or without ectopic expression of DeltaEGFR(2-7). Targeting these cells with the specific EGFR inhibitor tyrphostin AG1478 revealed that phosphorylation of ERK was only abrogated in the presence of an intact INK4a/Arf gene locus. The sensitivity to inhibit ERK phosphorylation was independent of ectopic expression of DeltaEGFR(2-7) and independent of the TP53 status. This resistance to downregulate the MAPK pathway in the absence of INK4a/Arf was confirmed in cell lines derived from our mouse glioma models with the respective initial genetic alterations. Thus, deletion of INK4a/Arf appears to keep ERK in its active, phosphorylated state insensitive to an upstream inhibitor specifically targeting EGFR/DeltaEGFR(2-7). This resistance may contribute to the cooperative tumorigenic effect selected for in human glioblastoma that may be of crucial clinical relevance for treatments specifically targeting EGFR/DeltaEGFR(2-7) in glioblastoma patients.

Animals↗
PubMed2004

Association between cardiovascular autonomic neuropathy and left ventricular hypertrophy in diabetic haemodialysis patients.

BACKGROUND: Patients with diabetic nephropathy are likely to have neurological complications including cardiovascular autonomic dysfunction, which is related to increased risk of mortality. We investigated whether cardiovascular autonomic neuropathy is associated with left ventricular hypertrophy (LVH) in diabetic haemodialysis patients. METHODS: Holter electrocardiography was carried out for 24 h with time and frequency domain analyses of heart rate variability in 154 diabetic (age 62+/-11 years) and 63 non-diabetic haemodialysis patients (62+/-10 years). The left ventricular mass index (LVMI) was determined by echocardiography. We used the percentage of differences exceeding 50 ms between adjacent normal RR intervals (pNN50) in time domain analysis and the power in the high-frequency range (HF: 0.15-0.40 Hz) in frequency domain analysis as indicators of parasympathetic activity. RESULTS: The mean LVMI was greater in diabetic than in non-diabetic patients (168+/-63 vs 144+/-54 g/m(2), P<0.01). LVMI inversely correlated with pNN50 (r = -0.270, P = 0.0007, n = 154) and HF (r = -0.277, P = 0.0005, n = 154) in diabetic patients, but not in non-diabetic patients. By multiple logistic analysis, LVH was strongly associated with pNN50 (odds ratio 0.088; 0, <2%; 1, >/=2%) and HF (odds ratio 0.058; 0, <500 ms(2); 1, >/=500 ms(2)) in diabetic patients. CONCLUSIONS: Impaired parasympathetic activity, which indicates cardiovascular autonomic neuropathy, was associated with the presence of LVH in diabetic haemodialysis patients. The co-existence of cardiovascular autonomic neuropathy and LVH may be one of the key factors for the high incidence of cardiovascular events in diabetic haemodialysis patients.

Aged↗
PubMed2004

Multifaceted pancreatic mesenchymal control of epithelial lineage selection.

Mouse pancreatic development is critically dependent on epithelial-mesenchymal interactions. The pancreas differs from other epithelial-mesenchymal organs in that the epithelium gives rise to both epithelial exocrine cells and non-epithelial endocrine cells. We studied the nature of the interactions between the epithelium and mesenchyme with respect to the decision between exocrine and endocrine lineages. We show here a tripartite influence of mesenchyme on the developing epithelium. First, close proximity or contact of mesenchyme with the epithelium induces exocrine differentiation. Second, this mesenchymal proximity to the epithelium suppresses endocrine differentiation. Third, mesenchyme has an overall enhancing effect on the degree of insulin differentiation, suggesting a pro-endocrine effect in those epithelial cells at a distance from the mesenchyme. Proximity or contact between the mesenchyme and epithelium appeared to be necessary for the pro-exocrine effects of mesenchyme. We found that, in a co-culture system, NIH3T3 cells were able to substitute for mesenchyme in exocrine induction as well as in both the endocrine induction and endocrine inhibition, implying that the responsible molecules are not unique to pancreatic mesenchyme. Laminin appears to be a key molecule mediating the epithelial-mesenchymal interactions that lead to exocrine differentiation, since inhibition of laminin expression resulted in blockage of the pro-exocrine induction of mesenchyme.

Animals↗
PubMed2004

Recipient non-hematopoietic bone marrow cells in the intestinal graft after fetal small intestinal transplantation.

We examined whether non-hematopoietic BM cells can migrate into the intestinal graft after fetal small intestinal transplantation (FSITx). Fetal small intestine from donor C57BL/6 mice was transplanted into the rectus abdominis of recipient C57BL/6 mice with only green fluorescent protein (GFP) BM cells (syngeneic FSITx). Intestinal grafts were harvested on days 5, 10, and 30 after FSITx and stained immunohistochemically using anti-CD45 antibody (a marker for hematopoietic BM cells). Although there were no GFP-positive cells identified in the epithelium of the graft intestinal villi, there were a few cells positive for both GFP and CD45 in the lamina propria on day 5 after FSITx, and many present on days 10 and 30. In some grafts there were only cells that were GFP positive/CD45 negative (i.e., non-hematopoietic BM cells) found in the lamina propria on days 10 and 30. These data indicate that non-hematopoietic BM cells as well as hematopoietic BM cells can migrate from the recipient's bone marrow, suggesting that recipient mesenchymal stem cells may be strongly implicated in graft regeneration and development after FSITx.

Animals↗
PubMed2004

Suspicion of prenatal pyriform sinus cyst and fistula: a case report.

There has been no report describing suspected prenatal pyriform sinus (PS) cyst and fistula. We report a case suspected by prenatal ultrasonography and fetal MRI. A large cystic mass was found in the left neck of the fetus. After the baby was born, preoperative laryngoscopic catheterization of the fistula tract was used to confirm the diagnosis and greatly facilitated the identification and excision of the PS cyst and fistula.

Adult↗
PubMed2004

Intracorporeal electrohydraulic lithotripsy for intrahepatic bile duct stone formation after choledochal cyst excision.

An 18-year-old girl who had undergone excision of a choledochal cyst and Roux-en-Y hepatico-jejunostomy at another hospital when 23 months old was referred to our department because of recurrent cholangitis. Radiological investigations showed stones lying in minimally dilated, right posterior intrahepatic bile ducts (IHBD). At laparotomy, the hepatico-jejunostomy site was incised, and a flexible endoscope inserted into the IHBD. Multiple stones packed in the IHBD were easily fragmented using an electro-hydraulic lithotripsy (EHL) device inserted through the endoscope, and removed. There were no EHL-related complications, and her postoperative progress was uneventful. She is currently well with no episodes of cholangitis after a follow-up period of 3 years. EHL is a simple, effective alternative method for removing IHBD stones after choledochal cyst excision. To the best of our knowledge, this is the first report of EHL being used to remove stones that developed in the IHBD after choledochal cyst excision.

Adolescent↗
PubMed2004

A competitive nucleic acid sequence-based amplification assay for the quantification of human MDR1 transcript in leukemia cells.

BACKGROUND: Because clinical drug resistance is caused by low-grade expression of a responsible gene, highly sensitive methods are desirable for its detection in clinical settings. We developed a quantitative nucleic acid sequence-based amplification (NASBA) assay for multidrug resistance-1 (MDR1) transcripts, and applied it to clinical samples. METHOD: MDR1 transcripts were amplified using the NASBA technique combined with sandwich hybridization of amplified MDR1 mRNA followed by chemiluminescence detection on an automated analyzer. Quantification of MDR1 mRNA was achieved through competitive coamplification of in vitro-generated RNA, which acts as an internal control. RESULTS: The competitive NASBA assay exhibited higher sensitivity (reliable detection limit was 100 copies of MDR1 mRNA) and linearity over a broader dynamic range (7 logarithmic orders) than the competitive reverse transcription-polymerase chain reaction assay. All 33 clinical samples obtained from patients with leukemia were successfully assayed, demonstrating its feasibility. MDR1 expression-compensated with beta-actin expression-ranged from 1.4 x 10(2) to 2.5 x 10(6) (median 4.8 x 10(5)) copies/microg RNA, while the range of MDR1 expression in peripheral blood samples from 15 healthy adults was from 8.9 x 10(4) to 5.2 x 10(5) (median 2.2 x 10(5)) copies/microg RNA. MDR1 expression in 8 of 33 clinical samples exceeded the median of healthy adult samples. CONCLUSIONS: The competitive NASBA assay is applicable to MDR1 mRNA quantification in clinical samples and would contribute to detection of clinical multidrug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2004

Inflammatory changes secondary to postoperative complications of Hirschsprung's disease as a cause of histopathologic changes typical of intestinal neuronal dysplasia.

PURPOSE: The aim of this study was to clarify the pathogenesis of intestinal neuronal dysplasia (IND). METHODS: The bowel habits of 36 postoperative HD patients were assessed retrospectively. Twenty-five had no complaints. Seven had persistent enterocolitis and were the focus of our study. They were divided into group A (n = 2) if they were severe and had associated postoperative surgical complications, and group B (n = 5) if they were mild. The histological changes were assessed. RESULTS: The 7 patients who had persistent enterocolitis postoperatively had no AchE activity in the mucosa, and there was normal distribution of submucosal and myenteric ganglia in the proximal resection margin. Rectal biopsies performed postoperatively for investigation of persistent enterocolitis in group A showed inflammatory changes and typical histopathologic features of IND such as abundant acetylcholinesterase (AchE)-positive nerve fibers in the lamina propria associated with giant submucosal ganglia and hyperganglionosis, and in group B there was increased AchE activity without hyperganglionosis or giant ganglia. CONCLUSIONS: This is the first report of histopathologic changes typical of IND occurring in response to persistent enterocolitis related to postoperative complications of surgery for HD.

Acetylcholinesterase↗
PubMed2004

Acetylcholine-related bowel dysmotility in homozygous mutant NCX/HOX11L.1-deficient (NCX-/-) mice-evidence that acetylcholine is implicated in causing intestinal neuronal dysplasia.

BACKGROUND/PURPOSE: Homozygous mutant Ncx/Hox11L.1-deficient (Ncx-/-) mice develop mega-ileo-ceco-colon (mega-ICC) with a caliber change in the proximal colon. The authors investigated the mechanism of intestinal dysmotility in these mice. METHODS: Five-week-old Ncx-/- mice with mega ICC were compared with age-matched BDF1 control mice. Jejunum, ileum, and colon were excised from all mice and 1.0-cm-long strips of each organ, each with a resting tension of 0.5g, were suspended in an organ bath filled with Tyrode's solution at 37 degrees C and bubbled with a mixture of 95% oxygen and 5% carbon dioxide. Contractile responses to acetylcholine chloride (ACh), histamine, serotonin, and barium chloride (BaCl2) were recorded isometrically. RESULTS: For ACh, Ncx-/- mice had decreased distal colon circular muscle contraction only at lower doses and decreased distal colon longitudinal muscle contraction for all doses compared with controls (P <.05 or P <.01). In the proximal colon, Ncx-/- mice had increased circular muscle contraction only at higher doses and decreased longitudinal muscle contraction only at lower doses compared with controls (P <.01 or P <.05). ACh did not affect jejunum, and there were no significant effects on ileum. There was no response to histamine and serotonin by any part of the bowel, and the response to BaCl2 was the same for both Ncx-/- mice and controls. CONCLUSIONS: Only ACh differentially affected muscle contraction in Ncx-/- mice in the proximal and distal colon. Thus, ACh is implicated in causing the bowel dysmotility seen in Ncx-/- mice and human IND.

Acetylcholine↗
PubMed2004

Myocardial scintigraphy using a fatty acid analogue detects coronary artery disease in hemodialysis patients.

BACKGROUND: Coronary artery disease contributes significantly to mortality in end-stage renal disease (ESRD) patients. Single-photon emission computed tomography (SPECT) using an iodinated fatty acid analogue, iodine-123-methyl iodophenylpentadecanoic acid (123I-BMIPP), can assess fatty acid metabolism in the myocardium. We investigated the ability of 123I-BMIPP SPECT to detect coronary artery disease in hemodialysis patients compared with 201thallium chloride (201Tl) SPECT. METHODS: We prospectively studied 130 ESRD patients undergoing hemodialysis for a mean of 88.6 months (male/female, 77/53; mean age, 63.8 years). Dual SPECT using 123I-BMIPP and 201Tl was performed, followed by coronary angiography. SPECT findings were graded in 17 segments on a five-point scale (0, normal uptake; 4, none) and assessed as a summed score. RESULTS: By coronary angiography, 71.5% of patients (93/130) had significant coronary stenosis (> or =75%), and five patients showed coronary spasm without coronary stenosis. When a BMIPP summed score of 6 or more was defined as abnormal, sensitivity, specificity, and accuracy for detecting coronary artery disease by BMIPP SPECT were 98.0%, 65.6%, and 90.0%, respectively; in contrast, these parameters for detecting coronary artery disease by Tl SPECT were 84.7%, 46.9%, and 75.0%, respectively, when a Tl summed score of 1 or more was defined as abnormal. In receiver operating characteristic analysis, the area under the curve was 0.895 in BMIPP and 0.727 in Tl SPECT, respectively. CONCLUSION: Resting BMIPP SPECT is superior to Tl SPECT for detecting coronary lesions, and provides safe screening for coronary artery disease among maintenance hemodialysis patients.

Aged↗
PubMed2004

Identification of human p450 isoforms involved in the metabolism of the antiallergic drug, oxatomide, and its inhibitory effect on enzyme activity.

Oxatomide is an antiallergic drug used for the treatment of diseases mediated by type I allergy. Recently, it has been reported that terfenadine and astemizole, which have antiallergic actions similar to those of oxatomide, show side effects on the cardiovascular system, such as QT prolongation, ventricular arrhythmia and cardiac arrest. This might be because concomitant drugs such as itraconazole inhibit cytochrome P450 3A4 (CYP3A4), the enzyme responsible for degradation of terfenadine and astemizole, and thus the blood concentrations of the drugs are abnormally increased. On the other hand, isoforms of P450 involved in the metabolism of oxatomide have not been clarified. Therefore, we attempted to identify these isoforms using microsome preparations of in vitro expression systems derived from a human lymphoblastoid cell line. Oxatomide was metabolized by CYP2D6-Val and CYP3A4, but not by CYP1A2, CYP2C9-Arg, CYP2C9-Cys or CYP2C19. We also examined whether oxatomide showed inhibitory effects on metabolic activity of individual P450 isozymes using model substrates for each isozyme. Oxatomide did not inhibit the metabolism of the model substrates for CYP1A2, CYP2C9-Arg, CYP2C9-Cys and CYP2C19, but inhibited the degradation of those for CYP2D6-Val and CYP3A4. It was found that oxatomide is metabolized by CYP2D6 and CYP3A4 in human liver microsomes, and simultaneously acts as an inhibitor for these isoforms, responsible for the metabolism of the drug itself.

Anti-Allergic Agents↗