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Biomedical subjects

Hiroyuki Kobayashi

Publications and source records attributed to Hiroyuki Kobayashi.

At least 109 records · Page 6Linked to original sources
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 pre-clinical assessment model of rat autogeneic bone marrow stromal cell transplantation into the central nervous system.

In order to verify the biological aspects of 'autogeneic' bone marrow stromal cells (BMSC) transplantation for neurological disorders, we aimed our study towards the assessment of the survival, distribution, and differentiation of autologous BMSC in the central nervous system (CNS). We harvested rat BMSC from femur bones, and the nuclei were then fluorescently labeled by a 24-h co-culture with bis-benzimide. These BMSC were stereotactically injected into the striatum (n=6) or thoracic cord (n=8) of each animal. We evaluated the distribution and differentiation of 'autogeneic' BMSC in the brain and spinal cord after 4 weeks, using the immunohistochemistry technique. We found some injected cells in the ipsilateral striatum, hippocampus, neocortex, and bilateral corpus callosum, and approximately 20% and 15% of the engrafted cells expressed neuronal and astrocytic markers, respectively. Other injected cells were distributed in the dorsal funiculus and adjacent gray matter, and about 10% and 15% of these cells expressed neuronal and astrocytic markers, respectively. Although the precise mechanism of BMSC transdifferentiation still remains unclear, the present results show that 'autogeneic' BMSC could highly differentiate into their own CNS neural cells, suggesting that they are surrounded by favorable conditions.

Animals↗
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

Serum basic fibroblast growth factor as a marker of reflux nephropathy.

PURPOSE: The authors investigated whether serum basic fibroblast growth factor (b-FGF) can be used as a noninvasive marker of renal parenchymal damage (scarring) in cases of vesicoureteric reflux (VUR). METHODS: Serum levels of b-FGF were measured in 120 children with known grade III to grade V VUR and 21 controls using a standard enzyme-linked immunosorbent assay technique. RESULTS: Sixty-five children had grade III VUR, 39 had grade IV, and 16 had grade V. Renal scarring was seen in 43 children on radionuclide scanning. There were no significant differences between serum b-FGF levels for different grades of VUR without scarring and controls. However, serum b-FGF levels were significantly higher in VUR patients with renal scarring than in patients with VUR without renal scarring (P < .001). CONCLUSIONS: This report is the first to document serum b-FGF profiles in children with VUR and renal scarring. The authors recommend measuring it as a simple, noninvasive marker of renal scarring in cases of VUR.

Adolescent↗
PubMed2004

Laparoscopic injection of dermabond tissue adhesive for the repair of inguinal hernia: short- and long-term follow-up.

PURPOSE: Is laparoscopic injection of 2-octyl-cyanoacrylate tissue adhesive (Dermabond: Db) into the inguinal hernia sac (IHS) effective for inguinal hernia repair? METHODS: Thirty male 4-week-old Lewis rats were used as subjects for this study. In the right Db (R-Db) group (n = 10), a fine catheter was passed through an 18-guage indwelling intravenous cannula inserted in the right lower quadrant, and 0.2 mL Db was injected into the right IHS under laparoscopic control. The left side was not treated. Both IHSs were treated in the bilateral Db (B-Db) group (n = 10). In the no Db (N-Db or control) group (n = 10), only laparoscope insertion was performed. Herniography was performed before death. B-Db and N-Db rats were mated 50 days after treatment. Half of all rats were killed 2 months after treatment and the remaining half 12 months after treatment. RESULTS: All rats survived until killing. Macroscopic findings postdeath confirmed herniography results; treated IHS were closed, and untreated IHS were patent. There were minor adhesions in 3 of 20 treated rats. Sperm were identified in the vaginas of all mated rats. CONCLUSIONS: These results suggest that our new technique is simple, safe, and reliable as an alternative to standard operative repair for inguinal hernia.

Animals↗
PubMed2004

Laparoscopy-assisted surgery for prenatally diagnosed small bowel atresia: simple, safe, and virtually scar free.

PURPOSE: The aim of this study was to describe a new technique for the surgical management of prenatally diagnosed small bowel atresia. METHODS: Under general anesthesia, a 5-mm trocar was inserted using an open technique through an intraumbilical incision. The proximal atretic bowel end was identified using laparoscopy and mobilized toward the umbilicus using an additional 3-mm trocar inserted in the left lower quadrant. The umbilical trocar then was removed, and a ring retractor was inserted into the trocar site and used to expand the wound to deliver both atretic bowel ends. The bowel was repaired and returned to the abdomen through the umbilical wound. The umbilical fascia and skin were closed conventionally. RESULTS: Three patients were reviewed. Two had minimal abdominal distension, and the atretic bowel ends could be identified easily; laparoscopy-assisted surgery was successful. The third case had significant dilatation, and laparotomy was required. Postoperatively, there was minimal abdominal scarring, and the umbilicus was normal in appearance. CONCLUSIONS: Although this experience is limited to 3 patients, this technique is simple, safe, and virtually scar free and can be applied for the treatment of neonates with prenatally diagnosed small bowel atresia, especially if there is minimal abdominal distension at birth.

Cicatrix↗
PubMed2004

Giant, highly vascular sacrococcygeal teratoma: report of its excision using the ligasure vessel sealing system.

Reports about giant, highly vascular sacrococcygeal teratoma (GHV-SCT) are uncommon. A boy with a prenatally diagnosed GHV-SCT was born at 34 weeks' gestation weighing 3,716 g. At birth, the GHV-SCT was 20 x 17 x 14 cm. After initial devascularization using an aortic snare, excision of the GHV-SCT was started using monopolar diathermy, but hemorrhage from cutaneous collateral vessels was difficult to control, and individual ligation of vessels was extremely time consuming. The authors then used the LigaSure (LS) vessel sealing system (Valleylab, Boulder, CO) to control intraoperative hemorrhage. Hemostasis was achieved easily with LS, without any need for vessel ligation; the operative field was dry and the efficiency of excision enhanced. Total operating time was 255 minutes, but excision of the GHV-SCT itself took only 16 minutes. The GHV-SCT weighed 1,208 g or 325.1 g/kg body weight. Total blood loss was 77 mL or 20.7 mL/kg body weight, which was minimal compared with other cases in the literature. At the last follow-up examination, 7 months after surgery, he remains well with no evidence of recurrence. LS was extremely useful for controlling intraoperative hemorrhage in this case, and we strongly recommend its selective use for excising highly vascular SCT.

Hemostatic Techniques↗
PubMed2004

Mucosal neuroendocrine cell abnormalities in patients with chronic constipation.

OBJECTIVES: The aim of this study was to examine the distribution of neuroendocrine cells (NEC) in patients with chronic constipation (CC) as a means of establishing a relationship between pathology, symptomatology and treatment. METHODS: Rectal biopsy specimens from 43 patients with CC (aged 17-82 years) and 20 age-matched normal controls were examined histopathologically using haematoxylin and eosin, and immunohistochemically using antibodies against chromogranin-A (Ch-A) and serotonin (5-HT) to detect NEC. The number of positive NEC per 70 crypts (CR) was counted and expressed as the ratio of NEC/CR. CC patients were divided into groups based on management, then compared using NEC/CR. RESULTS: CC was managed conservatively in 29 patients (group A) and invasively in 14. Of these 14, 10 had normal histology (group B) and four had typical histopathological signs of intestinal neuronal dysplasia (IND; group C). All control specimens were unremarkable. In controls, NEC/CR was 0.94+/-0.33 for Ch-A and 0.32+/-0.08 for 5-HT. In group A, NEC/CR was 2.23+/-0.13 for Ch-A and 1.02+/-0.06 for 5-HT. In group B, it was 2.79+/-0.18 for Ch-A and 1.72+/-0.33 for 5-HT. In group C, it was 3.12+/-0.22 for Ch-A and 2.32+/-0.14 for 5-HT. The increase in Ch-A and 5-HT immunoreactive cells in groups B and C compared with controls was greater (p<0.01, p<0.05) than the increase seen in group A compared with controls (p<0.01, p<0.05). CONCLUSIONS: These results demonstrate that increased numbers of NEC may play a role in the abnormal bowel function seen in CC, and may have some relationship with the development of giant submucosal ganglia in IND.

Adult↗
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

Functional characterization of a catabolic plasmid from polychlorinated- biphenyl-degrading Rhodococcus sp. strain RHA1.

Rhodococcus sp. strain RHA1, a potent polychlorinated-biphenyl (PCB)-degrading strain, contains three linear plasmids ranging in size from 330 to 1,100 kb. As part of a genome sequencing project, we report here the complete sequence and characterization of the smallest and least-well-characterized of the RHA1 plasmids, pRHL3. The plasmid is an actinomycete invertron, containing large terminal inverted repeats with a tightly associated protein and a predicted open reading frame (ORF) that is similar to that of a mycobacterial rep gene. The pRHL3 plasmid has 300 putative genes, almost 21% of which are predicted to have a catabolic function. Most of these are organized into three clusters. One of the catabolic clusters was predicted to include limonene degradation genes. Consistent with this prediction, RHA1 grew on limonene, carveol, or carvone as the sole carbon source. The plasmid carries three cytochrome P450-encoding (CYP) genes, a finding consistent with the high number of CYP genes found in other actinomycetes. Two of the CYP genes appear to belong to novel families; the third belongs to CYP family 116 but appears to belong to a novel class based on the predicted domain structure of its reductase. Analyses indicate that pRHL3 also contains four putative "genomic islands" (likely to have been acquired by horizontal transfer), insertion sequence elements, 19 transposase genes, and a duplication that spans two ORFs. One of the genomic islands appears to encode resistance to heavy metals. The plasmid does not appear to contain any housekeeping genes. However, each of the three catabolic clusters contains related genes that appear to be involved in glucose metabolism.

Amino Acid Sequence↗
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↗
PubMed2004

Expression level of MDR1 message in peripheral blood leukocytes from healthy adults: a competitive nucleic acid sequence-based amplification assay for its determination.

Accurate quantification of multidrug resistance-1 gene (MDR1) expression in target cells would be of important therapeutic value in predicting cellular response to anticancer drugs. Because certain normal cells in peripheral blood physiologically express MDR1, increasing the sensitivity of the detection methods might result in confounding low-degree expression in tumor cells with physiologic expression in normal cells. The purpose of this study was to determine MDR1 mRNA expression levels in peripheral blood leukocytes obtained from healthy adult volunteers using a competitive nucleic acid sequence-based amplification (NASBA) assay. We determined the reference intervals of MDR1 mRNA expression in peripheral blood obtained from 98 healthy adults by measuring its expression with the quantitative NASBA assay between 5.50 x 10(4) copies/microg RNA and 6.76 x 10(5) copies/microg RNA. The new reference intervals were evaluated using a number of sensitive or resistant cell lines as control; positive or negative MDR1 expression was clearly demonstrated. We also reevaluated MDR1 expression levels in leukemia cells obtained from patient peripheral blood; 18 of 31 samples (58%) exceeded the newly established upper reference limit. The cutoff value established could be used to distinguish significant MDR1 expression in tumor cells from physiologic expression in certain normal cells coexistent in peripheral blood.

ATP Binding Cassette Transporter, Subfamily B, Mem↗