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Biomedical subjects

T Miyano

Publications and source records attributed to T Miyano.

At least 55 records · Page 3Linked to original sources
PubMed2000

Tubed latissimus dorsi musculocutaneous flaps for esophageal replacement in puppies: long-term follow-up.

PURPOSE: The aim of this study was to show that a tubed latissimus dorsi musculocutaneous flap (tubed LDMCF) may be useful for treating circumferential esophageal defects. METHODS: A segment of esophagus 3 vertebrae long was excised through a right thoracotomy in each of 6 puppies, and a tubed LDMCF was interposed between the cut ends of esophagus. The puppies were sacrificed after a mean follow-up period of 6.6 years. The tubed LDMCF was examined histologically. Functional integrity was assessed using barium meal and endoscopy before sacrifice. RESULTS: All puppies survived and grew normally on a normal diet, although 4 vomited occasionally. There was smooth passage of barium through the tubed LDMCF without stenosis, although endoscopy showed regrowth of hair. Histologically, no metaplasia, dysplasia, or malignancy was observed in any tubed LDMCF. CONCLUSIONS: The tubed LDMCF is technically safe, obviates the necessity for laparotomy, and long-term follow-up would suggest that it is histologically stable. Thus, it could become an alternative procedure for bridging esophageal defects.

Animals↗
PubMed2000

Idiopathic gastric perforation in neonates and abnormal distribution of intestinal pacemaker cells.

BACKGROUND/PURPOSE: The etiology of idiopathic gastric perforation (IGP) in neonates is unclear. Interstitial cells of Cajal (ICC) express tyrosine kinase receptor C-kit, and act as gastrointestinal pacemaker cells. Stem cell factor (SCF) is a C-kit ligand and plays an important role in immune system homeostasis in the gastrointestinal tract. The authors hypothesized that abnormal distribution of ICC or SCF in the gastric wall (ie, abnormal motility or impaired immunity) could predispose the stomach to IGP. METHODS: Stomachs obtained at postmortem from neonates who died of IGP (n = 7) and other causes (control group; n = 10) were used. Biopsy sections were taken at random from various sites in the stomach, including macroscopically intact areas, and labeled immunohistochemically using antibodies to C-kit(a marker for ICC) and SCF. RESULTS: In all control specimens, ICC were present between the muscle layers and around the myenteric plexuses of the stomach wall. In contrast, ICC were absent in all biopsy sections from 3 of the 7 IGP stomachs. In the remaining 4 IGP stomachs, there were fewer ICC in the muscle layers compared with controls, and ICC were absent around the myenteric plexuses. The distribution of SCF immunoreactivity in IGP and control specimens was similar. CONCLUSION: The findings suggest that a lack of ICC (ie, gastric hypomotility) may be implicated in the etiology of IGP in neonates.

Analysis of Variance↗
PubMed2000

Congenital biliary dilatation.

Congenital biliary dilatation is commonly associated with pancreaticobiliary malunion. Its etiology remains unknown. With the advent of accurate cholangiography, combined abnormalities of the intrahepatic duct, common channel, and pancreatic duct are being identified more frequently in patients with congenital biliary dilatation. Early diagnosis followed by cyst excision is the treatment of choice, even in asymptomatic cases. The treatment of intrahepatic and intrapancreatic ductal diseases such as intrahepatic duct dilatation and stone debris in the intrahepatic duct and common channel are also discussed. The value of intraoperative endoscopy as an adjunct to cyst excision for the prevention of postoperative complications is explained.

Bile Ducts, Intrahepatic↗
PubMed2000

Spindle formation and dynamics of gamma-tubulin and nuclear mitotic apparatus protein distribution during meiosis in pig and mouse oocytes.

This work focuses on the assembly and transformation of the spindle during the progression through the meiotic cell cycle. For this purpose, immunofluorescent confocal microscopy was used in comparative studies to determine the spatial distribution of alpha- and gamma-tubulin and nuclear mitotic apparatus protein (NuMA) from late G2 to the end of M phase in both meiosis and mitosis. In pig endothelial cells, consistent with previous reports, gamma-tubulin was localized at the centrosomes in both interphase and M phase, and NuMA was localized in the interphase nucleus and at mitotic spindle poles. During meiotic progression in pig oocytes, gamma-tubulin and NuMA were initially detected in a uniform distribution across the nucleus. In early diakinesis and just before germinal vesicle breakdown, microtubules were first detected around the periphery of the germinal vesicle and cell cortex. At late diakinesis, a mass of multi-arrayed microtubules was formed around chromosomes. In parallel, NuMA localization changed from an amorphous to a highly aggregated form in the vicinity of the chromosomes, but gamma-tubulin localization remained in an amorphous form surrounding the chromosomes. Then the NuMA foci moved away from the condensed chromosomes and aligned at both poles of a barrel-shaped metaphase I spindle while gamma-tubulin was localized along the spindle microtubules, suggesting that pig meiotic spindle poles are formed by the bundling of microtubules at the minus ends by NuMA. Interestingly, in mouse oocytes, the meiotic spindle pole was composed of several gamma-tubulin foci rather than NuMA. Further, nocodazole, an inhibitor of microtubule polymerization, induced disappearance of the pole staining of NuMA in pig metaphase II oocytes, whereas the mouse meiotic spindle pole has been reported to be resistant to the treatment. These results suggest that the nature of the meiotic spindle differs between species. The axis of the pig meiotic spindle rotated from a perpendicular to a parallel position relative to the cell surface during telophase I. Further, in contrast to the stable localization of NuMA and gamma-tubulin at the spindle poles in mitosis, NuMA and gamma-tubulin became relocalized to the spindle midzone during anaphase I and telophase I in pig oocytes. We postulate that in the centrosome-free meiotic spindle, NuMA aggregates the spindle microtubules at the midzone during anaphase and telophase and that the polarity of meiotic spindle microtubules might become inverted during spindle elongation.

Animals↗
PubMed2000

An annular pancreas derived from paired ventral pancreata, supporting Baldwin's hypothesis.

An annular pancreas is a rare malformation. It is generally accepted that the ring formation originates from a single ventral pancreas, as suggested by Lecco. No reports of resected and/or autopsied annular pancreata derived from paired ventral pancreata, thus supporting Baldwin's hypothesis, have been published. We describe an annular pancreas originating from paired ventral pancreata, thus supporting Baldwin's hypothesis, and attempt to clarify the pathogenesis of an annular pancreas. The patient was a 1-day-old Japanese male newborn, born at 32 weeks of pregnancy. He died from respiratory failure owing to esophageal atresia the next day. Autopsy incidentally revealed an annular pancreas that was examined histologically. Multiple 4 microm thick serial sections were obtained from paraffin-embedded pancreatic tissue. Sections for histologic analysis were subjected to hematoxylin-eosin staining and pancreatic polypeptide immunostaining. An unusually large pancreatic duct encircled by pancreatic tissue ran around the duodenum, and the duct was confirmed to flow into the major papilla. The islets of the encircling pancreas were positive for pancreatic polypeptide. A normal main and accessory pancreatic duct were also identified. Histologic and immunohistochemical evaluation revealed that the ring formation originated from the left lobe of paired ventral pancreata. An annular pancreas that was investigated histopathologically and immunohistochemically and found to support Baldwin's hypothesis is described.

Esophageal Atresia↗
PubMed2000

Intraoperative pancreatoscopy for pancreatic duct stone debris distal to the common channel in choledochal cyst.

BACKGROUND/PURPOSE: Pancreatic duct stone debris is a recognised problem in patients with choledochal cyst (CC). The authors present the use of intraoperative pancreatoscopy (IP) in diagnosis and treatment of pancreatic duct stone debris distal to the common channel (distal PDSD). METHODS: Sixty-seven patients with CC treated over the past 12 years were reviewed retrospectively. Distal PDSD was detected in 8 of these 67 cases (11.9%) using cholangiography. IP of the common channel or pancreatic duct at the time of surgery for CC was performed using a pediatric cystoscope in 7 of these 8 cases. RESULTS: All 8 patients had a long common channel. All presented with acute pancreatitis. In 7 of these 8 patients, IP was efficient in detecting and for removing distal PDSD by irrigation. In the remaining case associated with annular pancreas, distal PDSD was identified in the proximal pancreatic duct and was removed directly after incision of the pancreatic duct. Postoperative pancreatitis occurred in only 1 case. All patients are well after a mean follow-up period of 7.3 years. CONCLUSION: Distal PDSD should not be ignored. IP allows direct examination of the pancreatic duct system and facilitates complete removal of distal PDSD, which may be the cause of relapsing pancreatitis or pancreatolithiasis after radical surgery for CC.

Acute Disease↗
PubMed1999

Development to live young from bovine small oocytes after growth, maturation and fertilization in vitro.

Bovine oocytes (90 to 99 microns in diameter) were isolated from early antral follicles (0.5 to 0.7 mm in diameter). Cumulus-oocyte complexes (COC) with pieces of parietal granulosa were embedded in collagen gels and cultured for 14 d. After in vitro growth culture, oocytes recovered from the collagen gels were further matured, fertilized and cultured in vitro, and then were transferred to recipient cows. After 14 d of growth culture, 37% of the oocytes (203/556) showed normal morphology in the collagen gels. The mean diameter of the oocytes was 110.1 +/- 6.0 microns, significantly larger (P < 0.01) than before growth culture (94.8 +/- 2.7 microns), and 77% were at the germinal vesicle stage while 23% had undergone germinal vesicle breakdown. After 24 h of maturation culture followed by insemination, 27% of in vitro-grown oocytes reached the second metaphase, and 42% of the oocytes were normally fertilized. After insemination, 18.2% of in vitro-grown oocytes cleaved and 3.7% developed to the blastocyst stage. Three blastocysts obtained from in vitro-produced 90- to 99-micron oocytes were transferred to 3 recipients. One recipient subsequently became pregnant and delivered a live calf on Day 277. These results demonstrated for the first time that 90 to 99-micron oocytes from early antral follicles can complete growth and acquire full developmental competence in vitro so that live young can be produced after maturation, fertilization, subsequent culture in vitro, and transfer to recipient cows.

Animals↗
PubMed1999

Laparoscopic surgery in newborn infants.

BACKGROUND: Thanks to various technical innovations and advances in instrumentation, laparoscopic surgical intervention is now possible for certain congenital anomalies in children. To test the applicability of laparoscopic surgery in neonates, we reviewed our personal experience of neonatal laparoscopic surgery, focusing on cardiopulmonary function, surgical procedures, problems with devices, and degree of associated surgical stress. METHODS: We performed 65 laparoscopic procedures in neonates. Their ages ranged from 2 to 30 days old, and their body weights ranged from 1,980 to 4,780 g. All 65 laparoscopic procedures were carried out without mortality or serious morbidity. RESULTS: As complications, we encountered four cases of hypothermia due to rapid insufflation of carbon dioxide (CO(2)). We also found that relative hypercapnea (increase in end-tidal CO(2) as high as 61 mmHg) developed unless hyperventilation and a relatively high peak insufflation pressure were maintained during pneumoperitoneum. No cardiac depression developed at this insufflation pressure. Fluid and electrolyte balance during our cases of newborn laparoscopic surgery, as well as the doses and volumes of fluid and electrolytes administered, were identical to those required for open surgery. Interleukin-6 (IL-6) was measured serially to estimate the degree of associated surgical stress and was found to be significantly lower in neonates who had received laparoscopic procedures than in those who had received open procedures. CONCLUSION: Laparoscopic surgery can be carried out safely even in neonates.

Heart Function Tests↗
PubMed1999

Mast cells and gut nerve development: implications for Hirschsprung's disease and intestinal neuronal dysplasia.

BACKGROUND/PURPOSE: In Hirschsprung's disease (HD), the aganglionic bowel is characterized by the presence of hypertrophic nerve trunks and increased numbers of adrenergic and cholinergic nerve fibers. Intestinal neuronal dysplasia (IND), if associated with HD, occurs proximal to the aganglionic segment in HD, and is characterized by dysplasia of parasympathetic nerves, hyperganglionosis, and giant ganglia. However, the cause of such abnormalities in HD and IND is unclear. Recent reports that mast cells (MC) have been observed in direct contact with nerve fibers generally, suggest that MC are essential for nerve growth and repair. MC synthesize, store, and release nerve growth factor (NGF). NGF supports the development and functional maintenance of sympathetic and cholinergic neurons. The aim of this study was to examine the colonic distribution of MC with respect to nerves in HD and HD associated with IND. METHODS: MC and NGF were examined immunohistochemically in ganglionic, transitional, and aganglionic segments of colon from 20 patients with HD (five patients associated with IND) and 15 age-matched controls. MC were counted in each of five random fields using light microscopy (x100). RESULTS: Interestingly, aganglionic and IND segments had large numbers of MC in all layers compared with ganglionic segments in HD patients and controls (P< .0001). The number of MC in transitional segments was significantly less compared with ganglionic segments in HD patients and controls (P< .01). MC stained positively for NGF, and some were found in contact with abnormal hypertrophic nerve trunks in HD and giant ganglia in IND. CONCLUSIONS: MC may cause hypertrophic nerve trunks and giant ganglia by releasing NGF and also may be an important factor in the excessive development of cholinergic and adrenergic nerve fibers in HD and IND.

Colon↗
PubMed1999

Does probiotics administration decrease serum endotoxin levels in infants?

PURPOSE: The aim of this study was to examine whether administration of probiotics to infants can change the ratio of intestinal flora and thereby decrease serum endotoxin produced by potentially pathogenic microorganisms. METHODS: Nine infants including five with of biliary atresia, two with omphalocele, one each with Hirschsprung's disease and imperforate anus were studied. All patients were stable, and no antibiotics were given during this study. A probiotic mixture consisting of Streptococcus faecalis, Clostridium butyricum and Bacillus mesentericus was administered orally to each infant at 2 g/day for 2 weeks. Fecal aerobic and anaerobic bacterial cultures, serum endotoxin level, and other biochemical parameters were examined. RESULTS: In fecal cultures, anaerobic bacteria including Bifidobacterium increased significantly whereas Escherichia coli, Streptococcus, and Klebsiella tended to decrease. The ratio of anaerobic to aerobic bacteria increased five times as a result of administration of probiotics, and serum endotoxin levels decreased. CONCLUSIONS: Probiotics affect intestinal bacterial flora by increasing anaerobic bacteria and decreasing the population of potentially pathogenic microorganisms. A decrease in luminal endotoxin may result in less endotoxin translocation or bacterial translocation.

Administration, Oral↗
PubMed1999

Serum IFN-inducible protein-10: a new clinical prognostic predictor of hepatocyte death in biliary atresia.

PURPOSE: The aim of this study was to determine whether chemokines such as serum IP-10 levels in patients with biliary atresia (BA) correlate with liver function and histology and assess its value as a medium to long-term prediction of prognosis in postoperative BA patients. METHODS: Thirty postoperative BA patients (mean age, 10.8+/-3.5 years) and eight normal controls (mean age, 10.3+/-3.3 years) were studied. The BA patients were divided into three groups according to liver function. Group I (n = 8) was jaundice free, had normal liver function and no evidence of severe cholangitis or portal hypertension. Group II (n = 12) had moderate liver dysfunction. Group III (n = 10), had severe liver dysfunction. Hepatic histology was assessed using conventional needle biopsy. Serum IP-10 levels were determined using a specific enzyme-linked immunosorbent assay (ELISA). RESULTS: Serum levels of IP-10 in group III (458.0+/-240.0 pg/mL) were significantly higher than those in group II (233.6+/-126.9 pg/mL; P < .0001). Levels in group II were also significantly higher than those in group I (144.8+/-23.4 pg/mL; P < .05), but there was no significant difference between group I and controls (107.9+/-34.0 pg/mL). Liver biopsy findings showed a progression of fibrosis and mononuclear cell infiltration from group I to group III. There was intimal hyperplasia and swelling of endothelial cells of branches of the hepatic artery in the portal area in group III. CONCLUSION: Because IP-10 levels correlate closely with histological findings in postoperative BA patients, it would appear to play a specific role in hepatocyte death and hepatic artery changes, thus providing important information about progressive fibrosis in BA patients that facilitates treatment decision making and prediction of prognosis.

Biliary Atresia↗
PubMed1999

Long-term postsurgical outcome of biliary atresia.

BACKGROUND/PURPOSE: A successful Kasai procedure is effective in creating biliary drainage and radically altering the natural history of infants with biliary atresia (BA). Since its introduction in the 1950s, long-term follow-up would appear to show that only 30% to 50% of patients have a good long-term prognosis despite initially good surgical outcome. The authors reviewed their experience in treating BA from 1968 to 1997 to assess long-term outcome. MATERIALS AND METHODS: The records of 163 patients treated surgically for BA from 1968 to 1997 were reviewed. Forty-eight (29%) were alive at the end of 1997, of whom, 14 had received liver transplants (LT). Surviving patients who had not undergone transplantation were divided into two groups according to clinical condition: group A, normal liver function without cholangitis (CG) and portal hypertension (PH) and group B, liver dysfunction with CG or PH. The study period was divided arbitrarily into three periods, 1968 to 1975 (period I, n = 34); 1976 to 1985 (period II, n = 81); 1986 to 1997 (period III, n = 48). RESULTS: Thirty-four patients were alive without LT at the end of 1997. There were eight patients (mean age, 16.3+/-4.8 years) in group A, and 26 patients (mean age, 14.3+/-7.6 years) in group B. Recently, four group A patients (mean age, 19.3+/-1.9 years) shifted to group B because of sudden deterioration in condition involving severe CG with multiple bile lakes (n = 2), uncontrollable intestinal bleeding (n = 1), and liver atrophy (n = 1). Survival deteriorated with length of follow-up. There were three survivors from 34 patients treated in period I, 16 survivors from 81 patients treated in period II (three had LT), and 29 survivors from 48 patients treated in period III (11 had LT). CONCLUSIONS: Although satisfactory bile drainage can be obtained with portoenterostomy, our data suggest that liver function can deteriorate progressively, with a possible turning point in late adolescence, indicating that as the length of follow-up increases, clinical assessment should be regular and comprehensive. The timing of LT in postoperative BA patients with deteriorating liver function is a vital management issue.

Adolescent↗
PubMed1999

Laparoscopic extramucosal pyloromyotomy versus open pyloromyotomy for infantile hypertrophic pyloric stenosis: which is better?

BACKGROUND/PURPOSE: The aim of this study was to evaluate the advantages or disadvantages of laparoscopic pyloromyotomy compared with open transumbilical fold pyloromyotomy. METHODS: Thirty consecutive laparoscopic extramucosal pyloromyotomies (LP) performed from 1994 to 1997 were compared with 30 consecutive open pyloromyotomies (OP) performed during the same period with regard to age at operation, body weight, thickness of hypertrophied pyloric muscle, operating time, time of return to full feeding, frequency of postoperative emesis, surgical complications, and degree of surgical stress reflected by interleukin-6 (IL-6). LP was performed according to conventional techniques, and OP was performed using a transumbilical fold approach. RESULTS: The groups were matched for age at operation, preoperative clinical and physical status, laboratory data, and size of the hypertrophied pylorus assessed by ultrasonography. There was a learning curve with LP; the average operating time required for the first 10 cases was significantly longer than the time required for OP, but later cases took just as long as OP cases. Time taken to full feeding was significantly shorter in the LP group than the OP group (LP, 38 hours v OP, 64 hours). One case was converted from LP to OP because of mucosal perforation. The incidence of postoperative emesis was significantly higher in the OP group than in the LP group (OP, 25% v LP, 3%). The mean length of hospitalization was significantly shorter in LP (P < .01). The intraoperative peak values of IL-6 in LP were significantly lower than those in the OP group (P < .01). CONCLUSIONS: The advantages of LP are improved cosmesis, decreased surgical stress with earlier postoperative recovery, and shorter hospitalization. Because LP uses reusable devices, and the mean period of hospitalization is shorter, average operating costs could be reduced, representing a net saving in total hospital charges.

Eating↗
PubMed1999

Lack of C-KIT+ mast cells and the development of idiopathic gastric perforation in neonates.

BACKGROUND/PURPOSE: The proto-oncogene c-kit encodes a receptor tyrosine kinase C-KIT. W/Wv mice, which are devoid of C-KIT+ mast cells as a result of mutations in the c-kit gene, develop spontaneous gastric ulceration or perforation after day 7 of life at a high frequency, whereas normal litter mates do not. The authors hypothesized that a lack of C-KIT+ mast cells may be implicated in the development of idiopathic gastric perforation (GP) in neonates. METHODS: Postmortem gastric wall specimens were taken from neonates who died of GP (idiopathic, n = 6; secondary, n = 4), and other causes (controls, n = 6). Specimens were taken at random from various sites in the stomach and labeled with antibody to C-KIT. The number of C-KIT+ mast cells from five random fields per specimen were compared under light microscopy (200x). RESULTS: Overall, the number of C-KIT+ mast cells was significantly lower in gastric wall specimens from cases of idiopathic GP when compared with controls or cases of secondary GP irrespective of the sites of sampling (P<.01, analysis of variance test) with the distribution of cells being uniform and unique for each stomach. CONCLUSION: A lack of C-KIT+ mast cells may underlie the development of idiopathic GP in neonates.

Gastric Mucosa↗
PubMed1999

Hyaluronic acid: a specific prognostic indicator of hepatic damage in biliary atresia.

BACKGROUND/PURPOSE: Hepatic fibrosis can progress in biliary atresia (BA) and is associated with capillarization of hepatic sinusoids. The significance of serum hyaluronic acid (HA) as a noninvasive indicator of histological sinusoidal endothelial cell (SEC) damage and hepatic fibrosis in BA, is investigated. METHODS: A total of 28 postoperative BA patients (mean age, 11.0+/-3.7 years) and 20 normal controls (mean age, 10.5+/-2.8 years) were studied. BA patients were divided into group I, good liver function (n = 8); group II, moderate liver dysfunction (n = 10); and group III, severe liver dysfunction (n = 10). Serum HA was determined using a one-step sandwich enzyme immunoassay, and liver histological damage was confirmed immunohistochemically using an antibody against factor VIII-related antigen (FVIIIRAg), which is specific for detecting damaged SEC. RESULTS: Serum HA was significantly higher (P < .0001) in group III (84.6+/-36.5 ng/mL) than in group I (15.9+/-6.9 ng/mL) or group 11 (28.7+/-10.7 ng/mL). Although immunoreactive products of FVIIIRAg were abundant in group III, they were not detected in SEC from group II. CONCLUSION: Serum HA may be of value for monitoring postoperative BA patients as a noninvasive indicator of SEC damage and progressive hepatic fibrosis.

Adolescent↗