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Biomedical subjects

A Yamataka

Publications and source records attributed to A Yamataka.

At least 73 records · Page 4Linked to original sources
PubMed1996

Pancreaticobiliary maljunction associated with nondilatation or minimal dilatation of the common bile duct in children: diagnosis and treatment.

It is known that the etiology of congenital biliary dilatation (CBD) is closely associated with pancreaticobiliary maljunction (PBMJ). Treatment of CBD today is primary excision of the cyst followed by hepaticoenterostomy. However, PBMJ without dilatation of the biliary tract has recently been reported and its treatment is still controversial. In adults, simple cholecystectomy without biliary reconstruction is often performed, because it usually presents as an anomaly of the gallbladder. Over 30 years, we have encountered 8 patients with PBMJ without dilatation of the common bile duct in 180 pediatric cases of CBD. The presenting symptoms of these patients were those of pancreatitis i.e. abdominal pain associated with elevation of serum amylase levels. Five cases presented with jaundice or a history of pale colored stools. Endoscopic retrograde cholangiopancreatography was performed to confirm the diagnosis. Five (62.5%) of these 8 patients were found to have dilatation of the common channel, which was seen in 50 (29%) of the 172 other cases with biliary tract dilatation. Three cases (37.5%) had proven protein plugs or debris at the level of the common channel, and this was observed in 28 (16%) of the 172 other cases. It is strongly suggested that the manifestation of clinical symptoms in these patients results from stasis or obstruction at the level of the common channel. In children who present with recurrent pancreatitis, PBMJ must be suspected even if the common bile duct appears to be normal. It is difficult to resolve these anomalies without operative repair. The authors consider that radical treatment of PBMJ is required in these children to prevent serious long-term complications.

Abdominal Pain↗
PubMed1996

Specific acceptance of fetal bowel allograft in mice after combined treatment with anti-intercellular adhesion molecule-1 and leukocyte function-associated antigen-1 antibodies.

OBJECTIVE: The aim of this study was to see whether tolerance could be induced by simultaneous administration of monoclonal antibodies (MoAbs) to intercellular adhesion molecule-1 (ICAM-1) and leukocyte function-associated antigen-1 (LFA-1) after transplantation of fetal small bowel between fully incompatible mice strains. METHODS: Fetal small bowel from either BALB/c (H-2d) or C3H/He (H-2k) mice was transplanted into the space between the peritoneum and rectus abdominis of adult C3H/He recipient mice. Syngeneic (n = 6) and two allogeneic transplant groups were made. In one of the allogeneic groups (n = 8), no immunosuppressant was given. In the other allogeneic group (n = 13), both anti-LFA-1 and anti-ICAM-1 MoAbs (50 micrograms each/mouse/day) were given intraperitoneally after transplantation for the first 4 weeks. In the syngeneic and untreated allogeneic groups, all mice were killed 4 weeks after transplantation. In the treated allogeneic group, eight mice were killed 6 weeks after cessation of the MoAb treatment. At the time the mice were killed, the bowel graft as well as the recipient spleen were taken for histologic analysis and cytotoxic T-lymphocyte (CTL) assay, respectively. Each mouse in the remaining treated five mice was transplanted with BALB/c and C57BL/6 (as third-party) full-thickness skin simultaneously 8 weeks after cessation of the MoAb treatment. RESULTS: All grafts in the syngeneic group survived with normally developing villi, whereas all grafts in the untreated allogeneic group disappeared. In the treated allogeneic group, all allografts developed normal mucosa without any sign of rejection. Splenocytes from the recipient mice in the untreated allogeneic group showed increased CTL induction against donor-type alloantigen (p < 0.005), compared with that in the syngeneic group. Suppressed CTL induction against donor-type alloantigen was observed in the treated allografted recipient (p < 0.001), whereas CTL induction against third-party alloantigen was intact (p = NS). Third-party skin graft was normally rejected within 10 days, whereas donor-type skin graft was accepted in all mice tested. CONCLUSIONS: Specific tolerance for fetal bowel allografts could be induced by a relatively short-term treatment with anti-ICAM-1 and anti-LFA-1 MoAbs. This mode of immunointervention could perhaps be applied to humans undergoing small-bowel transplantation.

Animals↗
PubMed1996

Masked ureteral duplication with ectopic ureter detected by magnetic resonance imaging.

The usefulness of magnetic resonance imaging (MRI) in the detection of a masked duplex kidney system is described. A 9 year old girl was admitted to our hospital for urinary incontinence. She was found to possess an ectopic ureter associated with complete ureteral duplication. She had been evaluated for incontinence at several hospitals, but neither ultrasound sonography nor intravenous pyelography detected any abnormalities. Only cystoscopic examination and MRI detected the anomalies. Partial nephroureterectomy resolved the patient's incontinence. MRI is useful for the detection of ureteral duplication and should be used on cases in which this condition is suspected, prior to performing invasive procedures.

Child↗
PubMed1996

[Surgical strategy for the treatment of congenital biliary dilatation based on the location of intrahepatic bile duct dilatation].

Congenital biliary dilatation used to be regarded as having a good prognosis. However, some recent long-term follow-up studies have shown there to be quite a high incidence of postoperative intrahepatic bile duct (IHBD) stone formation. In most of the cases in whom IHBD stones form, the IHBD were found to be dilated as the time of initial surgery. Therefore, preoperative evaluation of IHBD dilatation using various imaging studies is extremely important. Surgically, in cases involving structure of the common hepatic duct (CHD) with dilatation above the structure, resection of the stricture and a wide hepaticointestinal anastomosis are strongly recommended. In cases where there is a stricture of the CHD or of the first branch of the IHBD, a reconstructive technique should be applied to dilate the stricture. Patients who have a structure and cystic dilatation of the IHBD above the second branch should be carefully followed-up postoperatively. Partial liver resection to remove the cyst may be required at the time of initial operation or at a later stage.

Bile Ducts, Intrahepatic↗
PubMed1995

A lack of intestinal pacemaker (c-kit) in aganglionic bowel of patients with Hirschsprung's disease.

Recent experimental studies in mice have shown that the proto-oncogene c-kit plays a key role in the development of a component of the pacemaker system that is required for generation of autonomic gut motility. These studies further suggest that interaction of the c-kit receptor and its ligand (stem cell factor, SCF) is critical for the development of the enteric nervous system. The authors investigated the presence of c-kit-positive (c-kit+) cells as well as the expression of SCF in bowel from 12 patients with Hirschsprung's disease (HD), 4 patients with total colonic aganglionosis (TCA), 2 patients with extensive aganglionosis (EA) and 14 controls. Our methods involved the use of immunohistochemistry with antihuman c-kit sera and antihuman SCF sera. A few c-kit+ cells were found in the muscle layers of aganglionic bowels from HD, TCA and EA, in contrast to many c-kit+ cells in ganglionic bowel segments from control, HD, and TCA patients. Expression of SCF was identified in the muscle layers as well as in myenteric plexus of ganglionic bowel, in contrast to its absence in the muscle layers of aganglionic bowel specimens. A lack of c-kit and SCF might be of significance for autonomic gut dysmotility in aganglionic bowel segments of patients with HD and allied disorders such as chronic idiopathic intestinal pseudo-obstruction.

Cell Adhesion Molecules↗
PubMed1995

Choledochal cysts: special emphasis on the usefulness of intraoperative endoscopy.

Long-term complications after excisional surgery for choledochal cyst include stone formation within the intrahepatic bile duct (IHBD) and within the intrapancreatic portion of the bile duct (IPBD). The authors reviewed 180 patients with choledochal cysts (137 women) seen during a 30-year period and report their recent experience with intraoperative cyst endoscopy. Primary cyst excision with hepaticoenterostomy was performed in 150 cases, and a secondary cyst excision, after various lesser drainage procedures, in 24. Six children were treated early in the series with a cyst enterostomy. The mean age and follow-up period were 4.3 and 9.4 years, respectively. At surgery, dilatation of the IHBD was identified in 96 patients, and protein plugs or stones were observed in 31 common pancreaticobiliary channels. Fifty-five common channels were noted to be dilated. Hepaticojejunostomy was performed in 123 patients without intraoperative endoscopy. Late stone formation occurred within the IHBD in 4 of these cases and within residual segments of intrapancreatic cyst in 2 (mean age and follow-up period were 4.9 and 13.0 years, respectively). Intraoperative endoscopy was performed in 51 patients (mean age and follow-up period 3.6 and 4.3 years), and stone formation has not been observed in any patients in this group. Intraoperative cyst endoscopy is recommended as a valuable adjunct to choledochal cyst excision.

Adolescent↗
PubMed1995

Prevention of fetal bowel allograft rejection by combined treatment with anti-ICAM-1 and anti-LFA-1 antibodies.

Prevention and treatment of allograft rejection remain the major issues in clinical small bowel transplantation. New strategies for manipulating immune responses using more powerful immunosuppressive agents continue to be evaluated. The fetal small bowel from BALB/c (H-2d) or C3H/He (H-2k) mice was transplanted into the space between the peritoneum and rectus abdominis of adult C3H/He (H-2k) recipient mice. Syngeneic (n = 6) and allogeneic transplant groups were made. In the allogeneic group, the recipient mice were subdivided into three groups, depending on the duration of combined treatment with anti-LFA-1 and anti-ICAM-1 monoclonal antibodies (MAbs): untreated (n = 10), 7-day course (n = 10), and 4-week course (n = 14). A dose of 50 micrograms/mouse/d each of both MAbs was given intraperitoneally, immediately after transplantation and on the consecutive days. All mice were killed 4 weeks after transplantation, and the graft as well as the recipient spleen were taken for histological examination, graft survival ratio, mixed lymphocyte reaction (MLR) assay and cytotoxic T lymphocyte (CTL) assay. All grafts in the syngeneic group survived with normal villi, whereas all grafts in the allogeneic group without treatment disappeared within 4 weeks. All grafts in the allogeneic group with a 7-day course of MAb treatment showed marked disruption of the mucosa with massive cellular infiltration. However, in the allogeneic group treated for 4 weeks, all allografts had adequate growth and demonstrated normal villi with minimal cellular infiltration. Splenocytes from allografted recipient mice without MAb treatment showed markedly increased MLR and CTL activity, compared with the activity seen in the syngeneic MLR and CTL.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Quantitative analysis of neuronal innervation in the aganglionic bowel of patients with Hirschsprung's disease.

Although there is marked proliferation of nerve fibers in the aganglionic bowel of patients with Hirschsprung's disease (HD), controversy exists as to whether these fibers terminate in the cells of the bowel wall. This study quantitates biochemically the synaptic vesicle proteins and neurofilaments in the aganglionic bowel of HD patients. The bowel specimens obtained from 12 patients with HD (mean age, 4.6 months) and nine age-matched controls were analyzed by Western blot analysis using monoclonal antibody 171B5 against the synaptic vesicle 38,000-d protein (SVP38), and the specific band obtained was quantitated by densitometry. Similarly, using monoclonal antibody NF70K for detecting the 70,000-d component of neurofilament (NF70), nerve fibers were quantitated. In the aganglionic HD bowel, the quantity of SVP38, representing a proportion of synapses, was significantly lower than that in the normoganglionic bowel (P < .001). The quantity of NF70, representing a proportion of nerve fibers, was significantly greater than that in the normoganglionic bowel (P < .05). These findings suggest that the nerve fibers in the aganglionic bowel of HD patients have much less developed connections with the cells of the bowel wall, indicating overall poor innervation, despite marked proliferation of the nerve fibers.

Blotting, Western↗
PubMed1994

Indwelling mesenteric venous catheterization for early detection of portal vein thrombosis: possible application to pediatric liver transplantation.

Portal vein thrombosis (PVT) is a well-recognized complication after liver transplantation, particularly in children. When it occurs early in the postoperative period, it has serious consequences, and rapid detection is essential. The purposes of this study were (1) to ascertain whether continuous monitoring of mesenteric venous pressure (MVP), via an indwelling mesenteric venous catheter, could assist in early detection of PVT and (2) to investigate the role of portography, via the catheter, in confirming this complication. An animal model of PVT was developed in pigs. At laparotomy, a heparin-coated catheter was inserted into a jejunal mesenteric vein, delivered percutaneously and connected to a pressure transducer. Conditions of PVT were simulated by progressive occlusion of the portal vein (PV) using a silastic tourniquet, and the degree of PV stenosis was assessed by Doppler ultrasound flow-velocity measurement. MVP was recorded 1 and 3 minutes after PV occlusion, and portography was performed via the indwelling catheter. There were significant increases in MVPs with all degrees of PV stenosis (P < .01, Student's t test). No significant changes in MVP were noted between 1 and 3 minutes postocclusion. Portography clearly demonstrated PV stenosis. There were no instances of PVT, despite repeated and prolonged occlusion of the PV. Progressive degrees of PV stenosis have been clearly detected by an indwelling mesenteric venous catheter in an animal model. This method may be useful for the diagnosis and treatment of PVT after pediatric liver transplantation.

Animals↗
PubMed1994

Tubed latissimus dorsi musculocutaneous flaps for thoracic esophageal replacement: an experimental study.

Tubed musculocutaneous flap has never been used to replace a circumferential defect of the thoracic esophagus in adults or children. The aim of this study was to examine whether a tubed latissimus dorsi musculocutaneous flap (TLDMF) can be used to repair a long gap defect of the thoracic esophagus. In 14 puppies with an average weight of 4.9 kg, part of the esophagus (two vertebrae in length) was excised through a right thoracotomy. A latissimus dorsi musculocutaneous flap was introduced into the thoracic cavity. The cutaneous layer was rolled into a tube and interposed in the space of the excised esophagus. The muscle layer was wrapped around the anastomosis. Three puppies died of operative complications, such as a minor anastomotic leakage and postoperative bleeding. One died of an unknown cause. Ten puppies were studied postoperatively with a barium meal, endoscopic examination, and autopsy. The management of these puppies over 4 months is described. It proved possible to replace a long gap thoracic esophageal defect with a TLDMF, which was safe, easy to be transferred, and obviated a laparotomy. Thus, this technique might offer an alternative method to bridge a long gap in patients with esophageal atresia or severe stenosis.

Animals↗
PubMed1994

Abnormal distribution of nerve terminals in infantile hypertrophic pyloric stenosis.

Smooth muscle biopsy specimens obtained from nine infants with infantile hypertrophic pyloric stenosis (IHPS) and from three controls were studied immunohistochemically with respect to the distribution of nerve terminals and neurofilaments. To label nerve terminals and neurofilaments, monoclonal antibodies (MAb) 171B5 and 2F11 were used, respectively. In all specimens of the control group, nerve terminals were numerous in both the myenteric plexus and the muscle layer. There were abundant neurofilaments in the myenteric plexus and a moderate number in the muscle layer. In all specimens of the IHPS group, the density of nerve terminals and neurofilaments was reduced in the muscle layer. In the myenteric plexus, there was no such reduction. The results indicate poor neuronal innervation of the muscle layer in the pylorus of infants with IHPS. This poor innervation may be related to the pathogenesis of pyloric stenosis and hypertrophy.

Antibodies, Monoclonal↗
PubMed1993

Ultrastructural changes in the microvilli as a marker of small bowel rejection.

Small bowel rejection occurs in patches; therefore, to detect bowel rejection in situations where a stomal biopsy appears normal under the light microscope, we studied the ultrastructural changes in bowel microvilli following heterotopic small bowel transplantation in rats. Thin sections of bowel biopsy specimens, which appeared normal under a light microscope, were selected and examined under an electron microscope for microvillous changes. Microvillous changes were seen in both the syngeneic and allogeneic groups on the 2nd and 4th postoperative days, but these changes were absent in the syngeneic group by the 8th postoperative day, although they were still detected in the allogeneic group. Thus, following small bowel transplantation, electron microscopic analysis is recommended to confirm rejection with a patchy distribution after the 8th postoperative day.

Animals↗