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Atsushi Imamura

Publications and source records attributed to Atsushi Imamura.

13 recordsLinked to original sources
PubMed2006

Recurrent hepatitis C after living donor liver transplantation detected by Tc-99m GSA liver scintigraphy.

Recurrence of hepatitis C virus (HCV) after living donor liver transplantation was investigated using technetium-99m- diethylenetriaminepentaacetic acid-galactosyl human serum albumin (Tc-99m-GSA) liver scintigraphy. Four patients with decompensated cirrhosis due to HCV infection were retrospectively reviewed in this study. Scintigraphy was performed to determine the hepatic uptake ratio of the tracer corrected for disappearance from the blood, as well as the maximal removal rate of the tracer by hepatocytes, as parameters of hepatic functional reserve. In all patients, serum HCV ribonucleic acid (RNA) was detected 3 months after transplantation. The corrected hepatic uptake ratio and removal rate showed little change after transplantation in two patients without the recurrence of HCV infection. In another two patients, these levels were decreased at 3 months after transplantation. In one patient, recurrent HCV infection was diagnosed by confirmatory histologic examination at 12 months after transplantation. In the other patient, both levels declined further at 8 months. Although treatment was initiated with a combination of interferon plus ribavirin, this patient died of progressive hepatic failure. In conclusion, a decrease in scintigraphic parameters at 3 months after transplantation suggests recurrent HCV infection affecting the graft. Tc-99m-GSA liver scintigraphy is a useful noninvasive method for evaluating graft functional reserve.

Female↗
PubMed2006

MR imaging and 1H-MR spectroscopy of a case of van der Knaap disease.

Van der Knaap disease, characterized by megalencephalic leukoencephalopathy and subcortical cysts, is a rare and recently defined condition. We discuss here the MR image (MRI) and MR spectroscopy (MRS) features in a 30-year-old man with S93L homozygous mutation in the MLC1 gene. MRI demonstrated high intensity diffuse white matter with T2-weighted image and subcortical cysts in the parietal and temporal lobes and MRS showed mildly reduced N-acetylaspartate (NAA) in areas of severe T2 elongation with a long TE sequence. A peak of lactate/lipid was indicated at a chemical shift of 1.3 ppm with a short TE sequence. The peak for myo-inositol was normal in areas of severe and mild T2 elongation with short TE MRS. These findings suggest that demyelination progresses slowly in van der Knaap disease and that MRS with long and short TE is useful for the evaluation of neural metabolization associated with van der Knaap disease.

Adult↗
PubMed2006

Agenesis of the gallbladder with hypoplastic cystic duct diagnosed at laparoscopy.

An 86-year-old man was admitted to our department with complaints of intermittent upper abdominal pain. Ultrasonography of the abdomen showed dilated extrahepatic bile ducts containing stones; however, the gallbladder was not clearly identified. Magnetic resonance cholangiopancreatography showed dilated extrahepatic ducts and choledocholithiasis without gallbladder visualization. The stone extraction was performed with endoscopic sphincterotomy. Three-dimensional images using spiral-computed tomography after intravenous-infusion cholangiography clearly demonstrated an obstruction of the cystic duct. The patient was scheduled for laparoscopic cholecystectomy. At laparoscopy, the gallbladder fossa was not identified on the undersurface of the liver. Despite a thorough examination of the intrahepatic (left-sided within the lesser omentum), retroperitoneal, retrohepatic (within the falciform ligament), retroduodenal, and retropancreatic areas using laparoscopic ultrasonography, the gallbladder was not found. After careful dissection of the hepatoduodenal ligament, the dilated extrahepatic bile duct and a 1-cm length of hypoplastic cystic duct were found. Gallbladder agenesis is usually accompanied by the lack of the cystic duct. The present case is the third report of gallbladder agenesis with a patent or hypoplastic cystic duct.

Abnormalities, Multiple↗
PubMed2005

Infrarenal abdominal aortic aneurysm complicated by persistent endotension after endovascular repair: report of a case.

Endoleak and endotension may prevent the successful exclusion of an aneurysm after endovascular aortic aneurysm repair (EVAR). The pressurization in the excluded aneurysm sac caused by endotension may lead to rupture of the aneurysm; however, the cause of endotension and its underlying mechanisms remain unclear. We report a case of infrarenal abdominal aortic aneurysm (AAA) complicated by persistent endotension after EVAR. Although no endoleaks were found on conventional double-phase computed tomographic scans, a thrombosed endoleak existed in the side branch and attachment site of the endograft. After treating the undetectable thrombosed endoleaks, physical examination revealed that the pressure of the excluded aneurysm had diminished, with shrinkage of the aneurysm. This case report suggests that a high-pressure undetectable type I or type II endoleak could be a major cause of endotension. Thus, postoperative evaluation of the attachment site of an endograft is important after EVAR.

Aged↗
PubMed2005

Serial MR imaging and 1H-MR spectroscopy of unidentified bright objects in a case of neurofibromatosis type 1.

Serial study using MR imaging and 1H-MR spectroscopy (1H-MRS) of unidentified bright objects (UBO) in a 9-year-old boy with neurofibromatosis type 1 (NF1) is described. UBO was indicated in the left globus pallidum at 3 years old, then appeared in the right globus pallidum at 5 years old along with left hemiconvulsion. These UBO gradually disappeared over several years. On 1H-MRS, the ratios of N-acetylaspartate (NAA)/creatine and that of choline/creatine were each mildly reduced in the UBO. These ratios improved in parallel with disappearance of the UBO. In addition, elevation of the lactate/lipid peak was shown in UBO during the early stage, however, it disappeared in the latter. The longitudinal follow-up using MR image and 1H-MRS was useful for metabolic evaluation of UBO in patients with NF1.

Brain↗
PubMed2005

Autoantibodies and cell-mediated autoimmunity to NMDA-type GluRepsilon2 in patients with Rasmussen's encephalitis and chronic progressive epilepsia partialis continua.

PURPOSE: To evaluate antibody-mediated and cytotoxic T cell-mediated pathogenicity that has been implicated as the autoimmune pathophysiological mechanism in Rasmussen's encephalitis. METHODS: We examined autoantibodies against the N-methyl-d-aspartate glutamate receptor (NMDA-type GluR) epsilon2 subunit and its epitopes in serum and CSF samples from 20 patients [five histologically proven (definitive) Rasmussen's encephalitis with epilepsia partialis continua (EPC), four definitive Rasmussen's encephalitis without EPC, and 11 clinical Rasmussen's encephalitis with EPC]. We examined 3H-thymidine uptake into lymphocytes after stimulation by GluRs. RESULTS: All nine definitive patients (five patients with EPC and four without EPC), and 10 of 11 clinical Rasmussen's encephalitis patients had the autoantibodies. In four patients, the autoantibodies were absent in early stage when epileptic seizures had already become frequent, and appeared subsequently. In two patients, the autoantibodies persisted in the serum after frontal lobe resection or functional hemispherectomy, although epileptic seizures were completely controlled. Autoantibodies to the C2 epitope predominated, while autoantibodies to the extracellular N epitope were rare. The mean 3H-thymidine uptake ratios (stimulation by GluRepsilon2-containing homogenates/stimulation by PHA) were significantly higher in definitive and clinical Rasmussen encephalitis patients than in controls. The mean 3H-thymidine uptake ratios (relative to PHA) were significantly higher for GluRepsilon2-containing homogenate than for control homogenate or GluRdelta2-containing homogenate. CONCLUSIONS: Autoantibodies against GluRepsilon2 may be one of the diagnostic markers for Rasmussen's encephalitis with and without EPC. Patients have activated T cells stimulated by GluRepsilon2 in peripheral blood circulation. We speculate that cellular autoimmunity and the subsequent humoral autoimmunity against GluRepsilon2 may contribute to the pathophysiological processes in Rasmussen's encephalitis.

Adolescent↗
PubMed2004

MR imaging and 1H-MR spectroscopy in a case of cerebral infarction with transient cerebral arteriopathy.

A case of cerebral infarction with transient cerebral arteriopathy in a 12-year-old female is described. The child showed with an acute onset of left hemiplegia, central facial palsy and aphasia. She was diagnosed with right internal carotid artery obstruction with no predisposing factors for cerebral infarction. A serial MR image and MR spectroscopy of the brain was performed. MR angiography revealed reversible vascular changes in the right middle cerebral artery after several months. The ratio of choline/creatine was elevated and that of N-acetylaspartate (NAA)/creatine was depressed in the cerebral lesion, however, they were normalized during the remission phase with long echo time-MR spectroscopy. The elevation of the lactate peak was clarified with short echo time-MR spectroscopy. The longitudinal follow up using MR angiography, and MR spectroscopy with long and short echo time was useful for the evaluation of reversible vascular change with cerebral infarction in children.

Aspartic Acid↗
PubMed2003

Laparoscopic treatment using an argon beam coagulator for nonparasitic liver cysts.

BACKGROUND: Laparoscopic deroofing has been shown to produce good patient satisfaction and to have results similar to those of open surgical techniques. We evaluated the feasibility and efficacy of laparoscopic deroofing using an argon beam coagulator (ABC) in the patients with nonparasitic liver cysts. METHODS: Laparoscopic deroofing for the treatment of liver cysts was attempted on 14 patients. After the deroofing, the secreting epithelium within the residual cystic cavity wall was destroyed using the ABC. RESULTS: Laparoscopic deroofing was successful in all patients. No deaths or surgical morbidity occurred, and no postoperative complications were recorded. The median postoperative hospital stay was 7 days. The median follow-up was 56 months for all patients, and all patients have remained completely asymptomatic for 6 months after the surgery, with no recurrence of the cysts. CONCLUSIONS: Our results indicate that laparoscopic deroofing using the ABC method in patients with nonparasitic liver cysts was effective in preventing cyst recurrence.

Aged↗
PubMed2003

Molecular genetic study in Japanese patients with Alexander disease: a novel mutation, R79L.

Since the first report by Brenner et al. of mutations in the glial fibrillary acidic protein (GFAP) gene in patients with Alexander disease, several molecular genetic studies have been performed in different ethnic groups. We previously reported a Japanese patient with a mutation, R239C, which is identical to one commonly found in American patients. Here we have analyzed four additional Japanese patients by screening for known mutations or, if no known mutation was found, by sequencing of all exons of the GFAP gene. We detected three missense mutations; one was a novel mutation, R79L, and two were previously reported mutations, R239C and R79C. All of our patients were heterozygous for their mutations. Together with the novel mutation, R79L, four different nucleotide changes altering the R79 residue have been reported, implying that any alternation of this arginine residue can give the GFAP protein a dominant negative effect, leading to accumulation of GFAP as Rosenthal fibers. We conclude that molecular genetic analysis of the GFAP gene is feasible for antemortem diagnosis of Alexander disease in Japanese patients.

Alexander Disease↗
PubMed2002

MR imaging and 1H-MR spectroscopy in a case of juvenile Alexander disease.

The serial MR image and MR spectroscopy in the brain were examined in a young male diagnosed as having juvenile Alexander disease. He had megalencephaly, psychomotor retardation, seizures, and increasing elevation of increasing alpha-B crystallin and heat shock protein 27 in the cerebrospinal fluid. Serial MR images demonstrated increased demyelination of the bilateral frontal region to left occipital region over several years. The myo-inositol/creatine ratio was significantly increased in both the demyelinated white matter and normal area in the MR spectroscopy. These results suggested that demyelination very slowly progressed from the frontal to occipital region and that glial degeneration may occur even in the unaffected white matter of patients with juvenile Alexander disease.

Adolescent↗
PubMedDate not supplied

Vaccination and infection as causative factors in Japanese patients with Rasmussen syndrome: molecular mimicry and HLA class I.

Rasmussen syndrome is an intractable epilepsy with a putative causal relation with cellular and humoral autoimmunity. Almost half of the patients have some preceding causative factors, with infections found in 38.2%, vaccinations in 5.9% and head trauma in 8.9% of Japanese patients. In a patient with seizure onset after influenza A infections, cross-reaction of the patient's lymphocytes with GluR epsilon 2 and influenza vaccine components was demonstrated by lymphocyte stimulation test. Database analyses revealed that influenza A virus hemagglutinin and GluR epsilon 2 molecules contain peptides with the patient's HLA class I binding motif (HLA - A*0201). The relative risks of HLA class I genotypes for Rasmussen syndrome are 6.1 (A*2402), 6.4 (A*0201), 6.3 (A*2601) and 11.4 (B*4601). The relative risks of HLA class I-A and B haplotypes are infinity (A*2601 + B*5401), 21.1 (A*2402 + B*1501), 13.3 (A*2402 + B*4801) and 5.1 (A*2402 + B*5201). Some alleles and haplotypes of HLA class I may be the risk factors in Japanese patients. Cross-reactivity of cytotoxic T lymphocytes may contribute to the processes leading from infection to the involvement of CNS.

Encephalitis↗