Biomedical subjects

Shinji Yamamoto

Publications and source records attributed to Shinji Yamamoto.

42 records · Page 3Linked to original sources

PubMed2002

Characterization of autoantibodies to ferritin in canine serum.

Ferritin-binding proteins circulating in mammalian blood are thought to be involved in the clearance of ferritin. The present study characterizes canine serum autoantibodies (IgM and IgA) that react with ferritin. Canine IgM and IgA bound to bovine spleen ferritin as well as canine liver ferritin. To examine the specificity of canine IgM and IgA to ferritin H and L subunits, we used canine heart ferritin and canine liver ferritin with H/L subunit ratios of 3.69 and 0.43, respectively. Canine IgM and IgA recognized both of the H- and L-subunit-rich isoferritins, showing that their binding activities to ferritin depend on the H-subunit content. Recombinant bovine H-chain ferritin homopolymer expressed in a baculovirus expression system bound more with IgM and IgA than the recombinant L-chain homopolymer expressed under the same conditions. These results suggest that canine IgM and IgA recognize H-subunit-rich isoferritins, and that H-subunit-rich isoferritins are cleared from the circulation more rapidly than L-subunit-rich isoferritins.

Animals↗

PubMed2002

The impact of obesity in renal transplantation: an analysis of paired cadaver kidneys.

BACKGROUND: Previous studies indicate that obesity is a risk factor in renal transplantation. However, these analyses did not control for variable donor factors that may strongly influence outcome. To control for donor variables such as age, cause of death, procurement techniques, preservation methods, cold ischaemia time and implantation technique, we analysed patient and graft survival in recipients of paired kidneys, derived from the same procurement procedure, preserved in the same manner, subjected to similar cold ischaemia time and implanted by the same surgical team. Between June 1992 and August 1999, 28 procurement procedures provided kidneys which were transplanted into one obese and one non-obese recipient. Body mass index (BMI) was calculated as kg/m2. Recipients were classified as obese (BMI > 30) or non-obese (BMI < 30). Immunotherapy for all recipients consisted of a triple therapy regimen of cyclosporine or prograf, azathioprine or cellcept, and prednisone. Patients with delayed graft function (DGF), defined as the need for dialysis within 72 h of the transplant procedure, were treated with anti-thymocyte globulin (ATG) or thymoglobulin (TMG) induction for 5-7 d. The rate of DGF (7.1 versus 10.7%) and acute rejection (39.3 versus 35.7%) were similar in the obese and non-obese recipient groups. Patient survival was similar at 1, 3 and 5 yr in both groups. In addition, graft survival was similar at 1 yr. However, a trend toward decreased medium-term graft survival, which reached significance at 5 yr, was observed in the obese group. Furthermore, mean serum creatinine at 1 yr was higher in the obese group (2.0) compared with the non-obese group (1, 4) (p=0.12). This analysis of paired cadaver kidneys indicated that obesity is not a risk factor for DGF, acute rejection, and 1-yr graft survival. However, a decreased medium- and long-term graft survival trend, which reached statistical significance at 5 yr, was observed in obese recipients.

Adult↗

PubMed2002

Spontaneous intracerebral hematomas expanding during the early stages of hemorrhage without rebleeding. Report of three cases.

Expansion of intracerebral hematoma usually occurs in the chronic phase because of repeated bleeding from pre-existing vascular anomalies or exudation of blood from capillaries of the capsule. In contrast, spontaneous intracerebral hematoma expanding during the acute phase of hemorrhage without rebleeding is seldom seen. Three such cases are reported, along with magnetic resonance (MR) and computerized tomography (CT) follow-up studies. The follow-up MR images and CT scans demonstrated no evidence of rebleeding, but revealed gradual expansion of a fluid component of the hematoma, beginning in the acute phase. Volume alterations posthemorrhage are carefully documented. There was a characteristic phenomenon of layering, with the red blood cell component of the clot settling by gravity and the serum separating as well as seen in a test tube, depending on whether a preservative was used. Examination of blood samples indicated a possible correlation between expansion of the hematoma and the activities of both the fibrinolytic system and coagulation factors.

Acute Disease↗

PubMed2002

Reduced transduction efficiency of adenoviral vectors expressing human p53 gene by repeated transduction into glioma cells in vitro.

PURPOSE: Recombinant adenoviral vectors are widely used in clinical and experimental studies to treat malignant tumors. Recently, host immune responses have been proposed as a major limitation in using adenoviral vectors for repeated gene delivery. We demonstrate another limitation unrelated to host immunity. EXPERIMENTAL DESIGN: We repeatedly transduced an adenoviral vector expressing the human p53 gene (AxCIhp53) into U373MG, a p53-susceptible cell line, and established the AxCIhp53-resistant cell line U373R. Most U373R cells survived even after AxCIhp53 treatment due to reduced transduction efficiency. Expression levels of adenovirus receptors were estimated to investigate the cause of reduced transduction efficiency. The mutant vector was used to overcome the resistance. RESULTS: The transduction efficiency of an adenoviral vector possessing the reporter LacZ gene (AxCAZ2-F/wt) for U373R cells was 25.4-fold less than that for parent cells. The expression levels of integrins alpha(v)beta(3) and alpha(v)beta(5) were found to be decreased in U373R cells without affecting the expression levels of Coxsackievirus and adenovirus receptor. The mutant vector AxCAZ2-F/K20, with a linker and a stretch of 20 lysine residues at the COOH-terminal of the fiber protein, improved the transduction efficiency of U373R cells to 12.6-fold of that of AxCAZ2-F/wt. A mutant vector carrying the p53 gene, AxCAhp53-F/K20, dramatically induced apoptosis in U373R cells. CONCLUSIONS: Glioma cells expressing low levels of adenovirus receptors might survive and proliferate to recur after repeated adenoviral transduction, even if the adenoviral transduction is effective at first. Changing the tropism of vectors is a potent method to overcome resistance.

Adenoviridae↗

PubMed2001

Calcific deposits on degraded shunt catheters: long-term follow-up of V-P shunts and late complications in three cases.

OBJECT: Three cases with late complications and nine cases without late complications are presented to demonstrate the long-term results of ventriculoperitoneal (V-P) shunting, particularly those concerning degradation and mineral deposits of shunt catheters. METHODS: Plain X-rays were taken in every case to detect any calcification. The catheters removed following late complications were examined in a scanning electron microscope (SEM). Spectroscopy and conventional histology were also performed. CONCLUSION: Routine histology, spectroscopy, and SEM revealed that the mineral deposits consisted of hydroxyapatite. Plain X-ray and operative findings showed that the most extensive calcification was present in the neck, where the catheters were subject to heavy mechanical stress. No calcification was detected on catheters that did not contain barium particles. Our findings indicate that mechanical stress contributes to the process of degradation, and that barium sulfate admixed with silicone during the manufacturing process might accelerate late complications owing to the formation of cracks in the catheters and by enhancing the nucleation rate.

Adolescent↗

PubMedDate not supplied

[A case of adult-onset Huntington disease presenting with spasticity and cerebellar ataxia, mimicking spinocerebellar degeneration].

We report an adult-onset case of Huntington disease presenting with spasticity and cerebellar ataxia. The patient, a 47-year old woman, was admitted to our clinic because of progressive involuntary movements. Her elder brother suffered from the similar symptoms. Neurologically, she had quick temper, dementia, generalized chorea, spasticity and truncal ataxia. MRI demonstrated atrophy of caudate, midbrain, pons and cerebellum. From these clinical and MRI findings, she was suspected to have a form of spinocerebellar degeneration (SCD), particularly DRPLA. However, DNA analysis showed CAG repeats in huntington gene was expanded (47/20). Accordingly she was diagnosed as having adult-onset Huntington disease, mimicking SCD. This case indicates Huntington disease may present atypical clinical features and it is crucial to determine CAG repeat size in huntington gene for the patient with dementia and/or movement disorders, etiology of which is unknown. The relationships between clinical phenotypic variations and huntington gene expression are not determined.

Cerebellar Ataxia↗