Biomedical subjects

K Masuda

Publications and source records attributed to K Masuda.

At least 199 records · Page 11Linked to original sources

PubMed1998

Abscess formation as a complication caused by postoperative osteomyelitis of the femur.

We report an unusual case of a giant femoral abscess caused by postoperative osteomyelitis after treating a fracture of the femoral shaft. The patient ignored it until the abscess began to interfere with knee flexion, but no symptoms of inflammation such as fever, pain or abnormal laboratory values were found. Within the marrow cavity, many plasma cells produced immunoglobulins G and M, and the level of these substances in the abscess fluid connected to the bony focus were higher than the serum levels. It was concluded that the inflammation in this case signified a peculiarity in a primarily chronic process.

Abscess↗

PubMed1998

Twenty-five types of T-cell receptor Vbeta family repertoire in patients with Kawasaki syndrome.

UNLABELLED: Recently, a possible relationship between Kawasaki syndrome (KS) and superantigen has been discussed since the report of selective expansion of specific Vbeta family in the acute phase of KS. To further investigate the relationship between KS and superantigens, we examined 25 types of T-cell receptor Vbeta family repertoire in patients with KS using the reverse transcription polymerase chain reaction. This is the first attempt to examine all of 25 Vbeta families in KS. A non radioisotope method was used to quantify mRNA so that the experiment was safer, simpler, and faster. An expression index (EI) for each Vbeta was defined as: (the amount of each Vbeta mRNA)/(the sum of all Vbeta mRNA) x 100. Ten patients with KS and ten normal children were studied. The Vbeta9 and Vbeta15 of acute phase of KS showed both significantly lower mean EI and significantly higher frequency of a decreased EI value as compared with control children. Selective expansion of the Vbeta family in the patients with KS was not observed. Although highly increased EIs were observed in various Vbetas, their frequency was not statistically significant. The pattern of increased Vbetas did not show the specific pattern that indicates a particular superantigen. CONCLUSION: In Kawasaki syndrome non-radioisotope method for analysing Vbeta mRNA is useful in cases where many samples have to be handled. The depletion of Vbeta9 and Vbeta15 or highly increased expression index in the acute phase of Kawasaki syndrome might suggest a relationship to superantigens.

Bacterial Toxins↗

PubMed1998

N-glycan structures of a recombinant mouse soluble Fcgamma receptor II.

N-glycans of a recombinant mouse soluble Fcgamma receptor II (sFcgammaRII) expressed in baby hamster kidney cells were released from glycopeptides by digestion with glycoamidase A (from sweet almond), and the reducing ends of the oligosaccharides were reductively aminated with 2-aminopyridine. The derivatized N-glycans were separated and structurally identified by a three-dimensional high-performance liquid chromatography (HPLC) mapping technique on three kinds of HPLC columns [Takahashi, et al. (1995) Anal. Biochem. 226:139-46]. Eighteen different major N-glycan structures were identified, of which six were neutral (45%), five mono-sialyl (49%), one di-sialyl (4.6%), five tri-sialyl (1.1%), and one tetra-sialyl (0.3%). All N-glycan structures determined were complex type with fucosylation at the N-acetylglucosamine residue of the reducing end, and N-acetylneuraminic acid, when present, was alpha-(2,3)-linked. The existence of a unique structure containing both N-acetylgalactosamine and alpha-(2,3)-N-acetylneuraminic acid residues at the reducing ends, as below, was confirmed by MALDI-TOF mass spectrometry. Carbohydrate sequence [see text]

Animals↗

PubMed1998

Endotoxin removal column containing polymyxin B immobilized fiber is useful for the treatment of the patient with Vibrio vulnificus septicemia.

A case of primary septicemia due to Vibrio vulnificus infection is reported. The patient was successfully treated with appropriate antibiotic therapy, drainage, and debridement of the necrotic tissues and direct hemoperfusion (DHP) using polymyxin B immobilized fiber (PMX-F). The effectiveness of DHP using PMX-F, which removes endotoxin in the circulating blood for the treatment of septic shock and multiple organ dysfunction occurring due to this fulminant infectious disease, is discussed.

Anti-Bacterial Agents↗

PubMed1998

Inflammatory reaction via arachidonic acid cascade after intravitreal injection of endothelin-1.

PURPOSE: To investigate the characteristics of anterior chamber inflammatory reaction induced by intravitreal injection of endothelin-1 (ET-1). METHODS: The time course of changes in aqueous protein concentration (APC) after intravitreal injection of 10(-4), 10(-5), 10(-6) and 10(-7) M ET-1 into rabbit eyes was measured with a laser flare-cell meter. The influence of a topical diclofenac sodium (DFNa) pre- and post-treatment was assessed. Aqueous prostaglandin E2 and leukotriene B4 concentration was quantified using a radioimmunoassay technique. RESULTS: Intravitreal injection of 10(-4) and 10(-5) M ET-1 significantly increased APC, while 10(-6) and 10(-7) M ET-1 did not induce anterior chamber inflammation. After 10(-5) M ET-1 injection, APC reached a maximum at 4 h post-treatment and returned to a normal level 48 h after injection. Eyes treated with 10(-4) M ET-1 displayed a bi-phasic time course, with peak values observed 4 to 8 h as well as 48 h after administration. Pre- and post-treatment with topical DFNa completely suppressed the APC increase in the 10(-5) M ET-1 preparation, and considerably inhibited it in the 10(-4) M ET-1 preparation. After ET-1 injection, aqueous prostaglandin E2 concentration increased significantly, followed by an increase in APC. There were no changes in leukotriene B4 concentration. CONCLUSIONS: ET-1 induces anterior chamber inflammation via the cyclooxygenase pathway of the arachidonic acid cascade. The lipoxygenase pathway is not involved in this reaction.

Administration, Topical↗

PubMed1998

Advance in the diagnosis of esophageal carcinoma. A new imaging process by adaptive spatial filtering of computed esophagograms.

PURPOSE: To assess the clinical utility of computed radiographic images processed with adaptive spatial filtering (ASF) in the diagnosis of esophageal carcinoma. MATERIAL AND METHODS: After determining the optimal values for ASF image parameters in double-contrast barium studies, we used ASF to process the esophagograms of 35 patients with 37 esophageal carcinomas (superficial 20, advanced 17). The image quality of each lesion was evaluated independently by four radiologists on the basis of detectability, extent, and surface structure. The scoring was: 1 when the ASF image was superior to the original; -1 when the converse was true; and 0 when quality of images was equal. RESULTS: In superficial carcinoma, the mean scores for image quality with regard to detectability, extent, and surface structure were 0.19, 0.48, and 0.31 respectively. In advanced carcinoma, the scores were 0.00, 0.76, and 0.25 respectively. CONCLUSION: ASF offers an improved image quality which is valuable in the evaluation of esophageal carcinoma, particularly in the detection of superficial carcinomas and in the identification of intraepithelial extension.

Barium Sulfate↗

PubMed1998

Early esophageal carcinoma. Evaluation of the depth of invasion based on double-contrast esophagography.

PURPOSE: The aim of this study was to assess the depth of invasion of early esophageal carcinoma (EEC) by means of double-contrast esophagography. MATERIAL AND METHODS: The radiological findings of 46 EECs were retrospectively analyzed for the following factors that might be related to the depth of invasion: in depressed lesions (n = 30): maximum size, surface appearance, sharpness of contour, and wall rigidity; and in elevated lesions (n = 16): maximum size, height, shape, and wall rigidity. All lesions were surgically or endoscopically resected and the radiological findings were compared with the histological appearance. RESULTS: In depressed lesions, the size of the surface granules correlated very strongly with the depth of invasion (rs = 0.8147). In both depressed and elevated lesions, wall rigidity correlated strongly with the depth of invasion (rs = 0.7540 and rs = 0.6702 respectively). In depressed lesions, sharpness of contour also correlated strongly with the depth of invasion (rs = 0.6731). The other factors did not correlate with the depth of invasion. CONCLUSION: Double-contrast esophagography could provide useful information for assessing the depth of invasion of EECs.

Barium Sulfate↗

PubMed1998

Patterns of care study of radiation therapy for esophageal cancer in Japan: influence of the stratification of institution on the process.

BACKGROUND: To improve the quality of radiation therapy in Japan, Patterns of Care Study (PCS), a widely known QA program in the USA, was introduced in Japan. The feasibility was tested by collecting nationwide data by extramural audit for esophageal cancer. METHODS: From July 1996 through February 1997, PCS audits were performed for 29 institutions. Based on the facility survey by Tsunemoto, 13 institutes were classified as A1 (university hospital/cancer center treating > 300 patients/year), 10 as B1 (other institutes > 120 patients/year) and six as B2 (other institutes < 120 patients/year). Medical charts for 455 patients with thoracic esophageal cancer between 1992 and 1994 were reviewed based on the data format of PCS in the USA. RESULTS: Concerning external beam equipment, linear accelerators of > or = 10 MV were used for 73% of patients in A1, whereas in B1-2, 60Co machines were still used for 13% of patients (P < 0.0001). The median number of full-time equivalent (FTE) radiation oncologists was 2.7 in A1, 0.65 in B1 and 0.2 in B2. Forty-five percent of patients had received surgery in A1 and 34% in B1-2 (P = 0.0068). In the non-surgery group, a higher radiation dose of > 60 Gy was delivered in A1 than in B1-2 (P = 0.0008). Chemotherapy was administered to 51% of the patients in A1 and to 30% in B1-2 (P < 0.0001). Brachytherapy was utilized for 17% in A1 and only for 5% in B1-2 (P = 0.0001). CONCLUSION: Institutional stratification, including equipment and personnel, significantly affected the patterns of care for esophageal cancer. Therefore, to improve the quality of radiation therapy nationwide, improvement of equipment and supply of FTE personnel is extremely important. PCS was found to have great potential for the practical evaluation of how much will be required in Japan.

Adult↗

PubMed1998

Optimal MR cholangiopancreatographic sequence and its clinical application.

PURPOSE: To determine the appropriate acquisition parameters for magnetic resonance cholangiopancreatography (MRCP) with a half-Fourier rapid acquisition with relaxation enhancement (RARE) sequence; to determine the optimal MRCP technique by comparing half-Fourier RARE, steady-state free precession (SSFP) two-dimensional (2D) fast spin-echo (SE), and three-dimensional (3D) fast SE sequences; and to clarify the usefulness and limitations of MRCP in diagnosing pancreatic abnormalities. MATERIALS AND METHODS: Half-Fourier RARE MRCP images with varying parameters were compared by using a phantom. Duct conspicuity and contrast-to-noise ratios (C/Ns) were compared for the four MRCP techniques in a phantom and healthy volunteers. The optimal MRCP technique was used to study healthy volunteers and clinical cases. Receiver operating characteristic (ROC) curves were created for data analysis. RESULTS: A 5-mm-thick section without intersection gap was appropriate for half-Fourier RARE MRCP. Only half-Fourier RARE MRCP could depict a 1-mm duct. C/N was the highest with half-Fourier RARE, followed by 3D fast SE, 2D fast SE, and SSFP sequences. ROC curve analysis revealed no interobserver differences, and the area under the curve for detection of strictures of the main pancreatic duct was as high as 0.89. CONCLUSION: Half-Fourier RARE MRCP has the highest contrast and spatial resolution among the four techniques studied and may play an important role in diagnosing pancreatic abnormalities.

Adult↗

PubMed1998

Transient low T cell response to streptococcal pyrogenic exotoxin-C in patients with Kawasaki disease.

Superantigens (SAs) are known to induce transient anergy followed by T cell activation. Recent reports have suggested that SAs are involved in the pathogenesis of Kawasaki disease (KD). In the present study, we investigated the peripheral T cell response to SAs by measuring proliferation and IL-2 production to determine whether the T cell anergy is induced by SAs in patients with KD. T cells were obtained from 45 Japanese patients with KD in different stages of the disease and were stimulated by streptococcal pyrogenic exotoxin (SPE)-A, SPE-C, and toxic shock syndrome toxin-1 (TSST-1). T cells from patients with KD in the acute or convalescent stage up to 2 mo showed significantly lower proliferation and IL-2 production than did T cells from healthy control subjects stimulated by SPE-C, but not SPE-A or TSST-1. The T cell response to SPE-C normalized within 1 y. The low T cell response to SPE-C in the acute stage correlated with a peak platelet count and the C-reactive protein-positive period. These findings suggest that the transient low T cell response to SPE-C in patients with KD may have been related to SA-induced anergy or disappearance of SPE-C-responding cells from the circulation. The present results suggested that SPE-C may be involved in the pathogenesis of KD.

Acute Disease↗

PubMed1998

Increased serum levels of vascular endothelial growth factor in Kawasaki disease.

Vascular endothelial growth factor (VEGF) is an angiogenic mitogen that specifically targets vascular endothelial cells. The objective of this study was to evaluate the role of VEGF in Kawasaki disease (KD), the most common cause of systemic vasculitis in childhood. Serum VEGF levels were measured by ELISA in 22 patients with KD, 22 febrile children with infection, and 19 healthy children. Samples from KD patients were divided into three groups: acute stage (n = 20), subacute stage (n = 13), and convalescent stage (n = 15). The results showed that KD patients in the acute and subacute stages had significantly higher levels of VEGF than did patients with infectious diseases and the healthy control subjects. When compared with the VEGF levels of patients with and without coronary artery lesions (CAL), significantly higher levels of VEGF were observed in the subacute stage in patients with CAL and in patients without CAL in the acute stage. Serial examination revealed that the serum VEGF levels in KD patients with CAL increased from a relatively low level in the acute stage to an extremely high level in the subacute stage. In contrast, patients without CAL were found to have extremely high levels of VEGF only in the acute stage of KD. In KD patients, the serum VEGF levels did not correlate with the inflammatory markers and clinical symptoms. Our results raise the possibility that VEGF is involved in the pathogenesis of KD, especially in the development of CAL. Further study is needed to clarify the biologic effect of VEGF on coronary arteries in KD.

Acute Disease↗

PubMed1998

Cell heterogeneity upon myogenic differentiation: down-regulation of MyoD and Myf-5 generates 'reserve cells'.

When a proliferating myoblast culture is induced to differentiate by deprivation of serum in the medium, a significant proportion of cells escape from terminal differentiation, while the rest of the cells differentiate. Using C2C12 mouse myoblast cells, this heterogeneity observed upon differentiation was investigated with an emphasis on the myogenic regulatory factors. The differentiating part of the cell population followed a series of well-described events, including expression of myogenin, p21(WAF1), and contractile proteins, permanent withdrawal from the cell cycle and cell fusion, whereas the rest of the cells did not initiate any of these events. Interestingly, the latter cells showed an undetectable or greatly reduced level of MyoD and Myf-5 expression, which had been originally expressed in the undifferentiated proliferating myoblasts. When these undifferentiated cells were isolated and returned to the growth conditions, they progressed through the cell cycle and regained MyoD expression. These cells demonstrated identical features with the original culture on the deprivation of serum. They produced both MyoD-positive differentiating and MyoD-negative undifferentiated populations once again. Thus the undifferentiated cells in the serum-deprived culture were designated 'reserve cells'. Upon serum deprivation, MyoD expression rapidly decreased as a result of down-regulation in approximately 50% of the cells. After this heterogenization, MyoD positive cells expressed myogenin, which is the earliest known event of terminal differentiation and marks irreversible commitment to this, while MyoD-negative cells did not differentiate and became the reserve cells. We also demonstrated that ectopic expression of MyoD converted the reserve cells to differentiating cells, indicating that down-regulation of MyoD is a causal event in the formation of reserve cells.

Animals↗

PubMed1998

Autoimmune pancreatitis: CT and MR characteristics.

OBJECTIVE: Our goal was to elucidate the CT and MR imaging characteristics in patients with autoimmune pancreatitis, which is a reversible chronic pancreatitis with an autoimmune cause. CONCLUSION: On CT and MR imaging, a capsulelike rim, which is thought to correspond to an inflammatory process involving peripancreatic tissues, appears to be a characteristic finding of autoimmune pancreatitis. Also, diffuse pancreatic enlargement along with hypointensity on T1-weighted MR images and delayed enhancement on dynamic CT and MR studies are other features of this disorder.

Aged↗

PubMed1998

Value of MR cholangiopancreatography in evaluating choledochal cysts.

OBJECTIVE: The aim of this retrospective study was to clarify whether MR cholangiopancreatography (MRCP) is a suitable replacement for ERCP in evaluation of the choledochal cyst. MATERIALS AND METHODS: Sixteen patients (six adult and 10 pediatric) with choledochal cysts underwent MRCP using a half-Fourier acquisition single-shot turbo spin-echo sequence. Extent of the cyst, defects within the biliary tree, and presence or absence of the anomalous junction of the pancreaticobiliary duct were evaluated. Findings were compared with those of ERCP. RESULTS: MRCP better defined the proximal biliary tree than did ERCP in two patients. Defects within the biliary tree were diagnosed correctly on MRCP in eight patients; however, two defects within the distal common bile duct were missed in pediatric patients. The presence of the anomalous junction of the pancreaticobiliary duct was revealed accurately by MRCP in all adult patients but was revealed accurately in only four of the 10 pediatric patients. CONCLUSION: MRCP appears to offer diagnostic information that is equivalent to that of ERCP for assessment of choledochal cysts in adults. In pediatric patients, MRCP should not replace ERCP; however, MRCP can play an important role as a noninvasive examination and should be considered a first-choice imaging technique for evaluation of choledochal cysts.

Adult↗

PubMed1998

Maturation site of dengue type 2 virus in cultured mosquito C6/36 cells and Vero cells.

The maturation of dengue virus (type 2, New Guinea B strain; abbreviated Den-2) in cultured mosquito C3/36 cells and Vero cells was studied by immunoelectron microscopy for the first 7 days after cells were infected, assays of the virus were done by the peroxidase-antiperoxidase method. Virus titers in both kinds of cells were highest on day 6. These cells were then observed with an electron microscope. Den-2 was round and measured about 50 nm in diameter. The virus matured mainly at the membranes of cytoplasmic vacuoles and vesicles, but a few budding viral particles were seen in the cell surface membrane. Immunogold labelling with rabbit antiserum against the E protein of Japanese encephalitis virus was used to locate specific antigens of the Den-2 envelope protein. The results showed that the E protein was in vacuoles, vesicles, and endoplasmic reticulum of the cells. In this study there were no differences between C6/36 cells and Vero cells infected with Den-2.

Animals↗

PubMed1998

The antibacterial activity of plaunotol against Staphylococcus aureus isolated from the skin of patients with atopic dermatitis.

Plaunotol was tested for possible antibacterial activity against twenty strains of methicillin-resistant Staphylococcus aureus (MRSA) and fourteen strains of methicillin-sensitive S. aureus (MSSA) which had been isolated from the skin of patients with atopic dermatitis under growth-promoting conditions. Plaunotol was effective against all strains tested. The dose of plaunotol for 50% inhibition of growth (ID50) ranged from 2.5 to 16 micrograms/ml for strains of MRSA and from 2.5 to 7.0 micrograms/ml for those of MSSA. These results suggest that plaunotol may be useful in the prevention of infection by MRSA and in skin care for patients with atopic dermatitis.

Anti-Bacterial Agents↗

PubMed1998

PET evaluation of cerebral hemodynamics in occlusive cerebrovascular disease pre- and postsurgery.

UNLABELLED: We studied cerebral blood flow (CBF), oxygen extraction fraction (OEF), transit time (TT) and hemodynamic reserve capacity using acetazolamide (ACZ) in both the pre- and postoperative states, and evaluated the effect of surgery on the cerebral hemodynamics. METHODS: Twelve patients with a unilateral occlusive cerebral artery were studied. Among them, seven patients had extracranial-intracranial (EC-IC) bypass surgery, while the remaining five patients had carotid endarterectomies. The CBF was measured using the (15)O-water bolus injection method in a resting state, 5 and 20 min after intravenous ACZ (1 g), while the OEF and TT were measured by the (15)O steady state method. The values of these parameters were obtained by regions of interest set over the cerebral hemisphere on both sides, and which then were compared between the pre- and postoperative states using the paired Student's t-test. RESULTS: The t values were 1.36 (CBF at rest), 2.97 (CBF at 5 min after intravenous ACZ), 1.40 (CBF at 20 min after intravenous ACZ), 2.00 (OEF) and -0.86 (TT) on the surgical side, and -0.16, 0.21, 0.22, -0.47 and 0.61 on the nonsurgical side, respectively. The t values of the ACZ response (% increase in CBF) were 3.07 (5 min after intravenous ACZ) and 0.72 (20 min) on the surgical side, and 1.03 and 0.90 on the nonsurgical side, respectively. A significant change was observed only in the CBF studies 5 min after intravenous ACZ. CONCLUSION: PET can demonstrate significant cerebral hemodynamic change after surgery, especially in CBF measurement 5 min after intravenous ACZ, and may therefore be useful for evaluating cerebral hemodynamics pre- and postsurgery.

Acetazolamide↗

PubMed1998

Carbon-11-methionine PET in focal cortical dysplasia: a comparison with fluorine-18-FDG PET and technetium-99m-ECD SPECT.

UNLABELLED: Focal cortical dysplasia is one of the known neuronal migration disorders and has recently been recognized as a cause of intractable epilepsy. In this study, we assessed the 11C-methionine (MET) uptake in focal cortical dysplasia by PET, and then compared the results with that of 18F-fluoro-2-deoxy-D-glucose (FDG) PET and 99mTc-ethyl cysteinate dimer (ECD) SPECT. METHODS: Four patients (3 men, 1 woman; age range 16-68 yr) were examined by PET and SPECT for a presurgical examination of medically intractable seizures. In all 4 patients, 11C-MET PET was performed for 15 min, started 15 min after the administration of 511-662 MBq MET. In 3 of 4 patients, FDG PET was performed for 15 min, and started 20 min after the administration of 185-370 MBq FDG. In all 4 patients, the cerebral blood flow was also evaluated by 99mTc-ECD SPECT for 15 min after the administration of 600 MBq ECD. RESULTS: In MET PET, all 4 lesions were visually recognized to have high MET uptake areas. The MET uptake of the lesions was 1.44 +/- 0.30 for the standardized uptake value (SUV) (ranging from 0.99-1.61). In FDG PET, 2 lesions were demonstrated to have low uptake areas (3.82 in SUV) while 1 had an ictal high uptake (4.74 in SUV). In ECD SPECT, 1 lesion demonstrated hypoperfusion and 1 ictal hyperperfusion while 2 showed no abnormalities. All 4 patients underwent a cortical resection and the microscopic examinations were consistent with those of focal cortical dysplasia but no evidence of a tumor was found. CONCLUSION: MET PET is useful for identifying focal cortical dysplasia as a high uptake area.

Adolescent↗