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Biomedical subjects

K Masuda

Publications and source records attributed to K Masuda.

At least 181 records · Page 10Linked to original sources
PubMed1999

Vascular changes in hepatocellular carcinoma: correlation of radiologic and pathologic findings.

OBJECTIVE: Our objective was to analyze the hemodynamic properties and vascular supply changes in the carcinogenesis of hepatocellular carcinoma. MATERIALS AND METHODS: Ten nodules (nine patients) (one early, three early-advanced, and six advanced cases of hepatocellular carcinoma) less than 3 cm in diameter were selected from 45 patients (50 nodules) who underwent CT arteriography and CT during arterial portography. These images were correlated with histopathologic findings. Ratios of all microscopically counted (normal hepatic and abnormal) arteries, normal hepatic arteries, and portal veins in each nodule to those in the surrounding liver were calculated. RESULTS: Early hepatocellular carcinoma (one early case and early areas in three early-advanced cases) had low attenuation on CT arteriography and isoattenuation on CT during arterial portography. Advanced hepatocellular carcinoma (six advanced cases and advanced areas in three early-advanced cases) had high attenuation on CT arteriography and low attenuation on CT during arterial portography. In early hepatocellular carcinoma, the ratios of all arteries, normal hepatic arteries, and portal veins were 1.21 +/- 0.07, 0.60 +/- 0.07, and 0.73 +/- 0.06, respectively. In advanced hepatocellular carcinoma, the ratios were 2.66 +/- 0.26, 0.08 +/- 0.04, and 0.07 +/- 0.03, respectively. CONCLUSION: In early hepatocellular carcinoma, the combination of normal hepatic artery degeneration and preserved portal veins results in low attenuation on CT arteriography and isoattenuation on CT during arterial portography. In advanced hepatocellular carcinoma, the combination of neoplastic (abnormal) arterial development by angiogenesis and obliteration of portal veins results in high attenuation on CT arteriography and low attenuation on CT during arterial portography. These findings are a characteristic difference between early and advanced hepatocellular carcinoma.

Aged↗
PubMed1999

New classification of small pulmonary nodules by margin characteristics on high-resolution CT.

PURPOSE: To analyze margin characteristics of pulmonary nodules on high-resolution CT (HRCT) in order to improve imaging diagnoses. MATERIAL AND METHODS: HRCT images of 193 pulmonary nodules of less than 30 mm maximum diameter (113 primary cancers, 15 metastatic cancers, 55 inflammatory nodules, and 10 benign tumors) were reviewed and classified as to 6 types of margins: round, lobulated, densely spiculated, ragged, tentacle or polygonal and halo. The relationships of these imaging types to the diagnoses, the underlying pathological features, mainly those of tumor growth patterns in 93 neoplasms, and the pathological characteristics of 14 inflammatory nodules were investigated. RESULTS: Eighty-two percent of the lobulated, 97% of the densely spiculated, 93% of the ragged and 100% of the halo nodules were malignant. Eighty percent of the tentacle or polygonal nodules were inflammatory and 66% of the round ones were benign. The 6 types differed statistically as to the nature of the benignity/malignancy (p<0.001). Pathologically, in case of neoplasms, most of the 6 types had a relationship to a particular tumor growth pattern. CONCLUSION: This HRCT classification method is useful for determining the nature of small pulmonary nodules and reflects the underlying pathological characteristics.

Adenocarcinoma↗
PubMed1999

[Quantification of cerebral blood flow using 123I-IMP SPECT--a new method of estimating the input function from brain dynamic data].

In order to avoid continuous arterial blood sampling, we estimated input function by the method in that the whole brain time activity curves were fitted by two-term exponential function and differentiated analytically after the injection of N-isopropyl-p-[123I]iodoamphetamine (123I-IMP). This method was applied to 4 patients with cerebral infarction and 2 patients with brain tumor. Values of regional cerebral blood flow (rCBF) were calculated from the input function calibrated by one-point arterial sampling at 5 minutes after the injection using microsphere method, and then were compared with those obtained from the table-lookup method. In this study, we used the individual input function for the table-lookup method instead of the standard input function. The overall accuracy errors between two-term exponential functions and the whole brain time-activity curves were about 1%. The values of rCBF calculated by this method were well correlated with those by the table-lookup method (r = 0.901, p < 0.001). Optimal calibration time for this method was between 3-minute and 10-minute after 123I-IMP injection and the deviation of the rCBF values obtained by this method from those obtained by the table-lookup method in which the input function was calibrated at 5 minutes remained within 10%. This method is a less invasive and convenient alternative to the conventional methods which require continuous arterial blood sampling.

Adult↗
PubMed1999

[Invasive amebiasis at an institution for the mentally retarded in Hyogo Prefecture].

An outbreak of amebiasis caused by Entamoeba histolytica occurred at an institution for mentally retarded persons in Hyogo Prefecture. Twelve out of a total of 49 admitted persons exhibited E. histolytica cysts in their stool, and 13 including persons in whom no cysts had been detected showed positive serological reactions for E. histolytica infection. However, neither the cyst nor the antibody against the organism was detected in the staff members of the institution. Indirect fluorescence antibody test and sandwich enzyme-linked immunosorbent assay with a monoclonal antibody specific for pathogenic strains of E. histolytica revealed that all trophozoite strains grown from cysts in stool samples from five patients were pathogenic. Epidemiological analysis strongly suggested that a patient in the institution had been infected with an organism from a patient outside the institution, and that infection may have spread among the admitted persons due to abnormal behavior. Administration of metronidazole resulted in effective elimination of the cysts from the stool of the cyst-carriers.

Adult↗
PubMed1999

Differential diagnosis of thymic tumors using a combination of 11C-methionine PET and FDG PET.

UNLABELLED: We assessed the usefulness of PET studies in making a differential diagnosis of thymic tumors by using 11C-methionine (MET) and 18F-fluorodeoxyglucose (FDG). METHODS: We examined 31 patients with thymic tumors, including 14 patients with thymic cancer, 9 with invasive thymoma, 5 with noninvasive thymoma and 3 with thymic cysts. The histological diagnosis was confirmed by either surgery or biopsy. MET PET and FDG PET were performed in 28 and 29 patients, respectively. Both the MET and FDG uptakes were evaluated by the standardized uptake value (SUV). RESULTS: MET uptake was not substantially different among thymic cancer (4.8 +/- 1.4), invasive thymoma (4.3 +/-1.1) and noninvasive thymoma (4.5 +/- 1.2), bat MET uptake in thymic cysts (0.9 +/- 0.1) was lower than that in the other three tumors (P < 0.01). The FDG uptake in thymic cancer (7.2 +/- 2.9) was higher than that in invasive thymoma (3.8 -/+ 1.3), noninvasive thymoma (3.0 +/- 1.0) and thymic cysts (0.9) (P < 0.01). MET uptake in thymic tumors correlated with the FDG uptake (r = 0.65), whereas MET uptake in thymic cancer was lower than FDG uptake (FDG/MET ratio = 1.52 +/- 0.52) but was higher than FDG uptake in both invasive and noninvasive thymoma (FDG/ MET ratio = 0.86 +/- 0.33). To differentiate thymic cancer from thymoma, a receiver operating characteristic (ROC) analysis was performed. The area under the curve of FDG PET was 0.90, whereas the FDG/MET ratio was 0.87. CONCLUSION: The MET PET, FDG PET and the FDG/MET ratios were unable to differentiate benign thymic tumors from malignant ones, although FDG PET was considered to be useful in the differential diagnosis between thymic cancer and thymoma. Although the difference in the uptake ratio between FDG and MET suggests a different origin of the tumors, the FDG/MET ratio is not considered to be useful as a complementary method for the differential diagnosis of thymic tumors.

Adult↗
PubMed1999

Prediction of the chemosensitivity of lung cancer by 99mTc-hexakis-2-methoxyisobutyl isonitrile SPECT.

UNLABELLED: 99mTc-hexakis-2-methoxyisobutyl isonitrile (MIBI) has been reported to accumulate in various tumors and to be a transport substrate for P-glycoprotein (Pgp). The aim of this study was to evaluate the usefulness of 99mTc-MIBI SPECT for in vivo assessment of lung cancer chemosensitivity. Also examined was the relationship between 99mTc-MIBI uptake and Pgp expression. METHODS: Ten lung cancer patients who had undergone surgery were examined. Before surgery, 99mTc-MIBI SPECT was performed 15 and 120 min after injection, and the early uptake (L/Ne), delayed uptake (L/Nd) and washout rate (L/Nwr) of 99mTc-MIBI were calculated by the count ratio of lesion to contralateral normal lung tissue. The results were then compared with chemosensitivity determined by the succinate dehydrogenase inhibition test using six antitumor drugs (doxorubicin, mitomycin C [MMC], vindesine, etoposide [VP-16], cyclophosphamide and cisplatin). Pgp expression was determined by immunohistochemical staining. RESULTS: Sensitivity to MMC correlated significantly with L/Ne (P < 0.01) and L/Nwr (P < 0.05). Sensitivity to VP-16 correlated weakly and insignificantly with L/Nwr. L/Nd showed no correlation with sensitivity to any drug. Neither L/Ne, L/Nd nor L/Nwr was significantly different between the Pgp-positive group (n = 2) and the Pgp-negative group (n = 8). CONCLUSION: The results suggest that 99mTc-MIBI SPECT, a noninvasive in vivo examination, can predict the chemosensitivity of lung cancer to MMC and VP-16 independently of Pgp expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

The GroEL-like protein from Campylobacter rectus: immunological characterization and interleukin-6 and -8 induction in human gingival fibroblast.

The native GroEL-like protein was purified from Campylobacter rectus, a putative periodontal pathogen, by affinity chromatography on ATP-agarose followed by high performance liquid chromatography on Superose 6. The purified 64-kDa protein (denatured form of GroEL-like protein) was immunoreactive by SDS-PAGE and Western immunoblotting with the monoclonal antibody directed against heat shock protein 60 of human origin. The native GroEL-like protein stimulated both interleukin-6 (IL-6) and IL-8 secretion by a confluent monolayer of human gingival fibroblast in their culture supernatant. During the 22-h incubation, the amounts of IL-6 and IL-8 were increased by 5.4- and 3.5-fold, respectively. These data suggested that the GroEL-like protein might be considered to be a virulence factor of C. rectus in periodontal disease.

Amino Acid Sequence↗
PubMed1998

A new culture system to study the metabolism of the intervertebral disc in vitro.

STUDY DESIGN: This study determined whether entrapment of a rabbit intervertebral disc in alginate gel helped to promote the retention of normal metabolic activities by the nucleus pulposus and anulus fibrosus in tissue culture. OBJECTIVES: To establish an in vitro culture system to study the metabolism of the intervertebral disc as a whole integral organ. SUMMARY OF BACKGROUND DATA: In vitro studies of the metabolism of intervertebral discs have been scarce because of the difficulties involved in maintaining the integrity of the tissues, especially that of the nucleus pulposus, in culture medium. METHODS: Rabbit intervertebral discs were embedded in alginate gel and maintained in culture for as long as 1 month. At weekly intervals, experiments were performed to measure the rate of proteoglycan synthesis and to characterize proteoglycans newly synthesized by cells in the anulus fibrosus and nucleus pulposus. In addition, at these same time intervals, the contents of sulfated proteoglycans, antigenic keratan sulfate, hyaluronan, and collagen in these two intervertebral disc tissues were measured to evaluate tissue integrity. Intervertebral discs cultured in medium alone were used as controls and analyzed in parallel. RESULTS: The anulus fibrosus and nucleus pulposus of intervertebral discs cultured in alginate gel sustained a higher rate of proteoglycan synthesis and maintained a higher content of extracellular matrix components than the respective controls at all times. CONCLUSIONS: This new alginate tissue culture system should prove useful for studying the metabolism of whole intervertebral discs.

Alginates↗
PubMed1998

Enhancement of the Nipple-Areolar-Complex on Contrast-Enhanced MR Imaging of the Breast.

OBJECTIVE: To evaluate patterns of enhancement in the nipple-areolar-complex (NAC) on contrast-enhanced MRI. METHODS: We reviewed the MR images of 37 patients in which enhancement of the NAC was demonstrated on gadolinium-enhanced dynamic fast radiofrequency spoiled gradient recalled echo (fast-SPGR) images. Time intensity profiles derived from signal intensity values were constructed, and findings correlated with histological results. RESULTS: Three types of curve were observed. In the first type seen in adenoma of the nipple, rapid initial increase in signal intensity with an early peak (1 min) occurred followed by gradual washout. In the second type seen in direct invasion from carcinoma, subareolar intracystic papilloma, or Paget's disease, rapid initial increase in signal intensity followed by a more gradual increase or plateau was seen. In the third type seen in carcinoma without nipple invasion, fibrocystic disease and fibroadenoma, a gradual increase in signal intensity was observed throughout the examination period. CONCLUSION: Early and prominent enhancement of the NAC on contrast-enhanced MRImay indicate the presence of a primary lesion in the NAC or secondary involvement by a primary tumor elsewhere in the breast.

Journal Article↗
PubMed1998

Affinity maturation in Lyn kinase-deficient mice with defective germinal center formation.

Lyn kinase-deficient (lyn-/-) mice show several abnormalities such as reduced numbers of circulating B cells, hyper-IgM, and low proliferative responses induced by CD40 ligand. Lyn-/- mice also develop splenomegaly, produce autoreactive Abs with age, and finally develop glomerulonephritis. Another abnormality observed in lyn-/- mice is that their disability to form germinal centers (GCs). It has been considered that GCs play an important role in affinity maturation and differentiation to B cell memory upon immunization with thymus-dependent Ag. Since Lyn kinase has been thought to be downstream of the signals from the B cell Ag receptor as well as CD40, we studied whether or not lyn-/- mice could exhibit normal Ag-specific class switching and affinity maturation following somatic hypermutation. The mice were immunized with (4-hydroxy-3-nitrophenyl)acetyl-chicken gamma-globulin (NP-CG). Production of NP-specific IgG1 Abs was slightly reduced but clearly detectable. The affinity of Abs produced was comparable to that in wild-type mice. Furthermore, somatic hypermutation occurred in the heavy-chain variable region at the same level as that in wild-type mice. Therefore, we conclude that isotype switching and affinity maturation occur normally in lyn-/- mice without the formation of GCs. The results lead to a speculation that Lyn may not play a role in induction of isotype switching or affinity maturation, despite being downstream of the signals from the B cell Ag receptor complex and CD40, and that GC architecture may not be absolutely essential for affinity maturation.

Amino Acid Sequence↗
PubMed1998

Cloning and characterization of the cDNA for human airway trypsin-like protease.

Previously we isolated a trypsin-like enzyme designated human airway trypsin-like protease from the sputum of patients with chronic airway diseases. This paper describes the cDNA cloning, characterization of the primary protein structure deduced from the cDNA, and gene expression of this enzyme in various human tissues. We obtained an entire 1517-base pair sequence of cDNA with an open reading frame encoding a polypeptide with 418-amino acid residues. The polypeptide consisted of a 232-residue catalytic region and a 186-residue noncatalytic region with a hydrophobic putative transmembrane domain near the NH2 terminus. The polypeptide was suggested to be a type II integral membrane protein in which the COOH-terminal catalytic region is extracellular. Therefore, this protein is thought to be synthesized as a membrane-bound precursor and to mature to a soluble and active protease by limited proteolysis. It showed 29-38% identity in the sequence of the catalytic region with human hepsin, enteropeptidase, acrosin, and mast cell tryptase. The noncatalytic region had little similarity to other known proteins. In Northern blot analysis a transcript of 1.9 kilobases was detectable most prominently in the trachea among 17 human tissues examined.

Amino Acid Sequence↗
PubMed1998

New N-glycans in horseradish peroxidase.

We describe here the structures of several new N-glycan oligosaccharides from horseradish peroxidase (HRP). Glycopeptides from HRP were digested with glycoamidase A (from sweet almond) to release the N-glycans. The oligosaccharides were reductively aminated with 2-aminopyridine, and separated by high-performance liquid chromatography on octadecylsilyl- and amide-silica columns for two-dimensional mapping (Tomiya et al., Anal. Biochem. 171, 73-90, 1988). The N-glycans were also analyzed by electrospray ionization mass spectrometry. Two different lots of HRP showed a considerable difference in their N-glycan composition.

Amidohydrolases↗
PubMed1998

Natural history of colorectal carcinoma: can the tumor volume doubling time be predicted by radiologic findings or immunohistochemical variables?

BACKGROUND AND OBJECTIVES: The factors influencing the growth rate of colorectal carcinoma have not been determined. The aim of this study was to clarify the relationship between the doubling time (DT), morphology, and proliferating cell nuclear antigen, Ki-67 and p53 immunohistochemistry in colorectal carcinoma. METHODS: Thirty-three patients (37 lesions) were studied retrospectively. The DT was calculated and correlated with the initial and final tumor size, morphologic shape, and immunohistochemical results. RESULTS: The DT ranged from 2.4 to 48.0 months (mean: 12.0 months). The mean DT of the early-stage carcinomas was significantly longer than that of the advanced carcinomas. In the latter group, both slowly growing and rapidly growing tumors were observed. The DT showed no correlation with the initial or final size and shape of the tumors on radiographs, or with the immunohistochemical results. CONCLUSIONS: Our data revealed that it is not possible to evaluate the growth rate of colorectal carcinomas based on their morphological shape, cellular proliferative activity, or tumor suppressor gene activity.

Adenocarcinoma↗
PubMed1998

A novel member of the Ig superfamily, RPE7, expressed on the retinal pigment epithelial cell and Müller cell of the bovine retina.

The retinal pigment epithelium of the vertebrate eye plays a major part in the maintenance of ocular function. To identify molecules involved in the exertion of their physiological functions, monoclonal antibodies against bovine retinal pigment epithelial cells were made. Analysis by immunofluoresence and immunoelectron microscopy showed that one of the monoclonal antibodies named anti-RPE7 stained the cell surface of retinal pigment epithelial cells and Müller cells. The anti-RPE7 antibody was revealed to recognize molecules of 45-55 kDa by Western blot analysis. Molecular cloning of the RPE7 cDNA and sequence analysis of the amino acids revealed that protein RPE7 belonged to the Ig superfamily. The high homology of RPE7 with metalloproteinase inducer suggests that the protein RPE7 might play a role in the matrix (interphotoreceptor matrix and basement membranes) remodeling as well as in retinal pigment epithelial cell migration under pathological conditions.

Amino Acid Sequence↗
PubMed1998

Cerebral muscarinic acetylcholinergic receptor measurement in Alzheimer's disease patients on 11C-N-methyl-4-piperidyl benzilate--comparison with cerebral blood flow and cerebral glucose metabolism.

We studied the cerebral muscarinic acetylcholinergic receptor (mACh-R) by means of 11C-N-methyl-4-piperidyl benzilate (11C-NMPB) and positron emission tomography (PET) in Alzheimer's disease (AD) cases, and the findings were compared with the cerebral blood flow (CBF) and the glucose metabolism (CMRGlc) to evaluate the relationship between the mACh-R and the CBF or the CMRGlc. The subjects consisted of 18 patients with AD and 18 age and sex matched normal volunteers. The patients were clinically diagnosed according to the criteria of the NINDS-ADRDA as having "probable AD" and were thus classified into two groups (mild and moderate AD) according to the severity of dementia determined by DSM-III-R. The CBF was measured by 99mTc-HMPAO SPECT, and the CMRGlc was measured by 18FDG PET. The 11C-NMPB uptake was evaluated by the graphical method and the ratio method (ROIs/Cerebellum). A significant mACh-R decrease and more severe CMRGlc decrease in the cortical region was seen in mild and moderate AD. The decrease in the CBF was not as obvious as that in the mACh-R and the CMRGlc. Our study thus suggested that the mACh-R decreased in patients with AD, and that the 18FDG PET was the most sensitive method for detecting the degenerative regions in patients with AD.

Aged↗
PubMed1998

[Resection of a pulmonary infarction presenting as a mass shadow on chest X-ray--case report].

Recently the incidence of pulmonary infarction has increased in Japan. The patient was a 67-year-old male who was examined by a local physician for bloody sputum and a cough. A chest X-ray showed a 5-cm mass shadow in the lower left lung area. Bronchofiberscopy and percutaneous needle biopsy were performed, but they did not permit a definite diagnosis, and since the patient had a 13-year history of penile cancer (squamous cell carcinoma), and metastasis or even primary lung cancer could not be completely ruled out, an open chest biopsy was performed. The postoperative histopathological examination allowed a diagnosis of hemorrhagic pulmonary infarction. We report a case of pulmonary infarction resection that was difficult to diagnose preoperatively.

Aged↗
PubMed1998

A comparative study of thallium-201 SPET, carbon-11 methionine PET and fluorine-18 fluorodeoxyglucose PET for the differentiation of astrocytic tumours.

Thallium-201, carbon-11 methionine (MET) and fluorine-18 fluorodeoxyglucose (FDG) have all been used to assess brain tumours. The aim of this study was to determine which of these tracers are of use for evaluating the histological grade and the extent of astrocytoma. 201Tl single-photon emission tomography (SPET), MET positron emission tomography (PET) and FDG PET were all performed in 23 patients (13 men, 10 women) with newly diagnosed astrocytic tumours [seven with astrocytoma (grade II), ten with anaplastic astrocytoma (grade III) and six with glioblastoma (grade IV)]. The 201Tl uptake of the tumours was evaluated by a lesion-to-normal region count ratio. Both MET and FDG uptake of the tumours was evaluated by a semiquantitative analysis using the standardized uptake value. 201Tl uptake was found to increase in rank order with histological grade and was significantly different among the three groups (grade II: 1.51+/-0.36; grade III: 2.58+/-1.50; grade IV: 7. 65+/-3.84). MET uptake in grade II (1.49+/-0.44) was also significantly lower than that in both grade III (3.29+/-1.44) and grade IV (3.20+/-0.92). FDG uptake was not significantly different among the three groups (grade II: 2.90+/-0.45; grade III: 3.86+/-1. 56; grade IV: 3.57+/-0.83). No significant correlation was observed between 201Tl uptake and either MET uptake or FDG uptake. In most patients, the extent of the increased MET uptake was the largest while that of the increased FDG uptake was the smallest. In patients with positive 201Tl uptake, the extent of the 201Tl uptake was equal to or smaller than that of gadolinium enhancement. For evaluation of histological grade of astrocytic tumours. 201Tl is therefore considered to be useful though the 201Tl uptake in some grade III astrocytomas was not different from that in grade II astrocytomas. MET was found to be highly useful for detecting astrocytomas, for differentiating between benign and malignant astrocytomas, and for evaluating the extent of astrocytomas; however, it was not sufficiently useful permit evaluation of the histological grade. FDG was not found to be useful either for evaluating the histological grade or for differentiating between benign and malignant astrocytomas.

Astrocytoma↗