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T Nagayoshi

Publications and source records attributed to T Nagayoshi.

At least 19 recordsLinked to original sources
PubMed1999

Role of diffusion-weighted echo-planar MRI in distinguishing between brain brain abscess and tumour: a preliminary report.

Our purpose was to evaluate diffusion-weighted (DW) echo-planar MRI in differentiating between brain abscess and tumour. We examined two patients with surgically confirmed pyogenic brain abscess and 18 with metastatic brain tumours or high-grade glioma, using a 1.5 T system. The apparent diffusion coefficient (ADC) of each necrotic or solid contrast-enhancing lesion was measured with two different b values (20 and 1200 s/mm2). All capsule-stage brain abscesses (4 lesions) and zones of cerebritis (2 lesions) were identified on high-b-value DWI as markedly high-signal areas of decreased ADC (range, 0.58-0.70 [(10-3 mm2/s; mean, 0.63)]). All cystic or necrotic portions of brain tumours (14 lesions) were identified on high-b-value DWI as low-signal areas of increased ADC (range, 2.20-3.20 [(10-3 mm2/s; mean, 2.70)]). Solid, contrast-enhancing portions of brain tumours (19 lesions) were identified on high-b-value DWI as high-signal areas of sightly decreased or increased ADC (range, 0.77-1.29 [(10-3 mm2/s; mean, 0.94)]). Our preliminary results indicate that DW echo-planar MRI be used for distinguishing between brain abscess and tumour.

Aged↗
PubMed1998

Diffusion-weighted echo-planar MRI of lacunar infarcts.

We studied 35 patients with lacunar infarcts, using diffusion-weighted echo-planar imaging (DW-EPI) at 1.5 T. The relative apparent diffusion coefficient ratio (ADCR) of each lesion was calculated and lesion conspicuity on DW-EPI was compared to that on images acquired with fast fluid-attenuated inversion recovery and T2-weighted fast spin-echo sequences. Acute small infarcts (within 3 days) were identified with DW-EPI as an area of decreased ADCR (range 0.33-0.87; mean 0.67) and high signal, subacute small infarcts (4-30 days) as a high-signal or isointense areas of decreased or nearly normal ADCR (0.54-0.98; 0.73), and chronic small infarcts (> 30 days) as low- or high-signal areas of nearly normal or increased ADCR (0.97-1.92; 1.32). In three patients, small infarcts of the brain stem in the hyperacute phase (within 6 h) were seen only with DW-EPI. In five patients, fresh small infarcts adjacent to multiple old infarcts could be distinguished only with DW-EPI.

Aged↗
PubMed1995

Concurrent detection of cholecystocolic fistula and hepatic abscess by hepatobiliary scintigraphy.

We report the case of a 58-year-old male with cholecystocolic fistula and hepatic abscess that were not diagnosed by routine radiologic examinations, but concurrently detected by hepatobiliary scintigraphy with 99mTc-PMT, and confirmed at operation. Hepatobiliary scintigraphy is noninvasive and useful in the detection of a biliary enteric fistula and lesions about related organs. Concurrent detection of cholecystocolic fistula and hepatic abscess on hepatobiliary series is of great clinical value in planning surgical intervention.

Biliary Fistula↗
PubMed1995

The value of combined 99mTc-Sn-colloid and 99mTc-RBC scintigraphy in the evaluation of a wandering spleen.

Wandering spleen is the term commonly applied to splenic hypermobility that results from laxity or maldevelopment of its suspensory ligaments. It comes to medical attention usually as an abdominal mass, or when the spleen undergoes torsion. Diagnosis on clinical grounds alone is rarely made, and ultrasonography, CT and MRI findings have no specific characteristics for this condition. 99mTc-labeled colloid taken up by the spleen may provide a specific diagnosis. We report a case of wandering spleen, in which the preoperative diagnosis was made on the basis of sequential liver-spleen scintigraphy with 99mTc-Sn-colloid and blood-pool scintigraphy with 99mTc-RBC. This is a rare case, in which hypermobility was assessed by sequential 99mTc-Sn-colloid scintigraphy, and to our knowledge, is the first case in which 99mTc-RBC scintigraphy provided useful information on splenic blood volume and its location.

Adult↗
PubMed1995

Sequential subtraction scintigraphy with 99mTc-RBC for the early detection of gastrointestinal bleeding.

To improve the early detectability of gastrointestinal (GI) bleeding, we have developed a new subtraction scintigraphic technique using in vivo labeled 99mTc red blood cells (RBC). Use of this new sequential subtraction method every 5 min makes it possible to detect early the bleeding site and calculate the bleeding rate. In phantom experiments, focal activity was detected on subtraction images at pump rates of more than 0.20 ml/min at any urethane thickness, but was negative on conventional scintigrams. The calculated pump rate by the subtraction method correlated well with the actual syringe pump rate (y = 1.07x - 0.02, r = 0.99, p < 0.01) in the case of an 8-cm urethane board as an abdominal wall. Twenty-four of 50 patients with suspected GI bleeding were confirmed to be positive within 24 hr. The subtraction method showed 15 true positive and 2 false positive cases within 60 min. On the other hand, the conventional scintigraphic method showed only 7 true positive and 1 false positive cases. Sensitivity of the subtraction method was 62.5%, which was significantly higher (p < 0.05) than that of the conventional scintigraphic method (29.2%). These results suggest that sequential subtraction scintigraphy with 99mTc-RBC is an effective method for the early detection of GI bleeding and shortening the examination time as compared with conventional scintigraphy.

Adolescent↗
PubMed1995

I-123 MIBG imaging of metastatic carcinoid tumor from the rectum.

I-131 MIBG, a specific radiopharmaceutical agent for scintigraphic imaging and treatment of pheochromocytoma and neuroblastoma may be useful for detection of apudomas. Scintigraphy with I-123 radiolabeled MIBG was performed in a patient with metastatic carcinoid tumor from the rectum. I-123 MIBG scintigraphic findings showed multiple areas of abnormal tumor uptake of hepatic and bone metastases from the rectal carcinoid. Bone scintigraphy demonstrated multiple metastatic lesions. Computed tomography revealed multiple solid tumors of the liver. This report describes accumulation of I-123 MIBG in the liver and bone metastases from the rectal carcinoid. Radioiodine MIBG scintigraphy may be useful for detecting metastatic lesions, for evaluating postoperative recurrence, and also for the treatment of the carcinoid tumor.

3-Iodobenzylguanidine↗
PubMed1995

[Assessment of tumor viability by 201Tl SPECT in VX-2 tumor-bearing rabbits after irradiation: comparison with X-ray CT and pathohistologic findings].

In order to evaluate 201Tl SPECT for the assessment of tumor viability after radiation therapy. Twenty rabbits were implanted with VX-2 tumor in the left femoral muscles and were classified into four groups as follows: normal control group (N), 20 Gy irradiated response group (A), 20 Gy irradiated non-response group (B), and 40 Gy irradiated group (C). Eight days after implantation, 201Tl SPECT and CT studies were performed to assess the changes in 201Tl uptake and tumor volume at 0, 1, 2, 3, and 4 weeks after single irradiation. Histologic specimens were also taken. In group N tumors continued to increase in volume, but 201Tl uptake showed a steady decrease after 2 weeks. In group A tumors continued to increase in volume, but 201Tl uptake showed a transient decrease at 2 weeks, then a steady increase. In group B tumors showed a transient increase in volume at 2 weeks, then a continuous decrease, but 201Tl uptake showed a continuous decrease throughout the study. In group C there was a continuous decrease both in volume and 201Tl uptake with the later more prominent. 201Tl uptake was decreased earlier than tumor volume both in group B and C, at one week that was significant (p < 0.01). 201Tl uptake by tumor reflects the burden of viable tumor on histology; therefore 201Tl SPECT is of great use in assessing the therapeutic effects on tumors.

Animals↗
PubMed1990

Human nidogen gene: identification of multiple RFLP and exclusion as candidate gene in a family with epidermolysis bullosa (EBS2) with evidence for linkage to chromosome 1.

Epidermolysis bullosa (EB) is a group of heritable blistering diseases affecting the dermal-epidermal basement membrane zone. We have recently provided evidence for genetic linkage of the molecular defect in a large family with dominant simplex, generalized (Koebner) type of EB (EBS2) to the long arm of chromosome 1. Because human nidogen gene has been mapped to chromosomal locus 1q43 in the human genome, we examined the possibility that nidogen, an integral component of all basement membranes, would be the candidate gene in this family of EBS2. Restriction fragment-length polymorphism, which was shown with several restriction endonucleases to be present within the nidogen gene, was utilized for linkage analyses. The results using an informative PvuII polymorphism as a marker of allelic inheritance supported exclusion of the EBS2 locus from approximately 10 cM in either side of the nidogen locus, when Lod score of -2.0 was taken as the limit of exclusion. This study demonstrates the feasibility of examining other families with EB for possible linkage to the nidogen locus.

Chromosomes, Human, Pair 1↗
PubMed1989

Human laminin A chain (LAMA) gene: chromosomal mapping to locus 18p11.3.

Laminin, an integral component of basement membranes, consists of three subunit polypeptides, A, B1, and B2 chains. We have recently isolated cDNAs corresponding to human laminin A chain. These cDNAs were utilized for chromosomal in situ hybridizations to establish the genomic location of the laminin A chain gene. Metaphase chromosomes of PHA-stimulated human peripheral blood leukocytes were examined by in situ hybridization with 3H-labeled cDNAs, and the chromosomes were identified by R-banding (fluorochrome-photolysis-Giemsa method). The results indicated that the human laminin A chain is at locus 18p11.3. Since human laminin B1 and B2 chain genes have been previously mapped to chromosomes 7 and 1, respectively, the results indicate that genes encoding human laminin chains reside in separate chromosomes.

Blotting, Southern↗
PubMed1989

Human nidogen: complete amino acid sequence and structural domains deduced from cDNAs, and evidence for polymorphism of the gene.

Nidogen, a multifunctional glycoprotein, is an integral part of all basement membranes. In this study, human nidogen cDNAs were isolated and characterized from human placental and skin fibroblast cDNA libraries by hybridization with a mouse nidogen cDNA probe. Six overlapping clones covering 4.9 kb were characterized. The composite cDNA contained a 3,741-nucleotide open reading frame which coded for a 1,247-amino-acid peptide that included a hydrophobic signal sequence. The deduced amino acid sequence contains seven epidermal growth factor-like cysteine-rich repeats, one possible tyrosine O-sulfation site, and a possible N-glycosylation site. The tripeptide sequence -Arg-Gly-Asp- (RGD), a potential cell attachment site, was also present. Human and mouse nidogen sequences were 84% homologous at the nucleotide level and 85% homologous at the deduced amino acid level. Southern blotting of human leukocyte DNA from 23 individuals indicated that nidogen probably is a single-copy gene and shows multiple restriction fragment length polymorphisms when cleaved with Eco RI, Pvu II, Taq I, and Msp I. In particular, digestions with Pvu II revealed polymorphism in four discrete DNA fragments, which could be discriminated by hybridizations with nidogen subclones. One of the polymorphisms revealed an allelic frequency of 0.52/0.48. Thus, human nidogen gene displays RFLPs which provide analytical tools to establish genetic linkage between the nidogen gene and a clinical phenotype.

Amino Acid Sequence↗
PubMed1989

Human nidogen: cDNA cloning, cellular expression, and mapping of the gene to chromosome Iq43.

A human placental lambda gt11 expression cDNA library was screened for nidogen cDNAs by hybridizations with a heterologous mouse nidogen cDNA. A total of four positive overlapping clones were identified, and the sizes of the inserts were shown to vary from 0.8 to 2.8 kb. Nucleotide sequencing of the human cDNAs revealed that the largest clone, cHPN-16, contained both a 5' open reading frame encoding 582 amino acids and a 3' untranslated region of 1,063 nucleotides. Comparison of human cDNA sequences with mouse nidogen sequences revealed 84% identity on the nucleotide level and 88% identity with the deduced amino acid sequence. The deduced amino acid sequence of the human cDNAs revealed the presence of cysteine-rich epidermal growth factor-like repeats and the sequence Arg-Gly-Asp (RGD), a potential cell binding site, two features previously identified in mouse nidogen. The sequence Asn-Pro-Ser, a consensus sequence for N-linked glycosylation, was also noted. The newly isolated human cDNAs were utilized to analyze the expression of the nidogen gene by cultured human cells. Northern hybridizations revealed a single mRNA transcript of approximately 6.0 kb in human skin fibroblast and in HT 1080 fibrosarcoma cell cultures. However, the human choriocarcinoma cell line JEG-3, which expressed laminin genes, did not contain detectable levels of nidogen mRNAs. Quantitation of the relative nidogen mRNA abundance in HT 1080 fibrosarcoma cells indicated that nidogen mRNA levels were approximately the same as those for the laminin B2 chain. Finally, one of the nidogen cDNAs was used to map the nidogen gene onto locus q43 of chromosome 1.

Amino Acid Sequence↗
PubMed1989

Human laminin: cloning and sequence analysis of cDNAs encoding A, B1 and B2 chains, and expression of the corresponding genes in human skin and cultured cells.

A human placental lambdagt11 expression cDNA library was probed for laminin cDNAs by a combination of immunoscreening using polyclonal anti-human laminin antibody, and plaque hybridizations using a mouse laminin A chain cDNA. A total of 36 recombinant clones were isolated and characterized. Northern blot hybridizations with poly(A)+RNA, isolated from cultured human skin fibroblasts, revealed hybridization either to (a) a single 10 kb transcript consistent with A chain; (b) a single 5.7 kb transcript consistent with B1 chain; or (c) polymorphic 5.6 and 8.2 kb transcripts consistent with B2 chain of human laminin. Nucleotide sequencing of representative cDNA clones (approximately 2.5 kb in size) confirmed that these three groups of cDNAs encoded C-terminal sequences of laminin A, B1 and B2 chains, respectively. Deduced amino acid sequences for both B1 and B2 chains contained epidermal growth factor-like sequences and alpha-helical heptad repeats, as found previously for mouse laminin. Partial laminin A chain cDNA encoded 680 amino acid residues characterized by several internal repeats. This portion of the peptide accounted for a large part of the globular domain (fragment 3), the whole length of a second (T2) and portions of a third (T1) globular domain. The human A chain also contained an Arg-Gly-Asp sequence, a potential cell-binding site, which is not found in the same segment of mouse laminin. The newly isolated cDNAs were also utilized to analyze expression of laminin mRNAs by cultured human cells and tissues. The results demonstrated that the laminin A, B1, and B2 chain genes were expressed in an uncoordinate manner in both cultured cells and tissues, with a particularly low level of the A chain mRNA being present.

Amino Acid Sequence↗
PubMed1988

Genetic analysis of systemic lupus erythematosus: 1. Detection of disease-associated variant proteins by two-dimensional gel electrophoresis.

Various genetic studies indicate that development of systemic lupus erythematosus (SLE) is regulated by the mode of multifactorial inheritance, i.e., by the overall effect of polygenes and environmental factors. To elucidate some variant genes involved in the polygenic system responsible for onset of SLE, we resolved and measured the protein components of lymphocytes and sera from inactive-SLE patients, their relatives, and normal controls, using two-dimensional gel electrophoresis. Intercomparison of polypeptide patterns between patients and controls revealed three major variations, two detected in lymphocytes and one in sera. These variations were present in 66-82% of the patients, in 20-36% of the control group, and in 41-64% of the relatives. In addition, nearly half of SLE patients, but only one of 19 normal controls, possessed all three SLE-associated traits, suggesting that these variant proteins may reflect in part the genetic factors contributing to development of SLE.

Adolescent↗