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Biomedical subjects

M Tokunaga

Publications and source records attributed to M Tokunaga.

At least 235 records · Page 13Linked to original sources
PubMed1988

Prospective studies on the progress of sicca symptoms in Sjögren's syndrome: subclinical disease develops into the clinical syndrome.

We evaluated prospectively twenty-two subjective sicca features in seventeen patients with Sjögren's syndrome (SS) including six patients with primary SS twice at a six-year interval. In the second evaluation in 1986, the frequency of sicca symptoms was increased for most items, and the mean number of positive symptoms was also increased in the patients compared with the results in 1980. In the first evaluation, three patients lacked any sicca symptoms, and were considered as subclinical SS. Sicca symptoms developed in all three of these patients later. A positive correlation between the number of sicca symptoms and the patients' age was also reconfirmed by the present study. Changes in sicca symptoms between the two evaluations were not correlated with objective findings of exocrine gland involvement determined at the time of diagnosis of SS. The lacrimal or salivary secretion and sialographic findings determined serially were relatively stable during whole observation period, except in some patients. The results indicate that both the symptoms and objective findings of glandular involvement progress very slowly in SS, although patients with subclinical disease eventually develop clinical SS.

Adult↗
PubMed1988

Temperature-induced change of thick filament and location of the functional sites of myosin.

The combination of the small-angle X-ray camera to use the synchrotron radiation (National Lab. of High Energy Physics, Tsukuba) and a sensitive X-ray detecting system (FCR System, Fuji Medical System Inc.) using the imaging plate enabled us to record a small angle X-ray diagram of liver rabbit muscle within few minutes. Live relaxed rabbit muscle kept at 25 degrees C gave clear relaxed pattern, in which myosin layer line can be observed up to 13th order. When it was cooled down to 5 degrees C, it gave the small-angle X-ray pattern which looks like that obtained from contracting frog muscle, whereas cooled muscle produced no tension. The 8th meridional reflection almost vanished. The pattern is different from that obtained from rigor muscle: actin layer line at 72 A spacing can not be observed. The "stiffness" and (1,1) reflection on the equator increased. This indicates that more crossbridges are at the vicinity of the thin filaments without developing tension at low temperature. This might be related to the marked decrease in the rate of the step from M*ADP to M.ADP at low temperature. The position of the ATP binding site, SH1, actin binding site(s) was determined by three-dimensional image reconstruction method. Actin-binding site was determined by comparing the three-dimensional image of actin-tropomyosin-S1 and that of actin-tropomyosin-troponin-Ca. The position of ATP binding site and SH1 was determined by three-dimensional reconstruction of the complexes of actin-tropomyosin and S1 of which the ATP binding site or SH1 was labelled with avidin. It was found that SH1 locates near the actin-binding site at the same side of S1. The distance from head-rod junction to ATP binding site and SH1 was similar. But they locate at the different side of S1 and the distance between two sites is about 5 nm, which is consistent with that obtained by energy transfer method.

Animals↗
PubMed1987

Electron microscopic visualization of the N terminus of the myosin heavy chain using a site-directed antibody.

We determined the spatial location of the N terminus of the heavy chain of rabbit skeletal muscle myosin by electron microscopy, using a site-directed antibody raised against its N-terminal eight residues as an electron microscopic probe. By examining rotary-shadowed images of the heavy meromyosin-antibody complex, we measured distances between the head-rod junction and the attachment site of the antibody bound on the head. The average distance was estimated to be about 12 nm. The result indicates that the N terminus of the heavy chain is located at the middle region of the head.

Amino Acid Sequence↗
PubMed1987

A novel yeast secretion vector utilizing secretion signal of killer toxin encoded on the yeast linear DNA plasmid pGKL1.

The NH2-terminal signal region comprising of approximately 70% length of the prepro-sequence of the pGKL killer precursor protein was found to direct an efficient secretion of the mouse alpha-amylase into the culture medium of Saccharomyces cerevisiae. The alpha-amylase molecule secreted into the culture medium was identified by both immuno-blotting and assay of the enzyme activity. The amount of alpha-amylase secreted via the killer toxin signal was comparable to that directed by the leader sequence of mating factor alpha. The secretion of alpha-amylase using the killer toxin signal was blocked at 37C but not at 25C in sec18-1 host, indicating that alpha-amylase is exported through the normal secretion pathway of S. cerevisiae.

Amino Acid Sequence↗
PubMed1987

Position of the amino terminus of myosin light chain 1 and light chain 2 determined by electron microscopy with monoclonal antibody.

The position of the N terminus of myosin light chain 1 (LC1) and myosin light chain 2 (LC2) of rabbit skeletal muscle was mapped on the myosin head with a monoclonal antibody (SI304), which recognized the amino acid sequence N-trimethylalanyl-prolyl-lysyl-lysyl at the N terminus of LC1 and LC2. The complex of the antibody and myosin was observed by electron microscopy. By selective cleavage of the N terminus of LC1 or LC2 with papain or chymotrypsin, the position of the N terminus of LC1 and LC2 was determined separately. The N terminus of LC2 is located at the head-rod junction. The N terminus of LC1 is 11 nm (+/- 3 nm, standard deviation) from the head-rod junction. This position is near the actin-binding site of the myosin head.

Amino Acid Sequence↗
PubMed1987

Expression and identification of immunity determinants on linear DNA killer plasmids pGKL1 and pGKL2 in Kluyveromyces lactis.

The linear dsDNA plasmids, pGKL1 (8.9 kb) and pGKL2 (13.4 kb) discovered in Kluyveromyces lactis, confer killer and immunity characteristics upon various yeast strains. We have devised an immunity assay and have been able to show the expression of an immunity phenotype in the K. lactis transformants harbouring conventional circular plasmids which contain DNA fragments of pGKL1. Using this expression system, the immunity determinant on pGKL1 was identified as ORF5. In addition, the presence of pGKL2 was proved to be essential for the expression of the immunity phenotype. This is the first demonstration of this new pGKL2 function, as distinct from its known functions for the replication and maintenance of pGKL1 in yeast cells.

DNA Restriction Enzymes↗
PubMed1987

Inter- and intra-pathologist variability in histologic diagnoses of lung cancer.

To estimate variability and reliability in histologic diagnosis (Dx) of lung cancers, lung cancer preparations were divided into eight equal sets and diagnosed independently by an eight-man pathology panel. Majority Dx (Dx affirmed by more than 4 panelists) was regarded as the consensus Dx of each cancer. The consensus rate of each panelist ranged from 78.8% to 96.1% with an average of 89.4%. The consensus rates were not significantly different among the panelists. Relatively high inter-pathologist agreement was observed in squamous cell carcinoma, adenocarcinoma, and small cell carcinoma. However, regarding large cell carcinoma, there was occasional disagreement among the panelists. Forty-seven cancers were reexamined by the same panelists, with no preliminary announcement, 7 months after the first examination to study the intra-pathologist agreement. The rate of the intra-pathologist agreement ranged from 76.6% to 93.3%. Dx of large cell carcinoma was the most intra-changeable. It was concluded that the histologic Dx of large cell carcinoma was the most inter- and intra-changeable, and the most frequent dissenting Dx from it was poorly differentiated squamous cell carcinoma.

Adenocarcinoma↗
PubMed1987

A comparative microphotometric analysis of adult T-cell leukemia/lymphoma (ATLL) in the skin and mycosis fungoides (MF).

In the skin lesions of 16 adult T-cell leukemia/lymphoma (ATLL) and 13 mycosis fungoides (MF), morphological features of cutaneous infiltrates and their cell kinetics were evaluated through microphotometry of nuclear DNA content and nuclear size on Feulgen-stained sections. Lymphomas comprising some giant cells with irregular-shaped nuclei were found only in ATLL and these cells revealed aneuploid high DNA values. In contrast, neoplastic cells with pale cytoplasm in the Giemsa stain were seen more frequently in MF (69.5%) than in ATLL (12.5%). Patterns of the cutaneous infiltration according to skin microenvironments such as perivascular areas, dermal papillae, and periadnexal areas, were similar in the both entities. In the perivascular areas a mixed proliferation of lymphoma cells and non-neoplastic lymphocytes was conspicuous. The lymphoma cells were determined by high DNA values and large nuclear sizes. But the ratio of lymphoma cells to non-neoplastic cells in the infiltrates in the perivascular areas was higher in ATLL than in MF. In the dermal papillae and around the skin appendages, lymphoma cells predominated. Lymphoma cells which formed a plaque or tumor in the dermis contained many actively proliferating cells having higher DNA values and larger nuclear sizes than the lymphoma cells without tumor formation. One case of ATLL intermediate cell type showed, however, few proliferating cells inspite of tumor formation, suggesting a pooling or a long life-span in the skin.

Cell Cycle↗
PubMed1987

Comparative microcytometric analysis of European peripheral T-cell malignant lymphomas (EPTL) and adult T-cell leukemia/lymphomas (ATLL) in Japan.

A simultaneous microcytometric analysis of nuclear DNA content and size was performed in 8 European peripheral T cell lymphomas (EPTL) and 8 adult T-cell leukemia/lymphomas (ATLL), comparing their patterns on the nuclear density scattergram (NDS) of DNA content versus nuclear size. The intermingling lymphocytes with or without irregular-shaped nuclei in EPTL and ATLL were interpreted as stimulated reactive. Medium-sized cell-dominated T-zone lymphomas and ATLL pleomorphic medium-sized cell type showed two distribution patterns in the diploid range. The first was oblique zonal cluster (OZC) with the second high concentration in the middle part of it, suggesting mixed proliferation with stimulated reactive lymphocytes, and the second was the high concentration in the lower region of the NDS with some cells corresponding to the growth fraction. In large cell-dominated T-zone lymphomas and ATLL pleomorphic large cell type, the third decreasing pattern in the cell density from the lower part of the OZC to its upper part was found upto the hypertetraploid range. The wide distribution on DNS and giant cells with aneuploid high DNA content were found only in the pleomorphic large cell type and the pleomorphic medium-sized and large cell type of ATLL. The T-immunoblastic type of EPTL showed the third pattern and the pleomorphic large cell type of EPTL, characteristic in the clear cytoplasm, showed the second pattern.

Cell Nucleus↗
PubMed1987

Incidence of female breast cancer among atomic bomb survivors, Hiroshima and Nagasaki, 1950-1980.

Ascertainment of breast cancer incidence among the cohort of the RERF Life Span Study extended sample identified 574 breast cancers among 564 cases diagnosed during 1950-1980 of which 412 cancers were reviewed microscopically. There were no dose-dependent differences with respect to diagnostic certainty or histological type. As in previous studies, the dose response appeared to be roughly linear and did not differ between the two cities. The most remarkable new finding was the emergence of a radiation-related excess among women under 10 years of age at exposure. The risk of radiogenic breast cancer appears to decrease with increasing age at exposure, whether expressed in relative or absolute terms. These results suggest that exposure of female breast tissue to ionizing radiation at any time during the first four decades of life, even during the premature stage, can cause breast cancer later in life, and that the length of time that tumor promoters such as endogenous hormones operate following exposure has an important influence on the development of radiation-induced breast cancer. An unresolved question is whether breast cancer risk is increased by radiation exposure at ages older than 40.

Age Factors↗
PubMed1986

Regulation of mannitol catabolism in Candida albicans: evidence for cyclic AMP-independent glucose effect.

Candida albicans was examined for a glucose effect and showed typical diauxic growth on a mixture of glucose and mannitol, in which mannitol utilization occurred only after exhaustion of glucose. The activity of NAD-linked mannitol dehydrogenase was very low while glucose was present in the medium, but started to increase after consumption of glucose. This increase in activity was fully prevented by trichodermin, an inhibitor of protein synthesis. The uptake of mannitol was detected in the cells grown on mannitol, but not in those grown on glucose with or without mannitol. Mannitol uptake by mannitol-grown cells was not affected by the presence of glucose (0.2 g l-1). These findings indicate that in C. albicans glucose represses the inducible syntheses of mannitol dehydrogenase and a mannitol transport system, and that the involvement of inducer exclusion in this effect is unlikely. Fructose, and to lesser extents galactose, mannose and sucrose, also exhibited similar effects on mannitol metabolism. No correlation was found between the intracellular cyclic AMP levels and the glucose effect.

Candida albicans↗
PubMed1986

[Diagnostic variations among eight pathologists in the histologic classification of lung cancer].

In order to estimate the magnitude of variations among pathologists in histological diagnoses of lung cancer, eight doctors were asked to independently diagnose 73 preparations of the lung (16 biopsied cancers, 27 resected specimens, 21 autopsied specimens and nine benign autopsied cases). The rates of correct diagnoses by the pathologists ranged from 81.7% to 100%, averaging 91.8%. There was no significant difference between the lowest rate and mean or median of the rates. The variation of the diagnosis tended to be more prominent in large cell carcinoma than in adenocarcinoma or small cell and squamous cell carcinoma. It was suggested that the diagnostic criteria for large cell carcinoma varied to some extent among pathologists.

Adenocarcinoma↗