Search PubMed⌕ Search

Biomedical subjects

J Kawai

Publications and source records attributed to J Kawai.

At least 73 records · Page 4Linked to original sources
PubMed1995

Somatic mosaicism of CAG repeat in dentatorubral-pallidoluysian atrophy (DRPLA).

An unstable expansion of CAG repeat in the coding region of the DRPLA gene on chromosome 12p is the mutation specific for hereditary dentatorubral-pallidoluysian atrophy (DRPLA). We studied the CAG expansion in brain and other tissues from six unrelated DRPLA patients. The CAG repeat lengths showed distinct differences between tissues. The sizes of the CAG expansion in various regions of the brain except the cerebellum were generally larger by several repeats than in other peripheral tissues. Brain samples showed greater variation of the expansion compared with other tissues, but neither the size of the CAG expansion nor the degree of CAG repeat variation parallels the detailed findings of neuropathological involvement. We conclude that somatic instabilities of the CAG repeat cause tissue variability of the CAG repeat size in DRPLA but other region or cell type-specific factors would be involved to explain the selectivity of cell damage in DRPLA.

Adult↗
PubMed1995

Effect of occlusion on human skin.

In order to investigate the effect of occlusion on the skin, the flexor sides of both upper arms were covered with column-shaped with column-shaped closed chambers, 30 mm in outer diameter, 20 mm in inner diameter, and 5 mm in height, which were made of polyethylene foam. The tops of the chambers were sealed by plastic films with various levels of water vapor permeability to control moisture in each chamber. The raised chamber walls prevented direct contact between the skin and the plastic film. After 24 h of application, morphological changes of the skin surface were observed microscopically by the nitrocellulose-replica method. Although no visual alterations were found on all areas of occluded skin, microscopic evaluation showed that simple occlusion by films induced an increase in the number of deepened skin furrows on the skin surface. this increase was associated with lower water vapor permeability of the films, as well as with higher values of both temperature and humidity of the test day. Thus, since conditions which facilitate perspiration from the skin tend to cause skin irritation, prolonged exposure of the skin to sweat by simple occlusion may act as a primary skin irritant.

Adult↗
PubMed1994

Spontaneous complete regression of high grade non-Hodgkin's lymphoma. Morphologic, immunohistochemical, and gene amplification analyses.

BACKGROUND: Spontaneous regression of non-Hodgkin's lymphoma, occasionally reported in low grade groups, is a rare phenomenon in high grade groups. Clonal proliferation has not been confirmed in the majority of reported cases. In this woman, age 58 years, who had been diagnosed as having high grade immunoblastic lymphoma after excision of a single cervical lymph node, the remaining bilateral cervical, inguinal, and axillary adenopathy regressed completely without any cytotoxic treatments 22 days after biopsy. At the time of this writing, the patient has been free of disease for 24 months. METHODS: Clonality of the lymphoproliferation in the case was examined by immunohistochemistry and polymerase chain reaction (PCR) amplification using paraffin embedded biopsy material. Possible implications of Epstein-Barr virus in the pathogenesis of this process was examined also by PCR amplification and in situ hybridization. RESULTS: The proliferating lymphoid cells showed restricted expression of immunoglobulin (Ig) light chain and amplification of clonally rearranged V-D-J regions of Ig heavy chain gene. Epstein-Barr virus did not appear to be involved in the process. CONCLUSION: The present study shows that spontaneous complete regression of clonal lymphoproliferation that is morphologically a high grade lymphoma can occur.

Biopsy↗
PubMed1994

Anticipation in hereditary dentatorubral-pallidoluysian atrophy.

Anticipation refers to the progressively earlier onset and increase in disease severity in successive generations. We studied four families with hereditary dentatorubral-pallidoluysian atrophy (DRPLA), a neurodegenerative disease, and anticipation was present in the mode of inheritance. In subsequent generations DRPLA shows an earlier onset and more severe as well as additional symptoms. Older onset patients suffer from cerebellar ataxia with or without dementia, whereas younger onset patients present as progressive myoclonus epilepsy syndrome, which consists of mental retardation, dementia, and cerebellar ataxia as well as epilepsy and myoclonus. Anticipation with paternal transmission was significantly greater than with maternal transmission.

Adult↗
PubMed1994

A PCR-mediated method for cloning spot DNA on restriction landmark genomic scanning (RLGS) gel.

A PCR-mediated direct cloning for target spot DNA from RLGS gel has been established. The method consists of PCR amplification of adaptor-ligated spot DNA fragments without excluding similar-sized DNA fragments co-localized on RLGS gel, and following selective ligation with the NotI-dT vector. Applying this method, we have successfully cloned several DNA fragments derived from target spots whose intensities change developmentally due to DNA methylation in the telencephalon of C3H/HeN mice. Since only a few micrograms of total DNA is sufficient for our spot cloning, our method may be highly useful when the total DNA sample prepared for cloning is limited.

Animals↗
PubMed1994

A genetic linkage map of the mouse using restriction landmark genomic scanning (RLGS).

We have developed a multiplex method of genome analysis, restriction landmark genomic scanning (RLGS) that has been used to construct genetic maps in mice. Restriction landmarks are end-labeled restriction fragments of genomic DNA that are separated by using high resolution, two-dimensional gel electrophoresis identifying as many as two thousand landmark loci in a single gel. Variation for several hundred of these loci has been identified between laboratory strains and between these strains and Mus spretus. The segregation of more than 1100 RLGS loci has been analyzed in recombinant inbred (RI) strains and in two separate interspecific genetic crosses. Genetic maps have been derived that link 1045 RLGS loci to reference loci on all of the autosomes and the X chromosome of the mouse genome. The RLGS method can be applied to genome analysis in many different organisms to identify genomic loci because it uses end-labeling of restriction landmarks rather than probe hybridization. Different combinations of restriction enzymes yield different sets of RLGS loci providing expanded power for genetic mapping.

Animals↗
PubMed1994

Comparison of DNA methylation patterns among mouse cell lines by restriction landmark genomic scanning.

Restriction landmark genomic scanning (RLGS) is a novel method which enables us to simultaneously visualize a large number of loci as two-dimensional gel spots. By this method, the status of DNA methylation can efficiently be determined by monitoring the appearance or disappearance of spots by using a methylation-sensitive restriction enzyme. In the present study, using RLGS with NotI, we examined, in comparison with a brain RLGS profile, the status of DNA methylation of more than 900 loci among three types of mouse cell lines: the embryonal carcinoma cell line P19, the stable mesenchymal cell line 10T1/2, and our established neuroepithelial (EM) cell lines. We found that the relative numbers of RLGS spots which appeared were less than 3.3% of those surveyed in all cell lines examined. However, 5 to 14% of spots disappeared, the numbers increasing with an increase in the length of the culture period, and many spots were commonly lost in 10T1/2 and in three EM cell lines. Thus, for these cell lines, many more spots disappeared than appeared. However, the numbers of spots disappearing and appearing were well balanced, and the ratio in P19 cells was almost equal to that in liver cells in vivo. These RLGS experimental observations suggested that permanent cell lines such as 10T1/2 are hypermethylated and that our newly established EM cell lines are also becoming heavily methylated at common loci. On the other hand, methylation and demethylation seem to be balanced in P19 cells in a manner similar to that in in vivo liver tissue.

Aneuploidy↗
PubMed1993

Methylation profiles of genomic DNA of mouse developmental brain detected by restriction landmark genomic scanning (RLGS) method.

Restriction landmark genomic scanning using methylation-sensitive endonucleases (RLGS-M) is a newly developed powerful method for systematic detection of DNA methylation. Using this method, we scanned mouse brain genomic DNAs from various developmental stages to detect the transcriptionally active regions. This approach is based on the assumption that CpG methylation, particularly of CpG islands, might be associated with gene transcriptional regulation. Genomic DNAs were prepared from telencephalons of 9.5-, 13.5- and 16.5-day embryos, 1- and 10-day neonates and adults, followed by subjecting them to RLGS-M and comparing their patterns with each other or with that of the adult liver. We used NotI as a methylation-sensitive restriction enzyme and surveyed the methylation states of 2,600 NotI sites, almost of which should correspond to gene loci. Although almost all RLGS spots (98%) were present constantly at every developmental stages, only a few percent of spots reproducibly appeared and disappeared at different developmental stages of the brain (44 spots, 1.7%) and some were tissue-specific (10 spots, 0.7%). These data suggest that DNA methylation associated with gene transcription is a well-programmed event during the central nervous system (CNS) development. Thus, RLGS-M can offer a means for detecting systematically the genes in which the state of DNA methylation changes during development of the higher organism.

Animals↗
PubMed1993

Restriction landmark genomic scanning method and its various applications.

We have developed a new genome scanning method (restriction landmark genomic scanning (RLGS), based on the new concept of using restriction enzyme sites as landmarks. RLGS employs direct end labeling of the genomic DNA digested with a restriction enzyme and two-dimensional electrophoresis with high-resolution. Its advantages are: (i) high-speed scanning ability, allowing simultaneous scanning of thousands of restriction landmarks; (ii) extension of the scanning field using different kinds of landmarks in an additional series of electrophoresis; (iii) application to any type of organism because of direct-labeling of restriction enzyme sites and no hybridization procedure; and (iv) reflection of the copy number of the restriction landmark by the spot intensity which enables distinction of haploid and diploid genomic DNAs. The RLGS method has various applications because it can be used to scan for physical genomic DNA states, such as amplification, deletion and methylation. The copy number of the locus of a restriction landmark can be estimated by the spot intensity to find either an amplified or deleted region. The methylation state of genomic DNA can also be discovered by use of a methylation-sensitive restriction enzyme sites as a restriction landmark (restriction landmark genomic scanning for screening methylated sites, RLGS-M). This article introduces the basic principle of RLGS and its applications to the analysis of cancer, mouse mutant DNAs and tissue-specific methylation, showing the usefulness of RLGS for a variety of biological fields.

Animals↗
PubMed1993

Pallidonigroluysian degeneration with iron deposition: a study of three autopsy cases.

In the basal ganglia of three autopsy cases of pallidonigroluysian degeneration, we found marked iron deposition, a finding which has not been mentioned previously in the literature. Besides severe astrogliosis and neuronal loss in the pallidum, Luysian body and nigra, granular deposits of brown pigments were found in the neuropil, microglias, oligodendrocytes and astrocytes in three such the nuclei and the striatum. These brown pigments proved histochemically to be iron. Our histochemical semiquantitative study showed a significantly stronger reaction for iron in the degenerated nuclei in these three cases than in control cases comprising non-degenerative and the other degenerative diseases. Quantitative study with inductively coupled emission spectrometry also demonstrated a markedly higher iron content in the globus pallidus and the striatum in comparison with the control cases. The possibility is discussed that iron deposition plays a role in generating the lesions of pallidonigroluysian degeneration.

Adult↗
PubMed1993

Identification of the reactive sulfhydryl group of 1-aminocyclopropane-1-carboxylate deaminase.

1-Aminocyclopropane-1-carboxylate (ACC) deaminase, a pyridoxal phosphate enzyme that catalyzes cyclopropane ring-opening and deamination of ACC, formed a quinoid intermediate with D-alanine, as shown by the appearance of a 510-nm absorption band. The presence of D-alanine also stimulated the inactivation of ACC deaminase with iodoacetamide. The increase of absorbance at 510 nm and the stimulation of the enzyme inactivation were temperature-dependent with a critical point at around 20 degrees C, indicating a conformational change of the enzyme. To identify a reactive thiol group, this stimulated inactivation and an iodoacetamide derivative, N-(iodoacetamidoethyl)-1-aminonaphthalene-5- sulfonic acid were used. The residue that was modified by the specific reagent was monitored by absorbance at 350 nm through the digestion by lysylendopeptidase and the fractionation of peptides, and it was located at Cys-162 near the midpoint of the whole peptide chain of the ACC deaminase.

Alanine↗
PubMed1992

Evaluation of skin irritancy of sodium lauryl sulphate: a comparative study between the replica method and visual evaluation.

For 20 years, using the replica method, we have evaluated the skin irritancy of about 10,000 commercial products which come into contact with the skin. In this method, test substances are usually applied on the flexor side of the upper arm for 24 h by semi-open patch test. Subsequently, skin replicas are taken and skin irritancy is evaluated microscopically. In the semi-open patch test, test substances are not completely occluded as in the closed patch test. Thus, this method is less invasive than the closed patch test method to the tested subjects. In this study, we investigated the sensitivity of microscopic scoring (MS) of the replica and visual scoring (VS) of the skin. Sodium lauryl sulphate (SLS) at 0.02%, 0.05%, and 0.2% was applied on 20 subjects' upper arms, using closed and semi-open methods. In both the closed patch test and the semi-open patch test, the value of MS correlated with the concentration of SLS, while VS did not show such a clear correlation. In addition, we compared 2 clinical tests for skin irritancy which are commonly performed in Japan: VS of 48 h closed patch test reaction on the subjects' upper backs and MS of 24 h semi-open patch test reaction on the subjects' upper arms (replica method). MS on the upper arms resulted in a constant score, regardless of the location of application, while VS on the upper back produced results which differed widely depending on the location. Thus, the replica method is a useful clinical test for skin irritancy, because it is sensitive, reproducible and non-invasive.

Adolescent↗