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Biomedical subjects

M Higurashi

Publications and source records attributed to M Higurashi.

At least 19 recordsLinked to original sources
PubMed1992

The effect of aging on cell-cycle kinetics and X-ray-induced chromosome aberrations in cultured lymphocytes from patients with Down syndrome.

To evaluate the effects of aging on cytogenetic characteristics of lymphocytes from Down syndrome (DS), cell-cycle kinetics after PHA stimulation and chromosome-type aberration frequencies after X-ray exposure were investigated in vitro in the lymphocytes derived from 4 (or 3 for X-ray treatment) age groups of DS patients and age-matched controls. The results clearly showed higher mitotic and proliferation index levels in younger groups compared to older groups at the various culture intervals, whether the lymphocytes were from the DS patients or controls. The age-related changes of the proliferation index were mainly attributed to a delayed response to PHA as age increased. The changes of PHA responses seemed to be particularly marked during adolescence. Nonetheless, no significant differences were observed between the DS patients and age-matched controls for each age group. In all age groups, frequencies of both chromosome-type exchanges and deletions were elevated in the DS patients by about 1.3 times in comparison with the controls. The magnitude of radiosensitivity, however, seemed to decrease slightly in the 40-49-year group. To our knowledge, the present study is the first report in the literature to deal with the effect of aging on the greater radiosensitivity of DS lymphocytes.

Adolescent↗
PubMed1992

Retrocaval ureter with recurrent pyelonephritis.

A case of retrocaval ureter with recurrent pyelonephritis is presented with discussion of these clinical entities. An excretory urogram and retrograde ureterogram disclosed pronounced hydronephrosis as well as a dilated proximal part and reversed J-shaped appearance of the right ureter. The compressed retrocaval portion of the ureter was resected and an end-to-end anastomosis was performed anterior to the vena cava. Due to the progressive kidney damage leading to severe hydronephrosis, a rapid radiological diagnosis should be made to replace the retropositioned ureter.

Adult↗
PubMed1991

The combination of DNA methylation and H1 histone binding inhibits the action of a restriction nuclease on plasmid DNA.

To investigate the potentials of DNA methylation and H1 histone in regulating the action of DNA binding proteins, well ordered complexes were formed by slow salt gradient dialysis of mixtures of H1 histone with either methylated or nonmethylated DNA. The sites methylated in the plasmids were CCGG. Methylation of cytosine in this site protects the DNA against HpaII endonuclease but not against MspI. However, when the methylated DNA was complexed to H1, it was protected against MspI. The protection was only effective for a subset of the MspI restriction sites. The protection of DNA afforded by the combination of H1 binding and DNA methylation did not apply to EcoRI, PstI, or BamHI sites and so did not seem to be due to aggregation of the DNA by H1 histone. Gel retardation assays indicated that the affinity of H1 for methylated DNA was not detectably different from its affinity for nonmethylated DNA. Probably methylated DNA when bound to H1 is in a conformation that is resistant to MspI endonuclease. Such conformational changes induced by DNA methylation and H1 binding might affect the action of other DNA binding proteins, perhaps in chromatin as well as in H1.DNA complexes.

Animals↗
PubMed1991

Heterogeneity of serum and amniotic fluid prolactin in humans.

The molecular heterogeneity of PRL was studied in serum and amniotic fluid using immunoperoxidase electrophoresis. In the amniotic fluid, larger molecular variants (greater than 117 kD), small PRL (20 and 23 kD) and cleaved PRL were present in the nonreduced condition. Newly, three mercaptoethanol (MCE)-resistant forms (76, 64 and 53 kD), and 25- and 23-kD forms appeared after treatment with MCE. Two variants, 64 and 23 kD, did not bind to concanavalin A (Con A), indicating a simple peptide without sugars. Other glycosylated forms, 76, 53 and 25 kD, bound to Con A. In maternal serum, the same components as those in the amniotic fluid were seen, except for a scanty amount of 23 kD and a newly appearing glycosylated variant of 28 kD in the reduced condition. This 23-kD form also appeared with the administration of TRH in women.

Amniotic Fluid↗
PubMed1991

The development of sleep and wakefulness cycle in early infancy and its relationship to feeding habit.

The purpose of this study was to evaluate the relationship between sleep and wakefulness patterns to feeding habits in early infancy. The population consisted of 33 neurologically normal infants studied during their first 4 months of life. The number of 30-min epochs with sleep (sleep epoch) were counted in each 4-hr period in a day and evaluated over time. The effects of feeding on sleep and wakefulness were examined by analyzing the rates of sleep epoch after feeding in each time period. The rates of sleep epochs in each time period showed specific patterns each week. From 2 weeks of age, sleep epochs appeared most frequently in time periods 0:00-4:00 and 4:00-8:00 (p less than 0.01). These periods also had significantly high rates of sleep epochs after feeding by week 2. From week 6 both the number of sleep epochs and the rate of sleep epochs after feeding in time periods from 8:00 to 20:00 tended to decrease. These results suggest that the development of the circadian oscillation is set as a sleep epoch first during the time period of 0:00 to 8:00. In addition, feeding alone seemed to have no role as a time cue in the first 4 months of life.

Circadian Rhythm↗
PubMed1990

Livebirth prevalence and follow-up of malformation syndromes in 27,472 newborns.

The results of a survey of the birth prevalence of congenital anomalies among 27,472 consecutive newborn babies at a large maternity hospital in Tokyo are reported. There were 29 cases with trisomy-21; 5 cases with trisomy-13 syndrome; 5 with trisomy-18 syndrome; 2 with cri-du-chat syndrome; and one each with partial monosomy 4p, partial trisomy 5p, partial trisomy 6p, partial trisomy 9p, partial trisomy 9q, partial monosomy 10p, and partial monosomy 13q. Single cases of the following were observed: the Hallermann-Streiff syndrome, the Treacher-Collins syndrome, achondroplasia, arthrogryposis, the Beckwith-Wiedemann syndrome, the asplenia syndrome, the Klippel-Trenaunay-Weber syndrome, the Marfan syndrome, the Carpenter syndrome, the Goldenhar syndrome, and the Pierre Robin syndrome. The results of follow-ups to determine the life-prognosis of each patient with an autosomal aberration are reported.

Chromosome Aberrations↗
PubMed1989

Ullrich-Turner syndrome and anorexia nervosa.

We report on a 6-year-old girl with Ullrich-Turner syndrome and anorexia nervosa. The diagnosis was made at 6 years and she became anorectic at 14 years. She had been treated with low doses of estrogen just before the onset of anorexia. In spite of remarkable decrease in food intake, her body weight was in the normal range compared to standard weight. Rohrer indices were also normal, probably due to abnormal habitus in individuals with the syndrome. The pathogenetic relationship between this disorder and the hormone treatment in the onset of anorexia nervosa is discussed.

Anorexia Nervosa↗
PubMed1989

Mitomycin-C-induced sister-chromatid exchanges and cell-cycle kinetics in lymphocytes from patients with Klinefelter syndrome.

The chromosomal sensitivity to mitomycin-C (MMC) and cell-cycle kinetics in cells from patients with Klinefelter syndrome, a sex chromosomal disorder giving a high risk of malignant tumor, were studied by techniques of sister-chromatid exchanges (SCEs). The frequencies of MMC-induced SCEs increased in proportion to the increase in MMC concentration in both patient and normal control cells. At low levels of MMC there were no significant differences in SCE frequencies between the patient and normal control cells, but at MMC concentrations of 3 X 10(-8) M (p less than 0.05) and 1 X 10(-7) M (p less than 0.01), significant increases in the frequency of MMC-induced SCEs were observed in cells from patients compared to cells from normal controls. Although the analysis of cell-cycle kinetics both after various culture times and after treatment with MMC revealed that there were no significant differences between the patient and normal control cells, patients with Klinefelter syndrome showed a tendency to cell-cycle delays after treatment with MMC in comparison with normal controls.

Cell Cycle↗
PubMed1989

Effects of high-rise living on physical and mental development of children.

Effects of high-rise living on infants' development were investigated in 1987-1988 in a high-rise residential area in Tokyo, using questionnaires on the daily behaviors of a total of 1,045 infants, completed by mothers and kindergarten teachers. Infants of high-rise living showed a delayed independence in fundamental daily customs compared with those of low-rise living. This could be ascribed to an over-attachment of mothers of high-rise living with their infants resulting from a reduced number of outings.

Activities of Daily Living↗
PubMed1979

Chromosome survey of newborn infants in Tokyo: follow-up study for XYY.

In order to ascertain the frequency of chromosome aberrations among newborn infants in Japan, a chromosome survey of a large number of newborn infants is in progress. A series of 10,270 consecutive newborn babies, 5,341 male and 4,929 female, have been screened for clinical manifestations of autosomal aberrations and for sex-chromatin and sex-chromosome aberrations. Chromosome studies were carried out on 185 infants with suspected chromosome aberrations. Of these, 23 had abnormal karyotypes, including 2 males with a 47,XXY complement, 1 female with 45,X complement, 3 males with a 47,XYY complement, 2 with trisomy 13 syndrome, 3 with trisomy 18 (including one mosaicism), 10 with Down syndrome (including 1 mosaicism), 1 with B5p partial trisomy, and 1 with Y-D translocation. Developmental studies of four XYY children and one 45,X girl are in progress.

Chromosome Aberrations↗
PubMed1978

Incidence of 47,XYY karyotype in a consecutive series of newborn males in Tokyo.

A series of 3545 newborn males, born consecutively at a maternity hospital in the western suburbs of Tokyo and with no detectable physical abnormalities, were studied for fluorescent Y-chromatin. Buccal cell smears from each infant were screened. Cases with ambiguous results were subjected to a second test by blood smears, which were found to be more reliable. After the second test, chromosomal analysis was carried out in five infants: three had a 47,XYY karyotype; one, the karyotype 46,XY-D,t(D:Y) (Iijima et al., in preparation); and one, a normal male karyotype. The XYY karyotype occurred in 0.11% of newborn males in this series.

Cheek↗
PubMed1978

The transition in frequency of Y chromatin in males during the neonatal period.

The frequency of Y chromatin, visualized as fluorescent bodies in cell nuclei from lymphocytes in blood smears, was significantly less in newborn males than in three-month-old male infants and adults. The frequency of Y chromatin-positive cells on day 0 was 36.16 +/- 9.11% and then increased daily. At one month after birth the frequency was 55.07 +/- 9.29%, which was not significantly different from that in adult males (57.08 +/- 5.97%).

Adult↗
PubMed1978

Quinacrine and acridine-R banding without a fluorescence microscope.

A technique is described in which a standard fluorescence microscope equipped with a high-pressure mercury lamp is replaced with an ordinary laboratory microscope fitted with a quartz-iodine lamp. A dark field condenser and a set of three filters, including an FITC interference filter, complete a 'fluorescence' microscope. The microscope has proved itself satisfactory in the study of Y-chromatin, chromosome Q-bands including Q-polymorphism, and acridine-R band. It is very easy to operate and does not emit ultraviolet light, which might harm operators. Total cost of the quartz-iodine lamp's outfit, filters, and a dark-field condenser is much less than that of a standard fluorescence microscope. The cost is especially low when a laboratory microscope with a quartz-iodine lamp is already at hand. Spectrofluorometric studies of QM and Q indicate that the present system will show even better performance if an interference filter with a transmission range of about 400 to 440--450 nm is designed and used in combination with a 455--475 nm barrier filter.

Acridines↗