No abstract available.
Ring Chromosomes*

No abstract available.
Congenital Abnormalities* ; Ring Chromosomes*

PURPOSE: It was studied that the relationship between radiation dose, dose rate and the frequency of chromosomal aberrations in peripheral lymphocytes. METHODS AND MATERIALS: Peripheral lymphocytes were irradiated in vitro with 6 MeV X-ray at dose ranges from 50 cGy to 800 cGy. The variations of the frequency of chromosomal aberrations were observed according to different radiation dose rate from 20 cGy/min to 400 cGy/min at constant total dose of 400 cGy which it was considered as factor to correct biological radiation dose measurement. RESULTS: The yields of lymphocytes with chromosomal aberrations (dicentric chromosome, ring chromosome, acentric fragment pairs) are 0% at 50 cGy, 9% at 100 cGy, 20% at 200 cGy, 27% at 300 cGy, 55% at 400 cGy, 88% at 600 cGy, and 100% at 800 cGy. The value of Ydr is 0.000 at 50 cGy, 0.093 at 100 cGy, 0.200 at 200 cGy, 0.364 at 300 cGy, 0.612 at 400 cGy, 2.040 at 600 cGy, and 2.846 at 800 cGy. The relationship between radiation (D) and the frequency of dicentric chromosomes and ring chromosomes (Ydr) can be expressed as Ydr=0.188x10-2/GyxD+0.422x10-4/Gy2xD2. The value of Qdr is 0.000 at 50 cGy, 1.000 at 100 cGy, 1.000 at 200 cGy, 1.333 at 300 cGy, 1.118 at 400 cGy, 2.318 at 600 cGy, and 2.846 at 800 cGy. When 400 cGy is irradiated with different dose rate each of 20, 40, 60, 80, 100, 160, 240, 320, and 400 cGy/min, Ydr is each of 0.982, 0.837, 0.860, 0.732, 0.763, 0.966, 0.909, 1.006, and 0.806, and Qdr is each of 1.839, 1.565, 1.654, 1.333, 1.381, 1.750, 1.6000, 1.710, and 1.318. CONCLUSION: There are not the significant variations of Ydr and Qdr values according to different dose rate. And so radiation damage is influenced by total exposed radiation doses and is influenced least of all by different dose rate when it is acute single exposure.
Chromosome Aberrations* ; Lymphocytes* ; Ring Chromosomes

Chromosomal aberration analysis, as a basis for biological radiation dosimetry, was performed for radiation dose ranges below 150 cGy. The yield, ratio of lymphocytes with dicentric and/or ring chromosomes, was 0, 0, 0.4, 0.5, 0.6, 0.8, 1.8, 5.5, 8.0, and 18.5% for 0, 5, 10, 15, 20, 25, 50, 75, 100 and 150 cGy, respectively. The Qdr, ratio of dicentric and ring chromosomes in total lymphocytes, was 0, 0, 0.004, 0.005, 0.006, 0.009, 0.018, 0.055, 0.084 and 0.207, respectively. The Qdr, ratio of dicentric and ring chromosomes in lymphocytes with aberration, was 1.0 for the radiation doses up to 75 cGy and 1.05 and 1.11 for 100 and 150 cGy, respectively. From the results, it seems possible to estimate radiation dose from Ydr when the exposure is 25 cGy or more. All the 5 radiation workers studied, with exposure much less than 1 mSv per month, had chromosomal aberrations. And acentric fragment pairs, in addition to dicentric and ring chromosomes, showed good dose response relationship and so may be useful for biological dosimetry for low dose radiation exposure, accidental or occupational.
Chromosome Aberrations* ; Lymphocytes ; Radiometry ; Ring Chromosomes

Chromosomes, Human, Pair 14 ; Humans ; Ring Chromosomes ; Syndrome

OBJECTIVETo investigate the clinical phenotype and genetic characteristics of an azoospermia patient with ring 22 chromosome syndrome.

METHODSWe analyzed the clinical data of an azoospermia patient with ring 22 chromosome syndrome and reviewed relevant literature.

RESULTSThe patient was a short 29-year-old male, with bilateral testes small in size and soft in texture. Seminal examination indicated azoospermia. Chromosome analysis showed the karyotype of the patient to be 46, XY, r (22) (p11, q25). The level of testosterone was low, and the testicular tissue was brittle and easy to break. Pathological microscopy revealed reduced number of Sertoli cells and germ cells in the seminiferous tubules and thinner layers of cells. All the germ cells were spermatogonia. Neither spermatocytes nor sperm cells were found, which suggested complete spermatogenic failure. Mild interstitial fibrosis was visible in part of the seminiferous tubule walls.

CONCLUSIONPatients with ring 22 chromosome syndrome usually represent normal clinical phenotypes. However, this kind of genetic abnormality often induces severe testicular damage and spermatogenic arrest, which may result in azoospermia.

Adult ; Azoospermia ; etiology ; genetics ; Chromosomes, Human, Pair 22 ; Humans ; Male ; Oligospermia ; Ring Chromosomes ; Spermatogenesis ; Spermatogonia ; Syndrome

OBJECTIVETo explore the genetics mechanism for the phenotypic variability in a patient carrying a rare ring chromosome 9.

METHODSThe karyotype of the patient was analyzed with cytogenetics method. Presence of sex chromosome was confirmed with fluorescence in situ hybridization. The SRY gene was subjected to PCR amplification and direct sequencing. Potential deletion and duplication were detected with array-based comparative genomic hybridization (array-CGH).

RESULTSThe karyotype of the patient has comprised 6 types of cell lines containing a ring chromosome 9. The SRY gene sequence was normal. By array-CGH, the patient has carried a hemizygous deletion at 9p24.3-p23 (174 201-9 721 761) encompassing 30 genes from Online Mendelian Inheritance in Man.

CONCLUSIONThe phenotypic variability of the 9p deletion syndrome in conjunct with ring chromosome 9 may be attributable to multiple factors including loss of chromosomal material, insufficient dosage of genes, instability of ring chromosome, and pattern of inheritance.

Chromosomes, Human, Pair 9 ; genetics ; Female ; Humans ; Infant ; Karyotype ; Male ; Ring Chromosomes ; Sex Chromosome Disorders ; genetics

Child, Preschool ; Chromosomes, Human, Pair 18 ; Female ; Human Growth Hormone ; deficiency ; Humans ; Ring Chromosomes

Child, Preschool ; Chromosomes, Human, Pair 11 ; Female ; Humans ; Kidney Neoplasms ; genetics ; Ring Chromosomes ; Wilms Tumor ; genetics

Child ; Chromosomes, Human, Pair 14 ; Drug Resistant Epilepsy ; drug therapy ; genetics ; Humans ; Male ; Ring Chromosomes