Chromatin texture, which partly reflects nuclear organization, is evolving as an important parameter indicating cell activation or transformation. In this study, chromatin pattern was evaluated by image analysis of the electron micrographs of follicular and papillary carcinoma cells of the thyroid gland and tested for discrimination of the two neoplasms. Digital grey images were converted from the electron micrographs; nuclear images, excluding nucleolus and intranuclear cytoplasmic inclusions, were obtained by segmentation; grey levels were standardized; and grey level histograms were generated. The histograms in follicular carcinoma showed Gaussian or near-Gaussian distribution and had a single peak, whereas those in papillary carcinoma had two peaks(bimodal), one at the black zone and the other at the white zone. In papillary carcinoma. the peak in the black zone represented an increased amount of heterochromatin particles and that at the white zone represented decreased electron density of euchromatin or nuclear matrix. These results indicate that the nuclei of follicular and papillary carcinoma cells differ intheir chromatin pattern and the difference may be due to decondensed chromatin and/or matrix substances.
Carcinoma, Papillary ; Chromatin* ; Discrimination (Psychology)* ; Euchromatin ; Heterochromatin ; Inclusion Bodies ; Normal Distribution ; Nuclear Matrix ; Thyroid Gland*

PURPOSE: Telomeres, special protein and tandem repeat DNA structure that cap the ends of linear eukaryotic chromosomes, are essential for chromosome structure and stability. Human telomeric DNA is known to shorten by 30~200 bp with each somatic cell division. However, the phase of telomere changes has not been studied extensively. METHODS: Telomere length was analyzed in the peripheral blood mononuclear cells (PBMCs) of 39 normal controls aged from newborn to 72 years by Southern blot hybridization using PharMingen's TeloQunatTM Telomere Length Assay Kit (Becton Dickinson Co.). RESULTS: The mean telomere length of the population was 9.68 kb (range, 5.65~14.40 kb). The length (kb) decreased with age (A) by the following regression: T=10.86 0.04 A (T=telomere length in kb; A=age in years) (r= 0.38; P=0.016). The mean telomere lengths according to age groups were: 10.26 kb for less than 15 years; 9.92 kb for 16 to 40 years; 8.03 kb for over 40 years. The telomere length of over 40 years was significantly shorter than that of less than 15 years (P=0.013), and than that of 16 to 40 years (P=0.011). The phase of telomere changes was evaluated by age subgroups. The shortening was fastest in individuals of age <5, while the length showed a plateau or slight increment in age group between 5 to 35. The length decreased steadily with age by the regression of 12.43+/-0.07 A (r= 0.500; P=0.034) in age group over 35. CONCLUSION: Telomere length of PBMCs decreases with age, and the different phase of telomere length shortening may suggest that the shortening of telomere is not a constant process over lifespan, but a dynamic process that is differently regulated in age groups.
Blotting, Southern ; Cell Division ; Chromosome Structures ; DNA ; Humans ; Infant, Newborn ; Tandem Repeat Sequences ; Telomere Shortening* ; Telomere*

BACKGROUND: Malignant cell nuclei, in general, have increased amounts of heterochromatin and decreased electron densities of euchromatin, making the chromatin pattern coarser than that of benign cell nuclei. The chromatin pattern in benign and malignant cells, however, is barely explained in terms of molecular structure. In this study, the chromatin pattern of metaplastic and carcinomatous squamous cells of the uterine cervix was correlated with transcriptional activity by ultrastructural autoradiography. METHODS: Punch-biopsied tissues were cultured with 3H-uridine for 5 minutes and processed for electron microscopy. Thin sections of the tissues on nickel grids were covered with photosensitive emulsion and kept cold in a dark room for 10 to 16 weeks. After development and staining, the tissues were observed by electron microscopy. RESULTS: The nuclei of the metaplastic squamous cells consisted mostly of euchromatin. A few silver grains were observed, mainly at the periphery of the nuclei. The nuclei of the carcinomatous cells had increased amounts of heterochromatin along the nuclear membrane, and also in the euchromatin area. Silver grains were observed mainly at the boundary between the heterochromatin and euchromatin. CONCLUSION: These findings suggest that an increased amount of heterochromatin in carcinomatous cells results in an increase of the boundary area between the heterochromatin and euchromatin, an area which may be a transcriptionally active site.
Autoradiography ; Catalytic Domain ; Cell Nucleus ; Edible Grain ; Cervix Uteri ; Chromatin ; Euchromatin* ; Female ; Heterochromatin* ; Microscopy, Electron ; Molecular Structure ; Nickel ; Nuclear Envelope ; RNA, Messenger* ; Silver

OBJECTIVETo detect subtelomeric rearrangement in patients with idiopathic mental retardation/developmental delays (MR/DD) and to provide new methods and evidence for the etiologic diagnosis of MR/DD in China.

METHODS1.

INCLUSION CRITERIA(1) Moderate to severe MR/DD; (2) no definite perinatal brain injury; (3) no toxication, hypoxia, infection of central nervous system and cranial trauma; (4) routine karyotyping is normal; (5) no evidence of typical inherited metabolic disorder or specific neurodegenerative disorders from cranial neuro-imaging and blood/urinary metabolic diseases screening; (6) no mutation of FMR1 gene in male patients plus one of the following criteria: (1) positive family history of MR; (2) positive family history of miscarriages and perinatal deaths; (3) abnormal growth; (4) facial and non-facial dysmorphism. 2. Multiplex ligation-dependent probe amplification (MLPA) and fluorescence in situ hybridization (FISH) were applied to detect subtelomeric rearrangements in patients and their parents.

RESULTSFour cases were identified from 39 selected cases with subtelomeric rearrangements (10%), including der (2) t (2; 4) (pter; pter), 11qter del, 8pter del, and 15p11.2 del. The first two abnormalities of chromosome subtelomeric regions have not been reported yet. All these cases had some small dysmorphologies, such as microcephaly, hypertelorism, low nasal bridge, and three of them had hypotonia. One case had recurrent seizure and abnormal behavior (laughter not associated with happiness), and another case with dysgenesis of corpus callosum and septum pellucidum. Family and perinatal histories were normal for all cases. All chromosome rearrangements were de novo which were not from the parents with normal phenotype. It indicated that all these abnormal rearrangements should be responsible for the mental retardation phenotype of these patients. The phenotype of case 4 was similar to Angelman syndrome, his deletion was actually a kind of interstitial rearrangements. It will be confirmed by DNA methylation test to determine whether the deleted allele was of maternal origin.

CONCLUSIONSThe subtelomeric rearrangements were found in 10% patients with idiopathic MR. It indicated that subtelomeric rearrangements should be one of major reasons of MR/DD related to genetic factors. Two novel subtelomeric rearrangements were identified. These de novo rearrangements are probably disease related, because they are not inherited from their parents with normal phenotype. The detection should be carried out for all the patients with idiopathic MR/DD with unknown origin, because one cannot figure out the specific signs for subtelomeric rearrangements. Sequentially use of MLPA and FISH is a more efficient and economic method to detect the subtelomeric rearrangements.

Adolescent ; Child ; Child, Preschool ; Chromosome Structures ; DNA Probes ; Female ; Gene Rearrangement ; Humans ; In Situ Hybridization, Fluorescence ; Infant ; Intellectual Disability ; genetics ; Male ; Mutation ; Sequence Deletion ; Telomere ; genetics

OBJECTIVESperm chromatin structure assay (SCSA), as a clinically practical technique for the analysis of DNA damage, is rarely reported in China. This study focuses on the correlation of DNA damage with the pregnancy rate of intrauterine insemination (IUI).

METHODSWe performed semen analysis for 482 couples undergoing IUI, calculated the DNA fragmentation index (DFI) by SCSA, and observed the relationship between DFI and the pregnancy rate of IUI.

RESULTSClinical pregnancy was achieved in 5 (5.26%) of the 95 cases with DFI > 25%, and in 59 (15.25%) of the 387 cases with DFI < or = 25%. Those with sperm DFI >25% had significantly lower rates of biochemical pregnancy and clinical pregnancy than those with DFI < or = 25% (OR: 0.37, 95% CI: 0.14 - 0.96 and OR: 0.38, 95% CI: 0.16 - 0.97). No significant differences were found in the DFI of 54 cases between the first and the second cycle ([15.05 +/- 7.98]% vs [17.25 +/- 12.18]%, P > 0.05). Sperm DFI was significantly negatively correlated with sperm concentration, sperm motility and total progressively motile sperm count (P < 0.01).

CONCLUSIONThe pregnancy rate of IUI is significantly lower in couples with DFI >25% than in those with DFI < or = 25%. Sperm DFI obtained from SCSA is partly correlated with sperm concentration and motility, and it is a robust predictor of the IUI outcome.

Adult ; Chromatin ; Chromosome Structures ; DNA Fragmentation ; Female ; Humans ; Insemination ; Insemination, Artificial ; methods ; Male ; Pregnancy ; Pregnancy Outcome ; genetics ; Pregnancy Rate ; Reproductive Techniques, Assisted ; Sperm Count ; Sperm Motility ; Young Adult

Animals ; Centromere ; metabolism ; Chromosomal Proteins, Non-Histone ; metabolism ; Mice ; Models, Molecular ; Synaptonemal Complex ; metabolism

No abstract available.
DNA* ; Nucleolus Organizer Region*

No abstract available.
Chromosome Aberrations* ; Embryonic Structures* ; Humans ; Male* ; Preimplantation Diagnosis* ; Sperm Injections, Intracytoplasmic*

OBJECTIVETo determine the genome structure of human telomeric repeat binding factor 1 (TERF1) and its pseudogenes.

METHODSSequences were obtained from GenBank and analyzed using the BLAST program and other relevant biology program (Sequencher, DNA Strider and Autoassembler, etc) to determine the genome and pseudogenome structure of TERF1. PCR and sequencing were performed to verify the results.

RESULTTERF1 gene which mapped to 8q13 was divided into 10 exons. It had four processed pseudogenes located on chromosome 13, 18, 21 and X respectively (Psi TERF1-13 Psi TERF1-18 Psi TERF1-21 and Psi TERF1-X ). They were entire intronless TERF1 genes which lacked some exons. Three homologous fragments of at least 60 kb on the flanking region of Psi TERF1-13, Psi TERF1-18 and Psi TERF1-21, respectively were noted.

CONCLUSIONTERF1 gene has 10 exons. It has four processed pseudogenes which are located on chromosome 13, 18, 21, and X, respectively. Large homologous fragments that belong to the recently duplicated segments are transchromosomal duplications.

Chromosome Mapping ; Genetic Structures ; Humans ; Pseudogenes ; Telomeric Repeat Binding Protein 1 ; genetics

Programrned cell death (PCD), or apoptosis, is a process by which cells die in response to specific physiological and toxicological signals. This genetically programmed form of cellular suicide is intirnately involved in many biological processes including growth, metamorphosis, embryogenesis, and oncogenesis. Cells undergoing PCD in normal and neoplasmic tissues display the following biochemical and morphological features: internucleosomal DNA fragmentation, reduced cell volume, condensed chromatin in nucleus, zeiosis and generation of apoptotic bodies containing intact organelles and plasma rnembrane. Hybridoma cell production, resulting from the fusion of myeloma cells with antibody producing spleen cells, is widely used in various fields of life science. This technique requires hypoxanthine guanine phosphoribosyl transferase (HGPRT) deficient mutant myeloma cell line as a fusion partner. When these mutants cell is treated with aminopterin plus hypoxanthine-thymidine (HAT) after the cell fusion they are selectively and efficiently eliminated remaining fused hybridoma celis. But there hasn't been any report regarding the selective elimination mechanism of this HGPRT mutant myeloma cell. By using HGPRT myeloma P3-X 63-Ag8.653 (V653) as a model system, this study demonstrated that PCD was induced by aminopterin treatment of this V653 cell line. And the sequential ultrastructural changes during this death process were observed by using electron microscope. When V653 cells were incubated with 0.4 uM aminopterin, DNA fragmentation was detectable after 3 hours and peaked between 12 and 18 hours of aminopterin treatment and the cell viability decreased in a time dependant manner. V653 cells incubated with amiopterin showed following ultrastructural changes during the death process. Dilatation of rough endoplasmic reticulum (RER) and detachment of ribosomes were the earliest ultrastructural changes and first seen after 30 minute incubation. Dilatation of perinuclear cisternae began to appear after 1 hour and deformation of nucleoplasm such as decreased electron density of perinuclear heterochromatin and increased electron density of euchromatin were seen after 3 hours. Increased electron density of cytoplasm, decreased cell volume, condensation of chromatin and apoptotic bodies were observed in many cells after 9 hours but vacuolation by severe dilatation of RER was seen in some cells. 24 hours after incubation with aminopterin, many cells showed typical form of apoptosis characterized by cell shrinkage, increased electron density of cytoplasm and apoptotic bodies. On the contrary, some cells showed different type of cell death characterized by increased cell volume, decreased electron density of cytoplasm, severely dilated RER and apoptotic bodies. In both types of cells, mitochondrial cristae and limiting membrane of mitochondria are comparatively well preserved. In other cells, nuclei did not show significant changes but there were deformations of mitochondria such as markedly increased electron density and formation of lamella bodies. The death process of V653 cell was not synchronized among cells. The results of this study proved that aminopterin-induced selective elimination of fusion partner V653 myeloma cell is due to PCD. The earliest ultrastructural changes observed in this process were dilatation of RER and detachment of ribosomes. And there were two distinct morphological types in the PCD.
Aminopterin* ; Animals ; Apoptosis* ; Biological Processes ; Biological Science Disciplines ; Carcinogenesis ; Cell Death ; Cell Fusion ; Cell Line ; Cell Size ; Cell Survival ; Chromatin ; Cytoplasm ; Dilatation ; DNA Fragmentation ; Embryonic Development ; Endoplasmic Reticulum, Rough ; Euchromatin ; Female ; Guanine ; Heterochromatin ; Hybridomas ; Hypoxanthine ; Hypoxanthine Phosphoribosyltransferase ; Membranes ; Mice* ; Mitochondria ; Organelles ; Plasma ; Pregnancy ; Ribosomes ; Spleen ; Suicide ; Transferases