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Biomedical subjects

N Wang

Publications and source records attributed to N Wang.

At least 487 records · Page 27Linked to original sources
PubMed1982

Recombinant inversion chromosomes in phenotypically normal chickens.

Some progeny resulting from interbreeding of individuals heterozygous for a pericentric inversion of chromosome 1 in the chicken have the two complementary types of recombinant chromosomes arising from a single crossing-over within the inverted segment. These individuals are capable of reproduction. Their progeny can have one or the other of the two recombinant chromosomes or, if crossing-over occurs, either a normal or an inversion chromosome.

Animals↗
PubMed1982

Chromosomal replication asynchrony of a human breast carcinoma cell line. I. studied by continuous BrdU incorporation and G-banding analysis.

Continuous BrdU incorporation and the Giemsa staining technique were used to study the cell cycle kinetics of a human breast tumor cell line. It was found that the interchromosomal replication pattern of the neoplastic cell was significantly different from that of normal cells in two respects. First, the pattern is highly asynchronous; within a single cell there are chromosomes at different replication cycles; that is, some chromosomes complete their DNA replication before others begin. Second, the replication schedule for the chromosomes, as identified by superimposing the BrdU-Giemsa technique on the trypsin G-banding technique, is relatively consistent within the cell line but differs from that of normal cells. Some chromosomes that replicate late in normal human lymphocytes and fibroblasts replicate early in this cell line. In contrast to the unusual interchromosomal replication pattern, gross analysis of the intrachromosomal replication schedule shows no apparent difference from that reported for normal cells. The asynchrony phenomenon reported here may be associated with the etiology of aneuploidy in neoplasia.

Azure Stains↗
PubMed1982

Retinoblastoma and its association with a deletion in chromosome #13: a survey using high-resolution chromosome techniques.

To our knowledge, 20 cases of retinoblastoma associated with a chromosome #13 aberration have been reported. The present study utilized high-resolution prophase banding analysis of 12 additional retinoblastoma patients to determine the occurrence of chromosome aberrations and identify consistently associated clinical abnormalities. Six male and six female patients were studied representing seven cases of bilateral and five cases of unilateral retinoblastoma. One case of unilateral and two cases of bilateral retinoblastoma and detectable cytogenetic abnormalities, all involving an interstitial deletion of 13q14 on the long arm of one chromosome #13. In all five unilateral cases the tumor manifested in the left orbit, and in all seven bilateral cases the left eye was at a more malignantly advanced stage than the right eye. All three cases with a chromosome abnormality had varying degrees of developmental and/or mental retardation, along with at least one other congenital abnormality. In addition to the 12 cases of retinoblastoma, a patient with severe ophthalmologic abnormalities and mild congenital anomalies was studied by the prophase banding technique and found to be partially trisomic for the 13q14 region with gene loci for optic development and indicate that cytogenetic abnormalities may occur even more frequently in retinoblastoma than indicated by the small number of cases reported in the literature.

Child, Preschool↗
PubMed1982

Differential induction of sister chromatid exchange by chemical carcinogens in lymphocytes cultured from patients with solid tumors.

Three carcinogens with different requirements for activation were used to generate sister chromatid exchange (SCE) in cultured lymphocytes from 22 untreated patients with solid tumors. These data were compared to SCEs produced by incubating lymphocytes, from 44 normal persons, with the same carcinogens. In vitro treatments with butadiene epoxide (0.125 micrograms/ml) show no significant differences in the SCEs generated. However, in vitro treatment with mitomycin-C (0.04 micrograms/ml) did induce significant differences (p less than 0.05) in the distribution of the SCE scores. Treatment of the cultured cells with benzo(a)pyrene (10 micrograms/ml), a carcinogen requiring extensive metabolic activation, significantly (p less than 0.001) altered the distribution of the SCEs generated in vitro. The SCE data suggest that metabolic activities play an important role in the processing of carcinogens in solid tumor patients.

Adolescent↗
PubMed1982

Characterization of high- and low-metastatic clones derived from a methylcholanthrene-induced murine fibrosarcoma.

A methylcholanthrene-induced fibrosarcoma (3AM) and several of its clones were evaluated for pulmonary metastasis, growth rate, and chromosome composition. Heterogeneity was observed in the three parameters, and no correlation was found between growth rate and metastatic potential. Furthermore, three clones (10, 34, and 27) were identified with distinctive, high or low, metastatic potential and marker chromosomes. The marker chromosomes characteristic for each clone were identified in the early passages of the parental 3AM line, indicating the preexistence of the different cell types in the original neoplasm. The three clones were then characterized as to tendency to adhere to vascular endothelium, immunogenicity, and antigenic specificity. Clone 10, with two large metacentric markers (T2, 4 and T10, 15) and the highest metastatic potential (221 foci/lung), expressed the highest endothelial attachment and immunogenicity. Clone 27 was characterized with an extremely low rate of metastasis (nine foci/lung) and a T2, 7 large acrocentric marker, while clone 34 was characterized with a moderate rate of metastasis (107.5 foci/lung) and a T4, 16 acrocentric marker. Antigenically, clone 10 cross-reacted with clones 34 and 27 and 3AM, while clones 27 and 34 cross-reacted with clone 10 and 3AM but not with each other, suggesting that, within the original tumor, there were common tumor antigens shared by some cells but no universal antigen shared by all cells.

Animals↗
PubMed1981

The tadpole-shaped structures in human non-necrotizing granulomas.

We scrutinized the secondary lysosomal vesicle of the epitheloid cell from 9 patients whose biopsy specimens show multiple non-necrotizing granulomas by light microscopy (LM). In 4 of the 9 patients, we found tadpole-shaped structures (TSS) approximately tenfold larger than the size of the mycobacteriophage by transmission electron microscopy (TEM). In addition, we used a plasma etching method on epon-embedded tissue and successfully demonstrated the stereoscopic appearance of the TSS by scanning electron microscopy (SEM). The identified TSS were further analyzed with an X-ray energy dispersive spectrometer for their microchemistry. The TSS appeared to be integral structures by TEM and SEM and did not contain any nonbiologic elements when analyzed with the X-ray energy dispersive spectrometer. Their location as well as their morphologic features and microchemistry suggested that the TSS are a microorganism and related to the formation of the granulomas in our 4 patients.

Adult↗
PubMed1981

Cytogenetic evidence for premeiotic transformation of human testicular cancers.

To determine the point at which transformation of the germ cell occurs during meiosis in nonseminomatous testicular cancer, the sex chromosome compositions of 15 cell lines derived from primary tumors or metastases of 12 patients with testicular cancer were analyzed by trypsin G-banding analysis and Y-body staining. The simultaneous existence of both X- and Y-chromosomes in a single cell has been confirmed in 14 cell lines. This suggests that transformation of the cell occurs before the first meiotic division because it is known that segregation of X- and Y-chromosomes occurs during the first meiotic division. An incidental finding was the presence of Barr bodies in some cell lines containing more than one X-chromosome, which is consistent with the known primitive nature of testicular cancer and its ability to differentiate independently from the male host.

Cell Differentiation↗
PubMed1980

Alcohol dehydrogenase in Drosophila: isolation and characterization of messenger RNA and cDNA clone.

The mRNA for alcohol dehydrogenase (ADH) in D. melanogaster has been identified by translation in a cell-free system. The in vitro synthesized polypeptide, specifically precipitated by anti-ADH antibody, has identical subunit molecular weight (25,000 daltons) and tryptic peptide profile to the in vivo synthesized ADH. The poly A containing ADH-mRNA has been purified by specific precipitation of ADH-polysomes using anti-ADH antibody and S. aureus. Transformation of E. coli with the dA-tailed ADH-mRNA-complementary DNA hybrid annealed to the dT-tailed pBR322 yielded one plasmid which has been identified as the ADH-cDNA clone. The identification involved hybridization selection of ADH-mRNA and in vitro translation, in situ hybridization to the Adh locus on salivary gland polytene chromosomes and DNA sequencing. This ADH-cDNA plasmid contains 349 bases of the C-terminal protein coding and 180 bases of the 3' untranslated region.

Alcohol Oxidoreductases↗
PubMed1980

Cytogenetic evidence for the absence of an inactivated X chromosome in a human female (XX) breast carcinoma cell line.

Barr body staining procedures were applied directly to the chamber slide cultures of female amniotic cells. WI38 fibroblasts, normal female kidney cells, and a human breast carcinoma cell line, Elco. A high frequency of Barr bodies was found in all the normal female control cells; however, no Barr bodies were observed in the Elco cells. By trypsin G-banding analysis, two normal X chromosomes were identified in all Elco cells. The late DNA replication pattern of the cell line was then studied with the terminal BrdU pulse method. Both X chromosomes in the Elco cell line were found to be euchromatic with a characteristic R-banding pattern; no late-replicating X chromosome was observed. The absence of both a Barr body and a late-replicating heterocyclic X chromosome provides strong cytogenetic evidence that an inactivated X chromosome is absent in the human breast carcinoma cells bearing two X chromosomes.

Breast Neoplasms↗
PubMed1980

Induction of heteroploidy in Gallus domesticus.

Intraperitoneal colcemid injection at the dose level of 0.37 mg/kg applied 3-4 h before the first oviposition produces a high frequency of triploids among the second oviposition eggs laid the first day after colcemid treatment. The triploids, mostly 3A-ZZW type, appear to be as developmentally compatible as contemporary diploids at both embryonic and hatching level. No other kinds of heteroploids besides triploids were found at hatching time even though a high frequency was observed in 24-h embryos.

Aneuploidy↗
PubMed1980

The induction and detection of diploid spermatozoa in Gallus domesticus.

Colcemid at the dose level of 0.37 mg/kg/day was injected intraperitoneally to 3 sexually active chicken males for 3 consecutive days. 10-12 days after the first colcemid injection, 14-25% of the sperm population in the semen samples from the treated males was found to be diploid in DNA content by flow microfluorometric analysis. Cytogeneic and developmental analyses on early embryos indicate that, during the process of spermatogenesis, the male germ cells are most susceptible to colcemid treatment 10-12 days prior to the maturation of the spermatozoa which is equivalent to the primary through secondary spermatocyte stages in chicken males. By the application of an extremely unequal chromosomal translocation as a cytological marker of parentage, it is confirmed that the diploid sperm induced are capable of uniting with a normal haploid or diploid egg to produce a triploid or tetraploid zygote.

Animals↗
PubMed1980

Nonrandom abnormalities in chromosome 1 in human testicular cancers.

Trypsin G banding was performed on metaphase chromosomes from 14 cell lines derived from primary tumors or metastases of 11 patients with testicular cancer. Most of the cell lines, 11 of 14, have a modal number between 51 and 61. All lines have numerical and structural changes involving chromosome 1 with trisomy of the q arm being the common aberration. Break points in chromosome 1 were nonrandom, being concentrated in the regions of p12, q12, p36, and p22, which resulted in morphologically identical marker chromosomes in different cases. These changes probably are not artifacts of cell culture. In one instance, three lines derived from the same patient, one from tissue removed at operation, and two from separate metastases removed at autopsy nearly 3 years later after unsuccessful radiotherapy and chemotherapy had identical chromosome compositions. In another case, lines derived from a primary tumor and a metastasis from the same patient also had identical marker chromosomes. The consistent involvement of chromosome 1 in aberrations may be associated with the highly malignant nature of testicular cancers.

Adult↗