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Biomedical subjects

C S Cooper

Publications and source records attributed to C S Cooper.

At least 91 records · Page 5Linked to original sources
PubMed1994

Instability of short tandem repeats (microsatellites) in human cancers.

The allele sizes of polymorphic microsatellite repeats in DNA from human cancers were compared to normal DNA from the same patients. In 16 out of 196 paired samples (8%), we found evidence of an extra allele of a different size in the tumour which was not present in the normal DNA. Sequence analysis confirmed that the extra allele originates from the appropriate locus and that the size change is attributable to alteration in the number of repeat units. This form of instability was more common in tri- and tetranucleotide repeats than in dinucleotide repeats. In any single tumour sample only one repeat in the set examined was abnormal, the remainder showing identical patterns in normal and tumour DNA or evidence of allele loss. The pattern of instability in diverse types of cancer differs from that reported in colorectal neoplasms.

Alleles↗
PubMed1994

Identification of novel genes, SYT and SSX, involved in the t(X;18)(p11.2;q11.2) translocation found in human synovial sarcoma.

Human synovial sarcomas contain a recurrent and specific chromosomal translocation t(X;18)(p11.2;q11.2). By screening a synovial sarcoma cDNA library with a yeast artificial chromosome spanning the X chromosome breakpoint, we have identified a hybrid transcript that contains 5' sequences (designated SYT) mapping to chromosome 18 and 3' sequences (designated SSX) mapping to chromosome X. An SYT probe detected genomic rearrangements in 10/13 synovial sarcomas. Sequencing of cDNA clones shows that the normal SYT gene encodes a protein rich in glutamine, proline and glycine, and indicates that in synovial sarcoma rearrangement of the SYT gene results in the formation of an SYT-SSX fusion protein. Both SYT and SSX failed to exhibit significant homology to known gene sequences.

Amino Acid Sequence↗
PubMed1994

Tpr, a large coiled coil protein whose amino terminus is involved in activation of oncogenic kinases, is localized to the cytoplasmic surface of the nuclear pore complex.

From a panel of monoclonal antibodies raised against fractions of rat liver nuclear envelopes (NEs), we have identified an antibody, RL30, which reacts with novel nuclear pore complex (NPC) antigens that are not O-glycosylated. By immunofluorescence staining of cultured cells, RL30 reacts exclusively with the NE in a punctate pattern that largely coincides with that of identified NPC proteins. RL30 labels only the cytoplasmic surface of the NPC in immunogold electron microscopy, predominantly in peripheral regions nearby the cytoplasmic ring. In immunoblots of isolated rat liver NEs and cultured rat cells, RL30 recognizes a 265-kD band, as well as a series of 175-265-kD bands in rat liver NEs that are likely to be proteolytic products of p265. Sequencing of peptides from the 175- and 265-kD RL30 antigens of rat liver revealed that they are both closely related to human Tpr, a protein whose amino-terminal 150-250 amino acids appear in oncogenic fusions with the kinase domains of the met, trk, and raf protooncogenes. We found that in vitro translation of human Tpr mRNA yields a major 265-kD band. Considered together, these data indicate that the 265-kD RL30 antigen in the NPC is the rat homologue of Tpr. Interestingly, Tpr contains an exceptionally long predicted coiled coil domain (approximately 1600 amino acids). The localization and predicted structure of Tpr suggest that it is a component of the cytoplasmic fibrils of the NPC implicated in nuclear protein import. Immunofluorescence microscopy shows that during NPC reassembly at the end of mitosis, Tpr becomes concentrated at the NE significantly later than O-linked glycoproteins, including p62. This indicates that reassembly of the NPC after mitosis is a stepwise process, and that the Tpr-containing peripheral structures are assembled later than p62.

Amino Acid Sequence↗
PubMed1993

Predictors of laparoscopic complications after formal training in laparoscopic surgery.

OBJECTIVE: To evaluate the relationship between laparoscopic complication rates and surgeon-dependent variables following a laparoscopic training course. DESIGN: Participants were surveyed regarding their interval laparoscopic experience 3 months and 12 months after the course. PARTICIPANTS: Course participants/survey respondents represented a cross section of urologic surgeons in the United States. A total of 181 individuals (61% of 297 participants) completed and returned the 3-month questionnaire. A total of 128 surgeons responded to the 12-month questionnaire (78.5% of 163 participants). MAIN OUTCOME MEASURE: Logistic regression analysis tested the relationship between surgeons' complication rates and study variables. RESULTS: At 3 months, surgeons who performed clinical procedures without additional training were 3.39 times more likely to have at least one complication compared with surgeons who sought additional training (P = .03). At 12 months, surgeons who had attended the training course alone, were in solo practice, or performed laparoscopic surgery with a variable assistant were 4.85, 7.74, and 4.80 times more likely, respectively, to have had a complication than their counterparts who attended the course with a partner, were in group practice, or operated with the same assistant (P = .004, P = .0008, and P = .0015, respectively). At both 3 and 12 months, laparoscopic complication rates of individual surgeons demonstrated a significant inverse correlation with the number of laparoscopic procedures performed. CONCLUSIONS: The rate of complications associated with the clinical learning curve can be decreased by additional education following an initial course in laparoscopy. An ongoing clinical association with surgeons performing similar procedures decreases long-term complication rates.

Clinical Competence↗
PubMed1992

Preparation and in vitro and in vivo evaluation of quinolones with selective activity against gram-positive organisms.

A series of quinolones were prepared which contained oximes or substituted oximes as replacements for the amine substituents normally found on the pyrrolidine or piperidine fragments of quinolone antibacterial agents. These substituents led to compounds that had selective activity against Gram-positive organisms. These compounds showed in vivo activity against Staphylococcus aureus. Only compound 29 had in vivo activity against Streptococcus pneumoniae.

4-Quinolones↗
PubMed1992

The impact of iatrogenic urothelial trauma on urinary levels of transforming growth factor-alpha.

Growth factors are important regulators of epithelial cell biology. We postulated that iatrogenic bladder manipulations may alter urinary growth factor levels and thereby influence both normal and neoplastic urothelium. Using a rat model we studied the effects of various types of urothelial injury, corresponding to bladder catheterization, cystoscopy, fulguration, and chronic indwelling catheterization (Groups B, C, D, and E respectively) on levels of urinary transforming growth factor-alpha (uTGFa). Urine samples collected circa the time of transurethral bladder manipulation were analyzed for protein, creatinine (Cr), and TGFa. Results in experimental groups were compared to control values (group A). Peak concentrations of uTGFa uniformly occurred on the day of surgery and represented 176%, 196%, 726%, 461% and 916% increases relative to pre-operative values in groups A, B, C, D and E respectively. Total uTGFa (nM/mg. Cr) was maximal on experimental day 0 in groups A, B, C, D and day 2 in group E (102%, 114%, 227%, 290% and 976% change from baseline respectively). Compared to control, levels of uTFGFa were significantly elevated on day 0 in the fulguration group, and day 0 and 2 in the chronic catheterization animals (p less than .05). Nonsignificant elevations of uTGFa relative to control were based in all groups through day 7. The chronic catheterization levels remained significantly elevated, compared to control, over the duration of the study (ANOVA, p less than .05). Urinary protein levels correlated with the severity of the injury and showed a strong positive correlation with uTGFa (p = .0001). This study demonstrated a clear impact of iatrogenic urothelial trauma on urinary levels of TGFa.

Animals↗
PubMed1992

Increased expression and mutation of p53 in choroidal melanoma.

Using CM-1 antibody directed against the human p53 protein, high levels of mutant p53 protein expression were found in 12 out of 18 malignant choroidal melanomas. In contrast, we failed to observe elevated p53 expression, indicating the absence of p53 mutation in seven choroidal naevi, a potentially premalignant condition that can progress to form malignant melanoma. For two choroidal melanomas, we demonstrated that high levels of p53 protein were accompanied by exon 7 mutations. The mutations were found at codon 238, TGT-->TTT and codon 253, ACC-->AGC. These observations suggest that acquisition of abnormalities of the p53 gene may be an important step in the development of malignant melanoma.

Animals↗
PubMed1992

Localization of the synovial sarcoma t(X;18)(p11.2;q11.2) breakpoint by fluorescence in situ hybridization.

A high proportion of synovial sarcomas contain a chromosome translocation t(X;18)(p11.2;q11.2). We have previously used somatic cell hybrids derived from an established cell line, SS255, to map the X chromosome breakpoint to the interval flanked by the markers DXS14 and DXS146. In this study we have examined these hybrids with thirteen additional markers located at Xp11.3-Xcen, by Southern hybridization. Based on these results we have delimited the breakpoint as follows Xpter-DXS228-(UBE1-OATL1-TIMP-DXS226 )-(DXS255-TFE3-ELK1-DXS146)-OATL2- X;18-(DXS14-DXS422-DXS423-DXS674-DXS679)-+ ++Xcen. Confirmation of the breakpoint location has been obtained by analysis of two synovial sarcoma cell lines, SS255 and HA2243, using fluorescence in situ hybridization. A 350kb YAC probe spanning the DXS423 locus hybridized only to the derivative X chromosome, showing that it maps proximal to the breakpoint. Two YAC probes of 300kb and 450kb, containing the OATL2 locus, hybridized to both derivative chromosomes, indicating that these YACs span the translocation breakpoint. Similar results were obtained with both cell lines. The identification of YACs that span the t(X;18) breakpoint now facilitates a strategy for cloning candidate genes from this precisely defined region.

Animals↗
PubMed1992

The human tpr gene encodes a protein of 2094 amino acids that has extensive coiled-coil regions and an acidic C-terminal domain.

We recently provided evidence that the human tpr gene encodes a 726 amino acid protein (designated tpr-S) and identified an alternatively spliced transcript that encodes a larger tpr protein with an extended C-terminal domain. In this study, through isolation and sequencing of tpr cDNA clones, we have established that this alternatively spliced transcript encodes a protein of 2094 amino acids (designated tpr-L). The larger tpr protein is predicted to have extensive regions of alpha-helix and several stretches of a heptad repeat that is characteristic of proteins adopting a coiled-coil conformation. Furthermore the carboxy domain of this protein is very rich in acidic residues and exhibits homology (58-80%) to the acidic regions of several nuclear proteins, including the Drosophila engrailed protein, Escherichia coli RNA polymerase sigma subunit and nucleolin. To gain additional insight into the function of tpr we examined the expression of tpr transcripts in tissues from adult rat. The highest levels of tpr transcripts were observed in testis, lung, thymus and spleen.

Amino Acid Sequence↗
PubMed1992

Nucleotide sequence analysis of human tpr cDNA clones.

In this study we have characterized cDNA clones corresponding to a gene, called tpr, that has been implicated in the activation of the met and raf proto-oncogenes. Sequencing of tpr clones isolated from an HT1080 human fibrosarcoma cell line cDNA library identified an open reading frame (ORF) of 726 amino acids. In addition we have established that alternative splicing can result in the deletion of a 30 bp sequence that spans the translation termination site of this ORF. This modification generates mRNAs encoding a tpr protein that has an extended C-terminal domain. The 726 amino acid tpr protein is predicted to have extensive regions of alpha-helix and has three stretches of a heptad repeat motif that is characteristic of proteins adopting a coiled-coil conformation. The tpr protein exhibits weak homology (28-39%) to the alpha-helical domains of several proteins including tropomyosin, spectrin, laminin B1, the Drosophila glued protein and the tail region of myosin heavy chain.

Amino Acid Sequence↗
PubMed1991

A case of cerebellar medulloblastoma with a single chromosome abnormality.

In the few published karyotypes of human medulloblastoma, multiple chromosome abnormalities have usually been demonstrated. We report a case of medulloblastoma in which only a single structural alteration was observed, namely an unbalanced translocation between chromosomes 1 and 6 resulting in partial 1q trisomy and partial 6q mónosomy. This finding may help define genomic regions that are of importance in development of medulloblastoma.

Cerebellar Neoplasms↗
PubMed1991

The role of non-ras transforming genes in chemical carcinogenesis.

DNA transfection experiments using the NIH 3T3 mouse fibroblast cell line have demonstrated that chemically induced tumors and chemically transformed cell lines frequently contain dominant transforming genes. Although many of the genes detected using the NIH 3T3 transfection-transformation assay are activated versions of H-ras, K-ras, and N-ras, in some experimental systems activated forms of genes such as met and neu that are unrelated to ras have been observed. The activated met gene was originally detected in a human cell line that had been transformed by exposure to N-methyl-N'-nitro-N-nitrosoguanidine. Subsequent studies demonstrated that the met proto-oncogene encodes a novel growth factor receptor and that gene activation involves the production of a chimeric gene in which the regions of met encoding the extracellular and transmembrane domains of the receptor are replaced by the 5'-region of an unrelated gene called trp. The activated neu gene was detected in tumors of the nervous system that arose in mice following transplacental exposure to N-ethyl-N-nitrosourea. The neu gene also encodes a novel growth factor receptor but, in contrast to met, its activation involves a single T:A----A:T point mutation in the region of the neu gene encoding the receptor transmembrane domain. The presence of genetic alterations in chemically induced malignancies has also been assessed in cytogenetic studies and by Southern analysis of DNA from neoplastic cells.(ABSTRACT TRUNCATED AT 250 WORDS)

3T3 Cells↗
PubMed1991

Detection of transforming genes by transfection of DNA from primary soft-tissue tumours.

A series of adult soft-tissue tumours were screened for the presence of activated oncogenes by transfecting tumour DNA into NIH3T3 mouse fibroblasts. In these studies an activated K-ras gene that contained a mutation at the second position of codon 12 (GGT----GAT) was found in a leiomyosarcoma. In addition, following transfection of DNA from a liposarcoma, we identified an activated gene that failed to hybridize to probes prepared from 10 known human oncogenes (K-ras, H-ras, N-ras, ret, met, trk, mas, dbl, raf and hst) that have previously been detected in DNA transfection experiments. BamHI-BamHI fragments of this activated gene of 3.5 and 8.5 kb were cloned from NIH3T3 secondary transfectants using a probe that detects the human alu family of highly repetitive DNA sequences. Repeat-free subclones of these BamHI fragments were used to map this gene to human chromosome 19 (p13.2-q13.3). Our studies also demonstrate that a subclone from one of the BamHI fragments detects a 3.0 kb transcript in primary and secondary transfectants.

3T3 Cells↗