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C Sheehan

Publications and source records attributed to C Sheehan.

At least 37 records · Page 2Linked to original sources
PubMed1995

E-cadherin expression in papillary transitional cell carcinoma of the urinary bladder.

E-cadherin (E-CD), a cell adhesion molecule that plays a diverse role in cell-cell and cell-matrix interaction, has recently been associated with tumor invasion and metastasis. We evaluated the E-CD expression in 55 cases of urinary bladder papillary transitional cell carcinoma using a double-linked immunoalkaline phosphatase procedure on formalin-fixed, paraffin-embedded specimens quantified as percentage positive staining area with the Roche RPW image analyzer (Roche Image Analysis Systems, Elon College, NC). The 10 grade I tumors stained intensely for E-CD (66%) and showed enhanced staining compared with normal transitional epithelium. The 20 grade II lesions stained moderately at 45%, and the 25 grade III lesions showed weak expression of E-CD with a 33% positive stain. This loss of expression for high-grade versus low-grade tumors was statistically significant (P < .02). There was a similar decrease in E-CD expression for high-stage versus low-stage specimens with 30 stage 0 and stage A cases having an average of 51% positive stain and 25 stage B, C, and D cases having an average stain of 33%. This difference was also statistically significant (P < .001). We conclude that loss of expression of E-CD in high-grade, high-stage urinary bladder transitional cell carcinoma is associated with significant bladder wall invasion, indicates potential for metastasis, and may be of clinical value in the assessment of prognosis and planning of therapy for patients with bladder tumors.

Adult↗
PubMed1995

Genomic fingerprinting Acinetobacter baumannii: amplification of multiple inter-repetitive extragenic palindromic sequences.

Acinetobacter species are important nosocomial pathogens. A rapid and sensitive identification system, capable of providing strain identity at the genetic level, is required to identify outbreak strains and facilitate the early implementation of infection control procedures. Repetitive extragenic palindromic (REP) elements, have been identified in numerous bacteria and these genomic sequences provide useful targets for DNA amplification. A method for amplifying inter-REP DNA sequences, REP-multiple arbitrary amplicon profiling (REP-MAAP), is described and applied to 29 Acinetobacter baumannii from clinical samples. Amplified polymorphic DNA patterns were demonstrated for all isolates and those displaying identical REP-MAAP patterns were considered identical at the genetic level. In the spring of 1993, 10 intensive care unit patients had endotracheal colonization with A. baumannii (five with REP-MAAP I and five with REP-MAAP II patterns). These findings suggested nosocomial transmission of organisms which was terminated by standard infection control measures. No further A. baumannii were detected until the winter of 1993 when isolates of different REP-MAAP groups emerged, suggesting that factors other than nosocomial transmission were implicated.

Acinetobacter↗
PubMed1993

Histologic and ultrastructural features of experimental duodenal ulcers in Sprague-Dawley rats.

The histologic and ultrastructural features of a time sequence study of the development, evolution, and healing of acetic acid-induced experimental duodenal ulcer are presented. Duodenal ulcers produced by serosal application of acetic acid featured microvascular injury with progressive disintegration of the tips of the mucosal villi and subtotal necrosis of the duodenal wall. At 3 days ulcers transformed into a chronic state with regenerating epithelium originating from the crypts of the intact bordering mucosa extending toward the center of the ulcers. By 21 days healed ulcers were covered by distorted duodenal surface mucosa. We conclude that this reproducible and standardized model of duodenal ulcer features vascular injury as the earliest microscopic event, that ischemic necrosis leads to ulceration, and that the chronic phase bears morphologic resemblance to human duodenal ulcer.

Animals↗
PubMed1993

Volunteer hospice offers unique & special services.

Two types of hospices exist: medical and volunteer. Medical hospices are constrained by Medicare regulations. Volunteer hospices fill in the gaps that those regulations leave, providing flexible, supportive care. The community that is served by both medical and volunteer hospice programs offers truly comprehensive care to the dying and their families.

Hospices↗
PubMed1991

Ha-ras induction of the invasive phenotype results in up-regulation of epidermal growth factor receptors and altered responsiveness to epidermal growth factor in human papillary transitional cell carcinoma cells.

Recent studies have shown that orthotopic (transurethral) transplantation of human bladder cancer cell lines into nude mice permits tumor growth that more accurately reflects their clinical malignant status in the original host. We have previously demonstrated that transfection and overexpression of normal or mutated c-Ha-ras genes into a noninvasive human papillary transitional cell carcinoma cell line confer upon these cells an invasive phenotype in vivo with behavior remarkably similar to the clinical behavior of high grade bladder carcinomas. Since elevated expression levels of the epidermal growth factor receptor (EGF-R), in addition to that of c-Ha-ras, have been correlated with transitional cell carcinoma progression, we sought to determine whether up-regulation of the EGF-R had occurred in the invasive high ras expressors and if so, what functional significance this might have. Our results show that invasive cell lines which overexpress the c-Ha-ras gene also have increased epidermal EGF-R expression. This was found to occur at both the protein and mRNA levels, and analysis of the EGF-R promoter/enhancer sequences has revealed a putative AP-1 site which may possibly enhancer sequences has revealed a putative AP-1 site which may possibly serve as a ras response element. In addition, we found that the cells overexpressing the EGF-R had acquired a positive sensitivity to the stimulatory mitogenic effects of EGF. Hence, the results obtained suggest a role for either a normal or a mutated overexpressing Ha-ras in up-regulating the surface EGF-R, possibly through an AP-1 site during human bladder carcinoma progression; they also highlight the potential that EGF may have in cooperating with this EGF-R up-regulation to help mediate enhanced tumor growth.

Blotting, Northern↗
PubMed1991

Dominance of metastatically competent cells in primary murine breast neoplasms is necessary for distant metastatic spread.

We have previously shown, using tumor cell populations genetically tagged by random integrations of plasmid DNA, that metastatically-competent clonal cell variants have a strong growth advantage within primary tumors over their non-metastatic counterparts. As a result, primary tumors can become overgrown by the progeny of such cells, a process referred to as "clonal dominance" of primary tumors by metastatically-competent cells. Because of the well-known "metastatic inefficiency" of the multi-step cascade process of spread and growth, clonal dominance within primary tumors may be necessary for distant metastatic spread or increase the probability of its occurrence. To examine this hypothesis mice were inoculated s.c. with mixture of non-metastatic and genetically tagged, metastatically-competent mouse mammary carcinoma cells in defined ratios, but always containing an excess of the unmarked non-metastatic population. Progressive overgrowth of the metastatic subpopulation was monitored as a function of time by Southern analysis of DNA obtained from mixed primary tumors. This allowed us to evaluate the effects that surgical removal of the primary tumor had before, during and after effective clonal dominance, and what influence this had on the subsequent formation of distant metastases. Surgical removal of primary tumors before metastatic clonal dominance resulted in a low (0.25%) frequency of lung metastases, whereas removal just 1 or 2 weeks later during or after clonal dominance was achieved resulted in a high (75-100%) frequency of such metastases. Our results support the hypothesis that dominance of primary tumors by metastatically competent cells may be necessary for distant metastatic spread, and also suggest that clonal interactions play a significant role in modulating the metastatic ability of tumor cells in vivo.

Adenocarcinoma↗
PubMed1991

Cloning and overexpression of TGF-beta 1 cDNA in a mammary adenocarcinoma: in vitro and in vivo effects.

It has been suggested that transforming growth factor beta (TGF-beta) may be a potential negative autocrine growth regulator of carcinomas including mammary carcinomas. To directly test this hypothesis we have cloned and expressed human TGF-beta 1 cDNA in a murine mammary adenocarcinoma which is normally growth-inhibited by addition of exogenous TGF-beta in vitro. A number of transfectants over-expressing the foreign TGF-beta 1 mRNA were selected and compared to transfectants which did not overexpress the exogenous TGF-beta 1 cDNAS. Cell lines overexpressing the transfected TGF-beta 1 mRNA were found to produce total levels of TGF-beta 7 to 10 fold greater than the parental cells or control transfected clones. However, when levels of active fractions of TGF-beta were compared in cell lines overexpressing TGF-beta 1 to those which did not, no differences were found. This suggests that the activation mechanism is not necessarily induced or altered by increasing levels of latent TGF-beta 1 production in a given tumor cell line. The basal in vitro doubling time of TGF-beta 1 overexpressing clones was identical to the control populations. Similarly, in vivo tumor growth rates after s.c. injection were similar to that of the parental line. Thus the precise role of TGF-beta in mediating either the in vitro or in vivo growth control of a sensitive mammary adenocarcinoma cell line remains unclear. It may be that cellular over-secretion of latent TGF-beta must be coupled with enhanced cellular TGF-beta activation prior to any observed effect on growth rate in vitro or in vivo; this latter event may constitute the "rate-limiting" step of TGF-beta activity on tumor behavior.

Adenocarcinoma↗
PubMed1990

A rapid latex agglutination assay for the determination of plasma fibrinogen.

A monoclonal antibody to intact fibrinogen has been employed to develop a rapid latex agglutination assay for the estimation of plasma fibrinogen. The monoclonal antibody, 45J, recognizes an epitope located in the mid-section of the carboxy terminal end of the A alpha-chain. The epitope is destroyed by plasmin digestion of fibrinogen and there is no immunoreactivity with soluble cross-linked fibrin degradation products. The latex agglutination assay developed with the antibody is unaffected by aprotinin or anticoagulants, such as citrate, heparin or EDTA. When this method was compared with functional clotting assays, excellent correlation was observed with normal and pathological samples. After sample collection and dilution, the assay takes just two minutes to complete. Therefore, this procedure offers a simple and rapid assay for the measurement of intact fibrinogen in plasma.

Animals↗
PubMed1985

Evaluation of five kits for detecting choriogonadotropin in urine.

We report an evaluation of the performance characteristics, accuracy, and sensitivity of five test kits designed to detect human choriogonadotropin (hCG) in urine: "Sensitex" (latex agglutination inhibition), "beta-Neocept" (hemagglutination inhibition), "Duoclone" (direct agglutination), "Tandem-Visual HCG" (enzyme immunoassay), and "Sensichrome" (enzyme immunoassay). For comparison, all specimens and dilutions were also quantified by a radioimmunoassay. The accuracy of these kits was excellent and the manufacturers' stated sensitivity was confirmed. We conclude that the enzyme immunoassay method is the most sensitive procedure for qualitatively detecting hCG.

Chorionic Gonadotropin↗
PubMed1983

Persistent baculovirus infections: Spodoptera frugiperda NPV and Autographa californica NPV in Spodoptera frugiperda cells.

Establishment of a persistent infection of Spodoptera frugiperda nuclear polyhedrosis virus (NPV) in Spodoptera frugiperda (S.f.) cells occurred in three phases: the first phase was characterised by high levels of cell infection and death, the second phase by decreasing cell infection levels leading to the final phase where less than one per cent of the cells were infected during any subculture. The virus persisted at this level of infection provided the cells were maintained by regular subculturing and incubated at the optimum growth temperature of 27 degrees C. Because of the low proportion of cells infected, cultures of virus-free cells could be selected ('cured') by dilution of the persistent infection without the use of viral antiserum. Unlike the parent S.f. cells, cultures of cured cells were partially resistant to infection with S. frugiperda NPV or infection with an unrelated baculovirus Autographa californica NPV. A. californica NPV, which is cytolytic for the parent S.f. cell line, established a persistent infection in the cured cells. The establishment pattern was similar to that previously found for S. frugiperda NPV and only one to five per cent of the cells were infected at equilibrium. Cured cells from the A. californica NPV persistent infection were highly resistant to infection with both S. frugiperda NPV and A. californica NPV. All attempts to find a viral interference phenomenon to explain the resistance of the cured cells were unsuccessful. All cell types adsorbed virus equally well. Slower growth of S.f. cells cured from the persistent A. californica NPV infection is the only difference so far observed between any of the S.f. cell types.

Animals↗
PubMedDate not supplied

DNA amplification fingerprinting (DAF) applied to the investigation of Acinetobacter baumanii isolated from intensive care unit patients.

Acinetobacter are important emerging nosocomial pathogens. In this paper thirteen Acinetobacter baumanii from intensive care patients were isolated. These were initially typed using the API-20 NE biotyping system and antibiogram analysis. Results obtained using these methods failed to convincingly characterise the organisms. In this report a method to characterise these Acinetobacter baumanii isolates is described, which utilises a modified polymerase chain reaction (PCR), capable of generating genomic fingerprints, known as DNA amplification fingerprinting (DAF). Purified chromosomal DNA of cultured clinical isolates of Acinetobacter baumanii were subjected to DAF using the M13 universal sequencing primer. Polymorphic DNA bands produced, were visualised after agarose gel electrophoresis and ethidium bromide staining. Results demonstrated that six of the thirteen clinical isolates represented one group and a second group of two isolates displayed identical fingerprint patterns. The remaining four organisms were all unique. This genotype based method is rapid, simple, reproducible and may have potential as a means of specifically typing Acinetobacter spp. allowing the route(s) of nosocomial transmission to be identified and to assess the efficiency of instituted infection control measures.

Acinetobacter↗