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Biomedical subjects

P May

Publications and source records attributed to P May.

At least 19 recordsLinked to original sources
PubMed1992

Hospital-acquired infection with vancomycin-resistant Enterococcus faecium transmitted by electronic thermometers.

OBJECTIVES: To describe an epidemic of vancomycin-resistant Enterococcus faecium causing bacteremia and bacteriuria, to identify the source of infection, to delineate risk factors associated with acquisition of the organism, and to determine antibiotic sensitivities for the organism. DESIGN: Investigation of an epidemic, including a case-control study. SETTING: Medical-surgical intensive care unit and ward in a university medical center. PATIENTS: Nine patients infected or colonized with vancomycin-resistant Enterococcus faecium and 20 noninfected controls. MEASUREMENTS: Clinical data, environmental surveillance cultures, and in-vitro microbiologic studies. RESULTS: Colonization or infection by vancomycin-resistant E. faecium was associated with an increased duration of treatment with ceftazidime, 13.2 compared with 4.6 days, and a greater number of nonisolated days of hospitalization in the intensive care unit, 19.9 compared with 6.4 days for infected and noninfected patients, respectively (P less than 0.05). Environmental surveillance cultures recovered the organism repeatedly from the rectal probe handles of three electronic thermometers used exclusively on nonisolated patients in the intensive care unit. Restriction endonuclease analysis of plasmid DNA showed that all clinical and environmental isolates were identical. Infection control measures, including isolation of colonized or infected patients and removal of the rectal thermometer probes suspected to be responsible for transmission, resulted in termination of the outbreak. In-vitro, time-kill studies showed that the combination of ciprofloxacin, rifampin, and gentamicin resulted in bactericidal activity against the organism. CONCLUSIONS: This nosocomial outbreak of infection due to a highly vancomycin-resistant strain of Enterococcus is the first epidemic in which an electronic thermometer has been implicated as the vehicle of transmission for an infectious agent.

Adolescent↗
PubMed1992

Rainbow trout p53: cDNA cloning and biochemical characterization.

We have cloned and sequenced the p53-encoding cDNA of rainbow trout (Salmo gairdneri). The encoded product contains the characteristics found in all p53 proteins: (i) the five highly conserved domains, (ii) an acidic N terminus, (iii) a hydrophilic C terminus, and (iv) a penultimate serine residue. Furthermore, we demonstrate that the rainbow trout p53 is able to specifically interact with the SV40 large T antigen.

Amino Acid Sequence↗
PubMed1992

Bactericidal activity of ramoplanin against antibiotic-resistant enterococci.

Ramoplanin, a new lipoglycodepsipeptide antibiotic, was uniformly active against 65 strains of enterococci, including strains highly resistant to vancomycin, penicillin G, and gentamicin. MBCs were usually within a fourfold dilution of the MICs. In time-kill studies, ramoplanin alone demonstrated dose-dependent bactericidal activity against enterococcal strains that resisted killing by vancomycin or penicillin in combination with gentamicin.

Anti-Bacterial Agents↗
PubMed1992

p53 mutations in Raji cells: characterization and localization relative to other Burkitt's lymphomas.

The nuclear phosphoprotein p53 is an important regulator of cell proliferation in normal cells. Interestingly, the gene encoding p53 has usually undergone mutations in a wide range of tumor types. Recent studies of the p53 gene in Burkitt's lymphomas have demonstrated that mutations are extremely common, and in fact it is rare that both alleles of the p53 gene in these tumors are not inactivated by mutation or deletion. We present here genetic data regarding the status of the p53 gene in the Burkitt lymphoma cell line, Raji. As is typical for this type of tumor, both alleles have undergone point mutations. Further, statistical analysis of available data from a large number of Burkitt's lymphomas indicates an apparent tumor-specific distribution of p53 mutations. The possibility that specific mutations of the p53 gene may be important for different tumor types is discussed.

Alleles↗
PubMed1991

Immunological evidence for the association between simian virus 40 115-kDa super T antigen and hsp70 proteins in rat, monkey, and human cells.

Immunological evidence was provided that in subclone 7 cell line, which is derived from SV40 transformed cells, 115-kDa super T antigen, a transformation-competent, elongated form of large T antigen was physically complexed with hsp70 proteins. This conclusion was first based on the coimmunoprecipitation from unstressed or heat shocked subclone 7 cells of both super T antigen and hsp70 proteins. This was observed with any one of a set of anti-T monoclonal antibodies reacting to determinants located either in the C-terminal region or in the N terminal region. Reciprocally coimmunoprecipitation of both hsp70 and super T was also observed in the anti-hsp70 peptide serum-immunoprecipitate. The formation of complexes between hsp70 proteins and super T antigen in subclone 7 cells was also confirmed by Western blot experiments. Moreover, when expressed in cell lines originating from human (Hela cells) or monkey (CV1P cells) species following transfection with the relevant plasmid, super T antigen again displayed the ability to associate with hsp70 proteins. Considering that super T antigen was obtained in laboratory experiments as a stable evolutionary variant of SV40 large T antigen, it is suggested that the marked ability of super T antigen to associate with heat shock protein could be selectively advantageous under certain conditions.

Animals↗
PubMed1991

Endogenous HeLa p53 proteins are easily detected in HeLa cells transfected with mouse deletion mutant p53 gene.

It has been reported [Matlashewski et al. (1986). Eur. J. Biochem., 154, 665-672] that HeLa cells contain no detectable p53 protein, although they contain p53 mRNA which is translationally active. Here it is shown that endogenous HeLa p53 proteins were easily detected in HeLa cells transiently expressing mouse deletion mutant p53 gene after transfection with the appropriate recombinant plasmid. This detection was obtained by immunoprecipitation coupled with SDS-PAGE as well as by Western blotting experiments. Our results strongly suggest that HeLa p53 mRNA is actually translated in vivo, generating an extremely unstable p53 protein. Considering that the HeLa cell line is a HPV-18-positive human cervical carcinoma cell line, this high instability of HeLa p53 proteins is in keeping with the finding that E6 oncoprotein encoded by human papillomavirus 16 or 18 promotes the degradation of p53 proteins [Scheffner et al. (1990). Cell, 63, 1129-1136].

Animals↗
PubMed1990

Cefuroxime in total joint arthroplasty. Intravenous or in bone cement.

A prospective randomized clinical trial was performed in two centers to compare the effect of systemic cefuroxime and cefuroxime in bone cement in the prophylaxis of infection after total joint arthroplasty. In two comparable groups comprising 200 and 201 patients, there was no statistically significant difference in the incidence of superficial wound infection. The early deep infection rate was 1%, with no difference detected between the group that received antibiotic in bone cement and the group that received systemic antibiotic. There were no late deep infections. It is concluded that cefuroxime given systemically or in bone cement is an effective antibiotic in the prophylaxis of infection after total joint arthroplasty.

Aged↗
PubMed1990

Human breast cancer: identification of populations with a high risk of early relapse in relation to both oestrogen receptor status and c-erbB-2 overexpression.

We recently defined a new early prognostic factor, the ER+(R) status, which permits the discrimination of a group presenting a high risk of early relapse among the ER+ patients. This group was referred to as ER+(R2) in contrast to ER+(R1) which corresponded to the group of ER+ patients having a lower risk of early relapse. Taking into account the whole population including the ER- and inflammatory tumours, we have extended this view and showed that ER+(R) status is a significant predictor of disease-free survival. Determination of c-erbB-2 mRNA levels in the same series of tumours showed that high expression of c-erbB-2 mRNA is significantly correlated with ER-, inflammatory tumours and with lymph nodes involvement. Moreover, a multivariate analysis showed that c-erbB-2 mRNA overexpression was a significant predictor of early relapse (P = 0.02), as significant as ER negativity and ER+(R2). For ER+ patients a high level of c-erbB-2 mRNA constitutes a higher risk of relapse for both ER+(R1) and ER+(R2) patients. However, in the case of ER- patients, early relapses were strongly correlated with c-erbB-2 overexpression. The counterpart of this observation is that ER- patients with no overexpression of c-erbB-2 constitute a group with a relatively good prognosis.

Age Factors↗
PubMed1990

Analysis of immunoglobulin, T cell receptor and bcr rearrangements in human malignant lymphoma and Hodgkin's disease.

Rearrangements of immunoglobulin and T cell receptor (TCR) genes have been demonstrated in malignant lymphoid tumors of B and T cell origin. In Philadelphia chromosome-positive chronic myeloid leukemia and acute lymphocytic leukemia cells the bcr and c-abl genes are reorganized and transcripts composed of both genes are expressed. We analyzed the organization of bcr, immunoglobulin and TCR genes in malignant lymphomas. Our data show that in all B cell lymphomas analyzed the JH genes and in some cases also the J kappa genes were rearranged. In a Burkitt lymphoma and in a Kil lymphoma distinct rearranged TCR gamma fragments were detected, in a second Burkitt lymphoma two rearranged TCR beta gene fragments occurred together with a rearranged JH gene fragment. In two T cell lymphomas rearranged TCR beta genes were observed; one of these lymphomas also carried rearranged TCR gamma and JH genes. In Hodgkin's disease in 3 out of 7 cases rearranged immunoglobulin genes were detected. In 1 case, which was diagnosed as a follicular hyperplasia, rearranged JH and TCR gamma fragments appeared. In none of the analyzed lymphomas could bcr rearrangements be observed.

Gene Rearrangement↗
PubMed1989

Evolutionary conservation of the biochemical properties of p53: specific interaction of Xenopus laevis p53 with simian virus 40 large T antigen and mammalian heat shock proteins 70.

We have investigated the biochemical properties of Xenopus laevis p53. With an in vitro binding assay, we can detect a specific association between X. laevis p53 and simian virus 40 large T antigen. Furthermore, X. laevis p53 expressed in monkey COS cells is stably associated with this viral antigen. Like mammalian p53, X. laevis p53 in complex with simian virus 40 large T antigen exhibits a 20-fold increase of its half-life. On the other hand, X. laevis p53 is unable to associate either in vivo or in vitro with adenovirus type 5 E1B 55-kilodalton protein. We show by an immunological technique that X. laevis p53 forms specific complexes with mammalian hsp72 and hsp73 heat shock proteins only at a temperature well above the optimal growth temperature for X. laevis. Our results suggest that the protein-binding properties of p53 are closely related to the functional activity of the protein.

Animals↗
PubMed1989

Identification and characterization of a p53 gene mutation in a human osteosarcoma cell line.

The nuclear phosphoprotein p53 occurs at elevated levels in many transformed cells. Mutant forms of mouse p53 possess enhanced transforming activity compared with wild type p53. Mutant mouse p53 proteins form complexes with the 70 kDa family of heat shock proteins (HSPs). We previously demonstrated an association between p53 and the 70 kDa HSPs in the human osteosarcoma (HOS) derived cell line HOS-SL. We report here the molecular cloning and sequencing of the p53 gene from HOS-SL cells, and demonstrate that it is in fact mutant. Further, analysis of similar HOS-derived cell lines demonstrates that they also encode the same mutant form of p53, whereas the wild type form of p53 appears to be lost in these cells. Stability studies demonstrate an increased half life of the p53 protein in these cells, in keeping with its association with the HSP 70 proteins. A potential role for this p53 mutant in the transformation process is discussed.

Base Sequence↗
PubMed1988

The phosphoprotein p53 is down-regulated post-transcriptionally during embryogenesis in vertebrates.

The phosphoprotein p53 has been investigated mainly because of its relationship with tumorigenic transformation. In this communication, we report that, during the embryonal development of mouse and chicken, there is a decline in the steady-state levels of the p53 protein and an equal decline in p53 mRNA. During the development of the chicken, the relative rates of p53 transcription appear to be constant. p53 mRNA is relatively stable (half-life greater than 12 h) in both chicken and mouse embryos. We conclude that (i) the down-modulation of p53 mRNA (and of protein) during embryonal development has been well conserved during the evolution of the vertebrate, implying that the p53 protein may have a function in embryonal development; and (ii) the mechanism of control is apparently mainly on a post-transcriptional level.

Actins↗
PubMed1988

Intranuclear distribution of SV40 large T-antigen and transformation-related protein p53 in abortively infected cells.

The intranuclear localization of SV40 T-antigen (T-Ag) and the cellular protein p53 was studied in SV40 abortively infected baby mouse kidney cells using two complementary methods of ultrastructural immunocytochemistry in combination with preferential staining of nuclear RNP components and electron microscope autoradiography. Both proteins were revealed in association with peri- and interchromatin RNP fibrils containing the newly synthesized hnRNA. In addition, T-Ag and p53 remained bound, at least in part, to the residual internal nuclear matrix following nuclease and salt extractions of infected cells. The localization of T-Ag was different in SV40 lytically infected monkey kidney cells since, in addition to hnRNP fibrils, the viral protein was also associated with cellular chromatin. However, when lytic infection was performed in conditions of blocked viral DNA replication, T-Ag was no longer associated with the cellular chromatin but remained bound to the hnRNP fibrils. We conclude that the transforming and lytic functions of T-Ag can be distinguished by different subnuclear distributions. The significance of the association of T-Ag and p53 with hnRNP fibrils and the internal nuclear matrix is discussed in relation to the role of these structures in the control of cellular mRNA biogenesis.

Antibodies, Monoclonal↗
PubMed1988

Specific interaction between a subset of the p53 protein family and heat shock proteins hsp72/hsc73 in a human osteosarcoma cell line.

We report here immunological evidence for the specific association between p53 and hsp72/hsc73 heat shock proteins in a human cell line derived from an osteosarcoma. The same association between p53 and hsp72/hsc73 was observed in HOS-TE85 clone 5 from which the HOS-SL cell line was derived. This association was indicated by the co-immunoprecipitation from HOS-SL of both p53 and hsp72/hsc73 proteins observed with either an anti-p53 monoclonal antibody (PAb421) or an antiserum specifically reacting with hsp72/hsc73 heat shock proteins. Furthermore, Western blot analysis allowed us to show that hsp72/hsc73 proteins did not share an epitope with p53, confirming that the co-immunoprecipitation of p53 and hsp72/hsc73 was attributable to the physical association of the proteins. Data obtained from SDS-PAGE show that the HOS-SL cells expressed two forms of p53 with distinct molecular weights. Both forms contained several species with different isoelectric points ranging between pH 6.0 and 6.5. The data obtained from both 1D and 2D gel analyses consistently show that the p53 proteins involved in the association with hsp72/hsc73 were mainly the species that migrated with the slower mobility in the SDS dimension. The possibility is discussed that the HOS-SL p53 variant forming a complex with hsp72/hsc73 contains an activating mutation for transformation.

Antibodies, Monoclonal↗