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Biomedical subjects

E Adam

Publications and source records attributed to E Adam.

At least 55 records · Page 3Linked to original sources

Human papillomavirus testing as triage for atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesions: sensitivity, specificity, and cost-effectiveness.

OBJECTIVE: Our purpose was to evaluate the cost-effectiveness of the use of a Food and Drug Administration-approved human papillomavirus test in triaging patients with Papanicolaou smears showing atypical squamous cells of undetermined significance or a low-grade squamous intraepithelial lesion for colposcopy compared with an algorithm that used cytologic follow-up. STUDY DESIGN: Four hundred sixty-two women referred to our Colposcopy Clinic with a Papanicolaou smear report of atypical squamous cells of undetermined significance or a low-grade squamous intraepithelial lesion underwent repeat Papanicolaou smear, cervical colposcopy, directed cervical biopsy, and endocervical curettage. In addition, human papillomavirus testing by the Food and Drug Administration-approved HPV Profile (Digene Diagnostics, Silver Spring, Md.) test was done. A comparison of sensitivity, specificity, and cost-effectiveness of an algorithm determining the need for colposcopy on the basis of repeat cytologic testing versus an algorithm that incorporated repeat cytologic testing and human papillomavirus screening was done. The cost-effectiveness of both of these triage algorithms was also compared. RESULTS: As expected, high-risk human papillomavirus deoxyribonucleic acid was detected with greater frequency in relation to increasing severity of cervical intraepithelial neoplasia. In 268 women, the follow-up smear obtained in our clinic was reported as negative. High-risk human papillomavirus types were found in 23.5% of these women. In the human papillomavirus-negative women, 5.9% had grade 2 or 3 cervical intraepithelial neoplasia confirmed on cervical biopsy. In comparison, 20.6% of those with a positive result of the human papillomavirus test had grade 2 or 3 cervical intraepithelial neoplasia on biopsy (p < 0.001). Despite this difference, the sensitivity of a positive result of a high-risk human papillomavirus test in predicting the presence of grade 2 or 3 cervical intraepithelial neoplasia was only 52%. Among the women for whom a follow-up clinic Papanicolaou smear was reported as showing atypical squamous cells of undetermined significance or a low-grade squamous intraepithelial lesion, there was no difference in the frequency of biopsy-proved grade 2 or 3 cervical intraepithelial neoplasia between those women with a positive human papillomavirus test result and those with a negative test result. Colposcopy would have been recommended for 194 women because of a repeat clinic smear revealing atypical squamous cells of undetermined significance, a low-grade squamous intraepithelial lesion, or a high-grade squamous intraepithelial lesion, and in 21.6% of these grade 2 or 3 cervical intraepithelial neoplasia was shown on biopsy (sensitivity 63%, specificity 62%). Colposcopy would have been recommended for 180 women because high-risk human papillomavirus or a high-grade squamous intraepithelial lesion was detected at the clinic visit, and in 25% of this group grade 2 or 3 cervical intraepithelial neoplasia was shown on biopsy (sensitivity 67%, specificity 66%). Sensitivity and specificity were virtually identical for the two algorithms, but the cost of human papillomavirus testing was nearly double that of triage based on repeat cytologic testing alone ($692 vs $1246 per case). CONCLUSION: The Food and Drug Administration-approved HPV Profile test is not a cost-effective triage for patients referred with Papanicolaou smears reported as showing atypical squamous cells of undetermined significance or low-grade squamous lesions.

Algorithms↗

Relevance of human papillomavirus screening in management of cervical intraepithelial neoplasia.

OBJECTIVE: To evaluate the utility of human papillomavirus detection in identifying women with abnormal Papanicolaou smears who can be safely followed up with cytologic study only, we conducted a study to determine the sensitivity, specificity, and negative and positive predictive values of a Food and Drug Administration-approved human papillomavirus test kit for detection of cervical intraepithelial neoplasia in colposcopically directed biopsy specimens. STUDY DESIGN: We enrolled women with abnormal Papanicolaou smears referred to a colposcopy clinic serving indigent patients. All 1128 women had a referral Papanicolaou smear, a clinic Papanicolaou smear, and a sample for human papillomavirus deoxyribonucleic acid test; 1075 underwent colposcopically directed biopsies and endocervical curettage. We used the HPV Profile kit for human papillomavirus testing. RESULTS: Of 486 women with low-grade squamous intraepithelial lesions on Papanicolaou smear, 35.4% had high-risk human papillomavirus deoxyribonucleic acid detected, and of 592 with high-grade lesions, 44.4% had high-risk human papillomavirus detected. Among 527 women with biopsy specimens showing cervical intraepithelial neoplasia and in 267 with cervical intraepithelial neoplasia grades 2 or 3, 38.7% and 56.2% had high-risk human papillomavirus deoxyribonucleic acid detected. However, the sensitivity of human papillomavirus deoxyribonucleic acid detection to identify biopsy-confirmed cervical intraepithelial neoplasia grades 2 or 3 was 55.7%, and the positive predictive value of the test was only 34.9%. CONCLUSION: Human papillomavirus appears to be causally associated with cervical cancer but human papillomavirus screening does not appear to be of value to identify women with abnormal Papanicolaou smears who can be safely followed up with cytologic study alone.

Adolescent↗

Innervation of the thymus in normal and bone marrow reconstituted severe combined immunodeficient (SCID) mice.

The innervation of the thymus was studied in SCID mice: There was a relatively more dense innervation pattern in SCID mice as compared to normal BALB/c mice (from which SCID mice are derived), including nerve fibres immunoreactive for protein gene product 9.5 (PGP 9.5), tyrosine hydroxylase (TH), neuropeptide tyrosine (NPY) and vasoactive intestinal peptide (VIP), although there was no reactivity to substance P (SP) or leucine enkephalin (ENK). Only a few acetylcholinesterase (AChE)-positive nerve fibres were observed in the SCID thymus. Ten weeks after the transfer of bone marrow from normal BALB/c mice into SCID mice no immunoreactivity to the above markers was found, nor was there any AChE reaction, although histologically the thymus appeared normal and dot-blot assays demonstrated the presence of immunoglobulin indicating a return to normal bone marrow function in SCID mice. Both innervation and morphology were restored 6 months after bone marrow transfer. In conclusion, the thymus of SCID mice lacking thymocytes has visible neurotransmitter levels in the nerves, but after thymocyte repopulation by bone marrow transplantation the transmitters are generally not demonstrable. This indicates that the innervation may be more important for the establishment of the microenvironment rather than the maintenance of thymocyte differentiation.

Animals↗

Lectin histochemical HPA-binding pattern of human breast and colon cancers is associated with metastases formation in severe combined immunodeficient mice.

Metastasis formation is a major clinical problem in cancer treatment, and no significant progress in the treatment of metastatic spread has been made. This apparent lack of progress is partly caused by the absence of clinically relevant animal models of metastases. The binding of the lectin Helix pomatia agglutinin (HPA) has been associated with a poor prognosis in breast and colon cancer patients. HPA-positive and -negative human breast and colon cancer cell lines were transplanted into severe combined immunodeficient (SCID) mice. HPA-positive breast cancer cell lines (MCF-7 and T47D) metastasized in SCID mice, whereas the HPA-negative ones (BT20, HS578T and HBL100) did not. The HPA-positive colon cancer cell line HT29 metastasized, while the HPA-negative ones (COLO320DM, SW480 and SW620) did not. However, in two of eight SCID mice inoculated with the HPA-negative colon cancer cell line, CACO2 metastatic deposits were found. Despite this exception, HPA binding is a good indicator of the metastasis of human breast and colon cancer cells in SCID mice: 23 out of 26 HPA-positive cancers metastasized, as opposed to only two out of 38 HPA-negative cancers. This experimental model is well suited for investigating the functional role of carbohydrate residues recognized by HPA in breast and colon cancer metastasis.

Animals↗

The action of 5-fluorouracil on human HT29 colon cancer cells grown in SCID mice: mitosis, apoptosis and cell differentiation.

This study investigates the effects of the anti-metabolite 5-fluorouracil (5-FU) on the human colon cancer line HT29 (10(7) cells per dose) grown subcutaneously in severe combined immunodeficient (SCID) mice. The efficacy of 5-FU was quantitatively evaluated by comparing the tumour weight, mitotic and apoptotic tumour cell indices and the expression of the Ki-67 nuclear antigen in drug-treated animals and control animals. The tumour cell carbohydrates were assessed using a lectin panel. A significant reduction in the tumour weight was found 4 days after initial 5-FU treatment. 5-FU treatment reduced the percentages of mitoses but increased the apoptotic index in the tumour cells. In addition, 5-FU induced an increase in the signet ring cell population and an increased binding for lectins specific for N-acetylgalactosamine and galactose. However, the vast majority of signet ring cells were negative for Ki-67. The results of this study indicate that continuous treatment with 5-FU for 4 days targets metabolic processes relevant for both cell division and apoptosis. The relative increase in the signet ring population can be explained by the fact that the more proliferation-active stem cell population of the tumour is the primary target of the therapy. The lectin-binding patterns reflect these changes and are therefore differentiation linked.

Animals↗

Cytomegalovirus infection, lipoprotein(a), and hypercoagulability: an atherogenic link?

A link between cytomegalovirus (CMV) infection and atherosclerosis has been suggested by experimental, clinical, and epidemiologic studies. We investigated the association between CMV antibody titers in serum collected in 1974 in 300 adult residents in Washington County, Md, and hemostatic parameters in plasma collected in 1987 through 1989, when these individuals participated in the baseline examination of the Atherosclerosis Risk in Communities Study. The cross-sectional association of CMV serum antibodies and hemostatic parameters was also explored in another set of Atherosclerosis Risk in Communities cases and controls. In the longitudinal analyses, CMV titers in 1974 were directly associated with 1987 through 1989 plasma levels of von Willebrand factor, factor VIII, and protein C and negatively associated with activated partial thromboplastin time. In the cross-sectional analyses, CMV titers were directly related to antithrombin III and fibrinogen levels. When the association between CMV antibodies and atherosclerosis was examined in stratified analyses, a significant association was restricted to individuals with high levels of lipoprotein(a) and fibrinogen. These results are compatible with previous evidence suggesting that CMV virus might have procoagulant properties. The possible synergism of CMV infection and resulting hypercoagulability with reduced fibrinolysis due to increased lipoprotein(a) levels deserves further investigation.

Antibodies, Viral↗

Cytomegalovirus infection and atherosclerosis.

The biological properties of human cytomegalovirus are consistent with pathogenic involvement at several levels of the atherogenic process. Although the sites of latency of CMV have not been established, both smooth muscle cells and leukocytes are likely possibilities. The observations of viral antigens and nucleic acid sequences in arterial smooth muscle cells suggest that latent CMV infection of the arterial wall may be common in patients with atherosclerosis. The seroepidemiologic studies suggest that a periodically activated latent infection is present in patients with atherosclerosis. Important are the observations that in immunosuppressed heart transplant patients infected with CMV, atherosclerosis is prone to develop in the transplanted heart. This mainly circumstantial evidence of the involvement of CMV in human atherosclerosis provides an important basis for further investigation of the role of CMV in atherogenesis.

Animals↗

Immunophenotype of human HT29 colon cancer cell metastases in the lungs of scid mice: spontaneous versus artificial metastases.

The aim of this study was to compare the immunophenotype of the human colon cancer cell line HT29 tumour deposits in the lung which occurred spontaneously after subcutaneous implantation with those which arose after intravenous injection into severe combined immunodeficient (scid) mice. Irrespective of the route of implantation the colon cancer cells were readily observed in the lungs of the scid mice. Similar patterns of immunoreactivity for the proliferative markers (MiB-1, PCNA), and for the tumour suppressor gene (p53) were detected in both groups, and for carcinoembryonic antigen, with only minor quantitative differences in levels of marker expression. Whereas the marker CD44 variant 6 gave very little reaction after either route, cytokeratin expression varied amongst the different cytokeratins (CK 7, 18 or 20), and with the route of implantation. CA125 and E-cadherin were weakly expressed after intravenous injection, but generally not after subcutaneous implantation. Vimentin was not demonstrated in any of the specimens examined. In general, the expression of proliferative markers, and of oncogenes, appears to be independent of the implantation route, whilst expression of cell adhesion molecules can be dependent on the route of implantation.

Animals↗

Cohort study of cytomegalovirus infection as a risk factor for carotid intimal-medial thickening, a measure of subclinical atherosclerosis.

BACKGROUND: Animal studies as well as clinical and cross-sectional epidemiological studies in humans have suggested a possible role of cytomegalovirus (CMV) and other herpesvirus infections in the development of cardiovascular disease. METHODS AND RESULTS: The present report is based on a case-control study nested within a historical cohort. The case group comprised 150 individuals with elevated carotid intimal-medial thickness (IMT) measured by B-mode ultrasound at the first two examinations of the Atherosclerosis Risk in Communities (ARIC) Study (1987 through 1992). The control group comprised 150 age- and sex-matched individuals with low IMT. Antibody titers for CMV and herpesvirus 1 and 2 were determined in sera obtained in 1974 as part of a community-wide survey conducted in Washington County, Maryland. Case subjects had higher mean CMV antibody titers in 1974 sera than control subjects, although the difference was not statistically significant when adjusted for other cardiovascular risk factors. There was evidence of a graded relation between the odds of intimal-medial thickening and the levels of CMV antibodies that remained significant after adjustment for the main cardiovascular risk factors (P = .013). The adjusted odds ratio for a high CMV antibody titer (a positive/negative value > or = 20) compared with a positive/negative value < 4 was 5.3 (95% confidence interval, 1.5 to 18.0). CONCLUSIONS: The results from this first population-based cohort study of CMV infection and carotid IMT are compatible with the hypothesis of a causal role of CMV in atherosclerosis.

Antibodies, Viral↗

Histochemistry of therapeutically relevant enzymes in human tumours transplanted into severe combined immunodeficient (SCID) mice: nitric oxide synthase-associated diaphorase, beta-D-glucuronidase and non-specific alkaline phosphatase.

Human breast (MCF-7, HBL 100, T47D, BT20, HS578T), colon (HT29, CACO2, SW620, SW480, COLO320DM) and small cell lung cancer (NCI-N417, OH3, SW2) cell lines were transplanted subcutaneously into severe combined immunodeficient (SCID) mice. When sizeable tumours developed, the mice were sacrificed and the following enzyme activities were detected histochemically: presumed nitric oxide synthase-associated diaphorase (NOSaD), beta-D-glucuronidase (beta-Gluc) and non-specific alkaline phosphatase (alP). Except for HT29 and MCF-7 presumed NOSaD activity was not detected in the tumour itself or in the neo-vasculature of the tumours. beta-Gluc activity was found in all tumour cells (except N417 and COLO 320), in the necrotic parts of the tumours and in stromal cells of the tumour bed. AlP activity was present in all tumours including their necrotic areas. However, the activities of beta-Gluc and alP varied considerably even within one tumour, ranging from very weak to very strong. Principally the results show that the human/SCID mouse tumour model is well suited to test modern applications of tumour therapy involving the enzymes NOSaD, beta-Gluc and alP. In particular, antibody directed enzyme prodrug therapy concepts and activation of prodrugs by enzymes released from tumour cells into the necrotic areas of the tumour can be evaluated in this in vivo model.

Alkaline Phosphatase↗

Transplantation of a human ovarian cystadenocarcinoma into severe combined immunodeficient (SCID) mice--formation of metastases without significant alteration of the tumour cell phenotype.

Human ovarian papillary cystadenocarcinoma cells were injected intraperitoneally into severe combined immunodeficient (SCID) mice. After intraperitoneal application the cells, designated SoTü, grew well in vivo, lodged on to the peritoneum, formed local metastatic deposits, led to the development of ascites in the mice and formed distant metastases in the lungs. If lodged in the ovary, the morphology of the SoTü tumour remarkably resembled that of the primary tumour in the patient. In contrast, several attempts failed to maintain the SoTü cells in vitro. If SCID mouse ascites derived SoTü were transplanted subcutaneously in SCID mice, they formed cystic tumours which also metastasized into the lungs. Immunophenotypical analysis of cell adhesion molecule expression, cell proliferation markers, various oncoproteins, keratin, vimentin, and lectin binding site expression all showed striking similarity between the primary tumour and the SCID mouse explants. In particular, expression of binding sites for the lectin Helix pomatia agglutinin (HPA), which has been shown to be an index of metastatic potential in several human carcinomas, was found on the primary tumour as well as on tumour cells grown in SCID mice, indicating that HPA might be a prognostic indicator in ovarian carcinoma as well. Our results demonstrate that the human/SCID mouse system can mimic growth and distant metastasis formation of human ovarian carcinoma. Although the formation of distant metastases is a relatively rare event in patients, this model system might help to elucidate mechanisms of metastasis formation in ovarian cancer.

Animals↗

The CREB, ATF-1, and ATF-2 transcription factors from bovine leukemia virus-infected B lymphocytes activate viral expression.

Efficient transcription and replication of the bovine leukemia virus (BLV) genome require both the viral long terminal repeat (LTR) and the virus-coded transcriptional activator Tax, which functions through a 21-bp sequence (Tax-responsive element [TxRE]) which is repeated three times within the LTR. Since Tax does not bind directly to DNA, host cell transcription factors play a central role in BLV expression. Electrophoretic mobility shift assays with nuclear extracts prepared with infected bovine B lymphocytes revealed five TxRE-specific complexes (C1, C2, C3, C4, and C5). Here, by using a UV-induced indirect labeling technique (UV cross-linking) in conjunction with mobility shift assays, eight major polypeptides of 31, 33, 42, 46, 51, 57, 87, and 119 kDa were identified within these five complexes. Immunoprecipitation experiments identified the 57- and 119-kDa proteins as cyclic AMP response element-binding (CREB) proteins, the 46- and 51-kDa proteins as activating transcription factor-1 (ATF-1), and the 87-kDa as protein ATF-2. All of these proteins (except the ATF-1 protein of 51 kDa) belong to the complex C1, which is the major complex identified in freshly isolated BLV-infected lymphocytes from cattle with persistent lymphocytosis. In transient-cotransfection experiments, these three transcription factors were able to activate LTR-directed gene expression in the presence of protein kinase A or Ca2+/calmodulin-dependent protein kinase IV. CREB protein, ATF-1, and ATF-2 thus appear to be the major transcription factors involved in the early stages of viral expression.

Activating Transcription Factor 1↗

Cellular pathways involved in the ex vivo expression of bovine leukemia virus.

Bovine leukemia virus (BLV) is the etiologic agent of enzootic bovine leukosis. The virus adopts a strategy based on the lack of viral expression in vivo; only very rare BLV-infected B lymphocytes express viral information. When the cells are isolated from animals in persistent lymphocytosis and cultivated ex vivo, a tremendous increase in viral expression occurs. To gain insight into this mechanism, we employed a general approach using chemicals that interfere specifically with cellular pathways involved in signal transduction from the cell membrane to the nucleus. Our data demonstrate that BLV expression is not correlated with the activity of protein kinase A (PKA) and is even inhibited by cyclic AMP (cAMP). The cAMP/PKA pathway is thus apparently not involved in ex vivo viral expression. In contrast, PKC appears to play a key role in this process. Phorbol myristate acetate can directly activate viral expression in B cells (in the absence of T cells). Furthermore, calphostin C, a highly specific inhibitor of PKC, partly decreases ex vivo BLV expression. Our data further demonstrate that calmodulin and calcineurin, a calmodulin-dependent phosphatase, play a key role in the induction of viral expression. The involvement of this calmodulin-dependent pathway could explain the induction of expression that cannot be assigned to PKC. Furthermore, it appears that the activation of viral expression requires a calmodulin but not a PKA-dependent pathway. These data highlight major differences between transient transfection and ex vivo experiments. Finally, despite their homologies, BLV and human T-cell leukemia virus appear to use different signal transduction pathways to induce viral expression.

Animals↗

Cytomegalovirus and atherosclerosis.

The investigations reviewed in this paper provide evidence that a member of the herpesvirus family can cause atherosclerosis in chickens. In vitro experiments, as well as studies of arteries from infected birds, suggest that a virus-induced alteration of cellular metabolism, which results in the accumulation of cholesterol and cholesteryl esters, may be the primary mechanism in development of viral atherosclerosis. In addition, the fact that the same avian virus induces a malignant lymphoma suggests that it may also have the potential to stimulate the proliferation of other cells, notably arterial smooth muscle cells. The evidence for involvement of one or more members of the herpesvirus family in human atherosclerosis is much more circumstantial. Cytomegalovirus (CMV) is prevalent, increasing with age, so that a majority of the human population becomes infected by adulthood. As with other herpesviruses, the infection with CMV is usually subclinical or latent. Although the sites of latency for CMV have not been established, both smooth muscle and leukocytes are likely possibilities. The observations of viral antigens and nucleic sequences, but not infectious virus, in arterial smooth muscle cells suggests that latent CMV infection of the arterial wall may be common in patients with atherosclerosis.

Adolescent↗

Cytomegalovirus and atherosclerosis.

Finding that an avian herpesvirus can cause atherosclerosis in chickens prompted studies of human herpesviruses in human atherosclerosis. Antigens and nucleic acid sequences of cytomegalovirus (CMV), a widespread member of the herpesvirus family, were found in arterial lesions in human atherosclerosis, but infectious virus has not been observed. In atherosclerosis patients, high levels of CMV antibodies are present, suggesting the presence of virus that had been activated from a latent state. Atherosclerosis also develops in immune-suppressed heart transplant patients infected with CMV. The properties of CMV are consistent with its involvement at several levels of the atherogenic process. If this concept is correct, immunization with a CMV vaccine should prevent CMV infection and atherosclerosis.

Arteriosclerosis↗

Transcription of tobacco phytochrome-A genes initiates at multiple start sites and requires multiple cis-acting regulatory elements.

Promoter regions of the Nicotiana tabacum PHYA1 and PHYA2 genes display 89% sequence identity. Analysis of the 5' ends of both the PHYA1 and the PHYA2 transcript revealed multiple, distinct mRNA species, each differing in length and in abundance. The levels of the major PHYA1, PHYA2 transcripts were found to be auto-regulated by phytochrome. This auto-regulation was most efficient in 2-8-day old seedlings. Furthermore, we examined the expression pattern of the PHYA1-GUS reporter gene, containing a 4700 bp PHYA1 promoter fragment or its 5'-deletion derivatives, by GUS histochemistry and by RNase protection assays in transgenic tobacco plants. Our data indicate that the PHYA1 promoter contains three regions which are necessary for the maximum level and regulated expression. We show that a 264 bp promoter fragment contains a cis-regulatory element(s) responsible for expression in the root tips of transgenic seedlings. The major cis-regulatory elements required for high-level transcription and expression in other organs are located in separate regions of the PHYA1 promoter. These data indicate the contribution of multiple cis-regulatory elements for the maximum and regulated expression of tobacco genes coding for phytochrome A protein.

Base Sequence↗

Molecular characterization and expression of a tobacco histone H1 cDNA.

We have isolated a 1104 bp tobacco cDNA clone (H1c12) which includes an 846 bp open reading frame. This encodes a polypeptide of 282 amino acid residues and represents the largest plant H1 histone identified so far. The structure of the deduced protein shows the classical tripartite organization of the H1-type linker histones. The expression of the tobacco H1 histone gene(s) corresponding to the H1c12 cDNA clone was examined during different developmental stages. We found that, at the level of steady-state mRNA, expression of gene(s) encoding this H1 histone was rapidly induced in germinating seeds. The H1 gene was expressed in all tissues examined. However, its expression was higher in tissues known to contain meristematic cells. Furthermore, in the leaves of mature plants accumulation of the H1 mRNA exhibits a very characteristic oscillation. This latter finding indicates that, at least in fully developed plants, the expression of this type of H1 histone gene(s) is modulated by a diurnal cycle.

Amino Acid Sequence↗

Biochemical, histochemical and cell biological investigations on the actions of mistletoe lectins I, II and III with human breast cancer cell lines.

Cytotoxicity of the mistletoe lectins I, II and III towards six human breast cancer cell lines was assessed using the Mossman assay. In addition, binding of the three mistletoe lectins to the separated membrane glycoproteins of these cell lines, the binding and uptake of these lectins into the cells in tissue culture and the binding of the lectins to histological preparations of these cell lines were analysed. The results indicate that there are quantitative differences concerning the toxicity of these three lectins towards the different cell lines. Furthermore, the lectin binding pattern in the cell lines differed. In Western blots, several membrane glycoproteins were labelled by the lectins. Our results indicate subtle differences between the three lectins with regard to the parameters mentioned above; however, the toxicity of all three lectins from mistletoe is so similar that they all seem suitable for the construction of immunotoxins.

Breast Neoplasms↗