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Biomedical subjects

D Moritz

Publications and source records attributed to D Moritz.

17 recordsLinked to original sources
PubMed1997

Risk factors for hip fracture in men. Hip Fracture Study Group.

To identify risk factors for hip fracture in men, the authors conducted a case-control study involving 20 hospitals in Philadelphia, Pennsylvania, and 14 hospitals in Kaiser Permanente Medical Care Program of northern California. The 356 enrolled men had been admitted with a radiologically confirmed first hip fracture. The 402 control men either were from the Philadelphia area or were members of Kaiser Permanente and were frequency matched to the cases by age and ZIP code or telephone exchange. Information on potential risk factors was obtained through personal interviews. Men in the lowest quintile of body mass had a greatly increased risk of hip fracture compared with men in the heaviest quintile (odds ratio (OR) 3.8, 95% confidence interval (CI) 2.3-6.4). Premorbid lower limb dysfunction was associated with increased risks for hip fracture (OR 3.4, 95% CI 2.1-5.4). Increased risks were also observed with the use of cimetidine (OR 2.5, 95% CI 1.4-4.6) and psychotropic drugs (OR 2.2, 95% CI 1.4-3.3). Smoking cigarettes or a pipe increased the risk of hip fracture, and this association was independent of body mass. Finally, previous physical activity was markedly protective. Factors thought to affect bone density as well as factors identified as risk factors for falls appear to be important determinants of the risk of hip fracture in men. Physical activity may be a particularly promising preventive measure for men. Additional studies of the use of cimetidine on osteoporosis and osteoporotic fractures are indicated.

Activities of Daily Living↗
PubMed1997

Specific cytotoxic T lymphocytes in gene therapy.

Cytotoxic T lymphocytes possess the capacity to lyse target cells which express antigens on their surface recognized by the T cell receptor. These cells are crucial in the body's defense against foreign antigens. It has long been a goal of tumor biology to utilize T cells specialized in the elimination of unwanted cells for the treatment of cancer. The killing activity of T lymphocytes is restricted to specific antigen-presenting cells. For this reason the use of cytotoxic T cells in the elimination of cancer cells is limited to cancer cells which present neoantigens on their surface. To circumvent this limitation we describe a procedure in which the zeta component of the T cell receptor is genetically manipulated and equipped with an extracellular recognition domain. Introduction of a chimeric gene, consisting of the zeta chain of the T cell receptor and a single-chain antibody domain, into cytotoxic T lymphocytes results in T cells with a predetermined recognition specificity for particular tumor cells. The MHC restriction of target cell recognition can be avoided and tumor cells recognized by the single chain antibody domain can be recognized and lysed. Retroviral-mediated gene transduction was used to introduce chimeric zeta chain constructs into primary T cells of mice. The cocultivation of retrovirus producing helper cells with in vitro activated T lymphocytes led to a high gene transduction efficiency into primary T cells. These primary T cells assumed a predetermined specificity for target cell recognition and lysis. The production and provision of tumor cell specific T lymphocytes might not be sufficient to eradicate large tumors in vivo. Using a Schwannoma cell line, we showed that transplanted tumors secrete transforming growth factor beta and thereby stifle the action of lymphocytes. We suggest that a coordinated strategy including the suppression of tumor cells specific antilymphocyte action and the provision of tumor cell specific T cells might be required to successfully eliminate tumor cells in vivo.

Animals↗
PubMed1996

Growth retardation of tumors by adoptive transfer of cytotoxic T lymphocytes reprogrammed by CD44v6-specific scFv:zeta-chimera.

Variants of the CD44 protein family containing sequences encoded by variant exon 6 (v6) are involved in the metastatic spread of rat and human tumors. The rat-specific antibody 1.1ASML, which recognizes a v6 epitope, interferes with metastatic dissemination of a rat pancreatic carcinoma. The single-chain antigen-binding fragment of this monoclonal antibody was fused to the zeta-chain of the T-cell receptor complex. The appropriate fusion gene was incorporated into a retroviral gene transfer vector. Murine cytotoxic T lymphocytes (CTLs) were infected, and cellular clones which express the single-chain zeta-chain fusion protein on their cell surface were selected. These CTLs are not MHC-restricted in their CD44v6 recognition and exhibit in vitro lytic activity toward cells expressing CD44 variants comprising exon v6. Tumor cell xenografts grown in athymic nude mice are suppressed in their growth upon infusion of the genetically manipulated CTLs. Our data indicate that the CD44v6 epitope is an effective target for immune tumor therapy and demonstrate the efficacy of genetically engineered CTLs in targeting tumors expressing such epitopes.

Adoptive Transfer↗
PubMed1996

Expression of chimeric envelope proteins in helper cell lines and integration into Moloney murine leukemia virus particles.

New retroviral constructs with a grafted specificity of infection could become useful gene delivery vehicles with applications in systemic gene therapy. We have constructed retroviral vectors to target gene transfer to human tumor cells. Chimeric envelope proteins have been expressed to obtain viral particles with a defined specificity of infection. Two tumor cell-specific recognition domains were cloned and fused with the viral envelope gene. A recognition domain specific for ErbB-2 expressing tumor cells was derived from a monoclonal antibody directed against the ErbB-2 receptor in the form of a single chain antibody domain (scFv-erbB-2). The receptor binding domain was derived from the heregulin gene (HRG70). This domain provides recognition specificity for ErbB-3 and ErbB-4 receptor expressing tumor cells. The recognition domains were inserted at the amino terminal end into the MoMLV envelope gene. Helper cell lines were established which express the recombinant envelope protein genes, the gag and pol genes and packageable retroviral RNA. The analysis of the helper cell line revealed that the recombinant ErbB-2 scFv-envelope protein was expressed, but not incorporated into viral particles. The scFv-erbB-2 envelope protein was not inserted into the cell membrane and the assembly of retroviral particles was not completed. In contrast, the HRG70-envelope protein was expressed on the surface of the helper cells and incorporated into retroviral particles. The HRG70-envelope protein, however, did not alter the host range of infection. Only cells expressing the ecotropic viral receptor could be infected.

3T3 Cells↗
PubMed1996

Cytolysis of tumor cells expressing the Neu/erbB-2, erbB-3, and erbB-4 receptors by genetically targeted naive T lymphocytes.

We are developing strategies to use naive T lymphocytes in cancer therapy. For this purpose, we are deriving T cells with specificity of recognition for defined tumor cells. To direct effector lymphocytes toward tumor cells, we have manipulated the recognition specificity of naive rat and mouse T lymphocytes and a mouse T-cell line. The cells were stably transduced with a chimeric T-cell receptor (TCR) component. The zeta chain of the TCR consists of a single transmembrane protein with a short extracellular domain and an intracellular domain for TCR signaling. We provided an extracellular tumor cell recognition domain to the zeta chain. Human heregulin beta1 (ligand to the erbB-3 and erbB-4 receptors) and three different single-chain antibodies specific for the human and rat Neu/erbB-2 receptors were used. One single-chain antibody (C11) is directed against the rat Neu protein, and one single-chain antibody (FRP5) is directed against the human erbB-2 receptor. The single-chain antibody (R-AK) directed against the Mr 14,000 fusion protein of orthopox viruses served as a control. An efficient procedure was devised to introduce the chimeric genes into primary rat and mouse T lymphocytes. Retrovirus-producing packaging cell lines were cocultured with the T cells activated by phytohemagglutinin and interleukin 2. T-cell lines were transduced by exposure to retrovirus-containing supernatants from helper cell lines. Expression of the fusion genes was determined by fluorescence-activated cell sorting analysis. More than 80% of the naive rat and mouse T cells and 85-100% of the cells from the established T-cell lines expressed the fusion genes within 48 h after infection. The expression of the fusion genes was maintained for at least 10 days after infection. Target cells expressing Neu/erbB-2, erbB-3, or erbB-4 were lysed in vitro with high specificity by T cells expressing the corresponding recognition proteins. No selection of a marker gene is necessary to confer a predetermined recognition specificity. The described experiments are important for a gene therapy approach to cancer treatment with autologous T cells.

3T3 Cells↗
PubMed1995

Biotechnological and gene therapeutic strategies in cancer treatment.

New anti-cancer agents are being developed which incorporate cancer-cell-specific recognition functions and are thus able to distinguish between normal and tumor cells. Recognition is dependent on the enhanced expression of antigenic determinants on the surface of tumor cells. The ErbB-2 receptor (ErbB-2R) is overproduced in a high percentage of adenocarcinomas arising in the breast, ovary, lung and stomach, when compared to normal cells. The tumor-enriched expression and extracellular accessibility make this receptor a suitable target for directed tumor therapy. A gene expressing the single-chain antibody molecule (scFv), specific for the extracellular domain of the ErbB-2R, was constructed by joining cDNAs encoding the light- and heavy-chain variable domains of the monoclonal antibody (mAb) FRP5. This scFv-encoding gene has been used as a targeting domain for two effectors: (i) A recombinant immunotoxin-encoding gene was constructed by adding sequences encoding a modified Pseudomonas aeroginosa exotoxin A (ETA) to the scFv-encoding DNA. (ii) Cytotoxic T-lymphocytes (CTL) with specificity for ErbB-2R-producing tumor cells were generated by retroviral transfer of a chimeric gene which encodes the scFv(FRP5), a hinge region and the zeta-chain of the T-cell receptor (TCR) complex. The bacterially produced recombinant immunotoxin scFv(FRP5)-ETA binds specifically to the ErbB-2R and displays both in vitro and in vivo cytotoxic effects selective for tumor cells producing high levels of the ErbB-2R. Target cells expressing the ErbB-2R gene were lysed in vitro with high specificity by the scFv::hinge::zeta-expressing T-cells.(ABSTRACT TRUNCATED AT 250 WORDS)

3T3 Cells↗
PubMed1995

Prolactin and interleukin-2 receptors in T lymphocytes signal through a MGF-STAT5-like transcription factor.

The cell surface receptors for PRL and interleukin-2 (IL-2) are structurally distinct, but share regulatory tasks in T lymphocytes. They can stimulate proliferation and activate transcription of over-lapping sets of genes of T cells. PRL and IL-2 receptor activation are both linked to the Jak/Stat (signal transducer and activator of transcription) pathway. We investigated the ability of PRL and IL-2 to activate Stat proteins in different T cell lines. The DNA binding specificities, the reactivities toward Stat-specific antisera, and the mol wt of IL-2- and PRL-induced DNA-binding proteins in Nb2 and C196 T cell lines were investigated. A comparison with the Stat proteins induced by interferon-gamma, PRL, and IL-6 in T47D mammary tumor cells was made. We found that these parameters were indistinguishable for one of the PRL- and IL-2-induced factors. A transcription factor closely related to mammary gland factor-Stat5 is rapidly activated upon interaction of IL-2 and PRL with their respective receptors. Activation of a second protein related to Stat1 was also observed. Our results emphasize the role of PRL as a regulator of the immune response and indicate that the Stat factors mammary gland factor-Stat5 and Stat1 play a role in the regulation of gene expression during T cell development.

Animals↗
PubMed1995

A spacer region between the single chain antibody- and the CD3 zeta-chain domain of chimeric T cell receptor components is required for efficient ligand binding and signaling activity.

The elimination of tumor cells by cytotoxic T lymphocytes (CTLs) could become the basis of a biological cancer therapy. The recognition specificity of cytotoxic T lymphocytes (CTLs) can be genetically modified by stable introduction of chimeric T cell receptor genes and thus be directed towards tumor cells. We designed a recombinant T cell receptor (TCR) component consisting of a single chain Fv derivative of a monoclonal antibody (scFv) serving as the extracellular antigen-binding domain and the zeta-chain of the TCR/CD3 complex serving as a signal transducing domain. Three chimeric receptor constructs differing in their molecular structure were derived and their functions in transduced T cells compared. A construct in which the scFv domain, specific for the ErbB-2 receptor, was fused directly to the zeta-chain, and two constructs containing different hinge regions between the functional domains, were made. The hinge regions serve as spacers which increase the distance of the scFv moiety from the plasma membrane. Only the two scFv-zeta chimeras containing a hinge region showed ErbB-2 binding activity, when expressed in T cells. The scFv-zeta construct which lacks a spacer segment did not. Consistently, only the spacer-containing chimeras transduced T cell receptor signals following ErbB-2 mediated crosslinking. An increase in intracellular Ca2+ concentrations and cytokine secretion was observed. ErbB-2 expressing tumor cells were efficiently lysed by CTLs which expressed the spacer-containing scFv-zeta chimeras. Our results will help to optimize the design of recombinant T cell receptor components useful in the grafting of a specificity of recognition on to cytotoxic T cells and possibly the gene therapy of cancer.

3T3 Cells↗
PubMed1994

Cytotoxic T lymphocytes with a grafted recognition specificity for ERBB2-expressing tumor cells.

Experimental approaches which exploit the targeted cytolytic activity of lymphocytes are being developed for cancer therapy. We generated cytotoxic T lymphocytes (CTLs) with specificity for ERBB2 receptor-expressing tumor cells. A binding function was conferred directly on the zeta chain of the T-cell receptor (TCR) complex to circumvent major histocompatibility complex-restricted antigen recognition through the alpha and beta chains of the TCR. A chimeric gene was constructed which encoded a single-chain Fv antibody (scFv, consisting of the joined heavy- and light-chain variable domains of a monoclonal antibody against the extracellular domain of the ERBB2 receptor), a hinge region as a spacer, and the zeta chain of the TCR. This gene was introduced into CTLs by retroviral gene transfer. The signaling potential of the scFv/hinge/zeta receptors was demonstrated by secretion of interferon gamma upon coincubation with ERBB2-expressing cells. Target cells expressing the ERBB2 gene were lysed in vitro with high specificity by the scFv/hinge/zeta-expressing T cells. The growth of ERBB2-transformed cells in athymic nude mice was retarded by adoptively transferred scFv/hinge/zeta-expressing CTLs. Transduced CTLs labeled with a fluorescent dye were specifically detected in tumor sections. Our results suggest that tumor cell lysis by CTLs grafted in vitro with a major histocompatibility complex-independent recognition could become a gene-therapy approach to cancer treatment.

3T3 Cells↗
PubMed1993

The shortened advanced course for Army physicians.

The Army uses a series of career courses to prepare officers for progressive assignments. These courses have not been widely utilized by Army physicians. To improve the military education of physicians, an abbreviated Advanced Course was developed by the Academy of Health Science. A study of this course by the physicians attending its first offering showed that 8 weeks was an appropriate length. Information is provided to help improve the course and encourage attendance by Army physicians. This course will likely become mandatory and will be a key element in the training of all Army physicians.

Curriculum↗
PubMed1992

Nursing diagnoses in an oncology population.

The purposes of this study are to identify the nursing diagnoses occurring in an oncology population, to validate these using the clinical validation model, and to determine whether clusters of defining characteristics and etiologies occurred among the diagnoses identified. Secondary analysis was conducted using the patient care records of 48 oncology patients. Twenty-five nursing diagnoses were identified. The most common diagnoses were alteration in comfort (pain) and alteration in nutrition (less than body requirements). The etiologies of stress, pain, life changes, disease, and treatment occurred in some combination in 14 diagnoses. The defining characteristics of pain and fatigue/weakness occurred in over six diagnoses. Clusters of defining characteristics occurred with eight diagnoses. Clusters of etiologies occurred with the diagnosis of sleep/rest disturbance. Validation of defining characteristics and etiologies indicated variation from those proposed by the North American Nursing Diagnosis Association. One overriding variation was in the degree of specificity of defining characteristics used in clinical practice. The findings of this study support the need for continued validation of nursing diagnoses and continued education of nurses in the use of nursing diagnoses. The findings also contribute to the body of knowledge in nursing diagnoses in oncology patients, and contribute to the work beginning to be done in the field of nursing diagnosis with research into the existence of clusters of defining characteristics, etiologies, and/or nursing diagnoses.

Adult↗
PubMed1990

CD4-affinity purification of recombinant and native HIV gp120 and comparison of the affinity constants for the receptor.

Soluble CD4-immunoglobulin chimeric proteins were covalently attached to CNBr-activated Sepharose. This affinity matrix was used to establish a powerful new method to isolate different species of the HIV external glycoprotein gp120 from cell-free culture supernatants. Recombinant gp120 was expressed in Baculovirus-infected insect cells and isolated from cell-free culture supernatants. The recombinant protein has an apparent molecular mass of 130 kDa. These two gp120 species were shown to be of identical molecular size after complete deglycosylation achieved by endoglycosidase treatment, and they bound to CD4-H gamma l with the same binding constant, that was reported for native forms of gp120 and CD4. Thus the different glycosylation of gp120 does not influence its affinity to CD4 and the gp120-CD4 complex can be reversibly dissociated.

Blotting, Western↗
PubMed1990

Mutation of conserved N-glycosylation sites around the CD4-binding site of human immunodeficiency virus type 1 GP120 affects viral infectivity.

Infection by the human immunodeficiency virus type 1 (HIV-1) is initiated through interaction of its exterior envelope glycoprotein gp120 with the CD4 receptor on target cells. To address the possible role of N-glycosylation of HIV-1 gp120 in binding CD4, we mutated different conserved N-glycosylation site Asn-residues in the vicinity of the putative CD4 binding site, as single mutations or in combinations. Authentic and mutant gp120 proteins were produced using the baculovirus expression system. All mutant proteins were produced and secreted at similar levels and could be immunoprecipitated with an HIV(+)-serum. Furthermore, all glycosylation mutants retained the full capacity to bind CD4 except for a triple mutant which showed reduced binding. Different gp120 mutant genes were then introduced in an infectious proviral DNA clone. Upon transfection of MT-2 cells, the authentic HIV-1 clone induced maximal virus production after 6 days. In the case of the triple glycosylation mutant, comparable virus production was first reached after a delay of about 12 days. Moreover, in contrast to native HIV, the mutant virus induced no typical multinucleated giant cells. These results suggest that the attached carbohydrates around the CD4-binding site of gp120, may contribute to the generation of this protein domain required for high affinity receptor interaction.

Acquired Immunodeficiency Syndrome↗
PubMed1981

Long-term toluene abuse.

The authors briefly review the literature on the use of toluene as an intoxicating agent. They describe two cases in which the habit of sniffing toluene vapors extended over many years, discuss the rarity of this condition, and speculate about the conditions that might account for both the rarity and the occurrence of long-term toluene abuse.

Adolescent↗