Biomedical subjects

J E Brennan

Publications and source records attributed to J E Brennan.

5 recordsLinked to original sources

PubMed1988

Considerations in the use of laboratory robots: aspects of safety and accuracy.

A general-purpose laboratory robot was configured to prepare blood samples for the HBsAg and anti-HIV tests. Several issues were studied in order to eliminate problems and optimize the system. These included pipetting accuracy, intersample carryover, reagent interference, splashing and aerosol generation and user-related issues. A number of general guidelines were developed to assist others in developing and implementing systems for this and similar applications.

Evaluation Studies as Topic↗

PubMed1986

Antibodies to the N-terminal portion of cartilage-inducing factor A and transforming growth factor beta. Immunohistochemical localization and association with differentiating cells.

Two apparently homologous proteins, designated CIF-A and CIF-B, were previously isolated from bovine bone on the basis of their cartilage-inducing activity in culture. CIF-A has been shown to probably be identical to transforming growth factor beta (TGF-beta). To address the question of tissue localization, antibodies to CIF-A were produced using a synthetic polypeptide identical to N-terminal residues 1-30. The antibodies were immunoreactive with bovine CIF-A and human TGF-beta, did not recognize CIF-B, and did not recognize other molecular weight species in crude bovine bone extracts. The antibodies were used to immunohistochemically localize CIF-A/TGF-beta in fetal bovine bone and other tissues. There was abundant staining of osteocytes throughout cancellous and cortical bone as well as chondrocytes within the articular cartilage, although growth plate-associated chondrocytes were not labeled. In addition, immunoreactive cells were detected in bone marrow (megakaryocytes and some mononuclear cells), fetal liver (hematopoietic stems cells), and the thymus (Hassall's corpuscle and some medullary thymocytes). In the kidney, the antibodies labeled a population of epithelial cells lining the calyces. Tissues which did not have detectable amounts of CIF-A/TGF-beta included the thyroid, adrenal, salivary gland, and aorta. Results presented here suggest that the factor may function in vivo as a general development and repair factor and may play a significant role in the differentiation of many cell types including chondrocytes, osteocytes, T-lymphocytes, and red blood cells.

Amino Acid Sequence↗

PubMed1986

The human immune response to reconstituted bovine collagen.

The human immune response to bovine dermal collagen was characterized through histologic, serologic, and immunoblotting methods. Collagen-sensitive patients were identified by hypersensitivity to intradermal exposure to ZYDERM Collagen Implant--a pepsin-solubilized, reconstituted, bovine dermal collagen. Biopsies of test sites in the forearm were obtained from several collagen-sensitive patients. Histologic examination revealed an implant-associated palisading foreign body granuloma. The lesion also contained a mixed cell infiltrate of histiocytes, lymphocytes, and eosinophils. Sera were collected from patients who developed erythema or induration at intradermal test or treatment sites, and were evaluated for antibodies to bovine dermal collagen by an enzyme-linked immunosorbent assay (ELISA). Sera with anti-collagen antibodies were further characterized in this study. The circulating antibodies were reactive with both native and heat-denatured bovine dermal collagen. By using purified alpha 1(I) and alpha 2(I) polypeptides, these sera were found to have antibodies reactive with both alpha-chains. Each alpha-chain was fragmented by using cyanogen bromide (CB). The CB peptides were electrophoretically separated, and these sera were evaluated for antibodies to the major fragments by using an immunoblotting technique. Of the sera evaluated by this method, 89% (23/26) had antibodies to alpha 1-CB6; 77% (20/26) had antibodies to alpha 2-CB4; and 65% (17/26) had antibodies reactive with both CB fragments. In addition, most sera (77%) contained antibodies reactive with two or more (up to five) of the major CB peptides. The least antigenic fragment was alpha 2-CB3,5 (8%). In addition, these sera had antibody activity against both native and heat-denaturated bovine types III and II collagens. Little or no interspecies (rat or guinea pig) cross-reactivity (types I and II) was detected. Furthermore, these sera did not have antibodies against human types I, II, and III collagens.

Animals↗

PubMed1986

Differentiation of rat mesenchymal cells by cartilage-inducing factor. Enhanced phenotypic expression by dihydrocytochalasin B.

The role of cell shape in chondrogenesis was studied by using rat mesenchymal cells cultured with cartilage-inducing factor (CIF). Here we report that enhanced expression of chondroblastic markers by induced cells was attained by culturing cells in monolayer in the presence of dihydrocytochalasin B (DHCB). This effect was optimal at 3 microM DHCB and was apparent after 3 days in culture. Mesenchymal cells cultured with DHCB alone exhibited no detectable increase in cartilage proteoglycan synthesis, whereas cells cultured with 3 microM DHCB and 0.1 nM CIF showed a 4-5 fold increase in proteoglycan synthesis. When cells were cultured with CIF alone on plastic, only small increases in proteoglycan synthesis were observed. Cells cultured with CIF in monolayer and then transferred to a permissive environment (either agarose or cultured with DHCB) showed enhanced synthesis of chondroblastic proteins. These results suggest that expression, but not induction, of a chondroblastic phenotype by CIF is inhibited by growth in monolayer. The altering of cell shape with DHCB releases that inhibition.

Animals↗

PubMedDate not supplied

A robotic system to prepare samples for HTLV-III testing.

A robotic handling system was adapted to perform the sampling and dilution steps needed in an assay to detect antibodies to the HTLV-III virus, the causative agent of AIDS. The system reduced the labor required to prepare the samples and provided standardization and accuracy in the preparation of the samples.

Antibodies, Viral↗