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Biomedical subjects

W Orr

Publications and source records attributed to W Orr.

51 records · Page 3Linked to original sources
PubMed1978

Characteristics of the chemotactic response of neoplastic cells to a factor derived from the fifth component of complement.

Chemotactic factors for malignant neoplastic cells can be generated from either the fifth component of complement or from leukotactic fractions obtained from zymosanactivated serum. Digestion of the fifth component of complement by trypsin initially produced leukotactic activity, but as digestion continues, leukotactic activity is lost and tumor cell chemotactic activity is generated. Separation of the leukotactic activity is lost and tumor cell chemotactic activity is generated. Separation of the leukotactic activity and tumor cell chemotactic activity can be accomplished by gel filtration or isoelectric focusing. Gel filtration indicates that the tumor cell chemotactic factor has a molecular weight of approximately 8000 daltons. Tumor cell chemotactic activity can be generated by trypsinizing the leukotactic fractions isolated by isoelectric focusing. The responses of cultured Walker tumor cells or of Walker ascites tumor cells are dose-dependent and truly chemotactic. Cells from a murine malignant lymphoma do not respond to the complement-derived chemotactic factor for tumor cells, indicating that not all malignant cells share this functional property.

Animals↗
PubMed1978

A comparison of the migration patterns of normal and malignant cells in two assay systems.

The migration patterns of normal mouse embryo fibroblast (MEF) cells and mouse fibrosarcoma (FS) cells were compared in two assay systems. The two assay systems used were themodified Boyden chamber (micropore membrane) assay and the agarose drop explant assay. In both assays the major population of MEF cells exhibited a greater rate of migration than the major population of FS cells. However, a small subpopulation of FS cells which had a much greater rate of migration than the major population of either MEF or FS cells was detected in the agarose drop assay. A number of drugs which are known to inhibit the migration of leukocytes were tested against the MEF and FS cells. Concentrations were found that inhibited the major population of both groups by greater than 90%. However, at concentrations which inhibited the migration of the major population of FS cells by greater than 90%, a small group of fast-moving cells was still detected. Although the fast-moving cells were relatively resistant to treatment with the various drugs, this group was sensitive to a factor in serum. When normal human serum was used in place of fetal calf serum, the migration of the major population of FS cells was inhibited very little but movement of the fast-moving population was completely eliminated. We speculate that the small subgroup of fast-moving cells may be responsible for the invasive nature of the FS cells.

Blood↗
PubMed1976

Allograft immunity to histocompatibility and organ-specific antigens.

An experimental model has been developed in the dog in which a renal allograft was placed in the neck, leaving one of the dog's own kidney in situ. Five nonimmunosuppressed pairs of dogs have been studied by using the leucocyte migration test (LMT) as an in vitro measure of cell-mediated immunity. Antigen preparations from leucocytes, kidney, liver, and skeletal muscle from both the kidney donor and the recipient were used in the LMT in order to study responses against transplantation and organ-specific antigens. Inhibition of migration with donor-specific leucocyte and kidney antigens was detectable prior to clinical evidence of rejection, which was confirmed histologically. Concurrently, inhibition was also observed with autologous kidney antigen and histological damage was noted in the recipient's own nontransplanted kidney, accompanied by increasing proteinuria. Autologous serum withdrawn daily and added to the test culture medium abolished the inhibition of migration, thus suggesting the development of blocking factor.

Animals↗
PubMed1975

Multispecific aspartate and aromatic amino acid aminotransferases in Escherichia coli.

Two aminotransferases from Escherichia coli were purified to homogeneity by the criterion of gel electrophoresis. The first (enzyme A) is active on L-aspartic acid, L-tyrosine, L-phenylalanine, and L-tryptophan; the second (enzyme B) is active on the aromatic amiono acids. Enzyme A is identical in substrate specificity with transaminase A and is mainly an aspartate aminotransferase; enzyme B has never been described before and is an aromatic amino acid aminotransferase. The two enzymes are different in the Vmax and Km values with their common substrates and pyridoxal phosphate, in heat stability (enzyme A being heat-stable and enzyme B being heat-labile at 55 degrees) and in pH optima with the amino acid substrates. They are similar in their amino acid composition, each enzyme appears to consist of two subunits, and enzyme B may be converted to enzyme A by controlled proteolysis with subtilsin. The conversion was detected by the generation of new aspartate aminotransferase activity from enzyme B and was further verified by identification by acrylamide gel electrophoresis of the newly formed enzyme A. The two enzymes appear to be products of two genes different in a small, probably terminal, nucleotide sequence.

Amino Acids↗
PubMed1975

The detection of hepatitis B antigen in hepatic parenchyma by the fluorescent antibody technic.

Tissue sections from 42 specimens of liver were examined by indirect immunofluorescence microscopy for the presence of hepatitis B antigen (HB Ag). In all cases the serologic status of HB Ag was known. Fourteen of the specimens were also examined by electron microscopy. In four biopsies from three patients positive cytoplasmic fluorescence was detected using antisera prepared in animals and 20-nm. nuclear particles were found by electron microscopy. These patients were all seropositive for HB Ag, all had chronic aggressive hepatitis or active cirrhosis, and all were receiving immunosuppressive therapy at the time of examination. Nuclear fluorescent staining was demonstrated when one of these biopsies was re-examined using a human antiserum.

Cell Nucleus↗
PubMedDate not supplied

Cystic angiomatosis of the bone appearing as intrathoracic lung masses.

A rare case of cystic angiomatosis of the bone (CAB) manifesting as bilateral intrathoracic masses is described. In 1996, a 47-year-old woman was referred to the chest clinic at St Boniface Hospital for evaluation of chronic cough, and her chest radiograph showed large, bilateral pleural-based intrathoracic masses. Ten years before, she had been diagnosed with CAB following bone biopsies of her hip and knee. Computed tomography revealed two chest wall masses with internal septations of bone. CAB is a rare, multicentric disease characterized by involvement of the vascular and lymphatic systems, producing diffuse cystic lesions in the skeleton. Although the ribs are frequently involved, the presentation with intrathoracic masses is uncommon.

Angiomatosis↗