Biomedical subjects
Publications and source records attributed to L Sutton.
Evidence is presented that B+ null lymphocyte supernatants, previously shown to promote the growth of CD4+ T lymphocyte colonies from human marrow precursors, can also selectively enhance CD4+ T cell proliferative response to PHA and IL2.
Immunohistological techniques have been used to study the stromal cells of the human placenta in both the chorionic villous mesenchyme and the connective tissue underlying the amnion. Throughout gestation many of these cells express an antigen (3C10) that is found on mononuclear phagocytes but not on dendritic cells or epidermal Langerhans cells. In the first and second trimesters the placental cells also react with a monoclonal antibody (NA1/34) to the human thymocyte antigen (CD1), a lymphocyte differentiation antigen expressed by cortical thymocytes and Langerhans cells; expression of this antigen diminishes as gestation advances. In contrast, an antibody to a different epitope of CD1 (OKT6) does not bind. Class II MHC antigens are not present in the first trimester but are acquired by increasing numbers of placental macrophages from the second trimester onwards. It is possible that the placenta has significant immune functions and that, by term, placental macrophages may be capable of antigen presentation.
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The NMR and CT findings in 22 patients with primary brain stem tumors were compared to determine the value of each study in identifying, and delineating the extent and relationships of the tumor to brain anatomy. NMR was found to be distinctly superior to CT in showing involvement of the medulla and upper cervical cord. NMR eliminates the need for intrathecal enhanced metrizamide CT, and in the future should be the only initial diagnostic test needed for the evaluation of intrinsic brain stem tumors.
Escherichia coli strains determining 17 different plasmid-determined beta-lactamases were tested for resistance to new broad-spectrum beta-lactam antibiotics. Several beta-lactamases demonstrated enhanced resistance to cefamandole but only low-level resistance to other agents. High production of cloned E. coli chromosomal beta-lactamase, however, provided resistance to cefamandole, cefoxitin, cefotaxime, ceftazidime, and aztreonam but not to BMY-28142 or imipenem.
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Thirty IncP-2 R plasmids from isolates of Pseudomonas spp. of diverse geographical origins were examined for the production of resistance properties. All the plasmids determined resistance to tellurite and all inhibited the propagation of certain DNA phages, although several patterns of phage inhibition were detected. Of the 30 plasmids, 29 determined resistance to streptomycin, 28 determined resistance to mercuric ion, and 24 determined resistance to sulfonamide. Resistance to other antibiotics, to compounds of arsenic, boron, or chromium, and to UV irradiation was less common. The degradative plasmid CAM also belonged to this group. When CAM was introduced into recipients carrying an IncP-2 R plasmid, recombinant plasmids were often formed in which antibiotic resistance and the ability to grow on camphor were transferred together to further recipients or were lost together in a strain in which IncP-2 plasmids were unstable. Such hybrid plasmid formation was rec dependent. CAM and other IncP-2 plasmids that determine UV light resistance demonstrated UV-enhanced, nonpolarized transfer of the Pseudomonas aeruginosa chromosome. By agarose gel electrophoresis, all IncP-2 R plasmids and CAM were ca. 300 X 10(6) in molecular weight.
A population of heterogeneous HLA-DR positive cells has been identified in the human placenta and decidua using immunochemical and histochemical methods. These cells are found in three areas: the subepithelial layer of the amnion, the decidua, and more sparsely within the chorionic villous stroma. In addition to HLA-A, -B and -C antigens, they also express the leucocyte-common antigen, indicating their origin from bone marrow precursors. The majority have a characteristic stellate shape with many cytoplasmic processes. In the villous stroma these stellate cells can be distinguished from the Hofbauer cells (placental macrophages) by their morphology, stronger expression of HLA-DR and lack of lysosomal enzyme activity. In the amnion and decidua they cannot be clearly distinguished from tissue macrophages. By using monoclonal antibodies specific for foetal or maternal HLA-A or -B allotypes, the HLA-DR positive cells in the chorionic villi and the amnion have been shown to be foetal in origin. In contrast, most of the HLA-DR positive cells in the decidua are maternal; a few adjacent to the basal plate are foetal. The preponderance of these cells in those areas of the placenta where foetal and maternal tissues are in close proximity is striking. The possibility that some of the cells are equivalent to the dendritic cells that have been described in other tissues is discussed.
Previous studies demonstrated that NK resistant Epstein-Barr virus (EBV) carrying human lymphoblastoid cell lines become sensitive to NK cell-mediated destruction following induction of the viral cycle by superinfection with the P3HR-1 substrain of EBV or chemicals. In the present report we analysed the cellular membrane changes that were related to the development of sensitivity to NK activity in Raji cells with metabolic inhibitors. NK sensitivity does not develop in P3HR-1 superinfected Raji cells that are cultured in the presence of the RNA synthesis inhibitor actinomycin D and drops to half the amount usually detected in superinfected cells that are grown with the protein synthesis inhibitor cyclohexamide. In experiments with cyclohexamide blocks removed after 24 h, the target cell sensitivity to NK returns to normal levels. Control Raji cells cultured with the same inhibitors for up to 72 h do not develop any sensitivity to NK cell activity. These findings suggest that the development of sensitivity to NK destruction in Raji cells following superinfection is due to the addition to the cell membrane of a virally promoted molecule(s) that requires active RNA and protein synthesis.
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Development of the axial length of cat eyes was monitored through A-scan ultrasonography at various times after neonatal monocular lid suture. In every case the deprived eye was longer than its fellow eye. Upon reestablishment of the palpebral fissure, refractive state and corneal curvature were recorded. Although all the deprived eyes showed axial elongation, there was no consistent relationship between neonatal lid fusion and the degree of myopia.
Since October, 1978, 181 St Jude medical cardiac valves have been implanted in 166 patients throughout Australia. There were 152 single implants, 13 combined mitral and aortic valve implants, and one triple valve implant. Hospital mortality rates were similar to those for all types of prosthetic cardiac valves. Thromboembolic complications occurred less frequently in the patients with St Jude valves than in reports of similar patients with other prostheses, provided that anticoagulation was maintained.
Azlocillin, carbenicillin, cefsulodin, mezlocillin, nocardicin A, piperacillin, pirbenicillin, sulbenicillin, and ticarcillin, but not HR756, showed reduced activity against Pseudomonas aeruginosa strains producing seven types of beta-lactamase.
Directional characteristics of spinal injections delivered via a 22 gauge Whitacre needle were confirmed in twenty-one obstetric patients undergoing elective Caesarean section. Caudad injection was inadequate for elective Caesarean section, while cephalad or lateral injection provided good sensory levels for the duration of the surgery. It is speculated that along with the low incidence of postspinal headache and ease of administering the block with a more rigid 22 gauge needle, low dose caudally directed injections may provide a superior means of administering saddle block analgesia for obstetric patients.
Plasmid-containing strains of Pseudomonas aeruginosa were screened for resistance to disinfectants. Two plasmids, pMG1 and pMG2, were found to determine hexachlorophene resistance.