Biomedical subjects
Publications and source records attributed to A Boyd.
New vectors expressing protein A fusions were constructed, based upon the kanamycin-resistance-encoding plasmid, pK19. They were designed for use in combination with the pEX series of beta-galactosidase protein-fusion vectors in the production and affinity purification of specific antibodies.
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1. This study was designed to test the hypothesis that three-carbon intermediates can be used in the 'indirect' pathway of glycogen synthesis in human liver (i.e. a route additional to the use of glucose by the 'direct' pathway). 2. After an overnight fast, 13 patients were given an infusion of 20% (w/v) glucose before elective abdominal operation. All received a 2.5 g bolus of 2220 kBq of selectively 3H- and 14C-labelled glucose before removal of a 1 g biopsy of liver. 3H and 14C were determined in purified glycogen as well as in glucose and lactate from samples of peripheral blood. 3. The ratio and specific activities of 3H and 14C in glycogen were found to be significantly lower than those in administered glucose. By calculation, 7-74% of glycogen repletion occurred by indirect pathways and not all of this was from the glucose supplied. 4. This study suggests that the operation of a direct pathway in man is not exclusive and that significant repletion of hepatic glycogen occurs by an indirect route.
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The clinical course of 312 consecutive patients after initial presentation with metastatic melanoma, 165 of whom presented with regional metastases at cutaneous or subcutaneous, or both, nodal sites and 147 with metastases at distant sites, was reviewed. The five year survival rate for regional metastases was 43.4 per cent compared with a five year survival rate for distant metastases of 4.9 per cent (p less than 0.0001). Favorable prognostic variables for survival from first regional metastases included primary melanoma sites on the extremities compared with the head, neck and trunk (p = 0.043) and a disease-free interval of more than one year from primary surgical treatment to regional metastases (p = 0.0058). Favorable prognostic variables for survival from the first distant metastasis included a disease-free interval of more than one year from primary surgical treatment to distant metastases (p = 0.0092), the type of resection of metastatic disease (p = 0.00027) and the addition of systemic immunotherapy (p = 0.0011). Forty-nine patients with totally resectable distant metastases had a five year survival rate from the treatment of the initial metastasis of 13.1 per cent, whereas 33 patients having palliative resections had a five year survival rate of 7.5 per cent. All 165 patients who did not have resection for distant metastases died within five years. The results of our experience support therapeutic efforts to ablate both regional and distant metastases of malignant melanoma when feasible.
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The outcome of 29 patients who underwent lung resection for treatment of metastatic malignant melanoma from January 1976 to November 1988 was studied. Twenty-two patients underwent total resection for cure of all apparent metastatic disease, whereas seven patients did not undergo total resection. Of the 22 patients who underwent curative resection, the median survival was 11 months, with a 2-year survival of 13.6% and a 5-year survival of 4.5%. Four patients who underwent curative resection are currently alive and free of disease, with one patient surviving more than 10 years. The patients who underwent palliative resection had a median survival of 5 months, only one patient living longer than 10 months. The difference in survival of the patients who underwent curative resection compared with palliative resection was statistically significant. The thickness of the primary cutaneous malignant melanoma, the presence of regional lymph node metastases, the disease-free interval from primary diagnosis to metastatic pulmonary disease, and whether one or two metastatic nodules were removed during curative lung resection were not statistically significant in altering survival. These results demonstrate that although prolonged survival for metastatic melanoma is rare, lung resection in selected patients may be associated with long-term survival.
The very low expression of insulin receptors in the Burkitt lymphoma cell Raji was increased 2-fold, 6-fold and 10-fold after 1, 2 and 3 days, respectively, by incubation with the differentiation inducer sodium butyrate. Insulin receptor number was increased without a change in receptor affinity, in association with an increase in the receptor alpha and beta subunits detected after cell-surface labelling and immunoprecipitation. Expression of cell-surface class I and II human leukocyte antigens, the intercellular adhesion molecule-1 and the CD38 leukocyte antigen was also increased, consistent with B cell differentiation. Butyrate effects were not unspecific, as the binding of tumour necrosis factor and growth hormone and the expression of the B cell markers CD20, B5 and CD21 was not increased. The low expression of insulin receptors on Raji cells is therefore a reflection of the less differentiated state of these cells compared to lymphoblastoid cells.
STUDY OBJECTIVE: To define the clinical and hematologic effects of subcutaneously administered bacterially synthesized recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF). DESIGN: Single arm nonrandomized dose escalation study. PATIENTS: Twenty-one patients with advanced malignancy who were not receiving concurrent myelosuppressive therapy. INTERVENTIONS: Subcutaneous administration of rhGM-CSF by once-daily injection to groups of two to four patients at doses of 0.3 to 30 micrograms/kg body weight.d for 10 consecutive days. Some patients received a second 10-day period of daily rhGM-CSF treatment after a 10-day nontreatment interval followed by alternate-day treatment. Clinical status and hematologic values were monitored frequently. MEASUREMENTS AND MAIN RESULTS: All doses of rhGM-CSF caused an immediate transient fall of 84% to 99% in circulating neutrophils, eosinophils, and monocytes. Continued daily dosing caused a leukocytosis of up to 10-fold with increases in numbers of circulating neutrophils, eosinophils, monocytes, and lymphocytes. There appeared to be a plateau in the increase in neutrophils in the dose range 3 to 15 micrograms/kg.d. Marrow aspirates showed increased proportions of promyelocytes and myelocytes. Alternate-day injection of 15 micrograms/kg maintained a leukocytosis. At doses up to 15 micrograms/kg.d, rhGM-CSF was well tolerated but adverse effects included bone pains, myalgias, rashes, and liver dysfunction. At doses exceeding 15 micrograms/kg.d, pericarditis was a dose-limiting toxicity. Idiopathic thrombocytopenic purpura was reactivated by rhGM-CSF in one patient. CONCLUSIONS: Bacterially synthesized rhGM-CSF induces a leukocytosis in the dose range of 3 to 15 micrograms/kg.d. These doses are appropriate for phase II studies.
This study has shown that Klebsiella pneumoniae strain K21 differs from the previously characterized and closely related K. pneumoniae strain PAP996 in that expression of the pullulanase gene (pulA) and other genes of the maltose regulon is partially independent of exogenous inducer (maltose/maltotriose). Mutants of strain K21 which are defective in pullulanase synthesis and/or secretion were isolated following Tn10 mutagenesis. Three phenotypic classes of mutants were identified. Class I mutants were defective in the surface localization and secretion of pullulanase. Class II mutants did not secrete detectable levels of pullulanase but were able to export pullulanase to the cell surface. Class II mutants also expressed pullulanase and other maltose-regulated genes at markedly lower levels than those found in the parent strain under non-inducing conditions. The single class III mutant was intermediate between K21 and class I mutants; most of the cell-associated pullulanase was localized at the cell surface whilst a significant amount was secreted into the medium. Mapping indicated that all but three of the Tn10 insertions were adjacent to, and at either side of, pulA. One class II mutant carried a Tn10 insertion in or close to malT whereas in the remaining class II mutants the insertions were located at least 4 kb upstream of pulA in a region which may define a new regulatory locus of the maltose operon.
Klebsiella pneumoniae strain PAP996 was previously shown to secrete fatty acylated, aggregated (micellar) pullulanase only after the end of exponential growth. Here we show that the closely related strain K21 secretes large amounts of unacylated, non-aggregated (monomeric) pullulanase during exponential growth. Only a small amount (less than 10%) of the secreted pullulanase was initially retained by the exponentially growing cells to be subsequently secreted in a fatty acylated, aggregated form. Despite the absence of fatty acids in secreted monomeric pullulanase, the effects of the antibiotic globomycin on pullulanase maturation indicated that all of the enzyme synthesized by strain K21 is processed by lipoprotein signal peptidase.
The killer toxin of Kluyveromyces lactis consists of three polypeptides encoded by the linear plasmid k1. We re-introduced the entire k1 sequence, cloned on a circular replicating plasmid, into K. lactis strains lacking k1, and found that the resulting transformants did not produce toxin. The barrier to expression was found to be transcriptional: the four transcripts of native k1 were absent, and instead shorter, aberrant k1 transcripts were made. We determined the precise initiation sites of the four transcripts of native k1: these had very short untranslated leaders and mapped about 14bp downstream of an "upstream conserved sequence" (UCS). It appears that k1 has novel promoters which are inactive on circular plasmids which replicate in the nucleus. This is consistent with the suggestion that native k1 resides in the cytoplasm.
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Reconstruction of a large postmastectomy irradiated chest wall defect was accomplished with a large musculocutaneous free flap of anterolateral thigh musculature and skin. The vascular anatomy of the donor area allows a very substantial flap and skin island to be transferred, leaving a well-tolerated donor defect.
Anastomotic fistulae are uncommon complications after gastrointestinal surgery. We describe an unusual case of an esophagocolonic stricture after colonic interposition for benign disease complicated by proximal esophageal fistulae successfully treated with balloon dilation.
Following the observation that mouse interleukin 5 (IL5) is active as a B cell growth factor (BCGF) as well as an eosinophil differentiation factor, this work was carried out to test recombinant human IL5 for BCGF activity. A highly active, partially purified batch of recombinant human IL5 was prepared and tested for BCGF activity in four laboratories. This batch gave a 50% endpoint of 1:77,450 in the human eosinophil differentiation assay, 1:983 in the mouse eosinophil differentiation assay and 1:42 in the mouse BCL1 assay, thus demonstrating that, like mouse IL5, human IL5 has cross-species activity. By comparison with the assays in the mouse this batch would be expected to have 50% maximal human BCGF activity of about 1:4000. In each assay a known positive factor was used as a positive control, and there was no inhibitory activity in the preparation. However, despite the activity towards the mouse B cell lymphoma, the results showed no detectable activity in a panel of assays used to identify human BCGF and B cell differentiation factors. These assays included (a) proliferation assays with tonsillar or splenic B cells in the presence of the co-stimulators anti-mu or phorbol myristate acetate; (b) a restimulation assay in which tonsillar B cells are first activated with either Staphylococcus aureus Cowan 1 or a mixture of phorbol dibutyrate and ionomycin, or splenic B cells are first activated with anti-mu; (c) production of immunoglobulin by B cells in a restimulation assay with Staphylococcus aureus Cowan 1; (d) production of immunoglobulin by the Epstein-Barr virus-transformed B lymphoblastoid CESS cell line; (e) the ability to stimulate proliferation of chronic lymphocytic leukemia (B-CLL) cells freshly explanted from three different patients; (f) the ability to stimulate the B lymphoma (L4) cell line and the mature B cell (HBF1) line, and (g) the ability to replace T cells in specific antibody responses. It therefore seems unlikely that recombinant human IL5 is either a growth or a differentiation factor for human B cells, and raises the interesting question of the biological significance of the BCGF activity of this factor in the mouse.
Total serum tryptophan concentrations were measured in 74 cataractous patients and 124 controls. No significant differences were observed in the mean values for the cataractous and normal subjects, 11.4 +/- 2.6 and 11.3 +/- 2.2 micrograms/ml respectively, or in the range of values, 7.4-17.1 and 7.3-17.4 micrograms/ml respectively. These results do not support previous reports that serum tryptophan is elevated in cataractous subjects.