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A Edwards

Publications and source records attributed to A Edwards.

At least 37 records · Page 2Linked to original sources
PubMed1989

The place of lung 99mTc DTPA aerosol transfer in the investigation of lung infections in HIV positive patients.

Pneumocystis carinii pneumonia (PCP) is the most common cause of pneumonia in HIV antibody positive patients, but other pneumonias remain important, i.e. streptococcal and mycobacterial infections. A definitive diagnosis relies on obtaining samples from the lung either noninvasively (induced sputum), or invasively (bronchoalveolar lavage, transbronchial or open lung biopsy). We have used the noninvasive technique of nebulized 99mTc DTPA transfer, to assess patients with PCP (n = 30) and other lung infections (n = 20) to see whether this test will distinguish between the various infections. The presence of a biphasic, rapid transfer curve indicates severe extensive alveolar damage and is seen in PCP or legionella pneumonia. The mean transfer time (T50 +/- SEM) for patients with PCP (whether smokers or nonsmokers) was 2.1 +/- 0.2 min, and for two of the patients with legionella 3.2 min. In PCP effective treatment causes the transfer to slow (mean T50 22.7 +/- 3.3 min, n = 24) and become monoexponential. Other causes of these changes in transfer are discussed. The other pneumonias (streptococcal, mycobacterial, and staphylococcal) did not result in biphasic curves or very rapid times, their T50 values are indistinguishable from cigarette smokers. In this patient group the DTPA transfer is a useful noninvasive investigation with a very rapid, biphasic curve indicating a high probability of PCP.

Adult↗
PubMed1989

Characterization of muscarinic receptors: type M2 (subtype B) on neuro-2A neuroblastoma cells.

The binding of the nonselective muscarinic antagonist, [3H]N-methylscopolamine (NMS) to a mouse neuroblastoma cell line (Neuro-2A) and its coupling to the inhibition of adenylate cyclase were characterized. Specific [3H]NMS binding to membrane preparations was rapid, saturable, and of high affinity. Saturation experiments revealed a single class of binding sites for the radioligand. Competition experiments with the muscarinic drugs pirenzepine, AF DX 116, dicyclomine and atropine revealed that the muscarinic receptors present on these cells are predominantly of a single class, subtype B (M2). In addition, agonist binding demonstrated existence of a GTP-sensitive high affinity binding state of the receptors. Coupling of these muscarinic receptors to the adenylate cyclase system was investigated using the muscarinic agonist carbachol which was able to inhibit the prostaglandin (PGE1)-stimulated activation of adenylate cyclase. The agonist carbachol did not stimulate the formation of IP3 above basal levels, which indicated that the receptors are not coupled to phosphatidylinositol metabolism. In conclusion, we show that possessing predominantly one subtype of muscarinic receptor, the Neuro-2A cells provide a useful model for the investigation of the heterogeneity of muscarinic receptors and the relationship of subtype to the coupling of different effectors.

Animals↗
PubMed1989

Accessory and T cell defects in acquired and inherited hypogammaglobulinaemia.

Cellular defects in patients with common variable hypogammaglobulinaemia (CVH) and X-linked agammaglobulinaemia (XLA) have been studied in vitro, using a mitogen-driven system of immunoglobulin production. We have confirmed our previous finding of impaired low-density (dendritic) accessory cell function in CVH and now show that accessory cell function is normal in XLA. We demonstrate that macrophage accessory function is normal in CVH. T cell help for IgM production is also deficient in CVH, and T cell help in XLA is also abnormal for both IgG and IgM. Some XLA patients have excessive T suppressor activity. The contribution of these defects to the clinical states is discussed.

Agammaglobulinemia↗
PubMed1988

Podophyllotoxin 0.5% v podophyllin 20% to treat penile warts.

The increasing incidence of genital warts has led to more public awareness of this infection and its possible sequelae. Currently available treatment remains unsatisfactory, and there is pressure to develop effective and convenient alternatives. Podophyllotoxin is standardised and stable, whereas podophyllin has a variable composition. In an open comparison of self applied podophyllotoxin 0.5% versus podophyllin 20% applied by a doctor to treat external penile warts, podophyllotoxin was more effective and gave quicker resolution than podophyllin. Side effects were similar for both preparations, and few patients experienced complications severe enough to stop treatment. Podophyllotoxin can therefore be used safely and effectively for home treatment monitored at an outpatient clinic and provides a useful alternative to treatment with podophyllin at overburdened genitourinary medicine clinics.

Adult↗
PubMed1988

Immunocytochemical localization by electron microscopy of 2'3'-cyclic nucleotide 3'-phosphodiesterase in developing oligodendrocytes of normal and mutant brain.

Oligodendrocytes or their putative progenitors were the only cells found to be immunoreactive to polyclonal antisera against the enzyme 2'3'-cyclic nucleotide 3'-phosphodiesterase (CNP) in developing and mature brains of rats and mice, as visualized by light and electron microscopy. Prior to myelination (day 6), oligodendrocytes of the corpus callosum have reticular networks of CNP-containing filopodia, in addition to abundant CNP throughout the cytoplasm. Some glioblast-like cells of the subventricular zone are also immunoreactive to anti-CNP, suggesting that, as progenitors of oligodendroglia, they express this myelination-related protein as one of the earliest events in myelinogenesis. Following the commencement of myelination (day 15), many oligodendrocytes lose much of their lacelike network of fine projections, possessing, instead, larger CNP-filled processes that extend to myelin-bearing fibers. CNP was always found only in the cytoplasm-containing compartments of the cells and myelin sheaths; neither lamellae nor cellular membranes were immunostained. These data support our contention that CNP is not an intrinsic membrane protein, despite its strong interaction with membrane components when cells are disrupted. In mutant (mld) mice (day 25), the many distended and uncompacted oligodendroglial processes that invest axons with only a few turns of membrane contained cytoplasmic CNP, accounting for the elevated levels of CNP activity previously noted in tissue fractions.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1987

Evidence that treatment with vaccinia melanoma cell lysates (VMCL) may improve survival of patients with stage II melanoma. Treatment of stage II melanoma with viral lysates.

A total of 80 patients with melanoma metastases in regional lymph nodes were treated by i.d. injections with a vaccine prepared from a vaccinia virus-infected allogeneic melanoma cell line; 39 patients have been followed for a 2-year period. Interim results from comparison of the treated group with 151 historical controls treated without the vaccine from September 1978 to December 1981 at the same institution and 56 non-randomized concurrent controls suggest that survival was significantly prolonged in the vaccinated group. At the 2-year period overall survival was 75% in the treated compared to 57% in the historical control group. Subset analysis showed a greater apparent benefit of vaccine therapy among patients who had metastases detected at the time of treatment of the primary melanoma (synchronous metastases), while therapy appeared less effective in patients with metastases detected at some time after treatment of the primary (delayed metastases). In the latter only those with one lymph node appeared to benefit from the treatment whereas in patients with synchronous metastases patients with three or more nodes as well as one node appeared to have improved survival. The survival rates at 2 years for treated patients with synchronous metastases in one, two, three or more lymph nodes was 100%, 83% and 79% respectively compared with that of 82%, 86% and 47% respectively in the equivalent control groups. Survival rates in treated patients with delayed metastases in one, two, three or more lymph nodes was 70%, 70% and 65% compared with 47%, 42% and 35% in the equivalent control groups. Treatment and control groups appeared well matched for a number of known prognostic features, including number and size of involved nodes, sex and thickness of primary tumor. Multivariate analysis indicated the effect of treatment was independent of these factors. Despite the empiricism of this approach the present results suggest that this form of therapy warrants further evaluation in a randomized controlled trial.

Adolescent↗
PubMed1987

Alveolar permeability in HIV antibody positive patients with Pneumocystis carinii pneumonia.

Pulmonary permeability was assessed using the technique of 99mTc (technetium-99m) diethylene triamene pentacetic acid (DTPA) aerosol transfer in 10 patients who had antibodies to human immunodeficiency virus (HIV) and were non-smokers and in 20 HIV antibody positive smokers. Five patients had Pneumocystis carinii pneumonia (PCP) proved by transbronchial lung biopsy; four were non-smokers and one a smoker. Two findings emerged: patients with PCP had greater epithelial permeability than non-smokers and smokers; and the permeability curves were monophasic in smokers and non-smokers, but biphasic in patients with PCP. The biphasic curve observed is indicative of diffuse alveolar damage and might be useful to predict PCP in patients with antibodies to HIV who have normal chest radiographs. As the study was of only five patients with PCP, however, further studies are necessary to confirm this observation.

Adult↗
PubMed1986

The effect of desferrioxamine on transferrin receptors, the cell cycle and growth rates of human leukaemic cells.

The effect of the iron chelator, desferrioxamine, on transferrin binding, growth rates and the cell cycle was investigated in the human leukaemic cell line, K562. At all concentrations of the chelator (2-50 microM) binding of 125I-transferrin was increased by 24 h and reached a maximum at 72-96 h. Maximum binding (6-8-fold increased) occurred in cells treated with 20 microM-desferrioxamine, in contrast with control cells which, at 96 h, showed a 50% decrease over initial binding. Scatchard analysis at 4 degrees C showed that this increased binding was due to an increase in the number of receptors, as the Kd was similar in induced (1.8 nM) and control (1.5 nM) cells. After 96 h cells, cultured with 20 and 50 microM-desferrioxamine accumulated 59Fe from bovine transferrin at over twice the rate found with control cells, reflecting the increase in transferrin receptors. Although iron uptake was unimpaired by the chelator there was a dose-dependent inhibition of cell growth, with control cells completing three divisions in 96 h and those in 10 microM-desferrioxamine only two divisions. At the highest concentration (50 microM), cell division was abrogated although cell viability was maintained (85%). In contrast, DNA synthesis was not markedly affected, except at 50 microM-desferrioxamine when incorporation of [3H]thymidine was 52% of that in control cells. Flow cytometry revealed that there was a progressive accumulation of the cells in the active phases of their cycle (S, G2 + M). Desferrioxamine may increase transferrin receptors in two ways: by chelating a regulatory pool of iron within the cell, and by arresting cells in S phase when receptors are maximally expressed.

Cell Cycle↗
PubMed1986

Immunological effects of recombinant interferon alfa-2a in patients with disseminated melanoma.

Twenty patients with disseminated melanoma were treated with interferon alfa-2a, given by intramuscular (IM) injection three times a week in escalating doses from 15 to 50 X 10(6) U/m2. Of 18 patients considered evaluable, two had complete remission and in two others the disease was stabilized. Laboratory tests 6 hours after injection of interferon alfa-2a indicated a marked lymphopenia and a reduction in natural killer (NK) cell activity. Sequential changes (measured before injection of interferon alfa-2a on days 3, 10, and 31) consisted of neutropenia, thrombocytopenia, and a slight increase in OKT4 positive T cells compared with OKT8 positive T cells. NK activity against the K562 target cells was increased in most patients during the first week of treatment, returning to near or below pretreatment levels thereafter. This response contrasted with a delayed increase against melanoma target cells in 10 patients. The latter correlated with an increase in mitogen-stimulated interleukin-2 (IL2) production, and may indicate that the cytotoxic activity resulted from lymphokine-activated killer (LAK) cells. Changes in cortisol levels may explain some effects on the immune system, such as depression of IL2 and immunoglobulin production in vitro, and the differences noted in clinical responses during the present study compared with those observed with interferon alfa-2b given by intravenous (IV) injection in 5-day cycles. These results suggest that interferon alfa-2a has antitumor activity in certain melanoma patients, in particular those with metastases to pulmonary or subcutaneous sites. Assays of IL2 production and LAK activity may assist in the selection of patients who respond to interferon alfa-2a and help to optimize treatment regimens.

Adult↗
PubMed1986

Phase II study of vaccinia melanoma cell lysates (VMCL) as adjuvant to surgical treatment of stage II melanoma. II. Effects on cell mediated cytotoxicity and leucocyte dependent antibody activity: immunological effects of VMCL in melanoma patients.

Patients with stage II melanoma were vaccinated with vaccinia virus-induced melanoma cell lysates (VMCL). The vaccine contained viable vaccinia virus, membranous fragments and no intact nuclei. A number of antigens defined by monoclonal antibodies were detected in the vaccine including the ganglioside GD3 and DR antigens. Administration of the vaccine was associated with depression of natural killer cell activity against melanoma and K562 target cells in the first 3-6 months of treatment. Leucocyte dependent antibody (LDA) activity against melanoma cells was induced or increased in titre in approximately half of the patients studied. Continued vaccination was associated in a number of patients with a decrease in LDA titres. Studies on a small sample of patients revealed that this was associated with the development of serum factors which inhibited LDA activity. LDA activity appeared directed to non-MHC antigens on melanoma cells which were of at least two specificities. One specificity which was shared with antigens on a number of non-melanoma carcinoma cells was removed by absorption on fetal brain and may be similar to oncofetal antigens described by other workers. Reactivity against melanocytes was induced in some patients and may underline the development of vitiligo in several patients. These results suggest that vaccines prepared from VMCL may be a favourable method for increasing immune responses against melanoma.

Antibodies, Neoplasm↗
PubMed1986

Mixed function oxidase activity in the harbour seal (Phoca vitulina) from Sable Is., N.S.

One adult male, eight pups (including two full term foetuses) and nine adult female harbour seals (Phoca vitulina) were analysed for indices of mixed function oxidase (MFO) activity. MFO activity was present in liver samples, but was at or below detection limits in samples of kidney, lung and pancreas. Hepatic ethoxyresorufin O-de-ethylase and benzo[a]pyrene hydroxylase activities were similar to those reported in other seals and in other mammals. Cytochromes P-450 and b5 concentrations were slightly lower than those observed in other mammals. MFO activities in newborn pups and foetuses were significantly lower than those in adult females. No qualitative differences in cytochrome P-450 isozyme distribution between foetal and adult samples could be discerned by electrophoresis.

Animals↗
PubMed1986

Comparative study on the effects of recombinant alpha-2 interferon on immune function in patients with disseminated melanoma.

Fifteen patients with disseminated melanoma were treated by intravenous administration of recombinant alpha-2 interferon (rIFN-alpha 2) on 5 consecutive days every 2 weeks. Immunological studies on approximately 50% of the patients revealed no significant changes in lymphocyte numbers or T-cell subsets. Natural killer (NK) activity against the K562 target cell and a melanoma cell was increased in the first treatment cycle, but in subsequent treatment cycles it tended to decrease against the melanoma cell and to show either no change or moderate increases against the K562 target cell. Interleukin-2 (IL-2) production from mitogen-stimulated lymphocytes was decreased in most patients in each treatment cycle. This also applied to immunoglobulin production in vitro from pokeweed mitogen (PWM)-stimulated B and T cells. The latter was not due to the induction of radiation-sensitive suppressor T cells and may reflect effects on B cells or helper T cells. The repeated inhibition of IL-2 production with each cycle of treatment and the decrease in NK activity against the melanoma target cells after the first treatment cycle contrasted with the return to at or above pretreatment values of these tests when rIFN-alpha A was given intramuscularly on an alternate-day basis. It is suggested that these effects may be due to the relatively greater increase in endogenous cortisol production at the beginning of each treatment cycle in patients given rIFN-alpha 2 intravenously compared to that observed in patients treated with rIFN-alpha A on alternate days intramuscularly. Immunosuppression resulting from the increase in cortisol production may be one of the factors accounting for the low tumor response rate of patients in this study and may emphasize the possible importance of the schedule of rIFN-alpha administration for obtaining optimal antitumor responses.

Adult↗