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D Logan

Publications and source records attributed to D Logan.

At least 37 records · Page 2Linked to original sources
PubMed1993

Structure of a major immunogenic site on foot-and-mouth disease virus.

Attachment of foot-and-mouth disease virus (FMDV) to its cellular receptor involves a long and highly antigenic loop containing the conserved sequence, Arg-Gly-Asp, a motif known to be a recognition element in many integrin-dependent cell adhesion processes. In our original crystal structure of FMDV the Arg-Gly-Asp-containing loop ('the loop'), located between beta-strands G and H of capsid protein VP1, was disordered and hence essentially invisible. We previously surmised that its disorder is enhanced by a disulphide bond linking the base of the loop (Cys 134) to Cys 130 of VP2 (ref. 8). We report here the crystal structure of the virus in which this disulphide is reduced. Reduced virus retains infectivity and serological experiments suggest that some of the loop's internal structure is conserved. But here its structure has become sufficiently ordered to allow us to describe an unambiguous conformation, which we relate to some key biological properties of the virus.

Aphthovirus↗
PubMed1993

Inhibition of HIV-1 replication by daunorubicin.

Members of the anthracycline family of drugs such as daunorubicin (DNR) are currently being employed in cancer therapy, treatment of Kaposi's sarcoma and lymphomas in HIV-1 infected patients. These drugs may have an anti-viral activity against HIV-1. Experiments conducted on U937 (a promonocytic cell line), peripheral blood monocytes (without T cells) and infected with HIV-1 showed anti-viral activity at nanogram/ml concentrations, without affecting cell proliferation and cell viability. Treatment of Hut 78 cells (a T cell line) with DNR was not as effective in inhibiting HIV-1 replication when compared to the anti-HIV activity in cells of the monocyte lineage.

Antiviral Agents↗
PubMed1992

Crystallization and preliminary X-ray analysis of three serotypes of foot-and-mouth disease virus.

Foot-and-mouth disease viruses from serotypes O, A and C have been crystallized. The particular strains studied include O1K, A10(61), A22 Iraq 24/64, A24 Cruzeiro and C-S8c1. In addition, crystals have been grown of G67, a monoclonal antibody neutralization escape mutant derived from O1K, and of virus R100, recovered after the establishment of a persistent infection in baby hamster kidney cells with C-S8c1. Empty particles, capsids which lack the RNA genome, have also been crystallized for subtypes A22 Iraq 24/64 and A10(61). In almost all cases, crystals suitable for high resolution structure determination were obtained from (NH4)2SO4 or mixtures of polyethylene glycol and NH4Cl.

Aphthovirus↗
PubMed1992

Ifosfamide, cisplatin, and etoposide (ICE) in the treatment of advanced non-small cell lung cancer.

Forty-seven previously untreated patients with histologically or cytologically proven non-small cell lung cancer were treated with ICE (ifosfamide/cisplatin/etoposide). Patients received ifosfamide 4 g/m2 with mesna uroprotection on day 1, and cisplatin 25 mg/m2/d and etoposide 100 mg/m2/d on days 1, 2, and 3; courses were repeated every 28 days. Premedication with prochlorperazine, dexamethasone, and high-dose metoclopramide was given to prevent nausea; lorazepam was added on days 2 and 3 only. Thirty-four men and 13 women (median age, 60 years) received a total of 146 treatment cycles. One patient had stage IIIA disease, seven had IIIB disease, and 39 had hematogenous metastases. Forty-six patients were evaluable for response and toxicity. One patient suffered a myocardial infarction on day 7 that was judged unrelated to treatment. Two patients suffered early death from toxicity and have been classified as nonresponders. Three patients achieved complete response (median, 42+ weeks) and 14 patients achieved partial response (median, 29+ weeks; range, 10 to 82+), for an overall response rate of 37% (95% confidence limits, 23% to 51%). The median survival of the entire group is 26 weeks (1 to 82+). The median nadir granulocyte count was 0.275 x 10(9)/L (range, 0 to 2.3 x 10(9)/L), and there were 14 episodes (in 11 patients) or neutropenia-associated fever, one of which resulted in death. Seven of these patients had not had the required protocol dose reduction for nadir neutrophil count in the preceding cycle. The median nadir platelet count was 120 x 10(9)/L (range, 13 to 385 x 10(9)/L), and three patients required platelet transfusions. Eleven patients had RBC transfusions. Only ten patients had grade 2 gastrointestinal toxicity. Five patients had microscopic hematuria, and one patient had central nervous system toxicity.

Adult↗
PubMed1992

A phase II study of ifosfamide in combination with etoposide and cisplatin in the treatment of extensive small cell lung cancer.

The combination of etoposide and cisplatin has become one of the standard treatments for small cell lung cancer. Ifosfamide, an analogue of cyclophosphamide, has demonstrated single-agent antitumor activity comparable with that of the most active agents used to treat small cell lung cancer. Because ifosfamide is relatively nonmyelosuppressive and its principal dose-limiting toxicity, urotoxicity, has largely been eliminated with the introduction of the uroprotective agent mesna, we undertook a phase II study of the combination of all three agents (etoposide/ifosfamide/cisplatin) in good-performance-status, extensive-disease patients 70 years of age or younger. Twenty-five patients (17 men and eight women; median age, 58 years) were treated with 75 mg/m2 etoposide, 20 mg/m2 cisplatin, and 1.0 g/m2/d ifosfamide administered intravenously for 5 days. Mesna (200 mg/m2) was given as a bolus prior to the first day of chemotherapy and then daily by continuous infusion (900 mg/m2 over 24 hours) between administrations of chemotherapy. Mesna was continued for 12 hours after the last dose of ifosfamide. Treatment cycles were planned every 4 weeks for four cycles. Due to severe toxicities in the first eight patients, subsequent patients received only 4 days of treatment (20% dose reduction). Of the 25 extensive-disease patients studied, 23 are evaluable for response. Seven (30%) achieved a complete response and 10 (43%) had a partial response (overall response rate, 73%). Five patients (22%) had stable disease (< 50% decrease and no evidence of disease progression for at least 4 weeks), and disease progressed in 1 patient (4%). The median survival time was 42 weeks (range, 2 to 160+ weeks). Granulocytopenia was dose-limiting: median granulocyte count was 0.486 x 10(9)/L, 21% of cycles had a granulocyte nadir below 0.2 x 10(9)/L, and four patients died of sepsis. Three patients required platelet transfusion and nine needed blood transfusion. Microscopic hematuria occurred in eight patients (11% of treatment cycles) but was reversible in all cases. A number of central nervous system symptoms were reported but could not be definitely attributed to ifosfamide/mesna. Gastrointestinal toxicity was generally mild, which is attributed to the use of an aggressive antiemetic program. The etoposide/ifosfamide/cisplatin regimen is active and produced a complete response rate of 30% in extensive small cell lung cancer; the duration of response and survival appears similar to that of other standard regimens. The 5-day schedule produced excessive toxicity in this patient population, necessitating a 20% dose reduction (by using a 4-day schedule). The method of administration required a minimum of 5 hospital days per cycle.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Structural and serological evidence for a novel mechanism of antigenic variation in foot-and-mouth disease virus.

Changes resulting in altered antigenic properties of viruses nearly always occur on their surface and have been attributed to the substitution of residues directly involved in binding antibody. To investigate the mechanism of antigenic variation in foot-and-mouth disease virus (FMDV), variants that escape neutralization by a monoclonal antibody have been compared crystallographically and serologically with parental virus. FMDVs form one of the four genera of the Picornaviridae. The unenveloped icosahedral shell comprises 60 copies each of four structural proteins VP1-4. Representatives from each of the genera have similar overall structure, but differences in the external features. For example, human rhinovirus has a pronounced 'canyon' that is proposed to contain the cell attachment site, whereas elements of the attachment site for FMDV, which involves the G-H loop (residues 134-160) and C-terminus (200-213) of VP1, are exposed on the surface. Moreover, this G-H loop, which is a major antigenic site of FMDV, forms a prominent, highly accessible protrusion, a feature not seen in other picornaviruses. It is this loop that is perturbed in the variant viruses that we have studied. The amino acid mutations characterizing the variants are not at positions directly involved in antibody binding, but result in far-reaching perturbations of the surface structure of the virus. Thus, this virus seems to use a novel escape mechanism whereby an induced conformational change in a major antigenic loop destroys the integrity of the epitope.

Antibodies, Monoclonal↗
PubMed1990

Naturally occurring human IgG antibodies to intracellular and cytoskeletal components of human platelets.

Immunoblotting of platelets that have been subjected to SDS-PAGE has revealed that sera from normal individuals contain IgG which binds to many platelet components. This binding was seen with autologous and heterologous platelets using serum of males and of nulliparous females who had not received blood transfusions. Although binding patterns of different sera were not identical, almost all sera caused IgG binding to platelet components of 87-90 kD, 140 kD (identified as vinculin) and 220-240 kD (tentatively identified as talin and actin-binding protein). Purified IgG showed the same binding pattern as whole serum and F(ab')2 fragments retained their ability to bind to many components. The titre of IgG binding in serum was 1:50-1600 while that of alloantibodies to the PlA1 antigen was 1:3200. IgG binding components were not secreted when platelets were stimulated and were rarely associated with isolated membranes, but were located either in platelet cytoplasm or cytoskeletons. IgG binding was decreased by absorbing sera with lysed platelets or isolated cytoskeletons, but only slightly with intact platelets. Microaffinity purification of IgG which formed a major band on immunoblots showed that it was antibody with specificity for vinculin or its degradation products. These findings suggest that normal sera contain naturally occurring IgG antibodies with specificity for intracellular platelet antigens and that in some cases their titre approaches that of antibodies of pathological significance.

Adult↗
PubMed1990

A phase II study of ifosfamide, cisplatin, etoposide in patients with advanced non-small cell lung cancer: a preliminary report.

Twenty previously untreated patients with histologically or cytologically proven non-small cell lung cancer (NSCLC) were treated with ifosfamide in combination with cisplatin and etoposide. Patients received ifosfamide 4 g/m2 with mesna uroprotection on day 1 and cisplatin 25 mg/m2 and etoposide 100 mg/m2 on days 1 through 3. Courses were repeated every 28 days. Premedication with prochlorperazine, dexamethasone, and high-dose metoclopramide was given to prevent nausea, and lorazepam was added on days 2 and 3 only. Seventeen male and three female patients (median age, 57 years) have been treated. Two patients had stage IIIb disease, and 18 had hematogenous metastases. Eighteen patients are evaluable for response and toxicity, and it is too early to evaluate two patients. Early in the study, two patients died of toxicity and have been classified as nonresponders. One patient achieved complete response (21+ weeks), and seven patients achieved partial response (median, 30+ weeks; range, 5 to 38+), for an overall response rate of 44.5%. The median survival of the group has not been reached, and 14 patients are alive 5 to 38+ weeks from the start of treatment. The median nadir granulocyte count was 0.275 x 10(9)/L (range, 0 to 2.283 x 10(9)/L), and there were six episodes (involving 5 patients) of neutropenia-associated fever, one of which resulted in death. The median nadir platelet count was 120 x 10(9)/L (range, 13 to 385 x 10(9)/L), but no patient experienced bleeding or required platelet transfusions. Five patients required RBC transfusions. Only eight patients had grade 2 gastrointestinal toxicity, and one patient had microscopic hematuria; there was no CNS toxicity.

Adult↗
PubMed1989

Differing susceptibilities of platelets from normal individuals and patients with von Willebrand's disease to attack by quinine- and quinidine-dependent antiplatelet antibodies.

Reactivity of quinine- and quinidine-dependent antiplatelet antibodies has been compared in platelet-rich-plasma (PRP) from normal donors and from patients with von Willebrand's disease (vWd). One quinine-dependent antibody (Q.Ab) caused platelet aggregation and [14C] serotonin release with only 7 of 12 normal donors, while another Q.Ab and a quinidine-dependent antibody (Qd.Ab) caused aggregation and release with all 12. Drug-dependent IgG binding and PF 3 availability induced by the antibodies were, however, comparable in all donors. Differences in responsiveness were associated with platelets and not plasma. vWd platelets showed normal drug-dependent IgG binding, but decreased aggregation and serotonin release to most drug-dependent antibodies. Responsiveness was not restored by purified vWf:Ag, but, in one case, was corrected by normal plasma or cryoprecipitate. Drug-dependent binding of the Q.Ab which caused variable responsiveness in normals was to the same platelet antigens (GPIb and GPIIIa) in both normal and vWd platelets and did not require plasma components. Reduced PF 3 availability was seen with some antibodies in some vWd patients. Plasma from two of these patients inhibited aggregation of normal platelets to Q.Ab and one of these inhibited aggregation to ADP. Antiplatelet antibodies were detected in these two plasmas by ELISA. Thus some Q.Ab produce different responses with platelets from different donors. In vWd, reduced responsiveness to Q.Ab and Qd.Ab may result from production of inhibitory antiplatelet antibodies.

Autoantibodies↗
PubMed1988

Heterogeneity of drug-dependent platelet antigens and their antibodies in quinine- and quinidine-induced thrombocytopenia: involvement of glycoproteins Ib, IIb, IIIa, and IX.

The molecular nature of platelet receptors for quinine- and quinidine-dependent antiplatelet antibodies (Q.Ab and Qd.Ab) was studied by immunoblotting. One Q.Ab caused quinine-dependent IgG binding to platelet proteins with molecular weights (mol wts) of 174 Kd and 93 Kd and another to only a 93-Kd protein. A third Q.Ab caused binding to 174-, 140-, 93-, and 57-Kd proteins, while a fourth Q.Ab and a Qd.Ab caused IgG binding to 174- and 18-Kd proteins. Using platelets from patients with Glanzmann's thrombasthenia or Bernard Soulier syndrome and purified GPIIIa, these proteins were shown to be GPIb, GPIIb, GPIIIa, GPIX, and an unidentified 57-Kd protein missing in Bernard Soulier syndrome. Binding to the 93-Kd protein was independent of the PIA1 antigen. Absorption of one Q.Ab with Glanzmann's thrombasthenia platelets revealed different populations of antibodies with different specificities within the one patient. Thus Q.Ab and Qd.Ab are heterogeneous and may be directed toward different epitopes on major platelet glycoproteins.

Antigens, Differentiation↗
PubMed1987

Analysis of immunoglobulins that bind to platelets from serum of patients with immune thrombocytopenia: molecular weight distribution.

The nature of platelet- bindable immunoglobulins (PB-Ig) in serum has been investigated. PB-IgG, -A and -M were measured by an ELISA using platelets coated on microtitre plates. This assay detected alloantibodies at high serum dilutions. In 32 patients with idiopathic thrombocytopenic purpura (ITP) or systemic lupus erythematosus (SLE) raised levels of at least one PB-Ig class were found in 18. To distinguish binding due to immune complexes, the molecular weight of PB-IgG was studied by gel filtration on Sepharose 4B. In sera from patients with ITP and SLE, PB-IgG with Mr of primarily 150 Kd was observed, compatible with monomeric IgG antiplatelet antibodies. Levels of PB-IgG in serum were not related to total serum IgG. In sera from the patients with SLE and some with ITP (most of whom had several of the features of SLE), PB-IgG with Mr of 200 Kd - greater than 1000 Kd was seen. In heat-aggregated preparations of normal IgG, PB-IgG with Mr up to 1000 Kd was also found. Rabbit IgG was able to block PB-IgG in fractions of high molecular weight in purified normal IgG, heat-aggregated normal IgG and in patient serum, but had no effect on the 150 Kd peak. In whole serum from patients who had high molecular weight PB-IgG, the inhibitory effects of rabbit IgG were much less than in isolated high molecular weight column fractions. Thus although the majority of PB-IgG is monomeric antiplatelet antibody, some PB-IgG with higher molecular weight, characteristic of immune complexes, occurs in sera of some patients with autoimmune thrombocytopenia and it makes a small contribution to PB-IgG levels measured in whole serum.

Animals↗