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Biomedical subjects

D Logan

Publications and source records attributed to D Logan.

At least 19 recordsLinked to original sources
PubMed1996

Paclitaxel plus hydroxyurea as second line therapy for non-small cell lung cancer.

We tested paclitaxel (Taxol) and low dose hydroxyurea as second line therapy in 30 patients with non-small cell lung cancer since both drugs are active against non-small cell lung cancer in other settings, and since hydroxyurea may reverse chemotherapy resistance by disrupting double minute chromosomes. Hydroxyurea 500 mg was given orally each Monday, Wednesday, Friday starting 1 week before paclitaxel, and continuing until removal from study. Paclitaxel 135 mg/m2 was given i.v. over > or = 1 h every 3 weeks with dexamethasone, diphenhydramine, and ranitidine. Patients could have paclitaxel doses escalated to 175 mg/m2 in course 2 and to 200 mg/m2 in course 3, where tolerated. Sixteen males and 14 females were treated. All patients had previously received a single cisplatin-based chemotherapy regimen and 23 had previously received radiotherapy. Twelve patients had adenocarcinomas, six had squamous cell carcinomas, and 12 had large cell carcinomas. Eight patients had Stage IIIb cancers and 22 had Stage IV. Paclitaxel doses were 135 mg/m2 in 56 courses, 175 mg/m2 in 24, and 200 mg/m2 in 15. Treatment was well tolerated. Median granulocyte nadirs were 2.5 (x 10(9)/l) for paclitaxel 135 mg/m2, 1.8 for 175 mg/m2, and 1.3 for 200 mg/m2. No patient developed febrile neutropenia, and none required a dose reduction. Two patients had reversible anaphylaxis. Other toxicities were quite tolerable. They included fatigue, myalgias, dizziness, paresthesias, diarrhea, alopecia, mucositis, flushing, headache, swollen red hands, and anxiety. One patient had a partial remission and 15 had stable disease (including six with minor responses). Median survival was 20 (95% CI, 12-34) weeks, with 19% of patients remaining alive at 1 year from initiation of treatment. This is a well-tolerated regimen with modest activity as second line chemotherapy for patients with non-small cell lung cancer previously treated with cisplatin regimens. Higher doses would be feasible and other strategies are now being explored.

Aged↗
PubMed1995

Structural comparison of two strains of foot-and-mouth disease virus subtype O1 and a laboratory antigenic variant, G67.

BACKGROUND: Foot-and-mouth disease viruses (FMDVs) are members of the picornavirus family and cause an economically important disease of cloven-hoofed animals. To understand the structural basis of antigenic variation in FMDV, we have determined the structures of two viruses closely related to strain O1BFS whose structure is known. RESULTS: The two new structure are, like O1BFS, both serotype O viruses. The first, O1 Kaüfbeuren (O1K), is a field isolate dating from an outbreak of FMD in Europe in the 1960s. The second, called G67, is a quadruple mutant of O1K, generated in the laboratory, that bears point mutations conferring resistance to neutralizing by monoclonal antibodies, specific for each of the four major antigenic sites defined previously. The availability of the three related virus structures permits a detailed analysis of the way amino acid substitutions influence antigenicity. Structural changes are seen to be limited, in general, to the substituted side chain. For example, the GH loop of VP1, a highly antigenic and mobile protuberance which becomes ordered only under reducing conditions, was essentially indistinguishable in the three viruses despite the accumulation of up to four changes within its 15-residue sequence. At one of the other antigenic sites, however, changes between the two field strains did perturb both side-chain and main-chain structures in the vicinity. CONCLUSIONS: The conservation of conformation of the GH loop of VP1 adds to the evidence implicating an integrin as the cellular receptor for FMDV, since this loop contains a conserved RGD (Arg-Gly-Asp) sequence structurally similar to the same tripeptide in some other integrin-binding proteins. Structural changes required for the virus to escape neutralization by monoclonal antibodies are generally small. The more extensive type of structural change exhibited by the field isolates probably reflects differing selective pressures operating in vivo and in vitro.

Amino Acid Sequence↗
PubMed1994

The structure of an immunodominant loop on foot and mouth disease virus, serotype O1, determined under reducing conditions.

Residues 136-159 of VPI of foot and mouth disease virus (FMDV) comprise the G-H loop of the protein and form a prominent feature on the surface of virus particles. This sequence contains an immunodominant neutralizing epitope, which can be mimicked with synthetic peptides, and includes an Arg, Gly, Asp motif which has been implicated in the binding of the virus to cellular receptors. Crystallographic analysis of native virus particles failed to resolve the structure of this region due to its disordered state. However, reduction of a disulphide bond between cysteine residues 134 of VP1 and 130 of VP2 caused the G-H loop to collapse onto the surface of the virus particle and allowed its conformation to be determined.

Amino Acid Sequence↗
PubMed1994

VP-16, ifosfamide and cisplatin (VIP) for extensive small cell lung cancer.

Thirty-seven extensive disease SCLC patients were treated with ifosfamide 1.0 g/m2 (maximum 1.75 g), VP-16 (etoposide) 75 mg/m2 and cisplatin 20 mg/m2 (VIP) daily for 5 days in hospital. Mesna was given as a continuous infusion until 12 h after the last ifosfamide dose. Treatment was reduced to 4 days after the first 8 patients experienced serious myelotoxicity. 30 patients were evaluable for response. 8 (27%) achieved a complete response and 60% had a partial response. The median duration of response was 23 weeks. The median survival of all 37 patients was 41 weeks, and 47 weeks for the 30 evaluable patients. Fifty per cent and 26% of the evaluable treatment courses were associated with grade 4 and 3 granulocytopenia, respectively. There were eight febrile events including four treatment-related deaths from sepsis on the 5-day regimen. Although the response to VIP was generally rapid, the proportion achieving complete response (27% of evaluable patients) and the median survival is similar to standard chemotherapy regimens which are less toxic and less complex to administer.

Adult↗
PubMed1994

Addition of pentoxifylline plus nifedipine to chemotherapy in patients with cisplatin-resistant cancers of the lung and other sites.

Eight evaluable patients with cisplatin-resistant non-small cell lung cancer (6 patients), small cell lung cancer (1 patient), or both breast and ovarian cancer (1 patient) were entered on a study to determine whether the addition of nifedipine plus pentoxifylline to cisplatin-based chemotherapy would result in increased chemotherapy efficacy. No patient responded to treatment. Myelosuppression may have been augmented by the nifedipine and pentoxifylline (median granulocyte nadir, 0.3 x 10(9)/L). Two patients developed febrile neutropenia. Nifedipine and pentoxifylline had to be stopped in two evaluable patients due to hypotension, and three additional inevaluable patients withdrew from the study due to nifedipine-pentoxifylline toxicity before receiving their chemotherapy. There was no indication that other types of chemotherapy toxicity were increased by the addition of nifedipine and pentoxifylline. A major problem with the strategy followed in this protocol was that patients whose tumors had failed to respond to cisplatin-based regimens were often too ill to tolerate additional cisplatin, particularly when accompanied by nifedipine-associated hypotension.

Antineoplastic Combined Chemotherapy Protocols↗
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↗