Low-frequency and rare exome chip variants associate with fasting glucose and type 2 diabetes susceptibility

Fasting glucose and insulin are intermediate traits for type 2 diabetes. Here we explore the role of coding variation on these traits by analysis of variants on the HumanExome BeadChip in 60,564 non-diabetic individuals and in 16,491 T2D cases and 81,877 controls. We identify a novel association of a low-frequency nonsynonymous SNV in GLP1R (A316T; rs10305492; MAF=1.4%) with lower FG (β=-0.09±0.01 mmol l(-1), P=3.4 × 10(-12)), T2D risk (OR[95%CI]=0.86[0.76-0.96], P=0.010), early insulin secretion (β=-0.07±0.035 pmolinsulin mmolglucose(-1), P=0.048), but higher 2-h glucose (β=0.16±0.05 mmol l(-1), P=4.3 × 10(-4)). We identify a gene-based association with FG at G6PC2 (pSKAT=6.8 × 10(-6)) driven by four rare protein-coding SNVs (H177Y, Y207S, R283X and S324P). We identify rs651007 (MAF=20%) in the first intron of ABO at the putative promoter of an antisense lncRNA, associating with higher FG (β=0.02±0.004 mmol l(-1), P=1.3 × 10(-8)). Our approach identifies novel coding variant associations and extends the allelic spectrum of variation underlying diabetes-related quantitative traits and T2D susceptibility.

Pairwise interactions between linear alkanes in water measured by AFM force spectroscopy

Pairwise interactions between n-alkanes from decane to octadecane in water have been studied by single-molecule force spectroscopy. The interacting molecules are covalently tethered to the glass substrate and to the probe of an atomic force microscope by water-soluble linkers to facilitate single-molecule detection. However, the measured distribution of rupture forces deviates significantly from the distribution predicted by theoretical models for rupture of individual bonds. To describe the statistics of rupture forces, an analytical model that considers near-simultaneous rupture of two bonds loaded by tethers with different lengths is introduced. The common most probable force analysis approach is used for comparison. In both data analyses, the possible systematic errors due to nonlinear elasticity of polymeric tethers and variations in the shape of the potential of mean force were considered. Experimental distributions of rupture forces are well-fit by the two-bond rupture model using a single set of kinetic parameters for different experiments, while the most probable force approach yields parameters that vary significantly for different samples. The measured activation energies for dissociation of alkanes are close to the free energies predicted by cavity models of hydrophobic interactions. The surface free-energy density is estimated to be approximately 21 kJ/(mol nm (2)) and is close to the upper limit of free energies used in the computer simulations of hydrophobic interactions in proteins. In contrast to the predictions of the cavity models, the measured activation energy does not increase monotonically with increase in alkane chain size. To explain this discrepancy and the measured distance to the transition-state barrier (approximately 0.6 nm), it is suggested that alkanes undergo conformational transition to the collapsed state upon dimerization. Change in the alkane conformation from extended to helical has been observed previously for binding of alkanes in water to hydrophobic synthetic receptors. Here, however, conformational change is suggested without geometrical constraints imposed by small cavitands. The proposed collapsed state of the alkane dimers has implications for the kinetics of self-assembly of surfactant micelles.

Investigation of a tuberculosis cluster at a job centre in Manchester, United Kingdom

During the summer of 2005, four cases of active tuberculosis from the same occupational setting were investigated in Manchester, UK. The index case had been diagnosed in December of the previous year. At that stage the closest occupational contacts had been screened, all of whom were assessed as being free from active disease, and none had met nationally recommended criteria for chemoprophylaxis for latent tuberculosis infection (LTBI). In June 2005, two work contacts developed progressive primary extrapulmonary (pleural) TB. Following a detailed risk assessment, the screening programme was widened to include 137 staff who worked at the job centre (employment agency) where the first four cases had been found. This screening programme was based on tuberculin Mantoux testing, CXR and gamma-interferon testing. Of these 137 contacts screened, one additional person was found to have active disease and six others were offered chemoprophylaxis for LTBI. The isolates from the index case and the first two secondary cases were indistinguishable on VNTR-MIRU (variable number tandem repeat - mycobacterial interspersed repetitive unit) typing at 15 loci. No samples were available for testing from the fourth case of active disease. Management of this incident has benefited from the evolving fields of both genotyping and diagnostic testing for LTBI. However, further research into the epidemiological inferences made through genotyping, as well as the significance of a positive gamma-interferon test in assessing the risk of development of active disease, is still required.

Reducing the risks of transmitting gastrointestinal infections in home paddling pools

The human health risks posed by natural and man-made water environments through contamination with either human or animal faeces was recently been highlighted in an editorial

Investigation of a tuberculosis cluster at a job centre in Manchester, United Kingdom

During the summer of 2005, four cases of active tuberculosis from the same occupational setting were investigated in Manchester, UK. The index case had been diagnosed in December of the previous year. At that stage the closest occupational contacts had been screened, all of whom were assessed as being free from active disease, and none had met nationally recommended criteria for chemoprophylaxis for latent tuberculosis infection (LTBI). In June 2005, two work contacts developed progressive primary extrapulmonary (pleural) TB. Following a detailed risk assessment, the screening programme was widened to include 137 staff who worked at the job centre (employment agency) where the first four cases had been found. This screening programme was based on tuberculin Mantoux testing, CXR and gamma-interferon testing. Of these 137 contacts screened, one additional person was found to have active disease and six others were offered chemoprophylaxis for LTBI. The isolates from the index case and the first two secondary cases were indistinguishable on VNTR-MIRU (variable number tandem repeat--mycobacterial interspersed repetitive unit) typing at 15 loci. No samples were available for testing from the fourth case of active disease. Management of this incident has benefited from the evolving fields of both genotyping and diagnostic testing for LTBI. However, further research into the epidemiological inferences made through genotyping, as well as the significance of a positive gamma-interferon test in assessing the risk of development of active disease, is still required.

Doxorubicin and cisplatin chemotherapy in high-grade spindle cell sarcomas of the bone, other than osteosarcoma or malignant fibrous histiocytoma: a European Osteosarcoma Intergroup Study

There are limited data that define the role of chemotherapy in the treatment of high-grade spindle cell sarcomas of bone, other than osteosarcoma or malignant fibrous histiocytoma (MFH-B). This prospective study evaluates the effect of doxorubicin and cisplatin on these tumours. Thirty-seven patients, age 65 years, with spindle cell sarcoma of bone, except osteosarcoma or MFH-B, were included. Chemotherapy consisted of doxorubicin and cisplatin every 3 weeks for six cycles. Resection was performed after three cycles. In 15 patients with metastases, response assessment showed three complete responses (CR), four stable disease (SD), five progression; three were not evaluable. Median time to progression was 30 months (95% Confidence Interval (CI), 8-51 months) for the operable non-metastatic patients; median survival 41 months (95% CI, 16-82 months). Median time to progression in the metastatic group was 10 months (95% CI, 0-18 months) and median survival was 14 months (95% CI, 4-45 months). This study suggests a limited role for doxorubicin and cisplatin in metastatic high-grade spindle cell sarcoma of bone, other than osteosarcoma or MFH-B cases.

TNFα polymorphism frequencies in HPV-associated cervical dysplasia

OBJECTIVES

Persistent high-risk HPV infection of the uterine cervix is associated with CIN and cervical carcinoma. Women with a reduced pro-inflammatory response to HPV are likely to be susceptible to viral persistence, and therefore, potentially more vulnerable to cervical neoplasia. In this study, we investigate whether nucleotide sequence polymorphisms in the TNFalpha (TNFSF2) gene (which can modify gene transcription up to 9-fold) might influence susceptibility to, or evolution of, CIN.

METHODS

Induced heteroduplex analysis was used to identify polymorphisms at positions TNFalpha -308 and -238 in women with normal cervical cytology and with cervical disease. Patients with low-grade disease were HPV typed using general primer GP5+/6+ PCR/EIA and reverse line blotting, and were reassessed for disease status at 6 and 24 months.

RESULTS

CIN patients as a group had a significantly higher frequency of TNFalpha -308 low-secretor genotypes (GG) compared to controls, and this effect was most pronounced in the CIN1 group (P = 0.01 and P = 0.004, respectively). TNFalpha polymorphism frequencies at position -238 were similar for patients and controls. Neither polymorphism was associated with the presence of HPV infection at recruitment or disease outcome at 6 or 24 months.

CONCLUSIONS

These findings support the hypothesis that susceptibility to CIN is influenced by TNFalpha -308 polymorphism.

Sequence requirements for the activity of membrane-active peptides

Synthetic peptides were constructed with the sequence of the first 20 residues of melittin and terminating with a range of different amino acid amides. These were found to have haemolytic and cytolytic activity similar to that of melittin, provided that certain charge constraints were observed. The nature of the 21st residue was not critical except when the residue introduced a negative charge. The presence of at least two positive charges in the molecule was found to be essential for activity. One of these charges could be the amino-terminal amine. Peptides could be inactivated by the addition of a non-acidic presequence which was acetylated at the N-terminus. Introducing a protease cleavable sequence into an N-terminal extension of the peptides produced analogues with low haemolytic activity that could be activated by proteolytic action. A peptide with extra positive charges introduced on the hydrophilic face of the helix possessed a haemolytic activity that was greater than that of melittin.

A prospective regional audit of surgical management of endometrial cancer in the South and West of England

The results of a prospective audit of surgical management of endometrial cancer in the South and West of England is presented. A minimum data set was defined and information collected prospectively. There was limited tertiary referral to a gynaecological oncologist. The role of centralisation of endometrial cancer care has been questioned, as surgery has traditionally been simple in patients perceived to be at increased risk of more radical surgery. However, this audit demonstrates that standards of even this simple care within the region are often inadequate, with only one-third of patients having basic staging procedures performed fully. This has important implications for patients management, future interpretation of outcome data and clinical governance in endometrial cancer care.

A randomised phase II study on neo-adjuvant chemotherapy for 'high-risk' adult soft-tissue sarcoma

The aim of this study was to examine the strategy, feasibility and outcome of neo-adjuvant chemotherapy, with doxorubicin and ifosfamide, in adult patients with 'high-risk' soft-tissue sarcomas. Patients with 'high-risk' soft-tissue sarcomas, defined as tumours > or =8 cm of any grade, or grade II/III tumours <8 cm, or grade II/III locally recurrent tumours, or grade II/III tumours with inadequate surgery performed in the previous 6 weeks and therefore requiring further surgery, were randomised between either surgery alone or three cycles of 3-weekly doxorubicin 50 mg/m(2) intravenous (i.v.) bolus and ifosfamide 5 g/m(2) (24 h infusion) before surgery. The type of surgery had to be planned at randomisation. Tumours were to be amenable to surgery by amputation, compartmental resection, wide or marginal excision. If chemotherapy was given, surgery had to be performed within 21 days after the last chemotherapy. Patients received postoperative radiotherapy in cases of marginal surgery, microscopically incomplete resection and no further possibility for surgery, and in cases of surgery because of local recurrence. 150 patients were entered into the study and 134 were eligible, 67 in each arm. The most frequent side-effects of chemotherapy were alopecia, nausea and vomiting (95%), and leucocytopenia (32%). One patient died of neutropenic fever after the first cycle of chemotherapy. Chemotherapy did not interfere with planned surgery and did not affect postoperative wound healing. Limb-salvage was achieved in 88%, amputation was necessary in 12% (all according to the plan at randomisation). The trial was closed after completion of phase II, since accrual was too slow to justify expanding the study into the scheduled phase III study. At a median follow-up of 7.3 years, the 5 year disease-free survival is estimated at 52% for the no chemotherapy and 56% for the chemotherapy arm (standard error: 7%) (P=0.3548). The 5 year overall survival for both arms is 64 and 65%, respectively (standard error 7%) (P=0.2204). Neo-adjuvant-chemotherapy with doxorubicin and ifosfamide at these doses and with this schedule was feasible and did not compromise subsequent treatment, surgery with or without radiotherapy. Although not powered to draw definitive conclusions on benefit, but with an at least 7 year median follow-up, the results render it less likely that major survival benefits will be achieved with this type of chemotherapy.

Amino acid propensities for the collagen triple-helix

Determination of the tendencies of amino acids to form alpha-helical and beta-sheet structures has been important in clarifying stabilizing interactions, protein design, and the protein folding problem. In this study, we have determined for the first time a complete scale of amino acid propensities for another important protein motif: the collagen triple-helix conformation with its Gly-X-Y repeating sequence. Guest triplets of the form Gly-X-Hyp and Gly-Pro-Y are used to quantitate the conformational propensities of all 20 amino acids for the X and Y positions in the context of a (Gly-Pro-Hyp)(8) host peptide. The rankings for both the X and Y positions show the highly stabilizing nature of imino acids and the destabilizing effects of Gly and aromatic residues. Many residues show differing propensities in the X versus Y position, related to the nonequivalence of these positions in terms of interchain interactions and solvent exposure. The propensity of amino acids to adopt a polyproline II-like conformation plays a role in their triple-helix rankings, as shown by a moderate correlation of triple-helix propensity with frequency of occurrence in polyproline II-like regions. The high propensity of ionizable residues in the X position suggests the importance of interchain hydrogen bonding directly or through water to backbone carbonyls or hydroxyprolines. The low propensity of side chains with branching at the C(delta) in the Y position supports models suggesting these groups block solvent access to backbone C=O groups. These data provide a first step in defining sequence-dependent variations in local triple-helix stability and binding, and are important for a general understanding of side chain interactions in all proteins.

Treatment of brain metastases of small-cell lung cancer: comparing teniposide and teniposide with whole-brain radiotherapy--a phase III study of the European Organization for the Research and Treatment of Cancer Lung Cancer Cooperative Group

PURPOSE

Approximately 60% of patients with small-cell lung cancer (SCLC) develop brain metastases. Whole-brain radiotherapy (WBRT) gives symptomatic improvement in more than 50% of these patients. Because brain metastases are a sign of systemic progression, and chemotherapy was found to be effective as well, it becomes questionable whether WBRT is the only appropriate therapy in this situation.

PATIENTS AND METHODS

In a phase III study, SCLC patients with brain metastases were randomized to receive teniposide with or without WBRT. Teniposide 120 mg/m(2) was given intravenously three times a week, every 3 weeks. WBRT (10 fractions of 3 Gy) had to start within 3 weeks from the start of chemotherapy. Response was measured clinically and by computed tomography of the brain.

RESULTS

One hundred twenty eligible patients were randomized. A 57% response rate was seen in the combined-modality arm (95% confidence interval [CI], 43% to 69%), and a 22% response rate was seen in the teniposide-alone arm (95% CI, 12% to 34%) (P<.001). Time to progression in the brain was longer in the combined-modality group (P=.005). Clinical response and response outside the brain were not different. The median survival time was 3.5 months in the combined-modality arm and 3.2 months in the teniposide-alone arm. Overall survival in both groups was not different (P=.087).

CONCLUSION

Adding WBRT to teniposide results in a much higher response rate of brain metastases and in a longer time to progression of brain metastases than teniposide alone. Survival was poor in both groups and not significantly different.

Randomized Trial of Surgery Versus Radiotherapy in Patients with Stage IIIA (N2) Non–Small-Cell Lung Cancer After a Response to Induction Chemotherapy: EORTC 08941

Combined modality treatment of patients with stage III non small-cell lung cancer (NSCLC) has recently become widely accepted. Standard combinations are neoadjuvant chemotherapy followed by radiotherapy or concurrent chemotherapy and radiotherapy. The effect of combined modality treatment on survival is dependent on both the efficacy of chemotherapy to eradicate micrometastases and optimal local control. The European Organization for Research and Treatment of Cancer (EORTC) Lung Cancer Cooperative Group has chosen to investigate in a comparative way the side effects and the effect on survival of radiotherapy versus surgery in stage IIIA (N2) NSCLC.

Destabilization of osteogenesis imperfecta collagen-like model peptides correlates with the identity of the residue replacing glycine

Mutations resulting in replacement of one obligate Gly residue within the repeating (Gly-Xaa-Yaa)(n) triplet pattern of the collagen type I triple helix are the major cause of osteogenesis imperfecta (OI). Phenotypes of OI involve fragile bones and range from mild to perinatal lethal. In this study, host-guest triple-helical peptides of the form acetyl-(Gly-Pro-Hyp)(3)-Zaa-Pro-Hyp-(Gly-Pro-Hyp)(4)-Gly-Gly-amide are used to isolate the influence of the residue replacing Gly on triple-helix stability, with Zaa = Gly, Ala, Arg, Asp, Glu, Cys, Ser, or Val. Any substitution for Zaa = Gly (melting temperature, T(m) = 45 degrees C) results in a dramatic destabilization of the triple helix. For Ala and Ser, T(m) decreases to approximately 10 degrees C, and for the Arg-, Val-, Glu-, and Asp-containing peptides, T(m) < 0 degrees C. A Gly --> Cys replacement results in T(m) < 0 degrees C under reducing conditions but shows a broad transition (T(m) approximately 19 degrees C) in an oxidizing environment. Addition of trimethylamine N-oxide increases T(m) by approximately 5 degrees C per 1 M trimethylamine N-oxide, resulting in stable triple-helix formation for all peptides and allowing comparison of relative stabilities. The order of disruption of different Gly replacements in these peptides can be represented as Ala </= Ser < CPO(red) < Arg < Val < Glu </= Asp. The rank of destabilization of substitutions for Gly in these Gly-Pro-Hyp-rich homotrimeric peptides shows a significant correlation with the severity of natural OI mutations in the alpha1 chain of type I collagen.

The surgical management of cervical carcinoma within the South West of England: progress through an audit loop. Gynaecology Tumour Panel

OBJECTIVE

To define and use a minimum clinical dataset for prospective data collection in order to audit the surgical management of cervical cancer in the South West of England. To compare this data set with a retrospective audit allowing assessment of the quality of care offered to patients.

DESIGN

Prospective collection of a defined dataset on paper forms which were put into a computerised database for analysis. Registrations validated against histopathology databases and hospital coding.

SETTING

All 13 hospitals in the South West of England which participated in the retrospective audit.

PARTICIPANTS

One hundred and sixty-five women with cervical cancer diagnosed in 1997.

MAIN OUTCOME MEASURES

Distribution of cases by hospital and surgeon; workload of individual surgeons; adequacy and accuracy of FIGO staging; adequacy of histological information; and adequacy of surgery.

RESULTS

There is a trend to centralisation of cancer care and radical surgery in the region. Prospective collection of data has dramatically improved FIGO staging with 92% of all cases staged. For cases greater than Stage Ia, 98% were staged suggesting that a target of 100% staging is feasible. The histological dimensions of tumours were not measured in a high proportion of cases (20% of tumour diameters and 28% of tumour thicknesses). Apparent inadequacies in surgical management are explored. In 10/165 cases (6%) inappropriate conservative surgery may have been unavoidable, suggesting that a quality standard of 95% for appropriate radical surgical management of cervical cancer can be achieved. An anatomically complete removal of pelvic node-bearing tissue, yielding greater than 10 nodes in more than 95% cases, should be achievable with each surgeon/pathologist achieving a mean of more than 20 nodes.

CONCLUSION

Regional audit of cervical cancer management is feasible. It can be used to improve the quality of information on management and guide improved service provision.

A phase II study of cisplatin, ifosfamide and doxorubicin in operable primary, axial skeletal and metastatic osteosarcoma. European Osteosarcoma Intergroup (EOI)

BACKGROUND

Despite advances in the treatment of primary limb osteosarcoma, the outcome of patients with primary metastatic and axial skeletal disease remains poor. The European Osteosarcoma Intergroup have assessed a combination chemotherapy regimen consisting of ifosfamide (IFOS) 3 g/m2/dl-2, doxorubicin (DOX) 25 mg/m2/dl-3 i.v. bolus and cisplatin (CDDP) 100 mg/m2/dl.

PATIENTS AND METHODS

One hundred nine previously untreated patients with primary osteosarcoma were registered. Eligibility was confirmed in 103. At presentation, 45 eligible patients had metastatic disease, 15 axial skeletal primary tumours and 43 non-metastatic limb tumours.

RESULTS

The major toxicities were myelosuppression (90%, grade 3 or 4) and nausea and vomiting (74%, grade 3 or 4). Overall mean relative dose intensity (RDI) was 80% (88% CDDP, 75% IFOS, 81% DOX). Clinical response as measured by reduction in tumour volume occurred in 36% (95% confidence interval (95% CI): 27%-47%) of primary tumours. Response of pulmonary metastases to chemotherapy was seen in 33% (95% CI: 19%-49%). Good histological response (> or = 90% necrosis of the tumour) occurred in 33% (95% CI: 22%-45%) of resected tumours. Five-year survival was 62% in limb-non-metastatic, 41% in axial skeletal and 16% in limb metastatic patients.

CONCLUSIONS

This regimen is active in osteosarcoma but does not appear to be more active than the two-drug CDDP-DOX regimen currently recommended by EOI.

The interactions of the N-terminal fusogenic peptide of HIV-1 gp41 with neutral phospholipids

We have studied the interactions with neutral phospholipid bilayers of FPI, the 23-residue fusogenic N-terminal peptide of the HIV-1LAI transmembrane glycoprotein gp41, by CD, EPR, NMR, and solid state NMR (SSNMR) with the objective of understanding how it lyses and fuses cells. Using small unilamellar vesicles made from egg yolk phoshatidylcholine which were not fused or permeabilised by the peptide we obtained results suggesting that it was capable of inserting as an alpha-helix into neutral phospholipid bilayers but was only completely monomeric at peptide/lipid (P/L) ratios of 1/2000 or lower. Above this value, mixed populations of monomeric and multimeric forms were found with the proportion of multimer increasing proportionally to P/L, as calculated from studies on the interaction between the peptide and spin-labelled phospholipid. The CD data indicated that, at P/L between 1/200 and 1/100, approximately 68% of the peptide appeared to be in alpha-helical form. When P/L = 1/25 the alpha-helical content had decreased to 41%. Measurement at a P/L of 1/100 of the spin lattice relaxation effect on the 13C nuclei of the phospholipid acyl chains of an N-terminal spin label attached to the peptide showed that most of the peptide N-termini were located in the interior hydrocarbon region of the membrane. SSNMR on multilayers of ditetradecylphosphatidyl choline at P/Ls of 1/10, 1/20 and 1/30 showed that the peptide formed multimers that affected the motion of the lipid chains and disrupted the lipid alignment. We suggest that these aggregates may be relevant to the membrane-fusing and lytic activities of FPI and that they are worthy of further study.

Structural consequences of D-amino acids in collagen triple-helical peptides

The effects of racemization of aspartic acid on triple-helical formation have been studied using a "host-guest" peptide approach where selected guest Gly-Xaa-Yaa triplets were included within a common acetyl-(Gly-Pro-Hyp)3-Gly-Xaa-Yaa-(Gly-Pro-Hyp)4-Gly-Gly-amide frame-work. Four guest triplets, Gly-Asp-Hyp and Gly-Asp-Ala where Asp is either L-Asp or D-Asp were studied. Thermal stability data indicated that incorporation of D-Asp residues prevented triple-helix formation in phosphate buffered saline, although triple-helical structures were formed in a stabilizing solvent, 67% aqueous ethylene glycol. In this solvent the melting temperatures of D-Asp containing peptides were more than 30 degrees C lower than the corresponding peptides containing L-Asp. For Gly-Asp-Ala peptides, but not Gly-Asp-Hyp, peptides, melting profiles indicated that a mixture of the D- and L-Asp containing peptides were able to form heterotrimer triple-helical molecules. These studies illustrate the dramatic destabilizing effect of D-amino acids on the triple-helix stability, but indicate that they can be accommodated in this conformation.

Inhibition of membrane-active peptides by fatty acid-peptide hybrids

Nine fatty acid-peptide hybrid molecules were constructed using the general formula CH3(CH2)nCO-Phe Asp Cys-amide and tested for their ability to inhibit cell lysis induced by the membrane-active peptide melittin. All of these molecules, where n = 4-14, inhibited the action of melittin to some extent, but the longer carbon chains were most effective. Several potential inhibitors were also constructed with conservative substitutions in the peptide portion of the molecule. All were effective to varying degrees. We concluded that in the hexapeptide inhibitor published by Blondelle et al. (1993), the role of the first three residues is only to provide hydrophobic interaction with the melittin and has no particular amino acid sequence specificity. Some of these inhibitors were found to inhibit the lytic activity of a melittin analogue which had only superficial sequence similarity to melittin and also a truncated form of melittin, indicating the generality of the action of the inhibitors.

High-dose epirubicin is not an alternative to standard-dose doxorubicin in the treatment of advanced soft tissue sarcomas. A study of the EORTC soft tissue and bone sarcoma group

The activity and toxicity of single-agent standard-dose doxorubicin were compared with that of two schedules of high-dose epirubicin. A total of 334 chemonaive patients with histologically confirmed advanced soft-tissue sarcomas received (A) doxorubicin 75 mg m(-2) on day 1 (112 patients), (B) epirubicin 150 mg m(-2) on day 1 (111 patients) or (C) epirubicin 50 mg m(-2) day(-1) on days 1, 2 and 3 (111 patients); all given as bolus injection at 3-week intervals. A median of four treatment cycles was given. Median age was 52 years (19-70 years) and performance score 1 (0-2). Of 314 evaluable patients, 45 (14%) had an objective tumour response (eight complete response, 35 partial response). There were no differences among the three groups. Median time to progression for groups A, B and C was 16, 14 and 12 weeks, and median survival 45, 47 and 45 weeks respectively. Neither progression-free (P = 0.93) nor overall survival (P = 0.89) differed among the three groups. After the first cycle of therapy, two patients died of infection and one owing to cardiovascular disease, all on epirubicin. Both dose schedules of epirubicin were more myelotoxic than doxorubicin. Cardiotoxicity (> or = grade 3) occurred in 1%, 0% and 2% respectively. Regardless of the schedule, high-dose epirubicin is not a preferred alternative to standard-dose doxorubicin in the treatment of patients with advanced soft-tissue sarcomas.

Efficacy of fusion peptide homologs in blocking cell lysis and HIV-induced fusion

Contrary to earlier reports, we have found that tri- and hexapeptides analogous or homologous with segments of the 23-residue N-terminal fusion sequence (FS) of the viral transmembrane glycoprotein gp41 (residues 517-539) did not significantly inhibit HIV-1-induced syncytium formation, using an uninfected cell-infected cell fusion assay. In contrast, we found that the high molecular weight apolipoprotein A-1 and a 23-residue analog of the FS, with the phenylalanine residues at positions 524 and 527 replaced with alanine residues, were effective inhibitors. Although the tripeptides were ineffective as inhibitors of syncytium formation, we found a number of them inhibited red cell lysis induced by the synthetic peptide AVGIGALFLGFLGAAGSTMGARS (based on the HIV-1 gp41 FS). This effect was also seen with apolipoprotein A-1. The Ala524,527 analog of the fusion sequence could not be tested in this system because it was hemolytic. We concluded that the smaller peptides were effective inhibitors of hemolysis because they interfered with pore formation by the fusion sequence peptide, either by disrupting the pores or by preventing the peptide from adopting the alpha-helical conformation found in the pores. On the other hand, membrane fusion, which is a prelude to syncytium formation, has been shown to require the fusion sequence in the beta-strand conformation. We argue that small peptides would be unable to block interaction between such strands, although larger molecules, such as apolipoprotein A-1 and the Ala524,527 analog, would be able to do so and thus inhibit fusion. It seems, therefore, that a successful drug directed against the FS-cell membrane interaction stage of syncytium formation would need to be of relatively high molecular weight and complexity.

Brain-only metastases of small cell lung cancer; efficacy of whole brain radiotherapy. An EORTC phase II study

BACKGROUND AND PURPOSE

To evaluate the efficacy of WBRT as a single treatment modality in patients with brain metastases of small cell lung cancer.

PATIENTS AND METHODS

The patients had brain metastases of small cell lung cancer without any sign of tumour outside the brain and were treated with 10 x 3.0 Gy WBRT. Response and neurological functions were evaluated after 6, 18 and 36 weeks.

RESULTS

Twenty of 22 eligible patients were evaluable for response. In six patients a complete response was seen and in five patients a partial response was seen giving a response rate of 50% (95% CI 28-72%). Response duration was 5.4 months (range 63-260 days) and median survival was 4.7 months (range 14-743 days). In the majority of patients the first site of progression after WBRT was in the central nervous system. Twelve of the patients had stabilization or improvement of the neurological function.

CONCLUSION

WBRT for brain metastases of small cell lung cancer gives a 50% response rate with stabilization or improvement of neurological function. Response duration and survival are short.

Positional preferences of ionizable residues in Gly-X-Y triplets of the collagen triple-helix

Collagens contain a high amount of charged residues involved in triple-helix stability, fibril formation, and ligand binding. The contribution of charged residues to stability was analyzed utilizing a host-guest peptide system with a single Gly-X-Y triplet embedded within Ac(Gly-Pro-Hyp)3-Gly-X-Y-(Gly-Pro-Hyp)4-Gly-Gly-NH2. The ionizable residues Arg, Lys, Glu, and Asp were incorporated into the X position of Gly-X-Hyp; in the Y position of Gly-Pro-Y; or as pairs of oppositely charged residues occupying X and Y positions. The Gly-X-Hyp peptides had similar thermal stabilities, only marginally less stable than Gly-Pro-Hyp, whereas Gly-Pro-Y peptides showed a wide thermal stability range (Tm = 30-45 degrees C). The stability of peptides with oppositely charged residues in the X and Y positions appears to reflect simple additivity of the individual residues, except when X is occupied by a basic residue and Y = Asp. The side chains of Glu, Lys, and Arg have the potential to form hydrogen bonds with available peptide backbone carbonyl groups within the triple-helix, whereas the shorter Asp side chain does not. This may relate to the unique involvement of Asp residues in energetically favorable ion pair formation. These studies clarify the dependence of triple-helix stability on the identity, position, and ionization state of charged residues.

Gly-Pro-Arg confers stability similar to Gly-Pro-Hyp in the collagen triple-helix of host-guest peptides

A set of host-guest peptides of the form Ac(Gly-Pro-Hyp)3-Gly-X-Y-(Gly-Pro-Hyp)4-Gly-Gly-NH2 has been designed to evaluate the propensity of different Gly-X-Y triplets for the triple-helix conformation (Shah, N. K., Ramshaw, J. A. M., Kirkpatrick, A., Shah, C., and Brodsky, B. (1996) Biochemistry 35, 10262-10268). All Gly-X-Y guest triplets led to a decrease in melting temperature from the host (Gly-Pro-Hyp)8 peptide except for Gly-Pro-Arg. In this Gly-Pro-Hyp-rich environment, Gly-Pro-Arg was found to be as stabilizing as Gly-Pro-Hyp. Decreased stability of host-guest peptides containing Gly-Pro-Lys, Gly-Pro-homo-Arg, and Gly-Arg-Hyp compared with Gly-Pro-Arg indicated a stabilization that is optimal for Arg and specific to the Y-position. Arg was found to have a similar stabilizing effect when residues other than Pro are in the X-position. Both Arg and Hyp stabilize the triple-helix preferentially in the Y-position in a stereospecific manner and occupy largely Y-positions in collagen. However, contiguous Gly-Pro-Hyp units are highly stable and promote triple-helix folding, whereas incorporation of multiple Gly-Pro-Arg triplets was destabilizing and folded slowly due to charge repulsion. In collagen, Gly-Pro-Arg may contribute maximally to local triple-helix stability while also having the potential for electrostatic interactions in fibril formation and binding.

Etoposide in malignant pleural mesothelioma: two phase II trials of the EORTC Lung Cancer Cooperative Group

Intravenous and oral etoposide (VP 16-213) were tested in two sequential phase II trials in chemotherapy-naive patients with malignant pleural mesothelioma. In the first trial, etoposide was given intravenously (i.v.) at a dose of 150 mg/m2 on days 1, 3 and 5 every 3 weeks. The second trial investigated a daily oral dose of 100 mg for 21 days followed by a 2-week treatment-free period, and then recycling. In both trials, the treatment was given until disease progression, intolerable toxicity or patient refusal. In the i.v. trial, 49 patients were included, 2 patients were ineligible. The oral trial recruited 45 patients, 4 patients were not eligible. In both trials, the main side-effects were moderate leucopenia, alopecia, nausea and vomiting. Two partial responses (4%) and three partial responses (7%) were reported in the i.v. and oral trials, respectively. The median survival was 29 weeks and 38 weeks in the i.v. and oral trials, respectively. In conclusion, further investigation of etoposide in malignant mesothelioma is not recommended.

Role of recombinant interferon-gamma maintenance in responding patients with small cell lung cancer. A randomised phase III study of the EORTC Lung Cancer Cooperative Group

This study was undertaken to determine if recombinant interferon-gamma (rIFN-gamma) given every other day as maintenance therapy could prolong the survival of patients with small cell lung cancer (SCLC) who achieved a complete or nearly-complete response to induction therapy. A secondary endpoint was to assess the toxicity of alternate day doses of this treatment. One hundred and seventy seven patients in complete or nearly-complete response following chemotherapy with or without thoracic radiotherapy were studied. Patients were randomised to receive either rIFN-gamma 4 million units (0.2 mg) subcutaneously every other day for 4 months or observation. One hundred and twenty of the 127 registered patients were eligible; 59 patients received IFN and 61 patients without maintenance therapy were followed. Alternate day IFN was reasonably well tolerated by the majority of patients, but in 12% substantial non-haematological toxicity (including flu-like syndrome) occurred. One of 3 patients with pneumonitis died after having received 3.6 mg IFN. The median survival time from the date of randomisation was 8.9 months for the IFN arm and 9.9 months for the observation arm. rIFN-gamma at the dose and schedule used in this study failed to prolong response duration and survival in SCLC patients in complete or nearly-complete response. The toxicity seen with every other day doses of IFN was less than that reported with daily dosing. The hypothesis that this agent may increase the deleterious effects of radiation on normal lung tissue was supported by the development of pneumonitis in 3 cases of whom 1 had a fatal outcome. The results do not warrant further studies with rIFN-gamma on maintaining response in SCLC.

Randomised trial of two regimens of chemotherapy in operable osteosarcoma: a study of the European Osteosarcoma Intergroup

BACKGROUND

A previous trial by the European Osteosarcoma Intergroup (EOI) suggested that a short intensive chemotherapy regimen with doxorubicin and cisplatin might produce survival of operable, non-metastatic osteosarcoma similar to that obtained with complex and longer-duration drug regimens based on the widely used T10 multi-drug protocol. We undertook a randomised multicentre trial to compare these two approaches.

METHODS

407 patients with operable, non-metastatic osteosarcoma were randomly assigned the two-drug regimen (six cycles [18 weeks] of doxorubicin 25 mg/m2 on days 1-3 and cisplatin 100 mg/m2 on day 1) or a multi-drug regimen (preoperatively vincristine, high-dose methotrexate, and doxorubicin; postoperatively bleomycin, cyclophosphamide, dactinomycin, vincristine, methotrexate, doxorubicin, and cisplatin; this protocol took 44 weeks). Surgery was scheduled for week 9 for the two-drug group and week 7 for the multi-drug group. Analyses of survival and progression-free survival were by intention to treat.

FINDINGS

Of 407 randomised patients, 391 were eligible and have been followed up for at least 4 years (median 5-6 years). Toxic effects were qualitatively similar with the two regimens. However, 188 (94%) of 199 patients completed the six cycles of two-drug treatment, whereas only 97 (51%) of 192 completed 18 or more of the 20 cycles of the multi-drug regimen. The proportion showing a good histopathological response (> 90% tumour necrosis) to preoperative chemotherapy was about 29% with both regimens and was strongly predictive of survival. Overall survival was 65% at 3 years and 55% at 5 years in both groups (hazard ratio 0.94 [95% CI 0.69-1.27]). Progression-free survival at 5 years was 44% in both groups (hazard ratio 1.01 [0.77-1.33]).

INTERPRETATION

We found no difference in survival between the two-drug and multi-drug regimens in operable, non-metastatic osteosarcoma. The two-drug regimen is shorter in duration and better tolerated, and is therefore the preferred treatment. However, 5-year survival is still unsatisfactory and new approaches to treatment, such as dose intensification, are needed to improve results.

Randomized trial of alternating versus sequential radiotherapy/chemotherapy in limited-disease patients with small-cell lung cancer: a European Organization for Research and Treatment of Cancer Lung Cancer Cooperative Group Study

PURPOSE

To evaluate the effectiveness of alternating or sequential schedules of cyclophosphamide, doxorubicin, and etoposide (CDE) chemotherapy and irradiation in patients with previously untreated small-cell lung cancer (SCLC).

MATERIALS AND METHODS

A total of 335 eligible patients were randomized between five courses of CDE chemotherapy followed by thoracic irradiation 50 Gy in 20 daily fractions (S) and the same total dose of chemotherapy and irradiation split into four courses of five daily fractions delivered on days 14 to 21 of the second and subsequent chemotherapy courses (A). Patients had a median age of 61 years (range, 33 to 75); 224 (66%) were male; the Eastern Cooperative Oncology Group (ECOG) performance status (PS) was 0 or 1 in 311; and 254 had weight loss less than 10%.

RESULTS

The overall median survival duration was 15 months, with 62% (95% confidence interval [CI], 57% to 67%) 1-year, 25% (95% CI, 20% to 30%) 2-year, and 14% (95% CI, 10% to 18%) 3-year survival rates. There was no significant difference between the arms. The median survival time was 14 months in A and 15 months in S. One-year survival was 60% in A (95% CI, 53% to 67%) and 64% in S (95% CI, 57% to 71%); 2-year survival was 26% in A (95% CI, 19% to 33%) and 23% in S (95% CI, 16% to 30%); and 3-year survival was 12% in A (95% CI, 6% to 18%) and 15% in S (95% CI, 9% to 21%). World Health Organization (WHO) grade 3 and 4 neutropenia occurred in 90% of A and 77% of S patients (P < .001) and WHO grade 3 and 4 thrombocytopenia in 33% of A and 20% of S patients (P < .001). Rates of other acute and late toxicities were similar in both arms. Hematologic toxicity compromised treatment dose delivery; less than 50% of A patients received greater than 95% of prescribed chemotherapy and 77% their full radiation course, compared with 60% and 93% for arm S (P < .009). Local relapse was the site of first failure in 60% of all patients and 75% of these suffered an in-field relapse; no difference could be seen between the two arms.

CONCLUSION

This trial failed to confirm the superiority of an alternating schedule of delivery. For this combination of chemotherapy and irradiation, hematologic toxicity compromised treatment delivery and could have contributed to the overall result. The poor rates of local control are disappointing and require intensification of the radiation therapy strategy.

Gly-Gly-containing triplets of low stability adjacent to a type III collagen epitope

Collagens, in addition to their structural role in the extracellular matrix, possess a number of functional binding domains. In this study, the binding to collagen of a monoclonal antibody is used as a model to define the molecular features involved in triple-helix interactions with other proteins. Here we report the thermal stability of an overlapping set of triple-helical peptides that includes the epitope recognized by a monoclonal antibody to type III collagen. Although the sequences of these peptides are very closely related, by a translation of a single triplet along the collagen chain, substantial variations in the melting temperatures were observed. These variations in thermal stability could not be readily explained by differences in imino acid content, or in numbers of charged or hydrophobic residues. The results indicate that Gly-Gly-Y triplets, which are adjacent to the epitope, have a strong influence in reducing the thermal stability of triple-helical peptides. Further studies, which were carried out on a set of "host-guest" triple-helical peptides containing different Gly-Gly-Y guest triplets, confirm the destabilizing effect of such tripeptides. The presence of Gly-Gly-Y triplets may play an important role in specific functions of type III collagen by modulating the local triple-helical structure or dynamics.

Identification of the epitope for a monoclonal antibody that blocks platelet aggregation induced by type III collagen

A library of eight conformation-dependent monoclonal antibodies that react with distinct epitopes on native human type III collagen has been examined for the ability of these antibodies to inhibit platelet aggregation induced by this collagen. Six of these antibodies had no effects; one, 1E7-D7/Col3, delayed the onset and slowed the rate of platelet aggregation, while another, 2G8-B1/Col3, completely inhibited aggregation. In order to identify the epitope recognized by this inhibitory antibody, a series of peptides that could fold to form triple-helical fragments was examined. Each peptide included six Gly-Xaa-Yaa triplets from the human type III collagen sequence, where Xaa and Yaa represent the particular amino acids in the sequence, and a C-terminal (Gly-Pro-Hyp)4 sequence to enhance triple-helical stability. Using these peptides we have identified the epitope as a nine-amino-acid sequence, GLAGAOGLR (where O is the one-letter code for 4-hydroxyproline), starting at position 520 in the human type III collagen helical domain. This sequence is proximal to the site proposed for the interaction of type III collagen with alpha2beta1-integrin of platelets.

Phase II study on mitoxantrone in adenoid cystic carcinomas of the head and neck. EORTC Head and Neck Cancer Cooperative Group

BACKGROUND

Based on activity in a case report, mitoxantrone was studied in a phase II study in adenoid cystic carcinoma.

PATIENTS AND METHODS

Patients with symptomatic and/or rapidly progressive metastatic or recurrent adenoid cystic carcinoma were eligible for this study. They were treated with mitoxantrone given intravenously by bolus injection at a dose of 14 mg/m2, cycles repeated every 3 weeks.

RESULTS

Thirty-six chemotherapy-naive patients entered on trial, 4 were ineligible. A median of 6 cycles per patient were given. Leucocytopenia (in 97% of patients) was the most important side effect and tended to be cumulative. Other side effects were mainly mild to moderate and consisted of nausea (62%), vomiting (29%), alopecia (53%) and mucositis (41%). Four of 32 patients had a partial response (12%; 95% CI 4%-29%) lasting 3-13 months, 22 patients (69%) had a stable disease.

CONCLUSION

Mitoxantrone at this dose and schedule has modest activity in adenoid cystic carcinomas.

A host-guest set of triple-helical peptides: stability of Gly-X-Y triplets containing common nonpolar residues

Host-guest peptide sets have been useful in evaluating the propensity of different amino acids to adopt an alpha-helical or beta-sheet form, and this concept is applied here to the triple-helical conformation. A set of host-guest peptides of the form acetyl-(Gly-Pro-Hyp)3-Gly-X-Y-(Gly-Pro-Hyp)4-Gly-GlyCONH2 was designed to evaluate the contribution of an isolated Gly-X-Y triplet to triple-helix stability in a defined environment. Peptides were synthesized to include guest triplets with the X and Y positions occupied by the most common nonpolar residues found in collagen: Pro (X position) and Hyp (Y position); Ala; Leu, the most frequent hydrophobic residue; and Phe, the only commonly occurring aromatic residue. The guest triplets of the 12 peptides synthesized represent 35% of the sequence found in the alpha 1 chain of type I collagen. All peptides formed stable triple-helical structures, and the peptides showed a range of thermal stabilities (Tm = 21-44 degrees C), depending on the identity of the guest triplet. Thermodynamic calculations indicate these peptides have a range of free energy values (delta delta G = 9 kcal/mol) and suggest that favorable entropy is the dominant factor in increased stability. Replacement of Ala by Leu in the X position did not affect the thermal stability, while an Ala to Leu change in the Y position was destabilizing. These data provide experimental evidence that hydrophobic residues do not stabilize the triple helical conformation. Although Leu and Phe are found almost exclusively in the X position in collagens, peptides with Leu and Phe in the Y position formed stable triple-helices. This supports the hypothesis that the X positional preference of these residues relates to their increased potential for intermolecular hydrophobic interactions rather than their destabilization of the triple-helical molecule. These studies establish the utility of host-guest peptides in defining a scale of triple-helix propensities and in clarifying the interactions stabilizing the triple-helical conformation.

Standard versus alternating non-cross-resistant chemotherapy in extensive small cell lung cancer: an EORTC Phase III trial

Alternating chemotherapy for small cell lung cancer has been tested in several studies. Some have shown positive results that have not been confirmed in other studies. In all of the studies, however, the degree of non-cross-resistance in the regimens was questionable. The EORTC Lung Cancer Study Group developed two equipotent regimens: (i) standard (CDE)-cyclophosphamide, doxorubicin, etoposide; (ii) (VIMP)-vincristine, carboplatin, ifosfamide, mesna, both non-cross-resistance. These two combinations were alternated and compared with the standard chemotherapy regimen in a group of 143 patients with extensive small cell lung cancer. Median survival was 7.6 months in the standard arm and 8.7 in the alternating arm (P = 0.243). Median time to progression was 5.8 and 6.4 months, respectively (P = 0.166). Median response duration was 7.0 and 6.8 months (P = 0.221). The use of two alternating regimens with a proven degree of non-cross-resistance did not result in any improvement in survival in patients with extensive small cell lung cancer.

Larynx preservation in pyriform sinus cancer: preliminary results of a European Organization for Research and Treatment of Cancer phase III trial. EORTC Head and Neck Cancer Cooperative Group

BACKGROUND

As a general rule, surgery whenever possible, followed by irradiation is considered to be the standard treatment for cancer of the hypopharynx, thus sacrificing natural speech. In most patients, surgery includes removal of the larynx.

PURPOSE

A prospective, randomized phase III study was conducted by the European Organization for Research and Treatment of Cancer (EORTC) starting in 1990 to compare a larynx-preserving treatment (induction chemotherapy plus definitive, radiation therapy in patients who showed a complete response or surgery in those who did not respond) with conventional treatment (total laryngectomy with partial pharyngectomy, radical neck dissection, and postoperative irradiation) in previously untreated and operable patients with histologically proven squamous cell carcinomas of the pyriform sinus or aryepiglottic fold, but free of other cancers.

METHODS

Patients were randomly assigned to one of two treatment arms: 1) immediate surgery with postoperative radiotherapy (50-70 Gy) or 2) induction chemotherapy (cisplatin [100 mg/m2] given as a bolus intravenous injection on day 1, followed by infusion of fluorouracil [1000 mg/m2 per day] on days 1-5). An endoscopic evaluation was performed after each cycle of chemotherapy. After two cycles, only partial and complete responders received a third cycle. Patients with a complete response after two or three cycles of chemotherapy were treated thereafter by irradiation (70 Gy); nonresponding patients underwent conventional surgery with postoperative radiation (50-70 Gy). Salvage surgery was also performed when patients relapsed after chemotherapy and irradiation. The trial was designed to test the equivalence of the two treatment arms; i.e., the induction chemotherapy treatment would be judged equivalent to immediate surgery if the relative risk of death for induction chemotherapy compared with immediate surgery was significantly less than 1.43 using a one-sided hypothesis test at the .05 level of significance.

RESULTS

Two hundred two patients entered the trial and were randomly assigned; only 194 were eligible for treatment (94 in the immediate-surgery arm and 100 in the induction-chemotherapy arm). In the induction-chemotherapy arm, complete response was seen in 52 (54%) of 97 patients with local disease (primary tumor) and in 31 (51%) of 61 patients with regional disease (involvement of the neck). Treatment failures at local, regional, and second primary sites occurred at approximately the same frequencies in the immediate-surgery arm (12%, 19%, and 16%, respectively) and in the induction-chemotherapy arm (17%, 23%, and 13%, respectively). In contrast, there were fewer failures at distant sites in the induction-chemotherapy arm than in the immediate-surgery arm (25% versus 36%, respectively; P = .041). The median duration of survival was 25 months in the immediate-surgery arm and 44 months in the induction-chemotherapy arm and, since the observed hazard ratio was 0.86 (logrank test, P = .006), which was significantly less than 1.43, the two treatments were judged to be equivalent. The 3- and 5-year estimates of retaining a functional larynx in patients treated in the induction-chemotherapy arm were 42% (95% confidence interval = 31%-53%) and 35% (95% confidence interval = 22%-48%), respectively.

CONCLUSIONS AND IMPLICATIONS

Larynx preservation without jeopardizing survival appears feasible in patients with cancer of the hypopharynx. On the basis of these observations, the EORTC has now accepted the use of induction chemotherapy followed by radiation as the new standard treatment in its future phase III larynx preservation trials.

Dimerization of truncated melittin analogues results in cytolytic peptides

A synthetic peptide with the sequence of the first 20 residues of melittin and terminating with an additional cysteine amide was found to have cytolytic activity similar to that of melittin. It was apparent from MS data that the cysteine-terminating peptides had formed disulphide dimers. A peptide in which the thiol was blocked by iodoacetate showed no activity, whereas the same peptide blocked by acetamidomethyl showed activity marginally less haemolytic than that of melittin. Cytolytic activity of melittin analogues comprising the full 26 residues could be obtained with wide sequence permutations providing that a general amphipathic helical structure was preserved. In contrast, the activity of the dimers was dependent not only on retention of an amphipathic helix but also on certain individual residues and a free positive charge. A free N-terminus was essential for haemolytic activity. In addition, a lysine or arginine residue at position 7 and a proline at position 14 were found to be necessary for activity, although it was apparent that additional residues are important for retention of the full lytic potential.

Glycosylation of native MHC class Ia molecules is required for recognition by allogeneic cytotoxic T lymphocytes

The question whether or not target cell N-linked carbohydrate participates in cytotoxic T lymphocyte (CTL) mediated cytolysis has been in contention for well over a decade. Much of the evidence supporting a role for N-linked carbohydrate stems from the treatment of target cells with the glycosylation inhibitor tunicamycin (TM). In this report, we show that treatment of targets with TM, but not other inhibitors of complex carbohydrate formation (swainsonine, 1-deoxynojirimycin, and 1-deoxymannojirimycin), abrogates the lytic response. We conclude that N-linked complex carbohydrates are not absolutely required for the maturation or function of any target cell glycoconjugate directly involved in the lytic process. However, we show that TM treatment of target cells leads to the loss of an MHC class Ia epitope known to be required for T cell triggering. Further, we show that only target cells expressing class Ia molecules with functional glycosylation sequons are subject to the TM effect. From these results we conclude that while N-linked glycosylation of native MHC class Ia molecules is required for antigen presentation, the exact structural motif of the glycan is not important.

Peptide inhibitors of melittin action

The sequence of peptides necessary to inhibit melittin-induced lysis was studied using 13 peptide analogues of the inhibitor Ac-IVIFDC-NH2. Although this inhibitor is a disulfide-linked dimer, inhibition was equally effective if the thiol SH was blocked or replaced by methionine or lysine. The substitution of phenylalanine with other aromatic residues preserved activity, as did the replacement of aspartic acid by asparagine. The results suggest that the cytolytic activity of melittin can be inhibited by a short peptide of four hydrophobic residues followed by two other nonspecific residues. Fluorescence studies showed that the inhibitor caused a blue shift in the Trp emission spectrum. A spin label attached to the N-terminus of the inhibitor significantly quenched the fluorescence. These data confirmed the involvement of Trp 19 with the inhibitor, also predicted by molecular modeling of the probable binding site. Density gradient studies with large unilamellar vesicles indicated that the inhibitor prevented melittin from reacting with the lipid bilayer.

Cisplatin and etoposide combination chemotherapy for locally advanced or metastatic thymoma. A phase II study of the European Organization for Research and Treatment of Cancer Lung Cancer Cooperative Group

BACKGROUND

Thymomas are rare neoplasms of the mediastinum. The role of chemotherapy in advanced thymomas is not fully established.

PATIENTS AND METHODS

In the European Organization for Research and Treatment of Cancer (EORTC) Lung Cancer Cooperative Group, 16 patients with recurrent or metastatic malignant thymoma were entered over 6 years onto a study of combination chemotherapy that consisted of cisplatin 60 mg/m2 on day 1 and etoposide 120 mg/m2 on days 1, 2, and 3, every 3 weeks.

RESULTS

A median of six courses per patient was administered. Main side effects of treatment were leukopenia, nausea and vomiting, and alopecia. Five complete responses and four partial responses were obtained, with a median response duration of 3.4 years. The median progression-free survival and survival times were 2.2 years and 4.3 years, respectively, with a median follow-up duration of 7 years.

CONCLUSION

The combination of cisplatin and etoposide is highly effective and well tolerated in advanced thymoma. The investigation of this combination in a neoadjuvant setting in unresectable invasive thymoma is warranted.