A portable primary-standard level graphite calorimeter for absolute dosimetry in clinical pencil beam scanning proton beams

Objective. To report the use of a portable primary standard level graphite calorimeter for direct dose determination in clinical pencil beam scanning proton beams, which forms part of the recommendations of the proposed Institute of Physics and Engineering in Medicine (IPEM) Code of Practice (CoP) for proton therapy dosimetry.Approach. The primary standard proton calorimeter (PSPC) was developed at the National Physical Laboratory (NPL) and measurements were performed at four clinical proton therapy facilities that use pencil beam scanning for beam delivery. Correction factors for the presence of impurities and vacuum gaps were calculated and applied, as well as dose conversion factors to obtain dose to water. Measurements were performed in the middle of 10 × 10 × 10 cm3homogeneous dose volumes, centred at 10.0, 15.0 and 25.0 g·cm-2depth in water. The absorbed dose to water determined with the calorimeter was compared to the dose obtained using PTW Roos-type ionisation chambers calibrated in terms of absorbed dose to water in60Co applying the recommendations in the IAEA TRS-398 CoP.Main results.The relative dose difference between the two protocols varied between 0.4% and 2.1% depending on the facility. The reported overall uncertainty in the determination of absorbed dose to water using the calorimeter is 0.9% (k= 1), which corresponds to a significant reduction of uncertainty in comparison with the TRS-398 CoP (currently with an uncertainty equal or larger than 2.0% (k= 1) for proton beams).Significance. The establishment of a purpose-built primary standard and associated CoP will considerably reduce the uncertainty of the absorbed dose to water determination and ensure improved accuracy and consistency in the dose delivered to patients treated with proton therapy and bring proton reference dosimetry uncertainty in line with megavoltage photon radiotherapy.

Determination of beam quality correction factors for the Roos plane-parallel ionisation chamber exposed to very high energy electron (VHEE) beams using Geant4

Detailed characterisation of the Roos secondary standard plane-parallel ionisation chamber has been conducted in a novel 200 MeV Very High Energy Electron (VHEE) beam with reference to the standard 12 MeV electron calibration beam used in our experimental work. Stopping-power-ratios and perturbation factors have been determined for both beams and used to calculated the beam quality correction factor using the Geant4 general purpose MC code. These factors have been calculated for a variety of charged particle transport parameters available in Geant4 which were found to pass the Fano cavity test. Stopping-power-ratios for the 12 MeV electron calibration beam quality were found to agree within uncertainties to that quoted by current dosimetry protocols. Perturbation factors were found to vary by up-to 4% for the calibration beam depending on the parameter configuration, compared with only 0.8% for the VHEE beam. Beam quality correction factors were found to describe an approximately 10% lower dose than would be originally calculated if a beam quality correction were not accounted for. Moreover, results presented here largely resolve unphysical chamber measurements, such as collection efficiencies greater than 100%, and assist in the accurate determination of absorbed dose and ion recombination in secondary standard ionisation chambers.

Evaluation of the water-equivalence of plastic materials in low- and high-energy clinical proton beams

The aim of this work was to evaluate the water-equivalence of new trial plastics designed specifically for light-ion beam dosimetry as well as commercially available plastics in clinical proton beams. The water-equivalence of materials was tested by computing a plastic-to-water conversion factor, [Formula: see text]. Trial materials were characterized experimentally in 60 MeV and 226 MeV un-modulated proton beams and the results were compared with Monte Carlo simulations using the FLUKA code. For the high-energy beam, a comparison between the trial plastics and various commercial plastics was also performed using FLUKA and Geant4 Monte Carlo codes. Experimental information was obtained from laterally integrated depth-dose ionization chamber measurements in water, with and without plastic slabs with variable thicknesses in front of the water phantom. Fluence correction factors, [Formula: see text], between water and various materials were also derived using the Monte Carlo method. For the 60 MeV proton beam, [Formula: see text] and [Formula: see text] factors were within 1% from unity for all trial plastics. For the 226 MeV proton beam, experimental [Formula: see text] values deviated from unity by a maximum of about 1% for the three trial plastics and experimental results showed no advantage regarding which of the plastics was the most equivalent to water. Different magnitudes of corrections were found between Geant4 and FLUKA for the various materials due mainly to the use of different nonelastic nuclear data. Nevertheless, for the 226 MeV proton beam, [Formula: see text] correction factors were within 2% from unity for all the materials. Considering the results from the two Monte Carlo codes, PMMA and trial plastic #3 had the smallest [Formula: see text] values, where maximum deviations from unity were 1%, however, PMMA range differed by 16% from that of water. Overall, [Formula: see text] factors were deviating more from unity than [Formula: see text] factors and could amount to a few percent for some materials.

Reference dosimetry for light-ion beams based on graphite calorimetry

Developments in hadron therapy require efforts to improve the accuracy of the dose delivered to a target volume. Here, the determination of the absorbed dose under reference conditions was analysed. Based on the International Atomic Energy Agency TRS-398 code of practice, for hadron beams, the combined standard uncertainty on absorbed dose to water under reference conditions, derived from ionisation chambers, is too large. This uncertainty is dominated by the beam quality correction factors, [Formula: see text], mainly due to the mean energy to produce one ion pair in air, wair. A method to reduce this uncertainty is to carry out primary dosimetry, using calorimetry. A [Formula: see text]-value can be derived from a direct comparison between calorimetry and ionometry. Here, this comparison is performed using a graphite calorimeter in an 80-MeV A(-1) carbon ion beam. Assuming recommended TRS-398 values of water-to-graphite stopping power ratio and the perturbation factor for an ionisation chamber, preliminary results indicate a wair-value of 35.5 ± 0.9 J C(-1).

Abstract P5-17-05: Sorafenib plus Ixabepilone as First-Line Treatment for Patients with HER2-Negative Metastatic Breast Cancer: Preliminary Results of the Phase II Trial of the Sarah Cannon Research Institute

Background: Sorafenib (S) is an oral multi-kinase inhibitor with effects on tumor proliferation and angiogenesis, targeting VEGFR1 and VEGFR2. It has modest activity as a single agent in breast cancer. In combination with capecitabine, S demonstrated a significant improvement of 2.3 months in progression free survival (PFS) in patients (pts) with metastatic breast cancer (MBC) and added benefit when combined with paclitaxel. Ixabepilone (Ixa) is a semi-synthetic analog of epothilone B with excellent single agent activity in MBC. The phase I portion of this trial identified the MTD of the Ixa and S combination. We now report the initial results of the phase II trial with this novel combination.

Methods: Eligibility criteria included: HER2-negative MBC previously untreated with chemotherapy; measurable disease; ECOG PS 0–2; normal LVEF; and adequate bone marrow and organ function. Prior hormonal therapy for MBC was permitted. Pts received Ixa 32mg/m2 IV on day 1 of each 21-day cycle and S 400mg PO BID. Following a minimum of 4 cycles of the combination, responding pts could discontinue Ixa and remain on study treatment with S monotherapy. Granulocyte-stimulating growth factors were permitted after cycle one. Tumor assessments were performed every 9 weeks. Pts continued study treatment until disease progression or unacceptable toxicity. The primary endpoint of this trial was PFS; the addition of S to Ixa was hypothesized to improve PFS from 4.2 month to 6.2 months in this patient population. The total enrollment goal is 85 pts, and the trial is currently open to accrual.

Results: Between 5/2010 and 4/2012, 76 pts have been enrolled, and 57 pts (56 females, 1 male) are included in this analysis. Baseline characteristics included: median age 58; 61% were ER and/or PR positive; 39% were triple-negative; 39% received neoadjuvant therapy. Anthracycline exposure was noted in 34 pts and prior taxane exposure in 39 pts. 29 pts received prior hormonal therapy, 7 of these for MBC. Sites of metastatic disease included lymph nodes 42%, lung 35%, liver 30%, bone 30%, and 23% other. 19 pts (33%) had 3 or more sites of metastatic disease. Median treatment duration was 3 cycles (9 weeks), range 1–11+ cycles with 9 pts discontinuing Ixa after a median of 6 cycles and continuing on S monotherapy. 12 pts (21%) had objective responses (1 CR, 11 PR); 3 of the 22 (14%) triple-negative patients had responses (1 CR, 2 PR). An additional 24 patients (42%) had stable disease at first reevaluation. Neutropenia was the most common grade 3/4 toxicity (26%) with growth factor use reported in 35%. Grade 3/4 non-hematologic toxicity occurring in > 5% of patients consisted of: rash (12%), fatigue (11%), hypersensitivity reaction (7%, Ixa= 3 pts and S= 1 pt), and neuropathy (7%). Discontinuation due to adverse events occurred in 11%.

Conclusion: The combination of Ixa and full dose S was well tolerated with no new observed toxicities. Adverse events were manageable and consisted primarily of G3/4 neutropenia and rash. Study is ongoing and updated results will be presented.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-17-05.

Efficacy results from a multicenter phase II noncomparative two-arm pilot trial of bevacizumab with anastrozole or fulvestrant as first-line endocrine therapy for metastatic breast cancer

1091

Background: Estrogen modulates angiogenesis via effects on endothelial cells with subsequent induction of vascular endothelial growth factor (VEGF). VEGF promotes tumor growth and is associated with poor response to antiestrogen therapy. This trial was designed to evaluate the progression-free survival (PFS) of bevacizumab (B) in combination with anastrozole (A) or fulvestrant (F) as first-line endocrine therapy (ET) in metastatic breast cancer (MBC). Methods: Eligibility criteria: no prior hormonal or chemotherapy for MBC, measurable or evaluable disease, normal LVEF, post-menopausal. Treatment: Arm A: anastrozole 1 mg po QD in pts who were a) ET naïve, b) ≥ 12 months from adjuvant ET, and c) intolerant of or progressed on prior tamoxifen. Arm B: fulvestrant 500 mg D1 and 250 mg D15 IM loading dose followed by 250 mg q28 days in pts who were a) < 12 months from adjuvant aromatase inhibitors (AIs), b) intolerant of or progressed on AIs, and c) MD's discretion. Bevacizumab 10 mg/kg IV D1 q2 weeks was given in both arms. Trastuzumab permitted in HER-2+ pts only. Response assessments were q8 weeks; pts were treated until disease progression or toxicity. Results: 79 pts were enrolled fromNovember 2006 to November 2008. 42 pts are evaluable for response and toxicity, Arm A - 25 pts and Arm B - 17 pts. Median age was 64, ECOG PS 0 - 55%, 1- 43 %, adjuvant chemo 27%, adjuvant hormonal -38%, hormone receptor status: ER+/PR+ 80%, ER+/PR- 14%, ER-/PR+ 2 %. HER-2+ 5 pts, 31% had ≥ 2 metastatic disease sites predominately lung and bone only disease - 40%. Median # cycles - 4. 24% achieved a partial response and 57% stable disease; 7 pts progressed. G3 hypertension (12%) was the most common toxicity. Median PFS for Arm A was 16.3 months and has not yet been reached for Arm B. Conclusions: Bevacizumab in combination with anastrozole or fulvestrant is feasible and well tolerated with no unanticipated toxicities. The addition of bevacizumab resulted in prolongation of the median PFS to16.3 months with anastrozole as compared to the 7–9 month historical control PFS reported for first-line AI monotherapy in MBC. Further evaluation of bevacizumab endocrine combinations is warranted.

[Table: see text]

Combined modality therapy with radiation therapy (RT), chemotherapy, bevacizumab, and erlotinib in the treatment of patients (pts) with locally advanced squamous carcinoma of the head and neck

6012

Background: Concurrent chemotherapy/RT is the standard of treatment for locally advanced head and neck cancer. Agents targeting EGFR and the angiogenesis pathway have also demonstrated activity. In this phase II trial, we added bevacizumab and erlotinib to an active combined modality regimen in the first-line treatment of pts with locally advanced head and neck cancer. Methods: Eligible pts had previously untreated squamous carcinoma of any head and neck site, with T3/T4 primary lesions and/or N1-N3 nodal involvement. Additional eligibility: ECOG PS 0 or 1; adequate organ function; indwelling central venous catheter; standard bevacizumab exclusions. All pts received induction therapy with 2 courses of paclitaxel (200mg/m2), carboplatin (AUC 6.0), 5-FU (200mg/m2 per day, 24 hour CI days 1–21), and bevacizumab (15 mg/kg); cycles were repeated at 21-day intervals. Pts then received concurrent RT (68.4 Gy, 1.8 Gy/day), paclitaxel (50 mg/m2 weekly x 6), bevacizumab (15 mg/kg weeks 1 and 4), and erlotinib (150 mg daily x 7 weeks). PFS was the primary endpoint. Results: Between December 2006 and July 2008, 60 pts were enrolled; the first 48 pts are included in this preliminary report. The median age was 56 years; T3/T4 = 9/8; N1/N2/N3 = 13/27/4. 45 pts (94%) completed the 6-week induction therapy, and 41 pts (85%) completed all therapy. After induction therapy, 56% of pts had objective response; 77% had objective response after completion of therapy. After a median follow-up of 16 months, the 18-month progression-free and overall survivals are 85% and 87%, respectively. Grade 3/4 toxicity during induction therapy included neutropenia (46%), neutropenic fever (6%), mucositis (14%), diarrhea (14%), and hand/foot syndrome (11%). Severe local toxicity (mucositis/esophagitis) occurred in 31 patients (76%) during combined modality therapy (56% grade 3/20% grade 4). Conclusions: The addition of bevacizumab and erlotinib to concurrent chemotherapy/RT was feasible, with no unexpected toxicity. After short followup, the regimen appears highly active. Updated results will be presented.

[Table: see text]

Randomized phase III comparison of paclitaxel/carboplatin/etoposide versus gemcitabine/irinotecan, both followed by gefitinib, in patients (pts) with carcinoma of unknown primary site (CUP)

4631

Background: Empiric chemotherapy for pts with CUP has resulted in modest survival improvements. Several regimens have been active in phase II trials, but no randomized comparison of newer regimens have been completed. In this multicenter randomized phase III trial, we compared the efficacy and toxicity of 2 active regimens. Methods: Previously untreated pts with CUP (adenocarcinoma, poorly differentiated adenocarcinoma, poorly differentiated carcinoma, poorly differentiated squamous carcinoma) were eligible. Pts with specific treatable syndromes were excluded. Additional eligibility: ECOG PS 0–2; controlled brain metastases; adequate organ function. Pts were randomized (1:1) to paclitaxel 200mg/m2 day 1/carboplatin AUC 6.0 day 1/etoposide 50mg/100mg alternating po days 1–10 (PCE) or gemcitabine 1000mg IV days 1, 8/irinotecan 100mg/m2 IV days 1, 8 (GI). Both regimens were repeated at 21-day intervals for 4–6 courses. Responding/stable pts then received gefitinib 250mg po qd until tumor progression. The primary endpoint was the 2-year survival rate. Initially, a total of 320 pts were planned, to allow detection of a 50% improvement in 2-year survival (from 20% to 30%). However, due to slow accrual, enrollment was stopped after 198 pts were randomized. Results: Between September 2003 and July 2008, 198 pts were randomized (PCE, 93 patients; GI 105 patients). Pt characteristics were similar in both groups. Median progression-free survival for PCE versus GI was 3.2 months versus 5.3 months, p=0.19. Median overall survivals were 7.4 months (PCE) versus 8.6 months (GI), p=0.34; 2-year survivals were 16% (PCE) and 19% (GI). Response rates were similar (PCE 19%, GI 20%). GI was less toxic, with lower rates of grade 3/4 neutropenia (11% vs. 35%; p< 0.01), febrile neutropenia (0% vs. 9%; p<0.01), thrombocytopenia (3% vs. 8%; p=.05), anemia (3% vs. 9%; p=0.05), and RBC transfusions (10% vs. 24%; p<0.01). Conclusions: The PCE and GI regimens had comparable efficacy in the treatment of CUP, while the GI regimen was better tolerated. The 2-year survival was similar (16%, 19%). Better treatments are needed for pts with CUP.

[Table: see text]

Phase II trial of satraplatin and paclitaxel in the first-line treatment of advanced non-small cell lung cancer

18073

Background: Satraplatin (S) is a novel oral platinum analogue that has shown promising activity in a number of solid tumor settings. Our center previously conducted a phase I trial combining S and paclitaxel (P) in patients (pts) with refractory malignancies, establishing safety for this combination. This single center community-based trial was designed to examine the role of S/P in pts with newly diagnosed advanced non-small cell lung cancer (NSCLC). Methods: The primary endpoint is the objective response rate (ORR). Eligibility criteria: newly diagnosed and unresectable stage IIIB/IV NSCLC, measurable disease, ECOG PS 0–2, and informed consent. Treatment: S 80 mg/m2 PO days 1–5 and P 200mg/m2 IV day 1, every 28 days for a maximum of 6 cycles. Pts were restaged every 8 weeks. Results: 28 pts were enrolled from 2/06 to 12/06 (trial ongoing, n = 40 planned). Data are available on 24 pts for analysis. Baseline characteristics: median age 67 years; male/female, 58%/42%; and ECOG PS 0/1/2, 25%/63%/12%; adenocarcinoma/squamous/large cell/unspecified, 33%/42%/1%/24%. The ORR was 17% (95% CI 5%-37%). 10 pts (42%) had stable disease (SD) and 5 pts (21%) had progressive disease. The disease control rate (ORR + SD) was 59%. 5 pts were not evaluable due to: death (3 pts - 1 possibly due to treatment- related sepsis), and physician/pt preference (1 pt each). With a median follow-up of 8.3 months, the median time to progression is 4 months. Grade (G) 3/4 non-hematologic toxicity occurring in = 5%: infection (29%), nausea, vomiting (17% each), anorexia, hyperglycemia (13% each), and fatigue (8%). G3/4 hematologic toxicity: leukopenia (21%), neutropenia (41%), and thrombocytopenia (29%). Conclusions: In this preliminary analysis, S/P appears to have comparable activity to other platinum-based regimens. In an effort to reduce myelosuppression this trial has been amended to a S dose of 70 mg/m2. Additional accrual and follow-up are needed to better assess the safety and efficacy of this combination regimen.

No significant financial relationships to disclose.

Atypical cutaneous leishmaniasis in two patients receiving low-dose methotrexate

Cutaneous leishmaniasis is a protozoan disease that has high morbidity. There have been increasing reports of leishmaniasis in patients with an underlying immunosuppressed state. We present two cases of cutaneous leishmaniasis caused by Old World species in patients on methotrexate therapy. We postulate that the T-cell-mediated response to leishmaniasis infection could be modulated by methotrexate and may render an immunosuppressed individual more susceptible to developing clinical disease.

Phase II trial of gemcitabine and carboplatin, plus trastuzumab in HER2+ patients as first line therapy in metastatic breast cancer

10590

Background: Gemcitabine (G) and carboplatin (C) demonstrate significant preclinical synergy together as well as in combination with trastuzumab (H) in metastatic breast cancer (MBC) pts. This multicenter phase II trial evaluates the efficacy and safety of G + C with trastuzumab in HER2 + pts as 1st line therapy in MBC. Methods: Eligibility requirements: females > 18 with no prior regimens for MBC, ECOG 0–2, RECIST bidimensional disease, and adequate organ function. FISH HER2 + pts received H with GC. Treatment: G 1,000 mg/m2 D1& 8 with C AUC 5 D1 in the first 20 pts. Following a toxicity assessment revealing significant myelosuppression, C was administered in subsequent pts at AUC 4. 14 HER2+ pts received H 8 mg/kg loading dose followed by 6 mg/kg q21 days. Pts were evaluated for response after 9 weeks; treatment continued until progression or toxicity except in HER2+ pts who received up to 6 cycles GCH followed by single agent H. Results: Between 11/03 & 11/05, 45 pts have been treated: median age 55 for GC, 65 for GCH, ECOG 0/1 22/23. 19 pts were chemonaive. 26 pts received prior adjuvant chemotherapy: 20 pts adjuvant anthracyclines (A) & taxanes (T), 3 only prior A and 3 prior T. 73% had 2 or more metastatic sites of disease. 31 pts received GC & 14 pts received GCH. 18 of 41 evaluable pts (44%) had objective responses (PR 16, CR 2) with 17 pts (42%) exhibiting SD & 6 pts PD (15%). 91% of AT pretreated pts demonstrated SD or better. 9 remain on study. 6 went off study due to heme related toxicities and 9 due to MD discretion [4 max benefit, 3 XRT]. Median # of cycles was 5. Combined G3/4 hematologic toxicity was notable for 66% neutropenia (only 1 FN), 55% thrombocytopenia, and 32% anemia, predominately occurring at the carboplatin AUC 5 dose level. Transfusions of PRBCs and plts were administered in 14 and 8 pts respectively. Nonhematologic toxicity was minimal and remarkable for G3/4 fatigue in 20%. Conclusions: In FISH HER2+ pts, the addition of trastuzumab to GC yielded a 50% RR, with no evident cardiotoxicity. The combination of gemcitabine with carboplatin AUC 4 is active, albeit with moderate hematologic toxicity, warranting further exploration of alternate GC ± H schedules in breast cancer.

[Table: see text]

Perturbation correction factors for the NACP-02 plane-parallel ionization chamber in water in high-energy electron beams

Recent dosimetry protocols for clinical high-energy electron beams recommend measurements of absorbed dose-to-water with a plane-parallel or cylindrical ionization chamber. For well-guarded plane-parallel ionization chambers, the ionization chamber perturbation factor in water, p(Q), has a recommended value of unity in all protocols. This assumption was investigated in detail in this study for one of the recommended ionization chambers in the protocols: the Scanditronix NACP-02 plane-parallel ionization chamber. Monte Carlo (MC) simulations of the NACP-02 ionization chamber with the EGSnrc code were validated against backscatter experiments. MC simulations were then used to calculate p(wall), p(cav) and p(Q) perturbation factors and water-to-air Spencer-Attix stopping powers in 4-19 MeV electron beams of a calibration laboratory (NPL), and in 6-22 MeV clinical electron beams from a Varian CL2300 accelerator. Differences between calculated and the currently recommended (Burns et al 1996 Med. Phys. 23 383-8) stopping powers, water-to-air, were found to be limited to 0.9% at depths between the reference depth z(ref) and the depth where the dose has decreased to 50% of the maximum dose, R50. p(wall) was found to exceed unity by 2.3% in the 4 MeV NPL calibration beam at z(ref). For higher energy electron beams p(wall) decreased to a value of about 1%. Combined with a p(cav) about 1% below unity for all energies at z(ref), this was found to cause p(Q) to exceed unity significantly for all energies. In clinical electron beams all three perturbation factors were found to increase with depth. Our findings indicate that the perturbation factors have to be taken into account in calibration procedures and for clinical depth dose measurements with the NACP-02 ionization chamber.

Drug-induced urticaria. Recognition and treatment

Urticaria is the second most common cutaneous manifestation of drug allergy. Drug-induced urticaria is seen in 0.16% of medical inpatients and accounts for 9% of chronic urticaria or angioedema seen in dermatology outpatient departments. Occurring within 24 hours of drug ingestion, it is most commonly caused by penicillins, sulfonamides and nonsteroidal anti-inflammatory drugs. Drug-induced urticaria is seen in association with anaphylaxis, angioedema, and serum sickness. Diagnosis requires a detailed history, knowledge of the most likely agents sometimes supplemented with in vitro and skin testing. For mild reactions, avoidance of the causative drug and treatment with antihistamines will suffice. For anaphylactic shock, treatment with epinephrine (adrenaline), corticosteroids and antihistamines is required. Patients should be educated to inform medical staff about previous drug reactions, and to avoid these and cross-reacting drugs if possible. Medical staff need to routinely enquire about allergy and avoid unnecessary prescriptions.

Moderate alcohol consumption does not augment bone density in ovariectomized rats

Moderate levels of alcohol consumption have been reported to have a beneficial effect on bone mineral density in postmenopausal women. The objective of this study was to examine the effect of a moderate level of alcohol consumption on bone density in a rigorously controlled animal model of osteoporosis. Ovariectomized and nonovariectomized rats were placed on standard lab pellets with free access to deionized water ad libitum. Alcohol-treated animals were given 0.38 g/kg of alcohol daily by intubation in the mid-afternoon and free access to standard lab pellets for 6 weeks. The amount of the alcohol solution was calculated daily to give the human equivalent of 2 glasses of wine/day. Pair-fed control animals were given, on the following day, an equal volume of the diet consumed by individual ethanol-fed rats. They received daily intubation solutions, with the ethanol replaced by isocaloric and isovolumetric amounts of maltose-dextrin. Chow-fed control animals received no intubations and were given access to standard lab pellets ad libitum. Ovariectomized animals had increased weight and decreased femur density and bone volume per total volume. They also had decreased total trabecular area, trabecular area, and number, as well as increased trabecular separation. Significant differences were found between the ovariectomized and nonovariectomized animals in the parameters under discussion, but there were no differences between diet groups. No beneficial effects were found after daily alcohol treatments.

The haemoglobin-like protein (HMP) of Escherichia coli has ferrisiderophore reductase activity and its C-terminal domain shares homology with ferredoxin NADP+ reductases

Three soluble ferrisiderophore reductases (FsrA, FsrB and FsrC) were detected in Escherichia coli. FsrB was purified and identified as the haemoglobin-like protein (HMP) by size and N-terminal sequence analyses. HMP was previously isolated as a dihydropteridine reductase and is now shown to have ferrisiderophore reductase activity. Database searches revealed that the C-terminal region of HMP (FsrB) is homologous to members of a family of flavoprotein oxidoreductases which includes ferredoxin NADP+ reductase (FNR). The combination of FNR-like and haemoglobin-like regions in HMP (FsrB) represents a novel pairing of functionally and structurally distinct domains. Structure-function properties of other FNR-like proteins, including LuxG and VanB, are also discussed.