Abiotic factors influencing soil microbial activity in the northern Antarctic Peninsula region

Microorganisms play a key role in the carbon (C) cycle through soil organic matter (SOM). The rate of SOM mineralization, the influence of abiotic factors on this rate and the potential behaviour of SOM are of particular interest in the northern Antarctic Peninsula and offshore islands. This is one of the most rapidly warming regions on Earth with numerous ice-free areas, some with abundant wildlife and with the greatest known soil organic carbon (SOC) storage in Antarctica. The latter implies extended Antarctic summer conditions promote increased terrestrial plant growth and soil microbial activity (SMA). SMA, determined by respirometry, is a measure of ecosystem function, and depends on microclimatic conditions and soil environmental properties. SMA and the effect of abiotic variables have been analysed in locations with different soil types, on Cierva Point (Antarctic Peninsula), Deception Island and Fildes Peninsula (King George Island). Soil microbial biomass carbon (SMBC) ranged from 5.66 to 196.6 mg SMBC kg^-1and basal respiration (BR) from 2.86 to 160.67 mg CO₂ kg^-1 d^-1. SMBC and BR values were higher in Cierva Point, followed by Fildes Peninsula and Deception Island, showing the same trend of SOM abundance_. Except for Cierva Point, low nitrogen, phosphorus and C concentrations were observed. SMBC/total organic carbon (TOC) levels indicated that SOC was recalcitrant and SOM content was closely related to the extent of vegetation cover observed in situ. High metabolic quotient values obtained at Cierva Point and Deception Island (median values 7.27 and 6.53 mg C-CO₂ g SMBC^-1 h^-1) and low SMBC/TOC in Cierva Point suggest a poor efficiency of the microbial populations in the consumption of the SOC. High SMBC/TOC values obtained in Deception Island indicates that SMBC may influence SOM stabilization. Mineralization rates were very low (negligible values to 1.44%) and sites with the lowest values had the highest SOM.

Phase Ib study of eribulin (ERB) and cyclophosphamide (CTX) in metastatic breast cancer (MBC)

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Background: ERB is a non-taxane microtubule inhibitor approved for the treatment (Tx) of taxane (TAX) and anthracycline-treated MBC based on improved OS compared to treatment of physician choice. In the adjuvant setting, docetaxel/CTX (TC) was superior to doxorubicin/CTX for DFS and OS. ERB is active in TAX-resistant disease with a low rate of peripheral neuropathy (PN); its primary dose-limiting toxicity (DLT) is bone marrow suppression. We hypothesized that the combination of ERB and CTX would be well tolerated and active in patients with TAX-resistant disease, with potential applicability to the adjuvant setting. Methods: We designed a 3+3 phase Ib study of ERB, administered in 2 escalating doses on day 1 and 8, with CTX 600 mg/m2day 1 every 21 days. Eligibility included PN ≤ grade 1. Correlative studies to identify predictors of response and toxicity included whole blood for SNPs, GWAS, circulating tumor cells (CTC), and archived tumor RNA/protein expression analysis. Toxicity assessment included QoL and evaluation of PN. Results: 6 patients (pts) with MBC, median age 50 (47-63), were enrolled. All pts had prior TAX exposure and 4 pts had baseline grade 1 PN. Tumor characteristics included hormone receptor + (5 pts), HER2+ (2 pts), and triple-negative (1 pt). Median number of prior Tx for MBC was 5 (1-8). No DLTs were observed; the RP2D is eribulin 1.4 mg/m2 on D1 and D8 with CTX D1 600mg/m2. Neutropenia was the only G3/G4 non-DLT observed at this dose, requiring GCSF support in cycle 1 in 2 of 3 pts. All grade toxicities included neutropenia (50%), thrombocytopenia, fatigue, nausea, PN, rash, mucositis, alopecia (33% each), and elevated liver enzymes (17%). Pts received a median of 5.5 cycles (range 3-13), with 3 pts still on Tx. Responses included 2PRs (33%) and 4 SD (67%). 2 pts stopped study Tx for QoL and continued ERB alone. Only 2 pts met threshold of >5CTC/7.5ml at baseline; these had a mean decrease of 90.5% at the start of cycle 2. Conclusions: ERB and CTX is a well-tolerated regimen with promising activity in MBC, with the primary toxicity being neutropenia requiring growth factor support. A phase II study in MBC is underway. Additional correlative studies are ongoing, including molecular analyses of CTC. Clinical trial information: NCT01554371.

Phase Ib study of eribulin (ERB) and cyclophosphamide (CTX) in metastatic breast cancer (MBC)

1095

Background: ERB is a non-taxane microtubule inhibitor approved for the treatment (Tx) of taxane (TAX) and anthracycline-treated MBC based on improved OS compared to treatment of physician choice. In the adjuvant setting, docetaxel/CTX (TC) was superior to doxorubicin/CTX for DFS and OS. ERB is active in TAX-resistant disease with a low rate of peripheral neuropathy (PN); its primary dose-limiting toxicity (DLT) is bone marrow suppression. We hypothesized that the combination of ERB and CTX would be well tolerated and active in patients with TAX-resistant disease, with potential applicability to the adjuvant setting. Methods: We designed a 3+3 phase Ib study of ERB, administered in 2 escalating doses on day 1 and 8, with CTX 600 mg/m2day 1 every 21 days. Eligibility included PN ≤ grade 1. Correlative studies to identify predictors of response and toxicity included whole blood for SNPs, GWAS, circulating tumor cells (CTC), and archived tumor RNA/protein expression analysis. Toxicity assessment included QoL and evaluation of PN. Results: 6 patients (pts) with MBC, median age 50 (47-63), were enrolled. All pts had prior TAX exposure and 4 pts had baseline grade 1 PN. Tumor characteristics included hormone receptor + (5 pts), HER2+ (2 pts), and triple-negative (1 pt). Median number of prior Tx for MBC was 5 (1-8). No DLTs were observed; the RP2D is eribulin 1.4 mg/m2 on D1 and D8 with CTX D1 600mg/m2. Neutropenia was the only G3/G4 non-DLT observed at this dose, requiring GCSF support in cycle1 in 2 of 3 pts. All grade toxicities included neutropenia (50%), thrombocytopenia, fatigue, nausea, PN, rash, mucositis, alopecia (33% each), and elevated liver enzymes (17%). Pts received a median of 5.5 cycles (range 3-13), with 3 pts still on Tx. Responses included 2PRs (33%) and 4 SD (67%). 2 pts stopped study Tx for QoL and continued ERB alone. Only 2 pts met threshold of >5CTC/7.5ml at baseline; these had a mean decrease of 90.5% at the start of cycle 2. Conclusions: ERB and CTX is a well-tolerated regimen with promising activity in MBC, with the primary toxicity being neutropenia requiring growth factor support. A phase II study in MBC is underway. Additional correlative studies are ongoing including molecular analyses of CTC. Clinical trial information: NCT01554371.

Chemotherapy versus best supportive care for extensive small cell lung cancer

BACKGROUND

Combination chemotherapy has been the mainstay of treatment for extensive stage small cell lung cancer (SCLC) over the last 25 years even though it only gives a short prolongation in median survival time. The main goal for these patients, if their survival prognosis is limited, should be adequate palliation with the aim of improving their quality of life.

OBJECTIVES

To evaluate the effectiveness of chemotherapy in extensive SCLC compared with best supportive care (BSC) or placebo treatment.

SEARCH STRATEGY

Medline (1966-Jan 2003), Embase (1974-Jan 2003), Cancerlit (1993-Jan 2003) and the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 4, 2002) were searched. In addition experts in the field were contacted to identify further studies not found by electronic searches.

SELECTION CRITERIA

Randomised controlled trials in which any chemotherapy treatment was compared with a placebo group or best supportive care in patients with extensive stage SCLC.

DATA COLLECTION AND ANALYSIS

Data extraction and quality assessment were undertaken independently by two reviewers and disagreements were resolved by a third author. Additional information on the included studies was obtained from the author of the original studies.

MAIN RESULTS

Only two studies (the first published in 1977 and the second in 1982) met the inclusion criteria of the review. A total of 65 patients with extensive disease (33 in the first study and 32 in the second) were randomised to received either placebo treatment or ifosfamide. In the second study a third arm of comparison included ifosfamide plus CCNU. Ifosfamide gave an extra 78.5 days survival (mean survival time) compared with the placebo group. Partial tumour response was greater with the active treatment. Toxicity was only seen in the chemotherapy group. Pooled analysis was not possible because only mean survival time was reported in both studies for patients with extensive disease.

REVIEWER'S CONCLUSIONS

Chemotherapeutic treatment prolongs survival in comparison with placebo in patients with advanced SCLC. Nevertheless the impact of chemotherapy on quality of life and in patients with poor prognosis is unknown. Well-designed, controlled trials are needed to further evaluate the risks and benefits of different chemotherapeutic schedules in patients with advanced small cell lung cancer.

Uranium isotopic distribution in the mineral phases of granitic fracture fillings by a sequential extraction procedure

In order to study the recent rock-water interaction processes in the E1 Berrocal site, a sequential leaching method has been applied to granitic fracture fillings to obtain the U isotopic distribution in the mineral phases of these samples. Based on the mineralogical composition of these materials, six dissolution steps have been chosen to extract U as exchangeable cation, from carbonates, amorphous Fe-oxyhydroxides, labile resistates and highly insoluble resistates. In this way, the processes involved in the rock-water interaction phenomena, mainly dissolution, precipitation, coprecipitation and adsorption can be distinguished and even approximately dated.

[Multiple hydatid embolism: acute ischemia of the right lower limb. Apropos of a case]

This case report presents a cardiac hydatidosis with multiple embolisms on several vascular territories, such as right popliteal artery, which was treated by embolectomy. Convenience of surgical approach, followed by medical treatment, in order to avoid a new recurrence, and periodical controls every 3-6 months (at least) during several years after disease, was evaluated.