The importance of Antarctic krill in biogeochemical cycles

Antarctic krill (Euphausia superba) are swarming, oceanic crustaceans, up to two inches long, and best known as prey for whales and penguins - but they have another important role. With their large size, high biomass and daily vertical migrations they transport and transform essential nutrients, stimulate primary productivity and influence the carbon sink. Antarctic krill are also fished by the Southern Ocean's largest fishery. Yet how krill fishing impacts nutrient fertilisation and the carbon sink in the Southern Ocean is poorly understood. Our synthesis shows fishery management should consider the influential biogeochemical role of both adult and larval Antarctic krill.

Pregnancy limits lung function during exercise and depresses metabolic rate in the skink Tiliqua nigrolutea

High gestational loads have been associated with a range of ecological costs, such as decreased locomotor ability; however, the physiological mechanisms that underpin these changes are poorly understood. In this study, breathing patterns, metabolic rates, lung volume and lung diffusing capacity were measured at rest and during exercise in the pregnant skink Tiliqua nigrolutea. Breathing patterns were largely unaffected by gestation; however, decreases in metabolic rate (rate of oxygen consumption) in the late stages of pregnancy induced a relative hyperventilation. The reductions in metabolic rate during late pregnancy prevent the calculation of the maintenance cost of pregnancy based on post-partum and neonatal metabolic rates. Despite the high relative litter mass of 38.9±5.3%, lung diffusing capacity was maintained during all stages of pregnancy, suggesting that alterations in diffusion at the alveolar capillary membrane were not responsible for the relative hyperventilation. Lung volume was increased during pregnancy compared with non-pregnant females, but lung volume was significantly lower during pregnancy compared with post-partum lung volume. Pregnant females were unable to produce the same metabolic and ventilatory changes induced by exercise in non-pregnant females. This lack of ability to respond to increased respiratory drive during exercise may underpin the locomotor impairment measured during gestation in previous studies.

Echidna venom gland transcriptome provides insights into the evolution of monotreme venom

Monotremes (echidna and platypus) are egg-laying mammals. One of their most unique characteristic is that males have venom/crural glands that are seasonally active. Male platypuses produce venom during the breeding season, delivered via spurs, to aid in competition against other males. Echidnas are not able to erect their spurs, but a milky secretion is produced by the gland during the breeding season. The function and molecular composition of echidna venom is as yet unknown. Hence, we compared the deeply sequenced transcriptome of an in-season echidna crural gland to that of a platypus and searched for putative venom genes to provide clues into the function of echidna venom and the evolutionary history of monotreme venom. We found that the echidna venom gland transcriptome was markedly different from the platypus with no correlation between the top 50 most highly expressed genes. Four peptides found in the venom of the platypus were detected in the echidna transcriptome. However, these genes were not highly expressed in echidna, suggesting that they are the remnants of the evolutionary history of the ancestral venom gland. Gene ontology terms associated with the top 100 most highly expressed genes in echidna, showed functional terms associated with steroidal and fatty acid production, suggesting that echidna “venom” may play a role in scent communication during the breeding season. The loss of the ability to erect the spur and other unknown evolutionary forces acting in the echidna lineage resulted in the gradual decay of venom components and the evolution of a new role for the crural gland.

Should unstable extra-articular distal radial fractures be treated with fixed-angle volar-locked plates or percutaneous Kirschner wires? A prospective randomised controlled trial

Fractures of the distal radius are commonly treated with cast immobilisation; however, those potentially unstable injuries with dorsal comminution may need operative intervention. This intervention is usually with manipulation and Kirschner wires but advances in locking-plate technology have enabled surgeons to achieve anatomical reconstruction of complex fracture patterns, even in poor-quality osteoporotic bone.To ascertain if fixed-angle volar-locked plates confer a significant benefit over manipulation and Kirschner-wire stabilisation, we prospectively randomised 56 adult patients with isolated, closed,unilateral, unstable extra-articular fractures into two treatment groups, one fixed with K-wires and the other fixed with a volar locking plate.Functional outcomes were assessed using Gartland and Werley and Disabilities of the Arm, Shoulder and Hand (DASH) scores. These were statistically better in the plate group at 3 and 6 months.Radiological assessment showed statistically better results at 6 weeks, 3 months and 6 months, postoperatively.In the plate group, there was no significant loss of fracture reduction.

A double-blind, randomized placebo-controlled, phase II study of maintenance enzastaurin (ENZ) with 5-FU/leucovorin (LV) plus bevacizumab (BV) following first-line therapy for metastatic colorectal cancer (mCRC)

501

Background: Maintenance therapy is designed to maximize progression-free survival (PFS) and minimize toxicity in advanced CRC. ENZ is an oral serine/threonine kinase inhibitor that targets PKC-b and the AKT/PI3K pathway. Preclinical studies demonstrated synergistic antitumor effects when ENZ was combined with BV. In phase I studies, the combination was well tolerated. This phase II study assessed ENZ with 5-FU/LV plus BV as maintenance therapy for mCRC.

Methods: Patients had locally advanced or mCRC, and completed 6 cycles of first-line chemotherapy ≤4 wks prior to randomization. Arm A received a loading dose of ENZ 1,125 mg, followed by 500 mg/d subsequent doses. Arm B received placebo. Both groups received 5-FU/LV (LV 400 mg/m2 IV, 5-FU 400 mg/m2 bolus, 5-FU 2,400 mg/m2 IV) plus BV 5 mg/kg IV, every 2 wks. Patients were treated with 5-FU/LV plus BV plus either ENZ or placebo until disease progression or for 1 yr. Primary endpoint was PFS from randomization. Secondary endpoints were overall survival (OS) from randomization, and OS and PFS from start of first-line therapy. Analysis was done after 50 events (objective or clinical progression).

Results: 58 patients were randomized to Arm A (57 treated), 59 to Arm B (58 treated). 82 (70.1%) patients discontinued treatment (Arm A, 42 [72.4%]; Arm B, 40 [67.8%]), the majority due to disease progression. Median cycles were 9 in Arm A, 10 in Arm B. Median PFS in months was 5.8 in Arm A and 8.1 in Arm B (hazard ratio [HR]=1.35, 95% CI: 0.84, 2.16; protocol specified one-sided test, p=0.896). Median OS was not calculable due to high censoring (77.6% in Arm A and 91.5% in Arm B). Median PFS in months from start of first-line therapy was 8.9 in Arm A and 11.3 in Arm B (HR=1.39, 95% CI: 0.86, 2.23; one-sided, p=0.913). More patients developed thrombosis or embolism (TE), including pulmonary embolism, on Arm A (5 [8.8%] patients had grade 3 and 5 [8.8%] grade 4 TE) compared with Arm B (no grade 3 and 1 [1.7%] grade 4 TE).

Conclusions: ENZ did not demonstrate an advantage in PFS compared to BV-based therapy alone. Further development of maintenance therapy with ENZ is not recommended for mCRC.

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Phase II and pharmacogenomics study of enzastaurin plus temozolomide and radiation therapy in patients with glioblastoma multiforme or gliosarcoma

2020

Background: ENZ, an oral serine/threonine kinase inhibitor, suppresses signaling through PKCβ and the PI3K/AKT pathways to induce apoptosis, reduce proliferation, and suppress angiogenesis. The primary endpoint of this single-arm phase II trial was overall survival (OS). Secondary objectives included progression-free survival (PFS), safety, PK/PD, and patient-reported outcomes (PROs). A concurrent PGx project assessed the value of pretreatment molecular profiles as predictive of outcome. Magnetic resonance spectroscopy (MRS) was also evaluated during treatment for its value in predicting OS. Methods: Patients enrolled with newly diagnosed GBM/GS and KPS ≥60. Treatment started <5 weeks after diagnosis with RT 60 Gy given over 6 weeks and TMZ 75 mg/m2 given daily during RT and then at 200 mg/m2 from days 1–5 of a 28-day cycle. ENZ 250 mg/day was given daily during RT and adjuvantly. Planned treatment duration was 1 year. PGx parameters were: MGMT promoter methylation, mismatch repair status, PKC isoforms, pERK, pCREB, EGFR, PTEN, GSK3B, ser9, VEGF, and pS6. MRS was performed at baseline and at scheduled intervals. Changes in molecular signatures and imaging characteristics relative to survival were estimated using Kaplan-Meier and proportional hazards models. Analyses included phase I patients at ENZ 250 mg/day. Results: From September 2007 to November 2008, 60 phase II patients enrolled; 52 completed RT and eight are receiving RT. Of these, seven patients progressed immediately after RT and 17 progressed after one or more adjuvant cycles; five discontinued due to toxicity; four withdrew from trial. Treatment was well tolerated. The only toxicities seen in more than one-third of pateints were grade 1 fatigue, grade 1 nausea, and grade 1–2 lymphopenia. Grade 1 thrombocytopenia was seen in eight patients and grade 3 lymphopenia in five patients. OS, PFS, PROs, PGx, and imaging findings will be reported. Conclusions: The combination of ENZ plus TMZ during and following RT was well tolerated and may be an active regimen in GBM. This study represents the future of neuro-oncology clinical trial design by employing a novel multi-modal therapy while concurrently studying novel imaging and molecular techniques that may predict efficacy.

[Table: see text]

Phase I study of enzastaurin (ENZ) and bevacizumab (BV) in patients with advanced cancer: Safety, pharmacokinetics (PK), and response assessment

3517

Background: ENZ, an oral kinase inhibitor, suppresses tumor growth through PKC and PI-3 kinase/AKT. BV binds VEGF and inhibits angiogenesis. Since ENZ and BV are complementary in inhibiting angiogenesis, we conducted a Phase I study of ENZ / BV. Methods: Eligible patients (pts) had advanced cancer, adequate organ function and no co-morbidities for increased risk of drug-related toxicities. Six pts were enrolled per cohort; if ≤1 DLT the next cohort opened. A loading dose of ENZ 1125 mg was given on Day 1, C1. After 1 cohort combining ENZ 500 mg/QD and BV at 5mg/kg IV q 2 wks, subsequent cohorts alternated pts between BV 10 mg/kg IV q 2 wks and BV 15 mg/kg IV q 3wks with escalating doses of ENZ (500 mg/QD, 250 mg/BID, and 375 mg/BID) for a total of 7 cohorts. DLT was defined as C1: Grade (G)4 neutropenia ≥7 days, febrile neutropenia, G3 thrombocytopenia with bleeding or G4 thrombocytopenia; G3/G4 non-hematological toxicities, and toxicities associated with BV. ENZ PK was performed at steady-state on Day 1, C2. Results: 43 pts (21 with ovarian cancer) are evaluable for toxicity. Two DLTs (G3 elevated aminotransferase and intraparenchymal hemorrhage) occurred at different dose levels. No apparent increase in ENZ or BV toxicity was seen. Two SAEs (DVT and myocardial ischemia) in two pts occurred at DL 3 after 3 cycles and 13 cycles, respectively. Common toxicities included fatigue, chromaturia, dry/sore mouth, nausea and diarrhea. Nine of 43 pts (21%) had a response (CR, PR), 6 responses were in the ovarian subset (29%). Median time to progression was 3.9 mos (range 0–19.2 mos) and 7.7 mos for ovarian pts (range 0.3–19.2 mos). Overall, 43% remained on study without disease progression for >6 mos (51% of ovarian pts remained on study for >6 mos). Mean steady-state ENZ concentrations (%CV) at 500 mg/QD, 250mg/BID and 375mg/BID were 1080 nmol/L (82.8 %), 516 nmol/L (102%) and 1120 nmol/L (93.3%), respectively. Conclusions: The addition of ENZ to BV in any of the currently approved BV dosing schedules is well tolerated and clinically active in advanced cancer pts. ENZ exposures are highly variable and comparable across the three dose groups. The combination of ENZ / BV demonstrates encouraging activity, specifically in our population of ovarian cancer pts.

[Table: see text]