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.

[Table: see text]

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]

Phase I/II study of enzastaurin plus temozolomide during and following radiation therapy in patients with newly diagnosed glioblastoma multiforme (GBM) or gliosarcoma

12511

Background: Enzastaurin is a potent, selective, oral serine/threonine kinase inhibitor of PKCβ, an enzyme activated by vascular endothelial growth factor (VEGF). VEGF is upregulated in most cases of GBM, producing significant angiogenesis. This study combines the anti-angiogenic properties of enzastaurin with the current standard treatment of radiation therapy (RT) and cytotoxic chemotherapy (temozolomide; TMZ). Methods: A Phase 1/2 study of enzastaurin with TMZ during and following RT is ongoing in patients with newly diagnosed GBM. Two doses of enzastaurin will be evaluated during Phase 1. The first 6 patients will received 250 mg of enzastaurin daily. If no more than one patient experiences a dose-limiting toxicity (DLT) during RT and the first adjuvant cycle, an additional 6 patients will receive an escalated dose of 500 mg daily. The dose established in Phase 1 will be administered to 60 patients in Phase 2. The primary objective of Phase 2 is to determine the efficacy of enzastaurin as measured by overall survival. Multiple pharmacokinetic (PK) and pharmacodynamic (PD) endpoints will be evaluated using perfusion imaging and plasma biomarkers. Relevant growth factors and pathways will be analyzed in primary tumor tissue from each patient. Results: Since September 06, 6 patients have completed RT with concurrent enzastaurin (250 mg) and TMZ. None of these patients has experienced a DLT to date. It is expected that an additional 6 patients will be enrolled in January 07 and Phase 2 will start in May 2007. Conclusions: Enzastaurin with concurrent RT and TMZ appears safe. Final Phase 1 safety results and preliminary PK and PD data will be presented.

[Table: see text]

DNA as a dietary biomarker in Antarctic krill, Euphausia superba

The diet of Antarctic krill (Euphausia superba) has been studied using a variety of techniques, but current methods still suffer from problems that are difficult to solve. This study examined an alternative approach utilizing DNA as a prey biomarker. Methods were developed for the preservation, extraction, and identification of prey DNA from krill collected in the field. Group-specific polymerase chain reaction (PCR) was used to amplify diatom prey (Phylum: Bacillariophyta) and the results from DNA clone libraries were compared with microscopic diet analysis. DNA analysis was superior to microscopy for prey detection. However, differences in prey relative abundance estimates between the two techniques suggested some bias in the DNA-based estimates. Quantification showed that large amounts of prey DNA had been successfully preserved and extracted. Overall the results suggest that the application of DNA-based diet analysis to krill warrants further investigation, particularly for prey that are difficult to study using other methods.

Single-agent pemetrexed in patients with advanced and metastatic hepatoma

14064

Background: The incidence of hepatoma is rising in the United States, primarily due to the increase in the prevalence of hepatitis C. Surgical treatments are rarely an option for patients with advanced hepatoma, and while chemotherapy, particularly with doxorubicin-based regimens, has marginally prolonged survival, response rates have been poor with the burden of high toxicity. Pemetrexed, a folate antimetabolite, has demonstrated activity in hepatoma cell lines with a manageable toxicity profile, making it a potentially useful agent in hepatocellular carcinoma. Methods: A multicenter, Phase II study was conducted to assess the response rate and evaluate the toxicity profile of single-agent pemetrexed (ALIMTA) in first-line patients with advanced or metastatic hepatoma. Pemetrexed 600 mg/m2 IV was administered on Day 1 of each 21-day cycle until disease progression (PD). Patients were premedicated with dexamethasone 4 mg PO BID and received daily folic acid 350–1000 μg PO and Vitamin B12 1000 μg IM every 9 weeks. Results: This nonrandomized study employed Simon’s 2-stage design. There were 21 eligible patients enrolled in the first stage, and all 21 patients were enrolled within 4 months of trial opening. Median age was 72 years (range, 44–88), and most patients were white (62%) and male (81%). Ten percent (10%) had an ECOG PS of 2, 48% Stage IV disease, 52% prior surgery, and 33% tumors of unknown histological grade. The plan was to stop accrual if ≤2 responders were observed among the 21 patients. Of the 21 patients, 3 had SD, 2 had early toxicities (renal/liver failure, sepsis), 15 progressed, and 1 was noncompliant. The trial was closed due to lack of response. The most common Grade 3 hematological toxicities were neutropenia 6/21 (28.6%) and thrombocytopenia 3/21 (14.3%). One patient experienced both Grade 3 nausea and vomiting. There were no Grade 4 toxicities. There were 10 on-study deaths: 9 PD and 1 liver failure. None of the deaths were drug-related. The median actual survival was 2.5 months (range, <1–8). Conclusions: While pemetrexed was well tolerated in this patient population, it was not active. Most adverse events were related to disease state, not study treatment. Supported by Eli Lilly and Company, Indianapolis, IN

[Table: see text]

Phase I dose-escalating study of bi-weekly pemetrexed (MTA) with fixed dose rate gemcitabine (gem) in patients with advanced cancer

2049

Background: Fixed dose rate (FDR) gem may optimize the documented benefit of gem in pancreatic, NSCL, head and neck, and breast cancers. Preclinical data of the combination of MTA and gem indicate synergy. We studied a bi-weekly combination of MTA and FDR gem to improve tolerance over the previous “Day 1, 8” regimen. Methods: MTA followed by FDR gem infusion was given every 14 days in a dose-escalation design below. Dose-limiting toxicities (DLT) is defined as: grade 4 neutropenia ≥ 5 days, febrile neutropenia, grade 4 thrombocytopenia, or grade 3–4 non-hematological toxicities in 1st cycle. 27 patients were enrolled with median age 59 (range 41–82), males/females 18/9, and ECOG PS 0/1 (5/22). All received Vitamin B12 (1 mg IM prior to study & q9 weeks) and folic acid (350–1000 mcg po qd) supplementation 1–2 weeks prior and during study plus dexamethasone 4 mg po BID day before, of, and after chemotherapy. Results: Dose level 7 has been reached and is being expanded with DLT in 1 patient. Toxicities per patient during all cycles include grade 3–4 neutropenia (8/27 patients), grade 3 anemia (3), brief febrile neutropenia (6), grade 3 rash (1 patient), grade 3 low back pain (1), grade 3 renal failure (1), grade 5 perforated duodenal stent (1). In 19 patients evaluable for response, there were 11 stable disease and 8 progression of disease. Conclusion: Recommended phase II dose for bi-weekly MTA with FDR gem is likely to be 800 mg/m2 and 1,200 mg/m2 × 120 minutes. This regimen allows full doses and dose intensity of both drugs to be administered on a simple schedule with excellent tolerance. A phase II study in biliary cancer is planned. This study is supported in part by Eli Lilly.a This toxicity was at baseline, therefore not drug related.b, c These toxicities were in one patient and were not drug related, rather related to the individual patient’s status going into therapy.

[Table: see text]

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Phase I study of gemcitabine and cisplatin followed by pemetrexed and gemcitabine in patients with metastatic transitional cell carcinoma of the urothelium: Preliminary results

14550

Background: Pemetrexed has activity as a single agent and combined with gemcitabine (G) in platinum refractory metastatic urothelial cancer. The tolerability and activity of this new multi-targeted antifolate combined with standard platinum-based therapy is unknown. This Phase I multicenter trial was conducted in patients (pts) with metastatic TCC to determine the maximum tolerated dose (MTD) of G and cisplatin (C) followed by pemetrexed (P) and G. Methods: Cohorts of 3 to 6 pts were treated with escalating doses of G+C followed by P+G: Dose Level 0 -G+C (800+60 mg/m2) Day 1 and P+G (400+800 mg/m2) on Day 15; Dose Level I -G+C (800+70 mg/m2)/P+G (400+800 mg/m2); Dose Level II -G+C (1000+70 mg/m2)/P+G (400+1000 mg/m2); Dose Level III -G+C (1000+70 mg/m2)/P+G (500+1000 mg/m2) in a 28-day cycle. Pts received a maximum of 6 cycles of therapy; and all pts received folic acid and vitamin B12 supplements. The 3+3 standard Phase I escalation rule was used to establish the MTD. Results: A total of 10 pts have registered, 1 pt received only 1 dose and was replaced, and 9 have been treated: 3 at Dose Level 0 and 6 at Dose Level I. Of these 10 pts, 40% had Karnofsky PS of 100, and the median age was 68 years (range 58–82). One pt had a confirmed CR after 2 cycles, 1 pt at Dose Level I had a PR and received all 6 cycles, 6 pts did not finish treatment (4 pts due to toxicity and 2 pts due to PD), 1 pt at Dose Level I is continuing on therapy. Dose-limiting toxicity occurred in 2 pts at Dose Level I and included Grade 3–4 febrile neutropenia, pulmonary embolism, and diarrhea. The MTD of this triplet is Dose Level I, and the recommended Phase II dose (RP2D) is Dose Level 0. Patient accrual is continuing to further define toxicity at the RP2D. Conclusion: The addition of pemetrexed to standard gemcitabine and cisplatin as initial therapy for metastatic urothelial cancer is feasible. Toxicity of this triplet has been moderate. A Phase II trial is planned to determine the response rate, duration of response, TTP, time to treatment failure, and survival. Supported by Eli Lilly and Company, Indianapolis, IN

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Seasonal variations in reproductive hormones in free-ranging echidnas (Tachyglossus aculeatus): interaction between reproduction and hibernation

We measured the reproductive steroids testosterone and progesterone in free-ranging adult echidnas over several years. For months other than June-August, the mean progesterone concentration was 0.18+/-0.12 ng ml(-1) (n=14), and all blood samples taken from active female echidnas in June-August had progesterone concentrations above 0.5 ng ml(-1). The highest progesterone value measured was 13.4 ng ml(-1) in a pregnant female several days before egg-laying. For months other than June-August the mean testosterone concentration was 0.09+/-0.05 ng ml(-1) (n=13). During June-August all active sexually mature males had testosterone concentrations in excess of 0.2 ng ml(-1) and were found in mating groups at some time during this period. The highest plasma testosterone concentration measured was 4.62 ng ml(-1).

Diving behaviour, dive cycles and aerobic dive limit in the platypus Ornithorhynchus anatinus

We investigated the diving behaviour, the time allocation of the dive cycle and the behavioural aerobic dive limit (ADL) of platypuses (Ornithorhynchus anatinus) living at a sub-alpine Tasmanian lake. Individual platypuses were equipped with combined data logger-transmitter packages measuring dive depth. Mean dive duration was 31.3 s with 72% of all dives lasting between 18 and 40 s. Mean surface duration was 10.1 s. Mean dive depth was 1.28 m with a maximum of 8.77 m. Platypuses performed up to 1600 dives per foraging trip with a mean of 75 dives per hour. ADL was estimated by consideration of post-dive surface intervals vs. dive durations. Only 15% of all dives were found to exceed the estimated ADL of 40 s, indicating mainly aerobic diving in the species. Foraging platypuses followed a model of optimised recovery time, the optimal breathing theory. Total bottom duration or total foraging duration per day is proposed as a useful indicator of foraging efficiency and hence habitat quality in the species.

Control of breathing in the echidna (Tachyglossus aculeatus) during hibernation

Resting non-hibernating echidnas are characterised by low metabolic rates, but also have a very low respiratory frequency and a variable respiratory minute volume, often resulting in low levels of arterial O(2) and high CO(2). As the echidna lies at one physiological extreme among the hibernators, in terms of its large size and low metabolism and ventilatory requirement when not hibernating, a study of control of breathing during hibernation in echidnas should provide a useful test of the generality of various models. We used non-invasive techniques to study breathing patterns and the control of ventilation in 6 echidnas. Hibernating echidnas (T(b) range 7-10 degrees C) showed episodic breathing with bursts of breaths (average 36+/-16 breaths in 24+/-5 min) followed by a period of apnea (76+/-17 min) then a series (8+/-4) of slow breaths at 14+/-1 min intervals leading up to the next burst. Increasing CO(2) levels in the inspired air increased the number of breaths in a burst, eventually leading to continuous breathing. Inter burst breaths were controlled by O(2): hypoxia increased inter burst breaths, and decreased burst length, while hyperoxia abolished inter burst breaths and increased the apneic period. Overall, while CO(2) was a strong respiratory stimulus in hibernating echidnas, O(2) had little effect on total ventilation, but did have a strong effect on the breathing pattern.

The timing of hibernation in Tasmanian echidnas: why do they do it when they do?

We investigated the patterns of hibernation and arousals in seven free-ranging echidnas Tachyglossus aculeatus setosus (two male, five female) in Tasmania using implanted temperature data loggers. All echidnas showed a 'classical' pattern of mammalian hibernation, with bouts of deep torpor interrupted by periodic arousals to euthermia (mean duration 1.04+/-0.05 (n=146). Torpor bout length increased as body temperature fell during the hibernation season, and became more variable as temperature rose again. Hibernation started in late summer (February 28+/-5 days, n=6) and males aroused just before the winter solstice (June 15+/-3 days, n=3), females that subsequently produced young aroused 40 days later (July 25+/-3, n=4) while females that did not produce young hibernated for a further two months (arousal Sept 27+/-5, n=7). We suggest that hibernation in Tasmanian echidnas can be divided into two phases, the first phase, marked by declining minimum body temperatures as ambient temperature falls, appears to be obligatory for all animals, while the second phase is 'optional' and is utilised to varying amounts by females. We suggest that early arousal and breeding is the favoured option for females in good condition, and that the ability to completely omit breeding in some years, and hibernate through to spring is an adaptation to an uncertain climate.

Genetic differentiation in the Antarctic coastal krill Euphausia crystallorophias

The population genetics of the Antarctic neritic krill species Euphausia crystallorophias was examined by nucleotide sequence variation in its mitochondrial DNA. A 616 base pair region of the cytochrome c oxidase subunit I (COI) gene was screened for mutations by single-strand conformational polymorphism (SSCP) combined with restriction digestion. E. crystallorophias caught in three different regions of the Antarctic coastline were used--two samples from the Mertz Glacier Polynya and one sample each from the western side of the Antarctic Peninsula and from the Davis Sea. Significant genetic differences between krill samples were identified. However, the extent of these differences did not correlate with the degree of geographic separation between the sampling sites. This suggests that the genetic structuring may be the result of small-scale differentiation rather than differentiation between resident populations in separate parts of the Southern Ocean. The possibility that genetic differences between samples within a region are as important as differences between regions has implications for other studies of krill population genetics.

The relationship between health-related quality of life and weight loss

OBJECTIVE

This is a report of health-related quality of life (HRQOL) changes in obese patients completing at least 1 year of outpatient treatment in a weight reduction program combining phentermine-fenfluramine and dietary counseling.

RESEARCH METHODS AND PROCEDURES

Participants were 141 women (87.6%) and 20 men (12.4%) who had an average body mass index at intake of 41.1 kg/m(2) (SD = 7.0, range = 29.5 to 67.0 kg/m(2)) and an average age of 44.9 years (SD = 9.3, range = 23 to 65 years). HRQOL was assessed at intake and at 1-year follow-up using the Impact of Weight on Quality of Life (IWQOL)-Lite questionnaire. The relationship between HRQOL changes and weight loss was examined using Pearson correlations. Clinically meaningful change in HRQOL was defined as a 1.96 SEM reduction in IWQOL-Lite total score.

RESULTS

On average, participants lost 20.2 kg or 17.6% of their weight over the 1-year period. Of the participants, 15.5% lost <10% of their weight, 24.2% lost 10% to 14.9%, 23.6% lost 15% to 19.9%, and 36.6% lost 20% or more. All five IWQOL-Lite scales and total score showed statistically significant improvement over the 1-year period. Changes in IWQOL-Lite scores from intake to 1 year showed statistically significant correlations with percentage of weight loss for all subscales and total score. Subscale correlations with weight loss ranged from 0.166 (Public Distress) to 0.396 (Physical Function) and was 0.370 for the total score. Forty-four percent of participants losing <10% met the criterion of clinically meaningful change, compared with 51.3% losing 10% to 14.9%, 55.3% losing 15% to 19.95%, and 76.3% losing >20%. For total score and for three of the five IWQOL-Lite scales (Physical Function, Self-Esteem, and Sexual Life), the relationship between weight loss and clinically meaningful change was linear and was significant at p < 0.05. Physical Function and Self-Esteem were most strongly affected by weight loss.

DISCUSSION

HRQOL changes, as measured by an obesity-specific instrument (IWQOL-Lite), are strongly related to weight reduction.

Monotreme IGF2 expression and ancestral origin of genomic imprinting

IGF2 (insulin-like growth factor 2) and M6P/IGF2R (mannose 6-phosphate/insulin-like growth factor 2 receptor) are imprinted in marsupials and eutherians but not in birds. These results along with the absence of M6P/IGF2R imprinting in the egg-laying monotremes indicate that the parental imprinting of fetal growth-regulatory genes may be unique to viviparous mammals. In this investigation, we have cloned IGF2 from two monotreme mammals, the platypus and echidna, to further investigate the origin of imprinting. We report herein that like M6P/IGF2R, IGF2 is not imprinted in monotremes. Thus, although IGF2 encodes for a highly conserved growth factor in chordates, it is only imprinted in therian mammals. These findings support a concurrent origin of IGF2 and M6P/IGF2R imprinting in the late Jurassic/early Cretaceous period. The absence of imprinting in monotremes, despite apparent interparental conflicts over maternal-offspring exchange, argues that a fortuitous congruency of genetic and epigenetic events may have limited the phylogenetic breadth of genomic imprinting to therian mammals. J. Exp. Zool. (Mol. Dev. Evol.) 291:205-212, 2001.

Energetics of foraging and locomotion in the platypus Ornithorhynchus anatinus

We measured the energy requirements of platypuses foraging, diving and resting in a swim tank using flow-through respirometry. Also, walking metabolic rates were obtained from platypuses walking on a conventional treadmill. Energy requirements while foraging were found to depend on water temperature, body weight and dive duration and averaged 8.48 W kg(-1). Rates for subsurface swimming averaged 6.71 W kg(-1). Minimal cost of transport for subsurface swimming platypuses was 1.85 J N(-1)m(-1) at a speed of 0.4 m s(-1). Aerobic dive limit of the platypus amounted to 59 s. Metabolic rate of platypuses resting on the water surface was minimal with 3.91 W kg(-1) while minimal RMR on land was 2.08 W kg(-1). The metabolic rate for walking was 8.80 W kg(-1) and 10.56 W kg(-1) at speeds of 0.2 m s(-1) and 0.3 m s(-1), respectively. A formula was derived, which allows prediction of power requirements of platypuses in the wild from measurements of body weight, dive duration and water temperature. Platypuses were found to expend energy at only half the rate of semiaquatic eutherians of comparable body sizes during both walking and diving. However, costs of transport at optimal speed were in line with findings for eutherians. These patterns suggest that underwater locomotion of semiaquatic mammals have converged on very similar efficiencies despite differences in phylogeny and locomotor mode.

Antarctic krill (Euphausia superba) acquire a UV-absorbing mycosporine-like amino acid from dietary algae

We hypothesised that Antarctic krill acquire UV-absorbing mycosporine-like amino acids (MAAs) from dietary algae, which produce MAAs in response to ultraviolet (UV) irradiation. To test this hypothesis, we grew cultures of Phaeocystis antarctica that had been grown under either photosynthetically active radiation (PAR, 400-750 nm) plus UV irradiation (UVR, 280-400 nm), or else PAR-only. Algae grown under PAR-only produced high concentrations of porphyra-334, whereas additional UVR caused formation of high concentrations of mycosporine-glycine:valine and lower concentrations of porphyra-334. Krill were fed with either of these two cultures on eight occasions over 63 days. A third group was starved for the duration of the experiment. Animals were analysed after 36 and 63 days for MAA content. Remaining animals from all treatments were starved for a further 35 days and analysed to examine MAA retention characteristics. Our findings are that krill acquired different MAAs from dietary algae depending on the light conditions under which the algae were grown. Specifically, krill fed algae grown under PAR-only had higher concentrations of porphyra-334 than starved krill. Conversely, krill fed algae grown under PAR with additional UVR had high body concentrations of mycosporine-glycine:valine. MAA concentrations in starved krill remained static throughout the experiment. However, long term starvation (35 days) caused levels of certain acquired MAAs to decline. From this we can infer that MAA concentrations in krill are dependent on the MAA content of phytoplankton, and therefore the algae's response to UV exposure. This has implications for transfer of MAAs through marine trophic webs.

28S rDNA evolution in the Eumalacostraca and the phylogenetic position of krill

The Malacostraca are an ancient and morphologically diverse class of Crustacea. The phylogenetic position of one order within this class, the Euphausiacea ("krill," subclass Eumalacostraca) was investigated using 28S rDNA sequences from representatives of several malacostracan orders. Phylogenies for these sequences were estimated by maximum-likelihood and maximum-parsimony analysis. The results of these analyses produced a new scheme for evolution within the Eumalacostraca. The new phylogenies suggested that Euphausiacea are most closely related to the Mysida and not the Decapoda, as is generally thought. Furthermore, the Mysida were found not to be closely related to the Lophogastrida, which are often considered their sister taxon. These hypotheses were tested against the hypotheses of monophyly for the Eucarida, Mysidacea, and Peracarida and found to be significantly better on the basis of the 28S rDNA data.

Phase II trial of gemcitabine in patients with previously untreated metastatic cancer of the esophagus or gastroesophageal junction

BACKGROUND

There were approximately 12,500 cases of esophageal carcinoma diagnosed in the US in 1992 and 12,200 deaths. The impact of chemotherapy on patients with metastatic disease is marginal with a median survival of only five months. Gemcitabine (LY188011,2,2,-difluorodeoxycytidine: dFdC), an analog of cytosine arabinoside (ara-C), is a pyrimidine antimetabolite. Gemcitabine has shown interesting clinical activity in initial phase II clinical trials in a variety of malignancies, including the aerodigestive malignancies, squamous-cell carcinoma of the head/neck and both non-small-cell and small-cell lung cancer.

PATIENTS AND METHODS

A total of 21 patients with chemotherapy-naïve metastatic esophageal carcinoma were entered. Nineteen patients were evaluable for toxicity and seventeen patients were evaluable for response. Gemcitabine was administered intravenously at 1250 mg/m2 over 30-60 minutes on days 1, 8, and 15 followed by 1 week of rest. This four-week schedule defined a cycle of treatment. Patients may have received a maximum of six cycles.

RESULTS

Gemcitabine was well tolerated with minimal non-hematologic toxicity and grade 3-4 anemia, granulocytopenia, and thrombocytopenia occurring in 10.5%, 21%, and 0% of patients, respectively. No responses were seen in the seventeen evaluable patients.

CONCLUSIONS

At the dose and schedule studied it would appear that gemcitabine has no activity in patients with chemotherapy-naïve esophageal carcinoma.

Ocean circulation off east Antarctica affects ecosystem structure and sea-ice extent

Sea ice and oceanic boundaries have a dominant effect in structuring Antarctic marine ecosystems. Satellite imagery and historical data have identified the southern boundary of the Antarctic Circumpolar Current as a site of enhanced biological productivity. Meso-scale surveys off the Antarctic peninsula have related the abundances of Antarctic krill (Euphausia superba) and salps (Salpa thompsoni) to inter-annual variations in sea-ice extent. Here we have examined the ecosystem structure and oceanography spanning 3,500 km of the east Antarctic coastline, linking the scales of local surveys and global observations. Between 80 degrees and 150 degrees E there is a threefold variation in the extent of annual sea-ice cover, enabling us to examine the regional effects of sea ice and ocean circulation on biological productivity. Phytoplankton, primary productivity, Antarctic krill, whales and seabirds were concentrated where winter sea-ice extent is maximal, whereas salps were located where the sea-ice extent is minimal. We found enhanced biological activity south of the southern boundary of the Antarctic Circumpolar Current rather than in association with it. We propose that along this coastline ocean circulation determines both the sea-ice conditions and the level of biological productivity at all trophic levels.

Phase II trial of gemcitabine plus cisplatin in patients with metastatic urothelial cancer

PURPOSE

To assess the activity and toxicity of the combination of gemcitabine and cisplatin in the treatment of chemotherapy-naive patients with metastatic urothelial cancer.

PATIENTS AND METHODS

Forty-six patients with measurable stage IV carcinoma of the urothelium were enrolled onto this trial. Gemcitabine 1,000 mg/m(2) was administered intravenously for 30 to 60 minutes on days 1, 8, and 15 of each 28-day cycle. Cisplatin was administered after gemcitabine on day 1 of each cycle. The first 11 patients received an initial cisplatin dose of 100 mg/m(2). Due to the hematologic toxicity observed in several of these patients, the dose was reduced to 75 mg/m(2) in the remaining 35 patients. Patients were treated with six cycles, unless disease progression or severe toxicity necessitated earlier discontinuation.

RESULTS

Ten of the 46 patients achieved a complete response and nine showed a partial response. The overall response rate was 41%. The median time to treatment failure was 5.5 months. The median survival was 14.3 months, and the 1-year survival probability was 54%. Most of the toxicities were hematologic and, in general, easily manageable.

CONCLUSION

Gemcitabine plus cisplatin is active in the treatment of metastatic urothelial cancer in chemotherapy-naive patients and has an acceptable clinical safety profile. Studies are under way to further define the place of gemcitabine in combination with other chemotherapeutic agents in the treatment of metastatic urothelial cancer.

Descriptive study of the diaphragm and lungs in the short-nosed echidna, Tachyglossus aculeatus (Mammalia: monotremata)

In this descriptive study, we characterize the diaphragm and lungs of the short-nosed echidna, Tachyglossus aculeatus, using a combination of gross anatomical, light-microscopic, electron microscopic, and morphometric techniques, including airway casting. The diaphragm is inclined from ventro-cranial to dorso-caudal and possesses a large central tendon (centrum tendineum). The crural and costal muscle groups and the associated trigoni are located in the same positions as in other mammals. The bronchial branching pattern reveals cranially broad, tapering stem bronchi and an unusually small number of first order bronchi. The asymmetrical primary branching pattern and possibly also the asymmetry of right and left lungs are plesiomorphic within the Mammalia. The histology and ultrastructure of the airways and lung parenchyma reveal no unusual features: alveolar type 1 and type 2 cells in the parenchyma; type 2 cells, exocrine bronchiolar cells (Clara cells), ciliated cells, and goblet cells in the terminal airways and the latter two cell types in the bronchi. Both a double and a single capillary net are found on the interalveolar septa. The high capillary loading of the double net may be of selective advantage because of long apneas and low metabolic rate in the echidna.