Seasonal variation in male alternative reproductive tactics.

Genetic parentage analyses reveal considerable diversity in alternative reproductive behaviours (e.g. sneaking) in many taxa. However, little is known about whether these behaviours vary seasonally and between populations. Here, we investigate seasonal variation in male reproductive behaviours in a population of two-spotted gobies (Gobiusculus flavescens) in Norway. Male two-spotted gobies guard nests, attract females and care for fertilized eggs. We collected clutches and nest-guarding males early and late in the breeding season in artificial nests and used microsatellite markers to reconstruct parentage from a subset of offspring from each nest. We hypothesized that mating, reproductive success and sneaking should be more prevalent early in the breeding season when competition for mates among males is predicted to be higher. However, parentage analyses revealed similar values of mating, reproductive success and high frequencies of successful sneaking early (30% of nests) and late (27% of nests) in the season. We also found that multiple females with eggs in the same nest were fertilized by one or more sneaker males, indicating that some males in this population engage in a satellite strategy. We contrast our results to previous work that demonstrates low levels of cuckoldry in a population in Sweden. Our results demonstrate marked stability in both the genetic mating system and male alternative reproductive tactics over the breeding season. However, sneaking rates may vary geographically within a species, likely due to local selection influencing ecological factors encountered at different locations.

Mate competition and resource competition are inter-related in sexual selection.

Sexual selection can be affected by the competition for limited breeding resources and/or the competition for limited mates. Although there is ample evidence for each type of competition by itself, little is known about their relative importance and interaction. To address these questions, we established 48 experimental breeding populations of the two-spotted goby (Gobiusculus flavescens), a substrate-breeding fish with paternal care. In three experimental treatments, males were limited in the access to either nest sites or mates or were provided with both nests and mates in excess. We quantified male competition behaviour (agonistic and courtship), the opportunity for selection and selection on male body size. Limited access to nests and mates produced similar opportunities for selection, but only limited access to mates increased male competitive behaviours and caused positive selection on male body size. Selection on body size in the mate-limited treatment was due both to larger males being more likely to take up nests and to larger males being more likely to mate once they had a nest. These findings demonstrate that resource and mate limitation can differ in their effects on sexual selection. The results also reveal that resource and mating competition can be highly inter-related and not always separated in time, implying that methods to disentangle the two processes must be chosen with care. Future research should consider experimental and analytical approaches similar to those of the present study in attempts to elucidate the interaction of resource and mating competition in animals.

Large males fight and court more across a range of social environments: an experiment on the two spotted goby Gobiusculus flavescens.

The present study explored how male size relates to mating competition across a natural range of male and female densities in the two-spotted goby Gobiusculus flavescens. Across this range of social environments, large males were more than twice as likely as small ones to chase other males, to become nest-holders, and to court females, but large males were not significantly more likely to engage in agonistic fin displays. Overall, the study showed that large males court and fight more than small ones across a wide, yet natural, span of social environments. Having a large body size appears to confer competitive advantage for males in any social environment of the study species. Further studies are needed to disentangle whether the benefit of large size is mainly in competition over resources, over matings as such, or both.

Vinorelbine and gemcitabine vs vinorelbine and carboplatin as first-line treatment of advanced NSCLC. A phase III randomised controlled trial by the Norwegian Lung Cancer Study Group.

BACKGROUND: Platinum-based doublet chemotherapy is the standard first-line treatment for advanced non-small cell lung cancer (NSCLC), but earlier studies have suggested that non-platinum combinations are equally effective and better tolerated. We conducted a national, randomised study to compare a non-platinum with a platinum combination. METHODS: Eligible patients had stage IIIB/IV NSCLC and performance status (PS) 0-2. Patients received up to three cycles of vinorelbine 60 mg m(-2) p.o.+gemcitabine 1000 mg m(-2) i.v. day 1 and 8 (VG) or vinorelbine 60 mg m(-2) p.o. day 1 and 8+carboplatin area under the curve=5 (Calvert's formula) i.v. day 1 (VC). Patients ≥75 years received 75% of the dose. Endpoints were overall survival, health-related quality of life (HRQoL), toxicity, and the use of radiotherapy. RESULTS: We randomised 444 patients from September 2007 to April 2009. The median age was 65 years, 58% were men and 25% had PS 2. Median survival was VG: 6.3 months; VC: 7.0 months, P=0.802. Vinorelbine plus carboplatin patients had more grade III/IV nausea/vomiting (VG: 4%, VC: 12%, P=0.008) and grade IV neutropenia (VG: 7%, VC: 19%, P<0.001). Infections, HRQoL and the use of radiotherapy did not differ significantly between the treatment groups. CONCLUSION: The two regimens yielded similar overall survival. The VG combination had only a slightly better toxicity profile.

A novel in vivo method for lung segment movement tracking.

Knowledge about lung movement in health and disease is sparse. Current evaluation methods, such as CT, MRI and external view have significant limitations. To study respiratory movement for image guided tumour diagnostics and respiratory physiology, we needed a method that overcomes these limitations.We fitted balloon catheters with electromagnetic sensors, and placed them in lung lobes of ventilated pigs. The sensors sensed their position at 40 Hz in an electromagnetic tracking field with a precision of ∼0.5 mm. The method was evaluated by recording sensor movement in different body positions and at different tidal volumes. No 'gold standard' exists for lung segment tracking, so our results were compared to 'common knowledge'. The sensors were easily placed, showed no clinically relevant position drift and yielded sub-millimetre accuracy. Our measurements fit 'common knowledge', as increased ventilation volume increased respiratory movement, and the right lung moved significantly less in the right than the left lateral position. The novel method for tracking lung segment movements during respiration was easy to implement and yielded high spatial and temporal resolution, and the equipment parts are reusable. It is easy to implement as a research tool for lung physiology, navigated bronchoscopy and radiation therapy.

First record of a Kabatana sp. microsporidium infecting fish in the Atlantic Ocean.

Two-spotted goby Gobiusculus flavescens from the Swedish Gullmarsfjord regularly present subcutaneous creamy-white patches in the body musculature, associated with Kabatana sp. infection. Analysis of the 16S rRNA gene of the microsporidium showed 98.54% homology with Kabatana newberryi infecting a marine goby from California, indicating that the Swedish microsporidium is either a different strain of K. newberryi or a closely related species. This represents the first record of a Kabatana species in the Atlantic Ocean. The genetic similarity of the 2 microsporidia was paralleled by close infection phenotypes. Infected muscle fibres were swollen compared to adjacent non-infected fibres, and mature spore masses were found throughout the skeletal musculature. No xenoma formation was detected. Since G. flavescens is an established model species in behavioural ecology, the host-parasite system is ideally suited for testing how microsporidian infections affect host behaviour and fitness.

Female ornamentation and egg carotenoids of six sympatric gobies.

Belly colouration, gonad carotenoid concentration and skin transparency were quantified in gravid Gobiusculus flavescens, as well as in females of five sympatric gobies where belly ornamentation has not been described. Although G. flavescens females did, indeed, have far more colourful bellies than the other species, this could only in part be explained by a high concentration of total gonad carotenoids. Comparable, or occasionally higher, carotenoid levels were found in the gonads of other species. Instead, the unusual ornamentation of G. flavescens arises from a unique combination of carotenoid-rich gonads and a highly transparent abdominal skin.

Male mate choice selects for female coloration in a fish.

Although sexual selection theory has proved successful in explaining a wide array of male ornaments, the function of ornaments occurring in females is largely unknown. Traditionally, female ornaments have been considered nonfunctional, being merely a genetically correlated response to selection for male ornamentation. However, this hypothesis is only relevant to species in which the ornament is basically the same in the two sexes. Alternatively, female ornaments may be influenced by selection acting directly on the females, either through female-female competition or male choice. We tested the latter hypothesis in mate-choice experiments with two-spotted gobies (Gobiusculus flavescens). In this small marine fish, females have bright yellow-orange bellies during the breeding season, a conspicuous trait that is not present in males. We conducted two aquarium experiments to test whether males preferred to mate with more colorful females. In the first experiment, males had a choice between two females that varied in natural coloration (and belly roundness). In the second experiment, we manipulated belly coloration and kept roundness constant. Males spent more time with colorful than with drab females in both experiments and also performed far more courtship displays toward colorful females. Our study provides experimental evidence that males prefer ornamented females in a fish that is not sex-role reversed, supporting the hypothesis that female ornamentation is sexually selected.

Analysis of contrast-enhanced dynamic MR images of the lung.

Recent studies have demonstrated the potential of dynamic contrast-enhanced magnetic resonance imaging (MRI) describing pulmonary perfusion. However, breathing motion, susceptibility artifacts, and a low signal-to-noise ratio (SNR) make automatic pixel-by-pixel analysis difficult. In the present work, we propose a novel method to compensate for breathing motion. In order to test the feasibility of this method, we enrolled 53 patients with pulmonary embolism (N = 24), chronic obstructive pulmonary disease (COPD) (N = 14), and acute pneumonia (N = 15). A crucial part of the method, an automatic diaphragm detection algorithm, was evaluated in all 53 patients by two independent observers. The accuracy of the method to detect the diaphragm showed a success rate of 92%. Furthermore, a Bayesian noise reduction technique was implemented and tested. This technique significantly reduced the noise level without removing important clinical information. In conclusion, the combination of a motion correction method and a Bayesian noise reduction method offered a rapid, semiautomatic pixel-by-pixel analysis of the lungs with great potential for research and clinical use.

Microsurgical decompression without laminectomy in lumbar spinal stenosis.

Our objectives were to study a/ the clinical results of microsurgical decompression without laminectomy compared to those reported from standard decompression laminectomy in patients with central lumbar spinal stenosis, and b/ if the microsurgical technique could prevent post-operative instability and concomitant symptoms. Twenty-one patients were treated, 11 men and 10 women, aged 47-81 years. Fourteen patients had "pure" stenosis whereas 7 had additional diseases that compounded the symptoms of stenosis. Independent examiners saw the patients pre-operatively and a mean of 27 months post-operatively. Plain X-ray films were taken of 14 patients a mean of 5 years post-operatively to study possible slippage. Among the 14 patients with "pure" stenosis the results were excellent in 13 and fair in 1. Among the 7 with additional diseases the outcome was excellent in 1, fair in 1, unchanged in 3 and worse in 2. The technique did not prevent post-operative slippage, which occurred in 3 of 14 patients. However, the clinical outcome was not related to slippage. We found the microsurgical technique safe and gentle with excellent possibilities for decompression of the complete spinal canal without laminectomy. The results following this procedure were well comparable to or even better than those reported following standard decompression laminectomy.

Perfusion magnetic resonance imaging of the lung: characterization of pneumonia and chronic obstructive pulmonary disease. A feasibility study.

Perfusion magnetic resonance (MR) imaging is a promising new method for detection of perfusion defects in the diagnosis of pulmonary embolism. In the present study we evaluated the first-pass characteristics of perfusion MR imaging in patients with pneumonia or chronic obstructive pulmonary disease (COPD), frequent differential diagnoses to pulmonary embolism. Dynamic contrast-enhanced MR images of 12 patients with acute pneumonia and 13 patients with exacerbation of COPD were acquired in both the coronal and transaxial planes (an inversion recovery prepared gradient-echo sequence using 0.05 mmol/kg gadodiamide/injection). The MR images and the signal intensity (SI) versus time curves were characterized for each disease entity and compared with normal lung and the findings in pulmonary embolism from our previous study. The perfusion MR images of pneumonia showed distinct regions of increased contrast enhancement; in COPD with signs of emphysema (11 of the 13 COPD patients), the images showed a coarse pattern of reduced contrast enhancement. The SI versus time curves of pneumonia, COPD with signs of emphysema, and normal lung were statistically different, the respective pooled SI values (+/-95% CI) being as follows: mean baseline SI, 20.7 (1.1), 7.4 (0.4), and 8.5 (0.3); mean peak SI, no peak, 12.9 (1.5), and 27 (4.6); and mean max change of SI in percent, 110 (27), 79 (22), and 205 (52). Perfusion MR imaging of pneumonia and COPD with signs of emphysema showed first-pass that were characteristics promising for diagnostic use. Both the MR images and the SI versus time curves were different from the perfusion characteristics in normal lung and pulmonary embolism shown previously.

Lumbar spinal stenosis: conservative or surgical management?: A prospective 10-year study.

STUDY DESIGN: A cohort of 100 patients with symptomatic lumbar spinal stenosis, characterized in a previous article, were given surgical or conservative treatment and followed for 10 years. OBJECTIVES: To identify the short- and long-term results after surgical and conservative treatment, and to determine whether clinical or radiologic predictors for the treatment result can be defined. SUMMARY OF BACKGROUND DATA: Surgical decompression has been considered the rational treatment. However, clinical experience indicates that many patients do well with conservative treatment. METHODS: In this study, 19 patients with severe symptoms were selected for surgical treatment and 50 patients with moderate symptoms for conservative treatment, whereas 31 patients were randomized between the conservative (n = 18) and surgical (n = 13) treatment groups. Pain was decisive for the choice of treatment group. All patients were observed for 10 years by clinical evaluation and questionnaires. The results, evaluated by patient and physician, were rated as excellent, fair, unchanged, or worse. RESULTS: After a period of 3 months, relief of pain had occurred in most patients. Some had relief earlier, whereas for others it took 1 year. After a period of 4 years, excellent or fair results were found in half of the patients selected for conservative treatment, and in four fifths of the patients selected for surgery. Patients with an unsatisfactory result from conservative treatment were offered delayed surgery after 3 to 27 months (median, 3.5 months). The treatment result of delayed surgery was essentially similar to that of the initial group. The treatment result for the patients randomized for surgical treatment was considerably better than for the patients randomized for conservative treatment. Clinically significant deterioration of symptoms during the final 6 years of the follow-up period was not observed. Patients with multilevel afflictions, surgically treated or not, did not have a poorer outcome than those with single-level afflictions. Clinical or radiologic predictors for the final outcome were not found. There were no dropouts, except for 14 deaths. CONCLUSIONS: The outcome was most favorable for surgical treatment. However, an initial conservative approach seems advisable for many patients because those with an unsatisfactory result can be treated surgically later with a good outcome.

[Pulmonary embolism among young non-pregnant women]. / Lungeemboli blant yngre ikke-gravide kvinner.

This study focuses on the incidence and risk profile among young women with a diagnosis of pulmonary embolism over the 10-year period 1988-97. A total of 66 non-pregnant women aged 15-44, treated for the first event of pulmonary embolism, were identified by discharge diagnosis at two main Norwegian hospitals (The Regional Hospital of Trondheim and Ullevål Hospital, Oslo). The estimated overall incidence of pulmonary embolism was 6.8 per 100,000 women-years. The crude incidence decreased from 7.5 per 100,000 women-years in 1988-90 to 4.1 per 100,000 women-years in 1996-97 (p < 0.1). 25 (38%) of the 66 patients were identified with at least one medical risk factor, four patients (6%) with a family history of thrombophilia and 30 patients (45%) used oral contraceptives (OC) at the time of diagnosis. 25 (68%) of the 37 patients without registered risk factors used OC. The incidence of pulmonary embolism decreased during the 10-year period, with unchanged risk profile. Two women (3%) died from pulmonary emboli shorter than three weeks after onset of symptoms.

[Deep venous thrombosis in young women in Norway]. / Dyp venetrombose hos yngre kvinner i Norge.

The incidence and distribution of risk factors in non-pregnant women diagnosed with deep vein thrombosis is not well known and was the target of the present study. The medical records of 102 non-pregnant women aged 15-44 hospitalized with deep vein thrombosis at two major Norwegian hospitals were examined retrospectively. The overall incidence of first event of deep vein thrombosis remained fairly constant over the 10-year study period and was estimated at 10.5 per 100,000 women-years. The incidence increased with age and was found twice as high for women 35-44 years of age when compared with the 15-34 age group. Forty-three (42%) of the patients had no identifiable risk factors. Surgery or trauma was found in 37 (36%) of the patients, eight (8%) had a diagnosis of associated cancer, and five (5%) were drug addicts. Five of eight patients registered with immobilization had immobilizing chronic neurological diseases. Thirty-nine (38%) of the patients used oral contraceptives at the time of diagnosis, and 14 of the 39 users of oral contraceptives were identified with medical risk factors. Over the 10-year study period there was no change in the incidence of venous thromboembolism and the risk profile among cases remained constant.

[Reporting of adverse drug reactions to the Norwegian Drug Control Agency]. / Rapportering av legemiddelinduserte helseskadar til Statens legemiddelkontroll.

This article reports on a retrospective study in two major Norwegian hospitals of spontaneous reporting to the Adverse Drug Reaction Committee of the Norwegian Medicines Control Agency of adverse reactions from the use of oral contraceptives (OCs) among patients with a diagnosis of venous thromboembolism. In these two hospitals, 168 women between 15 and 44 were diagnosed with a first event of venous thromboembolism during the ten-year period up to the end og 1997; 69 of them were OC users at the time of diagnosis. Three medical records (4%) kept at the hospital contained information on a report of adverse drug reaction to the Norwegian Medicines Control Agency. The Agency's database of all spontaneous reports on adverse drug reactions contains 112 reports of venous thromboembolism in the context of OC use. These reports came from all over Norway during the ten-year period of our study; four of the reports came from the study hospitals. We conclude that venous thromboembolism during the use of OCs was underreported by more than 90%. This corresponds to estimates of underreporting of other adverse drug reactions from the use of various compounds, in Norway as well as in other countries.

A closed-chest pulmonary artery occlusion/reperfusion model in the pig: detection of experimental pulmonary embolism with MR angiography and perfusion MR imaging.

RATIONALE AND OBJECTIVES: To establish a pig model suitable for imitating pulmonary emboli to facilitate research in the diagnosis of pulmonary embolism. METHODS: Thirteen animals were anesthetized, mechanically ventilated, and subjected to pulmonary artery catheterization initiated from the right external jugular vein. With the use of a Swan-Ganz catheter, repetitive occlusion/reperfusion maneuvers were done at different locations of the pulmonary arterial tree. Conventional pulmonary angiography, MR angiography, and perfusion MR imaging were performed. RESULTS: The model remained hemodynamically stable throughout the 13 experiments, without any significant difference between the blood pressure measurements at the start and at the end of the right-heart and pulmonary artery catheterizations. In each of the nine animal experiments that investigated MR imaging, four of four using perfusion MR imaging (proximal and distal occlusions) and five of five using MR angiography (larger pulmonary artery occlusions), all repeated pulmonary artery occlusions were successfully performed (reproducibility of 100%). CONCLUSIONS: The closed-chest pulmonary artery occlusion/reperfusion model in the pig allowed repetitive, controlled imitations of pulmonary emboli at different levels of the pulmonary artery in the same experiment. MR angiography and perfusion MR imaging were adequate to detect the pulmonary artery occlusions and the nonperfused lung regions, respectively. The model may be a helpful tool for future research in this field.

Why are female birds ornamented?

Sexual selection is now widely accepted as the main evolutionary explanation of extravagant male ornaments. By contrast, ornaments occurring in females have received little attention and often have been considered as nonadaptive, correlated effects of selection on males. However, recent comparative evidence suggests that female ornaments have evolved quite independently of male showiness. Also, new theoretical models predict that both male mate choice and female contest competition will occur under certain circumstances. This is supported by recent experimental studies. Thus, selection acting on females might be a widespread cause of female ornaments.

Colour bands, mate choice and paternity in the bluethroat.

Studies of several bird species have shown that coloured leg bands may affect a male's success in mate attraction and/or mating competition. From a colour band experiment in the field, we have previously reported that male bluethroats, Luscinia s. svecica, with blue and orange bands (BO males) guarded their mates less intensely at the peak of female fertility, and spent more time advertising for additional mates, than males banded with non-BO colours. These responses indicated that BO males experienced less threat to their paternity than did non-BO males, possibly mediated through an increased attractiveness. Here we present paternity analyses of the broods from the field study and test whether there were differences between the two male groups in within-pair or extrapair paternity. There were no significant differences between the two groups of males in paternity, suggesting effective male protection of paternity. However, extrapair paternity was infrequent in the 2 years of the field experiment; hence, the power in detecting effects on paternity does not allow a definitive conclusion on this issue. We also conducted an aviary experiment in which females were given the choice between a BO male and a non-BO male, to test whether females had preferences for particular colour bands. Females did not associate more with BO males, as would have been expected if these males were more attractive in social mate choice. Our results suggest that the effects of colour bands on social mate choice and paternity are, at best, weak. Copyright 2000 The Association for the Study of Animal Behaviour.

Contrast-enhanced pulmonary MR imaging.

The present paper reports our own experience with MR perfusion imaging and gives an overview of contrast-enhanced pulmonary MR perfusion imaging, MR angiography, and ventilation MR imaging using hyperpolarized gases or oxygen as contrast agent. These methods are discussed within the context of their possible role in the diagnosis of pulmonary diseases, particularly embolism and emphysema.

[Lumbar disk prolapses and radiological spinal intervention. What do the randomized controlled trials say?]. / Lumbale skiveprolapser og radiologisk ryggintervensjon. Hva sier randomiserte kontrollerte studier?

We searched the Medline database and examined 11 randomized controlled trials to evaluate the efficacy of treating lumbar herniated discs by injection with chymopapain or by automated percutaneous discectomy. Our findings show that chemonucleolysis with chymopapain is a documented treatment which is better than placebo, but consistently inferior to surgical discectomy. The two randomized controlled trials to evaluate automated percutaneous discectomy fail to show efficacy that is any better than would be expected from a placebo response. We conclude that surgical discectomy is the best treatment option for a herniated disc when conservative efforts have failed.