Importance of patellofemoral and tibiofemoral cartilage lesions on trajectory of self-reported outcomes in patients at high risk of knee OA: 4-6 years follow-up of patients undergoing meniscal surgery.

OBJECTIVE: We evaluated whether patient-reported outcome trajectories (i.e., changes over time) differed by intraoperative compartmental cartilage lesion pattern over 4-6 years following arthroscopic meniscal surgery. METHODS: In this ancillary study of the Knee Arthroscopy Cohort Southern Denmark cohort, we intraoperatively categorized cartilage lesions as isolated patellofemoral, isolated tibiofemoral, or combined patellofemoral/tibiofemoral. Participants completed the Knee injury and Osteoarthritis Outcome Score (KOOS) pre-operatively, at 3 and 12 months, and at 4-6 years post-operatively and reported overall satisfaction at final follow-up. Our main outcome was KOOS4 (grand mean of four subscale means). We evaluated whether KOOS4 scores changed over time according to cartilage lesion patterns using adjusted mixed linear regression. We also estimated probability of treatment satisfaction using logistic regression. RESULTS: Of 630 participants with complete cartilage scores, 280 (44%) were women, mean (standard deviation) age was 49 (13) years, and BMI was 27.3 (4.4) kg/m2. KOOS4 scores at baseline were slightly lower in all lesion groups compared to the no lesion group, yet only the combined group was statistically significantly lower. KOOS4 trajectories were similar across cartilage lesion patterns, but by final follow-up, adjusted mean KOOS4 scores were 6.8 (95% CI 2.2, 11.4) to 9.8 (1.1, 18.5) points lower in groups with cartilage lesions compared to the no lesion group. Probability of patient-reported satisfaction did not differ statistically by group. CONCLUSIONS: Though KOOS4 scores were slightly lower in groups with arthroscopically assessed cartilage lesions compared to the no lesion group, trajectories were similar across all groups.

Laminar airflow decreases microbial air contamination compared with turbulent ventilated operating theatres during live total joint arthroplasty: a nationwide survey.

BACKGROUND: Preventing surgical site infections and prosthetic joint infections is crucial for patient safety after total joint arthroplasty. Microbial air contamination has been suggested as a risk factor. Therefore, the ventilation system that will reduce air contamination most effectively in operating theatres (OTs) has been discussed. AIM: To determine whether laminar airflow (LAF) ventilation is superior to turbulent airflow (TAF) ventilation by looking at the colony forming units (cfu) count during live total hip and knee arthroplasties. Furthermore, to explore whether the number of OT personnel, door and cabinet lock openings and technical parameters of the ventilation systems have an impact on the number of cfu. METHODS: Active air sampling and passive sedimented bacterial load were performed in 17 OTs, equipped with either LAF or TAF ventilation, during 51 live surgeries while observations were noted. FINDINGS: LAF OTs reduced cfu counts compared with TAF OTs during live surgery (P<0.001). All LAF OTs provided ultraclean air whereas TAF had nine procedures exceeding the threshold of 10 cfu/m3. Door and cabinet lock openings and number of personnel did not influence the cfu count, while it decreased with increasing volume and total air change per hour (P<0.05). CONCLUSION: All LAF OTs had cfu counts within recommendations and provided lower cfu counts compared with TAF OTs. The number of OT personnel and total openings did not have an influence on cfu counts. Increased volume of the OT and total air change per hour showed a decrease in active cfu counts.

From clear lakes to murky waters - tracing the functional response of high-latitude lake communities to concurrent 'greening' and 'browning'.

Climate change and the intensification of land use practices are causing widespread eutrophication of subarctic lakes. The implications of this rapid change for lake ecosystem function remain poorly understood. To assess how freshwater communities respond to such profound changes in their habitat and resource availability, we conducted a space-for-time analysis of food-web structure in 30 lakes situated across a temperature-productivity gradient equivalent to the predicted future climate of subarctic Europe (temperature +3°C, precipitation +30% and nutrient +45 µg L-1 total phosphorus). Along this gradient, we observed an increase in the assimilation of pelagic-derived carbon from 25 to 75% throughout primary, secondary and tertiary consumers. This shift was overwhelmingly driven by the consumption of pelagic detritus by benthic primary consumers and was not accompanied by increased pelagic foraging by higher trophic level consumers. Our data also revealed a convergence of the carbon isotope ratios of pelagic and benthic food web endmembers in the warmest, most productive lakes indicating that the incorporation of terrestrial derived carbon into aquatic food webs increases as land use intensifies. These results, reflecting changes along a gradient characteristic of the predicted future environment throughout the subarctic, indicate that climate and land use driven eutrophication and browning are radically altering the function and fuelling of aquatic food webs in this biome.

Determinants of parasite distribution in Arctic charr populations: catchment structure versus dispersal potential.

Parasite distribution patterns in lotic catchments are driven by the combined influences of unidirectional water flow and the mobility of the most mobile host. However, the importance of such drivers in catchments dominated by lentic habitats are poorly understood. We examined parasite populations of Arctic charr Salvelinus alpinus from a series of linear-connected lakes in northern Norway to assess the generality of lotic-derived catchment-scale parasite assemblage patterns. Our results demonstrated that the abundance of most parasite taxa increased from the upper to lower catchment. Allogenic taxa (piscivorous birds as final host) were present throughout the entire catchment, whereas their autogenic counterparts (charr as final hosts) demonstrated restricted distributions, thus supporting the theory that the mobility of the most mobile host determines taxa-specific parasite distribution patterns. Overall, catchment-wide parasite abundance and distribution patterns in this lentic-dominated system were in accordance with those reported for lotic systems. Additionally, our study highlighted that upper catchment regions may be inadequate reservoirs to facilitate recolonization of parasite communities in the event of downstream environmental perturbations.

Histopathological characterisation of retinal lesions associated to Diplostomum species (Platyhelminthes: Trematoda) infection in polymorphic Arctic charr Salvelinus alpinus.

The eye represents an immune privileged organ where parasites can escape host reactions. This study provides the first systematic evidence of the pathology associated with Diplostomum sp. infection in the eye retina of fish (i.e. Arctic charr). Histological sections showed that the trematodes caused mechanical disengagement between the retinal pigmentary epithelium and the neurosensory retina, with damaged cones and rods in the outer segment and epithelium reduced to a single layer of pigmentary cells. The metacercariae were "floating" in possibly fluid-filled vesicles together with several round cells, mostly located in the anterio-dorsal and anterio-ventral areas of the eye near the iris. The round cells may indicate internal retinal damage repair mechanisms, without connections to the general immune system. Metacercariae intestines contained pigmented cellular debris indicating that they feed on retinal epithelium. These retinal lesions may have similar vision effects as focal retinal detachment in vertebrates. Diplostomum metacercaria alters fish visual acuity but may in a lesser degree lead to a severe or total visual impairment because of repairing mechanisms. The pathology in the retina seems thereby to be dependent on fish size, age and dose.

Are hybrids between Atlantic salmon and brown trout suitable long-term hosts of Gyrodactylus salaris during winter?

The monogenean parasite Gyrodactylus salaris poses serious threats to many Atlantic salmon populations and presents many conservation and management questions/foci and challenges. It is therefore critical to identify potential vectors for infection. To test whether hybrids of native Atlantic salmon (Salmo salar) × brown trout (Salmo trutta) are suitable as reservoir hosts for G. salaris during winter, infected hybrid parr were released into a natural subarctic brook in the autumn. Six months later, 23.9% of the pit-tagged fish were recaptured. During the experimental period, the hybrids had a sixfold increase in mean intensity of G. salaris, while the prevalence decreased from 81% to 35%. There was high interindividual hybrid variability in susceptibility to infections. The maximum infrapopulation growth rate (0.018 day-1 ) of G. salaris throughout the winter was comparable to earlier laboratory experiments at similar temperatures. The results confirm that infrapopulations of G. salaris may reproduce on a hybrid population for several generations at low water temperatures (~1 °C). Wild salmon-trout hybrids are undoubtedly susceptible to G. salaris and represent an important reservoir host for the parasite independent of other co-occurring susceptible hosts. Consequently, these hybrids may pose a serious risk for G. salaris transmission to nearby, uninfected rivers by migratory individuals.

A simplified method to estimate Diphyllobothrium spp. infection in salmonids.

Some fish parasites constitute severe management problems as they may cause mortality of their fish host or are important zoonoses of humans. Parasite assessments are therefore critical to keep track of infections. If conventional sampling techniques can be simplified, parasite assessments might be easier to obtain, less time-consuming and more extensive. In this study, we compare the assessed number of Diphyllobothrium spp. cysts (CYST) with the counted number of Diphyllobothrium spp. plerocercoid larvae recovered using a conventional digestive technique (LARV). The aim was to determine the potential of using CYST as a simplified methodology for assessing Diphyllobothrium spp. infection in salmonids. In total, 365 brown trout and 424 Arctic charr were sampled from nine lakes in subarctic Norway. Strong correlation, significant linear relationship and large amount of explained variation were found between log10 CYST and log10 LARV in both fish species. The method had a slight, but not significant tendency to work better in charr compared to trout. In addition, absolute difference between CYST and LARV increased at parasite intensities >100 indicating that the method has reduced functionality when estimating parasite intensity in heavily infected salmonid populations. However, overall, using this simplified and less time-consuming methodology, a good indication of Diphyllobothrium spp. intensity, abundance and prevalence was obtained. We suggest that this method provides a sound proxy of the Diphyllobothrium spp. burden and have the potential to be used in parasite assessment during fish monitoring and fisheries management surveys, particularly if the time and resources for detailed parasite studies are not available.

Effects of fish species composition on Diphyllobothrium spp. infections in brown trout - is three-spined stickleback a key species?

Subarctic populations of brown trout (Salmo trutta) are often heavily infected with cestodes of the genus Diphyllobothrium, assumedly because of their piscivorous behaviour. This study explores possible associations between availability of fish prey and Diphyllobothrium spp. infections in lacustrine trout populations. Trout in (i) allopatry (group T); (ii) sympatry with Arctic charr (Salvelinus alpinus) (group TC); and (iii) sympatry with charr and three-spined stickleback (Gasterosteus aculeatus) (group TCS) were contrasted. Mean abundance and intensity of Diphyllobothrium spp. were higher in group TCS compared to groups TC and T. Prevalence, however, was similarly higher in groups TCS and TC compared to group T. Zero-altered negative binomial modelling identified the lowest probability of infection in group T and similar probabilities of infection in groups TC and TCS, whereas the highest intensity was predicted in group TCS. The most infected trout were from the group co-occurring with stickleback (TCS), possibly due to a higher availability of fish prey. In conclusion, our study demonstrates elevated Diphyllobothrium spp. infections in lacustrine trout populations where fish prey are available and suggests that highly available and easily caught stickleback prey may play a key role in the transmission of Diphyllobothrium spp. parasite larvae.

Inter and intra-population phenotypic and genotypic structuring in the European whitefish Coregonus lavaretus, a rare freshwater fish in Scotland.

This study revealed between-lake genetic structuring between Coregonus lavaretus collected from the only two native populations of this species in Scotland, U.K. (Lochs Eck and Lomond) evidenced by the existence of private alleles (12 in Lomond and four in Eck) and significant genetic differentiation (FST = 0·056) across 10 microsatellite markers. Juvenile C. lavaretus originating from eggs collected from the two lakes and reared in a common-garden experiment showed clear phenotypic differences in trophic morphology (i.e. head and body shape) between these populations indicating that these characteristics were, at least partly, inherited. Microsatellite analysis of adults collected from different geographic regions within Loch Lomond revealed detectable and statistically significant but relatively weak genetic structuring (FST = 0·001-0·024) and evidence of private alleles related to the basin structure of the lake. Within-lake genetic divergence patterns suggest three possibilities for this observed pattern: (1) differential selection pressures causing divergence into separate gene pools, (2) a collapse of two formerly divergent gene pools and (3) a stable state maintained by balancing selection forces resulting from spatial variation in selection and lake heterogeneity. Small estimates of effective population sizes for the populations in both lakes suggest that the capacity of both populations to adapt to future environmental change may be limited.

[PARASITES FAUNA OF THE LAKE KRONOTSKOE CHARRS (SALVELINUS), KAMCHATKA].

The new data on the parasites fauna of the Lake Kronotskoe sympatric charr forms (genus Salvelinus (Nilsson) Richardson, 1836) is presented. Parasites fauna of Bigmouth and Smallmouth charr forms are described for the first time. The information about Longhead charr, Nosed charr and White charr parasites is added. 29 species of parasites from 9 classes were found: Oligohymenophorea, Myxosporea, Monogenea, Trematoda, Cestoda, Nematoda, Acantocephala, Crustacea and Hirudinea. Longhead charr was the most intensively infected by Proteocephalus longicollis (Zeder, 1800) (abundance 306.0) and Neoechinorhynchus salmonis Ching, 1984 (abundance 230.0). White charr was mostly infected by Crepidostomum Braun, 1900 (abundance 242.2) and P. longicollis (abundance 183.4). Nosed charr group that feed on gammarids was infected mostly by Crepidostomum spp. (abundance 3461.3), Cyathocephalus truncatus (Pallas, 1781) (abundance 179.9) and Cystidicola farionis Fisher, 1798 (abundance 169.0); while Chironomidae consumers group was infected mostly by Diplostomum Nordmann, 1832 (abundance 62.3) and Phyllodistomum umblae (Fabricius, 1780) (abundance 27.3). Bigmouth charr was infected mostly by P. longicollis (abundance 17.0) and Eubolhrium salvelini Schrank, 1790 (abundance 11.0), Smallmouth charr form ­ by P. longicollis (abundance 67.0) and Diplostomum sp. (abundance 64.2). Sympatric flock of charrs form the Lake Kronotskoe (Kamchatka) is the most polymorphic for the genus Salvelinus in Eurasia. According to the parasitological analysis this flock consists six ecological forms.

Transmission dynamics of the monogenean Gyrodactylus salaris under seminatural conditions.

Tracking individual variation in the dynamics of parasite infections in wild populations is often complicated by lack of knowledge of the epidemiological history of hosts. Whereas the dynamics and development of Gyrodactylus salaris Malmberg, 1957, on Atlantic salmon, Salmo salar L., are known from laboratory studies, knowledge about infection development on individual wild fishes is currently sparse. In this study, the dynamics of an infection of G. salaris on individually marked Atlantic salmon parr was followed in a section of a natural stream. During the 6-week experiment, the prevalence increased from 3.3 to 60.0%, with an average increase in intensity of 4.1% day(-1) . Survival analyses showed an initially high probability (93.6%) of staying uninfected by G. salaris, decreasing significantly to 37% after 6 weeks. The results showed that even at subarctic water temperatures and with an initially low risk of infection, the parasite spread rapidly in the Atlantic salmon population, with the capacity to reach 100% prevalence within a short summer season. The study thus track individual infection trajectories of Atlantic salmon living under near-natural conditions, providing an integration of key population parameters from controlled experiments with the dynamics of the epizootic observed in free-living living populations.

Paediatric airway management: basic aspects.

Paediatric airway management is a great challenge, especially for anaesthesiologists working in departments with a low number of paediatric surgical procedures. The paediatric airway is substantially different from the adult airway and obstruction leads to rapid desaturation in infants and small children. This paper aims at providing the non-paediatric anaesthesiologist with a set of safe and simple principles for basic paediatric airway management. In contrast to adults, most children with difficult airways are recognised before induction of anaesthesia but problems may arise in all children. Airway obstruction can be avoided by paying close attention to the positioning of the head of the child and by keeping the mouth of the child open during mask ventilation. The use of oral and nasopharyngeal airways, laryngeal mask airways, and cuffed endotracheal tubes is discussed with special reference to the circumstances in infants. A slightly different technique during laryngoscopy is suggested. The treatment of airway oedema and laryngospasm is described.

Experiments to test if allopatric Salvelinus alpinus are suitable year-round hosts of Gyrodactylus salaris (Monogenea).

There has been an increased focus on Salvelinus alpinus as a potential long-term host to Gyrodactylus salaris and, here, both susceptibility to G. salaris and ability to sustain a parasite population seasonally, was tested using fry and parr of S. alpinus from the River Skibotnelva, northern Norway. Fry were highly susceptible. Gyrodactylus salaris survived on allopatric S. alpinus parr during the 5 month-long winter when water temperatures were c. 1 degrees C. Salvelinus alpinus fry also maintained a pulse of G. salaris infection for over 155 days from early May until autumn. Gyrodactylus salaris are thus able to reproduce and survive on S. alpinus for long periods and at low water temperatures. In spring, newly hatched fry of S. alpinus may serve as an important host to maintain a G. salaris metapopulation within a river system. The results suggest that S. alpinus are adequate long-term hosts of G. salaris independent of the presence of the co-occurring highly susceptible S. salar.

Constrained liners for recurrent dislocations in total hip arthroplasty.

This study reports the results and complications from treating recurrent hip dislocations with a constrained liner (CL) after total hip arthroplasty (THA). Forty patients who had a CL inserted as a secondary prophylactic treatment were retrospectively reviewed after a median observation period of 27 months (range 7-77 months). During the observation period five patients had to be revised: one for deep infection and four on account of re-dislocations. Our results indicate that patients with recurrent THA dislocations can be treated with a CL and has a satisfactory low complication rate and a relatively low risk of re-dislocation.

Parallel evolution of ecomorphological traits in the European whitefish Coregonus lavaretus (L.) species complex during postglacial times.

The extensive phenotypic polymorphism in the European whitefish has triggered evolutionary research in order to disentangle mechanisms underlying diversification. To illuminate the ecological distinctiveness in polymorphic whitefish, and evaluate taxonomic designations, we studied nine Norwegian lakes in three watercourses, which each harboured pairs of divergent whitefish morphs. We compared the morphology and life history of these morphs, documented the extent of genetic differentiation between them, and contrasted the niche use of sympatric morphs along both the habitat and resource axes. In all cases, sympatric morphs differed in the number of gill rakers, a highly heritable trait related to trophic utilization. Individual growth rate, age and size at maturity, diet and habitat use also differed between morphs within lakes, but were remarkably similar across lakes within the same morph. Microsatellite analyses confirmed for all but one pair that sympatric morphs were significantly genetically different, and that similar morphs from different lakes likely have a polyphyletic origin. These results are most compatible with the process of parallel evolution through recurrent postglacial divergence into pelagic and benthic niches in each of these lakes. We propose that sparsely and densely rakered whitefish sympatric pairs may be a likely case of ecological speciation, mediated in oligotrophic lakes with few trophic competitors.

Selective predation on parasitized prey--a comparison between two helminth species with different life-history strategies.

In Lake Fjellfrøsvatn, northern Norway, the larval helminths Cyathocephalus truncatus and Cystidicola farionis use Gammarus lacustris as intermediate hosts and Arctic charr (Salvelinus alpinus) as final hosts. There was sampled 1,433 live G. lacustris from the lake and 1,964 G. lacustris from stomach contents of the charr. Prevalence of infection were, respectively, 0.49% and 3.72% for C. truncatus, and 0.21% and 0.20% for C. farionis. Usually, only 1 parasite was present in each host, and the 2 parasite species never co-occurred. Gammarus lacustris amphipods parasitized by C. truncatus were positively selected by the Arctic charr and were consumed approximately 8 times as often as were the unparasitized amphipods or the amphipods infected with C. farionis. This suggests that G. lacustris amphipods infected with C. truncatus larvae are more susceptible to predation than noninfected specimens, probably because of parasite-induced alterations in behavior or visibility. Alternatively, this could also be explained by selection toward the largest G. lacustris specimens observed, which are also the most frequently parasitized amphipods. However, the data show clearly that this was not a result of size-selective predation by the charr. In contrast, the presence of C. farionis did not increase the susceptibility to predation of its intermediate host. The discrepancy between the 2 helminth species supports the hypothesis that parasite-increased susceptibility to predation is related to the life history strategies of the parasites.

[Evaluation of the new doctoral degree program at the Faculty of Medicine in Oslo 1993-98]. / Evaluering av doktorgradsprogrammet ved Det medisinske fakultet i Oslo 1993-98.

BACKGROUND: In 1993, the doctoral degree programme in the Faculty of Medicine of the University of Oslo was substantially revised to include coursework and supervision of thesis work. PhD students were expected to complete their work towards the doctorate in three years, and funding was only provided for this period. MATERIAL AND METHODS: In spring 1999, all doctoral candidates, their supervisors and members of the adjudicating committees were invited to reply to a questionnaire with the purpose of evaluating the results of the new programme over the 1993-99 period. RESULTS: Only a few doctoral students had been able to obtain their degrees in three years, the defined length of the programme. The mean age for new PhDs was 38; however, physicians obtained their PhD at a later age than the other life scientists enrolled in the programme, and the percentage of PhDs with a medical background declined from 71% in 1993-95 to 51% in 1996-98. INTERPRETATION: The doctoral programme should be extended from three to four years. More physicians should go into research soon after graduating from medical school and more openings for postdocs should be created. More time for research in the university clinics is also needed.

Foot-and-mouth disease: a review of the virus and the symptoms.

Foot-and-mouth disease virus (FMDV) is the etiologic agent of foot-and-mouth disease (FMD), which is a disease of cattle, swine, and other cloven-footed animals. FMD is characterized by the formation of vesicles on the tongue, nose, muzzle, and coronary bands of infected animals. The virus has several unique characteristics that enable it to cause one of the most economically devastating diseases in today's world. The ease with which it may be transmitted by contact and aerosol, combined with its enhanced ability to initiate infections, virtually ensures that most, if not all, animals in a herd will contract FMD. The long-term survival of FMDV in infected animals' tissues and organs, especially when refrigerated, offers an opportunity for its national and international transmission through the food chain. Multiple serotypes and numerous subtypes reduce the effectiveness and reliability of vaccines. The possible development of carriers in vaccinated animals and those that have recovered from FMD provides additional potential sources of new outbreaks. These features create a disease that can have a major economic impact on farmers and entire nations.