Underlying causes of cryptogenic stroke and TIA in the nordic atrial fibrillation and stroke (NOR-FIB) study - the importance of comprehensive clinical evaluation.

BACKGROUND: Cryptogenic stroke is a heterogeneous condition, with a wide spectrum of possible underlying causes for which the optimal secondary prevention may differ substantially. Attempting a correct etiological diagnosis to reduce the stroke recurrence should be the fundamental goal of modern stroke management. METHODS: Prospective observational international multicenter study of cryptogenic stroke and cryptogenic transient ischemic attack (TIA) patients clinically monitored for 12 months to assign the underlying etiology. For atrial fibrillation (AF) detection continuous cardiac rhythm monitoring with insertable cardiac monitor (Reveal LINQ, Medtronic) was performed. The 12-month follow-up data for 250 of 259 initially included NOR-FIB patients were available for analysis. RESULTS: After 12 months follow-up probable stroke causes were revealed in 43% patients, while 57% still remained cryptogenic. AF and atrial flutter was most prevalent (29%). In 14% patients other possible causes were revealed (small vessel disease, large-artery atherosclerosis, hypercoagulable states, other cardioembolism). Patients remaining cryptogenic were younger (p < 0.001), had lower CHA2DS2-VASc score (p < 0.001) on admission, and lower NIHSS score (p = 0.031) and mRS (p = 0.016) at discharge. Smoking was more prevalent in patients that were still cryptogenic (p = 0.014), while dyslipidaemia was less prevalent (p = 0.044). Stroke recurrence rate was higher in the cryptogenic group compared to the group where the etiology was revealed, 7.7% vs. 2.8%, (p = 0.091). CONCLUSION: Cryptogenic stroke often indicates the inability to identify the cause in the acute phase and should be considered as a working diagnosis until efforts of diagnostic work up succeed in identifying a specific underlying etiology. Timeframe of 6-12-month follow-up may be considered as optimal. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02937077, EudraCT 2018-002298-23.

Vascular risk factor control and adherence to secondary preventive medication after ischaemic stroke.

BACKGROUND: Studies regarding adequacy of secondary stroke prevention are limited. We report medication adherence, risk factor control and factors influencing vascular risk profile following ischaemic stroke. METHODS: A total of 664 home-dwelling participants in the Norwegian Cognitive Impairment After Stroke study, a multicenter observational study, were evaluated 3 and 18 months poststroke. We assessed medication adherence by self-reporting (4-item Morisky Medication Adherence Scale) and medication persistence (defined as continuation of medication(s) prescribed at discharge), achievement of guideline-defined targets of blood pressure (BP) (<140/90 mmHg), low-density lipoprotein cholesterol (LDL-C) (<2.0 mmol L-1 ) and haemoglobin A1c (HbA1c) (≤53 mmol mol-1 ) and determinants of risk factor control. RESULTS: At discharge, 97% were prescribed antithrombotics, 88% lipid-lowering drugs, 68% antihypertensives and 12% antidiabetic drugs. Persistence of users declined to 99%, 88%, 93% and 95%, respectively, at 18 months. After 3 and 18 months, 80% and 73% reported high adherence. After 3 and 18 months, 40.7% and 47.0% gained BP control, 48.4% and 44.6% achieved LDL-C control, and 69.2% and 69.5% of diabetic patients achieved HbA1c control. Advanced age was associated with increased LDL-C control (OR 1.03, 95% CI 1.01 to 1.06) and reduced BP control (OR 0.98, 0.96 to 0.99). Women had poorer LDL-C control (OR 0.60, 0.37 to 0.98). Polypharmacy was associated with increased LDL-C control (OR 1.29, 1.18 to 1.41) and reduced HbA1c control (OR 0.76, 0.60 to 0.98). CONCLUSION: Risk factor control is suboptimal despite high medication persistence and adherence. Improved understanding of this complex clinical setting is needed for optimization of secondary preventive strategies.

Effect of far infrared therapy on arteriovenous fistula maturation, survival and stenosis in hemodialysis patients, a randomized, controlled clinical trial: the FAITH on fistula trial.

BACKGROUND: An arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis treatment. After creation many of the AVFs will never mature or if functioning will need an intervention within 1 year due to an AVF stenosis. Studies investigating possible therapies that improves the AVF maturation and survival are scarce. Far infrared therapy (FIR) has shown promising results. In minor single centre and industry supported trials FIR has shown improved AVF maturation and survival. There is a need of a randomized multicentre controlled trial to examine the effect of FIR on the AVF maturation and survival and to explore the possible AVF protective mechanism induced by the FIR treatment. METHODS: This investigator initiated, randomized, controlled, open-labeled, multicenter clinical trial will examine the effect of FIR on AVF maturation in patients with a newly created AVF (incident) and AVF patency rate after 1 year of treatment in patients with an existing AVF (prevalent) compared to a control group. The intervention group will receive FIR to the skin above their AVF three times a week for 1 year. The control group will be observed without any treatment. The primary outcome for incident AVFs is the time from surgically creation of the AVF to successful cannulation. The primary outcome for the prevalent AVFs is the difference in number of AVFs without intervention and still functioning in the treatment and control group after 12 months. Furthermore, the acute changes in inflammatory and vasodilating factors during FIR will be explored. Arterial stiffness as a marker of long term AVF patency will also be examined. DISCUSSION: FIR is a promising new treatment modality that may potentially lead to improved AVF maturation and survival. This randomized controlled open-labelled trial will investigate the effect of FIR and its possible mechanisms. TRIAL REGISTRATION: Clinicaltrialsgov NCT04011072 (7th of July 2019).

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.

Multidomain intervention for the prevention of cognitive decline after stroke - a pooled patient-level data analysis.

BACKGROUND AND PURPOSE: The aim of this pooled patient-level data analysis was to test if multidomain interventions, addressing several modifiable vascular risk factors simultaneously, are more effective than usual post-stroke care for the prevention of cognitive decline after stroke. METHODS: This pooled patient-level data analysis included two randomized controlled trials using a multidomain approach to target vascular risk factors in stroke patients and cognition as primary outcome. Changes from baseline to 12 months in the trail making test (TMT)-A, TMT-B and 10-words test were analysed using stepwise backward linear mixed models with study as random factor. Two analyses were based on the intention-to-treat (ITT) principle using different imputation approaches and one was based on complete cases. RESULTS: Data from 322 patients (157 assigned to multidomain intervention and 165 to standard care) were analysed. Differences between randomization groups for TMT-A scores were found in one ITT model (P = 0.014) and approached significance in the second ITT model (P = 0.087) and for complete cases (P = 0.091). No significant intervention effects were found for any of the other cognitive variables. CONCLUSION: We found indications that multidomain interventions compared with standard care can improve the scores in TMT-A at 1 year after stroke but not those for TMT-B or the 10-words test. These results have to be interpreted with caution due to the small number of patients.

18F-Labelling of electron rich iodonium ylides: application to the radiosynthesis of potential 5-HT2A receptor PET ligands.

18F-Labelling of aromatic moieties was limited to electron deficient aromatic systems for many years but recent developments have provided access to the direct labelling of electron rich aromatic systems. Herein we report the synthesis and 18F-labelling of iodonium ylide precursors in the pursuit of 18F-labelled 5-HT2A receptor agonist PET-ligands. Subsequent evaluation in pigs showed high brain uptake of the PET ligands but a blocking dose of ketanserin did not significantly reduce the signal in relevant brain regions - indicating that the ligands do not interact specifically with the 5-HT2A receptor in vivo.

Dealing with cancer: a meta-synthesis of patients' and relatives' experiences of participating in psychosocial interventions.

The aim was to synthesise patients' and relatives' experiences of participating in a psychosocial intervention related to having cancer. The study was a meta-synthesis inspired by Noblit & Hare's 'meta-ethnography' approach. We systematically searched six databases and included 33 studies in the meta-synthesis. Inclusion criteria were qualitative studies with relevance to the synthesis topic. The meta-synthesis conceptualised the way in which participants develop their way of living with cancer, and the role psychosocial interventions play in helping them to live through the illness. Five themes symbolising the participants' core experiences were identified: (1) Emotional relief and a sense of well-being, (2) normalisation of experiences and a sense of control, (3) shared experience and a sense of community, (4) a safe place and (5) transformation and adaptability. The findings indicated that psychosocial interventions were used to try to deal with the changes in the human conditions caused by cancer. Sharing their experiences and forming social relationships helped the participants adapt to cancer. An existential perspective may provide a nuanced understanding of patients' and relatives' experiences of participating in psychosocial interventions.

Regional variations of perceived problems in ambulatory care from the perspective of general practitioners and their patients - an exploratory focus group study in urban and rural regions of northern Germany.

BACKGROUND: Patients from rural and urban regions should have equitable access to health care. In Germany, the physician-patient-ratio and the supply of medical services vary greatly between urban and rural areas. The aim of our study was to explore the regional variations of the perceived health care problems in ambulatory care from the perspective of affected professionals and laypersons i.e. general practitioners and their patients. METHODS: We conducted 27 focus groups with general practitioners (n = 65) and patients (n = 145) from urban areas, environs and rural areas in northern Germany. Discussions were facilitated by two researchers using a semi-structured guideline. The transcripts were content analyzed using deductive and inductive categories. RESULTS: General practitioners and patients reported problems due to demographic change and patient behaviour, through structural inequalities and the ambulatory reimbursement system as well as with specialist care and inpatient care. A high physician density, associated with high competition between general practitioners, a high fluctuation of patients and a low status of general practitioners were the main problems reported in urban areas. In contrast, participants from rural areas reported an insufficient physician density, a lack of young recruits in primary care and a resulting increased workload as problematic. All regions are concerned with subjectively inadequate general practitioners' budgets, insufficiently compensated consultations and problems in the cooperation with specialists and inpatient care institutions. Most problems were mentioned by GPs and patients alike, but some (e.g. high competition rates in urban regions and problems with inpatient care) were only mentioned by GPs. CONCLUSIONS: While many problems arise in urban regions as well as in rural regions, our results support the notion that there is an urgent need for action in rural areas. Possible measures include the support of telemedicine, delegation of medical services and reoccupation of vacant practices. The attractiveness of working in rural areas for general practitioners, specialists and clinicians must be increased by consolidating and expanding rural infrastructure (e.g. child care and cultural life). The above mentioned results also indicate that the ambulatory reimbursement system should be examined regarding the reported inequalities. Measures to further enhance the cooperation between general practitioners, specialists and inpatient care should be taken to solve supra-regionally reported problems. Problems showing regional variations indicate the need for measures to balance these variations between the regions. This is the first German study to analyze subjective views of the stakeholders concerned on regionally variating problems in ambulatory care. Further studies are needed to quantify the extent of the identified problems and differences. A corresponding survey is currently under way.

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.

Evaluation of the feeding value of Dichrostachys cinerea pods for fattening pigs in Cuba.

Dichrostachys cinerea (L.) Wight & Arn. is a tropical leguminous shrub widely regarded as an invasive species in Cuba, after having invaded a significant proportion of its arable land during the past decades. Concurrently, smallholder pig producers are highly constrained by the scarcity of protein feeds. This study aimed to assess the feeding value of D. cinerea pod meal (DCPM) as an alternative protein supplement for pigs in Cuban smallholder production systems. An on-farm feeding trial was carried out with three groups (N = 10) of growing-fattening pigs over 60 days, where DCPM replaced 0, 15, and 30% in DM of a dietary commercial concentrate. Then, in an in vivo digestibility trial with eight growing pigs, apparent digestibilities of DCPM were determined for dry matter (DM), organic matter (OM) and crude protein (CP). Finally, in vitro digestibilities for OM (fecal and ileal) and CP (ileal) were determined. In the feeding trial, pig body weight gains were not affected by increased dietary substitution levels of concentrate for DCPM. Blood parameters, with a few exceptions, did not show significant differences among groups. Values for in vivo OM and CP digestibilities were 40.81 and 50.26%, and substantially higher than in vitro values. In conclusion, our results showed that at least 30% of DM in commercial concentrate could be substituted by DCPM without affecting pig growth performances under Cuban smallholder conditions. The low digestibility of DCPM is, however, not acceptable for intensive pig production systems. In vitro enzyme digestibility methods developed for commercial pig feeds are not suitable for DCPM without further calibration.

Bifunctional alloys for the electroreduction of CO2 and CO.

We use density functional theory to study the reduction of CO2 and CO to hydrocarbons through a formyl pathway on (111) and (211) facets of L12 alloys with an A3B composition. We find that several alloys may reduce the thermodynamic overpotential for CO reduction by more than 0.2 V compared to a copper step, however, these alloys are most often rather unstable in aqueous environment or have low alloy formation energies and may be susceptible to segregation destroying the active sites. Strategies to improve alloy stability against corrosion or segregation would likely be needed in order to realize the full potential of these alloys.

Persistent postsurgical pain after video-assisted thoracic surgery--an observational study.

BACKGROUND: The risk of persistent postsurgical pain (PPP) and subsequent pain-related functional impairment may potentially be reduced by video-assisted thoracic surgery (VATS) compared to thoracotomy. The aim of the study was therefore to assess in detail the incidence and consequences on activities of daily living of PPP after VATS. METHODS: Using a prospective observational design, 47 patients undergoing VATS completed both preoperative, early postoperative and 3 months follow-up. Preoperative pain, pain characteristics, psychological factors, pain-related functional impairment and quantitative sensory testing (QST) including nociceptive thresholds were compared with postoperative data. RESULTS: Only five (11%) patients developed PPP with NRS > 3 originating from the surgical area. However, about 30% of patients still reported some pain-related functional impairment from the surgical area within four well-defined domains of everyday activities. Psychological and sensory thermal tests did not predict persistent postoperative pain, except preoperative pin-prick sensitivity was higher in patients with PPP. Postoperative pain 7 days after surgery was significantly higher in PPP patients. Preoperative pain originating from remote areas did not predict PPP. CONCLUSION: The incidence of PPP, nerve damage (based on QST) and pain-related functional impairment following VATS was lower than reported following thoracotomy. No psychological or other factors predicted PPP. These findings call for further large-scale studies to support VATS to decrease PPP.

Co-infection of Nucleospora cyclopteri (Microsporidia) and Kudoa islandica (Myxozoa) in farmed lumpfish, Cyclopterus lumpus L., in Norway: a case report.

This study describes a co-infection of Kudoa islandica (Myxozoa) and Nucleospora cyclopteri (Microsporida) in farmed lumpfish, Cyclopterus lumpus L., in Norway. Several other parasites (Cryptocotyle sp., protozoan ciliates and Gyrodactylus sp.) were also found in gills. In June 2013, the mortality in a farmed lumpfish population increased to 65%. Lumpfish showed erratic swimming behaviour and loss of weight. At necropsy, nodules in the kidney were the only visible lesions. Histologically, all fish showed severe changes with gill inflammation and necrosis in the spleen, kidney and liver. Haemorrhages and necrosis were observed in some hearts. Intracellular microsporidians associated with the lesions were detected in most organs using histological examination and Calcofluor White. Kudoa spores were diagnosed in the skeletal muscle, but no inflammatory response was associated with the presence of the plasmodia. Comparison of 18S ribosomal DNA sequences showed 100% similarity to Kudoa islandica and Nucleospora cyclopteri. Kudoa islandica and N. cyclopteri have previously been described associated with lesions in wild lumpfish in Iceland. In the present case, N. cyclopteri is believed to be the main cause of systemic pathology. This is the first description of K. islandica and N. cyclopteri causing pathology in farmed lumpfish in Norway.

Effect of light-emitting diode (LED) vs. fluorescent (FL) lighting on laying hens in aviary hen houses: Part 2 - Egg quality, shelf-life and lipid composition.

In this 60-wk study, egg quality, egg shelf-life, egg cholesterol content, total yolk lipids, and yolk fatty acid composition of eggs produced by Dekalb white laying hens in commercial aviary houses with either light-emitting diode (LED) or fluorescent (FL) lighting were compared. All parameters were measured at 27, 40, and 60 wk of age, except for egg shelf-life, which was compared at 50 wk of age. The results showed that, compared to the FL regimen, the LED regimen resulted in higher egg weight, albumen height, and albumen weight at 27 wk of age, thicker shells at 40 wk of age, but lower egg weight at 60 wk of age. Egg quality change was similar between the lighting regimens during the 62-d egg storage study, indicating that LED lighting did not influence egg shelf-life. Eggs from both lighting regimens had similar cholesterol content. However, cholesterol concentration of the yolk (15.9 to 21.0 mg cholesterol/g wet weight yolk) observed in this study was higher than that of United States Department of Agriculture (USDA) database (10.85 mg/g). No significant differences in total lipids or fatty acid composition of the yolks were detected between the two lighting regimens.

Implementation of a standardised method for the production of allogeneic serum eye drops from regular blood donors in a Norwegian University Hospital: Some methodological aspects and clinical considerations.

The use of autologous serum eye drops has been shown to be effective for the treatment of many ocular diseases. For patients were repeated blood sampling is not possible, allogeneic serum eye drops have been shown to be an effective and safe alternative. In our institution, we have managed to produce allogeneic serum eye drops from regular blood donors using a standardised procedure. The effectiveness and safety of this product will be evaluated in a clinical trial.

Tocopherol and annatto tocotrienols distribution in laying-hen body.

The impact of supplementing laying-hen feed with annatto tocotrienols (T3s) and alpha-tocopherol on the distribution of various forms of vitamin E and cholesterol throughout the hen's body was evaluated. A total of 18 organs or tissues (skin, fat pad, liver and gall bladder, heart, oviduct, forming yolk, laid yolk, lungs, spleen, kidney, pancreas, gizzard, digestive tract, brain, thigh, breast, manure, and blood) were collected after 7 wk of feeding on diets enriched with various levels of alpha-tocopherol and annatto extract that contained gamma-T3 and delta-T3. Tissue weights, contents of lipid, alpha-tocopherol, gamma-T3, delta-T3, cholesterol, and fatty acid composition of extracted lipids from the collected organs and tissues were determined. Tissue weight and lipid content did not change significantly with feed supplementation treatments, except that the liver became heavier with increased levels of supplementation. Overall, the main organs that accumulated the supplemented vitamin E were fat pad, liver and gall bladder, oviduct, forming yolks, laid yolks, kidney, brain, thigh, and breast. Much of annatto gamma-T3 and delta-T3 (> 90%) was found in the manure, indicating poor uptake. In some tissues (brain and oviduct,) a significant increase in polyunsaturated fatty acids was seen with increased supplementation. Alpha-tocopherol impacted the transfer of gamma-T3 to forming and laid yolks, but did not impact delta-T3 transfer. No significant differences were found in most of the tissues in cholesterol, except a reduction in heart, based on tissue as-is. Blood samples showed large variations in individual hens with no significant differences in total and HDL cholesterol, or total triacylglycerols. Supplementing feed with annatto T3s and alpha-tocopherol showed that the vitamin E profile and distribution of the laying-hen body can be altered, but to different extents depending on tissue. The result of this research has significance in enhancing meat nutrient content.

[Morbidity differences according to nursing stage and nursing setting in long-term care patients: Results of a claims data based study]. / Morbiditätsunterschiede bei Pflegebedürftigen in Abhängigkeit von Pflegesektor und Pflegestufe: Eine Untersuchung auf der Basis von Abrechnungsdaten der Gesetzlichen Krankenversicherung.

BACKGROUND: We analyzed the differences in morbidity patterns of chronic diseases between long-term care dependent persons in nursing homes compared to those dwelling in the community. We also investigated morbidity differences between long-term care need stages in Germany. MATERIALS AND METHODS: The study included claims data of one nationwide operating statutory health insurance in 2006. Inclusion criteria were age ≥ 65 years, minimum 1 out of 46 diagnoses in at least 3 quarters of the year (n = 8,670). A comparison population was formed with n = 114,962. Prevalences, relative risks, and odds ratios for the risk of nursing home care were calculated. RESULTS: In the bivariate analysis, only three chronic diseases - dementia, urinary incontinence, and chronic heart failure - showed a higher risk for nursing home care. Regression analysis revealed that only dementia showed higher odds related to the stage of nursing needs. CONCLUSION: Among the chronic diseases, only dementia shows a substantially elevated risk for nursing home care. Risk studies on other chronic diseases associated with higher risks of long-term care dependency and specific intervention strategies aiming at delaying or preventing nursing home admission should be developed.

Thymic CCL2 influences induction of T-cell tolerance.

Thymic epithelial cells (TEC) and dendritic cells (DC) play a role in T cell development by controlling the selection of the T cell receptor repertoire. DC have been described to take up antigens in the periphery and migrate into the thymus where they mediate tolerance via deletion of autoreactive T cells, or by induction of natural regulatory T cells. Migration of DC to thymus is driven by chemokine receptors. CCL2, a major ligand for the chemokine receptor CCR2, is an inflammation-associated chemokine that induces the recruitment of immune cells in tissues. CCL2 and CCR2 are implicated in promoting experimental autoimmune encephalomyelitis (EAE), a mouse model for multiple sclerosis. We here show that CCL2 is constitutively expressed by endothelial cells and TEC in the thymus. Transgenic mice overexpressing CCL2 in the thymus showed an increased number of thymic plasmacytoid DC and pronounced impairment of T cell development. Consequently, CCL2 transgenic mice were resistant to EAE. These findings demonstrate that expression of CCL2 in thymus regulates DC homeostasis and controls development of autoreactive T cells, thus preventing development of autoimmune diseases.

Presence of Anisakis simplex (Rudolphi, 1809 det. Krabbe, 1878) and Hysterothylacium aduncum (Rudolphi, 1802) (Nematoda; Anisakidae) in runts of farmed Atlantic salmon, Salmo salar L.

One hundred farmed Atlantic salmon, Salmo salar L., were examined for the presence of nematodes by digestion of tissue in HCl-pepsin solution. All fish were sampled from one cage in a fish farm on the Norwegian south-west coast. Fifty harvest quality salmon, that is, salmon for human consumption (mean 5.4 kg, variation 3.0-7.6 kg), were sampled at the processing line while 50 salmon runts (mean 1.1 kg, variation 0.4-1.8 kg), discarded due to poor performance, were sampled from the discard bin after the grading station. Runts are individual fish with clear signs of poor performance over time and abnormal appearance and are thus not processed for human consumption. No nematodes were found in the musculature or viscera of the 50 harvest quality salmon. In total, 75 nematodes were found in 10 (20%) of the runts; 53 nematodes in the viscera and 22 in the musculature. Nematodes in the musculature were identified as Anisakis simplex (Rudolphi, 1809 det. Krabbe, 1878), while nematodes in the viscera were identified as A. simplex and Hysterothylacium aduncum (Rudolphi, 1802).

Technical note: In vitro total gas and methane production measurements from closed or vented rumen batch culture systems.

This study compared measured gas production (GP) and computed CH4 production values provided by closed or vented bottles connected to gas collection bags. Two forages and 3 concentrates were incubated. Two incubations were conducted, where the 5 feeds were tested in 3 replicates in closed or vented bottles, plus 4 blanks, for a total of 64 bottles. Half of the bottles were not vented, and the others were vented at a fixed pressure (6.8 kPa) and gas was collected into one gas collection bag connected to each bottle. Each bottle (317 mL) was filled with 0.4000 ± 0.0010 g of feed sample and 60 mL of buffered rumen fluid (headspace volume = 257 mL) and incubated at 39.0°C for 24 h. At 24 h, gas samples were collected from the headspace of closed bottles or from headspace and bags of vented bottles and analyzed for CH4 concentration. Volumes of GP at 24 h were corrected for the gas dissolved in the fermentation fluid, according to Henry's law of gas solubility. Methane concentration (mL/100mL of GP) was measured and CH4 production (mL/g of incubated DM) was computed using corrected or uncorrected GP values. Data were analyzed for the effect of venting technique (T), feed (F), interaction between venting technique and feed (T × F), and incubation run as a random factor. Closed bottles provided lower uncorrected GP (-18%) compared with vented bottles, especially for concentrates. Correction for dissolved gas reduced but did not remove differences between techniques, and closed bottles (+25 mL of gas/g of incubated DM) had a greater magnitude of variation than did vented bottles (+1 mL of gas/g of incubated DM). Feeds differed in uncorrected and corrected GP, but the ranking was the same for the 2 techniques. The T × F interaction influenced uncorrected GP values, but this effect disappeared after correction. Closed bottles provided uncorrected CH4 concentrations 23% greater than that of vented bottles. Correction reduced but did not remove this difference. Methane concentration was influenced by feed but not by the T × F interaction. Corrected CH4 production was influenced by feed, but not by venting technique or the T × F interaction. Closed bottles provide good measurements of CH4 production but not of GP. Venting of bottles at low pressure permits a reliable evaluation of total GP and CH4 production.