Long-term stability of thyroid peroxidase antibody (anti-TPO) in serum in the Danish General Suburban Population Study

OBJECTIVES

We evaluated the long-term stability of thyroid peroxidase antibody (anti-TPO).

METHODS

In the Danish General Suburban Population Study (GESUS), serum samples were biobanked at -80 °C during 2010-2013. In a paired design with 70 subjects, we compared anti-TPO (30-198 U/mL) measured on fresh serum on Kryptor Classic in 2010-2011 (anti-TPOfresh) with anti-TPO remeasured on frozen serum (anti-TPOfrozen) on Kryptor Compact Plus in 2022. Both instruments used the same reagents and the anti-TPOn automated immunofluorescent assay, which was calibrated against the international standard NIBSC 66/387, based on the Time Resolved Amplified Cryptate Emission (TRACE) technology from BRAHMS. Values greater than 60 U/mL are regarded as positive in Denmark with this assay. Statistical comparisons included Bland-Altman, Passing-Bablok regression, and Kappa statistic.

RESULTS

The mean follow-up time was 11.9 years (SD: 0.43). For anti-TPOfrozen vs. anti-TPOfresh, the line of equality was within the confidence interval of the absolute mean difference [5.71 (-0.32; 11.7) U/mL] and the average percentage deviation [+2.22% (-3.89%; +8.34%)]. The average percentage deviation of 2.22% did not exceed analytical variability. Passing-Bablok regression revealed both a statistically significant systematic and proportional difference: Anti-TPOfrozen=-22.6 + 1.22*(anti-TPOfresh). Frozen samples were correctly classified as positive in 64/70 (91.4%; Kappa=71.8%).

CONCLUSIONS

Anti-TPO serum samples in the range 30-198 U/mL were stable after 12-years of storage at -80 °C with an estimated nonsignificant average percentage deviation of +2.22%. This comparison is based on Kryptor Classic and Kryptor Compact Plus, which used identical assays, reagents, and calibrator, but for which the agreement in the range 30-198 U/mL is unclarified.

Interferon alpha-2 treatment reduces circulating neutrophil extracellular trap levels in myeloproliferative neoplasms

Neutrophil extracellular traps (NETs) may play a pathogenic role in the thrombosis associated with myeloproliferative neoplasms (MPNs). We measured serum NET levels in 128 pretreatment samples from patients with MPNs and in 85 samples taken after 12 months of treatment with interferon alpha-2 (PEG-IFNα-2) formulations or hydroxyurea (HU). No differences in NET levels were observed across subdiagnoses or phenotypic driver mutations. In PV, a JAK2V617F⁺ allele burden ≥50% associated with increased NET levels (p = 0.006). Baseline NET levels correlated with neutrophil count (r = 0.29, p = 0.001), neutrophil-to-lymphocyte ratio (r = 0.26, p = 0.004) and JAK2V617F allele burden (r = 0.22, p = 0.03), particularly in patients with PV and with allele burden ≥50% (r = 0.50, p = 0.01, r = 0.56, p = 0.002 and r = 0.45, p = 0.03 respectively). In PV, after 12 months of treatment, NET levels decreased on average by 60% in patients with allele burden ≥50%, compared to only 36% in patients with an allele burden <50%. Overall, treatment with PEG-IFNα-2a or PEG-IFNα-2b reduced NETs levels in 77% and 73% of patients, respectively, versus only 53% of HU-treated patients (average decrease across treatments: 48%). Normalization of blood counts did not per se account for these reductions. In conclusion, baseline NET levels correlated with neutrophil count, NLR and JAK2V617F allele burden, and IFNα was more effective at reducing prothrombotic NET levels than HU.

Clonal haematopoiesis of indeterminate potential and impaired kidney function-A Danish general population study with 11 years follow-up

The myeloproliferative neoplasms are associated with chronic kidney disease but whether clonal haematopoiesis of indeterminate potential (CHIP) is associated with impaired kidney function is unknown. In the Danish General Suburban Population Study (N = 19 958) from 2010 to 2013, 645 individuals were positive for JAK2V617F (N = 613) or CALR (N = 32) mutations. Mutation-positive individuals without haematological malignancy were defined as having CHIP (N = 629). We used multiple and inverse probability weighted (IPW)-adjusted linear regression analysis to estimate adjusted mean (95% confidence interval) differences in estimated glomerular filtration rate (eGFR; ml/min/1.73 m² ) by mutation status, variant allele frequency (VAF%), blood cell counts, and neutrophil-to-lymphocyte ratio (NLR). We performed 11-year longitudinal follow-up of eGFR in all individuals. Compared to CHIP-negative individuals, the mean differences in eGFR were -5.6 (-10.3, -0.8, p = .02) for CALR, -11.9 (-21.4, -2.4, p = 0.01) for CALR type 2, and -10.1 (-18.1, -2.2, p = .01) for CALR with VAF ≥ 1%. The IPW-adjusted linear regression analyses showed similar results. NLR was negatively associated with eGFR. Individuals with CALR type 2 had a worse 11-year longitudinal follow-up on eGFR compared to CHIP-negative individuals (p = .004). In conclusion, individuals with CALR mutations, especially CALR type 2, had impaired kidney function compared to CHIP-negative individuals as measured by a lower eGFR at baseline and during 11-year follow-up.

Caught between competing emotions and tensions - a focus group study exploring experiences of family caregivers of out-of-hospital cardiac arrest survivors

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

Being a family member caring for an out-of-hospital cardiac arrest (OHCA) survivor may impact family caregivers’ lives due to the sudden onset of the illness and possible secondary cognitive, emotional and physical challenges. However, experiences of caring for an OHCA survivor are sparsely described.

Purpose

This purpose of this study was to explore the subjective experiences of family caregivers of OHCA survivors as a means of understanding the potential burden they face.

Methods

Using an explorative qualitative approach, six focus group interviews were conducted with a sample of 25 family caregivers of OHCA survivors and analysed using a phenomenological hermeneutic approach inspired by the philosophy of Ricoeur. OHCA survivors and their family caregivers were attenting at a residential rehabilitation course, where the caregivers were interviewed as part of the course.

Results

Three themes emerged: i) Feeling unexpectedly alone and invisible; the family caregivers felt an emotional burden that could not be shared – leading to caregiving being a lonely and anxious experience. The family caregiver felt alone with the responsibility of the shared life, ii) Fear of loss; the fear of losing a loved one was a constant companion contributing to the burden of caregiving, and iii) Adjusting to a new everyday life; the family caregivers had difficulties adjusting to living their lives on the basis of the survivors’ needs. This often resulted in an existential crisis trying to adapt (Figure 1).

Conclusion

The findings of this study illuminate and emphasise the burden experienced by family caregivers and how they can be caught between competing emotions and tensions. The possible caregiver burden following OHCA should be acknowledged.

Systematic screening is needed to identify those at risk of high caregiver burden. Further, collaboration with family care givers should be an essential part of post-cardiac arrest care, and interventions to reduce the burden should be tested and implemented as part of the clinical care of OHCA survivors and their families.

The use of advanced platelet-rich fibrin after surgical removal of mandibular third molars: a systematic review and meta-analysis

The objective of this systematic review was to test the hypothesis of no difference in recovery following surgical removal of mandibular third molars with the application of advanced platelet-rich fibrin (A-PRF) in the extraction socket compared with alternative biomaterials or natural wound healing. A search of MEDLINE (PubMed), Embase, Cochrane Library, and Scopus was conducted. Human randomized controlled trials published in English up until December 31, 2020 were included. Outcome measures were pain, facial swelling, trismus, soft tissue healing, alveolar osteitis, and quality of life; these were evaluated by descriptive statistics and meta-analysis including 95% confidence intervals (CI). Four studies with a low or moderate risk of bias fulfilled the inclusion criteria. A-PRF resulted in significantly lower pain scores when compared with leucocyte platelet-rich fibrin or natural wound healing after 2 days (-16.8, 95% CI -18.9 to -14.7), 3 days (-12.1, 95% CI -13.4 to -10.7), and 7 days (-1.9, 95% CI -2.9 to -0.9). A-PRF seems to have a negligible effect on facial swelling and trismus and some beneficial effect on soft tissue healing. Alveolar osteitis and quality of life were not assessed. The included studies were characterized by considerable heterogeneity and confounding variables. Thus, the level of evidence appears to be inadequate for clinical recommendations according to the focused question.

The role of home visits by a nurse to improve palliation in patients treated with self-expandable metallic stents due to incurable esophageal cancer

Self-expandable metallic stent (SEMS) is a preferred option to relieve dysphagia and to palliate patients with incurable esophageal or gastro-esophageal junction (GEJ) cancer. Health Related Quality of Life (QoL) represents a clinically relevant outcome measure in research focused on palliation of patients with advanced GI cancer. In this context, home visits by a nurse carry the potential to offer important advantages. Eighty patients with incurable esophageal or GEJ cancer were randomized to either standard follow up or to an intervention containing regular home visits by a nurse. The primary outcome variable QoL was assessed by EORTC QLQ-C30 and OES-18 before insertion of SEMS, and at 2, 7 and 12 weeks thereafter. Secondary outcomes were; need for re-interventions, number of patients receiving palliative oncological therapy and overall survival. Sixty-six males and 13 females, with a median age of 71, were included. Self-reported overall QoL was significantly higher in the intervention group (P = 0.03). The organ specific module OES-18 revealed a significant reduction in dysphagia by the intervention (P = 0.03) as well as fewer eating disabilities (P = 0.04). No differences were observed in secondary outcomes except for overall survival, where the median survival was increased from 114 to 183 days by the active intervention (P = 0.02). Home visits by a nurse seem to play an important palliative role after placement of SEMS in patients with incurable esophageal or GEJ cancer by improving QoL and may carry the potential to increase overall survival.

Smoking, blood cells and myeloproliferative neoplasms: meta-analysis and Mendelian randomization of 2·3 million people

Meta-analyses and Mendelian randomization (MR) may clarify the associations of smoking, blood cells and myeloproliferative neoplasms (MPN). We investigated the association of smoking with blood cells in the Danish General Suburban Population Study (GESUS, n = 11 083), by meta-analyses (including GESUS) of 92 studies (n = 531 741) and MR of smoking variant CHRNA3 (rs1051730[A]) in UK Biobank, and with MPN in a meta-analysis of six studies (n (total/cases):1 425 529/2187), totalling 2 307 745 participants. In the meta-analysis the random-effects standardized mean difference (SMD) in current smokers versus non-smokers was 0·82 (0·75-0·89, P = 2·0 * 10^-108 ) for leukocytes, 0·09 (-0·02 to 0·21, P = 0·12) for erythrocytes, 0·53 (0·42-0·64, P = 8·0 * 10^-22 ) for haematocrit, 0·42 (0·34-0·51, P = 7·1 * 10^-21 ) for haemoglobin, 0·19 (0·08-0·31, P = 1·2 * 10^-3 ) for mean corpuscular haemoglobin (MCH), 0·29 (0·19-0·39, P = 1·6 * 10^-8 ) for mean corpuscular volume (MCV), and 0·04 (-0·04 to 0·13, P = 0·34) for platelets with trends for ever/ex-/current smokers, light/heavy smokers and female/male smokers. Analyses presented high heterogeneity but low publication bias. Per allele in CHRNA3, cigarettes per day in current smokers was associated with increased blood cell counts (leukocytes, neutrophils), MCH, red cell distribution width (RDW) and MCV. The pooled fixed-effects odds ratio for MPN was 1·44 [95% confidence interval (CI): 1·33-1·56; P = 1·8 * 10^-19 ; I²  = 0%] in current smokers, 1·29 (1·15-1·44; P = 8·0 * 10^-6 ; I²  = 0%) in ex-smokers, 1·49 (1·26-1·77; P = 4·4 * 10^-6 ; I²  = 0%) in light smokers and 2·04 (1·74-2·39, P = 2·3 * 10^-18 ; I²  = 51%) in heavy smokers compared with non-smokers. Smoking is observationally and genetically associated with increased leukocyte counts and red blood cell indices (MCH, MCV, RDW) and observationally with risk of MPN in current and ex-smokers versus non/never-smokers.

Smoking is associated with increased risk of myeloproliferative neoplasms: A general population-based cohort study

Background

Former studies on smoking as a risk factor for Philadelphia‐negative myeloproliferative neoplasms (MPNs) have mainly been carried out in women's cohorts and studies with various definitions of MPNs. Herein, we conducted a cohort study with register‐based follow‐up of a general population from Denmark, to validate and substantiate prior observations.

Methods

In the Danish Health Examination Survey cohort, we used the Cox proportional‐hazards model adjusted for age, sex, body mass index, and level of education, to calculate hazard ratios (HRs), to investigate, whether daily smokers or occasional/ex‐smokers had an increased risk of MPNs compared to never‐smokers.

Results

From the time of data collection (September 2007 to October 2008) until 1 January 2015, 70 individuals were diagnosed with MPNs among 75 896 study participants. Similar results were observed in both the age and sex adjusted analysis and the multivariable analysis. The multivariable HR of any MPN diagnosis for daily smokers was 2.5 (95% CI: 1.3‐5.0). For essential thrombocytosis, polycythemia vera, myelofibrosis, and MPN‐unclassified, the HRs were 1.8 (95% CI: 0.5‐5.8), 1.7 (95% CI: 0.5‐5.8), 4.3 (95% CI: 0.9‐19), and 6.2 (95% CI: 1.5‐25), respectively. Among occasional/ex‐smokers the corresponding HRs were 1.9 (95% CI: 1.1‐3.3), 1.5 (95% CI: 0.6‐3.7), 0.8 (95% CI: 0.3‐2.4), 0.9 (95% CI: 0.2‐4.4), and 6.2 (95% CI: 1.8‐21). Participants, who smoked >15 g/day, had an overall HR of 3.4 (95% CI: 1.4‐8.2) for any MPN diagnosis, while participants who smoked ≤15 g/day, had an overall HR of 2.1 (95% CI: 0.9‐4.7).

Conclusion

Smoking was associated with MPN development when comparing smokers and never‐smokers. Further studies investigating smoking in MPNs are warranted to substantiate our findings.

Lactase persistence, milk intake, hip fracture and bone mineral density: a study of 97 811 Danish individuals and a meta-analysis

BACKGROUND

Whether a causal relationship exists between milk intake and reduced risk of fractures is unclear.

OBJECTIVES

We tested the hypothesis that genetically determined milk intake reduces the risk of fractures and increases bone mineral density (BMD).

METHODS

We investigated the association between milk intake, LCT-13910 C/T (rs4988235), which is associated with lactase persistence (TT/TC) in Northern Europeans, and hip fractures in three Danish prospective studies (N = 97 811, age ≥20 years). We added meta-analyses of LCT-13910 and fractures and BMD from five published Northern European population studies.

RESULTS

In the Danish studies, the adjusted hazard ratio (HR) for hip fracture per one glass per week higher milk intake was 1.00 (95% CI: 0.99-1.01). The per T-allele milk intake was 0.58 (0.49-0.68) glasses per week, but HR was 1.01 (0.94-1.09) for hip fracture. In meta-analyses of Danish studies with published Northern European population studies, the random effects odds ratio for any fracture was 0.86 (0.61-1.21; I² = 73%) for TT vs. CC and 0.90 (0.68-1.21; I² = 63%) for TC vs. CC. The standardized mean difference in femoral neck BMD was 0.10 (0.02-0.18; I² = 0%) g cm^-2 for TT vs. CC and 0.06 (-0.04 to 0.17; I² = 17%) g cm^-2 for TC vs. CC. There were no differences in lumbar spine or total hip BMD comparing TT or TC with CC.

CONCLUSION

Genetically lifelong lactase persistence with high milk intake was not associated with hip fracture in Danish population-based cohorts. A meta-analysis combining Danish studies with published Northern European population studies also showed that lactase persistence was not associated with fracture risk. Genetic lactase persistence was associated with a higher femoral neck BMD, but not lumbar spine or total hip BMD.

Effect of substituting soybean meal and canola cake with dried distillers grains with solubles at 2 dietary crude protein levels on feed intake, milk production, and milk quality in dairy cows

Dried distillers grain with solubles (DDGS) is an alternative source of feed protein for dairy cows. Previous studies found that DDGS, based on grains other than corn, can substitute for soybean meal and canola cake as a dietary protein source without reducing milk production or quality. As societal concerns exist, and in many areas strict regulation, regarding nitrogen excretion from dairy cows, the dairy industry has focused on reducing dietary protein level and nitrogen excretion. In the present study, we investigated the use of DDGS as a protein source, at a marginally low dietary crude protein (CP) levels, in a grass-clover and corn silage-based ration. The experiment involved 24 Holstein cows and 2 protein sources (DDGS or soybean-canola mixture) fed at 2 levels of CP (14 or 16%) in a 4 × 4 Latin square design. The aim of this study was to evaluate the effect of both protein source and protein level on feed intake, milk yield, and milk quality. The results indicated that feed intake, milk yield, and protein in milk increased when the protein level in the ration was 16% CP compared with 14%. We found no effect of substituting the soybean-canola mixture with DDGS. Moreover, no sensory problems were observed when comparing fresh milk with stored milk, and milk taste was unaffected by DDGS. Milk from cows fed DDGS had a slightly higher content of linoleic acid and conjugated linoleic acid (CLA 9-11), and lower content of C11 to C17 fatty acids than cows fed diets with the soybean-canola mixture. Cows fed the diets with 16% CP produced milk with higher oleic acids and lower palmitic acid content than cows fed 14% CP diets. To conclude, DDGS can substitute for a soybean-canola mixture without affecting feed intake, milk yield and quality, or sensory quality. Under the conditions of this experiment, feeding 16% CP compared with 14% CP in the ration can increase feed intake and milk production.

Effect of substituting soybean meal and canola cake with grain-based dried distillers grains with solubles as a protein source on feed intake, milk production, and milk quality in dairy cows

The growth of the bioethanol industry is leading to an increase in the production of coproducts such as dried distillers grains with solubles (DDGS). Both corn-based DDGS and grain-based DDGS (gDDGS; defined as originating from grain sources such as barley, wheat, triticale, or a mix, excluding corn) appear to be relevant sources of feed and protein for dairy cows. To date, most of the studies investigating DDGS have been performed with corn-based DDGS. The objectives of this study were to determine the effects of the proportion of gDDGS in the diet on feed intake, milk production, and milk quality. The present experiment involved 48 Holstein cows in a replicated 3 × 3 Latin square design with 3 grass-based dietary treatments consisting of 4, 13.5, and 23% gDDGS on a dry matter (DM) basis (L, M, and H, respectively) as a replacement for a concentrate mix. The concentrate mix consisted of soybean meal, canola cake, and beet pulp. Dry matter intake and energy-corrected milk yield were not affected by the proportion of gDDGS in the diet. Daily milk yield decreased with the H diet compared with the L and M diets. The percentage of fat in milk was higher when cows were fed the H diet compared with the L and M diets, whereas milk fat yield was not affected by dietary treatment. The M diet had a higher percentage of protein in milk compared with the L and H diets. Milk protein yield was similar for the L and M diets; however, it decreased for the H diet. Milk taste was not affected by the proportion of gDDGS in the diet or when milk was stored for 7 d. Linoleic acid and conjugated linoleic acid cis-9,trans-11 in milk increased with increasing proportion of gDDGS. To conclude, gDDGS can replace soybean meal and canola cake as a protein source in the diet of dairy cows. Up to 13.5% of the diet may consist of gDDGS without negatively affecting milk production, milk quality, or milk taste. When gDDGS represents 23% of dietary DM, milk production is reduced by 1.6 kg/d, whereas energy-corrected milk production is numerically reduced by 1 kg.

Effect of dietary nitrate level on enteric methane production, hydrogen emission, rumen fermentation, and nutrient digestibility in dairy cows

Nitrate may lower methane production in ruminants by competing with methanogenesis for available hydrogen in the rumen. This study evaluated the effect of 4 levels of dietary nitrate addition on enteric methane production, hydrogen emission, feed intake, rumen fermentation, nutrient digestibility, microbial protein synthesis, and blood methemoglobin. In a 4×4 Latin square design 4 lactating Danish Holstein dairy cows fitted with rumen, duodenal, and ileal cannulas were assigned to 4 calcium ammonium nitrate addition levels: control, low, medium, and high [0, 5.3, 13.6, and 21.1g of nitrate/kg of dry matter (DM), respectively]. Diets were made isonitrogenous by replacing urea. Cows were fed ad libitum and, after a 6-d period of gradual introduction of nitrate, adapted to the corn-silage-based total mixed ration (forage:concentrate ratio 50:50 on DM basis) for 16d before sampling. Digesta content from duodenum, ileum, and feces, and rumen liquid were collected, after which methane production and hydrogen emissions were measured in respiration chambers. Methane production [L/kg of dry matter intake (DMI)] linearly decreased with increasing nitrate concentrations compared with the control, corresponding to a reduction of 6, 13, and 23% for the low, medium, and high diets, respectively. Methane production was lowered with apparent efficiencies (measured methane reduction relative to potential methane reduction) of 82.3, 71.9, and 79.4% for the low, medium, and high diets, respectively. Addition of nitrate increased hydrogen emissions (L/kg of DMI) quadratically by a factor of 2.5, 3.4, and 3.0 (as L/kg of DMI) for the low, medium, and high diets, respectively, compared with the control. Blood methemoglobin levels and nitrate concentrations in milk and urine increased with increasing nitrate intake, but did not constitute a threat for animal health and human food safety. Microbial crude protein synthesis and efficiency were unaffected. Total volatile fatty acid concentration and molar proportions of acetate, butyrate, and propionate were unaffected, whereas molar proportions of formate increased. Milk yield, milk composition, DMI and digestibility of DM, organic matter, crude protein, and neutral detergent fiber in rumen, small intestine, hindgut, and total tract were unaffected by addition of nitrate. In conclusion, nitrate lowered methane production linearly with minor effects on rumen fermentation and no effects on nutrient digestibility.

Novel aspects of health promoting compounds in meat

Meat is an integral part of the human diet. Besides essential amino acids and nutritive factors of high quality and availability, meat provides often overlooked components of importance for human health. These are amino acids and bioactive compounds that may be very important in i) preventing muscle wasting diseases, such as in sarcopenia, ii) reducing food and caloric intake to prevent metabolic syndrome, iii) blood pressure homeostasis via ACE-inhibitory components from connective tissue, and iv) maintaining functional gut environment through meat-derived nucleotides and nucleosides. In addition, meat could be an important source of phytanic acid, conjugated linoleic acids and antioxidants. Further, it becomes increasingly apparent that design of in vitro meat will be possible, and that this development may lead to improved health benefits from commercially viable and sustainable meat products.

Methane production and digestion of different physical forms of rapeseed as fat supplements in dairy cows

The purpose of this experiment was to study the effect of the physical form of rapeseed fat on methane (CH4) mitigation properties, feed digestion, and rumen fermentation. Four lactating ruminal-, duodenal-, and ileal-cannulated Danish Holstein dairy cows (143 d in milk, milk yield of 34.3 kg) were submitted to a 4×4 Latin square design with 4 rations: 1 control with rapeseed meal (low-fat, CON) and 3 fat-supplemented rations with either rapeseed cake (RSC), whole cracked rapeseed (WCR), or rapeseed oil (RSO). Dietary fat concentrations were 3.5 in CON, 5.5 in RSC, 6.2 in WCR, and 6.5% in RSO. The amount of fat-free rapeseed was kept constant for all rations. The forage consisted of corn silage and grass silage and the forage to concentrate ratio was 50:50 on a dry matter basis. Diurnal samples of duodenal and ileal digesta and feces were compiled. The methane production was measured for 4 d in open-circuit respiration chambers. Additional fat reduced the CH4 production per kilogram of dry matter intake and as a proportion of the gross energy intake by 11 and 14%, respectively. Neither the total tract nor the rumen digestibility of organic matter (OM) or neutral detergent fiber were significantly affected by the treatment. Relating the CH4 production to the total-tract digested OM showed a tendency to decrease CH4 per kilogram of digested OM for fat-supplemented rations versus CON. The acetate to propionate ratio was not affected for RSC and WCR but was increased for RSO compared with CON. The rumen ammonia concentration was not affected by the ration. The milk and energy-corrected milk yields were unaffected by the fat supplementation. In conclusion, rapeseed is an appropriate fat source to reduce the enteric CH4 production without affecting neutral detergent fiber digestion or milk production. The physical form of fat did not influence the CH4-reducing effect of rapeseed fat. However, differences in the volatile fatty acid pattern indicate that different mechanisms may be involved.

Milk fatty acid composition and production performance of Danish Holstein and Danish Jersey cows fed different amounts of linseed and rapeseed

Fat supplements are used in diets for dairy cows to increase energy intake and milk production and the fatty acid composition of the feed affects milk fatty acid composition. A total of 74 Danish Holstein and 41 Danish Jersey cows were divided into 4 groups and the cows within each group were fed a mixed ration supplemented with 0, 3.5, 6.8, or 10.2% of dry matter of a linseed:rapeseed (1:3) mixture during lactation wk 6 to 30. Milk yield, fat, and lactose contents were not affected by treatments for Danish Holsteins, whereas these parameters increased when increased amounts of oilseeds were fed to Danish Jerseys. For both breeds, milk protein content decreased when increased amounts of oilseeds were fed. The milk fatty acid composition showed higher concentrations of saturated fatty acids and lower concentrations of unsaturated fatty acids in milk fat from Danish Jerseys compared with Danish Holsteins. Increased amounts of oilseeds in feed increased milk fat concentration of all C18 fatty acids except C18:2 n-6, whereas the content of C6 to C14, C11 to C17, and in particular, C16, decreased. This effect was more pronounced for Danish Holsteins than for Danish Jerseys. The apparent recovery of C18:2 n-6 and C18:3 n-3 decreased when increased amounts of oilseeds were fed; however, this was most likely due to increased amounts of fatty acid from feed used for other energy demands than milk production. It was concluded that up to 6.8% of oilseed supplementation can be fed without production problems and, in many cases, with positive production responses, including an improved milk fatty acid profile.

Milk quality as affected by feeding regimens in a country with climatic variation

To investigate the influence of climatic conditions and season on milk composition, bulk tank milk was sampled on 5 occasions during a period of 15 mo from 20 Swedish dairy farms. These farms included 5 organic and 5 conventional farms in central Sweden and 7 traditional conventional farms and 3 conventional farms growing maize for silage in southern Sweden. Feed data and milk yield were recorded and milk was analyzed for content of fatty acids, carotenoids, and tocopherol. Differences between milk from the 2 regions and between summer and winter seasons were shown. Milk from central Sweden differed from milk from southern Sweden in that it had a higher content of carotenoids, tocopherol, short-chain fatty acids (C4-C14), C18:0, and C18:3 n-3 and a lower content of C16. Summer milk samples had a lower fat content and contained higher amounts of C18:1 cis-9 and conjugated linoleic acid cis-9,trans-11, and lower amounts of C4 to C16 compared with winter milk. Differences between farm types from central Sweden were lower content of conjugated linoleic acid cis-9,trans-11 and higher content of C18:3 n-3 in organic milk compared with conventional milk. In southern Sweden the use of maize silage caused lower milk content of carotenoids and C18:3 n-3 when compared with traditional feeding. Differences in milk composition could be related to climatic differences because legumes are more dominating in the leys of central Sweden and maize growing is limited to southern Sweden.

MAA-1, a novel acyl-CoA-binding protein involved in endosomal vesicle transport in Caenorhabditis elegans

The budding and fission of vesicles during membrane trafficking requires many proteins, including those that coat the vesicles, adaptor proteins that recruit components of the coat, and small GTPases that initiate vesicle formation. In addition, vesicle formation in vitro is promoted by the hydrolysis of acyl-CoA lipid esters. The mechanisms by which these lipid esters are directed to the appropriate membranes in vivo, and their precise roles in vesicle biogenesis, are not yet understood. Here, we present the first report on membrane associated ACBP domain-containing protein-1 (MAA-1), a novel membrane-associated member of the acyl-CoA-binding protein family. We show that in Caenorhabditis elegans, MAA-1 localizes to intracellular membrane organelles in the secretory and endocytic pathway and that mutations in maa-1 reduce the rate of endosomal recycling. A lack of maa-1 activity causes a change in endosomal morphology. Although in wild type, many endosomal organelles have long tubular protrusions, loss of MAA-1 activity results in loss of the tubular domains, suggesting the maa-1 is required for the generation or maintenance of these domains. Furthermore, we demonstrate that MAA-1 binds fatty acyl-CoA in vitro and that this ligand-binding ability is important for its function in vivo. Our results are consistent with a role for MAA-1 in an acyl-CoA-dependent process during vesicle formation.

Anthocyanidins modulate the activity of human DNA topoisomerases I and II and affect cellular DNA integrity

In the present study, we investigated the effect of anthocyanidins on human topoisomerases I and II and its relevance for DNA integrity within human cells. Anthocyanidins bearing vicinal hydroxy groups at the B-ring (delphinidin, DEL; cyanidin, CY) were found to potently inhibit the catalytic activity of human topoisomerases I and II, without discriminating between the IIalpha and the IIbeta isoforms. However, in contrast to topoisomerase poisons, DEL and CY did not stabilize the covalent DNA-topoisomerase intermediates (cleavable complex) of topoisomerase I or II. Using recombinant topoisomerase I, the presence of CY or DEL (> or = 1 microM) effectively prohibited the stabilization of the cleavable complex by the topoisomerase I poison camptothecin. We furthermore investigated whether the potential protective effect vs topoisomerase I poisons is reflected also on the cellular level, affecting the DNA damaging properties of camptothecin. Indeed, in HT29 cells, low micromolar concentrations of DEL (1-10 microM) significantly diminished the DNA strand breaking effect of camptothecin (100 microM). However, at concentrations > or = 50 microM, all anthocyanidins tested (delphinidin, cyanidin, malvidin, pelargonidin, and paeonidin), including those not interfering with topoisomerases, were found to induce DNA strand breaks in the comet assay. All of these analogues were able to compete with ethidium bromide for the intercalation into calf thymus DNA and to replace the minor groove binder Hoechst 33258. These data indicate substantial affinity to double-stranded DNA, which might contribute at least to the DNA strand breaking effect of anthocyanidins at higher concentrations (> or = 50 microM).

Acyl-CoA-binding protein, Acb1p, is required for normal vacuole function and ceramide synthesis in Saccharomyces cerevisiae

In the present study, we show that depletion of acyl-CoA-binding protein, Acb1p, in yeast affects ceramide levels, protein trafficking, vacuole fusion and structure. Vacuoles in Acb1p-depleted cells are multi-lobed, contain significantly less of the SNAREs (soluble N -ethylmaleimide-sensitive fusion protein attachment protein receptors) Nyv1p, Vam3p and Vti1p, and are unable to fuse in vitro. Mass spectrometric analysis revealed a dramatic reduction in the content of ceramides in whole-cell lipids and in vacuoles isolated from Acb1p-depleted cells. Maturation of yeast aminopeptidase I and carboxypeptidase Y is slightly delayed in Acb1p-depleted cells, whereas the maturation of alkaline phosphatase and Gas1p is unaffected. The fact that Gas1p maturation is unaffected by Acb1p depletion, despite the lowered ceramide content in these cells, indicates that ceramide synthesis in yeast could be compartmentalized. We suggest that the reduced ceramide synthesis in Acb1p-depleted cells leads to severely altered vacuole morphology, perturbed vacuole assembly and strong inhibition of homotypic vacuole fusion.

A human topoisomerase II alpha heterodimer with only one ATP binding site can go through successive catalytic cycles

Eukaryotic DNA topoisomerase II is a dimeric nuclear enzyme essential for DNA metabolism and chromosome dynamics. It changes the topology of DNA by coupling binding and hydrolysis of two ATP molecules to the transport of one DNA duplex through a temporary break introduced in another. During this process the structurally and functionally complex enzyme passes through a cascade of conformational changes, which requires intra- and intersubunit communication. To study the importance of ATP binding and hydrolysis in relation to DNA strand transfer, we have purified and characterized a human topoisomerase II alpha heterodimer with only one ATP binding site. The heterodimer was able to relax supercoiled DNA, although less efficiently than the wild type enzyme. It furthermore possessed a functional N-terminal clamp and was sensitive to ICRF-187. This demonstrates that human topoisomerase II alpha can pass through all the conformations required for DNA strand passage and enzyme resetting with binding and hydrolysis of only one ATP. However, the heterodimer lacked the normal stimulatory effect of DNA on ATP binding and hydrolysis as well as the stimulatory effect of ATP on DNA cleavage. The results can be explained in a model, where efficient catalysis requires an extensive communication between the second ATP and the DNA segment to be cleaved.

Cancer-associated cleavage of cytokeratin 8/18 heterotypic complexes exposes a neoepitope in human adenocarcinomas

The intermediate filament network in simple glandular epithelial cells predominantly consists of heterotypic complexes of cytokeratin 8 (K8) and cytokeratin 18 (K18). In contrast to other cytokeratins, K8 and K18 are persistently expressed during malignant transformation, but changes in cell morphology are accompanied by alterations in the intermediate filament network. To study molecular changes, K8 and K18 were purified from surgically removed colon cancer and normal epithelia tissues. Western blotting and amino acid sequencing revealed the presence of abundant K8 and K18 fragments, truncated at the N terminus, from cancerous, but not normal, epithelial cells. The fragmentation pattern indicates proteolysis mediated by several enzymes, including trypsin-like enzymes. The cancer-associated forms of K8 and K18 are specifically recognized by the human antibody, COU-1, cloned from the B cells of a cancer patient. We demonstrate that COU-1 recognizes a unique conformational epitope presented only by a complex between K8 and K18. The epitope is revealed after proteolytic removal of the head domain of either K8 or K18. A large panel of recombinant K8 and K18 fragments, deleted N- or C-terminally, allowed for the localization of the COU-1 epitope to the N-terminal part of the rod domains. Using surface plasmon resonance, the affinity of COU-1 for this epitope was determined to be 10(9) x m(-1), i.e. more than 2 orders of magnitude higher than for intact heterotypic K8/K18 complexes. The cellular distribution of truncated K8/K18 heterotypic complexes in viable adenocarcinomas cells was probed using COU-1 showing small fibrillar structures distinct from those of intact K8/K18 complexes. Previously we demonstrated the binding and subsequent internalization of recombinant Fab COU-1 to live cancer cells. We have thus characterized a cancer neoepitope recognized by the humoral immune system. The results have biological as well as clinical implications.

Dynamics of human DNA topoisomerases IIalpha and IIbeta in living cells

DNA topoisomerase (topo) II catalyses topological genomic changes essential for many DNA metabolic processes. It is also regarded as a structural component of the nuclear matrix in interphase and the mitotic chromosome scaffold. Mammals have two isoforms (alpha and beta) with similar properties in vitro. Here, we investigated their properties in living and proliferating cells, stably expressing biofluorescent chimera of the human isozymes. Topo IIalpha and IIbeta behaved similarly in interphase but differently in mitosis, where only topo IIalpha was chromosome associated to a major part. During interphase, both isozymes joined in nucleolar reassembly and accumulated in nucleoli, which seemed not to involve catalytic DNA turnover because treatment with teniposide (stabilizing covalent catalytic DNA intermediates of topo II) relocated the bulk of the enzymes from the nucleoli to nucleoplasmic granules. Photobleaching revealed that the entire complement of both isozymes was completely mobile and free to exchange between nuclear subcompartments in interphase. In chromosomes, topo IIalpha was also completely mobile and had a uniform distribution. However, hypotonic cell lysis triggered an axial pattern. These observations suggest that topo II is not an immobile, structural component of the chromosomal scaffold or the interphase karyoskeleton, but rather a dynamic interaction partner of such structures.

Modified cytokeratins expressed on the surface of carcinoma cells undergo endocytosis upon binding of human monoclonal antibody and its recombinant Fab fragment

Previously, we have reported on successful imaging of colon, rectal, and pancreatic carcinomas in patients by using a radiolabeled all-human monoclonal antibody, COU-1, directed against modified cytokeratin. To further develop this antibody for use as an immunoconjugate, COU-1 was cloned by phage display selection and the human Fab fragment was expressed in bacteria. Analysis by confocal laser scanning microscopy demonstrated that COU-1 bound in a uniform punctate pattern to the surface of viable carcinoma cells stained at 4 degrees C, and binding increased significantly when cells were cultured on fibronectin, laminin, or collagen IV. In the case of fibronectin, COU-1 staining was particularly enhanced at intercellular junctions. When carcinoma cells were cultured with COU-1 at 37 degrees C for 6 hr, the antibody was found in large perinuclear vesicles and the punctate surface staining was significantly reduced. Similar results were obtained using intact IgM COU-1 and the recombinant Fab fragment. Immunohistological studies indicated that COU-1, in contrast to murine monoclonal antibodies against normal cytokeratin 8 and 18, could differentiate between malignant and normal colon epithelia, and between colon cancer metastasis in the liver and surrounding normal hepatocytes. Within biopsies of malignant tissue, COU-1 exhibited membrane-associated staining of proliferating cells, while resting cells had a filamentous pattern. Thus, modified cytokeratin at the surface of carcinoma cells may represent a new target for immunoconjugates and may explain the promising results of the phase I/II clinical study.

The day-to-day variation in insulin sensitivity in non-insulin-dependent diabetes mellitus patients assessed by the hyperinsulinemic-euglycemic clamp method

The objective was to study the day-to-day variation in insulin sensitivity in non-insulin-dependent diabetes mellitus (NIDDM) and to analyze within- and between-person variances in the glucose infusion rate during steady state (M value). Ten NIDDM patients attending the outpatient clinic at Aarhus Amtssygehus were studied three times under standardized conditions. Each time, a 120-minute hyperinsulinemic-euglycemic clamp was performed. Similar M values were found on the 3 study days, with difference between M values on the 3 days of (mean +/- SD) 0.3 +/- 1.8 mg glucose/kg lean body mass (LBM)/min. The total coefficient of variation (CV) for M values was 57% after the first clamp, 55% after the second, and 53% after the third. Ninety percent of the total day-to-day variation in M values could be ascribed to between-person variation and 10% to within-person variation. Within-person components of variance included all sources of variation other than between-person variation. The within-person CV for M values was 11.9% +/- 7.2% after two clamp studies and 12.1% +/- 7.3% after three (P < .55). In conclusion, under standardized conditions, a valid estimate of insulin sensitivity assessed by the hyperinsulinemic-euglycemic clamp in NIDDM patients is obtained after a single measurement. Because of large between-person variation, paired data should be used when comparing insulin sensitivity in NIDDM patients.