Effects of feeding whole-cracked rapeseeds, nitrate, and 3-nitrooxypropanol on protein composition, minerals, and vitamin B in milk from Danish Holstein cows

The present study was conducted to assess the individual or combined effects of feeding dietary fat (whole-cracked rapeseed), nitrate, and 3-nitrooxypropanol (3-NOP) on protein profile, mineral composition, B vitamins, and nitrate residues in milk from dairy cows. Forty-eight Danish Holstein cows used in an 8 × 8 incomplete Latin square design were fed 8 factorially arranged diets ((30 or 63 g crude fat/kg DM) × (0 or 10 g nitrate/kg DM) × (0 or 80 mg 3-NOP/kg DM)) over 6 periods of 21 d each. In each period, milk samples were collected from individual cows during the third week by pooling milk obtained from 4 consecutive milkings, and analyzed for protein profile including protein modifications, mineral composition, riboflavin, cobalamin, and presence of nitrate residues. Fat supplementation led to an increase in the phosphorylation degree of αS1-CN by 8.5% due to a decreased relative proportion of αS1-CN 8P and an increased relative proportion of αS1-CN 9P and further to a decrease in the relative proportion of αS2-CN by 2.4%. Additionally, fat supplementation decreased the relative proportions of glycosylated and unglycosylated forms of κ-CN, consequently leading to a 3.6% decrease in total κ-CN. In skim milk, K, Ca, P, and Mg concentrations were altered by individual use of fat, nitrate, and 3-NOP. Feeding nitrate resulted in a 5.4% increase in riboflavin concentration in milk while supplementing 3-NOP increased cobalamin concentration in milk by 21.1%. The nitrate concentration in milk was increased upon feeding nitrate however, this increased concentration was well below the maximum permissible limit of nitrate in milk (<50 mg/L). In conclusion, no major changes were observed in milk protein, and mineral compositions by feeding fat, nitrate, and 3-NOP to dairy cows while the increased riboflavin and cobalamin by nitrate and 3-NOP, respectively, could be of beneficial nutritional value for milk consumers.

Identification of rare genetic variants of the αS-caseins in milk from native Norwegian dairy breeds and comparison of protein composition with milk from high-yielding Norwegian Red cows

Several factors influence the composition of milk. Among these, genetic variation within and between cattle breeds influences milk protein composition, protein heterogeneity, and their posttranslational modifications. Such variations may further influence technological properties, which are of importance for the utilization of milk into dairy products. Furthermore, these potential variations may also facilitate the production of differentiated products (e.g., related to specific breeds or specific genetic variants). The objective of this study was to investigate the genetic variation and relative protein composition of the major proteins in milk from 6 native Norwegian dairy breeds representing heterogeneity in geographical origin, using the modern Norwegian breed, Norwegian Red, as reference. In total, milk samples from 144 individual cows were collected and subjected to liquid chromatography-electrospray ionization/mass spectrometry-based proteomics for identification of genetic and posttranslational modification isoforms of the 4 caseins (α_S1-CN, α_S2-CN, β-CN, κ-CN) and the 2 most abundant whey proteins (α-lactalbumin and β-lactoglobulin). Relative quantification of these proteins and their major isoforms, including phosphorylations of α_S1-CN and glycosylation of κ-CN, were determined based on UV absorbance. The presence and frequency of genetic variants of the breeds were found to be very diverse and it was possible to identify rare variants of the CN, which, to our knowledge, have not been identified in these breeds before. Thus, α_S1-CN variant D was identified in low frequency in 3 of the 6 native Norwegian breeds. In general, α_S1-CN was found to be quite diverse between the native breeds, and the even less frequent A and C variants were furthermore detected in 1 and 5 of the native breeds, respectively. The α_S1-CN variant C was also identified in samples from the Norwegian Red cattle. The variant E of κ-CN was identified in 2 of the native Norwegian breeds. Another interesting finding was the identification of α_S2-CN variant D, which was found in relatively high frequencies in the native breeds. Diversity in more common protein genetic variants were furthermore observed in the protein profiles of the native breeds compared with milk from the high-yielding Norwegian Reds, probably reflecting the more diverse genetic background between the native breeds.

Effect of protein concentrate mixtures and dietary addition of exogenous phytase on major milk minerals and proteins, including casein phosphorylation

Variations in major milk minerals, proteins, and their posttranslational modifications are largely under genetic influence, whereas the effect of nongenetic factors is less studied. Through a controlled feeding experiment (incomplete balanced Latin square design), the effect of concentrate mixtures, based on fava beans, rapeseed meal, or soybean meal as main P and protein sources, on milk composition was examined under typical Danish management conditions. Concentrations of P, Ca, and Mg, together with proteomics for relative quantification of major milk proteins and their isoforms, were analyzed in milk samples from 24 cows sampled in 4 periods. Each cow was fed 1 of the 3 diets in each period with or without addition of exogenous phytase. Cows were blocked by lactation stage into early and mid-lactation (23.3 ± 6.7 and 176 ± 15 d in milk, respectively, at the beginning of the experiment, mean ± standard deviation). Significant effects of feed concentrate mixture were observed for milk protein concentration, milk urea nitrogen, citrate, and the percentage of mixed and preformed fatty acids as well as mineral composition, and their distributions within micellar or serum phases. Furthermore, relative contents of α_S1-casein (CN) 9P form and unglycosylated κ-CN and thereby phosphorylation degree of α_S1-CN (PD) and the glycosylation degree of κ-CN were found to be significantly affected by these diets. To our knowledge, we are the first to document that feed concentrate mixture can affect the relative concentrations of α_S1-CN phosphorylation isoforms in milk, and the results suggested an effect on α_S1-CN 9P and PD, but not on α_S1-CN 8P. Furthermore, although only significant for α_S1-CN 8P, we found a lower relative concentration of α_S1-CN 8P and higher α_S1-CN 9P (and thus higher PD) in milk from cows in mid compared with early lactation. Also, protein concentration and concentration of Mg in skim milk and serum as well as relative concentration of α-lactalbumin were found to be significantly affected by lactation stage. Addition of dietary exogenous phytase only had a minor effect on milk composition or functionality with significant effect detected for α-lactalbumin and micellar Mg concentration.

Genetic analysis on infrared-predicted milk minerals for Danish dairy cattle

A group of milk components that has shown potential to be predicted with milk spectra is milk minerals. Milk minerals are important for human health and cow health. Having an inexpensive and fast way to measure milk mineral concentrations would open doors for research, herd management, and selective breeding. The first aim of this study was to predict milk minerals with infrared milk spectra. Additionally, milk minerals were predicted with infrared-predicted fat, protein, and lactose content. The second aim was to perform a genetic analysis on infrared-predicted milk minerals, to identify QTL, and estimate variance components. For training and validating a multibreed prediction model for individual milk minerals, 264 Danish Jersey cows and 254 Danish Holstein cows were used. Partial least square regression prediction models were built for Ca, Cu, Fe, K, Mg, Mn, Na, P, Se, and Zn based on 80% of the cows, selected randomly. Prediction models were externally validated with 8 herds based on the remaining 20% of the cows. The prediction models were applied on a population of approximately 1,400 Danish Holstein cows with 5,600 infrared spectral records and 1,700 Danish Jersey cows with 7,200 infrared spectral records. Cows from this population had 50k imputed genotypes. Prediction accuracy was good for P and Ca, with external R² ≥ 0.80 and a relative prediction error of 5.4% for P and 6.3% for Ca. Prediction was moderately good for Na with an external R² of 0.63, and a relative error of 18.8%. Prediction accuracies of milk minerals based on infrared-predicted fat, protein, and lactose content were considerably lower than those based on the infrared milk spectra. This shows that the milk infrared spectrum contains valuable information on milk minerals, which is currently not used. Heritability for infrared-predicted Ca, Na, and P varied from low (0.13) to moderate (0.36). Several QTL for infrared-predicted milk minerals were observed that have been associated with gold standard milk minerals previously. In conclusion, this study has shown infrared milk spectra were good at predicting Ca, Na, and P in milk. Infrared-predicted Ca, Na, and P had low to moderate heritability estimates.

The effect of UHT-processed dairy milk on cardio-metabolic risk factors

BACKGROUND/OBJECTIVES

Cardiovascular disease (CVD) remains a major cause of death worldwide. Whereas dairy generally is associated with a neutral or a beneficial CVD effect, the consumption of ultra-high temperature (UHT)-treated milk has been reported to increase levels of low-density lipoprotein cholesterol (LDL-C) in an uncontrolled study. Our aim was to examine whether semi-skimmed UHT dairy milk increases the risk of CVD development compared with pasteurized (PAST) dairy milk in overweight healthy adults.

SUBJECTS/METHODS

Nineteen healthy men and women participated in a randomized, controlled, crossover study. The effect of intake of 1.5 l of UHT dairy milk or PAST milk, similar in nutritional content, was examined as a supplement to the participant's habitual diet for 21 days in each intervention period. Intake of other dairy products was not allowed during the intervention period. Clinical evaluation and blood samples took place preintervention and postintervention.

RESULTS

There was no significant effect by type of milk on LDL-C (P=0.29). No effects of type of milk were observed in other blood lipid levels, such as total cholesterol, high-density lipoprotein cholesterol or triglycerides. No effects of type of milk were found for blood pressure, insulin, glucose concentration and insulin resistance (homeostasis model assessment of insulin resistance) or body weight.

CONCLUSIONS

This study does not support the hypothesis that UHT processing of milk increases the risk of CVD.

An impedance method for spatial sensing of 3D cell constructs--towards applications in tissue engineering

We present the characterisation and validation of multiplexed 4-terminal (4T) impedance measurements as a method for sensing the spatial location of cell aggregates within large three-dimensional (3D) gelatin scaffolds. The measurements were performed using an array of four rectangular chambers, each having eight platinum needle electrodes for parallel analysis. The electrode positions for current injection and voltage measurements were optimised by means of finite element simulations to maximise the sensitivity field distribution and spatial resolution. Eight different 4T combinations were experimentally tested in terms of the spatial sensitivity. The simulated sensitivity fields were validated using objects (phantoms) with different conductivity and size placed in different positions inside the chamber. This provided the detection limit (volume sensitivity) of 16.5%, i.e. the smallest detectable volume with respect to the size of the measurement chamber. Furthermore, the possibility for quick single frequency analysis was demonstrated by finding a common frequency of 250 kHz for all the presented electrode combinations. As final proof of concept, a high density of human hepatoblastoma (HepG2) cells were encapsulated in gelatin to form artificial 3D cell constructs and detected when placed in different positions inside large gelatin scaffolds. Taken together, these results open new perspectives for impedance-based sensing technologies for non-invasive monitoring in tissue engineering applications providing spatial information of constructs within biologically relevant 3D environments.

Effect of heating strategies on whey protein denaturation--Revisited by liquid chromatography quadrupole time-of-flight mass spectrometry

Previous standards in the area of effect of heat treatment processes on milk protein denaturation were based primarily on laboratory-scale analysis and determination of denaturation degrees by, for example, electrophoresis. In this study, whey protein denaturation was revisited by pilot-scale heating strategies and liquid chromatography quadrupole time-of-flight mass spectrometer (LC/MC Q-TOF) analysis. Skim milk was heat treated by the use of 3 heating strategies, namely plate heat exchanger (PHE), tubular heat exchanger (THE), and direct steam injection (DSI), under various heating temperatures (T) and holding times. The effect of heating strategy on the degree of denaturation of β-lactoglobulin and α-lactalbumin was determined using LC/MC Q-TOF of pH 4.5-soluble whey proteins. Furthermore, effect of heating strategy on the rennet-induced coagulation properties was studied by oscillatory rheometry. In addition, rennet-induced coagulation of heat-treated micellar casein concentrate subjected to PHE was studied. For skim milk, the whey protein denaturation increased significantly as T and holding time increased, regardless of heating method. High denaturation degrees were obtained for T >100°C using PHE and THE, whereas DSI resulted in significantly lower denaturation degrees, compared with PHE and THE. Rennet coagulation properties were impaired by increased T and holding time regardless of heating method, although DSI resulted in less impairment compared with PHE and THE. No significant difference was found between THE and PHE for effect on rennet coagulation time, whereas the curd firming rate was significantly larger for THE compared with PHE. Micellar casein concentrate possessed improved rennet coagulation properties compared with skim milk receiving equal heat treatment.

Interdependence of initial cell density, drug concentration and exposure time revealed by real-time impedance spectroscopic cytotoxicity assay

We investigated the combined effect of the initial cell density (12,500, 35,000, 75,000, and 100,000 cells cm(-2)) and concentration of the anti-cancer drug doxorubicin on HeLa cells by performing time-dependent cytotoxicity assays using real-time electrochemical impedance spectroscopy. A correlation between the rate of cell death and the initial cell seeding density was found at 2.5 μM doxorubicin concentration, whereas this was not observed at 5 or 100 μM. By sensing the changes in the cell-substrate interaction using impedance spectroscopy under static conditions, the onset of cytotoxicity was observed 5 h earlier than when using a standard colorimetric end-point assay (MTS) which measures changes in the mitochondrial metabolism. Furthermore, with the MTS assay no cytotoxicity was observed after 15 h of incubation with 2.5 μM doxorubicin, whereas the impedance showed at this time point cell viability that was below 25%. These results indicate that impedance detection reveals cytotoxic events undetectable when using the MTS assay, highlighting the importance of combining impedance detection with traditional drug toxicity assays towards a more in depth understanding of the effect of anti-cancer drugs on in vitro assays. Moreover, the detection of doxorubicin induced toxicity determined with impedance under static conditions proved to be 6 times faster than in perfusion culture.

In vitro digestion of purified β-casein variants A(1), A(2), B, and I: effects on antioxidant and angiotensin-converting enzyme inhibitory capacity

Genetic polymorphisms of bovine milk proteins affect the protein profile of the milk and, hence, certain technological properties, such as casein (CN) number and cheese yield. However, reports show that such polymorphisms may also affect the health-related properties of milk. Therefore, to gain insight into their digestion pattern and bioactive potential, β-CN was purified from bovine milk originating from cows homozygous for the variants A(1), A(2), B, and I by a combination of cold storage, ultracentrifugation, and acid precipitation. The purity of the isolated β-CN was determined by HPLC, variants were verified by mass spectrometry, and molar extinction coefficients at λ=280nm were determined. β-Casein from each of the variants was subjected to in vitro digestion using pepsin and pancreatic enzymes. Antioxidant and angiotensin-converting enzyme (ACE) inhibitory capacities of the hydrolysates were assessed at 3 stages of digestion and related to that of the undigested samples. Neither molar extinction coefficients nor overall digestibility varied significantly between these 4 variants; however, clear differences in digestion pattern were indicated by gel electrophoresis. In particular, after 60min of pepsin followed by 5min of pancreatic enzyme digestion, one ≈4kDa peptide with the N-terminal sequence (106)H-K-E-M-P-F-P-K- was absent from β-CN variant B. This is likely a result of the (122)Ser to (122)Arg substitution in variant B introducing a novel trypsin cleavage site, leading to the changed digestion pattern. All investigated β-CN variants exhibited a significant increase in antioxidant capacity upon digestion, as measured by the Trolox-equivalent antioxidant capacity assay. After 60min of pepsin + 120min of pancreatic enzyme digestion, the accumulated increase in antioxidant capacity was ≈1.7-fold for the 4 β-CN variants. The ACE inhibitory capacity was also significantly increased by digestion, with the B variant reaching the highest inhibitory capacity at the end of digestion (60min of pepsin + 120min of pancreatic enzymes), possibly because of the observed alternative digestion pattern. These results demonstrate that genetic polymorphisms affect the digestion pattern and bioactivity of milk proteins. Moreover, their capacity for radical scavenging and ACE inhibition is affected by digestion.

The occurrence of noncoagulating milk and the association of bovine milk coagulation properties with genetic variants of the caseins in 3 Scandinavian dairy breeds

Substantial variation in milk coagulation properties has been observed among dairy cows. Consequently, raw milk from individual cows and breeds exhibits distinct coagulation capacities that potentially affect the technological properties and milk processing into cheese. This variation is largely influenced by protein composition, which is in turn affected by underlying genetic polymorphisms in the major milk proteins. In this study, we conducted a large screening on 3 major Scandinavian breeds to resolve the variation in milk coagulation traits and the frequency of milk with impaired coagulation properties (noncoagulation). In total, individual coagulation properties were measured on morning milk collected from 1,299 Danish Holstein (DH), Danish Jersey (DJ), and Swedish Red (SR) cows. The 3 breeds demonstrated notable interbreed differences in coagulation properties, with DJ cows exhibiting superior coagulation compared with the other 2 breeds. In addition, milk samples from 2% of DH and 16% of SR cows were classified as noncoagulating. Furthermore, the cows were genotyped for major genetic variants in the αS1- (CSN1S1), β- (CSN2), and κ-casein (CSN3) genes, revealing distinct differences in variant frequencies among breeds. Allele I of CSN2, which had not formerly been screened in such a high number of cows in these Scandinavian breeds, showed a frequency around 7% in DH and DJ, but was not detected in SR. Genetic polymorphisms were significantly associated with curd firming rate and rennet coagulation time. Thus, CSN1S1 C, CSN2 B, and CSN3 B positively affected milk coagulation, whereas CSN2 A(2), in particular, had a negative effect. In addition to the influence of individual casein genes, the effects of CSN1S1-CSN2-CSN3 composite genotypes were also examined, and revealed strong associations in all breeds, which more or less reflected the single gene results. Overall, milk coagulation is under the influence of additive genetic variation. Optimal milk for future cheese production can be ensured by monitoring the frequency of unfavorable variants and thus preventing an increase in the number of cows producing milk with impaired coagulation. Selective breeding for variants associated with superior milk coagulation can potentially increase raw milk quality and cheese yield in all 3 Scandinavian breeds.

Effect of milk hydrolysates on inflammation markers and drug-induced transcriptional alterations in cell-based models

Nonsteroidal anti-inflammatory drugs (NSAID) are associated with gastrointestinal inflammation and subsequent damage to the intestinal tissue. Earlier studies in our laboratory have found that specific casein hydrolysates (CH) might be useful in the treatment of gastrointestinal wounds. The underlying mechanisms that support inflammation and wound healing are not completely understood, but transcriptional alterations may be used as markers for inflammation and wound healing. The bioactivity of 3 CH prepared by treatment of commercial casein with pepsin (60 min) followed by corolase (0, 10, or 60 min) were investigated in intestinal epithelial cells treated with the NSAID indomethacin. The bioactivity was evaluated as transcriptional alterations of transforming growth factor-β1 (TGF-β1), cyclooxygenase-2 (COX-2), peroxisome proliferator-activated receptor-γ (PPAR-γ) and nuclear factor κB (NFκB) by real-time PCR. Furthermore, the effect of CH on lipopolysaccharide-induced inflammation was evaluated in macrophages by measuring PG E(2) levels. Casein hydrolysates treated with corolase for 10 or 60 min after pepsin treatment downregulated transcription of TGF-β1 and NFκB (P < 0.05) compared with the hydrolysate treated with pepsin only. Hydrolysate prepared by corolase treatment for 60 min after pepsin hydrolysis downregulated transcription of COX-2 (P < 0.05) compared with hydrolysate treated with corolase for only 10 min whereas transcription of PPAR-γ was not affected (P > 0.05). Additionally, the hydrolysate prepared by pepsin treatment only (0 min corolase) had a pro-inflammatory effect on macrophages via PG E(2) stimulation (P < 0.05). In conclusion, CH produced by a combination of pepsin and corolase treatments downregulated the transcription levels of TGF-β1, COX-2, and NFκB.

Milk protein genetic variants and isoforms identified in bovine milk representing extremes in coagulation properties

A gel-based proteomic approach consisting of 2-dimensional gel electrophoresis coupled with mass spectrometry was applied for detailed protein characterization of a subset of individual milk samples with extreme rennet coagulation properties. A milk subset with either good or poor coagulation abilities was selected from 892 Danish Holstein-Friesian and Jersey cows. Screening of genetic variants of the major milk proteins resulted in the identification of common genetic variants of β-casein (CN; A(1), A(2), B), κ-CN (A, B), and β-lactoglobulin (LG; A, B), as well as a low frequency variant, κ-CN variant E, and variants not previously reported in Danish breeds (i.e., β-CN variant I and β-LG variant C). Clear differences in the frequencies of the identified genetic variants were evident between breeds and, to some extent, between coagulation groups within breeds, indicating that an underlying genetic variation of the major milk proteins affects the overall milk coagulation ability. In milk with good coagulation ability, a high prevalence of the B variants of all 3 analyzed proteins were identified, whereas poorly coagulating milk was associated with the β-CN variant A(2), κ-CN variant A or E, and β-LG variant A or C. The β-CN variant I was identified in milk with both good and poor coagulation ability, a variant that has not usually been discriminated from β-CN variant A(2) in other studied cow populations. Additionally, a detailed characterization of κ-CN isoforms was conducted. Six κ-CN isoforms varying in phosphorylation and glycosylation levels from each of the genetic variants of κ-CN were separated and identified, along with an unmodified κ-CN form at low abundance. Relative quantification showed that around 95% of total κ-CN was phosphorylated with 1 or 2 phosphates attached, whereas approximately 35% of the identified κ-CN was glycosylated with 1 to 3 tetrasaccharides. Comparing isoforms from individual samples, we found a very consistent κ-CN isoform pattern, with only minor differences in relation to breed, κ-CN genetic variant, and milk coagulation ability.

Composition and effect of blending of noncoagulating, poorly coagulating, and well-coagulating bovine milk from individual Danish Holstein cows

The aim of the present investigation was to study the underlying causes of noncoagulating (NC) milk. Based on an initial screening in a herd of 53 Danish Holstein-Friesians, 20 individual Holstein-Friesian cows were selected for good and poor chymosin-induced coagulation properties; that is, the 10 cows producing milk with the poorest and best coagulating properties, respectively. These 20 selected cows were followed and resampled on several occasions to evaluate possible changes in coagulation properties. In the follow-up study, we found that among the 10 cows with the poorest coagulating properties, 4 cows consistently produced poorly coagulating (PC) or NC milk, corresponding to a frequency of 7%. Noncoagulating milk was defined as milk that failed to form a coagulum, defined as increase in the storage modulus (G') in oscillatory rheometry, within 45min after addition of chymosin. Poorly coagulating milk was characterized by forming a weak coagulum of low G'. Milk proteomic profiling and contents of different casein variants, ionic contents of Ca, P and Mg, κ-casein (CN) genotypes, casein micelle size, and coagulation properties of the 4 NC or PC samples were compared with milk samples of 4 cows producing milk with good coagulation properties. The studies included determination of production of caseinomacropeptide to ascertain whether noncoagulation could be ascribed to the first or second phase of chymosin-induced coagulation. Caseinomacropeptide was formed in all 8 milk samples after addition of chymosin, indicating that the first step (cleavage of κ-CN) was not the cause of inability to coagulate. Furthermore, the effect of mixing noncoagulating and well-coagulating milk was studied. By gradually blending NC with well-coagulating milk, the coagulation properties of the well-coagulating samples were compromised in a manner similar to titration. Milk samples from cows that consistently produced NC milk were further studied at the udder quarter level. The coagulation properties of the quarter milk samples were not significantly different from those of the composite milk sample, showing that poor coagulation traits and noncoagulation traits of the composite milk were not caused by the milk quality of a single quarter. The milk samples exhibiting PC or NC properties were all of the κ-CN variant AA genotype, and contained casein micelles with a larger mean diameter and a lower fraction of κ-CN relative to total CN than milk with good coagulation properties. Interestingly, the relative proportions of different phosphorylation forms of α-CN differed between well-coagulating milk and PC or NC milk samples. The PC and NC milk samples contained a lower proportion of the 2 less-phosphorylated variants of α-CN (α(S1)-CN-8P and α(S2)-CN-11P) compared with samples of milk that coagulated well.

Effect of Protein Composition on the Cheese-Making Properties of Milk from Individual Dairy Cows

The objective of this study was to evaluate the effect of variations in milk protein composition on milk clotting properties and cheese yield. Milk was collected from 134 dairy cows of Swedish Red and White, Swedish Holstein, and Danish Holstein-Friesian breed at 3 sampling occasions. Concentrations of alphaS1-, beta-, and kappa-casein (CN), alpha-lactalbumin, and beta-lactoglobulin (LG) A and B were determined by reversed phase liquid chromatography. Cows of Swedish breeds were genotyped for genetic variants of beta- and kappa-CN. Model cheeses were produced from individual skimmed milk samples and the milk clotting properties were evaluated. More than 30% of the samples were poorly coagulating or noncoagulating, resulting in weak or no coagulum, respectively. Poorly and noncoagulating samples were associated with a low concentration of kappa-CN and a low proportion of kappa-CN in relation to total CN analyzed. Furthermore, the kappa-CN concentration was higher in milk from cows with the AB genotype than the AA genotype of kappa-CN. The concentrations of alphaS1-, beta-, and kappa-CN and of beta-LG B were found to be significant for the cheese yield, expressed as grams of cheese per one hundred grams of milk. The ratio of CN to total protein analyzed and the beta-LG B concentration positively affected cheese yield, expressed as grams of dry cheese solids per one hundred grams of milk protein, whereas beta-LG A had a negative effect. Cheese-making properties could be improved by selecting milk with high concentrations of alphaS1-, beta-, and kappa-CN, with high kappa-CN in relation to total CN and milk that contains beta-LG B.

Drugs in injured drivers in Denmark

As part of the project Impaired Motorists, Methods of Roadside Testing and Assessment for Licensing (IMMORTAL) under the European Commission's Transport RTD Programme of the 5th Framework Programme [I.M. Bernhoft, Drugs in accidents involved drivers in Denmark, D-R4.3 of the project Impaired Motorists, Methods Of Roadside Testing and Assessment for Licensing (IMMORTAL), , 2005], a study regarding drugs in accident-involved drivers was carried out in Denmark. The main objectives of this study were: (1) to collect and analyse samples from injured drivers for the presence of drugs; (2) to give an indication whether drugs may have contributed to traffic accidents; and (3) to get information on the drug-positive drivers and their drug use. This paper focuses on objective 1. Injured drivers who were treated in hospital were asked to give a saliva sample, a blood sample or both. The samples were screened for the following substances: opiates, amphetamines, methamphetamines, incl. MDMA (ecstasy), cannabinoids and metabolites, cocaine and metabolites and benzodiazepines. Screenings were carried out by means of Cozart Microplate EIA kit. Positive screenings were confirmation analysed by gas chromatography-mass spectrometry (GC-MS) or liquid chromatography/tandem mass spectrometry (LC/MS/MS). In total, 26 out of 330 patients were confirmed positive for one or more of the six drug groups. However, three patients were excluded from the survey for various reasons. Of the remaining 23 drug-positive patients 15 were found positive for one drug group, and in five of these cases alcohol was present in a concentration over the legal limit in Denmark (0.05%). The other eight patients were found positive for two drug groups, and in four of these cases, alcohol was also present in a concentration over the legal limit. Alcohol was found both in combinations with medicinal drugs, with illegal drugs and with both. Based on the saliva or blood concentrations, we estimate that there is a strong suspicion of impairment in 9 out of 23 cases, and in another six cases it was likely that the drivers were impaired.

[Injuries sustained by bus passengers in the municipality of Odense 1996-1999]

BACKGROUND

Owing to several recent bus-related accidents in Denmark, we wished to investigate injuries sustained by passengers.

MATERIALS AND METHODS

From our ongoing registration of patients treated in the casualty department at Odense University Hospital, we identified all residents of Odense Municipality who had sustained injuries as bus passengers from 1996 to 1999. Market analysis and demographic information were used to calculate the incidence and risk.

RESULTS

Over this four-year period, 327 consecutive injuries had been sustained by 246 bus passengers, 72 men and 174 women, mean ages 44 and 53 years. The incidence rate was 3.3 injured per 10,000 inhabitants per year, with no increasing tendency during the study period. The risk was 2.2 injured per 1,000,000 bus passengers per year, highest in women and increasing with age. Injuries most frequently occurred when the bus stopped (31%), as passengers were boarding or alighting (23%), or during collision with another vehicle (20%). Most commonly injured areas were the lower (30%) and upper (28%) extremities and the head or neck (27%). Contusions and sprains were the most common injuries (59%). The most common fractures were those of the humerus and hip region.

CONCLUSION

Bus passenger injuries are not a growing problem. The incidence increases with age.

Cytokines and chemokines in respiratory secretion and severity of disease in infants with respiratory syncytial virus (RSV) infection

BACKGROUND

little is known about inflammatory mediators (IM); like cytokines, chemokines and receptors; in respiratory secretion as possible indicators of the severity of respiratory syncytial virus (RSV) disease. Nor have systematic studies been published on the ratios between IM as such indicators.

OBJECTIVE

to define the role of IM ratios as possible indicators of the severity of RSV disease.

STUDY DESIGN

about 46 infants aged 0-9 months with acute RSV infections were studied. Prematurity (PM) and/or underlying disease (UD) were present in 11 of them. The concentrations of seven different IM were measured by ELISA in samples of nasopharyngeal secretions (NPS), four cytokines; IL-1, IL-6, IL-10 and TNF-alpha; the cytokine receptor TNF-R1 and the chemokines; IL-8 and RANTES. 21 IM ratios were calculated from these concentrations. The patients were assigned a clinical score (CS) ranging from 0 to 3 according to the severity of disease.

RESULTS

when 25 patients with severe disease (CS 2-3) and 21 patients with mild disease (CS 0-1) were compared with respect to different IM ratios, three ratios were related to severity of disease: IL-1/RANTES, IL-8/RANTES and TNF-R1/RANTES. When 12 patients with mild disease were compared with 16 patients with severe disease, omitting patients more than 5 months of age and patients with PM and/or UD, the following IM ratios were related to severity of disease: TNF-R1/RANTES, IL-8/RANTES and RANTES/IL-10.

CONCLUSION

of 21 IM ratios studied, TNF-R1/RANTES was related to severity of disease with greatest consistency.

Thermal inactivation kinetics of bovine cathepsin D

Cathepsin D, the principal indigenous acid proteinase in bovine milk, is a lysosomal proteinase, which exists in milk in four forms, including the inactive zymogen procathepsin D. The thermal inactivation kinetics of bovine cathepsin D, isolated from spleen and milk, were studied under isothermal conditions, using a specific HPLC assay to determine residual activity. Inactivation of the blood enzyme preparation followed first order kinetics, with z-values in phosphate buffer (pH 6.7) and skimmed milk of 6.5 and 7.6 degrees C, respectively, the enzyme being far more stable in the latter environment. Inactivation kinetics of the enzyme purified from milk were more complex, and could be best approximated by a double exponential model. Again, stability was higher in milk than in buffer. The double exponential model may indicate differing heat stabilities of isoforms of the enzyme, or stabilization of the enzyme by some milk constituent. It is clear that the enzyme can survive, at least partially, processes such as heating at 55 degrees C for 30 min during manufacture of high-cook cheese varieties (45% survival), and HTST pasteurization (8% survival), and thus may contribute to proteolysis in a range of dairy products.

Antibody responses to Campylobacter infections determined by an enzyme-linked immunosorbent assay: 2-year follow-up study of 210 patients

An enzyme-linked immunosorbent assay (ELISA) was adapted to measure immunoglobulin G (IgG), IgM, and IgA classes of human serum antibody to Campylobacter jejuni and Campylobacter coli. Heat-stable antigen, a combination of C. jejuni serotype O:1,44 and O:53 in the ratio 1:1, was used as a coating antigen in the ELISA test. A total of 631 sera from 210 patients with verified Campylobacter enteritis were examined at various intervals after infection, and a control group of 164 sera were tested to determine the cut-off for negative results. With a 90th percentile of specificity, IgG, IgM, and IgA showed a sensitivity of 71, 60, and 80%, respectively. By combining all three antibody classes, the sensitivity was 92% within 35 days after infection, whereas within 90 days after infection, a combined sensitivity of 90% was found (IgG 68%, IgM 52%, and IgA 76%). At follow-up of the patients, IgG antibodies were elevated 4.5 months after infection but exhibited a large degree of variation in antibody decay profiles. IgA and IgM antibodies were elevated during the acute phase of infection (up to 2 months from onset of infection). The antibody response did not depend on Campylobacter species or C. jejuni serotype, with the important exception of response to C. jejuni O:19, the serotype most frequently associated with Guillain-Barré syndrome. All of the patients infected with this serotype had higher levels of both IgM (P = 0.006) and IgA (P = 0.06) compared with other C. jejuni and C. coli serotypes.

[Spinal cord injury following knife stab wound]

BACKGROUND

Problems about penetrating injuries are well known, but spinal cord damage is rare. Stab wounds to the spinal cord may be a new type of injury in our society.

MATERIAL AND METHODS

We describe two patients brought to our hospital with stab wounds to the cervicothoracic region and major neurologic injury. One was treated initially only with cleaning and primary closure of the skin. After two weeks the intraspinal damage was repaired in our neurosurgical unit. The second patient was immediately brought to neurosurgery. The intraspinal damage was explored and the dural tear was closed.

RESULTS

The first patient got a superficial infection and spinal fluid leakage after initial treatment. This resolved when the dura was closed. There were no wound complications in the second patient. Both demonstrated Brown-Séquard's syndrome. Neurologic recovery was much better in the first than in the second patient.

INTERPRETATION

Minor penetrating wounds in the neck region may represent damage to the spinal cord with major neurologic injury. Further investigation with MR is preferable and we recommend immediate surgical treatment with closure of the dural tear.

Radial nerve palsy after simple fracture of the humerus

Radial nerve palsy is a common complication of simple fracture of the humerus. The aim of this retrospective study was to assess the degree of spontaneous recovery and the need for exploration and repair of the nerve. The study included 26 patients with radial nerve palsy after simple fracture of the humerus. The male:female ratio was 3:1 and the median age was 21 years (range 9-79). Three patients had early exploration of the radial nerve in connection with osteosynthesis, and no appreciable damage to the nerve was found. Two other patients were explored later because they failed to recover. This exploration showed damage to the nerve which required further operation. Twenty-one patients were treated conservatively and all recovered well. None needed later operation. Because of the low incidence of nerve lesions we recommend an expectant policy initially.

Non-occupational ladder and scaffold fall injuries

In the period 1988-1997 a series of 1462 patients aged 15 years or older with non-occupational fall injuries from ladders or scaffolds were studied. We registered 1402 ladder falls and 60 scaffold falls. The mean age was 50 years, and 1052 were males. The mean annual incidence rate was 1.18 per 1000 inhabitants/year for males and 0.41 per 1000 inhabitants/year for females. A rise in the annual incidence rates with increasing age were observed for both males and females, whereas no trend in the annual incidence rates for each of the ten years studied were observed. About 1/5 of the patients were hospitalized with a median number of 7 days. Two patients died following the injury. Half of the registered injuries were contusions or sprains, whereas about 1/3 were fractures or dislocations. The extremities were most commonly injured as 36% of the injuries were located to the lower extremities and 33% to the upper extremities. The forearm was most commonly fractured or dislocated, whereas the ankle joint was most commonly sprained or contused.

[Prolonged neck pain following automobile accidents. Gender and age related risk calculated on basis of data from an emergency department]

Whiplash injuries following road traffic accidents seem to be an increasing problem in many countries. Many studies are based on biased material from specialized departments or data from insurance companies. The aim of this study was to calculate the risk of longer lasting neck pain for persons involved in road traffic accidents and treated in the emergency room. We found that 49% of the patients treated following road traffic accidents in motor vehicles reported problems with neck pain. Thirteen percent had neck pain with more than six months of duration. The highest risk of neck pain was recorded in women aged 20-59 years. Accidents with front to back collisions presented the highest risk. The conclusion was that whiplash associated disorders following road traffic accidents in motor vehicles apparently is a large problem. The treatment and rehabilitation must be centralized at the level of the general practitioners.

The fluctuating pattern of various genome types of respiratory syncytial virus in Copenhagen and some other locations in Denmark

A semi-nested RT-PCR method based on a region of the F and G glycoprotein genes was established, allowing the simultaneous detection and differentiation of group A and group B isolates of respiratory syncytial virus (RSV). The PCR products were subjected to digestion with restriction endonucleases to further differentiate the isolates. Using, in addition, previously reported studies the prevalence of various genome types in the Copenhagen region over a period of 6 years was established. Furthermore, the prevalence of genome types was determined in a distant region in Denmark during the winters of 1996/97 and 1997/98, and in yet another distant region during the winter of 1997/98. It was shown that the different regions in Denmark to a large extent share the same pool of genome types of RSV. Yet, while the fluctuating patterns of the two groups and various genome types were almost identical at different hospitals in the Copenhagen region, they varied between the different regions. This suggests that epidemics in local communities primarily rely on region-specific herd immunity parameters and emerge from strains endemically circulating in these local communities. Group B strains in Copenhagen showed an overall predominance, being predominant in three of the six epidemic seasons studied, and of almost equal predominance in one season.

Severity of respiratory syncytial virus disease related to type and genotype of virus and to cytokine values in nasopharyngeal secretions

BACKGROUND

Investigations concerning the severity of respiratory syncytial virus (RSV) disease as related to (1) RSV type and genotype determined respectively by PCR and restriction enzyme analysis and (2) interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) values in samples of nasopharyngeal secretion (NPS) have not been previously reported.

METHODS

We prospectively studied 105 RSV infections in the lower respiratory tract of infants and young children admitted to a pediatric department in Copenhagen during three winter seasons, 1993, 1994 and 1995. RSV strains were typed and genotyped, respectively, by PCR and nucleic acid restriction analysis and correlated to the severity of the disease. The ratio IL-6:TNF-alpha, determined from IL-6- and TNF-alpha values in samples of NPS, was related to the severity of the disease. Concentrations of IL-6 and of TNF-alpha were determined in serum samples taken during 5 weeks after the onset of illness.

RESULTS

Type B infections produced more severe disease than did type A infections, as assessed on the length of the hospital stay, use of respiratory support and the presence of an infiltrate on a chest radiograph. This difference was age-related. It was observed in infants 0 to 5 months old, but not in older age groups. Type B genotype B1122 produced more severe disease than type A genotype A2311 in infants 0 to 11 months old. Increased serum concentrations of IL-6 and TNF-alpha were detected in samples taken 1 to 2 days after the onset of illness. Whereas TNF-alpha serum concentrations remained high, IL-6 serum concentrations decreased during the following 3 to 4 weeks. The IL-6:TNF-alpha ratio in samples of NPS was related to the severity of the disease. A high ratio was related to a low severity.

CONCLUSIONS

The severity of disease in patients admitted with acute RSV infections can be correlated to the RSV type as determined by PCR, to the RSV genotype as determined by nucleic acid restriction analysis and to the ratio IL-6:TNF-alpha in NPS.

[Malignant melanoma in the small intestine]

A case story of malignant melanoma is presented. The tumour was localised to the jejunum. The symptoms, diagnosis and treatment are described and the pathogenesis is discussed.

Plasminogen activation system in human milk

BACKGROUND

Plasmin is the major endogenous protease present in milk. The level of plasmin activity is controlled by the availability of the precursor plasminogen and by the levels of plasminogen activators and inhibitors. Recently, a differential distribution of tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA) has been demonstrated in bovine milk. To assess whether this distribution pattern is a general feature, the occurrence of components of the plasminogen activation system in different fractions of human milk was investigated.

METHODS

Milk samples were separated into the following fractions; milk fat, skim milk, and milk cells by centrifugation. The different fractions were detected for the presence of plasminogen and plasminogen activators by immunoblotting and zymography. The distribution of t-PA and u-PA was investigated by ligand binding analysis. t-PA-catalyzed plasminogen activation was examined by a coupled chromogenic assay.

RESULTS

A differential distribution of plasminogen, t-PA, and u-PA was found. Casein micelles were found to exhibit t-PA and plasminogen binding activity, whereas the u-PA receptor was identified as the u-PA binding component in the cell fraction. Furthermore, human casein enhanced t-PA-catalyzed plasminogen activation, comparable to the enhancing effect obtained with fibrinogen fragments.

CONCLUSION

The finding of a differential distribution of u-PA and t-PA in milk suggests that the two activators may have different physiological functions, which involve protection against invading microorganisms and maintenance of patency and fluidity in the ducts of mammary gland, respectively.

Primary structure of EPV20, a secretory glycoprotein containing a previously uncharacterized type of domain

A 20-kDa glycoprotein, EPV20, was isolated from bovine milk and characterized. The primary structure was determined by cDNA and protein sequencing combined with mass spectrometry. EPV20 is a 130-residue polypeptide synthesized with a 19-residue signal peptide. The function of EPV20 is unknown, but it displays 79% sequence similarity to a putative protein deduced from a human testis cDNA sequence designated HE1 (human epididymis clone 1) (Kirchhoff, C., 1992. EMBL/GeneBank/DDBJ Databases, accession number X67698). Northern blot analysis showed the bovine EPV20 to be expressed in kidney, spleen, liver and mammary gland, but remarkably not in bovine testis. The six Cys residues of EPV20 were found to be disulfide-linked in a 1-6, 2-3 and 4 5 pattern. This disulfide arrangement has been observed in other proteins, e.g. in human prostatic acid phosphatase, but the spacing between the cystines differs. Therefore, EPV20 represents a new structure among the large group of proteins containing domains with three disulfide bonds.

Bovine milk procathepsin D and cathepsin D: coagulation and milk protein degradation

Cathepsin D is an indigenous aspartic proteinase in bovine milk. By competitive enzyme-linked immunosorbent assay the amount of immunoreactive cathepsin D and procathepsin D in bovine skim milk was estimated to be 0.4 microgram/ml. Immunoreactive cathepsin D purified from whey consisted of a small fraction of mature cathepsin D, but the major form was the proenzyme procathepsin D. A preparation of bovine milk procathepsin D was, like mature cathepsin D, able to degrade purified alpha s1-, alpha s2-, beta- and kappa-casein and alpha-lactalbumin, while beta-lactoglobulin was resistant to cleavage. The cleavage sites in these proteins were determined and compared with those of chymosin. Cathepsin D was capable of generating the alpha s1-I, beta-I, beta-II and beta-III fragments originally described from the action of chymosin on the respective caseins, and these fragments were subjected to further proteolysis. Cathepsin D was also able to liberate the caseinomacropeptide from purified kappa-casein, and to coagulate bovine skim milk. This demonstrated that milk contains an indigenous coagulation enzyme present mainly in the whey fraction.

The age-dependent incidence of injuries due to road traffic accidents in Odense, Denmark from 1980 to 1992

The study was based on data concerning persons treated at Odense University Hospital as a result of road traffic accidents in the period 1980-92. Incidence rates of road traffic accident injuries were calculated on the basis of the population in Odense municipality. The study group included persons older or even 65 years of age, while persons younger than 65 years of age were used as a reference group.

[Frequency of self-reported alcohol influence in injured bicycle riders]

The aim of the study was to determine the frequency of self reported alcohol influence in injured bicyclists. The study was based upon a combination of data from a questionnaire and recordings from the emergency room. Eighteen percent of cyclists 15 years of age or older treated at the emergency room reported themselves influenced by alcohol at the time of accident. The highest injury rate in patients riding under influence was found in the age group 20-29 years, and the proportion of injured cyclists riding under influence was four times higher in males than in females. The lesions sustained by alcohol influenced bicyclists were not more severe than those of the not influenced injured bicyclists.

[Bicycle accidents 1980-1992. Do the official traffic accident statistics show the true picture?]

In Denmark, official statistics concerning road traffic accidents are based upon police recordings. In this study, these official data are compared to data from the emergency room at Odense University Hospital from the period 1980 to 1992. The purpose is to examine whether the official statistics show a reliable picture of the development in accident numbers compared to data from the emergency room. The results confirm that it is necessary to use data from the emergency room to describe the true development in numbers of bicycle accidents.

[Aquatic injuries]

The pattern of injury sustained in an aquascape is described. The most serious and the highest number of injuries were sustained in the water chute (head, face). 15 percent of the injuries were bone or dental fractures. Prophylactic advice is given.

Procathepsin D cannot autoactivate to cathepsin D at acid pH

The amino acid sequence of the propart of bovine procathepsin D was determined at the protein level. Incubation of the isolated procathepsin D at pH 3.5-5.0 for 30-120 min leads to a 2 kDa reduction in its molecular mass, as seen by SDS-PAGE. The activation product is pseudocathepsin D and is the result of a proteolytic cleavage between LeuP26 and IleP27 in the propart. Incubation at pH 5.0 for 20 h of either procathepsin D or pseudocathepsin D results in both cases in approximately equal amounts of pseudocathepsin D and a further processed intermediate, nine amino acids shorter than pseudocathepsin D. No reaction products corresponding to cathepsin D with a mature amino terminus were observed, showing that autoproteolysis alone cannot generate the mature form found in the lysosomes.

Effects of 3-deazaadenosine, an inducer of HL-60 cell differentiation, on human blood cells in vitro

The adenosine analogue 3-deazaadenosine (c3 Ado) induces differentiation of human promyelocytic leukemia HL-60 cells in vitro. c3 Ado affects in vitro viability and growth of cells involved indirectly (cytokine-producing cells) and directly (transformed myeloid cells) in leukemic cell differentiation. Growth inhibition of proliferating cells is achieved at c3 Ado concentrations between 10-100 microM. Concentrations higher than 100 microM affect viability of proliferating and nonproliferating cells.