Cellular model for induction of drip loss in meat

Drip loss from porcine muscle (M. longissimus dorsi) contained high concentrations of K(+) ( approximately 135 mM) and organic osmolytes, for example, taurine ( approximately 15 mM), as well as significant amounts of protein ( approximately 125 mg.mL(-1)). Thus, the drip reflects release of intramuscular components. To simulate events taking place at the time of slaughter and leading to release of osmolytes and subsequent formation of drip loss, C2C12 myotubes were exposed to anoxia and reduction in pH (from 7.4 to 6.0). Anoxia and acidification increased the cellular Ca(2+) concentration ([Ca(2+)](i)) at a rate of 22-32 nM.min(-)(1). The anoxia-induced increase in [Ca(2+)](i) was mainly due to influx via sarcolemmal Na(+) channels. As mammalian cells swell and release lysophospholipids during anoxia, C2C12 cells and primary porcine muscle cells were exposed to either hypotonic shock or lysophosphatidylcholine (LPC) and the release of taurine was followed. The swelling-induced taurine efflux was blocked in the presence of the anion channel blocker (DIDS), the 5-lipooxygenase inhibitors (ETH 615-139 and NDGA) but unaffected by the presence of vitamin E. In contrast, the LPC-induced taurine release was unaffected by DIDS but abolished by antioxidants (butylated hydroxytoluene and vitamin E). Thus, stress-induced taurine release from muscles may precede by two different mechanisms, one being 5-lipooxygenase dependent and the other involving generation of reactive oxygen species. A model for the cellular events, preceding formation of drip in meat, is presented.

Post mortem energy metabolism and pH development in porcine M. longissimus dorsi as affected by two different cooling regimes. A (31)P-NMR spectroscopic study

(31)P-NMR spectroscopy was carried out on M. longissimus dorsi samples chilled by two different cooling profiles corresponding to commercial batch and tunnel chilling. The half-life of post mortem phosphocreatine (PCr) degradation was found to be significantly less in muscle samples exposed to tunnel chilling (rapid) compared with muscle samples exposed to batch chilling (soft) conditions, while no difference in the post mortem ATP degradation was found. Moreover, the post mortem pH development in the muscle samples differed considerably between the two cooling regimes. A maximum difference of approx. 0.25 pH units between the two cooling profiles was observed around 150 min post mortem. Theoretical calculations of the registered pH difference between rapid and soft chilling of muscle samples revealed that the temperature effect on the buffer capacity of muscle is the major determining factor in the detected difference in intracellular pH between the two cooling profiles, while any contribution from a temperature-induced delayed progress in the lactate formation post mortem seems negligible. Moreover, calculations on the effect of the registered pH difference between rapid and soft chilling of muscle samples resemble a 2.5 times greater denaturation of myosin in samples which were chilled softly compared with samples chilled more rapidly. Finally, the relationship to the functionality of meats from soft and rapid chilled pork carcasses is discussed.

Origin of multiexponential T(2) relaxation in muscle myowater

To obtain a further understanding of the nature of the multiexponential T(2) relaxation seen in muscle tissue water (myowater), relaxation measurements were carried out on whole, minced, and homogenized pork of three different qualities with regard to water-holding capacity (normal, red soft exudative, and dark firm dry). Whole, minced, and homogenized pork all resulted in multiexponential T(2) relaxation (three components) independently of the quality, even though microscopic studies on homogenized meat revealed considerable disruption of the macroscopic structure. This states that the relaxation behavior in meat cannot be explained by intra-/extracellular compartmentalization of the water as suggested in earlier studies. Subsequent studies of T(2) relaxation in either whole meat, where the structure integrity was changed by the introduction of dimethyl sulfoxide (membrane disruption) or urea (protein denaturation), or minced meat with added NaCl (inter-/intraprotein interactions) lead to the suggestion that in whole meat (i) the fastest relaxation component reflects water tightly associated with macromolecules, (ii) the intermediate relaxation component reflects water located within highly organized protein structures, for example, water in tertiary and/or quaternary protein structures and spatials with high myofibrillar protein densities including actin and myosin filament structures, and (iii) the slowest relaxation component reflects the extra-myofibrillar water containing the sarcoplasmatic protein fraction. Finally, relaxation patterns in heat-set gels of superprecipitated actomyosin and bovine serum albumin similar to that identified in whole meat support the proposed nature of T(2) relaxation in muscle myowater.

Oxidation of ascorbate in raw milk induced by enzymes and transition metals

The effect of xanthine oxidase, lactoperoxidase, and transition metals [Fe(III), Cu(II)] on the oxidation of ascorbate in raw milk was investigated. Data clearly showed that iron(III) (200 microM) does not accelerate ascorbate oxidation in raw milk in concentrations relevant for raw milk. In contrast, addition of copper(II) (10 microM) to the raw milk accelerated oxidation of ascorbate. Furthermore, both xanthine oxidase and peroxidase activity were found to accelerate ascorbate oxidation dramatically in raw milk, indicating that xanthine oxidase and lactoperoxidase might be some of the most obvious candidates for mediation of ascorbate oxidation in raw milk. The present data are discussed in relation to using the fate of ascorbate in raw milk as an indicator of the oxidative stability of the milk.

Muscle glycogen stores and meat quality as affected by strategic finishing feeding of slaughter pigs

The aim of the present study was to investigate whether muscle glycogen stores in slaughter pigs could be decreased through strategic finishing feeding before slaughter. Moreover, preliminary meat quality traits were measured to see whether such a regulation of muscle glycogen stores affected ultimate pH, color, and tenderness in the meat. The strategic finishing feeding was carried out the last 3 wk prior to slaughter. Seven experimental groups with eight animals per group were fed diets low in digestible carbohydrates. A control group with four animals was fed a traditional grower-finishing diet. The muscle glycogen stores were reduced in longissimus muscle (LM) 11 to 26% at the time of slaughter in pigs that were fed the experimental diets compared with the control group. Meat quality measured as ultimate pH and color on LM muscle in half the pigs 24 h postmortem showed that ultimate pH in LM was not affected by the reduction in glycogen stores in the muscles from pigs fed any of the experimental diets. However, the meat from pigs fed the experimental diets was darker than the meat from pigs that were fed the control diet with two of the experimental diets, resulting in significantly lower L* values. Activities of key enzymes in the glycolytic pathway, glycogen phoshorylase a and b, phosphofructokinase, and the fatty acid oxidative pathway, beta-hydrozyacyl-CoA-dehydrogenase, were not affected by the strategic feeding. In contrast, the activity of the proteolytic enzyme calpain as well as its inhibitor calpastatin was influenced by the strategic feeding. Lower activity of mu-calpain and greater activity of calpastatin in the muscle samples from the strategically fed pigs indicate a lesser muscle protein degradation in the muscles compared with muscles of control animals. The present study showed that the muscle glycogen stores in slaughter pigs can be reduced at the time of slaughter through strategic finishing feeding with diets low in digestible carbohydrate without compromising growth rate.

Antioxidative activity of urate in bovine milk

The antioxidative effects of urate on peroxidase-induced protein oxidation and light-induced riboflavin degradation and lipid oxidation in whole milk were studied. In addition, experiments using ascorbate were conducted to directly compare the antioxidative activity of urate and ascorbate. The presence of urate and/or ascorbate (10-30 mg/L) lowered peroxidase-induced formation of dityrosine by 44-96% in unpasteurized whole milk. No synergistic effect of urate and ascorbate on peroxidase-induced dityrosine formation was registered, but merely an additive effect. Light exposure of pasteurized whole milk showed that ascorbate was oxidized at the expense of urate, which indicated ascorbate-mediated recycling of the urate radical. Moreover, both urate and ascorbate (30 mg/L) retarded light-induced lipid oxidation in pasteurized whole milk as measured by formation of lipid hydroperoxides with urate being the most effective (28% reduction in lipid hydroperoxides) compared with ascorbate (14%). Finally, addition of urate or ascorbate (300 mg/L) to pasteurized whole milk showed a slight protective effect against light-induced degradation of riboflavin with urate being the most effective.

Lactoperoxidase-induced protein oxidation in milk

The reaction between lactoperoxidase (LPO) and H(2)O(2) in the presence of bovine serum albumin (BSA), beta-lactoglobulin, or casein was investigated for the formation of protein radicals by freeze-quench electron spin resonance (ESR) and by the formation of the protein oxidation product, dityrosine. The presence of BSA resulted in a dramatic change after 1 min of reaction in the obtained ESR spectrum compared with the spectrum obtained for LPO and H(2)O(2) alone. Furthermore, experiments employing BSA or beta-lactoglobulin resulted in the formation of long-lived protein radicals detectable 10 min after initiation of the reaction. The presence of casein resulted in a minor change in the fine structure of the ESR spectrum after 1 min of reaction compared with LPO and H(2)O(2) alone, but no difference between the two reaction mixtures could be observed after 10 min of reaction. The formation of dityrosine could be detected in reaction mixtures containing LPO and H(2)O(2) after 1 and 10 min of incubation at 25 degrees C both in the absence and in the presence of BSA, beta-lactoglobulin, or casein. The presence of casein resulted in an increased dityrosine concentration compared with the reaction with LPO and H(2)O(2) alone. Endogenous LPO in unpasteurized milk was activated at 25 degrees C by adding 1 mM H(2)O(2). Radical species could be detected directly in the milk by freeze-quench ESR during the initial phase of the reaction, and dityrosine could be measured after 4 h of incubation. The role of LPO activity in the formation of ESR detectable radical species and dityrosine in milk was further verified in ultrahigh temperature (UHT) milk with no endogenous enzyme activity, as the formation of ESR detectable radical species and dityrosine took place in UHT milk only upon the addition of both H(2)O(2) and exogenous LPO.

Ascorbic acid and ascorbic acid 6-palmitate induced oxidation in egg yolk dispersions

The oxidation in aqueous dispersions of egg yolk powder and the influence of addition of the proposed antioxidants ascorbic acid and ascorbic acid 6-palmitate indicate that both ascorbic acid and ascorbic acid 6-palmitate propagated the oxidation of egg yolk powder dispersions. Ascorbic acid 6-palmitate was found to be more prooxidative than ascorbic acid. Moreover, it was found that addition of ascorbic acid or ascorbic acid 6-palmitate gave rise to an increase in the amount of free iron Fe(II) in the egg yolk dispersions. It is proposed that ascorbic acid and ascorbic acid 6-palmitate react with the phosvitin-Fe(III) complex found in egg yolk and release Fe(II), which subsequently propagates lipid oxidation. It appears that less oxidation occurs in egg yolk dispersions exposed to high concentrations of peroxy radicals with added ascorbic acid than egg yolk dispersions with added ascorbic acid without exposure to peroxy radicals.

Classifying the illumination condition from two light sources by color histogram assessment

We investigate and propose a method for assessment of the illumination condition covering two light sources. The method may be of some support for color vision and multispectral analysis methods that rely on a specific illumination condition. It is constrained to classifying the illumination condition for dielectric objects illuminated by two light sources. The reflected light is modeled by the dichromatic reflection model, which describes the light as the sum of its body reflections and surface reflections. Further, reflected light from an object illuminated by two light sources may give from one to four primary reflections depending on the condition, and it may be expressed as an additive mixture of these reflections. An additive mixture of two reflections expressed in chromaticities is limited to falling within the area enclosed by the chromaticities of the primary reflections of the light sources. So after finding the set of primary chromaticities enclosing the pixel points' chromaticities, it is possible for one to assess the current illumination condition. Since the method operates on pixel points globally, it is independent of illumination geometry and hence may be used on irregular objects. Two experiments are performed. One uses regular objects in a well-controlled laboratory environment and demonstrates that the pixel-point distribution is as expected. The second experiment demonstrates the method's potential use in support of spectroscopic analysis of vegetation through assessing the illumination condition of barley plants in an outdoor illumination condition.

Peroxidation of linoleate at physiological pH: hemichrome formation by substrate binding protects against metmyoglobin activation by hydrogen peroxide

Peroxidation by metmyoglobin, MbFe(III), by metmyoglobin/hydrogen peroxide, MbFe(III)/H(2)O(2), to yield the myoglobin ferryl radical (*MbFe(IV)=O), or by ferrylmyoglobin, MbFe(IV)=O, was investigated at physiological pH (7.4) in oil-in-water linoleate emulsions. Linoleate peroxidation was followed using second derivative ultraviolet (UV)-spectroscopy for monitoring formation of conjugated dienes and quantitative determination of specific linoleate hydroperoxides by liquid chromatography with photodiode absorption detection. Modifications of myoglobins during lipid peroxidation were followed simultaneously by changes in the Soret absorption band (410 or 424 nm), and in the visible absorption region (from 450 to 700 nm), combined with electron spin resonance (ESR) spectroscopy for direct detection of changes in the spin state of the iron center. In contrast to MbFe(IV)=O, MbFe(III) and MbFe(III)/H(2)O(2) were not able to initiate linoleate peroxidation in oil-in-water emulsions, and MbFe(III) was converted, by binding of linoleate (but not methyl linoleate), to a low-spin hemichrome derivate, HMbFe(III), with the distal histidine reversibly bound to the iron center. HMbFe(III) is ineffective in initiating lipid peroxidation and cannot be activated to *MbFe(IV)=O or MbFe(IV)=O by addition of moderate amounts of H(2)O(2). Addition of MbFe(III) to linoleate emulsions containing H(2)O(2) results in the competitive formation of *MbFe(IV)=O and HMbFe(III) in favor of HMbFe(III), and little linoleate peroxidation is detected, demonstrating the inherent protection, at physiologic pH, against peroxidation by reversible binding of the substrate to the potential myoglobin catalyst.

Formation of long-lived radicals on proteins by radical transfer from heme enzymes--a common process?

Incubation of Fe(III)myoglobin (Fe(III)Mb) with H2O2 in the presence of bovine serum albumin (BSA) has been shown previously to give albumin-derived radicals as a result of radical transfer from myoglobin to BSA. In this study the occurrence of similar processes with peroxidases has been investigated using horseradish peroxidase (HRP)/H2O2, in the presence and absence of added tyrosine. Incubation of HRP with H2O2 and bovine or human serum albumins, in the presence and absence of tyrosine, gave long-lived albumin-derived radicals as detected by EPR spectroscopy. Evidence has been obtained for these albumin radicals being located on buried tyrosine residues on the basis of blocking experiments. The effect of protein conformation on radical transfer has been investigated using partial proteolytic digestion prior to protein oxidation. With HRP/H2O2/BSA and Fe(III)Mb/H2O2/BSA increased radical concentrations were observed after limited digestion, although this effect was less marked with the HRP/H2O2/BSA system than with Fe(III)Mb/H2O2/BSA, consistent with different modes of radical transfer. More extensive digestion of BSA decreased the radical concentration to levels below those detected with native albumin, indicating that the tertiary structure of the target protein plays an important role in determining the rate of radical transfer and/or the stability of the resultant species. These results are consistent with a mechanism for the HRP/H2O2/no free tyrosine system involving radical transfer to the albumin via the heme edge of the peroxidase. In contrast, albumin radical formation by the HRP/H2O2/free tyrosine system was only marginally affected by proteolysis, consistent with free tyrosine phenoxyl radicals being the mediators of radical transfer, without significant protein-protein interaction. These protein-to-protein radical transfer reactions may have important consequences for understanding protein oxidation in biological systems.

Formation of amino acid (L-leucine, L-phenylalanine) derived volatile flavour compounds by Moraxella phenylpyruvica and Staphylococcus xylosus in cured meat model systems

A bacterial strain isolated from Danish immersion curing brine, Moraxella phenylpyruvica 0100, and a commercial meat starter culture, Staphylococcus xylosus DD34, were tested for their ability to form characteristic volatile compounds in minimal medium with the added amino acid L-leucine or L-phenylalanine under different environmental conditions (pH 5.5 and 6.0; 0 and 210 ppm nitrate; pre-incubation with and without agitation) and compared with respect to their ability to form volatile compounds in cured meat extracts and vacuum-packed cured meat cuts. The characteristic cured meat aroma precursors/compounds 3-methylbutanal and 3-methylbutanol were found to be formed in cured meat extracts and vacuum-packed cured meat cuts inoculated with M. phenylpyruvica. These volatiles are most probably formed by metabolic conversion of the amino acid L-leucine by M. phenylpyruvica, as they were also produced in minimal media with added L-leucine inoculated with this organism. The characteristic L-phenylalanine derived compound, benzaldehyde, formed by M. phenylpyruvica in minimal medium in the presence of nitrate (210 ppm), was not produced in any noticeable amount in cured meat extracts or vacuum-packed cured meat inoculated with M. phenylpyruvica. In contrast, benzacetaldehyde, which has been described as a possible metabolic product of the microbial conversion of L-phenylalanine, was found to be a characteristic volatile compound formed in cured meat extracts and vacuum-packed cured meat inoculated with M. phenylpyruvica, indicating an alternative metabolic pathway for L-phenylalanine by this organism in a cured meat environment. Even though S. xylosus was able to form volatile compounds characteristic of cured meats (3-methylbutanal, 3-methylbutanol) in minimal media with added L-leucine, this bacterial strain seemed not to be able to produce these characteristic volatiles in the studied cured meat systems. The present data imply that M. phenylpyruvica, in particular, is a potential meat starter for ensuring superior flavour development in cured meat.

Kinetics of reduction of hypervalent iron in myoglobin by crocin in aqueous solution

Crocin in aqueous solution is oxidized by ferrylmyoglobin, MbFe(IV) = O, in a second order reaction with k = 183 l.mol-1.s-1, delta H++298 = 55.0 kJ.mol-1, and delta S++298 = -17 J.mol-1.K-1 (pH = 6.8, ionic strength 0.16 (NaCl), 25 degrees C), as studied by stopped-flow spectroscopy. The reaction has 1:1 stoichiometry to yield metmyoglobin, MbFe(III), and has delta G theta = -11 kJ.mol-1, as calculated from the literature value E0 = +0.85 V (pH = 7.4) vs. NHE for MbFe(IV)=O/MbFe(III) and from the half-peak potential +0.74 V (vs. NHE in aqueous 0.16 NaCl, pH = 7.4) determined by cyclic voltammetry for the one-electron oxidation product of crocin, for which a cation radical structure is proposed and which has a half-peak potential of +0.89 V for its formation from the two-electron oxidation product of crocin. The ferrylmyoglobin protein-radical, MbFe(IV)=O, reacts with crocin with 2:1 stoichiometry to yield MbFe(IV)=O, as determined by ESR spectroscopy, in a reaction faster than the second order protein-radical generating reaction between H2O2 and MbFe(III), for which latter reaction k = 137 l.mol-1.s-1, delta H++298 = 51.5 kJ.mol-1, and delta S++298 = -31 J.mol-1.K-1 (pH = 6.8, ionic strength = 0.16 (NaCl), 25 degrees C) was determined. Based on the difference between the stoichiometry for the reaction between crocin and each of the two hypervalent forms of myoglobin, it is concluded in agreement with the determined half peak reduction potentials, that the crocin cation radical is less reducing compared to crocin, as the cation radical can reduce the protein radical but not the iron(IV) centre in hypervalent myoglobin.

Formation of long-lived protein radicals in the reaction between H2O2-activated metmyoglobin and other proteins

Free radicals formed during the reaction of H2O2 and metmyoglobin in the presence of bovine serum albumin (BSA) were investigated using freeze quench and spin-trap ESR spectroscopy. Increasing concentrations of BSA (0-300 microM) resulted in drastic changes in the characteristic freeze quench ESR signal of H2O2-activated metmyoglobin (perferryl protein radical) under physiological conditions (pH = 7.4; I = 0.16). The radical species formed during reaction of 100 microM H2O2, 100 microM metmyoglobin, and 200 microM BSA have half-lives of approximately 13 min at 25 degrees C, in contrast to the perferryl protein radical that has a half-life of approximately 28 s at 25 degrees C. The radical species formed in the presence of BSA were reactive towards ascorbate, glutathione, cysteine, and tyrosine. Substitution of BSA with defatted BSA, gamma-globulin or beta-lactoglobulin also resulted in formation of long-lived free radical species (half-lives: 13-18 min); however, the ability to form these was dependent of the specific protein and decreased in the following order: BSA > defatted BSA > gamma-globulin > beta-lactoglobulin. The spin-trap alpha-phenyl-tert-butylnitrone (PBN) showed the presence of transient protein radical species formed in the reaction between MMb, H2O2, and BSA. Transient radical species that could be proposed as intermediates in the formation of the long-lived protein radicals detected by freeze-quench ESR. Dityrosine was formed in the reaction between MMb, H2O2, and BSA, showing the involvement of tyrosine residues in the present reaction. The described chemical interaction between H2O2-activated myoglobin and other proteins have major consequences on future interpretations of the significance of the perferryl protein radical in biological systems where proteins are abundant.

Hemichrome formation, lipid peroxidation, enzyme inactivation and protein degradation as indexes of oxidative damage in homogenates of chicken kidney and liver

The change in relative hemichrome formation (RHF) was investigated as a potential marker of oxidative damage in kidney and liver homogenates prepared from chicks fed diets deficient or adequate in vitamin E. RHF gave an earlier indication of oxidative damage in tissue homogenates than the formation of thiobarbituric acid reactive substances (TBARS) or decrease in glutathione peroxidase activity (GPXA). RHF correlated significantly with both TBARS and GPXA. The correlations were 0.64 (P < 0.0001) and -0.57 (P = 0.0002) in kidney homogenates and 0.53 (P = 0.0006) and -0.71 (P < 0.0001) in liver homogenates. The correlation between RHF and the sum of TBARS and GPXA was also highly significant in both kidney and liver homogenates.

Ferrous-iron-induced oxidation in chicken liver slices as measured by hemichrome formation and thiobarbituric acid-reactive substances: effects of dietary vitamin E and beta-carotene

Hemichrome formation in chicken liver slices was determined by employing a Heme Protein Spectra Analysis Program (HPSAP) on the visible spectrum of the liver tissue. Relative hemichrome formation (RHF) in liver tissue exposed to ferrous iron for 1 h at 37 degrees C could be predicted according to the general catalytic equation RHF = k.[Fe2+]/(Ap + [Fe2+]), with k = 132 +/- 30, where the factor Ap represents the additive antioxidative potential in the liver tissue. RHF in Fe2+ exposed liver slices incubated at 37 degrees C for 1 h correlated significantly with formation of thiobarbituric acid-reactive substances (TBARS) (r = .77, P < .0001). RHF was found to decrease significantly with increasing vitamin E concentration in liver tissue exposed to ferrous iron (1 h, 37 degrees C). However, the influence of beta-carotene on RHF in ferrous-iron exposed liver slices (1 h, 37 degrees C) was less evident, as the concentration of Fe2+ was found to be decisive for whether beta-carotene acted as an antioxidant or a prooxidant under the conditions in question. Results in the liver slice model system regarding the effect of vitamin E and beta-carotene on iron overload were supported in a subsequent in vivo iron injection experiment with chicks. These observations indicate that RHF is a sensitive marker for ferrous-iron-induced oxidative damage in the present tissue slice system.

Protection by vitamin E, selenium, and beta-carotene against oxidative damage in rat liver slices and homogenate

Male Sprague-Dawley (SD) rats were fed a vitamin E and selenium deficient diet and diets supplemented with vitamin E, selenium, beta-carotene, and a combination of the three. Tissue slices and homogenate of liver were incubated at 37 degrees C with and without the presence of prooxidants. The effect of vitamin E, selenium, beta-carotene, and the combination of the three antioxidants on the oxidative damage to rat liver tissue was studied by measuring the production of oxidized heme proteins in both tissue slices and homogenate during spontaneous and prooxidant-induced oxidation. The diet with the combination of all three antioxidants showed a strong protective effect against oxidative damage to heme proteins in contrast to the antioxidant-deficient diet. In general, diets with vitamin E, selenium, and beta-carotene were less effective than the combination of all three antioxidants. The protective effect of antioxidants on the heme protein oxidation was correlated with their inhibitory effect on lipid peroxidation measured as the production of thiobarbituric acid-reactive substance (TBARS). The protection of antioxidants on heme proteins was also dependent on the type of oxidation inducer. Possible mechanisms of antioxidants against oxidation in liver tissues are discussed.

A seasonal eosinophilic dermatitis in cats

Twenty cats from Nelson with distinctive crusting and erosive dermatitis of the nasal bridge and histological lesions of eosinophilic dermatitis, often with collagenolysis, were examined in 1990 and 1991. Four of the cats also had pinnal dermatitis and five had eruptive lesions on the chin. The condition was intermittent and seasonal, occurring in summer and autumn. It is probable that the lesions were caused by hypersensitivity to insect bites, as has been demonstrated in a similar clinicopathological syndrome recently recognised in Australia.

Habits and rituals

On-going restructuring in the Danish care for the elderly is to a very high degree based on recognition of the significance of habits and rituals, as well on the knowledge of what is needed to alter them. Habits and rituals are concepts that are often confused in everyday patterns of thought. It is necessary to be able to distinguish between the two concepts before change can be effected. To varying degrees people are characterised by unconscious and conscious habits as well as inherited and personal rituals. Personal development, age, support from one's surroundings, and so on, determine the degree to which a person may continue or alter acquired patterns of habit and ritual.

Nitric oxide exchange in nitrosylmyoglobin

The exchange of nitric oxide in nitrosylmyoglobin, the heme pigment of nitrite-cured meat, has been studied using nitrogen-15 labelling in aqueous solution under conditions (pH, concentration of ascorbate and nitrite) similar to those prevailing in meat during the curing process, and has been found to have a half-life of approximately 2 h at 40 degrees C. One nitric oxide molecule is coordinated to the iron(II) centre of a myoglobin molecule and, in weakly acidic aqueous solution under anaerobic conditions, the exchange rate of the bound nitric oxide is proportional to the concentration of nitrosylmyoglobin, nitrite and hydrogen ion. The rate of exchange has a moderate temperature dependence, corresponding to an activation barrier of delta H+- = 47 +/- 3 kJ.mol-1 at 25 degrees C and pH 5.9, a value dramatically lower than that found for the enthalpy of activation for the oxidation of nitrosylmyoglobin by molecular oxygen, delta H+- = 110 kJ.mol-1. The difference in temperature dependence between the exchange and the autoxidation is discussed in relation to the function of nitrosylmyoglobin as antioxidant in cured meat products.

Development of rancidity in salmonoid steaks during retail display. A comparison of practical storage life of wild salmon and farmed rainbow trout

The quality of wild salmon and farmed rainbow trout from aquaculture, both packed in transparent vacuum-skin packaging, was followed during storage for 6 months in an illuminated freezer cabinet (product temperature -17 degrees C, half of the packs protected against light, and half of the packs fully exposed to light), combining (a) colour determination of the carotenoid-pigment flesh by tristimulus colorimetry, (b) determination of thiobarbituric-acid-reactive substances (TBA value), (c) carotenoid analysis and, at the end of the storage experiment, (d) sensory evaluation. Rancidity developed faster in steaks of wild salmon (TBA increased during 6 months of storage from 2.8 mumols malonaldehyde/kg flesh to 12.5 mumols/kg for light-protected packages, and to 17.6 mumols/kg for packages exposed to fluorescent light) as compared to steaks of farmed rainbow trout (TBA increased from 1.2 to 5.8 mumols/kg, independent of light exposure), a finding also confirmed by sensory evaluation. In both products, the carotenoid pigment was identified as astaxanthin; salmon steaks, the product more susceptible to developing rancidity, had the lower astaxanthin content (rainbow trout 9.1 mg/kg flesh, salmon 4.9 mg/kg, prior to storage). While the astaxanthin content remained virtually constant in salmon steaks during storage, the content decreased significantly in steaks of rainbow trout, an observation which suggests the role of astaxanthin as a sacrificial protector against radical processes.

[Treatment with rectal diazepam or acetylsalicylic acid in effervescing tablets in ambulatory cervical curettage and biopsy. A double-blind randomized study]

A double-blind randomised investigation with placebo control was undertaken to investigate the effect of 10 mg diazepam rectally or 1 g acetyl salicylic acid as effervescing tablets on pain and nervousness during and after outpatient cervical curettage and biopsy from the vaginal cervix or the cervical endothelium. A total of 97 women participated and were subdivided at random. Three patients were, however, excluded as they did not participate as planned. No differences were found between the three groups as regards pain and nervousness during the intervention and fatigue and drowsiness after the intervention. No statistically significant difference was found in the degree of satisfaction with the treatment in the various therapeutic groups.

Tibial hypo-/aplasia with preaxial syn- and polydactyly

Tibial hypo-/aplasia with preaxial syn- and polydactyly is a rare autosomal dominant condition. Fewer than 20 cases have so far been described. One is presented here.

The ischaemic leg: a long-term follow-up with special reference to the predictive value of the systolic digital blood pressure. Part II: After arterial reconstruction

Ninety-five patients with 122 legs with a systolic blood pressure on the big toe below 30 mmHg were the subject of arterial reconstructive surgery. Investigating the limb survival rate we found the systolic blood pressure on the big toe to be the most important predictor, whereas there was found no predictive value of the ankle pressure/index. Preoperative clinical symptoms, which are closely related to the digital blood pressure, were significant predictors of the limb survival rate: the low-pressure limb with no symptoms or intermittent claudication had a significantly higher survival rate than the limb with rest pain and/or gangrene. Following arterial reconstructive surgery the social fate of patients with threatened legs was fairly good as 83% became fully independent.