Regional variation in the hedonic evaluation of lamb meat from diverse production systems by consumers in six European countries.

This paper describes the responses of consumers in six European countries (Greece, Italy, Spain, France, Iceland and United Kingdom) tasting meat from twelve different local types of lambs produced in those same six countries. Animals represented 10 breeds and crossbreeds, three sexes, several diets composed of either milk, concentrates and various forages as main ingredients and different slaughter ages, from 1 and 12 months, and carcass weights, from 5.5 to 30.4kg. Tests were conducted by 36 volunteer families in each of the six countries involved in the study. Families were asked to roast the joints using their own cooking criteria, evaluating (from "dislike extremely" to "like extremely") flavour, tenderness, juiciness and overall liking. Also the cook was asked to rate the odour during cooking. Country and lamb type and their interaction were statistically significant for all the variables analysed. Results suggest a link between the assessments of a given lamb type and the consumers' culinary background, showing clear associations between country and lamb type preferences. It was possible to separate, independently of the country, different groups of families with similar preferences. Five family groups, which included 88 families (40.74%), had a clear Mediterranean origin and preferred types of lamb fed either milk or mainly concentrate diets. Seven family groups, which included 93 families (43.06%) with a clear northern origin, preferred types reared on grass or with grass included in the diet. The rest of the groups (four) that included 35 families (16.20%) had no clear composition (northern or Mediterranean), and they had a wider taste preference. It can clearly be seen that there are two categories of consumers of lamb in the analysed European market: those who prefer "milk or concentrate taste" and those who prefer "grass taste".

In situ surface oxidation study of a planar Co/SiO2/Si(100) model catalyst with nanosized cobalt crystallites under model Fischer-Tropsch synthesis conditions.

The oxidation of nanosized metallic cobalt to cobalt oxide during Fischer-Tropsch synthesis (FTS) has long been postulated as a major deactivation mechanism. In this study a planar Co/SiO(2)/Si(100) model catalyst with well-defined cobalt crystallites, close to the threshold value reported for oxidation in the literature (4-10 nm), was prepared by the spin coating method. The planar Co/SiO(2)/Si(100) model catalyst was characterized with atomic force microscopy, X-ray photoelectron spectroscopy, and Rutherford backscattering. The surface oxidation behavior of the nanosized metallic cobalt crystallites of 4-5 nm was studied using in situ near-edge X-ray absorption fine structure under model FTS conditions, i.e., H(2)/H(2)O = 1, P(Total) = 0.4 mbar, and 150-450 degrees C. No surface oxidation of metallic cobalt was observed under these model FTS conditions over a wide temperature range, i.e., 150-400 degrees C.

Synergy, activity and tolerability of zidovudine and interferon-alpha in patients with symptomatic HIV-1 infection: AIDS Clincal Trial Group 068.

Thirty-four subjects with symptomatic HIV-1 infection, p24 antigenaemia, and CD4 cell counts > 200/mm3 were randomly assigned to receive treatment with either zidovudine (ZDV) orally, interferon-alpha (IFN-alpha) subcutaneously, or both at respective low (200 mg ZDV/ 2 million international units IFN-alpha (MIU)), middle (400 mg/4 MIU) or high (600 mg/6 MIU) daily dose levels for 12 weeks. Thereafter, all patients received combination therapy at the initially assigned dose level to a total of 96 weeks. This design permitted analysis by the combination index (CI) method, which demonstrated antiretroviral synergy between ZDV and IFN-alpha with respect to p24 antigen suppression. Over the first 12 weeks, combination therapy was acceptably tolerated, more so than IFN-alpha monotherapy, and it was significantly more active in suppressing antigenaemia than either of the monotherapies. Similarly, the high-dose combination was the most active dose level over weeks 12 to 96. Combination ZDV/IFN-alpha at the optimal dose level defined by this trial merits further study. In addition, the CI design strategy employed here may be useful for the investigation of new antiretroviral combinations.

Integrin expression in uveal melanoma differs from cutaneous melanoma.

PURPOSE: During the process of metastasis, changes in cell-cell and cell-matrix contacts occur; therefore, expression of integrins, a superfamily of adhesion molecules, may be important. Expression of integrins has been studied extensively in cutaneous melanoma. Because it is known that uveal melanoma has a metastatic behavior different from cutaneous melanoma, the authors investigated integrin expression in uveal melanoma. METHODS: The authors used monoclonal antibodies recognizing integrin subunits alpha 1-6, alpha v, beta 1, and beta 4 and integrins alpha v beta 3 and alpha v beta 5 on frozen sections of 32 human primary uveal melanomas and 4 metastases, followed by an avidin-biotin-peroxidase complex-immunoperoxidase technique. RESULTS: As in cutaneous melanoma, alpha 4 expression was rare, but most lesions expressed alpha 3 and alpha 6. In contrast to cutaneous melanoma, in which alpha 2 is well expressed in most lesions and alpha 5 is expressed only in a small percentage of lesions, alpha 2 expression was rare in uveal melanoma and alpha 5 expression was found in all lesions. A major difference was observed with regard to the alpha v beta 3 vitronectin receptor. In contrast to cutaneous melanoma, in which alpha v beta 3 is expressed in advanced primary melanomas and metastases, alpha v beta 3 was not detected in any of the primary uveal melanomas, but all lesions strongly expressed alpha v beta 5. CONCLUSIONS: Integrin expression in uveal melanoma cannot be correlated with cell type or invasiveness. In contrast to cutaneous melanoma, it seems that determination of the integrin expression profile is not suitable for categorizing uveal melanomas as less malignant and highly malignant lesions.

Impact of asymptomatic congenital cytomegalovirus infection on size at birth and gestational duration.

Cytomegalovirus (CMV) is the most common viral agent causing congenital infection in humans, affecting 0.2 to 2.4% of all live births. Symptomatic congenital CMV infection has previously been shown to cause low birth weight and prematurity. Whether or not asymptomatic congenital CMV infection, which represents the majority of cases (90 to 95%), affects intrauterine growth or gestational duration is unknown. Using a population of 146 infants with asymptomatic congenital CMV infection and 1419 controls from two socioeconomically diverse populations (biracial low income and white mid- to upper income), determinants of body size (birth weight and crown-heel length) were investigated using multiple regression techniques. We found that congenital infection following the transmission of maternal primary and "unknown" CMV infection resulted in a significant mean birth weight deficit of 163 g (P less than 0.04) for the low income term infants (blacks and whites), but not in the mid- to upper income white infants. Newborns with congenital infection following the transmission of maternal reactivated (recurrent) CMV infection were significantly shorter by a mean of 1 cm (P less than 0.03) than controls, a finding that was consistent regardless of socioeconomic status or race.

Expression of CD44 and the pattern of CD44 alternative splicing in uveal melanoma.

In cutaneous melanoma, the standard CD44 molecule is abundantly expressed, whereas the expression of certain splice variants is related to tumour progression and to the metastatic potential of the cell line. In the present study we have investigated the expression of CD44 and the pattern of CD44 alternative splicing in uveal melanoma in relation to the cell type, diameter and invasiveness of the tumour. All uveal melanomas strongly stained with antibodies to the standard portion of CD44. No expression of the CD44 variant (v) exon CD44v7 was found, whereas v5, v6 and v10 were expressed (in 2/12, 5/12 and 8/12 cases, respectively). No correlation was observed between expression of particular splice variants and cell type, tumour diameter or invasion of the sclera or Bruch's membrane. All three uveal melanoma cell lines tested were strongly CD44 positive and expressed low levels of v6-containing isoforms at the cell surface, but v5, v7 and v10 were absent. Our results show that CD44 is strongly expressed in uveal melanoma and that the pattern of CD44 alternative splicing is similar to that observed in cutaneous melanoma. However, in uveal melanoma this alternative splicing does not appear to be related to prognostic parameters.

Meat quality traits in the emu (Dromaius novaehollandiae) as affected by muscle type and animal age.

Meat quality traits were determined in the major muscles of the emu (Dromaius novaehollandiae) at different slaughter ages (6, 10, 14, 17 or ≥20 months). A mean ultimate pH value of 5.5 was reached within around 3 h post mortem, but this value was 6.1 in animals that had suffered a preslaughter stress (transportation and fasting). The collagen and pigment contents varied widely among the muscles. The protein and pigment contents increased with animal age, but this effect was perceptible only between 6 and 14 months. The other chemical constituents were little affected by muscle type or animal age. The intense red colour of emu meat, due to a high pigment content, was very sensitive to oxidation, thus limiting the storage of fresh meat under aerobic conditions to short periods of time. Despite a rapid post-mortem tenderization (≤24 h), the residual myofibrillar strength obtained after extended ageing remained intermediate between those reported for chicken and beef. The tenderness of meat, cooked to 60 °C, differed between muscles and decreased with increasing age, thus reflecting the changes occuring in the concentration and in the heat stability of the intramuscular connective tissue.

Relationships between muscle characteristics and meat quality traits of young Charolais bulls.

Charolais bull calves (106) were used to study the variability in meat quality attributes in relation to the variability in muscle characteristics in the Longissimus thoracis (LT) muscle. The variability in traits was adjusted either to constant age or constant weight at slaughter and thus originated only from differences between animals born, reared and fattened in the same location. The following meat quality attributes were measured: the strength of the myofibrillar resistance to a 20% compression strain measured on the raw meat 2, 7 and 21 days post mortem; and taste panel scores of tenderness (initial and overall), flavour and juiciness of steaks grilled to a 55°C core temperature 6 or 15 days post-mortem. The following muscle characteristics were measured 24 h after slaughter: pH, dry matter, protein, lipid, heme iron and collagen contents, collagen solubility, LDH and ICDH activity, the proportion of slow twitch myosin heavy chain, the mean muscle fibre area and the mean sarcomere length. One fourth to one third of the variability of 2 day mechanical strength and 15 day tenderness or flavour scores were related to the variability in muscle characteristics. Tenderness and strength measurements were predominantly related to the muscle fibre area, collagen characteristics and energetic metabolic activity. Dry matter content was the principal muscle characteristic related to flavour.

Performance, muscle composition and meat texture in veal calves administered a ß-agonist (clenbuterol).

The effect of clenbuterol administration on performance, muscle composition and meat texture was studied in veal calves. Three groups, of ten animals each, were assigned to the three following treatments for 27 days: control, administration of 0·3 and 1·0 ppm in the feed (dry matter basis). After a 14-day withdrawal period, the animals were slaughtered, and three muscles were sampled (M. longissumus thoracis; M. triceps brachii caput longum; M. rectus abdominis). During the period of clenbuterol administration, the treated calves exhibited a higher daily liveweight gain (DLWG) and a higher feed conversion efficiency (FCE) compared to those of the control calves, but these effects were reversed during the subsequent withdrawal period. At slaughter, the overall DLWG, FCE and carcass weight were similar in the three treatments, but the dressing percentage in the clenbuterol-treated calves was up to 5·7 points higher than that of the control calves. In the muscles studied, the clenbuterol had little effect on pH, sarcomere length, dry matter and nitrogen contents, collagen heat stability (solubility, isometric tension) or cooking loss; but it markedly reduced the content of lipids, collagen and haem pigments. The clenbuterol also affected myofibrillar strength after ageing, measured either on raw meat or on cooked meat. This was particularly evident in cooked meat which showed up to a two-fold increase in mechanical parameters (maximum stress, compression modulus) after the clenbuterol treatment. No dose effect was detected except for the mechanical parameters. It was concluded that clenbuterol administration affects, meat in two opposite ways, viz. a marked toughening effects, due to a reduction in the muscle ageing rate, that is not compensated by a concomitant tenderizing effect (through a decrease in the intramuscular collagen content).

Perimysial collagen crosslinking and meat tenderness in Belgian Blue double-muscled cattle.

The relationship between intramuscular collagen and five collagen crosslink concentrations, and the tenderness of meat from Belgian Blue normal, heterozygous double-muscled (DM) and homozygous DM cattle was investigated using M. semitendinosus (St) and M. gluteobiceps (Gb). The histidinohydroxymerodesmosine (HHMD) concentration (per mol collagen) in St was less in DM animals than normal animals. Concentrations (per gram of wet meat) of HHMD and Erlich chromogen (EC) in Gb, and HHMD, EC, dihydroxylysinorleucine (DHLNL) and hydroxylysinorleucine (HLNL) in St were also lower in DM animals than normal animals. Shear force of raw meat was significantly greater in normal animals than DM for both muscles; cooked meat shear force was greater in the normal animals for the Gb muscles only, showing a good correlation with sarcomere length. Most correlations between shear force and collagen or crosslink concentrations were not significant and those that were highly significant were generally weak.

Tenderization of beef by lactic acid injected at different times post mortem.

The potential to tenderize beef muscles by the injection of lactic acid (0.5 M, 10% w/w) was studied using the pectoralis profundus muscle from cull cows. The injection was performed either 1 h (pre rigor) or 24 h (post rigor) post mortem, and the meat was stored for 2 or 14 days post mortem. Both treatments caused a rapid pH drop to around 5.0 within 4 h of injection. Other effects were: (1) an accelerated release of lysosomal enzymes into the cytosol; (2) a greater degradation of myosin heavy chains; (3) ultrastructural alterations of the myofibrils which included a general weakening or rupture in the M-lines and, to a lesser extent, in the I-bands; (4) a decreased heat stability of perimysial collagen indicated by a lower insoluble collagen content, lower differential scanning calorimetry transition temperature, and lower transition temperatures in isometric tension tests on muscle strips. The lactic acid injections improved significantly the textural traits of the meat (shear value, tensile strength, sensory scores) at 2 days post mortem with little further improvement when storage was extended to 14 days post mortem. Changes in texture were of similar amplitude at both post mortem injection times. The tenderization mechanisms of lactic acid injection are discussed.

Effect of feed protein on carcass composition and meat quality in steers.

Forty-five Charolais steers were fed one of four experimental regimes containing maize silage and maize grain supplemented with either protected soyabean-rapessed meal or linseed meal. The first three regimes were formulated to supply the same energy and different protein levels with soyabean-rapessed meal: low (L-SRM), medium (M-SRM) and high (H-SRM). The fourth regime consisted in feeding the same amount (kg/day) of linseed meal as that of soyabean-rapessed meal in the H-SRM regime (LSM). As the protein level increased from L-SRM to H-SRM, the daily weight gain of steers increased and the carcass composition was changed towards higher muscle and lower fat proportions. Though the actual supply of feed protein by regime LSM was close to that achieved with M-SRM, the effect of linseed meal supplementation on weight gain and carcass composition was comparable to that obtained by feeding the high protein level (H-SRM). The dry matter content increased and the heme pigments and lipids contents decreased in longissimus thoracis muscle as the protein supply increased from the low to the high level. Again the amplitude of the differences in meat quality with L-SRM were similar in H-SRM and LSM. Muscle colour, connective tissue and mechanical strength remained practically unaffected by the protein treatments. However, meat was scored less tender in H-SRM and less juicy in treatment LSM than in treatment L-SRM. The results obtained with linseed meal suggest a specific effect of type of feed protein on beef carcass composition and meat quality.

Effects of high-intensity high-frequency ultrasound on ageing rate, ultrastructure and some physico-chemical properties of beef.

High-intensity and high-frequency ultrasound was tested for its ability to accelerate meat ageing and increase beef tenderness. Samples (≈50g) of semimembranosus muscles from 8 cull cows were assigned to ultrasonic treatment (2.6MHz; 10W/cm(2); 2 ×15s) either pre-rigor (day 0, pH 6.2) or post-rigor (day 1, pH 5.4). When applied pre-rigor, ultrasound induced a slight delay in rigor mortis onset, a stretching (12-15%) of the sarcomeres (p<0.05), an ultrastructural alteration in the Z-line region and an immediate increase (around 30%) in the release of calcium in the cytosol (p<0.05). However, no conclusive effect on meat ageing rate was observed. Post-rigor ultrasonic treatment did not induce any structural modification but slightly improved the ageing index after 6 days (p<0.05). However, no improvement in the final (day 14) ageing index was observed compared to the controls. As ultrasound had also no effect on the thermal stability of collagen, at both postmortem times, no improvement in meat tenderness can be expected under the conditions used.