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Biomedical subjects

S N Brown

Publications and source records attributed to S N Brown.

At least 37 records · Page 2Linked to original sources
PubMed2000

Reversible defects in natural killer and memory CD8 T cell lineages in interleukin 15-deficient mice.

C57BL/6 mice genetically deficient in interleukin 15 (IL-15(-/-) mice) were generated by gene targeting. IL-15(-/-) mice displayed marked reductions in numbers of thymic and peripheral natural killer (NK) T cells, memory phenotype CD8(+) T cells, and distinct subpopulations of intestinal intraepithelial lymphocytes (IELs). The reduction but not absence of these populations in IL-15(-/-) mice likely reflects an important role for IL-15 for expansion and/or survival of these cells. IL-15(-/-) mice lacked NK cells, as assessed by both immunophenotyping and functional criteria, indicating an obligate role for IL-15 in the development and functional maturation of NK cells. Specific defects associated with IL-15 deficiency were reversed by in vivo administration of exogenous IL-15. Despite their immunological defects, IL-15(-/-) mice remained healthy when maintained under specific pathogen-free conditions. However, IL-15(-/-) mice are likely to have compromised host defense responses to various pathogens, as they were unable to mount a protective response to challenge with vaccinia virus. These data reveal critical roles for IL-15 in the development of specific lymphoid lineages. Moreover, the ability to rescue lymphoid defects in IL-15(-/-) mice by IL-15 administration represents a powerful means by which to further elucidate the biological roles of this cytokine.

Animals↗
PubMed2000

Charge effects on oxygen atom transfer.

The rhenium(V) complex [(HCpz3)ReOCl2]+ ([1]+), the tris(pyrazolyl)methane analogue of the known tris(pyrazolyl)borate complex (HBpz3)ReOCl2 (2), has been prepared. The two complexes are strikingly similar, as are the phosphine oxide adducts [(HCpz3)ReCl2(OPPh3)]Cl ([3]Cl) and (HBpz3)ReCl2(OPPh3) (4), which have been characterized by X-ray crystallography. Comparison of the bimolecular reduction of [1]BF4 and 2 by triarylphosphines reveals a pronounced charge effect, with the cationic species being reduced by PPh3 about 1,000 times faster than its neutral analogue in CH2Cl2 at room temperature. Ligand substitution of the adducts [3]+ and 4 is dissociative, with the cationic complex dissociating phosphine oxide about 56 times more slowly than the neutral compound. The relative impact of charge on ground and transition states in atom transfer reactions is discussed.

Journal Article↗
PubMed2000

Variation in the colour of broiler breast fillets in the UK.

1. The normal range in colour of broiler breast muscle was assessed using an objective (instrumental) measure of colour in portioned breast fillets at a commercial processing plant. In addition, the relationship between colour and ultimate muscle pH (pH(ult)) was also examined. 2. Considerable variation in colour was evident although minimal inter-flock variation was found. The exceptions were 2 free range flocks which produced breast fillets significantly lighter and less red. 3. Extremes of colour are likely to be discriminated against at the point of purchase. 4. A clear relationship between pH(ult) and L* values was found which provides more evidence for the existence of a PSE like condition in broiler breast meat.

Animals↗
PubMed1999

Relationship between food deprivation before transport and aggression in pigs held in lairage before slaughter.

Pigs from three farms were deprived of food for up to one hour, 12 hours or 18 hours before being sent for slaughter. In lairage, the animals' behaviour was monitored, and at slaughter a blood sample was collected and analysed for cortisol, lactate and creatine phosphokinase, potential indicators of stress and physical activity. The carcases were assessed for skin damage as an index of fighting, and rigor in the hind leg as an indicator of stress and/or fatigue. Measurements were also made of cold carcase weight, backfat thickness and liver glycogen concentration. General activity was very high on entry to the lairage pen. Drinking and mounting occurred almost immediately. Fighting developed after an exploratory period, and could last up to 60 minutes. There were large differences in the behaviour of pigs from the three farms. Pigs from farm A fought frequently but showed little mounting activity, whereas pigs from farm C were involved in mounting but little fighting. The period of food deprivation had no effect on average skin damage or rigor score, but the frequency of carcases with the highest scores was different The pigs deprived of food for up to an hour had the lowest incidence of severe skin damage and high rigor scores. Boars had a higher incidence of severe skin damage but a lower incidence of carcases with a high rigor score than gilts. Liver glycogen was almost completely depleted in the pigs deprived of food for 12 and 18 hours and was lower in the pigs deprived for up to an hour than in animals fed immediately before slaughter. The period of food deprivation had no effect on the levels of cortisol, creatine phosphokinase or lactate in the blood.

Abattoirs↗
PubMed1999

Effects on cattle of transportation by road for up to 31 hours.

The physiological and behavioural effects on cattle of transporting them for periods of 14, 21, 26 and 31 hours, including a stop for a rest and drink on the lorry after 14 hours, were studied in 120 transported animals and 48 control animals. The physiological measurements indicated that a journey lasting 31 hours was not excessively physically demanding, but many of the animals chose to lie down after approximately 24 hours. The animals that lay down had higher plasma cortisol levels than those that remained standing. Many animals chose not to drink during the rest stop. Physiological measurements made after the journeys indicated that 24 hours in lairage, with hay and water freely available, allowed the animals to recover substantially, although not completely, irrespective of the journey time.

3-Hydroxybutyric Acid↗
PubMed1999

Behavioural and physiological responses of pigs to being transported for up to 24 hours followed by six hours recovery in lairage.

Ninety-six pure-bred Large White pigs weighing 80 to 100 kg were either not transported or transported for eight, 16 or 24 hours, and then either slaughtered immediately on arrival at the abattoir or kept in lairage for six hours before being slaughtered. The pigs travelling for eight, 16 or 24 hours lost 2.2, 2.0 and 4.3 per cent of liveweight, respectively, and the pigs travelling for 24 hours lost 2.6 per cent of hot carcase weight Both liveweight and hot carcase weight recovered during the lairage period although there was a net liveweight loss in comparison with the control animals. Only transport for 24 hours led to losses in carcase weight The concentration of non-esterified fatty acids increased with the time spent travelling. The concentrations of cortisol, creatine phosphokinase and lactate were all low in comparison with the levels found in commercially slaughtered animals. Plasma albumin and protein concentrations indicated that the animals were becoming dehydrated during the longer journeys. The animals lay down for most of the journey and appeared to be asleep. During the period in lairage, the animals transported for eight hours had two distinct periods of feeding and drinking but spent most of the time lying down, but those transported for 16 and 24 hours showed far more eating and drinking activity. All the groups appeared tired, but the urge to eat of the groups transported for 16 hours, and especially 24 hours appeared to be more important. There were behavioural and the physiological differences between the transported groups and the controls. Six hours in lairage with access to food and water allowed most of the physiological parameters to return to pretransport levels.

Animals↗
PubMed1999

Effects of lairage time on body temperature and glycogen reserves of broiler chickens held in transport modules.

Commercial broiler chickens killed in two processing plants, one in the south of England, the other in Scotland, in two seasons (winter and summer) and on two occasions in each season, were used to investigate the effects of killing the birds immediately on arrival or holding them in lairage for one, two, three or four hours. The two most important consequences of holding the birds in lairage were that their body temperature increased and their liver glycogen was depleted. The body temperature increased with the time they were held in lairage, although most of the increase occurred in the first hour and the increase was greater in summer when ambient temperatures were higher. Liver glycogen depletion became apparent after about one to two hours in lairage. No evidence was obtained that the birds were significantly dehydrated or physically stressed by being kept longer in lairage.

Animal Welfare↗
PubMed1999

Effect on young calves of a one-hour feeding stop during a 19-hour road journey.

This study examined the effects of transporting calves less than four weeks of age on a journey at the limit of the maximum time laid down by recent EU legislation. In both summer and winter, 45 calves were transported by road for 19 hours. The journey included a one-hour break on the lorry in which the calves were given either a glucose/electrolyte solution, water, or nothing at all. Control groups of 15 calves remained on farm and were fed normally. The effects of the journey were greater during winter when liveweight loss was greater and more prolonged, and the calves suffered a depression in body temperature. Mid-journey feeding was of minimal benefit. Feeding electrolytes reduced the extent of dehydration as measured by changes in plasma total protein and albumin concentrations, but there was some indication that giving water alone was detrimental. Most of the variables which changed during the journey had recovered in line with the values in the control animals within 24 hours of the end of the journey, but the calves' liveweight and plasma creatine kinase activity took up to seven days to stabilise. The study highlighted the problem that young calves have in maintaining body temperature during transport, especially during colder weather.

Animal Feed↗
PubMed1999

Effects of preslaughter handling on the behaviour, blood biochemistry and carcases of farmed red deer.

Eight groups of six red deer (four groups of males and four groups of females) were held overnight in an unfamiliar paddock, after which they were moved into a holding pen and slaughtered sequentially by stunning with a captive bolt pistol in a restraining pen. On entering the restraining pen, half the deer in each group were stunned immediately, but the other half were stunned after 10 minutes. Deer spent much of the initial period in the holding pen standing stationary in 'alert' postures, but became less alert over time. A significantly higher proportion of males than females were observed in alert 'head-up' postures in the restraining pen. Deer held in the restraining pen for 10 minutes had significantly higher plasma cortisol concentrations than those which were stunned immediately. Females had a significantly higher glycogen concentration postmortem in both the liver and semimembranosus muscle than males, and deer held in the restraining pen for 10 minutes had a significantly lower liver glycogen concentration than deer which were slaughtered immediately. Males had significantly higher semimembranosus muscle pHu values than females, although the differences were small, and of the 14 deer with pHu values above 6-0, 11 were males.

Abattoirs↗
PubMed1998

Ambient temperature below which pigs should not be continuously showered in lairage.

Showering pigs with cold water during preslaughter lairage is thought to be useful in reducing the body temperature of hot, easily stressed animals. However, showering when the ambient temperature is too low could chill them too severely. To assess the effects of showering and to determine a temperature below which pigs should not be showered, pigs from one source, passing through a commercial slaughterhouse lairage, were split into two groups of approximately 50 each, showered and unshowered, on 10 days with a range of ambient temperatures. The pigs' behaviour and any damage to their skin were recorded, various measures of body temperature were taken before and after showering, and blood taken at slaughter was analysed for plasma creatine kinase, cortisol and lactate. Showering prevented the usual reduction in activity observed in pigs in lairage at high ambient temperatures. On the basis of the reduction in their flank temperature during showering, it is recommended that pigs should not be showered continuously if the temperature inside or outside the lairage falls below 5 degrees C, and showering should cease if they are seen to be shivering.

Abattoirs↗
PubMed1998

The genomic organization of Isopeptidase T-3 (ISOT-3), a new member of the ubiquitin specific protease family (UBP).

A novel Isopeptidase T gene (ISOT-3) has been identified on human mosome 3q26.2--q26.3. gene shows 67.3% nucleotide identity and 54.8% amino acid identity to n Isopeptidase (ISOT-1). Northern blot analysis has shown that ISOT-3 is highly essed in ovary and testes, low-level expression in six other tissues tested. In contrast, ISOT-1 is essed at high levels in brain, and there is no detectable expression in ovary. The exonic nization of these two genes highly conserved with only one variant intron position. Intron 15 in -3 is absent in ISOT-1, there is an alternate splice site at the same location. Although the --intron structure has been erved between the two genes, ISOT-3 has significantly larger intronic ons, and the overall of this gene is at least 90 kb compared to 15 kb for ISOT-1. These data suggest that both ISOT-1 and ISOT-3 have descended from a common ancestor. In addition, the low overall sequence identity and different expression patterns may reflect differences in substrate specificity.

Amino Acid Sequence↗
PubMed1998

Effects of stocking density on lambs being transported by road.

Lambs were transported for 24 hours during summer and winter at a range of stocking densities. Shorn lambs of mean liveweight 39.5 kg were transported at densities of 0.448, 0.513, 0.602 and 0.769 m2/100 kg in July and fully-fleeced lambs of 37.3 kg mean liveweight were transported at densities of 0.613, 0.680, 0.775 and 0.909 m2/100 kg in February. Fewer lambs lay down and rested at high stocking densities and there was a marked increase in the plasma levels of creatine kinase at the highest stocking density in winter. All other measured effects of stocking density were small when compared with the overall effects of transport. There was a decrease in body temperature during transport, especially in the lambs that were recently shorn, even though they were transported during warm summer conditions. At the highest stocking density there was a smaller decrease in body temperature.

Animal Welfare↗
PubMed1997

Effects on calves less than one month old of feeding or not feeding them during road transport of up to 24 hours.

Two trials, each involving 56 calves less than one month old, demonstrated that the responses of calves to food and water deprivation during 24 hours of transport were similar to those observed in older cattle and lambs. There was increasing utilisation of body reserves and a measurable increase in dehydration, coupled with an increased loss of liveweight. Feeding 1 litre of glucose/electrolyte solution at eight-hour intervals did reduce the effects of food and water deprivation, but it is suggested that the minor benefits of mid-transport feeding during a 24-hour journey would not justify the disruption that would be caused by unloading and feeding. It would be better to complete the journey in as short a time as possible, providing the calves were carried under suitable conditions. Liveweight and the levels of plasma beta-hydroxybutyrate, non-esterified fatty acids, total protein and albumin had all returned to approximately pre-transport values after 24 hours of recovery. However, the calves had not started to gain in liveweight until some time after 24 but before 72 hours of recovery. The calves did not show the same marked responses in heart rate, plasma cortisol and plasma glucose that are observed in older cattle and in other species. They also appeared to be unable to regulate their body temperature closely, when they were transported during the winter. It is suggested that their lack of response to transport was not because they were unaffected but because they were physiologically unadapted to coping with transport.

Adaptation, Biological↗
PubMed1997

Effects of the duration of lairage following transportation on the behaviour and physiology of farmed red deer.

Eight groups of five farmed red deer were transported by road for three hours, after which they were either slaughtered immediately (TO) or held in lairage for three, six or 18 hours (T3, T6 and T18). Liveweight loss increased with lairage time but hot carcase weight was unaffected. Deer spent much of the initial period in lairage standing stationary in 'alert' postures. After eight to 10 hours the proportions of time spent in various postures (standing stationary, moving and lying down) were similar to pre-journey values. None of the blood components associated with dehydration (packed cell volume, osmolality, total protein and sodium) changed significantly with lairage time. Compared with T0 deer, plasma creatine kinase activity was significantly decreased in T18 deer. Lairage time had no effect on skin damage, bruising or muscle glycogen content, although liver glycogen content increased with longer lairage time. Although lairage time had a statistically significant effect on muscle pHu (with T6 deer having the lowest values), the differences were small and none of the carcases had a pHu greater than 6-0.

Abattoirs↗
PubMed1997

Potential effect of vibration during transport on glycogen reserves in broiler chickens.

Subjection of broiler chickens to random, narrow band vibration (2, 5, 10 Hz) for 1 h, simulating that experienced during normal road transport, did not significantly influence liver or muscle glycogen concentrations or muscle ultimate pH (pHu). Vibration for 3 h increased body temperature (P<0.05) and decreased (P<0.01) pHu in both 'white' pectoralis superficalis (PS) and 'red' biceps femoris (BF) muscles overall, but did not affect liver or muscle glycogen concentrations. However, higher vibration frequencies resulted in reduced (P<0.05) glycogen concentrations in liver and BF muscle. The conclusion was that vibration was unlikely to be the major cause of muscle glycogen depletion seen in transported broilers, but the reduction in pHu in the PS muscle after vibration may have been related to the similar effect seen in previous studies after normal transport.

Animal Husbandry↗
PubMed1996

Effects of feeding, watering and resting intervals on lambs transported by road and ferry to France.

Three lorry loads, each of approximately 530 lambs, were monitored during August 1994 while they were transported from the Midlands to France. Each lorry underwent a similar journey, designed to study the effects of a) 22 hours on a lorry broken by two hours of feed, water and rest after 15 hours, b) 34 hours on a lorry broken by eight hours of feed, water and rest after 24 hours and c) 24 hours on a lorry and lairage for the following 48 hours. Measurements were made on 180 lambs in each load, of liveweight, plasma betahydroxybutyrate (BHB), non-esterified fatty acids (NEFA), urea, total protein, albumin, osmolality, creatine kinase (CK), cortisol and glucose, before, during and after transport. Twenty-four hours of transport resulted in changes in some of the variables measured that were little different from those observed after 24 hours of feed and water deprivation; however, the high ambient temperatures during the transport resulted in a greater degree of dehydration. For journeys longer than 15 hours a two-hour rest in lairage with access to water and a palatable food source was beneficial in allowing some slight recovery. Although all the differences were in the direction that would be expected with recovery, they were often small and, within the sensitivity of the study, were only significant for NEFA and C.K. For journeys longer than 24 hours, an eight-hour rest in lairage with access to water and a palatable food source was beneficial and allowed material realimentation and rehydration before further transport for up to 10 hours. After 24 hours of transport, however, liveweight, plasma urea, total protein and albumin had only returned to basal levels after 24 hours in lairage and plasma BHB, CK and osmolality after 48 hours of lairage.

3-Hydroxybutyric Acid↗