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Biomedical subjects

R Halliday

Publications and source records attributed to R Halliday.

At least 55 records · Page 3Linked to original sources
PubMed1980

The relatioship between serum immunoglobulin levels and specific antibody production in cows.

Antibody responses were measured, by the Farr ammonium sulphate technique, to two unrelated antigens-human serum albumin and sperm whale myoglobin. Differences between cows in their mean responses to both antigens were highly significant (P less than 0.001) but there were no differences between Jerseys and Friesians. Preinoculation IgG1, IgG2 and IgM levels were correlated with subsequent specific antibody production. The most significant relationship was between total immunoglobulin (IgG1 plus IgG2 plus IgM) and specific antibody production (r=0.76, P less than 0.01). But there was a negative correlation between the total Ig levels and the relative avidities of the antibodies produced (r=-0.65). These data suggest that in antibody production there is a balance between quality and quantity; cows with normally high serum immunoglobulin concentrations generally produce more antibody in response to challenge but this increase only compensates for the relatively lower avidity of their antibody for the antigen.

Animals↗
PubMed1979

The absorption of immunoglobulin from colostrum by bottle-fed lambs.

Factors affecting the absorption of immunoglobulin from colostrum by new born lambs were studied. Merino, Scottish Blackface, Cheviot, Southdown, Border Leicester, Finnish Landrace and Finnish Landrace x Dorset Horn lambs were removed from their mothers before sucking and bottle-fed with measured amounts of colostrum, either from individual ewes, or from pools of colostrum, some of which had been frozen for up to two years. Afterwards the lambs were fostered onto other ewes or reared on milk substitute. Their serum IgG1 concentrations before and after colostrum intake, were compared with IgG1 concentrations in conventionally reared lambs. The concentrations in lambs given a single feed of 150 to 200 g 1 hour after birth, or 30 g/kg at 1 hour and 7 hours compared favourably with those in control lambs. Lambs fed 50 to 100 g at 1 hour had a high proportion of very low concentrations and lambs fed 30 g/kg at 1 h, or at 1 and 24 h had low mean concentrations but no very low individual concentrations. The concentrations after a feed at 1 hour were positively correlated with the total amounts of IgG1 in the colostrum and negatively correlated with the birth weights. Only very small amounts were absorbed at 24 hours. Absorption was more efficient in males than in females and in Cheviots than in other breeds. It was unaffected by the age of the colostrum. Similar proportions of bottle-fed and control lambs died before 6 months of age, but relatively more bottle-fed lambs died from respiratory infections. The IgG1 concentrations and growth rates of the bottle-fed lambs were not significantly correlated.

Absorption↗
PubMed1978

Time shift evoked potentials (TSEPs): method and basic results.

A simple technique for generating averaged evoked potentials to auditory signals that appear to move in space is described. Shifts in the apparent location of the signal were created by digitally delaying the output of a white noise generator with a minicomputer. The two channels were reconverted to two analog signals and presented binaurally through headphones. Shifts inthe apparent location of the signal produced a time shifted evoked potential (TSEP) that was not present during monaural control runs. TSEP amplitudes were largest near the vertex and varied as a function of the presentation format.

Acoustic Stimulation↗
PubMed1978

The effects of passive antibodies to egg albumin on active immunity in lambs to Brucella abortus and egg albumin.

The long-term effects of colostrum on active immunity to two unrelated antigens are described. Lambs were fed with pooled colostrum--to equalise passive immunity--with or without added antibodies to egg albumin (Ea). There were significant breed differences in the response both to Brucella abortus measured at one month of age, and to Ea, measured at three months of age, although there was no significant correlation between the responses to the two antigens, either within or between breeds. Surprisingly, whereas antibodies to Ea caused a four-fold reduction in antibody production to B abortus, they did not affect the overall mean response to Ea. But the timing of the response to Ea was significantly affected, suggesting that the low persisting concentrations of antibody had caused qualitative changes in the response.

Animals↗
PubMed1978

Effects of energy intake during late pregnancy and of genotype on immunoglobulin transfer to calves in suckler herds.

Blue-Grey (Shorthorn x Galloway) and Hereford x Friesian cows were given levels of feeding, during the last 12 weeks of pregnancy, varying between 75.2 per cent and 171.5 per cent of the maintenance requirements in one experiment and between 65 per cent and 125 per cent of the maintenance requirements in a second experiment. The concentrations of the immunoglobulin classes IgG1, IgG2 and IgM, in their colostrum and in their calves' serum were measured. The IG1 and IgM, but not the IgG2, concentrations were significantly higher in the Blue-Grey than in the Hereford x Friesian colostrum and serum. The relative concentrations of the three classes in the serum were almost identical to those in the colostrum, suggesting that absorption by the calves was non-selective. The amounts of immunoglobulin transferred to the calves were not affected by the cows' levels of feeding in the first year, but there was a small increase in transfer with increasing levels of feeding during the second year. Cows that transferred large amounts to their calves in the first year tended to do so in the second year. The milk intake and growth of the calves during the first 42 days were significantly correlated with their immunoglobulin concentrations.

Animals↗
PubMed1978

Variation in immunoglobulin transfer from ewes to lambs.

The IgG1 concentrations in two-day-old lambs were significantly correlated with litter size, date of lambing, length of gestation and age of the dam. When these and other effects were allowed for significant breed differences were found, the concentrations being relatively high in Finnish Landrace, Welsh Mountain and Soay lambs, and relatively low in Border Leicester, Oxford Down and Southdown lambs. The concentrations in crossbred lambs were related to those in the parent breeds. The effects of the various factors on the yields of colostrum and total IgG1 by ewes were similar to their effects on the lamb serum concentrations. The yields were highly correlated with milk production. The heritabilities for IgG1 concentration in lambs and for total IgG1 production by ewes were estimated at 0.10 and 0.45, respectively.

Animals↗
PubMed1978

Immunoglobulin concentrations in Scottish Blackface lambs on a hill farm.

The serum immunoglobulin concentration in one- to 11-day-old Scottish Blackface lambs born outdoors on a hill farm were very similar to those in Scottish Blackface lambs born indoors on an experimental lowland farm. The concentrations were significantly higher in single lambs than in twins, and in lambs which survived for six months than in lambs which died, and showed significant annual variations which could not be related to the weather. They were significantly correlated with the ages of the dams, the lambs' gains in weight to weaning, but not with the weights or ratios of weights of the lambs and ewes after lambing, nor with the birth-coat types of sexes of the lambs. There were wide variations in the capacities of the abomasums at birth.

Animals↗
PubMed1978

The role of colostrum antibodies and the significance of antigenic competition in young lambs.

Young lambs were fed with a small amount of pooled colostrum and injected at either 1, 3, 6 or 12 weeks after birth with the antigen hen egg albumin (Ea). Five days before the Ea injection the experimental group were given a large dose of pooled vaccines (competing antigens). Blood samples were collected at regular intervals after the Ea injection. The results showed marked antigenic competition of Ea at both 6--and 12--weeks of age but the results were partially confounded by the presence of unexpected passive antibodies to Ea in the pooled fed. The experiment was repeated with a separate group of conventionally reared lambs given the same competing antigens but using human serum albumin (HSA) as the suppressed antigen. In this experiment the results differed since antibody concentrations and avidities to HSA were similar in 1, 6 and 12-week-old animals and there was no evidence for antigenic competition. The data presented illustrate the difficulties both of measuring immune responses in young ruminants and also of interpreting such results.

Animals↗
PubMed1976

Variations in immunoglobulin concentrations in Finnish x Dorset Horn lambs.

The serum immunoglobulin concentrations in two-day-old Finnish x Dorset Horn lambs, which were born and nursed indoors, were high and unrelated to littersize, except when young ewes had large litters, or when ewes lambed twice in a year. The results contrast sharply with those from Merino and Blackface lambs, examined previously, whose mean concentrations were much lower, and generally fell substantially with increasing litter-size. The superiority of the Finnish x Dorset Horn sheep in this respect is attributed to the ability of the lambs to suck particularly vigorously, shortly after birth, especially when large litters are compared, and to a higher rate of colostrum production by the ewes. The correlations between the immunoglobulin concentrations in the lambs and their growth and survival were significant but slight.

Age Factors↗
PubMed1976

Passive immunity in the lamb. Effects of a second feed of colostrum on antibody absorption from the first feed.

Lambs were taken from their mothers before sucking and fed pooled colostrum (30 g/kg body weight), containing added antibody to egg albumin, 1 h after birth. At 4 h after feeding there was a two-fold range in immunoglobulin (IgG) concentration and a sixteen-fold range in anti-egg albumin activity in their sera. The coefficient of correlation between the IgG and antibody concentrations was significant but low (r = 0.445, P less than 0.02). When a second feed of colostrum without added antibody was given 6 h after the first, both the IgG and the antibody concentrations increased significantly, indicating that there had been increased absorption from the first feed, rather than absorption from the second. The increases in IgG had a significant negative correlation with the IgG concentrations before the second feed (r = 0.760, P less than 0.001). Sera from control lambs fed only untreated colostrum gave only trace, probably non-specific, antibody reactions. The results suggest that single feeds of colostrum are generally inefficient, and that the passive immune status of young lambs may be improved and made more uniform by subsequent feeds, even though these may be themselves deficient in IgG.

Animals↗
PubMed1967

Rehabilitation and the narcotic addict: results of a comparative methadone withdrawal program.

The purpose of this retrospective study was to compare (1) regular methadone withdrawal treatment and (2) prolonged methadone withdrawal treatment in 105 and 71 voluntary patients respectively, who attended the Narcotic Addiction Foundation (N.A.F.) between 1959 and mid-1964. Treatment consisted of individual counselling and medical care for all, and only residential care and psychiatric assessment for selected cases. The number of treatment sessions and the details of drug therapy are described.One hundred and fifty-three of 176 patients (87%) were interviewed approximately one to five years after the first clinic contact. Forty-three per cent showed some overall improvement in their behaviour. Rehabilitation was defined as change in a specific area-drug use, work, criminal behaviour, community associations, friendship patterns and family relationships-rather than in terms of abstention from drugs only. Age affected comparative results.

Adolescent↗