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Biomedical subjects

M A Holmes

Publications and source records attributed to M A Holmes.

At least 37 records · Page 2Linked to original sources
PubMed1997

Immunoepidemiology of the equine tapeworm Anoplocephala perfoliata: age-intensity profile and age-dependency of antibody subtype responses.

The equine intestinal cestode Anoplocephala perfoliata has been the subject of recent epidemiological and immunological studies because of its suspected association with intestinal disease in the horse. We have previously shown that the IgG(T) subtype antibody response to the 12/13 kDa component of the parasite excretory/secretory (E/S) antigen is positively correlated with parasite intensity. In this study, we utilize that correlation to examine the changes in natural infection intensity with age. Infection intensity based on IgG(T) responses showed a triphasic age-dependency pattern with peak mean worm burden in the 6 months-2 years age group, falling to a lower plateau level from 3 to 15 years, and rising again in older age groups. Anti-E/S total IgG was found to have a convex age-dependency curve, with maximal response in the 6 months-2 years old age group. IgG(a) showed a triphasic response similar to the age-intensity profile of IgG(T); IgG(c) showed steadily increasing levels of antibody with age. The IgG(b) age-dependency profile was intermediate between IgG(a) and IgG(c). Age-specific correlation coefficients between anti-12/13 kDa IgG(T) (as a measure of infection intensity) and IgG(a) and IgG(b) revealed statistically significant values for many age groups. The relative importance of exposure to infection and the development of acquired immunity as determinants of the observed age-intensity pattern is considered.

Age Factors↗
PubMed1997

Use of Rhodococcus equi virulence-associated protein for immunization of foals against R equi pneumonia.

OBJECTIVE: To evaluate use of the virulence-associated protein of Rhodococcus equi in immunizing foals against R equi pneumonia. ANIMALS: Eight (experimental group) and 6 (controls) mares with their foals. PROCEDURE: Virulence-associated protein extracted from R equi was used to prepare an acetone-precipitated. Triton X-extracted (APTX) antigen. After determination of the efficacy of passive immunization, in untreated foals or in foals given plasma from a horse vaccinated with APTX antigen or from a nonvaccinated horse, a field trial was done to evaluate the efficacy of vaccination of 8 mares, twice with APTX before parturition, and of their foals at ages 3 and 5 weeks; 6 mares and their foals served as unvaccinated controls. All 2-day-old foals were given plasma from local donor horses inoculated with a locally produced bacterin. Serum opsonizing activity produced by vaccination with APTX was determined. Passively immunized foals were challenge exposed with an aerosol of virulent R equi. Foals of the field trial were exposed to enzootic R equi infection. RESULTS: Inoculation with APTX resulted in high IgG antibody liters with opsonizing activity. Passive immunization of foals with plasma from an immunized horse enhanced bacterial clearance from the lungs, compared with that in foals not given plasma or given plasma without APTX antibodies. Vaccination of mares and foals exposed to natural infection resulted in development of R equi pneumonia in 4 of 8 vaccinated foals, but in only 1 of 6 unvaccinated foals. CONCLUSIONS: Vaccination with APTX antigen led to high-titer, opsonizing antibody. Plasma from a vaccinated horse appeared to enhance clearance of R equi from the lungs of foals. Paradoxically, vaccination of mares and their foals with APTX antigen did not protect foals and may have enhanced R equi pneumonia in the foals.

Actinomycetales Infections↗
PubMed1997

[Demonstration of immunoglobulin isotypes in the vitreous body as a contribution to the etiology of recurrent equine uveitis].

The functional properties of different immunoglobulin isotypes in equine recurrent uveitis (ERU) has not been investigated yet. Here, we describe the quantitative determination of total immunoglobulin levels and isotype differentiation in the vitreous of four horses with ERU as compared to that of seven healthy horses. In contrast to almost equal amounts of total immunoglobulin in the vitreous of both groups, remarkable differences were found: All four of the horses with ERU had significantly higher IgA contents in their vitreous as compared to the control group. However, the other isotypes monitored (IgM, IgGa, IgGb, IgGc and IgG(T)) indicated no differences between both groups. Comparing the individual ratios of immunoglobulin isotypes in the vitreous and the autologous serum of two horses with ERU and two control animals provided informative results: IgM was only detected in serum but not at all in vitreous of all horses investigated. All four IgG isotypes monitored in the diseased animals as well as these IgG isotypes and the IgA in healthy animals were present in the same ratios in serum and in vitreous of the individual horses. In general, the content of such isotypes in the vitreous was about 1000 fold lower then the respective isotypes in the autologous serum. These results are compatible with a transfer of the IgG and IgA isotypes from the serum into the vitreous in healthy individuals. All four horses with ERU, however, had a selectively increased relative IgA content in the vitreous as compared to their serum. This argues for a preferential local IgA production within the framework of a local immunological reaction to antigens located within the eyes of horses with ERU.

Animals↗
PubMed1996

Computer-aided veterinary learning at the University of Cambridge.

An approach of computer-assisted learning in veterinary education at the University of Cambridge, involving the development of four types of learning module, is outlined. A tutorial on regional perineural anaesthesia in the horse, based on the familiar tape-slide format but with significant improvements, is described. A question and answer self-assessment package and a computer-based 'digital lecture' are also discussed, together with a case simulation involving the investigation of a polydipsic dog. All the tutorials were developed using standard software packages and image digitising processes. The philosophy behind the development of these computer-assisted learning packages is discussed.

Computer-Assisted Instruction↗
PubMed1996

Separation of equine IgG subclasses (IgGa, IgGb and IgG(T)) using their differential binding characteristics for staphylococcal protein A and streptococcal protein G.

Equine IgG possesses four well-defined subisotypes, designated IgGa, IgGb, IgGc and IgG(T) on the basis of their increasing anodal mobility in electrophoresis. However, the preparation of IgGa and IgGb reference proteins has not previously been reported. Certain bacterial cell wall proteins, termed protein A and protein G, have been used for purification of IgG subisotypes from the serum of domestic animals which, combined with other techniques utilising differences in the physico-chemical properties of the proteins, has allowed the purification of Ig isotypes. This paper describes purification of the subisotypes of equine IgG. Purification of IgGa and IgGb was achieved by the separation of a 'fall-through' peak from ion-exchange chromatography consisting of IgGa and IgGb into two fractions (peaks C and D) by FPLC protein A and protein G affinity chromatography. Peak C consisted of IgGb and peak D consisted of IgGa exhibiting slightly faster cathodal migration than peak C in IEP analysis. Affinity chromatography using protein A and G columns also indicated that there may be two different components of IgG(T); one with a low affinity for protein G and the other having a greater affinity for protein G.

Animals↗
PubMed1996

Energy and nutrient intakes in a sample of 136 Edinburgh 7-8 year olds: a comparison with United Kingdom dietary reference values.

Energy and nutrient intakes were assessed in 136 children, aged 7-8 years and living in and around Edinburgh, using the 7 d weighed inventory technique. The results were compared with UK dietary reference values (DRV) for energy, macronutrients and micronutrients. NSP intakes were compared with a calculated reference value (CRV). Mean energy intakes were close to the estimated average requirement for both boys and girls. Mean percentages of food energy derived from fat and saturated fat were high in relation to DRV (37 and 14 compared with 35 and 11 respectively). Mean percentage of food energy derived from total carbohydrate was close to the DRV of 50 but intakes of starch appeared to be low and intakes of total sugars high (23 and 26% food energy respectively). Superficially, this suggests that there is a need to alter the balance of carbohydrate in favour of increasing starch and lowering total sugar. There was, however, a clear 'fat-sugar seesaw', i.e. children with a high percentage energy from total sugars had a low percentage energy from fat, and vice versa. In view of this finding, it is possible that efforts to reduce total sugar intake in children may result in a further increase in percentage energy from fat. Mean intakes of NSP were only 50% of the CRV, but this guideline may be set too high. Mean intakes of most micronutrients were above reference nutrient intakes. Reported low intakes of Zn and Se were treated with caution due to the perceived incompleteness of the data for these in the nutrient database. The authors concluded that targeting high intakes of total fat and saturated fat should be the health priorities in this age-group.

Child↗
PubMed1996

The contribution of breakfast to the diets of a sample of 136 primary-schoolchildren in Edinburgh.

The contribution of breakfast to mean daily energy and nutrient intakes was investigated in a sample of 7-8-year-old children recruited by letter from five Scottish schools. After eighteen families dropped out of the study and three dietary records were discarded, the final sample numbered 136 (51%). Dietary data were collected using the 7 d weighed inventory, while a questionnaire was used to classify children into manual or non-manual social class groups. Mean daily energy intakes were close to estimated average requirements (Department of Health, 1991), while intakes of most micronutrients were in excess of reference nutrient intakes (RNI; Department of Health, 1991). The most popular breakfast consumed by the children was one including a ready-to-eat breakfast cereal (RTEBC). Differences in macronutrient content were seen between breakfasts of boys and girls, while manual-social-class children ate breakfasts which were lower in energy, NSP and certain micronutrients than those of non-manual-class children. Breakfast contributed 14% of energy and 9-36% of micronutrient intakes to the overall diets. Breakfasts including RTEBC contributed significantly more energy and nutrients than other types of breakfast. Children who ate RTEBC nearly every day had overall diets which had a higher nutrient density and were lower in fat than those of children who ate RTEBC less frequently or not at all. Intakes of most micronutrients were above the RNI in both these groups, with the exception of folate, Fe and vitamin A, which were below the RNI for those consuming RTEBC infrequently. However, the type of breakfast eaten did not appear to influence energy and nutrient intakes at other meals during the day. Nevertheless, it was concluded that breakfast, particularly one containing RTEBC, had a strong influence on the daily energy and nutrient intakes of 7-8-year-old children, particularly by reducing the proportion of energy from fat.

Child↗
PubMed1996

Relationships between social class, nutrient intake and dietary patterns in Edinburgh schoolchildren.

Social class may have an important influence on dietary intakes and health. Information on specific nutrient differences between children of high and low social classes may help explain health inequalities and identify target areas for nutrition education. In this study, energy and nutrient intakes were estimated in 136 7-8-year-olds, from a range of social backgrounds, using 7-day weighed inventories. A structured questionnaire was used to establish social class. Lower social class children had significantly lower daily intakes of many micronutrients, which nevertheless met dietary reference values, and a higher percentage energy from fat. In addition, lower social class children consumed less breakfast cereal, more full fat milk, were more likely to take school meals and received a greater proportion of energy and nutrients from snacks than higher social class children. Lower social class children were significantly shorter, but this association was independent of diet. The results suggest that lower social class children are a vulnerable group nutritionally. Nutrition education should focus on influencing the dietary patterns of lower social class children to favour a decrease in percentage energy from fat.

Body Height↗
PubMed1995

Functional studies of rat, porcine, and human pancreatic islets cultured in ten commercially available media.

There have been no extensive studies investigating the effect of tissue culture media on the in vitro functional characteristics of rat, porcine and human Islets of Langerhans. We therefore aimed to compare ten commercially available tissue culture media on the basis of their ability to maintain islet viability. Following isolation, islets were cultured free-floating in the ten media (RPMI 1640-11mM glucose (control), RPMI 1640-2.2mM glucose, Dulbecco's MEM, TCM 199, CMRL 1066, Iscove's MEM, Waymouth's MEM, Serum-Free medium, Ex-cell 300, Ham's F-12) and viability was assessed after 24 hr, 3 days, and 7 days on the basis of macroscopic appearance, cell membrane integrity, and insulin secretion in response to glucose stimulation both by dynamic incubation and by perifusion. Each islet species demonstrated physiological insulin release characteristics in all media--however, it was possible to distinguish between the media by comparing the stimulation indices calculated from the insulin release studies. Significantly higher stimulation indices were produced in Iscove's MEM for rat islets, in Ham's F-12 for porcine islets and in CMRL 1066 for human islets. Over the entire culture period a significant deterioration in function was observed in all species cultured in the control media, although this was reversed when islets were cultured in the optimal media. Furthermore, in the case of porcine and human islets a significant improvement in function over the seven-day period was noted in the optimal media. In conclusion, of the commercially available media, the optimal tissue culture medium for rat islets is Iscove's MEM, for porcine islets is Ham's F-12, and for human islets is CMRL 1066.

Animals↗
PubMed1995

Monoclonal antibodies specific for equine IgG sub-isotypes including an antibody which recognizes B lymphocytes.

Equine immunoglobulin G is currently classified as consisting of five sub-isotypes: IgGa, b, and c, IgG(T), and IgG(B). The study of the role of these immunoglobulins in antigen-specific responses, and the examination of their functional properties would be greatly facilitated by the availability of monoclonal antibodies (Mabs) that distinguish between them. The production and characterization of two Mabs that recognize an IgG sub-isotype with the characteristics of IgG(ab) is described. The immunoglobulin identified by these Mabs had a heavy chain weight of 53 kDa, was of rapid cathodal electrophoretic mobility in immuno-electrophoretic analysis, and reacted only with anti-sera to IgG, and not with anti-sera to IgG(T), IgA, or IgM in radial-immunodiffusion analysis. In addition, one of these two Mabs (CVS1) also recognized the majority of peripheral blood B lymphocytes in indirect immunofluorescent staining analysis, suggesting either that equine IgD may share a common antigenic epitope with an IgG sub-isotype, or that a large proportion of equine B lymphocytes may express an IgG sub-isotype on their surface.

Animals↗
PubMed1995

Confidential enquiry of perioperative equine fatalities (CEPEF-1): preliminary results.

The Confidential Enquiry into Perioperative Equine Fatalities (CEPEF-1) is an observational multi-institutional prospective study of recovery outcome at 7 days post operatively, as called for by Steffey (1991). Data from 6,255 general anaesthetics (February 91-March 93) were submitted confidentially by 62 clinics. The outcomes of 333 cases which were subjected to euthanasia and which were not classified 'alive' or 'died' at 7 days, were excluded from the analysis. The remaining 5922 cases were analysed to identify risk ratios (RR) between survivors and nonsurvivors for a variety of factors. These preliminary results indicate an overall death rate, for equine patients dying or being subjected to euthanasia within 7 days of a general anaesthetic because of perioperative complications, of 102/6255 (1.6%). This mortality rate decreased to 46/5220 (0.9%) when all colic surgery and delivery of foals under general anaesthesia were excluded. There was an increased risk for mares in the last trimester of pregnancy (RR = 6.4). Patients undergoing emergency abdominal procedures (colic patients and pregnant mares undergoing controlled or caesarean section delivery of foals) under general anaesthesia were at increased risk (RR = 12.9) compared to ear, nose and throat surgery. Within orthopaedic surgery, patients requiring internal fixation were at increased risk (RR = 3.2) compared to those undergoing miscellaneous orthopaedic surgery. There was no difference in risk between breeds. Patients not placed in dorsal recumbency were at reduced risk (RR = 0.3-0.5) compared to those which were in dorsal recumbency.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1995

Abnormal patterns of equine leucocyte differentiation antigen expression in severe combined immunodeficiency foals suggests the phenotype of normal equine natural killer cells.

Severe combined immunodeficiency (SCID) is a fatal autosommal disease of Arabian horses that leads to failure of maturation of T- and B-lymphocyte populations, although natural killer (NK) cells are unaffected. Thymic and lymph node tissues from two foals suffering from SCID were examined in an immunohistological study using a panel of monoclonal antibodies recognising equine leucocyte differentiation antigens. In both foals, the majority of cells in lymphoid tissues had an EqCD3-EqCD4-EqCD8+ phenotype, although rare EqCD3+ cells were also detected. The EqCD3-EqCD4-EqCD8+ cells may represent an abnormal lymphocyte differentiation product resulting from the SCID defect, or alternatively may be a normal equine NK cell population. We suggest that the evidence favours the latter proposal, and that equine NK cells in normal horses therefore may be identified by an EqCD3-EqCD8+ phenotype. The implications for the nature of the equine SCID defect are discussed.

Animals↗
PubMed1995

No adverse effects on growth seen in Scottish school children consuming either low fat diets or diets relatively high in non-starch polysaccharide.

This paper reports whether diets relatively high in non-starch polysaccharide (NSP) or those which meet Dietary Reference Values for percentage energy from fat are associated with poor growth and anthropometric status. Children aged seven to eight years (n = 136) were recruited from five schools in and around Edinburgh, selected randomly by Lothian Region's Education Department. Dietary intakes were estimated by their parents, using the seven day weighed inventory method. Height and weight were measured twice, with an interval of approximately 12 months, and expressed as standard deviation scores of 1990 UK population standards. There were no significant differences in mean height, weight, body mass index and height velocity between those children whose diets were relatively high in NSP or low in percentage energy from fat compared to the remainder of the sample. In addition, using multiple regression analysis, no associations were seen between growth and low fat diets or between growth and higher fibre diets. These results suggest that the low fat, higher fibre message can be applied to young children. However, further research is required to ensure that the results found in this sample apply to other groups of children.

Anthropometry↗
PubMed1994

Measurements of the electron dose distribution near inhomogeneities using a plastic scintillation detector.

PURPOSE: Accurate measurement of the electron dose distribution near an inhomogeneity is difficult with traditional dosimeters which themselves perturb the electron field. We tested the performance of a new high resolution, water-equivalent plastic scintillation detector which has ideal properties for this application. METHODS AND MATERIALS: A plastic scintillation detector with a 1 mm diameter, 3 mm long cylindrical sensitive volume was used to measure the dose distributions behind standard benchmark inhomogeneities in water phantoms. The plastic scintillator material is more water equivalent than polystyrene in terms of its mass collision stopping power and mass scattering power. Measurements were performed for beams of electrons having initial energies of 6 and 18 MeV at depths from 0.2-4.2 cm behind the inhomogeneities. RESULTS: The detector reveals hot and cold spots behind heterogeneities at resolutions equivalent to typical film digitizer spot sizes. Plots of the dose distributions behind air, aluminum, lead, and formulations for cortical and inner bone-equivalent materials are presented. CONCLUSION: The plastic scintillation detector is suited for measuring the electron dose distribution near an inhomogeneity.

Electrodes↗
PubMed1994

Further evidence of lead contamination of Omaha skeletons.

A previous analysis of Omaha skeletons dating between A.D. 1780 and 1820 revealed the presence of lead in all skeletons with high concentrations in children and adult males (Reinhard and Ghazi [1992] Am. J. Phys. Anthropol. 89:183-195). Two likely explanations for the high lead levels were presented: 1) metabolic absorption of lead and 2) diagenetic uptake of lead by the bones from postmortem application of pigments to the corpse. Two types of lead were available to the Omaha tribe: 1) Mississippi Valley type, and 2) non-Mississippi Valley type. It has been suggested that red-lead pigment mixed with mercury sulphide (cinnabar) applied to the corpse may have been one of the sources of lead found in bones. Further isotopic analyses of samples of pigment and metallic lead artifacts associated with the skeletons revealed that non-Mississippi Valley type lead is present in the pigment while Mississippi Valley type lead comes from metallic artifacts. Both lead and mercury were found in the pigment samples, verifying that a lead-based pigment mixed with cinnabar-based pigment was used as a cosmetic by the Omaha. Isotopic analysis of lead in skeletons indicates that the pigment contributed most to lead content of bone. This new evidence clarifies the previous study and suggests specific mechanisms by which lead became incorporated into bone.

Analysis of Variance↗
PubMed1994

Report of the First International Workshop on Equine Leucocyte Antigens, Cambridge, UK, July 1991.

The First International Workshop on Equine Leucocyte Antigens was organized and convened for the purposes of identifying immunologically relevant cell surface molecules of equine leucocytes and establishing a system of nomenclature for those molecules. Participating members of the workshop represented the majority of laboratories world-wide engaged in the tasks of production and characterization of equine leucocyte and lymphocyte markers using monoclonal antibodies. The workshop confirmed the identification of several equine CD molecules described previously by individual laboratories, and in addition recognized antibodies identifying new CD molecules. The workshop also succeeded in fostering co-operation between laboratories around the world which study equine immunobiology. Equine CD molecules identified by the current battery of monoclonal antibodies include EqCD2, EqCD4, EqCD5, EqCD8, EqCD11a/18, EqCD13 and EqCD44. Other antibodies are markers for MHC class I and class II molecules, for B cells, granulocytes, macrophages, T cell subsets distinct from those defined by CD4 and CD8, and other sub-populations of horse leucocytes that do not have obvious counterparts in humans, rodents, or other species. Despite the progress made in the first workshop, there are still substantial gaps in the armory of reagents available to study equine leucocyte biology, and further definition of the structure, function, and genetics of the antigens identified by the workshop clusters (WC1, WC2 etc.) and other molecules of immunological importance will be a goal of future workshops. The study of equine immunobiology and resistance to disease also urgently requires the development of tools to study equine immunoglobulins and cytokines, and these needs will provide ample scope for future studies.

Animals↗
PubMed1994

Polymorphic expression of an equine T lymphocyte and neutrophil subset marker.

This report describes the further characterization of a group of antibodies which have been assigned to Workshop Cluster 1 by the First International Workshop on Equine Leucocyte Antigens. These antibodies recognize a 22 kDa antigen, which is present on a large subset of T lymphocytes and neutrophils, and on medullary thymocytes. The antigen is polymorphic in its expression, and three equine phenotypes could be identified using the described antibodies. The function and homology of the antigen recognized by these antibodies are unknown.

Animals↗