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Biomedical subjects

C M Hawkey

Publications and source records attributed to C M Hawkey.

At least 19 recordsLinked to original sources
PubMed1994

Guidelines for the interpretation of laboratory findings in birds and mammals with unknown reference ranges: plasma biochemistry.

The results of analyses of plasma samples from healthy and sick adult birds and mammals of a wide range of species were used to calculate reference ranges and clinical ranges for 11 biochemical variables (calcium, sodium, chloride, total protein, albumin, globulin, inorganic phosphate, potassium, bicarbonate, urea and creatinine concentrations) in six mammalian Orders (Primata, Carnivora, Pinnipedia, Proboscidea, Perissodactyla and Artiodactyla) and six avian Orders (Ciconiiformes, Gruiformes, Pelecaniformes, Psittaciformes, Falconiformes and Strigiformes). The patterns of variation between Orders for the different biochemical variables were then used to provide guidelines for the interpretation of plasma biochemistry results in the species in these Orders for which there are no reference data. The observed clinical ranges provide an indication of the potential diagnostic value of each variable.

Animal Diseases↗
PubMed1991

Development of LYNX: a computer application for disease diagnosis and health monitoring in wild mammals, birds and reptiles.

IBM-compatible software has been developed so that quantitative and qualitative haematological and biochemical reference data for over 500 species of mammals, birds and reptiles can be made readily accessible to veterinary surgeons. The LYNX software makes it possible to retrieve these data at different taxonomic levels (species, genera, families, orders and classes) and to select data by age and sex. The data for each variable may be presented in the form of a reference range or as a frequency histogram. Notes describing the variations in blood cell morphology observed in healthy individuals of each species are included in the database. The user's own haematological and biochemical data can also be entered, stored and used.

Animals↗
PubMed1991

Erythrocyte size, number and haemoglobin content in vertebrates.

Relationships between erythrocyte number, size and haemoglobin content were examined in 441 species (101 families) of mammals, birds and reptiles. Whereas the total number of red cells (RBC), the mean cell volume (MCV) and mean cell haemoglobin (MCH) showed much variation, the haemoglobin level (Hb), packed cell volume (PCV) and mean cell haemoglobin concentration (MCHC) were relatively constant in all adult mammals and birds but lower in reptiles. There was a strong positive correlation between MCV and MCH and a strong negative correlation between MCV and RBC across all species. Mammals had more, smaller erythrocytes per unit volume of blood than birds, which, in their turn, had more, smaller erythrocytes than reptiles. The findings confirm that the oxygen-carrying capacity of the blood is highly conserved in birds and mammals but is lower in exothermic groups such as reptiles. Although the significance of the observed species differences in RBC and MCV has yet to be explained, the findings have considerable evolutionary, physiological and diagnostic interest.

Animals↗
PubMed1990

Haematology of clinically normal and sick captive reindeer (Rangifer tarandus).

A retrospective analysis of haematological values from clinically normal captive reindeer (Rangifer tarandus) showed that the red cell count, haemoglobin level, packed cell volume and lymphocyte count were higher and the erythrocyte sedimentation rate and eosinophil count were lower in juveniles than in adults. Newborn animals were anaemic compared with juveniles and adults and had high reticulocyte counts. The values from healthy reindeer were used to identify abnormal haematological variations in a number of sick animals. It was shown that reindeer exhibit similar haemopathological responses to those of other artiodactyla, with increases in the erythrocyte sedimentation rate and fibrinogen level being of particular diagnostic significance. Eosinophilia was the only abnormal haematological finding in individuals with subclinical infections of intestinal parasites.

Animals↗
PubMed1989

The elliptocyte: a study of the relationship between cell shape and membrane structure using the camelid erythrocyte as a model.

1. The elliptocytic shape of the camelid erythrocyte is very stable and has a high resistance to modification by drugs and treatment which alter the shape of the discocytic erythrocytes of scimitar-horned oryx and man. 2. Differences in the erythrocyte membrane proteins have been found which indicate that proteins play an important role in stabilisation of the camelid elliptocyte. 3. The organisation of the cytoskeletal network in camelid elliptocytes differs from that established for human discocytes.

Animals↗
PubMed1989

Age-related changes in the haematology of female F344 rats.

As little comprehensive baseline data are available on age-related haematological changes in genetically-defined rat strains, the haematology of female F344 rats is described in animals sampled at 2, 4, 8, 20, 66 and 121 weeks of age. Values for Hb, RBC and PCV increased from 2 weeks of age to reach adult levels at 8 weeks, whereas MCV, MCH and reticulocyte counts were high initially but decreased to reach the adult range at 8 weeks. Between 66 and 121 weeks, reticulocyte counts were significantly increased and values for MCHC significantly decreased. Lymphocytes were the predominant white cell type in each age group. The absolute numbers of neutrophils and lymphocytes showed slight variations between 2 and 66 weeks and both cell types increased significantly between 66 and 121 weeks. Platelet counts showed no overall age-related trends. Fibrinogen values increased from 2 weeks of age to reach the adult level at 8 weeks. One animal of the 14 sampled at 121 weeks showed changes in the blood, liver and spleen consistent with a diagnosis of lymphoid leukaemia.

Aging↗
PubMed1988

Haematological findings in budgerigars with megabacterium and Trichomonas infections associated with 'going light'.

Eighteen budgerigars with clinical signs of 'going light' were euthanased and examined post mortem; ingluvitis caused by Trichomonas gallinae infection was present in seven birds, proventriculitis associated with the presence of megabacteria in eight birds and in three birds both conditions were present. Haematological examinations of blood taken from the living birds showed that those with T gallinae infection had normal white cell counts whereas those in which megabacteria were present had significant leucocytosis and heterophilia. Some birds in both groups were anaemic. The findings suggest that infection with megabacteria may be responsible for a proportion of cases of 'going light' in budgerigars and that haematological examination can establish this diagnosis in living birds.

Animals↗
PubMed1988

Haematology of clinically normal and abnormal captive llamas and guanacoes.

Blood counts of healthy juvenile and adult llamas (Lama glama) and guanacoes (L guanacoe) showed that guanacoes have higher red cell counts, haemoglobin values and packed cell volumes than llamas. In both species, the numbers of lymphocytes and platelets were higher in juveniles than in adults. By reference to the values found in normal animals, abnormal haematological variations were detected in a number of sick individuals. Neutrophilia, hyperfibrinogenaemia and a tendency to develop regenerative hypochromic anaemia were observed in animals with acute and chronic inflammatory diseases and hypochromic macrocytic anaemia occurred in animals with parasitic infections. Many individuals in which subclinical intestinal parasitic infections were suspected had relatively high eosinophil counts although their other haematological values were normal.

Acute Disease↗
PubMed1988

Haemolytic effect of Pasteurella haemolytica on blood from young mammals.

On agar plates containing young lamb blood, Pasteurella haemolytica produces a wide outer zone of partial haemolysis in addition to the narrow zone of complete clearing seen on adult sheep blood agar. To determine whether this phenomenon was limited to lamb blood, samples from young animals of 20 mammalian species were examined. Two species--the barbary sheep (Ammotragus lervia) and scimitar horned oryx (Oryx tao)--possessed blood that gave this effect provided that the samples were taken from young animals. The 18 species that gave negative results included an ovine species, the bighorn sheep (Ovis canadensis).

Animals↗
PubMed1988

The importance of membrane stabilization in protecting the developing rat myocardium from the actions of triac.

Administration of triiodothyroacetic acid (triac) to pregnant rats produces cardiac hypertrophy and myofibrillar disarray in the hearts of the newborn offspring. Previous experiments have shown that concurrent administration of dl exprenolol or dl or d propranolol prevent the disarray but not the hypertrophy, suggesting that membrane stabilization and not beta-adrenergic blockade may be responsible for modifying the actions of triac. In order to clarify this, further experiments have been carried out whereby timolol, a beta-blocking agent with minimal or no membrane stabilizing activity, and procainamide, a pure membrane stabilizing compound, have been administered with triac. Timolol had no effect, but procainamide reduced the level of disarray and the hypertrophy to a minor degree. The results have thus confirmed the proposal that membrane stabilization is of major importance in modifying the actions of triac.

Animals↗
PubMed1987

Fibrinogen levels in mammals suffering from bacterial infections.

In a retrospective survey of fibrinogen levels and neutrophil counts in 388 blood samples from mammals suffering from bacterial infection, the combined results of the two tests provided positive confirmation of infection in a greater percentage of samples than did the results of either test alone. In Perissodactyla, Artiodactyla and Proboscidea, the fibrinogen level was abnormal more often than the neutrophil count. It was concluded that a fibrinogen estimation is a valuable addition to routine haematological screening procedures in mammals.

Animals↗
PubMed1986

Susceptibility of tamarin (Saguinus labiatus) red blood cell membrane lipids to oxidative stress: implications for wasting marmoset syndrome.

Captive Callitrichids frequently suffer a fatal wasting disease, wasting marmoset syndrome (WMS), of unexplained cause. This paper describes studies on the erythrocytes from animals in a breeding colony of tamarins (Saguinus labiatus), in which deaths from anaemia and wasting were occurring, to seek evidence for biochemical changes which could lead to oxidative damage and premature cell lysis. In only one animal of 33 studied did the red blood cell lipids show an increased susceptibility to oxidative damage. This animal, with some degree of certainty, could be diagnosed as having WMS. It was concluded that evidence for a primary deficiency of antioxidants as a cause of unexplained deaths, or WMS, in the colony could not at present be substantiated.

Animals↗
PubMed1986

Changes in red cell volume distribution frequency after acute blood loss in goats (Capra hircus).

Red blood cell volume distribution frequency, red cell counts, packed cell volumes and reticulocyte counts were monitored during recovery from severe haemorrhagic anaemia in goats. During the first three weeks after haemorrhage there was a small transient reticulocyte response and the cells produced were significantly larger than normal. These large cells persisted in the circulation as a distinct subpopulation of macrocytes, so that the rate of red cell production during this phase could be measured. The findings suggest that red cell volume distribution measurement is a useful method for retrospective diagnosis of severe haemorrhage and for monitoring recovery. The technique also provided a means of assessing erythropoietic activity in a species in which the reticulocyte response to red cell loss is minimal.

Animals↗
PubMed1986

Haematological reference values for adult pumas, lions, tigers, leopards, jaguars and cheetahs.

Normal haematological values and fibrinogen levels were obtained from a number of healthy adult Felidae in the collection of the Zoological Society of London. The group comprised 29 pumas (Felis concolor), 32 lions (Panthera leo), 27 tigers (P tigris), 19 leopards (P pardus), 18 jaguars (P onca) and 22 cheetahs (Acinonyx jubatus). The values provided a basis for identifying abnormalities in the blood of sick individuals of these species and for undertaking interspecies comparisons.

Acinonyx↗