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Biomedical subjects

K Bell

Publications and source records attributed to K Bell.

At least 163 records · Page 9Linked to original sources
PubMed1989

Brahman bull fertility in a north Australian rangeland herd.

Low and variable bull fertility was identified as a constraint on reproductive rates in beef cattle grazed in an extensive, multiple sire mating regimen on Mount Bundey station in the Darwin pastoral district of northwestern Australia. Erratic conception patterns were attributed to a high proportion of bulls with low breeding soundness evaluation scores (BSE), a high proportion of aged bulls (40%>8 yr), and to running bulls of mixed age groups. Liveweight, scrotal circumference (SC) and age were positively correlated. An experiment was subsequently designed to investigate the ability of a number of bull measurements to predict fertility in an extensively-managed, multiple-sire mating system. Blood typing was used to match calves to sires. It proved to be an accurate and useful technique which successfully identified the parentage of 94% of calves examined. Single measurements of serum testosterone after administration of gonadotrophin-releasing hormone (GnRH) were not correlated with fertility. However six of the seven most fertile bulls exhibited high peak serum testosterone levels in summer, and lower levels in the winter. In contrast, the less fertile bulls did not exhibit seasonal variation in GnRH-induced serum testosterone levels. Social dominance ratio was weakly related to fertility (r=0.51: P<0.05). BSE (r=0.51: P<0.05) and SC (r=0.49: P<0.05) prior to, but not subsequent to, mating were correlated with bull fertility. Under the conditions of this experiment, a bull to cow ratio of 1:20 was excessive for bulls with a satisfactory BSE score.

Journal Article↗
PubMed1988

Subdivision of equine Tf into H1 and H2.

Subdivision of equine TfH into two variants, designated H1 (faster) and H2 (slower), has been accomplished by high voltage, thin layer polyacrylamide gel electrophoresis at pH 7.9. Transferrin H1 and H2 have been shown to be controlled by codominant alleles and gene frequencies of the Tf alleles have been determined in the Australian Thoroughbred, Standardbred. Quarter Horse and Arabian Horse breeds.

Alleles↗
PubMed1988

Studies on the procurement of blood coagulation factor VIII. In vivo studies on blood components prepared in half-strength citrate anticoagulant.

To determine the viability of blood cells collected in half-strength (0.5 CPD.A2) and full-strength citrate anticoagulants, paired crossover autologous survival studies were performed in normal volunteers using 51Cr-labelled red cells after 35 days storage and 111In-labelled platelets after 5 days storage. For both studies, viability was better maintained in 0.5 CPD.A2 anticoagulant. This was significant for red cells (24-hour survival: 80 +/- 6 vs. 52 +/- 21%) but not for platelets by either linear or multiple-hit models (recovery 51 +/- 13 vs. 38 +/- 14%, survival 5.1 +/- 1.4 vs. 3.7 +/- 1.5 days). The poor viability of red cells after storage in full-strength anticoagulant was associated with low cellular adenosine triphosphate levels and was confirmed in follow-up studies.

Adenine↗
PubMed1988

Studies on the procurement of blood coagulation factor VIII. In vitro studies on blood components prepared in half-strength citrate anticoagulant 18 hours after phlebotomy.

Our previous studies have shown that the use of half-strength citrate anticoagulant improves plasma factor VIII stability while maintaining the viability of red cells and platelets. This study extends these observations to show that the stability of factor VIII is maintained in blood stored at room temperature or 4 degrees C overnight and that in vitro tests indicate comparable quality of red cells and platelets prepared from half-strength citrate donations processed immediately or after overnight storage at room temperature. The exception to this was a more rapid loss of red cell 2,3-diphosphoglycerate, as has previously been observed for full-strength citrate donations.

Blood Platelets↗
PubMed1988

Acute phase response in the horse: plasma protein changes associated with adjuvant induced inflammation.

The induction of an acute phase response in four horses by adjuvant administration was used to examine the effect on the levels of plasma proteins. Blood parameters (packed cell volume, total plasma protein, red blood cell count, haemoglobin concentration) were monitored to follow the progress of the acute phase response in parallel with the examination of plasma proteins. Plasma protein levels were determined by densitometry from the electrophoretic patterns of three different gel systems. Haptoglobin and alpha 1 B glycoprotein were shown to be positive acute phase reactants whereas albumin was a negative acute phase reactant. Plasma esterase and proteins of the Pi system did not change following the experimental inflammation.

Acute-Phase Reaction↗
PubMed1987

Tammar wallaby plasma protease inhibitory (Pi) proteins.

Electrophoretic examination (isoelectric focusing and polyacrylamide gel electrophoresis) of 157 plasmas from a Kangaroo Island population of tammar wallabies (Macropus eugenii) resulted in the identification of five putative condominant protease inhibitor alleles, F, I, M, P and S, which exhibited microheterogeneity due to variable terminal sialic acid content. The frequencies of the five alleles in this population were 0.041(F), 0.682(I), 0.194(M), 0.073(P) and 0.010(S). The proteins had isoelectric points in the pH range 3.94-4.38, Mr of 60,500 to 66,000 and were identified as protease inhibitors by their abilities to inhibit both trypsin and chymotrypsin. Protein blotting of the denatured proteins demonstrated cross reaction with antiserum to human alpha 1-protease inhibitor.

Alleles↗
PubMed1987

ISO-DALT characterization of 12 'new' equine plasma protease inhibitor (Pi) alleles.

Twelve equine protease inhibitory alleles, PiE, H, J, K, L2, O, P, Q, R, V, X, Z, have been characterized in terms of isoelectric point, molecular mass and inhibitory activity to bovine trypsin and chymotrypsin by ISO-DALT electrophoresis. Protein maps for 20 Pi alleles including those of the eight 'Thoroughbred' alleles (PiF, G, I, L, N, S1, S2, U) have now been determined. Five pairs of alleles, S1/S2, G/K, L/L2, P/R and U/Z, possessed varying numbers of common proteins ranging from one protein in the case of G/K and L/L2 to six in the case of U/Z. Based on these results and studies of the abnormal expressions of PiF, PiL and PiS1, a theory of at least three closely linked loci has been postulated to account for the marked heterogeneity of the equine protease inhibitory system.

Alleles↗
PubMed1987

Frequencies of plasma protease inhibitor alleles in Australian horse breeds and the recognition of two new alleles.

Investigation of the plasma protease inhibitor system (Pi) in the Arabian and quarter horse breeds and re-examination of the standardbred breed resulted in the recognition of two new Pi alleles, designated E and L2. PiE is rare and has been found in only three quarter horses. In contrast, PiL2 is relatively common in the standardbred (0.107) and allowed subdivision of PiL into PiL and PiL2. Splitting of PiL resulted in an exclusion probability (PE) of 0.649 for the standardbred Pi system. Frequencies of the Pi genes have now been determined for four breeds (thoroughbred, standardbred, quarter horse and Arabian) of horses in Australia.

Alleles↗
PubMed1986

The equine protease inhibitory system (Pi): abnormal expressions of PiF, PiL, and PiS1.

Three cases of abnormal expression of the equine protease inhibitory alleles, Pi F, L, and S1, were observed following the examination of 30,000 plasma samples by one-dimensional acid (pH 4.6) polyacrylamide gel electrophoresis. Characterization of the abnormal proteins in terms of isoelectric point, molecular mass, inhibitory spectra, and sialic acid content was performed using one- and two-dimensional electrophoretic techniques. The Pi F and S1 abnormalities were postulated to be the result of amino acid substitutions causing alterations in the processing of the carbohydrate side chains. No explanation could be offered for the Pi L abnormality other than a charge shift mutation. Abnormal types, F*, L*, and S1* behaved as alleles but the distribution of L* in offspring from one stallion (present in only 6 of 83 offspring) differed significantly from expectation.

Alleles↗
PubMed1986

School accidents.

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Accidents↗
PubMed1985

The occurrence of the feline A blood group antigen on lymphocytes.

Sera from 300 cats were tested for the presence of anti-lymphocytic antibodies. One hundred and nineteen sera showed some activity with the majority (79) reacting only with lymphocytes from blood group A cats. Absorption of two such sera with A, AB and B erythrocytes and absorption of AB system reagents with lymphocytes from A and B blood group cats demonstrated that the A antigen is expressed on both erythrocytes and lymphocytes. Blood group and lymphocyte typing tests of foetuses indicated that the A antigen is present on these tissues as early as 46 days gestation. The erythrocytic B antigen could not be demonstrated on lymphocytes although a single antiserum, which reacted against lymphocytes from group B cats, was found. Several sera containing anti-lymphocytic antibodies which were not related to the AB type were also detected.

Animals↗
PubMed1984

Interspecific chimerism--the characterization and immunological responsiveness of Bos taurus-Bos indicus haemopoietic chimeras produced by embryo transfer.

Bos taurus-Bos indicus twin calves were produced by embryo transfer and their degree of haemopoietic chimerism and immune responsiveness examined. All 10 pairs of Friesian-Brahman twins were chimeric compared with only 6 out of 12 pairs of Jersey-Brahman twins. In the Friesian-Brahman twins, Friesian lymphocytes predominated in all calves while in the Jersey-Brahman twins there was no uniform dominance of one cell type over another. All calves that had chimeric lymphocyte populations were also erythrocyte chimeras, although in two pairs of twins the genotype of the erythrocytes was different from the genotype of the lymphocytes. The lymphocytes of all chimeric calves failed to respond in mixed lymphocyte culture (MLC) tests to the lymphocytes of their co-twins but gave vigorous responses to cells from other calves. Primary and secondary immune responses to keyhole limpet haemocyanin (KLH) antigen were studied in the efferent prefemoral lymph in normal Jersey, Friesian and Brahman calves, in 1 set of Jersey-Brahman twins and in 5 sets of Friesian-Brahman twins. The immune responses of chimeric twins with genetically identical lymphocyte populations were quite dissimilar and were characteristic of the somatic genotype of the calf and not of the genotype of the lymphocyte population. The chimeric status of the cell population in the lymph did not change significantly during the response. These results suggest that either the genetic capacity of a population of lymphocytes to recognize and respond to antigens can be modified during ontogeny in an alien genetic environment or that a crucial determinant of the final outcome of an immune response is not the immunocompetent cell itself but the physiological and anatomical environment in which it exists.

Animals↗
PubMed1984

The plasma protease inhibitor system (Pi) of Standardbred horses.

The plasma protease inhibitor system (Pi) of Standardbred horses was studied by thin-layer, high-voltage, acid polyacrylamide gel electrophoresis (pH 4.6) followed by protein staining and staining for trypsin and chymotrypsin inhibition. In addition to the eight Thoroughbred alleles (PiF, G, I, L, N, S1, S2, U), another 10 alleles, designated PiH, J, K, O, P, Q, R, V, X, Z, were postulated to account for the 98 Pi types which were observed in Standardbreds. Detailed inhibitory spectra of the 'new' alleles were determined and further exceptions to the Pi1, Pi2 classification of Juneja et al. (1979) were found. Limited family data demonstrated the genetic nature of the 'new' variants and confirmed the allelic inheritance of the 'new' Pi variants.

Alleles↗
PubMed1984

Relationships between the bovine major histocompatibility system and commonly recognized erythrocyte and serum polymorphisms.

Linkage at a recombination frequency of 0.10 or less between the bovine major histocompatibility system and the B, C and L red blood cell groups and the albumin, haemoglobin and transferrin loci was excluded by Morton's lod score method. The white blood cell antigen CA19, which is independent of the bovine major histocompatibility system, is the J blood group.

Animals↗