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D W MacDonald

Publications and source records attributed to D W MacDonald.

At least 19 recordsLinked to original sources
PubMed2000

Isoform-specific exon skipping in a variant form of ClC-2.

A new form of the widely expressed, volume-regulated chloride channel, ClC-2, has been cloned from a pig ileal cDNA library. This ClC-2 homologue, called ClC-2i, has interesting variability within its cDNA sequence, including the deletion of bases that correspond to positions 1326 through 1401 in rat ClC-2 cDNA sequence. This 75 bp deletion corresponds to the complete loss of exon 13 plus the first four bases of exon 14, and involves an atypical intron-exon splice site. Tissue-specific mRNA expression patterns in the pig show variable degrees of exon 13 skipping in ClC-2i. Exon 13 skipping was also observed in rat ClC-2i, albeit at a higher frequency than in the pig in tissues that were examined. A relatively purine-rich 76 bp insertion in the pig genomic sequence of ClC-2i, close to the 3' end of intron 12, may be responsible for the relatively high frequency of exon 13 skipping during the processing of this mRNA.

Animals↗
PubMed2000

Coccidiosis in the European badger (Meles meles) from England, an epidemiological study.

In total 445 faecal samples were collected from 259 European badgers (Meles meles) in Wytham Woods, Oxfordshire, UK (462080). Microscopical examination revealed infection with 2 species of coccidia Eimeria melis and Isospora melis. From the initial examination of each animal, point prevalence rates of 0.44 and 0.35 were calculated for Eimeria and Isospora respectively. The intensity of infection was significantly greater for Eimeria than Isopora and the distribution of intensities was highly skewed for both species, with a few individuals shedding the majority of oocysts. Incidence and recovery rates for both coccidia species were calculated from longitudinal data collected at 3-monthly intervals from a subset of the adult badger population, and the predicted prevalence rates based on these were similar to the point prevalence rates. This suggests little, if any, parasite-induced mortality in the adult population. In contrast, there was a marked and significant reduction in the point prevalence and intensity of infection with Eimeria from cub to adult badger suggesting a degree of acquired immunity to Eimeria melis on initial exposure and/or that there is significant Eimeria-associated mortality in the cub population. No such relationship was found for Isospora infection. In those adult badgers with co-infections there was a direct relationship between the intensity of Eimeria and Isospora. The taxonomic status of these parasites suggests a heteroxenous life-cycle for I. melis, and direct transmission of E. melis. However, the greater than expected prevalence of co-infection is consistent with a common source of infection, such as communal latrines.

Age Factors↗
PubMed1999

Feline viruses in wildcats from Scotland.

Few data are available on the prevalence of feline viruses in European wildcats (Felis silvestris). Previous surveys have indicated that wildcats may be infected with the common viruses of domestic cats, apart from feline immunodeficiency virus (FIV). In the present study, 50 wildcats trapped throughout Scotland (UK) between August 1992 and January 1997 were tested for evidence of viral infection. All were negative for FIV by several serological or virological methods. By contrast, 10% of the cats were positive for feline leukemia virus (FeLV) antigen and infectious virus was isolated from 13% of a smaller subset. Of the wildcats tested for respiratory viruses, 25% yielded feline calicivirus (FCV) and although no feline herpesvirus was isolated, 16% of the samples had neutralizing antibodies to this virus. Antibodies to feline coronavirus (FCoV) were found in 6% of samples. Feline foamy virus (FFV) was an incidental finding in 33% of samples tested. This study confirms that wildcats in Scotland are commonly infected with the major viruses of the domestic cat, except for FIV.

Animals↗
PubMed1998

Phylogeographic patterns of feline immunodeficiency virus genetic diversity in the domestic cat.

Feline immunodeficiency virus (FIV) has a worldwide distribution among feral and domesticated cats and in many cases induces immunodeficiency disease analogous to that of human acquired immune deficiency syndrome. FIV is genetically homologous to human immunodeficiency virus (HIV) in both genome organization and gene sequence and, like HIV, exhibits enormous sequence variation throughout the range of host species. We sampled 91 feral cats from six disparate locales and studied the phylogenetic relationships of viral DNA from infected cats using both pol and env genes (520 and 684 bp, respectively). The patterns from the two genes recapitulated previously described major FIV clades and showed concordance between phylogenetic patterns of the pol and env genes. Evidence for recombination between the pol and env genes was not found among a sampling of nine isolates, although evidence for intragenic exchange within the env gene was observed in two isolates. A small local population of cats from a rural farm in the United Kingdom had a remarkably high FIV antibody prevalence (47%), but displayed 8-fold less overall diversity of FIV genomic variation compared with FIV from different parts of the world. We interpret this low variation as a consequence of a recent monophyletic introduction of FIV into the population.

Animals↗
PubMed1996

Physiological response of the European hedgehog to predator and nonpredator odour.

A respiratory chamber was used to investigate physiological responses of hedgehogs to predator and nonpredator odour cues, introduced by passing air through different faecal suspensions. Five recently caught hedgehogs showed a significant increase in oxygen consumption (29% +/- 18% at 95% c.i.) when treated with badger (predator) faecal suspension, and 10 hedgehogs held in captivity for ca. 2 years showed no significant response. The responses of recently caught hedgehogs to odour from badger (predator) and roe deer (non-predator) faecal suspensions were then investigated, over a range of concentrations spanning 3 orders of magnitude. Five hedgehogs were tested with badger odour; of these, 3 were also tested with roe deer odour. The mean rise in oxygen consumption was significantly greater in response to badger than to roe deer faecal suspension, but there was no significant variation in strength of response over the range of concentrations tested, and increased oxygen consumption was not associated with any increase in levels of visible activity. The responses are interpreted as an increase in arousal in response to a potential predatory threat. Lack of response in the captive-held animals raises questions about the welfare of such animals following release. Energy costs and foraging inefficiency associated with arousal may be significant factors of foraging decisions involving predation risk, but more naturalistic measurements would be required for any quantitative analysis.

Animals↗
PubMed1994

Effect of Toxoplasma gondii upon neophobic behaviour in wild brown rats, Rattus norvegicus.

The effect of Toxoplasma gondii on neophobic behaviour (the avoidance of novel stimuli) was assessed in four groups of wild rats with naturally occurring Toxoplasma infection. Two groups were placed in individual cages and tested in a series of experiments which examined the effect of Toxoplasma on the rat's reaction to 3 food-related novel stimuli (odour, food-container, food). A trappability study was performed on the other two groups to test whether Toxoplasma had an effect on probability of capture. The results show that low neophobia was significantly associated with positive Toxoplasma titres in 3 out of 4 groups. We suggest that differences between infected and uninfected wild rats arise from pathological changes caused by Toxoplasma cysts in the brains of infected rats. Such behavioural changes may be selectively advantageous for the parasite as they may render Toxoplasma-infected rats more susceptible to predation by domestic cats (the definitive host of Toxoplasma) and, as a side-effect, more susceptible to trapping and poisoning during post control programmes.

Analysis of Variance↗
PubMed1993

Female multiple mating behaviour in the common shrew as a strategy to reduce inbreeding.

Three hypotheses concerning potential genetic benefits of female multiple mating behaviour are evaluated for the common shrew. In a high-density population, many successful copulations took place between individuals estimated to be close relatives (e.g. full or half siblings). Juveniles resulting from such matings tended to be relatively small at weaning, and were generally less likely to survive to sexual maturity than more outbred individuals. Multiple paternity was discovered in eight of nine litters examined. The incidence of matings between close relatives, the cost of inbreeding, and the high incidence of multiple paternity presented are each consistent with the hypothesis that female multiple mating is a strategy to reduce inbreeding. That is, if females cannot always distinguish close kin, then they may copulate with several different males and so reduce the risk that all their offspring will be sired by a close relative.

Animals↗
PubMed1993

Enzyme defects in glutamate-requiring strains of Schizosaccharomyces pombe.

Among the glutamate-requiring strains of Schizosaccharomyces pombe previously described [1], glu2 and glu3 strains were both shown to lack NAD-specific isocitrate dehydrogenase. glu4 strains were shown to lack glutamine:2-oxoglutarate aminotransferase (GOGAT), and to be defective in ammonia assimilation. The regulation of GOGAT activity in wild-type cells was investigated and was consistent with GOGAT and glutamine synthetase being involved in ammonium assimilation, particularly under conditions of nitrogen limitation.

Gene Expression Regulation, Enzymologic↗
PubMed1993

Rabies and wildlife: a conservation problem?

Understanding the behavioural ecology of wild mammals in rabies epizootics is a prerequisite to scientifically sound management of the disease. The principal vectors of wildlife rabies in a region tend to be abundant representatives of the Carnivora. Although the population dynamics of these species may be radically affected by rabies, and by attempts to control it, they are generally not threatened with widespread extinction as a result. However, the cases of the Blanford's fox, Vulpes cana, the Ethiopian wolf, Canis simensis, and the African wild dog, Lycaon pictus, illustrate how rabies and its control can pose grave conservation problems for rare carnivores. Disease monitoring is therefore an important element of recovery plans for rare species which are potential victims of rabies and other epizootic pathogens, and the benefits and disbenefits of prophylactic vaccination merit serious evaluation.

Africa↗
PubMed1987

Obstetric outcome in first-time mothers aged 40 years and over.

This retrospective study examines the outcome of pregnancy after 28 weeks gestation in 100 consecutive, unselected primiparae who were aged 40 years or more. Antenatally, the incidence of hypertension was increased. There was an increased incidence of induction of labour and caesarean section. There were no maternal deaths and no evidence of an increase in maternal morbidity. After correction for congenital malformations, the perinatal mortality rate was not increased in these mothers. The incidence of Down's Syndrome was 4%, as expected. In general, the outcome of the pregnancy for the mother and her baby was satisfactory. Contrary to popular opinion, the results justify an optimistic approach to women about to become mothers for the first time in their forties, and the traditional high intervention rates may not be justified.

Adult↗
PubMed1987

Induction of labour, birthweight and perinatal mortality by day of the week.

There were 66,974 births at the three largest Dublin maternity hospitals in the years 1980-1982. Data on numbers of spontaneous and elective births, birthweight and perinatal mortality were analysed by day of the week. Perinatal mortality rates were highest on Wednesdays and Saturdays. The rate on Sunday was close to average. The largest number of perinatal deaths per day occurred on Wednesdays and the smallest on Sundays. Significant variations in mortality rates and percentage low birthweight were found among the 19% of infants who were born electively, but not among those born after a spontaneous onset of labour. High-risk pregnancies, including many with intra-uterine fetal death, were induced in large numbers from Tuesdays through Saturdays with a peak on Wednesdays. Low risk cases were induced mainly from Monday through Fridays with a peak on Fridays. The pattern of perinatal mortality through the week followed closely that of the risk status of pregnancies delivered electively. The results indicate that the pattern of perinatal mortality by day of the week of birth was determined by a highly organized weekly routine of selective elective delivery.

Birth Weight↗
PubMed1986

Behaviour of recombinant plasmids in Aspergillus nidulans: structure and stability.

A pyrG- Aspergillus strain was transformed with plasmid pDJB-1, derived from pBR325 by insertion of the Neurospora crassa pyr4 gene (orotidine 5'-phosphate carboxylase), giving mitotically unstable transformants. Aspergillus DNA which acted as an "autonomously replicating sequence" (ARS) in yeast was inserted into pDJB-1 and the resulting construct, pDJB12.1, gave mitotically stable transformants when introduced into Aspergillus. Transformants obtained with pDJB-1 and pDJB12.1 gave few pyr- progeny in crosses to a pyrG+ strain. Southern hybridisation analysis of pyr+ transformants obtained with pDJB-1 revealed restriction fragments expected for integrated plasmid but transformants obtained with pDJB12-1 showed only bands derived from free plasmid. pDJB-1 and derivatives of pDJB12.1 could be recovered from transformants. These derivatives could not be explained by straightforward excision of integrated pDJB12.1 sequences but could result from recombination between plasmid molecules. Hybridisation of undigested transformant DNAs showed that the transforming DNA was present in a high molecular weight form. These results suggest: (1) pDJB12.1 derivatives and possibly pDJB-1 can replicate autonomously in Aspergillus; (2) A. nidulans DNA acting as an ARS in yeast enhances replication and/or segregation of transforming plasmids in Aspergillus; and (3) recombinant plasmids may undergo rearrangements when introduced into Aspergillus.

Aspergillus nidulans↗
PubMed1983

Pregnancy in the diabetic patient: timing and mode of delivery.

The clinical outcome of 141 consecutive diabetic pregnancies managed in the National Maternity Hospital between January 1, 1979, and October 31, 1982, is described. Patients with gestational diabetes were excluded. There were 12 spontaneous abortions, and the perinatal mortality in 129 viable pregnancies was 31/1000. The malformation rate was 6.4%. Significant perinatal morbidity occurred in 20% of infants. The incidence of cesarean section was 20%. Spontaneous labor after 38 weeks occurred in 30% because there was a deliberate policy to allow all uncomplicated pregnancies to continue to term. This policy had benefits for the infant as well as the mother because there was a notable reduction in neonatal morbidity. Possible explanations of high cesarean section rates in other centers are discussed.

Birth Weight↗