Biomedical subjects
C A Morris
Publications and source records attributed to C A Morris.
Influence of oral contraceptives on the presence and persistence of Candida albicans and beta-haemolytic streptococci in the vagina.
Samples of vaginal secretions of ;normal' women were examined over a period of up to two years. Patients with asymptomatic candidiasis on one occasion were more likely to have Candida albicans again when sampled a year later than were women with no yeasts on the first occasion. This principle applied also to beta-haemolytic streptococci of Lancefield's groups B and D. There was no significant difference in the incidence of C. albicans in the first and the final samples collected. The persistence and new infection rates were not significantly higher in patients taking combined oral contraceptives than in other women although the highest incidence occurred in those taking a lynoestrenol/mestranol preparation. There was a significant association of C. albicans with beta-haemolytic streptococci groups B and D. The implication of these findings is discussed.
Advantage of a routine Reiter protein complement-fixation test in the serodiagnosis of syphilis in pregnancy.
One hundred and twenty-seven (0.3%) reactive serological tests for syphilis were obtained by routine examination of sera from 35,912 antenatal patients.Forty-eight (38%) of these reactive sera were associated with reactive fluorescent treponemal antibody and Treponema pallidum immobilization results and these patients were therefore considered to show serological evidence of treponemal infection. Sera from 13 of these 48 patients (27%) gave reactive Reiter protein complement-fixation tests in the absence of detected ;reagin' antibody. Seventy-nine patients showed non-specific biological false positive reactions to the routine tests. Following clinical assessment of these serologically reactive patients, approximately one in 100 immigrant and one in 2,500 non-immigrant pregnant women examined in this series were treated with penicillin; this represented just over half the number of patients with serological evidence of a treponemal infection, a ratio which was similar for immigrant and native born women. Yaws was the likely treponemal infection in the majority of infected immigrants. The significance of the serological results and the advantages of the Reiter protein complement-fixation test are discussed.
The influence of oral contraceptives on the presence and persistence of Candida albicans and beta-haemolytic Streptococci in the vagina.
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Normal vaginal microbiology of women of childbearing age in relation to the use of oral contraceptives and vaginal tampons.
The vaginal microbiology of women attending a family planning clinic was found to be unrelated to the use of oral contraceptives and vaginal tampons. Beta haemolytic streptococci isolated from this ;normal' population were compared with those from 1,104 women attending general practitioners complaining of vaginal discharge. There is a caution regarding the indications for antibiotic therapy. Observations were made on the effects of contamination of vaginal swabs with yeasts and beta-haemolytic streptococci from the vulva. The persistent character of the vaginal flora over a six-month period is described.
Injection site streptococcal abscesses in a clinic using disposable syringes.
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Two fatal cases of septicaemia due to Erysipelothrix insidiosa.
Clinical, pathological, and necropsy findings are recorded from two cases of endocarditis due to Erysipelothrix insidiosa, one in a 53-year-old grocer and the other in a 56-year-old housewife. The possible sources of infection are suggested.
Human cytomegalovirus-induced inhibition of cytotrophoblast invasion in a first trimester extravillous cytotrophoblast cell line.
Human cytomegalovirus (HCMV) is the leading cause of congenital viral infection in the United States and intrauterine transmission of HCMV occurs in approximately 40% of pregnant women with primary HCMV infection. Although HCMV infection during pregnancy clearly may be detrimental to fetal development, its consequences on placentation remain largely unexplored. In this study, the effects of HCMV infection on cytotrophoblast (CTB) invasion were investigated utilizing the first trimester extravillous CTB cell line SGHPL-4. HCMV infection significantly inhibited SGHPL-4 proliferation, epidermal growth factor (EGF)- and hepatocyte growth factor (HGF)-induced migration and invasion, as well as the secretion of matrix metalloproteinase (MMP)-2 and MMP-9. Both HCMV and EGF activated the EGF receptor (EGFR), inducing receptor tyrosine phosphorylation at specific residues. Of interest, EGFR was differentially activated by HCMV, and viral gene transcription was not required for the observed inhibitory effect on CTB invasiveness. These findings demonstrate that HCMV infection impairs CTB differentiation along the invasive pathway and that the differential regulation of EGFR by HCMV may contribute to impaired CTB function. Elucidating the mechanisms by which HCMV impairs placentation may be key in understanding fetal and maternal pathologies associated with intrauterine HCMV infection.
Feasibility and implications of breeding sheep for resilience to nematode challenge.
There are potentially 2 different types of host response which could be targeted when seeking to breed sheep which require minimal frequency of anthelmintic treatment to maintain acceptable health and productivity in the face of nematode challenge. These are "resistance" (the ability to suppress the establishment and/or subsequent development of a parasite infection), and "resilience" (the ability to maintain relatively undepressed production while subjected to parasite challenge). Most studies have concentrated on resistance, and used faecal worm egg count (FEC) as the selection criterion. However, in Romney sheep in New Zealand, it has become apparent that "resistance to infection" does not equate to "disease resistance" in the strict sense. Although genetically low FEC Romney lambs have been shown to have significantly reduced burdens of the most important nematode species, they nevertheless appear to have no significant production advantages over their higher FEC counterparts when all are grazed together under the same larval challenge. Furthermore there is evidence of an unfavourable association between FEC and dagginess (soiling of the breech area) suggesting that some forms of host response to nematode challenge may result in diarrhoea. Our results suggest that the main benefits of selectively breeding for low FEC are likely to be derived indirectly as a result of reduced pasture contamination. This has led us to investigate resilience as a possible alternative breeding option to resistance. Over a period of 3 years approximately 14,000 progeny of 213 different rams were tested for resilience (assessed in terms of drench requirements using an individual "on demand" treatment procedure), as well as growth rate, dag-score, FEC and fleece-weight. Overall the heritabilities of various measures of resilience examined proved to be relatively low (ranging between 0.10 +/- 0.03 and 0.19 +/- 0.04), although estimates varied between flocks and years possibly as a result of differences in the severity of challenge. Nevertheless, results suggested that progeny-test selection for resilience would lead to lambs with higher growth rates and lower dags-scores when left undrenched on infective pasture. In contrast to some Australian results we found no positive association between resilience to mematode challenge and resistance to infection. If the potential benefits of both resistance and resilience are to be captured our results suggest that an index selection procedure will be needed.
Phenotypic markers for selection of nematode-resistant sheep.
Nematode-resistance of an animal can be defined as an enhanced natural ability, relative to its peers, to both prevent establishment of larval nematodes and evict any that do establish. These parameters are not measurable in a practical sense and consequently nematode-resistance has usually been defined in terms of low faecal nematode egg counts (FEC). Studies in New Zealand and Australia have demonstrated that nematode-resistance, as measured by FEC, has a heritability of about 0.3 in Romney and Merino sheep. However as a selection trait FEC has practical limitations and its use may incur production penalties through withholding drench treatment for prolonged periods or from a need for artificial challenge. FEC is influenced by the level and composition of a natural nematode challenge and especially the expression of the immune response. Thus immunological parameters which reflect the underlying genetic resistance could potentially be used as phenotypic markers. Ideally, a useful phenotypic marker would be easy to sample and its assay would be inexpensive and able to be automated, in addition to being strongly correlated with nematode-resistance. Results from several New Zealand trials have indicated that antibody levels (particularly IgG1) to excretory/secretory antigens of L3 nematodes such as Trichostrongylus colubriformis may meet these criteria. Levels of antibody against L3 antigens are also independent of on-farm drenching strategies. Blood eosinophil count has also been considered for use as a selection parameter but a high degree of sample variability reduces its potential. Other immunological parameters associated with nematode-resistance which have potential as phenotypic markers include serum nematode-specific IgE and products of mucosal mast cells such as proteinases. It is likely that as the critical immune responses of sheep to nematodes become more clearly defined, new immunological parameters with potential for use as phenotypic markers will be found. The definition of these immune responses will also assist in the identification and characterization of genetic markers.
A possible dominant white gene in Jersey cattle.
A white heifer ("Snow") was born in 1991 from coloured registered Jersey parents. She produced six calves sired by coloured Jersey bulls: three white bull calves, two white heifer calves, and one coloured bull calf. One of the white bull calves was mated with 40 Hereford x Friesian yearling heifers (white face, predominantly black body with some white patches). The 38 resulting calves included 16 white and 22 coloured calves. Twelve of the 16 white calves were heifers and four were bulls. Red or black spotting was recorded on some white calves. The results are consistent with an autosomal dominant mutant causing the white phenotype. The mutation appears to have arisen spontaneously in Snow, then passing to her white progeny and white grand-progeny. The white individuals varied from entirely white in a few cases, to most having some residual small areas of red or black pigmentation in patterns not typical of other reported white spotting patterns of cattle.
Depression of thymus-and bursa-dependent immune systems chicks with Marek's disease.
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