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Biomedical subjects

L Morrison

Publications and source records attributed to L Morrison.

At least 37 records · Page 2Linked to original sources
PubMed1988

Expression of class II MHC gene products by macrophages in human uteroplacental tissue.

The expression of class II MHC determinants by fetal and maternal macrophages in human uteroplacental tissues was examined with monoclonal antibodies directed against HLA-DR, DP and DQ antigens. Maternal macrophages in early and full-term pregnancy decidua were HLA-DR positive, and a substantial proportion also expressed DP and DQ antigens. Fetal macrophages in chorionic villous stroma in first-trimester pregnancy were rarely HLA-DR positive, and DQ and DP antigens were never expressed. In term placental tissues, groups of villous stromal macrophages were HLA-DR positive, as were fetal macrophages within amniotic mesenchyme. In contrast, DP and DQ antigens were detected on a small minority of fetal macrophages in term placental tissues. DP and DQ antigens were not detected in the absence of DR antigens.

Chorionic Villi↗
PubMed1987

Modulation of monocyte complement synthesis by interferons.

Recombinant Escherichia coli-derived gamma-interferon has been shown to stimulate synthesis of the second component of complement (C2), factor B and C1 inhibitor, but to inhibit synthesis of the third component (C3). alpha- and beta-interferons stimulate synthesis of factor B and C3 inhibitor, inhibit C5 synthesis but do not alter synthesis of C2. alpha- and beta-interferons act synergistically with gamma-interferon to enhance both factor B and C1-inhibitor synthesis.

Cells, Cultured↗
PubMed1987

Phase change enzyme immunoassay.

A novel enzyme-linked immunoassay employing a partitioning chromophore was developed. The assay system consisted of an aqueous phase and an immiscible organic solvent. Antigen-antibody interaction was indicated by transfer of a chromogenic indicator from the aqueous phase to an organic layer. The indicator employed was a water-soluble phosphate ester of phenylazophenol. Hydrolysis of the ester by acid or alkaline phosphatase produced a water-insoluble phenol that partitioned into toluene. The enzyme employed in this assay format can be covalently linked to antibody or a specific antibody for the phosphatase can be used. Phase change immunoassays were developed for the measurement of alkaline phosphatase, human IgG in whole blood, and the human tumor marker prostatic acid phosphatase. Solid supports of small polystyrene latex particles and Sephadex were employed.

Acid Phosphatase↗
PubMed1987

Economics of a dry-cow anthelmintic drenching programme for dairy cows in New Zealand. Part 1. Overall response in 47 herds.

Trials were conducted on 47 seasonal supply dairy farms (greater than 5500 cows) to assess the economics of a dry-cow anthelmintic drenching programme. The programme was administered during the autumn/winter of 1983 and consisted of two treatments, the first shortly after drying off (late April-early June) and the second shortly before calving (mid-July-late August). The effects of the programme on the body condition of cows over winter and their subsequent milk production and reproductive performance were assessed. Overall, the treatment did not result in a worthwhile improvement in cow condition over winter. However, there was a small, but significant overall increase in milk production (2.24 kg milkfat/cow/lactation = 51.5 l milk; P less than 0.01). Young cows (3 years old) did not respond significantly better than mature cows, but high quality cows (as assessed on the basis of the previous season's milk production) responded significantly better than those of poorer quality. The pre-calving condition of cows did not significantly influence the magnitude of their response. Calving data for the year following the trials indicated that conception rates and time of conception were unaffected by the drench programme. At prices prevailing at the time of the trials, the programme proved to be only marginally economic overall (approximately 1 kg milkfat/cow was required simply to cover the cost of the anthelmintic used). However, levels of response in the individual herds involved varied considerably.

Animals↗
PubMed1987

Economics of a dry-cow anthelmintic drenching programme for dairy cows in New Zealand. Part 2. Influence of management factors and other herd characteristics on the level of response.

The results of a series of trials conducted on 47 seasonal supply dairy farms in the southern North Island of New Zealand, which indicated a statistically significant overall production response of 2.24 kg milkfat/cow/lactation following a 2-treatment dry-cow anthelmintic drenching programme (Bisset et al., 1987), were subjected to further analyses in an attempt to identify any management factors or herd characteristics which may have influenced the levels of production response to treatment in individual herds. The management factors examined included calf drenching practices, types of grazing system, mean pre-calving condition of the herds, and 'nutritional status' of the herds over the milking season. The influence of herd quality, herd size and geographical location were also examined. Considered separately, only calf drenching practice had a significant influence on the level of herd response to treatment. Increases in milkfat production/cow due to the treatment programme were significantly greater (P less than 0.05, t-test) on farms where calves had received a minimal number of drench treatments (less than or equal to 2) between weaning and the end of March (mid-autumn) (+5.32 kg/cow/lactation, P less than 0.01) (= 108.2 l milk), than on farms where calves had received regular 3-4 weekly treatments over the same period (+0.42 kg/cow/lactation, N.S.) While none of the other factors, considered in isolation, appeared to significantly influence the production response of herds, observations on possible interactive effects suggested that the grazing system employed was probably of importance in so far as it determined the level of exposure of cows to calf-contaminated pasture. Thus, the greatest mean response to the treatment programme occurred in herds where cows were overwintered on areas grazed during the milking season by calves which had received less than or equal to 2 drench treatments from weaning until the end of March (+5.95 kg milkfat/cow/lactation, P less than 0.01).

Analysis of Variance↗
PubMed1987

Differences in gonadotrophin concentrations and pituitary responsiveness to GnRH between Booroola ewes which were homozygous (FF), heterozygous (F+) and non-carriers (++) of a major gene influencing their ovulation rate.

The mean plasma concentrations of FSH and LH were significantly higher in FF ewes than in ++ ewes with those F+ animals being consistently in between. These gene-specific differences were found during anoestrus, the luteal phase and during a cloprostenol-induced follicular phase, suggesting that the ovaries of ewes with the F-gene are more often exposed to elevated concentrations of FSH and LH than are the ovaries of ewes without the gene. The gene-specific differences in LH secretion arose because the mean LH amplitudes were 2-3 times greater in FF compared to ++ ewes with the LH amplitudes for F+ ewes being in between. The LH pulse frequencies were similar. In these studies the pulsatile nature of FSH secretion was not defined. The pituitary contents of LH during the luteal phase, were similar in all genotypes whereas for FSH they were significantly higher in the F-gene carriers compared to ++ ewes. The pituitary sensitivity to exogenous GnRH (0.1, 0.5 and 25 micrograms i.v.) was related to genotype. Overall the LH responses to GnRH were lower in FF ewes than in ++ ewes with the results for the F+ ewes being in between. The FSH responses to all GnRH doses in the FF genotype were minimal (i.e. less than 2-fold). In the other genotypes a greater than 2-fold response was noted only at the highest GnRH dose (i.e. 25 micrograms). Treatment of FF and F+ but not ++ ewes with GnRH eventually led to a reduced FSH output, suggesting that the pituitary responses to endogenous GnRH were being down-regulated in the F-gene carriers whereas this was not the case in the non-carriers. Collectively these data confirm that peripheral plasma and the pituitary together with the ovary are compartments in which F-gene differences can be observed. In conclusion, these findings raise the possibility that F-gene-specific differences may also extend to the hypothalamus and/or other regions of the brain.

Animals↗
PubMed1986

What stresses health professionals? A coding system for their answers.

The reliabilities of a coding system derived from open-ended descriptions of stresses and of satisfactions within the medical role are reported as acceptable. The method is considered useful where defences may be raised by direct questioning, and at times of transition where questionnaires derived from previous literature may miss new sources of stress.

Career Choice↗
PubMed1986

Synthesis of complement components (C3, C2, B and C1-inhibitor) and lysozyme by human monocytes and macrophages.

The synthesis of C3, C2, factor B (B) C1-inhibitor and lysozyme has been studied in monocytes and macrophages isolated from the synovial fluids of patients with rheumatoid arthritis. Concentrations of all 5 proteins in culture supernatants were measured by the sandwich ELISA technique. Kinetic studies showed that only lysozyme and C3 could be detected in monocyte culture supernatants on the first day of culture, whereas C2, B and C1-inhibitor were not present until the third day. In contrast all 5 proteins could be detected in the supernatants of macrophage cultures on day 1. In both monocyte and macrophage cultures synthesis of lysozyme and C1-inhibitor continued throughout the culture period, whereas synthesis of C2, B and C3 appeared to be reduced after the fifth day in culture. Quantitative studies showed that the secretion rates of lysozyme (4,700 X 10(3) molecules/cell/hr) was similar in monocytes and macrophages. Synthesis rates for all 4 complement components in monocyte cultures were less than 0.2% of that for lysozyme. Although the synthetic rates were higher in macrophages, even then they constituted less than 2% of the rate for lysozyme. Synthetic rates for complement components, but not lysozyme, were increased by BSA-anti-BSA antigen-antibody complexes and reduced by serum-treated complexes. Although the functional activity of monocyte B was similar to that for serum, the activity of monocyte C2 was 5 times that of serum C2. As C42 formed with monocyte C2 had a half-life of 13.5 min at 30 degrees C, compared with 4.5 min for the enzyme formed with serum C2, it is probable that monocyte C2 is oxidized by the oxygen products of these cells.

Antigen-Antibody Complex↗
PubMed1985

Loss of pulsatile luteinising hormone secretion in men with chronic renal failure.

In an attempt to determine the nature of hypothalamic and pituitary dysfunction in renal failure the secretory patterns of luteinising hormone were measured in men with end stage renal disease and compared with those in healthy controls and renal transplant recipients of similar age distribution. Mean luteinising hormone and oestradiol concentrations were significantly higher and the number of luteinising hormone secretory pulses was significantly lower in uraemic men compared with controls. Plasma testosterone and oestradiol concentrations were significantly lower in renal transplant recipients than normal men, but there were no significant differences in mean gonadotropin concentrations or the number of pulses of luteinising hormone between the two groups. As pulses of luteinising hormone are thought to reflect episodic gonadotropin releasing hormone from the hypothalamus these data suggest that uraemia interferes with central mechanisms controlling synchronised release of gonadotropin releasing hormone. This defect appears to be reversible after successful transplantation.

Adult↗
PubMed1985

Biosynthesis of complement components by cultured rat hepatocytes.

Hepatocytes which had been isolated from the livers of Charles River rats were cultured in vitro. The cells were shown to synthesize albumin and the complement components C4, C2, C3 and B. Pulse-label studies with [35S]methionine showed that C4 and C3 were synthesized as single polypeptide chains. Pro-C4 did not appear to be converted into the plasma form of C4 intracellularly, whereas cell lysates contained the alpha- and beta-chains of plasma C3 as well as pro-C3. It is concluded that culture of rat hepatocytes in vitro provides a useful technique for studies of the synthesis of complement components.

Albumins↗
PubMed1985

The influence of captopril, the nitrates and propranolol on apparent liver blood flow.

Indocyanine green estimated apparent liver blood flow was measured in normal volunteers following glyceryl trinitrate, propranolol, isosorbide mononitrate and captopril. Glyceryl trinitrate and propranolol significantly reduced apparent liver blood flow. Isosorbide mononitrate did not alter apparent liver blood flow or produce an additional reduction in apparent liver blood flow when combined with propranolol. Captopril did not alter apparent liver blood flow despite a significant fall in mean arterial pressure and rise in plasma renin activity. Captopril and isosorbide mononitrate if shown to reduce portal pressure, do so without a fall in apparent liver blood flow.

Adult↗
PubMed1985

Assessment of immunological techniques in the diagnosis and prognosis of ocular malignant melanoma.

Tests of cell mediated immunity (one and two stage leucocyte migration inhibition assays) and humoural immunity (membrane immunofluorescence and serum effects on leucocyte migration) were done with leucocytes and sera from 36 patients with uveal melanoma, five with conjunctival melanoma, 21 with non-malignant ocular disease, and 189 with cutaneous melanoma. Cell mediated reactivity with melanoma extracts and serum reactivity with cultured melanoma cells were significantly more frequent in the melanoma patients, but control donor reactivity was also relatively high. Maximum reactivity was found with cells or serum from those patients in whom, on pathological examination, the intraocular melanoma had penetrated the sclera and in patients with conjunctival melanoma. Maximum separation of melanoma patients from control donors was achieved by consideration of the results of several tests done simultaneously. These immunopathological studies were made during the period from 1972 to 1978. At follow-up in 1983 four of the five patients suffering from conjunctival melanoma had died from metastases, and 10 of the 36 with uveal melanoma had died from metastatic disease. The immunological reactions, while of some value in separating melanoma patients from those without melanoma, did not predict whether a particular patient with uveal melanoma would die of metastatic disease or would survive.

Antibody Formation↗
PubMed1984

Herpes simplex virus type-2 glycoprotein-subunit vaccine: tolerance and humoral and cellular responses in humans.

Twenty-three subjects were administered three doses of inactivated herpes simplex virus (HSV) type 2 (HSV-2) glycoprotein-subunit vaccine, with doses 2 and 3 being given four and 22 weeks after dose 1. Both HSV-neutralizing antibody and antibody effective in antibody-dependent cell-mediated cytotoxicity were detected in serum samples of 12 of the 13 initially seronegative subjects by week 8. The geometric mean titers of both antibody types decreased between weeks 8 and 22 but increased one week after dose 3. HSV-neutralizing antibody remained detectable in serum samples of seven of the 10 initially seronegative subjects assayed seven months after dose 3. Cell-mediated immunity was detected by lymphocyte transformation responses to HSV-2 after vaccine administration in 12 of the 13 initially seronegative subjects. Unlike humoral antibody, which waned over time, in vitro cell-mediated immune responses remained stable over the seven-month follow-up period after dose 3. This HSV-2-subunit vaccine is well tolerated and elicits both humoral and cell-mediated immune responses to HSV.

Adult↗
PubMed1984

Some aspects of thecal and granulosa cell function during follicular development in the bovine ovary.

The patterns of ovarian follicular development and the steroidogenic properties of individual follicles (greater than or equal to 2 mm diam.) were assessed in Angus cows from Day - 5 until Day + 1 of the oestrous cycle (oestrus = Day 0). Individual follicles were judged to be healthy or atretic using a new classification system incorporating assessments of thecal vascularity and colour, the number of granulosa cells, the presence or absence of debris in follicular fluid and the status of the oocyte. The results suggest that the theca interna of small antral follicles (less than 5 mm diam.) responds to LH and synthesizes androstenedione before the granulosa cells develop an appreciable ability to metabolize androgen to oestrogen. Regardless of follicle size, the output of thecal androstenedione per unit mass of tissue remained unchanged in healthy but not in atretic follicles. On a per cell basis, aromatase activity increased in granulosa cells from healthy but not from atretic follicles with increasing follicle size. Peak levels of aromatizing activity were consistently observed in dominant oestrogen-enriched follicles on Day 0 although similar activity was also observed in some healthy follicles (greater than or equal to 8 mm diam.) on other days of the cycle. Early atresia in bovine follicles was characterized by an absence or lowering of aromatase activity in granulosa cells which always preceded any reduction in the thecal steroidogenic response to LH. It was estimated that between 20 and 60 antral follicles (greater than or equal to 2 mm diam.) per cow may respond to LH by synthesizing androgen whereas only 1-3 follicles (greater than 5 mm diam.) have granulosa cells capable of metabolizing androstenedione or testosterone to oestradiol.

Androstenedione↗