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J Finlayson

Publications and source records attributed to J Finlayson.

At least 37 records · Page 2Linked to original sources
PubMed1987

Dopamine affects angiotensin II-induced steroidogenesis by altering clearance of the peptide in man.

Infusion of dopamine is reported to reduce the response of aldosterone to infused angiotensin II in sodium-deplete but not sodium-replete man. Six normal male subjects were infused with angiotensin II in graded doses (2, 4 and 8 ng/kg per min) with or without dopamine (1.0 microgram/kg per min) during both dietary sodium repletion and depletion. The responses of both aldosterone and 18-hydroxycorticosterone to infusion of angiotensin II appeared to be reduced by dopamine in sodium-deplete, but not sodium-replete, subjects. However, when the relationships between plasma concentrations of angiotensin II and corticosteroid were examined it was evident that plasma concentrations of angiotensin II were lower when dopamine was infused concurrently with the peptide (P less than 0.05). In a second study, six sodium-deplete males were infused with angiotensin II at a constant rate (6 ng/kg per min) while dopamine (or placebo) was given in graded doses (0.5, 1 and 5 micrograms/kg per min). Renal plasma flow was estimated from total body clearance of para-aminohippuric acid. Overall, angiotensin II concentrations were lower during dopamine infusion compared with those during infusion of placebo (63.2 +/- 9.7 (S.E.M.) vs 92.3 +/- 6.4 pmol/l; P less than 0.01) and this was associated with a 40% increase in effective renal plasma flow (627 +/- 68 vs 451 +/- 15 ml/min; P less than 0.05); there again appeared to be a reduced aldosterone response during combined angiotensin II/dopamine infusion compared with that during infusion of angiotensin II alone (1003 +/- 404 vs 1225 +/- 146 pmol/l; 0.05 less than P less than 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

18-Hydroxycorticosterone↗
PubMed1986

Experimental infection of pregnant sheep with Toxoplasma gondii: pathological and immunological observations on the placenta and foetus.

The pathogenesis of Toxoplasma gondii infection in pregnant sheep was investigated. In one experiment, sheep were infected at 40, 60 and 90 days gestation and examined 30 days later, while in a second experiment, pregnant sheep were infected at either 60 or 90 days gestation and examined 10, 15 and 20 days later. By 10 days post infection (dpi), the parasite had invaded the gravid uterus and caused focal damage in the caruncular septa and, by 15 days, the degenerative changes had spread to the crypt wall and trophoblast. At this time, toxoplasma were isolated from all challenged foetuses. Foetuses did not produce any significant immune response until 20 dpi when increased numbers of IgM positive cells were found in lymphoid tissues. However, at 30 dpi, the numbers were normal while numbers of IgG positive cells and circulating IgG were increased. It was concluded that, while the foetal immune system need not be fully mature to respond to T. gondii infection, its ability to mount a response is limited at 70 days gestation but becomes increasingly competent after this. Furthermore, while it is able to respond more comprehensively with increasing maturity, maturation itself appears to be accelerated by the stimulus of infection.

Animals↗
PubMed1986

Malignant catarrhal fever: experimental transmission of the 'sheep-associated' form of the disease from cattle and deer to cattle, deer, rabbits and hamsters.

Attempts to transmit malignant catarrhal fever (MCF) from 16 bovine cases of the 'sheep-associated' form of the disease are described. On two occasions disease was transmitted to bovine calves but transmission to red deer (Cervus elaphus) was not achieved. In addition, MCF was transmitted from one experimentally affected calf to a rabbit and on another occasion directly to rabbits with material from a field case which failed to transmit to a bovine calf or red deer. Subsequently each of these isolates was readily passaged through rabbits and one was also passaged to Syrian hamsters. Tissue from MCF-affected red deer consistently produced disease on inoculation into rabbits and deer but failed to cause disease in bovine calves. Contact infection between red deer occurred once and roe deer (Capreolus capreolus) were also shown to be susceptible to infection by inoculation. Passage of MCF in rabbits with an isolate from red deer failed to produce evidence of further adaptation even after 125 serial passages. Despite the failure to transmit disease from cattle to deer or from deer to cattle it is considered probable that there is only one sheep-associated agent which causes MCF in both species. The reasons for the anomalies in transmission of this form of the disease are discussed.

Animals↗
PubMed1985

Acute placentitis and spontaneous abortion caused by chlamydia psittaci of sheep origin: a histological and ultrastructural study.

A sheep farmer's wife who had been assisting with lambing developed an influenza like illness in the 28th week of pregnancy. After five days of malaise she spontaneously delivered a stillborn infant; she became acutely ill during the immediate postpartum period with septicaemic shock, acute renal failure, and disseminated intravascular coagulation. The diagnosis was made by isolation and identification of Chlamydia psittaci from the placenta, fetal heart blood, and fetal lung, together with maternal serological evidence. The prominent histological and ultrastructural appearances of the chlamydial placentitis are described.

Abortion, Spontaneous↗
PubMed1985

Transmission of a malignant catarrhal fever-like syndrome to sheep: preliminary experiments.

The transmission of a malignant catarrhal fever-like syndrome to sheep is reported. Fetal sheep between 40 and 66 days gestation were inoculated intravenously with viable cells either from a red deer with clinical malignant catarrhal fever or from rabbits with the disease. Of the 21 fetuses in the experiment only five were born live and of these four developed clinical signs similar to malignant catarrhal fever in other species and died or were killed 10, 16, 47 and 175 days after birth. The fifth lamb remained unaffected. Histology of the four affected lambs revealed a generalised lymphoproliferation, with T-dependent areas of lymphoid tissues being affected, and an overall paucity of immunoglobulin containing cells. In addition arteritis and interstitial infiltration of many organs by lymphoid cells was present. The infectious agent was not reisolated in rabbits from lambs or passed to red deer housed in the same pen and it is thus considered possible that gene expression of the putative virus was incomplete.

Animals↗
PubMed1984

Malignant catarrhal fever.

Malignant catarrhal fever is briefly reviewed and recent findings are described. Initially the disease was observed as a disease of cattle in Europe where, although no cause could be identified, circumstantial evidence implicated sheep as a source of infection and it was thus designated 'sheep-associated' malignant catarrhal fever. Subsequently the disease was observed in Africa where it became evident that a herpesvirus which normally infects wildebeest was the cause. It is now apparent that deer are highly susceptible to both forms of the disease, the sheep-associated form being a serious problem in farmed deer. The wide spectrum of clinical and pathological changes that occur in affected deer are described. A major constraint to studies of sheep-associated malignant catarrhal fever has been the absence of an experimental laboratory system. However, from affected deer it has been possible to transmit the disease to rabbits and thus has allowed detailed pathogenesis studies to be made which are summarised in this paper. It is suggested that the agent of sheep-associated malignant catarrhal fever is a virus and that when a particular subpopulation of T-lymphocytes is infected a profound immunological perturbation results; the lesions of malignant catarrhal fever being explained by a benign T-lymphocyte hyperplasia accompanied by a deregulation of cytotoxic natural killer lymphocytes that gives rise to tissue necrosis.

Animals↗
PubMed1984

Transmission of louping-ill virus in goat milk.

The course of louping-ill virus infection was examined in lactating goats. Seven goats were inoculated subcutaneously and titres of virus in blood and milk were monitored. All goats became viraemic with maximum titres of between 10(1.6) and 10(4.0) plaque forming units (pfu)/0.2 ml. Virus was also detected in the milk of all goats at maximum titres of between 10(0.6) and 10(5.7) pfu/0.2 ml. Only one of these goats exhibited clinical signs which were transient. In contrast, five of the 13 kids sucking these goats became infected and all showed marked clinical signs and one died and two were killed in extremis. It is considered that goats do not represent an efficient maintenance host for louping-ill virus but the excretion of virus in milk could represent a public health hazard.

Animals↗
PubMed1984

Pathogenesis of 'sheep-associated' malignant catarrhal fever in rabbits.

Pathogenesis studies of experimentally produced sheep-associated malignant catarrhal fever (MCF) in laboratory rabbits are described. Animals were examined at intervals after inoculation. The principal change was a proliferation of lymphoid cells which began as soon as three days and became quite pronounced by 13 days after inoculation. The appendix, mesenteric lymph node and spleen were most obviously affected. The reason for this was a progressive increase in T-lymphocytes, which appeared to be a hyperplasia rather than neoplasia in T-dependent areas of these organs. Lymphoid cells also accumulated in interstitial spaces of non-lymphoid organs. The use of cyclosporin-A suppressed the lymphoid proliferation but rabbits still developed clinical MCF after a similar incubation period. It is suggested that the agent of MCF might produce its effect by infecting and causing a dysfunction of lymphoregulatory cells, resulting in benign polyclonal T-lymphocyte proliferation. Terminal necrosis could be due to natural killer cell activity.

Animals↗
PubMed1983

A cytotoxic T-lymphocyte line propagated from a rabbit infected with sheep associated malignant catarrhal fever.

The propagation of a cell line from a rabbit affected with the sheep associated form of malignant catarrhal fever is described. Immunological and morphological characteristics of the cell indicated that it was a T-lymphocyte and the presence of electron dense cytoplasmic granules suggested that the cell could be further classified as a large granular lymphocyte. The cell line required a feeder layer and was cytotoxic to both primary cell cultures and cell lines, a characteristic of large granular lymphocytes. No evidence of the nature of the agent could be detected but as few as 10(2) cells transmitted the disease. These findings are discussed and the possibility that infection and subsequent dysfunction of large granular lymphocytes may have a central role in the pathogenesis of malignant catarrhal fever is considered. That cells with similar characteristics have been derived from Herpesvirus saimiri and H ateles infected marmoset lymphocytes suggests that the lymphoproliferation associated with infection by these two simian herpes-viruses and malignant catarrhal fever may have a similar pathogenesis.

Animals↗
PubMed1982

Carcinoid heart disease: diagnosis by two-dimensional echocardiography.

We prospectively studied 14 patients with the carcinoid syndrome to determine if two-dimensional echocardiography could detect the nature and extent of valvular abnormalities. Eight of the 14 patients had definite abnormalities of the right-sided cardiac valves. The tricuspid valve had a characteristic appearance, similar to previously described pathologic findings. The leaflets appeared diffusely thickened, shortened and stiff without evidence of commissural fusion. Saline contrast studies demonstrated tricuspid regurgitation, which corresponded to the severity of the tricuspid valve involvement. The pulmonary valve could only be adequately assessed in seven of 14 patients, and morphologic abnormalities similar to those in the tricuspid valve were found. Follow-up studies have shown progression of cardiac disease in six of eight patients. We conclude that two-dimensional echocardiography can detect the characteristic cardiac abnormalities in the carcinoid syndrome and may be a useful tool for following their progression.

Adult↗
PubMed1981

Immunosuppression in toxoplasmosis: studies in sheep with vaccines for chlamydial abortion and louping-ill virus.

Toxoplasma gondii infection was established in sheep seven days (acute infection) or 28 days (chronic infection) before they were given enzootic abortion (EAE) vaccine alone or simultaneously with louping-ill (LI) vaccine. Uninfected controls received the same vaccination schedule. The serological response of acute toxoplasma-infected sheep to initial LI vaccination was significantly depressed but after revaccination four weeks later these sheep demonstrated a response equal to that of the revaccinated controls. Infected sheep also gave a significantly poorer response to EAE vaccine than control animals, the effect being more marked in those with chronic infection. Revaccination evoked no clear response in any group but on three of five sampling days antibody titres of controls were significantly higher than those of infected sheep.

Animals↗
PubMed1981

Toxoplasma gondii: its effect on the ovine popliteal lymph node.

Four non-immune sheep and two with naturally acquired antibody were inoculated subcutaneously in the lower part of the leg with 100 cysts of Toxoplasma gondii. Two other non-immune sheep were given a control inoculum. Efferent lymph from the popliteal nodes on the side of the injection was collected via a cannula and injected into mice. Live toxoplasms were present in the lymph of non-immune sheep from day 2 until day 15, at which time the experiment was terminated. Corresponding samples of lymph from the one immune animal tested were almost always negative. Severe pathological changes were present in lymph nodes from non-immune sheep. Gross enlargement, loss of architecture, haemorrhages, and some necrosis occurred, and the sinuses were packed with plasma cells and plasmablasts. Changes in the nodes of immune sheep were similar but less striking, with retention of architecture, no haemorrhages and no necrosis. It was concluded that the lymphadenopathy in sheep is similar to that in rabbits, mice and man with toxoplasmosis.

Animals↗