Search PubMed⌕ Search

Biomedical subjects

R E Oliver

Publications and source records attributed to R E Oliver.

At least 37 records · Page 2Linked to original sources

Changes in blood coagulation parameters of red deer (Cervus elaphus) experimentally infected with malignant catarrhal fever.

Changes in blood coagulation parameters were followed in four red deer (Cervus elaphus) experimentally infected with malignant catarrhal fever (MCF) of deer. Blood platelet counts, activated partial thromboplastin time (APTT), one-stage prothrombin time (OSPT), activated clotting time (ACT), plasma anti-thrombin III (ATIII) activity, fibrinogen degradation production (FDP) and fibrinogen levels were measured. Inoculated deer became pyrexic after 17 or 19 days. Thereafter they developed watery diarrhoea which rapidly became haemorrhagic. The course of the clinical disease ranged from four to six days before the animals were killed or died. All inoculated deer developed abnormalities in laboratory parameters of blood coagulation. These varied within and between animals, but the coagulation profiles of all four animals remained abnormal until death. Post-mortem findings included extensive systemic petechiation, severe haemorrhage in the alimentary canal and vasculitis with disseminated thrombosis. Abnormal coagulation parameters included extension of APTT and OSPT, increased FDP, decreased ATIII and platelet counts and increased fibrinogen levels. The increases in fibrinogen were compatible with the acute phase response. The other coagulation abnormalities and haemorrhage and thrombosis were indicative of disseminated intravascular coagulation (DIC) with consumption coagulopathy, ACT remained normal in all deer although final clot quality was considered poor.

Journal Article↗

The development and evaluation of an ELISA for the detection of antibodies to caprine arthritis-encephalitis virus in goat sera.

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of antibodies to caprine arthritis encephalitis virus (CAEV) in goat sera. The system was evaluated using some 1500 sera from flocks of known clinical history. From this data the interpretation limits of the system were determined. The ELISA system was compared with a gel precipitin test using 5800 sera. Of the positive sera, ELISA detected 97.3% and AGPT 61%. Further evaluation was made using 60 sera of known CAEV reactivity from the USA, and results agreed 100%. Indications are that antibody to the envelope glycoprotein gp135 is being detected. The ELISA system is more sensitive than the precipitin test and is presently being used in a CAEV flock accreditation scheme.

Journal Article↗

Global survey of serological evidence of caprine arthritis-encephalitis virus infection.

Using caprine arthritis-encephalitis virus antigen in the agar gel immunodiffusion test, 3729 serum samples from goats in over 112 locations around the world were tested for precipitating antibodies. Over 90 per cent of the 1265 positive samples came from Canada, France, Norway, Switzerland and the USA, all of which had 65 per cent reactors or greater. Fiji, Great Britain, Kenya, Mexico, New Zealand and Peru had fewer than 10 per cent positive samples; the majority of these could be traced to importations of goats from countries where there was a high occurrence of precipitating antibody. Somalia, Sudan and South Africa had no reactors among 306 samples. No reactors were found among 1116 samples from domestic and indigenous goats which were known to have had no contact with imported goats from countries which had a high occurrence.

Africa↗

Experimental transmission of malignant catarrhal fever to red deer (Cervus elaphus).

Malignant catarrhal fever was transmitted from affected to recipient red deer (Cervus elaphus) using blood or lymphoid suspension as inoculum. Incubation periods ranged from 11 to 26 days. The disease was also transmitted using lymphoid suspension stored overnight at 4 degrees C or at -70 degrees C for 8 months. The experimental disease was characterised by fever, depression, anorexia, diarrhoea and dysentry. The course of the disease was approximately 96 hours. Major lesions consisted of acute mesenteric lymphadenitis and acute haemorrhagic typhlitis and colitis. Lesions in the caecum and colon started as multifocal mucosal haemorrhages and progressed rapidly to massive mucosal haemorrhage.

Journal Article↗

Disorders of urinary concentration and dilution.

A new approach to the classification of disorders of urinary concentration and dilution is recommended based on recent studies of how the kidney elaborates a urine of widely varying osmolality. The capacity to concentrate urine depends on ft, the fractional reabsorption of solute delivered to the loop of Henle; fu, the excretion of solute relative to the sum of solute excretion and solute delivery to Henle's loop; fw, the fraction of solute loss by vascular outflow from the medulla relative to that reabsorbed by the loop; and finally, collecting duct response to antidiuretic hormone (ADH). A decrease in ft or in increased fu or fw will diminish urinary concentrating ability, as will resistance of the tubule to ADH. Conversely, urinary dilution depends on the delivery of sodium and water to the ascending limb; NaCl reabsorption by the ascending limb; and the absence of ADH. A decrease in sodium and water delivery to the ascending limb or in NaCl reabsorption by the ascending limb will impair urinary diluting ability, as will the presence of ADH. The consequences of disorders in urinary concentrating and diluting ability vary widely. In an alert patient with an intact thirst center, there may be no consequence; in a patient unable to communicate thirst or whose thirst center is deranged, the results may be catastrophic. Keeping in mind the kidney's few basic requirements for formation of concentrated or dilute urine may help the physician avoid these potentially serious dislocations of water balance.

Absorption↗

Canine parvovirus infections in a colony of dogs.

A serological study of canine parvovirus (CPV) infections in a colony of dogs was conducted over a period of 8 months. Twenty-two of 24 adults samples initially had significant antibody titres to CPV. Nine litters of puppies were bled at fortnightly intervals and the sera tested for antibodies to CPV. Twenty-nine of 35 naturally PV infections observed were subclinical. A puppy in one litter developed vomiting and diarrhoea during the same period as seroconversion to CPV. Four puppies from a further litter developed histologically confirmed myocarditis. Serological testing of this latter litter indicated that the virus infections occurred between 2 weeks prior to and 1 week post whelping, and that clinical disease developed 20-40 days after viral infection. The mean half life of the decline of passively derived immunity to CPV was 8.3 days.

Animals↗

Bovine leukaemia virus infection in New Zealand cattle.

Bovine Leukaemia Virus (BLV) infection in New Zealand cattle was investigated. In a national survey of 5000 sera from 500 herds, BLV antibody was not detected. An additional 1062 sera from 140 herds were tested and 3 sera were positive. In the herd of origin of one of these 3 sera, 22.6% of cattle were serologically positive for BLV. Where cases of bovine lymphosarcoma had been diagnosed, 38 of 39 herds tested were negative for BLV antibody. Within the remaining herd, 36% of cows tested were serologically-positive. BLV was isolated from 2 serologically positive cows in this herd.

Journal Article↗

Isolation of caprine arthritis-encephalitis virus from a goat.

Caprine arthritis-encephalitis-virus (CAEV) was isolated from the carpal joint of an Anglo-Nubian yearling goat with chronic progressive pneumonia and subclinical carpal arthritis. Anti-CAEV antibody was detected in this goat and in nine of 69 goat sera tested from two herds.

Journal Article↗

Urinary concentration in the papillary collecting duct of the rat. Role of the ureter.

Urine was observed to flow intermittently in the collecting ducts of the extrarenal papilla of antidiuretic rats. The purpose of this investigation was to test Reinking and Schmidt-Nielsen's hypothesis that intermittent flow plays an important role in the production of maximally concentrated urine. Samples of collecting duct fluid were obtained from the base and tip of the papilla by micropuncture through the intact ureter. Fluid osmolality rose sharply from base, 894+/-120 mosmol/kg H(2)O(-1) (mean+/-SE), to tip, 1,667+/-114 (P<0.001), a distance of only 2 mm, and was due exclusively to reabsorption of water. After excision of the ureter, which abolished intermittent flow, osmolality fell modestly at the base to 723+/-82 mosmol/kg H(2)O(-1) (P < 0.02), but strikingly at the tip to 1,012+/-103 (P < 0.001). The pelvic ureter was paralyzed by topical verapamil and dimethylsulfoxide, which abolished intermittent flow. Osmolality of urine at the tip was not changed (1,959+/-184 mosmol/kg H(2)O(-1) before, vs. 1,957+/-126 after paralysis). The ureter was severed just beyond the papillary tip, a maneuver which preserved intermittent flow but abolished urinary reflux over the papilla. Urinary osmolality fell from 1,876+/-134 mosmol/kg H(2)O(-1) to 1,284+/-115 (P < 0.005). These findings demonstrate that when the ureter is intact, over half of the increase in urinary osmolality above isotonicity occurs in the terminal one-fourth of the medullary collecting duct and is due exclusively to water reabsorption (no net solute addition). It is the continuity of the ureter, rather than intermittent flow due to ureteral peristalsis, which is essential for the formation of a maximally concentrated urine.

Animals↗

Ovine progressive pneumonia: pathologic and virologic studies on the naturally occurring disease.

Pathologic and virologic studies were conducted on 13 mature ewes with serum precipitin antibodies to progressive pneumonia virus (PPV). Pulmonary lesions of ovine progressive pneumonia were found in 4 sheep, a meningoencephalitis resembling visna in 1 sheep, chronic proliferative carpal arthritis in 2, and massive lymphoid proliferation in the mammary gland in 3. Virus producing cytopathic effect typical of PPV was isolated from the lungs, mediastinal lymph node, spleen, and choroid plexus of 4 sheep and from the carpal synovium of 2 sheep with chronic carpal arthritis. Three viral isolates selected for further study were antigenically related to visna virus by immunofluorescence and immunodiffusion, but these 3 isolates were not neutralized by antisera to reference strains of visna virus. Seemingly, infection of sheep by ovine retroviruses is common in the United States, and these viruses are capable of causing disease in more than 1 organ system.

Animals↗

Ovine progressive pneumonia: experimental intrathoracic, intracerebral, and intra-articular infections.

Three groups of 4 lambs each were experimentally infected with an isolate of progressive pneumonia virus (PPV) by intracerebral, intra-articular, or intrathoracic routes of inoculation. An additional control group was sham-inoculated by all 3 routes with identically prepared, noninfected inoculum. Sheep were killed 12 to 42 days after inoculation. A mild generalized leptomeningitis was found in 2 of the 4 lambs inoculated intracerebrally. A severe, proliferative synovitis with massive infiltration of lymphocytes and plasma cells was found in the 4 lambs inoculated intraarticularly. Germinal center formation was found in the synovial membrane 42 days after inoculation. Appreciable differences in lung morphologic features were not observed among the 4 groups. The PPV was isolated from virus-inoculated sheep from the choroid plexus, synovium, and lungs from inoculated and noninoculated sites. Nine of the 12 virus-inoculated lambs developed serum antibody to PPV, and specific antibodies were found in the synovial fluid of virus-inoculated joints. Virus was not isolated, lesions were not found, and serum antibody was not demonstrated in sham-inoculated sheep.

Animals↗

Diabetes insipidus: a physiologic approach to diagnosis.

Diabetes insipidus can be delineated in the context of the normal physiology of water metabolism. This approach highlights the common pathway taken by the variety of diseases that can progress to an insufficiency of antidiuretic hormone (ADH) and to diabetes insipidus. A simple diagnostic approach uses homeostatic pathways to separate diabetes insipidus from the other polyuric states. New developments in the biochemical alteration of ADH have improved the ability to individualize hormonal replacement and promise better therapy in the near future.

Deamino Arginine Vasopressin↗