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Biomedical subjects

L Melville

Publications and source records attributed to L Melville.

18 recordsLinked to original sources
PubMed2006

Synergistic interactions of the antiretroviral protease inhibitors saquinavir and ritonavir with chloroquine and mefloquine against Plasmodium falciparum in vitro.

The antimalarial activity of several antiretroviral protease inhibitor combinations was investigated. Data demonstrate that ritonavir and saquinavir behave synergistically with chloroquine and mefloquine. These data, and interactions with pepstatin-A, E-64, and bestatin, suggest that human immunodeficiency virus protease inhibitors do not target digestive-vacuole plasmepsins.

Animals↗
PubMed2006

Cultured skin fibroblast cells derived from bluetongue virus-inoculated sheep and field-infected cattle are not a source of late and protracted recoverable virus.

A recent hypothesis to explain the recurrence of bluetongue disease after winter seasonal absences of the vector has suggested a role for persistent infection of sheep. This report presents combined independent work from two laboratories investigating the possible recovery of Bluetongue virus (BTV) over a protracted period after infection of both sheep and cattle. Prior to infection with either cell-culture-adapted or non-culture-adapted BTV, sheep were subjected to a preliminary exposure to Culicoides sp. insects, which reportedly facilitates recovery of virus from infected sheep several months post-infection (p.i.). A series of skin biopsies at different intervals p.i. was used to establish skin fibroblast (SF) cultures from which attempts were made to detect virus by isolation and by molecular and immunological methods. Also examined was the effect on virus recovery of additional exposure to Culicoides sp. prior to skin biopsy during the post-inoculation period. A herd of cattle sentinels for surveillance of natural BTV infection in northern Australia was monitored prospectively for seroconversion. Evidence of infection initiated attempted virus recovery by establishing SF cultures. It was found that in both cattle and sheep there was not a protracted period over which BTV could be recovered from SF cultures. The data do not support a general hypothesis that BTV persists in either sheep or cattle.

Animals↗
PubMed2003

The effectiveness of scalp cooling in preventing alopecia for patients receiving epirubicin and docetaxel.

The aim of this study was to establish the effectiveness of scalp cooling in preventing alopecia for patients with breast cancer who received the trial combination chemotherapy of Epirubicin and Docetaxel. Doubt remains about the general effectiveness of scalp cooling in preventing hair loss for patients receiving chemotherapy. There is very little information available about its specific effectiveness with combinations of Taxanes and Anthracycline drugs. Of the 40 patients who received this drug combination, 10 were included in a pilot study whereas the remaining 30 constituted the main study sample. A randomized controlled study was undertaken whereby the intervention group received scalp cooling via gel cool caps and the control group received no specific preventative intervention. Nurses assessed participants' hair loss using a modified version of the WHO scale at seven time points and also recorded hair loss photographically. Two independent experts rated the photographs using the same scale. Patients self-reported in relation to overall hair loss, hair condition, levels of emotional upset, negativity about appearance, hair re-growth and wig use. Significantly greater hair loss was apparent in the control group during most of the treatment period. However, the level of protection afforded by the cool caps was relatively poor with this chemotherapy combination. The marginal benefits of scalp cooling in this context must be clearly explained to patients.

Alopecia↗
PubMed1994

Phylogenetic characterisation of bluetongue viruses from naturally-infected insects, cattle and sheep in Australia.

The polymerase chain reaction was used to detect the presence of bluetongue virus (BTV) in a number of clinical and insect samples collected in the Northern Territory of Australia. Sequence analyses of the amplified BTV genes differentiated endemic Australian and exotic viruses. Two potential exotic BTV were detected as a result of PCR analyses of blood from sentinel animals and of the insect vector, Culicoides wadai. The detection of BTV in C wadai was the first direct demonstration of the presence of BTV in this potential vector. This new technology can significantly reduce the time taken for a diagnosis from a clinical sample and increase the amount of useful information obtained on a BTV isolate by using rapid sequencing techniques. Sequence data were used to differentiate between BTV20 isolated in 1975 and two isolates of the same serotype, isolated in 1992, and indicated that the latter were probably a recent incursion into Australia from Indonesia due to their greater VP3 sequence homology to the BTV9 (Java) than to Australian BTV isolates.

Animals↗
PubMed1994

Disease-husbandry associations in farmed crocodiles in Queensland and the Northern Territory.

To investigate husbandry-disease associations in farmed crocodiles 7 farms in Queensland and the Northern Territory were visited and details of past and present farm design and husbandry practices were recorded. In addition pathological examination of 300 (mostly young) crocodiles was carried out (85 necropsied, one biopsied and 214 examined retrospectively). Mortality rate and occurrence of disease, especially opportunistic infections with bacteria and fungi, were highest during winter months and in farms located at greater latitudes. A difference in the presence and prevalence of disease between the initial establishment phase of Northern Territory crocodile farms (1984-87) and currently (1988-91) was apparent; parasitic infections are now relatively infrequent and bacterial septicaemias and mycoses less common as a result of some provision of artificial heating for juveniles. Gross and microscopic changes observed in visceral and periarticular gout, bacterial hepatitis/septicaemia, deep and superficial mycosis, pentastomiasis and other parasitic infections are described.

Alligators and Crocodiles↗
PubMed1992

A field evaluation of serological and cellular diagnostic tests for bovine tuberculosis.

This paper describes the field evaluation of a serological test and a new in vitro assay for cell-mediated reactivity for the diagnosis of bovine tuberculosis. The use of a Mycobacterium bovis-specific antigen (MPB-70) in an ELISA to test the serological response to tuberculosis infection resulted in a specificity of 96.4% and a sensitivity of 18.1%. The most favourable results were obtained with the interferon gamma (IFN-gamma) assay which had a sensitivity of 81.8% and a specificity of 99.1%. Respective figures for the single intradermal tuberculin test were 68.1% and 96.7%. The use of MPB-70 as the antigen in the IFN-gamma assay reduced the sensitivity of this assay, without producing any useful increase in specificity. The IFN-gamma assay was also demonstrated to be a practical diagnostic test for use with large groups of cattle.

Animals↗
PubMed1991

Salmonella in captive crocodiles (Crocodylus johnstoni and C. porosus).

The prevalence of salmonellas in captive Crocodylus porosus and C. johnstoni was investigated at 2 Northern Territory crocodile farms. Similar proportions of each species at one farm (20.0 and 27.8% for C. porosus and C. johnstoni, respectively) carried salmonellas, but at the other farm there was a significant difference between the 2 species (81.0 and 5.0%, respectively). Procedures for the slaughter of crocodiles and processing of crocodile flesh for human consumption are outlined and discussed from the viewpoint of minimising salmonella contamination. The prevalence of salmonellas on flesh for human consumption (16.0% of carcases) was higher than that reported for beef and mutton, but lower than that for poultry products (Murrell 1986). Serotypes most often isolated from cloacai and faecal swabs were S. cerro, S. singapore, S. enteritidis and S. arizonae. Of the 10 serotypes isolated from processed carcases, S. singapore was most frequently isolated (33.3% of serotypes identified).

Alligators and Crocodiles↗
PubMed1990

Efficiency of inspection procedures for the detection of tuberculous lesions in cattle.

The sensitivity of the abattoir inspection procedure introduced for Australian export beef in 1976 was compared to a detailed necropsy procedure for the detection of tuberculous lesions in cattle. In a sample of cattle that were reactors to the tuberculin test, abattoir inspection failed to detect an estimated 47% of cattle with lesions. The detailed necropsy examination of cattle with lesions of tuberculosis identified 21 sites of infection compared with 13 to 18 in cattle examined by routine meat inspection procedures. Of the lesions detected during detailed necropsy, 15.9% did not involve the thoracic cavity or the medial retropharyngeal lymph nodes. The failure to detect lesions during abattoir inspection has its greatest significance in an animal with a single lesion. If the 245 cattle found with single lesions during detailed necropsy had been examined by abattoir inspection using the 1976 or the 1986 procedures, 0.8 and 8.9%, respectively, of these animals would not have been detected because the diseased tissues would not have been examined. If meat inspection is to provide an effective means of monitoring the level of bovine tuberculosis during the final stages of eradication, a procedure no less sensitive than that introduced in 1976 should be used.

Abattoirs↗
PubMed1989

An ELISA for the detection of anergic tuberculous cattle.

An enzyme-linked immunosorbent assay (ELISA) for bovine antibody to antigens in unheated Mycobacterium bovis culture filtrate was standardised against a reference serum from an experimentally infected cow. Two Northern Territory herds with a total of 561 cattle were tested. All cattle reacting in the caudal fold tuberculin test, those giving strong reactions in the ELISA and those with visible lesions of tuberculosis were subjected to a detailed bacteriological examination. Of the 19 cattle which yielded isolates of M. bovis, only 4 were positive to the tuberculin test. Serum samples from 5 cattle gave ELISA values greater than 7.0 units. None of these 5 reacted in the tuberculin-test and 2 had no visible lesions. Of the 10 remaining cattle from which M. bovis was isolated, 3 had ELISA values between 6.5 and 7.0 units and were also without visible lesions. The ELISA values for the remaining 7 infected cattle ranged down to 4.6 units. Forty cattle yielded no M. bovis on culture of their tissues. They included 7 which were reactors in the tuberculin test and 23 with ELISA values of 7.0 units or more. The evident low specificity and sensitivity of the ELISA make it of little value as an alternative to the tuberculin test, but it can detect some anergic cattle at the cost of increasing the number of false positive reactors. This may be acceptable in some circumstances and would justify the use of the ELISA as a complement to the tuberculin test or to an in vitro assay of T-cell immunity. In the 2 Northern Territory herds described, the removal of 5 of the anergic cattle would have required a cull of 28 animals of 5% of the total. A cut off value of 6.5 units would have eliminated 3 more, but at the cost of culling 80 animals or nearly 15% of the cattle. Even so, 7 cattle from which M. bovis was isolated would have remained undetected by either test.

Animals↗
PubMed1987

Patterns of junctional communication in animal tissues.

Gap junctions provide pathways for direct communication between cells in almost all animal tissues. The junctional channels are freely permeable to small ions and molecules but not to macromolecules. A coupled cell population is as a consequence a partial syncytium, within which metabolites, cofactors, small control molecules and inorganic ions can all diffuse freely through the combined cytoplasmic compartment, while intracellular macromolecules remain relatively fixed in space, in the cells where they are synthesized. Little is known about the extent and distribution of these communication compartments in tissues. To further understand their significance, we have mapped the patterns of junctional communication in skin by intracellular injection of the tracer dye Lucifer Yellow. Cells in the dermal layer are widely coupled, with dye spreading through hundreds of cells in a few minutes. Dye spread in the epidermis is much more restricted, passing in the same time into only a few cells. Dermal-epidermal coupling is not normally detected but is occasionally seen in new-born mouse skin when hair follicles are starting to invaginate. Dermal cells are coupled to a band of follicular cells near the base of mature hair follicles, whereas sebaceous glands appear to be coupled units, isolated from surrounding cells.

Animals↗
PubMed1986

Patterns of junctional communication in skin.

The patterns of junctional communication in whole skin have been studied by iontophoretic injection of the fluorescent dye Lucifer Yellow CH into excised strips of tissue from newborn (less than 48-h) mice. Sections of injected specimens embedded in resin show that: coupling in the dermis is extensive, the injected dye spreads to more than 500 cells in 5 min; coupling in the epidermis is more restricted, dye spreads to less than 25 cells in 5 min; cells of the epidermis are not detectably dye-coupled to the cells of the dermis except at occasional restricted sites, probably related to hair follicle development; immature sebaceous gland cells are coupled but appear to be isolated from other cell types; and endothelial cells in the dermis are coupled to surrounding fibroblasts.

Animals↗
PubMedDate not supplied

Surgical management of multiple congenital intrahepatic shunts in two dogs: case report.

OBJECTIVE: To present details of an unusual type of portosystemic shunt and its surgical management in two dogs. ANIMALS: Two young dogs that had a tentative diagnosis of a portosystemic shunt on the basis of clinical signs and serum biochemical abnormalities. Abdominal ultrasonography and contrast portography demonstrated multiple intrahepatic shunts. In both cases, the multiple shunts arose from a single branch of the portal vein. OUTCOME: It was possible to locate and attenuate flow through the shunts via a transportal venotomy under conditions of hepatic vascular occlusion. Clinical and biochemical abnormalities resolved after surgery in both dogs. Postoperative sonography revealed complete obliteration of the shunt plexus in one of the dogs.

Animals↗
PubMedDate not supplied

Lateral collateral ligament avulsion of the humeroradial joint in a horse.

This report describes traumatic avulsion of the lateral collateral ligament of the humeroradial joint in a horse. The history and diagnostic procedures are included with relevant radiographs and ultrasonographs. The poor prognosis associated with this injury is due to degenerative joint disease.

Animals↗