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Biomedical subjects

A D Thomas

Publications and source records attributed to A D Thomas.

At least 19 recordsLinked to original sources
PubMed1995

Microbiological evaluation of dressing procedures for crocodile carcases in Queensland.

Microbiological testing of crocodiles during the dressing procedure has shown that sanitising the skin before skinning reduces the bacterial count on the skin and that dipping crocodile meat in 1.3% acetic acid solution effectively reduces bacterial levels. The total bacterial count on the processed mean sample was comparable with that obtained in the beef, pork and lamb industries. Salmonellae were isolated from 14 of the 72 carcases. Most (65%) of these isolates were in Salmonella subspecies III, formerly classified as Arizona.

Abattoirs↗
PubMed1994

Mucor amphibiorum in the toad, Bufo marinus, in Australia.

Mucor amphibiorum, a fungus previously found in captive amphibians in Europe and the platypus in Australia, was observed in free-ranging toads, Bufo marinus, in Australia. In tissues the fungus occurred as sphaerules 4.9 to 36.4 microns in diameter; hyphae were not formed. Some spharules developed two to 11 daughter sphaerules internally and these were released into tissues by dissolution of the outer wall. Infected toads were found at 11 sites from nine locations in northern and eastern Australia. The overall prevalence of infection in 3,518 toads was 0.71%. Mucor amphibiorum was isolated from soil at one location.

Animals↗
PubMed1993

Anaphylactoid reaction following local anaesthesia for epidural block.

A potentially serious complication of epidural bupivacaine used for a repeat, elective Caesarean section is presented. The main features of this reaction were erythema, itching, generalised and pulmonary oedema. In addition, pulmonary oedema was subsequently noted in the baby. An immunological hypersensitivity to bupivacaine or lignocaine is the likely cause.

Adult↗
PubMed1992

The regulation of expression of the porin gene ompC by acid pH.

The regulation of expression of the porin genes of Escherichia coli by acid pH was investigated using reporter gene fusions. The ompC-lacZ gene fusion was expressed in response to acidification of the external medium. The kinetics of beta-galactosidase synthesis under acid-induction differed significantly from those obtained under conditions of osmotic stress. The latter led to rapid induction without a lag, followed by establishment of a rate that was equal to the growth rate; acid-induction was frequently preceded by a short lag period, was relatively slow and did not achieve a rate that was in balance with the growth rate. Further, induction of the ompC gene at acid external pH was dependent upon the presence of glucose as sole carbon source; growth with either glycerol or succinate as sole carbon source reduced induction of ompC at acid pH. Osmotic induction was independent of carbon source. The induction of the ompC gene at acid pH was also reduced by addition of cAMP to the growth medium. The porins are known to be subject to catabolite repression and our data are consistent with the exposure to acidic pH resulting in progressive changes in the state of catabolite repression. Acidification of the cytoplasm also provoked a rapid induction of the ompC-lacZ gene fusion. The kinetics of induction resembled the response to osmotic upshock. This response was independent of the identity of the carbon source supplied for growth. The contribution of changes in cytoplasmic pH to the induction of ompC at acid pH is discussed.

Bacterial Outer Membrane Proteins↗
PubMed1992

The Hough transform for locating cell nuclei.

A method of cytologic image segmentation that works purely on the basis of geometric information is described. Cell nuclei are assumed to be circular or elliptical. The latest ellipse-finding Hough transform is then used to locate the nuclei. The results are encouraging.

Cell Nucleus↗
PubMed1991

Does propofol have an anti-emetic effect? A prospective study of the anti-emetic effect of propofol following laparoscopy.

In order to investigate the putative anti-emetic effect of propofol, 53 patients undergoing gynaecological laparoscopy were given a standard anaesthetic including induction with thiopentone. At the end of surgery, the patients received either a sub-anaesthetic does of propofol or an equivalent volume of normal saline. There was no difference in the incidence of nausea and vomiting between the propofol and control group. It is concluded that low-dose propofol does not have an anti-emetic effect.

Adult↗
PubMed1990

Experimental infection of normal and immunosuppressed pigs with Pseudomonas pseudomallei.

A single dose of 5 x 10(8) bacilli of Pseudomonas pseudomallei by intratracheal injection resulted in acute (21 cases) or chronic (19 cases) melioidosis in 40 of 48 pigs. Fifteen (10 acute and 5 chronic) had been immunosuppressed by cyclophosphamide before inoculation. The major clinical signs were initial fever, marked neutrophilia and, in the acute cases, respiratory distress. There were no signs of the nasal and ocular discharge, paresis or diarrhoea seen in acute cases in south-east Asia. The cyclophosphamide treatment caused a significant decrease in the neutrophil count by 7 d after inoculation in all 15 immunosuppressed pigs, and all were culture positive at necropsy. Eight of the 33 non-treated pigs were culture negative at necropsy. Pigs overcoming the initial phase of infection had more abscess-like nodules that were bacteriologically sterile at necropsy than the pigs with acute cases of melioidosis. P. pseudomallei was isolated predominantly from the spleen, lungs and the injection site. Although only one strain was used in this study, it is likely that Australian strains of P. pseudomallei are not as virulent as the south-east Asian isolates.

Acute Disease↗
PubMed1990

Evaluation of a modified complement fixation test and an indirect hemagglutination test for the serodiagnosis of melioidosis in pigs.

A complement fixation test modified by the addition of porcine serum and an indirect hemagglutination test were used to detect antibodies to Pseudomonas pseudomallei in pigs. These tests together with cultural examinations were carried out with 250 pigs. The sensitivity and specificity values were 79.3 and 99.5% and 82.8 and 93.2% for the modified complement fixation and hemagglutination tests, respectively. When results from the combination of both tests were considered, the values were 86.2 and 92.8%, respectively.

Animals↗
PubMed1988

Orphaned kangaroo and wallaby joeys as a potential zoonotic source of Salmonella spp.

Sixteen serotypes of Salmonella spp. were isolated from 37 (26.8%) of 138 orphaned kangaroo and wallaby pouch-young which were in the care of guardians in north Queensland. Sal. lansing, Sal. virchow and Sal. wandsworth were the most prevalent serotypes. Orphaned macropodid joeys are a potential source of zoonotic infection for Salmonella spp. and recommendations to reduce the risk of transmission to humans are presented.

Adult↗
PubMed1988

Clinical and pathological observations on goats experimentally infected with Pseudomonas pseudomallei.

The effects in goats of the subcutaneous injection of varying doses of Pseudomonas pseudomallei (90 to 500,000 bacilli) suspended in normal saline are described. High doses (greater than or equal to 500 bacilli) caused acute, fatal infections. Lower doses (90 to 225 bacilli) caused acute or chronic disease when infection became established. However, 11 of 18 goats injected with the lower doses of bacilli showed no sign of infection on clinical or bacteriological examination. Response to antibiotic therapy with long acting tetracycline and chloramphenicol was minimal. Goats surviving the initial phase of infection tended to overcome the disease with a corresponding increase in the number of abscesses that were sterile at necropsy. In infected goats, clinical signs included undulating fever, wasting, anorexia, paresis of the hind legs, severe mastitis and abortion. At necropsy, abscesses were found predominantly in the spleen, lungs, subcutaneous injection site and its draining lymph node.

Animals↗
PubMed1988

Pathological findings in the bulbourethral glands of bulls.

The bulbourethral glands of 323 Bos indicus or B. indicus crossbred bulls more than 1 1/2 years old were examined in an abattoir study. Bulbourethral adenitis was diagnosed grossly and confirmed by histological examination in 4 (1.2%). Unilateral chronic interstitial inflammation was seen in 2 cases; one of these was associated with a degenerative-type seminal vesiculitis. In the others adenitis was bilateral; in one case it was associated with a concretion and foreign (plant) material in the principal duct of the left bulbourethral gland; in the other bilateral case, numerous calculi were present and microscopically, a chronic active and diffuse inflammation was observed. Chemical analysis of the calculi showed calcium oxalate and tricalcium phosphate to be the most important components. Corynebacterium spp was isolated from the lesion with multiple calculi but attempts to isolate Chlamydia spp, Mycoplasma spp and Brucella abortus from the 4 adenitis cases were unsuccessful. Congenital abnormalities such as glandular fusion (2.2%) or unilateral aplasia (0.6%) were also observed. Cysts were the most common finding (19.2%), and duct dilation was frequent (7.1%). The significance of these findings in relation to fertility is considered.

Animals↗
PubMed1988

Evaluation of four serological tests for the diagnosis of caprine melioidosis.

A complement fixation (CF) test, 2 indirect haemagglutination (IHA-A; IHA-L) tests which differed in antigen preparation and technique, and a microtitre agglutination (MA) test were compared in the serodiagnosis of melioidosis in goats. One hundred and eighteen experimental serums and 3143 field serums from goats in endemic and non-endemic areas of north Queensland were used in the evaluation. Culture of samples for Pseudomonas pseudomallei from 112 goats provided substantiating evidence of infection. The IHA-A test was the most sensitive, and the CF test the most specific. We advocate the use of the IHA-A as a screening test followed by the CF test for confirmation of active melioidosis. The IHA-A test is the better indicator of past infection.

Acute Disease↗
PubMed1987

Chronic learning problems and maturation.

An analysis of test scores of a longitudinal sample of normal children, who placed in the lowest quartile of the class on the California Achievement Test and children in the highest quartile yielded significant differences on three perceptual-motor tests and on Piaget's preoperational and precausal tests at Kindergarten level. Although matched for IQ in Kindergarten, significant IQ differences appeared in Grade 1 and continued to increase over 5 yr., as those on other tests. Cattell's Early School Personality Questionnaire indicated that low achievers were significantly less mature and more tense and anxious than high achievers from Grades 1 through 5. Maturational lag is hypothesized for retardation of learning.

Child↗
PubMed1986

Melioidosis in intensive piggeries in south eastern Queensland.

The epidemiology of melioidosis was investigated in 8 intensive piggery units which used water from the same river in south eastern Queensland. In 3 consecutive years cases of disease followed heavy rainfall and flooding. Although Pseudomonas pseudomallei was not isolated from water or soil samples the water supply was suspected as the source of infection. Affected pigs were detected at slaughter by the presence of abscesses most commonly in the bronchial lymph nodes (40%) and spleen (34%). One hundred and fifty nine cases were observed at slaughter from a total of 17,397 animals at risk. Infection by inhalation of water aerosols derived from nipple drinkers, hose sprays and a water misting cooler was considered to be responsible for the bronchial lymph node lesions. These outbreaks occurred outside the area in which melioidosis is generally regarded as being endemic.

Animals↗