Biomedical subjects
Publications and source records attributed to D J Farrell.
A rare case of primary malignant melanoma of the bronchus is described. Before considering this diagnosis, metastasis from an occult primary must be convincingly excluded and the tumour should conform to certain guidelines. This patient presented with a solitary lung tumour for which she underwent left lower lobectomy and continues to be tumour free 54 months after surgery. Two possible mechanisms of aetiology are suggested.
Mast cells are known to be present in human liver but their distribution and density in normal livers and in chronic liver diseases have not previously been examined. In this study, we quantified mast cell numbers and examined their distribution in percutaneous biopsy specimens from normal livers (n = 8) and in two chronic progressive liver diseases: primary biliary cirrhosis (PBC) (n = 40) and alcoholic liver disease (n = 33). We compared differences in mast cell density between these two forms of chronic liver disease because it had been suggested that mast cells may play a role in the development of liver fibrosis, particularly in patients with chronic cholestatic liver disease who frequently have increased plasma histamine levels. Mast cells were identified by immunohistochemistry using a specific monoclonal antibody (AA1) raised against mast cell tryptase after an initial study showed this to be more sensitive for the detection of mast cells than the conventional histochemical stain, toluidine blue. Our results showed that small numbers of mast cells (3.9 +/- 3.3/mm2) are present within the portal tracts and sinusoids of normal livers. In progressive chronic liver disease, increased numbers of mast cells were present, which correlated with the increasing amounts of liver fibrosis present. We found significantly more mast cells in the PBC group compared with the alcoholic group for a given amount of fibrosis. Our findings suggest that mast cells and their mediators may play a role in liver fibrogenesis.
We report a case of multiple hepatic abscesses due to Yersinia enterocolitica in a 58 yr old male. This case is typical of the other 39 cases reported in the literature in that the patient had alcoholism, malnutrition, iron overload and a subsequently diagnosed malignancy. Ultrasound showed multiple hypoechoic areas in the liver which were confirmed by CT scan. The patient also had a rectal lesion initially thought to be malignant, leading to a presumptive diagnosis of metastatic disease. A CT-guided fine needle aspiration biopsy of a liver lesion unexpectedly revealed pus which subsequently grew Yersinia enterocolitica. The organism was also isolated from the patient's blood and feces. This case illustrates the need for histological microbiological investigation of radiologically diagnosed presumptive malignancy.
Cutaneous lesions caused by M. ulcerans were shown to bear only a superficial resemblance to those produced by certain spider species. M. ulcerans was not found in either the venoms or the midguts of several Australian spiders, and deliberate contamination by inoculation of the fangs and digestive system of the wolf spider, Lycosa godeffroyi, did not result in permanent colonization. M. ulcerans was successfully introduced into the skin of mice through a small trauma site similar to that caused by a spider bite. However, because M. ulcerans was shown to survive on exposed surfaces for only a short period, a successful inoculation is likely only if the skin is contaminated with this organism after, or at the same time as, the skin suffers damage. The claim by other workers that M. ulcerans produces cutaneous ulcers by release of an exotoxin could not be confirmed. The authors conclude that M. ulcerans is not involved in most cases of necrotic arachnidism and hence there is no justification for prescribing anti-mycobacterial antibiotics to resolve alleged spider bite lesions unless the presence of M. ulcerans has been demonstrated by appropriate laboratory tests.
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Neonatal infection due to Haemophilus influenzae has several clinical similarities to infection by the more common Streptococcus agalactiae (Strep group B). A high frequency of H. influenzae biotype IV in association with genital, maternal and neonatal infections has been reported in the literature, suggesting this biotype has an affinity for the female genital tract. Cefotaxime should be considered as part of the treatment regimen when this organism is suspected because of the emerging resistance of H. influenzae to ampicillin. We present a case of H. influenzae biotype IV infection in a premature (32 weeks) neonate.
Controversy reigns over the role of Ureaplasma urealyticum in determining pregnancy outcome. U. urealyticum infection of the chorioamnion is strongly associated with chorioamnionitis (1-3), premature birth (2-4), and perinatal morbidity (4-6). We present 4 cases of U. urealyticum chorioamnionitis and associated morbidity and mortality.
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1. Several growth factors important in liver regeneration and fibrosis stimulate phospholipase D in plasma membranes via a receptor/G-protein-coupled mechanism resulting in hydrolysis of phosphatidylcholine to phosphatidate. Phosphatidate can be further hydrolysed to diacylglycerol by phosphatidate phosphohydrolase. Phosphatidate and diacylglycerol can act as 'second-messengers' and regulation of phosphatidate phosphohydrolase activity could control the balance between them. 2. A form of phosphatidate phosphohydrolase, located in the plasma membrane and insensitive to inhibition by N-ethylmaleimide, has recently been identified that is distinct from the 'metabolic' form, which is present in the cytosol and microsomes and is sensitive to N-ethylmaleimide. 3. We have investigated the hypothesis that the balance between regeneration and fibrosis is, in part, determined by the activity of plasma membrane phosphatidate phosphohydrolase through its effect on the phosphatidate/diacylglycerol ratio. N-Ethylmaleimide-insensitive and -sensitive phosphatidate phosphohydrolase activities were measured in three hepatic conditions characterized by regeneration and/or fibrosis: alcoholic liver disease in humans (regeneration and fibrosis) and rat livers after either acute CCl-4-induced injury (regeneration) or common bile duct ligation (fibrosis). 4. In patients with alcoholic liver disease, N-ethylmaleimide-insensitive phosphatidate phosphohydrolase activity was higher in cirrhotic biopsies (5.82 +/- 0.3 nmol of Pi min-1 mg-1 of protein, n = 19) than in non-cirrhotic biopsies (2.17 +/- 0.2, n = 23) or in wedge biopsies from healthy subjects undergoing routine cholecystectomy (2.16 +/- 0.5, n = 6).(ABSTRACT TRUNCATED AT 250 WORDS)
Two experiments were conducted to determine the available P requirements of grower and grower/finisher pigs and to define the conditions for conducting a growth assay for P availability. In the first experiment, diets with four levels of calculated available P (1-4 g/kg) and four Ca:available P ratios (1.7-2.9) were used to determine the available P requirements of grower pigs. The diets were formulated by substituting the required amounts of limestone and sodium tripolyphosphate for sugar in a soya-bean meal and sugar-based diet. In addition to measuring growth responses, a range of bones were examined to determine the most suitable criteria for assessing the response to available P. There was a small quadratic response of feed intake and growth rate of the pigs to level of available P, with maximum responses occurring to approximately 3 g available P/kg (P < 0.05). There were linear depressing effects of increasing Ca:available P ratios on carcass gain and feed conversion ratio (P < 0.01) but most of these effects occurred when the ratio exceeded 2.5:1. All bone variables examined increased linearly (P < 0.05) or curvilinearly (P < 0.01) with increasing available P concentration. In general, these variables were not affected by the Ca:available P ratio. The results of the growth responses and bone development indicate that the grower pig requires approximately 3 g available P/kg. However, for availability assays, where linearity of response is needed, the dietary concentration of available P should be a maximum of approximately 2 g/kg. In the second experiment four levels of calculated available P (1-4 g/kg) with a Ca:available P ratio of 2.5:1 were used to determine the available P requirements of grower/finisher pigs from 20 to 90 kg live weight. At 50 kg live weight the dietary available P concentration for half the pigs fed at 2, 3 and 4 g available P/kg was reduced to 1, 2 and 3 g/kg respectively. The pigs were fed ad lib, and growth performance, bone characteristics, P retention and ash concentration in the empty body were taken as response criteria to assess P adequacy. Among the variables tested, the ash concentration in the radius/ulna bone and P and ash concentrations in the empty body appeared to be more responsive than other variables to the changes in dietary P levels.(ABSTRACT TRUNCATED AT 400 WORDS)
Experiments were conducted with pigs and rats to determine the availability of P in feeds. Initially, the availability of P in a soya-bean meal and field peas (Pisum sativum cultivar Early Dun) was assessed using a slope-ratio assay for grower pigs. Three different levels of either monosodium phosphate (MSP), soya-bean meal or field peas were added to a basal sucrose-soya-bean meal diet (2.5 g/kg P) to give three levels of P (3.0, 3.5 and 4 g/kg) for each source. The diets were offered for 35 d at three times maintenance energy requirements to female pigs initially weighing 20 kg live weight. Several bone variables and the ash and P concentration and retention levels in the empty body were used as criteria of availability. The responses to MSP were linear for all variables. However, responses to P in the test proteins, particularly soya-bean meal, were mostly non-linear, except for ash and P concentrations and retentions in the empty body. The estimates of P availability in the soya-bean meal and in the field peas were dependent on the criteria used to assess availability. Using bone variables as the criterion, the availabilities of P in soya-bean meal and field peas were approximately 0.17 and 0.38 respectively. Using ash or P concentrations or retentions in the empty body as the response criterion, the availabilities of P in soya-bean meal and field peas were 0.61 and 0.38 respectively. The mean retention values for P from MSP, soya-bean meal and field peas were 0.74, 0.33 and 0.21 respectively. Experiments were then conducted to define the conditions necessary for a slope-ratio assay for P availability with growing rats to determine if they could be used as a model to assess P availability for pigs. These experiments examined level of P in the diet, the effect of Ca:P ratio and criteria for assessing response (growth rate, feed intake, feed conversion ratio, bone ash and bone bending moment). The results indicated that a suitable range of dietary P for a slope-ratio assay in rats was 1.8-3.5 g/kg, with Ca:P ratio of between 1.3 and 6.2, and that ash content or bone bending moment of the femur bone were suitable criteria of response. However, using bone bending moment as the criterion of response, the availability of P in soya-bean meal was 0.81, which was considerably higher than the estimate with pigs.(ABSTRACT TRUNCATED AT 400 WORDS)
Two experiments were conducted (1) to determine the effects of phytase (EC 3.1.3.26) on the digestibility and availability of P in soya-bean meal for growing pigs and (2) to compare growth v. digestibility variables for assessing the availability of P. In the first experiment the effect of phytase on P availability was assessed in a growth assay using a slope-ratio design of treatments. Two different levels of either monosodium phosphate (MSP) or soya-bean meal were added to a basal sugar-soya-bean-meal diet (2.5 g P/kg) to give two levels of P (g/kg): 3.25 and 4.0 for each source. An additional five diets were supplemented with phytase. The ten diets were offered ad lib. for 35 d to female pigs initially weighing 20 kg live weight. In addition, the relative effectiveness of different variables for assessing P availability were compared: bone bending moment, ash in various bones, and ash and P in the empty body. The addition of phytase increased growth rate (g/d) (741 v. 835; P < 0.05), lowered the food conversion ratio (2.37 v. 2.16; P < 0.01), and increased protein deposition (g/d) (108 v. 123; P < 0.05), protein retention (kg/kg) (0.33 v. 0.36; P < 0.05), energy retention (MJ gross energy/MJ digestible energy) (0.36 v. 0.38; P < 0.05) and the availability of P in soya-bean meal from 0.11 to 0.69 when bone bending moment was the criterion of availability. All other criteria for assessing availability were unsuitable. In the second experiment the availability of (P) in soya-bean meal was assessed in a digestibility experiment with grower pigs using diets 1-5 as for Expt 1 arranged in a slope-ratio design of treatments. In addition, the effects of phytase supplementation on the apparent digestibility of P, dry matter, crude protein (N x 6.25) and energy were determined. The diets were offered at three times maintenance energy requirements to male pigs initially weighing approximately 30 kg live weight and total collection of faeces was conducted over a 10 d period. The availability of P in the soya-bean meal was 0.66 using digestible P intake as the criterion of response. The apparent digestibility of P in soya-bean meal was 0.42. Phytase supplementation increased the apparent digestibility of soya-bean meal P to 0.69 (P < 0.01) but had no effect on the faecal digestibility of dry matter or crude protein.(ABSTRACT TRUNCATED AT 400 WORDS)
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We report a case of multilobated B-cell lymphoma presenting with primary splenic involvement. This is a very unusual tumour occurring in an uncommon site.
Fasting and fed metabolic rates were measured in three species of potoroine marsupials, the rufous rat-kangaroo (Aepyprymnus rufescens), the long-nosed potoroo (Potorous tridactylus) and the brush-tailed bettong (Bettongia penicillata). There were no significant differences among potoroine species in fasting metabolic rate. The lowest fasting heat production for each species was 11-20% less than the interspecific value of 295 kJ.kg-0.75.day-1 for basal metabolism of mature, non-reproductive eutherian homeotherms. The respiratory quotient of all species was reduced significantly as starvation proceeded, but only for B. penicillata was there a significant effect of starvation duration on fasting heat production. The night-time activity of P. tridactylus and B. penicillata doubled their daytime fasting heat production; the corresponding increase for A. rufescens was only 25%. The calorimetric measurement of fed animals showed no differences in digestible energy or metabolisable energy between species. Nevertheless, P. tridactylus and B. penicillata produced more heat per unit metabolic body mass. The maintenance energy requirements (kJ.kg-0.75.day-1) were 479, 494 and 345 for P. tridactylus, B. penicillata and A. rufescens, respectively. The net availability of metabolisable energy was about 0.70 in the three species. The combined heat production of fed female A. rufescens and their pouch young stayed relatively constant for the first two-thirds of pouch life, after which it rose sharply (20%) in response to the rapid growth of the young. Only during the last week of pouch life did the female enter negative energy balance. There was no indication that the metabolism of the female increased in response to the presence of a pouch young. The presence of pouch young did not alter the efficiency of utilisation of metabolisable energy. The daily energy requirement for maintenance was 0.83 MJ.day-1 or 0.36 MJ.kg-0.75.day-1.
1. Three experiments were performed to examine practical methods of early-life food restrictions and to examine the influence of increased dietary lysine or methionine on bodyweight recovery during re-alimentation in broiler chickens. 2. Food intake of broiler chicks was restricted quantitatively or by dietary dilution at 3 ages and the birds slaughtered at 49 d of age. The success of each food restriction was measured in terms of bodyweight recovery and body fat content. 3. Discontinuous food restriction and restriction by dietary dilution produced similar effects to a previously established food restriction regime. Bodyweight recovery was complete and fat contents depressed. FCR was inconsistently affected. 4. Supplementation of the finisher diet with lysine and/or methionine produced no conclusive results when this diet was fed to broilers previously subjected to early-life food restriction.
1. The physiological and metabolic effects of a short term food restriction of broiler chickens at an early age and grown to 49 d of age were examined. 2. Fat accretion was measured by tritium dilution. Adipocyte characteristics of the fat tissue were examined by cell counting after fixation with osmium tetroxide and the metabolic effects of food restrictions were measured by closed-circuit respiration calorimetry. 3. The success of food restrictions in allowing full bodyweight recovery and producing decreases in body fat was associated with a negative energy balance and a positive nitrogen balance achieved during the restriction phase. 4. Food restrictions produced decreases in body fat possibly by causing a delay in adipocyte hyperplasia. Excess dietary energy was then lost as heat until adipocyte hyperplasia re-commenced allowing the bird to store surplus dietary energy as fat. 5. A food restriction that allows full bodyweight recovery and maximum carcase fat reduction in the broiler chicken at 49 d may not be appropriate for birds grown for longer periods.
Campylobacter species are known to cause infectious abortion in domestic animals. In humans, Campylobacter are an important cause of enteritis, an occasional cause of systemic infection and have had a rare association with abortion and perinatal infection. A case history of spontaneous abortion, at 26 weeks' duration, associated with maternal bacteraemia, due to Campylobacter coli is presented. Transmission, pathogenesis, treatment, and the need for further investigation are discussed.