UV‐B radiation constrains the photosynthesis of Quercus robur through impacts on the abundance of Microsphaera alphitoides

Quercus robur saplings were exposed at an outdoor facility in the UK to supplemental levels of UV‐B radiation (280–315 nm) under arrays of cellulose diacetate‐filtered fluorescent lamps which also produced UV‐A radiation (315–400 nm). Saplings were also exposed to supplemental UV‐A radiation under arrays of polyester‐filtered lamps and to ambient levels of solar radiation under arrays of unenergized lamps. The UV‐B treatment was modulated to maintain a 30% elevation above the ambient level of erythemally weighted UV‐B radiation. Naturally occurring infections by oak powdery mildew (Microsphaera alphitoides) were more abundant, and developed more rapidly, on lammas leaves of saplings which were exposed to treatment levels of UV‐B radiation than on leaves of saplings exposed to supplemental UV‐A or to ambient levels of solar radiation over 12 weeks in summer and autumn 1996. An analysis of leaf photosynthetic capacities revealed that M. alphitoides infection reduced the quantum efficiency of photosystem (PS) II by 14% at moderate irradiance. Although there was no direct effect of UV‐B radiation on PSII photochemistry, exposure of saplings to supplemental UV‐A radiation under polyester‐filtered lamps resulted in a 17.5% decrease in PSII quantum efficiency, compared with saplings exposed to ambient solar radiation. The results from our study suggest that photosynthesis of Q. robur may be constrained by exposure to UV‐B radiation in the natural environment through impacts on the abundance of M. alphitoides.     

Clinicopathological findings associated with feline infectious peritonitis in Sydney, Australia: 42 cases (1990-2002)

Objectives To review the clinicopathological findings in naturally-occurring, histopathologically confirmed cases of feline infectious peritonitis in client-owned cats in Sydney, Australia, with the purpose of identifying factors assisting in the diagnosis of this complex disease syndrome and to characterise the disease as it occurs in this region.
Design Retrospective clinical study: the clinical records of all cats with histopathologically confirmed feline infectious peritonitis at the University Veterinary Centre Sydney and a private cat hospital in Sydney between 1990 and 2002 were reviewed for signalment, history, physical findings, diagnostic test results and the distribution of histological lesions throughout the body at necropsy.
Results Forty-two cats met the inclusion criteria. Significant features of this study that unique to the contemporary literature are i) the over-representation of certain breeds (Burmese, Australian Mist, British Shorthaired, and Cornish Rex) and the under-representation of other breeds (Domestic Shorthaired, Persian); ii) the overrepresentation of males; iii) the tendency for effusive disease in Australian Mist cats and non-effusive disease in Burmese; iv) the even age distribution of disease seen in cats older than 2 years-of-age; and v) the presence of fulminant immune-mediated haemolytic anaemia in two cats in this study.
Conclusion The study highlights the diverse range of clinical manifestations and the complexities experienced by clinicians in diagnosing this fatal disease. Some aspects of the epidemiology and clinical manifestations of feline infectious peritonitis appear different to the disease encountered in Europe and North America, most notably the over-representation of specific breeds and the presence of immune-mediated haemolytic anaemia.     

Ear temperatures in the horse during recovery from anesthesia

Ear temperatures were measured during and after halothane anesthesia in 16 horses and ponies. Aural hypothermia developed during recovery and persisted for more than one hour following standing. The decreased ear temperature was attributed to decreased peripheral perfusion and was considered to be related to other cardio-pulmonary and neuro-endocrine derangements that occur during recovery.     

Feline miliary eczema: megestrol acetate does not suppress immune responses

Megestrol acetate was found to have no influence on immunological skin and corneal reactivity nor on antibody responses in guinea pigs. Its curative effect in feline miliary eczema is probably not, therefore, the result of interference with the immune response.     

Squamous cell carcinoma of the nasal planum in 17 dogs

Squamous cell carcinoma of the nasal planum was diagnosed in 17 dogs over a period of 11 years. Ulceration, bleeding and sneezing were the most common clinical signs. One dog had cytological evidence of metastasis to the local lymph node. The dogs were treated by surgical resection, fractionated megavoltage irradiation, or a combination of the two. Surgical resection gave the most favourable results; four of six dogs were cured but a recurrence of the tumour was predicted in the other two on the basis of incomplete or marginal resection. Radiotherapy alone was not as effective; one of four dogs was cured, and the tumour recurred in the others within 24 weeks (median eight weeks). Combined surgical resection and radiotherapy did not produce a cure in any of the seven remaining dogs, and the tumour recurred within 12 weeks (median nine weeks). Three dogs had cytological evidence of lymph node metastasis when the tumour recurred. The dogs' prognosis was adversely affected by the interval between their initial examination and treatment, but there was no apparent association between the histological grade of the tumour and the clinical outcome.     

Regulation of bovine pyruvate carboxylase mRNA and promoter expression by thermal stress

Pyruvate carboxylase (PC) catalyzes the rate-limiting step in gluconeogenesis from lactate and is a determinant of tricarboxylic acid cycle carbon flux. Bovine PC 5' untranslated region (UTR) mRNA variants are the products of a single PC gene containing 3 promoter regions (P3, P2, and P1, 5′ to 3′) that are responsive to physiological and nutritional stressors. The objective of this study was to determine the direct effects of thermal stress on PC mRNA and gene expression in bovine hepatocyte monolayer cultures, rat hepatoma (H4IIE) cells, and Madin-Darby bovine kidney epithelial (MDBK) cells. Hepatocytes were isolated from 3 Holstein bull calves and used to prepare monolayer cultures. Rat hepatoma cells and MDBK cells were obtained from American Type Culture Collection, Manassas, VA. Beginning 24 h after initial seeding, cells were subjected to either 37°C (control) or 42°C (thermal stress) for 24 h. Treatments were applied in triplicate in a minimum of 3 independent cell preparations. For bovine primary hepatocytes, endogenous expression of bovine PC mRNA increased (P < 0.1) with 24 h of thermal stress (1.31 vs. 2.79 ± 0.49, arbitrary units, control vs. thermal stress, respectively), but there was no change (P ≥ 0.1) in cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) mRNA expression. Similarly, exposure of MDBK cells to thermal stress increased (P < 0.1) expression of bovine PC mRNA without altering (P ≥ 0.1) PEPCK-C mRNA expression. Conversely, there was no effect (P ≥ 0.1) of thermal stress on endogenous rat PC (0.47 vs. 0.30 ± 0.08, control vs. thermal stress) or PEPCK-C (1.61 vs. 1.20 ± 0.48, arbitrary units, control vs. thermal stress, respectively) mRNA expressions in H4IIE cells. To further investigate the regulation of PC, H4IIE cells were transiently transfected with bovine promoter-luciferase constructs containing either P1, P2, or P3, and exposed to thermal stress for 23 h. Activity of P1 was suppressed (P < 0.1) 5-fold, activity of P2 was unchanged (P ≥ 0.1), and activity of P3 was increased (P < 0.1) by 5.4-fold. These data indicate that response of bovine PC gene to thermal stress is through promoter regulation and suggest that there are unique characteristics of bovine PC promoters that may contribute to the physiological response to thermal stress.