Laser flaremetric evaluation of experimentally induced blood-aqueous barrier disruption in cats

OBJECTIVES: To determine whether aqueous humor flare, measured by use of laser flaremetry, was proportional to aqueous humor protein concentration and to use laser flaremetry to evaluate disruption of the blood-aqueous barrier (BAB) in cats. ANIMALS: 30 healthy adult cats. PROCEDURE: Laser flaremetry values for all eyes were compared with aqueous humor protein concentrations determined by use of a Coomassie blue microprotein assay. Laser flaremetry was then performed on both eyes before (0 hours) and 4, 8, and 26 hours after initiation of topical application of 2% pilocarpine (q 8 h) to 1 eye of 9 cats or paracentesis of the anterior chamber of 1 eye of 8 cats. Intraocular pressure and pupil size were also determined. Aqueous humor protein concentration was extrapolated from flare values by use of linear regression. RESULTS: There was a linear relationship between flare values and aqueous humor protein concentrations. Topical application of 2% pilocarpine and paracentesis of the anterior chamber caused a breakdown of the BAB that was detected by use of laser flaremetry. The highest mean flare readings after application of pilocarpine or paracentesis were 24.4 and 132.8 pc/ms, respectively, which corresponded to aqueous humor protein concentrations of 85.5 and 434.9 mg/dl, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Paracentesis of the anterior chamber resulted in a more severe breakdown of the BAB in cats than topical application of 2% pilocarpine. Laser flaremetry may be a useful clinical method to detect increases in aqueous flare and, hence, disruptions of the BAB in cats.     

Brucella intracellular life: from invasion to intracellular replication

Brucella organisms are pathogens that ultimate goal is to propagate in their preferred niche, the cell. Upon cell contact the bacteria is internalized via receptor molecules by activating small GTPases of the Rho subfamily and by a moderate recruitment of actin filaments. Once inside cells, Brucella localizes in early phagosomes, where it avoids fusion with late endosomes and lysosomes. These early events require the control of Rab small GTPases, and cytokines such as the G-CSF. Then, the bacterium redirects its trafficking to autophagosomes and finally reaches the endoplasmic reticulum, where it extensively replicates. Some of the bacterial molecular determinants involved in the internalization and early events after ingestion are controlled by the BvrS/BvrR two component regulatory system, whereas the intracellular trafficking beyond this early compartments are controlled by the VirB type IV secretion system. Once inside the endoplasmic reticulum, Brucella extensively replicates without restricting basic cellular functions or inducing obvious damage to cells. The integrity of Brucella LPS on the bacterial surface is one of the required factors for Brucella intracellular survival, and therefore for virulence.     

In vitro isolation and characterization of bovine Neospora caninum in Korea

The brains of nine aborted bovine fetuses and two newborn calves born from dams suspected to be infected with Neospora caninum were homogenized and inoculated into Vero cells. All fetuses and calves were from cows determined as seropositive to N. caninum by an IFA test. Sera and thoracic fluids of all fetuses and calves also revealed high antibody titer to N. caninum by IFAT ranging from 1:800 to 1:3200. N. caninum was isolated from the brains of one aborted fetus and one newborn calf when the brain homogenates were grown continuously in Vero cell culture. N. caninum tachyzoites, giemsa-positive, were first observed on Days 45 and 56 postinoculation in the newborn calf and the aborted fetus, respectively. The isolates (KBA-1 and KBA-2) were morphologically and ultrastructurally similar to previously published Neospora isolates. The isolated parasites were confirmed as N. caninum by means of the antigenic reactivities, immunostaining, PCR and southern blotting, and electron microscopy.     

Development and validation of a radioimmunoassay for thyrotropin in cattle.

In mammals, thyrotropin, or thyroid-stimulating hormone (TSH), assay is used for the diagnosis of primary hypothyroidism. Hypothyroidism is the most common type of thyroid disorder in cattle. The aim of this study was to develop and validate, under physiologic and pathologic conditions, a radioimmunoassay (RIA) for bovine TSH (bTSH). Double RIA was performed with purified bTSH and specific bovine antiserum. Laboratory validation included research of minimal detection limit, accuracy, and reproducibility. The physiologic validation included a thyrotropin-releasing hormone (TRH) challenge performed on euthyroid cows and a follow-up of bTSH concentration over a 24-hour period. Furthermore, bTSH concentration was assayed in a large population of healthy dairy and beef cows to define reference interval. The pathologic validation was made by assaying bTSH and thyroid hormones on healthy and goitrous newborn calves. The minimum detection limit (MDL) for bTSH assay was 1.3 microU/ml. The recovery was 101% to 106%. The intra- and interassay coefficients of variation (CVs) ranged from 5% to 11% and 11% to 15%, respectively. The RIA covered the whole range of physiologic bTSH values, as shown by bTSH values induced by TRH-challenge. A pulsatile secretion of bTSH was observed, accompanied by a diurnal variation with lower night values than day values. Reference intervals of bTSH ranged from 1.3 to 13.0 microU/ml for beef and dairy breeds. Finally, bTSH easily discriminated goitrous newborn calves from healthy ones, leading to the definition of a cutoff value of 35 microU/ml. The bTSH assay positively reacted to physiologic and pathologic conditions. The accuracy and precision of the RIA were satisfying.     

Are composts from shredded leafy branches of fast-growing forest species suitable as nursery growing media in arid regions?

The morpho-physiological quality of seedlings is negatively affected by the wide scale use of forest soils as substrates in developing countries. With the objective of finding long-term sustainable supply of growing media, compost was produced from shredded branches of three fast growing species (Acacia cyanophylla (AA), Acacia cyclops (AS) and Eucalyptus gomphocephala (EG). The composting process covered three different periods over the course of a year. Pile temperatures were monitored daily and the composts were routinely sampled and analyzed for 19 chemical variables. Although composting is feasible year-round in arid climates, compost produced in the humid cool conditions of autumn, winter and early spring reaches the maturation phase more quickly than compost produced under hot, dry summer conditions. It also requires less turning and water. The evolution of the composting process and quality of the final product can be assessed using three chemical variables (C/N, pH, EC). Seed germination rates in the three types of compost were similar to that in a peat:vermiculite substrate and vigorous high quality seedlings were produced in the two acacia composts. However, compost-grown seedlings had significantly smaller shoots and root systems than those produced in peat substrate. Principal components analyses showed that the quality of a compost-based substrate is reproducible and that its final chemical composition can be predicted from its raw organic materials. The EG composts had higher pH than the acacia composts, whereas the AA and EG composts were higher in mineral salts than the AS.     

Thoracic trauma in newborn foals

In a report describing life ending fractures (255 horses) from the Livestock Disease Diagnostic Center, Kentucky (1993 and 1994), 32 foals had rib fractures. The purpose of our study was to examine the incidence of rib fractures in newborn foals on a Thoroughbred studfarm by physical and radiographic examination, to determine factors which may contribute to the problem and to document any clinical consequences. All foals (263) included were examined within 3 days of birth. The thoracic cage was palpated externally for abnormalities and all foals were placed in dorsal recumbency to evaluate thoracic cage symmetry. Radiographs were used to diagnose foals with thoracic cage asymmetry (TCA) and rib fracture (RF). A diagnosis of costochondral dislocation (CD) was made when no radiographic evidence of fracture was present but there was severe TCA. Fifty-five foals (20.1%) had TCA (9 RF). One to 5 ribs were fractured on 9 of 40 radiographic studies. No consequences of the thoracic trauma was detected clinically, radiographically or ultrasonographically in this group of foals or at a 2- and 4-week follow-up examination. The percentage of foals with a history of abnormal parturition was higher in the TCA foals (15%) compared to the normal foals (6.8%). There were more primiparous dams in the TCA group than in the normal foal group. Fillies (56.6%) had a higher incidence of birth trauma than colts (43.4%). This study demonstrates that thoracic trauma is often present in newborn foals and may not always be of clinical significance. Dystocia foals and foals from primiparous mares should be considered high risk for thoracic trauma.