Immunohistochemical localization of distinct angiotensin II AT1 receptor isoforms in the kidneys of the Sprague-Dawley rat and the desert rodent Meriones crassus

Employing a purified lgG fraction of a polyclonal anti-AT1 receptor anti-body, raised against a synthetic octapeptide encompassing residues 14-21 of the first extracellular domain of the AT1 polypeptide, selective AT1 receptor expression was immunohistochemically demonstrable within renal structures in Sprague-Dawley (SD) rats and the desert rodent Meriones crassus. In both animal models, prominent AT1 receptor labelling was evident in renal vascular elements, particularly cortical inter-lobular arteries (IA) as well as vasa recta bundles in the inner stripe of the outer medulla. Less intense labelling was observed among peritubular capillary endothelia within the deep cortex, and at both the outer stripe and the inter-bundle regions of the inner stripe of the outer medulla. The binding of the anti-peptide anti-body was, however, lacking among glomeruli and, except for the intense labelling confined to basement membranes of Bowman's capsule of deep nephrons, was virtually absent in all renal tubular structures of both animal models. Structural assessment of the expressed AT1 receptors by two-dimensional Western blotting revealed that a spectrum of structurally distinct AT1 receptor isoforms is expressed in the renal tissues of both animal models. This spectrum was constituted by isoforms of equal size (70 kDa) but distinct pls in SD rats, and of both different sizes (67-73 kDa) and isoelectric points in M. crassus. In either species, the charge and/or size heterogeneity of AT1 receptor isoforms may be attributed in part to differential post-translational glycosylation mechanisms of the AT1 receptor polypeptide backbone. The potential for the differential glycosylation state of AT1 receptors to alter recognition properties may add another level of complexity to tissue-specific and/or species-specific mechanisms underlying angiotensin II interactions in the kidney.     

Journey length and high temperatures: effects on rabbit welfare and meat quality

The transport of domestic animals by road can increase levels of stress and decrease meat quality, especially in unfavourable climates. The purpose of this study was to investigate the effect of journey duration and vertical position on the transport truck on some physiological indicators of stress and on instrumental meat quality parameters in commercial rabbits. In the summer months (June and July, 2003), 78 rabbits were subjected to either long (7 h) (LJ) or short (1 h) (SJ) journeys (3 replicates each, n = 6) between the farm and an abattoir in northern Spain. The position (top, middle, or bottom) occupied by the rabbits on the Multi-Floor cage Rolling Stand (MFRS) of the transport truck was recorded. Blood samples were collected at sticking and meat pH was measured at 24 h post-mortem (pH24). At 48 h post-mortem, samples of the M. longissimus dorsi were used to determine water-holding capacity (WHC) and instrumental tenderness using an INSTRON machine. The levels of corticosterone, glucose, lactate, and creatine kinase were slightly higher in LJ than in SJ samples, but the difference was not statistically significant (p < or = 0.10). Independent of journey length, rabbits in the middle and bottom of the MFRS showed higher levels (p < or = 0.05) of glucose and creatine kinase (middle), and corticosterone (bottom) than the rabbits located at the top floor. The pH 24 and WHC values of the SJ and LJ rabbits did not differ significantly. Journey length had a significant effect (p < or = 0.01) on meat tenderness. The meat from rabbits subjected to LJ had higher values of maximum stress and total toughness than did the SJ rabbits (p < or = 0.05). There were similar differences (p < or = 0.05) between LJ and SJ rabbits in their stress values of compression at 20% and 40% (measures of the tenderness of raw meat). In hot weather, the position on the transport truck appeared to have a greater effect on rabbit welfare than the duration of the journey.     

Trends in the incidence of tuberculosis in possums and livestock, associated with differing control intensities applied to possum populations

AIM: To determine the trap-catch index (an estimate of abundance) of brushtail possum (Trichosurus vulpecula) populations infected with bovine tuberculosis (Tb; Mycobacterium bovis) that must be achieved, and the length of time such an index must be maintained, for Tb to be eliminated from possum populations and adjacent livestock. METHODS: Between 1997-1998 and 2000-2001, trap-catch surveys of possum populations naturally infected with Tb and subjected to population-control measures were undertaken at four forest sites and two farmland sites. At the same time, possum carcasses were collected at these sites and their Tb status determined, and all contiguous cattle and deer herds were Tb tested and abattoir slaughter data for these herds were interrogated. RESULTS: Trap-catch surveys indicated that numbers of possums on the farmland sites surveyed were usually very low and well below the control targets set (i.e. a 5% trap catch or approximately 0.5-1 possum/ha) for the study. In contrast, trap-catch surveys undertaken in forest sites indicated possum numbers were more variable, and often recovered rapidly from control operations to exceed control targets within 1-3 years. The annual rate of recovery of possum populations in half of the forest population surveys undertaken exceeded published intrinsic rates of increase for possums. The overall prevalence of Tb in possum populations was < or =1.9% at 5/6 sites, and was 6.5% at the sixth site. Juvenile possums infected with Tb were trapped within but near the edge of control zones and appeared to represent an immigrant source of infection. Mature infected possums survived control operations apparently by having home ranges in uncontrolled patches within control areas. Infection in possums appeared to be eliminated from one study site by the intensive control undertaken, but elimination at other sites appeared less likely. Levels of Tb in livestock on or adjacent to the study sites fell by at least 50% during the study, and cattle in one area tested clear for the first time in 20 years. CONCLUSIONS: Initial control of possums in forest appeared to achieve national control targets set by the Animal Health Board (AHB), despite trap-catch data often providing misleading population estimates. Such targets were often exceeded within 1-3 years. By comparison, possum control on farmland appeared to maintain populations at very low levels, while control on forest margins maintained populations at intermediate levels. Control was least effective in deep forest where human access was most difficult. Intensive population control measures appeared to have led to a reduced incidence of Tb in livestock at 3/4 sites, and elimination of Tb in livestock at one site. This result supports modelling studies that predict the eradication of Tb from possums through ongoing intensive control and may explain the lower success achieved with earlier less-intensive possum control.     

The metabolite products of chlorocholine chloride (CCC) in eggs and meat of laying hens fed 15N-CCC containing diets

An experiment was conducted to evaluate the metabolic products of chlorocholine chloride (CCC) in eggs and meat of laying hens fed a diet containing (15)N-CCC. Ten brown laying hens were randomly divided into two groups of five each. One group was offered (15)N-CCC free diet while the other group received a diet with 100 ppm (15)N-CCC for 11 days. Samples of eggs and meat from the laying hens were collected. Egg yolks and albumen were separated. Meat was collected from the breast and femur. The metabolic products of CCC were measured using ion trap electrospray ionisation mass spectrometry (ion trap-ESI-MS/MS). Determination of CCC or its metabolites in eggs and meat showed that CCC was metabolised to choline. Corresponding MS/MS spectra were obtained for m/z 104 (choline) or 105 ((15)N-choline), whereas nothing was detected at m/z 122 (CCC) or 123 ((15)N-CCC). The results from this study indicate that CCC will be metabolised in tissues of laying hens.     

Echinococcus multilocularis in Austrian foxes from 1991 until 2004

The prevalence rates of Echinococcus multilocularis in foxes (n=5600) evaluated in several Austrian surveys conducted between 1991 and 2004 were analysed for spatial and temporal differences. Data from early studies (1993-1997) in which the intestinal scraping technique (IST) was utilized were compared with data from recent (1999-2004) investigations, which made use of the shaking in a vessel technique (SVT), and it was assessed whether or not the infection rates of Austrian foxes had increased between the investigated intervals. In total, data from 85 districts are presented and both the retrospective and recent data are available from 39 of these districts. A Bayesian hierarchical model of parasite prevalences is presented which (i) accounts for differences in the sensitivity of IST and SVT, (ii) incorporates spatial auto-correlation between neighbouring districts, (iii) investigates the possibility of a temporal shift in the infection status of foxes, and (iv) quantifies uncertainty at each level of the model. The national average prevalence rates in the mid-1990s and at the turn of the millennium were 2.4% (95% confidence intervals 1.1-4.8) and 3.9% (95% confidence intervals 1.5-8.4) respectively. Above average prevalence rates were observed in the western and the northern parts of the country. Evidence is also presented for a temporal augmentation of the prevalence rates in some districts in the northern and eastern parts of the country. These findings are in concordance with several investigations in other European states where both newly emerged areas and elevated levels of transmission in existing endemic areas have been found. None of the districts investigated here showed significant evidence of a drop in prevalence.     

The new E.U. Animal Transport Regulation: improved welfare and health or increased administration?

There is public discussion of the new E.U. Animal Transport Regulation No 1/2005 of Dec. 2004 and its advantages and draw-backs. This Regulation is no longer a Directive, so that it is directly applicable in the Members States. Although the Regulation is recognised to have great potential to improve welfare and health of transported animals, it will also increase administrative work. Most improvements will come through better education and the increased responsibilities of animal attendants, drivers, keepers and transport organisers, and through the stricter control mechanisms (log book, training, instructions etc.) and the introduction of the GPS control systems to further enhance the transparency of animal movements. The formats of the transport certificates used in all Member States will be harmonised. Technical records will be kept on air temperature and water consumption. Contact offices in all member states for transport affairs will improve the exchange of data between the responsible authorities and harmonise control and surveillance practice. Specific regulations are now in place for horses (broken, unbroken, registered) and for the transport age of young animals (piglets, lambs, calves, foals). In spite of some substantial improvements there are still significant gaps in our knowledge of both normal and long transports, for example optimal journey times, food and water supply on long transports, environmental factors such as vibration, motion, light and ventilation requirements in different European geographical regions. The same is true for the epidemiological aspects of the prevention of disease transmission; for example, very little is known about the bacterial and particulate emissions of the animal transport vehicles which travel across Europe. A serious drawback of the regulation is the fact that it does not abolish the unloading of animals on long transports to rest for 24 h at staging points, so that the concomitant risks to health and welfare remain, as do the opportunities for the transmission of infectious diseases at these stations. Two examples are given that demonstrate the physiological (heart rate) and biochemical (cortisol) reactions of cattle during transport. It seems useful to observe how the new Regulation affects practice and to assess the usefulness and practicability of the new rules after one or two years of operation. At the same time, more detailed research should be carried out in order to further adapt the Regulation to the needs of the animal species and gender in terms of travel time periods, food supply and resting schemes. This should also include reconsideration of loading and unloading rules in staging points on long journeys for all animals, particularly in view of risks of injury and transmission of infectious diseases. Investigations should be carried out to improve our understanding of the bio-aerosol emissions from driving and standing vehicles. Transport schemes on long journeys should be more closely adapted to the needs of the animals. The new Regulation represents another step forward toward improved animal welfare during transport in spite of some increase in the administrative measures required. It is necessary to bring together veterinary and animal science, engineering, logistics and practical and technical experience in order to improve the Regulation and the health and welfare of animals during transport.     

Syringomyelia: current concepts in pathogenesis, diagnosis, and treatment

Syringomyelia is a condition that results in fluid-containing cavities within the parenchyma of the spinal cord as a consequence of altered cerebrospinal fluid dynamics. This review discusses the history and the classification of the disorder, the current theories of pathogenesis, and the advanced imaging modalities used in the diagnosis. The intramedullary pulse pressure theory (a new pathophysiologic concept of syringomyelia) also is presented. In addition, the current understanding of the painful nature of this condition is discussed and the current trends in medical and surgical management are reviewed.     

Sex steroids level in blood plasma and ovarian follicles of the chimeric chicken

The study was performed to determine the hormonal status of mature germline chimeras obtained by blastodermal cell transfer from chicken embryos of a donor breed [Green-legged Partridgelike breed (GP) x Araucana (AR)] to those of a recipient breed [White Leghorn (WL)] being at the same stage of embryonic development. The egg-laying chimeras and WL hens (control) of the same age were used in the experiment. At first, blood samples were taken from each bird at 0.5, 5, 12.5 and 18.5 h following oviposition. Subsequently, the chimeras and the WL hens were decapitated 1-2 h after ovulation. A stroma and the following follicles were isolated from the ovary: white normal (1-4, 4-6 and 6-8 mm), white atretic and yellow preovulatory follicles (F4-F1). Sex hormones, progesterone (P4), testosterone (T) and oestradiol (E2) in blood plasma and ovarian follicles were determined radioimmunologically. The activity of the 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the granulosa and theca layers of the follicles was analysed histochemically. In chimeric chickens, a higher level of T in blood plasma during the ovulatory cycle was noticed. However, in the stroma, white prehierarchical and medium-size preovulatory ovarian follicles the level of T was significantly lower. With respect to E2, its elevated levels were found both in blood and in the ovarian follicles. There were no significant differences in P4 concentrations in blood plasma while in ovarian follicles a higher level was observed only in white 6-8 mm follicles. 3beta-HSD activity in granulosa and theca layers of the ovarian follicles in chimeras was not different from that in the WL hens. In conclusion, the results obtained indicate that germline chimeras exhibit significant alterations in sex hormone levels in the ovary and blood plasma, which in turn may affect their reproductive abilities.     

Maintenance of body temperature in the neonatal lamb: effects of breed, birth weight, and litter size

To survive, the newborn lamb must be able to maintain body temperature and to stand and move to the udder to suck colostrum to fuel heat production. The objective of this study was to investigate whether neonatal lambs showing slow behavioral progress to standing and sucking also have an impaired ability to maintain body temperature. The time taken to stand and suck after birth, rectal temperatures, and blood samples were collected from 115 newborn single, twin, and triplet lambs of 2 breeds, Scottish Blackface and Suffolk, which are known to show variations in their neonatal behavioral progress. Blood samples were assayed for thyroid hormones, known to be involved in heat production, and cortisol, which plays a role in tissue maturation before birth. In addition, colostrum samples were collected from the 56 ewes that gave birth to the lambs, and assayed for protein, fat, and vitamin contents. Heavy lambs (more than 1 SD above the breed mean), Blackface lambs, and singleton or twin lambs were quicker to stand and suck from their mothers than lightweight (more than 1 SD below the breed mean), Suffolk, or triplet lambs. Low birth weight lambs also had lower rectal temperatures than heavier lambs (P < 0.01), as did Suffolk compared with Blackface lambs (P < 0.001). Lambs that were slow to suck after birth had lower rectal temperatures than quick lambs, and this difference persisted for at least 3 d after birth. Within breed, heavy lambs had greater plasma triiodothyronine and thyroxine immediately after birth than light lambs. Blackface lambs had greater plasma triiodothyronine and thyroxine than Suffolk lambs but tended to have less cortisol. Colostrum produced by Blackface ewes had a greater fat content than that of Suffolk ewes (P < 0.001). Thus, lambs that are behaviorally slow at birth are also less able to maintain their body temperature after birth. Although part of their lower body temperature might be attributable to behavioral influences on thermoregulation, the data also suggest that physiological differences exist between these animals. These differences may be related to different degrees of maturity at birth.