Leukocyte endothelial cell interactions in pig to human organ xenograft rejection

In cases where antibody- and complement-mediated hyperacute rejection (HAR) of vascularized organ xenografts has been prevented, acute vascular rejection (AVR) and acute T cell-mediated rejection (ACR) cause graft destruction. Infiltration of leukocytes (innate and graft-primed T cells) into the graft execute the latter two rejection modalities. The leukocyte extravasation process, which is a prerequisite for graft infiltration, is governed by adhesion molecules, including the selectin, integrin and immunoglobulin protein families, and the chemokine protein family. The compatibility between porcine endothelial cell and human leukocyte adhesion molecules was investigated in dynamic adhesion and static transendothelial migration assays. The effect of human anti-pig antibodies on human leukocyte adhesion to, and transendothelial migration across, porcine endothelium was assessed under dynamic and static conditions, respectively. In contrast to previously published results, no difference in the ability of neutrophils to adhere to pig and human endothelium was observed. Furthermore, no evident quantitative or qualitative differences in the capacity of human and porcine endothelium to support transendothelial migration of human leukocytes (T, B and natural killer (NK) cells, monocytes, and neutrophils) could be detected. The presence of human anti-pig antibodies (Abs) modulated the migration of leukocytes across porcine endothelium, as well as neutrophil adhesion to porcine endothelium under conditions of flow. Antibodies specific for pig endothelial adhesion molecules can potentially be used as species (graft)-specific immunosuppressive reagents in order to prevent cellular organ xenograft rejection.     

Seroepidemiology of beef and dairy herds and fetal study of Neospora caninum in Argentina

The purpose of the present work was to study the epidemiology of Neospora caninum in beef and dairy herds in the Humid Pampas of Argentina. The seroprevalence of N. caninum was evaluated in 2414 serum samples of cows from beef and dairy farms. An indirect fluorescent antibody test (IFAT) was used to determine specific antibodies. The sera was screened at a dilution >or=1:200 and >or=1:600 in cows with reproductive disease antecedents and without them, respectively. Cows without history of reproductive diseases from nine beef and fifteen dairy farms were grouped according to the percentage (> or or 相似文献   

Efficacy of Hypovirulent Binucleate Rhizoctonia sp. to Control Banded Leaf and Sheath Blight in Corn

Water agar, artificially infested soil and leaf sheath inoculation methods were used to assess the suitable time of application, varietal host response and persistence of Rhv7, a hypovirulent, binucleate Rhizoctonia collected from soil in the Philippines, to effectively control virulent Rhizoctonia solani AG1-IA isolate RS35 on corn. With the water agar method, prior inoculation (2 to 3 days) with the biocontrol agent is essential to achieve maximum control of the pathogen. Disease protection was increased from 23 to 70% as the pre-incubation time of Rhv7 prior to the challenge inoculation with virulent isolate was lengthened from 0 to 3 days. Disease severity and incidence of banded leaf and sheath blight (BLSB) on the three corn hybrids were also suppressed in artificially infested soil. In leaf sheath inoculation, the suppressive ability of Rhv7 against BLSB on corn persisted during lesion expansion. This suppression was expressed as slower disease progress in plants with Rhv7 than in plants without Rhv7. Early and timely brace root formation that detached infected sheaths, also aided in reducing the number of diseased plants in Rhv7-treated plots at the final observation. Mycelial growth activity of RS35 was reduced when corn plants were pre-inoculated with Rhv7 before challenge even if there was no contact detected between Rhv7 and RS35, which suggests that Rhv7 protects corn against BLSB by induced resistance. The hypovirulent, binucleate Rhizoctonia Rhv7 strain effectively controlled R. solani AG1-IA isolate RS-35 in corn. Received 30 August 1990/ Accepted in revised form 25 October 1999     

The Bovine Tuberculosis Campaign in Mexico： Present and Perspectives

Mexico is considered by different international organizations as a country where the bovine tuberculosis is an endemic problem. However, there are important and consistent improvements in eradicating the disease by the implementation of government policies and with the livestock organization support. The current situation of the program shows good results regarding decreasing the prevalence, and as a consequence, the risk of this disease for public health and animal health, as well as the improvement in animal production and international and national trade. Today, the bovine tuberculosis distribution is almost known in Mexico. In addition, a series of controls and indicators have been established, which allow maintain consistency and reliability in the data that are managed and analyzed.     

Astrovirus as a possible cause of congenital tremor type AII in piglets?

Background

Congenital tremor is associated with demyelination of the brain and spinal cord and is clinically noted as outbreaks of trembling and shaking in newborn piglets during a limited time-period. Six forms of the disease have been described, where form AII may be caused by an, as yet, unidentified viral infection. This study aimed to investigate the presence of astrovirus and circovirus by sequencing and polymerase chain reaction (PCR) analysis and by relating the findings to the occurrence of disease and lesions in the brain, in 4–6 days-old piglets obtained from a clinical outbreak of congenital tremor.

Results

In piglets with congenital tremor, there were mild to moderate vacuolar changes of the white matter in the cerebrum, brain stem and cerebellum. In healthy piglets, less conspicuous vacuolar changes were detected. One healthy and one diseased piglet were positive for porcine circovirus type 2. The nested pan-PCR showed the presence of astrovirus in at least one brain region in all piglets and by sequencing, two different porcine astrovirus lineages were identified.

Conclusions

The results do not support previous studies identifying porcine circovirus type 2 as the cause of congenital tremor. The demonstration of astrovirus in the brain of piglets suffering from congenital tremor is interesting. However, astrovirus was demonstrated in both healthy and diseased individuals and therefore, further studies are warranted to determine the possible involvement of astrovirus in the pathogenesis of congenital tremor in pigs.     

Neospora caninum is a cause of perinatal mortality in axis deer (Axis axis)

Neospora caninum is a worldwide distributed protozoan that may cause neuromuscular disease in dogs and reproductive failure in domestic and wild ruminants. One axis fawn (Axis axis) and four neonates from the same deer herd died at a zoo in Argentina within a four-month period. The fawn presented with dilatation of the anal sphincter at birth and incontinence, developed weakness and ataxia and died at 14 days of age. At necropsy, a mega formation of the distal large intestine was observed. Microscopically, non-suppurative encephalitis, suppurative bronchopneumonia, fibrin necrotic enteritis and degenerative changes in the liver were observed in hematoxilin and eosin-stained tissue sections, and thick-walled N. caninum-like cysts were observed in fresh brain samples. Serologic studies for N. caninum revealed an IFAT titer of 1:6400 in the fawn and 1:25, 1:400, 1:3200 and 1:6400 in the neonates. N. caninum DNA was detected in brain samples from the fawn and from one neonate by PCR, and the parasite was isolated in vitro from the fawn’ brain after passage through gerbils (Meriones unguiculatus) and gamma-interferon knock-out mice. N. caninum DNA obtained from the fawn, neonate and isolated parasites showed the same microsatellite pattern. This suggests a common infection source for both animals.The diagnosis of N. caninum infection was confirmed, suggesting its association with perinatal mortality in captive axis deer. To the best of our knowledge, this is the first report of clinical disease associated to N. caninum infection in axis deer and of isolation of the parasite from this wild ruminant species.     

Identification of a universal Group B streptococcus vaccine by multiple genome screen

Group B Streptococcus (GBS) is a multiserotype bacterial pathogen representing a major cause of life-threatening infections in newborns. To develop a broadly protective vaccine, we analyzed the genome sequences of eight GBS isolates and cloned and tested 312 surface proteins as vaccines. Four proteins elicited protection in mice, and their combination proved highly protective against a large panel of strains, including all circulating serotypes. Protection also correlated with antigen accessibility on the bacterial surface and with the induction of opsonophagocytic antibodies. Multigenome analysis and screening described here represent a powerful strategy for identifying potential vaccine candidates against highly variable pathogens.     

The effect of dietary supplementation with globin and spray-dried porcine plasma on performance,digestibility and histomorphological traits in broiler chickens

This study evaluated the effects of globin and spray-dried porcine plasma (SDPP) on growth performance, digestibility, nitrogen retention, energy retention efficiency (ERE) and intestinal morphology of broiler chickens. A total of 336-day-old male broiler chickens were reared from 1 to 40 days of age and fed 3 diets (8 replicates/diet, 14 birds/replicate) during 3 feeding phases: starter (1–12 days), grower (12–25 days) and finisher (25–40 days). Isonitrogenous diets were formulated by replacing gluten protein isolate contained in the control diet (C diet) with 2% (starter) or 1% (grower and finisher) spray-dried porcine plasma in the plasma diet (SDPP diet). The globin diet (G diet) was obtained by adding globin on the top of C diet at a dose of 0.08% for the whole rearing period. Total tract apparent digestibility (aD), nitrogen retention and ERE were assessed during the three growing phases. At 12  and 40 days of age, one bird per pen was slaughtered to sample gut, liver, spleen and bursa of Fabricius for histomorphological investigations. The SDPP diet increased body weights of chickens at 12 (+60 g; p < .001), 25 (+101 g; p < .001) and 40 days (+130 g; p = .018) of age compared to C and G diets. Also SDPP improved crude protein aD (+9.7%) and ERE (+12.3%) during the starter phase (p < .001). Dietary globin and SDPP inclusion did not affect either the gut morphology or the histopathological findings in birds at 12 and 40 days of age, despite a numerical (+6.90% and +7.40% respectively) villus height improvement in the SDPP group. Overall, these results confirm that dietary supplementation with SDPP and, to a lesser extent, with globin can improve growth performance and dietary protein and energy utilization in broiler chickens without effect on gut functionality.