Bryan Iotti

In vitro description of a new technique for stapled side-to-side jejunocecal anastomosis in horses and CT scan anatomical comparison with other techniques

BackgroundStapled jejunocecal anastomoses are commonly performed in equine abdominal surgery. They carry higher complication rates compared to handsewn techniques. In human surgery various causes likely to lead to failure of stapled techniques have been evaluated, including staple line failure. Recently Freeman proposed a technique to perform a stapled jejunocecal anastomosis in horses while avoiding blind pouch formation. The aim of this study is to describe a method for stapled side-to-side jejunocecal anastomosis in horses and to compare it with other techniques with computed tomography to assess stomal area, shape and blind pouch size.MethodsIntestinal specimens comprising the cecum, ileum and jejunum from 18 horses were collected and were divided into three groups. In Group S a standard stapled side-to-side jejunocecal anastomosis was performed. In Group F the anastomosis was performed using a modified technique proposed by Freeman. In Group G the anastomosis was performed with a modified technique proposed by the authors. Inflated bowel segments were CT scanned to obtain a MultiPlanar Reconstruction of the stoma and afferent small intestine before calculating the cross-sectional area of each of these regions. The ratio of the measured areas was compared between the three techniques. The volume of the blind-end pouch was measured and its ratio with the intestinal area compared between techniques. The cecum was opened and the length of the stoma measured with a caliper and compared to the intended initial length.ResultsThe stomal/intestinal area ratio was not significantly different between techniques.No statistically significant difference was found in the stomal ideal/real perimeter ratio.There was no statistically significant difference in the intended/real stomal length ratio, and all techniques featured an increase in stomal length ranging from 2 to 12 %. Blind pouch formation was a consistent finding in Group S and was virtually absent in Groups F and G.ConclusionsBoth the Freeman and the new (G) technique were comparable to the standard technique in terms of stomal area, stomal shape and difference in stomal elongation. They consistently produced a smaller blind pouch and allowed easier placement of the staplers.

Biomechanical comparison of four technique for pelvic flexure enterotomy closure in horses

OBJECTIVE To compare 4 techniques for pelvic flexure enterotomy closure in horses. STUDY DESIGN Ex-vivo study. SAMPLE POPULATION Cadaveric ascending colon specimens (n = 48 horses). METHODS Pelvic flexure enterotomies of different lengths (5 cm, 10 cm) were performed and closed with 1 of 4 techniques: handsewn 2 layer (HS2); handsewn 1 layer (HS1); skin staples (SKS); or TA90 stapling device (TA90). Time to close each enterotomy, bursting pressure, luminal reduction, and cost were calculated and compared. RESULTS HS2 was significantly more time consuming to perform in the 5 cm group whereas in the 10 cm group, only the HS1 and SKS were faster than the other techniques. Luminal reduction was not different between techniques in either group. HS2 resulted in consistently higher bursting pressure compared with SKS and TA90 in the 5 cm group and compared to all other techniques in the 10 cm group. CONCLUSION The TA90 technique had the lowest bursting pressure and highest cost. The HS2 technique was strongest.Objective To compare 4 techniques for pelvic flexure enterotomy closure in horses. Study Design Ex-vivo study. Sample Population Cadaveric ascending colon specimens (n = 48 horses). Methods Pelvic flexure enterotomies of different lengths (5 cm, 10 cm) were performed and closed with 1 of 4 techniques: handsewn 2 layer (HS2); handsewn 1 layer (HS1); skin staples (SKS); or TA90 stapling device (TA90). Time to close each enterotomy, bursting pressure, luminal reduction, and cost were calculated and compared. Results HS2 was significantly more time consuming to perform in the 5 cm group whereas in the 10 cm group, only the HS1 and SKS were faster than the other techniques. Luminal reduction was not different between techniques in either group. HS2 resulted in consistently higher bursting pressure compared with SKS and TA90 in the 5 cm group and compared to all other techniques in the 10 cm group. Conclusion The TA90 technique had the lowest bursting pressure and highest cost. The HS2 technique was strongest.

Pestivirus infection in cattle dairy farms: E2 glycoprotein ELISA reveals the presence of bovine viral diarrhea virus type 2 in northwestern Italy

BackgroundBovine viral diarrhea virus (BVDV) types 1 and 2 are members of the Pestivirus genus of the Flaviviridae family. This genus also includes the HoBi-like virus, tentatively classified as BVDV type 3. BVDV-1 is widely distributed in Italy despite the extensive use of BVDV-1-based vaccines, while BVDV-2 and HoBi-like Pestivirus have been detected occasionally. Monitoring the occurrence of sporadic or atypical pestiviruses is a useful approach to evaluate the need for additional vaccine strains that can be used in BVDV control programs.ResultsIn this study we developed a multiwell antibody ELISA based on the recombinant E2 protein of the three bovine pestiviruses. We evaluated the assay’s applicability for surveillance purposes using pooled milk samples, each prepared from a maximum of 35 lactating cows and collected from 176 dairy herds. As expected, the majority of the pooled samples reacted to a greater extent against the BVDV-1 E2 antigen. All three milk pools from a single farm reacted to the BVDV-2 antigen, however. Further analysis using spot tests, antigen detection, and sequence analysis of the 5′-UTR region confirmed the presence of five persistently infected calves carrying a BVDV-2a strain.ConclusionsThis study highlights for the first time that sporadic circulation of BVDV-2 can be predicted by immunoenzymatic methods in the absence of specific vaccination.

Surveillance of Infectious Bovine Rhinotracheitis in marker-vaccinated dairy herds: Application of a recombinant gE ELISA on bulk milk samples

Infectious Bovine Rhinotracheitis (IBR) occurs worldwide, requiring significant resources for eradication programs or surveillance purposes. The status of infection is usually detected by serological methods using the virus neutralization test (VNT) or enzyme-linked immunosorbent assay (ELISA) on individual sera. The gE DIVA (Differentiating Infected from Vaccinated Animals) vaccines approach, adopted in order to reduce the virus circulation and prevent clinical signs, have tightened the range of available methods for the serological diagnosis. Different gE blocking ELISA could be performed to detect specific antibodies in sera of infected or whole virus-vaccinated animals but with less sensitivity if applied to bulk milk samples, especially in marker-vaccinated herds. A new rec-gE ELISA was recently developed in Italy and applied with good performances on blood serum samples. The present paper focuses on the application of a rapid protocol for purification/concentration of immunoglobulin G (IgG) from bulk milk and on the use of the new rec-gE indirect ELISA. The study involved three different partners and 225 herds (12,800 lactating cows) with different official IBR diagnostic statuses. The diagnostic specificity of the method was demonstrated closed to 100% while the diagnostic sensitivity was strictly related to the herd-seroprevalence. Considering 2.5% as the limit of detection of within-herd seropositivity prevalence, the diagnostic sensitivity showed by the proposed method was equal to 100%. A single reactivation of a whole strain vaccine in an old cow was detected inside a group of 67 lactating cows, showing the field applicability of the method.

Infection dynamics on spatial small-world network models

The study of complex networks, and in particular of social networks, has mostly concentrated on relational networks, abstracting the distance between nodes. Spatial networks are, however, extremely relevant in our daily lives, and a large body of research exists to show that the distances between nodes greatly influence the cost and probability of establishing and maintaining a link. A random geometric graph (RGG) is the main type of synthetic network model used to mimic the statistical properties and behavior of many social networks. We propose a model, called REDS, that extends energy-constrained RGGs to account for the synergic effect of sharing the cost of a link with our neighbors, as is observed in real relational networks. We apply both the standard Watts-Strogatz rewiring procedure and another method that conserves the degree distribution of the network. The second technique was developed to eliminate unwanted forms of spatial correlation between the degree of nodes that are affected by rewiring, limiting the effect on other properties such as clustering and assortativity. We analyze both the statistical properties of these two network types and their epidemiological behavior when used as a substrate for a standard susceptible-infected-susceptible compartmental model. We consider and discuss the differences in properties and behavior between RGGs and REDS as rewiring increases and as infection parameters are changed. We report considerable differences both between the network types and, in the case of REDS, between the two rewiring schemes. We conclude that REDS represent, with the application of these rewiring mechanisms, extremely useful and interesting tools in the study of social and epidemiological phenomena in synthetic complex networks.

Ex Vivo Anatomical Characterization of Handsewn or Stapled Jejunocecal Anastomosis in Horses by Computed Tomography Scan

The aim of this study is to compare handsewn and stapled jejunocecal anastomosis with different stomal lengths in terms of anatomical differences. Group 1 underwent a two-layer handsewn jejunocecal side-to-side anastomosis (HS); Group 2 received a stapled jejunocecal side-to-side anastomosis (GIA). Each group was divided into two subgroups (HS80 and HS100, GIA80 and GIA100). Specimens were inflated and CT scanned. The stomal/jejunal area ratio and blind end pouch volume/area were measured and compared. Effective length of the stoma was measured and compared with the initial length. Stomal/jejunal area ratio was 1.1 for both 80 techniques, 1.6 for the GIA100, and 1.9 for the HS100 technique. Both HS and GIA techniques produced a blind end pouch and exhibited a mean increase of the final stomal length ranging from 6 to 11% greater than the original stomal length. All techniques will exhibit a length increase of the final stomal length compared to the intended stomal length, with a consequent increase in stomal area. Stapled techniques consistently produced a large distal blind end pouch. Length of a jejunocecal anastomosis should be selected in accordance with the diameter of afferent jejunum, and the 80 mm stomal length could be deemed sufficient in horses.

Farm productive realities and the dynamics of bovine viral diarrhea (BVD) transmission

Bovine Viral Diarrhea (BVD) is a viral disease that affects cattle and that is endemic to many European countries. It has a markedly negative impact on the economy, through reduced milk production, abortions, and a shorter lifespan of the infected animals. Cows becoming infected during gestation may give birth to Persistently Infected (PI) calves, which remain highly infective throughout their life, due to the lack of immune response to the virus. As a result, they are the key driver of the persistence of the disease both at herd scale, and at the national level. In the latter case, the trade-driven movements of PIs, or gestating cows carrying PIs, are responsible for the spatial dispersion of BVD. Past modeling approaches to BVD transmission have either focused on within-herd or between-herd transmission. A comprehensive portrayal, however, targeting both the generation of PIs within a herd, and their displacement throughout the Country due to trade transactions, is still missing. We overcome this by designing a multiscale metapopulation model of the spatial transmission of BVD, accounting for both within-herd infection dynamics, and its spatial dispersion. We focus on Italy, a country where BVD is endemic and seroprevalence is very high. By integrating simple within-herd dynamics of PI generation, and the highly-resolved cattle movement dataset available, our model requires minimal arbitrary assumptions on its parameterization. Notwithstanding, it accurately captures the dynamics of the BVD epidemic, as demonstrated by the comparison with available prevalence data. We use our model to study the role of the different productive realities of the Italian market, and test possible intervention strategies aimed at prevalence reduction. We find that dairy farms are the main drivers of BVD persistence in Italy, and any control strategy targeting these farms would lead to significantly higher prevalence reduction, with respect to targeting other production compartments. Our multiscale metapopulation model is a simple yet effective tool for studying BVD dispersion and persistence at country level, and is a good instrument for testing targeted strategies aimed at the containment or elimination of this disease. Furthermore, it can readily be applied to any national market for which cattle movement data is available.

Contagion on Networks with Self-Organised Community Structure

Living systems are organised in space. This imposes constraints on both their structural form and, consequently, their dynamics. While artificial life research has demonstrated that embedding an adaptive system in space tends to have a significant impact on its behaviour, we do not yet have a full account of the relevance of spatiality to living self-organisation. Here, we extend the REDS model of spatial networks with self-organised community structure to include the “small world” effect. We demonstrate that REDS networks can become small worlds with the introduction of a small amount of random rewiring. We then explore how this rewiring influences a simple dynamic process representing the contagious spread of infection or information. We show that epidemic outbreaks arise more easily and spread faster on REDS networks compared to standard random geometric graphs (RGGs). Outbreaks spread even faster on randomly rewired small world REDS networks (due to their shorter path lengths) but initially find it more difficult to establish themselves (due to their reduced community structure). Overall, we find that small world REDS networks, with their combination of short characteristic path length, positive assortativity, strong community structure and high clustering, are more susceptible to a range of contagion dynamics than RGGs, and that they offer a useful abstract model for studying dynamics on spatially organised organic systems.

Biomechanical comparison of four technique for pelvic flexure enterotomy closure in horses: Pelvic Flexure Enterotomy Closure

OBJECTIVE To compare 4 techniques for pelvic flexure enterotomy closure in horses. STUDY DESIGN Ex-vivo study. SAMPLE POPULATION Cadaveric ascending colon specimens (n = 48 horses). METHODS Pelvic flexure enterotomies of different lengths (5 cm, 10 cm) were performed and closed with 1 of 4 techniques: handsewn 2 layer (HS2); handsewn 1 layer (HS1); skin staples (SKS); or TA90 stapling device (TA90). Time to close each enterotomy, bursting pressure, luminal reduction, and cost were calculated and compared. RESULTS HS2 was significantly more time consuming to perform in the 5 cm group whereas in the 10 cm group, only the HS1 and SKS were faster than the other techniques. Luminal reduction was not different between techniques in either group. HS2 resulted in consistently higher bursting pressure compared with SKS and TA90 in the 5 cm group and compared to all other techniques in the 10 cm group. CONCLUSION The TA90 technique had the lowest bursting pressure and highest cost. The HS2 technique was strongest.Objective To compare 4 techniques for pelvic flexure enterotomy closure in horses. Study Design Ex-vivo study. Sample Population Cadaveric ascending colon specimens (n = 48 horses). Methods Pelvic flexure enterotomies of different lengths (5 cm, 10 cm) were performed and closed with 1 of 4 techniques: handsewn 2 layer (HS2); handsewn 1 layer (HS1); skin staples (SKS); or TA90 stapling device (TA90). Time to close each enterotomy, bursting pressure, luminal reduction, and cost were calculated and compared. Results HS2 was significantly more time consuming to perform in the 5 cm group whereas in the 10 cm group, only the HS1 and SKS were faster than the other techniques. Luminal reduction was not different between techniques in either group. HS2 resulted in consistently higher bursting pressure compared with SKS and TA90 in the 5 cm group and compared to all other techniques in the 10 cm group. Conclusion The TA90 technique had the lowest bursting pressure and highest cost. The HS2 technique was strongest.