Marjan Doom

Immunopathological mechanisms in dogs with rupture of the cranial cruciate ligament

The majority of studies on cranial cruciate ligament (CrCL) disease to date have been carried out on dogs that already sustained a CrCL rupture, which is the end-stage of the disease. Investigations have recently been carried out to study humoral and cellular immunopathological mechanisms in predisposed dogs before clinical rupture of the contralateral CrCL. The cruciate ligaments are mainly composed of collagen type I, and immune responses to collagen have been suggested as a cause of CrCL degradation in dogs. None of these investigations showed evidence that anticollagen type I antibodies alone initiate CrCL damage. However, in predisposed dogs a distinct anticollagen type I antibody gradient was found towards the contralateral stifle joint that eventually sustained a CrCL rupture, suggesting that there was an inflammatory process present in these joints before detectable joint instability occurred. The importance of cellular reactivity to collagen type I in cruciate disease also remains unclear. Peripheral blood mononuclear cell proliferation to collagen type I was very diverse in dogs with cruciate disease whereas some sham operated dogs and healthy dogs tested positive as well. It is not yet determined whether cellular reactivity to collagen type I exists locally in the stifle joints nor whether this could initiate CrCL degradation. Inflammatory processes within the stifle joint can alter the composition of the cruciate ligaments. In animal models of immune-mediated synovitis, the mechanical strength of the CrCL is significantly reduced. Immunohistochemical studies on synovial tissues from dogs with rheumatoid arthritis and dogs with cruciate disease revealed that the pathologic features are similar in both joint pathologies and that the differences are mainly quantitative. Joint inflammation induced by biochemical factors such as cytokines has been implied in CrCL degeneration. In several studies, the levels of pro-inflammatory and T helper cytokines were measured in dogs that sustained a CrCL rupture, but the exact role of the various cytokines in the pathogenesis of CrCL disease remains inconclusive. More recently, the levels of the cytokines have been investigated over time in predisposed dogs before and after CrCL rupture. IL-8 expression tended to be higher in stifle joints that will rupture their CrCL during the next 6 months than in those that will not, indicating an inflammatory process in these joints before clinical rupture. This review provides a comprehensive overview of all possible implications of humoral and cell-mediated immune responses published in dogs with cruciate disease together with publications from human joint diseases. Furthermore, this review highlights recent findings on cytokines and proteinases in the accompanying joint inflammation.

Locations of gut-associated lymphoid tissue in the 3-month-old chicken: a review.

The lymphoid tissue that is associated with the intestinal tract, the so-called gut-associated lymphoid tissue (GALT), is well developed in the chicken. Depending on the location, it is present as aggregations of lymphoid cells, or organized in lymphoid follicles and tonsils. From proximal to distal, the intestinal tract contains a pharyngeal tonsil, diffuse lymphoid tissue and lymphoid follicles in the cervical and thoracic parts of the oesophagus, an oesophageal tonsil, diffuse lymphoid tissue in the proventriculus, a pyloric tonsil, Peyers patches, Meckels diverticulum, two caecal tonsils, diffuse lymphoid tissue in the rectum, the bursa of Fabricius, and diffuse lymphoid tissue in the wall of the proctodeum. The lymphoid tissues are frequently covered by a lympho-epithelium that is infiltrated by lymphoid cells. Such an epithelium often contains M or microfold cells, which are specialized in antigen sampling and transport antigens to the underlying lymphoid tissue. A solid knowledge of the avian GALT could contribute to the development of vaccines to be administered orally. Additionally, immune stimulation via pre- and probiotics is based on the presence of a well-developed intestinal immune system.

The accuracy of the Lactate Pro hand-held analyser to determine blood lactate in healthy dogs

OBJECTIVES The objective of this study was to determine the accuracy of the Lactate Pro hand-held analyser in measuring blood lactate levels. METHODS Blood was drawn from 15 healthy dogs into five tubes containing Na-EDTA. Lactate was measured immediately using the Lactate Pro analyser and a laboratory reference method. Further samples were analysed 120, 240, 480 and 1440 minutes later to artificially increase the lactate levels. Lactate was measured in blood samples of 60 healthy dogs using the Lactate Pro analyser to determine the reference interval of lactate concentration in normal dogs. RESULTS The correlation between the lactate concentration measured with the Lactate Pro analyser and the reference method was high. Lactate levels were lower when measured with the hand-held analyser than with the traditional laboratory determination. The reference interval for blood lactate concentrations in healthy dogs established by the Lactate Pro analyser was from the detection limit (0.8 mmol/l) up to 3.3 mmol/l. CLINICAL SIGNIFICANCE The Lactate Pro analyser provides quick and reliable measurements of blood lactate in dogs with blood lactate levels up to 10 mmol/l. Because of its small sample size, this analyser will be particularly appropriate for use in small animal intensive care.

The pulmonary veins of the pig as an anatomical model for the development of a new treatment for atrial fibrillation.

The layout of the porcine atriopulmonary junction and immediately adjacent structures was investigated by gross anatomical and vascular corrosion casting studies to meet the need for more in‐depth anatomical insights when using the pig as an animal model in the development of innovative approaches for surgical cardiac ablation in man. The veins from the right cranial and middle lung lobes drain through a common ostium in the left atrium, whereas a second ostium receives the blood returning from all other lung lobes, although limited variation to this pattern was observed. Surrounding anatomical structures that are most vulnerable to ablation damage as reported in man are located at a safer distance from the pulmonary veins in pigs, yet a certain locations, comparable risks are to be considered. Additionally, it was histologically confirmed that myocardial sleeves extend to over a centimetre in the wall of the pulmonary veins.

Effects of medetomidine and ketamine on the regional cerebral blood flow in cats: A SPECT study

Brain perfusion can be investigated using single photon emission computed tomography (SPECT) and the intravenous injection of (99m)technetium ethyl cysteinate dimer ((99m)Tc-ECD). However, sedation using medetomidine, an α(2)-agonist, or anaesthesia using medetomidine and ketamine, an N-methyl-d-aspartate-(NMDA)-antagonist, may be required for SPECT studies in cats but can affect the regional cerebral blood flow (rCBF). The effects of medetomidine, with or without ketamine, on regional brain perfusion were therefore investigated in six cats under three conditions. Injection of tracer occurred before sedation or anaesthesia (condition A), following intramuscular (IM) sedation with medetomidine (condition M) or after IM anaesthesia with medetomidine and ketamine (condition MK). Medetomidine and medetomidine with ketamine caused a significantly higher total tracer uptake in all brain regions. Semi-quantification of brain perfusion gave lower perfusion indices in several sub-cortical regions in conditions M and MK, compared to A. Left-right differences were observed in the temporal cortex (A), the temporal, parietal cortex and the thalamus (M) and the frontal cortex (MK). A significantly higher perfusion index in the sub-cortical regions, compared to the whole cortex, was only present in condition A. This study showed that caution is needed when quantifying brain perfusion indices when using sedative or anaesthetic agents that may affect rCBF.

A topographic anatomical study of the equine epiploic foramen and comparison with laparoscopic visualisation.

REASONS FOR PERFORMING STUDY There are no previous studies correlating the anatomy of the equine epiploic foramen and its defining structures with laparoscopic images. OBJECTIVES The purpose of this study was to describe the precise anatomy of the epiploic foramen and omental vestibule, to quantify the dimensions of the epiploic foramen and to relate these findings to laparoscopic images. STUDY DESIGN Descriptive study of cadaver material and laparoscopic images. METHODS Thirty-two horses subjected to euthanasia for reasons unrelated to colic were studied. Two cadavers were used to make vascular casts of the coeliac artery and portal vein. In 30 cadavers the epiploic foramen and omental vestibule were cast with a polyurethane prepolymer immediately after euthanasia. The cast served as a landmark during dissection and the circumference of the epiploic foramen was measured from these casts. Histology was performed on structures defining the epiploic foramen in 2 horses. Laparoscopic images from 6 standing right flank procedures were reviewed. RESULTS The defining structures of the epiploic foramen and omental vestibule are the hepatoduodenal ligament, hepatogastric ligament and the gastropancreatic and hepatopancreatic folds. The hepatoduodenal ligament has a secondary fold which forms the ventral border of the epiploic foramen, consisting of a central connective tissue core of mainly elastin fibres. The hepatic artery for part of its course is incorporated in the hepatoduodenal ligament. All these structures are clearly visible laparoscopically. The mean circumference of the epiploic foramen is 11.6 ± 2.6 cm and its circumference is positively correlated with body weight but is unrelated to age or gender. CONCLUSIONS Several clinically relevant structures delineate the epiploic foramen. Its defining structure consists, in part, of elastin fibres. Anatomical and laparoscopic knowledge may assist surgeons in developing interventions to treat diseases involving the epiploic foramen.

The Microscopic Structure of the Omentum in Healthy Dogs: The Mystery Unravelled.

The canine omentum has many valuable properties but is still an underestimated organ. It contributes in many ways to the protection of the peritoneal cavity through its versatility on immunological level, but also through its role during angiogenesis, absorption, adhesion and fat storage. Despite a wide range of applications, the basic structure of the omentum is not well documented. This study provides an insight in the microscopic structure of the canine omentum through both light microscopic and electron microscopic investigations. Two regions could be distinguished in the canine omentum: translucent and adipose‐rich regions. The translucent regions were composed of two different layers: a continuous flattened mesothelium on top of a submesothelial connective tissue matrix. The adipose‐rich regions consisted of a substantial layer of adipocytes on which a flattened continuous mesothelium was present. Between those two layers, a few strands of collagen fibres could be detected. Large aggregates of immune cells, the so‐called milky spots, were not observed in the omentum of healthy dogs. Only a limited number of leucocytes, macrophages and neutrophils were found, scattered throughout the connective tissue in the translucent regions. At the level of the adipose‐rich regions, the immunological population was virtually non‐existent.

The Omental Pedicle Flap in Dogs Revised and Refined: A Cadaver Study.

OBJECTIVE To expand current knowledge on the canine omental vasculature and refine the existing lengthening technique of the canine omentum. STUDY DESIGN Ex vivo study. ANIMALS Canine cadavers (n=20). METHODS In 10 canine cadavers the omental arteries were mapped using intravascular latex injection and these results were used to create an omental pedicle flap based on the splenic artery in 10 additional cadavers. The operating range of the flap was recorded with particular attention to the main regions of interest for omental transposition in dogs (axillary and inguinal regions). RESULTS The superficial and deep omental leaves were each predominantly supplied by a left and a right marginal omental artery that anastomosed near the caudal omental border into a superficial and a deep omental arch, respectively. Anastomoses between arteries of the superficial and the deep omental leaves were weak and inconsistent, except for 1 anastomosis that was found in 8 of 10 dogs. By transposing the intact omentum, the right axilla could be reached in 3 dogs, both axillae in 1 dog, and both groins in all cadavers. In all cases, the omental pedicle reached to and beyond the axillary and inguinal regions. By unfolding the pedicle leaves, the width of the pedicle tip could be doubled. CONCLUSION When lengthening the omentum is necessary to reach extra-abdominal structures, the omental pedicle flap based on the splenic artery appears to preserve the omental vascular supply. These observations warrant further clinical trials to evaluate this new omtental flap technique in vivo.

Morphology of the Canine Omentum Part 1: Arterial Landmarks that Define the Omentum

Although the omentum remains an enigmatic organ, research during the last decades has revealed its fascinating functions including fat storage, fluid drainage, immune activity, angiogenesis and adhesion. While clinicians both in human and veterinary medicine are continuously exploring new potential omental applications, detailed anatomical data on the canine omentum are currently lacking, and information is often retrieved from human medicine. In this study, the topographic anatomy of the canine greater and lesser omentum is explored in depth. Current nomenclature is challenged, and a more detailed terminology is proposed. Consistent arteries that are contained within folds of the superficial omental wall are documented, described and named, as they can provide the anatomical landmarks that are necessary for unambiguous scientific communication on the canine omentum. In an included dissection video, the conclusions and in situ findings described in this study are demonstrated.

New extralimital record of a narwhal (**Monodon monoceros**) in Europe

On 27 April 2016, a dead narwhal (Monodon monoceros) was found on the bank of the River Scheldt, Belgium. It was the first record of this high Arctic cetacean in Belgium, and one of the most southerly records ever in Europe. Due to the decomposition of the carcass, the results of the autopsy remained inconclusive, but it is likely that the animal had died due to a long process of starvation. In the stomach, a large number of litter items were found which were probably ingested during the process of dying. We further provide information on the sighting of the live animal prior to the stranding and present an overview of the very few known records of narwhal in northwestern Europe.