Long-term cannulation of the vena cava of rats for blood sampling: local and systemic effects observed by histopathology after six weeks of cannulation.

A cannulation system with fixation by a metal cuff around the tail was used for blood sampling. The cannula was guided subcutaneously and positioned in the vena cava after entering the body via the femoral vein. Histopathology was performed after long-term cannulation of up to 35 and 45 days. The presence of the cannula in the vena cava induced endothelial hypertrophy and hyperplasia accompanied by stromal hypertrophy. The endothelial activation was not limited to the vena cava but was also observed in both the cannulated vena iliaca and the contralateral control vena iliaca, the latter showing only minor alterations. In the lung, thrombi were noted in the larger lung arteries; and foreign body emboli, probably situated in the alveolar septi, could be detected occasionally. Inflammatory reactions in the tail at the site of cuff fixation consisted of a mixture of acute and chronic inflammatory responses. The chronic inflammation extended into the tail muscles, as shown by the presence of fibrous tissue associated with muscle degeneration. In conclusion, prolonged venous cannulation in rats resulted in local alterations in the veins, small emboli in the lungs and a moderate to marked inflammation in the tail. However, the procedure itself was well tolerated by the animals.     

Non-surgical cannulation of the vena cava for chronic blood collection in mature swine.

A nonsurgical cannulation technique for blood collections from mature swine was evaluated. Primiparous Yorkshire-Landrace sows (n = 6) received an indwelling jugular vein cannulae for 7 days duration. Recannulation was performed at monthly intervals for a total of 14 months. During cannulation, sows were restrained in a standing position using a rope snout snare. A 12-gauge by 10 cm needle was inserted into the jugular vein. Sterilized polyvinyl chloride tubing was advanced through the needle into the vein and a blunted 18-gauge needle and attached intermittent injection hub was inserted into the free end of the tubing. Surgical tape was used to form a butterfly on the tubing by suturing the tape to the animals' skin. Foam padding, livestock cement, and elastic tape helped to keep the tubing in position. Problems with cannulae patency and maintenance were few. No behavioral problems or systemic signs of illness were noted and necropsy examinations performed after the final cannulation revealed few abnormalities associated with chronic intermittent cannulation. This technique provides a safe, quick, effective means for multiple and repeated cannulae placement for blood collection from mature swine with minimal effects on the animal and without the risks associated with surgical techniques.     

Anomalous caudal vena cava passing through the vertebral canal in a calf

A 15-day-old female Holstein-Friesian calf with an anomalous caudal vena cava was examined macroscopically, roentgenologically, and histologically. The calf, weighing 43 kg, had severe scoliosis. A common renal vein merged into a single venous trunk formed by the union of the left and right common iliac veins. The trunk entered the vertebral canal through the left intervertebral foramen formed by the last (13th) thoracic and the first lumbar vertebrae. The trunk continued along the ventral side of the narrowing spinal cord inside the canal, and then ran out the left intervertebral foramen formed by the 8th and 9th thoracic vertebrae and emptied via the right azygos vein into the cranial vena cava. In contrast, the hepatic vein passed through the foramen vena cava independently of the trunk and entered the right atrium directly. The pathogenesis of the present anomaly may be explained as follows: The right subcardinal vein, failing to make connection with the liver, shunted directly into the right azygos vein derived from the right supracardinal vein. The body axis began to curve before ossification of the vertebrae occurred. Consequently, the developing right supracardinal vein, located close to the spinal cord, is thought to have become enclosed in the vertebrae with the spinal cord during the early fetal stages.     

Blood sampling from the cranial vena cava in the Norway rat (Rattus norvegicus)

This paper describes blood sampling from the cranial vena cava (CVC) in the Norway rat. In order to limit stress, the blood sampling should be done under short-term inhalation anaesthesia, for example, an oxygen/isoflurane mixture. The injection site is just cranial to the first rib, 0.3-0.8 cm lateral to the manubrium when the animal is in dorsal recumbency. The needle, attached to a syringe, is inserted at 30 degrees in the direction of the opposite femoral head. After penetration of the skin, negative pressure is developed in the syringe and the insertion of the needle is continued for another 0.2-1 cm in the given direction until blood begins to flow. The amount of blood sampled ranges from 0.8 to 2.5 mL depending on the body weight of the patient. A trial on 50 rats aged 5-24 months included 25 rats sampled once, eight rats sampled twice with an interval of seven days, 11 rats sampled twice with an interval of three weeks and four rats sampled four times with intervals of four weeks--a total of 87 blood samplings. The serious complications quoted in association with blood sampling from the CVC in other experimental animals (vascular lacerations, heart puncture, serious haemorrhage, tracheal and throat trauma) were not observed in our study. There were only four blood samplings (4.5%) with mild haemorrhage from the injection site, due to erroneous sampling from the jugular vein.     

Venous valves in the large branches of superior vena cava

In 97 human cadavers the valves of the following blood vessels were investigated with regard to their cusps and their sizes and positions: the internal jugular veins, the subclavian veins, the brachiocephalic veins, and the superior vena cava. The cusps of each of the valves, which consist of two or three parts, are neither always of equal size nor obligatorily sufficient. Unipartite valves may be sufficient as well as insufficient. Internal jugular veins: The inferior bulb of the internal jugular vein is provided with valves which in 6% of the cases consist of three parts, in 66% of two parts, and in 15% of only one cusp. The concave margins of most of them go down as far as the venous angle. The convex edges attached to the wall of the vein extend to a higher level on the right side than on the left. In 13% there do not exist any valves. Varieties are described separately in this paper. Subclavian veins: Valves are found along the length of the vessel. Only few of them reach the venous angle. In rare cases there exist two valves: one at the beginning, the other at the end of the subclavian vein. In 4% of the cases the valves consist of three, in 75% of two cusps. In 12% they are unipartite. In 9% there are no valves to be found. The right side is more often without valves than the left. Brachiocephalic veins: Only a minority of these vessels is provided with valves. Most of these consist of one cusp, are insufficient, and are situated in the left innominate vein.(ABSTRACT TRUNCATED AT 250 WORDS)     

Best practices for non-lethal blood sampling of fish via the caudal vasculature

Mature male and female little skates Leucoraja erinacea were injected with oxytetracycline and maintained in captivity for 13 months to assess centrum growth and the frequency of band-pair deposition. Sixty per cent of the individuals analysed did not deposit a full band pair over the 13 month period. Thus, a majority of captive skates did not exhibit annual band-pair deposition. Previous research confirms annual band-pair deposition in all juvenile and most adult L. erinacea, therefore sexual maturation may lead to decreased frequency of band-pair formation. Age underestimation of larger, older elasmobranchs is being identified in an increasing number of elasmobranch species including L. erinacea as demonstrated in this study. The effect of age underestimation from band-pair counts on studies that use age-based characteristics needs to be addressed.     

A model for passive elastic properties of rat vena cava

A two-dimensional model for the elastic properties of vena cava abdominalis under orthotropic deformation is introduced and tested against the experimental data obtained from six specimen of rat venae cavae by pressurization experiments. The model is based on membrane approximation and suited for vessels where most of the elastic elements are oriented axially, while circumferential contraction is exerted by redirecting axial stress by some network of oblique fibers. For the experimental data considered in this paper, the ratio between axial and circumferential stress depends almost exclusively on the circumferential extension ratio. As a consequence, the mechanical system can be formally decomposed in a kinematic system reacting by axial contraction on circumferential extension without any loss or storage of energy, serially connected to a hyperelastic system acting only in axial direction. Both systems are modeled separately by equations obtained by a purely phenomenological approach with two parameters for each system. This leads to reasonable reproduction of the experimental data. Introducing a correction parameter, which takes into account that the model assumption on the decomposition does not hold exactly, we get better reproduction of data. However, this is paid for by loss of physical rigor and in particular by departing from the assumption of hyperelasticity.