A catheter system for long-term intravenous infusion in unrestrained rats

An intravenous catheter system for long-term (at least 6-8 weeks) parenteral nutrition of unrestrained rats is described. The apparatus is inexpensive and can be constructed from commonly available materials.     

Technique for long-term infusion into the inferior mesenteric artery of unrestrained rats

A technique for long-term infusion into the inferior mesenteric artery was developed which allows simple and reliable regional infusion into the colorectal segment of unrestrained rats. The cannulation system consists of an injection port 'In Stoppers' as a flow swivel, connected to an injection needle, which is inserted into a polyethylene tube protected by a steel spiral. During infusion the animals are free to move in the cage with access to food and water ad libitum. The method is suitable for regional chemotherapy as well as for studies of colorectal tumours in rats. In this study 73% of the cannulae remained functional for continuous infusion over a 15 day period.     

Novel restraint system for neuroendocrine studies of socially living common marmoset monkeys

We describe a novel soft jacket and sling-harness restraint that permits species-typical postures for small-bodied primates, such as the common marmoset (Callithrix jacchus), during long-term (>6 h), continuous restraint. The restraint system is straightforward to use and manipulate, it is easily repaired, and the materials used are readily available. The soft jacket allows for increased versatility and longevity, and the sling-harness provides for greater movement and much longer duration of continuous restraint (up to 3 days) compared to a previously described, more conventional chair restraint for small-bodied primates. The new restraint system prevents the normal diurnal decrease in plasma cortisol levels across the daylight hours; however, it does not disrupt ovulatory cycles. Unlike the previously available techniques, therefore, this new restraint system is applicable to many neurobiological and neuroendocrine studies involving small-bodied, non-human primates and is especially suited to investigations requiring the maintenance of relationships within social groups.     

A simple and economic technique for long-term continuous intravenous infusion in the unrestrained rat

A reliable, inexpensive and ethically acceptable method for long-term intravenous infusion in unrestrained rats is described. This system absorbs rotational forces produced by the animal turning without kinking of the tube.     

Techniques for collecting saliva from awake, unrestrained, adult monkeys for cortisol assay

Cortisol levels serve as an index of pituitary-adrenal activity in nonhuman primates. In adult monkeys, cortisol is normally measured in blood (typically requiring restraint or sedation) or urine (reflecting a state rather than point estimate). In contrast, saliva collection is less invasive than drawing blood and allows for repeated sampling within a short period of time. Although protocols exist for collecting saliva from young monkeys, these procedures are inadequate for awake, unrestrained adult animals. Our laboratory has developed two methods for collecting saliva from adult rhesus monkeys: a "screen" method, which involves licking screen-covered gauze, and a "pole" method, which involves sucking and chewing on an attached rope. Twenty-three adult male rhesus monkeys were used to evaluate these two methods. After a period of adaptation, saliva samples were collected from 21 of 23 subjects. Saliva collection was faster with the pole than with the screen method (P < 0.01), but the pole method was not suitable for some animals because of their tendency to bite off the attached rope. An analysis of 19 saliva samples revealed a mean cortisol concentration of 0.84 microg/dl (range 0.27-1.77 microg/dl). There was no statistically significant difference in cortisol value between methods used (P > 0.22). The influence of the flavoring on the cortisol assay was tested, and was found to have no significant effect (P > 0.28). Our results indicate that either technique can be used to safely collect saliva from unrestrained adult monkeys. Choice of technique will depend on the proclivities of individual monkeys.     

A restraint system for the common marmoset (Callithrix jacchus)

A method for restraining the marmoset in a primate chair is described. The device is inexpensive to construct, is reliable, and the majority of animals can be habituated to its use. The chair has been used in neurobiological studies employing electrophysiological recordings, with or without concurrent collection of serial blood samples.     

LPS-induced lung inflammation in marmoset monkeys - an acute model for anti-inflammatory drug testing

Increasing incidence and substantial morbidity and mortality of respiratory diseases requires the development of new human-specific anti-inflammatory and disease-modifying therapeutics. Therefore, new predictive animal models that closely reflect human lung pathology are needed. In the current study, a tiered acute lipopolysaccharide (LPS)-induced inflammation model was established in marmoset monkeys (Callithrix jacchus) to reflect crucial features of inflammatory lung diseases. Firstly, in an ex vivo approach marmoset and, for the purposes of comparison, human precision-cut lung slices (PCLS) were stimulated with LPS in the presence or absence of the phosphodiesterase-4 (PDE4) inhibitor roflumilast. Pro-inflammatory cytokines including tumor necrosis factor-alpha (TNF-α) and macrophage inflammatory protein-1 beta (MIP-1β) were measured. The corticosteroid dexamethasone was used as treatment control. Secondly, in an in vivo approach marmosets were pre-treated with roflumilast or dexamethasone and unilaterally challenged with LPS. Ipsilateral bronchoalveolar lavage (BAL) was conducted 18 hours after LPS challenge. BAL fluid was processed and analyzed for neutrophils, TNF-α, and MIP-1β. TNF-α release in marmoset PCLS correlated significantly with human PCLS. Roflumilast treatment significantly reduced TNF-α secretion ex vivo in both species, with comparable half maximal inhibitory concentration (IC(50)). LPS instillation into marmoset lungs caused a profound inflammation as shown by neutrophilic influx and increased TNF-α and MIP-1β levels in BAL fluid. This inflammatory response was significantly suppressed by roflumilast and dexamethasone. The close similarity of marmoset and human lungs regarding LPS-induced inflammation and the significant anti-inflammatory effect of approved pharmaceuticals assess the suitability of marmoset monkeys to serve as a promising model for studying anti-inflammatory drugs.     

A three channel radio-controlled brain-stimulator for unrestrained animals

We have developed a project for biological radio-controlled electrostimulation, consisting in a three channel telestimulator, which has been used in our laboratories on animals unrestrained and complete freedom of movements. The system has been tested and used in many experiments which excellent results.     

A restraining system for rhesus monkeys used in space research

A new chronic restraining system has been designed specifically for male rhesus monkeys (8–13 kg) housed in weightlessness for scientific purposes. The restraining system consists of a coat (jacket and skirt) and a chair. The system separates the thorax from the lower part of the body, and allows large movements of the upper part of the body. The macaque can feed and groom itself, and can also sleep in close-to-normal position.     

A self-powered constant infusion device for use in unrestrained rats

We developed a device that delivers fluid through a catheter at a constant rate and can be used in conscious animals to solve a variety of problems. For example, this device can be used for delivering drugs and maintaining intravascular catheter patency. The device provides infusions at low flows (1.0-1.5 ml/day), so that experimental agents may be administered with minimal volume loading of the rat. Arterial and venous catheter patency is maintained by infusion of heparinized saline through indwelling catheters attached to the device. The catheters exit from the rat in the intrascapular area and are routed through a protective spring to the device, which is suspended above the cage. The catheters may be attached to pressure transducers, blood may be sampled, and injections or infusions may be made without disturbing the rat. Because the device is self-contained, it can be suspended by a fluid-free swivel that rotates through 360 degrees, providing minimal restraint. The device has been used successfully to measure arterial and central venous blood pressures in two studies using rats.     

A marmoset model for some New World dermatotropic leishmaniases

Callithrix penicillata is a good model for dermatotropic strains of some New World Leishmania species (L. mexicana mexicana, L. m. amazonensis, and L. braziliensis guyanensis). Both amastigotes and promastigotes readily infect these primates, with a relative short period of incubation. The developed lesions parallel those found in man, and despite the self healing presented by some marmosets, cell and serum immunological responses are presented. Skin alterations are confined to the site of inoculum, and visceralization is very rarely found. A good response to standard antimonial treatment makes the model useful for preclinical experiments with promising compounds.     

A three component water-biopolymer-ions system: a model for molecular mechanisms of osmotic homeostasis

It is shown that water-ion homeostasis in a water-biopolymer-salt system is realized when proportion of the concentrations of the components changes in the definite range. The mechanism of instantaneous osmotic regulating reaction is discussed, which is based on the ability of the system to physicochemical redistribution of the components of the solution and the formation of supramolecular structures in the form of dynamic biopolymer clusters. Quasiequilibrium biopolymer<-->cluster leads to changes in the properties of the hydration water phase that provide the stabilization of water activity and the ability of hydration water to dissolve electrolyte ions. It regulates osmotic pressure and surface tension in water-protein matrix. This process supports a balance of stabilizing and destabilizing forces that affect protein structure and determine its functional activity.