2007 - Volume 34 - Issue 4

241-247
Case Report: Lymphosarcoma in Adult African Green Monkeys (Chlorocebus
Aethiops)
by JM Kagira, M Ngotho, JK Thuita, HE Jensen & J Hau

The clinical observations and pathological manifestations of lymphosarcoma in two African green monkeys are described. Monkeys had been caught from the wild. Prior to the development of neoplasms one monkey had been experimentally infected with Trypanosoma brucei rhodesiense as a model of human trypanosomiasis and subsequently treated with a proprietary trypanocidal drug and observed for any aftereffects. Th e other monkey was used to test for the safety of another trypanocidal drug. During the monitoring period, terminated by euthanasia, monkey became dull, unable to perch, and hunched. In the same animal the facial skin became hypersensitive and nodular skin lesions developed. In the other animal used in safety study, skin lesions, weight loss, and swollen eyelids were observed prior to euthanasia. During the terminal stages of the experimental protocol, the superficial lymph nodes of both animals became swollen, and the white blood cell count increased. Lesions disclosed during necropsy and subsequent histopathology revealed classical signs of nodular multicentric lymphosarcoma. In both animals the neoplastic infiltrates were dominated by large lymphocytes with anisokaryosis and megakaryosis. In several organs (lungs, liver and kidneys) of one of the animals, the neoplastic infiltrates were accompanied by compression and degeneration of bordering tissues. The cause of the neoplasms remains unknown, but stress-induced immunosuppression associated with captivity, to a lesser extent and, more importantly, the induction and treatment of experimental trypanosomiasis may, have triggered the onset of neoplastic proliferation, which is frequently associated with simian T-cell leukemia virus 1 (STLV-1).

255-263
Prolonged Exposure of Mice to a Nest Box Reduces Locomotor Activity in the Plus-Maze Test
by Kai Õkva, Aavo Lang, Timo Nevalainen, Marika Väli, Kari Mauranen & Paavo Pokk

Environmental enrichment (EE) has been associated with many effects on the behavior of laboratory animals. The term EE is rather vague, often referring to a variety of item combinations as if what is added to the cage has no significance. EE is indeed housing refinement, and therefore more exact terms should be used to clarify the situation. This study was designed to assess whether access to a nest box (NB) could modify behavior of BALB/c mice in the plus-maze test. Two series of experiments were done with an aspen NB (11 x 11 x 7 cm, wall thickness 1.5 cm, two round holes (d = 3 cm) at opposite sides. Control mice had no added item in the cage. The plus-maze consisted of two open (8 x 17 cm) and two closed arms (8 x 17 x 30 cm) connected by a central platform (8 x 8 cm). Mice were placed on the central platform facing an open arm. During five minutes, the numbers of entries made onto the open and into the closed arms were recorded. From this data, the percentages of entries made onto the open arms, and the percentage of time spent on the open arms, were calculated. Furthermore, the number of fecal boli left by the mice in the plusmaze, as a stress indicator, were counted. In the first series of experiments NB was present for one, two and three weeks but no drugs were administered. NB provided for one or two weeks had no effect on the behavior of mice. However, exposure to NB for three weeks did decrease the locomotor activity of mice in the plus-maze test, as reflected in the decline in the total number of entries made in the test. The presence of NB for one or two weeks resulted in more (p = 0.001) fecal boli voided when compared to the no NB or NB for three weeks groups. In the second series of experiments we used NB for 10 days and the selective neuronal nitric oxide synthase (nNOS) inhibitor 1-(2-trifluoromethylphenyl)-imidazole (TRIM) as a pharmacological tool (at doses of 25.0, 50.0 and 100.0 mg/kg, i.p.). Depending on the dose, the administration of TRIM induced an anxiolytic (50 mg/kg) or sedative effect (100 mg/kg) as seen in the increase in the percentage of entries made onto the open arms or a decrease in the total number of entries, respectively. NB for 10 days had no effect on the behavior of mice or on the effect of TRIM. In conclusion, NB does not appear to interfere with the anxiolytic effect of TRIM in the plus-maze test but prolonged exposure to NB does reduce the locomotor activity of mice.

269-278
Peripheral Progenitor Cell Graft in the Rat: A Technique of Graft Processing
by Rudolf Peceny, Jun Li, Heidong Chi, Olaf Dirsch, Ji Yuan, Dietrich W. Beelen & Uta Dahmen

The aim of this study was to establish a procedure for blood progenitor cell graft processing in rats. As a first step the mobilization protocol was optimized. The second step was dedicated to define the optimal source for subsequent graft manufacturing: either peripheral blood or spleen. The third step was designed to establish a protocol for purification of stem cells. The best mobilization results in terms of white blood cell count, granulocyte colony forming units (CFUG) and CD90 positive progenitor cells were obtained after pre-treatment of the donors for 5 days with recombinant human granulocyte colony stimulating factor (100 μg/kg) in combination with murine stem cell factor (33 μg/kg). Splenectomy prior to mobilization increased the yield of stem cells from peripheral blood. The numbers of CD90-positive progenitor cells recovered from the spleen of one rat after stem cell mobilization were sufficient to generate one stem cell graft. Grafts containing 1 x 106 progenitor cells – and thus sufficient for transplantation - were obtained after Tcell depletion and positive selection of CD90 positive cells. The grafts were characterized and showed a purity exceeding 70%, a T-cell depletion of 3.6 log10 and a 3-fold increase in CFU-G compared to the yield post mobilization.

283-289
Animal Models in Peritoneal Dialysis
by B Stojimirovic, J Trbojevic-Stankovic & D Nesic

Over the last decades peritoneal dialysis (PD) has become a successful and widely used treatment for endstage renal disease patients worldwide. Together with the increasing number of uremic patients successfully treated with PD has grown an interest in physiological, pathophysiological and clinical aspects of this therapeutic method. This article provides an overview of the current status on animal models used in studying the histology and physiology of the peritoneum, as well as the process of peritoneal dialysis itself. We discuss species of experimental animals, methods of peritoneal access, sampling for histology, different techniques and methodologies, and complications of experimental models of PD.

291-299
Suitability of Permanent Probe Implants For the Measurement of Intramedullary Perfusion and Temperature Near the Bone Cortex: A Pilot Study Using a Rabbit Model
by Mehrdad Bohloli, Hafize Uzun, Erman Aytac, Akin Savas Toklu, Melih Paksoy, Haydar Durak & Turgut Ipek

This study was conducted to test the suitability of permanent probe implants for the measurement of intramedullary perfusion by laser Doppler flowmetry and for the measurement of temperature near the bone cortex. Measurements were carried out on the conscious animal in order to rule out the influence of anaesthesia on intramedullary perfusion and temperature. During the first experimental animal trials, some of the probes made of polysulphon broke and/or gave false temperature measurements, so the original probe design was modified. The probes were reinforced with metal, and the temperature sensors were made less permeable to moisture. These modified probes were found to be suitable for permanent measurement of intramedullary perfusion and of temperature near the cortex in the conscious rabbit.