bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of male reproductive parameters in three rat strains: Dark Agouti, Sprague-Dawley and Wistar
Authors: Wilkinson J. M. , Halley S. , Towers P. A.
Published: April 2007

The choice of experimental animal can have a large impact on experimental results, an example is the anecdotal evidence suggesting that Dark Agouti (DA) rats have a lower reproductive capacity than other rat strains. In this paper we report on an investigation into male reproductive characteristics in three rat strains-Wistar, Sprague-Dawley (outbred strains) and DA (an inbred strain). Reproductive organ weights, blood testosterone levels and sperm counts were measured in mature age-matched male rats. DA animals had significantly smaller testis weights than the Sprague-Dawley and Wistar animals, and this did not appear to be related to the overall smaller body mass of the DAs. There were no differences between the three strains in testicular histology or sperm counts (per gram testis). Although there was also no significant difference in epididymal sperm count, the DA animals had a much greater variability in sperm count than the other strains. There were no differences in relative (to body weight) epididymal, seminal vesicle or ventral prostate weights or in the blood testosterone levels. These results suggest that differences in reproductive capacity in DAs are neither the result of morphological differences in the reproductive organs nor in circulating testosterone levels. Sperm production appears to be normal but the lowered testicular weight and variability in epididymal sperm counts suggests that there are other factors in the testicular or epididymal environment which alter male reproductive function.
Immunological characterization of C3H mice congenic for Faslprcg, C3H/HeJ-Faslprcg/Faslprcg
Authors: Yasuda Takuwa , Zhang Yan , Nagase Hisashi , Kaneko Tetsuya , Sayama Kazutoshi , Hashimoto Hajime , Matsuzawa Akio
Published: April 2007

Faslpr( lpr) and Faslprcg ( lprcg) are allelic mutations of the Fas gene that is involved in apoptosis or programmed cell death. Lpr greatly reduces the expression of functional Fas and lprcg expresses the death domain-disabled, non-functional Fas on the cell surface. C3H/HeJ mice congenic for lprcg (C3H- lprcg) were established and compared with C3H/HeJ- lpr/lpr (C3H- lpr) mice for their immunological and pathological features. Lymphadenopathy, splenomegaly, development of CD4-CD8-B220+ or double-negative (DN) T cells, renal pathology, and lymphoid cell infiltration in the lung and liver were not significantly different between C3H- lprcg and C3H- lpr mice. Noticeably, however, the production of serum immunoglobulin, autoantibodies against double-strand DNA and serum immune complexes were significantly lower in C3H- lprcg than in C3H- lpr mice. The results indicate that the death signal through the death domain of Fas is responsible for lymphoproliferation due to the accumulation of DN T cells and suggest that the region of Fas outside the death domain may be involved in autoantibody production. The newly-developed congenic C3H- lprcg mice will provide a powerful tool for research into the function of Fas apart from apoptosis.
The effect of chronic food and water restriction on open-field behaviour and serum corticosterone levels in rats
Authors: Heiderstadt K. M. , McLaughlin R. M. , Wrighe D. C. , Walker S. E. , Gomez-Sanchez C. E.
Published: April 2007

In operant conditioning experiments, two methods are commonly used to motivate laboratory rats to perform designated tasks. The first is restricting food so that rats are forced to lose 20% of body weight within one week, followed by maintenance at 80% of the baseline weight for the remainder of the experiment. The second is restricting access to water to 15 min in each 24 h period. These methods are effective in motivating the animals. There is, however, little information available on the effects on performance in tests of behaviour that are not related to operant conditioning. In addition, it is not clear if these commonly used methods of food and water restriction will lead to physiological stress as indicated by an elevation of serum corticosterone. Male rats were either food-restricted to reduce and maintain their weight at 80% of baseline weight, or were restricted to 15 min access to water every 24 h. Activity in the open field was significantly greater in food-restricted rats than in water-restricted or control rats, but freezing behaviour was similar in all experimental groups. Food-restricted rats had a higher mean serum corticosterone level than water-restricted and control rats 37 days after the start of the experimental period. These data suggested that chronically restricting food and maintenance of body weight at 80% of baseline body weight led to significant behavioural changes and physiological stress. In contrast, water restriction did not lead to changes in behaviour or corticosterone levels. A second experiment was conducted to compare the effects of food restriction to 80% of baseline body weight, as described above, with a less stringent protocol in which test rats were initially reduced to 80% of baseline weight, but were then maintained at 80% of an ad libitum fed control rat's weight. Serum corticosterone levels and adrenal gland weights were measured after the initial week of forced weight loss and after maintenance for 21 days. Forced loss of 20% of body weight in the first week led to significantly increased serum corticosterone levels and adrenal gland weights compared to ad libitum fed controls. Serum corticosterone levels and adrenal gland weights in rats maintained at 80% of their initial body weight for 21 days remained higher than ad libitum fed control rats. However, rats maintained at 80% of an ad libitum fed control rat's weight did not differ from control rats in serum corticosterone levels or adrenal gland weights at the end of the 21-day study period. Adjustment of the feeding regimen in this manner eliminated physiological evidence of chronic stress.
Potency of propofol, thiopentone and ketamine at various endpoints in New Zealand White rabbits
Authors: Mustola S. T. , Rorarius M. G. F. , Baer G. A. , Rosenberg P. , Seppälä T. , Harmoinen A.
Published: April 2007

Effective plasma concentrations of propofol, thiopentone and ketamine were determined at different endpoints in a study with randomized, crossover design in nine New Zealand White rabbits. A continuous infusion was used (30 ml/h) with concentrations of 10 mg/ml for propofol, 25 mg/ml for thiopentone and 20 mg/ml for ketamine. The endpoints were loss of the righting reflex, loss of purposeful reactions to tail clamping (as an example of a peripheral pain stimulus) or to intranostril insufflation of ammonia vapour (as an example of a central reflex stimulus), and the recovery of these reflexes and reactions. According to the ED50 values the potency ratios of propofol, thiopentone and ketamine were at the loss of righting reflex 1:1.8:1.2, at the loss of reaction to ammonia vapour 1:1.5:1.6, and at the loss of reaction to tail clamping 1:1.5:3.9, respectively. Recovery was significantly faster after propofol than after thiopentone and ketamine. Measuring the effective plasma concentrations of intravenous anaesthetics provides a method of relating dose to effect, but there still remains a variable gap between plasma concentration and effect.
Euthanasia of rats with carbon dioxide-animal welfare aspects
Authors: Hackbarth H. , Küppers N. , Bohnet W.
Published: April 2007

A method of inducing euthanasia by carbon dioxide (CO2) inhalation in the home cage of an animal is described and tested for distress by behavioural as well as by hormonal measures. The animals were maintained in their home cage while CO2 was induced at a flow of 6 l/min. The behaviour of the animals was measured continuously as were the serum concentrations of glucose, ACTH and corticosterone 30, 75 and 120 s after the CO2 was introduced into the cage. In order to test for distress, two groups of rats were pre-treated with acepromazine (orally) and pentobarbiturate (i.p. injection) respectively, in order to reduce possible distress caused by CO2 euthanasia, and were compared with control groups. There were no signs of distress by behavioural or by hormonal changes. All changes seen could be attributed to experimental effects and, especially as there was no difference between the pre-treated and the control groups of rats, it must be assumed that the described method of euthanasia is in concordance with animal welfare, it leads to rapid death without severe distress or pain, and it seems therefore to be 'humane'.
Identification of select lymphocyte homing molecules and vascular addressins in lymphotoxin-alpha deficient mice
Authors: Davis I. A. , Rouse B. T.
Published: April 2007

The transmigration of lymphocytes across vascular endothelium is a critical step for the localization of lymphocytes to lymph nodes in both naïve and immune reactive states. Mice deficient in lymphotoxin-alpha (LT- α)lack peripheral and gut associated lymph nodes. Lymphocyte function and homing ability are reported to be normal in these mice yet information regarding cell adhesion molecules and counterpart vascular addressins is lacking. The phenotype of peripheral lymphocytes from LT- α deficient mice was investigated by the use of fluorescent activated cell sorting and immunohistochemistry. No difference was detected in the splenocyte and tissue expression of L-selectin, α4 β7 or its individual integrin components, mucosal addressin cell adhesion molecule (MAdCAM-1), intracellular adhesion molecule (ICAM-1), peripheral node addressin (PNAd), or platelet/endothelial cell adhesion molecule (PECAM-1) between wild-type and LT- α deficient mice. Therefore, impaired expression of these lymphocyte homing and vascular addressin molecules is apparently not included in the phenotype of the LT- α deficient mouse.
A pathophysiological study of abdominal organs following intraperitoneal injections of chloral hydrate in rats: comparison between two anaesthesia protocols
Authors: Vachon Pascal , Faubert Stéphane , Blais Diane , Comtois Alain , Bienvenu Jean Guy
Published: April 2007

Chloral hydrate (CH) is used as an anaesthetic agent in laboratory rats. Side effects occurring with high concentrations have mainly occurred in abdominal organs. The objective of the present study was to minimize these side effects following intraperitoneal administration of CH using lower concentrations. Animals were evaluated using different procedures including a general necropsy, intraperitoneal white cell counts, histology and duodenal peristalsis and acetylcholine-induced contractions. Results clearly show that lower concentrations of CH while keeping the same anaesthetic dose (400 mg/kg) will minimize the irritancy of CH on abdonimal organs while providing the same level of anaesthesia.
Development of an injectable sustained-release formulation of morphine: antinociceptive properties in rats
Authors: Tasker R. A. R. , Connell B. J. , Ross S. J. , Elson C. M.
Published: April 2007

The antinociceptive actions of morphine incorporated into an injectable chitosan-based gel were investigated in rats. Subcutaneous administration of 4.8 mg/kg morphine sulphate in a gel composed of N,O-carboxymethylchitosan (NOCC) and chitosan resulted in significant antinociception within 10 min that was maximal at 60 min and persisted for 6 h. In contrast, the same dose of morphine sulphate injected in sterile saline produced maximal responses at 30 min but only persisted for 2 h. NOCC/chitosan gel was easily injectable using a 22 guage needle and appears stable in long-term storage. No local or systemic adverse effects other than morphine-induced sedation were observed either at the time of injection or during the subsequent 48 h. We conclude that gels composed of chitosan and chitosan derivatives are effective matrices for sustained-release formulations of opioid analgesics capable of providing long-lasting antinociception.
Hyperkeratosis-associated coryneform infection in severe combined immunodeficient mice
Authors: Scanziani E. , Gobbi A , Crippa L. , Giusti A. M. , Pesenti E. , Cavalletti E. , Luini M.
Published: April 2007

Hyperkeratosis-associated coryneform (HAC) is a coryneform bacterium, with a biochemical profile similar to Corynebacterium bovis, that causes hyperkeratotic dermatitis in athymic nude mice. In the present study 28 severe combined immunodeficient (SCID) mice coming from six different animal facilities were submitted for bacteriological and pathological examination. HAC was isolated from 10 SCID mice belonging to two of these facilities. Two of the HAC-infected mice showed macroscopical lesions consisting in large alopecic areas, with small white flakes, involving the dorsum, flanks, neck and cheeks. Histologically, the skin of these animals was characterized by diffuse acanthosis and hyperkeratosis. In the other eight HAC-infected SCID mice no macroscopical lesions were observed but focal areas of minimal to mild acanthosis were histologically detected in five cases. These results suggest that HAC can infect SCID mice inducing skin lesions similar, although generally less severe, to those observed in nude mice with hyperkeratotic dermatitis. Our results pointed out that SCID mice may play an important role in the epidemiology of hyperkeratotic dermatitis of athymic nude mice.
Influence of nutritional iron deficiency development on some aspects of iron, copper and zinc metabolism
Authors: Rodriguez-Matas M. C. , Lisbona F. , Gómez-Ayala A. E. , López-Aliaga I. , Campos M. S.
Published: April 2007

This paper examines the development of iron (Fe) deficiency and its possible interactions with trace elements such as zinc (Zn) and copper (Cu) by investigating iron-deficient and control rats. The effects of iron deficiency were studied at day 0, 10, 20, 30 and 40 in rats fed on an iron-free diet (diet ID). It was found that the critical period in the development of nutritional iron deficiency occurs after 30 to 40 days without iron supplementation. At this time the organism is unable to maintain haemoglobin levels without endangering the iron-dependent enzymatic groups which are essential for life. It was also demonstrated that in a situation of iron deficiency, there occurs a greater absorption of copper, while that of zinc remains unchanged. As iron deficiency progresses, the levels of copper in the spleen and the sternum increase. It is apparent that iron deficiency provokes more marked alterations in the metabolism of copper than of zinc.
Hormone dependency of splenic iron stores in the rat: effect of oestrogens on the recuperation of reserves in ferrodeficient subjects
Authors: Borràs Miquel
Published: April 2007

Splenic iron stores are negligible in prepuberal rats, increasing quickly from the age of 2 months (at which moment sexual differences become apparent) and stabilizing around 3 months, when females show values approximately two-fold greater than males.

Castration, adrenalectomy and hormone replacement studies show that the amount of iron stored depends directly on circulating oestrogens and is slightly but not significantly decreased, in our experimental conditions, by testosterone.

The role of oestrogens is emphasized by the high correlation obtained, according to a hyperbolic regression model, between splenic iron values and doses of hormone administered to ovariectomized females.

In ferrodeficient females (chronic phlebotomy), oestradiol had a positive effect on the replenishment of the stores, superior to that of iron dextran, and improved by combined treatment. However, iron levels found after a single dose were less than those found in non-phlebotomized animals.
Bioelectrical impedance analysis for the estimation of body composition in rats
Authors: Rutter K. , Hennoste L. , Ward L. C. , Cornish B. H. , Thomas B. J.
Published: April 2007

Bioelectrical impedance analysis (BIA) was used to assess body composition in rats fed on either standard laboratory diet or on a high-fat diet designed to induce obesity. Bioelectrical impedance analysis predictions of total body water and thus fat-free mass (FFM) for the group mean values were generally within 5% of the measured values by tritiated water (3H2O) dilution. The limits of agreement for the procedure were, however, large, approximately ±25%, limiting the applicability of the technique for measurement of body composition in individual animals.
The absorption of iron, calcium, phosphorus, magnesium, copper and zinc in the jejunum–ileum of control and iron-deficient rats
Authors: Gómez-Ayala A. E. , Lisbona F. , López-Aliaga I. , Pallarés I. , Barrionuevo M. , Hartiti S. , Rodríguez-Matas M. C. , Campos M. S.
Published: April 2007

The effects of iron deficiency on the absorption of different dietary sources of iron were studied, together with the interactions' between iron, calcium, phosphorus, magnesium, copper and zinc in the jejenum–ileum of control and iron-deficient rats. In this study, three perfusion solutions containing different iron sources: ferric citrate, haemoglobin, and equal parts of ferric citrate and haemoglobin were used. In addition, the same perfusion solutions were used with and without 2,4-dinitrophenol, an inhibitor of oxidative phosphorylation. Iron absorption in anaemic rats was greater than in the controls, except after perfusion with solutions containing haemoglobin. The absorption of calcium, copper and zinc in iron-deficient animals was not significantly affected, while the absorption of phosphorus and magnesium increased, with respect to animals in the control group. After perfusion with solutions containing haemoglobin, the absorption values of calcium, copper and zinc were lower than after ferric citrate in both groups (control and iron-deficient rats).
Evidence of genetic heterogeneity in a BALB/c mouse colony as determined by DNA fingerprinting
Authors: Benavides F. , Cazalla D. , Pereira C. , Fontanals A. , Salaverri M. , Goldman A. , Buggiano V. , Dran G. , Corley E.
Published: April 2007

A genetic monitoring of the BALB/c mouse foundation colony in our animal facility was carried out. The techniques of choice were skin grafting, coat colour test, flow cytometric analysis for H2 antigens (loci H2-D and H2-A), electrophoretic analysis of isoenzymes (loci Idh1, Pep3, Es3 and Mod1), PCR-amplified microsatellites (loci Igh-V, Ngfg, Plau, Crp, Igh, D16Mit5, D3Mit49 and D17Mit16) and DNA fingerprinting (multilocus probes 33.6, 33.15 and (CAC)5). No evidence of genetic contamination was found, ruling out the possibility of an outcross with AKR, the other albino strain maintained at the facility. Nevertheless, DNA fingerprint patterns revealed evidence of genetic heterogeneity in four out of nine lines of the nucleus colony, interpreted as minisatellite mutations favoured for a single line system with more than 40 generations of separation from the ancestral pair. These mice are mainly used in cancer and immunological research within the institute.
Operant studies to determine the strength of preference in laboratory rats for nest-boxes and nesting materials
Authors: Manser C. E. , Broom D. M. , Overend P. , Morris T. H.
Published: April 2007

Previous work has shown that laboratory rats preferred to use nest-boxes and nesting materials rather than empty parts of the cage. In preference tests, they chose opaque or semi-opaque nest-boxes and long strips of soft paper nesting material. Choice tests to demonstrate a preference between nest-boxes and nesting material were not possible because nesting materials were carried into the nest-boxes. Furthermore, preference tests did not show how important these items were to the animals. Accordingly, operant tests were conducted, in which the rats had to lift a weighted door in order to gain access to an empty cage, or one containing a nest-box, nesting material or both items. By progressively increasing the weight of the door in subsequent trials, it was shown that the rats would carry out more work to reach a nest-box, with or without nesting material, than to reach an empty cage.
Effect of transatlantic transport on reproduction of agouti and nonagouti deer mice, Peromyscus maniculatus
Authors: Hayssen V.
Published: April 2007

In conjunction with establishing colonies of deer mice in the UK, effects of transportation on reproduction in agouti (A) and nonagouti (a) deer mice were assessed. Adults were shipped via ground courier and air freight from Northampton, Massachusetts, USA to Sutton Bonington, Leicestershire, England in February and June. Deer mice were paired upon arrival in Sutton Bonington, whereas matched controls were paired in the original colonies at shipping. To assess reproduction, the following variables were monitored for 110 days for all 96 pairs: number of pairs producing litters, time from pairing to birth, interlitter interval, litter size at birth, and litter size at weaning.

Generally, shipping suppressed litter production and delayed its timing, but had less effect on litter size. Overall, 32 of 48 control pairs (67%) produced 69 litters compared with 37 litters from 21 of 48 pairs (44%) after shipping. Pairing-to-first-litter intervals were approximately two oestrous cycles shorter in control animals (39 vs 53 days). Averaged over all litters, litter size was higher in control pairs (4.4 vs 4.0).

With respect to genotype, control agouti deer mice were less productive than nonagouti animals, but they reproduced better than nonagoutis after shipping. In control animals, colourmorphs did not differ with respect to litter production or timing, but agouti pairs had smaller litters (first litter: A: 3.1, a: 4.2) and this difference increased at successive litters (third litter A: 3.9, a: 6.0). After shipping, agouti animals produced more litters (A: 22, a: 15), and did so earlier (pairing to birth: A: 47 days, a: 60 days), as well as more frequently (interlitter interval: A: 32 days, a: 51 days). Litter size was also more similar between genotypes after shipping (A: 4.0, a: 4.1). Overall, control agouti animals produced 37% fewer offspring than nonagouti pairs (A: 116 neonates, a: 185 neonates), but after shipping agouti deer mice produced 43% more offspring than nonagouti animals (A: 87 neonates, a: 61 neonates). In sum, transport stress suppressed reproduction for several weeks after shipping and this suppression was exacerbated in nonagouti deer mice.
The effect of buprenorphine on the course of disease in laboratory rabbits infected with myxoma virus
Authors: Robinson A. J. , Müller W. J. , Braid A. L. , Kerr P. J.
Published: April 2007

The only method of assessing the virulence of myxoma virus is to record survival times of rabbits inoculated with the virus. This raises ethical concerns about using animals in experiments where death is the end point. We investigated whether or not the opioid analgesic buprenorphine could be used in rabbits without compromising the myxoma virus virulence assay and on the presumption that animals may suffer pain during the course of the disease. Thirty, 5-month-old New Zealand White rabbits were divided into two groups stratified for weight and gender, and inoculated intradermally with 100 pfu of the Standard Laboratory Strain (SLS) of myxoma virus. At day 6 post infection (p.i.), when eyelid swelling was first seen, each animal in one group was treated with 0.03 mg/kg buprenorphine, subcutaneously, morning and evening until death. Animals in the other group were untreated. Animals were weighed daily and rectal temperatures taken morning and evening. Intake of food and water was assessed as was general demeanour including respiratory effort. There was no significant difference in mean survival time, weight change, or demeanor between the two groups. Increased respiratory effort was seen from day 10 p.i. in animals surviving up to and beyond that time but again there was no difference between groups. Animals treated with buprenorphine refused food and water a day earlier than untreated animals, and had lower temperatures immediately prior to death. It was concluded that the opiate analgesic buprenorphine can be used without compromising the current virulence assay for the SLS of myxoma virus in New Zealand White rabbits but that the clinical signs of myxomatosis that could be attributed to pain were not abrogated.
Immunohistological characterization of leukocytes in the lungs of healthy mice and after bacterial intratracheal infection
Authors: Heitmann S. , Tschernig T. , Larbig M. , Steinmetz I. , Hedrich H.-J. , Pabst R.
Published: April 2007

Leukocytes in the peripheral lung parenchyma of mice have not been characterized histologically during bacterial infection. The aim of this study was to investigate (a) the immunohistological characteristics of healthy murine lungs and (b) the cell kinetics during acute inflammation. BALB/c and MF1 mice were examined; as well as transgenic mice with the gene defect of cystic fibrosis (CF) in the airways as an animal model for this disease. MF1 mice served as controls for the transgenic animals. Lavaged and perfused lungs were snap frozen. B and T lymphocytes, CD4+ and CD8+ cells, dendritic cells, neutrophils and a subset of macrophages were enumerated on cryostat lung sections. The lung tissue and bronchoalveolar lavage (BAL) of BALB/c mice, infected intratracheally with Haemophilus influenzae type b (Hib), were studied at different time points after infection. In the lungs of healthy mice, including CF mice, the largest population was that of T cells, CD4+ cells being always more frequent than CD8+ cells. During acute inflammation the number of neutrophils in the lung parenchyma and BAL increased strongly within the first hours after bacterial instillation and reached baseline levels within one week. This study provides a semi-quantitative analysis of immunocompetent cells in normal and infected murine lung tissue. Differences in cell numbers are found between different strains. Moreover, the cellular reaction during Hib infection in mouse lungs is dominated by neutrophils, as expected in a primary immune response. In uninfected CF mice the numbers and distribution of immune cells in the lung tissue are normal, indicating that the cellular defense is adequate.
Techniques of embryo transfer and facility decontamination used to improve the health and welfare of transgenic mice
Authors: Morrell J. M.
Published: April 2007

'Reduction' and 'Refinement' can be achieved in transgenic mouse studies by re-deriving transgenic mouse lines and subsequently maintaining them under high standards of husbandry in a unit with restricted access. This report describes the initial steps of a project to improve the health and welfare of transgenic mice at the European Molecular Biology Laboratory (EMBL), by re-deriving transgenic lines as microbiologically defined animals to be maintained in a barrier unit in a newly constructed animal facility.

A pilot study showed that it was possible to transfer embryos obtained from contaminated donor mice in the old facility to specific pathogen free recipients housed in a ventilated cabinet in the new unit, without concomitant carry over of disease. The offspring born following embryo transfer were of high health status and did not show any evidence of contamination with any of the pathogens present in the mice in the old animal unit. Antibodies to various murine viruses (mouse hepatitis virus (MHV), rota virus, reo-3 virus, Theilers encephalomyelitis virus, adenovirus) and parasites were present in sentinel animals from the old animal house whereas the re-derived animals were found to be free of virus antibodies and parasites. Therefore the methods used were considered to be successful in terms of disease prevention and enhancement of welfare.

The barrier unit was sterilized without the use of formaldehyde or related substances, to minimize the risks to personnel and to the environment from using potentially dangerous substances. From the results of in vitro and in vivo screening, the protocol for sterilization described here was found to be effective in achieving microbiological sterility of the barrier unit and was cost effective.
The effect of cage size and enrichment on core temperature and febrile response of the golden hamster
Authors: Kuhnen Gernot
Published: April 2007

The aim of this study is to determine the effect of cage size and cage enrichment. Golden hamsters were individually housed in standard cages of four different sizes and in enriched cages of three different sizes since 3 weeks of age. Each of the seven housing groups consisted of 12 hamsters. After 14 weeks of housing in their respective environments the measurements started. The mean baseline rectal temperature was significantly higher in hamsters housed in small cages than in hamsters housed in large cages. After the injection of fever-inducing lipopolysaccharide rectal temperature increased by 1 to 2°C. The increase of rectal temperature and the fever index were the highest in animals housed in large cages and the smallest in animals housed in small cages. Through cage enrichment and increasing cage size the mean febrile response increased while the mean baseline rectal temperature decreased. Cage size and cage enrichment had no effect on the dispersion of the measured values. The differences in microclimate between large and small cages were too small to have an effect on thermoregulation. The results indicate that housing in small cages induce chronic stress which obviously affects thermoregulation. The findings demonstrate that the results of some physiological experiments are significantly influenced by the pre-experimental housing conditions.
Aspen wood-wool is preferred as a resting place, but does not affect intracage fighting of male BALB/c and C57BL/6J mice
Authors: Eskola Satu , Kaliste-Korhonen Eila
Published: April 2007

Aspen wood-wool, provided as nesting material, was evaluated as a possible improvement of cage environment for 10-14-week-old inbred male mice maintained in groups of six (BALB/c n = 72 and C57BL/6J n = 36). The daily behaviour of mice was video recorded and their body weight, food consumption, weights of some organs and serum corticosterone concentrations were measured. Aggressive interactions between cage mates and against a strange intruder as well as the number of wounds on the back of the animals was monitored in order to evaluate the effect of nesting material on intermale aggression.

Nesting material did not affect the daily active/passive behaviour patterns of mice, although animals clearly preferred it as a resting place. BALB/c mice given nesting material showed less weight gain and smaller brown adipose tissue weights than animals without nesting material. The other characteristics measured were not affected by the presence of nesting material in either strain. The presence of nesting material had no effect on fighting in cages. C57BL/6J mice were more aggressive than BALB/c mice according to the number of wounded animals in a cage. Wounded BALB/c mice had enlarged spleens and decreased epididymal adipose tissue weights.

In conclusion, the nesting material used in this study did not adversely affect the animals. On the other hand, the material was clearly preferred to conventional bedding as a resting place. These findings suggest that nesting material may improve the cage environment of laboratory mice. Furthermore, there was an indication of strain differences in aggressive behaviour. It could be suggested that C57BL/6J mice are less tolerant towards intruders and housing six mice per cage is not suitable for this strain.
Adaptation of corticosterone-but not β-endorphin-secretion to repeated blood sampling in rats
Authors: Haemisch A. , Guerra G. , Furkert J.
Published: April 2007

Effects of short-term repeated blood sampling on the secretion of corticosterone (CORT) and β-endorphin ( β-END) were evaluated in male Wistar rats. Blood was drawn from the tail vein of conscious rats four times within 2 h both at the peak and trough period of the diurnal corticosterone secretion cycle. All rats were well accustomed to the procedure. The main findings were: (1) At both sampling intervals, CORT increased significantly in response to the first sampling and declined to baseline values in successive samples. (2) β-END also increased significantly in response to the first sampling but remained elevated in successive samples. (3) Intensities of initial CORT and β-END responses correlated positively with each other and with the baseline β-END values. Feedback inhibition of CORT secretion with sustained elevation of β-END titres suggests a moderate stress intensity of the repeated blood sampling procedures. In general, due to lack of short-term feedback inhibition, β-END seems to reflect the effects of repeated administration of moderate intense stressors more closely than CORT.
The effects of feeding and housing on the behaviour of the laboratory rabbit
Authors: Krohn T. C. , Ritskes-Hoitinga J. , Svendsen P.
Published: April 2007

The effects of housing, feeding time and diet composition on the behaviour of the laboratory rabbit were examined. The animals were caged individually in single or double metal cages with perforated metal floors, metal walls, and bars in the front, or kept as a group in floor pens. The light/dark cycle was 12/12 h with light from 04:00 to 16:00 hand 30 min twilight. One experiment compared feeding equal energy levels of a high energy diet (10.1 MJ/kg) and with a low energy diet (7.0 MJ/kg) at 08:00 h. The second experiment compared feeding the high energy diet at 08:00 h and at 14:00 h. In both studies the behaviour of the rabbits was recorded between 08:00 and 14:00 h and between 16:00 and 22:00 h. Feeding the animals at 14:00 h reduced abnormal behaviour during the dark period compared to feeding at 08:00 h, whereas no difference in behaviour could be detected between feeding a high-energy and a low-energy diet at 08:00 h. Animals in floor pens generally showed less abnormal behaviour than caged animals. The results indicate that the welfare for caged rabbits can be improved by feeding the animals in the afternoon rather than in the morning.
The telomerase activities in several organs and strains of rats with ageing
Authors: Suzui N. , Yoshimi N. , Kawabata K. , Mori H.
Published: April 2007

Telomerase activity is known to be implicated both in cell immortalization and carcinogenesis. Telomerase activity has not been detected in most human somatic tissues. However, we previously confirmed that the activity is present both in methylazoxymethanol acetate-induced rat colonic adenocarcinoma and non-treated colonic mucosa, presumably indicating the tissue-specific activity of the enzyme in rats. To determine the standard activity of rat telomerase in various organs in relation to differences in sex, age and strain, we examined the activity by using the telomeric repeat amplification protocol (TRAP) assay. The testis, liver, and colon mucosa showed the activity. The brain had very low or negative activity in 5-week-old male rats of the F344, SD, Wistar, Donryu or ACI strains. Age (5-week-old and 9-month-old) or sex difference for the activity was not apparent in rats of these strains. In general, telomerase activity in the fetal brain, liver and kidney was stronger than in the adult organ. The telomerase activity of each organ was different from that of human. This difference may indicate that the rat has a specific mechanism for maintaining the telomeric repeats of the chromosome even in somatic tissues. The basic information resulting from this study may be useful for the study of the role of telomerase in tumorigenesis in animal experiment models.
Pluripotent haemopoietic progenitor cells (CFU-Sd8) in peripheral blood of hereditarily anaemic Belgrade (b/b) rats
Authors: Ivanović Zoran , Milenković Pavle
Published: April 2007

The unique anaemic syndrome of the Belgrade laboratory (b/b) rat is due to an intracellular iron deficiency which is induced by a not yet defined mutation, resulting in impairment of haemopoiesis. We investigated the CFU-Sd8 number and concentration in the peripheral blood of b/b rats to study the relationship between medullary and extramedullary haemopoiesis in this anaemic syndrome. The results show normal concentration of CFU-Sd8 in the peripheral blood of b/b rats. This finding was unexpected in the state of severe anaemia and disturbed growth factor production in b/b rats, where the mobilization of CFU-Sd8 from bone marrow to blood is expected. The results suggest that severe anaemia is not regularly accompanied by the mobilization of pluripotent progenitors from bone marrow to the blood.
Comparison of immunospecific antibody response in young and old chickens immunized with human IgG
Authors: Bollen Lise S. , Hau Jann
Published: April 2007

Three groups of l8-month-old chickens and three groups of 5-month-old chickens were immunized with human immunoglobulin G (IgG) using one of three adjuvants in the first injection (Freund's Complete Adjuvant (FCA), Freunds Incomplete Adjuvant (FIA) and Hunter's TiterMax (HTM)) following the same immunization scheme. The specific antibody response in serum was measured by ELISA. In both older and younger chickens the serum antibody response in the FCA group reached a significantly higher level ( P < 0.01) than in the FIA group and in the HTM group on week 5. The FCA group also had a significantly higher ( P < 0.01) response on week 10 compared to the HTM group. Other than that, there was no significant difference between the three adjuvant groups in specific serum antibody response in older chickens. In the younger chickens the specific serum antibody response in the FCA group was significantly higher ( P < 0.05) than the response in the HTM group. There was no significant difference in the chicken serum antibody response between the FCA and the FIA groups, nor was there a significant difference between the FIA and the HTM groups. Comparing the younger chickens and the older chickens immunized using the same adjuvant, the older chickens had consistently higher titres than the younger chickens, although the difference was not always significant.
Anaesthesia of the common marmoset (Callithrix jacchus) using continuous intravenous infusion of alphaxalone/alphadalone
Authors: Whelan G. , James M. F. , Samson N. A. , Wood N. I.
Published: April 2007

A safe means of anaesthetizing common marmosets ( Callithrix jacchus) for a study using magnetic resonance imaging (MRI) to investigate cerebral ischaemia was required. Continuous infusion of alphaxalone/alphadalone was used to anaesthetize 37 marmosets for non-recovery and recovery experiments. This was found to give safe, reliable anaesthesia when coupled with pulse oximetry and electrocardiographic (ECG) monitoring.
The laryngeal mask airway in experimental pig anaesthesia
Authors: Wemyss-Holden S. A. , Porter K. J. , Baxter P. , Rudkin G. E. , Maddern G. J.
Published: April 2007

The pig is used as a large animal model in many research projects. Standard practice for airway maintenance under general anaesthesia is using endotracheal (ET) intubation after intravenous induction to a near surgical plane. This is a technically demanding skill, requiring the assistance of an experienced technician. A technique is required which simplifies pig anaesthesia. This study examined the feasibility and potential advantages of using the laryngeal mask airway (LMA) in 10 pigs during laparotomy under spontaneous breathing anaesthesia. The results show that the LMA can be inserted rapidly, with minimal time for airway control by researchers relatively inexperienced in anaesthesia and is associated with few complications. By removing the need for intravenous induction, an entire step in the anaesthetic process is removed. The LMA designed for humans fits well in the pig hypopharynx; all pigs could be manually ventilated with no detectable gas leak. Although the pigs in this study were spontaneously breathing it is proposed that the LMA should be further investigated in studies of artificially ventilated pigs.
Methods for exposure of laboratory animals to ultraviolet radiation
Authors: Goettsch Wim , Garssen Johan , de Gruijl Frank R. , Dortant Paul , van Loveren Henk
Published: April 2007

Two different sources of ultraviolet B (UVB) radiation, an electronically controlled UVB exposure unit, containing FS40 tubes, and a hand-held Kromayer lamp, were evaluated for actual irradiance in W/m2 and spectra (physical dosimetry and biological dosimetry (skin effects in rodents)). The technical studies of the FS40 sources demonstrated that the flux intensity of the lamps could be changed electronically, without affecting the spectrum. Thus it was possible to standardize UVB exposure electronically.

The biologically effective doses of these sources were analysed in RIV-Tox Wistar rats and BALB/c mice. After low doses of UVB radiation, histopathological changes such as acanthosis, hyperkeratosis and dermal inflammation were observed in the skin without the presence of major side effects such as erythema and oedema. After higher doses of UVB radiation erythema and oedema were clearly visible. Quantitative studies showed that the minimal erythema dose, as a biological parameter, correlated well to the emission in J/m2. In addition, biological parameters such as acanthosis and inflammation in the skin correlated well to the actual exposure in J/m2 and were sensitive biomarkers for UVB-induced skin toxicity. Thus, in addition to minimal erythemal doses, acanthosis and inflammation may also be applied as biologically relevant doses for studies of the biological effects of UVB radiation.
Induction of anaesthesia with sevoflurane and isoflurane in the rabbit
Authors: Flecknell P. A. , Roughan J. V. , Hedenqvist P.
Published: April 2007

The effects of induction of anaesthesia with sevoflurane and isoflurane were studied in rabbits. All rabbits had periods of apnoea (ranging from 30–180 s) during induction which resulted in moderate hypercapnia and acidosis. Arterial pCO2 rose from 4.1±0.3 kPa to a peak of 7.6±0.4 kPa (mean±SD) (both agents). All animals showed a significant reduction in heart rate ( P < 0.05). Heart rate (HR) fell from 226±33 to a minimum during induction of 57±32 (sevoflurane) and 199±41 to 45±11 (isoflurane). Most animals struggled violently during induction. Use of sevoflurane did not prevent the breath-holding response seen during induction of anaesthesia with other volatile anaesthetics in this species, and the severe apnoea which occurs may represent a significant hazard. The behaviour of the animals indicated that both sevoflurane and isoflurane are aversive, suggesting that this technique should be avoided whenever possible.
Mouse urine collection using clear plastic wrap
Authors: Kurien Biji T. , Scofield R. Hal
Published: April 2007

Qualitative urinalysis using Multistix reagent strips for the detection of urinary pH, protein, glucose, bilirubin, blood, ketone, urobilinogen and creatinine can be carried out with a few drops of mouse urine. The use of metabolic cages is not practical for such qualitative studies particularly when several animals are involved. Here we describe two different methods for collecting pure mouse urine. The single animal method (SAM) involves allowing a single mouse to urinate on Glad® cling wrap outside of the animal cage. The multiple animal method (MAM)involves partitioning seven mice into seven different make-shift compartments laid out on top of the cling wrap and allowing them to urinate. The voided urine, in each case, is then aspirated into micro-centrifuge tubes using a Pipetman. Without coercion pure urine was obtained as early as 12 s. Volumes in the range of 10–250 μl were obtained. Modifications of the SAM could prove useful for rat or mouse urine collection under conditions of microgravity.
A comparison of pre- and post-surgical administration of bupivacaine or buprenorphine following laparotomy in the rat
Authors: Hayes J. H. , Flecknell P. A.
Published: April 2007

The effects of bupivacaine, a long-acting local anaesthetic, and buprenorphine, an opioid analgesic, administered either pre- or post-operatively, were investigated in a rat laparotomy model. Surgical anaesthesia was induced and maintained with halothane. The type of analgesic treatment was a significant factor in the reduction in body weight and food and water intake which occurred following surgery. The largest reductions were seen in the bupivacaine-treated groups and those animals which received no analgesics. The timing of administration of analgesics had no influence on the effect of bupivacaine administration. The group receiving buprenorphine before surgery showed less depression in food intake than the group receiving buprenorphine at the end of surgery. Animals which received buprenorphine showed less depression of activity than those receiving saline or bupivacaine.
EEG evaluation of reflex testing as assessment of depth of pentobarbital anaesthesia in the rat
Authors: Haberham Z. L. , van den Brom W. E. , Venker-van Haagen A. J. , Baumans V. , de Groot H. N. M. , Hellebrekers L. J.
Published: April 2007

Electroencephalography (EEG) was applied to evaluate the validity of the paw pinch reflex as an indicator of anaesthetic depth in rats which are anaesthetized with a single intraperitoneal dose of pentobarbital.

After induction of the anaesthesia, characterized by the rapid loss of the animals' ability to maintain upright posture, the EEG of 10 out of 11 rats was dominated by paroxysmal (burst suppression) activity, associated with unconsciousness. In seven out of 11 rats, the paw pinch reflex was lost after onset of paroxysmal electroencephalographic activity. However, the paw pinch reflex remained present in four out of 11 animals, demonstrating that the response is independent of cortical activity.

In five out of seven rats, the EEG still showed paroxysmal activity when the paw pinch reflex was regained. However, in two other rats the EEG returned to a pattern similar to that shown by awake animals, 4 and 21 min respectively, before the reflex was regained.

These data indicate that in the pentobarbital-anaesthetized rat, presence of the paw pinch reflex is not related to the level of depression of electrical activity in the cerebral cortex, and consequently is probably not related to the level of consciousness. Based upon these findings it is concluded that the paw pinch reflex is unreliable as a sole indicator of anaesthetic depth.
Antidepressants and suicidality
Authors: Lader Malcolm
Published: April 2007

The acceptability of antidepressants among both professionals and the lay public, including depressed patients, has been set back by insistent reports of an enhanced suicidal risk. This encompasses suicidal ideas, intention, attempts and completed acts. Such behaviour is an intrinsic feature of the more depressed individuals and it is difficult to disentangle the risks (or protection) afforded by the use of antidepressants from the background risk.

Clinical trials contain too little data even on meta-analysis to allow firm conclusions, especially with respect to suicide itself. At the other end of the continuum, correlation of prescribing data and suicide data suggests a protective effect of antidepressants, especially the selective serotonin reuptake inhibitors (SSRIs). Other GP databases suggest that a major effect on completed suicide can be ruled out, but that suicidal attempts may be somewhat more frequent in patients taking antidepressants. Against this, other causes of mortality in depressed patients are markedly lower in SSRI-taking patients. An exception is venlafaxine which may be associated with a discernibly enhanced risk, but differential allocation to groups cannot be excluded.

The efficacy of antidepressants in children and adolescents is weaker than in adults, and only significant for fluoxetine. The risks of suicidal behaviour may be increased in this age group; careful choice of medication and close monitoring are essential.

In adults, the suicidal risk should be carefully assessed and patients managed accordingly. They and their carers should be warned of a possible delay in onset of effect. 'Ex-label' use is especially problematic. All in all, the antidepressants have a favourable risk/benefit ratio, but special cases such as children necessitate thoughtful prescribing.