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Objective: Monitor the ameliorative impact of Nigella sativa on fasting blood glucose and serum testosterone levels in polycystic ovarian syndrome caused by letrozole in mice. Study Design: Laboratory based randomized control trial. Place and Duration of Study: Anatomy department, Army Medical College in teamwork with National Institute of Health. Time span is Dec 2014 Dec 2015. Methodology: Total 40 mature female BALB/c mice were chosen and distributed in four groups (ten mice in each one). Group 1 was given normal diet. Rests of three groups were treated with Letrozole at dose of 1 mg/kg body weight once daily for eight weeks. Group 3 was also given Nigella sativa seeds powder at dose of 10 g/kg body weight once daily starting at 22 day and continued up to eight weeks. Group 4 was treated with Nigella sativa oil at a dose of 4 ml/kg body weight once daily starting at 22 day and continued up to eight weeks. At termination of trial, fasting blood glucose level (FBG) was recorded by taking blood sample by glucometer from mouse lateral tail vein after 12 hours fasting. Mice with blood glucose level 250-464 mg/dl were marked hyperglycemic. Final blood sample was taken through cardiac puncture for serum testosterone evaluation. Results: Fasting blood glucose and Serum testosterone levels were raised in group 2 animals in comparison to group 1 while they were reduced remarkably in group 3 and 4 in comparison of group 2. Conclusion: Nigella sativa seeds in both solid and liquid state leave an identical curative impact on fasting blood glucose and serum testosterone levels in polycystic ovarian syndrome in mice.

Background: The rat femoral vein and dorsal penile vein have been have been well described as microvenous models. We report the use of the rat tail lateral vein as model for microvenous anastomosis training. Methods: Careful anatomic dissections were made of the rat tail noting the basic gross anatomy in 3 rats. 20 albino rats were anaesthesized via intraperitoneal ketamine injection, lateral vein of the tail is then transected about 5 cm distal to the tail base. Immediate repair was carried out by standard interrupted microanastomosis suture technique with 10/0 nylon suture. Patency was assessed at 30 minutes and 1 week. Results: 40 consecutive anastomosis of the lateral tail vein was done in 20 rats . The mean diameter of the rat tail lateral vein in the study rats was 0.8mm SD± 0.02mm.The mean anastomosis time was 22.6 minutes SD±4.3 minutes from clamp application to removal. There was a 90% patency rate at 30 minutes and 81 % at 1 week. Conclusion: The rat lateral tail vein appears to be a viable alternate model for microvenous anastomosis. The study identifies the ease of access, duality, potentially long length and the absence of accompanying artery as some of the unique features of this microvenous anastomosis practice model. [Hand Microsurg 2020; 9(3.000): 177-180]

Tail bleeding models are important tools in hemophilia research, specifically for the assessment of procoagulant effects. The tail vein transection (TVT) survival model has been preferred in many settings due to sensitivity to clinically relevant doses of FVIII, whereas other established models, such as the tail clip model, require higher levels of procoagulant compounds. To avoid using survival as an endpoint, we developed a TVT model establishing blood loss and bleeding time as endpoints and full anesthesia during the entire experiment. Briefly, anesthetized mice are positioned with the tail submerged in temperate saline (37°C) and dosed with the test compound in the right lateral tail vein. After 5 min, the left lateral tail vein is transected using a template guide, the tail is returned to the saline, and all bleeding episodes are monitored and recorded for 40 min while collecting the blood. If no bleeding occurs at 10 min, 20 min, or 30 min post-injury, the clot is challenged gently by wiping the cut twice with a wet gauze swab. After 40 min, blood loss is quantified by the amount of hemoglobin bled into the saline. This fast and relatively simple procedure results in consistent and reproducible bleeds. Compared to the TVT survival model, it uses a more humane procedure without compromising sensitivity to pharmacological intervention. Furthermore, it is possible to use both genders, reducing the total number of animals that need to be bred, in adherence with the principles of 3R's. A potential limitation in bleeding models is the stochastic nature of hemostasis, which can reduce the reproducibility of the model. To counter this, manual clot disruption ensures that the clot is challenged during monitoring, preventing primary (platelet) hemostasis from stopping bleeding. This addition to the catalog of bleeding injury models provides an option to characterize procoagulant effects in a standardized and humane manner.

Doxorubicin-induced nephropathy in mice is a model for studying experimental nephrotic syndrome. It corresponds to puromycin aminonucleoside nephrosis in rats. In this model, susceptible 129 S1/SvImJ mice are administered a rapid intravenous injection that can be accomplished via either the lateral tail vein or the retrobulbar sinus. Because doxorubicin is a highly toxic substance, extravasation must be avoided during the administration of the intravenous injection to prevent the development of large necrotizing lesions and exacerbation of the animals’ stress. In the present study, we compared the safety and stress of these two injection routes by using histopathological analyses of the animals’ orbital cavities or tails, respectively. The injection of 14.5 µg/g body weight doxorubicin into the mice’s lateral tail veins ( n = 9) or retrobulbar sinuses ( n = 19) caused no clinically detectable stress or impairment. Histopathologies of the specimens five days after doxorubicin injection revealed inflammatory lesions at the injection sites in both groups. In the orbital sinus specimens from the retrobulbar-injected group, fibrosis was evident 25 days after injection. Moreover, while all of the retrobulbar-injected mice (100%) developed nephrotic syndrome, tail vein-injected mice had a significantly lower response rate (66%, p = 0.047, Fisher’s exact test) and exhibited only attenuated features of nephrotic syndrome. It was therefore concluded that doxorubicin administration via either lateral tail vein or retrobulbar sinus injections led to a similar induction of histopathological changes with no effects on the clinical well-being of the mice. However, retrobulbar sinus injections were more efficient for inducing experimental nephrotic syndrome.

Compounds and products in the biocide and plant protection sector can only be registered after formal risk assessment to ensure safety for users and the environment. In bird and mammal risk assessment, this is routinely done using generic focal species as models, which are of particular exposure risk. Such a species is the common vole (Microtus arvalis) due to its high food intake relative to the low body weight. For wild species, biological samples, data and hence realistic exposure estimations are particularly difficult to obtain. In recent years, advances have been made in the techniques related to serial microsampling of laboratory mice and rats that allow for a reduction in sampling volumes. Similar progress in wild species sampling is missing. This study presents a proof of concept to dose wild rodents with relevant compounds and to draw serial, low volume blood samples suitable for state-of-the art toxicokinetic analyses. For the first time, the jugular vein of common voles was used to administer compounds (two frequently used fungicidal components). This procedure and the following microsampling of blood (2 × 10 μl six times within 24 hours) from the lateral tail vein did not affect body weight and mortality of voles. Samples were sufficient to detect dissipation patterns of the compounds from blood in toxicokinetic analysis. These results suggest that microsampling can be well translated from laboratory mice to wild rodent species and help to obtain realistic exposure estimates in wild rodents for ecotoxicological studies as well as to promote the 3R concept in studies with wild rodent species.

BACKGROUND The still maturing adolescent brain may be particularly vulnerable to lasting consequences of ethanol (EtOH) exposure. Yet, human adolescents are the age group most likely to engage in binge drinking (a pattern of drinking leading to blood EtOH concentrations (BECs) of 80 mg/dl or greater). Most studies to date assessing the long-term effects of adolescent EtOH exposure in outbred rodent populations have either used experimenter-administered EtOH to produce BECs in the binge range or assessed voluntary intake of EtOH at well below binge levels. Beginning with a modified schedule-induced polydipsia (SIP) procedure, this study examined the suitability of several approaches to induce voluntary binge-like consumption during adolescence in an outbred rat strain. METHODS Adolescent male and female Sprague Dawley rats were food deprived to 85% projected free-feeding weights beginning on postnatal day (P) 24 and were given 30 minutes of access to 10% EtOH in chocolate Boost® or Boost® alone daily from P28 to P41 (followed later by their daily allocation of food). Animals were tested within operant chambers (Exp. 1a, 1b and Exp. 2) or home and novel cages (Exp. 3). Animals received either scheduled delivery of banana pellets to examine SIP (Exp. 1a,b) or massed pellet presentation (Exp. 2 and Exp. 3). Blood samples were collected via the lateral tail vein on P33 and P41. RESULTS Intakes produced BECs frequently in the binge range (>80 mg/dl) and modeled binge-like consumption patterns, with high consumption days typically followed by 1 to 2 days of lower consumption; this variability was less evident with Boost® alone. Consumption was not schedule induced and was generally high across all studies, although consumption in males appeared to be particularly pronounced when animals were tested in the presence of their cage mate. CONCLUSIONS Binge-like patterns of EtOH consumption were produced using these procedures in adolescent Sprague Dawley rats of both sexes and may prove to be a useful model for work examining the short- and long-term consequences of high levels of voluntary EtOH intake in adolescence.

Intravenous (IV) administration of agents into the tail vein of rats can be both difficult and inconsistent. Optimizing tail vein injections is a key part of many experimental procedures where reagents need to be introduced directly into the bloodstream. Unwittingly, the injection can be subcutaneous, possibly altering the scientific outcomes. Utilizing a nanoemulsion-based biological probe with an incorporated near-infrared fluorescent (NIRF) dye, this method offers the capability of imaging a successful tail vein injection in vivo. With the use of a NIRF imager, images are taken before and after the injection of the agent. An acceptable IV injection is then qualitatively or quantitatively determined based on the intensity of the NIRF signal at the site of injection.

BACKGROUND Age- and gender-related alterations of hemorheological parameters have not been completely elucidated to date. Experiments on older animals may give valuable information on this issue. However, the majority of rheological studies have been performed in young rodents. OBJECTIVE We aimed to investigate the influence of aging and gender on hemorheological parameters in rats. METHODS Coeval male (n=10) and female (n=10) Wistar (Crl:WI) rats were followed-up over 15 months. Blood samples were obtained from the lateral tail vein at 3, 4, 5, 9, 12, 15 and 18 months of age. Hematological parameters, red blood cell deformability (elongation under shear), osmotic gradient deformability and erythrocyte aggregation were tested. Body weight and the estrus cycle (in females) were also examined. RESULTS Erythrocyte aggregation showed age- and gender-related variations. Red blood cell deformability was greater in females and gradually decreased over the 15-month period in both genders. Erythrocyte aggregation was greater in male rats at most ages, but did not show consistent changes with age. CONCLUSIONS The micro-rheological parameters showed age-related alterations with gender differences. The effect of the estrous cycle cannot be excluded in female rats. The results provide reference data for studies of aging in rats and of the mechanism related to age and gender differences in hemorheology.

Passiflora foetida leaves used by the society for generations as a natural antidiabetic drug research aims to test the effectiveness of the leaf extract of Passiflora foetida with variations of a dose of 250 mg / kg, 500 mg / kg, and 750 mg / kg in lowering blood sugar levels in mice. Passiflora foetida leaves were extracted by sokhletasi method with 70% ethanol, the extract was tested on 15 mice, the test animals were randomized into 5 groups consist of negative control group given 0.5% Na-CMC, positive control group was given glibenclamide 0, 65 mg / kg, and the treatment group were given the leaf extract of Passiflorafoetida with variations of each dose of 250 mg / kg, 500 mg / kg, 750 mg / kg. To increase blood sugar levels in mice induced glucose 50%. Measurement of blood sugar levels in mice were performed using an easy touch glucometer and blood is taken via the lateral tail vein. The results showed that the percentage of blood sugar levels drop to a negative control is 13.1%, for a dose of 250 mg / kg body weight of 29.52%, for a dose of 500 mg / kg was 38.79%, to dosis750 mg / kg was 49, 21%, and 48.1% for the positive control. The results showed that the leaf extract of Passiflorafoetida at a dose of 750 mg / kg is most effective as an antidiabetic

Objective To investigate a topical local anesthesia technique as a means to prevent and/or diminish pain in mice in a laboratory setting associated with tail vein injections performed by personnel in training. Study design Prospective, randomized experimental trial. Animals Thirty six adult female, 23–28 g CD-1 mice from an in-house training colony. They were acclimated to routine training and handling classes. Methods Eutectic mixture of local anesthetics (EMLA) cream (2.5% lidocaine/2.5% prilocaine) or a bland ointment control (n = 18) was applied on the tail prior to intravenous injection. The injections were performed by novices, who had never attempted the procedure, and experienced personnel. All participants were blinded to treatment groups. Three injection attempts were allowed per animal. The mice were observed and scored by blinded evaluators for behavioral and physiological changes, including respiratory rate, vocalization, tail flick, and escape behaviors, during and after the injection. Results This study demonstrates that aversive behaviors induced by lateral tail vein injection were not changed by the preemptive application of EMLA cream. The aversive behaviors associated with lateral tail vein injection were significantly affected by the number of injection attempts and the individual's experience level. Conclusions and clinical relevance Topical EMLA cream did not reduce signs of aversive reaction to tail vein injection and thus we did not find support for its use in mouse training programs for tail vein injections.

Much evidence indicates that bacterial LPS (endotoxin) is removed from the bloodstream mainly by the liver, yet the hepatic uptake mechanisms remain uncertain and controversial. In plasma, LPS can be either ‘free’ (as aggregates, bacterial membrane fragments or loosely bound to albumin, CD14, or other proteins) or ‘bound’ (complexed with lipoproteins). Whereas most free LPS is taken up by Kupffer cells (KCs), lipoprotein-bound LPS has seemed to be cleared principally by hepatocytes. Here, we compared the liver’s ability to take up and deacylate free LPS aggregates and the LPS in preformed LPS-high density lipoprotein (HDL) complexes. In mice examined from 1 h to 7 d after a small amount of fluorescent (FITC-)LPS was injected into a lateral tail vein, we found FITC-LPS almost entirely within, or adjacent to, KCs. As expected, FITC-LPS complexed with HDL (FITC-LPS-HDL) disappeared more slowly from the circulation and a smaller fraction of the injected dose of FITC-LPS was found in the liver. Unexpectedly, the FITC-LPS injected as FITC-LPS-HDL complexes was also found within sinusoids, adjacent to, or within, KCs. In other experiments, we found that both free and HDL-bound radiolabeled LPS underwent enzymatic deacylation by acyloxyacyl hydrolase (AOAH), the LPS-inactivating enzyme that is principally produced within the liver by KCs. Our observations suggest that KCs and AOAH play important roles in clearing and catabolizing both free LPS and the LPS in circulating LPS-HDL complexes.

We have developed two murine models of disseminated infections by Neoscytalidium dimidiatum, an emerging dematiaceous fungus. Immunosuppressed mice were challenged through the lateral tail vein with 1 x 10(5) or 1 x 10(6) CFU/ml and immunocompetent animals with 1 x 10(6) or 1 x 10(7) CFU/ml. N. dimidiatum var. dimidiatum was more virulent than the nonpigmented variety, N. dimidiatum var. hyalinum. All mice infected with N. dimidiatum var. dimidiatum died within 8 days while those infected with N. dimidiatum var. hyalinum survived to the end of the experiment. Fungal load in tissue was also higher in animals inoculated with N. dimidiatum var. dimidiatum. In general, of the five organs tested, spleens and kidneys were most affected.

1. In anaesthetized rats, using a focal recording technique, activity was recorded from single sympathetic postganglionic neurones innervating the lateral tail veins. On-going activity was examined in order to determine whether it had similar or different characteristics to those recorded from the caudal ventral artery in a previous study. 2. Animals were artificially ventilated, vagotomized, paralysed and given a pneumothorax. 3. The discharges of fourteen out of seventeen sympathetic postganglionic neurones were rhythmic. Such units had a mean firing frequency of 1.62 +/- 0. 70 Hz. The mean frequency of the dominant sympathetic rhythm under control conditions was 0.82 +/- 0.05 Hz. 4. The frequency of the dominant sympathetic rhythm was different from that of the phrenic rhythm in nine out of fourteen cases. 5. The mean frequency of the dominant sympathetic rhythm was: (i) not influenced significantly by hypocapnic apnoea, (ii) decreased by hyperthermia, which increased the frequency of the phrenic rhythm, (iii) in all cases different from that of the artificial ventilation cycle. 6. The above characteristics are similar to those recorded from the sympathetic supply to the caudal ventral artery of the same vascular bed under comparable conditions.

In pharmacokinetic studies, intravenous (i.v.) administration of antibodies to mice is usually done via the lateral tail vein. This approach can cause stress to the mice and has a high rate of failure because it is challenging to perform correctly. Administration via the retro-orbital venous sinus has been suggested as a good alternative to tail vein i.v. administration of antibodies. Evidence is still needed, however, to determine whether the route of administration has an effect on the absorption or the pharmacokinetic activity of the injected antibody. The authors compared serum concentrations and pharmacokinetic parameters of a therapeutic antibody administered via tail vein injection or via retro-orbital injection. The findings suggest that there is no difference in the absorption or pharmacokinetic activity of therapeutic antibodies when administered via the lateral tail vein versus the retro-orbital venous sinus.

PURPOSE To evaluate "bolus-tracking" (BT) and "flash-replenishment" (FR) for the assessment of tissue hemodynamics by contrast-enhanced ultrasound (CEUS) in an experimental small-animal-squamous-cell-carcinoma-model. Since the underlying tissue is the same, strong correlations between parameter outcomes of both techniques are expected. METHODS AND MATERIALS Human hypopharynx-carcinoma-cells were subcutaneously injected into the left flank of 18 female athymic-nude-rats. After 10 days of subcutaneous tumour growth, bolus tracking and flash-replenishment measurements were performed consecutively in the same imaging plane in each rat after bolus-injection of SonoVue via the lateral tail vein using a high-end ultrasound system with a 15 MHz probe. Video-sequences were analysed with dedicated software (VueBox®, Bracco-Suisse®). From BT measurements, the parameters peak enhancement (PEBT), wash-in area-under-the-curve (Wi-AUCBT), mean transit time (MTTBT), wash-in-rate (WiRBT) and perfusion-index (Wi-PIBT) were derived; FR yielded estimates of relative-blood-volume (rBVFR), mean transit time MTTFR, relative blood flow rBFFR and wash-in rate Wi-RFR. RESULTS In all rats, BT and FR measurements could be completed successfully. Highly significant correlations were observed between rBVFR and PEBT, rBVFR and Wi-AUCBT, rBVFR and MTTBT, rBVFR and WiPIBT, MTTFR and MTTBT, rBFFR and PEBT, rBFFR and Wi-AUCBT, rBFFR and WiRBT, rBFFR and WiPIBT, WiRFR and PEBT, WiRFR and Wi-AUCBT, WiRFR and WiRBT and WiRFR and WiPIBT. CONCLUSION Whereas bolus tracking can be used in a wide range of modalities including CEUS, CT and MR, FR as a technique for the assessment of tissue hemodynamics is unique to CEUS. Although BT and FR yield different parameters, the underlying tissue hemodynamics are equal. In this work, we were able to demonstrate strong correlations between different parameters of both modalities in a small-animal-tumor-model, indicating that flash-replenishment is a valid alternative to the more established bolus-tracking technique. Although the lack of absolute, quantitative parameters hinders a direct comparison of both modalities, FR and BT should both be suitable for a relative comparison, e.g. between baseline and follow-up examinations.

It is known that hemorheological parameters show gender differences that might be altered by gonadectomy (GoE). Since micro-rheological parameters (erythrocyte deformability and aggregation) sensitively change during and after ischemia- reperfusion (I/R), the question arises whether the hemorheological effects of I/R may show gender differences and further changes might be expected when GoE and I/R are additive. Sprague-Dawley rats were divided into six groups: Control males and females, I/R males and females with 1-hour hind limb ischemia, GoE + I//R males and females when 3 months after bilateral gonadectomy the I/R was induced. Before and just after ischemia, and on the 1st-3rd-5th-7th postoperative days blood samples were taken (lateral tail vein, 0.3-0.5 mL) for analyzing hematological parameters, erythrocyte's deformability (slit-flow ektacytometer) and aggregation (light-transmission aggregometer). Leukocyte and platelet counts raised markedly in gonadectomized animals during the investigated days. Hemorheological changes of I/R showed gender differences: significant impairment of erythrocyte deformability was found on the 1st-3rd postoperative days, expressed mostly in females. In gonadectomized females the postischemic deformability values were impaired. Erythrocyte aggregation index significantly raised by the 1st postoperative day, dominantly in males. It is suggested that gonadectomy may act as an additional rheological 'risk factor' related to blood micro-rheological parameters in ischemia-reperfusion.

Epidemiologica! studies have suggested that cotton textile workers exhibit lower than expected rates of cancer, in particular, lung cancer. An animal model using aerosolized cotton dust as a treatment was used to evaluate and substantiate reported epidemiological results. Mice were injected in a lateral tail vein with 1 x 105 viable Lewis lung carcinoma cells and treated with aerosolized cotton or inert (cellulose) dust. The results suggest that animals that inhale cotton dust after injection with tumor cells survive longer than control animals. Animals treated similarly with inert (cellulose) dust survived just as long statistically as the group treated with cotton dust. This supports the hypothesis that some beneficial effects are derived from occupational exposure to cotton dust. Occupational exposure to other kinds of dust may also be beneficial, but the results are masked by confounding variables. It is hypothesized that a common containment of dust, endotoxin, is responsible for this benefit.

Newly formulated cationic liposomes (TRX-liposomes) with four different mean diameters were injected into twelve male rats via the lateral tail vein in order to evaluate the effect of liposomal size on pharmacokinetic parameters. TRX-liposomes disappeared from the blood according to the one-compartment model and demonstrated maximum and minimum half-lives of ca. 14 h (mean diameter of 114.3 nm) and ca. 5 h (mean diameter of 285.9 nm), respectively. This prolonged half-life tended to decrease at the boundary of 114.3 nm mean diameter. The optimal size (114.3 nm) for prolonged circulation of TRX-liposomes was consistent with that of pegylated liposomes such as Doxil((R)), however, the half-life was different among these liposomes. The electric charge of the TRX-liposomal surface is assumed to be responsible for this difference. The results of the present study will be very useful in the design of long-circulating cationic liposomes.

A lateral tail vein of the rat is used as the route for continuous infusion. The animal is kept under neuroleptic tranquilisation during the infusion.

The technique of blood collection from the lateral caudal vein has been improved. The method requires only moderate skill and no anaesthesia is necessary. Collection of blood samples causes little trauma and can be repeated at frequent (8 h) intervals thus making the method particularly suitable for pharmacokinetic and hormonal studies. Blood samples are uncontaminated by tissue fluids. Large volumes can be obtained, in mice up to 1·5 ml and in Wistar rats over 4 ml.

Rats were injected in the lateral tail vein with 2, 4, 8, 12 or 16% NaCl solutions and were immediately placed in drinking ☐es where water intake was measured for 2 hr. Injections were 1 or 2 ml/400 g body weight. Drinking increased as a function of load volume and concentration. Another group of rats received identical injections, were decapitated 10 min after injection, and serum samples were obtained for analysis in an osmometer. Osmometric equations were applied to determine the theoretical and apparent cell dehydration which followed injections. Drinking appeared to be correlated with calculated cell dehydration. Drinking occurs in the rat following shrinkage in cell volume as small as 1%.

In this paper consideration will be given to the transport of metabolizeable molecules and their transformation once they have entered the brain from the blood. Few studies on uptake processes have also followed the rapidity with which some substances can be transformed by established enzymic pathways. Furthermore, even substrates undergoing certain metabolic sequences in common, such as the formation and oxidation of acetyl-CoA, appear to do so in a non-uniform manner. This may indicate a “directed” movement of small molecules to specific sites for metabolism. This could be into particular types of cells or into discrete parts of the same cell type.

Mice have several properties which make them ideal subjects for studying the effect of drugs on the reward process. They are compact, inexpensive, and available in strains which vary in number of dopamine receptors, opiate receptors, or sensitivity to alcohol. Mice can be lightly restrained by taping their tails to the floor thereby allowing electrical or chemical stimulation of the brain without the use of swivel connectors or commutators. Intravenous injections can be made through a lateral tail vein while the animal is restrained and is free to emit operants. This chapter describes these techniques and suggests some pitfalls to avoid.

Summary A simple, reliable and economic alternative for those who find previously described methods unsatisfactory. Intravenous infusions of therapeutic agents, radioisotopes or simple crystalloid solutions are often needed in experimental animals, requiring either severe restraint of the animals or the application of a protective device. Close restraint is ethically undesirable, and in rats causes acute gastric erosions (Sonftls, Richir, Potet, Liefooghe & Lambling, 1959). Tail veins commonly provide a site of infusion in mice and small rats, but in rats heavier than 200 g the thick, horny tail skin renders this extremely difficult to achieve without surgical exposure of the lateral tail vein prior to cannulation. Since the emergence of the cannula from the tail facilitates the application of a protective device and allows the rat relative freedom of movement, we have developed a technique in which a nylon cannula is passed through a subcutaneous tunnel from tail to left thigh, where its tip is inserted and tied into the femoral vein.

Repeated blood sampling from laboratory animals is desirable in certain experimental designs and also for reducing the number of animals used in research. Biochemical methods for analysing blood samples require only small blood volumes to be collected (typically 20–40 µL). In juvenile mice, the small blood volume of the animals also requires only small samples to be taken. Furthermore, for behavioural studies it is desirable to have a method that does not require anaesthesia or the use of invasive indwelling cannulae. We report the validation of a refined method for repeated blood sampling (up to 3 times at 24 h intervals) in juvenile and adult mice using the tail incision method to sample from the lateral tail vein. This method is not stressful, as assessed by low basal levels of the stress hormone corticosterone. Since repeated blood samples can be collected from the same animal at multiple time points, it is not necessary to increase group size for terminal sample collection. Thus, in addition to being a refined method requiring no warming of the tail, no anaesthesia and only gentle restraint, this method also reduces the numbers of mice used for experiments.

with cysticercoids or live worms releasing no or few eggs. This result is interesting in view of previous observations that H. nana successively changes its immunogenicity during development (Ito, 1980, Exp. Parasitol. 49: 248-257; Ito, 1982, Exp. Parasitol. 54:113-120; Kano and Ito, 1983, Jap. J. Parasitol. 32: 183-193). A similar experiment was done using 10 male ICR mice that were dosed orally with 100 shellfree eggs and bled from the lateral tail vein every 10 days from day 0 to day 70. The IgG antibody was detected by DD in >40-day sera, and reached a plateau at a titer of 1:16 in > 50-day leasi o or i i ie of . a s ccessi el i i e elo e t . : ; Ito, 1982, ; It , 1983, sera. IgE was detected in > 30-day sera and the antibody levels reached a peak (1: 320) at 60 days of infection. This suggests that there may be strain differences in the antibody responses against H. nana infections in mice. This work was supported in part by Scientific Research Grant (no. 56770230, 1981) from the Ministry of Education of Japan. The author thanks Dr. G. F. Mitchell, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia, for his critical comments on this pa