bluuebunny/crossref_metadata_2025 huggingface dataset:
Contracts and Technology Adoption
Authors: Acemoglu Daron , Antràs Pol , Helpman Elhanan
Published: June 2007

We develop a tractable framework for the analysis of the relationship between contractual incompleteness, technological complementarities, and technology adoption. In our model, a firm chooses its technology and investment levels in contractible activities by suppliers of intermediate inputs. Suppliers then choose investments in noncontractible activities, anticipating payoffs from an ex post bargaining game. We show that greater contractual incompleteness leads to the adoption of less advanced technologies, and that the impact of contractual incompleteness is more pronounced when there is greater complementary among the intermediate inputs. We study a number of applications of the main framework and show that the mechanism proposed in the paper can generate sizable productivity differences across countries with different contracting institutions, and that differences in contracting institutions lead to endogenous comparative advantage differences. (JEL D86, O33)
Leadership and Information
Authors: Komai Mana , Stegeman Mark , Hermalin Benjamin E
Published: June 2007

An organization makes collective decisions through neither markets nor contracts. Instead, rational agents voluntarily choose to follow a leader. In many cases, incentive problems are solved: the unique nondegenerate equilibrium achieves the first best, even though every agent has incentives to free ride. The leader has no special talents but is distinguished by getting exclusive access to information. A crucial feature is that the leader reveals part but not all of her information. It is this maintenance of informational asymmetry that permits achieving the first best. (JEL D23, M54)
Sticky-Price Models and Durable Goods
Authors: Barsky Robert B , House Christopher L , Kimball Miles S
Published: June 2007

The inclusion of a durable goods sector in sticky-price models has strong and unexpected implications. Even if most prices are flexible, a small durable goods sector with sticky prices may be sufficient to make aggregate output react to monetary policy as though most prices were sticky. In contrast, flexibly priced durables with sufficiently long service lives can undo the implications of standard sticky price models. In a limiting case, flexibly priced durables cause monetary policy to have no effect on aggregate output. Our analysis suggests that durable goods prices are the most relevant data for calibrating price rigidity. (JEL E21, E23, E31, E52)
Trust as a Signal of a Social Norm and the Hidden Costs of Incentive Schemes
Authors: Sliwka Dirk
Published: June 2007

An explanation for motivation crowding-out phenomena is developed in a social preferences framework. Besides selfish and fair or altruistic types, a third type of agent is introduced. These “conformists” have social preferences if they believe that sufficiently many of the others do as well. When there is asymmetric information about the distribution of preferences (the “social norm”), the incentive scheme offered or autonomy granted can reveal a principal's beliefs about that norm. High-powered incentives may crowd out motivation as pessimism about the norm is conveyed. But by choosing fixed wages or granting autonomy, trust in a favorable norm may be signaled. (JEL D64, D82, J41, Z13)
A Polymorphic-Cell Sarcoma of The Rat Spinal Cord
Authors: Mawdesley-Thomas L. E.
Published: June 2007

Over the past decade much attention has been paid to comparative neuro-pathology (Innes & Saunders, 1962) but with regard to the small laboratory animal this is still a field for much speculation and further investigation.
Toxoplasmosis
Authors: Fulton J. D.
Published: June 2007

Summary

Toxoplasma is unique among protozoa in its wide distribution and lack of host or tissue specificity. It is a successful parasite in so far as it rarely causes death of the host. The infection is frequently inapparent and this type of infection may be passed from mother to foetus with disastrous results. In domestic animals, it is a cause of serious economic losses, especially among lambs in this country and New Zealand. It may be associated with concomitant infections such as distemper in dogs and helminth infection in cats. In man lymphadenopathy is the commonest clinical manifestation; various affections of the eye and pneumonia also occur. The means of transmission in nature is still unknown apart from the congenital form. It is, however, regarded as a zoonosis and women should take special care where sick animals are concerned. They should be excluded from experimental work on toxoplasmosis. The reaction of the parasite to drugs is unlike that of most protozoa, but curative treatment is possible.
Mycoplasmas and Their Role as Rodent Pathogens
Authors: Fallon R. J.
Published: June 2007

Summary

Mycoplasmas are the smallest known free-living form of life, and differ from bacteria in a number of characteristics. They are widely distributed in the animal kingdom and may give rise to both acute and latent infections as well as being present as normal flora. The three principal rodent pathogens so far described are Mycoplasma pulmonis, Mycoplasma arthritidis and Mycoplasma neuroiyticum. The diseases associated with these organisms are discussed.
The Histology of The Oral Mucosa of Macaca Irus
Authors: Cohen Lawrence
Published: June 2007

Summary

The histology of the oral mucosa of Macaca irus was studied in nineteen monkeys. It was found that the oral mucosa of this monkey is identical with that of man. No single specimen of M. irus had orthokeratinization of the gingivae in all regions. In addition, those sections of gingiva which exhibited orthokeratosis had a poorly developed granular layer. Thus it seems unlikely that keratohyalin granules contribute towards keratinization; they probably represent cytoplasmic debris.
Parasites of Laboratory Animals Transmissible to Man
Authors: Gibson T. E.
Published: June 2007

Summary

An assessment is made of the hazards to man from parasites of laboratory animals. The chief danger arises from gastrointestinal helminths and protozoa of primates and tapeworms of rodents and prevention of infection depends on the adoption of normal hygienic measures for disposal of the faeces and bedding of experimental animals. Simian malaria constitutes a possible danger in those parts of the world where suitable vectors exist and in these areas the screening of animal houses against mosquitoes is necessary. Many ectoparasites of laboratory animals are capable of establishing themselves on human beings but their tenure is usually short. Infestation of man can be prevented only by control of the ectoparasites in the laboratory animals and this is desirable for the welfare of the animals themselves. The possibility of human infection with the parasites of laboratory animals can be greatly reduced by a period of quarantine immediately following arrival, during which examination is made for the presence of parasites and appropriate treatment given to remove any found to be present.
The Establishment of A Specific-Pathogen-Free (SPF) Rat and Mouse Breeding Unit
Authors: Walker A. I. T. , Poppleton W. R. A.
Published: June 2007

Summary

The construction and design of a specific-pathogen-free rat and mouse breeding unit are described. The husbandry and precautions adopted to maintain the pathogen-free status are also discussed.
The Relationship Between A Rodent Mycoplasma, Mycoplasma Pulmonis, and Certain Mycoplasmas Isolated From Tissue Cultures Inoculated with Material from Patients With Leukaemia
Authors: Fallon R. J. , Jackson D. K.
Published: June 2007

Summary

The relationship between Negroni and strain 880 mycoplasmas, isolated from tissue cultures inoculated with material from leukaemic patients, and a rodent pathogen, Mycoplasma polmonis, were studied in detail. The close relationship previously reported between these strains was confirmed but some serological differences were noted. The importance of these differences in the classification of the organisms is discussed.
Rat-Bite Fever in Laboratory Personnel
Authors: Gledhill A. W.
Published: June 2007

Summary

A few cases of rat-bite fever due to Streptobacillus moniliformis have been reported in laboratory workers. Since many laboratory rats carry the aetiological agent in the upper respiratory tract, the opportunity for human infections is high, and undiagnosed infections are probably commoner than is supposed. The symptoms and means of diagnosis of human cases are described, together with a brief account of the infection in laboratory animals. The human disease is also compared with rat-bite fever due to Spirillum minus, which on current evidence appears to be rarer than that due to Streptobacillus moniliformis.
A System of Caging Monkeys
Authors: Coid C. R.
Published: June 2007

Summary

A system of caging monkeys is described in which cages, constructed of aluminium alloy, are suspended over long trays.

Methods of mechanical handling and washing are described as well as a means for making the cages intercommunicating.
A simple apparatus for the inflation fixation of lungs at constant pressure
Authors: Fawell J. K. , Lewis D. J.
Published: June 2007

A simple rapid technique for the uniform inflation of lung prior to fixation is described. The procedure has proved satisfactory for preparation of material for routine quantitative evaluation of experimentally produced emphysema.
A small-animal operating table for use with halothane anaesthetic administered by intubation or inhalation
Authors: Duke D. I. , Clark B. F. , Askill S.
Published: June 2007

An easily manoeuvrable small-animal operating table, to be used in conjunction with halothane anaesthesia, and a method of hypophysectomy in rats under halothane anaesthesia introduced by intubation, are described. The advantages of halothane anaesthesia and animal manoeuvrability in surgical procedures are discussed.
Urine marking of cages and visual isolation as possible sources of error in behavioural studies of small mammals
Authors: Dagg Anne I. , Bell W. L. , Windsor D. E.
Published: June 2007

Chipmunks ( Tamias striatus), jumping mice ( Zapus hudsonius), voles ( Microtus pennsylvanicus), deer mice ( Peromyscus maniculalus), hamsters ( Mesocricetus auratus), house mice ( Mus musculus) and gerbils ( Meriones unguiculalus) were individually confined in dark cages. A corner of each cage had been marked with dried urine. Animals tended (311 of 461 tests) to urinate in the marked corner. Animals did not usually urinate (except adult gerbils) or defecate (except hamsters) in their nests.

The effect of visual isolation of individual mice was not apparent in organ weights, but did lead to altered behaviour.
Cardiovascular response to muscle relaxation in the dog
Authors: Länsimies E. A. , Klossner J. A. , Hirvonen L.
Published: June 2007

The effects of 3 muscle relaxants on the blood circulation were studied in pentobarbitone anaesthetized dogs. Tubocurarine steeply decreased aortic pressure and cardiac output. Pancuronium and succinylcholine had only minor effects upon the haemodynamics. As pancuronium has a longer duration of action it was considered more useful than succinylcholine in experimental work with dogs.
Design of cages and diet for metabolic studies using small new world primates
Authors: Herbert R. T.
Published: June 2007

Metabolic studies using monkeys are difficult. Some of the problems involved are discussed. A stainless-steel cage unit, suitable for metabolic studies using small New World monkeys, is described. The composition and method of preparation of an appropriate pelleted, semi-synthetic diet is also described.
Pseudomonas aeruginosa in rabbit fur
Authors: O'Donoghue P. N. , Whatley Beryl F.
Published: June 2007

Pseudomonas aeruginosa was identified from the fur and skin of rabbits which showed blue-green coat colour and non-suppurative skin sores usually initially in the perianal region. Animals lost condition rapidly and unless treated could die in a few days.
The production of experimental vitamin A deficiency in rats and mice
Authors: Moore T. , Holmes P. D.
Published: June 2007

Vitamin A deficiency in rats and mice was induced by restricting dams and litters from parturition to a pelleted diet made mainly from white flour. Young rats usually developed clear signs of avitaminosis A within 60 days from birth. Mice were more resistant, and some survived for periods up to 150 days from birth. Retention of traces of vitamin A in the liver was no more prolonged in mice than in rats. In mice, enlargement of the prostates and seminal vesicles, and atrophy of the testes, were usually the most prominent pathological features.

In rats, timely treatment with vitamin A acid (retinoic acid) cured xerophthalmia and restored growth. Signs of deficiency reappeared soon after its administration was stopped. This procedure allows supplies of animals to be kept in good general health, but ready for the production of acute deficiency at short notice. Retinoic acid was also effective in curing deficient mice.

Incidental observations on the eyes and reproductive powers of mice or rats dosed with retinoic acid, and on the response of rats to variations in the casein contents of their diet, are recorded.
Urolithiasis in the rat
Authors: Magnusson Göran , Ramsay Carl-Henrik
Published: June 2007

As incidental findings uroliths were observed in the renal pelvis of Sprague-Dawley rats in an 18-month toxicity study. Of 220 rats examined, uroliths were found in 55 (35 males and 20 females). Infrared spectral analysis of the stones indicated a content of ammonium magnesium phosphate. Formation of the uroliths may have started by mineralization of degenerating hyperplastic epithelium of the renal papilla.
Mucosal cysts in the gastrointestinal tract of beagle dogs
Authors: Feron V. J. , Mullink J. W. M. A.
Published: June 2007

Mucosal cysts were observed microscopically in the duodenum, jejunum and, to a lesser extent, stomach and large intestine in 102 out of 236 beagle dogs examined. These dogs were used in toxicity studies or had died spontaneously in a breeding colony. The cysts were lined by intestinal epithelium and filled mainly with cellular debris and mucus. Pathogenesis and aetiology of the lesion are unknown.
Bone marrow biopsy in the rabbit
Authors: Wilson Peter
Published: June 2007

This technique permits repeated bone marrow biopsies in the rabbit. The type of needle and site of biopsy are described in detail, together with the method used to take the sample and eliminate the peripheral blood from it.
Fire-risk-free anaesthesia of rodents with halothane
Authors: Sebesteny A.
Published: June 2007

After 2 serious laboratory fires attributable to the use of ether in animal experimental work, it was decided to promote the use of a non-inflammable anaesthetic. A halothane anaesthetic apparatus of simple design suitable for rodents is described. Previous ether users willingly adopted its use.
Rigid polythene containers for the radiation sterilization of supplies for germ-free animal isolators
Authors: Cook R. , Crook L. J.
Published: June 2007

Commercially available, low-density polyethylene containers were slightly modified so that any 2 of them fitted into a standard cardboard carton suitable for the irradiation plant in this country. Each container was filled with supplies to a total weight of 9.3 kg and, after sterilization by gamma irradiation, was attached to the transfer port of a germ-free isolator. The adoption of these robust airtight containers shortened the time spent on packaging and large quantities of diet and other supplies could be passed into isolators at single entries, so reducing the frequency of entry. The attached containers could also be used for the removal of waste materials.
Life span of specified-pathogen-free (MRC category 4) mice and rats
Authors: Festing M. F. W. , Blackmore D. K.
Published: June 2007

Data are presented on the life span and pathology of 15 inbred and 2 outbred strains of mice, and 1 inbred and 1 outbred strain of rats, maintained under specified-pathogen-free (SPF) conditions. Among the mice, longevity ranged from 312 to 802 days. Survival curves for each strain are given. Neoplasia was the most common pathological finding.
Eradication of tyzzer's disease in a colony of barrier-maintained mice
Authors: Hunter B.
Published: June 2007

An outbreak of Tyzzer's disease in a large mouse colony is described. Tetracycline chemotherapy resulted in the control and apparent eradication of the disease.
Apparatus for collecting faeces and urine from rats in metabolic experiments
Authors: Hansen L. , Holm H.
Published: June 2007

An apparatus, made from ordinary laboratory glass-ware, is described which permits quantitative collection of rat faeces and urine and reduces the possibility of cross-contamination.
Monitoring mouse stocks for lymphocytic choriomeningitis virus-a human pathogen
Authors: Skinner H. H. , Knight E. H.
Published: June 2007

Wild house mice ( Mus musculus) persistently infected with high titres of lymphocytic choriomeningitis virus (tolerant infection) are the source of human inapparent and overt infections, the latter sometimes being of a serious nature. Infections have also occurred in laboratory staff studying the virus and in others handling biological materials contaminated with it. The literature is reviewed.

Great Britain is one of the countries in which pockets of infected wild house mice exist, and these can be a source of infection for laboratory mouse colonies within which congenital transmission through tolerantly infected females would be the main method of spread. Overt signs of the infection may not be detected in mice, and absence of the infection would be certain only if 100% of the litters from which future breeding stock are to be selected were monitored for infectivity and maintained in isolation from unmonitored mice. A suitable monitoring technique is described.

It must be the aim of all breeders of mice to eliminate the possibility of their colonies being a potential hazard to human health. The life-long high infectivity of tolerantly infected mice provides a long-term source of infection for those who handle them and for other biological materials in which the virus can persist without recognition.
An epidemic of chronic skin ulceration in rats
Authors: Ash G. W.
Published: June 2007

An outbreak of chronic skin ulceration in a well-established specified-pathogen-free colony of rats is described. A coagulase-positive staphylococcus was associated with the outbreak, which occurred during winter months and quickly subsided. Various theories are advanced to account for the outbreak, the cause of which was not firmly established.
Lancefield type C streptococcal infections in strain 2 guinea-pigs
Authors: Fraunfelter F. C. , Schmidt R. E. , Beattie R. J. , Garner F. M.
Published: June 2007

Streptococcal infections were diagnosed in a group of strain 2 guinea-pigs. 10 of the animals had cervical lymphadenitis with abscess formation. Other lesions noted were: widespread lymphadenitis, pericarditis, myocardial degeneration, peritonitis, pleuritis, and chronic nephritis. It was not proved that the nephritis was a result of the streptococcal infection, although a relationship was inferred. Chains of gram-positive cocci were seen in lymph nodes and pleural exudate. These organisms were cultured from the exudate and identified serologically as belonging to Lancefield's group C.
Timing of gonadotrophin-induced ovulation and its inhibition in immature mice
Authors: Bell E. T. , Christie D. W. , Parkes M. F.
Published: June 2007

Ova were found in the oviducts of 80% of immature mice at 0400 hours on day 4 following the subcutaneous injection of 5 iu of pregnant-mares' serum gonadotrophin (PMSG) on day 1. When sodium barbitone was administered between 14 30 and 16 00 hours on day 3 the percentage of animals ovulating on day 4 was reduced. Halothane anaesthesia did not inhibit ovulation when given between 08 30 and 17 30 on day 3. Neither anaesthetic altered the mean ovum count.
The effect on rabbit intestinal microflora of diets which influence serum cholesterol levels
Authors: Fuller R. , Moore J. H.
Published: June 2007

The predominant organism in the lower intestine of the rabbit has been characterized and shown to be a Bacteroides sp. Diets which had a marked effect on the plasma cholesterol levels of rabbits failed to produce any detectable changes in the bacteroides population or in any of the other groups of intestinal bacteria examined.
Effect of removing pups when mating lactating rats at the post-partum oestrus
Authors: Kali J. , Amir S. , Morag M.
Published: June 2007

The removal of rat pups from their dams during mating at the post-partum oestrus improved the rate of copulation and increased the number of pregnancies 2-3 fold. A technique for the mating of lactating rats is described.
The Australian scrub wallaby (Wallabia rufogrisea) as a laboratory animal
Authors: Redshaw N. R.
Published: June 2007

Because of its relatively large hind-limb bulk, the Australian scrub wallaby is a useful substitute for man in blood-flow experimentation.

Capture of these wallabies by a simple rope snare, and subsequent housing, caging and feeding are described. Anaesthesia is induced with pentobarbitone sodium and continued with nitrous oxide-oxygen-halothane mixture.
Incidence of congenital abnormalities in a beagle colony
Authors: Marsboom R. , Spruyt J. , Van Ravestyn CH.
Published: June 2007

The incidence and type of congenital abnormalities occurring in a closed beagle colony over a 7-year period is recorded. Examination included 1 360 pups at birth, 758 of which were also autopsied at an age of about 20 months: 9 major abnormalities and 6 cases of cryptorchidism were found, an overall incidence of 1.1%.
Some common parasites of small laboratory animals
Authors: Griffiths Henry J.
Published: June 2007

Some of the more common ectoparasites and endoparasites of small laboratory animals (mouse, rat, guinea-pig, rabbit, hamster, chinchilla and opossum) are reviewed. Guidance is given on identification and control.
Capillaria and Hymenolepis in a wild rat : hazards to barrier-maintained laboratory animals
Authors: Simmons D. J. C. , Walkey M.
Published: June 2007

A wild rat ( Rattus norvegicus) killed in the vicinity of a food store in which pathogen-free animal diet was stored, was found to be heavily infected with Capillaria hepatica and Hymenolepis diminuta. Sacks of diet from the store were found to be contaminated with rodent faeces containing eggs of these parasites. The possibility of Capillaria hepatica eggs infecting animals within a specified-pathogen-free or minimum disease unit and the likelihood of detecting such an infection are discussed. Recommendations are made which would reduce the risk of pathogenic organisms entering an animal unit with the diet.
Physiological and histopathological measurements on lungs of laboratory rats maintained under barrier and under conventional conditions
Authors: Binns R. , Clark G. C. , Healey P.
Published: June 2007

Measurements of goblet-cell activity in the trachea and bronchiolus and of respiratory mechanics were made on colonies of caesarian-derived rats maintained under strict barrier conditions and on animals derived from the same stock but kept under conventional conditions.

It was consistently found over a period of 10 months that no significant changes in goblet-cell activity occurred during a holding period of 6 weeks under conventional conditions. Furthermore, comparison of goblet-cell activity and respiratory mechanics in groups of rats held under barrier and conventional conditions were not significantly different after a holding period of 21 weeks.

It is concluded that for relatively short-term studies, particularly for inhalation work in which these parameters are used to assess irritancy, caesarian-derived rats can be maintained under conventional holding conditions without showing significant spontaneous changes in either structure or mechanical function of the lungs, provided there is no contact with older rats with lung disease.
A simple method for the continuous recording of food consumption in the rat
Authors: Miller A. A. , Soroko F. E.
Published: June 2007

A simple and inexpensive method for the continuous recording of food consumption in the rat is described. The records provide detailed information on eating patterns.
Spontaneous lactation in virgin Sprague-Dawley rats
Authors: Hallowes R. C.
Published: June 2007

Spontaneous milky secretion was found in 24 out of 46 virgin female Sprague-Dawley rats aged 1 year which had been given 30 mg of 9,10-dimethyl-1,2-benzanthracene (DMBA) when 50 days old. The secretory activity was associated with hyperplasia both of mammary epithelium and connective tissue. Additional findings were enlarged adrenals with areas of recent cortical haemorrhage, and ovaries which contained sheets of paraluteal cells. The anterior pituitary of 1 lactating rat contained a small vascular adenoma: no abnormalities were found in the pituitaries of the other animals. It was concluded that these abnormalities could result from increased mammotropic activity of the anterior pituitary.
Spontaneous intussusception of the small intestine in guinea-pigs
Authors: Schoenbaum M. , Klopfer U. , Egyed M. N.
Published: June 2007

A condition is described in guinea-pigs which manifested itself by intussusception of the small intestine in 49 out of 77 fatal cases. Proliferation of the bile ducts and centrilobular fatty degeneration of the liver cells found on histological examination induced us to suspect aflatoxicosis. Toxicological analysis of the lucerne hay fed to the animals corroborated this hypothesis. An organic phosphorous insecticide was also found in the hay.
The management of a small colony of the marsupial Potorous tridactylus, and a record of its breeding in captivity
Authors: Bates P. C. , Bigger T. R. L. , Hulse E. V. , Palmer A.
Published: June 2007

12 Potorous tridactylus were imported from Tasmania and the colony derived from them has been maintained for over 4 years. 4 of the 7 imported females reared young, and animals from this and the next (i.e. second) generation animals have also bred. A total of 38 young have been reared. The 3rd generation is still too young to breed. The young become fertile at 8-11 months and reproductive life can extend for at least 4 years. Only 1 young is produced at a time. Immature young are occasionally ejected from the pouch before they are capable of independent existence.

Potorous tridactylus tends to be nervous and nesting boxes into which they may retreat should always be provided. The animals are best kept in breeding pairs. Adult males kept together in cages may fight.

Details of caging, feeding and handling are given and the method of bleeding for cytogenetic studies is described.
Transmission of Mycoplasma pulmonis between rats
Authors: Hill Auriol
Published: June 2007

Transmission was found to be more rapid from animals showing clinical signs of chronic respiratory disease than from rats with an inapparent experimental upper respiratory infection.
Suppression of aggressive behaviour in the mongolian gerbil, Meriones unguiculatus
Authors: Norris M. L. , Adams C. E.
Published: June 2007

The incidence of fighting was significantly higher in male-male (70%) than in female-male (16%) or female-female (10%) pairings.

The use of a deodorant spray or anaesthesia to overcome aggression was examined. Application of the spray before pairing did not reduce the level of aggression. Anaesthesia before pairing reduced the level of aggression in 83% of pairs, but not in groups of 4 animals. When successfully paired animals were separated for a week and then re-united they again behaved aggressively.

Anaesthesia could have a practical application in the pairing of species that behave aggressively.
Effect of dried baker's yeast and skimmed milk powder on the lifespan of rats
Authors: Dalderup L. M. , Keller G. H. M.
Published: June 2007

The average lifespan of the Wistar strain rats maintained at the Institute was found to be shorter now than it was 20 years ago, particularly in the case of the males. Supplementation of the diet with extra protein (skimmed milk powder or dried yeast) further reduced the lifespan of the males, but increased that of the females.
Effects of insecticides on acariasis in mice
Authors: Constantin M. L.
Published: June 2007

Inbred mice of strains CBA/T6T6, A, C57BL/10Sn and B10.LP were found to be infested in ascending order of severity by Myocoptes musculinus or Myobia musculi mites. All of the 4 insecticidal preparations applied to 5-month-old mice killed the adult stages of Myocoptes musculinus within 2-6 hours, but only 1 was active against Myobia musculi. This latter was 100% active in vitro at 0.5%, but 1% was required in vivo. At 3% it killed 2 of 20 mice, but at 1% it did not interfere with insemination and reproduction, neither did it damage newborn young.
The influence of protein on food consumption in the rat
Authors: Rosen M. , Levinger I. M.
Published: June 2007

Food consumption was compared in male rats offered a free choice between a protein-rich and a protein-poor diet. It was found that the animals grew faster and showed a very strong preference for the protein-rich diet. The preference for the diet was in accordance with the amount of protein necessary for the growth of the animals.
Fixation of rat lungs under physiologically defined conditions
Authors: Egberts J.
Published: June 2007

A simple and inexpensive method for the fixation of expanded rat lungs is described.

Instead of a fixed pressure, the physiologically defined volume has been taken as the better starting point for fixation. Values of this, the maximum lung volume, and the stability index, can be measured.
Hypogammaglobulinaemia and lipaemia initiated by the murine sarcoma virus (Moloney) in rats
Authors: Perk K. , Shachat D. A. , Moloney J. B.
Published: June 2007

Chemical and electrophoretic studies of serum obtained from rats bearing tumours induced by murine sarcoma virus (Moloney) revealed a substantial drop in γ-globulin level and, to a lesser degree, in the albumin level. The α-1 and α-2 globulin fraction levels rose sharply. Also elevated were serum total fatty acids, serum cholesterol levels, lipoprotein (almost entirely associated with the β-lipoprotein and chylomicrons fractions) and the serum glutamic oxalacetic transaminase level.
Accidental contamination of a specified-pathogen-free unit
Authors: Blackmore D. K.
Published: June 2007

The possible routes by which Pasteurella pneumotropica could have gained access to the animals in a strictly barrier-maintained unit, where it established an infection of the upper respiratory tract, are discussed. Details of management before and after the breakdown and the methods of restocking the same building as rapidly as possible with uninfected animals are described.
Rabbit accommodation suitable for long-term experiments in the field
Authors: McSheehy T. W.
Published: June 2007

The design, construction and performance of an integral hutch-run unit suitable for accommodating rabbits under field conditions throughout the year are described.
Incidence of cystic ovaries and reproductive performance in the mongolian gerbil, Meriones unguiculatus
Authors: Norris M. L. , Adams C. E.
Published: June 2007

The incidence and severity of ovarian cysts were stongly age dependent, increasing from 7% in 89 female gerbils aged 135-399 days to 47% in 45 females aged 400-899 days. Cysts varied in size from less than 1 mm up to 50 mm in diameter, and accounted for from 1 to 16% of the female's live weight.

Litter sizes were reduced in the presence of ovarian cysts, and reproduction ceased prematurely. Ovulation and formation of corpora lutea could still occur in cystic ovaries but the proportion of eggs developing normally was reduced from 90 to 29%, probably because of impaired gamete transport.
Respiratory artefact produced by carbon dioxide and pentobarbitone sodium euthanasia in rats
Authors: Fawell J. K. , Thomson C. , Cooke L.
Published: June 2007

Perivascular oedema was observed in the lungs of all rats subjected to carbon dioxide euthanasia. There was also an increased incidence of extravasation of blood compared to that seen in the lungs of rats killed by pentobarbitone sodium.
Maximization of long-term productivity in a rat colony
Authors: Gridgeman N. T. , Taylor J. M.
Published: June 2007

Maximization of intensive breeding in the animal colony can be approached using a simple mathematical treatment of the production-time curve. It has been found that in a colony of specified-pathogen-free albino rats whose breeding dams were averaging litters of 11 at 6-week intervals, the stock should be entirely replaced at intervals of 27-28 weeks to maximize the output of weanlings. Some data on litter size and sex ratio are also presented.
Further studies on induced respiratory viral infection of vervet monkeys (cercopithecus aethiops)
Authors: Martin Gillian V. , Heath R. B.
Published: June 2007

Infection of vervet monkeys with the simian viruses SV5 and SVI7, and an equine rhinovirus, provide useful models of acute respiratory tract disease of man. In these experiments the monkeys were infected with varying concentrations of these viruses. It was found that an inoculum containing a high dose of virus produced a consistent and reproducible pattern of infection, but this was not always achieved when lower doses were used. There was good correlation between the isolation of virus from the respiratory secretions and the development of serum antibody. The selection of an optimum dose of infecting virus, when using these models for the evaluation of antiviral compounds, is discussed.

Quantitative studies of the respiratory secretions produced a flat type of virus growth curve, but the titres were moderately high. The possible value of using this elaboration of the basic test procedure is discussed.
Surgical anaesthesia in conventional and gnotobiotic rats
Authors: Paterson R. C. , Rowe A. H. R.
Published: June 2007

Over 250 rats have been anaesthetised for experimental dental surgery: satisfactory anaesthesia for prolonged surgical procedures has presented some difficulty. A variety of anaesthetic techniques have been used and these are described and their merits discussed.
Lung function and blood gas characteristics in the rhesus monkey
Authors: Binns R. , Clark G. C. , Simpson C. R.
Published: June 2007

Detailed information has been obtained on the normal lung mechanics, lung ventilation and blood gases and pH in unanaesthetized, restrained male and female rhesus monkeys. This information is compared with the limited amount of data previously available on lung function in the rhesus monkey, and with the pulmonary characteristics of the baboon and cynomolgus monkey.
Transmission of Toxoplasma gondil across the guinea-pig placenta
Authors: Wright Ingle
Published: June 2007

6 guinea-pigs were inoculated intraperitoneally at 4-54 days of pregnancy with 60 or 100 Toxoplasma cysts in mouse-brain saline suspension. All foetuses were infected. 3 sows died on 17-19th post-inoculation day, with signs of meningo-encephalitis, and displayed focal lymphocytic inflammation and, in 2, Toxoplasma rosette formation in the cerebral hemisphere. 6 Sows previoulsy inoculated with 100-200 cysts were followed in later pregnancy: 5 of 17 foetuses were found to be infected when delivered-a further 4, and 3 carneous moles, were not examined. 4 non-pregnant sows died at 12-14 days after inoculation with 100-200 cysts, with similar clinical signs to those in the first group.

Antibody titres of 256 were found at 2½ weeks, rising to a maximum of 16 384 at 6 weeks. Levels were consistently falling by 12-14 weeks.

Transmission across the placenta could not wholly be prevented by the presence of antibody except in high titre, and the important factor was concluded to be the parasitaemia.

The strain RB is midway in virulence in guinea-pigs between strains RH and 76.
Automatic weighing of animals
Authors: Walker A. I. T. , Barrett J. W.
Published: June 2007

The use of an automatic weighing system in animal experiments is described. With this system the animal needs to remain still for only 0.5 second; the whole operation of weighing and recording bodyweight and food intake of a rat takes about 16 seconds. The cost of the equipment spread over normal working hours for 5 years is about 5p per hour.
The electrocardiogram (ECG) of the baboon (Papio spp.)
Authors: Osborne Barry E. , Roberts Colin N.
Published: June 2007

6-lead (3 standard, 3 augmented) electrocardiograms were recorded from 150 captured African baboons being used as undosed controls in toxicity studies. The animals, of 14 months to 2 years of age, were unanaesthetised and restrained supine. Analysis of lead II revealed a heart rate of 230±46 beats/min, P-R interval of 0.07±0.02 s, QRS 0.03±0.02 s, Q-T 0.16±0.03 s, and component wave-form amplitudes P (l.6±0.065 mm), Q (0-0.63 mm), R (0-10.44 mm), S (0-5.44 mm), T (0-3.54 mm). The QRS axis was 48±85°.

Deep Q waves were rarely seen preceding an R wave. There: was a conspicuous absence of T wave discordancy in direct contrast to the findings of other workers using anaesthetised animals. No sex differences were seen in any parameter.
Variability of response in cross-fostered rats
Authors: Sharpe R. M. , Morris Audrey , Wyatt A. C. , Brown P. S.
Published: June 2007

The variability of the response to drugs of immature rats bred in natural litters was compared with that of rats cross-fostered into all-male or all-female groups of 9, 12 and 14. The variability of ovarian response to gonadotrophin was significantly greater in naturally-bred animals than in those from cross-fostered litters. There was a suggestion of a similar effect in the variability of barbiturate sleeping time. Variability of seminal vesicle weight, used as an index of response to gonadotrophin in males, did not differ significantly between the cross-fostered and natural litters. Unexpectedly, cross-fostered rats gained more weight in the 4 days after weaning than naturally-bred rats.
Cubed diets of high and low protein values
Authors: Payne P. R. , Stewart R. J. C.
Published: June 2007

Cubed diets have been produced with protein values of 6.8 and 10 net dietary protein-calories per cent. Both diets support reproduction over several generations but the colony maintained on the diet of low protein value has low birth weights, slow rates of growth and small adult size. It is suggested that these diets will enable workers to test for possible adaptations in the physical and mental development of rats and dogs over many generations.
Capture, laboratory care and breeding of elephant-shrews (Macroscelididae)
Authors: Tripp H. R. H.
Published: June 2007

The capture, transport and laboratory maintenance of 3 species of elephant-shrew are described. These animals were kept in order to study their reproductive biology. Pregnant specimens of Elephantulus myurus gave birth in captivity, but captive breeding occurred only in the species E. intufi and Petrodromus tetradactylus. A 4th species ( E. rozeti) was kept for a short period without the occurrence of breeding. Some observations on the development of the young are presented.
Detection of oral papillomatosis in a british rabbit colony
Authors: Mews A. R. , Ritchie J. S. D. , Romero-Mercado C. H. , Scottt G. R.
Published: June 2007

Diagnosis was confirmed by the demonstration of cytoplasmic vacuolation and intranuclear inclusions in epithelial cells, and by observing the virus particles themselves by electron microscopy. Lesions persisted for at least 100 weeks.
Difficulties in the management of Sminthopsis crassicaudata due to iodine deficiency and thyroid disease
Authors: Breckon G. , Hulse E. V.
Published: June 2007

Sminthopsis crassicaudata, imported from a laboratory colony in Australia, originally bred successfully in this country, but 4 months after importation animals began to die with enlarged thyroid glands which were devoid of colloid. Deaths were not prevented until the iodine intake was increased to 60 μg/day. It is possible that this high iodine requirement is in some way related to the mineral content of the soils from whence the animals which formed the nucleus of the Australian colony were obtained.

Spontaneous tumours occur in the species; we observed several animals with uterine polyps and one with a reticulum-cell sarcoma. An X-irradiated animal developed a thyroid carcinoma.
Controlled environment systems for experimental animals II. A unidirectional air flow tent
Authors: Egan B. J. , Butler E. J.
Published: June 2007

A horizontally ventilated tent for housing pathogen-free experimental animals in racks of conventional cages is described. Heating and refrigeration units may be incorporated without structural modification.
Simultaneous measurement of the systolic blood pressure and heart rate in the rat by a transcutaneous method
Authors: Newman D. L. , Looker T.
Published: June 2007

The method described is indirect but atraumatic and can be used with conscious or anaesthetised rats. An occluding cuff is fitted at the base of the tail and pumped up until flow signals from the caudal artery, detected by a Doppler ultrasonic flowmeter, disappear. The cuff pressure at this point corresponds to the systolic pressure. Heart rate and any flow pulse irregularities may be observed at the same time by using a suitable ratemeter and recorder.
Estimation of the foetal age in pregnant rhesus monkeys (Macaca mulatta) by radiography
Authors: Dobbelaar M. J. , Arts T. H. M.
Published: June 2007

A method is described to determine foetal age in the rhesus monkey by means of a roentgenogram of the pregnant mother. A number of anatomical characteristics of the foetus are compared with a series of roentgenograms made on monkeys with known gestation length. Best results were obtained between the 75th and 115th day of gestation, the inaccuracy being ± 5 days.
The importance of platelet function tests in toxicological screening using laboratory animals
Authors: Hawkins Rosemary I.
Published: June 2007

The haemostatic mechanism depends partly upon platelet activity. An increase or decrease in this activity will result in clotting or bleeding abnormalities respectively. Changes of platelet function suggest that an haemorrhagic or thrombo-embolic condition may result from the altered haemostasis induced, for example, by drug or dietary action. It is important therefore that assessment of platelet function is included in normal toxicity screening. In order for this to be carried out it has been established that these tests are applicable to the laboratory animals used for this procedure, and examples given of the typical results obtained.
Ancillary equipment for isolators. 1. A sealed sachet transfer unit
Authors: Egan B. J.
Published: June 2007

An attachment allows waste and other materials, carcases, eggs and equipment to be removed in sealed polythene bags, without risk of contaminating the isolator.
Rabbit renal autografts as an organ preservation model
Authors: Green Colin J.
Published: June 2007

Surgical details are given of a reliable and simple technique for autografting rabbit kidneys which have been preserved by different methods. In a trial series of 20 autografts, 16 rabbits, supported by 1 grafted kidney alone, survived beyond 4 months and were then killed and autopsied. The results are compared with trials using other operative techniques.
The effect of mating female rats at 35 or 80 days of age on pup production and maternal weight
Authors: Kali J. , Amir S.
Published: June 2007

2 groups of 10 rats each were mated for the 1st time at 35 days and 80 days respectively. At 106 days of age the early-mating group had produced 233 pups, whilst the other group had produced 99 pups. Pups produced from the early litters were not smaller than those produced later, but individual litters were smaller. The size of the litter increased with parity. The weight of dams in both groups was similar at 106 days of age.
An inexpensive cooled recirculating system for the maintenance of marine flat fish
Authors: McGregor David
Published: June 2007

Sea water is recirculated, filtered, treated with ultraviolet radiation, and aerated. It is cooled by immersing the tanks in a bath through which cold water from the mains supply is passed. With air temperatures of 18-30°C and mains water at 10-19.5°C, the sea water temperature can be maintained at 18±1.5°C.
A simple device for indirect measurement of blood pressure in mice
Authors: Van Nimwegen CHR. , Van Eijnsbergen B. , Boter J. , Mullink J. W. M. A.
Published: June 2007

The pulsating blood flow in the caudal arteries of anaesthetized mice, detected by means of a photoconductive cell, is interrupted by increasing the pressure in a cuff fixed around the tail. Except for the anaesthetizing, the determination of blood pressures by this method requires little time and training.
Some clinical observations on the eyes of Sprague-Dawley rats
Authors: Heywood R.
Published: June 2007

The eye of the rat shows the main characteristics of all mammalian eyes. The cornea is prominent, and is subject to infection and injury. Age changes were detected in the lenses of a high proportion of rats examined, but cataract did not appear to be a feature of aging of rat lenses. The retina of the albino rat is devoid of pigment, and was subject to destruction of the visual cells by the application of bright light.
Carcinogenicity of wood shavings
Authors: Schoental R.
Published: June 2007

Some 'spontaneous' tumours of laboratory rodents may be due to carcinogenic constituents of wood shavings used as bedding. The recent finding that the p-0-methyl derivative of sinapaldehyde and 2,6-dimethoxy-1,4-benzoquinone are carcinogenic for the rat may implicate the α, β-unsaturated carbonyl compounds present in wood lignins.
The GH and AS hypertensive rat strains
Authors: Heslop Barbara F. , Phelan E. L.
Published: June 2007

The origin of 3 inbred albino rat strains, AS, AS2 and OH, is traced from the same random-bred albino colony. Both the AS and OR strains are hypertensive, while the AS2 strain and the random-bred albino rats are normotensive. The OH breeders have been routinely selected for high blood pressure, while AS breeders are selected for intrastrain histocompatibility. It is highly likely that AS originated as a subline of OR in 1960. The AS and OR strains have been maintained separately since 1960, and the blood pressure is currently higher in OR than in AS.
The effect of repeated cisternal puncture and withdrawal of cerebro-spinal fluid in the dog
Authors: Heywood R. , Osborne B. E. , Street A. E.
Published: June 2007

The only change in the constituents of the cerebra-spinal fluid recorded after 10 punctures of the cisterna magna, with replacement of the fluid by physiological saline, was a slight decrease in the glucose values.
Ancillary equipment for isolators. 3. A device for the collection of blood samples externally
Authors: Egan B. J.
Published: June 2007

Blood samples are collected from fowls by cardiac puncture through a self-sealing septum, thereby avoiding the transfer of equipment and samples to and from the isolator.
The effect of the sex of litter-mates on the subsequent behaviour and breeding performance of cross-fostered rats
Authors: Sharpe R. M. , Morris Audrey , Wyatt A. C.
Published: June 2007

The response to drugs, the reaction to handling, and the breeding performance of rats bred in unisexual and in bisexual cross-fostered litters were compared. There was no significant difference in their response to drugs, although bisexually-reared animals consistently gave a more precise dose-response line to gonadotrophin. When handled unisexually-reared males defaecated more frequently and squeaked more loudly than bisexually-reared males, a difference not evident in the females. The rate of attainment of sexual maturity was similar in both rearing types but, when mated, bisexually-reared females produced larger litters.
Ancillary equipment for isolators. 2. A food transfer unit
Authors: Egan B. J.
Published: June 2007

Because it is operated from outside the isolator, and sterilization is simpler, this hermetically-sealed food-transfer attachment is more convenient to use than transfer ports or sleeves.