A comparison of intestinal permeability between humans and three common laboratory animals

Intestinal permeability of humans and three species of experimental animals was assessed by the oral administration of the three non-metabolizable sugars: lactulose, rhamnose and mannitol and collecting all the urine produced in a specified time. The total percentage recovery of the permeability markers was determined by high performance liquid chromatographic assays of urinary aliquots. The permeability of the human gut to mannitol was substantially greater than that of rats, guinea pigs, or hamsters (18-, 6- and 29-fold increases, respectively). The permeability to lactulose in humans was somewhat less than that found in guinea pigs (P less than 0.05), but three times greater than that found in rats or hamsters (P less than 0.001). Human rhamnose permeability was substantially greater than that of rats, guinea pigs or hamsters (6-, 2.5-, and 7-fold increases, respectively). The results suggest that the permeability of the human gut to probe molecules is considerably different from that of three common laboratory rodents, but is closest to that of guinea pigs. Possible species differences in the physiological factors which control permeability are discussed.     

On the nonidentity of several carnivore hemoglobins

Antibodies were prepared in rabbits to the hemoglobin of the dog (Canis familiaris). Each of the major adult hemoglobins of several canoid and pinniped species was compared to that of the dog using these antibodies in the micro-complement fixation (MC'F) procedure. Each non-Canis hemoglobin tested reacted less well than that of the dog, and each cross-reaction value was unique. The hypothesis of Seal (1969) of identity of primary structure among these hemoglobins is thus made highly suspect.This research was supported by NSF Grants GB-20750 to the author and GB-13119 to Dr. A. C. Wilson.     

Allometric comparison of recommendations of minimum floor areas for laboratory animals

The recommendations for minimum floor area given in the European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes (1986), as well as in the Publication on the Planning and Structure of Animal Facilities for Institutes Performing Animal Experiments of the Society for Laboratory Animal Science (GV-SOLAS 1989), are plotted in a double logarithmic system in order to get an allometric function of recommended floor area to body weight. Both recommendations correspond very well with the so-called metabolic body weight seen at the allometric exponent of 0.73 and 0.70 respectively. Thus the recommendations in general attribute the floor space according to the metabolic body weight of the animal. Nevertheless, despite this general rule, some species are recommended less space than others when measured on this allometric scale. Thus it must be questioned why, for example, rabbits, chicken and pigs are recommended less space than other species. The general allometric measure seems at least to be a good scale for the comparison of recommended floor space, and for the discussion of species-specific needs for more or less space.     

Evolutionary trends in the hemoglobins of murine animals

The evolutionary origin of murine line based on a phylogenetic tree made on sequence data of ∞-and β-hemoglobin chains, followed by the diversity spectrum of hemoglobin genes in two wild species of murine rodents:Rattus rattus rufescens (house rat) andBandicota indica (bandicoot rat) has been reported. Each house rat contains six hemoglobin types involving two ∞-and three β-chains, which suggests a probable gene duplication at the oc chain locus and a gene triplication at the β-chain locus. Each bandicoot rat contains one ∞-and two β-chains suggesting a probable gene duplication at the β-chain locus. Peptide pattern analysis of the polypeptide chains of these murine hemoglobins further indicates that intraspecies differences among duplicated chains of the same kind are less than interspecies differences among corresponding ∞-and β-chains.     

Pathogenicity for several laboratory animals of toxoplasma oocysts originated from naturally infected cats.

The pathogenicity of four strains, O-1, O-2, O-3, and O-4, of Toxoplasma isolated in the form of oocyst from the feces of naturally infected cats was examined for such laboratory animals as mice, rats, rabbits, guinea pigs, and dogs, in comparison with that of the Beverley strain. Suspensions of seven graded doses of oocysts of each strain ranging from 1.0 X 10(-1) to 1.0 X 10(5) were inoculated orally into seven groups of five mice each. The O-1, O-2, and O-3 strains were as pathogenic for mice as the Beverley strain, but the O-4 strain was not so pathogenic as any other strain. Rats, rabbits, guinea pigs, and dogs were inoculated orally with around 1.0 X 10(5) oocysts. The four O strains were not so severly pathogenic for rats and rabbits as to cause death. The O-2 and O-3 strains showed strong pathogenicity for guinea pigs, almost all of which, when inoculated with them, died after manifesting severe clinical symptoms. The pathogenicity of the O-1 and O-2 strains showed essentially the same tendency for dogs as for any other animal. In inoculation with oocysts, as well as with proliferative forms or cysts, the same pathogenicity was not observed in different strains, even if the same species of host animals was used. On the contrary, the same pathogenicity was not always found even in one strain when a different species of animals was used.     

A comparison of hemoglobins in five species of Microtus

The composition of tryptic peptides was determined for Hb (major or fast electrophoretic component) from four additional species of Microtus; M. p. pennsylvanicus, M. abbreviatus, M. miurus, and M. oeconomus, The amino acids from the four Hb were compared with Hb from M. p. tananaensis, and, on the basis of the combination of analyses for the several Hb. Ca 95% of the overall amino acid composition was considered. The compositions of most of the homologous peptides were identical, and two deletions in the sequence of 21 amino acids β 41–61 are believed to characterize the Hb of all four species. From differences in peptide composition the following substitutions were inferred. In the β chain, M. pennsylvanicus (2 ssp) differed from other species at two positions, 8: Ser vs Thr and 12: Thr vs Ash. In the β chain M. pennsylvanicus (2 ssp) differed from other species at two positions, β45: Phe vs Leu, and β50: Ser-Glx vs Thr. M. p. pennsylvanicus differed from M. p. tananaensis at position β88: Val-Leu vs Leu. All species showed ambiguity among the amino acids Ala-Ser-Phe-Leu centred presumably in positions β129 and β130. On the basis of an incomplete examination, the slow electrophoretic component of M. abbreviatus Hb could not be seen to differ from the fast component in its peptide map or in the general composition of its and β peptides.     

A new airway device for small laboratory animals

There is a need for a device for improved management of the airway of small laboratory animals during general anaesthesia. This report introduces such a device, referred to here as the airway device (AD). The AD has some similarity to the laryngeal mask airway (LMA) developed for human patients, but the mask portion of the device is specifically designed for small laboratory animals. In addition, the device has an oesophageal extension and unlike the LMA does not have a cuff associated with the mask. This report also shares experience of tests of one prototype AD with six New Zealand white rabbits. The AD was used for administering isoflurane and its effectiveness was evaluated during conditions of spontaneous and controlled intermittent positive pressure ventilation. The results provide encouragement for further development of the AD for airway management of small laboratory animals.     

A method for producing forced expirograms in laboratory animals

A method is described for the production of forced expirograms in anaesthetized laboratory animals, using a whole-body plethysmograph and a Hewlett-Packard (HP) 1000-F computer.     

Alphaxolone-alphadolone anaesthesia in laboratory animals

The anaesthetic steroid combination alphaxolone-alphadolone is a well-established short-acting injectable agent for cats and primates. It can be recommended for intravenous administration to rats, rabbits, neonatal pigs, mice and hamsters. It has limited value in mice and hamsters by the intraperitoneal route, but provides sedation in ferrets and neonatal pigs when injected intramuscularly. It can be given repeatedly or continuously to maintain anaesthesia for long periods without the development of tolerance or cumulation.