Peritoneal dialysis in small laboratory animals

Healthy rats and guinea-pigs were treated with a simple method of continuous peritoneal dialysis for 12, 24 and 48 h. Increasing with time, both animal species developed severe hypoproteinemia and hemoconcentration due to protein loss into the dialyzate fluid. These changes were associated with a high mortality rate, when Sterofundin was used for dialysis. Therefore, protein loss should be substituted and the type of dialyzate must be considered in experimental long-term dialysis using these small laboratory animals.     

Propoxyphene: pathways of metabolism in man and laboratory animals

Through the combined use of stable isotope labeling and gas chromatographic mass spectrometric analysis, the metabolic patterns for propoxyphene have been determined in laboratory animals and man. The rat and dog eliminated propoxyphene and its metabolites principally via the bile, while the rabbit more closely resembled man in excreting the metabolic products into urine. Metabolites in rat and rabbit existed as conjugates, whereas in dog and man the metabolites were excreted as a mixture of the free and unconjugated forms. The primary route of metabolism in all species studied was N-demethylation. However, the rat and rabbit extensively hydroxylated propoxyphene and its metabolites prior to elimination. Metabolites arising from ester hydrolysis were found in rat and man. N-acetylated products were identified in all four species. A metabolite formed from cyclization and dehydration of dinorpropoxyphene was isolated in urine and was further identified as a circulating metabolite in dog plasma.     

ACE-inhibition prevents postischemic coronary leukocyte adhesion and leukocyte-dependent reperfusion injury

OBJECTIVE: Polymorphonuclear leukocytes (PMN), retained in the microvascular bed, can contribute to postischemic myocardial reperfusion injury. Since a beneficial effect of ACE-inhibition on reperfusion injury has been reported, we investigated the impact of cilazaprilat on PMN dependent reperfusion injury in isolated guinea pig hearts. METHODS: Hearts (n = 5 per group) were subjected to 15 min of ischemia. Immediately thereafter, a bolus of PMN was injected into the coronary system. External heart work (EHW) and total cardiac nitric oxide release were measured. For microscopic evaluation, hearts received rhodamine 6G labelled PMN after ischemia, were arrested 5 min later and further perfused with FITC dextran (0.1%). Localization of retained PMN was assessed by fluorescence microscopy. Leukocyte activation was studied by FACS analysis of the adhesion molecule CD11b before and after coronary passage of the PMN. The ACE-inhibitor cilazaprilat (Cila, 2 microM) and the NO-synthase inhibitor nitro-L-arginine (NOLAG, 10 microM) were used to modulate nitric oxide formation of the heart. RESULTS: Postischemic EHW recovered to 67 +/- 5% (controls) and 64 +/- 6% (Cila) of the preischemic value. Addition of PMN severely depressed recovery of EHW (39 +/- 2%) and NO release (39 +/- 6% of the preischemic value). Simultaneously, ischemia led to a substantial increase in postcapillary PMN adhesion (from 21 +/- 5 to 172 +/- 27 PMN/mm2 surface) and CD11b-expression of the recovered PMN (3-fold). Cila attenuated postischemic PMN adhesion (83 +/- 52 PMN/mm2) and activation of PMN, whereas it improved recovery of work performance (64 +/- 4%) and NO release (65 +/- 4%) in the presence of PMN. Conversely, NOLAG increased PMN adhesion (284 +/- 40 PMN/mm2) and myocardial injury. We conclude that ACE-inhibition prevents leukocyte dependent reperfusion injury mainly by inhibition of postcapillary leukocyte adhesion. The effect may be mediated by NO, given the proadhesive effect of NOLAG.     

Comparative pharmacokinetics and metabolism of cephapirin in laboratory animals and humans

Comparative drug disposition studies in mice, rats, dogs, and humans indicate that cephapirin, a new semisynthetic cephalosporin antibiotic that exhibits broad-spectrum antimicrobial activity, is metabolized to desacetylcephapirin in these species. Pharmacokinetic analyses of the concentrations of cephapirin and desacetylcephapirin in plasma and urine reveal that the rate and extent of deacetylation decreases from rodents to dogs to humans. The kinetic analyses also suggest that the kidney performs a role not only in the excretion but also in the metabolism of cephapirin to desacetylcephapirin.     

The role of leukocyte adhesion molecules in acute transplant rejection

The specific adhesion of cells to other cells or to particular tissues or tissue components is a basic function of cell migration and recognition and underlies many biologic processes including embryogenesis, repair, and immunity. Adhesion molecules are involved in and mediate most cell to cell interactions, implement migration of leukocytes to inflammatory or alloantigenic sites, and costimulate well activation and transformation. Because of these functions, the subject of adhesion molecules is gaining broader interest in the field of transplantation, particularly in the conceptualization and development of future treatment strategies. These molecules influence not only the first interaction between host leukocytes and vascular endothelial cells of the graft but also their migration through the grafted tissues. These contacts seem to be based initially on antigen-independent events of adhesion, which then progress to the antigen-dependent events of antigen recognition and host cell activation. This review evaluates current studies concerning the role of adhesion molecules in the context of the multifaceted processes of allograft rejection.     

Ventral dermatitis and vasculitis in a calf with bovine leukocyte adhesion deficiency

Dermatitis and vasculitis of the skin covering the sternum of a calf with bovine leukocyte adhesion deficiency was observed. The calf had been conceived through artificial insemination, delivered by cesarean section, and placed in a gnotobiotic isolator. Dermatitis was noticed at 54 days of age and was not responsive to antibiotic or ivermectin treatment. Proteus sp, Enterobacter sp, and Candida tropicalis were isolated from skin specimens. The lesion was characterized by lymphoplasmacytic and histiocytic inflammation with vasculitis and thrombosis.     

Histamine sustains fMLP-stimulated leukocyte adhesion in rat mesenteric venules in vivo

Hereditary non-syndromic profound deafness affects about 1 in 2000 children prior to language acquisition. In 80% of the cases, the mode of transmission is autosomal recessive. The number of genes involved in these recessive forms of isolated deafness (DFNB genes) has been estimated to between 30 and 100. So far, ten DFNB genes have been mapped to human chromosomes, one of which has been isolated. By linkage analysis of a single family whose members were affected with profound deafness, some of them presenting with vestibular dysfunction, DFNB2 has been mapped to chromosome 11q13 (ref. 3). The gene responsible for a form of Usher syndrome type I, USH1B, has been assigned to the same chromosomal region. Usher syndrome associates profound congenital deafness and vestibular dysfunction with retinitis pigmentosa. In the homologous murine region are located the shaker-1 mutations responsible for deafness and vestibular dysfunction. It has been demonstrated that the murine shaker-1 and human USH1B phenotypes result from mutations in the gene encoding myosin-VIIA. Based on mapping data as well as on the similarities between the phenotypes of DFNB2-affected patients and shaker-1 mouse mutants, we have proposed that a defective myosin-VIIA may also be responsible for DFNB2 (ref. 1). Sequence analysis of each of the coding exons of the myosin-VIIA gene (MYO7A) was thus undertaken in the DFNB2-affected family. In the last nucleotide of exon 15, a G to A transition was detected, a type of mutation that is known to decrease the efficiency of splicing. Accordingly, this result shows that different mutations in MYO7A result in either an isolated or a syndromic form of deafness.     

The leukocyte cell adhesion cascade and its role in myocardial ischemia-reperfusion injury

Cell-cell and cell-matrix interactions are known to be mediated by specific cell adhesion receptors expressed on the cell surface. The characterization of these cell adhesion molecules has allowed researchers to examine their roles in a variety of physiologic and pathophysiologic conditions. Numerous studies have demonstrated that myocardial ischemia-reperfusion injury is an acute inflammatory process in which leukocytes are intimately involved. In this review, we summarize the current data on the leukocyte cell adhesion cascade, focus upon studies which have demonstrated specific cell adhesion molecule interactions which mediate the leukocyte involvement in myocardial ischemia-reperfusion injury and suggest future avenues of exploration and possible clinical implications of the studies reviewed.     

Brugia timori: experimental infection in some laboratory animals

Estimations of the residual glomerular filtration rate (GFR) were made from renography and GFR measurements before unilateral nephrectomy in 28 patients aged 42-77 years. The GFR was measured one week and three months after the operation and comparisons were made between the function of the remaining kidney and the preoperative estimate. In 23 patients where the removed kidney had some function, the mean GFR increased by 32% and 22% after one week and three months, respectively. In 5 patients where the removed kidney had no function, no compensatory hypertrophy occurred.     

Particle inhalability curves for humans and small laboratory animals

Several inhalability curves for nose breathing in humans have been developed. No studies have been designed specifically to develop inhalability functions for animals, although it has been shown that pulmonary deposition of large particles (> 4-5 microns) via inhalation is minimal in laboratory animals [Raabe et al., Inhaled Particles VI, pp. 53-63. Pergamon Press, Oxford (1988)]. The logistic function was fitted to these animal deposition data of Raabe et al. (1988) to estimate an inhalability curve for laboratory animals. The logistic function was also fitted to the human data of Breysse and Swift [Aerosol Sci. Technol. 13, 459-464 (1990)] for comparison. The results suggest that ambient concentration is a good predictor (inhalability > 95%) of inhaled concentration for humans for particles < 11 microns dae. In small laboratory animals, however, the inhalable portion of the ambient concentration is predicted to be 95% for 0.7 microns dae particles but declines to 45% for 10 microns dae particles. It is, therefore, important to consider the effects of inhalability when estimating dose delivered to the target tissue in animals. In comparing delivered doses between animals and humans, adjusting for inhalability may change not only the magnitude of the difference but also which species is predicted to receive a greater delivered dose.     

Neuropathological findings in eight children with cerebro-oculo-facio-skeletal (COFS) syndrome

Cerebro-oculo-facial-skeletal (COFS) syndrome is a rare autosomal recessive disorder with microcephaly, severe mental retardation, and death in childhood. The pathogenesis is unknown. Neuropathological features of 8 children with COFS syndrome are presented. Seven of the children, ranging in age from 36 weeks gestation to 5 years 8 months, are of North American aboriginal background from Manitoba, Canada. The eight child is a 3-year-old Caucasian male. In all children there was severe microencephaly and mild ventriculomegaly. Cerebral myelination appeared to be delayed in one infantile case. Swollen ubiquitinated granular cells appeared in the white matter shortly after birth. Older children displayed cortical neuron loss, patchy or diffuse absence of myelin and gliosis in the white matter, and pericapillary and parenchymal mineralization in the globus pallidus and to a lesser extent the putamen and cerebral cortex. The cerebellum of older children exhibited severe degenerative changes involving the internal granular layer and Purkinje cell layer. The neuropathological changes, previously not well documented, suggest that COFS syndrome is associated with a degenerative process that begins in utero and affects many brain cell types. Similarities to Cockayne syndrome are discussed.     

Stable nonaqueous pentobarbital sodium solutions for use in laboratory animals

The degradation kinetics of pentobarbital sodium in propylene glycol-based solutions were studied along with the in vivo effects in laboratory animals. The degradation rate constant was directly proportional to the water concentration in propylene glycol-water solvent systems. An activation energy of 23.4 kcal/mole was obtained in propylene glycol-water (1:1). Pentobarbital sodium solutions in anhydrous propylene glycol and 9:1 mixtures of propylene glycol with ethanol, glycerin, or dimethylacetamide gave relatively slow degradation rates at 100 degrees with all projected 25 degrees t 99% values greater than 4.5 years. Intravenous administration of pentobarbital sodium in various anhydrous propylene glycol-based vehicles to rats produced no hemolysis of gross organ damage that would interfere with pathological evaluations. Results of an intraperitoneal sleeptime study indicated that pentobarbital sodium produced consistent hypnotic effect when administered as an aqueous solution or in anhydrous propylene glycol-based vehicles.     

Use of laboratory animals in the teaching of emergency procedures

The Division of Emergency Medicine, University of Chicago Hospitals and Clinics uses animal laboratory sessions to train emergency medicine residents in manipulative skills. Certain animals realistically represent the human for these purposes and are delineated for various procedures. On the other hand, animal tissue characteristics and anatomical landmarks generally differ from those of humans. How procedures such as cricothyreotomy; tracheostomy, tube thoracostomy, thoractomy, cardiac repair, aortic cross clamping, venous cutdown, peritoneal lavage, abdominal stab wound exploration and laparotomy can be performed and must be modified is discussed. A rational procedural sequence is required to maintain the animal's vitality through the end of the session.     

Working with laboratory animals: general principles and practical considerations

Laboratory animals play an indispensable role in research discovery and technological advances, and they will continue to yield basic, exciting, and prodigious information that can enrich the future of people and other animals. For both ethical and scientific reasons, all-individuals whose work requires the use of laboratory animals must take the time to conduct a thorough review of the literature to determine what animal models are available and which are the most relevant, and they must learn and understand the uniqueness of the selected species, breed, and strain. Scientists have the privilege, but not the right, to use animals as experimental subjects. This privilege must not be abused. Therefore, it is imperative that before working with any laboratory animal, you know your "subject."     

Biotransformation of linogliride, a hypoglycemic agent in laboratory animals and humans

Following oral administration of linogliride, a hypoglycemic agent, to rat (50 mg kg-1), dog (30 mg kg-1), and man (100 mg per subject), plasma, urine, and fecal extract sample pools were obtained. Nine metabolites plus unchanged linogliride were isolated and identified. The number of metabolites identified were: rat (5), dog (9), and man (1). In each species, more than 78% of the administered dose was recovered in the urine pools. Identified metabolites were estimated to account for > 82% of the total amounts of drug-related sample in urine pools and > 50% in plasma and fecal extract pools. Formation of linogliride metabolites in the three species can be described by four proposed pathways: pyrrolidine hydroxylation, aromatic hydroxylation, morpholine hydroxylation, and imino-bond cleavage. Comparison of the proposed metabolic pathways among species reveals a similarity between rat and dog. In these two species, pyrrolidine hydroxylation was quantitatively the most important pathway, with 5-hydroxylinogliride and dominant hypoglycemic active metabolite in all sample pools. Further oxidation of 5-hydroxylinogliride resulted in the formation of five minor metabolites. The other three pathways appeared to be quantitatively unimportant. Metabolism of linogliride in man occurred to a very limited extent. More than 90% of the total linogliride-related material in plasma was the unchanged drug. Greater than 76% of the administered dose was excreted unchanged in the urine. Only 5-hydroxylinogliride was identified in minor amounts in human samples.     

Metabolic fate of the hypoglycemic agent pirogliride in laboratory animals and humans

Metabolism of the hypoglycemic agent, pirogliride, was investigated in the rat, dog monkey and human. Unchanged pirogliride plus six metabolites were isolated and identified using solvent extraction, HPLC and CI and EI-MS from urine and fecal samples. Pirogliride was metabolized in man to a small extent by oxidation of the 4-position of the phenyl ring. The monkey metabolized pirogliride mainly by oxidation of the pyrrolidine rings, while oxidation of the phenyl ring was the minor pathway. In contrast to the monkey, the rat metabolized pirogliride primarily by oxidation of the phenyl ring. The dog showed a balance of oxidation between the phenyl and pyrrolidine rings.     

Case presentation: bovine leukocyte adhesion deficiency (BLAD) in Switzerland

Bovine Leukocyte Adhesion Deficiency (BLAD) Syndrome is a lethal congenital immunodeficiency caused by the strong reduction in the expression of leukocyte integrins (beta 2 integrins) on the surface of leukocytes. Therefore, neutrophils from BLAD animals lack the capacity to adhere to the endothelium, a necessary step in their emigration into foci of infection. Due to the virtual absence of neutrophil-mediated host defense, animals suffer from recurrent infection of the respiratory and gastrointestinal tracts and finally succumb to infections. A 14 days old Holstein-Friesian calf showing omphalophlebitis and leukocytosis, was referred to our clinic. It was found to suffer from several febrile episodes of infection. The tentative diagnosis BLAD could be confirmed for the first time in Switzerland by flow cytometry, pedigree analysis and by restriction fragment length polymorphism.     

Immobilized heparin inhibits the increase in leukocyte surface expression of adhesion molecules

In our experience, it is easier to identify gas bubbles in ultrasonic images than in aural Doppler signals. To verify this, we asked 27 observers with no previous training to estimate the quantity of gas bubbles in video tapes containing sequences of ultrasound images recorded during decompression experiments. The amount of bubbles was graded according to a non-linear grading system with six levels. The results obtained were compared to evaluations performed on-site by a trained observer. Approximately 70% of the evaluations performed by the untrained observers agreed completely with the on-site gradings, and more than 95% agreed within 1 grade unit. The strength of agreement can be described by use of the weighted kappa statistic, and we have compared the agreement in our study with agreement obtained in a previous study using Doppler signals for bubble detection. We find that in grading bubble signals in images, untrained observers perform equally as well as trained observers grading bubbles in Doppler signals. We conclude that ultrasonic imaging offers a useful and cost-effective alternative to Doppler systems for detection and quantification of intravascular gas bubbles.