Current information about Helicobacter infections in humans and various domestic, wild, and research animal species that have been used or have the potential to be used as animal models of human disease is presented. The Helicobacter genus now includes at least 26 formally named species, with additional novel species in the process of being characterized. The natural history, host range with zoonosis potential, pathology, and diagnostic techniques are presented, along with examples of how Helicobacter infection has interfered with unrelated in vivo research. Current recommendations for deriving and managing helicobacter-free animal colonies for research are provided.

Purpose. To determine the safety and effectiveness of laparoscopy for repeated intra-abdominal biopsy of liver and omental adipose tissue (AT) in obese rhesus monkeys (Macaca mulatta). Methods. Nine obese rhesus monkeys were studied by use of 18 laparoscopic procedures (two procedures each, approx. six weeks apart). Time-sensitive liver and omental AT specimens were obtained from monkeys under general anesthesia, using a three-port approach with a roticulating endoscopic stapler/divider and a monopolar electrosurgery for hemostasis. Results. All subjects tolerated the initial and repeat laparoscopic procedures well. Liver specimens weighed a mean ± SEM of 3.8 ± 0.5 g, and omental AT specimens weighed 16.6 ± 0.8 g. Compared with previous studies of conventional laparotomy with liver wedge resection, the monkeys experienced faster postoperative recovery via laparoscopy, with rapid return to normal food intake and activity. Minimal to no adhesions were observed by use of the repeat procedure in all monkeys, with no major complications. Conclusions. Laparoscopy in obese rhesus monkey (ranging from young to older-aged), with repeated intra-abdominal liver and omental AT biopsy, was an excellent minimally invasive surgical method. In contrast to laparotomy with wedge resection, this approach greatly decreases operative time and stress, provides generous tissue specimens in a time-efficient manner, and facilitates rapid and full recovery of the nonhuman primate.

Purpose: To identify the metabolites produced from an isoflavonoid, daidzein, by colonic bacteria of rhesus monkeys. Methods: The metabolism of daidzein by the fecal bacteria of nine monkeys was investigated. Daidzein was incubated anaerobically with fecal bacteria, and the metabolites were analyzed by use of liquid chromatography and mass spectrometry. Results: The fecal bacteria of all of the monkeys metabolized daidzein to various extents. Dihydrodaidzein was found in cultures of fecal bacteria from two monkeys; dihydrodaidzein and equol were found in cultures from four monkeys; dihydrodaidzein, equol, and an unknown metabolite (MW = 244) were found in cultures from one monkey; and dihydrodaidzein and the unknown metabolite were found in cultures from two monkeys. Conclusions: Similar to that in humans, variation was evident in the metabolism of isoflavonoids by fecal bacteria from rhesus monkeys. Some metabolites produced by fecal bacteria from monkeys were the same as those produced by fecal bacteria from humans.

Husbandry and health of the African clawed frog, Xenopus laevis, greatly influences the quality of oocytes produced. One factor affecting oocyte quality is the water conditions in which females are maintained. Dechlorination and adequate salt concentration are known to affect oocytes, but water hardness has not been considered an important factor in Xenopus husbandry by the research community. We found that, when females were kept in soft water or water with marine salts alone, even when it was cooled to 17 to 18°C, the quality of oocytes decreased; only 20 to 25% of resulting embryos developed to tailbud stages. Survival and normal development of embryos increased significantly within one month of addition to the laboratory housing water of salts that mimic conditions in African Rift Valley lakes. These salts greatly increased water hardness; development of embryos to tailbud stages remained high (50 to 70% on average) for more than a year after their addition to the water housing females. Water from South African ponds where X. laevis are collected, and from wells used by the major suppliers of X. laevis, also was moderately to very hard. Our results suggest that X. laevis is naturally adapted to hard water, and indicate that increasing general hardness during laboratory housing is more important for oocyte quality and embryo development than is increasing carbonate hardness (alkalinity) in the water used to house females.

The C57BL/6J mouse strain is widely used as a common genomic background for many gene-modified murine models. However, few data on its clinical biochemistry are available. Therefore, we conducted a study to provide new protocols for serum biochemical screening and developed the reference range for a set of 13 analytes that pertain to lipoprotein metabolism, electrolyte balance, and data reflecting function of the heart, liver, kidneys, and pancreas. Male and female mice were studied, and blood samples were obtained at six and 20 weeks of age. Of 13 parameters studied, 12 were affected by age and sex. Briefly, male mice had higher triglycerides, cholesterol, high-density lipoprotein cholesterol, glucose, and amylase values. With age, mice of both sexes developed higher triglycerides and glucose concentrations, as well as aspartate and alanine transaminase activities. A significant difference between mice and humans was noted for amylase activity, which is extremely high in this healthy mouse strain. Therefore, we suggest that caution should be taken when data are interpreted to indicate gastrointestinal disease in murine models. The reference values for murine clinical biochemical analytes obtained during the study reported here should be useful for characterizing the biochemical phenotype of experimental mice.

The purpose of the study reported here was to define strain differences in spermatogenesis in cryptorchid testes in mice. Mice of strains A/J, BALB/c, CBA/N, C3H/He, C57BL/6 (B6), ddY and ICR were found to be sensitive to heat stress attributable to experimentally induced cryptorchidism. In contrast, mice of strains AKR/N (AKR), MRL/MpJ-+/+ (M+) and MRL/MpJ-lpr/lpr (lpr) were resistant to heat stress. Relative increases of apoptotic cells were detected in the sensitive group, but not in the resistant group. A decrease of proliferating cell nuclear antigen-immunoreactive cells after experimentally induced cryptorchidism was observed only in the sensitive group. These results suggested that heat stress-resistant germ cells were present in MRL and AKR strains, possibly originating from the genetic background.

Klebsiella pneumoniae is a common cause of nosocomially acquired pneumonia in immunocompromised patients. Previously, we established a pneumonia model using Klebsiella pneumoniae in B6D2F₁/J mice sublethally irradiated with 7-Gy ⁶⁰Co γ-radiation and inoculated intratracheally. In the study reported here, we investigated survival of mice following 10 days of antimicrobial therapy with ceftriaxone, gentamicin, gatifloxacin, and a ceftriaxone-gentamicin combination given once daily. Survival was significantly prolonged in response to all therapies. However, survival of mice was 95% when treated with the ceftriaxone-gentamicin combination followed by ceftriaxone alone (75%), and gatifloxacin (80%), whereas survival for controls was 0%. In addition, resistance to any of the treatments did not develop during the study. We conclude that an immunocompromised status does not alter the Infectious Disease Society of America's primary recommendation for treating community-acquired K. pneumoniae pneumonia using a third-generation cephalosporin, with or without an aminoglycoside.

Partial sequences from mitochondrial (mt) 12S and 16S rRNA genes were analyzed to characterize diversity among captive rhesus macaques (Macaca mulatta) originating from various geographic regions. Several nested clades, defined by closely related haplotypes, were identified, suggesting considerable genetic subdivision, probably relics from heterogeneous origins, founder effects, and genetic drift, followed by breeding isolation. The rhesus matrilineages from India differed discretely and markedly from Chinese matrilineages; approximately 90% of the genetic heterogeneity among the combined samples of Indian and Chinese rhesus macaques studied here was due to country of origin. In addition, mtDNA sequences from macaques of China were more diverse than those from rhesus macaques of India, an outcome consistent with China's greater subspecies diversity and with nuclear genotype distributions. Otherwise, the distribution of mtDNA variation within rhesus macaques of China, and especially within those of India, exhibited far less structure and did not conform to a simple isolation-by-distance model. As the demand for genetically heterogeneous and well-characterized rhesus macaques for biomedical-based research increases, mtDNA haplotypes can be useful for genetically defining, preserving maximal levels of genetic diversity within, and confirming the geographic origin of captive breeding groups of rhesus macaques.

Experiments involving investigation of the neuroendocrine basis for paternal care in rodents risk activation of aggressive behavior toward pups. To minimize pain and suffering during tests of parental responsiveness requiring retrieval of a displaced pup to its nest, a method of anesthetizing the pup was developed in Djungarian hamsters, Phodopus campbelli. A surgical plane of anesthesia, as measured by criteria, such as respiratory depression, loss of the pedal reflex, and failure to increase respiratory rate or to vocalize in response to handling, was achieved by use of intraperitoneal administration of a combination of ketamine and xylazine. Both parents (tested separately) expressed normal behavior toward anesthetized pups. In random order, a saline-injected or anesthetized pup was displaced from its nest in the home cage. There were no differences in pick-up or retrieval rates between saline and anesthetized pups for either parent. A third test using an unmanipulated pup confirmed that parental behavior was not reduced toward an anesthetized pup. However, if anesthetized pups were tested first among littermates, retrieval by males was less likely. This method will, therefore, underestimate retrieval behavior in males, but not females. Adult male hamsters that had never been parents also expressed expected behavior by attacking the pup in 45% of cases. This method provides an efficient and effective means of protecting pups while allowing adults to express a wide range of parental and infanticidal behaviors. It also has application in behavioral screening of transgenic strains toward unrelated young.

Xenoengraftment of human cells in mice with severe combined immunodeficiency (SCID) has been used as a model system to study the mechanisms of B-cell lymphomagenesis. In the study reported here, we determined that SCID mice can also be used as a model to study angiogenesis in B-cell lymphomas. The C. B-17 scid/scid mice were xenotransplanted with Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines (LCL), and we determined whether CD31, a marker found on endothelial cells, was detected in the human B-cell lymphomas that developed in these mice. Microvessel formation was identified by use of immunohistochemical staining for CD31. To assess possible mechanisms of angiogenic stimulus, we analyzed the expression of interleukin 8 (IL-8), a chemokine documented to promote angiogenesis, in non–small-cell lung cancer and bronchogenic carcinomas. We observed that a panel of LCL and LCL-lymphomas expressed IL-8 mRNA and protein. Neutralization of IL-8, however, did not inhibit lymphomagenesis, suggesting that IL-8 is not essential for angiogenesis in this model. To examine other parameters of angiogenesis, we identified expression of vascular endothelial growth factor in the lymphomas. These data suggest that angiogenesis accompanies EBV-associated B-cell lymphoma development, but IL-8 is not essential for this process. Thus, the SCID mouse model is amenable to testing of anti-angiogenic factors.

Animal diseases that develop spontaneously in a limited subpopulation can provide powerful models of human disease because they provide a means to investigate the interaction of a broad range of biological and environmental etiologic processes. In contrast, with experimentally induced animal models, the etiology of the model is inherently fixed, and can only speak to a limited subset of those involved in the human disease. 'Barbering' (abnormal whisker-and fur-plucking behavior) in mice resembles human trichotillomania (compulsive hair plucking) in that barbering mice pluck focused areas of hair, and engage in post-plucking manipulatory and oral behaviors. We performed a cross-sectional epidemiologic survey of a population of 2,950 laboratory mice to further assess the face validity of barbering as a spontaneous model of trichotillomania. Patterns of hair loss and demographic and etiologic risk factors were recorded for each mouse, and were analyzed by use of logistic regression. Barbering paralleled trichotillomania in terms of phenomenology, demography, and etiology. Thus, similar to trichotillomania, barbers predominately plucked hair from the scalp and around the eyes and the genitals; barbering was female biased, and had its onset during puberty; and etiologic factors included reproductive status and genetic background. Therefore, barbering has excellent face validity as a model of trichotillomania, and may represent a refined and non-invasive model, especially for studies of the complex genetic/environmental etiologies of this disorder.