Neuronal GM1 gangliosidosis in a Siamese cat with beta-galactosidase deficiency.

A juvenile Siamese cat with severe, progressive motor disability was shown to have extensive neuronal degeneration caused by accumulation of GM(1) ganglioside. Tissues from brain and kidney were markedly deficient in beta-galactosidase activity. The disease in this cat is thought to be inherited as an autosomal recessive trait, and is strikingly similar to juvenile GM(1) gangliosidosis of children.

Mycoplasma pulmonis and lymphoma in bioassays in rats.

Lymphomas were reported to be induced in rats in bioassays of aspartame, methyl-tertiary-butyl ether (MTBE), and other chemicals conducted by a nonprofit cancer research organization. European regulatory authorities concluded that lymphomas in the aspartame study were caused by Mycoplasma pulmonis and suggested that this also was the case for the MTBE bioassay. To assess the role of M. pulmonis in these bioassays, we reviewed the tumor data for the aspartame and MTBE bioassays and, additionally, the organization's bioassay of methanol. For all 3 studies, the most frequently reported hematopoietic neoplasm was lympho-immunoblastic lymphoma, the most frequently affected organ was the lung, and, in almost half of the rats with this diagnosis, the lung was the only affected organ. Lesions diagnosed as lymphoma in published illustrations had pleomorphic cellular morphology and appeared to contain neutrophils. Information from these reports and other sources indicated that lesions typical of M. pulmonis disease were prevalent among the aspartame and MTBE study rats and that the rats were not specific-pathogen-free. Because the lymphoma type, cellular morphology, and organ distribution reported in these studies are atypical of lymphoma in rats, because lymphocyte and plasma cell accumulation in the lung is characteristic of M. pulmonis disease, and because M. pulmonis disease can be exacerbated by experimental manipulations, including chemical treatment, we suggest that a plausible alternative explanation for the reported results of these bioassays is that the studies were confounded by M. pulmonis disease and that lesions of the disease were interpreted as lymphoma.

Mycoplasma pulmonis infections cause long-lasting potentiation of neurogenic inflammation in the respiratory tract of the rat.

These experiments were done to learn whether Mycoplasma pulmonis infections of the respiratory tract of rats can potentiate "neurogenic inflammation" and whether this potentiation is amplified by factors that exacerbate the infections. Pathogen-free F344 rats were inoculated intranasally with M. pulmonis or with sterile culture medium and then lived for 4 wk in an ammonia-free atmosphere or in air containing ammonia (100 parts per million). Neurogenic inflammation was evoked by an intravenous injection of capsaicin, and 5 min later the magnitude of the response was quantified by measuring the amount of extravasation of two tracers, Monastral blue pigment and Evans blue dye. We found that vascular permeability in the tracheas of all rats was normal in the absence of capsaicin. However, a 75-micrograms/kg dose of capsaicin, which caused almost no extravasation of Evans blue in the tracheas of pathogen-free controls (17 +/- 3 ng/mg; mean +/- SE), produced extensive extravasation in the infected rats (135 +/- 18 ng/mg; P less than 0.001). Similarly, this dose of capsaicin produced 30 times as much Monastral blue extravasation in the infected rats (area density = 47 +/- 8% of surface area) as it did in the pathogen-free rats (1.6 +/- 0.5%; P less than 0.001), a difference that resulted from increases in the number of Monastral blue-labeled postcapillary venules and in the amount of labeling per venule. Exposure of the infected rats to ammonia exacerbated the infections, further increased the number of Monastral blue-labeled vessels and the amount of labeling per vessel, and made the rats so sensitive to capsaicin that a normally tolerable dose of 150 micrograms/kg i.v. caused fatal apnea. Ammonia did not have these effects in pathogen-free rats. We conclude that M. pulmonis infections of the airway mucosa cause a potent, long-lasting potentiation of neurogenic inflammation, which results in part from an increase in the number and responsiveness of mediator-sensitive postcapillary venules. These changes can be amplified by environmental factors such as ammonia which exacerbate the infections.

Peritoneal macrophages of pathogen-free rats but not of conventional rats secrete elastolytic activity.

Elicited peritoneal macrophages from Sprague-Dawley rats conventionally bred and housed failed, as we have reported, to produce detectable elastolytic activity in culture. They did produce lysozyme and plasminogen activator. We now show that in contrast to these cells, macrophages from pathogen-free, barrier-sustained rats produced readily demonstrable elastolytic activity. Rats raised pathogen-free and subsequently housed conventionally for 2-4 wk appeared to lose the capacity to afford macrophages producing elastase. At the same time they acquired infections with several rat pathogens including Spironucleus muris, Kilham rat virus, sialodacryoadinitis virus, and mycoplasma pulmonis. The acquisition by the rats of one or more of these infections, conditions conducive to infection, or both factors may have suppressed their capacity to yield elastolytic activity.

Quantitative analysis of Helicobacter pylori infection in a mouse model.

Progress in elucidating the pathogenesis of Helicobacter pylori gastric infection and in developing an H. pylori vaccine will be aided by an animal model in which H. pylori can be reliably detected. To validate the use of the mouse model of H. pylori infection, we determined the susceptibility of three inbred strains of mice (C57BL/6J, C57BL/10J and BALB/c) to two VacA+/CagA+ isolates of H. pylori (SPM326 and M1.16) and determined the effectiveness of microbiological, histological and molecular assays for H. pylori detection. For the detection of H. pylori in inoculated mice, reverse transcriptase-polymerase chain reaction was the most sensitive assay (82%), histological evaluation the next most sensitive (66%) and microbiological evaluation the least sensitive (38%); the assays were equally specific (100%). Of the two H. pylori isolates, M1.16 showed the highest rate of colonization, but SPM326 displayed the highest rate of persistent infection. Among the three mouse strains, C57BL/6J mice showed the highest level of both susceptibility to colonization and persistent infection. Anti-H. pylori antibody responses were induced in all inoculated mice and persisted for up to 8 weeks after H. pylori clearance. These results indicate that inbred mice experimentally infected with H. pylori is a reliable model for human infection, but host susceptibility to colonization and persistence of infection are dependent on the H. pylori isolate and the mouse strain.

Autosomal dominant erythromelalgia.

We present a kindred of 29 persons affected with erythromelalgia (erythermalgia) in 5 generations. This paper updates the family reported by Burbank et al. [1966]. Patients have symptoms of intermittent intense burning limb pain related to increased skin temperature. No successful treatment has been identified, and the pathogenetic mechanism has not been established. Most affected individuals are female.

Factors affecting clinical outcome following endoscopic perforator vein ablation.

BACKGROUND: Despite good outcomes reported with minimally invasive, subfascial endoscopic perforator surgery (SEPS), some patients demonstrate poor healing or recurrence of venous ulcers. The goal of this study was to identify factors that lead to failure of SEPS. METHODS: Forty-eight consecutive patients who had undergone 57 SEPS procedures were analyzed. Mean follow-up was 17 +/- 2 months (range 2 weeks to 52 months). RESULTS: All active ulcers (n = 22) at the time of surgery healed in an average of 99 +/- 37 days (range 11 to 670). Eight limbs had poor healing of their ulcer (>40 days); five (9%) new/recurrent ulcers developed postoperatively. Deep venous obstruction was associated with delayed ulcer healing (316 +/- 171 versus 51 +/- 14 days, P < 0.01) and ulcer recurrence (P < 0.0001). Poor ulcer healing and recurrence were not associated with lipodermatosclerosis, edema, ulcer duration >3 months, or previous recurrences. Ulcer size >2 cm (P < 0.05) and combined ilio-femoral and popliteal/tibial reflux were associated with poor ulcer healing (P < 0.05). CONCLUSIONS: SEPS could not prevent recurrent or new ulceration in 9% of limbs. Venous outflow obstruction was associated with ulcer recurrence and prolonged ulcer healing. Multilevel deep venous reflux and ulcer size >2 cm were also associated with delayed healing.

Ankylosis of hock joints in group caged male B6C3F1 mice.

Enlarged hock joints were observed during 1983 in B6C3F1 mice of chronic toxicity and carcinogenicity studies sponsored by the National Toxicology Program (NTP). Subsequently, approximately 9,500 B6C3F1 mice on 32 NTP chemical toxicity and carcinogenicity studies were evaluated for this condition by clinical examination. Group caged male B6C3F1 mice had thickening and reduced mobility of the hock joints at prevalences of 1.2% up to 6 months of age; 23% at 6 to 12 months of age; and 62% at 13 to 26 months of age. Group caged female B6C3F1 mice had a prevalence of 2% or less. Histologically, affected mice had periarticular exostoses on the bones of the hock joints, with formation of bony bridges around joints and deposition of new bone in joint spaces, resulting in partial or complete ankylosis. Individually caged male and female B6C3F1 mice were not affected. The cause of the ankylosis was not determined, but its occurrence in the NTP studies has been reduced by individual caging.

Experimental Mycoplasma pulmonis infection in pathogen-free mice. Models for studying mycoplasmosis of the respiratory tract.

Mice of a Swiss substrain, reared under rigid pathogen-free (PF) conditions, were inoculated intranasally with broth cultures of Mycoplasma pulmonis ranging in dose from 10(1) to 9 x 10(9) colony forming units (CFU). A highly reproducible disease resulted with an LD(50) of 1.3 x 10(8) CFU and a PD(50) (dose producing pneumonia in 50% of mice) of 3.4 x 10(5) CFU. The inoculating dose of M pulmonis was found to be the critical determinant of the severity, duration and pathologic character of the respiratory disease produced. PF mice given 10(4) CFU or less developed a transient illness characterized by low frequencies of rhinitis, otitis media, laryngotracheitis and focal pneumonia. This was proposed as a low dose model. Doses of 10(5) to 10(9) CFU resulted in high frequencies of rhinitis, otitis media, laryngotracheitis and pneumonia. Within the first 10 days the pneumonia often was fatal, being characterized by an outpouring of neutrophils and edema fluid into alveolar spaces, pulmonary congestion and hemorrhage and, occasionally, pleuritis. This high dose-acute disease model was shown to be the result of seeding alveoli with large numbers of organisms at the time of intranasal inoculation. In animals surviving doses of 10(5) to 10(9) CFU beyond approximately 10 days postinoculation, the larger concentration of organisms was present in bronchi and bronchioles, giving rise to a third model, the high dose-chronic disease model. The predominant lesions were chronic suppurative bronchitis and bronchiolitis, marked peribronchial lymphoid cuffing, variable numbers of neutrophils and macrophages in alveoli, and complications such as bronchiectasis and pulmonary abscesses. Identical lesions were observed in axenic mice infected with M pulmonis. The infection in PF mice is considered a highly useful experimental system, both for comparative study of respiratory mycoplasmosis and for investigations directed toward understanding and eliminating the natural disease this agent causes in conventional mice and rats.

Exacerbation of murine respiratory mycoplasmosis by sialodacryoadenitis virus infection in gnotobiotic F344 rats.

To test the hypothesis that sialodacryoadenitis virus infection could exacerbate respiratory mycoplasmosis in rats, four groups of 40 7- to 9-week-old gnotobiotic F344/N rats were given two intranasal inoculations 7 days apart: Mycoplasma pulmonis, then sialodacryoadenitis virus; M. pulmonis followed by sterile culture medium; medium initially, then virus; or two doses of medium. Immediately and 3, 5, 10, and 20 days after the second inoculation, the nasal passages, middle ears, larynges, tracheas, lungs, and salivary and lacrimal glands of four rats from each group were prepared for histologic examination, and the respiratory organs from four other rats were collected for quantitative culture of M. pulmonis and sialodacryoadenitis virus. To test statistically the effect of virus infection on mycoplasmosis lesions, we determined indices of the severity of respiratory tract lesions by subjective scoring. In rats given both organisms, indices of nasal and tracheal lesions were significantly (P less than 0.05) greater at 3 days and after than in rats given M. pulmonis alone, and middle ear, laryngeal, and lung lesion indices were significantly greater at 5 days and after. Rats given both mycoplasma and virus had significantly more mycoplasmal colony-forming units in the nasal passages at 3 days and after, and in the larynges, tracheas, and lungs at 10 and 20 days, than rats given only mycoplasma. These results show that sialodacryoadenitis virus infection can exacerbate respiratory mycoplasmosis in rats under experimental conditions; therefore, the virus probably also contributes to expression of naturally occurring mycoplasmosis.

Animal models of diabetes and obesity, including the PBB/Ld mouse.

Diabetes mellitus occurs in many animals species. However, only a few have been utilized in systematic studies designed to answer unsolved problems associated with the disorder in man such as molecular basis, pathogenesis of the vascular and neural lesions, and the roles of diet, exercise and obesity. Among the animal models available, rodents have been studied most thoroughly for a number of reasons: a) short generation time (sexually mature at about 3 mo of age, gestation time 21 days) and life-span is approximately 3 yr; b) hyperglycemia and/or obesity is known to be inherited in several species; c) environmental factors can be controlled easily in the laboratory because of small size; and d) economic considerations. The better-known rodent diabetes/obesity syndromes may be categorized as follows: 1) hyperglycemic with ketoacidosis, nonobese (Chinese hamster, South African hamster); 2) hyperglycemic with insulin hypersecretion, moderate obesity and may develop ketoacidosis (diabetic mouse (db/db), spiny mouse, sand rat); and 3) less pronounced hyperglycemia with hyperinsulinemia, insulin "resistance" and marked obesity (obese (ob/ob), yellow (Ay) and New Zealand obese (NZO) mice, and the Zucker "fatty" rat). The PBB/Ld mouse, described here in detail for the first time, is a new strain of mouse that also fits into the latter category. Members of this strain following maturity develop an obesity that is characterized by increasing cellularity of adipose tissue, increased serum immunoreactive insulin, reduced glucose tolerance, fatty liver, and hyperlipidemia. Therefore, this strain of mouse represents another model for study of adult onset obesity.

Cyclophosphamide decreases nitrotyrosine formation and inhibits nitric oxide production by alveolar macrophages in mycoplasmosis.

We previously reported that congenic C57BL/6 inducible nitric oxide synthase(-/-) (iNOS(-/-)) mice infected with Mycoplasma pulmonis developed higher bacterial numbers and lung lesion scores than C57BL/6 iNOS(+/+) controls but had similar lung nitrotyrosine levels. The present studies investigated the role of inflammatory cells in nitrotyrosine formation during mycoplasmal infection. iNOS(+/+) and iNOS(-/-) mice were injected with cyclophosphamide (CYP) and inoculated with 10(7) CFU of M. pulmonis. CYP pretreatment of M. pulmonis-infected iNOS(+/+) and iNOS(-/-) mice reduced polymorphonuclear cells (PMNs) within bronchoalveolar lavages (BALs) by 88 and 72%, respectively, and whole-lung myeloperoxidase levels by 80 and 78%, respectively, at 72 h postinfection but did not alter the number of alveolar macrophages (AMs) in BALs. CYP treatment also significantly decreased nitrate and nitrite (NOx) levels in BALs and plasma of infected iNOS(+/+) mice, whereas neither CYP nor mycoplasmal infection altered NOx in iNOS(-/-) mice. CYP reduced lung nitrotyrosine levels in both iNOS(+/+) and iNOS(-/-) mice to uninfected-control levels as shown by immunohistochemical staining and enzyme-linked immunosorbent assay and inhibited mycoplasmal killing by iNOS(+/+) mice in vivo. CYP inhibited the production of gamma interferon-inducible NOx by iNOS(+/+) AMs in vitro but did not alter the number of iNOS-positive AMs, as detected by immunocytochemistry. In addition, AMs from CYP-treated iNOS(+/+) mice had significantly decreased ability to kill mycoplasmas in vitro. These results demonstrate that reactive species generated by inflammatory cells as well as PMN myeloperoxidase are important contributors to nitrotyrosine formation during mycoplasmal infection and that treatment with CYP decreases NO* production by AMs and inhibits mycoplasmal killing.

Lack of amiloride-sensitive transport across alveolar and respiratory epithelium of iNOS(-/-) mice in vivo.

The extent to which endogenously generated nitric oxide alters Na(+) transport across the mammalian alveolar epithelium in vivo has not been documented. Herein we measured alveolar fluid clearance and nasal potential differences in mice lacking the inducible form of nitric oxide synthase [iNOS; iNOS(-/-)] and their corresponding wild-type controls [iNOS(+/+)]. Alveolar fluid clearance values in iNOS(+/+) and iNOS(-/-) anesthetized mice with normal oxygenation and acid-base balance were ~30% of instilled fluid/30 min. In both groups of mice, fluid absorption was dependent on vectorial Na(+) movement. Amiloride (1.5 mM) decreased alveolar fluid clearance in iNOS(+/+) mice by 61%, whereas forskolin (50 microM) increased alveolar fluid clearance by 55% by stimulating amiloride-insensitive pathways. Neither agent altered alveolar fluid clearance in iNOS(-/-) mice. Hyperoxia upregulated iNOS expression in iNOS(+/+) mice and decreased their amiloride-sensitive component of alveolar fluid clearance but had no effect on the corresponding values in iNOS(-/-) mice. Nasal potential difference measurements were consistent with alveolar fluid clearance in that both groups of mice had similar baseline values, which were amiloride sensitive in the iNOS(+/+) but not in the iNOS(-/-) mice. These data suggest that nitric oxide produced by iNOS under basal conditions plays an important role in regulating amiloride-sensitive Na(+) channels in alveolar and airway epithelia.

Requirements and selection of an animal model.

There are two broad classes of models: those based on analogy (similar structures imply similar functions), and those based on homology (structures derived from the same evolutionary precursor have the same or similar functions). There are four main categories of animal models: 1) induced or experimental models, that attempt to reproduce conditions found in the original species, 2) spontaneous or natural models, that are recognized as being similar to some condition in the original species, 3) negative or nonreactive models, that are the normal counterparts of a disease model, and 4) orphan models, that are animal diseases for which no human or animal counterpart is known. The selection of any model, but particularly animal models, for research should be based on the following considerations: 1) appropriateness as an analog, 2) transferability of information, 3) genetic uniformity of organisms, where applicable, 4) background knowledge of biological properties, 5) cost and availability, 6) generalizability of the results, 7) ease of and adaptability to experimental manipulation, 8) ecological consequences, and 9) ethical implications. The criteria for selection or rejection of particular animal models also include customary practice within a particular discipline, the existence of diseases or conditions that might complicate results, the existing body of knowledge on the problem under consideration, and special features of the animal, such as unique responses or microflora, that may make a particular species useful.

Accumulation of amyloid-beta protein in exocrine glands of transgenic mice overexpressing a carboxyl terminal portion of amyloid protein precursor.

Amyloid-beta protein (Abeta) and its precursor (betaPP) play important roles in the pathogenesis of Alzheimer disease and inclusion-body myositis. In humans, Abeta deposits are found in brain, skeletal muscle, and skin. Therefore, we have investigated possible Abeta deposits in multiple tissues of two transgenic mouse lines overexpressing the signal plus Abeta-bearing 99-amino acid carboxyl terminal sequences of betaPP under the control of a cytomegalovirus enhancer/beta-actin promoter. One of the lines developed Abeta-immunoreactive intracellular deposits consistently in the pancreas and lacrimal gland, and occasionally in gastric, DeSteno's, and lingual glands. Although the Abeta deposits increased during ageing and degenerative changes of the tissues were observed, little or no extracellular Abeta deposits were observed up to the age of 25 months. These lines of transgenic mice are useful for studying the molecular mechanisms of development and clearance of intracellular Abeta deposits.