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J R Leininger

Publications and source records attributed to J R Leininger.

48 records · Page 3Linked to original sources
PubMed1980

The effects of long-term ingestion of asbestos on the colon of F344 rats.

Weanling F344 rats, which were fed a diet containing 10% chrysotile (B), were studied over their life-time to determine the effects of ingested asbestos on the colon. Control groups consisted of rats fed a diet containing a 10% nonnutritive cellulose or a standard laboratory rat diet. The pathological findings in the colons of 501 rats (189 on asbestos diet, 197 on fiber control diet, and 115 on standard control diet), are reported here. Epithelial tumors of the colon (eight adenocarcinomas and one adenoma) were found in nine of the rats on study. Four of the tumors were in asbestos-fed rats, two tumors were found in the non-nutritive cellulose controls, and three tumors were found in the standard laboratory rat diet controls. The probability (based on actuarial analysis) of developing adenoma or adenocarcinomas during the 32 months of the study were 7.4% for the asbestos-fed group, 3.5% for the fiber control diet and 4.0% on the standard control diet. In addition, one malignant mesothelioma of the type induced by intraperitoneally administered asbestos was found in the asbestos-fed group. Non-neoplastic lesions of the colon were also evaluated. The cumulative risk for development of any colon-associated lesion (non-neoplastic plus neoplastic lesions) was greatest for asbestos-fed rats (17.9%), compared to 13.6% for those fed the fiber control diet and 8.2% for those fed the standard control diet. The colon tissue levels of adenosine, 3'-5'-cyclic monophosphate (cAMP) were significantly lower in the animals fed asbestos compared to the control diets. Chrysotile fibers were seen by electronmicroscopy (e.m.) in six of ten ashed colon specimens of rats fed the asbestos diet. Although the differences in numbers of tumors between the animals fed asbestos and the controls were not statistically significant at the 5% level, we felt that the combination of observations including 1) evidence of increased probability of asbestos-fed animals to develop colon lesions in general; 2) evidence of a special type of mesothelioma in rats fed asbestos; 3) evidence for a cell regulator defect (lowered cAMP levels) in colon tissues of animals fed asbestos; and 4) evidence for asbestos fiber penetration of the colonic mucosa (e.m. studies) suggest that ingested asbestos is not inert in the colon.

Adenocarcinoma↗
PubMed1980

Leprosy in a chimpanzee. Postmortem lesions.

A young (5-7 year old) male chimpanzee died 33 months after the first clinical manifestations of a naturally acquired disease that was similar to disseminated leprosy in man. At autopsy there were diffuse or multifocal histiocytic infiltrations of the skin, nasal mucosa, pharynx, lung interstitium, liver, spleen, sclera, testicles, adrenal glands, and peripheral lymph nodes. Major nerves of the forearms had extensive fibrosis. There were large numbers of acid-fast bacilli (AFB), many occurring as globi, in histiocytes in most affected tissues including nerves. The histopathologic features of the disease and the microbiologic and antigenic properties of the AFB in the tissues indicate that Mycobacterium leprae or an organism indistinguishable from it was the causative agent. This and other cases of leprosy in nonhuman primates indicate that studies of the development of nonhuman primate models for leprosy may be worthwhile.

Animals↗
PubMed1979

Regurgitation and choke in rats.

Male and female F344 rats choked on fecal pellets and regurgitant during the course of two long-term experiments. Each study involved feeding standard and high bulk diets containing 10% wood cellulose or 10% chrysotile asbestos fiber. Choke deaths occurred at all stages of the experiments. A total of 36 of 774 (4.6%) rats in the two studies died of choke. Females died of choke more frequently (26/382 or 6.8%) than did males (10/392 or 2.6%). Rats on high bulk diets were affected more frequently (33/571 or 5.8%), especially those on 10% asbestos diet (26/311 or 8.4%, than rats consuming standard diet (3/190 or 1.6%). The reason for the difference between females and males was not determined. Although choke may be related to some characteristics of high nonnutritive bulk feed fed in pellet form, the higher risk for females even on standard diet (3/95 or 3.2%) than for males (0/95) indicated that more than one factor operated in the etiology of these events.

Airway Obstruction↗
PubMed1978

Leprosy in a chimpanzee. Morphology of the skin lesions and characterization of the organism.

Microscopic features of lepromatoid lesions in a chimpanzee inoculated with bovine leukemia virus consisted of diffuse dermal infiltrations of foamy histiocytes, except for a subepidermal "clear zone" devoid of infiltrating cells. Acid-fast organisms were in histiocytes, dermal nerves and a branch of the left radial nerve. The organisms were more intensely acid-fast with the Fite-Faraco than with the Ziehl-Neelsen stain. The organisms did not oxidize 3,4-dihydroxyphenylalanine (dopa) to indole but their acid-fast staining quality was removed by pretreatment with pyridine. Human leprosy patients, inoculated simultaneously with chimpanzee and human lepromin, reacted similarly to both lepromins. Organisms, when inoculated into mouse footpads, multipllied in 6 months to a quantity that was compatible with their identification as Mycobacterium leprae.

Animals↗
PubMed1977

Spontaneous leprosy-like disease in a chimpanzee.

The clinical and laboratory findings of a spontaneous disease, resembling human leprosy, in a chimpanzee are described. The disease was a chronic progressive dermatitis characterized by nodular thickenings of the dermis and involving the ears, eyebrows, nostrils, and lips. A maculopapular rash was also present. Numerous acid-fast organisms were found in nasal swabs and in dermal lesions, including nerves. Attempts to culture acid-fast organisms in artificial media have failed. At this time, the only features of the etiologic agent of this disease that are inconsistent with those of Mycobacterium leprae are failure of the organisms to oxidize 3, 4-dihydroxyphenylalanine and failure to pyridine to remove the acid-fast staining property of the bacilli.

Animals↗
PubMed1977

Acute lung lesions due to zirconium and aluminum compounds in hamsters.

The lung lesions produced by multiple short-term intratracheal instillations of saline solutions of sodium zirconium lactate (NaZL), zirconium-aluminum-glycine hydroxychloride complex (ZAG), and aluminum chlorhydrate (ACH) in hamsters were studied by light and electron microscopy. These solutions produced lesions beginning with exudative pneumonia followed by pneumonitis (interstitial pneumonia) and foreign body granulomas. Electron microscopic microprobe analysis demonstrated the metallic component of the instilled compounds in membrane-bound cytoplasmic inclusions of macrophages. The lesions produced by NaZL and ZAG were similar to those produced by ACH. These lesions were also similar to those in previous reports of aerosol exposure of animals to zirconium or aluminum, or to other unrelated compounds.

Aluminum↗
PubMed1976

Feline glomeruli: morphologic comparisons in normal, autolytic, and diseased kidneys.

Twelve cats were used to study autolytic changes in glomerular morphology and compare these with lesions of naturally occurring feline renal disease. The 12 cats had normal clinical, urinary, and blood features. One kidney (0-hour control) was excised immediately after a given cat was euthanatized, and portions of it were prepared for light and electron microscopy. The opposite kidney (autolytic) remained in situ for selected postmortem intervals, up to 24 hours, at which time it was similarly processed. Renal tissues from 4 additional cats (3 with proteinuria and 1 with diabetes mellitus) were processed and examined for comparison. Zero-hour control kidneys had the following mean quantitations: renal weight was 9.9 g; glomerular diameter, 83 mum; number of cells per glomerulus in 1-mum section was 63; and diameter of cell nuclei was 6.3 mum for mesangial, 6.7 mum for visceral epithelial, and 6.4 mum for endothelial. In comparison with 0-hour control kidneys, autolytic kidneys had increased weight and glomerular diameter, but the diameter of cell nuclei decreased. Basement membrane thickness and glomerular cell numbers did not differ between 0-hour control and autolytic kidneys. Kidneys from 4 diseased cats had increased glomerular diameter and glomerular basement membrane changes characterized by hyalin thickening and dense deposits. These changes are compatible with a lesion diagnosis of membranous glomerulonephritis.

Animals↗