Our objectives were to describe the ultrastructural morphogenesis of pulmonary lesions induced by 3-methylindole in 30- to 45-day-old Holstein calves and to determine whether toxic exposure to 3-methylindole exacerbates pulmonary lesions induced by bovine respiratory syncytial virus. Administration of 3-methylindole (0.25 g/kg) to calves resulted in interstitial edema and ultrastructural swelling of type-I alveolar epithelial cells and nonciliated bronchiolar epithelial cells as early as 4 to 6 hours after intraruminal administration. More severe alveolar edema containing protein was associated with swelling of capillary endothelial cells at 2 days after administration. Proliferation of type-II alveolar epithelial cells was first observed at 2 days after 3-methylindole administration, and marked hyperplasia of type-II epithelial cells and nonciliated bronchiolar epithelial cells was evident by 4 days after administration. Pulmonary cytochrome P-450 monooxygenase concentrations decreased significantly (P < 0.001) by 12 hours after administration and did not increase significantly again by 8 days after administration. Calves were inoculated with bovine respiratory syncytial virus 3 days after administration of 3-methylindole, and pulmonary lesions were assessed 5 days after viral inoculation. Viral replication was demonstrated by fluorescence microscopy for viral antigen or by transmission electron microscopy in ciliated and nonciliated airway epithelial cells. Viral antigen was identified infrequently in alveolar macrophages and in type-II alveolar epithelial cells. 3-Methylindole exposure in calves did not result in more widespread distribution of viral antigen in alveolar tissue of respiratory syncytial virus-inoculated calves or in significant enhancement of viral pneumonia. The results indicated that young calves are susceptible to 3-methylindole-induced pulmonary injury and that nonciliated bronchiolar epithelial cells, type-I alveolar epithelial cells, and pulmonary endothelial cells are most susceptible to injury. The results failed to indicate that 3-methylindole pulmonary toxicosis significantly enhances respiratory disease induced by bovine respiratory syncytial virus.

Pemphigus antigens were localized, by use of immunoelectron microscopy, on canine keratinocytes in vivo on esophageal mucosa and in vitro on established cultured keratinocytes. Convalescent sera from a human being with pemphigus vulgaris and a human being with pemphigus foliaceus reacted with the interdesmosomal cytoplasmic keratinocyte membrane of canine esophagus. Cultured canine keratinocytes expressed the pemphigus vulgaris antigen in a similar pattern, but did not carry the pemphigus foliaceus antigen. The differential presence of cell surface antigens and its relation to various forms of the disease are discussed.

Intranuclear inclusions indicative of adenovirus infection were detected microscopically in formalin-fixed intestinal tissues from preweanling Syrian hamsters. The amphophilic intranuclear inclusion bodies were observed in ileal enterocytes from 16-to 24-day-old hamsters. Electron microscopy revealed large numbers of 72 +/- 3-nm viral particles typical of adenoviridae in enterocytic nuclei. Serum antibodies reacted with mouse adenovirus strains K87 and, to a lesser extent, FL, by indirect fluorescent antibody testing. Clinical disease was not associated with the adenoviral infections. Hamsters from 10 production colonies, including all major commercial Syrian hamster suppliers in the United States, were surveyed and all had serologic or histopathologic evidence of adenovirus infection.

A sublethal dose of ethylene glycol was administered orally to 3 groups of dogs; dogs of a control group were given distilled water instead. Renal cortical biopsy samples were obtained from dogs of experimental and control groups at various times after treatment. Tissue was examined by use of light microscopy and transmission electron microscopy. In dogs of the control group, the light and electron microscopic appearances of tissue were within normal limits at all sample collection hours. In dogs of the experimental groups, renal corpuscular structure remained within normal limits by use of light and electron microscopy throughout the study, though morphologic change was seen in other structures of the cortex. Light microscopic lesions first appeared at 12 hours, and were similar to those reported in the literature. Ultrastructural lesions were first observed in the 5-hour samples, and similar to the light microscopic lesions, were most common in the proximal convoluted tubules (PCT). Initial PCT cellular changes included vacuolization of cells and distention of the parabasal extracellular spaces; PCT cellular lesions seen in later-hour samples included formation of apical buds and cellular rupture. Internalization or sloughing of the PCT brush border was not observed. Distal convoluted tubules (DCT) were frequently dilated and/or packed with cellular debris. A few DCT cells had degenerative or necrotic changes. In PCT and DCT, abnormal cells were frequently flanked by normal or nearly normal cells. During later hours, a few cells with types of changes first observed in early hours continued to be observed, implying ongoing response of cells to the toxin.

Light microscopy, morphometry, and scanning electron microscopy were used to examine the mucosal morphologic features of 7 intestinal specimens (3 from the small intestine; 4 from the large intestine) from each of 8 horses 1 year after sham operation (group 1; n = 3) or extensive large-colon resection (group 2; n = 5). Qualitative light microscopic examination did not reveal differences between groups, but morphometry revealed significantly (P < 0.05) greater intercrypt area and distance in horses with colon resection and this was most pronounced in the cecum and remaining right ventral and dorsal colon. Crypt area and depth were similar for horses with colon resection and sham operation (P > 0.05). Qualitative evaluation of the scanning electron micrographs revealed more prominent crypt orifices in the large intestine of horses with colon resection. The larger intercrypt distance in the colon of horses with resection was not an obvious feature of the qualitative evaluation of the surface with scanning electron microscopy. Small intestinal morphologic features were variable and significant differences were not detected between horses with sham operation and colon resection. Horses adapted to extensive large-colon resection within 1 year by increasing the absorptive (intercrypt) surface area of the remaining large intestine.

Pleuropneumonia is an important disease of swine caused by Actinobacillus pleuropneumoniae. Putative virulence determinants include capsule, lipopolysaccharide, and cytotoxin. We studied the virulence and virulence determinants of 2 strains: CM5 and CM5A of serotype 1. Strain CM5 was isolated from a pig with pleuropneumonia and passaged once in vitro; strain CM5A was a substrain of CM5 passaged 70 times in vitro. Pigs challenge exposed to an aerosol of 1.3 x 10(7) colony-forming units of CM5/ml died within 30 hours; pigs challenge exposed to an aerosol of 1.6 X 10(8) colony-forming units of CM5A/ml survived. The average thickness of the capsular layer was 137 nm in strain CM5 and 53 nm in strain CM5A in bacteria treated with homologous antibody and examined by transmission electron microscopy. Similarly, capsular material binding polycationic ferritin was found in colonies of strain CM5, but not in strain CM5A. The ratio of hexosamine to protein in extracted capsule of CM5 was more than twice that of CM5A. The polyacrylamide gel electrophoretic profile of the lipopolysaccharide, outer membrane proteins, and whole cell proteins did not differ between the 2 strains. Also, the amount of cytotoxin or endotoxin produced by the 2 strains during the logarithmic growth phase was not different. The electrophoretic profile of restriction endonuclease digested DNA was similar, with the exception of bands in the 750- and 620-basepair regions. It was concluded that attenuation of strain CM5A during in vitro passage was a result of reduced capsule production and that encapsulation is an important virulence determinant of A pleuropneumoniae, serotype 1.

Genital tracts from 15 cows with catarrhal and purulent inflammation of the uterus and uterine tubes, cystic hyperplasia of the endometrium, or hydrosalpinx were evaluated by use of scanning electron microscopy to determine epithelial changes associated with these conditions. Uterine epithelium was revealed to be easily damaged, even in the course of mild inflammation, whereas epithelium of the uterine tube was more resistant.

The effect Of bovine mammary secretion during the nonlactating period and of antibiotic preparations on bovine polymorphonuclear neutrophil (PMN) phagocytic function and morphology were evaluated in a series of in vitro multifactorial experiments. Benzathine cloxacillin (CL), benzathine cephapirin (CE), sodium novobiocin (NO), and a combination of dihydrostreptomycin with procaine penicillin G (DP) were prepared in the presence and absence of a peanut oil aluminum monostearate vehicle. The PMN were isolated from bovine blood, and the effect of each antibiotic preparation on PMN function and morphology was evaluated in a buffer, fat, skim, and a combination of fat with skim from bovine mammary secretion during the nonlactating period. The fat and skim were diluted with buffer to approximate their concentration in mammary secretion. Phagocytic functions of PMN were monitored by fluorescent microscopy, which made it possible to estimate both ingestion and intracellular killing of bacteria by PMN. Changes in PMN morphology were monitored by transmission electron microscopy. The ability of PMN to ingest and kill Staphylococcus aureus ATCC 25923 was significantly decreased by fat, skim, CL, CE, NO, and DP. Effects of some antibiotics on ingestion and killing of bacteria by PMN were influenced by the addition of vehicle and by interactions with mammary secretion. Neutrophil morphology was altered by fat, skim, CL, CE, NO, and DP. The detrimental effects of CL, CE, NO, and DP on PMN morphology were influenced (some significantly) by the presence of vehicle and interactions with mammary secretion. There were significant correlations among secretion- and antibiotic-induced changes in PMN ingestion of bacteria, PMN killing of bacteria, and PMN morphology.

The effects of 2 antibiotic preparations administered intramammarily on phagocyte recruitment, function, an morphology were evaluated at the beginning of the nonlactating period. Twelve cows with no clinical or micro biologic evidence of mastitis were assigned to 1 of 2 treatment groups. At the end of lactation, 1 of the antibiotic preparations was infused in a fore- and hind quarter of each cow; the remaining quarters were untreated controls. One group was given benzathine cephapirin; the second group was given sodium novobiocin. Secretion samples were collected from 1 treated and 1 control quarter at 16 hours, and from the remaining 2 quarters at 64 hours after treatment. Total and differential somatic cell counts were determined, and morphology of mammary polymorphonuclear neutrophils (PMN) and macrophages was observed by transmission electron microscopy. In vitro ingestion and killing of Staphylococcus aureus by mammary PMN and macrophages were assessed by fluorescent microscopy, using acridine orange stain. Cells resident in a fixed volume of secretion were incubated with a known concentration of S aureus. Total cell and PMN concentrations were higher in treated than in control quarters. Neutrophils were the predominant cell type in both treated and control quarters over the sampling period. As measured in this study, in vitro ingestion and killing of S aureus by individual PMN from treated quarters was reduced. Antibiotic treatment also increased the proportion of morphologically abnormal phagocytes. There were significant correlations among PMN ingestion, killing, and morphology. However, increased PMN concentrations tended to compensate for the reduced phagocytic function of individual cells. Therefore, efficacy of antibiotic treatment of nonlactating cows may depend, at least in part, on increased PMN concentration, which may tend to compensate for reduced phagocytic function. Compared with PMN, macrophages appeared to have only a minor role in phagocytosis of bacteria.

Plasmid profiles were compared between nonpiliated and piliated forms of Moraxella bovis isolates. The piliated form of M bovis isolate IBH64 contained 1 fewer plasmid than did the nonpiliated form. Piliated and nonpiliated cells of IBH64 contained plasmids having molecular size of 45, 32.8, 4.9, and 4.6 kilobases (kb). Single- and double-restriction endonuclease digestion by Ava I and Nde I indicated that the size of the additional plasmid carried by the nonpiliated form of IBH64 was approximately 43.6 kb. The M bovis isolates, Newport and GRS, contained the same number of plasmids in either their piliated or nonpiliated form.