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Biomedical subjects

N F Cheville

Publications and source records attributed to N F Cheville.

At least 73 records · Page 4Linked to original sources
PubMed1989

Ultrastructure and lectin histochemistry of equine cutaneous histiolymphocytic lymphosarcomas.

Tissues from subcutaneous lymphosarcomas and regional lymph nodes were examined by light and electron microscopy and by lectin histochemistry. Tumors were composed of two major cell types: small lymphocytes with few organelles and pleomorphic histiocytic cells with undulant surfaces, large numbers of cytoplasmic vacuoles, and many mitochondria with large crystalline inclusions. A large gram-positive coryneform bacterium was isolated from tumor nodules but was not identified morphologically in tumor tissues. Evaluation of sections of tumors with lectins as histochemical probes revealed three staining patterns: 1) lectin labeling histiocytic cells only (wheat germ, succinylated-wheat germ, Phaseolus vulgaris and soybean agglutinins); 2) lectins labeling histiocytic, interstitial and some lymphoid cells (concanavalin A, and Pisum sativum, Lens culinaris, and Ricinus communis I agglutinins); and 3) lectins failing to label any cell (peanut, Sophora japonica, and Ulex europaeus I agglutinins). In the lymph node, macrophages were labeled by lectins of groups 1 and 2; interdigitating reticular cells were labeled by group 2 lectins. Lectin staining of histiocytic cells in tumor tissues suggested that these were reactive cells and that lymphoid cells were the primary neoplastic component.

Animals↗
PubMed1989

Uptake and excretion of Brucella abortus in tissues of the face fly (Musca autumnalis).

To determine their capacity to host Brucella abortus, face flies were examined 1 to 120 hours after feeding on broth containing bacteria and bovine erythrocytes. Brucella abortus was cultured in large numbers from whole flies for 12 hours after feeding, but not after 72 hours. Histologic analysis showed that brucellae were rapidly taken into the midgut, sequestered from erythrocytes, transiently stored, and shed in the feces; there was no evidence of bacterial replication within epithelial cells. Immunoperoxidase and immunogold techniques revealed that most brucellae in the gut were confined to the lumen by the peritrophic membrane, that brucellae were degraded in secondary lysosomes of midgut epithelial cells, and that intact brucellae passed into connective tissues surrounding the midgut. Bacterial excretion without midgut replication is consistent with transient, but not long-term, insect transmission in nature.

Animals↗
PubMed1988

Bovine ileal dome lymphoepithelial cells: endocytosis and transport of Brucella abortus strain 19.

Ligated ileal loops of calves were inoculated with Brucella abortus and examined at 2, 4, 6, 10, and 24 hours post-inoculation. B. abortus was identified by light and electron microscopy using immunoperoxidase and antibody-coated colloidal gold techniques. B. abortus was detected in vesicles, phagolysosomes, and large vacuoles of lymphoepithelial cells. Numbers of intracellular bacteria decreased with time after inoculation. B. abortus was also seen between and below lymphoepithelial cells and free in the dome interstitium and intestinal lymph vessels. Neutrophils and macrophages in both epithelium and lamina propria contained intact or degraded bacteria within phagosomes, phagolysosomes, and multivesicular bodies. These studies showed that (1) transepithelial migration of B. abortus occurred principally by dome lymphoepithelial cell endocytosis and transport, and (2) B. abortus was degraded by macrophages and neutrophils of the gut-associated lymphoid tissue.

Animals↗
PubMed1988

Role of M cells and macrophages in the entrance of Mycobacterium paratuberculosis into domes of ileal Peyer's patches in calves.

Ligated ileal loops of calves were inoculated with live and heat-killed Mycobacterium paratuberculosis and were examined by light and electron microscopy. At 5 hours after inoculation, acid-fast bacilli were in subepithelial macrophages, but not in M cells covering domes. At 20 hours, more than 50 acid-fast bacilli per cross section were in subepithelial macrophages in domes. Both living and heat-killed bacilli passed into domes. Addition of anti-M. paratuberculosis bovine serum to the inoculum enhanced entry of bacteria into domes. By electron microscopy, intact bacilli with electron-transparent zones (peribacillary spaces) were in the supranuclear cytoplasm of M cells at 20 hours. M cells also contained vacuoles, including electron-dense material interpreted as degraded bacilli. Subepithelial and intraepithelial macrophages contained bacilli and degraded bacterial material in phagosomes. These results suggest that calf ileal M cells take up bacilli, and that subepithelial and intraepithelial macrophages secondarily accept bacilli or bacterial debris which are expelled from M cells.

Animals↗
PubMed1988

Pathogenesis of Brucella abortus in chicken embryos.

Chicken embryos inoculated with Brucella abortus at 6, 10, and 12 days of incubation were examined by light and electron microscopy. B. abortus was identified by avidin-biotin immunoperoxidase and immunogold techniques. Death occurred from 2 to 5 days post-inoculation, depending on age of the embryo and route of inoculation. B. abortus was recovered from all infected eggs. Brucellae had spread throughout all tissues and localized preferentially within cells of mesodermal derivation. Organ distribution and degree of bacterial replication varied with age of the embryo at time of inoculation. In 6-day-old embryos, B. abortus localized preferentially in endoderm and mesoderm of yolk sac wall, extra- and intraembryonic serosal epithelia, and glomeruli of the mesonephros. In 10- and 12-day-old embryos, B. abortus spread to all tissues; renal glomeruli, liver, spleen, and heart were most severely infected. Intracellular B. abortus was within the rough endoplasmic reticulum of mesenchymal, mesothelial, yolk endodermal, and hepatic cells. In mononuclear phagocytes, endothelial cells, and granulocytes, bacteria were within membrane-bound vacuoles. Intracellular replication of B. abortus in embryonic tissues, especially yolk endoderm, closely resembled that in experimental infections of trophoblasts.

Animals↗
PubMed1988

Acute fibrinopurulent blepharitis and conjunctivitis associated with Staphylococcus hyicus, Escherichia coli, and Streptococcus sp. in chickens and turkeys.

Multiple outbreaks of acute severe fibrinopurulent lesions of the eyelids occurred in chickens and turkeys. Lesions began as tiny foci of epidermal necrosis and ulceration and spread to involve the entire eyelid. Scabs overlying the epidermis contained large gram-positive cocci; lesser numbers of small cocci and gram-negative bacilli were in more superficial areas. Staphylococcus hyicus was isolated from birds in all stages of the disease. Escherichia coli and Streptococcus sp. were isolated only during severe stages; no anaerobic bacterial pathogens were isolated. Vasculitis and perivascular lymphocytic infiltrates in deep layers of the dermis suggested that a staphylococcal toxin may have been involved. The disease was not reproduced by scarifying S. hyicus onto the eyelids or by intravenous inoculation of retrovirus-infected chickens.

Animals↗
PubMed1988

Gut-associated lymphoid tissue in the large intestine of calves. II. Electron microscopy.

Scanning electron microscopy of lymphoid tissue in the large intestine of three germfree calves (age 3, 6, and 7 days) revealed two different units: propria nodules and lymphoglandular complexes (LGC). Propria nodules had lymphoid tissue predominantly in lamina propria and were covered by distinct follicle-associated epithelium which lacked goblet cells; nodules were surrounded by wide crypts, which were also lined by follicle-associated epithelium towards the luminal side. Lymphoglandular complexes had lymphoid follicles in the tunica submucosa; epithelial diverticulae extended through the muscularis mucosae branching into the lymphoid nodule. In centers of lymphoglandular complexes, protrusions of lymphoid tissue were covered with distinct follicle-associated epithelium. By transmission electron microscopy cells compatible with M cells in the small intestine of calves and cells with characteristics of both enteroabsorptive and M cells were found. Follicle-associated epithelium of propria nodules and lymphoglandular complexes differed only in the relative frequency of cell types.

Animals↗
PubMed1987

Postnatal colonization of porcine lung capillaries by intravascular macrophages: an ultrastructural, morphometric analysis.

Lungs of newborn and of 7- and 30-day-old pigs were fixed at total capacity by a standardized procedure. Stereologic morphometry was applied to random ultrathin sections of parenchyma. Relative volume density, absolute volume, and capillary surface coverage of intravascular macrophages as well as parameters of relative morphometric diffusion capacity of lungs were assessed. Intravascular macrophages occupied up to 25% of capillary volume in 30-day-old pigs compared with 6% in newborn pigs; this was a 14-fold increase of absolute volume. In 30-day-old pigs, 16% of capillary surface was covered with closely adherent intravascular macrophages in contrast to only 2% in newborn pigs. Determinators of morphometric diffusion capacity were similar in all pigs. Greater thickness of the arithmetic and harmonic mean air-blood tissue barrier in 30-day-old pigs (with included thickness of intravascular macrophages) compared with air-blood tissue barriers (without intravascular macrophages) was not statistically significant. The relative difference of arithmetic mean was larger than the difference of harmonic mean, and reflected preferential adherence of intravascular macrophages to the thick portion of the air-blood tissue barrier. Our findings confirm morphologic observations of perinatal colonization of the porcine lung by monocytes that replicate and differentiate into large, highly phagocytic, resident, intravascular macrophages. Preferential adherence to sites where basal laminae of capillary endothelium and alveolar epithelium were separated by interstitium may explain the minimal morphometric impact of intravascular macrophages on the air-blood tissue barrier thickness. This location would be expected to have less effect on gas diffusion than location of intravascular macrophages on the thin side of the air-blood barrier.

Animals↗
PubMed1987

Effect of Rous associated virus number 7 on lymphoid cells and tissues of the chicken.

Infection of chicks or chick embryos with Rous associated virus number 7 (RAV-7) led to a decreased blastogenic response to Concanavalin A (Con A) by lymphocytes isolated from the spleen and thymus. Chicks infected with RAV-7 8 days after hatch manifested decreased Con A blastogenesis 5 weeks postinfection, while chicks infected in ovo at 10 days of incubation showed an unusual pattern of cell density dependent decreased blastogenesis two weeks post-hatch (three weeks post-infection). Histopathological examination of tissues from RAV-7 infected chicks revealed evidence of lymphoid organ involution and widespread lymphoproliferative lesions by 3 weeks of age. The combination of decreased in vitro lymphoid blastogenesis and in vivo lymphoproliferation suggests that RAV-7 interacts with lymphocytes in a fashion that has not previously been described in the chicken.

Animals↗
PubMed1987

Pathogenesis of corneal lesions caused by Moraxella bovis in gnotobiotic calves.

Moraxella bovis was instilled into the conjunctival sac of gnotobiotic calves and corneas were sampled serially after infection. Lesions developed in seven of eight infected calves, but were absent in a noninfected control calf. Histologically, M. bovis was first seen in foci of swollen epithelium and within basal epithelial cells adjacent to ulcers. Corneal ulcers were severe in later stages of infection; fibrin deposits, neutrophils, and bacteria were present in the stromas. Examination of early lesions by scanning electron microscopy showed M. bovis in pits on the surfaces of dark epithelial cells, enmeshed in degenerate epithelial cells and within erosions and an ulcer; in later samples, bacteria were rare. Ultrastructurally, M. bovis was seen in surface pits in superficial epithelial cell processes and within swollen epithelial cells. In stroma, M. bovis was frequently seen among collagen fibrils, within neutrophil phagosomes, and associated with cellular debris. This study demonstrates that a virulent strain of M. bovis can invade bovine corneal epithelial cells and can cause keratitis in the absence of injurious ultraviolet irradiation or other known predisposing environmental factors.

Animals↗
PubMed1987

Conjunctival lesions caused by Moraxella bovis in gnotobiotic calves.

Hemolytic Moraxella bovis was instilled into the conjunctival sac of gnotobiotic calves, and conjunctivae were sampled serially after infection. Bilateral lesions developed in seven of eight infected calves. Histologically, M. bovis was first seen within swollen epithelial cells near the lid margins and occasionally within superficial epithelium in other areas. Conjunctival erosions and ulcers were seen in later stages. Scanning electron microscopy showed M. bovis in pits on surfaces of epithelial cells and in erosions on palpebral conjunctivae; lesions were prominent near lid margins. By transmission electron microscopy, M. bovis was seen within swollen epithelial cells near lid margins; many epithelial cells had undergone cytolysis. This study demonstrates that virulent M. bovis can invade bovine conjunctival epithelial cells and cause conjunctivitis in the absence of injurious ultraviolet irradiation or other predisposing environmental factors.

Animals↗
PubMed1986

Pathogenesis of placentitis in the goat inoculated with Brucella abortus. I. Gross and histologic lesions.

Pregnant goats were given Brucella abortus intravenously or in uterine arteries, and tissues from the uterus and placentae were examined at various post-inoculation intervals to study mechanisms of placental infection. Placentitis was present by 5 days post-inoculation and abortions occurred within 11 days. B. abortus was identified in placentae by light microscopy and immunoperoxidase techniques. B. abortus was first seen in erythrophagocytic trophoblasts of the placentome. Subsequently, high numbers of B. abortus were seen in periplacentomal chorioallantoic trophoblasts. Trophoblast necrosis, chorioallantoic ulceration, and large numbers of B. abortus in chorionic villi were present in later stages of infection. These results suggest that entry and replication of B. abortus in trophoblasts precede placentome and fetal infection and that trophoblasts are the source of B. abortus for these tissues. Experimental caprine brucellosis closely resembles bovine and ovine brucellosis and it provides a model to study the intracellular development of B. abortus in trophoblasts.

Abortion, Veterinary↗
PubMed1986

Pathogenesis of placentitis in the goat inoculated with Brucella abortus. II. Ultrastructural studies.

Pregnant goats were inoculated intravenously or in uterine arteries with Brucella abortus, and tissues from the uterus and placenta were examined by electron microscopy. Identification of B. abortus in placentae was with antibody-coated colloidal gold. B. abortus was first seen in phagosomes of erythrophagocytic trophoblasts and in the rough endoplasmic reticulum of chorioallantoic trophoblasts. Subsequently, trophoblast necrosis and ulceration of chorioallantoic membranes were present. Coincidently, B. abortus was present in the lumen of placental capillaries. In late stages of infection, placental vasculitis was present, and placentomal trophoblasts were separated from maternal syncytial epithelium. In lesions with vasculitis, large numbers of B. abortus were in connective tissue of chorionic villi. Within the placentome, trophoblasts that lined chorionic villi contained no intracellular bacteria and were separated from B. abortus by intact basement membranes. These results suggest that bacteremic B. abortus is endocytosed by erythrophagocytic trophoblasts and that B. abortus replicates in the rough endoplasmic reticulum of chorioallantoic trophoblasts. Replication of brucellae in trophoblastic rough endoplasmic reticulum is unique; we believe that B. abortus may utilize endoplasmic reticulum for synthesis and glycosylation of bacterial membrane proteins or that B. abortus catabolizes trophoblast secretory proteins.

Abortion, Veterinary↗
PubMed1986

Pathology of vitamin D deficiency in growing turkeys.

Turkey poults were fed a vitamin D-deficient diet and examined for clinical signs and structural changes of bone and parathyroid glands. Vitamin D-deficient poults developed ricketic changes during days 10 to 14. Control poults (deficient diet plus vitamin D) did not develop rickets. In deficient poults, lengths of proliferating-prehypertrophied zones of growth plates increased significantly in the proximal tibiotarsus but were only slightly elongated in the distal tibiotarsus. Unmineralized hypertrophic chondrocyte zones increased in length rapidly in conjunction with a decrease in the length of mineralized hypertrophic degenerative zones; this occurred more rapidly in proximal than in distal tibiotarsus. Other ricketic changes included decreases in bone ash, total femoral bone ash (calcium, phosphorus, magnesium), bone length, and body weight. Plasma alkaline phosphatase was increased, calcium was normal, and phosphorus was normal or elevated. Parathyroids were hyperplastic and had foci of degeneration. Vitamin D3 metabolites 25OHD3, 1,25(OH)2D3, and 24,25(OH)2D3 were rapidly depleted. Increase in bone ash Ca/P ratios in deficient poults suggests that phosphorus may be selectively released from ricketic bone. Low 25OHD3 and 1,25(OH)2D3 of control poults early in the experiment suggests that 1,400 IU of vitamin D3/kg of feed may not be an adequate level of vitamin D3 for growing turkey poults.

Alkaline Phosphatase↗
PubMed1986

Ultrastructural morphometric investigation of early lesions in the pulmonary alveolar region of pigs during experimental swine influenza infection.

Experimental infection of specific-pathogen-free pigs with swine influenza virus by the intratracheal route resulted in a severe respiratory disease that closely resembled natural swine influenza in clinical course and pathologic lesions. Alveolar epithelial necrosis with sloughing of necrotic cells occurred from 24 to 96 hours after inoculation (p.i.) and was associated with alveolar edema and diffuse interstitial pneumonitis. The latter, initially of neutrophilic character, became histiocytic 48 hours p.i. Ultrastructural analysis of alveolar parenchyma disclosed viral replication in epithelial cells beginning at 5 hours p.i. and lasting to 96 hours. Budding of pleomorphic virus particles from the surface of alveolar epithelial cells and accumulation of viral proteins within the nucleus and cytoplasm of epithelial cells were seen. The extent of parenchymal lesions as quantified by stereologic morphometry within the whole lung was characterized by a marked relative and absolute volume increase of interalveolar septa and increased air-blood tissue barrier thickness. The volume increase of interalveolar septa was due to an increase of interstitial tissue volume by 85% in pigs at 96 hours p.i., compared with control pigs with similar lung volumes.

Animals↗
PubMed1986

Ultrastructural morphometric analysis of Brucella abortus-infected trophoblasts in experimental placentitis. Bacterial replication occurs in rough endoplasmic reticulum.

Trophoblasts in normal and Brucella abortus-infected caprine placentas were examined by ultrastructural morphometric analysis to establish structural relationships of B abortus with cytoplasmic organelles; brucellae were identified with colloidal gold-labeled anti-B abortus bovine IgG. Cytotrophoblasts had large numbers of B abortus in cisternae of rough endoplasmic reticulum; binucleate trophoblasts did not contain bacteria. In infected trophoblasts there was a significant hypertrophy of B abortus-filled rough endoplasmic reticulum (RER) and a corresponding reduction in normal-appearing RER. Volume and surface density of RER in trophoblasts were: normal placentas (control), 2.8% and 0.30 sq mu; infected placentas, 27.9% (27.4% of which contained B abortus) and 0.56 sq mu (cells containing B abortus) and 3.3% and 0.34 sq mu (cells not containing B abortus). These data suggest that B abortus replicates within the RER of trophoblasts, possibly for synthesis and glycosylation of bacterial membrane proteins.

Animals↗
PubMed1985

Morphometry of postnatal development in the porcine lung.

Alveolar regions of normal pig lungs (newborn to 60-day-old) were characterized morphometrically to provide a basis for comparison in future investigations of porcine respiratory diseases. Endotracheal installation of fixative was done to expand the lungs uniformly at total capacity. Differential effects of lobar variations were determined by stratified random sampling of lung lobes. A stereologic study was done by point and intersection counts on electron micrographs. At birth, the lungs were remarkably well developed. Relative alveolar and capillary surface densities and air-blood tissue barrier thicknesses were at adult levels. In allometric regressions, volumes and surfaces of lung components regressed directly to lung volume, but monoexponentially (to the 3/4 power) with body weight. In the first postnatal week, however, relative volume densities of cellular interstitium in septal tissue and of capillary lumina in parenchyma increased at statistically significant levels. Composition of lung parenchyma and septa was changed, although without statistically significant direct impact on parameters related to gas exchange. Type II pneumocytes had increased nuclear to cytoplasmic volume ratios in 7- to 14-day-old pigs, probably reflecting cell activation and increased surfactant production. Age (postnatal lung growth) created the most substantial variance of results; interanimal variation in pigs of the same age was less important and no consistent lobar variations were seen.

Animals↗