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Biomedical subjects

H D Hilley

Publications and source records attributed to H D Hilley.

17 recordsLinked to original sources
PubMed1989

Degeneration of cartilage canal vessels associated with lesions of osteochondrosis in swine.

Articular-epiphyseal cartilage complexes from the distal femur and humerus of five 3-month-old pigs were collected and preserved using either a conventional or a ruthenium hexammine trichloride (RHT)-supplemented fixation technique. Lesions were similar regardless of the fixation technique. Areas of necrosis were in epiphyseal but not articular cartilage from both sites of all pigs. Cartilage canals were confined to epiphyseal cartilage and contained vessels which had endothelial cells in varying stages of degeneration and necrosis. Areas of necrotic cartilage often were adjacent to or surrounded degenerate cartilage canals. Lipid emboli (up to 40.0 micron in diameter) were infrequently located in vessels within cartilage canals. Associated with the lipid emboli were leukocytes, erythrocytes, necrotic cell remnants, and flocculent material. Restriction of necrosis to epiphyseal cartilage and the association of these necrotic areas with degenerating vessels in cartilage canals strongly implicate a defect in cartilage canal blood supply in the pathogenesis of osteochondrosis. The RHT fixation technique resulted in excellent cellular detail at the light microscopic level, but ultrastructurally there was marked vacuolation of chondrocytes and matrix. The conventional technique caused shrinkage of all chondrocytes, resulting in a wide halo of pericellular matrix surrounding each cell.

Animals↗
PubMed1988

Effect of reduced growth rate on the prevalence and severity of osteochondrosis in gilts.

Ninety-six recently weaned gilts were assigned to 3 groups. Group-1 gilts were fed a corn-soybean meal diet ad libitum and were killed when they weighed 110 kg. Gilts in groups 2 and 3 were fed 70% of the feed consumed by group-1 gilts. Group-2 gilts were killed when they weighed 110 kg, and group-3 gilts were killed at the same age as group-1 gilts. At slaughter, the right pelvic and thoracic limbs from all gilts were removed, and the distal end of each femur and humerus was sectioned serially at 5-mm intervals. Articular-epiphyseal cartilage complexes from these sites were examined grossly, radiographically, and histologically. Effects of treatment (ad libitum vs limited energy intake) and average daily gain on the prevalence and severity of lesions were analyzed statistically, using chi 2 analysis, a categoric-modeling technique, analysis of variance, and correlation coefficients. Of humeri and femora, 49 and 70%, respectively, had lesions of osteochondrosis, and 86% of the gilts had a lesion at one or both sites. Group-2 gilts (killed at 110 kg, but approx 70 days older than group-1 gilts) had significantly lower prevalence (P = 0.009) and severity (P = 0.002) of osteochondrosis of the distal end of the femur than did gilts in groups 1 and 3. When each group was evaluated individually, gilts that had a higher average daily gain had an increased prevalence and severity of lesions.

Animal Feed↗
PubMed1987

Oxytocin precipitation of prostaglandin-induced farrowing in swine: determination of the optimal dose of oxytocin and optimal interval between prostaglandin F2 alpha and oxytocin.

The influence of dose of oxytocin and the interval between prostaglandin (PG) F2 alpha and oxytocin administration on the synchrony of farrowing, the prevalence of intrapartum complications, and the number of pigs dying perinatally was investigated. In study 1, sows were given 10 mg of PGF2 alpha IM on day 112, 113, or 114 of gestation or were not treated. Twenty hours after PGF2 alpha administration, sows were given 0, 5, 10, 20, or 30 USP U of oxytocin IM. Sows treated with PGF2 alpha or PGF2 alpha plus oxytocin had a shorter interval to farrowing than sows not treated or treated with oxytocin alone. Treatment with PGF2 alpha plus 30 U of oxytocin induced the most rapid onset and the greatest synchrony of farrowing, with the mean onset occurring 2.1 +/- 0.4 hours after oxytocin vs greater than 8 hours for all other treatments. Sows treated with 5 or 10 U of oxytocin had a delayed onset and a less synchronous farrowing, compared with sows treated with 0 or 20 U. Day of PGF2 alpha treatment influenced (P less than 0.05) the interval from oxytocin to onset of farrowing. As day during gestation decreased, there was a corresponding decrease in the interval between oxytocin administration and farrowing. Number of interventions to remove retained pigs was not influenced (P greater than 0.05) by day of PGF2 alpha administration. All sows treated with PGF2 alpha followed by oxytocin had a higher rate of manual interventions, compared with that in sows given PGF2 alpha but not oxytocin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Histochemical morphologic features of growth cartilages in long bones of pigs of various ages.

Growth cartilages were obtained from humeri, femora, and ulnae of 31 pigs between 1 and 169 days old. On the basis of stain uptake and distribution, distinct layers were identified in articular-epiphyseal cartilage complexes and growth plates. The laminated appearance was dependent on stain uptake by territorial and interterritorial matrices and was more distinct in pigs greater than 15 days old. There was morphologic heterogeneity, which probably represented a functional heterogeneity, among chondrocytes in all layers and zones of both types of growth cartilage. The laminar appearance of growth cartilages and the distribution of different types of cells were similar for all pigs in each age category and for all sites.

Aging↗
PubMed1986

The ultrastructure of osteochondrosis of the articular-epiphyseal cartilage complex in growing swine.

Osteochondrosis of the articular-epiphyseal cartilage complex (A-E complex) is a significant clinical disease in swine. It has been suggested that osteochondrosis is the underlying cause of osteochondritis dissecans in humans. The purpose of this investigation was to characterize the ultrastructural changes in the earliest macroscopically visible lesion of the epiphyseal cartilage in osteochondrosis of the A-E complex in swine. Osteochondritic epiphyseal cartilage from the distal femora and humeri of growing crossbred boars was collected, embedded in plastic, and studied light and electron microscopically. The predominant lesion was chondronecrosis, characterized by chondrocyte death and loss of matrical proteoglycan. Transition from normal to abnormal cartilage was abrupt. Lipid accumulated in chondrocytes within and adjacent to lesions, but not in chondrocytes distant from lesions. Intracellular lipid accumulation was an important feature of the lesion and may play a role in its initiation. It is hypothesized that intracellular lipid accumulation results from hypoxia/anoxia and may precede matrix degeneration, which precedes cell death.

Animals↗
PubMed1985

Dyschondroplasias of growth cartilages (osteochondrosis) in crossbred commercial pigs at one and 15 days of age: radiological, angiomicrographical and histological findings.

The age of onset and morphology of the earliest lesions of dyschondroplasias in pigs have not been established. Bones and growth cartilages from pigs were examined for the presence of lesions using radiological, angiomicrographical and histological techniques. Lesions were in 10 of 11 pigs at 15 days of age and 12 of 21 pigs at one day of age, indicating that the condition was congenital. The simplest and apparently earliest lesion was an area of persistent hypertrophied chondrocytes and matrix which extended from the articular-epiphyseal complex or physis into the epiphysis or metaphysis, respectively. Since the prevalence of lesions was high it was considered that the dyschondroplasia may be part of the usual growth pattern of cartilages in contemporary pigs.

Animals↗
PubMed1985

Ultrastructure of normal epiphyseal cartilage of the articular-epiphyseal cartilage complex in growing swine.

Normal epiphyseal cartilage from the articular-epiphyseal cartilage complex (A-E complex) of the distal parts of the femur and humerus of growing commercial crossbred boars was collected, embedded in plastic, and studied by light and electron microscopies. The morphology of this cartilage was determined to provide a basis for comparison with cartilage affected with osteochondrosis, an important clinical disease in swine. Normal epiphyseal cartilage from the A-E complex in growing swine was divided into 4 major regions of cells: resting, proliferating, hypertrophic, and calcifying regions. Cells in the resting zone contained prominent lipid and densely aggregated glycogen. As the cells proliferated and matured, the lipid and glycogen became less prominent. The lipid droplets became smaller and scarcer, and the glycogen became dispersed in the cytoplasm. Proliferating and hypertrophic cells clustered in roughly egg-shaped groups of 4 to 8 cells/plane of section. In the calcifying region, the interterritorial matrix (between cell clusters) calcified, and the territorial matrix (uniting cells in a cluster) remained uncalcified. Calcified matrix extended the depth of one cell group from the area of capillary penetration, and the capillaries invaded by entering a cluster of cells. Territorial matrices in all regions of A-E complex epiphyseal cartilage were composed of randomly oriented collagen fibrils with a granular fibrillar proteoglycan network dispersed between the fibrils. Heterogeneity of chondrocytes was characterized by the presence of both light- and dark-staining cells in the proliferating through calcifying regions and by 3 morphologically distinct light cell types in the late hypertrophic and calcifying regions.

Aging↗
PubMed1985

Microorganisms associated with pneumonia in slaughter weight swine.

The lungs of 334 pigs were obtained from two slaughter plants in Minnesota and examined in detail. Macroscopic and microscopic evaluation, direct fluorescence for Mycoplasma hyopneumoniae and bacterial culture were done on all of them and a subsample of 50 were selected for virus culture. Mycoplasma hyopneumoniae, Pasteurella multocida and Haemophilus spp. were detected in 24.0%, 34.1% and 27.0% of the lungs, commonly in conjunction with each other. One isolate of Haemophilus pleuropneumoniae serotype 2 was detected and this represents the first report of its presence in the United States. No virus was detected in any of the lungs. Lungs with both M. hyopneumoniae and Pasteurella multocida had the greatest amount of macroscopic pneumonia (9.8% of the lung). Lungs with M. hyopneumoniae or P. multocida alone had 4.9% and 5.2% of the lung involved with pneumonia respectively. Lungs with Haemophilus sp. Taxon "minor group" had 3.8% of the lung involved which was not significantly different from lungs with none of these organisms being detected (1.6%). There was a positive correlation between the extent of M. hyopneumoniae infection, as scored by FAT and the amount of macroscopic pneumonia present (r = 0.46; P less than 0.001). Likewise, there was a positive correlation between the estimated concentration of P. multocida present, as scored by the relative number of colonies on blood agar and the amount of macroscopic pneumonia present (r = 0.60; P less than 0.001). Microscopically, the amount of lymphoreticular proliferation, polymorphonuclear cells and alveolar macrophages were evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)

Abattoirs↗
PubMed1984

An ultrastructural analysis of osteochondritic growth plate cartilage in growing swine.

In growing swine, ossification failure due to osteochondrosis has an incidence of nearly 100% in the distal ulna of animals at six months of age, yet the etiology of the disease is understood poorly. In this study, the ultrastructure of the chondrocyte and its pericellular matrix is analyzed in normal growth plates and in growth plates with lesions characteristic of osteochondrosis using aldehyde primary fixatives and osmium-ferrocyanide as the secondary fixative. Chondrocytes in lesion areas fail to undergo normal hypertrophic cell maturation, and they have an accumulation of rough endoplasmic reticulum, lipid droplets and mitochondria. These morphological changes are interpreted to be both variable and nonspecific for osteochondrosis. Within the pericellular matrix of chondrocytes from lesion areas, the most striking abnormality is the presence of a highly condensed matrix with an accumulation of large, irregularly shaped deposits of electron dense material. These morphological alterations are characteristic of a matrix which either is not secreted normally, or in which the highly ordered interactions of diverse macromolecules has been lost. These pericellular matrix changes have not been described in other diseases of growing cartilage. They may be significant in the failure of metaphyseal vascular penetration of the pericellular matrix which is characteristic of osteochondrosis.

Animals↗
PubMed1984

Dyschondroplasias, including osteochondrosis, in boars between 25 and 169 days of age: histologic changes.

Microscopic sections of physeal and articular-epiphyseal (A-E) cartilages from major limb bones of 60 boars between 25 and 169 days of age were examined. The objectives in this study were to determine the age of onset and pathogenesis of osteochondrosis, a defect of endochondral ossification. Lesions regarded as typical of osteochondrosis were associated with physes of pigs from 25 days of age, indicating an earlier age of onset than has generally been documented. Two morphologically distinct lesions were observed, but both had areas with increased depth of the zone of hypertrophying chondrocytes. Some lesions were repairing. With increasing age of the pigs, the number of involved physes increased in each of 6 different age groups up to 169 days. Lesions associated with physes were observed in boars younger than those with lesions associated with A-E complexes. A few pigs at, or older than, 53 days of age, had osteochondrosis-like lesions involving epiphyseal growth cartilages. However, a dyschondroplasia different from osteochondrosis and typified by chondrolysis was more frequently associated with A-E complexes of pigs at or greater than 79 days of age. The number of affected cartilages and sites with this type of lesion also increased with age. Although osteoarthrosis had not developed in any of the pigs, it is probable that chondrolytic areas were precursors of degenerative joint disease. To date, osteochondrosis has been used to encompass lesions involving physes and A-E complexes. However, in view of the findings in the present study, dyschondroplasia is the preferred term to be used generically and then qualified by morphologic description, since causations may be different.

Aging↗
PubMed1984

Dyschondroplasias, including osteochondrosis, in boars between 25 and 169 days of age: radiologic changes.

Boars in 6 different groups (between 25 and 169 days of age) were examined radiographically to determine the age of onset of lesions associated with the sites of endochondral ossification in limb bones. Although lesions were in histopathologic sections of physes from all groups of pigs, they were not found frequently in radiographs of live animals until boars were more than 100 days old. Microscopic lesions were infrequent in articular-epiphyseal (A-E) complexes of pigs less than 80 days old, and radiographic examination of live animals had limited value until animals were greater than 100 days old. Radiographs of slabs of bone were useful in the detection of physes with lesions in all age groups and A-E complexes with lesions in boars 100 days of age or older. So that the accuracy of radiographic examination of live animals for the diagnosis of dyschondroplasias could be evaluated, a comparison was made between the numbers of growth cartilages with lesions as determined by radiologic examination of live animals, radiographic examination of slabs of bone, and light microscopy (examination of tissue sections). Only 21% of the lesions associated with physes and 22% of the lesions associated with A-E complexes were detected in radiographs of bones of live pigs. The authors concluded that the latter method was inaccurate for the identification of dyschondroplastic foci. Identification of lesions by examination of radiographs of slabs of bone was only slightly more accurate, since 33% of physes and 23% of A-E complexes which had lesions were found. Potential errors in evaluation of radiographs were discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1983

Serotyping of Pasteurella multocida isolated from swine lungs collected at slaughter.

We serotyped 222 Pasteurella multocida strains isolated from swine lungs at slaughter. Capsular serotypes A and D were determined by the hyaluronidase sensitivity and acriflavin agglutination tests, respectively. Somatic antigens were determined by gel diffusion against standard antisera. Capsular serotype A was found in 97.3% of the strains and serotype D in the remaining 2.7%. The primary somatic antigen most commonly found was type 3 (86.0%). Type 5 was also very common (88.7%), but was usually a secondary antigen. The most common overall serotype was A:3(5) (39.2%). Other common serotypes were: A:3(4,5,12) (12.2%); A:3(4,5) (11.2%); A:3(5,12) (10.4%); A:3 (6.8%); and A:5 (6.8%). Type D strains had a similar distribution of serotypes, but with a higher prevalence of D:5 (33.3%) and D:3(5) (33.3%).

Animals↗
PubMed1983

Dilution technique for isolation of Haemophilus from swine lungs collected at slaughter.

A total of 307 lungs obtained from a slaughterhouse were cultured by a dilution technique for the isolation of Haemophilus spp. The technique consisted of performing serial (10-fold) dilutions of the tissue samples to a dilution of 10(-5). Two selective media were used. L broth consisted of a basal brain heart infusion broth containing 5% horse serum, 5% yeast extract, and 100 micrograms of NAD and 0.5 microgram of lincomycin per ml. L-B broth was identical to L broth, except 1.5 microgram of bacitracin per ml was included. The broths were incubated overnight and then plated onto blood agar. A total of 83 (27%) isolates were obtained, and both media proved to be necessary, as a proportion of isolates grew in one of the media employed but not in the other. Of the isolates, 66.3% were urease positive and most of these (98%) were classified as "minor group" strains. Urease-negative strains (27.7%) were classified as Haemophilus parasuis.

Animals↗
PubMed1981

Ultrastructural evidence of a functional heterogeneity among physeal chondrocytes in growing swine.

Chondrocytes from the distal ulnar physis of 1- and 5-month-old boars were studied by transmission electron microscopy. Among reserve, proliferating, and early hypertrophic chondrocytes, 2 distinct cell types (dark cells and light cells) were recognized, and in the distal proliferative and early hypertrophic regions, dark cells seemed to be involved in matrix vesicle production. Late hypertrophic light cells seemed to follow 2 lines of maturation. One pathway resulted in cells with a stellate shape, typical of hypertrophic cells in several species other than swine. A 2nd pathway resulted in large oval cells with water-clear cytoplasm. These cells appeared to become encased in a lamina of fine fibrils interspersed with irregularly shaped electron-dense material. The functional significance of these 2 pathways remains unclear.

Animals↗