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Biomedical subjects

G E Ward

Publications and source records attributed to G E Ward.

At least 55 records · Page 3Linked to original sources
PubMed1984

Immunofluorescent demonstration of Campylobacter hyointestinalis and Campylobacter sputorum subsp mucosalis in swine intestines with lesions of proliferative enteritis.

An indirect fluorescent antibody technique was developed to identify Campylobacter spp in lesions of swine proliferative enteritis (SPE). Rabbit antisera to C hyointestinalis and C sputorum subsp mucosalis were produced. Bacterial smears stained by fluorescent antibody test with homologous antisera differentiated C hyointestinalis from subsp mucosalis. Ileal frozen sections from 29 pigs with histologic lesions of SPE had specific fluorescent staining of C hyointestinalis in all 29 and subsp mucosalis in 24. Bacterial structures of C hyointestinalis were seen in large numbers and were broadly distributed in intestinal luminal exudate, mucosal necrotic tissues, surface epithelium, lamina propria, and proliferative cryptal epithelium. Numerous C hyointestinalis organisms were always present in the apical cytoplasm of proliferative cryptal epithelium. Fluorescent subsp mucosalis bacteria were seen less frequently and were distributed focally in the mucosa. Numerous subsp mucosalis organisms were more common in cellular debris and in necrotic tissues of surface mucosa, and less common in the epithelial cells of proliferative crypts. Ileal sections from 13 pigs without SPE had no fluorescent staining of C hyointestinalis and subsp mucosalis.

Animals↗
PubMed1984

Morphologic features, structure, and adherence to bovine turbinate cells of three haemophilus somnus variants.

Three colony variants (translucent, small opaque, and large opaque) of Haemophilus somnus recovered during infection studies of chicken embryos were examined using electron microscopy. Ruthenium red-strained H somnus preparations revealed no capsule in any variants. Pili were not seen on phosphotungstate-negative stained preparations. The translucent variant was thin-walled and had an irregular, pleomorphic rod shape. The small opaque variant had a thicker cell wall and an even rod shape. The large opaque variant had the thickest, most rigid wall of the 3, with uniform rod morphologic features. When each of the 3 variants was allowed to contact bovine epithelial turbinate cells, the translucent and small opaque were significantly (P less than 0.01) more adherent than was the large opaque variant.

Animals↗
PubMed1983

The increased phosphorylation of ribosomal protein S6 in Arbacia punctulata is not a universal event in the activation of sea urchin eggs.

Eggs of the sea urchins Arbacia punctulata (Ap), Lytechinus pictus (Lp), and Strongylocentrotus purpuratus (Sp) were labeled to equilibrium with 32PO3-4. Approximately 65-70% of the label in extractable adenine nucleotides comigrates chromatographically with ATP. Autoradiograms of one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) slab gels show that each species possesses a distinct complement of phosphate-exchangeable phosphoproteins. No changes in the phosphoprotein composition are detected in Lp and Sp eggs as a result of fertilization or development for 2.5 hr (with the possible exception of a 43,000 Mr protein in Lp). In Ap, increases in the phosphorylation of bands at Mr's 30,000, 55,000, and 105,000 are seen during the first 10 min postinsemination. The 30,000 Mr band in Ap eggs has previously been identified as ribosomal protein S6 and the hypothesis presented that its increased phosphorylation may be an important step in the activation of protein synthesis at fertilization (D. G. Ballinger and T. Hunt, 1981, Dev. Biol. 87, 277-285). In Lp and Sp eggs S6 (identified by two-dimensional PAGE) is heavily phosphorylated in the unfertilized state and the extent of labeling does not increase after fertilization. If the increased phosphorylation of S6 seen in Ap is indeed related to translational activation, then these results suggest that different sea urchin species may rely on different mechanisms for the activation of protein synthesis.

Animals↗
PubMed1983

Dephosphorylation of a major sperm membrane protein is induced by egg jelly during sea urchin fertilization.

A 160-kilodalton (kDa) protein of Arbacia punctulata sperm is constitutively phosphorylated on serine residues, as shown by in vivo(32)PO(4) (3-) labeling. Exposure of sperm to solubilized egg jelly results in the immediate dephosphorylation (within 5 sec) of this protein and a simultaneous increase in its electrophoretic mobility (to an apparent molecular mass of 150 kDa). In its dephosphorylated form (150 kDa), the protein is a major component of the flagellar plasma membrane. In fact, silver-stained polyacrylamide gels show the 160/150-kDa protein to be the third most abundant protein in the whole flagellum. The spermatozoan must pass through the egg jelly layer on its way to the egg surface. The jelly-induced dephosphorylation of such an abundant sperm membrane protein may be an important event in the successful interaction of sperm and egg during fertilization.

Journal Article↗
PubMed1983

Campylobacter hyointestinalis (new species) isolated from swine with lesions of proliferative ileitis.

Intestines from 48 swine with enteric disease were examined by bacteriologic cultural technique for the presence of various Campylobacter species. Histopathologic techniques were used to determine whether the submitted specimens had lesions of either swine proliferative ileitis or other enteric diseases. Three species of Campylobacter were identified as Campylobacter jejuni/coli, Campylobacter sputorum ss mucosalis, and Campylobacter hyointestinalis (proposed new species) on the basis of biochemical characteristics and response to various inhibitory substances. The C hyointestinalis was isolated from 18 of 27 (67%) swine with proliferative ileitis and from only 1 of 21 (5%) swine with other enteric diseases. The C sputorum ss mucosalis was obtained from 16 of 27 (59%) swine with proliferative ileitis and from 2 of 21 (10%) swine with other enteric disease. The C jejuni/coli was isolated from 2 of 27 (7%) swine with proliferative ileitis and from 8 of 21 (38%) swine with other enteric disease. The new organism, C hyointestinalis, was catalase-positive, hydrogen sulfide positive in triple sugar iron agar, glycine tolerant, intolerant to 3.0% sodium chloride, able to grow at 25 C, sensitive to cephalothin, and resistant to nalidixic acid. On the basis of these characteristics, C hyointestinalis was differentiated from other campylobacters isolated from swine and from other sources.

Animals↗
PubMed1982

Effects of dietary milk fat (whole milk) and propionic acid on intestinal coliforms and lactobacilli in calves.

Calves fed whole milk had 2,000-fold fewer (P less than 0.001) coliforms in the cranial part of the small intestine than did calves fed skim milk (fat removed). Calves fed milk with 32 mM added propionic acid had nearly 1,000-fold lower (P less than 0.001) counts of lactobacilli in the entire gastrointestinal tract than did calves fed milk without added propionic acid.

Abomasum↗
PubMed1982

Model infection of the chicken embryo with Haemophilus somnus.

Infectious thromboembolic meningoencephalitis of cattle which is caused by Haemophilus somnus has been difficult to study due, in part, to lack of model infection in a laboratory animal. Model infection was induced in 12-day-old chicken embryos after IV injection of H somnus. Death with typical lesions (hemorrhage, degeneration of brain, congestion of venules with leukocytes and meningitis) was seen in the chicken embryo between 2 and 6 days after injection of organisms. Bacteria could be demonstrated in lesions, using Warthin-Starry silver strain. Three stable colonial variants of H somnus were cultured from dead embryos. They appeared as small translucent (ST), small opaque (SO), and large opaque (LO). Lethal dose50 values of ST was 4.4 x 10(4); for SO, 3.6 x 10(4); and for LO, 8 x 10(6). Statistical analysis indicated that ST and SO were significantly more lethal (P less than 0.001) than LO.

Animals↗
PubMed1981

Mannitol agar for microbiologic diagnosis of bovine mastitis.

A medium containing mannitol (mannitol agar) was developed and evaluated as a tool for the microbiologic diagnosis of bovine mastitis. Mannitol agar supported growth of all important bacterial mastitis pathogens (staphylococci, streptococci, coliforms, and pseudomonads) except Corynebacterium pyogenes. Color change around colonies in the agar permitted the differentiation of pathogenic from nonpathogenic staphylococci. Most Staphylococcus aureus strains and some Staphylococcus epidermidis strains produced yellow zones. These yellow zone-producing strains (mannitol fermenters) of staphylococci were obtained from quarters with significantly elevated (P less than 0.05) somatic cell counts (SCC) in the milk, as compared with uninfected quarters and, therefore, would be considered pathogens. Mannitol-negative strains of S epidermidis (those with red zones) were obtained from quarters with SCC similar to those of uninfected quarters. The streptococci could be divided into 2 groups on the basis of color change around the colonies: Streptococcus agalactiae, Str dysgalactiae, and group G streptococci produced red zones; Str uberis, Str bovis, and enterococci produced yellow zones. Pathogenic streptococci (Str agalactiae, Str dysgalactiae, Str uberis, and group G streptococci) were obtained from quarters with SCC significantly higher (P less than 0.01) than those of uninfected quarters. Streptococcus bovis and enterococci were obtained from quarters with SCC similar to those of uninfected quarters and were considered nonpathogenic. Pathogenic streptococci were found in much higher concentration than nonpathogenic streptococci and could be differentiated on that basis.

Animals↗
PubMed1981

Effects of storage time and temperature on quantitative culture of canine urine.

Results of quantitative culture of 25 canine urine samples stored at different temperatures for varying periods (2, 4, 6, 12, and 24 hours) following collection were compared. Samples stored at room temperature (21 to 25 C) were unreliable for diagnostic quantitative culture after 24 hours. False-positive results were obtained in 13 (50%) of the samples, and false-negative results were obtained in 1 (4%) sample. Likewise, samples sent via the US mail were unreliable for diagnostic quantitative culture since false-positive results were obtained in 9 (35%) of the samples. Samples stored at refrigeration temperature (3 to 8 C) provided more satisfactory data. Culture of urine samples refrigerated for 2 hours resulted in quantitative results that were similar and interpretations that were identical to those obtained for samples cultured without having been refrigerated. Refrigeration for periods up to 6 hours resulted in qualitative counts that differed from those obtained after initial culture of the nonrefrigerated samples, but interpretations of results were identical. After 24 hours of refrigeration there were no false-positive results; however, false-negative results were observed in 1 (4%) of the samples. These observations indicated that optimal results of quantitative culture of urine can be consistently obtained only if samples are immediately processed following collection. If immediate culture is not possible, the specimens may be stored for at least 6 hours at refrigeration temperature without compromising the validity of results.

Animals↗
PubMed1981

Use of cystine, lactose, electrolyte-deficient medium for isolation and identification of bacteria and yeasts from the skin and ears of dogs.

Cystine, lactose, electrolyte-deficient (CLED) medium, a culture medium used for isolation and identification of bacteria from the urinary tract of human beings, was evaluated in a clinical setting for isolation and identification of bacteria and yeasts from the skin and ears of dogs. Staphylococci, streptococci, Pseudomonas sp, Proteus sp, and Candida sp were isolated in cases of secondary pyoderma, otitis, demodectic mange, and folliculitis in 50 dogs. Proteus sp was found along with other organisms in 5 cases. Spreading of Proteus sp was prevented by the CLED medium, permitting isolation of the other pathogenic organisms. Observations of growth characteristics on CLED medium and use of 4 additional simple laboratory procedures permitted correct identification of 90.3% of the isolates.

Animals↗
PubMed1981

Radiolabeled substrate assay to measure inhibition of growth of Haemophilus somnus by normal bovine serum.

An assay was developed to measure the inhibition of cell division of Haemophilus somnus by normal bovine serum. Dilution plate counts, turbidometric measurements, and release of radiolabeled cell constituents were found to be time-consuming or difficult to perform and reproduce. This assay determined the inhibitory effect of normal serum on population growth, by measuring the relative rate of macromolecular (DNA) synthesis in exponential cultures. This method was simple to perform and gave reliable results in 1 day. When this assay was used, a significant difference (P less than 0.025) in serum susceptibility was demonstrated between a H somnus isolate recovered from the trachea of a healthy calf and an isolate recovered at necropsy from a brain lesion of a cow. The implication of this finding, in relation to the pathogenicity of the organism, it briefly discussed.

Animals↗
PubMed1981

Somatic and capsular factors of coliforms which affect resistance to bovine serum bactericidal activity.

Killing of bacteria which cause acute coliform mastitis was studied in vitro, using serum without exogenous complement. Using 10% freshly collected whole serum, it was found that some strains were killed rapidly and could be classified as serum sensitive and others were killed less rapidly and could be classified as intermediate serum sensitive. With other strains, fewer were killed, and then the survivors multiplied; these could be classified as serum resistant. A 50-percentage kill of serum-resistant strains could not be achieved with serum (even in concentrations of greater than 90% serum), whereas 15 strains showed 50-percentage kill at appropriate serum concentrations. Resistance of Escherichia coli to serum bactericidal activity was greatest in strains with large amounts of heat-labile capsule present. The capsule could be demonstrated, using a test for somatic inagglutinability and a hemagglutination-inhibition test. Resistance of Klebsiella pneumoniae to serum bactericidal activity was not related to somatic inagglutinability. In K pneumoniae, resistance to serum bactericidal activity was related to presence of somatic antigens on the resistant strain.

Agglutination↗
PubMed1981

In vitro phagocytosis and killing of coliforms by bovine mammary leukocytes.

Four coliform isolates derived from cows with bovine mastitis-1 serum-sensitive (SS) Klebsiella pneumoniae, 1 intermediate serum-sensitive (IS) K pneumoniae, 1 IS Escherichia coli, and 1 serum-resistant (SR) E coli-were studied in vitro to determine factors associated with their phagocytosis and killing by leukocytes of mammae. The SS coliform was most easily phagocytosed, whereas the SR coliform was the least phagocytosed, and IS coliforms were ingested at an intermediate rate. The SS coliform was more readily killed in freshly collected serum alone, than by leukocytes and freshly collected serum or heat-inactivated serum. The IS coliforms were killed more readily by leukocytes with freshly collected serum, than by freshly collected serum alone or leukocytes and heat-inactivated serum. The extent of the killing of SR strain was equal for leukocytes with either freshly collected serum or heat-inactivated serum. The differences in killing of various coliforms in serum alone were not as great in a system including serum and leukocytes.

Animals↗
PubMed1980

Kinetics of interaction and fate of Pasteurella hemolytica in bovine alveolar macrophages.

To study the role of pulmonary alveolar macrophages (PAMs) in phagocytizing Pasteurella hemolytica, we developed an in vitro cultivation method for preparing them. This procedure provided an adherent monolayer of PAMs which were nonspecific esterase-positive and phagocytized latex beads. The phagocytosis and fate of P. hemolytica (biotype A, serotype 1) by PAMs in suspension were studied. The kinetics of phagocytosis were determined by quantitatively measuring the uptake of 24-h [(3)H]thymidine-labeled bacteria by the PAMs in the presence of opsonins. Results showed that the uptake of P. hemolytica was enhanced in the presence of normal serum or antiserum. A total of 90% of the bacteria were phagocytized in the presence of normal adult bovine serum, and up to 95% were phagocytized in the presence of an antiserum. These studies also showed that normal serum, but not fetal calf serum, contained heat-stable natural antibodies which readily initiated the opsonization of P. hemolytica. The heat-labile complement system was also involved in the opsonization. The fate of P. hemolytica inside the PAMs was investigated by transmission electron microscopy and by the viable plate count method. Approximately 90% of the normal serum- or antiserum-opsonized P. hemolytica were phagocytized by PAMs at a bacteria/PAM ratio of 20:1 and were completely degraded after 60 min of exposure. Prolonged incubation of this mixture of bacteria and PAMs resulted in cytotoxic changes and destruction of PAMs. At a low bacteria/PAM ratio (10:1 or less), there was phagocytosis and killing of bacteria but no cytotoxic changes on the PAMs. The exact mechanism which initiated this phenomenon was not demonstrated. Perhaps toxic substance(s) released by the excess unphagocytized bacteria caused the cytotoxic changes to the PAMs.

Animals↗
PubMed1980

Adverse effects caused by polypropylene and polyvinyl feline urinary catheters.

Effects of 3 days of open dwelling urethral catheterization were evaluated in normal male cats. Commercially manufactured polypropylene and polyvinyl feline urinary catheters of sufficient length to permit constant urine drainage were compared. Catheters were similar in length, diameter, and design. Hematuria occurred in 6 of 6 cats with polypropylene catheters and in 4 of 6 cats with polyvinyl catheters. For cats with polypropylene catheters, hematuria began within 24 hours of catheter insertion. Hematuria induced by polypropylene catheters was usually more severe in final urinalyses than that induced by polyvinyl catheters. Catheter-induced bacteriuria was found in 5 of 6 cats with polypropylene catheters and in 3 of 6 cats with polyvinyl catheters. Staphylococci and streptococci were the most common bacterial isolates. Microscopic lesions in urethras and bladders were significantly less severe in cats with polyvinyl catheters than cats with polypropylene catheters. With few exceptions, urethras of cats with polyvinyl catheters were microscopically indistinguishable from urethras of noncatheterized cats. Polypropylene catheters consistently induced urethritis which was most severe in some bacteriuric cats. Severe lesions were found in the bladders of all cats with polypropylene catheters. Bladder lesions were common in cats with polyvinyl catheters, but were usually less severe in cats with polypropylene catheters. There was no apparent relation between bacteriuria and bladder lesions.

Animals↗