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Biomedical subjects

J C Anderson

Publications and source records attributed to J C Anderson.

At least 127 records · Page 7Linked to original sources
PubMed1985

The pathogenesis of a high-virulence and a low-virulence strain of Corynebacterium bovis in the mammary gland of the mouse.

A comparison was made of the pathogenesis of experimental mastitis in mice caused by a strain of Corynebacterium bovis (P3) isolated from clinical mastitis in the cow and a strain (NCDO 1930) isolated from the teat of a symptomless carrier cow. Strain NCDO 1930 elicited a neutrophil response which controlled the infection so that, after 6 to 8 days, 9 of 10 glands were sterile and one abscess was found. In contrast, the neutrophil response to strain P3 failed to control the infection and, by 6 to 8 days, 8 of 10 glands were infected and there were abscesses in 11 of 20 glands. The virulence of strain P3 was associated with its ability to colonize on and in milk fat globules, from which the organisms multiplied in the alveolar lumen irrespective of the neutrophil infiltration.

Animals↗
PubMed1985

The contribution of a capsule to survival of staphylococci within bovine neutrophils.

The encapsulated strain M of Staphylococcus aureus and the encapsulated strain 76 of S. simulans survived incubation with bovine neutrophils in media containing heated bovine serum 0.5% v/v or milk whey 10% v/v. With two unencapsulated strains of S. aureus, M12 and M60, less than 5% of the original inoculum survived. When the concentrations of bovine serum and milk whey were increased to 2% and 50% respectively, survival of the encapsulated strains was similar to that of the unencapsulated strains. The ability of skimmed milk 50% v/v to opsonise strain M was found in milk from 95% of 62 cows. The individual values for percentage intracellular survival of strains of S. aureus phagocytosed by bovine neutrophils in the presence of bovine serum 2% v/v or milk whey 50% v/v were 0.48, 0.30 and 0.24 for strains M60, M and M12 respectively. Intracellular survival of strain M60 was significantly greater than that of strains M12 and M. The encapsulated coagulase-negative strain 76 (S. simulans) was not susceptible to lysis by lysostaphin, and it was not possible to destroy extracellular staphylococci to measure intracellular survival. It is concluded that the capsule of S. aureus strain M does not contribute to intracellular survival.

Animals↗
PubMed1985

Ultrasound guided chorion biopsy in antenatal diagnosis of genetic disorders.

The technique of transcervical chorion biopsy was evaluated in women about to undergo therapeutic termination of pregnancy. The trophoblast biopsy catheter (Portex) under real-time ultrasound guidance was the most reliable in obtaining chorionic villi. The overall success rate for chorion biopsy was 73% in the first 100 patients studied.

Biopsy↗
PubMed1985

Conservative treatment of liver hematoma in the postpartum period. A report of two cases.

Two pregnant women at term had antenatal symptoms of impending preeclampsia (thrombocytopenia, liver dysfunction) and developed clinical signs of a leaking subcapsular liver hematoma in the immediate postpartum period. They were managed conservatively, with blood transfusions and ultrasonic computerized tomographic monitoring of the hematoma. Both did well, and their hospital stays were brief. These cases suggest that immediate celiotomy may not always be necessary for suspected liver hematoma associated with preeclampsia.

Adult↗
PubMed1985

Pruritus and hyperplacentosis.

Hyperplacentosis refers to the maternal manifestations of increased placental activity, such as elevated human chorionic gonadotropin, theca luteal cysts, preeclampsia, and/or pruritus. Six cases of apparent hyperplacentosis were diagnosed in the third trimester because of maternal complaints of pruritus. The association of maternal or fetal complications with hyperplacentosis is described.

Adult↗
PubMed1985

Artifacts and pitfalls of high-resolution CT scans.

Artifacts on CT images have been observed since the introduction of CT scanners. Some artifacts have been corrected with the improvement of technology and better understanding of the image formation and reconstruction algorithms. Some artifacts, however, are still observable in state-of-the-art high-resolution scans. Many investigations on CT artifacts have been reported. Some artifacts are obvious and some are similar to patterns commonly associated with pathological conditions. The present report summarizes some of the causes of artifacts and presents some artifacts that mimic pathology on clinical scans of the head and spine. It is the intention of this report to bring these artifacts and potential pitfalls to the attention of the radiologists so that misinterpretation can be avoided.

Brain Diseases↗
PubMed1984

Assessment in the mouse of cefoperazone as a treatment for mastitis.

The value of cefoperazone in mastitis therapy was assessed in the mouse model of mastitis primarily by its effect on bacterial cell numbers in the gland. In addition histological studies showed that the drug was not an irritant in the mammary gland. Pharmacokinetic studies showed that it was slowly absorbed from the gland (six days to absorb 500 micrograms) but was easily removed by milking. In ascending order of efficacy cefoperazone (500 micrograms/gland) was active against four-hour-old intramammary infections caused by Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Streptococcus agalactiae and Strep uberis. The effect against Staph aureus was titrated down to a dose of 50 micrograms/gland. Cefoperazone was not bactericidal against intracellular staphylococci but it did sensitise them to the action of lytic enzyme. Cefoperazone and cloxacillin behaved similarly against progressive staphylococcal mastitis. Both antibiotics significantly reduced the bacterial numbers when four-hour-old infections were treated but the effect on 26-hour-old infections was perceptible only when each antibiotic was assayed against saline treatment in the mouse. The results suggest that further studies in dairy cattle should be undertaken.

Animals↗
PubMed1984

Levamisole and bovine mastitis.

Levamisole is an anthelmintic drug which also has immunomodulatory properties. The application of these immunomodulatory properties in the prevention and, or, treatment of bovine mastitis is considered. In the light of the available evidence on the use of levamisole against mastitis and of our understanding of the pathogenesis of mastitis it is thought that the prospect of using levamisole beneficially is limited. However, drying-off and parturition are two times at which levamisole may have rational application in mastitis prevention.

Animals↗
PubMed1984

Distribution in caesium chloride gradients of proteoglycans secreted by bovine aorta smooth muscle cells and study of their aggregation with hyaluronate and cartilage proteoglycan.

Smooth muscle cells from media of bovine aorta were cultured with [35S] sulphate and [3H]glucosamine. The 4 M guanidinium chloride extract of cell layer had a greater proportion of its glycosaminoglycans as hyaluronic acid, heparan sulphate and dermatan sulphate than did medium, which contained relatively more chondroitin sulphate. Fractionation of medium and cell layer extract by caesium chloride density gradient centrifugation, under associative and dissociative conditions, respectively, established that heparan sulphate and dermatan sulphate proteoglycans had lower buoyant densities than chondroitin sulphate proteoglycans. Chromatography on Sepharose CL2B showed that chondroitin sulphate-rich proteoglycan from medium bottom fraction contained no high molecular weight aggregate but underwent partial reaggregation with hyaluronic acid. A slight shift to higher molecular weight occurred if cartilage proteoglycan monomer was added to medium bottom fraction, but if both hyaluronic acid and cartilage proteoglycan monomer were added, a high degree of aggregation took place. These observations could be explained if medium bottom fraction contained a proteoglycan-deficient aggregate with a low molecular weight hyaluronate species. Bottom fraction from cell layer extract showed none of these properties.

Animals↗
PubMed1984

Recruitment of neutrophils by an encapsulated coagulase-negative strain of Staphylococcus simulans in the mammary gland of the mouse.

The encapsulated coagulase-negative strain of Staphylococcus simulans (strain 76) was inoculated into the mammary glands of lactating mice. In contrast to the coagulase-positive encapsulated Staphylococcus aureus (strain M), which elicited a neutrophil response within 18 hr, strain 76 organisms multiplied in the glands but failed to elicit a neutrophil response for 3 days; they were then eliminated from the gland by 8 days. When strain 76 was inoculated into mice whose offspring had been removed 3 days earlier, a neutrophil response was induced within 18 hr and, although phagocytic ingestion was resisted for at least 42 hr, the organisms were eliminated from most glands within 5 days. Inoculation of a naturally occurring double-stranded RNA (BRL 5907) into the mammary gland induced a macrophage infiltration of the alveolar lumen that was qualitatively similar to 3 days involution. Intramammary inoculation of strain 76 18 hr after BRL 5907 resulted in a neutrophil infiltration within 6 hr. In vitro, strain 76 stimulated the release of chemotactic factors for neutrophils from bovine mammary gland macrophages. The results suggest that the recruitment of neutrophils by strain 76 in the mammary gland of the mouse is mediated by macrophages.

Animals↗
PubMed1984

Phagocytosis of Staphylococcus aureus by bovine mammary gland macrophages and intracellular protection from antibiotic action in vitro and in vivo.

Macrophages isolated from the involuted bovine mammary gland were cultured in vitro. Phagocytosis of opsonized Staphylococcus aureus occurred rapidly, but intracellular killing of bacteria was slow. Many intracellular staphylococci survived for up to 4 d exposure to extracellular cloxacillin and emerged from within the macrophages to multiply extracellularly when the antibiotic was inactivated. Rifampicin was significantly more efficient than cloxacillin in killing intracellular S. aureus after 18 h incubation, but it too failed to sterilize the cultures within 3 d. Staphylococci, which had remained viable within macrophages during 20 h incubation with extracellular cloxacillin, showed an increased sensitivity to dilute lysostaphin on subsequent exposure. A 3 d course of intramammary therapy with cloxacillin, commencing simultaneously with an infecting inoculum of approximately 10(8) colony forming units (c.f.u.) S. aureus, apparently eliminated the infection from one quarter of the udders of each of three lactating cows, but bacteria were re-isolated from two cows after a delay of several days. However, when other quarters of the same cows were infected with approximately 10(8) c.f.u. S. aureus which had been phagocytosed by autologous mammary macrophages, similar simultaneous antibiotic therapy failed to affect these infections. The in vitro and in vivo findings indicate the significance of intracellular survival of S. aureus as a factor contributing to failure of antibiotic therapy.

Animals↗