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Biomedical subjects

J C Anderson

Publications and source records attributed to J C Anderson.

At least 163 records · Page 9Linked to original sources
PubMed1982

Enhanced killing of penicillin-treated S. aureus by host defences: effects of amoxycillin, cloxacillin and nafcillin in vitro and in experimental mastitis.

The effects of pretreatment of Staphylococcus aureus with subMIC or 10 x MIC amoxycillin, cloxacillin and nafcillin on subsequent killing by bovine neutrophils or sensitivity to lysostaphin were examined in vitro, using penicillinase positive and negative strains. All penicillins increased the susceptibility of S. aureus to bovine neutrophils; with amoxycillin this was most marked with the penicillinase negative strain. Cloxacillin pretreatment was significantly more effective than nafcillin or amoxycillin in some tests and equally effective in others. The sensitivity of S. aureus to lysostaphin was increased following cloxacillin or nafcillin exposure. In a mouse model of mastitis, more cloxacillin and nafcillin-treated S. aureus (at 1/4 MIC) were killed than untreated bacteria 1 hr after infection but by 4 hr no differences were found. No differences were seen after intramammary infection with 10 x MIC penicillin-treated S. aureus. In glands with established chronic mastitis both cloxacillin and nafcillin at high doses failed to kill staphylococci. These findings indicate that prior exposure to penicillins increases staphylococcal susceptibility to killing by neutrophils but following phagocytosis, intracellular bacteria are protected from the lethal action of penicillins.

Amoxicillin↗
PubMed1982

Controlled study of treatment for disseminated intravascular coagulation in the neonate.

Thirty-three neonates with disseminated intravascular coagulation were assigned randomly to one of three treatment groups: (1) exchange transfusion, (2) administration of fresh-frozen plasma and platelets, and (3) control (no therapy directed specifically at the coagulopathy). The three groups were comparable for degree of abnormality in initial coagulation studies and underlying pathologic processes. Shock was a common accompaniment of DIC and occurred in 85% of all infants. In all cases, underlying disease states and shock were treated aggressively. Resolution of DIC and survival were not different in the three treatment groups. Outcome of DIC was dependent on the success of treatment of the underlying pathologic process and aggressive supportive care, including restoration of blood pressure, but was not altered by therapy specifically directed at the coagulopathy.

Blood Transfusion↗
PubMed1982

pH-dependent penicillin tolerance may protect intraleukocytic Staphylococcus aureus from killing by cloxacillin.

Exposure of Staphylococcus aureus to cloxacillin at neutral pH rendered the bacteria more susceptible to subsequent lysis by lysostaphin. This sensitization effect also occurred at lower pH levels which were nonpermissive for the bactericidal action of cloxacillin, but the effect disappeared at pH 5.0. These findings elucidate previous observations on the protection of intraleukocytic S. aureus from killing by cloxacillin and indicate that low pH in the phagolysosomes may be involved.

Cloxacillin↗
PubMed1982

The effect of staphylocoagulase in the mammary gland of the mouse.

Purified coagulase from a strain of S. aureus was inoculated into the mammary glands of mice which were examined at 4-hourly intervals over 28 h. Coagulase induced a neutrophil response at 4 h which was sustained throughout the experiment, and was accompanied by hyperplasia of the alveolar epithelium. There was no evidence of intravascular clotting. The response of the gland to coagulase was compared with the response following inoculation of 3 different strains of viable staphylococci.

Animals↗
PubMed1981

Encapsulated, coagulase-negative strain of Staphylococcus simulans.

An encapsulated strain of Staphylococcus simulans (strain 76) isolated from a clinical case of bovine mastitis was demonstrated by the India ink technique, using both a light microscope and an electron microscope. The strain failed to kill mice after intraperitoneal inoculation but resisted ingestion by peritoneal phagocytic cells. The behavior of the strain helps to delineate the antiphagocytic role of the capsule.

Animals↗
PubMed1981

A membrane filtration method for estimating the number of viable bacteria in solutions containing antibiotic.

The method involves filtration of dilutions of the mixture through a membrane filter followed by replication on ox blood agar and enumeration of organisms. This method was compared with the conventional drop count method, and a significant correlation was found (r = 0.985). When solutions containing antibiotic were used, the membrane filtration method gave a more reliable estimate of the viable count at the time of sampling.

Animals↗
PubMed1981

Therapy of experimental staphylococcal mastitis in the mouse with cloxacillin and rifampicin, alone and in combination.

Cloxacillin effectively killed Staphylococcus aureus in vitro and in experimental acute mastitis in the mouse, but was ineffective in reducing bacterial counts in those with experimental chronic mastitis. Rifampicin was similarly bactericidal for staphylococci in vitro and in acute mastitis but it also significantly reduced numbers of viable bacteria in chronic mastitis. Exposure of multiplying staphylococci in vitro and in vivo to rifampicin alone led to the emergence of resistant bacteria, but this was prevented by the use of a combination of rifampicin with cloxacillin. This combination showed neither antagonism nor synergy in vitro, was more effective than either antibiotic alone in acute mastitis and killed S aureus in the chronic infection as effectively as rifampicin alone.

Animals↗
PubMed1981

Prevention of umbilical artery catheter clots with heparinized infusates.

49 neonates requiring umbilical artery catheters (UACs) were randomly assigned to receive standard or heparin-containing infusates. 3 of 23 (13%) of the patients receiving heparin had catheters removed because they became functionally occluded compared to 15 of 26 (58%) in the control group (p less than 0.005). 4 of 13 (31%) single injection aortograms obtained in control infants demonstrated thrombi, compared to none of 7 in the heparin group. 1 patient in the heparin group had an aortic clot demonstrated at post-mortum examination. There were neither clinical coagulopathies nor abnormalities of partial thromboplastin time attributable to the administration of heparinized fluids. Heparinization of UAC infusates appears to be a safe method of reducing the risk of catheter occlusion. Heparin effect on large vessel clot risk remains unproven.

Blood Coagulation Disorders↗
PubMed1980

Diagnosis and treatment of fluid-filled renal structures in children with ultrasonography and percutaneous puncture.

The application of ultrasonographic and percutaneous needle puncture techniques in the diagnosis of various fluid-filled renal anomalies has permitted rapid delineation of anatomic detail, more definitive physiologic evaluation, and drainage, when necessary, in a safe and cost-effective manner. Its usefulness in children is emphasized in 6 illustrated cases of male infants with minimally or nonopacified renal anomalies, one of the more difficult diagnostic problems in pediatric urology.

Adolescent↗
PubMed1980

The effects of cloxacillin on staphylococci phagocytosed by bovine neutrophils.

The effects of cloxacillin on staphylococci within neutrophils from the peripheral blood of cattle were examined. When cloxacillin was added to a preparation of intracellular staphylococci suspended in nutrient broth at 37 degrees C in the presence of lysostaphin, significantly more staphylococci were killed than in the controls without the antibiotic. Cloxacillin entered the neutrophils and made the intracellular staphylococci sensitive to lysis by lysostaphin when the neutrophils were disrupted. The intracellular action of cloxacillin was greater than when Hanks' balanced salt solution was the suspending fluid or when the broth was incubated at 4 degrees C. Failure to observe the effect in these circumstances was possibly due to a very low rate of metabolism in the staphylococci.

Animals↗
PubMed1979

Ultrasonography in an early hydatidiform mole.

An early hydatidiform mole containing a fetal sac is shown in grey scale echograms. It is suggested that all hydatidiform moles can be shown to contain a gestation sac if examined early enough.

Adult↗
PubMed1979

"Prune Belly" syndrome.

A large sonolucent mass was first revealed by the ultrasonic echography examination of a fetus at 18 1/2 weeks' gestation, but was no longer present at 28 1/2 weeks' gestation. The fetus was subsequently born with the "prune belly" syndrome. The case is described, and the possible causes, and possibilities of prevention, of "prune belly" are discussed.

Abdominal Muscles↗