Biomedical subjects

D A Marshall

Publications and source records attributed to D A Marshall.

31 records · Page 2Linked to original sources

PubMed1989

Infective endocarditis caused by Streptococcus agalactiae.

We report a series of five cases of infective endocarditis caused by Streptococcus agalactiae (group B streptococcus) in Glasgow over a 30 month period. There were three males and two females mean age 48.6 years (range 28-63 years). Only one patient had previous valvular heart disease. The infections were characterised by an acute presentation and an aggressive course with major arterial emboli. Despite early diagnosis and appropriate intravenous antibiotics three patients died, one after valve replacement and two before surgery could be undertaken. The remaining two patients had successful valve surgery and have recovered. S. agalactiae endocarditis is an uncommon but important condition which carries a high mortality. The infection is difficult to control with antibiotics alone and therefore early surgery may be indicated.

Adult↗

PubMed1989

Topical mupirocin treatment of impetigo is equal to oral erythromycin therapy.

Topical antimicrobial therapy has not been effective in the past against cutaneous bacterial infections. In this study, a new topical antibiotic ointment, mupirocin, was compared with oral erythromycin ethylsuccinate in the treatment of impetigo. Seventy-five patients clinically diagnosed as having impetigo and with positive cultures of Staphylococcus aureus, Streptococcus pyogenes, or both were examined in an investigator-blinded study. Patients used topical mupirocin applied three times daily or the usual oral dose of erythromycin ethylsuccinate (30 to 50 mg/kg per day). Patients' lesions were examined clinically and cultured bacteriologically on days 0, 3, and 8, and 1 week after treatment. Susceptibility testing was performed on pathogens isolated to determine antibiotic resistance. Mupirocin treatment produced similar clinical results to oral erythromycin and was superior in the eradication of S aureus, including antibiotic-resistant S aureus. These results show topical mupirocin to be a safe and effective alternative to oral antibiotic therapy in the treatment of impetigo.

Administration, Oral↗

PubMed1987

Model for studying bacterial adherence to skin wounds.

The adherence of bacterial pathogens to wounded skin is probably the first step in wound infection. This report describes the development of a bioassay to simulate the adherence of bacteria to wounds. The adherence of bacteria was examined by exposing wounds to known quantities of pathogens, washing the wounds with distilled water, and quantitating the number of adherent bacteria per cm2 of tissue. Our studies focused on the effects of naturally occurring mediators of bacterial adherence, such as wound fluid, serum, and fibronectin. Bacterial adherence was shown to be challenge dependent. Addition of wound fluid, serum, and heat-inactivated serum was shown to reduce the adherence of Pseudomonas aeruginosa to the wound surface compared with that of a saline control. Additional fibronectin treatment of the wound had no effect on the adherence of Staphylococcus aureus. The ability to identify what affects the binding of bacteria to wounded skin can lead to a better understanding of wound infection.

Animals↗

PubMed1986

Masera's organ responds to odorants.

Electroolfactogram (EOG) recordings from the rat septal olfactory organ (SO) provide the first demonstration of its broad-range chemosensitivity, and clearly establish this structure as a functioning component of the mammalian intranasal chemosensory system. SO sensitivity to lower concentrations of at least one common test odorant (pentyl acetate) exceeds that at sites located on the septal portion of the main olfactory neuroepithelium. Signals from the SO, as first proposed, thus could have an alerting function and provide information relevant to odor stimulus assessment.

Animals↗

PubMed1986

Povidone-iodine in polyethylene oxide hydrogel dressing. Effect on multiplication of Staphylococcus aureus in partial-thickness wounds.

We studied the ability of a polyethylene oxide hydrogel dressing (Vigilon) containing povidone-iodine to prevent Staphylococcus aureus proliferation in partial-thickness wounds. We previously reported that a single application of povidone-iodine on wounds challenged with 2 X 10(6) S aureus was not effective in reducing the number of S aureus after 24 hours. It was therefore hypothesized that povidone-iodine might be effective if it was available continuously and applied to wounds containing a smaller number of bacteria. To test this hypothesis, we made multiple partial-thickness wounds (5 X 7 X 0.3 mm) on six domestic pigs. We then inoculated the wounds by scrubbing them with either a low concentration (log 3.5) or a high concentration (log 7) of S aureus suspension. The wounds were either treated with Vigilon or Vigilon containing povidone-iodine or left air exposed. Wounds from each of these treatment groups were cultured by the scrub technique for S aureus with a 0.5% sodium thiosulfate-polysorbate (Tween) 80 solution 5 minutes, 30 minutes, 24 hours, or 48 hours later. A significant reduction in the number of S aureus recovered from wounds treated with Vigilon containing povidone-iodine was seen with the group inoculated with a low bacterial concentration after 24 hours; but no reductions were observed when wounds were inoculated with the higher bacterial concentration of log 7. We found Vigilon containing povidone-iodine to be an effective inhibitor of S aureus in wounds over a 24-hour period when the organism was present in low numbers.

Animals↗

PubMed1985

Rat trigeminal, olfactory and taste responses after capsaicin desensitization.

Experiment 1 showed that capsaicin injections severely reduced or eliminated nasal trigeminal responses to 3 odorants. Experiments 2 and 3 investigated whether desensitized animals could behaviorally detect and discriminate odors. Capsaicin treated animals had no measurable deficits in locating buried food, in odor aversion learning, or in operant odor detection and discrimination. Experiment 4 examined whether behavioral responsiveness to salty, sour and bitter tastes was affected by desensitization. Capsaicin injections did not affect responsiveness to salty or sour, but may have raised rejection thresholds for bitter. Broadly, the present results suggest that substance P-containing fibers mediate trigeminal responsiveness to odorants and irritants but that the loss of this responsiveness does not appreciably affect smell or taste, per se.

Animals↗

PubMed1985

Occlusive wound dressings to prevent bacterial invasion and wound infection.

This study was designed to examine the possibility that some occlusive dressings are barriers to wound penetration by pathogenic bacteria. Two common skin pathogens, the nonmotile, Staphylococcus aureus, and the motile, Pseudomonas aeruginosa, were used to challenge dressings placed on partial-thickness wounds in swine. S. aureus was recovered from 100% of air-exposed wounds (log, 5.5 +/- 1.1) and from 50% of Op-Site-treated and Vigilon-treated wounds (log, 6.1 +/- 1.1). S. aureus was not isolated from DuoDERM-covered wounds. P. aeruginosa was recovered from 100% of air-exposed wounds (log, 5.1 +/- 0.5) and 100% of Op-Site-covered and Vigilon-covered wounds (log, 5.8 +/- 1.8). P. aeruginosa was not recovered from DuoDERM-covered wounds. These studies lend support to the idea that dressings may protect wounds from invasion by pathogenic bacteria and demonstrate the need to evaluate their bacterial barrier properties in situ.

Animals↗

PubMed1985