Biomedical subjects

M C Robson

Publications and source records attributed to M C Robson.

At least 127 records · Page 7Linked to original sources

PubMed1985

The use of prophylactic antibacterials in plastic surgery: a 1980s update.

A questionnaire designed to determine the pattern of usage of prophylactic antibacterials, similar to one used a decade ago, was distributed to plastic surgeons, of whom 1718 responded. The pattern of antibacterial use in 8 major categories and 55 separate operations and circumstances was reviewed. The timing and the influence of various modifying factors was evaluated. The data present the pattern of antibacterial use by plastic surgeons at this point and time, that is, what is "usual and customary".

Anti-Bacterial Agents↗

PubMed1985

Burns. Prostaglandins and thromboxane.

This article attempts to delineate the role of the prostanoids in thermal injury, based on clinical and experimental trials. It also describes the authors' concept of the cause of progressive dermal ischemia in the thermal injury and possible therapeutic measures to prevent or reduce this detrimental effect.

Animals↗

PubMed1984

Skin testing. A valuable predictor in thermal injury?

Delayed hypersensitivity skin testing, a prognosticator of sepsis in severely injured patients, has been reported to have varied usefulness following thermal trauma. Skin tests were immediately and sequentially performed with six recall skin-test antigens on 69 patients with burns on greater than 25% of their total body surface area (TBSA). Skin tests were also immediately and sequentially performed with the same recall skin-test antigens on 42 patients with less than 25% of TBSA burned, as controls. In addition, calorie intake was recorded for all patients. Of the 69 patients with greater than 25% of TBSA burned, nine were normal, 13 were relatively anergic, and 47 were anergic. Of the patients in the less than 25% group, 13 were normal, 16 were relatively anergic, and 13 were anergic. In evaluating these data, we concluded that totally anergic patients are no more likely to die of sepsis than are normally responsive patients, nor are they more likely to have sepsis than normal and relatively anergic patients.

Adolescent↗

PubMed1984

Acute effects of tobacco smoking on blood flow in the cutaneous micro-circulation.

p6 experimental model has been designed to help study the acute effects of tobacco smoking on the cutaneous micro-circulation. Arterioles in the nude mouse ear are directly visualised by intravital microscopy and the blood flow is quantified. Arteriolar vasoconstriction and decreased blood flow are seen in response to smoking. The implications of post-operative smoking for the patient undergoing flap surgery are discussed.

Animals↗

PubMed1984

The detrimental effect of cigarette smoking on flap survival: an experimental study in the rat.

Cigarette smoking is commonly prohibited after surgery involving flaps. This admonition against smoking has been justified on the theoretical grounds that flap survival could be decreased by the cutaneous vasoconstriction and increased platelet aggregation produced by smoking cigarettes. A smoke chamber was constructed to evaluate directly the effect of intermittent cigarette smoke exposure on the survival of a McFarlane flap on the dorsum of a rat. The O2, CO2 and temperature were monitored in the chamber during smoke exposures and consistently approximated values seen in room air. Average flap survival at 7 days in control rats not exposed to cigarette smoke was 75.2% while flap survival decreased to 40.1% in rats intermittently exposed to cigarette smoke. The difference was statistically significant (p less than 0.01). Changes in carboxyhaemoglobin levels similar to those observed in human smokers were also found in the smoke-exposed rats. These findings support the concept that post-operative cigarette smoking is detrimental to flap survival.

Animals↗

PubMed1984

Prostanoid derivatives in experimental flap delay with formic acid.

The physiological changes that allow increased flap survival after flap delay have never been clearly defined. Inflammation has been postulated as a critical factor in flap delay and prostaglandins are known to be mediators of the inflammatory response. To evaluate the role of prostanoid derivatives in experimental flap delay, 0.2% formic acid was injected under the outline of modified McFarlane flaps in 20 rats and saline was injected under the flap outline in 20 control rats. Two weeks later the flaps were raised on all the rats. Average flap survival one week after flap elevation was 65.5% after formic acid delay and 42.9% after saline delay. Biopsies were taken from the flaps both during the delay period and after flap elevation. The specimens were stained for PGE2, PGF2 alpha and thromboxane. Changes noted in the levels of these prostanoid derivatives suggest that they may indeed mediate flap delay.

Animals↗

PubMed1984

Skin grafting herpetic ulcers.

Recurrent and chronic herpetic skin ulcers are associated with the persistence of virus in the dorsal root ganglia serving the respective dermatomes. Descriptions of surgical approaches to control herpetic skin disease have recently appeared in the medical literature. We report the successful excision and skin grafting of chronic genital ulcers. Our subsequent animal studies support our expectations that potential seeding and reinfection of the grafted skin can occur following graft reinnervation. This problem must be watched for following grafts of herpetic ulcers in humans.

Abdomen↗

PubMed1984

The treatment of ulcers in patients with mycosis fungoides with split-thickness skin grafts.

Five patients have recently been treated at this institution for skin ulcerations caused by mycosis fungoides and its treatment with total body electron beam radiation therapy. Both the disease and its treatment can injure epidermal appendages as well as the blood supply to the skin. As a result of this potential damage, there was initial concern that skin grafts might not take and donor sites might not heal in these patients. Though skin grafting has not been universally successful, we have been able to skin graft the majority of the ulcerated lesions in these patients with good results. Donor sites have healed, though more slowly than usual. Skin grafting can be effective for treating ulcers in patients who have undergone total body electron beam radiation therapy for mycosis fungoides.

Adult↗

PubMed1984

Effect of intraarterial prostacyclin on survival of skin flaps in the pig: biphasic response.

Previous research has implicated arachidonic acid metabolites in the failure of the distal dying flap. The progressive ischemic necrosis has been postulated to be secondary to excessive thromboxane A2 production, which upsets the normal balance between prostacyclin and thromboxane. We have examined the effect of continuous intraarterial prostacyclin infusion on axial skin flap survival in the pig, in an effort to reestablish homeostasis. We found prostacyclin to have a biphasic effect upon the flap survival. Low-dose locally administered prostacyclin was of benefit in flap salvage; however, the complicated pharmacological effect of the agent is emphasized.

Animals↗

PubMed1984

Acceleration of capsule formation around silicone implants by infection in a guinea pig model.

Fibrous capsules surrounding silicone implants were investigated in a new guinea pig model to delineate some of the factors leading to capsular contracture. Both the implant surfaces and tissue capsules were examined by light and scanning transmission electron microscopy (STEM + SEM) with x-ray energy spectroscopy (XES). The capsular tissues were qualitatively similar to those recovered clinically, showing dense parallel collagen deposits, fibroblasts, myofibroblasts, macrophages, and foreign-body giant cells. Silicone was positively identified within intercellular vacuoles and the rough endoplasmic reticulum of macrophages by XES. Tissue recovered from the capsules that surrounded implants that were contaminated with S. aureus presented a qualitatively similar histologic spectrum. The contaminated specimens did show an accelerated response. SEM showed a cellular invasion of the silicone envelopes. We conclude that the model accurately simulates the clinical situation and suggests that immune mechanisms may play a key role in capsular contracture.

Animals↗

PubMed1984

A new explanation for the progressive tissue loss in electrical injuries.

A reproducible electrical injury to the hind limb was produced in rats, an injury characterized by progressive tissue necrosis. Serial histochemical examinations of cross sections with a peroxidase-antiperoxidase method revealed increased production of arachidonic acid metabolites, especially thromboxane, at distal sites near the entrance wound and in periosseous tissues more proximally. Levels of these vasoactive substances remained elevated during the time of progressive necrosis and demarcation of seemingly normal, uninjured tissue. Treatment with agents capable of blocking thromboxane production allowed tissue salvage, as evidenced by a decreased autoamputation rate and an increased total surviving length. From this study it appears that an electrical injury is thermal trauma, producing elevated levels of arachidonic acid metabolites in areas of greatest heat production. Prolonged thromboxane excess, with resultant vasoconstriction and thrombosis in the microcirculation, is seen to play a key role in the progressive tissue loss characteristic of the injury. The use of antithromboxane agents may be of benefit in halting this progression and salvaging tissue in these devastating injuries.

Animals↗

PubMed1983

Acute management of foreign body injuries of the hand.

A review of the identification of foreign body hand injuries is presented with criteria for removal of a foreign body in the emergency department. Indications for acute surgical intervention are presented, and expectant management is discussed.

Emergencies↗

PubMed1983

Cefamandole therapy in hand infections.

Hand lacerations, especially when inadequately treated, may result in infections caused by aerobic or anaerobic bacteria. Anaerobic infections most commonly result from human bite injuries in which there is contact between hand and mouth. The search continues for an ideal antibiotic to employ when anaerobic organisms are suspected. In this study cefamandole, a new cephalosporin antibiotic, was employed whenever anaerobic hand infections were suspected following trauma. In each patient quantitative cultures for both aerobic and anaerobic organisms were obtained. All organisms isolated were tested by standard susceptibility assays for both aerobes and anaerobes. In the case of anaerobes, minimum inhibitory concentration assays were also performed. After the initial culture was obtained, each patient received approximately 1.5 gm of cefamandole every 6 hours for a period of 5 days. This therapy was changed only if susceptibility studies indicated resistance to cefamandole. In our patients, 58% of the infectious organisms were aerobic and facultative anaerobic and 42% were obligate anaerobes. The predominant organisms isolated were Staphylococcus aureus and Peptostreptococcus anaerobius, which accounted for 42% of the infections. In most of the aerobic infections a single organism was isolated, whereas multiple organisms were identified in the anaerobic infections. All but one of the infections responded to cefamandole; the one that didn't was caused by Enterobacter cloacae and required treatment with an aminoglycoside. Because of its broad-spectrum coverage, which includes both aerobes and anaerobes, cefamandole is useful in treating infections, especially those resulting from human bites.

Adolescent↗

PubMed1983

Biocompatibility of silicone implants.

Polydimethylsiloxane has been considered immunologically inert, and previous work seems to have established that the production of circulating antibodies does not occur in response to its implantation. We have investigated the possibility of a cellular immune response to implanted silicone. We have observed histologically that the cellular response to polydimethylsiloxane in sensitized guinea pigs is consistent with a cellular immune reaction. Further studies with EM and XES have demonstrated intracellular silicon in the Golgi apparatus, rough endoplasmic reticulum, and at both ends of cytoplasmic bridges between macrophages and lymphocytes. All of these findings fit with the hypothesis that the cells are processing a silicon-containing complex as an antigen. Finally, macrophage migration inhibition studies have shown evidence of a cellular immune phenomenon. Further studies are planned to characterize the nature of the sensitizing complex and to attempt to confirm the migration inhibition studies in vivo.

Animals↗

PubMed1983

The effect of 5% mafenide acetate solution on bacterial control in infected rat burns.

Mafenide acetate is commonly available as a 10% cream and has been shown to be effective in the prevention and control of burn wound sepsis. The high osmolarity of the cream has been implicated in the pain upon application and the neoeschar formation often seen with its use. Mafenide acetate as a 5% solution has a lower osmolarity, and clinical trials with this agent have shown it to be both well accepted by patients and effective in wound preparation. Information concerning its antibacterial efficacy in comparison with other agents, however, has been lacking. Utilizing the Walker burn model, we have found the 5% mafenide acetate solution used as gauze soaks to be equal to mafenide acetate cream and better than silver sulfadiazine in attaining bacterial control of this experimental burn wound in the rat. The 5% solution provided prompt decrease in bacterial counts to less than 10(5) bacteria per gram of tissue in a majority of wounds by 48 hours of treatment. In addition, such wounds showed no evidence of neoeschar formation. In light of the efficient bacterial control and rapid preparation of the wound for grafting seen in this model, more extensive clinical use of the 5% mafenide acetate solution appears justified.

Animals↗

PubMed1983

Dysplastic nevus syndrome (B-K mole syndrome).

Six cases of dysplastic nevus syndrome were diagnosed at this institution. Two cases of the familial form of the dysplastic nevus syndrome (B-K mole syndrome) are discussed in detail to demonstrate the clinical pattern and variance of the genetic expressivity. The reader is also alerted to the possibility of a melanoma occurring in a clinically nonaffected offspring, as a de novo melanoma. Recommendation for comparative photographic documentation and possibly improved means of treatment are discussed.

Dermabrasion↗

PubMed1983

Analysis of the surface morphology of recovered silicone mammary prostheses.

The surfaces of 11 silicone mammary prostheses were examined by scanning electron microscopy (SEM) and energy dispersive x-ray spectrography (XES). Three of the prostheses were recovered from clinical cases and eight from guinea pig models. The surfaces of the prostheses were covered with an investing film and by 2- to 5-microns spheres aggregated in 40- to 200-microns-wide patches. The embeddedded spheres were blebbed and surrounded by pits. X-ray energy spectrography showed high levels of sodium, chlorine, and potassium. It is concluded from this evidence that phagocytic cells embed themselves within the envelope, perhaps by an immune-mediated phagocytic process.

Animals↗

PubMed1983

Frostbite injuries: a rational approach based on the pathophysiology.

The breakdown products of arachidonic acid have been implicated as mediators of progressive dermal ischemia in both cold and thermal injuries. Increased tissue survival can be demonstrated experimentally with the preservation of the dermal microcirculation by using antiprostaglandin agents and thromboxane inhibitors. Thirty-eight consecutive patients (28 males and 10 females aged 2 mo to 46 yr) with frostbite injuries were treated at the University of Chicago's Burn Center in January 1982 with a protocol designed to decrease the production of thromboxane locally and prostaglandins systemically. All patients recovered without significant tissue loss. The average hospital stay was 5.6 days for acute injuries and 6.9 days for subacute injuries.

Adolescent↗