Biomedical subjects
Publications and source records attributed to M C Robson.
This case of successfully managed clinical tetanus following osteomyelitis of a minimally fractured zygoma serves to remind us to consider the possibility of this diagnosis even in an apparently uncomplicated facial wound. The prodromal and clinical signs of tetanus in this case are classical. Early recognition of the disease and appropriate supportive measures lead to an anticipated outcome.
Although edema is evident immediately after a burn, the diffusion of nutrient chemical constituents of the body is not impaired. Blister fluid, not unlike plasma or serum, contained all substances found in the body, including parenterally administered penicillin. The elevation of potassium and the cation to anion imbalance is primarily due to the Na/K cellular pump malfunction, and the destruction of the permeability of the cell membrane is most likely a direct result of complement and other cellular enzymes, which include the prostaglandins and thromboxanes. The elevated SGOT, CPK, and LDH indicated severe trauma to the cells in the immediate area of burn and possibly to the skeletal muscle. The presence of immunoglobulins indicated that high-molecular-weight proteins diffuse equally well during this edematous phase (IgM, 900,000; IgG, 190,000). Evidence of this nature strongly suggests that the integrity of the burn blister by maintained.
A model for the quantitative study of bacterial levels in blood, ascitic fluid, and liver, induced by Escherichia coli in the rat, has been devised. Three experimental situations were then studied: non-fatal peritonitis, fatal peritonitis induced by bacteria rendered more virulent by serial passage through test animals, and fatal peritonitis using haemoglobin adjuvant with the more virulent strain. Results indicate that a variety of defense mechanisms are operant in the host animal. In the non-fatal peritonitis, clearance of free bacteria from the peritoneum is observed with a late rebound in local and systemic populations. These phenomena correlate well with in vitro studies of bacterial uptake by peritoneal macrophages. In fatal peritonitis without adjuvant, much larger numbers of bacteria seem to escape initial clearance in the peritoneum and proximal reticuloendothelial system with resultant overwhelming septicaemia. In fatal peritonitis with adjuvant, much less clearance of organisms from the peritoneum is observed, with resultant overgrowth of bacteria and host death. It thus seems that the initial host defenses center around peritoneal clearance of introduced organisms, and that processes which interfere with this clearance prove fatal.
Selective thromboxane inhibitors were evaluated as a pharmacological agent in the prevention of progressive dermal ischemia after burning. Standardized partial-thickness burns were inflicted on guinea pigs. Burned guinea pigs were separated into four groups: one served as a control, one was treated with Imidazole, one with dipyridamole, and the other with methimazole. Histology and depth of dermal perfusion were evaluated by the India ink perfusion technique. Untreated controls showed progressive dermal ischemia with complete absence of India ink-filled vessels in the dermis by 24 hours. Imidazole, dipyridamole, and methimazole improved dermal perfusion as suggested by relative levels of India Ink filling. Preservation of dermal appendages was seen secondarily to improved dermal microcirculation with an eight-fold increase in hair follicles in treated guinea pigs compared with controls. This study suggest that thromboxane plays a role in progressive dermal ischemia. Selective inhibition of thromboxane avoids the side effects associated with complete suppression of the metabolism of arachidonic acid.
Accidental hypothermia, a core temperature below 34 degrees C., is frequently fatal, particularly in the ill and elderly. Traditional treatment methods result in reported mortalities of between 45 and 100 per cent. Despite these terrible statistics, advocates of slow rewarming persist. They cite the shock and vascular collapse which can occur with peripheral dilation as reasons to avoid rapid external rewarming. Isolated successes using internal core rewarming, such as hemodialysis or cardiopulmonary bypass, are spectacular but not practical in the usual clinical situation. By combining methods used for the resuscitation of burn injury with the treatment principles for frostbite, a highly effective treatment protocol results. Agressive fluid resuscitation, rapid immersion rewarming and careful systematic monitoring have been used to treat ten consecutive patients without a single death. Concomitant problems of alcoholism, stroke, myxedema, tuberculosis and paraplegia were also treated. Rapid external rewarming by immersion can result in a low mortality in patients with severe hypothermia.
Fresh homogenized mammary gland adenocarcinoma (C3HBA) material was subcutaneously inoculated in the anterior right thigh of transplant host mice (C3H/HeJ). When tumors were palpable, the mice were separated into three groups. The test group received biweekly intratumoral injections of Mycobacterium ulcerans filtrate containing 40 mg of protein per ml. One control group received intratumoral injections of normal physiological saline, and the remaining group received no treatment at all. The survival rate of toxin-treated animals was 13.5% at 15 weeks when compared with the control groups. Additionally, tumor metastasis was apparently abrogated in test animals when compared to the control animals. Marked necrosis of the tumors in the test animals was noted by histological examination. Controls showed slight to moderate degrees of tumor necrosis. In this model Mycobacterium ulcerans toxin appears to have therapeutic value as an antitumor agent.
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Dextranomer beads, a new treatment for leg ulcerations, has been widely promoted. Comparison with simple saline dressings in an animal model demonstrated no significant difference in its ability to decrease the quantitative bacterial count of granulation tissue. In a prospective randomized clinical study it appeared that, in moist exudative venous stasis ulcers, dextranomer beads may be an effective way of decreasing bacterial contamination. In drier ulcerations caused by this ischemia, this difference was not observed. Recognized principles of treatment such as elevation, debridement, physiological protection of granulation tissue, or vascular reconstruction are as important as a particular dressing regimen and must be utilized in the treatment of leg ulcerations.
This report describes 2 cases of familial myasthenia gravis presenting as velopharyngeal incompetence. The diagnosis was made only after pharyngoplasty had been done. Symptoms suggesting possible myasthenia gravis are seen in speech therapy and cleft palate clinics, and often labeled "palatal insufficiency" without a more specific diagnosis. In spite of the fact that myasthenia gravis is usually mentioned in the differential diagnosis of velopharyngeal incompetence, it is rarely ruled out by specific studies. We urge that myasthenia gravis be ruled out by definitive tests when the cause of neuromuscular dysfunction cannot be definitely established.
The mesenteric microvasculature was observed before and after a distant full-thickness cutaneous burn in rats. Diameters, flow velocities, and white blood cell sticking and emigration were measured. Between 30 and 360 minutes postburn 13 to 16 WBC's were found to stick to the venular walls which had an area of 1.57 x 10(4) microns(2). Therefore, the number of WBC's emigrating from the vascular compartment during the 6-hour observation period could be as many as 0.51 X 10(9)/kg. Based on known values for total stores of WBC's, the data suggest that granulocyte sticking and emigration could account for a consumption of granulocytes that on an acute basis could deplete the body stores, which could explain the apparent decrease in total body granulocytes seen clinically following major thermal trauma.
A new access incision for the extirpation of intraoral malignancies has been used in 16 cases, and it is described--together with its apparent advantages.
A rapid slide technique to provide quantitative bacteriologic assessment of wounds in elderly and debilitated patients is described. It involves the use of material from dextranomer-bead (Debrisan) wound dressings to replace tissue biopsy for deciding when a wound is ready for closure or when a specific therapy is no longer efficacious. In 27 patients an 81 percent correlation was demonstrated between the bacterial count as determined by the new method and that determined by the more complicated tissue biopsy.
It has been suggested that deep partial-thickness burns of the hand which remain unhealed by 14 days should be excised and totally resurfaced. Controlled data supporting this suggestion is not available. Therefore, a prospective randomized study was performed on 222 burns of the hand to evaluate if excision and skin grafting had any advantage over conservative management. Full-thickness burns were eliminated from the series by excision and grafting them as soon as possible after the diagnosis had been made. To eliminate the very superficial burns, randomization did not take place until the wound had remained unhealed for ten days and would not heal for at least another week. In the two groups, the first ten days were managed similarly with topical antibacterials, escharotomies when necessary, and splinting in the "safe" position. Conservatively managed hands were treated with scarlet red gauze dressing as soon as all eschar had been removed. Those cases randomized into the excision and grafting group were operated upon approximately day 14. Physical therapy was the same in both groups except for the immediate period after grafting. Results were recorded by active and passive joint measurements and photographs on predetermined days throughout the study. In this study, spontaneous healing, taking as much as five weeks, gave acceptable results, comparable to excision and grafting performed at two weeks. The use of range of motion exercises, accurate splinting and pressure allowed optimal healing and prevented stiffness and contractures in both groups. There was no significant difference between the two treatment modalities.
Infection in the surgical patient, like infection elsewhere in the body, is a manifestation of a disturbed host-bacteria equilibrium in favor of the bacteria. It results when bacteria indigenous to that patient achieve dominance over the factors of host resistance. This is reflected by a quantitative increase in the bacterial presence. To be able rationally to prevent and manage such infection requires understanding of how each prophylactic or therapeutic maneuver will work to reestablish the normal equilibrium in the specific situation in which the surgeon finds his patient.
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The goal in the treatment of septic burn wounds, as in any infection, is to reestablish the normal balance between the bacteria and the host defense. This is readily done by controlling the numerical level of bacteria while expending all efforts to remove irreversibly damaged tissue and obtaining a closed wound by autograft with the patient's own skin as rapidly as possible.
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