Treatment of the exposed knee prosthesis

Ten knees with early tissue breakdown after knee arthroplasty resulting in exposed prostheses were treated with different plastic surgical techniques. Six knees were successfully covered: four using a gastrocnemius musculocutaneous flap, one using a fasciocutaneous flap, and one using split-skin grafts. Four knees failed: two using local skin flaps and two using split-skin grafts. A gastrocnemius musculocutaneous flap seems to provide a reliable coverage of the exposed knee joint.     

Terminal complement complexes and anaphylatoxins in septic and ischemic patients

Terminal complement complex (TCC) and anaphylatoxin formation in 18 patients with sepsis and 20 patients with acute limb ischemia were studied before the start of treatment and seven days later. The septic or ischemic patients had elevated levels of plasma TCC before start of therapy. In successfully treated patients these concentrations were within the normal range one week later. Similarly, the plasma anaphylatoxin level was increased before therapy and returned to the normal range within seven days. Escherichia coli incubated in vitro in fresh human serum at body temperature started formation of TCC in a dose-related manner. As complement will induce cellular lysis via TCC and edema via anaphylatoxins, anemia and impaired respiration in these patients may be influenced by increased concentrations of terminal complement complexes and of C3a and C5a.     

Gaseous homeostasis during low-flow anaesthesia

The object of this clinical study was to investigate the circle system gas homeostasis during low-flow anaesthesia using a technique designed to keep a constant inspired oxygen fraction of 0.30. Denitrogenation was adequately accomplished with mask preoxygenation, 10 l/min, for 1 min and an initial fresh gas flow of 5 l/min for 6 min after intubation. There was no need to wash out accumulated nitrogen at intervals, since the already low nitrogen concentration in the system tended to decrease after 1 h. The fresh gas flow of nitrous oxide to oxygen ratio and the inspiratory to end-expiratory oxygen concentration difference both reflected the uptake of nitrous oxide. The calculated rates of uptake of nitrous oxide, a subject of controversy, were in accordance with those found by Severinghaus and Barton & Nunn.     

Hematogenous infection after knee arthroplasty

Twenty-five hematogenously infected knee arthroplasties in 20 patients (17 with rheumatoid arthritis and 3 with arthrosis) were followed for 3 years. Staphylococcus aureus was the major infecting organism. Three patients with four arthroplasties died of sepsis. Two patients had removal of the arthroplasty, one of which resulted in an above-the-knee amputation. Four out of five arthrodeses fused. Two knees healed after early debridement and two healed without surgery. Ten knees had successful revision arthroplasty.

Rheumatoid arthritis and constrained prostheses increase the risk of hematogenous infection. Any infection and especially cutaneous lesions in a patient with a knee arthroplasty should be treated vigorously.     

Leukocyte activation by isolated hyperthermic liver and limb perfusion due to malignancy

Fourteen patients with liver tumor malignancy and sixteen patients with malignant melanoma localized to one limb were studied regarding leukocyte activation with the release of polymorphonuclear neutrophilic (PMN) elastase and of neopterin and formation of cytokines (TNF- and Il-6) during the surgical treatment. Patients undergoing liver resection (n=10), abdominal hysterectomy (n=10), or hip replacement surgery (n=10) served as control groups. Isolated hyperthermic liver perfusion was performed with cytostatic-containing perfusate (melphalan and cisplatinum). Patients with recurrent malignant melanoma confined to one limb underwent isolated hyperthermic limb perfusion with cytostatic-containing perfusate (melphalan). Blood samples for determination of PMN elastase, neopterin, TNF-, and IL-6 were drawn from the patients preoperatively, 1 minute before the start of the perfusion, 60 and 120 minutes after the start of the perfusion, and 24 hours postoperatively. Samples from the perfusate were drawn 60 minutes after the start of the perfusion. High concentrations of plasma PMN clastase were found both in patients undergoing liver and limb perfusion and in patients undergoing liver resection surgery. Elevated concentrations of Il-6 were found in the patients undergoing liver perfusion and in patients undergoing liver resection. In none of the patients were there increased concentrations of neopterin or TNF-. The perfusate contained high concentrations of PMN elastase, neopterin, and IL-6. This study also demonstrated that major surgery leads to elevated concentrations of PMN elastase and IL-6. An increase of PMN elastase and IL-6 was seen in response to perfusion and to surgical trauma.

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Resumen Catorce pacientes con tumores malignos del hígado y 16 pacientes con melanoma maligno localizado en una extremidad fueron estudiados en relación con la activación de leucocitos con liberación de elastasa de PMN y de neopterina y la formación de citocinas (FNT- e IL-6) en el curso del tratamiento quirúrgico. Pacientes sometidos a resección del hígado (n=10), histerectomía abdominal (n=10) y reemplazo de cadera (n=10) sirvieron como grupos control. Se realizó perfusión hipertérmica aislada del hígado con perfusato citostácico (melfalán y cisplatino). Los pacientes con melanoma maligno recurrente confinado a una extremidad fueron sometidos a perfusión hipertérmica aislada de la extremidad con perfusato citostácico (melfalán). Se tomaron muestras de sangre para determinación preoperatoria de elastasa de PMN, neopterina, FNT- e IL-6, un minuto antes de comenzar la perfusión, 60 y 120 minutos después del comienzo de la perfusión y 24 horas después de la operación. Se tomaron muestras del perfusato a los 60 minutos luego del comienzo de la perfusión. Se encontraron altas concentraciones de elastasa de PMN tanto en los pacientes sometidos a perfusión hepática o de la extremidad, como en los pacientes sometidos a resección hepática. Se encontraron concentraciones elevadas de IL-6 en los pacientes sometidos a perfusión hepática y en los pacientes sometidos a resección del hígado. En ningún paciente se encontraron concentraciones aumentadas de neopterina o de FNT-. El perfusato contenía altas concentraciones de elastasa de PMN, neopterina e IL-6. Se encontró un aumento en la elastasa de PMN y en la IL-6 en respuesta a la perfusión y al trauma quirúrgico.

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Résumé Quatorze patients ayant une tumeur maligne du foie et 16 patients ayant un mélanome malin localisé à une extrémité ont été étudiés en ce qui concerne l'activation des leucocytes associée à un relargage d'élastase PMN et de néoptérine ainsi que la formation de cytokinines (TNF- et IL-6) pendant le traitement chirurgical. Trente patients avant eu soit une résection hépatique (n=10), soit une hystérectomie abdominale (n=10) ou une prothèse de hanche (n=10) ont servi de témoins. On a perfusé le foie avec un perfusât de cytostatiques (mélphalane et cis-platine). Les patients ayant un mélanome malin d'une extrémité ont eu une perfusion isolée hyperthermique avec une perfusion de cytostatique (mélphanane). Des échantillons du sang ont été retirés pour déterminer les taux d'élastase PMN, de la néoptérine, du TNF-, et de l'IL-6 en préopératoire, une minute avant le début de la perfusion, 60 et 120 minutes après le début de la perfusion, et 24 heures postopératoirement. Des échantillons ont été retirés 60 minutes après le début de la perfusion. Des concentration élevées d'élastase PMN ont été retrouvées à la fois chez les patients ayant une perfusion hépatique et de l'extrémité et chez les patients ayant eu une résection du foie. Des concentration élevées en IL-6 ont été retrouvées chez le patient ayant une perfusion du foie et chez le patient ayant une résection hépatique. Les concentrations en néoptérine et en TNF- n'étaient pas élevées. Le liquide de perfusion contenait des concentrations élevées en élastase PMN, néoptérine et en IL-6. Cette étude démontre aussi que la chirurgie majeure est associée avec des concentrations élevées en PMN elastase et IL-6. Une augmentation en PMN-élastase et en IL-6 a été retrouvée en réponse à la perfusion et au traumatisme chirurgical.

     

Relation of quantitative coronary lesion measurements to the development of exercise-induced ischemia assessed by exercise echocardiography

To assess the relation of quantitative measures of coronary stenoses to the development of exercise-induced regional wall motion abnormalities, 34 patients with isolated, single vessel coronary artery lesions and normal wall motion at rest underwent exercise echocardiography and quantitative angiography on the same day. Although all 11 patients with a visually estimated stenosis greater than or equal to 75% had an ischemic response and 10 (91%) of 11 patients with a less than or equal to 25% visually estimated stenosis had a normal response by exercise echocardiography, among 12 patients with a visually estimated stenosis of 50%, 6 (50%) had an ischemic response and 6 (50%) had a normal exercise echocardiogram. Quantitative measurements of stenosis severity distinguished patients with ischemic (group 1) from normal (group 2) exercise echocardiographic responses as follows: minimal luminal diameter (mm), group 1 1.0 +/- 0.4 versus group 2 1.7 +/- 0.4, p less than 0.0001; minimal cross-sectional area (mm2), group 1 0.9 +/- 0.6 versus group 2 2.5 +/- 1.1, p less than 0.0001; percent diameter stenosis, group 1 68.3 +/- 14.2 versus group 2 42.2 +/- 12.1, p less than 0.0001; and percent area stenosis, group 1 87.5 +/- 7.8 versus group 2 64.8 +/- 15.9, p less than 0.0001. These data validate the utility of exercise echocardiography by demonstrating that 1) coronary stenosis severity measured by quantitative angiography is closely related to wall motion abnormalities detected by exercise echocardiography, and 2) exercise echocardiography can be used as a noninvasive means to assess the physiologic significance of coronary artery lesions.     

Embryo fossilization is a biological process mediated by microbial biofilms

Fossilized embryos with extraordinary cellular preservation appear in the Late Neoproterozoic and Cambrian, coincident with the appearance of animal body fossils. It has been hypothesized that microbial processes are responsible for preservation and mineralization of organic tissues. However, the actions of microbes in preservation of embryos have not been demonstrated experimentally. Here, we show that bacterial biofilms assemble rapidly in dead marine embryos and form remarkable pseudomorphs in which the bacterial biofilm replaces and exquisitely models details of cellular organization and structure. The experimental model was the decay of cleavage stage embryos similar in size and morphology to fossil embryos. The data show that embryo preservation takes place in 3 distinct steps: (i) blockage of autolysis by reducing or anaerobic conditions, (ii) rapid formation of microbial biofilms that consume the embryo but form a replica that retains cell organization and morphology, and (iii) bacterially catalyzed mineralization. Major bacterial taxa in embryo decay biofilms were identified by using 16S rDNA sequencing. Decay processes were similar in different taphonomic conditions, but the composition of bacterial populations depended on specific conditions. Experimental taphonomy generates preservation states similar to those in fossil embryos. The data show how fossilization of soft tissues in sediments can be mediated by bacterial replacement and mineralization, providing a foundation for experimentally creating biofilms from defined microbial species to model fossilization as a biological process.     

Differences between men and women on the waiting list for coronary revascularization

This study aims to examine the situation for patients on the waiting list for possible coronary revascularization in terms of waiting time, treatment and various aspects of well-being in relation to gender. Patients on the waiting list for coronary angiography, percutaneous transluminal coronary angioplasty or coronary artery bypass grafting in September 1990 were approached with a questionnaire dealing with various aspects as described above. Of the 831 patients who participated in the evaluation, 174 (21%) were women. Although age was similar for men and women, men had a higher prevalence of previous myocardial infarction and a lower prevalence of previous hypertension. In terms of medication, women were more frequently treated with diuretics and sedatives than men. Women reported a higher frequency than men with regard to the following symptoms: chest pain at rest and at night, dyspnoea when walking, tachycardia, tiredness, headache, dizziness and sweating. Women also suffered more frequently from difficulty going to sleep, difficulty waking up, repeated awakening and insomnia. Men, on the other hand, suffered more frequently from restlessness, inability to act and irritability. Among patients on the waiting list for possible coronary revascularization, women differed from men by being more frequently treated with diuretics, reporting a higher frequency of various cardiovascular symptoms including chest pain and dyspnoea and, furthermore, reporting more sleeping disorders. Gender differences were found but they were not consistent.