Stefan A. Müller

Experimental evaluation of phospholipids and icodextrin in re-formation of peritoneal adhesions.

The formation of further adhesions after adhesiolysis is a major problem. Not all agents that are supposed to reduce de novo adhesions can reduce further adhesion formation. The efficacy and safety of intraperitoneally applied phospholipids has been shown previously. This study evaluated the influence of phospholipids and icodextrin on adhesion re‐formation.

Phospholipids reduce adhesion formation in the rabbit uterine horn model

OBJECTIVE To access the ability of intraperitoneal phospholipids to reduce adhesions in a standardized model for gynecologic operations. DESIGN A randomized, experimental, blinded study using the double uterine horn model. SETTING Academic animal research laboratory. ANIMAL(S) Thirty-three Chinchilla rabbits. INTERVENTION(S) Phospholipids or Ringers lactate were intraperitoneally administered after bilateral uterine horn injury. MAIN OUTCOME MEASURE(S) After 10 days, adhesions were evaluated concerning area and strength as well as scores describing tenacity and degree. RESULT(S) Phospholipids (median 102.1 mm2) significantly reduce adhesion areas in comparison to surgical controls (median 392.2 mm2) and Ringer group (median 323.8 mm2). Scores reflecting severity and degree of adhesions support this finding. CONCLUSION(S) These results prove the efficacy of phospholipids in the double uterine horn model. Future clinical studies are recommended.

The influence of blood on the efficacy of intraperitoneally applied phospholipids for prevention of adhesions

BackgroundThe formation of adhesions following abdominal surgery is a well known problem. In previous studies we demonstrated the efficacy and safety of intraperitoneally applied phospholipids in order to prevent adhesion formation. This study evaluates the influence of blood on the efficacy of intraperitoneally applied phospholipids for prevention of adhesions.MethodsIn 40 Chinchilla rabbits adhesions were induced by median laparotomy, standardized abrasion of the visceral and parietal peritoneum in defined areas of the ventral abdominal wall and the caecum. The animals were randomly divided into four groups. They received either phospholipids 3.0% or normal saline (NaCl 0,9%) (5 ml/kg body weight). In 50% of the rabbits we simulated intraperitoneal bleeding by administration of blood (1,5 ml/kg body weight). The other half served as control group. Ten days following the operation the animals were sacrificed and adhesion formation was assessed by computer aided planimetry and histopathologic examination.ResultsThe median adhesion surface area in the NaCl-group (n = 9) amounted to 68,72 mm2, in the NaCl+Blood-group (n = 10) 147,68 mm2. In the Phospholipid (PhL)-group (n = 9) the median adhesion surface area measured 9,35 mm2, in the PhL+Blood-group (n = 9) 11,95 mm2. The phospholipid groups had a significantly smaller adhesion surface area (p < 0.05).ConclusionAgain these results confirm the efficacy of phospholipids in the prevention of adhesions in comparison to NaCl (p = 0,04). We also demonstrated the adhesion preventing effect of phospholipids in the presence of intraperitoneal blood.

Current-steering DAC linearisation by impedance transformation

This paper proposes the design of a load-network for the current-steering DAC which highly enhances its performance. Foremost, the effect of the load-network on the DACs performance is analysed. Based on this analysis design specifications for a linear 12+1 bit DAC are derived. The presented circuit implementation is a 4th order lowpass realizing broadband impedance transformation in the 65 nm TSMC process. This design makes an operation from 4 to 6 GHz possible. The proposed load-network enhances the error-vector-magnitude by 4.8 dB in contrast to a 50 Ω-load.

Einfluss von Phospholipiden und Icodextrin auf Infektion und Adhäsionen bei Peritonitis

Background Bacterial peritonitis is a strong promoter of adhesion formation besides mechanical, chemical, thermic, and ischemic trauma. In the present study the usefulness of fluid devices, that worked efficaciously in other, non infectious models, was evaluated in a standardized rat peritonitis model.

Phospholipide reduzieren Adhäsionen im Uterus-Horn-Modell beim Kaninchen

Background. Adhesion formation following gynecologic or visceral surgery is a major cause of female infertility. Further sequelae are recurrent and chronic abdominal complaints and pain. Adjuvant therapy is needed to prevent adhesion formation as an important reason for postoperative morbidity and mortality. Previously published data proved the efficacy of phospholipids (PL) for this indication. This study was designed to access the ability of intraperitoneal phospholipids to reduce adhesions in a standardized model for gynecologic operations. Materials and Methods: A total of 33 female Chinchilla rabbits were included in this study. After lower midline incision a 5 cm segment the uterine horns were abraded circularly and ischemia was induced by removal of the collateral blood supply. The operation was completed by intraperitoneal administration of 5.0 ml per kg body weight of phospholipids (75 mg per kg body weight) or the same volume of Ringer‘s lactate solution. In animals assigned to the surgical control group, the abdomen was closed without additional treatment. After 10 days the animals were sacrificed and adhesions were examined and scored concerning severity and tenacity. The force of adhesions measuring larger than 25 mm2 were assessed using a spring scale (values in Newton). After subtle dissection the areas of adhesions (mm2) were measured using a digitizer board and a custom-made software on a personal computer. Results: The mean area of adhesions in the surgical control group amounted to 394.0 mm2 ±41.9 mm2 (median 392.2 mm2) in comparison to 384.2 ± 67.0 mm2 (median 323.8 mm2) in the Ringer group and 110.3 mm2 ±25.1 mm2 (median 102.1mm2) in the phospholipid (PL) group. The comparison of the control group and the Ringer group versus the PL group were significant (p < 0.05). The differences in the severity score and the degree score according to Leach between surgical controls and PL as well as Ringer and PL were significant (p < 0.05). The differences of the force to tear apart the adhesions were significant (p < 0.05). Statistical analysis of the force correlated with the area of the measured adhesions revealed no significant difference. Conclusions: These results prove the efficacy of phospholipids in the double uterine horn model. Further clinical studies are recommended.

Auswirkungen der intraabdominellen Applikation von Phospholipiden auf Wundheilung und Adhäsionsbildung

Background: Adjuvant therapy is needed to prevent adhesion formation as a major cause of postoperative morbidity and mortality. Previously published data proved the efficacy of phospholipids (PL) for this indication; however, additional information on drug safety was still outstanding. This study was designed to investigate the influence of phospholipids on three different types of healing tissue. Materials and Methods: A total of 48 Chinchilla rabbits underwent median laparotomy, standardized abrasion of the visceral and parietal peritoneum, jejunal anastomosis, and an electrocautery incision of the liver. The operation was completed by intraperitoneal administration of 10 ml/kg of either normal saline (NaCl, 0.9%) or phospholipids (PL, 12%). After intervals of 5 and 10 days, respectively, 50% of the surviving animals were sacrificed and adhesions were measured using a digitizer board. The fresh 10-cm long segment of the jejunum carrying the anastomosis was examined using a bursting experiment. Tensile strength of the midline laparotomy wound was assessed. Specimens of the scar tissue of liver, anastomosis, and abdominal wall were stained with Sirius red and Fast green to determine the collagen protein ratio. Results: After 5 (NaCl 691 mm2 vs. PL 192 mm2 ) and after 10 days (NaCl 625 mm2 vs. PL 88 mm2) the control group presented with significantly larger adhesion areas (p < 0.05). The bursting pressure of the anastomosis on the fifth (NaCl 16.1 kPa vs. PL 18.2 kPa) and tenth (NaCl 19.7 kPa vs. PL 18.6 kPa) postoperative day showed no statistically significant difference. The tensile strength of the laparotomy wound measured after intervals of 5 (NaCl 8.5 N cm-1 vs. PL 6.8 N cm-1) and 10 days (NaCl 23.0 N cm-1 vs. PL 20.2 N cm-1) was not statistically different either. The collagen protein ratio of anastomoses, laparotomy wounds, and liver incisions, as well as the inflammatory reparative response of the different tissues, were not affected by PL. Conclusions: These results prove the efficacy of phospholipids in adhesion prevention. The findings of uncompromised healing of anastomoses, laparotomy wounds, and liver incisions reveal the safety of this agent. Further data may qualify phospholipids for a clinical trial.

Hat der Stent den Tubus in der palliativen, endoskopischen Therapie inoperabler Ösophagus- und Kardiakarzinome abgelöst?

Mit Einfuhrung der Stentimplantation hat die palliative Therapie der malignen Osophagus- und Kardiastenosen, insbesondere bei hochgradigen und verwinkelten Befunden, ein sicheres Verfahren hinzugewonnen. Die Stentimplantation zeichnet sich besonders durch ihre niedrige Fruhkomplikationsrate bei einfacher Plazierungstechnik aus. Bei den Spatkomplikationen, dem technischen Erfolg und der Senkung des Dysphagiegrades zeigen sich zwischen Tubus- und Stentimplantation keine signifikanten Unterschiede. Eine gefurchtete Komplikation des Stents ist die Drucknekrose mit Gefasarrosion. Unter zunehmendem Kostendruck ist der Tubus bei mittelgradigen Stenosen durchaus eine Alternative.