High-precision Absolute Distance and Vibration Measurement using Frequency Scanned Interferometry

In this paper, we report high-precision absolute distance and vibration measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distance was determined by counting the interference fringes produced while scanning the laser frequency. A high-finesse Fabry-Perot interferometer(F-P) was used to determine frequency changes during scanning. Two multiple-distance-measurement analysis techniques were developed to improve distance precision and to extract the amplitude and frequency of vibrations. Under laboratory conditions, measurement precision of $\sim$ 50 nm was achieved for absolute distances ranging from 0.1 meters to 0.7 meters by using the first multiple-distance-measurement technique. The second analysis technique has the capability to measure vibration frequencies ranging from 0.1 Hz to 100 Hz with amplitude as small as a few nanometers, without a priori knowledge.Comment: 16 pages, 7 figures, 1 table, accepted for publication in Applied Optic

Comparison of the collagen haemostat Sangustop(R) versus a carrier-bound fibrin sealant during liver resection; ESSCALIVER-study

Background: Haemostasis in liver surgery remains a challenge despite improved resection techniques. Oozing from blood vessels too small to be ligated necessitate a treatment with haemostats in order to prevent complications attributed to bleeding. There is good evidence from randomised trials for the efficacy of fibrin sealants, on their own or in combination with a carrier material. A new haemostatic device is Sangustop(R). It is a collagen based material without any coagulation factors. Pre-clinical data for Sangustop(R) showed superior haemostatic effect. This present study aims to show that in the clinical situation Sangustop(R) is not inferior to a carrier-bound fibrin sealant (Tachosil(R)) as a haemostatic treatment in hepatic resection. Methods: This is a multi-centre, patient-blinded, intra-operatively randomised controlled trial. A total of 126 patients planned for an elective liver resection will be enrolled in eight surgical centres. The primary objective of this study is to show the non-inferiority of Sangustop(R) versus a carrier-bound fibrin sealant (Tachosil(R)) in achieving haemostasis after hepatic resection. The surgical intervention is standardised with regard to devices and techniques used for resection and primary haemostasis. Patients will be followed-up for three months for complications and adverse events. Discussion: This randomised controlled trial (ESSCALIVER) aims to compare the new collagen haemostat Sangustop(R) with a carrier-bound fibrin sealant which can be seen as a "gold standard" in hepatic and other visceral organ surgery. If non-inferiority is shown other criteria than the haemostatic efficacy (e.g. costs, adverse events rate) may be considered for the choice of the most appropriate treatment. Trial Registration: NCT0091861

Mediators of leukocyte yctivation play a role in disseminated intravascular coagulation during orthotopic liver transplantation

Leukocytes play an important role in the development of disseminated intravascular coagulation (DIC). In the reperfusion phase of OLT a DIC-like situation has been described and has been held responsible for the high blood loss during this phase. We investigated the role of leukocytes in the pathogenesis of DIC in OLT by measuring the leukocytic mediators released upon activation (cathepsin B, elastase, TNF, neopterin) and the levels of thrombin-antithrombin III (TAT) complexes, seen as markers of prothrombin activation. Arterial blood samples were taken at 10 different time points during and after OLT. Samples were also taken of the perfusate released from the liver graft vein during the flushing procedure before the reperfusion phase. Aprotinin was given as a continuous infusion (0.2-0.4 Mill. KlU/hr) and its plasma levels were determined. Significantly elevated levels of neopterin (15-fold; P<0.01), cathepsin B (440-fold; P<0.01) in the perfusate, as compared with the systemic circulation, as well as their significant increases in the early reperfusion phase suggested that they were released by the graft liver. This was paralleled by elevated levels of elastase (1.3-fold, P<0.05), TNF (1.5-fold, P=NS), and TAT complexes (1.4-fold; P<0.1) in the perfusate. Significant correlations could be identified between the parameters of leukocyte activation and TAT complexes, whereas no correlation was observed between any of the parameters investigated and the aprotinin levels. Our results strongly indicate a release of leukocytic mediators from the graft liver during its reperfusion which seems to be related to the parallely increased prothrombin activation. No correlation could be seen between levels of aprotinin and levels of leukocytic mediators

Different aprotinin applications influencing hemostatic chances in orthotopic liver transplantation

The effect of different aprotinin applications on hemmtatic changes and blood product requirements in orthotopic liver transplantation was investigated in a prospective, open, and randomized study. From November 1989 to June 1990, 13 patients received aprotinin as a bolus of 0.5 Mill, kallikrein inac-tivator units (KIU) on three occasions in the course of an OLT, whereas 10 other patients were treated with continuous aprotinin infusion of 0.1-0.4 Mill. KIU/hr. Before and after reperfusion of the graft liver, signs of hyperfibrinolysis, measured by thrombelastography, were significantly lower in the infusion group. Tissue-type plasminogen activator (t-PA) activity increased during the anhepatic phase but to a significantly lesser extent in the infusion group. Blood product requirements during OLT were tendentiously higher in the bolus group but not significantly so. However, the use of packed red blood cells was significantly lower in the postoperative period, whereas there was no significant difference in fresh frozen plasma requirements between the two groups. All 23 patients have survived, and only one woman of each group required retransplantation due to severe host-versus-graft reactions. Furthermore, we investigated the perfusate of the graft liver in both groups and detected signs of a decreased t-PA release in the infusion group. Our results demonstrate an advantage of aprotinin given as continuous infusion over bolus application in OLT

High-precision Absolute Distance Measurement using Dual-Laser Frequency Scanned Interferometry Under Realistic Conditions

In this paper, we report on new high-precision absolute distance measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distances were determined by counting the interference fringes produced while scanning the frequencies of the two chopped lasers. High-finesse Fabry-Perot interferometers were used to determine frequency changes during scanning. Dual lasers with oppositely scanning directions, combined with a multi-distance-measurement technique previously reported, were used to cancel drift errors and to suppress vibration effects and interference fringe uncertainties. Under realistic conditions, a precision about 0.2 microns was achieved for a distance of 0.41 meters.Comment: 14 pages, 5 figures, submitted to Applied Optic

SEMS vs cSEMS in duodenal and small bowel obstruction : high risk of migration in the covered stent group

Aim: To compare clinical success and complications of uncovered self-expanding metal stents (SEMS) vs covered SEMS (cSEMS) in obstruction of the small bowel. Methods: Technical success, complications and outcome of endoscopic SEMS or cSEMS placement in tumor related obstruction of the duodenum or jejunum were retrospectively assessed. The primary end points were rates of stent migration and overgrowth. Secondary end points were the effect of concomitant biliary drainage on migration rate and overall survival. The data was analyzed according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Results: Thirty-two SEMS were implanted in 20 patients. In all patients, endoscopic stent implantation was successful. Stent migration was observed in 9 of 16 cSEMS (56%) in comparison to 0/16 SEMS (0%) implantations (P = 0.002). Stent overgrowth did not significantly differ between the two stent types (SEMS: 3/16, 19%; cSEMS: 2/16, 13%). One cSEMS dislodged and had to be recovered from the jejunum by way of laparotomy. Time until migration between SEMS and cSEMS in patients with and without concomitant biliary stents did not significantly differ (HR = 1.530, 95%CI 0.731-6.306; P = 0.556). The mean follow-up was 57 ± 71 d (range: 1-275 d). Conclusion: SEMS and cSEMS placement is safe in small bowel tumor obstruction. However, cSEMS is accompanied with a high rate of migration in comparison to uncovered SEMS

Anastomoseninsuffizienz nach kolorektalen Resektionen : welche Aussagekraft hat der Verlauf des C-reaktiven Proteins (CRP)?

Einleitung: Anastomoseninsuffizienzen sind schwerwiegende Komplikationen nach Kolonresektionen. Nur selten sind klinische oder laborchemische Zeichen Vorboten einer Insuffizienz. Material und Methoden: Wir haben unser Patientenkollektiv nach kolorektalen Resektionen retrospektiv untersucht in Hinblick auf einen Anstieg des C-rektiven Proteins (CRP) postoperativ als Zeichen einer Insuffizienz. Hierzu wurde der Unterschied vom präoperativen Messwert zum Messwert am 1. bis 7. postoperativen Tag berechnet. Bei Patienten mit Anastomoseninsuffizienz wurden die Werte nur bis zum Tag der Insuffizienz einbezogen, um einen Anstieg durch eine eventuelle Revision auszuklammern. Ergebnisse: Im Zeitraum von 8/2002 bis 8/2005 wurden bei 342 Patienten eine Kolonresektion durchgeführt. Im einzelnen waren dies 101 (29,5%) Sigmaresektionen, 89 (26,0%) Hemikolektomien rechts, 56 (16,4%) Rektumresektionen, 38 (11,1%) Ileocoecalresektionen, 24 (7,0%) Hemikolektomien links, 22 (6,4%) Segmentresektionen, 12 (3,5%) Kolektomien. Das Alter der Patienten lag bei 61,6 +/- 15,0 Jahren. Es wurden 142 (41,5%) Frauen und 200 (58,5%) Männer operiert, 301 (88%) Patienten elektiv und 41 (12%) als Notfall. Die Inzidenz von symptomatischen und asymptomatischen Anastomosen-insuffizienzen lag im Gesamtkollektiv bei 26/342 (7,6%), sie traten durchschnittlich 8,7 +/- 7,1 (1-27) Tage nach der Operation auf. Eine Analyse der CRP-Werte ergab bei den Patienten die im Verlauf eine Anastomoseninsuffizienz entwickelten signifikant höhere Anstiege von präoperativ bis zum 3. (+10,9 mg/dl versus +16,5 mg/dl, p=0,018), 5. (+4,2 mg/dl versus +13,1 mg/dl, p=0,002), 6. (+3,8 mg/dl versus +14,6 mg/dl, p=0,002), und 7. (+2,8 mg/dl versus +18,3 mg/dl, p<0,001) postoperativen Tag. Die Differenz zum 4. postoperativen Tag zeigte keinen signifikanten Unterschied (+6,5 mg/dl versus +11,2 mg/dl, p=0,3). Die absoluten Messwerte waren nicht signifikant unterschiedlich. Andere Laborparameter wie Leukozyten, Kreatinin, Albumin ergaben keinen Unterschied im Vergleich der beiden Gruppen.Die Untersuchung von Risikofaktoren für eine Anastomoseninsuffizienz konnte keinen signifikanten Unterschied zeigen für: Alter, Geschlecht, ASA, OP-Dauer, Zugang (offen oder laparoskopisch), benigne oder maligne Erkrankung, Kolon- oder Rektumresektion, elektive oder Notfalloperation. Schlussfolgerung: Der Verlauf des CRP ist ein signifikanter Marker für das Auftreten von Anastomoseninsuffizienzen nach kolorektalen Resektionen

Combined transarterial chemoembolization and arterial administration of Bletilla striata in treatment of liver tumor in rats

AIM: To evaluate and compare the effect of combined transarterial chemoembolization (TACE) and arterial administration of Bletilla striata (a Chinese traditional medicine against liver tumor) versus TACE alone for the treatment of hepatocellular carcinoma (HCC) in ACI rats. METHODS: Subcapsular implantation of a solid Morris hepatoma 3 924A (2 mm3) in the liver was carried out in 30 male ACI rats. Tumor volume (V1) was measured by magnetic resonance imaging (MRI) on day 13 after implantation. The following different agents of interventional treatment were injected after retrograde catheterization via gastroduodenal artery (on day 14), namely, (A) TACE (0.1 mg mitomycin + 0.1 ml Lipiodol) + Bletilla striata (1.0 mg) (n=10); (B) TACE + Bletilla striata (1.0 mg) + ligation of hepatic artery (n=10), (C) TACE alone (control group, n=10). Tumor volume (V2) was assessed by MRI (on day 13 after treatment) and the tumor growth ratio (V2/V1) was calculated. RESULTS: The mean tumor volume before (V1) and after (V2) treatment was 0.0355 cm3 and 0.2248 cm3 in group A, 0.0374 cm3 and 0.0573 cm3 in group B, 0.0380 cm3 and 0.3674 cm3 in group C, respectively. The mean ratio (V2/V1) was 6.2791 in group A, 1.5324 in group B and 9.1382 in group C. Compared with the control group (group C), group B showed significant inhibition of tumor growth (P0.05). None of the animals died during implantation or in the postoperative period. CONCLUSION: Combination of TACE and arterial administration of Bletilla striata plus ligation of hepatic artery is more effective than TACE alone in the treatment of HCC in rats