Space hardware for concrete sample production on ISS "MASON concrete mixer"

Advances in space flight technology will enable the construction of Moon or even Mars bases in the not-too-distant future. Thus, materials will be needed that are suitable for building in microgravity environments. One idea is to use concrete, the most used construction material on Earth, for these challenging tasks. The hardening and the properties of concrete under the boundary conditions prevailing on Earth are well understood, but there is only limited research on concrete produced in microgravity. Hence, a research project called MASON was established, which aims to mix and harden concrete on the ISS and to investigate the properties of the specimens made in microgravity extensively. Since a defined geometry of the specimens would be favorable for these investigations, a special hardware was developed, called the MASON Concrete Mixer (MCM), which allows the production of concrete specimens fulfilling the requirements on the geometry as well as the safety requirements. Subsequently, the development, design, tests, and qualification of the MCM as well as its usage are presented.

Single chest drain is not inferior to double chest drain after robotic esophagectomy: a propensity score-matched analysis

Background

Chest drain management has a significant influence on postoperative recovery after robot-assisted minimally invasive esophagectomy (RAMIE). The use of chest drains increases postoperative pain by irritating intercostal nerves and hinders patients from early postoperative mobilization and recovery. To our knowledge, no study has investigated the use of two vs. one intercostal chest drains after RAMIE.

Methods

This retrospective cohort study evaluated patients undergoing elective RAMIE with gastric conduit pull-up and intrathoracic anastomosis. Patients were divided into two groups according to placement of one (11/2020-08/2022) or two (08/2018-11/2020) chest drains. Propensity score matching was performed in a 1:1 ratio, and the incidences of overall and pulmonary complications, drainage-associated re-interventions, radiological diagnostics, analgesic use, and length of hospital stay were compared between single drain and double drain groups.

Results

During the study period, 194 patients underwent RAMIE. Twenty-two patients were included after propensity score matching in the single and double chest drain group, respectively. Time until removal of the last chest drain [postoperative day (POD) 6.7 ± 4.4 vs. POD 9.4 ± 2.7, p = 0.004] and intensive care unit stay (4.2 ± 5.1 days vs. 5.3 ± 3.5 days, p = 0.01) were significantly shorter in the single drain group. Overall and pulmonary complications, drainage-associated events, re-interventions, number of diagnostic imaging, analgesic use, and length of hospital stay were comparable between both groups.

Conclusion

This study is the first to demonstrate the safety of single intercostal chest drain use and, at least, non-inferiority to double chest drains in terms of perioperative complications after RAMIE.

Drainless robot-assisted minimally invasive oesophagectomy-randomized controlled trial (RESPECT)

BACKGROUND

The purpose of this randomized trial is to evaluate the early removal of postoperative drains after robot-assisted minimally invasive oesophagectomy (RAMIE). Evidence is lacking about feasibility, associated pain, recovery, and morbidity.

METHODS/DESIGN

This is a randomized controlled multicentric trial involving 72 patients undergoing RAMIE. Patients will be allocated into two groups. The "intervention" group consists of 36 patients. In this group, abdominal and chest drains are removed 3 h after the end of surgery in the absence of contraindications. The control group consists of 36 patients with conventional chest drain management. These drains are removed during the further postoperative course according to a standard algorithm. The primary objective is to investigate whether postoperative pain measured by NRS on the second postoperative day can be significantly reduced in the intervention group. Secondary endpoints are the intensity of pain during the first week, analgesic use, number of postoperative chest X-ray and CT scans, interventions, postoperative mobilization (steps per day as measured with an activity tracker), postoperative morbidity and mortality.

DISCUSSION

Until now, there have been no trials investigating different intraoperative chest drain strategies in patients undergoing RAMIE for oesophageal cancer with regard to perioperative complications until discharge. Minimally invasive approaches combined with enhanced recovery after surgery (ERAS) protocols lower morbidity but still include the insertion of chest drains. Reduction and early removal have been proposed after pulmonary surgery but not after RAMIE. The study concept is based on our own experience and the promising current results of the RAMIE procedure. Therefore, the presented randomized controlled trial will provide statistical evidence of the effectiveness and feasibility of the "drainless" RAMIE.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05553795. Registered on 23 September 2022.

Analysis of predictors for postoperative complications after pancreatectomy--what is new after establishing the definition of postpancreatectomy acute pancreatitis (PPAP)?

PURPOSE

We aimed to analyze the predictive value of hyperamylasemia after pancreatectomy for morbidity and for the decision to perform rescue completion pancreatectomy (CP) in a retrospective cohort study.

METHODS

Data were extracted from a retrospective clinical database. Postoperative hyperamylasemia (POH) and postoperative hyperlipasemia (POHL) were defined by values greater than those accepted as the upper limit at our institution on postoperative day 1 (POD1). The endpoints of the study were the association of POH with postoperative morbidity and the possible predictors for postpancreatectomy acute pancreatitis (PPAP) and severe complications such as the necessity for rescue CP.

RESULTS

We analyzed 437 patients who underwent pancreaticoduodenectomy over a period of 7 years. Among them, 219 (52.3%) patients had POH and 200 (47.7%) had normal postoperative amylase (non-POH) levels. A soft pancreatic texture (odds ratio [OR] 3.86) and POH on POD1 (OR 8.2) were independent predictors of postoperative pancreatic fistula (POPF), and POH on POD1 (OR 6.38) was an independent predictor of rescue CP. The clinically relevant POPF (49.5% vs. 11.4%, p < 0.001), intraabdominal abscess (38.3% vs. 15.3%, p < 0.001), postoperative hemorrhage (22.8% vs. 5.1%, p < 0.001), major complications (Clavien-Dindo classification > 2) (52.5% vs. 25.6%, p < 0.001), and CP (13% vs. 1.8%, p < 0.001) occurred significantly more often in the POH group than in the non-POH group.

CONCLUSION

Although POH on POD1 occurs frequently, in addition to other risk factors, it has a predictive value for the development of postoperative morbidity associated with PPAP and CP.

How we do it-the use of peritoneal patches for reconstruction of vena cava inferior and portal vein in hepatopancreatobiliary surgery

PURPOSE

Extended resections in hepatopancreatobiliary (HPB) surgery frequently require vascular resection to obtain tumor clearance. The use of alloplastic grafts may increase postoperative morbidity due to septic or thrombotic complications. The use of suitable autologous venous interponates (internal jugular vein, great saphenous vein) is frequently associated with additional incisions. The aim of this study was to report on our experience with venous reconstruction using the introperative easily available parietal peritoneum, focusing on key technical aspects.

METHODS

All patients who underwent HPB resections with venous reconstruction using peritoneal patches at our department between January 2017 and November 2021 were included in this retrospective analysis with median follow-up of 2 months (IQR: 1-8 months). We focused on technical aspects of the procedure and evaluated vascular patency and perioperative morbidity.

RESULTS

Parietal peritoneum patches (PPPs) were applied for reconstruction of the inferior vena cava (IVC) (13 patients) and portal vein (PV) (4 patients) during major hepatic (n = 14) or pancreatic (n = 2) resections. There were no cases of postoperative bleeding due to anastomotic leakage. Following PV reconstruction, two patients showed postoperative vascular stenosis after severe pancreatitis with postoperative pancreatic fistula and bile leakage, respectively. In patients with reconstruction of the IVC, no relevant perioperative vascular complications occurred.

CONCLUSIONS

The use of a peritoneal patch for reconstruction of the IVC in HPB surgery is a feasible, effective, and low-cost alternative to alloplastic, xenogenous, or venous grafts. The graft can be easily harvested and tailored to the required size. More evidence is still needed to confirm the safety of this procedure for the portal vein regarding long-term results.

Short-term preoperative drainage is associated with improved postoperative outcomes compared to that of long-term biliary drainage in pancreatic surgery

Purpose

The treatment of choice for patients presenting with obstructive cholestasis due to periampullary carcinoma is oncologic resection without preoperative biliary drainage (PBD). However, resection without PBD becomes virtually impossible in patients with obstructive cholangitis or severely impaired liver cell function. The appropriate duration of drainage by PBD has not yet been defined for these patients.

Methods

A retrospective analysis was conducted on 170 patients scheduled for pancreatic resection following biliary drainage between January 2012 and June 2018 at the University Hospital Dresden in Germany. All patients were deemed eligible for inclusion, regardless of the underlying disease entity. The primary endpoint analysis was defined as the overall morbidity (according to the Clavien-Dindo classification). Secondary endpoints were the in-hospital mortality and malignancy adjusted overall and recurrence-free survival rates.

Results

A total of 170 patients were included, of which 45 (26.5%) and 125 (73.5%) were assigned to the short-term (< 4 weeks) and long-term (≥ 4 weeks) preoperative drainage groups, respectively.

Surgical complications (Clavien-Dindo classification > 2) occurred in 80 (47.1%) patients, with significantly fewer complications observed in the short-term drainage group (31.1% vs. 52%; p = 0.02). We found that long-term preoperative drainage (unadjusted OR, 3.386; 95% CI, 1.507–7.606; p < 0.01) and periampullary carcinoma (unadjusted OR, 5.519; 95% CI, 1.722–17.685; p-value < 0.01) were independent risk factors for postoperative morbidity, based on the results of a multivariate regression model. The adjusted overall and recurrence-free survival did not differ between the groups (p = 0.12).

Conclusion

PBD in patients scheduled for pancreatic surgery is associated with substantial perioperative morbidity. Our results indicate that patients who have undergone PBD should be operated on within 4 weeks after drainage.

Perioperative Blood Management of Preoperative Anemia Determines Long-Term Outcome in Patients with Pancreatic Surgery

BACKGROUND/PURPOSE

Anemia affects the postoperative course of patients undergoing a major surgical procedure. However, it remains unclear whether anemia has a different impact on the long-term outcome of patients with malignant or benign pancreatic disease.

METHODS

A retrospective analysis of patients undergoing pancreatic surgery for pancreatic malignancies or chronic pancreatitis was conducted between January 2012 and June 2018 at the University Hospital Dresden, Germany. The occurrence of preoperative anemia and the administration of pre-, intra-, and postoperative blood transfusions were correlated with postoperative complications and survival data by uni- and multivariate analysis.

RESULTS

A total of 682 patients were included with 482 (70.7%) undergoing surgical procedures for pancreatic malignancies. Univariate regression analysis confirmed preoperative anemia as a risk factor for postoperative complications > grade 2 according to the Clavien-Dindo classification. Multivariate regression analyses indicated postoperative blood transfusion as an independent risk factor for postoperative complications in patients with a benign (OR 20.5; p value < 0.001) and a malignant pancreatic lesion (OR 4.7; p value < 0.01). Univariate and multivariate analysis revealed preoperative anemia and pre-, intra-, and postoperative blood transfusions as independent prognostic factors for shorter overall survival in benign and malignant patients (p value < 0.001-0.01).

CONCLUSION

Preoperative anemia is a prevalent, independent, and adjustable factor in pancreatic surgery, which poses a significant risk for postoperative complications irrespective of the entity of the underlying disease. It should therefore be understood as an adjustable factor rather than an indicator of underlying disease severity.

[Minimally invasive and robot-assisted surgery for pancreatic cystic tumors]

BACKGROUND

The indications for resection of pancreatic cystic lesions (PCL) are often complex and the operative risk has to be balanced against the risk of malignant transformation. The aim of the study was to provide a synopsis of the current treatment results of minimally invasive surgery for PCL.

METHODS

A systematic literature search was performed using the Medline database (PubMed). Subsequently, the retrieved literature was selectively reviewed.

RESULTS

No published prospective randomized controlled trials have yet addressed the comparison of open and minimally invasive surgery of PCL; however, retrospective case studies have demonstrated the feasibility, safety and a comparable morbidity after minimally invasive distal pancreatectomy (DP), pancreatoduodenectomy (PD), central (CP) or total pancreatectomy and enucleation. Whereas most DPs are performed laparoscopically, the experience of minimally invasive PD has been consolidated for the robot-assisted approach but is concentrated in only a few centers. The number of published reports on minimally invasive organ-sparing pancreas procedures (e. g. CP or enucleation) for PCL is scarce; however, the available (selected) results are promising.

CONCLUSION

Minimally invasive surgery for PCL has the potential to reduce the operative trauma to the patients, while at the same time causing comparable or less morbidity. This requires an increasing specialization of complex minimally invasive resections. The clinical use of robotic systems will grow for the latter cases. A prospective registry of the results should be mandatory for quality management.

Management of patients with pancreatic cystic lesions: A case-based survey

BACKGROUND

Pancreatic cystic lesions (PCL), including intraductal papillary mucinous neoplasia (IPMN), harbor different malignant potential and the optimal management is often challenging. The present study aims to depict the compliance of experts with current consensus guidelines and the accuracy of treatment recommendations stratified by the medical specialty and hospital volume.

METHODS

An international survey was conducted using a set of 10 selected cases of PCL that were presented to a cohort of international experts on pancreatology. All presented cases were surgically resected between 2004 and 2015 and histopathological examination was available. Accuracy of the treatment recommendations was based on the European and international consensus guideline algorithms, and the histopathological result.

RESULTS

The response rate of the survey was 26% (46 of 177 contacted experts), consisting of 70% surgeons and 30% gastroenterologists/oncologists (GI/Onc). In the case of main-duct IPMN (MD-IPMN), surgeons preferred more often the surgical approach in comparison with the GI/Onc (55 versus 44%). The mean accuracy rate based on the European and international consensus guidelines, and the histopathological result, were 71/76/38% (surgeons), and 70/73/34% (GI/Onc), respectively. High-volume centers achieved insignificantly higher accuracy scores with regard to the histopathology. Small branch-duct IPMN with cysts <2 cm and malignant potential were not identified by the guideline algorithms.

CONCLUSION

The survey underlines the complexity of treatment decisions for patients with PCL; less than 40% of the recommendations were in line with the final histopathology in this selected case panel. Experts and consensus guidelines may fail to predict malignant potential in small PCL.

[Robot-assisted pancreatic resection]

Although robot-assisted pancreatic surgery has been considered critically in the past, it is nowadays an established standard technique in some centers, for distal pancreatectomy and pancreatic head resection. Compared with the laparoscopic approach, the use of robot-assisted surgery seems to be advantageous for acquiring the skills for pancreatic, bile duct and vascular anastomoses during pancreatic head resection and total pancreatectomy. On the other hand, the use of the robot is associated with increased costs and only highly effective and professional robotic programs in centers for pancreatic surgery will achieve top surgical and oncological quality, acceptable operation times and a reduction in duration of hospital stay. Moreover, new technologies, such as intraoperative fluorescence guidance and augmented reality will define additional indications for robot-assisted pancreatic surgery.

[MBA - The Physician of Tomorrow?]

In den letzten zehn Jahren hat sich das deutsche Gesundheitssystem zunehmend gewandelt. Kliniken stehen unter deutlichem ökonomischen Druck und betriebswirtschaftliches Wissen wird auch für Mediziner immer wichtiger, auch um mit der Klinikverwaltung optimal im Sinne der Patienten zusammenarbeiten zu können. Medizin und Ökonomie stehen hierbei nicht im Widerspruch zueinander. Durch effizientere Leitung einer Abteilung lassen sich häufig Ressourcen einsparen, Prozessabläufe besser gestalten und auch für den Patienten vorteilhafte Ergebnisse bezüglich Service und medizinischer Qualität erzielen.

In den letzten Jahren hat das Angebot an ökonomischen und betriebswirtschaftlichen Zusatzstudiengängen und Weiterbildungsangeboten für Mediziner stetig zugenommen und wird im Folgenden beleuchtet.

CD95 promotes metastatic spread via Sck in pancreatic ductal adenocarcinoma

Cancer stem cells (CSCs) have been implicated in the initiation and maintenance of tumour growth as well as metastasis. Recent reports link stemness to epithelial–mesenchymal transition (EMT) in cancer. However, there is still little knowledge about the molecular markers of those events. In silico analysis of RNA profiles of 36 pancreatic ductal adenocarcinomas (PDAC) reveals an association of the expression of CD95 with EMT and stemness that was validated in CSCs isolated from PDAC surgical specimens. CD95 expression was also higher in metastatic pancreatic cells than in primary PDAC. Pharmacological inhibition of CD95 activity reduced PDAC growth and metastasis in CSC-derived xenografts and in a murine syngeneic model. On the mechanistic level, Sck was identified as a novel molecule indispensable for CD95's induction of cell cycle progression. This study uncovers CD95 as a marker of EMT and stemness in PDAC. It also addresses the molecular mechanism by which CD95 drives tumour growth and opens tantalizing therapeutic possibilities in PDAC.

[Intraductal papillary mucinous neoplasm of the pancreas (IPMN)--standards and new aspects]

Intraductal papillary mucinous neoplasms (IPMN) of the pancreas belong to the heterogeneous group of cystic pancreatic lesions and have been diagnosed more frequently in recent years. Diagnosis and differentiation from other cystic lesions (pseudocysts, serous-cystic neoplasias [SCN], mucinous-cystic neoplasias [MCN], intraductal papillary-mucinous neoplasias [IPMN] and solid pseudopapillary neoplasias [SPN]) is often challenging. IPMN of the pancreas are considered as precursor lesions for the development of invasive pancreatic cancer. However, depending on the morphological (MD-IPMN, BD-IPMN) and histological subtype (intestinal, pancreatobiliary, oncocytic or gastric) the malignant potential of IPMNs varies significantly. Hence, early diagnosis and selection of the appropriate therapeutic strategy is necessary for optimal outcome and cure. There is a strong consensus for the resection of all MD-IPMN. Small BD-IPMN without signs of malignancy can be followed by observation. The increasing understanding of the histopathology and tumour biology of IPMN has led to an amendment of the 2006 International Association of Pancreatology (IAP) guidelines for the treatment of cystic pancreatic tumours. In consideration of recent data, recommendations for observation and/or follow-up of IPMN cannot be given definitely.

[Hospital cooperation models. Safeguarding optimized patient care, medical training and resource utilization]

INTRODUCTION

In the face of continuous medical progress on the one hand and the increasing cost pressure through the diagnosis-related groups (DRG) system with concomitant hospital privatization on the other, pioneering and economical models for modern and competent patient care are required.

METHODS

The cooperation model of the surgical department of the Heidelberg University Hospital is based on patient selection according to the grade of disease complexity and has been successfully developed in Heidelberg since 2005. The long-term results on the basis of actual proceeds are presented.

RESULTS

Cooperation with the Salem Hospital chaired by the director of the University surgical department has been ongoing for 6 years. General visceral surgery cases with low complexity are treated at the secondary cooperation hospitals whereas complex oncological operations of the esophagus, liver, pancreas, rectum or multivisceral resections and transplantations are performed at the University hospital. Optimal utilization of the operative and infrastructural resources of both cooperation partners lead to an improvement in surgical training and proceeds. Likewise, another cooperation with the secondary hospital in Sinsheim, which started 2 years ago, has shown similar positive results. Clinical rotation for surgical residents and attending surgeons guarantee a complete and competent surgical training in the field of general surgery.

CONCLUSIONS

The long-term results indicate that the cooperation model functions to achieve an optimized treatment of patients and an economical win-win situation for all cooperation partners by differential utilization of the available resources in the hospital network.

Evaluation of the International Study Group of Pancreatic Surgery definition of delayed gastric emptying after pancreatoduodenectomy in a high-volume centre

Background

Delayed gastric emptying (DGE) is a common complication after pancreatoduodenectomy. The International Study Group of Pancreatic Surgery (ISGPS) definition of DGE has not been evaluated and validated in a high-volume centre.

Methods

Complete data sets including assessment of gastric emptying were identified from a database of patients undergoing pancreatoduodenectomy between 2001 and 2008. Factors associated with DGE (grades A, B and C) were assessed by univariable and multivariable analyses.

Results

DGE occurred in 340 (44·5 per cent) of 764 patients. Median hospital stay was significantly prolonged in patients with DGE: 13, 21 and 40 days for grades A, B and C respectively versus 11 days for patients without DGE. DGE was associated with prolonged intensive care unit (ICU) admission (at least 2 days): 20·6, 28·6 and 61·8 per cent of those with grades A, B and C respectively versus 9·4 per cent of patients without DGE. Factors independently influencing DGE grade A were female sex, preoperative heart failure and major complications (grade III–V). Validation of the DGE definition revealed that DGE grades A and B were associated with interventional treatment in 20·1 and 44·4 per cent of patients.

Conclusion

The ISGPS DGE definition is feasible and applicable in patients with an uneventful postoperative course. Major postoperative complications and ICU treatment, however, might limit its usefulness. The identified risk factors for DGE are not amenable to perioperative improvement.

[Surgery for pancreatic cancer]

Ductal pancreatic carcinomas are currently the fourth most common fatal cancer disease with a survival rate of less than 5 % when all stages are considered. Other malignant pancreatic tumours have markedly better prognoses. Even after complete resection and adjuvant chemotherapy, the 5-year survival rate amounts to merely 20 - 25%. Besides a high resistance to chemotherapy and early lympho- and haematogenic metastases, the reason for this is often tumour extension beyond the medial and dorsal resection margins. In standardised pathological examinations cancer cells can be detected in the resection margins in about 75 % of the cases, which reflect the aggressive and infiltrative tumour growth and probably explains the high rate of local recurrence. Standard operations for curative tumour resection are the pylorus-preserving pancreatoduodenectomy (PPPD) and the left pancreatic resection with splenectomy in cases of pancreas tail tumours. In high-volume centres the mortality can be reduced to under 3 % and the long-term survival improved with an increase of the resection rate. Considering surgical complications, pancreatic fistulas with a prevalence of up to 10 % play a decisive role. The technique of the pancreatic anastomosis as well as closure of the pancreatic tail thus represents major surgical challenges. In view of the high recurrence rate of pancreatic carcinomas, extended surgical procedures have been examined in numerous studies. Although infiltration of the portal vein is not a contraindication for curative resection with vascular reconstruction which gives comparable survival rates, a radical, extended lymphadenectomy does not seem reasonable on the basis the available data. In selected, individual cases, patients may benefit from neoadjuvant radiochemotherapy to down-stage an unresectable tumour with subsequent tumour resection, a metastasis resection, or a resection of a local recurrence. An R0 resection and tumour-free lymph nodes (N0 stage) are the two factors that can provide the best prognosis for the patient with a median survival of 2 years and a good quality of life. Pancreas surgery is being increasingly oriented to the evidence-based data from randomised, controlled studies. In order to achieve a further and urgently needed improvement in treatment results, one should consider, if possible, all suitable patients for enrolment in current clinical studies on neoadjuvant, surgical, or adjuvant therapy.

C-reactive protein as early predictor for infectious postoperative complications in rectal surgery

BACKGROUND

This study evaluated the role of the acute phase C-reactive protein (CRP) in the postoperative course of a large series of rectal resections on the basis of a prospective database. Main focus of this study was the early identification of complications.

MATERIALS AND METHODS

Three hundred eighty-three rectal resections with primary anastomosis for rectal cancer were screened for infectious postoperative complications. Forty-eight complicated cases were identified and matched with 48 patients with an uneventful postoperative course.

RESULTS

In the postoperative setting, CRP peaked on postoperative day (POD) 2 with a median serum CRP of 140 mg/l and gradually declined thereafter in uncomplicated cases. In complicated cases, CRP elevation generally persisted after POD 2, whereas white blood cells and body temperature were within normal range in the early postoperative period. A cutoff CRP value of 140 mg/dl on PODs 3 and 4 resulted in predictive values of 85.7 and 90.5% (adjusted to the prevalence: 37.6 and 50.3%), sensitivities of 80.0 and 54.3%, and specificities of 81.0 and 92.3% for a complicated postoperative course (P<0.001), respectively.

CONCLUSION

Persistent CRP elevation and elevation of serum CRP above 140 mg/dl on PODs 3-4 are predictive of infectious postoperative complications and should prompt intense clinical search for an inflammatory process, especially for an anastomotic leak if pneumonia and wound infection are unlikely or excluded.

Intratumoural injection of the toll-like receptor-2/6 agonist 'macrophage-activating lipopeptide-2' in patients with pancreatic carcinoma: a phase I/II trial

This phase I/II trial examined safety and efficacy of the toll-like receptor 2/6 agonist MALP-2 in combination with gemcitabine in patients with incompletely resectable pancreas carcinomas. MALP-2 is a toll-like receptor 2/6 agonist, acts as an immunological adjuvant, and has been described recently to prolong survival in a mouse model of an orthotopic, syngeneic pancreas tumour. Male and female patients with incompletely resectable pancreas carcinomas were eligible while those with R0 or R1 resections or with peritoneal carcinosis were excluded. Ten patients were injected intratumourally during surgery with 20-30 microg MALP-2 followed by postoperative chemotherapy. Samples were taken from peripheral blood and wound secretion, and assayed for cell content, cytokine and CRP levels, and NK activity. An MALP-2 dose of 20 microg was well tolerated. Clear signs of local MALP-2 effects were presented by the influx of lymphocytes and monocytes in wound secretions, and abolishment of inhibition of NK activity. The actual mean survival is 17.1+/-4.2 months; the median survival being 9.3 months. Two patients are still alive after 31 months. Up to 20 microg MALP-2 was well tolerated, and no systemic side effects were noted. The mean survival of 17.1 months is remarkably high.

A comprehensive chemoselective and enantioselective 2D-HPLC set-up for fast enantiomer analysis of a multicomponent mixture of derivatized amino acids

A feasibility study on the fast enantioselective two-dimensional HPLC separation of racemic amino acid derivatives is presented. The method involves the on-line coupling of a narrow-bore C18 RP column in the first dimension to a short enantioselective column based on nonporous 1.5 microm particles modified with quinidine carbamate as chiral selector in the second dimension. Conceptually, the system was designed to enable both time-controlled repeated transfer of fractions of the eluate and detector-controlled transfer of selected fractions from column 1 to column 2. To avoid volume overloading of the second chiral column, a narrow-bore reversed phase column was installed in the first dimension. Due to the fast (less than 1.5 minutes) enantiomer separation that occurs in the second dimension, the overall analysis time for the two-dimensional separation of a mixture of nine racemic 3,5-dinitrobenzoyl amino acids was optimized at 16 minutes.

How to increase inflow in liver transplantation

Liver transplantation (LTx) has become the treatment of choice for selected cases of benign and malignant liver disease. Despite becoming increasingly safer in recent years this procedure still incurs several serious postoperative complications. The most significant surgical complications are related to surgical technique, particularly the reconstruction and/or anastomosis of the hepatic artery. Arterial hypoperfusion may lead to graft failure, sepsis, or ischemic biliary lesions. In this review we focus on the Achilles' heel of LTx: the hepatic artery. We provide transplant surgeons with an overview of the technical options that are available to increase arterial inflow and subsequently improve patient outcome. We exemplify some of the discussed techniques using a liver transplant case with an eventful postoperative course because of arterial complications.

[Autoimmune pancreatitis--a surgical disease?]

The term autoimmune pancreatitis (AIP) describes a nonalcoholic, chronic lymphoplasmocytic pancreatitis. The lymphoplasmocytic infiltration is characterized by periductal localization of predominantly CD4-positive T cells, fibrosis, and acinar atrophy, frequently resulting in stenosis of the main pancreatic and distal common bile ducts. Imaging studies often reveal a diffuse narrowing of the pancreatic main duct and swelling of the pancreatic head wrongly suggesting the presence of a malignant tumor. Clinical signs include mild abdominal pain, jaundice, recurrent episodes of acute pancreatitis, and even new-onset diabetes mellitus. Additionally, AIP can be associated with other autoimmune diseases such as Sjögren's syndrome, primary sclerosing cholangitis, chronic inflammatory bowel diseases, and retroperitoneal fibrosis. Serological markers include autoantibodies and increased levels of gamma globulin and especially IgG4. Steroids seem to be effective in improving clinical symptoms as well as in the resolution of pancreatic and bile duct narrowing. This distinguishes AIP from other forms of pancreatitis and from pancreatic neoplasms. Further studies of the underlying pathophysiologic mechanisms, prognosis, and new diagnostic tools are needed to provide adequate and effective treatment in the future. In this article, we summarize the current knowledge about AIP and present 17 cases that underwent surgical resection at our institution from 2003 to 2004.

Selectivity Tuning of Serially Coupled (S,S)Whelk-O 1 and (R,R)Whelk-O 1 Columns in HPLC

The selectivity tuning of two columns coupled in series is investigated in chiral high-performance liquid chromatography. Two columns with reversal enantioselectivities [(R,R) Whelk-O 1 and (S,S) Whelk-O 1] are coupled in series via a T connector. Selectivity of such a column series is tuned by varying the mobile phase flows in the individual columns. The flow ratio necessary for the required selectivity is calculated on the basis of retention factors measured on the individual columns. The performance of this method for adjusting the required selectivity is studied by the separation of enantiomers of alkoxy substituted esters of phenylcarbamic acid. It is demonstrated that the change of the mobile phase flows in the individual columns enables change in the elution order of enantiomers.

Selectivity tuning in chiral dual column gas chromatography

The enantioselective tuning of two columns coupled in series is investigated in chiral high-resolution gas chromatography. Two columns with opposite enantioselectivities (Chirasil-L-Val and Chirasil-D-Val) are coupled in series via a T connector, and the relative retention of enantiomers chromatographed on the system is changed by varying the individual carrier gas flow rates in the coupled columns. The flow-rate ratio necessary for the required selectivity is calculated on the basis of the measured retention factors on the individual columns. The performance of this method for adjusting selectivity is studied by the separation of enantiomers of the N-TFA-O-methyl esters of six amino acids. It is demonstrated that the change of the coupling point carrier gas pressure, at the constant inlet and outlet pressures, may change the enantioselectivity of the given column series to such an extent that the enantiomer elution order may be reversed.

CD2AP and p130Cas localize to different F-actin structures in podocytes

Mice lacking the 80-kDa CD2-associated protein (CD2AP) develop progressive renal failure that starts soon after birth with proteinuria and foot process effacement by unknown mechanisms. CD2AP has been identified and cloned independently by virtue of its interaction with the T cell protein CD2 and with the docking protein p130Cas. In the present study we examined the localization of CD2AP and p130Cas in the mouse glomerulus and in cultured podocytes. In glomeruli, CD2AP and p130Cas immunofluorescence were observed in podocytes, where they colocalized with F-actin in foot processes. In addition, p130Cas was strongly expressed in mesangial cells. Immunoelectron microscopy demonstrated that CD2AP was present in podocyte foot processes without a prevailing localization. In cultured podocytes, p130Cas was enriched at sites of focal adhesions, where it colocalized like vinculin with F-actin at stress fiber ends. In contrast, CD2AP colocalized with F-actin at the leading edge of lamellipodia and in small spots, which were unevenly distributed in the cytoplasm. The spot-shaped F-actin structures were also stained by antibodies against the actin nucleation Arp2/3 complex and cortactin, both contributing to dynamic actin assembly. Moreover, CD2AP spots in cultured podocytes were in close spatial association with actinin-4, but not actinin-1. Our results suggest that CD2AP and p130Cas, which both colocalize with F-actin in podocytes in situ, possess different functions. Whereas p130Cas is found in focal adhesions, CD2AP seems to be involved in the regulation of highly dynamic F-actin structures in podocyte foot processes.

Influence of buffer zone concentrations on efficiency in partial filling micellar electrokinetic chromatography

The potential of counter pressure-moderated partial filling micellar electrokinetic chromatography (PF-MEKC) was investigated in this work. Plate numbers of homologous omega-phenylalcohols were measured in a two-plug PF-MEKC system varying the concentrations and hence the ionic strengths of the background buffer compared to the sodium dodecyl sulfate-containing separation buffer and the counter pressure on the cathodic buffer reservoir. It was observed that plate numbers are strongly influenced by both the buffer concentrations and the counter pressure. Highest plate numbers were obtained with a buffer system where the concentrations are adjusted such that the electroosmotic flow velocities in both zones are equal. Differences in the local electroosmotic flow velocities of the zones caused by different buffer concentrations are responsible for tremendously reduced plate numbers. The efficiency drop is explained in several models by the formation of an intersegmental pressure which produces a parabolically shaped laminar flow component in both zones. Thus, the electroosmotic plug-like flow profile is distorted and the efficiency is reduced. The effect of counter pressure on efficiency turned out to be very complex in dependence on the buffer system applied.

Moderation of the electroosmotic flow in capillary electrophoresis by chemical modification of the capillary surface with tentacle-like oligourethanes

The surface chemistry of the inner wall of fused-silica capillaries is one important means to control the magnitude as well as the direction of the electroosmotic flow and the adsorption activity. A method was developed to change the surface characteristics of fused-silica capillaries by binding tentacle-like oligourethane groups onto the inner surface. The electroosmotic flow at a buffer pH of 6-9 was reduced by 15 to 40% compared to that in a bare fused-silica tubing, dependent on the type of coating. Sample adsorption is diminished at the same time resulting in a separation of proteins with higher resolution and good migration time precision. At a pH below 4.5 the electroosmotic flow is reversed into the anodic direction, which offers further possibilities for the separation of positively charged analytes as demonstrated for the separation of aromatic and biogenic amines.

Role of phosphodiesterases in the regulation of endothelial permeability in vitro

Neutrophil-derived hydrogen peroxide (H2O2) is believed to play an important role in the pathogenesis of vascular injury and pulmonary edema. H2O2 time- and dose-dependently increased the hydraulic conductivity and decreased the selectivity of an endothelial cell monolayer derived from porcine pulmonary arteries. Effects of H2O2 on endothelial permeability were completely inhibited by adenylate cyclase activation with 10(-12) M cholera toxin or 0.1 microM forskolin. 10(-8) M Sp-cAMPS, a cAMP-dependent protein kinase A agonist, was similarly effective. The phosphodiesterase (PDE) inhibitors motapizone (10(-4) M), rolipram (10(-6) M), and zardaverine (10(-8) M), which specifically inhibit PDE-isoenzymes III, IV, and III/IV potently blocked H2O2-induced endothelial permeability when combined with 10(-6) M prostaglandin E1. Overall cellular cAMP content and inhibition of H2O2 effects on endothelial permeability were poorly correlated. H2O2 exposure resulted in a rapid and substantial decrease in endothelial cAMP content. The analysis of the PDE isoenzyme spectrum showed high activities of isoenzymes II, III, and IV in porcine pulmonary endothelial cells. The data suggest that adenylate cyclase activation/PDE inhibition is a powerful approach to block H2O2-induced increase in endothelial permeability. This concept appears especially valuable when endothelial PDE isoenzyme pattern and PDE inhibitor profile are matched optimally.

[Examples for using capillary gas chromatography with wide bore columns in occupational health]

Wide bore capillary columns (0.4-0.75 mm ID) can be easily and inexpensively installed in packed column GCs. The analytical advantages cause an expanding market for such capillaries and interconverting hardware kits. It is illustrated with some examples that often individual exposition levels can be determined exactly only by using capillary columns: ethylbenzene may be separated from the C8-isomers also in complex mixtures, the marker PBN for rubber smoke expositions can be determined with 30 min sampling time, the detection sensitivity of the FID is sufficient also for chlorinated pesticides and the analyses of high-boiling compounds profit by the high phase ratio of wide bore capillary columns. A single capillary column substitutes a variety of different packed columns, so saving time and money and protecting the analyst from failures and frustrating compromises.