[Comparison of Two Umbilicoplasty Techniques in 72 Patients after Breast Reconstruction with a Free DIEP Flap] / Vergleich zweier Techniken der Umbilikoplastik bei 72 Patientinnen nach Brustrekonstruktion mit freier DIEP-Lappenplastik.

INTRODUCTION: The appearance of the umbilicus after DIEP flap surgery or abdominoplasty plays an important role in aesthetic perception (1). Although the umbilicus has no function, there is no doubt about the importance of its shape for the self-esteem of patients, especially after breast cancer (2). In the present study, we compared two of the preferred techniques described in the literature on 72 patients in terms of aesthetic outcome, complications and sensitivity: the caudal flap (domed shape) and the oval shape of the umbilicus. PATIENTS AND METHODS: Seventy-two patients who underwent a DIEP flap for breast reconstruction between January 2016 and July 2018 were retrospectively included in this study. Two techniques for umbilical reconstruction were compared: the transverse oval shape of the umbilicus and umbilicoplasty using a caudal flap, which results in a dome shape of the umbilicus. To compare the aesthetic results, an evaluation by the patients and an assessment by three independent plastic surgeons were carried out at least 6 months postoperatively. Patients and surgeons were asked to rate the general appearance of the umbilicus, including scarring and shape, on a scale from 1 to 6 (1=very good, 2=good, 3=fair, 4=sufficient, 5=poor, 6=insufficient). Furthermore, the occurrence of wound healing disorders was examined, and patients were asked about the sensitivity of the umbilicus. RESULTS: Both techniques showed similar degrees of aesthetic satisfaction (p=0,49) as part of the patients' self-assessment. The plastic surgeons gave the caudal flap technique a significantly better rating than the umbilicus with a transverse oval shape (p=0,042). More wound healing disorders occurred in the caudal lobule (11,1%) compared with the transverse oval umbilicus. However, this was not significant (p=0,16). A surgical revision was not necessary. The caudal flap umbilicus showed a tendency to improved sensitivity (60 vs. 45%), but this was not significant (p=0,19). CONCLUSION: Patient satisfaction showed similar results for the two methods of umbilicoplasty. On average, both techniques were given a good rating for their results. However, surgeons rated the caudal flap umbilicoplasty as more aesthetically pleasing.

Topische Applikation von Tranexamsäure im Rahmen der subkutanen Mastektomie bei Frau-zu-Mann Transidentität.

INTRODUCTION: Tranexamic acid (TXA) is an antifibrinolytic drug that can be used to treat and prevent bleeding. Its application in plastic and reconstructive surgery has been very limited to date. To our knowledge, there is a lack of published data on the topical application of TXA in transgender patients undergoing subcutaneous mastectomy. METHODS: We performed a retrospective data analysis of female-to-male transgender patients who underwent subcutaneous mastectomy. A total of 22 patients were treated with topical TXA, while 29 patients served as controls. The primary endpoint was the amount of wound secretion in the first 48 hours after surgery. Secondary endpoints were the duration of drainage and the occurrence of postoperative bleeding. RESULTS: Within the first 48 hours, the TXA group had an average drain volume of 97±50 ml compared with 180±111 ml in the control group (p<0.01). There was a significantly lower flow rate over the entire period in the group of TXA patients (113±86 ml vs. 265±197 ml). The time of drains in situ was 2.3±0.7 days in TXA patients, while the drains in the control group were in place for an average of 3.4±1.3 days (p<0.01). In the group of patients treated with TXA, there was a tendency towards a lower number of postoperative bleeding and haematoma (9vs. 17%). DISCUSSION: There was a significant reduction in the amount of drain fluid within the first 48 hours and over the entire period after topical application of TXA. Also there was a reduction in the length of time patients had a drain in place in the TXA-treated patients. This study demonstrated a significant advantage for the topical application of TXA in subcutaneous mastectomy in female-to-male transgender patients.

Mechanistic insights into heterogeneous zinc dicarboxylates and theoretical considerations for CO2-epoxide copolymerization.

Copolymerization of epoxides and CO(2) with heterogeneous zinc dicarboxylates is prominent since the early days of this area of chemistry. However, in over 30 years of research, the efficiency of this catalyst system could not be improved significantly. Furthermore, a huge activity difference between zinc glutarate and its lower homologue zinc succinate exists, which could not be explained so far. A detailed investigation of the underlying copolymerization mechanisms on heterogeneous catalysts is therefore necessary. Such investigations are so far lacking, which renders logical improvements of the catalysts difficult. We therefore decided to conduct a detailed investigation on the different zinc-dicarboxylic catalysts, their copolymerization efficiency, solid state structure and supplemented the results with theoretical calculations. The results imply that the widely discussed bimetallic mechanism (for homogeneous catalysts) is in place for heterogeneous zinc dicarboxylates as well. Theoretical calculations conducted to identify an "ideal" Zn-Zn distance suggest an optimal separation of Zn atoms in the range of 4.3-5.0 Å. The combined copolymerization experiments and calculated models give a consistent explanation for the difference in activity of the different zinc-dicarboxylate catalysts and give a hint why the activity of the heterogeneous zinc-dicarboxylate system is limited.

Differences in reactivity of epoxides in the copolymerisation with carbon dioxide by zinc-based catalysts: propylene oxide versus cyclohexene oxide.

The homogeneous dinuclear zinc catalyst going back to the work of Williams et al. is to date the most active catalyst for the copolymerisation of cyclohexene oxide and CO(2) at one atmosphere of carbon dioxide. However, this catalyst shows no copolymer formation in the copolymerisation reaction of propylene oxide and carbon dioxide, instead only cyclic carbonate is found. This behaviour is known for many zinc-based catalysts, although the reasons are still unidentified. Within our studies, we focus on the parameters that are responsible for this typical behaviour. A deactivation of the catalyst due to a reaction with propylene oxide turns out to be negligible. Furthermore, the catalyst still shows poly(cyclohexene carbonate) formation in the presence of cyclic propylene carbonate, but the catalyst activity is dramatically reduced. In terpolymerisation reactions of CO(2) with different ratios of cyclohexene oxide to propylene oxide, no incorporation of propylene oxide can be detected, which can only be explained by a very fast back-biting reaction. Kinetic investigations indicate a complex reaction network, which can be manifested by theoretical investigations. DFT calculations show that the ring strains of both epoxides are comparable and the kinetic barriers for the chain propagation even favour the poly(propylene carbonate) over the poly(cyclohexene carbonate) formation. Therefore, the crucial step in the copolymerisation of propylene oxide and carbon dioxide is the back-biting reaction in the case of the studied zinc catalyst. The depolymerisation is several orders of magnitude faster for poly(propylene carbonate) than for poly(cyclohexene carbonate).

[Treatment of phyllodes tumours of the breast: evaluation of 66 cases and literature review]. / Zur Therapie von Phylloides-Tumoren der Brust ­ eine Aufarbeitung von 66†Fällen mit Literaturübersicht.

Phyllodes tumours (PTs) of the breast are classified as benign, borderline and malignant based on the constellation of defined histological parameters. Surgical excision is the primary therapy, but the need to maintain certain safety margins is still controversially discussed for all three categories.This paper aims to provide a critical opinion on the existing recommendation on safety margins for resection.In our breast centre, all patients with phyllodes tumours were identified retrospectively on the basis of the histopathological documentation from 1999 to 2018. The cases were evaluated, in particular, with a view to recurrences and the occurrence of multicentricity.A total of 66 patients were diagnosed with a PT. In 38 cases, the tumours were benign, in 15 borderline and in 13 malignant. Local recurrences were observed in one benign PT, 7 borderline and 5 malignant PTs. Two PTs that were initially classified as borderline tumours progressed to malignant PTs. Multicentricity occurred in about 20 % of borderline and malignant PTs but only in 5 % of benign PTs.The resection margins for phyllodes tumours should be chosen depending on dignity and recurrence. The key question to be challenged is whether or not there is a need to maintain a certain safety margin in benign PTs. In case of recurrence of borderline or malignant PTs, a mastectomy should be considered early.

Conformationally flexible dimeric salphen complexes for bifunctional catalysis.

Appropriate modification of the salphen ligand allows an easy modular design of flexibly linked dimeric salphen species and their complexes, which can act as bifunctional catalysts. A series of chromium salphen systems including monomeric compound and dimers with different spacer lengths were tested for their catalytic performance in ß-butyrolactone polymerization and CO(2)/propylene oxide copolymerization toward biodegradable materials. The results clearly show an enhancement in activity upon dimerization, thus underlining the role of bifunctional catalysis in the studied processes and extending the possible strategies for improvement of catalysts in these reactions.

[Long-term results after reconstruction of the nipple-areola complex]. / Langzeitergebnisse nach Rekonstruktion des Mamillen-Areola-Komplexes.

The reconstruction of the nipple-areola complex (NAC) is an aesthetically and psychosocial important final step in breast reconstruction. While numerous publications examine the long-term results using various techniques to reconstruct the nipple, to our knowledge there have been few studies on the long-term results after areolar reconstruction. The study therefore examines the long-term results after areola reconstruction in women with autologous breast reconstruction. In the period 2014-2016 we performed NAC reconstructions in 126 patients in our clinic. The areola was reconstructed by full skin transplantation from the groin or upper eyelids. A total of 27 women with a median age of 52 ± 8.6 years after a median period of 1.7 ± 0.7 years were examined with regard to colour change, size change and satisfaction with the reconstruction result of the MAK. The results showed a noticeable colour fading with good satisfaction of the patients with the result. We observed an increase in the size of the neoareoles by an average of 13,9 percent with full skin from the groin and 34,6 percent with full skin from the upper eyelids. Patients should be informed preoperatively of colour fading and size changes of the neo-areola.

Cerebral effects of resuscitation with either epinephrine or vasopressin in an animal model of hemorrhagic shock.

PURPOSE: The use of epinephrine (EN) or vasopressin (VP) in hemorrhagic shock is well established. Due to its specific neurovascular effects, VP might be superior in concern to brain tissue integrity. The aim of this study was to evaluate cerebral effects of either EN or VP resuscitation after hemorrhagic shock. METHODS: After shock induction fourteen pigs were randomly assigned to two treatment groups. After 60 min of shock, resuscitation with either EN or VP was performed. Hemodynamics, arterial blood gases as well as cerebral perfusion pressure (CPP) and brain tissue oxygenation (PtiO2) were recorded. Interstitial lactate, pyruvate, glycerol and glutamate were assessed by cerebral and subcutaneous microdialysis. Treatment-related effects were compared using one-way ANOVA with post hoc Bonferroni adjustment (p < 0.05) for repeated measures. RESULTS: Induction of hemorrhagic shock led to a significant (p < 0.05) decrease of mean arterial pressure (MAP), cardiac output (CO) and CPP. Administration of both VP and EN sufficiently restored MAP and CPP and maintained physiological PtiO2 levels. Brain tissue metabolism was not altered significantly during shock and subsequent treatment with VP or EN. Concerning the excess of glycerol and glutamate, we found a significant EN-related release in the subcutaneous tissue, while brain tissue values remained stable during EN treatment. VP treatment resulted in a non-significant increase of cerebral glycerol and glutamate. CONCLUSIONS: Both vasopressors were effective in restoring hemodynamics and CPP and in maintaining brain oxygenation. With regards to the cerebral metabolism, we cannot support beneficial effects of VP in this model of hemorrhagic shock.

[How well are patients informed on the websites of German university breast centres about the possibilities of breast reconstruction?] / Wie gut werden Patientinnen auf Internetseiten von deutschen universitären Brustzentren über die Möglichkeiten der Brustrekonstruktion informiert?

INTRODUCTION: In recent decades, the internet has become one of the most important sources of information for patients. How substantial are the possibilities to find out about breast reconstruction on the homepages of university hospitals in Germany? Is there information about plastic surgery with its spectrum of modern reconstructive possibilities? METHODS: A total of 35 homepages of university breast centres in Germany was analysed for the indication of cooperation with a plastic surgeon or a department for plastic surgery and their links, with information on reconstructive possibilities such as implant reconstruction, autologous soft tissue reconstruction with pedicled and free flaps as well as lipofilling. RESULTS: A plastic surgeon or a cooperating department is mentioned on 49 % of the homepages. Of those homepages, 20 % contain a direct link. 91 % of the homepages describe the possibility of breast reconstruction in general, 80 % of the websites the use of autologous tissue. In 51 % of the cases, a free tissue transfer is mentioned, whereas only 23 % describe the procedures like DIEP flap, TMG, or I-GAP in more detail. Only two centres use detailed illustrations. Six websites (17 %) describe reconstruction by pedicled TRAM flap only. Breast reconstruction with a silicone implant is mentioned on 71 % of the websites. The possibility of lipofilling is discussed in 31 %. DISCUSSION: About half of the websites of university breast centres do not show any cooperation with a plastic surgeon. There are significant gaps in the information on free tissue transfer for breast reconstruction.

Significant [C3a] increase in free flaps after prolonged ischemia.

BACKGROUND: Free tissue transfer (FTT) represents a clinical model to measure ischemia-reperfusion injury (IRI). This study was conducted to detect substances relevant for IRI after FTT. METHODS: Eighteen patients underwent lower leg reconstruction with free myocutaneous latissimus dorsi muscles and were monitored clinically and by microdialysis technique. Patients were retrospectively classified as group A (n = 12) (no prolonged IRI) or group B (n = 6) (prolonged IRI). One catheter was placed into the flap and one into the reference tissue. Samples were collected during ischemia and in 90 min steps after reperfusion. Biochemical substances (glucose, pyruvate, lactate, and glycerol) and immunological substances (interleukin 8 [IL-8], complement 3a [C3a], and regulated on activation normal T cell expressed and secreted [RANTES]) were then analyzed. RESULTS: All free myocutaneous latissimus dorsi flaps healed primarily. Minor complications included revisions of the microvascular anastomoses due to hematoma or thrombus formation and increased total flap ischemia time in group B significantly when compared to group A (P < 0.001). No significant differences of biochemical substance concentrations were detected during reperfusion in target and control tissue of both groups. IL-8 and C3a were at detectable levels, whereas the results for RANTES were inconsistent. Either for group A and group B, we found higher concentrations of C3a in target tissue compared with control tissue. Furthermore, during the first 90 min of reperfusion, we found a highly significant increase of C3a (P < 0.001) in the target tissue of patients with increased ischemia time. CONCLUSIONS: Given our results, C3a is a highly sensitive early indicator of ischemia-reperfusion damage. Our results give further insight into development of IRI after complicated FTT.

Functional recovery of chronic ischemic myocardium after surgical revascularization correlates with magnitude of oxidative metabolism.

BACKGROUND: The purpose of this study was to validate myocardial microdialysis measurements in patients after myocardial infarction with or without associated postoperative functional recovery in order to develop a highly sensitive tool for real-time in vivo detection of microcellular disorder during cardiac operations. METHODS: In 20 patients undergoing coronary artery bypass grafting, microdialysis catheters were implanted into scar or hibernating segments detected by means of magnetic resonance imaging, and into a vital area of the right ventricle (control). Myocardial glucose, lactate and pyruvate were analyzed perioperatively. Myocardial ethanol washout was measured as a sign of recovered local blood flow. RESULTS: After surgical revascularization, improvement of wall motion was found in all hibernating segments compared to the scar segments paralleling an increased glucose delivery to the tissue and increased myocardial tissue flow. The myocardial glucose/lactate ratio and pyruvate also showed significantly higher values. Microdialytic measurements of the viable segments were comparable with those of the right ventricle. CONCLUSIONS: Our results indicate that microdialysis measurements parallel magnetic resonance imaging findings in patients with revascularization of chronic ischemic myocardium with dyskinetic segments. The metabolism of those segments is characterized by a significantly increased tissue flow, an increased utilization of glucose and a better oxidative nutrition.

The metabolic and renal effects of adrenaline and milrinone in patients with myocardial dysfunction after coronary artery bypass grafting.

INTRODUCTION: Myocardial dysfunction necessitating inotropic support is a typical complication after on-pump cardiac surgery. This prospective, randomized pilot study analyzes the metabolic and renal effects of the inotropes adrenaline and milrinone in patients needing inotropic support after coronary artery bypass grafting (CABG). METHODS: During an 18-month period, 251 patients were screened for low cardiac output upon intensive care unit (ICU) admission after elective, isolated CABG surgery. Patients presenting with a cardiac index (CI) of less than 2.2 liters/minute per square meter upon ICU admission - despite adequate mean arterial (titrated with noradrenaline or sodium nitroprusside) and filling pressures - were randomly assigned to 14-hour treatment with adrenaline (n = 7) or milrinone (n = 11) to achieve a CI of greater than 3.0 liters/minute per square meter. Twenty patients not needing inotropes served as controls. Hemodynamics, plasma lactate, pyruvate, glucose, acid-base status, insulin requirements, the urinary excretion of alpha-1-microglobuline, and creatinine clearance were determined during the treatment period, and cystatin-C levels were determined up to 48 hours after surgery (follow-up period). RESULTS: After two to four hours after ICU admission, the target CI was achieved in both intervention groups and maintained during the observation period. Plasma lactate, pyruvate, the lactate/pyruvate ratio, plasma glucose, and insulin doses were higher (p < 0.05) in the adrenaline-treated patients than during milrinone or control conditions. The urinary excretion of alpha-1-microglobuline was higher in the adrenaline than in the control group 6 to 14 hours after admission (p < 0.05). No between-group differences were observed in creatinine clearance, whereas plasma cystatin-C levels were significantly higher in the adrenaline than in the milrinone or the control group after 48 hours (p < 0.05). CONCLUSION: This suggests that the use of adrenaline for the treatment of postoperative myocardial dysfunction - in contrast to treatment with the PDE-III inhibitor milrinone - is associated with unwarranted metabolic and renal effects.

[Adequate Antibiotic Prophylaxis and Therapy of Periprosthetic Infections of the Breast - Review of 468 Consecutive Implant Removals]. / Gezielte Antibiotika-Prophylaxe und Therapie periprothetischer Infektionen der Brust ­ Erfahrungen aus 468 konsekutiven Implantatentfernungen.

Background Periprosthetic infections are feared complications in aesthetic as well as in reconstructive breast surgery. The purpose of our study was to evaluate our institution's specific culture data and to identify most common organisms and suitable antibiotics for prophylaxis and first line treatment in implant-based breast surgery. Patients and Methods We analyzed all patients with a change or removal of breast implants in the period from 01.01.2012 to 31.12.2015 retrospectively. Based on the medical records, the surgical indications were identified and specifically analyzed for signs of infection and capsular fibrosis. In addition, we assessed all microbiological data of these interventions. Results 468 implant removals or exchanges were performed in 360 patients. Microbiological smears were gathered from 169 patients (249 implants). Bacteria were cultured from 23 implants (21 patients). In 6 additional implants (four patients) a periprosthetic infection was present, without pathogen detection. In most cases, advanced capsular fibrosis was the reason for implant exchange. In 17 smears bacterial detection was carried out despite absence of clinical signs of infection. In 17 cases coagulase-negative staphylococci were detected. In 4 Staphylococcus aureus, and once each E. coli, Morganella morganii and Proprionibacterium acnes (one double infection). All pathogens were sensitive to piperacillin/tazobactam and vancomycin. One resistancy was seen to cefuroxime and amoxicillin/clavulanic acid, and 2 to gentamicin, ciprofloxacin and clindamycin. Conclusion In the majority of cases, pathogen detection was an incidental finding, while capsular contracture caused surgical revision. Pathogens and resistance patterns found in this study differed from the majority of international publications. In our institution, Cefuroxime and amoxicillin/clavulanic acid have been proven to be a reasonable choice for prevention and treatment of periprosthetic infections. Especially in fulminant infections piperacillin/tazobactam would be our choice for initial treatment, until the specific antibiogram is available.

C3a levels and occurrence of subdermal vascular thrombosis are age-related in deep second-degree burn wounds.

BACKGROUND: After second-degree burns, thrombosis of the subdermal vascular plexus may occur, necessitating epifascial necrectomy instead of tangential excision to ensure split skin graft healing. Until now, no parameter has been obtained to explain this phenomenon. METHODS: Thirty-four patients with deep second-degree burn wounds were divided into 2 groups. In group 1, patients' age was < 60 years, in group 2, > 60 years. In each patient, 2 microdialysis catheters were introduced into subdermal tissue of deep second-degree thermal wounds immediately after admission. Another 2 catheters were introduced in control tissue. We measured biochemical parameters (lactate, glycerol and glucose) and complement 3a (C3a) until surgery was performed. The surgically removed tissue was examined histologically. RESULTS: In thermal wounds of both groups, glucose levels fell, but lactate and glycerol levels rose compared to healthy tissue. Within the first 24 hours after trauma, C3a levels were significant higher in both groups, compared with controls (P < .01). After 24 hours the levels in group 1 had fallen to nonsignificant values, while in group 2 these levels remained high until surgery was performed (P < .001). We found significantly more thrombotic blood vessels in deep dermal tissue of group 2 (P < .005). Abbreviated burn severity index score was comparable in both groups. CONCLUSIONS: C3a is continuously elevated in deep second-degree burned wounds in patients > 60 years. This finding may be related to the occurrence of significantly more thrombotic blood vessels in deep dermal tissue of elderly patients. Microdialysis therapy is a useful tool to measure metabolic and immunologic parameters in thermally damaged tissue.

Evaluation of myocardial metabolism with microdialysis during bypass surgery with cold blood- or Calafiore cardioplegia.

BACKGROUND: For the first time, microdialysis was used to investigate in vivo and online the myocardial metabolism during and after cardiac surgery in patients treated with two different methods of myocardial protection. METHODS: Thirty patients underwent standard CABG with one of two different methods of myocardial protection. The patients were randomised to receive either cold blood (COLD group) or warm modified Calafiore cardioplegia (WARM group). Microdialysis probes were implanted into the myocardium of left ventricular apical region of the heart. Cardioplegia was given antegrade only. Microdialysis measurements were performed at time intervals before, during and 24 h after cardiopulmonary bypass and analysed for glucose, lactate, pyruvate and glycerol. RESULTS: Myocardial lactate concentrations were significantly higher in the WARM group compared with that of the COLD group, while serum lactate was comparable. Glycerol was significantly higher at the end of the clamping time in the WARM group. At the same time the glucose-lactate ratio as a marker of nutritional disorder had significantly lower levels in the WARM group. The cumulative CK-MB release over 24 h was significantly higher in those hearts protected with warm blood. CONCLUSIONS: The oxidative stress measured was significantly higher in patients undergoing CABG using modified Calafiore cardioplegia, whereas the cold cardioplegia minimised the effects of aortic clamping. The results indicate that cold cardioplegia offers superior protection of the heart, in terms of more rapid normalisation of myocardial metabolism. In elective myocardial revascularisation, intermittent antegrade warm blood cardioplegia is a comparable safe method of myocardial protection. However, in patients referring to a long clamping time, advantages of cold cardioplegia for myocardial revascularisation may be magnified.

Microdialysis as a Part of Invasive Cerebral Monitoring During Porcine Septic Shock.

BACKGROUND: Metabolic changes in critically ill patients with endotoxin-induced septic shock are measured primarily by techniques that afford organ-specific metabolic monitoring based on interstitial fluid samples. The present study was designed to evaluate the role of cerebral microdialysis (MD) as a part of invasive neuromonitoring during endotoxemia in a porcine model. MATERIALS AND METHODS: Continuous endotoxin infusion was administered to 7 female pigs and, in addition to hemodynamic monitoring and blood chemistry, interstitial lactate, pyruvate, glucose and glycerol concentrations in muscle, liver, and cerebral tissue were measured via in vivo MD for an observation period of 180 minutes. RESULTS: The cerebral concentrations of lactate and glycerol showed no significant increases, whereas the hepatic and muscular levels rose dramatically under endotoxemia. However, the lactate/pyruvate ratio and especially the lactate/glucose ratio showed a profound and significant increase in brain tissue as well. Cerebral perfusion pressure decreased from 77 to 50 mm Hg without reaching pathologic values. CONCLUSIONS: Although our results confirm the special protection of the brain during endotoxemia compared with other organs, early metabolic changes become evident by increasing lactate/pyruvate ratio and lactate/glucose ratio. MD appears to be a suitable additional technique in invasive neuromonitoring for obtaining early information about metabolic deterioration in the brain during septic shock.

Tissue metabolism during endotoxin shock after pretreatment with monophosphoryl lipid A.

OBJECTIVE: Preconditioning pigs with low doses of monophosphoryl lipid A (MPL), a non toxic derivate of lipid A, has been shown to induce endotoxin hyporesponsiveness and to reduce the metabolic and hemodynamic consequences of endotoxin shock. However, the mechanism is presently unclear. This study was designed to elucidate the effects of pretreatment with MPL on tissue metabolism in different organs by in vivo microdialysis of interstitial fluid. METHODS: In a controlled animal study at the university research laboratory, seven female mixed-breed pigs were exposed to an endotoxin infusion (1 microg/kg b.w. per h) after pretreatment with MPL in incremental doses of endotoxin during days 5-2 before the experiments. Seven animals receiving a saline pretreatment served as a control group. Hemodynamic variables and blood gas analyses including blood lactate were determined every 30 min until the animals died. Interstitial lactate and glycerol levels were measured in muscle, subcutaneous tissue and liver using in vivo microdialysis. RESULTS: Survival time was significantly prolonged after MPL preconditioning (8.95 (7.5-9.1) h vs. 5.35 (5.0-5.6) h, P<0.05). Hemodynamic parameters were not significantly different between the treatment and control groups, while mixed venous saturation (81% (70-93%) vs. 30% (22-48%)) and arterial blood pH (7.39 (7.33-7.44) vs. 7.21 (7.1-7.25)) and pO(2) were significantly higher in the preconditioned group (P<0.05). The interstitial concentrations of lactate and glycerol in all investigated tissues were significantly higher in control animals than the those who had been pretreated with MPL (P<0.05). CONCLUSIONS: Preconditioning with low doses of monosphosphoryl lipid A attenuates the negative effects of endotoxemia on tissue metabolism, probably by reducing O(2)-consumption. These changes may be subtle and, hence, only fully detectable by monitoring tissue metabolism.

Myocardial redox state during coronary artery bypass grafting assessed with microdialysis.

PURPOSE: Microdialysis allows the biochemical analysis of interstitial fluids of nearly every organ as a bedside procedure. This technique could be useful to reveal data about the myocardial metabolism during cardiopulmonary bypass in human coronary artery bypass graft (CABG) surgery. METHODS: In 17 patients undergoing CABG a myocardial microdialysis catheter (CMA 70, CMA/Microdialysis AB, Sweden) was inserted in the apical region of the beating heart. Microdialysis measurements were performed at timed intervals before, during, and after cardiopulmonary bypass (CPB). The concentrations of lactate and pyruvate were analyzed semi-continuously. RESULTS: During CPB the myocardial lactate-pyruvate-ratio (LPR) rose from an initial 11 (8-15) to 33 (29-41) ( P<0.01). After CPB the LPR decreased to 4 (3-7) at the end of observation ( P<0.05). The pyruvate concentration showed an immediate increase from 34 (30-42) microM at the end of CPB to 181 (147-234) microM after removal of the cross-clamp with subsequent increase during reperfusion ( P<0.01). Plasma lactate and pyruvate showed no essential changes during the study. CONCLUSION: Using the microdialysis technique it was possible to analyze myocardial metabolic changes during CABG. The course of myocardial LPR as a sensitive indicator of the myocardial redox state showed profound changes during and after CPB. We propose the microdialysis technique as an additional monitoring tool in CABG.

Effects of tilting and volume loading on plasma levels and urinary excretion of relaxin, NT-pro-ANP, and NT-pro-BNP in male volunteers.

The polypeptide relaxin (RLX) has been suggested to play a role in cardiorenal integration and to be related to the natriuretic peptide system. We hence examined the effects of variations in thoracic blood volume and intravenous volume loading on plasma and urinary RLX levels and associated changes in natriuretic peptide levels in healthy men. Two groups of eight subjects were randomly tilted into a 15 degrees feet-down or a 15 degrees head-down position. Ten volunteers were crossover subjected to an infusion of 15 ml/kg of 0.9% NaCl (over 60 min) or control during an observation period of 10 h. Blood and urine were sampled at timed intervals. RLX, NH(2)-terminal prohormones of atrial natriuretic peptide (NT-pro-ANP), and NH(2)-terminal prohormones of brain natriuretic peptide (NT-pro-BNP) were determined by enzyme, radio-, and electrochemoluminescence immunoassays, respectively. NT-pro-ANP levels (in percentage of baseline levels) were higher (P < 0.05) during the head-down (124 +/- 13%) than during the feet-down position (82 +/- 6%). NT-pro-BNP and RLX were not affected by tilting. Volume loading induced a short-lasting increase in plasma NT-pro-ANP, a delayed increase in plasma NT-pro-BNP, had no effect on plasma RLX, and induced a parallel increase in urine flow, renal excretion of sodium, RLX, and NT-pro-BNP. It is concluded that variations in thoracic blood volume in healthy men are not associated with variations in plasma RLX. Increased urinary RLX and NT-pro-BNP excretion during volume loading suggest renal production and a possible role of kidney-derived RLX and brain natriuretic peptide in sodium homeostasis in men.

The relationship between urotensin II plasma immunoreactivity and left ventricular filling pressures in coronary artery disease.

The role of urotensin II (U-II)--a vasoactive, mitogenic, and inotropic, peptide--in the pathophysiology of heart failure is controversial. The present study explores the relationship between plasma U-II immunoreactivity (U-IIIR) and hemodynamics in patients with coronary artery disease (CAD). Thirty-six patients with CAD-3 undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) and 36 medical patients (MED group) with CAD-1 to CAD-3 during right heart catheterization were studied. Significant correlations were observed between pulmonary capillary wedge pressure (PCWP) and U-IIIR--determined by enzyme immunoassay (EIA)--before (rho = 0.83) and after (rho = 0.6) cardiopulmonary bypass in the CABG group. With the exception of the CPB period, CABG patients with increased PCWP before CPB had higher U-II(IR) concentrations throughout the procedure. Significant correlations were observed between U-IIIR, proANP, proBNP, and mean right ventricular pressure (RVPM) in MED patients. No correlation was detectable between U-IIIR and PCWP. However, MED patients with CAD-3 (n = 13) had higher levels of U-IIIR, NTproANPIR (RIA), NTproBNPIR (EIA) and higher cardiac filling pressures than patients with CAD-1 (n = 13). These findings support an association between plasma U-IIIR levels and diastolic myocardial dysfunction in ischemic heart failure. The discrepancies regarding left and right cardiac filling pressures and U-IIIR levels in CABG and MED patients require further evaluation.