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Biomedical subjects

F Bach

Publications and source records attributed to F Bach.

At least 19 recordsLinked to original sources
PubMed2006

Angiopoietins in malignancy.

BACKGROUND: Tumour growth is dependant upon the development of an adequate blood supply. This, in turn, is thought to depend upon a switch by the tumour, from a dormant to angiogenic state. Recent data suggest that this switch may occur when the balance of pro- and anti-angiogenic agents alters to promote angiogenesis. Angiopoietins may be involved in this balance. METHODS: An electronic literature search was performed with respect to angiopoietins from 1996 to the present. Published data from in-vitro and in-vivo studies were critically analysed. A specific focus was made of studies relating to tumour growth and vasculature. RESULTS: Since angiopoietin-1 was first described in 1996, three more angiopoietins have been described. All family members bind to the Tie-2 receptor. There is now a considerable accumulation of data that suggests they play a pivotal role in the development and stabilisation of tumour vasculature. angiopoietin-2 appears to be pro-angiogenic whilst angiopoietin-1 appears to be a stabilising factor. CONCLUSIONS: Recent trials of anti-angiogenic agents show promise in the treatment of solid human cancers. The angiopoietins are a new family of proteins that appear to be influential in the development of the tumour vasculature. Manipulation of the angiopoietin balance may provide a potential therapeutic target in human cancer.

Angiopoietins↗
PubMed2003

[Acquired hemophilia A as a cause of postoperative bleeding].

Acquired spontaneous hemophilia is a rare but potentially life-threatening disease, which poses a major challenge to intensive care medicine. We report a case in which the disease occurred postoperatively in a patient following uncomplicated lumbal discectomy. The clinical sequelae involved hemorrhagic shock (cHb 4.1 g/dl; hct 17 %; systolic BP 60 mmHg; HR 130/min; saO2 73 %) due to retroperitoneal hematoma eight days after neurosurgical intervention. While lesions of the retroperitoneal vessels were not found during emergent angiography and laparotomy, the laboratory results showed a slightly prolonged activated prothrombin time (aPTT; 47 s). However, application of fresh frozen plasma (FFP) even prolonged the aPTT (53 s). Analysis of clotting factors proved a deficiency of factor VIII with a reduced activity of about 20 %, which was resistant against therapy with desmopressin (DDAVP) and substitution of factor VIII. Thus, the plasma-mix-test was performed, showing complete inactivation of the factor VIII-activity of the pooled plasma. This evidenced the presence of acquired inhibitors against factor VIII. Hemostasis was successfully and immediately restored with the application of recombinant factor VIIa (rFVIIa), including boluses of 60 - 80 microg/kg every 6th - 8th hour (supplemented with tranexamic acid, 3 x 1 g/d), leading to a continuous infusion of 12 microg/kg per hour. With prednisolone (1 mg/kgBW/d) over the ensuing 8 weeks, the antibodies were sufficiently suppressed and no additional substitution of factor VIII was necessary to maintain normal hemostasis.

Blood Coagulation Tests↗
PubMed2002

Modulation of the inflammatory response to cardiopulmonary bypass by dopexamine and epidural anesthesia.

BACKGROUND: Cardiopulmonary bypass (CPB) induces a systemic inflammatory reaction. Microcirculation-dependent alteration of the gut mucosal barrier with subsequent translocation of endotoxins is a postulated mechanism for this inflammatory response. This study was designed to elucidate whether two different approaches to modulate splanchnic perfusion may influence systemic inflammation to CPB. METHODS: We examined 40 patients scheduled for elective coronary bypass surgery in a prospective, randomized study. One group (DPX) received dopexamine (1 micro g. kg-1. min-1) continuously after induction of anesthesia until 18 h after CPB. The control group (CON) received equal volumes of NaCl 0.9% in a time-matched fashion. In a third group (EPI) a continuous epidural infusion of bupivacaine 0.25% [(body height (cm) - 100). 10-1=ml.h-1] was administered for the whole study period. Procalcitonin (PCT), tumor necrosis factor (TNF-alpha), soluble TNF receptor, human soluble intercellular adhesion molecule-1, C-reactive protein (CRP) and leukocyte count were measured as parameters of inflammation. RESULTS: All parameters significantly increased following CPB. Increases of PCT, TNF-alpha and leukocyte count were significantly attenuated in the DPX and EPI groups at different time points. However, neither splanchnic blood flow nor oxygen delivery and consumption were different when compared with the CON-group. CONCLUSION: These results do suggest that mechanisms other than an improved splanchnic blood flow by DPX and EPI treatment have to be considered for the anti-inflammatory effects.

Aged↗
PubMed2001

Recovery profile and side effects of remifentanil-based anaesthesia with desflurane or propofol for laparoscopic cholecystectomy.

BACKGROUND: Nitrous oxide (N2O) has been suggested to contribute to bowel distension, resulting in worsened operating conditions for laparoscopic surgery, and to increase incidence of postoperative nausea and vomiting. Therefore, our objective was to assess the feasibility of two remifentanil-based anaesthetic regimens free from N2O with special regard to recovery profile, postoperative analgesic demand and side effects in patients undergoing laparoscopic cholecystectomy. METHODS: Fifty patients (ASA I-II, 23-65 yr) were randomly assigned to receive remifentanil-based anaesthesia in conjunction with propofol (group R/P) or desflurane (group R/D). After standardised induction of anaesthesia, analgesia was continued with remifentanil in all patients. For maintenance of hypnosis, propofol or desflurane were used in concentrations to ensure loss of consciousness, lack of awareness, and maintenance of heart rate and blood pressure within +/- 25% of initial values. At the end of surgery all anaesthetics were discontinued without tapering and early emergence and recovery were recorded. Pain scores were assessed by using a visual analogue scale. Patient-controlled analgesia with i.v. piritramide was used for treatment of postoperative pain and recorded for 90 min in the postanaesthesia care unit (PACU). In addition, side effects were noted. RESULTS: Early emergence from anaesthesia did not differ between the groups. In group R/P, time to eye opening, spontaneous respiration and extubation was 4.4 +/- 2.9 min, 5.2 +/- 3.4 min and 5.5 +/- 3.3 min respectively, compared with 4.7 +/- 2.7 min, 5.3 +/- 2.4 min and 5.7 +/- 2.5 min in group R/D. While pain scores did not differ between both groups on admission to the PACU, patients receiving desflurane required more i.v. piritramide as compared to those receiving propofol, 22.0 +/- 6.5 mg and 17.9 +/- 7.0 mg, respectively (P<0.05). Nausea was less frequent after propofol (16% vs. 48%, P<0.05). CONCLUSION: In patients undergoing laparoscopic cholecystectomy, remifentanil-based anaesthetic regimens in conjunction with propofol or desflurane are suitable and allow for rapid recovery from anaesthesia. However, the use of propofol results in less postoperative analgesic consumption and nausea as compared to desflurane.

Adult↗
PubMed2001

Anticoagulation during cardiopulmonary bypass in patients with heparin-induced thrombocytopenia type II and renal impairment using heparin and the platelet glycoprotein IIb-IIIa antagonist tirofiban.

BACKGROUND: Patients with heparin-induced thrombocytopenia type II require an alternative to standard heparin anticoagulation. However, in patients with renal impairment, anticoagulation during cardiopulmonary bypass with agents such as danaparoid sodium or r-hirudin are associated with hemorrhage. Anticoagulation with unfractionated heparins combined with prostacyclin, a potent platelet aggregation inhibitor, is associated with severe hypotension. The authors investigated a new concept using unfractionated heparins after platelet inhibition with the short-acting platelet glycoprotein IIb-IIIa antagonist tirofiban. METHODS: Ten patients with heparin-induced thrombocytopenia type II and renal impairment were enrolled in the investigation. All had heparin-induced thrombocytopenia type II antibodies present as proved by the heparin-induced platelet aggregation assay, the heparin-platelet factor 4 enzyme-linked immunosorbent assay, or both. In all patients, preoperative anticoagulation to an activated partial thromboplastin time of 40-60 s was performed with r-hirudin. Anticoagulation during cardiopulmonary bypass was achieved with a bolus of 400 IU/kg unfractionated heparins after a bolus of tirofiban 10 microg/kg followed by an infusion of tirofiban at a rate of 0.15 microg x kg(-1) x min(-1) until 1 h before conclusion of cardiopulmonary bypass. Additional unfractionated heparins were only administered if activated clotting time decreased below 480 s. Coagulation was monitored by a abciximab-modified TEG and the adenosine diphosphate-stimulated (20 microm) platelet aggregometry. D-dimer concentrations, as a marker of venous thromboembolism, were measured before and 12, 24, and 48 h after surgery. Postoperative antithrombotic therapy was started immediately with r-hirudin to anticoagulation to an activated partial thromboplastin time of 40-60 s. RESULTS: The postoperative blood loss ranged from 110 to 520 ml. No patient needed reexploration. In no patient was there clinical evidence of thrombosis or embolism in the postoperative period or of a critical increase of the D-dimer concentrations, suggesting venous thromboembolism. Transfusion of platelets was necessary in only two patients. CONCLUSIONS: The protocol is easy to perform and no increased postoperative bleeding and no thromboembolic complications occurred. The combination of unfractionated heparins and tirofiban may be an alternative to other anticoagulation strategies in patients with heparin-induced thrombocytopenia.

Adult↗
PubMed2000

[Fulminant pulmonary embolism after cesarean section].

On the first day after an uneventful emergence caesarean section a 36-year-old woman developed circulatory collapse requiring cardiopulmonary resuscitation for 15 minutes. After resuscitation the patient remained haemodynamically unstable and was clinically highly suspected to suffer from fulminant pulmonary embolism. In this situation the physicians caring for the patient decided to perform a surgical pulmonary embolectomy without previous diagnostic workup. Massive emboli were removed from both pulmonary arteries. Postoperatively the patient recovered and was transferred to a rehabilitation center without severe cerebral sequelae.

Aged↗
PubMed1999

[Bioavailability of sotalol in short bowel syndrome].

BACKGROUND: The individual bioavailability of enterally administered drugs is usually uncertain in case of reduced bowel length. Routine measurements of plasma concentrations are available only for a small number of drugs. The daily dose recommended by the manufacturers may result in subtherapeutic plasma concentrations when given to such patients. CASE REPORT: In 2 patients with hemodynamically relevant atrial fibrillation and reduced gut length application of increasing sotalol doses was initiated. For the assessment of the individual bioavailability plasma concentrations were measured via HPLC immediately before and 2 hours after enteral application of sotalol. Judging by clinical criteria both patients were treated successfully. Even in the patient with severe short bowel syndrome (stomach, duodenum and 50 cm jejunal remnant) doubling of the daily dose led to a substantial increase in plasma concentrations. CONCLUSION: Effective enteral medication with sotalol in patients with short residual bowel is possible. Normal plasma concentrations can be achieved by administering doses according to the manufacturers' instructions. In case of severe short bowel syndrome, the measurements of plasma concentrations may be beneficial in supervising dose-adjustment.

Aged↗
PubMed1999

[Procalcitonin after extracorporeal circulation. Synthesis in the hepatosplanchnic region].

UNLABELLED: Procalcitonin (PCT) is an inflammatory peptide of still unknown origin. In this study we investigated a potential source for circulating PCT in patients undergoing coronary artery bypass grafting. METHODS: To determine PCT concentrations, arterial, liver-venous and mixed-venous blood samples were collected time matched perioperatively in 20 patients scheduled for cardiac surgery using cardiopulmonary bypass (CPB). RESULTS: PCT concentrations significantly increased 4 hours postoperatively compared to baseline values (0.74 +/- 0.45 vs. 0.16 +/- 0.04 ng/ml). The highest concentrations were measured 18 hours postoperatively (1.44 +/- 1.01 ng/ml). PCT concentrations in liver venous samples were significantly higher (1.67 +/- 1.29 ng/ml) than in time matched collected arterial samples (1.44 +/- 1.01 ng/ml). CONCLUSION: These results provide evidence, that hepatosplanchnicus is a source for PCT synthesis in patients following CPB. The mechanism of PCT induction remains unclear. A loss of gut mucosal barrier function with translocation of endotoxins and the inflammatory response with release of cytokines following cardiopulmonary bypass has to be discussed.

Calcitonin↗