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Biomedical subjects

G Ziemer

Publications and source records attributed to G Ziemer.

At least 19 recordsLinked to original sources
PubMed2001

Correction of anterior thoracic wall deformities: improved planning by means of 3D-spiral-computed tomography.

Surgical correction of anterior thoracic wall deformities is an extensive procedure with considerable operative trauma. The procedure can be markedly supported by means of preoperative 3D spiral-computed tomography for the purpose of improved preoperative planning in order to avoid unnecessary tissue mobilization. It is also helpful to enhance the patients' comprehension regarding the operative requirements.

Adolescent↗
PubMed2000

S-100 after correction of congenital heart defects in neonates: is it a reliable marker for cerebral damage?

BACKGROUND: Newborns undergoing cardiac operation may acquire some extent of neuronal damage. An early diagnosis is especially hard regarding neonates. In the past years, S-100 has been widely discussed as a marker revealing perioperative damage to the brain. METHODS: Sequential blood samples from 33 neonates undergoing repair of congenital heart disease were taken perioperatively. Samples of 12 healthy neonates were taken at birth as a control group. The newborns were divided into four groups: cyanotic and acyanotic disease operated on in deep hypothermic circulatory arrest, operation without deep hypothermic cardiac arrest, and operation without extracorporeal circulation. RESULTS: Even in healthy neonates, serum S-100 levels were at 10-fold values compared with adults. On admission, S-100 values in the operative groups were similar. During extracorporeal circulation, levels rose to a certain degree. Cyanotic newborns operated on in deep hypothermic cardiac arrest had significantly higher S-100 levels compared with acyanotic newborns also operated on in deep hypothermic cardiac arrest (p < 0.001). Two newborns who experienced seizures postoperatively had the highest absolute S-100 levels. One child with a poor neurologic outcome but no seizures did not have different values when compared with her group. CONCLUSIONS: In this study, S-100 seemed to be a possible marker for a certain degree of neurologic deficit after cardiac operation in neonates, especially regarding postoperative seizures. The missing peaks of this protein in one newborn with poor neurologic outcome show that it is not possible to exclude damage to the brain with normal postoperative values. These results suggest that the mechanism of cerebral damage and S-100 release into the blood in neonates with a developing central nervous system and blood-brain barrier is not fully understood.

Adult↗
PubMed2000

Successful weaning of a transplanted heart from biventricular assist device.

Exceptionally few cases worldwide have survived weaning from a biventricular assist device following heart transplantation in contrast to those who underwent early retransplantation. We present a successful outcome after biventricular assist device implantation following initial biventricular failure after heart transplantation. Weaning could be performed after 1 week, although pulmonary vascular resistance remained markedly elevated.

Adult↗
PubMed2000

A patient with five primary tumours of the aerodigestive tract and the kidney. The Interdisciplinary Tumour Board, Tübingen.

We report the case of a 65-year-old male who developed an oropharyngeal carcinoma, an oesophageal carcinoma and two primary bronchial carcinomas in combination with a renal cell carcinoma as an additional primary entity. By means of an aggressive diagnostic regimen including radiological and nuclear imaging techniques all carcinomas were detected early and could be treated with curative intention.

Bronchial Neoplasms↗
PubMed2000

[Pulsed spray lysis with reteplase in peripheral arterial occlusions--technique and initial results].

PURPOSE: Urokinase followed by rt-PA are the most frequently used drugs approved for thrombolysis in peripheral arteries in the USA and Europe. We wanted to test the safety and efficacy of low-dose reteplase administered by pulsed spray technique. MATERIALS AND METHODS: 10 patients with acute or subacute occlusion of a peripheral artery (n = 8) or graft (n = 2) were treated (history 8 +/- 17 days; occlusion length 4-60 cm, mean 23 cm). Reteplase was administered as an intra-arterial (i.a.) bolus (0.5 U/10 cm of occlusion length) followed by pulsed spray lysis (1 U/h for the first 2 h, then 0.5 U/h). The catheter was placed into the occlusion. In addition the patients received heparin (i.a.) and aspirin (oral). The site of puncture was closed with a percutaneous suturing system prior to discontinuation of heparin treatment. RESULTS: A total dose of 3.3 +/- 1.2 U reteplase was administered. The primary success rate was 7/10. Two distal embolizations and two bleeding complications were observed (one minor bleeding at the site of puncture and one rupture of the suture which had to be treated surgically). CONCLUSION: With regard to our limited data, low-dose i.a. reteplase seems to be safe and effective. Two bleeding complications were observed which both occurred at the site of puncture. Discontinuation of heparin treatment prior to sheath removal is recommended. Fibrinolysis with reteplase may be an alternative to urokinase or rt-PA.

Aged↗
PubMed2000

Evaluation of protein S-100 serum concentrations in healthy newborns and seven newborns with perinatal acidosis.

UNLABELLED: We measured Protein S-100 serum levels in 66 healthy newborns during the first week of life and in 7 newborns with perinatal acidosis. Normal values (n = 66) constantly ranged between 0.66 and 3.33 microg/l (2.5 and 97.5 percentiles) during the evaluation period. CONCLUSIONS: Newborns with signs of hypoxic-ischaemic encephalopathy (HIE) after perinatal acidosis showed elevated Protein S-100 serum levels, whereas newborns without these signs had normal concentrations. S-100 might thus be a marker of central nervous system damage in newborns. Key words: Asphyxia, brain damage, neonate

Acidosis↗
PubMed2000

The significance of preformed aprotinin-specific antibodies in cardiosurgical patients.

UNLABELLED: Acute hypersensitivity reactions are serious complications of reexposure to aprotinin. Previous contact via infusions or fibrin tissue adhesives can induce specific antibodies. In this study, we aimed to elucidate the preoperative prevalence of aprotinin-specific antibodies in patients scheduled for cardiac operations. Sera of 520 consecutive cardiosurgical patients were collected preoperatively and screened retrospectively for aprotinin-specific IgG using a standard enzyme-linked immunosorbent assay (ELISA). Positive sera were analyzed also for aprotinin-specific IgA (ELISA) and IgE (fluorescence enzyme immunoassay). The histories of all patients were reviewed with focus on aprotinin preexposure. Of 520 patients, 22 (4%) had specific IgG. Only three of these had a documented aprotinin preexposure. Of 448 patients exposed to aprotinin intraoperatively, 15 had preformed specific antibodies. The only patient presenting with severe anaphylaxis was positive for both IgG and IgE, and had a recent IV preexposure in cardiovascular surgery. The presence of aprotinin-specific IgG alone seems not to induce adverse reactions on exposure. Exposure history alone is not sensitive enough to identify patients with aprotinin-specific antibodies. IMPLICATIONS: Anaphylaxis on IV reexposure to aprotinin is a medical emergency. The clinical significance of preformed aprotinin-specific IgG remains questionable, whereas preformed IgE was present in the only patient who suffered from severe anaphylaxis on reexposure to aprotinin. Preformed antibodies are not reliably predicted by exposure history.

Aged↗
PubMed2000

Quality assessment of heparin coatings by their binding capacities of coagulation and complement enzymes.

In vitro testing of blood contacting materials before clinical application is generally advisable. Four heparin coatings from different manufacturers were tested for adsorbed proteins and soluble activation markers. The surface with the highest antithrombin, thrombin, high-molecular-weight-kininogen (HMWK) and the lowest fibrinogen binding capacity (Carmeda, Medtronic) showed significantly lower levels of granulocytes and platelet activation (beta-TG, PMN-elastase release). No statistically significant differences in soluble markers of the coagulation system could be detected (F1 + 2, TAT). Interestingly, complement activation (TCC) was significantly reduced within the group of the lowest adsorption of the complement factor C3. Our data demonstrate that there is a relation between the binding affinity of proteins (C1-inhibitor, C3-complement) and the consecutive changes in complement activation (TCC). Therefore, measuring adsorbed proteins on artificial surfaces is a suitable, sensitive and very reproducible method for assessing the thrombogenicity of biomaterials.

Adsorption↗
PubMed2000

[Comparative studies of the adsorption behavior of plasma proteins to heparin-coated surfaces].

Over the past 10 years, investigations have shown that heparin coating optimizes haemocompatibility in extracorporeal circulation systems. To date, however, the mechanisms involved have not been identified. 20 ml of fresh human blood were circulated in an in vitro closed-loop model with and without heparin coating. Using a newly developed ELISA, a quantitative analysis of the adsorbed plasma proteins was done. In addition, changes in coagulation, complement and blood cell releasing factors were measured by ELISA methods: prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin-III complex (TAT), PMN-elastase, beta-thromboglobulin (beta-TG) and terminal complement-complex (TCC). In uncoated tubing, high concentrations of fibrinogen, fibronectin, prothrombin, vitronectin, alpha 2-macroglobulin, von Willebrand factor and complement factor C3 were found. Large amounts of antithrombin-III, HMWK and C1-esterase inhibitor were found on the heparinized surfaces. In addition, the concentrations of the soluble plasma protein markers F1 + 2, FPA, PMN-elastase, TCC and beta-TG were significantly lower (p < 0.05) in the presence of heparin coating. The haemocompatibility of "foreign" surfaces depends largely on the extent to which the processes of activation and inhibition of humoral and cellular mediators permanently occurring at the natural endothelium can be simulated. Owing to the low adsorption of procoagulatory and proinflammatory enzymes, heparin-coated surfaces demonstrate significantly improved haemocompatibility.

Adsorption↗
PubMed2000

Repeated delayed sternal closure with stenting for right and left heart failure.

Delayed sternal closure is an established method to overcome circulatory instability, especially in pediatric cardiac surgery. We describe the management of complications in a seven-year-old boy in whom staged chest closure augmented by sternal stenting was used twice within three weeks, once for right heart and once for left heart failure.

Cardiac Output, Low↗
PubMed1999

Increased coagulation and bradykinin-release in shed pleural blood during cardiac surgery.

Retransfusion of shed pleural blood is generally believed to contribute to a decrease of intraoperative blood requirements, however, hemodynamic or hemostatic side effects are nevertheless still controversial. Some 13 patients (age: 58 +/- 11) undergoing CPB surgery including the use of the internal mammaria artery (IMA) were investigated. For IMA preparation, pleura of the left hemithorax was opened, allowing blood to accumulate within the pleural cavity. Some 472 +/- 258 ml blood volumes were retransfused after 79 +/- 11 min clamp time. After 50 +/- 15 s, mean arterial blood pressure (AP) dropped from 68 +/- 15 to 36 +/- 8 mm Hg, and the calculated systemic vascular resistance (SVR) decreased from 1124 +/- 263 to 596 +/- 153 dyn s(-1) cm5 (p < 0.01). Bradykinin levels in the retransfused shed blood showed significantly higher values (205 +/- 88 fmol/ml) compared to the systemic blood (24 +/- 19 fmol/ml). Thrombin-antithrombin-III complexes were strongly elevated in the shed pleural blood, and after retransfusion the systemic blood values increased significantly. After retransfusion of shed pleural blood during CPB an acute drop in AP and SVR occurred, probably caused by high bradykinin concentrations. We therefore recommend that the accumulation of shed blood is avoided by continuous retransfusion as is now the standard procedure in our University hospital.

Blood Coagulation Disorders↗
PubMed1999

Resection of a large right atrial hemangioma in a neonate after prenatal diagnosis.

Cardiac hemangiomas are extremely rare benign tumors. We describe the case of a right atrial hemangioma in a neonate diagnosed prenatally and successfully operated 10 days after spontaneous delivery. This unusual case illustrates the importance of prenatal diagnosis and delivery of the baby next to a pediatric center with a department of appropriately specialized cardiovascular surgery.

Female↗
PubMed1999

Preparatory surgical stent placement facilitating extracardiac vascular connections.

Native pericardium can be valuable material for the construction of extracardiac vascular connections. To avoid its scarring by adhesions and to preform future vascular connections, ringed polytetrafluoroethylene prostheses were implanted into the pericardial sac during staged operations for univentricular heart disease. At reoperation, extracardiac connections were found to be greatly facilitated by this approach.

Anastomosis, Surgical↗
PubMed1999

Aprotinin in fibrin tissue adhesives induces specific antibody response and increases antibody response of high-dose intravenous application.

BACKGROUND: In cardiac operations, aprotinin therapy is used either locally as a component of commercially available fibrin tissue adhesives, intravenously, or combined. Our aim was to examine the formation of aprotinin-specific antibodies with regard to the application mode. METHODS: Sera of 150 patients who had undergone cardiac operations and were receiving aprotinin therapy for the first time were sampled before the operation and at medians of 3.5 and 13.3 months after the operation. Aprotinin-specific IgG including all subgroups and aprotinin-specific IgE were analyzed. Aprotinin was given locally (as contained in fibrin sealant; n = 45; median dose, 6000 KIU), intravenously (n = 46; 2.000 x 10(6) KIU), and combined (n = 59; 2.012 x 10(6) KIU). RESULTS: At 3.5 months, the prevalence of aprotinin-specific IgG antibodies was 33% (15/45 patients) after local, 28% (13/46 patients) after intravenous, and 69% (41/59 patients) after combined exposure (P =.0001). At 13.3 months, the prevalence of aprotinin-specific IgG antibodies was 10% (4/41 patients) after local, 31% (13/42 patients) after intravenous, and 49% (28/57 patients) after combined exposure. Total aprotinin dose was similar in patients who were antibody positive and negative. Before the operation, no aprotinin-specific antibodies were detected. Aprotinin-specific IgE were not found after the operation. CONCLUSION: Local aprotinin contact induces a specific immune response and reinforces that of intravenous exposure. The antibody spectrum is identical to the immune response induced by intravenous exposure. Any exposure should be documented. For use in cardiac operations as a hemostyptic, the necessity itself and alternatives for aprotinin as a stabilizing agent merit consideration.

Antibody Formation↗
PubMed1999

Increased adsorption of high molecular weight kininogen to heparin-coated artificial surfaces and correlation to hemocompatibility.

During the past 10 years investigations have demonstrated that heparin-coated devices used for extracorporeal circuits show an improved hemocompatibility. We investigated the pathway of adsorption of plasma proteins at heparin-coated artificial surfaces and the further activation of the humoral and cellular defense mechanisms of the blood. Twenty milliliters of fresh human blood (1 IU heparin/ml) filled a 50 cm long tubes (with and without covalent heparin-coating), prepared as an in vitro "Closed-Loop" model and recirculated at a temperature of 37 degrees C. After 5, 15, 30, 60 and 120 min fibrinogen and high molecular weight kininogen (HMWK) adsorption was measured by a newly developed modified ELISA technique. In addition, changes in coagulation and platelet activation were measured by well established assays. High concentrations of fibrinogen were detected after very short blood material contact, both on uncoated as well as heparin-coated tubes. However, high amounts of HMWK were only found on the heparin-bonded surfaces. In addition, the concentrations of the soluble coagulation marker prothrombin fragment F1+2 and the marker for platelet activation beta-thromboglobulin were significantly higher in the non-coated tubes. We presume that adsorption of HMWK to heparin-coated surfaces contributes to the improved hemocompatibility of these bondings.

Adsorption↗
PubMed1999

Transmyocardial laser revascularization in the acute ischaemic heart: no improvement of acute myocardial perfusion or prevention of myocardial infarction.

OBJECTIVE: Transmyocardial laser revascularization (TMLR) has been used to provide enhanced myocardial perfusion in patients not suitable for coronary revascularization or angioplasty. This study investigates the acute changes in myocardial perfusion after TMLR with a Holmium:Yttrium-Aluminium-Garnet (YAG) laser with a thermal imaging camera in a model of acute ischaemia, and confirms its midterm effects by post-mortem investigation of magnetic resonance imaging and histopathological examination. METHODS: Acute myocardial ischaemia was induced by occlusion of the dominant diagonal branch in ten sheep. Perfusion measurements were undertaken first in the unaffected myocardium, then after temporary occlusion of the coronary to obtain a control measurement for ischaemic myocardium. Myocardial perfusion was then evaluated during reperfusion after release of coronary occlusion. Then the coronary was permanently occluded and 20.5+/-2 channels were drilled with the Holmium:YAG laser and perfusion was measured again. The other four sheep served as control with untreated ischaemia. All animals were sacrificed after 28 days following administration of gadolinium i.v. to serve as contrast medium for magnetic resonance tomography. The hearts were subjected to magnetic resonance tomography and histopathological examination. RESULTS: Intraoperative perfusion measurements revealed a decreased perfusion after temporary occlusion and an increased perfusion in reperfused myocardium. After TMLR, no improvement of myocardial perfusion above the ischaemic level could be shown. Magnetic resonance images could neither confirm patent laser channels nor viable myocardium within ischaemic areas. On histology no patent endocardial laser channel could be detected. The transmural features were myocardial infarct with scar tissue. CONCLUSIONS: In the presented sheep model with acute ischaemia, TMLR with a Holmium:YAG laser did not provide acute improvement of myocardial perfusion as assessed by a thermal imaging camera. This would suggest no direct contribution of newly created laser channels to myocardial perfusion. As chronic effects are concerned, no perfused laser channels could be identified by later magnetic resonance imaging or histology.

Animals↗