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Biomedical subjects

S Christiansen

Publications and source records attributed to S Christiansen.

At least 37 records · Page 2Linked to original sources
PubMed2000

Are patients with Werlhof's disease at increased risk for bleeding complications when undergoing cardiac surgery?

BACKGROUND: It is generally assumed, that patients with Werlhof's disease (WD) are at increased risk for bleeding complications when undergoing cardiac surgery with extracorporeal circulation. Therefore we performed this case control study to estimate the real risk for bleeding complications of these patients. METHODS: Between 05/95 and 07/98, ten patients with WD (eight males, two females) underwent cardiac surgery employing extracorporeal circulation (WD-group). Five of these patients with platelet counts below 80/nl were treated by immunoglobulins preoperatively. Each patient with WD was matched to five patients without WD (no-WD-group) using diagnosis, age, gender, ejection fraction, number of distal anastomosis and body-mass-index as matching criteria. RESULTS: Mean number of platelet counts were significant lower in the WD-group than in the no-WD-group despite a significant increase of platelet counts after immunoglobulin treatment (54/nl-->112/nl, P=0.018). On the day before, directly after and on the first day after surgery they were 141/nl vs. 215/nl (P=0.012), 75/nl vs. 147/nl (P=0.001) and 93/nl vs. 136/nl (P=0.009). Accordingly, patients of the WD-group received significantly more platelet concentrates than patients of the no-WD-group (mean number of platelet concentrates: 2.3 versus 0.7, P=0.007). Total drainage loss via the mediastinal chest tubes was almost identical (1197 ml in the no-WD-group and 1140 ml in the WD-group). One patient of each group suffered from a bleeding complication requiring reexploration. Three patients of the no-WD-group (6%) and one patient of the WD-group (10%) expired postoperatively unrelated to WD. CONCLUSIONS: Patients with WD may possibly undergo cardiac surgery without a markedly enhanced risk for bleeding complications despite a more than usual transfusion requirement and significantly lower platelet counts perioperatively.

Adult↗
PubMed2000

Diagnosis, treatment and outcome of patients with Askin-tumors.

Askin tumors are highly malignant small-round-cell tumors of the thoracopulmonary region, which occur rarely. Therefore, we report on our experiences with eight patients (5 male, 3 females), who were treated in our department between 11'94 and 10'97 (age: 9-40 years, mean age: 20.5 years). All Askin tumors were diagnosed by histological and immunohistochemical examinations as well as molecular genetic proof of characteristic translocations. In all patients, the tumor arose from the chest wall, infiltrating adjacent ribs and parts of the lung. At the time of first diagnosis, five patients did not reveal any metastases. One patient suffered from intrapulmonary metastases and two patients from an infiltration of the diaphragm and of adjacent vertebral bodies. Treatment consisted of a pre- and postoperative (radio-) chemotherapy according to the EVAIA protocol and a radical tumor resection in all patients. The postoperative course was uneventful in seven patients, one patient suffered from pneumonia after multiple wedge resections for intrapulmonary metastases. Four patients, in whom primary tumor resection was complete, are alive 14, 20, 35 and 84 months after first diagnosis - only one patient had to undergo a second operation for a local relapse 17 months after first diagnosis. The other 4 patients, who suffered from a very extensive primary tumor, expired 13, 17, 18 and 39 months after the diagnosis was made. Our data demonstrate that Askin tumors require an aggressive multimodality treatment consisting of pre- and postoperative chemotherapy, radical surgical resection and postoperative irradiation, which may be performed preoperatively in selected cases, too.

Adolescent↗
PubMed2000

Small thymomas and myasthenia gravis: a poorly understood association.

Myasthenia gravis (MG) is associated with about 20% of all patients with thymomas, but the occurrence in patients with small thymomas is rare. The pathogenetic relevance of these small thymomas for MG is poorly understood until now. We report on the clinical course of a 39-year-old female patient suffering from MG and undergoing thymectomy for a small thymoma and discuss the pathogenetic importance of small thymomas for MG.

Adult↗
PubMed2000

Changes in calcaneal trabecular bone structure after heart transplantation: an MR imaging study.

PURPOSE: To use high-spatial-resolution magnetic resonance (MR) imaging to analyze the trabecular bone structure of the calcaneus in patients before and after heart transplantation and to compare this technique with bone mineral density (BMD) measurement in predicting therapy-induced bone loss and vertebral fracture status. MATERIALS AND METHODS: High-spatial-resolution 1.5-T MR imaging of the calcaneus was performed in 40 men 11-120 months after heart transplantation, in 11 men before heart transplantation, and in 10 age-matched male volunteers. Sagittal and transverse T1-weighted spin-echo images with a voxel size of 0.195 x 0.195 x 1.000 mm were obtained, and structure measurements analogous to bone histomorphometric values were calculated. In addition, the BMD of the lumbar spine was determined in the transplant recipients pre- and postoperatively by using quantitative computed tomography, and vertebral fracture status was assessed. RESULTS: Significant differences in structure and BMD measurements were found between patients before and after heart transplantation (P <. 05). In 17 (42%) of 40 transplant recipients, vertebral fractures were found. Although structure measurements were significantly different between patients with and those without fractures (P <.05), BMDs were not. Correlations between time after transplantation and some structure measurements were moderately significant (P <. 05), but such correlations with BMD measurements were not. CONCLUSION: MR imaging-derived structure measurements in the calcaneus are useful for monitoring bone changes after heart transplantation and assessing vertebral fracture status.

Adult↗
PubMed1999

Minimally-invasive versus conventional aortic valve replacement--perioperative course and mid-term results.

OBJECTIVE: We performed a case-control-study to compare perioperative and mid-term results of minimally invasive with conventional aortic valve replacement. METHODS: Between 8/96 and 7/97, 113 patients underwent isolated aortic valve replacement (minimally invasive: 29, conventional: 84) in our Department. Diagnosis, ejection fraction, pressure gradient/regurgitation fraction, age, gender and body-mass-index were used as matching criteria for the case-control-study. For qualitative data correspondence was requested, for quantitative data deviations up to 10% were accepted. With these criteria 25 patients of the minimally invasive group were matched to 25 patients of conventional group. All patients were reexplored 1 year after aortic valve replacement. Statistical analysis was done by the Fisher's exact test for qualitative data and the Mann-Whitney test for quantitative data. RESULTS: We implanted 15 (20) bioprosthesis' and 10 (five) mechanical prosthesis' in the minimally invasive, respectively, conventional group. There were no statistically significant differences between both groups with respect to the perioperative course, only duration of surgery (mean 201.6 vs. 143.9 min, P < 0.01) and extracorporeal circulation (mean 116.1 vs. 71.3 min, P < 0.01) as well as aortic-cross-clamp-time (mean 77.9 vs. 46.9 min, P < 0.01) were significantly longer in the minimally invasive group. Postoperative complications occurred in one patient of the minimally invasive group (dissection of the right coronary artery) and four patients of the conventional group (third degree AV block, pneumothorax, grand mal convulsion, cardiopulmonary resuscitation). Two patients, one of each group, died during follow-up for unknown reasons. Follow-up revealed no significant differences with respect to clinical and echocardiographic data, but the shorter skin incision was cosmetically more accepted by patients of the minimally invasive group. Minor paravalvular leaks occurred in four patients of the minimally invasive and three patients of the conventional group as diagnosed by transthoracic echocardiography. CONCLUSIONS: Both surgical techniques may be performed with comparable perioperative and mid-term results, but the better cosmetic result in the minimally invasive group is paid by a longer duration of surgery.

Adult↗
PubMed1998

Aortocoronary Vein Bypass in a Patient with Type II Heparin-Associated Thrombopenia: A Case Report

Two types of heparin-associated thrombopenia (HAT) can be distinguished. Patients with type II HAT (HAT II) present a particularly difficult management problem when they require full anticoagulation. There is no consensus about the proper anticoagulation management for patients with HAT II who have to undergo cardiopulmonary bypass (CPB). We present a HAT II patient who underwent successful aortocoronary saphenous vein grafting. Sodium-danaparoid (SD) was used for anticoagulation. The anti-factor Xa level was kept below the values reported in the literature for patients undergoing CPB. We did not observe any fibrin formation during the time of CPB or any severe postoperative hemorrhage, which is frequently described in the literature. We discuss the management of our patient with SD intra- and postoperatively.

Journal Article↗
PubMed1998

Implications of End-Stage Renal Disease on Cardiac Surgery.

End-stage renal failure requiring dialysis is considered a significant risk factor in cardiac surgery. To assess the risk we performed a retrospective analysis of 17 patients with end-stage renal failure who underwent open heart surgery during 1994 and 1995. Pre-, peri-, and postoperatively we evaluated the following factors: renal failure etiology, risk factors, concurrent diseases, previous heart diseases, complications, mortality, and long-term outcome. All patients were dialyzed on the day before surgery. Intraoperative hemofiltration was performed in each patient. The first postoperative hemodialysis was performed on the second postoperative day or earlier for hyperkalemia or pulmonary edema. Postoperative complications occurred in seven patients: three patients expired postoperatively of noncardiac and nonrenal causes and four died during follow-up. With an average follow-up of 16.5 months (range 7-30 months) NYHA class had improved by an average of 1.7 in the 10 patients who were alive and their quality of life was acceptable. Because of these acceptable short- and long-term results and relatively low operative risk, we support an approach of prompt diagnostic work-up and surgical intervention when necessary.

Journal Article↗
PubMed1998

Coronary artery bypass grafting in a patient with type II heparin associated thrombopenia.

Two types of heparin-associated thrombopenia can be distinguished. Patients with the type II condition present a particularly difficult management problem when they require full anticoagulation. There is no consensus about the proper anticoagulation management for type II patients who have to undergo cardiopulmonary bypass. The case is reported of a type II heparin-associated thrombopenia patient who underwent successful aortocoronary saphenous vein grafting. Sodium-danaparoid was used for anticoagulation. The anti-factor Xa level was kept below the value reported in the literature for patients undergoing cardiopulmonary bypass. No fibrin formation was observed during the time of cardiopulmonary bypass, nor was any severe postoperative haemorrhage seen, as is frequently described in the literature.

Aged↗
PubMed1998

[Measurement of the humidity of inspired air in ventilated patients with various humidifer systems].

INTRODUCTION: Humidification of inspired gas in artificially ventilated patients positively influences mucociliary function and secretolysis. We performed this study to examine the properties of heat and moisture exchangers in comparison with hot water humidifiers and dry artificial ventilation. METHODS: We measured inspired humidity with a special sensor in 41 patients after coronary artery bypass grafting with cardiopulmonary bypass. Three Heat and Moisture Exchangers (HME) and a hot water humidifier were used to humidity the inspired gas of artificially ventilated patients. Humidity measurements were compared. RESULTS: Hot water humidifiers produced the highest humidification (average of 38.4 mg/l, 37-43 mg/l); lowest humidification was produced by dry artificial ventilation (average of 8.7 mg/l, 6-11 mg/l). Heat and moisture exchangers (HME) produced humidity between 24 and 36 mg/l. Highest humidification was produced by HME hygrobac s (average of 32.2 mg/l, 31-36 mg/l) and hygrovent s (average of 31.4 mg/l, 29-35 mg/l); lowest humidification was produced by HME hygroster (average of 28.6 mg/l, 24-31 mg/l). Multifactorial analysis shows a significant impact of the humidification method on the humidity of inspired gas. The multiple comparison procedure (Tukey) shows significant differences (alpha = 0.05) between all humidification techniques on inspired gas except the heat and moisture exchangers hygrobac s and hygrovent s. CONCLUSIONS: Hygrobac s and hygrovent s may be an alternative to hot water humidifiers. Further clinical studies of HMEs and hot water humidifiers will be necessary to evaluate the influence of inspired gas humidity on the outcome of artificially ventilated patients.

Air↗
PubMed1998

Atopic dermatitis.

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Child, Preschool↗
PubMed1997

Results of cardiac operations in five kidney transplant patients.

Because of the paucity of literature reports about cardiac operations in renal-transplant patients we performed a retrospective study encompassing all such patients operated upon in our institution in 1993 and 1994. During this time 5 renal transplant patients underwent cardiac surgical procedures between 1 and 9 years after transplantation: in 4 patients coronary artery bypass grafting (CABG) was carried out and in one patient aortic valve replacement. We analyzed pre-, peri-, and postoperative data. Late results were obtained by questionnaire from the patients' primary physicians. Short- and long-term results were excellent. Mortality was 0%. At late follow-up (8-23 months) all patients were in NYHA class II or better. Postoperatively all patients experienced a clear improvement of their cardiac symptoms. None of the transplanted kidneys deteriorated. One patient who had to undergo intermittent hemodialysis preoperatively improved so much that she did not require any dialysis postoperatively. Although the total number of patients in this study is limited we believe it can be stated that renal transplant patients can undergo cardiac operations with generally good results.

Adult↗
PubMed1997

Cardiac surgery in patients with end-stage renal failure.

End-stage renal failure is commonly considered a significant factor for an increased risk after coronary artery bypass grafting. This holds true for patients who have received a kidney transplant (NTX group) as well as for patients who require chronic hemodialysis (HD group). To assess the risk in our population we performed a retrospective analysis of 22 patients with end-stage renal failure (HD group: 17, NTX group: 5) who underwent cardiac surgery. The perioperative course was compared to a normal population. In addition to standard data we assessed the following factors: renal failure etiology, risk factors, concurrent diseases, duration of renal failure, function of renal graft, ECG (paying special attention to signs of previous myocardial infarctions and rhythm disorders), results of cardiac catheterization and coronary angiography, NYHA class and urgency of operative intervention. Complications and mortality were the main measures of the perioperative course. We analyzed the hospital charts retrospectively and requested the patients' physicians to complete a questionnaire about the patient's present condition. All HD group patients were dialyzed on the day before surgery. The first postoperative HD was performed for hyperkalemia or signs of volume overload (pulmonary capillary wedge pressure > 20 mmHg) when signs of pulmonary function deterioration were seen. HD was successful in treating these conditions. 3 of the 17 patients on HD expired postoperatively, 4 died within 3 years, all of unrelated diseases. Mortality and morbidity was 0% in the NTX group. In one NTX patient who required intermittent HD preoperatively because of poor renal graft function, renal function improved postoperatively, presumably secondary to better renal perfusion, and he did not require HD after his cardiac surgery. By surgical intervention the NYHA class of all patients improved (by 1.6 on the average) as well as their quality of life. Because of these good short- and long-term results and relatively low operative risk we support an approach of prompt work-up and surgical intervention when necessary in HD and NTX patients.

Adult↗
PubMed1996

An asexual fungus has the potential for sexual development.

The availability of cloned genes that control sexual reproduction (mating type genes) in high fungi has allowed us to consider the causes of failure to mate in asexual fungi. We report here that the asexual fungus Bipolaris sacchari has a homolog of the MAT-2 gene of its sexual ascomycete relative Cochliobolus heterostrophus. The B. sacchari MAT-2 sequence is highly similar to that of C. heterostrophus MAT-2 and, in fact, functions in transgenic C. heterostrophus. Thus, the asexual nature of B. sacchari is not due to absence or mutation of MAT. When either of the C. heterostrophus MAT genes was transformed into B. sacchari, the recipient could neither self nor cross with other B. sacchari strains, in contrast to transgenic C. heterostrophus strains which can do both. Persistent asexuality of B. sacchari, in spite of the presence of complementary functional MAT genes, suggests that this fungus lacks genes other than MAT which are essential for mating. Notably, the transgenic B. sacchari strains were sometimes able to initiate, but not complete, sexual development in interspecific pairings with C. heterostrophus. Transcript analysis showed that the B. sacchari MAT-2 gene is expressed in transgenic C. heterostrophus and that the C. heterostrophus MAT genes are expressed in transgenic B. sacchari. No transcript of the native B. sacchari MAT-2 gene was detected under any growth condition tested.

Amino Acid Sequence↗
PubMed1996

Isolation and characterization of two novel genes expressed in germinating conidia of the obligate biotroph Erysiphe graminis f.sp. hordei.

A cDNA library was constructed from germinating conidia of the obligate biotrophic fungus, Erysiphe graminis DC ex Mérat f.sp. hordei Em. Marchal (Egh). Subtractive hybridization and differential screening were carried out. Two cDNA clones, cEgh7 and cEgh16, which were highly expressed in germinating conidia, but not in ungerminated conidia, were selected for further characterization. The corresponding genomic sequences, gEgh7 and gEgh16, were isolated from a cosmid library and sequenced. The gEgh7 gene contains an open reading frame (ORF) that codes for a 249-amino-acid (aa), Pro-rich polypeptide with a repeated primary structure. Expression studies in planta indicated that gEgh7 may have a function in the development and maturation of conidia. The ORF of gEgh16 is interrupted by two introns of 91 and 119 bp. It encodes a 251-aa polypeptide of unknown function. This gene belongs to a multigene family and is expressed during all developmental stages of Egh in planta and may be associated with hyphal growth.

Amino Acid Sequence↗
PubMed1995

[Small intestine transplantation. Experimental microsurgical model in rats].

Small bowel transplantation may eventually become the definitive solution for those patients who suffer from irreversible intestinal failure and that currently depend on parenteral nutrition for survival. Microsurgical transplantation models in rats are widely used for the application of a great variety of immunological and physiological tests. Herein we report our experience after 30 intestinal harvestings and 12 intestinal transplantations in rats. The following criteria were established to assess the surgical procedures: operative time (harvesting and back table, cold ischemic time and warm ischemic time), vascular and intestinal complications and gut histology before and after transplantation. Average time for the donor surgery (harvesting and back table) was 97.19 min. Average warm ischemic time (includes vascular anastomoses) was 115 min. Histological assessment after 3, 4 and 5 hours of cold ischemia (lactated Ringer's solution with 2.4% mannitol at 4 degrees C) showed only mild ischemic changes. Two thrombotic complications were observed: one at the site of the portalcava anastomosis and one at the aortic suture. Hypovolemic shock was the most common cause of death (9/12) and there was no survival beyond 48 hours. Post-transplantation gut histology showed moderate ischemic injury. We conclude that the harvesting technique, as well as the preservation method used are adequate to obtain grafts in a fast and reliable fashion. However, the number of rats transplanted in this experience do not permit statistical analysis of morbidity and mortality at the present time.

Animals↗