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Biomedical subjects

E Schuster

Publications and source records attributed to E Schuster.

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

Long-term follow-up of Ru-106/Rh-106 brachytherapy for posterior uveal melanoma.

BACKGROUND: Currently available information about survival, local tumor control rates, secondary enucleation rates, and visual acuity following Ru-106/Rh-106 applicator therapy for choroidal and ciliochoroidal melanomas is limited in terms of duration of follow-up among surviving patients. METHODS: The authors performed a retrospective descriptive study of the rates of survival, local treatment failure, secondary enucleation, and visual acuity decrease in 140 patients (141 eyes) with choroidal or ciliochoroidal melanoma treated by Ru-106/Rh-106 applicator radiotherapy between 1964 and 1976. Median follow-up duration among surviving patients in this series was 17.3 years (mean 18.6 years). The Kaplan-Meier method was used to estimate cumulative survival rates and event rate curves. Multivariate Cox proportional hazards modeling was used to identify prognostic clinical variables associated with the various evaluated outcomes. RESULTS: The 15-year survival rate based on all causes of death was 48.0% (standard error=4.4%), and that based on confirmed and suspected metastatic uveal melanoma was 66.7% (standard error=4.5%). The cumulative 15-year rates of local treatment failure and secondary enucleation were 36.8% (standard error=4.4%) and 34.4% (standard error=4.5%) respectively. The cumulative 10-year rates of visual acuity loss to less than 20/200 and no light perception were 62.8% (standard error=4.4%) and 40.6% (standard error=5.2%) respectively. Prognostic factors associated with death from confirmed and suspected metastatic melanoma were greater tumor diameter and anterior tumor location. Greater tumor diameter was associated with local treatment failure. Baseline visual acuity equal to or worse than 20/200 was associated with profound visual acuity loss. CONCLUSIONS: Although a high proportion of treated eyes eventually lost a great deal of vision, and although many treated eyes ultimately underwent secondary enucleation, a substantial number of patients treated by plaque radiotherapy in this series survived for well over 10 years and retained the tumor-containing eye with a visual decrease of varying severity.

Adolescent↗
PubMed2000

Epinephrine application via an endotracheal airway and via the Combitube in esophageal position.

OBJECTIVE: To compare plasma concentrations and cardiovascular effects of epinephrine after application via a conventional endotracheal airway and via the esophageal lumen of a new emergency airway, the esophageal tracheal Combitube. DESIGN: Prospective, randomized study. SETTING: Center for Biomedical Research, University of Vienna. SUBJECTS: Fourteen juvenile swine received either an endotracheal tube (Group A) or a Combitube in esophageal position (Group B). INTERVENTIONS: In Part I of the study, epinephrine was administered during spontaneous beating of the heart; in Part II, epinephrine was administered during cardiopulmonary resuscitation, using a ten-fold higher dosage in Group B, respectively. MEASUREMENTS: Plasma epinephrine levels were measured 1, 2, 3, 5, 7, 10, 15, and 30 mins after application. Systolic arterial blood pressure and cardiac output in Part I, and end-tidal CO2 and coronary perfusion pressure in Part II were recorded. MAIN RESULTS: In Part I, increased levels of plasma epinephrine and systolic arterial pressure were maintained significantly longer in Group B when compared with Group A. In Part II, no significant differences between the groups were found with regard to plasma epinephrine levels and hemodynamic variables. CONCLUSION: Epinephrine applied via the esophageal lumen of the Combitube in a ten-fold higher dosage has similar effects on plasma epinephrine levels and hemodynamic variables compared to endotracheal administration.

Animals↗
PubMed1999

Localization of non-Mhc collagen-induced arthritis susceptibility loci in DBA/1j mice.

One approach to understanding common human diseases is to determine the genetic defects responsible for similar diseases in animal models and place those defective genes in their corresponding biochemical pathways. Our laboratory is working with an animal model for human rheumatoid arthritis called collagen-induced arthritis (CIA). We are particularly interested in determining the location of disease-predisposing loci. To that end, we performed experiments to localize susceptibility loci for CIA in an F2 cross between the highly susceptible mouse strain DBA/1j and the highly resistant mouse strain SWR/j. Specifically, a quantitative trait locus analysis was performed to localize regions of the mouse genome responsible for susceptibility/severity to CIA. One susceptibility locus, Cia1 in the major histocompatibility locus, had been identified previously. Two additional loci were detected in our analysis that contribute to CIA severity (Cia2, Cia3) on chromosomes 2 and 6. A third locus was detected that contributes to the age of onset of the disease. This locus (Cia4) was located on chromosome 2 and was linked to the same region as Cia2. Determining the identity of these loci may provide insights into the etiology of human rheumatoid arthritis.

Animals↗
PubMed1999

Angiotensin-converting enzyme and angiotensin II receptor 1 polymorphism in coronary disease and malignant ventricular arrhythmias.

OBJECTIVES: It has been reported that patients carrying the angiotensin-converting enzyme (ACE) deletion DD genotype with the angiotensin II type 1 (AT1) C allele are at increased risk for myocardial infarction. The frequency distribution of the ACE and AT1 receptor gene polymorphism and their possible relation regarding malignant ventricular arrhythmias in patients with coronary artery disease (CAD) and left ventricular dysfunction was determined. METHODS: The ACE I/D and AT1 A/C polymorphisms (using polymerase chain reaction) in 100 Caucasian patients suffering from CAD with a history of malignant ventricular arrhythmias treated with an implantable cardioverter defibrillator (ICD group) was compared to 127 age-matched Caucasian patients with CAD and no history of malignant ventricular arrhythmias (control group). All patients had reduced left ventricular ejection fraction of < 40% and were comparable regarding sex distribution, body mass index, ACE-inhibitor treatment, lipid status and duration of CAD. RESULTS: The prevalence of DD/CC in the ICD group was significantly higher (19% versus 10%, p < 0.0001). The risk for malignant ventricular arrhythmias was associated with the combination of ACE D and AT1 C alleles (odds-ratio: 2.4, 95% confidence interval 1.41 to 3.94, p < 0.001). The distribution of ACE and AT1 genotypes was not different between the two group. CONCLUSIONS: Patients with coronary artery disease and left ventricular dysfunction carrying ACE D and AT1 C alleles are at increased risk for development of malignant ventricular arrhythmias. Because of available pharmacological inhibitors, these results may have clinical implications for the prevention of sudden cardiac death.

Aged↗
PubMed1999

[Performance of vacuum pumps used during implantation of hip endoprostheses with an innovative cementing technique--a comparative study].

The increase in intramedullary pressure during implantation of a cemented total hip prosthesis is the decisive pathogenic factor in the development of an embolism. The logical countermeasure aimed at preventing bone marrow and fat emboli is reduction of pressure. Drainage of the femoral canal enabled by the bone-vacuum cementing technique substantially reduces intraoperative fat embolism and cardiopulmonary events. The aim of the present study was to compare the efficiency of two suction pumps used with this technique. In-vitro and In-vivo measurements of pressure were obtained to characterize the properties of the Vakufix pump and the Sterivap pump. In vitro experiments showed that the length of the suction tube has no influence on the performance of the pumps. A useful vacuum in the medullary canal was achieved In-vivo with both pumps (mean-209.3 mbar). The vacuum obtained with the Vakufix pump was higher (+16%) than that obtained with the Sterivap pump. Owing to the complexity of the system, we would not recommend the use of the Sterivap pump for evacuating the femoral canal.

Aged↗
PubMed1998

The university training programs in Austria.

A description is given of Austria's currently operational framework of training opportunities and post-doctoral courses in Medical Informatics. The description includes a brief outline of the currently valid curriculum in informatics and the methods on how to specialise in medical informatics within this framework.

Austria↗
PubMed1998

Predictors of outcome in patients with implantable cardioverter defibrillators.

UNLABELLED: This study determined the impact of clinical characteristics on shock occurrence and survival in patients with implantable cardioverter-defibrillator (ICD). METHODS AND RESULTS: During a follow-up of 27 +/- 18 months, the actuarial incidence of appropriate shocks in 200 consecutive patients was 18, 36 and 72% at 1, 3, and 5 years, respectively. Coronary artery disease was the only significant predictor for shock occurrence (relative risk 1.32, p = 0.03). The actuarial incidence of total mortality was 10, 17 and 33% at 1, 3, and 5 years, respectively. The most powerful predictors for total mortality were: New York Heart Association functional class (NYHA) III (relative risk 4.8, p = 0.001) and a history of congestive cardiac failure (relative risk 3.6, p = 0.01). CONCLUSION: During long-term follow-up, the majority of patients receive appropriate shocks. No strong predictors for shock occurrence can be identified from the data analyzed. A history of congestive cardiac failure and the NYHA III are the most powerful predictors for total mortality. These clinical factors may provide valuable criteria to identify patients who will benefit from the implantation of ICD.

Arrhythmias, Cardiac↗
PubMed1998

Concentration of endogenous tPA antigen in coronary artery disease: relation to thrombotic events, aspirin treatment, hyperlipidemia, and multivessel disease.

Tissue plasminogen activator (tPA) is the major plasminogen activator responsible for dissolving blood clots found in blood vessels. However, elevated concentrations of tPA antigen were found to be related to adverse events in patients with coronary artery disease (CAD). Considerable controversy about the significance of these results exists. The goal of this cross-sectional study was to identify independent determinants for tPA antigen concentrations in patients with CAD, to possibly clarify the above paradoxical relationship. The baseline tPA antigen concentrations of 366 patients with angiographic evidence of coronary sclerosis were determined. Univariate analysis showed that age (P=0.013), angiographic extent of disease (P<0.001), presence of angina at rest (P<0.001), diabetes mellitus (P=0.004), hypercholesterolemia (P=0. 045), hypertriglyceridemia (P=0.015), and chronic intake of nitrates (P<0.001) were significantly and positively related to tPA antigen concentration, while the chronic intake of aspirin was inversely related to tPA antigen (P<0.001). In addition, plasminogen activator inhibitor type 1 (PAI-1) activity was found to be significantly and positively associated with tPA antigen concentration (P<0.001). A multivariate analysis identified chronic low-dose aspirin therapy (P<0.001), PAI-1 activity (P<0.001), hypertriglyceridemia (P=0.005), the type of angina (P=0.026), multivessel disease (P=0.041), and hypercholesterolemia (P=0.043) as significant and independent determinants of tPA antigen. While hypertriglyceridemia and hypercholesterolemia both are related to the underlying disease, the type of angina and the number of involved vessels are linked to the severity and extent of disease, and all of them are indicators of a prothrombotic state found during the progression of CAD. In contrary, low-dose aspirin rather would decrease the likelihood of thrombotic events. The relation of tPA antigen to PAI-1 activity furthermore underlines the relation between tPA antigen concentration and a prothrombotic state. Therefore, the positive or-in case of aspirin therapy-negative correlation of these parameters with tPA antigen concentration would indicate that thrombus formation and simultaneous endothelial cell activation might be major determinants for tPA antigen concentration in CAD.

Adult↗
PubMed1997

Results of a community-based low-literacy nutrition education program.

A nutrition intervention focused on low-fat eating pattern changes was conducted among low-literacy participants in a Twin Cities Metropolitan area Expanded Food and Nutrition Education Program (EFNEP). A total of 134 EFNEP participants who participated in the intervention were compared to 70 comparison participants who received EFNEP nutrition education materials. Associations between changes in outcome variables specific to the intervention were evaluated using mixed-model regression analyses. The principal effects seen for this program were related to changes in eating pattern scales. More modest effects were seen in scales related to attitudes of low-fat eating, and although changes in dietary fat intake as measured by 24-hour dietary interviews suggested a positive intervention effect, this did not approach statistical significance.

Adult↗
PubMed1997

Effects of lidocaine, ajmaline, and diltiazem on ventricular defibrillation energy requirements in isolated rabbit heart.

The majority of patients with implanted cardioverter defibrillators (ICD) require antiarrhythmic (AR) drugs. ARs may increase defibrillation energy requirements. This study investigated the effects of lidocaine, ajmaline, and diltiazem on ventricular defibrillation energy needs. In 24 isolated rabbit hearts, the 50 and 80% successful defibrillation energy (ED50, ED80) was calculated in four phases: predrug baseline condition (phase 1), and phases 2, 3, and 4 with increasing concentrations of lidocaine, ajmaline, diltiazem (n = 18). Control experiments (n = 6) with only Tyrode's solution infusion indicated that the preparation was stable over time. Defibrillation energy requirements significantly (p < 0.05) increased with all ARs. Low, medium, and high lidocaine concentrations increased ED50 and ED80 to 146, 223, and 312% and 139, 207, and 285%, respectively. Ajmaline increased ED50 and ED80 to 133, 175, and 251% and 135, 208, and 285%, respectively. Diltiazem increased ED50 and ED80 by 175, 236, and 334% and 158, 212, and 286%, respectively. The results of this study demonstrate a dose-dependent increase in defibrillation energy requirements by using lidocaine, diltiazem, and ajmaline. In patients with ICDs, administration of these drugs might cause a critical increase in defibrillation energy requirements, resulting in device failure.

Ajmaline↗
PubMed1997

Prostaglandin E1 inhibits platelet decrease after massive blood transfusions during major surgery: influence on coagulation cascade?

BACKGROUND: A plunge in platelet count if often observed after massive blood transfusions during major surgery. This study was designed to assess whether the prophylactic administration of prostaglandin E1 (PGE1) might prevent this drop in platelet count. METHODS: Forty-five patients receiving massive transfusions of packed red blood cells (> 10 units) during major orthopedic surgery were enrolled in a prospective, randomized, double-blind, placebo-controlled study and divided into two groups: group 1 (therapy group) received intravenous PGE1 up to 30 ng/kg/min for 72 hours after surgery, and group 2 (placebo group) received a placebo during the same time period. RESULTS: The patients in group 1 suffered no reduction in platelet count and thus required no platelet concentrate transfusions. In contrast, a significant postoperative drop in platelet count (p < 0.05) was observed in the placebo group between days 3 and 5 after surgery when compared to the therapy group, necessitating transfusions of platelet concentrates in this group. Similarly, red blood cell count and hemoglobin were far more stable in the therapy group, which required fewer transfusions of red blood cells than did the placebo group (p < 0.05). There seemed to be a tendency toward a consumptive coagulation disorder in the placebo group as indicated by a decrease of fibrinogen levels, prothrombin time, and antithrombin III activity, and an increase of partial thromboplastin time. The incidence of adult respiratory distress syndrome was slightly lower in the therapy group. Last but not least, the length of intensive care unit stay was significantly shorter in the therapy group (p < 0.05). CONCLUSION: In our study, the administration of PGE1 prevented a reduction in platelet count. Furthermore, measurements of clotting activity furnished the possibility that PGE1 might inhibit transfusion-induced coagulation disturbances. We recommend that PGE1 should be considered in patients requiring massive transfusion during major surgery.

Adult↗
PubMed1997

The effect of anticoagulant therapy in primary and anorectic drug-induced pulmonary hypertension.

In a retrospective study, we tested the hypothesis that anticoagulant therapy with warfarin sodium (Coumadin) has a beneficial influence on the long-term prognosis in patients with primary pulmonary hypertension (PPH) and aminorex-induced plexogenic pulmonary hypertension. The study included a total of 173 patients from two European cities. One hundred four of these patients took the anorectic drug aminorex (Menocil), which was available in some European countries almost 30 years ago; 69 patients had pulmonary hypertension of unexplained etiology, ie, PPH. Fifty-six of the 104 aminorex-treated patients and 24 patients in the PPH group received warfarin after diagnosis was established. For analysis, patients were divided into four groups according to their history of aminorex intake and anticoagulant therapy. Survival time, changes in hemodynamics (pulmonary arterial pressure), and improvement in quality of life (scored by the New York Heart Association [NYHA] classification) were compared and analyzed. We found that aminorex-treated patients had a better long-term prognosis than those with PPH (7.5 vs 3.9 years; p < or = 0.001). The best mean survival time of 8.3 years was found in anticoagulated aminorex-treated patients, compared to 6.1 years in nonanticoagulated aminorex-treated patients. Moreover, aminorex-treated patients who received anticoagulant therapy soon after the onset of symptoms showed significantly better prognosis (10.9 years) than those who commenced treatment 2 years thereafter (5.9 years) (p < or = 0.05). In patients with PPH, systolic pulmonary pressure was shown to influence survival time significantly (p < or = 0.0005); however, this correlation was not found in aminorex-treated patients. An improvement of symptoms like dyspnea on exertion was seen in 44.8% of the anticoagulated aminorex-treated patients, while deterioration was evident in 72.2% of the nonanticoagulated aminorex-treated patients. In conclusion, our study has shown that anticoagulant therapy had a positive influence on long-term survival and a significant improvement in quality of life in patients with PPH, in particular in patients with a history of anorectic drug intake.

Adolescent↗
PubMed1997

Impact of growth factors on morphometric corneal endothelial cell parameters and cell density in culture-preserved human corneas.

PURPOSE: Donor corneas can be preserved for < or = 4 weeks in organ culture (31 degrees C) by using modified minimal essential medium (MEM). About one fifth of them have to be discarded, however, as disintegration of the endothelial cell monolayer-enhanced polymegethism, cell loss-occurs. The objective of this study was to investigate whether addition of insulin, dextran, and epidermal growth factor (EGF) makes corneal endothelial cells more viable, stable, and homogeneous. METHODS: Sixteen paired human donor corneas were cocultured in media supplemented with EGF and insulin-like growth factor (IGF) or in conventional modified MEM for 4 weeks. Endothelial parameters were evaluated at the outset and at days 7, 14, 21, and 28 of culture by using an automated digital image-analysis system. RESULTS: No significant differences were observed in the first 2 weeks of culture. Beginning with day 14, however, stabilization of endothelial cell patterns was evident for corneas cultured in supplemented culture media. CONCLUSION: Our data indicate that the addition of growth factors to culture media might increase the percentage of corneas available for transplantation and would also allow a significantly longer period of preservation.

Cell Count↗
PubMed1996

The interwoven architecture of the Mu transposase couples DNA synapsis to catalysis.

Mu transposition occurs exclusively using a pair of recombination sites found at the ends of the phage genome. To address the mechanistic basis of this specificity, we have determined both where the individual subunits of the tetrameric transposase bind on the DNA and where they catalyze DNA joining. We demonstrate that subunits do not catalyze recombination at the site adjacent to where they are bound, but rather on the opposite end of the phage genome. Furthermore, subunits bound to two different sites contribute to catalysis of one reaction step. This interwoven subunit arrangement suggests a molecular explanation for the precision with which recombination occurs using a pair of DNA signals and provides an example of the way in which the architecture of a protein-DNA complex can define the reaction products.

Amino Acid Sequence↗
PubMed1996

Ethical considerations when conducting ethnographic research in a nursing home setting.

In this article I provide an overview of ethical concerns when conducting ethnographic research in nursing home settings where participants are vulnerable and submissive to authority, and I consider how particular research methodologies may benefit the participants. The focus of the article is primarily on the issues of privacy and autonomy and the relationship between the researcher and the participant. My own experiences of doing research in a nursing home will be woven throughout the article, as will the accounts of other researchers who have studied life in nursing homes. In reflecting on my work as a researcher I have come to a deeper understanding of the ethical issues involved in doing research in a nursing home and of the importance of ethically sound research.

Aged↗
PubMed1994

Focus group responses of potential participants in a nutrition education program for individuals with limited literacy skills.

OBJECTIVE: To obtain information to direct the design and development of a nutrition intervention program targeted at a low-literacy audience. SUBJECTS: Thirty-nine female and two male clients of the Expanded Food and Nutrition Education Program (EFNEP) participated in five focus-group discussions. The focus groups included 23 African American, 9 white, 4 Southeast Asian, 1 American Indian, 2 Hispanic American, and 2 Middle Eastern EFNEP participants. DESIGN: All focus groups were moderated and co-moderated by University of Minnesota staff members. The focus groups were tape-recorded and transcribed. A written report was generated based on the independent evaluation of two staff members. RESULTS: We learned that EFNEP participants thought they would be motivated to change their eating habits for health concerns, including weight loss, and to help their families develop healthful eating habits. They mentioned several barriers to making changes, including extra time and money needed to purchase and prepare healthful foods, food preferences of family members, lack of interest and skills in cooking, and insufficient knowledge about which foods are healthful. Participants shared ideas for program content and delivery. CONCLUSIONS: Clients with limited literacy skills have valuable opinions and insights that program developers targeting this hard-to-reach group should hear. The EFNEP participants wanted simple, practical, and relevant information about what foods to eat and how to prepare them. They considered lectures an ineffective way to receive nutrition information, and they expressed a preference for hands-on activities that were enjoyable and allowed participants to share ideas and experiences.

Black or African American↗