PubMed Health⌕ Search

Biomedical subjects

S Kramer

Publications and source records attributed to S Kramer.

At least 19 recordsLinked to original sources
PubMed2006

Interventional stenting for ruptured iliac aneurysm following transplant nephrectomy.

Surgical removal of a failed kidney graft may lead to a variety of postoperative complications, development of an aneurysm being a relatively rare complication. We report the case of a 34-year-old man who developed an iliac aneurysm 13 years after transplant nephrectomy. Interventional stenting was performed upon the rupture of the aneurysm. Postintervention the function of the contralateral transplanted kidney was stable and the patient recovered. An endoleak was diagnosed after 1 week, which was also stented. No operative procedure was necessary. In conclusion, even in an emergency situation interventional stenting of a false iliac aneurysm after transplant nephrectomy may be a therapeutic option.

Adult↗
PubMed2006

[The construction of an empirically based social status index through optimal scaling as illustrated by Germany].

Numerous epidemiological studies have shown an association between social status and disease. In alcohol research, socio-economic status (SES) has been associated with drinking patterns, misuse and alcohol problems. SES is a construct which is usually built by using the indicators education, occupation or income separately or combined as a summary score. However, either approach involves theoretical assumptions about the explanatory value of a chosen indicator before the data have been analysed. In this study we have created a gender-specific metric social status indicator for Germany by using all three single SES-indicators (education, occupation, income). We used national representative data from a postal survey from 2000. The age range was restricted to 25 - 59 years. To construct the indicator we used optimal scaling (categorical principal components analysis). Therefore no theoretical assumptions were necessary about the hierarchical order of educational or occupational categories. The optimal-scaling approach allows variables to be scaled on different levels. We used education and occupation as the original categorical data and income (equivalent income) as continuous data. The result of the scaling is a two-dimensional solution. The first dimension explains that variance which could be described by status consistencies (corresponding levels for education, occupation and income). The second dimension of the indicator results from the low correlation between education and income for some individuals (status inconsistencies). The two-dimensional indicator yields differentiated results which would not be visible using a one-dimensional SES-indicator such as education or a summary score. With regard to drinking patterns there are clear differences between middle or low-educated women or men with higher incomes and other social groups. Middle or low-educated men or women with a high income are more likely to be heavy episodic drinkers than people in other social status groups.

Adult↗
PubMed2005

[Physical (in)activity in childhood and adolescence].

In the last two decades in Germany and other countries physical activity of children and adolescents declined while sedentary lifestyle increased. Physical inactivity in childhood and youth is related with coronary heart disease risk factors and higher prevalence of obesity. International recommendations suggest daily 60 minutes or more moderate to vigorous physical activity and less than 2 hours sedentary activity in leisure.

Adolescent↗
PubMed2005

Anti-nociceptive efficacy of carprofen, levomethadone and buprenorphine for pain relief in cats following major orthopaedic surgery.

A placebo-controlled, randomized blind study was conducted in cats (n = 60) after fracture repair to compare the analgesic effects as well as the side-effects of carprofen, buprenorphine and levomethadone during a 5-day treatment. Cats with severe shock symptoms or increases in blood urea nitrogen (BUN) and creatinine were excluded from the study. The cats were randomly assigned to four groups (n= 15). In group 1, carprofen was administered upon extubation at an initial dose of 4 mg/kg body weight, followed by one-third of that dose three times daily on days 2 to 5. In group 2, buprenorphine was administered in a single dose of 0.01 mg/kg body weight upon extubation and subsequently every 8 h. Levomethadone (group 3) was applied according to the same scheme at a dosage of 0.3 mg/kg body weight each time. The placebo (group 4) was given at the same time intervals as the opioids. Examinations were carried out prior to anaesthesia, between 30 min and 8 h after extubation, and on the following 4 days, 1 h after administration of the analgesics or the placebo as well as 1 h before the next administration. Pain and sedation evaluation was carried out with a visual analogue system (VAS) and with the aid of a numerical estimation scale (NRS). Pain was also scored by measuring mechanical nociceptive threshold of traumatized tissue. Plasma glucose and cortisol concentration, heart rate, respiration rate, blood pressure and body temperature were measured. Furthermore, a complete blood count and clinical chemistry including BUN, creatinine, alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH), arterial blood pressure (AP), total protein and electrolytes of the cats were checked on the day of admission as well as on the last day of this study (day 5). Defaecation and urination as well as wound healing were monitored. On the basis of the mechanical nociceptive threshold of the traumatized tissue, concentrations of plasma glucose and cortisol and pain assessment using NRS and VAS, carprofen was found to have better anti-nociceptive efficacy when compared with the two opioid analgesics, while the analgesic effect of levomethadone was similar to that of buprenorphine. However, the carprofen group also showed comparably high median NRS and VAS pain scores in addition to occasional broad deviations from the group mean on the first post-operative treatment day. Sedative effects were detected for buprenorphine and levomethadone; in addition, symptoms of central excitation were noted with levomethadone. There was no indication of any clinically relevant respiratory depressive or cardiovascular effects, nor of any undesired renal, gastrointestinal or hepatic effects of the analgesics applied. However, the somewhat insensitive examination methods did not permit sufficient evaluation of side-effects, particularly on the gastrointestinal tract and the kidneys. It was found that carprofen and buprenorphine were well-tolerated analgesics for a 5-day administration in the cat, whereas levomethadone caused central excitation in some cases in the dosage scheme used here. However, it was apparent that none of the tested analgesics induced sufficient analgesia in the post-operative phase. For this reason, suitable methods must be found to improve analgesia, particularly in the immediate post-operative phase.

Analgesics↗
PubMed2005

Incidence of post-anaesthetic arrhythmias in dogs.

OBJECTIVES: To assess the use of Holter monitoring for evaluating the incidence of post-anaesthetic cardiac arrhythmias and associated anaesthetic risk for two different anaesthetic protocols. METHODS: Patients undergoing orthopaedic surgery were randomly divided into two groups with different anaesthetic regimens (group A, isoflurane n = 30; group B, propofol n = 30). Two 24-hour Holter recordings were performed for each patient: the first directly following anaesthesia and the second, as a comparison, on the fifth postoperative day. RESULTS: Although all dogs were healthy on pre-anaesthetic cardiac evaluation, 56 dogs showed arrhythmias in the two 24-hour (Holter) electrocardiograms performed. However, the number of arrhythmias recorded was low in most cases (less than 10 supraventricular extrasystoles and less than 100 ventricular extrasystoles). One patient in group A showed 94 supraventricular extrasystoles during the second monitoring period. Three patients in each group developed more than 100 ventricular extrasystoles during both Holter recordings. There were no statistically significant differences between the two anaesthetic regimens or between the two recordings in both groups. CLINICAL SIGNIFICANCE: The two anaesthetic protocols investigated in this study did not induce an increased incidence of severe arrhythmias in healthy dogs in the post-anaesthetic phase.

Anesthetics, Inhalation↗
PubMed2003

A survey of the Predictive Toxicology Challenge 2000-2001.

MOTIVATION: The Predictive Toxicology Challenge (PTC) was initiated to stimulate the development of advanced techniques for predictive toxicology models. The goal of this challenge was to compare different approaches for the prediction of rodent carcinogenicity, based on the experimental results of the US National Toxicology Program (NTP). RESULTS: 111 sets of predictions for 185 compounds have been evaluated on quantitative and qualitative scales to select the most predictive models and those with the highest toxicological relevance. The accuracy of the submitted predictions was between 25 and 79 %. An evaluation of the most accurate models by toxicological experts showed, that it is still hard for domain experts to interpret the submitted models and to put them into relation with toxicological knowledge. AVAILABILITY: PTC details and data can be found at: http://www.predictive-toxicology.org/ptc/.

Animals↗
PubMed2003

Response of dogs to short-term infusions of carbohydrate- or lipid-based parenteral nutrition.

Parenteral nutrition (PN) is used to support intensive care patients. The risk for adverse metabolic effects depends on the composition of infused solutions and the duration of application. The present study in dogs compares metabolic and endocrine effects of two infusion solutions, with either triglycerides or glucose being the major energy sources, administered in a comparatively short infusion period (10 h/day). PN was administered for 9 days to two groups of five adult dogs to meet energy maintenance requirements. In group PN-LIP 61% of the total energy was derived from lipids and 22% from carbohydrates, compared with 21 and 62% in group PN-GLUC. Among routine haematology and clinical chemistry the plasma levels of glucose, triglycerides, insulin, insulin-like growth factor-I (IGF-I), glucagon, 3,5,3'-triiodothyronine and thyroxin were measured in non-infused dogs and at 2, 4, 6, and 8 h after the start of infusion at days 2 and 8 of the study. Infusions protocols did not cause gross metabolic aberrations. During the actual infusions glucose, triglyceride and insulin concentrations were elevated, each depending on the infusion solution. Concentrations of IGF-I, glucagon, 3,5,3'-triiodothyronine, thyroxin and cortisol did not change significantly. In conclusion short infusion periods of 10 h per day were tolerated by healthy dogs without adverse signs, which could improve practicability of PN also in clinical cases.

Animals↗
PubMed2003

Towards discovering structural signatures of protein folds based on logical hidden Markov models.

With the growing number of determined protein structures and the availability of classification schemes, it becomes increasingly important to develop computer methods that automatically extract structural signatures for classes of proteins. In this paper, we introduce and apply a new Machine Learning technique, Logical Hidden Markov Models (LOHMMs), to the task of finding structural signatures of folds according to the classification scheme SCOP. Our results indicate that LOHMMs are applicable to this task and possess several advantages over other approaches.

Algorithms↗
PubMed2003

[Comparison of the influence of different anesthetic protocols in the development of post-anesthetic arrhythmia in the dog].

Post-anesthetic holter monitoring was performed in 2 patient groups in order to compare the incidence of cardiac arrhythmias as a result of different anesthetic protocols. The 2 groups differed in their anesthetic protocol. Both groups received levomethadone as pre-anesthetic. The dogs in group A (n = 30) additionally received diazepam, the dogs in group B (n = 30) received propofol instead. Anesthesia was maintained by isoflurane in group A and a propofol constant rate infusion in group B. In each patient 2 holter monitorings were performed. The first recording began directly after anesthesia. As a comparison a second recording was performed on the 5th post-operative day. The recorded number of arrhythmias was low and no statistical difference was demonstrated between the 2 patient groups.

Anesthetics, Intravenous↗
PubMed2002

[Health-related quality of life in patients with chronic pain].

AIMS: An empirical comparison of the performance characteristics of 3 generic health-related quality of life (HRQL) measures in pain patients. METHODS: The Nottingham Health Profile (NHP), the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36), and the German Life Satisfaction Scale (FLZ-M) by Henrich et al. were simultaneously employed in a multicenter survey measuring the impact of pain on quality of life. The HRQL- instruments were incorporated into the German Pain Questionnaire (pain variables, CES-D, Pain Disability Index). RESULTS: Characteristics of 3294 pain patients of 13 pain facilities are detailed in tables 1-3. Six of the 8 SF-36- and 4 of the 6 NHP-scales show satisfactory item-total correlations, bottom- and ceiling-effects, and internal consistency. FLZ-M reliabilities are satisfactory. The item weighting procedure of the FLZ-M proves to be unnecessary. Principle component analyses result in 7 factors for the SF-36 and the NHP. Six of the SF-36-factors are fairly homogeneous. The heterogeneity of the NHP- factors is marked. Correlations of the HRQL scales with depression (CES-D), anxiety (STAI) and physical functioning (FFbH-R-18) are high in all related contents. All instruments discriminate well between headache and back pain patients, between several pain grades (v. Korff) and the 3 Mainz pain chronicity stages. CONCLUSIONS: The SF-36 has satisfactory to good psychometric properties in pain patients, the NHP item selection has to be improved. The FLZ-M weighting can be eliminated. The shortcomings of the SF-36 can be overcome by adding short scales on role functioning and pain (modular approach).

Adult↗
PubMed2002

Fragment generation and support vector machines for inducing SARs.

We present a new approach to the induction of SARs based on the generation of structural fragments and support vector machines (SVMs). It is tailored for bio-chemical databases, where the examples are two-dimensional descriptions of chemical compounds. The fragment generator finds all fragments (i.e. linearly connected atoms) that satisfy user-specified constraints regarding their frequency and generality. In this paper, we are querying for fragments within a minimum and a maximum frequency in the dataset. After fragment generation, we propose to apply SVMs to the problem of inducing SARs from these fragments. We conjecture that the SVMs are particularly useful in this context, as they can deal with a large number of features. Experiments in the domains of carcinogenicity and mutagenicity prediction show that the minimum and the maximum frequency queries for fragments can be answered within a reasonable time, and that the predictive accuracy obtained using these fragments is satisfactory. However, further experiments will have to confirm that this is a viable approach to inducing SARs.

Artificial Intelligence↗
PubMed2001

High-performance liquid chromatographic determination of the beta2-selective adrenergic agonist fenoterol in human plasma after fluorescence derivatization.

A sensitive high-performance liquid chromatographic method has been developed for the determination of the beta2-selective adrenergic agonist fenoterol in human plasma. To improve the sensitivity of the method, fenoterol was derivatized with N-(chloroformyl)-carbazole prior to HPLC analysis yielding highly fluorescent derivatives. The assay involves protein precipitation with acetonitrile, liquid-liquid-extraction of fenoterol from plasma with isobutanol under alkaline conditions followed by derivatization with N-(chloroformyl)-carbazole. Reversed-phase liquid chromatographic determination of the fenoterol derivative was performed using a column-switching system consisting of a LiChrospher 100 RP 18 and a LiChrospher RP-Select B column with acetonitrile, methanol and water as mobile phase. The limit of quantitation in human plasma was 376 pg fenoterol/ml. The method was successfully applied for the assay of fenoterol in patient plasma.

Adrenergic beta-2 Receptor Antagonists↗
PubMed2001

Laser cutting: influence on morphological and physicochemical properties of polyhydroxybutyrate.

Polyhydroxybutyrate (PHB) is a biocompatible and resorbable implant material. For these reasons, it has been used for the fabrication of temporary stents, bone plates, nails and screws (Peng et al. Biomaterials 1996;17:685). In some cases, the brittle mechanical properties of PHB homopolymer limit its application. A typical plasticizer, triethylcitrate (TEC), was used to overcome such limitations by making the material more pliable. In the past few years, CO2-laser cutting of PHB was used in the manufacturing of small medical devices such as stents. Embrittlement of plasticized PHB tubes has been observed, after laser machining. Consequently, the physicochemical and morphological properties of laser-processed surfaces and cut edges of plasticized polymer samples were examined to determine the extent of changes in polymer properties as a result of laser machining. These studies included determination of the depth of the laser-induced heat affected zone by polariscopy of thin polymer sections. Molecular weight changes and changes in the TEC content as a function of distance from the laser-cut edge were determined. In a preliminary test, the cellular response to the processed material was investigated by cell culture study of L929 mouse fibroblasts on laser-machined surfaces. The heat-affected zone was readily classified into four different regions with a total depth of about 60 to 100 microm (Klamp, Master Thesis, University of Rostock, 1998). These results correspond well with the chemical analysis and molecular weight measurements. Furthermore, it was found that cells grew preferentially on the laser-machined area. These findings have significant implications for the manufacture of medical implants from PHB by laser machining.

Absorbable Implants↗
PubMed2001

Physiological (antioxidant) responses of estuarine fishes to variability in dissolved oxygen.

Cycles of dissolved oxygen (DO) in estuaries can range from anoxia to various levels of supersaturation (200-300%) over short time periods. Aerobic metabolism causes formation of damaging reactive oxygen species (ROS), a process exacerbated by high or low DO. Fish can generate physiological defenses (e.g. antioxidant enzymes) against ROS, however, there are little data tying this to environmental conditions. We investigated physiological defenses generated by estuarine fishes in response to high DO and various DO cycles. We hypothesized that chemical defenses and/or oxidative damage are related to patterns of DO supersaturation. Specific activities of antioxidants in fish tissues should be positively correlated with increasing levels of DO, if high DO levels are physiologically stressful. We caged common benthic fishes (longjaw mudsucker, Gillichthys mirabilis, and staghorn sculpin, Leptocottus armatus, in CA and spot, Leiostomus xanthurus and pinfish, Lagodon rhomboides, in NC) during summer 1998 in two estuarine sites in southern North Carolina and two in central California. At each site a water quality meter measured bottom DO, salinity, temperature, depth, pH and turbidity at 30 min intervals throughout the study. These sites exhibited a wide variety of dissolved oxygen patterns. After 2 weeks in the cages, fish gills and livers were analyzed for antioxidant enzymes (glutathione peroxidase, catalase and superoxide dismutase) and the metabolite glutathione. All fish exhibited antioxidant enzyme activity. There was a significant site-dependent effect on all enzyme activities at the NC sites, with the most activity at the site with the highest DO cycling and the most DO supersaturation. There was a trend towards higher enzyme activities under high DO levels at the CA sites.

Adaptation, Physiological↗
PubMed2001

The treatment of moderate to severe psoriasis with a new anti-CD11a monoclonal antibody.

BACKGROUND: Anti-CD11a (hu1124) is a humanized monoclonal antibody directed against the CD11a subunit of LFA-1. This study investigated whether treatment with anti-CD11a antibody provides clinical benefit to patients with moderate to severe plaque psoriasis. METHODS: This was a double-blind, placebo-controlled, phase II, multicenter study. In total, 145 patients with minimum Psoriasis Area and Severity Index scores of 12 and affected body surface area of 10% or more were sequentially enrolled into low-dose (0.1 mg/kg, n = 22) or high-dose (0.3 mg/kg, n = 75) groups. Within groups, patients were randomized to treatment or placebo (n = 48) in a 2:1 ratio. Drug was administered intravenously at weekly intervals for 8 weeks. RESULTS: The percentage of subjects achieving more than 50% improvement in physician's global assessment at day 56 (1 week after final dose) was 15% and 48% for placebo and 0.3 mg/kg of drug, respectively (P =.002). A physician's global assessment of excellent (>75% improvement) was greater in the 0.3 mg/kg group versus placebo (25% vs 2%, P =.0003). Average Psoriasis Area and Severity Index scores at day 56 were 13.9 +/- 7.5 (placebo) and 10.9 +/- 8.4 (0.3 mg/kg) (P <.0001). Epidermal thickness was reduced in the 0.3 mg/kg group compared with the placebo group (37% vs 19%, P =.004). Treatment was well tolerated; mild to moderate flu-like complaints were the most common adverse events. White blood cell counts and lymphocyte counts transiently increased. Depletion of circulating lymphocytes did not occur. CONCLUSIONS: Anti-CD11a antibody administered intravenously in 8 weekly doses of 0.3 mg/kg was well tolerated and induced clinical and histologic improvements in psoriasis.

Adult↗
PubMed2001

Radiation oncology: contributions of the United States in the last years of the 20th century.

The advancements in radiation oncology in the past 50 years in the United States were probably more dramatic than those in the first half of the 20th century. Not only were there major technical achievements, but there was also an associated increase in the overall cure rates of cancer, from 20% at 5 years 50 years ago to now nearly 60% at 5 years. The cure rates in selected tumor sites at 5 years in 1950 and in 2000, respectively, were as follows: breast, 50% and 80%; colon and rectum, 40% and 85%; lung, 5% and 15%-20%; prostate, 40% and 80%; Hodgkin disease, 50% and more than 90%; cervix, 40% and 70%-80%; uterus (endometrium), 80% and more than 90%; bladder, 30% and 50%; head and neck, 30% and 60%; and esophagus, 2% and 15%. Much of this has been due to a broader array of techniques in radiation therapy available for treatment but also because of new emphasis on combined integrated modalitities (surgery, radiation therapy, and chemotherapy). New imaging techniques have contributed substantially, allowing better selection of patients for treatment and better selections of treatment modalities.

Combined Modality Therapy↗