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Biomedical subjects

W Horn

Publications and source records attributed to W Horn.

At least 19 recordsLinked to original sources
PubMed2004

[Structured concept for the establishment of a broad and ambulatory care of patients with type 2 diabetes: one-year evaluation of a regional teaching organization].

BACKGROUND: The increasing prevalence of diabetes mellitus and its long-term complications are associated with an expanding social medical problem. In order to originate an established teaching and training program on a physician-based level in short time, three specialist diabetes centers from Lübeck transferred their concept to a diabetes organization based on 17 physicians who had only rarely undertaken any diabetes teaching before. We investigated the achievement and effectiveness of this concept in a prospective multicenter evaluation one year after the patients had received structured diabetes teaching by the organization. PATIENTS AND METHODS: Physicians and their teaching staff were trained by the specialists from the diabetes centers according to an official agreement. Patients were treated by each practice, while the diabetes teaching was done centrally by the organization through a diabetes assistant/dietician based on a modified official diabetes teaching and training program (ZI-program). 230 of 250 patients (120 male, 110 female) were reinvestigated one year after they had received the teaching. The group consisted of 179 non-insulin-treated (NIB; 94 via physicians, 85 via specialists) and 51 insulin-treated (IB; 19 via physicians, 32 via specialists) participants. RESULTS: The average age of NIB was 60.4+/-9.8 years, while IBs were 68.8+/-7.3 years old. HbA (1c) values were reduced in both groups, NIB and IB, by approximately 1% (NIB: 7.59+/-1.97% to 6.59+/-1.84%; IB: 8.47+/-1.35% to 7,36+/-1,38 %; p < 0,001). In the NIB-group the BMI was reduced by 0,64+/-0,14 kg x m (-2), whereas it was increased in the IB-group by 0.33+/-0.24 kg x m(-2) (NIB: 30.55+/-0.40 to 29.91+/-0.39 kg x m(-2), p < 0.001; IB: 28.83+/-0.74 to 29.16+/-0.75 kg x m(-2), p = 0.82). CONCLUSION: The transfer of established teaching and training concepts of specialist diabetes centers to a newly founded, physician-based diabetes organization resulted in a broad, effective and long-lasting medical care of patients with type 2 diabetics treated without or with insulin. The results are superior to those of other evaluations based on diabetes training ZI-programs.

Aged↗
PubMed2001

AI in medicine on its way from knowledge-intensive to data-intensive systems.

The last 20 years of research and development in the field of artificial intelligence in medicine (AIM) show a path from knowledge-intensive systems, which try to capture the essential knowledge of experts in a knowledge-based system, to data-intensive systems available today. Nowadays enormous amounts of information is accessible electronically. Large datasets are collected continuously monitoring physiological parameters of patients. Knowledge-based systems are needed to make use of all these data available and to help us to cope with the information explosion. In addition, temporal data analysis and intelligent information visualization can help us to get a summarized view of the change over time of clinical parameters. Integrating AIM modules into the daily-routine software environment of our care providers gives us a great chance for maintaining and improving quality of care.

Artificial Intelligence↗
PubMed2001

Support for fast comprehension of ICU data: visualization using metaphor graphics.

OBJECTIVES: The time-oriented analysis of electronic patient records on (neonatal) intensive care units is a tedious and time-consuming task. Graphic data visualization should make it easier for physicians to assess the overall situation of a patient and to recognize essential changes over time. METHODS: Metaphor graphics are used to sketch the most relevant parameters for characterizing a patient's situation. By repetition of the graphic object in 24 frames the situation of the ICU patient is presented in one display, usually summarizing the last 24 h. RESULTS: VIE-VISU is a data visualization system which uses multiples to present the change in the patient's status over time in graphic form. Each multiple is a highly structured metaphor graphic object. Each object visualizes important ICU parameters from circulation, ventilation, and fluid balance. CONCLUSION: The design using multiples promotes a focus on stability and change. A stable patient is recognizable at first sight, continuous improvement or worsening condition are easy to analyze, drastic changes in the patient's situation get the viewers attention immediately.

Artificial Intelligence↗
PubMed2000

Factors associated with patients' participation in rehabilitation services: a comparative injury analysis 12 months post-discharge.

PURPOSE: To determine key characteristics or factors associated with rehabilitation participation during the first year following discharge for persons with either traumatic brain injury (TBI), spinal cord injury (SCI), intra-articular fracture (IAF), or burn injury (BURNS). METHOD: Medical records and longitudinal survey [telephone questionnaire] data were collected for persons in the four injury groups and analyzed using hierarchical logistic regression procedures for each domain of factors. RESULTS: The only significant predictors with odds ratios greater than one were those for vocational rehabilitation participation. TBI patients lacking private insurance were 2.6 times more likely to participate in vocational rehabilitation; older SCI and TBI patients are about twice as likely to participate in vocational rehabilitation; and finally those with IAF or BURNS who are married at 12 months post discharge are 11.5 and 4.4 times respectively more likely to participate in vocational rehabilitation. CONCLUSION: Those lacking valuable socio-economic resources, such as private insurance (for TBI) and social support systems provided by marriage (for BURNS and IAF patients) are much more likely to be referred to vocational rehabilitation. This is true for older SCI and TBI patients as well. Lacking such resources, patients may be viewed by referral agents as less likely to benefit from in or outpatient rehabilitation.

Adult↗
PubMed1998

Determinants of self-efficacy among persons with spinal cord injuries.

The purpose of this study was to determine the factors affecting self-efficacy among persons with spinal cord injury (SCI). The study population consisted of 105 persons with SCI who were discharged from one of eight hospitals in north central Alabama between October 1989 and September 1992. Data were derived from a retrospective acute-care medical record review and 12-month annual follow-up telephone interviews. The findings indicate that high self-efficacy is significantly associated with less severe neurological impairment, being white, employed at injury, having a high-school education or beyond, and having an unintentional injury. In terms of marital status our data indicate the odds of divorced persons having high self-efficacy are 8.2 (CL = 0.919, 74.1) times those of married persons. In addition, 64% of those who were divorced during the 12 months after injury had high self-efficacy compared to 50% of those who were divorced prior to injury.

Activities of Daily Living↗
PubMed1997

Effective data validation of high-frequency data: time-point-, time-interval-, and trend-based methods.

Real-time systems for monitoring and therapy planning, which receive their data from on-line monitoring equipment and computer-based patient records, require reliable data. Data validation has to utilize and combine a set of fast methods to detect, eliminate, and repair faulty data, which may lead to life-threatening conclusions. The strength of data validation results from the combination of numerical and knowledge-based methods applied to both continuously-assessed high-frequency data and discontinuously-assessed data. Dealing with high-frequency data, examining single measurements is not sufficient. It is essential to take into account the behavior of parameters over time. We present time-point-, time-interval-, and trend-based methods for validation and repair. These are complemented by time-independent methods for determining an overall reliability of measurements. The data validation benefits from the temporal data-abstraction process, which provides automatically derived qualitative values and patterns. The temporal abstraction is oriented on a context-sensitive and expectation-guided principle. Additional knowledge derived from domain experts forms an essential part for all of these methods. The methods are applied in the field of artificial ventilation of newborn infants. Examples from the real-time monitoring and therapy-planning system VIE-VENT illustrate the usefulness and effectiveness of the methods.

Artificial Intelligence↗
PubMed1996

Effects of dietary n-3 fatty acid supplementation in men with weight loss associated with the acquired immune deficiency syndrome: Relation to indices of cytokine production.

Cytokines may be involved in weight loss and disturbances of metabolism associated with human immunodeficiency virus (HIV) infection. Dietary n-3 fatty acids reduce the production of interleukin-1 (IL-1) and tumor necrosis factor (TNF) by peripheral blood mononuclear cells (PBMC) in normal humans and prevent IL-1 and TNF anorexia in animals. Accordingly, we studied the nutritional and metabolic effects of a 10-week trial of dietary fish oil (MaxEPA 18 g/day) in men with weight loss due to acquired immune deficiency syndrome (AIDS). Twenty men were enrolled, and 16 completed the 10-week supplementation period. Prior weight loss was 13.7 +/- 1.8 kg(17.4 +/- 1.6% body weight, means +/- SE). Food intake, body composition, blood chemistries, serum cytokine concentrations, in vitro production of IL-1 and TNF by PBMC, and clinical course were followed. A subset of subjects (n=12) underwent stable isotope infusions to measure de novo hepatic lipogenesis (DNL), an in vivo metabolic index that is influenced by cytokine presence and has previously been found to be elevated in AIDS. An unsupplemented group of men with AIDS wasting (10.4 +/- 2.4 kg weight loss, 13.1 +/- 2.2% body weight) was monitored for 10 weeks as controls. Baseline food intake (2,395 +/- 177 kcal/day and 95.1 +/- 7.2 g protein/day), body weight, percent fat, and fat-free mass were unchanged over the 10-week supplementation period. Serum triglycerides were reduced in hypertriglyceridemic subjects, confirming compliance with fish oil supplementation and suggesting that their hypertriglyceridemia was at least in part due to overproduction. Serum TNF and IL-1 were undetectable before or after fish oil supplementation. Serum interferon alpha (IFN) was measurable but did not change. In vitro production of IL-1 and TNF by PBMC was markedly reduced both at baseline and after fish oil supplementation in this population, even in the presence of new AIDS complications, compared with normal controls. The metabolic measurement DNL fell and weight was gained (2.1 +/- 1.3 kg) in subjects who did not develop new AIDS-related complications, but further increases in DNL and further weight loss were observed in subjects who developed a new AIDS complication (p<0.05 for interaction between new complication and change in DNL). No changes in body weight, food intake, serum triglycerides, serum cytokines, or DNL were observed in the unsupplemented group. We conclude that fish oil is a weak anticytokine agent that is unable to overcome the metabolic and nutritional consequences of acute AIDS-related complications but may exert a clinical anticytokine effect in stable AIDS patients. Cytokine production by PBMC is not a useful or reliable marker of in vivo cytokine activity in AIDS patients with weight loss. In contrast, an integrative functional index that is sensitive to cytokine presence in tissues (hepatic DNL) correlated with clinical response. These findings are relevant to the design of future studies of more potent anticytokine agents, such as thalidomide.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Utilizing temporal data abstraction for data validation and therapy planning for artificially ventilated newborn infants.

Medical diagnosis and therapy planning at modern intensive care units (ICUs) have been refined by the technical improvement of their equipment. However, the bulk of continuous data arising from complex monitoring systems in combination with discontinuously assessed numerical and qualitative data creates a rising information management problem at neonatal ICUs (NICUs). We developed methods for data validation and therapy planning which incorporate knowledge about point and interval data, as well as expected qualitative trend descriptions to arrive at unified qualitative descriptions of parameters (temporal data abstraction). Our methods are based on schemata for data-point transformation and curve fitting which express the dynamics of and the reactions to different degrees of parameters' abnormalities as well as on smoothing and adjustment mechanisms to keep the qualitative descriptions stable. We show their applicability in detecting anomalous system behavior early, in recommending therapeutic actions, and in assessing the effectiveness of these actions within a certain period. We implemented our methods in VIE-VENT, an open-loop knowledge-based monitoring and therapy planning system for artificially ventilated newborn infants. The applicability and usefulness of our approach are illustrated by examples of VIE-VENT. Finally, we present our first experiences with using VIE-VENT in a real clinical setting.

Algorithms↗
PubMed1996

Enhancement of BALB/c 3T3 cells transformation by 1,2-dibromoethane promoting effect.

Two of the most representative halogenated aliphatic hydrocarbons, 1,2-dibromoethane and 1,1,2,2-tetrachloroethane, were tested in the two-stage cell transformation model for analysing the promoting ability. Both of these compounds had previously been found to exert genotoxic effects, probably acting as moderate initiators. BALB/c 3T3 cells were initiated with subtransforming doses of N-methyl-N-nitro-N-nitrosoguanidine or 3-methylcholanthrene and then exposed to a chronic treatment with different non-transforming dosages of the two haloalkanes. 1,1,2,2-Tetrachloroethane did not exert any promoting activity in that system. By contrast, significant promoting effects by 1,2-dibromoethane were observed both in cells treated with N-methyl-N-nitro-N-nitrosoguanidine and in cells treated with 3-methylcholanthrene. Promotion of the transformation process initiated with 3-methylcholanthrene was detectable when confluent cells in the chemical-treated plates were replated in the level-II amplification test. This experimental procedure allowed cells to perform further rounds of replications and transformed foci to became detectable. Results gave evidence for a promoting role of 1,2-dibromoethane in multistep carcinogenesis, probably responsible for the higher oncogenic ability of this compound with respect to 1,1,2,2-tetrachloroethane.

3T3 Cells↗
PubMed1995

1,2-Dibromoethane as an initiating agent for cell transformation.

The two-stage transformation assay increases the sensitivity of cells to chemicals and permits detection of carcinogens acting as initiating agents. 1,2-Dibromoethane, a representative halogenated aliphatic, has been tested in the two-stage BALB/c 3T3 cells transformation test at dosage from 16 microM to 128 microM. This dose range is much lower than those previously found efficient in transforming BALB/c 3T3 cells. Apart from the lowest dose, which induced borderline effects, all the other assayed dosages appeared to induce heritable changes in the target cells. The initiated cells were revealed as fully transformed foci both in the combination with a chronic promoting treatment and also by allowing cells to perform more rounds of cell replication. The results clearly show that 1,2-dibromoethane can act as an initiator of cell transformation.

3T3 Cells↗
PubMed1995

[VIE-PNN: an expert system for calculating parenteral nutrition of intensive care premature and newborn infants].

Daily renewed composition of parenteral nutrition for premature and full-term newborn infants in intensive care is time consuming and prone to inherent calculation errors. We developed a knowledge based system, VIE-PNN (Vienna Expert System for Calculating Parenteral Nutrition of Neonates) for calculating the proposed composition of parenteral nutrition on the basis of the calculating algorithm used at our neonatal intensive care unit. The system needs manual input on postnatal age, body weight, serum electrolytes (or normal values if not available), amount and content of additional oral feeds, venous access (peripheral or central), total amount of fluid intake, and complications such as sepsis (reduced lipid supply) or cholestasis (reduced amino acid supply). The parenteral nutrition proposal may interactively be modified by the attending physician. There are possibilities for error detection to reduce the probability of typing or calculation errors. The system was developed to run on IBM compatible PCs and has been tested clinically. We describe the problem domain, system structure, clinical evaluation of VIE-PNN and the calculation of a standard parenteral nutrition solution from the data stored in the system's database.

Algorithms↗
PubMed1993

Automatic knowledge base refinement: learning from examples and deep knowledge in rheumatology.

MESICAR is a second generation expert system which contains very general descriptions of rheumatological disorders in the primary medical care field. With the help of a detailed hierarchical description of the human anatomy the system is able to support diagnostic decisions. The paper describes how machine learning techniques are used to automatically construct more specific disease descriptions for common, frequently occurring cases. The system MESICAR-LEARN implements a learning method which integrates analytical and empirical learning techniques. Cases diagnosed by MESICAR form the training examples, and MESICAR's knowledge base is used as domain theory. The learned concepts are integrated into a hierarchy of disease descriptions. They support efficient and fast reasoning on common cases in addition to the general diagnostic support afforded by MESICAR's deep knowledge.

Algorithms↗
PubMed1991

General pharmacology, toxicology and future clinical development of HOE 077.

The prolylhydroxylase inhibitor HOE 077 which has proven to be liver-selective in animals was tested in general pharmacological and toxicological studies for unwanted effects and safety. The results of these studies permit clinical development. A single-dose study in healthy volunteers was performed which showed that kinetics and main metabolites in man were similar to those found in animals. Aspects of the future clinical development of HOE 077 are discussed.

Animals↗
PubMed1989

Paradoxical effects of retinal in neutrophil stimulation.

Retinal stimulates the activity of phospholipase C and superoxide (O2-) release in neutrophils. The latter response is comparable in magnitude to that observed when phorbol 12-myristate 13-acetate (PMA) is the stimulating agent. Cells treated with retinal, however, do not undergo degranulation, nor do they exhibit the formation of intracellular vesicles, as is commonly observed with other agents (e.g. Lochner, J. E., Badwey, J. A., Horn, W., and Karnovsky, M. L. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 7673-7677). Retinal promotes redistribution of the activity of protein kinase C from a soluble to a particulate fraction in neutrophils, and this redistribution precedes O2- release. Superoxide release stimulated with retinal, however, is largely insensitive to inhibitors of protein kinase C (1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7); staurosporine). These compounds substantially block both O2- release and the phosphorylation of two proteins with molecular masses of about 47 and 49 kDa when the stimulus is PMA. The data indicate that retinal and PMA elicit the formation of active protein kinase C complexes of different natures, or that the mechanism of stimulation of O2- release by retinal does not involve this kinase. The significance of these observations to the common use of retinoids as inhibitors of protein kinase C is discussed.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1989

[Increase of oxygen partial pressure and acceleration of wound healing by tetrachlorodecaoxide].

63 transcutaneous measurements of oxygen pressure and 36 series of infrared thermograms in 9 hypoxic wounds showed that topical administration of tetrachlorine decaoxide (TCDO) results in increased oxygen supply of the wound. This effect is associated with improvement of the skin temperature and decrease of the pathological temperature difference between the wound and the surrounding tissue. TCDO can induce physiological wound healing, since it improves the mechanisms of the immune defence system, wound cleansing, granulation, and epithelialization in slow-healing wounds.

Adult↗
PubMed1988

Synergistic stimulation of neutrophils. Possible involvement of 5-hydroxy-6,8,11,14-eicosatetraenoate in superoxide release.

Neutrophils stimulated with optimal amounts of tumor-promoters that activate protein kinase C (e.g. mezerein, phorbol 12,13-dibutyrate) are known to release large quantities of superoxide: approximately 40-50 nmol O2-/min/10(7) cells. Previous studies have shown that treatment of neutrophils with the calcium ionophore A23187, or with 5-hydroxy-6,8,11,14-eicosatetraenonate (5-HETE), dramatically increased the ability of these cells to release O2- in response to suboptimal concentrations of the stimulants mentioned. In this manuscript, we provide data relevant to the basis of this augmentation of O2- release. The synergy with ionophore A23187 exhibited a partial requirement for extracellular Ca2+, whereas that with 5-HETE exhibited a near absolute requirement for that cation. Neutrophils stimulated with optimal amounts of tumor-promoters are known to exhibit a redistribution of protein kinase C activity from the soluble to a particulate fraction. A redistribution of kinase activity was not observed in cells stimulated synergistically. On the other hand, ionophore A23187 and 5-HETE increased the binding of a suboptimal amount of [3H] phorbol 12,13-dibutyrate to intact neutrophils by approximately 25 and 50%, respectively. Inhibitors of protein kinase C (i.e. sphingosine, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine) substantially blocked O-2 release from neutrophils stimulated either synergistically or with optimal levels of tumor-promoters. These data suggest a role for 5-HETE in modulating O-2 release by neutrophils and are discussed in relation to models of the interactions of protein kinase C with membranes.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1988

Reduction of cytochrome c by oral mucosa of patients with oropharyngeal cancer.

Superoxide radicals and other reactive oxygen products are likely to play a role in the development of mouth cancer since they are able to convert penultimate carcinogens present in cigarette smoke into ultimate carcinogens. Those radicals can be generated, e.g., by phagocytes infiltrating inflamed mucosa or by semiquinone radicals present in cigarette tar. We therefore measured the ability of oral mucosa of patients with oropharyngeal tumors to reduce cytochrome c. All patients were heavy smokers and drinkers. It was found that patient mucosa had by far more reducing power than control mucosa. Within the control group, smokers' mucosa was most active. When tested, the cytochrome c reduction was not inhibitable by superoxide dismutase or copper(II)3,5-diisopropylsalicylate. We hypothesize that reduction of cytochrome c by oral mucosa of smokers and patients with mouth cancer is primarily due to residues of cigarette tar containing conjugated quinones of mixed oxidative states which are strong reductants as well as producers of oxygen-centered radicals.

Cytochrome c Group↗