Allergic contact dermatitis from topical diclofenac in Solaraze gel.
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Administration, Topical↗
Biomedical subjects
H Horn
Publications and source records attributed to H Horn.
Simulation of biofilm growth, substrate conversion and mass transfer under different hydrodynamic conditions.
The hydrodynamic conditions and the substrate load in biofilm systems are two main parameters which influence the biofilm growth in particular the structure, density and thickness. In a long term study on heterotrophic biofilms in biofilm tube reactors the investigation has focussed on mass transfer at the bulk/biofilm interface, the biofilm density and the substrate conversion rates. To study the mass transfer phenomena at the bulk/biofilm interface oxygen profiles have been measured directly in tube reactors with microelectrodes. Microelectrode studies, substrate conversion rates and biofilm densities were used to formulate model equations for the simulation of biofilm growth under different hydrodynamic and substrate conditions. It can be shown that the mass transfer at any time is strongly coupled with the growth conditions during the biofilm cultivation. On the one side the calculated Sherwood numbers were coupled to the present hydraulic conditions, on the other side in addition the growth conditions such as growth rate and Reynolds number during biofilm cultivation were considered.
Biofilms↗
2D simulation of transport and degradation in the River Rhine.
A simple 2D model has been developed for the simulation of mass transport and degradation of substances in the river Rhine. The model describes mass transport in the flow direction with a convective and a dispersive term. Transversal transport is described by segmenting the river and formulating a transversal exchange coefficient between the segments. Degradation can be formulated with any kinetics from first order to complex enzyme kinetics. The model was verified with monitoring data from the river Rhine. The hydrodynamic parameters such as dispersion coefficients and exchange coefficients were fitted to the conductivity, which was assumed to be non-degradable. The degradation term was fitted to ammonia values. The model was used to simulate measured concentrations of a readily (Aniline) and a poorly biodegradable substance (1,4-Dioxan) 10 m from the left river bank. It was the objective of this research program to develop a model which allows a realistic estimation of the locally and regionally predicted environmental concentration of chemical substances in the EU risk assessment scheme.
Ammonia↗
FLASHFLOOD: a 3D field-based similarity search and alignment method for flexible molecules.
A three-dimensional field-based similarity search and alignment method for flexible molecules is introduced. The conformational space of a flexible molecule is represented in terms of fragments and torsional angles of allowed conformations. A user-definable property field is used to compute features of fragment pairs. Features are generalizations of CoMMA descriptors that characterize local regions of the property field by its local moments. The features are invariant under coordinate system transformations. Features taken from a query molecule are used to form alignments with fragment pairs in the database. An assembly algorithm is then used to merge the fragment pairs into full structures, aligned to the query. Key to the method is the use of a context adaptive descriptor scaling procedure as the basis for similarity. This allows the user to tune the weights of the various feature components based on examples relevant to the particular context under investigation. The property fields may range from simple, phenomenological fields, to fields derived from quantum mechanical calculations. We apply the method to the dihydrofolate/methotrexate benchmark system, and show that when one injects relevant contextual information into the descriptor scaling procedure, better results are obtained more efficiently. We also show how the method works and include computer times for a query from a database that represents approximately 23 million conformers of seventeen flexible molecules.
Algorithms↗
Modelling the structure and function of extracellular polymeric substances in biofilms with new numerical techniques.
The objective of this study is the mathematical description of the structure and function of the extracellular polymeric substances (EPS) in biofilms. The basic assumptions of the EPS biofilm model are: the production of EPS in biofilms is coupled to the growth of micro-organisms the production of EPS is additionally coupled to the substrate conditions the EPS represent a considerable volume fraction of the matrix in biofilms and thus the density of the biofilms is strongly influenced by the EPS sorption of biocides and pollutants in biofilms occurs mainly to EPS the EPS can be used as an energy source during substrate limited phases. The mathematical model has been derived as a system of partial differential equations. The numerical solution of these complex balance equations has been done by a self-adaptive Galerkin-h-p-method. It can be shown, that on the one hand the simulation of substrate conversion and biofilm growth with the EPS-biofilm model yields similar results as the known biofilm models without consideration of the EPS fraction. On the other hand the advantage of the EPS-biofilm model is a better understanding of biofilm structure, which is mainly influenced by the EPS fraction in the biofilm. Furthermore, the sorption of pollutants, such as heavy metals and chlorinated organic substances, can be simulated in more detail.
Adsorption↗
CNS infection with clostridium septicum.
We present an unusual case of Clostridium septicum brain infection in a 72-yr-old woman who had no underlying malignant disease. The infection spread from a localized sit to the CNS causing gas formation. The patient died rapidly.
Aged↗
Size-exclusion chromatography of plasma proteins with high molecular masses.
Two different hydrophilic materials with large pores, Superose 6 and Fractogel EMD BioSec (S), which are designed for size-exclusion chromatography (SEC) of plasma proteins with high molecular masses, are tested for their performance on a preparative scale. The model mixtures are preparations of the clotting factors VIII (FVIII) and IX (FIX). A combination of a Fractogel EMD BioSec (S) column and a Superose 6 column has proved to be particularly effective for separations in a wide molecular size range, from several millions down to about 20,000. Superose 6 showed good results on a small scale as well as on a large scale, even in the molecular mass range over 1,000,000. However, recovery of FVIII clotting activity was less than 70% with this material and therefore not satisfactory. Fractogel did not perform well in terms of separation on a small scale. However, in the case of biopolymers with high molecular masses, separation was improved by using larger columns. With Fractogel, recovery of activity of the two clotting factors FVIII and FIX was satisfactory, above 80%. On a large scale, the active fraction in the clotting factor concentrate was successfully separated from the non-active fraction with either size exclusion (SE) material. In the preparation under investigation, the clotting factor VIII is found in a complex with the von Willebrand factor (vWF). The FVIII-vWF complex has a molecular mass of several millions. It dissociates in the presence of high concentrations of Ca2+ ions. Under such conditions FVIII and vWF were successfully separated with both SEC columns.
Chromatography, Gel↗
A recurrent glycine substitution mutation, G2043R, in the type VII collagen gene (COL7A1) in dominant dystrophic epidermolysis bullosa.
Dystrophic epidermolysis bullosa (DEB) is caused by mutations in the type VII collagen gene (COL7A1). Nearly all cases of dominant DEB are caused by glycine substitution mutations occurring within the triple helical region of type VII collagen, and most of the mutations are unique to individual families. In this study, we identified a patient of Hispanic-Mexican origin with a mild form of DEB, which resulted from a de novo dominant glycine substitution, G2043R, in exon 73 of COL7A1. We also investigated a Scottish family with a three-generation pedigree of dominant DEB, in whom the same glycine to arginine substitution mutation was demonstrated. This particular mutation has also been detected previously in three other families with dominant DEB: one Italian, one Hungarian and one Norwegian. Given the widespread geographical distribution of this mutation and the demonstration of its occurrence as a de novo event, G2043R therefore represents the first example of a mutational hotspot in dominant DEB. Interestingly, although both the Mexican and Scottish families we studied had some clinical features in keeping with the Pasini form of the disorder, there was considerable interfamilial variability as well as intrafamilial diversity in the affected individuals.
Adult↗
Reliability of electromagnetic articulography recording during speaking sequences.
For the development of malocclusions and speech disorders, major aetiological significance is attributed to orofacial malfunctions, especially of the tongue. The position of the tongue to the alveolar arch and teeth, particularly within the area of the tip of the tongue, is of special interest for orthodontists. Electromagnetic articulography is a new technique used to examine tongue function and to record its movement in the midsagittal plane. The aim of the study was to determine whether this procedure offers suitable and reliable results. Thirty-one subjects aged 14.3-37.3 years had to repeat speaking sequences five times. The German syllables they had to repeat were /asa/, /ascha/, /ata/, /ala/, /ana/, /aka/. The tongue movements were registered with an 'Articulograph AG 100'. Distances, angles and encircled planes were evaluated, and the proportion of intra-individual to overall variability was calculated in order to check the reliability of the courses of movement. Angles and distances especially showed, depending on the position of the receiver coils, strong reliability during speaking sequences, whereas area produced unfavourable results. The analysis of long trajectories and angles appeared favourable in order to describe the courses of movement. This required, however, a systematic assessment of functional movement with electromagnetic articulography.
Adolescent↗
[Improvement of an electromagnetic articulograph for registering tongue and lip movements].
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Electromagnetic Fields↗
Degradation pathways, analytical characterization and formulation strategies of a peptide and a protein. Calcitonine and human growth hormone in comparison.
Peptides and proteins differ from conventional chemical entities in their sensitivity to numerous environmental factors and their susceptibility to different degradation pathways. Therefore, complex analytical methodologies are necessary to characterize their molecular entity as well as to detect and quantify the possible degradation products. The formulation of these molecules for a pharmaceutical product requires stabilization by various excipients. Most of the products are brought to market as solutions or lyophilisates. In the first part, this article presents a comparison between the degradation profile of a peptide (calcitonine) and a protein (human growth hormone), in solution and as a freeze-dried product. The various analytical methods used to characterize and identify the degradation products are reviewed and discussed. The second part contains an overview of the different formulation strategies for calcitonine and human growth hormone. Finally, the different stress conditions used to obtain stability data are discussed critically. This leads on to general comments on the design of stability studies for peptide and protein drugs as pharmaceuticals taking into consideration the official guidelines.
Amino Acid Sequence↗
[Maximal force measurements of lip and tongue pressures and their significance for the diagnosis of orofacial dyskinesias].
The functioning of the orofacial muscular system essentially determines the shape of the jaw and of the dental arch as well as the position of the axis of the anterior teeth. Disturbances of the normal functioning can cause anomalies of the position of teeth or malformations of the bone structure. With the help of the newly developed device "Myometer 160" we now have the possibility to measure the intra- and extraoral forces. We examined 107 persons aged 8 to 37 years. The maximal force was measured by ventral tongue pressure, when the lips were pressed against each other and when a brass button was pulled. In addition clinical results as well as a functional status were ascertained in order to record orofacial dyskinesias. A significant connection between the age respectively the sex of the persons and the determined force was found. However, no clear relationship between the occlusal position respectively the functional anomaly and the results of maximal force was determined. Thus it does not seem sensible to use maximal force measurement within the framework of the determined. Thus it does not seem sensible to use maximal force measurement within the framework of the diagnosis of orofacial dyskinesias.
Adolescent↗
[Orthodontics and implantology. Their course and results after joint planning].
The therapeutical repertoire for treating patients with missing teeth was significantly expanded by the development of modern implant methods. We have performed a retrospective analysis covering all children who between 1977 and 1993 had been considered for implants as a method for gap management. All patients were pretreated up to early adolescence using standard orthodontic procedures. Unfortunately, it turned out that an originally planned implant was not suitable in approximately 2/3 of the patients because of inadequate alveolar conditions. These patients were subsequently treated by conventional orthodontic gap closure or adhesive prosthetics.
Adolescent↗
Microvascular anastomosis of interpositional vein grafts with sutures and a new mechanical device--a histologic and scanning electron microscopic study.
In an experimental study, a new mechanical device for microvascular anastomosis was compared with suture anastomosis. In 14 rabbits, seven end-to-end and seven end-to-side anastomoses of the jugular vein to interpositional vein grafts were done with a ring-pin device and by the conventional suture method. There was no significant difference between the patency rates of mechanical and suture anastomoses. The completion of mechanical anastomoses took one-third the time required for suture anastomoses. After 10 days, histologic and scanning electron microscopic examination revealed an uneventful reparative process at the anastomotic site with media atrophy and a continuous endothelial layer. At 4 weeks, occasional foreign body giant cells were seen between the polyethylene rings and surrounding connective tissue. The study confirms that the ring-pin device is safe and provides a faster way to do microvascular anastomoses than by suturing.
Anastomosis, Surgical↗
[Validating rehabilitation after stroke].
Evaluation of therapeutic efficacy in neurologic rehabilitation is methodologically limited by the well established polypragmasia and the lack of untreated controls. Controversial discussion is generated by the following topics: superiority of specific therapy versus spontaneous recovery, higher efficacy of in-patient-setting versus out-patient-setting and the value of neurorehabilitation treatment in latency of more than 1 year after the event. To develop a practicable method for the evaluation of efficacy, we surveyed retrospectively 30 patients after stroke in a sequential study design on 4 scheduled visits: first admission to in-patient rehabilitation, discharge to out-patient treatment, admission and discharge of second in-patient rehabilitation. Impairment, disability and handicap were documented by NIH-Stroke Scale, Barthel-Index, CGI, WWK-Pflegeskala N and Risk-Profile. A descriptive data-analysis implies a therapeutic gain of stroke rehabilitation in-patient setting which is apparently superior to out-patient treatment. A measurable therapeutic effect was evident even more than one year after the stroke.
Adult↗
Prognostic value of PCNA and cytokeratins for radiation therapy of oral squamous cell carcinoma.
In a retrospective pilot study we compared morphologically the first biopsies of 20 patients suffering from oral squamous cell carcinoma (OSCC) where preoperatively performed radiation therapy [gamma rays (cobalt-60)] was successful with 20 patients who underwent the same therapy without the expected success. All specimens were formalin fixed and paraffin embedded. We performed haematoxylin and eosin staining and immunohistochemistry (ABC-method) applying broad spectrum cytokeratin, cytokeratin (CK) 1 + 2, 3 + 6, 13 and anti-proliferating cell nuclear antigen (PCNA, PC10). The specimens of the patients with success of the radiotherapy showed statistically higher levels of PCNA positive tumour cells, measured by a computerised morphometric analysis system (VIDAS). These specimens showed significantly less CK 3-6 positive tumour cells than the specimens of the patients with failure of this therapy. The difference in the content of proliferating cell nuclear antigen might explain the different results of the performed radiation therapy. The difference in cytokeratin 3 + 6 expression might be linked with the different amount of benign hyperproliferation. Prospective studies are planned to prove the results.
Adult↗
[Diagnosis and differential diagnosis of sialo-odontogenic (glandular-odontogenic) cyst].
Sialo-odontogenic (glandular-odontogenic) cyst is a new entity in the classification of developmental epithelial odontogenic cysts. Differentiation of this type of odontogenic cysts from dentigerous cysts and keratocysts and also from cystic mucoepidermoid carcinoma is essential. A sialo-odontogenic (glandular-odontogenic) cyst is likely to show aggressive growth, so that complete resection is essential. We demonstrate sialo-odontogenic (glandular-odontogenic) cyst by presenting four new cases and differentiate it from a special type of odontogenic keratocyst and a typical cystic mucoepidermoid carcinoma.
Adult↗
[Gas in the portal vein system of the liver. Value of ultrasound].
We report on 9 patients presenting with different diseases of varying severity, who were found to have hepatic portal venous gas (HPVG) identified by diagnostic ultrasonography. Intrahepatic gas was a shortlasting phenomenon, which could not be seen radiologically in most cases. Earlier beliefs that HPVG is a poor prognostic sign associated with high mortality, should be revised.
Abscess↗