Biomedical subjects
Publications and source records attributed to A Weber.
In a climatized room of 30 M3 various gas-phase components of the side-stress smoke of cigarettes were quantitatively determined. In these experiments, acroleine, carbon monoxide, formaldehyde and nitric oxide reached relatively high values.
The effects of a 3 h exposition to 150 ppm CO on the flicker fusion frequency and the subjective assessment of 20 subjects have been investigated under two different experimental conditions (monotonous and activating). In the monotonous situation the exposition to CO has induced a relative "activation" of the subjective feelings.
Ciprofloxacin, an orally-absorbed fluoroquinolone is effective against multiply resistant Pseudomonas aeruginosa in cystic fibrosis patients. It is the only practicable agent against extraintestinal salmonellosis and shigellosis in developing countries. However, concern with the risk of arthropathy in young children has restricted its use in pediatrics. Pharmacokinetic studies with ciprofloxacin are limited in the pediatric population. As a result, the dose and frequency of administration are not established in children. In this study the possibility of using salivary concentrations as surrogate measure of serum concentrations was investigated. A pediatric formulation of the drug (125 mg per capsule) was prepared and compared to 250 mg tablets. Relative bioavailability was 105% (tablet/capsule). The time to peak salivary concentration and elimination rate from saliva were significantly different from serum (p < 0.01 and p < 0.05 respectively). The linear regression analysis of post-peak concentrations in serum and saliva yielded a slope of 1.25 and correlation coefficient of 0.83. It was also found that salivary concentrations may be contaminated from drug retained in the oral cavity. The conclusion was drawn that salivary concentrations could not be reliably used as a surrogate measure of serum levels for therapeutic drug monitoring.
The purpose of this study was to test the role of the mineralocorticoid receptor (MR) in the circadian activity of the hypothalamus-pituitary-adrenal (HPA) system of elderly healthy subjects. Nine elderly subjects (age: 66.2 +/- 7.7 years) were treated for 8 days with both the MR antagonist spironolactone and a placebo in a randomized, single-blind cross-over order. After treatment, we studied the circadian profiles of ACTH, plasma cortisol and saliva cortisol. No significant change in ACTH concentrations emerged. However, there were significant increases in circadian minimal (52.4 +/- 26.7 versus 33.3 +/- 14.4 nmol/l), mean (166.2 +/- 24.9 versus 133.0 +/- 18.3 nmol/l), and maximal cortisol concentrations (389.7 +/- 57.7 versus 335.4 +/- 45.0 nmol/l). Also, in the diurnal trough, we found an increase in saliva cortisol concentrations. Compared to young healthy controls, spironolactone treatment had stronger effects in the elderly. We therefore conclude that: 1) MR is involved in the human HPA system regulation; 2) the MR participates in the regulation of circadian nadir and peak activity of the HPA system; and 3) the HPA system in the elderly is more vulnerable to dysregulation at the level of the MR.
In a prospective study, over a period of four years 11,528 anonymous questionnaires concerning premature unfitness for work among civil servants were evaluated. The questionnaire was devised by the investigators. The main items of interest were: age, sex, career and occupation, main diagnosis and accompanying symptoms, duration of illness, rehabilitation measures, and working capacity including medical assessment of unfitness for work. Included in this study were 9,348 investigations (excluded were reactivations); 40.9 % were from women and 58.9 % from men. The median age was 54 years (women 52, men 55). The range of illnesses among all those investigated included a large number of psychological disorders (43.3 %, n = 4,052) (diagnosis group F of ICD-10). Second place was taken by muscular/skeletal diseases (ICD-10 group M) in 17.4 % of cases (n = 1,630), and third place by cardiovascular diseases (ICD-10 group I) in 10.4 % of cases (n = 972). The median duration of the main disease was 24 months. Classified as no longer fit for work were n = 7,033 persons, corresponding to 75.2 % of those investigated. Among those unfit for work, psychological disorders were the reason in 46.2 % of cases (men 42.6 %, women 53.4 %). In this first prospective study of illness-related premature unfitness for work in civil servants, psychological and psychosomatic illnesses were found to be the 'number one' illness among persons taking early retirement. The median age at which these persons became unfit for work was 52 in women and 55 in men. In view of the high prevalence of psychological disorders, and the increasing tendency towards early retirement and the considerable jump forward in the age this happens compared to in previous studies with small collectives, a preventive strategy must be developed which takes into account the evidence gained in social-medical and occupational-medical practice.
For diagnosis of instability in case of ruptures of the lateral ankle joint ligaments a special ultrasound examination technique was established. In 41 patients with acute ruptures and 8 patients with chronic instabilities a prospective preoperative sonographic instability-testing was performed and compared to intraoperative result. A sensitivity of 0.96 for injuries of the lig. fib. tal. ant. and 0.79 for the lig. fib. calc. proves the exactness of this method. This technique is easy to perform and the result can be documented. This examination is accepted by the patients.
Rifampin and two of its major metabolites, 25-O-desacetylrifampin and 3-formylrifamycin SV, were quantitated in serum, urine, and aqueous solutions by high-pressure, reverse-phase liquid chromatography. This rapid, precise, and simple method utilizes a single-step extraction, dual-wavelength monitoring, and quantitation by comparison of the absorbance of the drug or metabolite with that of an internal standard; the wavelengths used are 337 nm and 254 nm. The degrees of precision are +/- 1.3% and + 4.0% for rifampin only (within run and run to run); recovery in the assay is linear, with concentrations of up to 20 micrograms/ml. Comparison of this method with the reference bioassays yielded a good correlation (r = .975). Short turnover time and small sample size make the assay ideal for the monitoring of therapeutic drug concentrations and for pharmacokinetic studies.
If endocrine ophthalmopathy progresses despite conservative treatment then indications for surgical decompression are: loss of visual acuity, increasing strabism, and severe keratopathy. Endonasal microsurgery ensures a binocular view onto the intranasal landmarks of the orbital walls and allows simultaneous decompression of the medial and inferior wall as well as a good relief of pressure at the orbital apex. Surgical decompressions were performed on 29 orbits in 19 patients, 16 by using the endonasal microsurgical, 3 via external approach. The microscopic approach was entirely comparable with regard to the reduction of proptosis with a mean improvement of 4.2 mm against a mean of 4.7 mm by external approach and a mean 0.2 of better visual acuity in both procedures. The microsurgical technique is considered superior to an external approach avoiding external scars, neural pain, and reportedly less diplopia. The healing phase and the hospitalization time are shorter.
Insertion of a sufficient number of electrodes is important for a successful use of cochlear implants. We investigated the results of scala vestibuli insertion for cochlear implantation in cases of obstructed scala tympani. In a series of 200 cochlear implantations, scala vestibuli insertion was successfully performed in 4 cases with obstruction of the scala tympani. Etiologies included a temporal bone fracture, severe otosclerosis and malformations of the cochlea. The maximum insertion depth obtained via the scala vestibuli was 30 mm. Postoperative results were comparable to patients in whom conventional scala tympani insertion was performed. No adverse effects related to the site of insertion were observed. Scala vestibuli insertion offers a valuable alternative in cases of obstructed scala tympani that can be employed for a variety of etiologies.
PURPOSE: This prospective study explores the efficacy of a combined approach by intranasal microsurgical dacryocystorhinostomy and fiberglass endoillumination of the tear passage for difficult cases of lacrimal sac or nasolacrimal duct obstruction. METHODS: Microscopic dacryocystorhinostomy was performed in 67 patients with lacrimal obstruction and for revision of external dacryocystorhinostomy. Improved endonasal visualization by microscope and combination with endoillumination of the tear passage allows instant identification and opening of the lacrimal nasal sac without skin incision. Silicon tubes were used for bicanalicular intubation. The patients were prospectively observed for at least 1 year. RESULTS: The operation was well tolerated by all patients. In 95%, a persistently open tear passage was successfully established. No serious complications were observed. CONCLUSION: Endoillumination of the lacrimal sac is useful for locating the sac precisely and refining the endonasal operation technique.
In 35 patients with thyroid-associated orbitopathy, nonresponsive to conservative treatment, an endonasal microscopic approach with bimural osteotomy was performed for decompression in two ways. While in group A the periorbita was resected, and fat septa were cut, in group B periorbital strips were left, and fat septa were respected. In accordance with other authors, resection of the periorbital and cutting fat septa will improve vision and proptosis, but in up to 30% of the patients de novo diplopia occurs. Our data favor the assumption that a more conservative endonasal microscopic decompression of the orbita leaving periorbital strips and fat septa achieves similar good results for reduction of proptosis and visual gain but creates less often de novo diplopia in primary gaze. Based on our experience, rehabilitation for thyroid-associated arbitopathy comprises as a first step orbital endonasal decompression with cooperation of the ophthalmologist, then if necessary as a second step strabismus surgery, and thirdly eyelid repair for scleral show.
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Ten pediatric patients, aged 8.5-19 years, with active symptomatic Crohn's disease, received a three-week period of continuous elemental enteral alimentation with no other form of treatment. All patients in this study were selected according to the following criteria, which were applied consecutively: (1) newly diagnosed patients with no previous treatment for Crohn's disease, (2) disease activity index over 200, and (3) no complication requiring surgery. All patients experienced a clinical remission and improved their immunologic and nutritional status during the elemental enteral alimentation. The mean disease activity index for the whole group was 307.0 +/- 23.6 (range: 203 to 413) before and 69.2 +/- 11.4 (range: 15 to 114) after the feeding period. Significant increases in body weight, triceps skinfold, mid-arm circumference, serum transferrin and mean percentage of T lymphocytes were also observed. Following cessation of enteral alimentation, a small declining dose of prednisone was used during a one-year follow-up period. Eight of the ten patients were still in clinical remission three months after the feeding period and their nutritional status had continued to improve during that period of time.
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Dental prosthetic restorations (crowns and FPDs) are currently produced mainly by conventional dental technology methods. The automation of the production process can be achieved by the use of CAD/CAM techniques. In addition, it has become possible to use materials that previously could not be processed for technical reasons or could not be processed economically, especially high-performance ceramics. Although CAD/CAM methods for producing fixed restorations are of increasing interest, little information has been published about their mode of operation and functionality. To date, studies have focused mostly on special systems. However, basic studies are lacking. Basic research on the most important aspects of CAD/CAM fixed dental restorations from the viewpoint of production, information technology, and dentistry/dental technology are the subject of a current research project. The aim of this study is the presentation of preliminary results. The CAD/CAM process for fixed restorations was analyzed and broken down into single steps. In order to examine the influence of the single steps in the process chain, a computer test model with the teeth of the maxilla and mandible in static occlusion was developed and reverse engineered. While producing the test model, fundamental knowledge regarding the manufacturing of dental restorations with functional occlusal surfaces was gained. The intersection of the maxillary and mandibulary occlusal surfaces allows the qualitative analysis of occlusal contacts analogous to the conventional technique. Furthermore, a quantitative assessment of the size of the occlusal contacts and the measurement of intersection is possible.