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Biomedical subjects

R Türk

Publications and source records attributed to R Türk.

At least 19 recordsLinked to original sources
PubMed1998

Reference standardization and triglyceride interference of a new homogeneous HDL-cholesterol assay compared with a former chemical precipitation assay.

A homogeneous HDL-c assay (HDL-H), which uses polyethylene glycol-modified enzymes and sulfated alpha-cyclodextrin, was assessed for precision, accuracy, and cholesterol and triglyceride interference. In addition, its analytical performance was compared with that of a phosphotungstic acid (PTA)/MgCl2 precipitation method (HDL-P). Within-run CVs were < or = 1.87%; total CVs were < or = 3.08%. Accuracy was evaluated in fresh normotriglyceridemic sera using the Designated Comparison Method (HDL-H = 1.037 Designated Comparison Method + 4 mg/L; n = 63) and in moderately hypertriglyceridemic sera by using the Reference Method (HDL-H = 1.068 Reference Method - 17 mg/L; n = 41). Mean biases were 4.5% and 2.2%, respectively. In hypertriglyceridemic sera (n = 85), HDL-H concentrations were increasingly positively biased with increasing triglyceride concentrations. The method comparison between HDL-H and HDL-P yielded the following equation: HDL-H = 1.037 HDL-P + 15 mg/L; n = 478. We conclude that HDL-H amply meets the 1998 NCEP recommendations for total error; its precision is superior compared with that of HDL-P, and its average bias remains below +/-5% as long as triglyceride concentrations are < or = 10 g/L and in case of moderate hypercholesterolemia.

Chemical Precipitation↗
PubMed1993

137Cs concentrations in lichens before and after the Chernobyl accident.

137Cs activities were measured in a variety of epigeic and epiphytic lichens in Austria before and after contamination by the Chernobyl fallout. For comparison, the activity of the naturally occurring 40K was also determined in each lichen sample. The high 137Cs activities found after Chernobyl suggest that lichens are suitable and inexpensive biological detectors of the fallout pattern.

Accidents↗
PubMed1993

Fine structure of the tendon of the human stapedius muscle: comparison of normals and clinically otosclerotic patients.

The tendon of the human stapedius muscle was studied in normal post mortem material and in clinical otosclerotic patients, using light and electron microscopy. Cross section profiles of collagen fibrils were measured in various regions of the tendon and the amount of elastin was estimated. The normal stapedius tendon consisted of three concentrically arranged portions: A cylindrical central part, a tube-like mid-portion, and a cortical layer. The central part was made up of collagen fibrils with only a few elastic fibers, the mid-portion contained collagen fibrils together with significantly more elastic material, while the cortical layer, again, showed a smaller amount of elastic fibers. Mean diameters of collagen fibrils in the central part of the tendon were 65.12 +/- 11.89 nm, in the intermediate layer 41.00 +/- 9.63 nm, and in the cortical layer 70.28 +/- 19.58 nm. Stapedius tendons from clinically otosclerotic patients, though showing the same construction, were characterized by significantly altered collagen fibrillar diameters (Mann-Whitney U-test). In the central part, mean diameters were reduced to 61.05 +/- 14.70 nm, in the mid-portion increased to 50.90 +/- 10.08 nm, and in the cortical layer reduced to 61.09 +/- 8.49 nm. The changes of collagen cross section profiles estimated for the entire tendon were significant as well: 59.68 +/- 18.74 nm in controls versus 57.82 +/- 12.53 nm in otosclerotic patients. Elastin content in the mid-portion of control stapedius tendons increased with age (13% at 35 years of age to 35% at 70 years of age).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[1,000 ear operations--a critical analysis and clinical consequences].

1028 ear operations which were performed by our department during the last few years are being analysed in the study. 649 of them were carried out to improve hearing, 245 to cure the middle ear; 120 were reoperations, and 14 could not be classified. The patients were diagnosed as follows: 280 with and 279 with other forms of cholesteatoma, 151 with otosclerosis, 20 with deformations, 89 with a trauma, and 20 with a tumour of the middle ear. Of these, only reoperations of cholesteatoma, chronic otitis media and tympanosclerosis were examined in further detail in this research. 54 (of a total of 280) patients diagnosed with cholesteatoma were surgically treated a second time. The reason for reoperation was recurrent cholesteatoma in 70% of the cases, and a planned second-look operation after one year in 30%. In second-look operations, ossicular chain reconstruction was performed in most cases, but in another 11%, recurrent cholesteatoma was found. The majority of recurrencies occurred either 2 to 4 years after primary operation or after 11 years. 44 of a total of 297 patients with chronic mesotympanic otitis media were re-operated on: 57% of them for recurrent inflammation, and 43% for ossicular chain reconstruction as a planned second-step operation. The majority of reoperations occurred within the first year after primary operation, continually decreasing for up to five years afterwards. The following conclusions can be drawn from these results: 1. Often the patients suffer from extended cholesteatoma, so that at first curative surgery is necessary, while the ossicular chain can be reconstructed by a second operation only.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Diagnosis and therapy of hearing disorders in early childhood].

The diagnosis and therapy of hearing loss in early childhood should start in the first year of live, otherwise there will arise special difficulties in the further development. The first steps in diagnosis are undertaken by various medical specialists, the exact determination of the hearing loss should be done at a pedaudiological center. The various methods of pedaudiologic measurement and the following therapy of children with hearing loss are presented.

Child, Preschool↗
PubMed1989

[The value of sonography in salivary gland tumors].

In a prospective study, 178 patients with tumours of the salivary glands were examined both clinically and by ultrasound. All patients have since been operated upon, and the diagnosis was confirmed histologically. The diagnostic accuracy of clinical examination is compared with that of ultrasound. Every tumour of the salivary glands could be diagnosed by ultrasound. In the benign group, an exact diagnosis of the tumour type was possible in 83% of cases. In the malignant group an exact diagnosis was only possible in 57% of cases. Furthermore, it is possible with ultrasound to recognise multiple and bilateral tumours, to determine whether a tumour is intra- or extraglandular, and to show the nature of the tumour (cyst, abscess, central necrosis) to a much greater extent than with clinical examination alone. In addition, a fairly good assessment of the cervical and intraglandular lymph nodes is obtained. We believe that ultrasound is of great importance in the diagnosis of tumours of the salivary glands.

Adenolymphoma↗
PubMed1989

[Principles of early management of deaf children].

First of all there is an introduction regarding the significance of hearing-defects in small children (0-3 years), concerning aswell the development of personality as also divergences in the development of language. After a short survey over the methods of early recognition of hearing defected small children and the supply of a hearing-aid a therapy-concept for early care of hearing defected small children is introduced. This therapy-concept was developed at the I. Ear-, Nose- and Throat-Clinic in Vienna and divides itself into three sections that run partially parallel. 1. Parent consultation: This represents the first step regarding the early recognition and is undertaken whilst a diagnosis is being made. 2. The setting up of the acoustical perception: As soon as the technical preliminaries are done, the early-training of small children with hearing-defects starts with a training of a constant turn toward the sound-source. The essential steps of this therapy are then explained in this study. 3. The prepare of speech: The training consists of three points of main effort: The setting up of vocabulary. The foundation of articulation and speech correction. Continued hearing-practice. The team executing this consists of an Ear-, Nose- and Throat-specialist, a psychologist and a logopedist.

Articulation Disorders↗
PubMed1989

[Objective determination of auditory threshold in the child].

In children who are difficult to test with dubious behavioural-audiometric results, brainstem electric response audiometry (BERA) is today the method of choice for accurate determination of hearing threshold. Oral sedation with the shortacting neuroleptic chloroprothixene allows BERA to be performed on an outpatient basis. Thirty-six girls and 41 boys aged between 11 weeks and 12 years (median age 40 months) with inconsistent behavioural-audiometric findings were examined. Frequency-following responses were searched for in flat fast response curves. BERA proved to be a very sensitive method compared with behavioural audiometry and was reliable even for children who are difficult to evaluate clinically, and for asymmetrical auditory thresholds. In conjunction with the standard pedaudiological test battery, BERA improves diagnostic accuracy and causes little disturbance as an outpatient procedure.

Audiometry, Evoked Response↗
PubMed1989

[Functional morphology of pulp tissue].

As compared with mesenchyme no genuine defense cells are developed in the tissue of the dental pulp and the nervous tissue. This is a further hint for the common development from ectoderm. The three dimensional meshwork of pulpa fibroblasts ("mesectoderm") is structured by elongated cell processes connected with each other by a variety of special cell junctions ("electronic cell coupling"). Metabolites from the microcirculation and neuropeptides from vegetative axons influence the activity of fibroblasts synthetizing groundsubstance. The meshwork of the groundsubstance has exclusion effects concerning molecules with a distinct molecular weight and charge. Thus a primitive defense system is established. With this the role of a newly described cell type of the dental pulp, the "lymphocytic pericyte" is discussed. Because of the poor capacity of the pulpa tissue for immunological reactions pathologically disorders may easily become chronically spreading their antigenic components throughout the body.

Adult↗
PubMed1988

[Rehabilitation of patients with hearing disorders using hearing aids and tactical hearing measures].

After a brief summary of the problems of rehabilitation of hearing-impaired subjects, the optimal conditions for rehabilitation with hearing aids are presented: a) The right timing is crucial. b) Optimal provision of hearing aids must be carried out in close co-operation between the patient, the hearing aid technician and the otolaryngologist. c) Easy handling of the hearing aid and the use of attachments must be guaranteed. d) The hearing-impaired person must be fully informed as to the extent and type of hearing loss. He/she must accept the affliction and know about the possibilities of rehabilitation. The patient's motivation is a pre-requisite for all further steps. e) The patients must learn tactical measures to make optimal use of their hearing ability in relation to their environment. Hearing tactics consist of hearing training and a change in the attitude of the hearing-impaired patients themselves and their attitude towards their surroundings.

Auditory Perception↗
PubMed1987

A new hearing aid variant. Preliminary evaluation.

An attempt was made to combine the advantages of a behind-the-ear (BTE) hearing aid (trouble-free use, powerful amplification, room for high-quality components, space for large energy source, use of extra equipment), with the advantages of the in-the-ear (ITE) hearing aid (improved intelligibility, improved directional hearing, improved signal/noise ratio). A BTE hearing aid was equipped with filters and provided with an external microphone. A first experiment, carried out in an anechoic chamber on KEMAR (Knowles Electronic Manikin for Acoustical Research), showed that directional variation of the frequency response of the hearing aid microphone was better in the new hearing aid than in the original BTE. A second experiment was carried out with a group of 6 normal-hearing persons concerning the frequency characteristic of sound transmission from twelve angles in the horizontal plane without a hearing aid, with a normal BTE aid, with the 'new aid', and with an ITE aid. The new instrument gave significantly better directional hearing than the original BTE aid. A clinical study will be started to verify and extend the experimental results obtained.

Computer Simulation↗
PubMed1987

[Sonography in cervical lymph node metastases].

The value of high resolution real time sonography for the detection of cervical lymph-node metastases in head and neck cancers was assessed in 118 histological proven cases. The accuracy of sonography (89%) proved to be superior to palpation (80%). In 9 patients a thrombosis of the internal jugular vein was detected. The ability of sonography to detect tumorous infiltration of the arterial vessel wall is discussed in 12 patients. Regarding possible artefacts, sonography is the only imaging modality which can solve this problem. Sonography should be performed preoperatively in all patients with malignant head and neck tumors for cervical lymph-node staging.

Carcinoma, Squamous Cell↗
PubMed1986

Uptake of natural and man-made radionuclides by lichens and mushrooms.

Due to the large absorbing surface of the mycelium that grows in the upper parts of the soil mushrooms take up higher amounts of 137Cs and 40K than lichens. Besides these nuclides only the long-lived radionuclides 125Sb and 60Co could be measured; but not the short-lived fission-products 144Ce, 95Zr and 95Nb which probably decayed before absorption into the mycelium. These nuclides, however, are present in lichens because of their surface structures which enable high foliar deposition. The 137Cs-content of lichens is probably due to absorption by the mycobiont and seems to be used to satisfy their potassium-requirements. Mushrooms on the other hand are characterized by a relatively stable potassium-content and a wide ranging 137Cs-content which depends on the availability in different substrates. Occasionally the natural radionuclides 238U and 226Ra could be detected in mushroom and lichen samples, showing no correlation with the natural radionuclide content of the soil.

Basidiomycota↗
PubMed1986

[High-resolution sonography after surgery of cystadenoma lymphomatosum of the parotid gland].

Clinical and sonographic examinations were carried out on 38 patients who had undergone excision of a parotid gland for adenolymphomas and the results were compared. In 23 of these patients (60%) sonography showed further tumours on the same or opposite side, or bilaterally. The incidence of multiple tumours is therefore significantly higher than has been assumed so far. In 76% of patients, sonography showed clinically occult cystadenoma lymphomatosum. Only 14% of tumours smaller than 12 mm were detected clinically. In four patients, tumours larger than 12 mm, but lying deep in the gland were missed on palpation. In view of the frequency of multi-local or bilateral tumours, sonography of both parotids should be performed if there is clinical suspicion of a parotid tumour.

Adenolymphoma↗
PubMed1986

[Significance of computerized tomography in middle ear diagnosis].

Due to the important improvement represented by the latest computed tomography (CT) technology in respect of detail and excellent contrast resolution normal and pathological structures of the inner and middle ear can be visualised. The clinical and diagnostic value of CT in comparison to standard x-rays and tomography is prospectively evaluated on the basis 74 patient examinations. Today CT is unsurpassed in the diagnosis of cholesteatomas and glomus tumours and ranks first among all imaging modalities. Chronic inflammatory diseases and deformities of the middle ear can be evaluated in most cases on the basis of standard x-rays and tomography. The importance of CT is primarily complementary, except in preoperative cases. Fractures should be visualised first via standard x-rays. In cases of questionable complications (e.g. tympanic or intracranial haematomas), CT should be the next step. Conventional tomograms are not necessary.

Adolescent↗
PubMed1985

[Sonography in salivary calculi--indications and status].

In 23 patients with sialolithiasis the value of real time sonography was investigated. The calculi were correctly diagnosed in 91% of the patients. 3 of 4 calculi could be localized in the main duct of the salivary gland. Because of the high accuracy and the possibility to detect non opaque stones, sonography should be performed, if on plain film the localisation of the calculi is questionable, before sialography is done. In sonolithotrypsy, sonography can be used to document the extraglandular localisation of intraductal calculi.

Humans↗
PubMed1985

[Value of ultrasound study in lymphomas of the neck].

In order to determine the value of high resolution ultrasonic procedures in the diagnosis of lymphomas of the neck, a comparative study of palpation, sonography and the surgical findings was undertaken. 42 patients were studied and 210 criteria evaluated. The error incidence was found to be 23.8% for palpation, 4.8% for the sonography and 1% for the combination of the two methods. The suprasonic procedure can detect a lymphoma from 5 mm. on, whereas palpation is only possible upward of 15 mm. Therefore, high resolution sonography enables a more precise evaluation and diagnosis of lymphomas of the neck. It facilitates the locating of the lymphomas during surgery and also allows the differentiation to the large vessels of the neck preoperatively. Thus, sonography of the neck is of high informative value there is no physical inconvenience or stress for the patient, and it is easy and quick to administer.

Adolescent↗