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Biomedical subjects

W Meissner

Publications and source records attributed to W Meissner.

At least 55 records · Page 3Linked to original sources

Transcription factor IIA stimulates the expression of classical polIII-genes.

Protein fractions containing TFIIA, a transcription factor known to be involved in transcription initiation by RNA polymerase II and 5'-regulated polymerase III genes (e.g. U6), were tested for their role in in vitro transcription of classical pol III genes. These fractions were shown to stimulate a basal transcription system, reconstituted from highly purified fractions hTFIIIB and hTFIIIC. We demonstrate that this stimulating activity isolated from HeLa cells coelutes over at least six chromatographic steps with hTFIIA. Moreover the native molecular mass and the stability of this activity against heat treatment are comparable to those of hTFIIA. Finally we show that recombinant TFIIA from Saccharomyces cerevisiae can substitute for the human factor in pol III transcription in vitro which proves that TFIIA is also involved in the efficient expression of classical pol III genes.

Humans↗

[Experiences with high-frequency hearing tests in the selection of personnel for noise occupations].

A total of 181 persons aged between 16 and 18 were checked fully audiometrically (conventional and high-frequency audiogram). Dates of history about hereditary hearing damage, own ear diseases, noise exposure during frequent visits to discothecs or usage of Walkman etc. were ascertained by questionnaires. The evaluation of the results was carried out with the help of discrimination analysis allowing a multi-dimensional classification. As a result there could be made a sure discrimination analytic separation in persons with ear diseases during their childhood, when the high frequencies from 10 to 15 kHz were taken in. Thus the damage of the inner ear was to be found mainly on the base of the cochlea. Also in cases of hereditary influence there was to be seen a clear deminution in the high frequency area. The group of persons, who regularly went to discos (more than three times a month) as well as the group often using Walkman revealed a sure separation, when the high frequencies above 8 kHz were considered in the calculation. Altogether there could be seen an early damage more clearly in the high frequency area after ear diseases in childhood as well as a result of sound overloading than in conventional hearing area.

Adolescent↗

Elevated serum diiodotyrosine (DIT) in severe infections and sepsis: DIT, a possible new marker of leukocyte activity.

Ether link cleavage (ELC) of T4 yielding diiodotyrosine (DIT) has recently been shown in vitro to be the major pathway of T4 metabolism in phagocytosing leukocytes. To evaluate this pathway in vivo and the possible clinical relevance of DIT measurements in diseases with increased leukocyte activity, radioimmunological studies on serum levels of DIT and other thyroid parameters were performed in 125 critically ill patients classified into 3 groups with bacterial infections according to the severity of infection and 1 group without infections. While the pattern of iodothyronine and TSH levels typical for severe nonthyroidal disorders, i.e. decreased total T3 and elevated rT3, normal or decreased total T4 and TSH, and normal free T4, was found in all four groups of intensive care patients studied, elevated serum DIT was observed only in those patients whose clinical course was complicated by severe bacterial infections. Serial measurements revealed a close temporal connection between the infection phase and increased DIT levels. Median values and 16th to 84th percentile ranges (in parentheses) of serum DIT (normal range, 0.02-0.55 nmol/L) were as follows: sepsis, 1.38 (0.32-5.14); severe nonsystemic infections such as peritonitis and abscesses, 3.84 (0.24-17.2); moderate infections such as pneumonia and tracheobronchitis, 0.44 (0.18-1.16); and critical illness without infections, 0.14 (0.08-0.30) nmol/L. These elevations of circulating DIT could neither be correlated with changes in renal function nor attributed to drug effects. The results of the present study do not allow any definitive conclusions to be made about the mechanisms underlying the phenomenon of increased serum DIT levels in infections. Apart from this open question, DIT appears to be a relatively specific serum parameter for the presence and course of severe bacterial inflammations. Its measurement could provide useful clinical information, particularly for monitoring the time course of deep-seated infections.

Bacterial Infections↗

Physical and immunological characterization of human transcription factor IIIA.

Human transcription factor IIIA (htFIIIA), specifically required for transcription of the gene for 5S ribosomal RNA has been characterized with respect to some of its physical, immunological and functional properties. TFIIIA from HeLa cells, which selectively binds 5S RNA, is a monomer of approximately 35 kDa with a Stokes' radius of approximately 2.65 nm and a sedimentation coefficient of approximately 2.8 S. These values indicate that the human protein is of rather globular shape and hence diverges not only in molecular mass but also in most of the molecular properties from its highly asymmetric counterpart in Xenopus laevis oocytes. By raising specific polyclonal antibodies against hTFIIIA it was shown in Western immunoblots that there was no cross-reaction between anti-hTFIIIA antibodies and the amphibian protein. Conversely, monoclonal antibodies against three domains of X. laevis TFIIIA antibodies and the amphibian protein. Conversely, monoclonal antibodies against three domains of X. laevis TFIIIA did not cross-react with the human transcription factor. The polyclonal antisera raised against hTFIIIA specifically neutralized binding of the human transcription factor to 5S DNA and abolished in vitro transcription of 5S RNA but these antibodies were unable to inhibit 5S RNA synthesis in cellular extracts from Xenopus, Drosophila or yeast cells. Finally, the species variation of TFIIIA could be substantiated by electrophoretic mobility shift assays revealing preferential binding of hTFIIIA to the homologous 5S RNA gene.

Animals↗

[The accuracy of subjective determination of auditory threshold in the range of 0.5 to 18.0 kHz using different sound transducer systems].

This paper reports on the degree of accuracy of determinations of hearing threshold in the 0.5 to 18 kHz range. As far as possible, these hearing thresholds were compared with those of ISO 389. Furthermore, the study compared determinations of hearing thresholds measured on different days. Reproducibility was very good, particularly of the high-frequency thresholds. The two types of sound transducers used here (a quasi-free field system developed by the authors and a pair of professional headphones) showed an identical transmission of frequencies and good reproducibility of the results of measurements.

Adult↗

[Manifestations of inactivity in unilateral hearing aid management of patients with a high degree of hearing loss].

Concluding from audiometrical practice using hearing aids unilaterally we could find an inactivity of the unused contralateral ear. We have investigated if it is possible to measure this inactivity by common psychoacoustic methods. We tested 92 persons with advanced combined hearing loss. We had to state that the inactivity is not measurable by mean tone hearing loss according to HAIC (0.5, 1 and 2 kHz), the percentage hearing loss according to Fowler-Sabine, the percentage of hearing loss calculated by speech-audiogram according to Boenninghaus and Röser 1973 and the value of hearing loss for speech (a1). It is only a big discrimination loss that points to the presence of inactivity. The discrimination loss was compared in two groups concerning "used" and "unused" ears. We could clearly measure the biggest discrimination loss in the group of unused ears. The clinical consequences were discussed.

Attention↗

[Assessment of social hearing with a questionnaire in relation to average hearing loss].

In 86 patients with sensorineural hearing loss we checked if the measuring results obtained by conventional audiometric procedures correlate with the subjective impression of hard hearing ascertained via a special questionnaire. For this purpose we compared the average hearing loss (500, 1000, 2000 Hz) of the puretone audiogram with the results obtained via the questionnaire developed by v. Wedel and Tegtmeier for assessing the social hearing handicap (SHH). We can see that there is good correlation between the SHH index values and the average hearing loss with frequencies of 0.5, 1.2 kHz in pancochlear perception hearing loss, whereas in patients with basocochlear perception hearing loss the SHHI cannot be calculated with the help of the puretone audiogram, nor will a widening of the frequency range up to 6 kHz lead to a better correlation between the average hearing loss and SHHI.

Aged↗

[Distorted Freiburg Speech Test].

In 107 patients with different types of hearing loss (air conduction, sensorineural and combined) we ascertained the monaural discrimination loss of monosyllables with the help of the normal and distorted Freiburg speech test. It was evident that the quotient obtained from the measured discrimination is a very good and useful measure to characterise the ability to analyse the peripheral hearing system. Compared with normal hearing individuals and patients with air conduction hearing loss or combined loss of hearing, persons with perception hearing loss show a much greater and more divergent quotient. The discrimination of distorted speech depends more on age than that of normal speech; however, it is considerably reduced from the sixth decade of life onwards. The distortion test offers the expertising the possibility of improved assessment of speech discrimination by workers in a noisy environment in case of unfavourable hearing conditions, but it is also of considerable importance in fitting hearing aids and in the diagnosis of acoustic tumours.

Adolescent↗

A clinical and pathological staging system for soft tissue sarcomas.

A system for staging the clinical status of patients with soft tissue sarcomas is presented, based on the clinical characteristics of the primary tumor (size, extension), the involvement of lymph nodes, the presence of metastases, and the grade of the tumor. This represents the TNM system with grade of tumor (G) added. The system evolved was based on examination of 1215 cases of 13 types of soft tissues sarcomas, primarily in the extremities (fibrosarcoma, liposarcoma, etc.). Nine stages are described, and they are correlated with survival in the cases reviewed. The staging system now can be used for case evaluation for therapy determination and for intercomparison of series of patients as to incidence of different kinds of tumors, effects of treatment, and survival.

Adult↗

[A proposal for a method of precalculation of hearing losses (author's transl)].

Three well-known procedures for the determination of auditory noxiousness from noise level and time of exposure are discussed and the theoretically expected 4 kHz hearing losses in selected textile and metal workers exposed to noise are compared with the measured PTS values. The method after Kraak showed the best correlation between noise load and hearing loss. On the basis of these results a noise level table with intervals of 2-3 dB between 85 and 110 dB(A) was developped, from which the noise load after 1 to 40 working years can be read off in figures. After evaluation of 256 noise opinions a method for determination of maximum noise doses is proposed. The table presented may be used in the determination of characteristic coefficients.

Adult↗

[The effect of selenium and fluorine with respect to caries and toxicity to Osborne-Mendel-rats (author's transl)].

Two experiments carried out with one hundred rats from the Osborne-Mendel-strain were supposed to prove the influence of selenium-containing-drinking-water on caries. The animals were divided into five experimental groups of twenty rats each. Selenium was tested in different doses as an addition to drinking-water in shape of Na2SeO4, as well as in combination with a tooth-paste containing NaF.-Its toxicity was to be determined by the water consumption, the mortality and above all by the body weight of the animals at the end of the test. During the first experiment three groups received Na2SeO4 in doses of 1, 5 and 10 ppm in the drinking water and the cariogenic diet Stephan 580 as food. Two other groups served as control, one receiving the cariogenic diet Stephan 580 and the other one getting the normal breeding diet. The analysis of variance carried out for the assessment of caries and the test of SCHEFFE only show a different attack concerning those groups, receiving the cariogenic diet and the control group fed with the breeding diet Altromin R. Nine of the 40 animals of the groups that had received the selenium doses of 5 and 10 ppm did not survive the experiment. The average value of the water consumption and the body weight of the animals of the selenium group was below the average of the remaining groups, which points out a strong toxicity of Na2SeO4. In regard to the water consumptions, however, one cannot exactly define, whether it is an effect of the selenium of the cariogenic diet. All groups of the second experiment received the cariogenic diet Stephan 580; two of them got Na2SeO4 in doses of 4ppm within their drinking water. The molars of the lower jaws of one of these group were brushed with a tooth-paste containing NaF. The molars of the other group were treated with a paste, serving as a placebo. Two other groups were provided each with the paste containing fluorine and the paste serving as a placebo, but without selenium in their drinking water. Furthermore 20 animals were used as a control group. The analysis of variance showed the widely known protective effect of the fluorine by the statistically significant different distribution of the caries. Comparing those two groups, whose drinking water contained Na2SeO4 with the two other groups whose molars were treated with the paste containing fluorine and the one serving as a placebo respectively, we may conclude, that Na2SeO4 has no influence on the protective effect of the fluorine. A comparison of the group treated with the paste serving as a placebo with the control group shows, that the tooth-brushing obviously has no great effect. In respect to the body weight at the end of the experiment one cannot demonstrate a clear effect using the linear contrast of SCHEFFE, and there also is no infleunce of selenium on the total water consumption, which coincides with the results of the first experiment. The two experiments have shown that Na2SeO4 is toxic in the doses applied...

Animals↗

[Limit of measurement of middle ear impedance (author's transl)].

The air volume enclosed in the acoustic duct is considered to be one of the causes of the bad reproductibility and the great scattering of measurement results of middle ear impedance. Therefore this volume was measured with ten subjects (20 ears) and the measured values of impedance were corrected. A procedure for determining the volume between the occlusion of the external canal and the ear-drum is described. The difficulties of carrying out this procedure are pointed out. Because of the volume determination for series examinations the measurement of the value of the impedance change as a criterion for individual resistance to noise of persons exposed to pulse noise involves great efforts and is therefore considered to be an inappropriate method as long as the indicated difficulties with measuring techniques continue to exist.

Air↗