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Biomedical subjects

G Hertel

Publications and source records attributed to G Hertel.

At least 19 recordsLinked to original sources
PubMed2000

Health circles for teleworkers: selective results on stress, strain and coping styles.

Telework is decentralized computer-mediated performance of work activities at a location distant from the employing organization. In order to improve well-being at such remote workplaces, we developed a health circle (HC) concept for teleworkers. Three HC sessions were conducted with a total of 17 teleworkers from diverse organizations and branches. The sessions were moderated by a professional facilitator, while the participants selected the discussion issues. Typical issues were technical problems at the home-based computer, time management, communication with supervisors, colleagues and customers, and feelings of isolation from the main company. Besides discussing these stress factors, participants developed concrete coping strategies based on the exchange of experiences and additional informational input by external experts. Process evaluation at the end of each meeting revealed that participants found the exchange of personal experiences and the informational input during the HCs very helpful, as well as the common development of coping strategies. Moreover, a questionnaire 2 months after the last HC session revealed that participants reported significantly more positive changes in typical stress factors than teleworkers in a control group. The implications of these results for preventive and corrective strategies of telework design are discussed.

Analysis of Variance↗
PubMed2000

Motivation gains in performance groups: paradigmatic and theoretical developments on the Köhler effect.

In contrast to many demonstrations of social loafing, relatively few studies have documented group motivation gains. One such exception was O. Köhler's (1926, 1927) finding that team members working together did better at a taxing persistence task than would be expected from their individual performances, particularly when there was a moderate discrepancy in coworkers' capabilities. In Experiment 1, we developed a paradigm within which Köhler's overall motivation gain effect could be replicated, although the discrepancy in coworkers' capabilities did not moderate these motivation gains (after statistical artifacts were taken into account). Experiment 2 indicated that this motivation gain occurred under conjunctive but not under additive task demands, suggesting that the instrumentality of one's contribution to valued outcomes is a more likely explanation of the Köhler effect than social comparison processes.

Cooperative Behavior↗
PubMed1999

In vivo and in vitro CT analysis of the occiput.

Arguments concerning the best procedure for occipito-cervical fusion have rarely been based upon occipital bone thickness or only based on in vitro studies. To close this gap and to offer an outlook on preoperative evaluation of the patient, 28 patients were analysed in vivo by means of spiral CT. Ten macerated human skulls were measured by means of CT and directly. Measurements were taken according to a matrix of 66 points following a grid with 1 cm spacing based upon McRae's line. Maximum thickness in the patient group was met 4 cm above the reference plane in the median slice (11.87 mm; SD 3.41 mm) and 5 cm above it in the skull group (15.85 mm; SD 1.81 mm). Correlation between CT and direct measurements was good (91.79%). Intra-individual discrepancies from one side to the respective point on the other side are common (difference > 1 mm in 60%). Judging areas suitable for operative fixation using the 10% percentile value (6.68 mm for the maximum value of 11.87 mm) led to the conclusion that screws should only be inserted along the occipital crest in an area extending from 1.5 cm above the posterior margin of the foramen magnum to the external occipital protuberance (EOP). At the level of the EOP screws may also be inserted up to 1 cm lateral of the midline. A reduction of screw length to 7 mm (9 mm for the EOP) is proposed. Preoperative evaluation of the patient should be carried out by spiral CT with 1 mm slicing and sagittal reconstructions.

Adolescent↗
PubMed1995

Aspiration complicating bronchopulmonary dysplasia.

The purpose of this study was to study the relationship of aspiration with ongoing respiratory difficulties in infants with bronchopulmonary dysplasia (BPD). Twelve infants with BPD were identified out of 314 children who had flexible bronchoscopy between 1987 and 1990; 11 of 12 had bronchoalveolar lavage (BAL). The lipid index (LI) was used to quantify the degree of lipid-laden macrophages in the BAL fluid as a marker of aspiration. The age range at the time of bronchoscopy was 3 months to 5 years. The LI was considered positive in 6 of 11 subjects. A pH probe study was done on seven subjects with concordant findings in five. Other findings included dynamic or structural airway abnormalities in 10 of the 12 subjects. These data suggest that aspiration frequently is associated with BPD in addition to the previously recognized dynamic and structural airway problems. The predisposition to gastroesophageal reflux and laryngeal injury probably accounts for the increased aspiration risk in children with BPD.

Bronchoalveolar Lavage Fluid↗
PubMed1991

Immunologic relatedness of extracellular ligninases from the actinomycetes Streptomyces viridosporus T7A and Streptomyces badius 252.

Four isoforms of the extracellular lignin peroxidase of the ligninolytic actinomycete Streptomyces viridosporus T7A (ALip-P1, P2, P3, and P4) were individually purified by ultrafiltration and ammonium sulfate precipitation, followed by electro-elution using polyacrylamide gel electrophoresis. Three of the purified peroxidases were compared for their immunologic relatedness by Western blot analysis using a polyclonal antibody preparation produced in rabbits against pure isoform P3. The anti-P3 antibody was also tested for its reactivity towards a lignin peroxidase from the white-rot fungus Phanerochaete chrysosporium and another ligninolytic actinomycete Streptomyces badius 252. Results showed that peroxidases ALip-P1 through ALip-P3 are immunologically related to one another. The peroxidases of S. badius, but not the peroxidase of P. chrysosporium, also reacted with the antibody, thus indicating that the lignin peroxidases of S. viridosporus and S. badius are immunologically related. Based upon its specific affinity, lignin peroxidase isoform ALip-P3 of S. viridosporus was readily purified using an anti-P3 antibody affinity column.

Blotting, Western↗
PubMed1990

Cloning and expression of a lignin peroxidase gene from Streptomyces viridosporus in Streptomyces lividans.

A lignin peroxidase gene was cloned from Streptomyces viridosporus T7A into Streptomyces lividans TK64 in plasmid pIJ702. BglII-digested genomic DNA (4-10 kb) of S. viridosporus was shotgun-cloned into S. lividans after insertion into the melanin (mel+) gene of pIJ702. Transformants expressing pIJ702 with insert DNA were selected based upon the appearance of thiostrepton resistant (tsrr)/mel-colonies on regeneration medium. Lignin peroxidase-expressing clones were isolated from this population by screening of transformants on a tsr-poly B-411 dye agar medium. In the presence of H2O2 excreted by S. lividans, colonies of lignin peroxidase-expressing clones decolorized the dye. Among 1000 transformants screened, 2 dye-decolorizing clones were found. One, pIJ702/TK64.1 (TK64.1), was further characterized. TK64.1 expressed significant extracellular 2,4-dichlorophenol (2.4-DCP) peroxidase activity (= assay for S. viridosporus lignin peroxidase). Under the cultural conditions employed, plasmidless S. lividans TK64 had a low background level of 2.4-DCP oxidizing activity. TK64.1 excreted an extracellular peroxidase not observed in S. lividans TK64, but similar to S. viridosporus lignin peroxidase ALip-P3, as shown by activity stain assays on nondenaturing polyacrylamide gels. The gene was located on a 4 kb fragment of S. viridosporus genomic DNA. When peroxidase-encoding plasmid, pIJ702.LP, was purified and used to transform three different S. lividans strains (TK64, TK23, TK24), all transformants tested decolorized poly B-411. When grown on lignocellulose in solid state processes, genetically engineered S. lividans TK64.1 degraded the lignocellulose slightly better than did S. lividans TK64. This is the first report of the cloning of a bacterial gene coding for a lignin-degrading enzyme.

Cloning, Molecular↗
PubMed1989

[MRT in primary and tumor-induced syringomyelia].

The MRI findings in 26 patients with primary syringomyelia and eight patients with a syrinx due to an intramedullary tumour were studied retrospectively. In general, the syrinx in the tumour cases resembled the appearance of primary syringomyelia. However, a specific and sensitive sign of tumour-induced syringomyelia was irregularity of the spinal cord close to the tumour (eight cases of eight), eccentric position of the lumen (seven of eight), and a diffuse increase of signal intensity on T2-weighted images (eight of eight). Primary syringomyelia also showed increased signal intensity on T2-weighted images outside the lumen, but this was closely related to the cavity. The use of Gd-DTPA improved demarcation of the tumour from the syrinx in all cases. Widening of the spinal canal and ectopia of cerebellar tonsils was a typical finding in primary syringomyelia. MRI proved a reliable method for distinguishing between a tumour-induced syrinx and primary syringomyelia.

Adolescent↗
PubMed1989

[Anesthesia-induced changes in the preload-dependent circulatory reactions in patients with coronary heart disease].

The influence of preload changes (table tilt) on the hemodynamic regulation before and after induction of neuroleptanalgesia was studied in 31 patients with coronary heart disease. The induced preload changes are balanced in the awake patient for the maintenance of normal arterial pressure by regulation of stroke volume and peripheral vascular resistance. This regulation does not exist after induction of anaesthesia. Splitting the patients into sub-groups with good or poor left ventricular function, different ventricular function curves were obtained before and after the induction of anaesthesia. The pharmacologic and ventilatory reasons for the changed regulation of circulation are discussed. For investigations into hemodynamic changes produced by intervention in anaesthesia and intensive therapy, it is recommended to define more exactly the cardiovascular status of patients and the study conditions.

Coronary Disease↗
PubMed1988

Multiple sclerosis: diagnostic value of computerized tomography with delayed scanning after a double-dose of contrast medium in comparison with other diagnostic tests.

In 63 cases of clinical definite or suspected MS we compared the results of CSF analysis, VEP, BAEP, CT scanning without and after double dose contrast, in 17 cases also those of MRT. We found that CSF analysis had the highest rate of abnormal findings, followed by MRT. VEP and CT with double dose contrast showed similar sensitivity, while BAEP and CT without contrast had disappointing results. We think that CT with delayed scanning after double dose contrast can be a very useful investigation in early and doubtful cases of MS, until MRT will become a more widespread and less expensive investigation.

Adult↗
PubMed1988

Characterization of an extracellular lignin peroxidase of the lignocellulolytic actinomycete Streptomyces viridosporus.

Previously we reported production of an extracellular lignin-inducible peroxidase by Streptomyces viridosporus (M. Ramachandra, D.L. Crawford, and A.L. Pometto III, Appl. Environ. Microbiol. 53:2754-2760, 1987). This peroxidase was shown to oxidize 3,4-dihydroxyphenylalanine, 2,4-dichlorophenol, homoprotocatechuic acid, caffeic acid, and N,N,N',N'-tetramethylphenylenediamine and was found in higher than normal levels in strains enhanced for lignocellulose degradation. In the present study, we used a pure extracellular enzyme preparation with high peroxidase isoform P3 activity to oxidize lignin substructure model compounds of both the 1,2-diaryl propane and arylglycerol-beta-aryl ether types and containing C alpha-carbonyl and C alpha-hydroxyl groups. The reactions were monitored by gas chromatography-mass spectrometry and high-pressure liquid chromatography techniques. In the presence, but not the absence, of hydrogen peroxide, the enzyme preparation catalyzed C alpha-C beta bond cleavage in the side chains of the diaryl ethers 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)propane-1,3-diol (I) and 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)propan-1-one (II) and the diaryl ethane 1-(4-methoxyphenyl)-2-(phenyl)ethan-1-one (III). Rapid hydrogen peroxide consumption was observed when the enzyme preparation was added to either milled corn lignin or lignocellulose. Additional characterizations showed that this enzyme is a heme protein (Soret band, 408 nm) and a major component of the ligninolytic system of S. viridosporus T7A. This is the first report of a lignin peroxidase in a bacterium. We have designated this new lignin peroxidase as ALiP-P3.

Biodegradation, Environmental↗
PubMed1988

Double-blind crossover study comparing sodium cromoglycate, reproterol, reproterol plus sodium cromoglycate, and placebo in exercise-induced asthma.

Sixteen patients were included in the analysis of this double-blind crossover study comparing the effect of sodium cromoglycate, reproterol, sodium cromoglycate plus reproterol, and placebo in exercise-induced asthma. Both the sodium cromoglycate and the reproterol-containing treatment significantly inhibited exercise-induced asthma. The best protection is effected by the combination of sodium cromoglycate and reproterol. A synergistic effect of both medications could not be confirmed statistically so that their combined effect is simply additive.

Administration, Inhalation↗
PubMed1986

[Neurologic symptoms in Legionella infection. A case report of the clinical aspects and diagnosis of legionellosis].

In patients with infection from Legionella pneumophila, it must be taken into consideration that the nervous system may be involved. This involvement can precede the pneumonia by several days. Headache, acute mental status changes and cerebellar dysfunctions are the most common neurological symptoms. In the case reported, extrapyramidal disturbances were also observed that are rarely found in association with Legionella infection. There are grounds for the assumption that Legionella toxins cause impairment to the nervous system. The neurological symptoms are not specific enough to allow differentiation of this infection from pneumonia of other etiologies.

Athetosis↗
PubMed1985

[Magnetic resonance tomography in syringomyelia].

Thirteen patients with a clinical diagnosis of syringomyelia were examined by nuclear tomography (0.35 T magnet) in the spin-echo mode. In all thirteen patients, the T1 images (SE 400/35) showed a longitudinal cavity with a signal intensity of CSF. The shape and extent of the syrinx could be adequately demonstrated in 12 of the 13 examinations. Downward displacement of the cerebellar tonsils was seen in eight cases. The examination took between half and one hour. Advantages of magnetic resonance tomography (nuclear tomography) include the absence of artifacts, images in the line of the lesion and its non-invasiveness.

Adult↗