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Biomedical subjects

W Hahn

Publications and source records attributed to W Hahn.

At least 19 recordsLinked to original sources
PubMed1991

T7 infection-dependent selective expression of cloned genes in P1-lysogenic Escherichia coli.

Expression systems based on the selective transcription of genes cloned behind a T7 promoter, by T7 RNA polymerase, display a non-negligible basal expression when the T7 RNA polymerase gene is present within the host organism before induction of the system. This is a problem, especially for cloning and controlled expression of genes toxic to the host organism. We have circumvented this problem by taking advantage of abortive T7 infection of E. coli (P1), in the course of which T7 RNA polymerase is synthesized but bacterial growth is not quantitatively impaired. We have tested this system with three reporter genes, the 6-phospho-beta-galactosidase gene of Staphylococcus aureus, the luciferase operon of Vibrio harveyi, and the rabbit beta-globin gene; we have found very low basal levels, while, upon T7 infection, transcription is at least as efficient as in other in vivo T7 RNA polymerase systems in use.

Animals↗
PubMed1991

[Acute cor pulmonale as a sequela of tumor embolism].

It is reported on a 22-year-old female patient with a chondroplastic osteosarcoma in the sacrum in whom in the course of her disease a massive embolism due to a tumour developed under the clinical picture of an acute pulmonary embolism. The clinical tentative diagnosis of a massive pulmonary embolism was confirmed by means of lung perfusion scintigram and pulmonary angiography. All efforts for a rapid recanalisation of the left pulmonary trunk by means of mechanical alteration, use of balloon catheter and subsequent thrombolysis were without success. Pathologo-anatomically a recurred tumorous thrombus embolism with an extensive pulmonary infarction in the left inferior lobe of the lung was found. The incidence as well as diagnostic viewpoints of embolisms due to tumour are discussed.

Adult↗
PubMed1990

[Early and late results after local streptokinase administration in massive lung embolism].

In a total number of 44 patients with acute massive lung embolism 42 patients survived the acute phase. The treatment was carried out by thrombolysis with streptokinase. The application was performed as near to the thrombus as possible, in several patients after preceding balloon dilatation or also as multiphase treatment using urokinase. We altogether obtained favourable early results concerning the recanalisation got as well as also with regard to the clinical state and the subjective condition, particularly for patients with single acute occurrence and a latency period of less than 72 hours up to the beginning of the treatment. In follow-up examinations of 17 patients after more than 9 months (on an average after 32 months) without exception a good and further on ameliorated condition, respectively, was stated. Under long-term anticoagulation with phenprocoumon no recidivation embolisms appeared. Ergooxytensiometric investigations had as result a clear to extreme hypoxia on exertion as limiting factor for 12 out of 17 patients. Apart from this the majority of the patients a hyperdynamic regulatation of the circulation was to be observed. Therefore the ergooxytensiometry is recommended for the judgment of the result of the treatment as to the demandable exercise tolerance.

Adult↗
PubMed1990

[An experiment on the theory of visual motion perception].

Two classes of theories of motion perception were studied: correlation and gradient models (in the sense of D. Marr). Random-dot kinematograms with a shifted square were presented to subjects, and the 80% threshold for detection of correct direction of movement was determined. Correlation models predict scale invariance, that is, a constant shift measured in units of texture elements of the translated pattern in spite of a geometric magnification. This was refuted for all subjects. The increase of the recognizable translation with the area of the translated form was verified except for the patterns with the largest texture elements (8 minutes of arc). This prediction, however, is not very specific for competing theories. Gradient models are not yet fully specified, and they contain some free parameters. They cannot be tested strictly, but there exist reasonable numerical parameter values by which our data can be satisfactorily explained.

Adult↗
PubMed1989

[Dose-reduced antihypertensive agents--use in complex nonmedicamentous therapy of hypertension].

In order to estimate the influence of a non-medicamentous therapy (CNT) on the consumption of medicaments and coronary risk in high blood pressure 73 hypertensives of a medicamentously stabilized CNT-group were examined in comparison to a group of the same size of patients with hypertension who were managed exclusively medicamentously for behaviour of blood pressure, need of antihypertensive drugs and changes of hypertension-associated risk factors. After an exactly controlled 6-month treatment hypertensives with additionally recommended far-reaching CNT showed an economization of medicaments by scarcely the half in comparison to the reference group. By means of suitable control methods a causal non-medicamentously conditioned decrease of blood pressure could be excluded. A different need of antihypertensive drugs was simulated by the exacter intake of medicaments in the index-patients. Notwithstanding the metabolic effects of the additional therapy have induced a positive change of atherogenic lipids. The examinations indicate in general the difficulty of the judgement of efficacy of non-medicamentous therapeutic measures in connection with a rational dose-reduced long-term therapy with antihypertensive drugs.

Adult↗
PubMed1988

[Results of a 2-year intervention for the modification of atherosclerosis precursors in school children].

801 children aged 10-11 years were examined in 1984, before an allocation in two groups (intervention vs. control). The scope of the intervention was to modify mean values of blood pressure, total cholesterol and smoking through relevant modification of knowledge and behavior. An intermediate assessment, conducted 2 years after the first exam, showed better knowledge regarding cardiovascular diseases and more sport practice in the intervention group, although smoking habits were only slightly modified. Diet, body weight, blood pressure and blood lipid levels did not show any significative differences. The study is now ongoing.

Anthropometry↗
PubMed1985

Cloning and sequence of DNA encoding structural proteins of the autonomous parvovirus feline panleukopenia virus.

Approximately 80% of the genome of feline panleukopenia virus was cloned into pBR322. This DNA included the transcription unit for the major viral mRNA species. The nucleotide sequence of the cloned portion of the genome was determined. Comparison of the feline panleukopenia virus sequence with the sequences of the parvoviruses minute virus of mice and H-1 revealed considerable homology between the three viruses on both the nucleic acid and protein levels. Based on this homology, a model for the generation of the two size classes of viral structural proteins (VP1 and VP2') is proposed.

Amino Acid Sequence↗
PubMed1983

Long term results with intraosseous implants: a questionnaire-based assessment.

The results of an FDI questionnaire-based survey involving dentists from five countries reporting on 507 implants were compared with those of similar surveys on implantations conducted by the American Dental Association in 1977 and subsequent years. There were questions on retention time, materials used and types of implants; of the 1024 recorded implants, the loss rate was calculated at 16.5 per cent. This rate was compared with those found in objective follow-up investigations reported in the literature (total 695 implants) and a realistic loss rate of approximately 16 per cent, was confirmed.

Data Collection↗