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Biomedical subjects

U Baumann

Publications and source records attributed to U Baumann.

At least 73 records · Page 4Linked to original sources
PubMed1993

[Do pulmonary changes appear after elective laparoscopic cholecystectomy?].

30 patients without history of pulmonary disease who underwent elective laparoscopic cholecystectomy were examined on the day before and on the 2nd day after operation. Investigations included physical examination, chest X-ray and a spirometry. In case of postoperative pathological findings the same examinations were repeated 14 days after operation. On the chest X-ray 5 patients had postoperative alterations which disappeared within 14 days. The spirometry showed a slight decrease of VC, FRC and FEV1 which after 2 weeks had almost regained normal values. Therefore we do not consider it necessary to perform routine respiratory prophylaxis in patients undergoing elective laparoscopic cholecystectomy.

Adolescent↗
PubMed1992

Crystal structure of cleaved equine leucocyte elastase inhibitor determined at 1.95 A resolution.

The crystal structure of active-site cleaved equine leucocyte elastase inhibitor, a member of the serpin superfamily, has been solved and refined to a crystallographic R-factor of 17.6% at 1.95 A resolution. Despite being an intracellular inhibitor with rather low sequence homology of 30% to human alpha 1-antichymotrypsin and alpha 1-proteinase inhibitor, the three-dimensional structures are very similar, with deviations only at the sites of insertions and few mobile secondary structure elements. The better resolution in comparison with the structures of other cleaved serpins allows a more precise description of the so-called R-state of the serpins.

Amino Acid Sequence↗
PubMed1992

Hypnotizability in bulimic patients and controls. A pilot study.

Various studies have indicated that bulimics are more easily hypnotized and dissociate more readily than control groups and patients with other eating disorders. A comparison is reported of 15 inpatients with bulimia nervosa (DSM III-R) with 15 subjects in a control group comparable in age and education. The instrument used was the Harvard Group Scale of Hypnotic Susceptibility/Form A (HSGHS:A), which includes 12 standardized test suggestions. The results show that bulimics have higher scores in hypnotizability than the control group. A method study (comparison of self-evaluation with a video recording) shows that this is a result of the behaviour itself and not of the answering pattern used by the subjects in the questionnaire. It is possible that differing expectations regarding the experiment may have influenced the results. Considerations concerning the increased ability of bulimics to dissociate as a causal factor versus an accompanying phenomenon of the disorder are discussed.

Adolescent↗
PubMed1992

Increase of glomerular filtration rate and renal plasma flow by insulin-like growth factor-I during euglycaemic clamping in anaesthetized rats.

Renal function was studied in anaesthetized rats receiving i.v. infusions of recombinant human insulin-like growth factor-I (IGF-I) under euglycaemic clamp conditions. IGF-I increased glomerular filtration rate up to 35% and renal plasma flow up to 100%, this increase being dose dependent with half-maximal stimulation at serum IGF-I concentrations of about 24 pmol ml-1. Renal vascular resistance was reduced up to 50%, filtration fraction decreased up to 30% and urine flow increased up to three fold while arterial blood pressure was unchanged. Renal haemodynamics were affected at serum IGF-I concentrations that did not stimulate total body glucose disposal during euglycaemic clamping. IGF-I seemed to regulate renal function through IGF-I receptors apparently independent of acute changes of glucose metabolism.

Animals↗
PubMed1991

Crystal structure of cleaved human alpha 1-antichymotrypsin at 2.7 A resolution and its comparison with other serpins.

The crystal structure of proteolytically modified human alpha 1-antichymotrypsin (ACT), a member of the serpin superfamily, has been solved by Paterson search techniques and refined to an R-factor of 18.0% at 2.7 A resolution with mean deviations from standard bond lengths and angles of 0.013 A and 3.1 degrees, respectively. The final model consists of 374 amino acid residues, 126 solvent molecules and five sugar residues. Asn70 could be identified unambiguously as a glycosylation site and Asn104 is probably also glycosylated. The structure of cleaved ACT is compared with cleaved alpha 1-antitrypsin (alpha 1 PI) and with plakalbumin, which are prototypical models for cleaved and intact serpins, respectively. Cleaved ACT is very similar to cleaved alpha 1 PI; in particular, it has strand s4A, which is liberated by proteolysis, inserted as the middle strand in beta-sheet A. ACT and alpha 1 PI differ locally only at sites of insertions, except at the segment s3C-turn-s4C, which is displaced by several angström units. This region of ACT is involved in DNA binding.

Amino Acid Sequence↗
PubMed1991

[Differential diagnosis of cystic ovarian tumors by determination of estradiol in cystic aspirate].

Since ultrasound is routinely used in gynecologic practice, cystic ovarian tumours are detected and, as a result, more unnecessary operations are performed. The aim of our study was, to determine the value of measurement of intracystic oestradiol (E2) in the differential diagnosis of simple cystic ovarian tumours. 30 patients, who underwent a laparotomy for cystic ovarian tumour, had prior measurements of E2 content of the cystic fluid. In 7 functional cysts, E2 was higher than 3,700 pmol/l and in the 23 neoplastic cysts, E2 level was lower than 1,200 pmol/l. Our results and the review of the literature suggest, that E2 content of the intracystic fluid may help to differ between functional and neoplastic cystic ovarian tumours.

Adult↗
PubMed1990

Structural transition of alpha 1-antitrypsin by a peptide sequentially similar to beta-strand s4A.

Crystal structure studies have shown that cleaved and intact serpins differ essentially in the topology of beta-sheet A. This is five-stranded in the intact molecules and six-stranded after cleavage by insertion of strand s4A whose C-terminus has become free [Löbermann, H., Tokuoka, R., Deisenhofer, J. & Huber, R. (1984) J. Mol. Biol. 177, 531-556; Wright, T. H., Qian, H. X. & Huber, R. (1990) J. Mol. Biol. 213, 513-528]. The structural transition is accompanied by changes in spectral properties and an increase in thermal stability. We show here that an N alpha-acetyl-tetradecapeptide with the amino acid sequence of strand s4A, residues 345-358 of human alpha 1-antitrypsin, associates with intact alpha 1-antitrypsin and forms a stoichiometric complex with properties very similar to cleaved alpha 1-antitrypsin. Complex generation has the characteristics of a folding process.

Amino Acid Sequence↗
PubMed1990

[Validity of potential support--a pilot study of myocardial infarct patients].

This investigation examines the validity of potential (anticipated) support as an indicator of social action. A comparison of anticipated support with received support in the past is problematic; other research variants have to be found. A comparison of two samples offers possible validation: asking one sample about the potential support, with regard to a possible crisis, and asking the second sample about actually received crisis support. This study examines received social support in a population of 30 myocardial infarction patients, and anticipated social support among 30 healthy individuals (on the assumption that they would suffer from a cardiac-infarct). The findings suggested that patients self-reported support values are lower than the expected support of the disease-free population. In particular, the healthy individuals expected support from their spouses and grown-up children. On the contrary the patients often name their doctors in this context. In general the findings suggested that the expected support with regard to an imagined crisis is a problematical indicator (validity problem). Alternative explanations are possible; the explanation that results are effects of patients perception bias is less likely.

Adaptation, Psychological↗
PubMed1989

Probing hairpin structures of small DNAs by nondenaturing polyacrylamide gel electrophoresis.

The influence of temperature on the electrophoretic mobility of small DNAs, capable of forming hairpin structures, is investigated under nondenaturing conditions. Three series of hairpin-forming DNAs containing different numbers of thymidine, deoxyadenosine, and deoxyguanosine residues in their loop, and an identical sequence in the helical region, are analyzed. All show enhanced electrophoretic mobility if they adopt the hairpin conformation. The same quantitative relationship between hairpin formation and increase in electrophoretic mobility is observed for all of the three series. The constancy of this increase suggests a dependence of electrophoretic acceleration on the length of the helical region. A possible application of nondenaturing electrophoresis is monitoring the hairpin/coil transition. Another possible application is the detection of dimers formed by partially self-complementary sequences. This dimer formation is detected for completely complementary DNAs, whereas sequences which might form imperfect double helices, especially those with three bulged-out nucleotides, prefer hairpin formation. The possible applications are experimentally approached and discussed.

DNA↗
PubMed1989

The refined 1.9 A crystal structure of human alpha-thrombin: interaction with D-Phe-Pro-Arg chloromethylketone and significance of the Tyr-Pro-Pro-Trp insertion segment.

A stoichiometric complex formed between human alpha-thrombin and D-Phe-Pro-Arg chloromethylketone was crystallized in an orthorhombic crystal form. Orientation and position of a starting model derived from homologous modelling were determined by Patterson search methods. The thrombin model was completed in a cyclic modelling-crystallographic refinement procedure to a final R-value of 0.171 for X-ray data to 1.92 A. The structure is in full agreement with published cDNA sequence data. The A-chain, ordered only in its central part, is positioned along the molecular surface opposite to the active site. The B-chain exhibits the characteristic polypeptide fold of trypsin-like proteinases. Several extended insertions form, however, large protuberances; most important for interaction with macromolecular substrates is the characteristic thrombin loop around Tyr60A-Pro60B-Pro60C-Trp60D (chymotrypsinogen numbering) and the enlarged loop around the unique Trp148. The former considerably restricts the active site cleft and seems likely to be responsible for poor binding of most natural proteinase inhibitors to thrombin. The exceptional specificity of D-Phe-Pro-Arg chloromethylketone can be explained by a hydrophobic cage formed by Ile174, Trp215, Leu99, His57, Tyr60A and Trp60D. The narrow active site cleft, with a more polar base and hydrophobic rims, extends towards the arginine-rich surface of loop Lys70-Glu80 that probably represents part of the anionic binding region for hirudin and fibrinogen.

Amino Acid Chloromethyl Ketones↗
PubMed1989

Successful pregnancy in advanced renal failure without dialysis.

We describe a successful pregnancy in a 22-year-old patient with advanced renal failure, who gave birth to a living boy in the 35th week of pregnancy. At the time of spontaneous delivery the mother had a serum creatinine of 851 mumol/l. No dialysis treatment had been instituted during this successful pregnancy.

Adult↗
PubMed1989

[Evaluation of the system of the Study Group of Methodology and Documentation in Psychiatry based on recent literature (1983 to 1987)--a review].

The present paper gives a review of German studies concerning the AMP and AMDP system that have been published since 1983. The test manual to the AMDP-system, published 1983, is complemented herewith. The following topics are discussed: Syndromes/scales on the basis of psychological and somatic outcomes, studies on reliability (especially interrater reliability); capability to differentiate diagnoses; comparison with other assessment instruments, especially biological parameters; results of several diagnoses (schizophrenia, affective disorders, depression etc.); range of application (psychopharmacological studies, diagnostic questions, etc.). The review points out that the AMDP system covers a very wide and elaborate range. Some topics are pointed out that would merit additional study.

Documentation↗
PubMed1989

[Compliance of children and adolescents with type 1 diabetes (juvenile diabetes mellitus)].

Compliance has a main influence on quality of metabolic control of juvenile diabetics and on prognosis in course of illness. This study examines specific problematic spheres in treatment of type-1-diabetics and tries to identify reasons for non-compliance behaviour. The study includes 60 type-1 diabetics between 10 and 16 years of age by a compliance-self-report questionnaire. Results show diet, self-control and parts of insulin-therapy to be problematic treatment components. Differential effects with regard to sex, age and duration of illness have been found. As main reasons for non-compliance, social circumstances, states of emotion, overcharge and lack of information have been identified.

Adolescent↗
PubMed1988

Interaction of DNA hairpin loops and a complementary strand by a triplet of base pairs.

Hypothesis of non-enzymatic recognition of primordial tRNA and mRNA precursors is experimentally approached. DNA hairpins containing a different number of deoxyguanosine residues in the loop are analyzed for their binding ability to a chemically fixed single-strand of oligo(dC). In presence of small Mg2+ concentration a hairpin with five dG residues in the loop is adsorbed to affinity matrix. Comparison of elution temperatures of hairpin oligonucleotides with those of single-stranded oligoguanylic acids with length of the loop indicates, that smallest loop able to bind forms a triplet of base pairs.

Adsorption↗
PubMed1988

Characterization of complex gramicidin monolayers by light reflection and Fourier transform infrared spectroscopy.

The reflectivities of monomolecular films of water-insoluble fatty alcohols and fatty acid methyl esters are measured at the air/water interface. A correlation between chain length and reflectivity of the monofilm is established which agrees with calculated values derived from a theoretical model. The correlation is used to estimate thickness of a monolecular film of gramicidin A. Fourier transform infrared (FTIR) spectroscopy is applied to transferred mixed layers of ion-channel-forming gramicidin A and dioctadecyldimethylammonium bromide in order to evaluate the structure of gramicidin. Transfer conditions for these monofilms are elaborated. Results of the reflection method and FTIR spectroscopy demonstrate that gramicidin exists as double-stranded beta-helix inside the monolayer at a lateral pressure similar to that found in biomembranes.

Fourier Analysis↗
PubMed1987

Complexes of DNA hairpins and a single-stranded oligonucleotide detected by affinity chromatography and mung bean nuclease cleavage.

The emergence of a simple translation device consisting of an assembler strand (primordial mRNA) and RNA hairpins (primordial tRNA) is presumed to be an important step leading to the origin of life. The assumption of a non-enzymatic interaction of primordial tRNA and mRNA is experimentally approached. DNA hairpins containing five or more adenosine residues in the loop are able to bind to complementary oligonucleotides covalently bound to cellulose. The exact number of base pairs formed between the hairpins and the assembler strand is determined by two methods applied to DNA hairpin/assembler complexes. The melting temperature of a complex is measured and the cleavage pattern by nuclease from mung bean is determined. The loop of the smallest hairpin able to bind consists of five adenosine residues and only three base pairs are formed. This supports the idea of a primordial recognition similar to the contemporary codon-anticodon interaction.

Biological Evolution↗