Search PubMed⌕ Search

Biomedical subjects

R Rudolph

Publications and source records attributed to R Rudolph.

At least 307 records · Page 17Linked to original sources
PubMedDate not supplied

Fibroblast senescence in pressure ulcers.

Pressure ulcers appear as localized chronic wounds in the middle of normal functioning skin. This study focuses on pressure ulcer fibroblasts cultured from the ulcer bed, ulcer margin, and normal, nonulcerated skin adjacent to the wound. From these areas we show that pressure ulcer fibroblasts become prematurely senescent. Verification of senescence was based on failure of cell populations to undergo a 0.5 population doubling after 1 week in culture, light microscopic appearance of late-passage senescent cells in culture, light microscopic verification of senescence in vivo and in vitro by anti-terminin staining, and ultrastructural identification of senescent fibroblasts by anti-terminin colloidal gold labeling. Although not all ulcer fibroblasts are senescent, there is a range of proliferative ability. The senescent phenotype of ulcer fibroblasts remains intact in vitro as these cells remain viable but are unable to complete DNA synthesis. Fibroblast senescence is not uniform in chronic wounds but varies within areas of the ulcer bed and from patient to patient. Although ulcer fibroblasts exhibit limited proliferative ability, fibroblasts from the ulcer margin and adjacent normal skin show a continued ability to divide. However, in all areas of the wound, the mean generation time of the fibroblast population is longer than commonly observed for cultured human diploid fibroblasts. At first passage, the mean generation time for fibroblasts from all patients is significantly different (p = .001, analysis of variance) among fibroblasts from the ulcer bed (4.2 2.2 days), ulcer margin (2.9 +/- 1.3 days), and adjacent normal skin (1.9 +/- 0.6 days). Analysis of the three cell groups by the post hoc Tukey test, using corrected p values shows that the difference between mean generation times among fibroblast populations from adjacent normal skin and ulcer bed are significantly different (p < 0.05), whereas the difference between fibroblasts from adjacent normal skin and ulcer margin and ulcer margin and ulcer bed are not significantly different (p > 0.05). These data may help to explain the poor response of certain pressure sores to aggressive medical treatment.

Analysis of Variance↗
PubMedDate not supplied

Folding and association of triose phosphate isomerase from rabbit muscle.

The enzymatic activity and quaternary structure of rabbit muscle triose phosphate isomerase remains unchanged in the concentration range from 2 micrograms/ml to 2 ng/ml. In this concentration range the enzyme can be reactivated after dissociation and denaturation in 6.5 M guanidine hydrochloride. Removal of the denaturant by dilution and separation of inactive wrong aggregates (5-20%) lead back to active dimers, indistinguishable from the native enzymes as far as enzymatic and physicochemical properties are concerned. Based on the long term stability of the enzyme, the reactivation kinetics were analyzed at low concentrations and 0 degrees C, conditions where the association of inactive monomers to active dimers is predominant in the process of reactivation. The concentration dependence of the rate of reactivation and the kinetic profiles could be described by a consecutive first-order folding and second-order association reaction scheme with the rate constants kuni = 1.9 X 10(-2)s-1 and kbi = 3 X 10(5) M x s-1. This implies that the folded monomers of triose phosphate isomerase, which are intermediate states during reconstitution, cannot possess appreciable enzymatic activity.

Animals↗
PubMedDate not supplied

Diagnosis of myocardial infarction: integration of serum markers and clinical descriptors using information theory.

OBJECTIVE: We examine the use of information theory applied to a single cardiac troponin T (cTnT) (first generation monoclonal; Boehringer Mannheim Corp., Indianapolis, Indiana) used with the character of chest pain, electrocardiography (ECG) and serial ECG changes in the evaluation of acute myocardial infarction (AMI). We combined a single measure of cTnT (blinded to the investigators) with a creatine kinase MB isoenzyme (CK-MB) measurement to discover the best decision value for this test in a study of 293 consecutive patients presenting to the emergency department with symptoms warranting exclusion of AMI. METHODS: The decision value for determining whether cTnT is positive or negative was determined independently of the final diagnosis by examining the information in the cTnT and CKMB data. Using information theory, an autocorrelation matrix with a one-to-one pairing of the CKMB and troponin T was constructed. The effective information, also known as Kullback entropy, assigned the values for troponin T and for CKMB that have the lowest frequency of misclassification error. The Kullback entropy is determined by subtracting the data entropy from the maximum entropy of the data set in which the information has been destroyed. The assignment of the optimum decision values was made independently of the clinical diagnoses without the construction of a receiver-operator characteristic curve (ROC). The final diagnosis of AMI was independently determined by the clinicians and entered into the medical record. RESULTS: The decision value for cTnT was 0.1 ng/ml as determined by the the information in the data. The method was validated within the same study by mapping the results so obtained into the diagnoses obtained independently by the clinicians using all of the methods at their disposal. The cTnT was different in AMI (n = 60) compared with non-AMI patients (n = 233) (2.08 +/- 0.21 vs. 0.07 +/- 0.10; p < .0001). CONCLUSION: Information theory provides a strong framework and methodology for determining the decision value for cTnT which minimizes misclassification errors at 0.1 ng/ml. The result has a strong correlation with other features in detecting AMI in patients presenting with chest pain.

Creatine Kinase↗
PubMedDate not supplied

Recovery of pituitary-adrenal axis after withdrawal or reduction of systemic corticosteroids in patients with bronchial asthma.

In 36 patients with bronchial asthma a new inhalable corticosteroid (Fluocortin-butyl-ester) was administered to reduce systemic steroids and especially to study the recovery of pituitary-adrenal function. On the basis of the present results, it can be said that patients with the least degree of emphysema and obstruction and with good coughing dynamics and productive expectoration are most suitable for therapy with inhalable corticosteroids. If the systemic steroid reduction is adequate, the recovery phase of the pituitary-adrenocortical system begins after about 5 months and the response to ACTH appraoches normal values after about 8-9 months. About 4 mg prednisolone-equivalent per day can be assumed to be the systemically effective limiting dose. The reducibility as a percentage of the initial dose-regardless of its absolute value- and the maintenance dose achieved also appear to be of equal importance for the recovery of the functional reserve of the pituitary-adrenocortical system. No relationship to the duration of the disease and the initial steroid dose could be demonstrated. The clinical picture of the corticosteroid withdrawal syndrome is dependent on endogenous cortisol synthesis. The symptoms disappear spontaneously with increasing synthesis.

Adrenal Cortex Hormones↗
PubMedDate not supplied

The possible role of bradykinin as a mediator in bronchial asthma.

A variety of antiasthmatic drugs were examined in a bioassay of uterine cornua of rats for determining their influence upon Bradykinin induced contractions. 4 different actions were seen: pronounced, moderate and weak suppression of enhancement of Bradykinin-activity. The most pronounced blocking effect was seen with Fenoterol, Adrenaline and Pheniramine, a moderate effect with Prednisolone and Tolazoline, a weak effect with Propranolol and DSCG. Noradrenaline showed a stimulating effect. It is postulated that Bradykinin acts via alpha-stimulation with concomitant cAMP-decrease after specific binding to Bradykinin-receptors. The results of the study suggest that Bradykinin still must be discussed as a possible mediator in obstructive airway-disease.

Animals↗
PubMedDate not supplied

Reassociation of lactic dehydrogenase from pig heart studied by cross-linking with glutaraldehyde.

Cross-lining with glutaraldehyde has been successfully applied in order to analyze the kinetics of reassociation of oligomeric enzymes (R. Hermann, R. Rudolph, and R. Jaenicke Nature 277, 243 - 245 (1979). In the present study other assembly of lactic dehydrogenase from pig heart is investigated using this approach. In order to eliminate pertubations caused by excessive folding reactions, acid dissociation was performed in the presence o 0.8 M Na2SO4 at 0 degrees C. Under optimum conditions complete cross-linking during reconstitution proves the dimer to be the only intermediate of reassociation. The dimer leads to tetramer transition is found to be rate-limiting for both reassociation and reactivation, suggesting the tetramer to be the enzymatically active species. The presence of monomers during reconstitution indicates that tetramer formation is preceded by a fast monomer-dimer equilibrium. The kinetics model describing the experimental data.

Aldehydes↗