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Biomedical subjects

C Dorn

Publications and source records attributed to C Dorn.

33 records · Page 2Linked to original sources
PubMed2000

Transesophageal versus surface pulse oximetry in intensive care unit patients.

OBJECTIVES: To compare oximetric readings from the esophagus (STEO2) and the skin (finger, SSO2) with those obtained from arterial blood samples (SaO). In addition, to compare the influences of mean arterial pressure (MAP) and body temperature to the accuracy of STEO2 and SSO2 readings. DESIGN: Prospective, single-center study. SETTING: Surgical intensive care unit of an academic, teaching, and community hospital in Austria. PATIENTS: A total of 40 consecutive, severely traumatized or diseased, intensive care unit patients requiring mechanical ventilatory support and deep analgosedation. Patients had to be nonpregnant, > or =19 yrs of age, and without a disease or a trauma of the esophagus. INTERVENTIONS: Placement of an esophageal and a finger-pulse oximetry probe and a radial artery catheter. MEASUREMENTS AND MAIN RESULTS: STEO2, SSO2, MAP, and esophageal temperature were recorded continuously during a 4-hr period, and SaO2 was measured every 30 mins. The first outcome variable was the deviation of STEO2 and SSO2 from SaO2. The second outcome variable was the influence of MAP and body temperature on STEO2 and SSO2 regression analysis and repeated measures. Analysis of variance was used for statistics (p < .05 was accepted as significant). In patients with a MAP ranging from 29 to 111 mm Hg and a temperature ranging from 33.4 degrees C (92.1 degrees to 39.2 degrees C (102.6 degrees F), SSO2 measurements underestimate SaO2 by 2% to 4%. Whereas STEO2 matches SaO2, STEO2 was not dependent on MAP or temperature, but increased temperature or low MAP were associated with falsely low SSO2 readings. CONCLUSIONS: Assuming correct positioning of the probe, readings from the esophagus are more consistent with arterial oxygen saturation than readings from surface pulse oximetry. MAP or temperature changes do not influence STEO2, but they do affect SSO2. In critically ill patients, STEO2 appears to be a more reliable variable than SSO2.

APACHE↗
PubMed2000

Function of steroidogenic factor 1 during development and differentiation of the reproductive system.

Intact reproductive development depends on steroids and other endocrine signals. Although recent discoveries have elucidated important steps of sexual differentiation, the intricate mechanisms that regulate the development of steroid-producing tissues remain elusive. In adults, complex feedback mechanisms determine the hypothalamic and pituitary regulation of steroid hormone biosynthesis. Steroidogenic factor 1 (SF-1), an orphan member of the nuclear receptor superfamily of proteins, plays a critical role in development and differentiation of the endocrine and reproductive systems. This review provides an overview of the function of SF-1, its mechanism of action, and a perspective on the interaction of SF-1 with other determinants of sexual differentiation. Whereas SF-1 is essential for the expression of numerous steroidogenic enzymes, its presence may not correlate with steroidogenic function. Moreover, diverse co-regulators modulate the influence of SF-1 on gene transcription. The significance of these interactions is discussed in the context of reproductive development and function. Other orphan or ligand-dependent nuclear proteins may share similar mechanisms.

Animals↗
PubMed2000

Determination of total interleukin-8 in whole blood after cell lysis.

BACKGROUND: It has been shown that a high percentage of interleukin-8 (IL-8) in blood is cell associated. Recently, a simple method for determination of cell-associated IL-8 in whole blood after cell lysis has been described. The purpose of this study was to evaluate this method, to examine the influence of preanalytic sample handling, and to establish the concentration range of total IL-8 and its relation to age and sex in healthy subjects. METHODS: Total IL-8 content of whole blood was determined after lysing blood cells with Milenia((R)) cell lysis solution. IL-8 in the resulting blood lysate was measured with the IMMULITE((R)) IL-8 immunoassay. RESULTS: When freshly drawn blood was stored up to 48 h on ice, no significant changes in total IL-8 were measured in the subsequently prepared lysate, whereas with storage at room temperature, total IL-8 increased after 3 h from 94 +/- 13 ng/L to 114 +/- 16 ng/L (n = 10). In lysate stored for 48 h at 4 degrees C, marginal changes of the IL-8 concentration were noted, with storage at room temperature, only 76% +/- 5% (n = 12) of initial concentration was recovered. From lysate frozen at -20 and -80 degrees C, respectively, 84% +/- 4% and 93% +/- 2% of initial IL-8 was recovered after 70 days (n = 10). IL-8 was measured with comparable precision in plasma (CV, 3. 2-4.2%) and blood lysate (CV, 3.7-4.1%). When plasma was diluted with cell lysis solution, a slightly overestimated recovery (125% +/- 3%) was observed; for lysate specimens with a cell lysis solution content >/=75%, the recovery after dilution was 98% +/- 2%. In lysate prepared from 12 blood samples with exogenous IL-8 added, IL-8 recovery was 104% +/- 2% (recovery from plasma <35%). The median total IL-8 in blood lysates from 103 healthy subjects (22-61 years) was 83 ng/L of blood (2.5-97.5 percentile range, 49-202 ng/L of blood). In females but not in males, total IL-8 increased significantly with advancing age (P: <0.002). We found grossly increased total IL-8 in six pregnant women with amniotic infection syndrome. CONCLUSIONS: The evaluated method allows the assessment of total IL-8 in blood with good performance when appropriate conditions of sample pretreatment are considered. The values in healthy volunteers all were above the detection limit of the IL-8 assay; therefore, slight changes of total IL-8 could be noted. Thus, the present method is a suitable tool to study the diagnostic relevance of total IL-8 in blood.

Adult↗
PubMed1999

Activation of luteinizing hormone beta gene by gonadotropin-releasing hormone requires the synergy of early growth response-1 and steroidogenic factor-1.

We have previously shown that early growth response (Egr) 1-deficient mice exhibit female infertility, reflecting a luteinizing hormone (LH) beta deficiency. Egr-1 activates the LHbeta gene in vitro through synergy with steroidogenic factor-1 (SF-1), a protein required for gonadotrope function. To test if this synergy is essential for gonadotropin-releasing hormone (GnRH) stimulation of LHbeta, we examined the activity of the LHbeta promoter in the gonadotrope cell line LbetaT2. GnRH markedly stimulated the LHbeta promoter (15-fold). Mutation of either Egr-1 or SF-1 elements within the LHbeta promoter attenuated this stimulation, whereas mutation of both promoter elements abrogated GnRH induction of the LHbeta promoter. Furthermore, GnRH stimulated Egr-1 but not SF-1 expression in LbetaT2 cells. Importantly, overexpression of Egr-1 alone was sufficient to enhance LHbeta expression. Although other Egr proteins are expressed in LbetaT2 cells and are capable of interacting with SF-1, GnRH stimulation of Egr-1 was the most robust. We also found that the nuclear receptor DAX-1, a repressor of SF-1 activity, reduced Egr-1-SF-1 synergy and diminished GnRH stimulation of the LHbeta promoter. We conclude that the synergy between Egr-1 and SF-1 is essential for GnRH stimulation of the LHbeta gene and plays a central role in the dynamic regulation of LHbeta expression.

Animals↗
PubMed1999

Serum oxytocin concentration during embryo transfer procedure.

OBJECTIVE: To determine the effect of the embryo transfer (ET) procedure on serum concentration of oxytocin. STUDY DESIGN: Prospective clinical study of 10 women undergoing in vitro fertilization (IVF) treatment with ET in the Section of Reproductive Medicine and Endocrinology at the Department of Obstetrics and Gynecology, University of Bonn, Germany. Serial blood samples were collected in time intervals of 20 s during embryo transfer procedure and serum oxytocin concentration was measured. RESULTS: In the absence of tenaculum placement, none of the procedures associated with ET led to an increase in serum oxytocin concentration. When tenaculum placement was used, it was temporally (four out of five patients) associated with an elevation in oxytocin level, which remained elevated until of the end of ET procedure. CONCLUSION: Application of a cervical tenaculum during ET or possibly also during intra uterine insemination (IUI) procedure can stimulate the release of oxytocin in some patients.

Adult↗
PubMed1998

Detection of Brucella species in organs of naturally infected cattle by polymerase chain reaction.

A polymerase chain reaction (PCR) assay was used to detect Brucella species in the uterus, udder, spleen, lymph nodes, kidney and liver of three cows which had been naturally infected in an outbreak of brucellosis, and the results were compared with the results of bacteriological investigations. All 18 samples reacted positively in the PCR, but five samples had weak bands after the electrophoretic separation of PCR mixtures. No Brucella strains could be detected in these five samples by bacterial cultivation, but all the other samples gave positive results. A pre-enrichment procedure was necessary for the PCR. A PCR with DNA from eight Yersinia strains gave no amplification product.

Animals↗
PubMed1998

Nuclear receptor DAX-1 recruits nuclear receptor corepressor N-CoR to steroidogenic factor 1.

The orphan nuclear receptor steroidogenic factor 1 (SF-1) is a critical developmental regulator in the urogenital ridge, because mice targeted for disruption of the SF-1 gene lack adrenal glands and gonads. SF-1 was recently shown to interact with DAX-1, another orphan receptor whose tissue distribution overlaps that of SF-1. Naturally occurring loss-of-function mutations of the DAX-1 gene cause the human disorder X-linked adrenal hypoplasia congenita (AHC), which resembles the phenotype of SF-1-deficient mice. Paradoxically, however, DAX-1 represses the transcriptional activity of SF-1, and AHC mutants of DAX-1 lose repression function. To further investigate these findings, we characterized the interaction between SF-1 and DAX-1 and found that their interaction indeed occurs through a repressive domain within the carboxy terminus of SF-1. Furthermore, we demonstrate that DAX-1 recruits the nuclear receptor corepressor N-CoR to SF-1, whereas naturally occurring AHC mutations of DAX-1 permit the SF-1-DAX-1 interaction, but markedly diminish corepressor recruitment. Finally, the interaction between DAX-1 and N-CoR shares similarities with that of the nuclear receptor RevErb and N-CoR, because the related corepressor SMRT was not efficiently recruited by DAX-1. Therefore, DAX-1 can serve as an adapter molecule that recruits nuclear receptor corepressors to DNA-bound nuclear receptors like SF-1, thereby extending the range of corepressor action.

Adrenal Gland Diseases↗
PubMed1997

[Comparison of the results from commercially available Brucella ELISA test kits for the investigation of bovine sera].

Bovine sera from a farm with bacteriologically confirmed brucellosis were taken for comparative serological studies using conventional methods (slow agglutination test--SAT, complement fixation test--CFT, Rose-Bengal-plate-agglutination-test--RBPT) and 5 different commercially available brucellosis ELISA testkits. These serum samples together with other infectious sera producing low level positive antibody titers in conventional tests did not react uniformly when tested by five different commercial ELISA testkits. The introduction of a standard control serum with a general cut-off resulted in a greater uniformity of ELISA results from 4 of 5 ELISA testkits and a closer approach to results of the CFT which is regarded as the confirmatory test for brucellosis. This control serum, on the other hand, was not suitable for the identification of the sensitivity of the various ELISA test kits. For this purpose, in SAT and CFT weakly positive reacting brucella sera from infected farms is needed.

Agglutination Tests↗
PubMed1995

Formation of polymorphonuclear leukocyte elastase: alpha 1 proteinase inhibitor complex and A alpha (1-21) fibrinopeptide in human blood stimulated with the calcium ionophore A23187. A model to characterize inhibitors of polymorphonuclear leukocyte elastase.

Incubation of human blood with the secretagogue A23187 resulted in the formation of increased plasma concentrations of polymorphonuclear leukocyte (PMN) elastase: alpha 1 proteinase inhibitor (PMNE:alpha 1 PI) complex as well as A alpha(1-21) fibrinopeptide [A alpha(1-21)]. The formation of these species was both time and A23187 concentration dependent. Using a sandwich ELISA and a radioimmunoassay, we determined the comparative potencies of several compounds to inhibit the formation of PMNE: alpha 1 PI complexes and A alpha(1-21), respectively. L-658,758, a substituted cephalosporin, essentially irreversible elastase inhibitor, inhibited the formation of PMNE: alpha 1 PI and A alpha(1-21) with IC50 values of 38 and 15 microM, respectively. L-683,845, a monocyclic beta-lactam, was much more potent against isolated PMNE than L-658,758. However in this system it was approximately equivalent to L-658,758 with an IC50 of 15 microM against both species. ICI-200,880, a competitive slow-binding elastase inhibitor, was significantly less potent to inhibit A alpha(1-21), having an IC50 of 75 microM, while Declaben, a reversible noncompetitive inhibitor, was inactive at concentrations as great as 200 microM. We propose that evaluating inhibitors in the complex milieu of blood will provide a useful method to predict their therapeutic potential in vivo.

Calcimycin↗
PubMed1994

Seven-day administration of the gonadotropin-releasing hormone antagonist Cetrorelix in normal cycling women.

In contrast to gonadotropin-releasing hormone (GnRH) agonists, GnRH antagonists do not show any stimulatory effect on the pituitary but their clinical usage was precluded by severe side effects and high dose requirements. We report here on a 7-day treatment using the potent GnRH antagonist Cetrorelix ([Ac-D-Nal(2)1, D-Phe(4Cl)2, D-Pal(3)3, D-Cit6, D-Ala10]GnRH) on five women 23-33 years old. All women were ovulatory and were studied during three consecutive cycles: a control cycle, a treatment cycle and a post-treatment control cycle. Throughout the control cycles blood samples were obtained daily during cycle days 8-18 and on days 21 and 23 during the remainder of the control cycles. On the eighth day of the treatment cycle women were hospitalized at 07.00 h for 26 h. Repeated blood samples were drawn at 15-min intervals during the entire period. Subjects received 3 mg of Cetrorelix sc for the first time at 09.00 h on the eighth day of the cycle and daily at 08.00 h for the following 6 days. Blood samples were obtained daily over a period of 25 days and every third day throughout the remainder of the treatment cycle. Twenty-four hours after the first application of Cetrorelix, luteinizing hormone (LH) and estradiol were in the subnormal range and remained subnormal until the end of medication. The suppressive effect of Cetrorelix compared to pretreatment values lasted at least 6 days for LH and FSH and 11 days after the last Cetrorelix injection for estradiol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1978

Direct fluorescent assay of urokinase and plasminogen activators of normal and malignant cells: kinetics and inhibitor profiles.

A direct rate assay for plasminogen activator has been developed using a synthetic fluorogenic peptide substrate, 7-(N-Cbz-glycylglycylargininamido)-4-methylcoumarin trifluoroacetate. The assay correlates well with the standard 125I-labeled fibrin plate assay using highly purified urokinase, culture fluids from WI-38, Chinese hamster vary or HeLa cells, or Rous sarcoma virus-transformed chick fibroblasts as the source of plasminogen activator. The assay is sensitive, rapid, and linear throughout a wide range of enzyme concentrations. With this substrate it is possible to determine inhibitor profiles for the various plasminogen activators, independently of the interfering potential of plasmin. All of the enzymes tested are inhibited by leupeptin and antipain but not by the related aldehydes, elastatinal and chymostatin. The macromolecular inhibitors soybean trypsin inhibitor and trasylol have little or no effect on the plasminogen activators tested. This substrate should be useful for the study of the effect of various agents on functional changes in cells secreting this enzyme and also should allow kinetic measurements of potential inhibitors.

Animals↗
PubMedDate not supplied

[Increasing number of Salmonella paratyphi B isolates from slaughtered poultry sent in to the national Salmonella reference laboratory].

In the last years the number of isolations of Salmonella enterica subspecies enterica serovar paratyphi B (S. paratyphi B) sent to the national salmonella reference laboratory of Germany has increased steadily. Most of the isolates originated from fowl or poultry products. The bacteriological, serological and biochemical properties of the isolates were investigated. Special emphasis was given to the utilization of d-tartrate which subgroups the serovar. All of them belonged to the d-tartrate positive variant, which is generally considered less virulent for humans and was formerly called S. java. The performance of various tests is compared and in addition the possibility of the spread within the production line is discussed.

Animals↗