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Biomedical subjects

E Jonas

Publications and source records attributed to E Jonas.

27 records · Page 2Linked to original sources
PubMed1981

Influence of growth hormone and thyroxine on thermotropic effects of respiration and 1-anilino-8-naphthalene sulfonate fluorescence and on lipid composition of cardiac membranes.

The effects of hypophysectomy and subsequent administration of growth hormone and/or L-thyroxine on thermotropic properties of State 3 respiration (ADP-induced), cholesterol, phospholipid and fatty acid composition of phospholipid fraction were examined in myocardial mitochondria of rats. Temperature-dependence of 1-anilino-8-naphthalene sulfonate fluorescence was determined in vesicles prepared from lipids of heart mitochondria. Transition temperature obtained from the Arrhenius plots of respiration occurred at 21 and 24 degrees C for heart mitochondria of normal and hypophysectomized rats, respectively. Most notably, after hypophysectomy the rate of respiration was lower below 24 degrees C, but was progressively higher above that temperature when compared to normal rats. The energy of activation was 148 and 36% larger below and above the transition temperature, respectively. Growth hormone restored almost completely the energy of activation and respiratory rates to normal levels. Administration of L-thyroxine, with or without growth hormone, did not significantly change the rate of respiration but decreased the transition temperature to 17.7-17.9 degrees C. Lipid and phospholipid content, as well as percent distribution of phospholipids and their fatty acid composition were not statistically different among the different groups of rats. Only cholesterol content was increased after hypophysectomy. Administration of growth hormone and thyroxine did not significantly change the total unsaturation index of fatty acids, but growth hormone increased the content of arachidonic acid (20 : 4) by 70% but decreased the docosahexaenoic acid (22 : 6) three times which may have a beneficial effect on mitochondrial membranes. These and other results suggest that hormones exert different effects on subcellular organelles in different tissues, like heart and liver.

Anilino Naphthalenesulfonates↗
PubMedDate not supplied

Investigation of neutrophil--endothelial cell interaction in multiple trauma by chemiluminescence.

The trauma-induced activation of neutrophils and their functional alterations, i.e., increase in adherence and release of oxygen derived metabolites, is considered to play a central role in the initiation and amplification of capillary endothelial cell damage and following organ failure. In the present study neutrophil-endothelial cell interaction was studied using an in vitro model of human umbilical cord vein endothelial cells and human neutrophils. Production of oxygen-derived metabolites was determined by comparing mean peak chemiluminescence of neutrophils from multiply traumatized patients (n = 40) and mean peak chemiluminescence of neutrophils from blood donors (n = 160). Adherence and endothelial injury by neutrophils of multiply traumatized patients were compared with data of healthy blood donors. Chemiluminescence response of 70,000 neutrophils isolated from healthy control individuals was 699 +/- 98 x 10(3) cpm and could be increased significantly by endothelial cells to 1410 +/- 135 x 10(3) cpm (p < 0.05). Chemiluminescence response to neutrophils of polytraumatized patients was 1174 +/- 94 x 10(3) cpm and could not be significantly increased by endothelial cells (1419 +/- 120 x 10(3) cpm). Adherence of neutrophils of blood donors to endothelial cells was 12.31 +/- 0.77%. Adherence of neutrophils of polytraumatized patients was significantly increased to values of 24.83 +/- 2.03%. Injury of endothelial cells was not detectable with neutrophils from blood donors (1.11 +/- 1.09% 111in-release). Significantly increased 111in-release was apparent upon incubation with neutrophils of polytraumatized patients (5.76 +/- 1.28%). The data shows evidence of in vivo preactivation of neutrophils of polytraumatized patients, and supports the hypothesis that endothelial cells play an active role in neutrophil-endothelial cell interactions by modulating production of oxygen-derived metabolites.

Abdominal Injuries↗
PubMedDate not supplied

Simultaneous measurement of endothelial cell damage, elastase release and chemiluminescence response during interaction between polymorphonuclear leukocytes and endothelial cells.

Using cultured human umbilical cord vein endothelial cells and human blood neutrophils, the interaction between neutrophils and endothelial cells, in vitro, was studied. The aim of the study was to examine whether a respiratory burst stimulation by neutrophils would be observed by neutrophil/endothelial cell interaction and whether the respiratory burst stimulation of neutrophils by endothelial cells could be enhanced by lipopolysaccharide stimulation of neutrophils. The second aim was whether such an effect, or secretion of elastase, could cause an endothelial cell damage in vitro. Chemiluminescence as an indicator of oxygen-derived metabolites produced by neutrophils, elastase release by neutrophils, and endothelial cell damage, based on 111 In-oxine release from labelled endothelial cells, were measured simultaneously. The present investigation demonstrates that neutrophils can be directly stimulated by endothelial cells. A further amplification of this process following lipopolysaccharide priming up to 10 ng/ml blood could be demonstrated. A slight endothelial cell damage occurs following neutrophil stimulation, although elastase secretion does not increase during interaction between neutrophils and endothelial cells. These results raise the possibility that oxygen-derived metabolites rather than elastase contribute to an endothelial cell damage which might occur in conditions such as endotoxin-induced adult respiratory distress syndrome.

Cell Communication↗
PubMedDate not supplied

In vitro effect of ascorbic acid on neutrophil-endothelial cell interaction.

The effect of different concentrations (0.06, 0.6 and 6.0 mmol/L) of ascorbic acid on neutrophil-endothelial interaction was studied using an in vitro model of human umbilical cord vein endothelial cells and human neutrophils. The aim of the study was to determine changes in chemiluminescence response of neutrophils during adherence to endothelial cells. Because adherence of neutrophils to endothelial cells is an essential component in inflammatory processes leading to endothelial cell injury, the influence of ascorbic acid on adherence and endothelial cell injury have been investigated. Production of oxygen-derived metabolites, measured by chemiluminescence response of neutrophils, decreased significantly in the presence of 6 mmol/L ascorbic acid during coincubation of neutrophils and endothelial cells (p < 0.025). The adherence of neutrophils to endothelial cells was significantly decreased at a concentration of 6 mmol/L (p < 0.0005). The inhibition of neutrophil adherence to endothelial cells was correlated with a diminished neutrophil-mediated endothelial cell injury during incubation with 6 mmol/L ascorbic acid (p < 0.0005). The present results indicate that ascorbic acid might exert a protective effect on neutrophil-mediated endothelial cell injury by decreasing adherence of neutrophils to endothelial cells and by scavenging reactive oxygen metabolites. Moreover, the current investigation points to probable protective effect of ascorbic acid on oxidant-mediated cell damage in diseases (e.g., Adult Respiratory Distress Syndrome).

Ascorbic Acid↗
PubMedDate not supplied

Effect of prostaglandin E1 on chemiluminescence response and adherence of human polymorphonuclear leukocytes to human cultured endothelial cells of prostaglandin E1 treated polytraumatized patients.

We investigated the effect of prostaglandin E1 on human polymorphonuclear leukocytes, in vivo. Polymorphonuclear leukocytes of a prostaglandin E1 and placebo study group were harvested and their function, as production of oxygen-derived metabolites and adherence to human cultured endothelial cells, was compared. Additionally, data obtained from polymorphonuclear leukocytes of a prostaglandin E1 and placebo group were compared with data obtained from polymorphonuclear leukocytes from 28 blood donors, who served as a control group. Production of oxygen-derived metabolites by polymorphonuclear leukocytes during contact with endothelial cells was measured by chemiluminescence. Chemiluminescence was significantly (p < 0.01) increased in the placebo group in comparison to the control group decreasing to values of control group after 6 d (post-trauma). Chemiluminescence response was not significantly suppressed in patients treated with prostaglandin E1 in comparison to the placebo group. Adherence of polymorphonuclear leukocytes (placebo group) to endothelial cells was significantly increased (p < 0.01) within the first 6d post-trauma. Following day 6, values were in the same range as values for the control group. Adherence was not significantly suppressed in patients treated with prostaglandin E1 in comparison to the placebo group. In conclusion, prostaglandin E1 at a dose of 20 ng/kg bw/min does not influence production of oxygen-derived metabolites and adherence in polytraumatized patients in comparison to a placebo group. Additionally, production of oxygen-derived metabolites by polymorphonuclear leukocytes in response to endothelial cells is shown and it is evident that endothelial cells might influence production of oxygen derived metabolites by polymorphonuclear leukocytes.

Alprostadil↗
PubMedDate not supplied

Chemiluminescence response and adherence of neutrophils to cultured endothelial cells--influence of immunoglobulin G.

The effect of different concentrations (0.8, 4.35, 8.7, 17.5, 25 and 35 mg/mL) of intravenous immunoglobulin G (Endobulin) on neutrophil-endothelial cell interaction was studied using an in vitro model of human umbilical cord vein endothelial cells and human neutrophils. Because adherence of neutrophils to endothelial cells is an essential component in inflammatory processes leading to endothelial cell injury the influence of immunoglobulin G on adherence has been investigated. A second aim of the present study was to determine changes in chemiluminescence response of neutrophils during adherence to endothelial cells. Production of oxygen-derived metabolites, measured by chemiluminescence response of neutrophils, decreased significantly in the presence of 8.7 mg immunoglobulin/mL test during coincubation of neutrophils and endothelial cells (p < 0.025). The adherence of neutrophils to endothelial cells was significantly decreased at a concentration of 8.7 mg immunoglobulin/mL test (p < 0.025). The present results indicate that this preparation of immunoglobulin G might exert a protective effect on neutrophil-endothelial cell interaction by decreasing adherence of neutrophils to endothelial cells and by scavenging reactive oxygen metabolites. metabolites. Therefore, the current investigation points to a probable protective effect of immunoglobulin G in oxidative diseases, such as the adult respiratory distress syndrome.

Cell Adhesion↗
PubMedDate not supplied

Acute verapamil toxicity in a patient with chronic toxicity: possible interaction with ceftriaxone and clindamycin.

OBJECTIVE: To report a case of acute toxicity in a patient with chronic verapamil toxicity, possibly precipitated by intravenous administration of the highly protein-bound drugs ceftriaxone and clindamycin. DATA SOURCES: Case reports, review articles, and relevant laboratory and clinical studies identified by MEDLINE (1984-forward), and relevant cross references from those articles. DATA EXTRACTION: Data were abstracted from pertinent sources by one author and reviewed by the remaining authors. CASE SUMMARY: A 59-year-old man who had been receiving sustained-release verapamil 240 mg q12h for more than two years for hypertension, and phenytoin 300 mg/d for many years for prophylaxis against seizures, was noted to be in junctional rhythm when he presented to the emergency room with bilateral pneumonia. Administration of intravenous ceftriaxone 1 g and clindamycin 900 mg precipitated symptoms of acute verapamil toxicity in this patient. The toxicity led to complete heart block requiring cardiopulmonary resuscitation and insertion of a temporary pacemaker. He spontaneously reverted to normal sinus rhythm after 16 hours. Subsequent cardiac evaluation, including echocardiogram, 48-hour dynamic electrocardiographic recording (Holter), and exercise stress test were normal. The patient has remained in sinus rhythm for more than one year after this episode. CONCLUSIONS: We believe that junctional rhythm on admission was a result of chronic verapamil toxicity. This may have been because of increased bioavailability of the drug or increased sensitivity of the receptors. Administration of ceftriaxone, clindamycin, or both agents might have precipitated acute verapamil toxicity by displacing verapamil from its protein-binding sites. Extreme caution is necessary when a highly protein-bound drug is given to a patient already receiving verapamil.

Blood Proteins↗
PubMedDate not supplied

Imaging-based dynamic liver testing--a computerized simulation.

BACKGROUND/AIMS: The mechanisms for maintaining liver function are complex and currently used liver function tests give limited and often nonspecific and insensitive results. The aim of the study was to demonstrate a dynamic liver test with a tomographic imaging modality as sampling method by means of a computer simulation. METHODOLOGY: A virtual three-dimensional liver model, consisting of parenchyma and bile ducts, was created using computer aided design/computer aided manufacturing software. An intravenously administered, bile excreted test substance was simulated in the model by awarding changing densities to the parenchyma and bile ducts in 12 identical sets of the model. RESULTS: Imaging-based density measurements enabled the creation of time-density curves reflecting the transport of the simulated test substance in the parenchymal mass and bile ducts. By means of quantitative analysis of the curves, parenchymal uptake and excretion and intrahepatic bile flow could be assessed independently. CONCLUSIONS: The method enables comparison of function in different liver segments and may have particular value in investigating diseases that affect the liver in a non-homogeneous fashion, for example primary sclerosing cholangitis. Imaging sampling can theoretically be applied with any tomographic imaging technique for which a suitable test substrate exists, including computed tomography, magnetic resonance imaging or single photon emission tomography.

Bile↗