Effects of antioxidants on glutathione levels and clinical recovery from the malnutrition syndrome kwashiorkor – a pilot study

Kwashiorkor is a severe edematous form of malnutrition with high prevalence and lethality in many African countries, and repeatedly has been reported to be associated with oxidative stress. The therapy of kwashiorkor is still ineffective. In this pilot study, we tested the hypothesis that oral application of thiol-containing antioxidants increases glutathione status and is beneficial for the clinical recovery of kwashiorkor patients. The longitudinal clinical intervention study was carried out at St Joseph's Hospital, Jirapa, Ghana. Children with severe kwashiorkor were randomly assigned to either a standard treatment (ST) receiving a therapeutic protocol based on the recommendations of the WHO or to one of three study groups receiving in addition 2 x 600 mg reduced glutathione or 2 x 50 mg alpha-lipoic acid or 2 x 100 mg N-acetylcysteine per day. Patients were followed up clinically and biochemically for 20 days and compared with 37 healthy controls. Both glutathione and alpha-lipoic acid supplementation had positive effects on survival. Also, the blood glutathione concentrations correlated positively with survival rates. Furthermore, the initial skin lesions, glutathione and total protein concentrations were found to be strong predictors of survival. The data strongly suggest that a therapy restoring the antioxidative capacity by applying cysteine equivalents in the form of glutathione and/or alpha-lipoic acid is beneficial for biochemical and clinical recovery of kwashiorkor patients.

Comparison of functional and morphological diagnostics in glaucoma patients and healthy subjects

PURPOSE

To evaluate the diagnostic value of microperimetry (MP), blue-on-yellow perimetry (B/YP), confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph, HRT, III) and optical coherence tomography (OCT) in discriminating eyes with early glaucoma from healthy subjects.

MATERIAL AND METHODS

Prospective examination of 22 eyes of subjects with early primary open-angle glaucoma and 24 eyes of healthy control subjects. After a complete ophthalmological examination, B/YP, MP, OCT and HRT III were determined. Morphological and functional parameters were analysed.

RESULTS

Mean sensitivity threshold values obtained with B/YP and MP did not show significant differences between glaucoma patients and the control group (p = 0.321 and p = 0.281). Retinal nerve fibre layer (RNFL) thickness was significantly decreased in patients with glaucoma with both HRT III and OCT (p = 0.018 and p < 0.001).

CONCLUSIONS

While B/YP and MP had no ability to discriminate between subjects with early glaucoma and healthy subjects, RNFL thickness measured with HRT III and OCT showed a significant difference. In early primary open-angle glaucoma, morphological changes like RNFL thickness seem to occur prior to functional defects in the visual field.

Molecular determinants of the profibrogenic effects of endothelin-1 in pancreatic stellate cells

AIM: To gain molecular insights into the expression and functions of endothelin-1 (ET-1) in pancreatic stellate cells (PSC).

METHODS: PSCs were isolated from rat pancreas tissue, cultured, and stimulated with ET-1 or other extracellular mediators. Cell proliferation was assessed by measuring the incorporation of 5-bromo-2’-deoxyuridine into DNA and cell migration was studied in a transwell chamber assay. Gene expression at the level of mRNA was quantified by real-time polymerase chain reaction. Expression and phosphorylation of proteins were monitored by immunoblotting, applying an infrared imaging technology. ET-1 levels in cell culture supernatants were determined by an enzyme immunometric assay. To study DNA binding of individual transcription factors, electrophoretic mobility shift assays were performed.

RESULTS: Among several mediators tested, transforming growth factor-β1 and tumour necrosis factor-α displayed the strongest stimulatory effects on ET-1 secretion. The cytokines induced binding of Smad3 and NF-κB, respectively, to oligonucleotides derived from the ET-1 promoter, implicating both transcription factors in the induction of ET-1 gene expression. In accordance with previous studies, ET-1 was found to stimulate migration but not proliferation of PSC. Stimulation of ET-1 receptors led to the activation of two distinct mitogen-activated protein kinases, p38 and extracellular signal-regulated kinases (ERK)1/2, as well as the transcription factor activator protein-1. At the mRNA level, enhanced expression of the PSC activation marker, α-smooth muscle actin and two proinflammatory cytokines, interleukin (IL)-1β and IL-6, was observed.

CONCLUSION: This study provides novel lines of evidence for profibrogenic and proinflammatory actions of ET-1 in the pancreas, encouraging further studies with ET-1 inhibitors in chronic pancreatitis.

The clinical value of procalcitonin in the prediction of infected necrosis in acute pancreatitis

OBJECTIVE

Infection of pancreatic necrosis (IN) has a major impact on management and outcome in acute pancreatitis (AP). Currently, guided fine-needle aspiration (FNA) is the only means for an accurate diagnosis of IN. Procalcitonin (PCT), a 116 amino acid pro-peptide of calcitonin has been found in high concentrations in patients with sepsis. In the present study we analyzed the clinical value of serum PCT for predicting IN in AP and compared the results to guided FNA.

DESIGN

Clinical study.

SETTING

A collaborative study between the Departments of General Surgery and Clinical Chemistry/ Pathobiochemistry of the University of Ulm, Germany.

PATIENTS

61 patients with AP entered this study and were stratified into three groups according to morphological and bacteriological data: I. 22 patients with edematous pancreatitis (AIP), II. 18 patients with sterile necrosis (SN), III. 21 patients with IN.

MEASUREMENTS AND RESULTS

During an observation period of 14 days PCT was measured by immunoluminometry, CRP was determined by lasernephelometry on a routine base. In patients with IN overall PCT concentrations were significantly higher than in those with SN, whereas CRP levels did not differ in both groups. In contrast, only low concentrations of both parameters were found in patients with AIP. By ROC analysis the best PCT cut-off level for predicting IN or persisting pancreatic sepsis was obtained at > or =1.8 ng/ml. If this cut-off was reached on at least two consecutive days, IN could be predicted with a sensitivity of 95%, a specificity, of 88%, and an accuracy of 90%. Guided FNA achieved a sensitivity, specificity, and accuracy of 91%. 79%, and 84% in differentiating IN from SN, respectively. After surgical treatment of IN median PCT values continued to be significantly higher in patients with persisting pancreatic sepsis (n=12) compared to those with an uneventful postoperative course (n=7). Our results demonstrate that monitoring of serum PCT could serve as a noninvasive and accurate method to predict IN in AP as well as to select patients with persisting septic complications after surgical debridement.

Characterization of modified low density lipoprotein subfractions by capillary isotachophoresis

Oxidative modification of low density lipoproteins (LDLs) is an important pathogenetic factor in atherosclerosis. The various steps in oxidative modifications of LDL can be monitored using different methodologies with varying degrees of complexity. In this study, we propose capillary isotachophoresis (CITP) as a suitable tool to detect and measure the degree of oxidation of LDL. LDL was isolated from pooled plasma of healthy volunteers by sequential ultracentrifugation, and oxidation was performed in vitro as well as in cell culture experiments. Native LDL and oxidatively modified LDL were characterized by apo B-100 fluorescence and conjugated diene formation. Samples were separated by CITP combined with sudan black B staining. To underline the inherent advantages of this approach, CITP was compared with classical lipoprotein electrophoresis using agarose gel. We demonstrate the CITP method to be highly sensitive, as changes in peak area of the separated LDL subfractions were detected after only 2 h of oxidation. The leading LDL peaks increased, while the terminating LDL peaks decreased in parallel throughout the duration of oxidation. The LDL samples, oxidized for 4-24 h, also exhibited an increased migration velocity of the fractions. In summary, we present the first study investigating LDL-subfractions separated by CITP and the alterations of these LDL-subfractions after gradual in vitro oxidation and after oxidative modification by monocyte-derived macrophages and vascular smooth muscle cells.

2nd Sino-European Congress of Laboratory Medicine--strategies for laboratory diagnostics in medicine

During the 2nd Sino-European Congress in Shanghai in April 2001 the aim of the presentation was an overview on strategies and systems of laboratory diagnostic work. The main focus was to define the prerequisites and the different approaches in the diagnostic work in patients' treatment. In this paper, besides the area of emergency medicine with definition of vital functions and the routine work in deciding between healthy and ill individuals and in the control of therapy, the different aspects in the field of research and teaching are specified. Some aspects of workflow definition and optimization are discussed.

Oxidized low-density lipoproteins bind to the scavenger receptor, CD36, of hepatic stellate cells and stimulate extracellular matrix synthesis

Cumulating evidence suggests that oxidative stress resulting in lipid peroxidation and protein modification is involved in the pathogenesis of chronic liver injury and fibrogenesis. We investigated the effects of oxidized low-density lipoproteins (oxLDL) on collagen and fibronectin synthesis of cultured human and rat hepatic stellate cells (HSC). As shown on protein and mRNA levels, oxLDL dose-dependently stimulated the synthesis of collagen types I and III and fibronectin of cultured HSC. The effect was biphasic, with a maximum between 5 and 25 microg/mL oxLDL (c-fibronectin concentration in HSC supernatants increased 3.9-fold; collagen type I increased 4-fold). Higher oxLDL concentrations were cytotoxic. LDL modified with malondialdehyde (MDA) was not toxic, but stimulated extracellular matrix synthesis as well. As demonstrated by immunofluorescence microscopy (double staining of CD36 and iso-alpha-smooth muscle actin [iso-alpha-sm actin]), immunoblot, and reverse-transcription polymerase chain reaction (RT-PCR), respectively, cultured human HSC express the oxLDL receptor, CD36 (glycoprotein IIIb). Colocalization of CD36 and iso-alpha-sm actin on sinusoidal lining cells was further demonstrated using sections of human fibrotic liver. Preincubation of cultured human HSC with the monoclonal antibody, OKM5, known to block CD36-mediated oxLDL uptake, resulted in a reduction of the oxLDL-stimulated collagen type I synthesis by 56%. In summary, our results demonstrate that low concentrations of modified lipoproteins (oxLDL and MDA-LDL) represent fibrogenic mediators that bind to CD36 and stimulate matrix synthesis of HSC.

Identification of mediators stimulating proliferation and matrix synthesis of rat pancreatic stellate cells

The aim of this study was to identify fibrogenic mediators stimulating activation, proliferation, and/or matrix synthesis of rat pancreatic stellate cells (PSC). PSC were isolated from the pancreas of normal Wistar rats and from rats with cerulein pancreatitis. Cell activation was demonstrated by immunofluorescence microscopy of smooth muscle alpha-actin (SMA) and real-time quantitative RT-PCR of SMA, fibronectin, and transforming growth factor (TGF)-beta(1). Proliferation was measured by bromodeoxyuridine incorporation. Matrix synthesis was demonstrated on the protein and mRNA level. Within a few days in primary culture, PSC changed their phenotype from fat-storing to SMA-positive myofibroblast-like cells expressing platelet-derived growth factor (PDGF) alpha- and PDGF beta-receptors. TGF-beta(1) and tumor necrosis factor (TNF)-alpha accelerated the change in the cells' phenotype. Addition of 50 ng/ml PDGF and 5 ng/ml basic fibroblast growth factor (bFGF) to cultured PSC significantly stimulated cell proliferation (4.37 +/- 0.49- and 2.96 +/- 0.39-fold of control). Fibronectin synthesis calculated on the basis of DNA was stimulated by 5 ng/ml bFGF (3.44 +/- 1.13-fold), 5 ng/ml TGF-beta(1) (2.46 +/- 0.89-fold), 20 ng/ml PDGF (2.27 +/- 0.68-fold), and 50 ng/ml TGF-alpha (1.87 +/- 0.19-fold). As shown by RT-PCR, PSC express predominantly the splice variant EIII-A of fibronectin. Immunofluorescence microscopy and Northern blot confirmed that in particular bFGF and TGF-beta(1) stimulated the synthesis of fibronectin and collagens type I and III. In conclusion, our data demonstrate that 1) TGF-beta(1) and TNF-alpha accelerate the change in the cell phenotype, 2) PDGF represents the most effective mitogen, and 3) bFGF, TGF-beta(1), PDGF, and, to a lesser extent, TGF-alpha stimulate extracellular matrix synthesis of cultured rat PSC.

Serum amyloid A versus C-reactive protein in acute pancreatitis: clinical value of an alternative acute-phase reactant

OBJECTIVES

The acute-phase reactant C-reactive protein (CRP) is currently the serum variable of choice for an early, accurate, and cost-effective severity assessment of acute pancreatitis in the daily clinical routine. Serum amyloid A (SAA) proteins comprise a family of apolipoproteins that constitute another major acute-phase reactant and thus could be a potential alternative to CRP assessment. In the present study we investigated the clinical usefulness of SAA determinations in acute pancreatitis using an automated immunoassay technique.

DESIGN

Cohort study, comparing patients with complicated and mild acute pancreatitis; control groups included individuals with further abdominal disorders and healthy volunteers.

SETTING

A collaborative study between the department of general surgery and the routine laboratory of the department of clinical chemistry/pathobiochemistry.

PATIENTS

We enrolled 66 patients with acute pancreatitis in the present study. Control groups consisted of healthy subjects (n = 30), patients with chronic pancreatitis (n = 20), patients with pancreatic carcinoma (n = 20), and patients with acute appendicitis (n = 20).

INTERVENTIONS

Blood samples were collected during 14 consecutive days in patients with acute pancreatitis. A single blood specimen was taken in all control groups after the diagnosis was established.

MEASUREMENTS AND MAIN RESULTS

SAA concentrations were 3 mg/L (median; range, 3-93) in healthy subjects. Although SAA and CRP both reached their maximum within 4 days after onset of symptoms in patients with acute pancreatitis, SAA concentrations rose faster above normal ranges and reached 676 mg/L (median; range, 12-1880), higher than CRP, which reached 313 mg/L (median; range, 29-613). As observed for CRP, SAA was significantly higher in patients who developed complications such as necrosis, infection of necrosis, or multiple organ dysfunction syndrome or in patients who died. SAA achieved best results in discriminating between necrotizing pancreatitis and interstitial edematous pancreatitis. However, CRP provided an earlier differentiation between both entities and a significantly better overall accuracy, as shown by receiver operating characteristics analysis. SAA concentrations in patients with chronic pancreatitis were 6 mg/L (median; range, 3-756). In patients with pancreatic carcinoma, SAA concentrations were 7 mg/L (median; range, 3-492), and in patients with acute appendicitis, they were 50 mg/L (median; range, 3-2140).

CONCLUSION

SAA is a nonspecific and rapidly produced variable in inflammatory abdominal disorders with a wider dynamic range than CRP. The current assay technique renders SAA an applicable and readily available variable under clinical routine conditions. In cases of acute pancreatitis, however, CRP is still superior to SAA for early and accurate stratification of patients with a complicated course.

Platelet-derived growth factors stimulate proliferation and extracellular matrix synthesis of pancreatic stellate cells: implications in pathogenesis of pancreas fibrosis

At present, the cell-cell interactions and molecular mechanisms of pancreas fibrogenesis are largely unknown. The purpose of this study was to investigate paracrine stimulatory loops between platelets and pancreatic stellate cells (PSC). Human PSC were obtained by outgrowth from fibrotic human pancreas. Native platelet lysate (nPL) and transiently acidified platelet lysate (aPL) were added to cultured PSC (passage 4 to 7) in the absence of serum. The synthesis of collagen types I and III and c-fibronectin (cFN) was demonstrated on protein (immunofluorescence and quantitative immunoassay) and mRNA (Northern blot) level. Using sections of human pancreas with acute pancreatitis, platelet aggregates in capillaries were demonstrated by transmission electron microscopy. nPL, and to an even greater extent aPL, significantly increased the synthesis of collagen types I and III and of c-FN (120 microl/ml aPL increased collagen type I concentration in PSC supernatants by 1.99 +/- 0.17 times and c-FN of 2.49 +/- 0.28 times, mean +/- SD, n = 3). nPL and aPL also significantly stimulated cell proliferation (increased bromodeoxyuridine (BrdU) incorporation by 6.4 +/- 0.78 times and 10 +/- 0.29 times, respectively). By preincubating aPL with transforming growth factor beta (TGFbeta)- and platelet-derived growth factor (PDGF)-neutralizing antibodies and the TGFbeta-latency associated peptide, respectively, TGFbeta1 was identified as the main mediator stimulating matrix synthesis and PDGF as the responsible mitogen. Our data demonstrate that platelets contain fibrogenic mediators that stimulate proliferation (PDGF) and matrix synthesis (TGFbeta1) of cultured PSC. We suggest that platelets and PSC cooperate in the development of pancreas fibrosis.

Lipopolysaccharide-activated macrophages stimulate the synthesis of collagen type I and C-fibronectin in cultured pancreatic stellate cells

We have recently identified and characterized pancreatic stellate cells (PSC) in rats and humans (Gastroenterology 1998, 15:421-435). PSC are suggested to represent the main cellular source of extracellular matrix in chronic pancreatitis. Now we describe a paracrine stimulatory loop between human macrophages and PSC (rat and human) that results in an increased extracellular matrix synthesis. Native and transiently acidified supernatants of cultured macrophages were added to cultured PSC in the presence of 0.1% fetal calf serum. Native supernatants of lipopolysaccharide-activated macrophages stimulated the synthesis of collagen type I 1.38 +/- 0.09-fold of control and c-fibronectin 1.89 +/- 0.18-fold of control. Transiently acidified supernatants stimulated collagen type I and c-fibronectin 2.10 +/- 0.2-fold and 2.80 +/- 0.05-fold of control, respectively. Northern blot demonstrated an increased expression of the collagen-I-(alpha-1)-mRNA and fibronectin-mRNA in PSC 10 hours after addition of the acidified macrophage supernatants. Cell proliferation measured by bromodeoxyuridine incorporation was not influenced by the macrophage supernatants. Unstimulated macrophages released 1.97 pg TGFbeta1/microgram of DNA over 24 hours and lipopolysaccharide-activated macrophages released 6.61pg TGFbeta1/microgram of DNA over 24 hours. These data together with the results that, in particular, transiently acidified macrophage supernatants increased matrix synthesis, identify TGFbeta as the responsible mediator. In conclusion, our data demonstrate a paracrine stimulation of matrix synthesis of pancreatic stellate cells via TGFbeta1 released by activated macrophages. We suggest that macrophages might play a pivotal role in the development of pancreas fibrosis.

Separation of lipoproteins by capillary isotachophoresis combined with enzymatic derivatization of cholesterol and triglycerides

Combining specific enzymatic derivatization of cholesterol or triglycerides with capillary isotachophoresis (CITP), human serum lipoproteins are separated into 14 lipoprotein subfractions, monitored and quantitated by direct capillary UV detection. By comparing the separation patterns of human serum with the patterns of lipoprotein particles isolated by sequential ultracentrifugation it became evident that peaks 1-5 represent lipoproteins of the high density lipoprotein (HDL) fraction, peaks 6-8 embody the very low density lipoprotein (VLDL) fraction and chylomicrons, and peaks 7-14 represent the low density lipoprotein (LDL) fraction. Peaks 7 and 8 were found in the VLDL as well as in the LDL fraction. Using triglyceride-specific staining peaks 6-8 occurred prominently; and with cholesterol-specific staining, peaks 1-5 and 7-14 were prominent. The coefficient of variation, for the sum of the peak heights of a pooled serum, was 3.94 for triglyceride-specific staining and 2.32 for cholesterol-specific staining. A linearity range between 0.23 and 2.29 mM/L was found for triglyceride-specific staining and between 0.043 and 4.33 mM/L for cholesterol-specific staining. The practicability of the method was evaluated (i) using blood of humans before and 45 min after an oral fat load. Triglyceride-specific staining revealed a prominent increase in the VLDL fraction and chylomicrones containing peaks 6 and 7, and a minor increase in the HDL fraction containing peaks 3 and 4, and (ii) in patients with manifest hypothyroidism before and after thyroxine therapy. Cholesterol-specific staining demonstrated a massive decrease in the first peak of the HDL fraction and in peaks 9 and 11 of the LDL fraction regarding the hypo versus hyperthyroid state.

Zinc status in patients with alveolar echinococcosis is related to disease progression

Zinc is an essential trace element for immune function that plays a role in immune response against parasites. To determine a possible relationship between zinc level and disease status in alveolar echinococcosis (AE), we investigated serum concentrations of zinc, immunoglobulin (Ig)E, IgG, and C-reactive protein (CRP) in 40 AE patients and 20 controls. Patients were classified into three groups: group A: patients after curative surgery, group B: patients with stabilized disease, group C: patients with progressive disease. Patients showed significantly higher levels of IgE and IgG than controls. Amounts of IgE and IgG were related to disease severity, achieving highest levels in group C and lowest in group A. Zinc levels were comparable in patients and controls. However, there was an obvious association between zinc concentration and disease severity. Zinc was far below the normal range in group C (median 9.2 micromol/l) and significantly diminished compared to group B and controls. An inverse pattern was seen for CRP. In conclusion, lowered zinc concentration in progressive cases may be caused by enhanced immune activation but consumption of zinc by the growing parasite may also play a role. Furthermore, decreased zinc levels may contribute to the observed immunosuppression in AE.

Serum half-life time determination of free and total prostate-specific antigen following radical prostatectomy--a critical assessment

OBJECTIVES

All studies investigating the elimination kinetics of serum total (tPSA) and free (fPSA) prostate-specific antigen (PSA) were carried out in men undergoing radical prostatectomy. Radical prostatectomy itself could, however, have a major influence on the serum concentration of these tumor markers (e.g., perioperative fluid shift or blood loss). The purpose of our study was to determine the half-life time of fPSA and tPSA with special regard to the influence of the radical prostatectomy on the serum concentration of these tumor markers.

METHODS

Eleven men (mean age 63.2+/-7.2 years) with organ-confined prostate cancer who underwent radical prostatectomy were investigated (final pathologic Stage pT2pN0 or lower). Serum samples were obtained preoperatively and 0.25, 0.5, 1, 2, 4, 8, 12, 16, 24, 48, 72, 120, 168, and 240 hours after removal of the prostate. fPSA and tPSA and albumin and total protein serum concentrations were determined in all samples.

RESULTS

During the first 120 minutes after removal of the prostate, albumin and total protein serum concentrations continuously declined, with a half-life time of -104.5+/-28 minutes and -129.7+/-32 minutes, respectively. Serum decline of fPSA and tPSA followed a biphasic kinetic. During the initial alpha-phase, fPSA and tPSA serum concentrations decreased, with a half-life time of -69+/-10.3 minutes and -87.3+/-18.1 minutes, respectively. During the terminal beta-phase, the half-life time of fPSA and tPSA was -1152.2 minutes (0.8 days) and -3916.1 minutes (2.7 days), respectively. Between the alpha-phase half-life time of fPSA or tPSA and the half-life time of the total protein or albumin concentration decline, significant correlations were found.

CONCLUSIONS

These correlations indicate that the rapid decline of fPSA and tPSA directly after removal of the prostate (alpha-phase half-life time) is caused by the radical prostatectomy itself. The half-life time of the beta-phase reflects the biologic clearance of PSA. Therefore, the half-life time determination of PSA after radical prostatectomy is of limited value if the influence of the operation itself on the serum PSA concentration is not taken into account.

Depending on their concentration oxidized low density lipoproteins stimulate extracellular matrix synthesis or induce apoptosis in human coronary artery smooth muscle cells

Various lines of evidence indicate that oxidative stress resulting in lipid peroxidation and protein modification is involved in the pathogenesis of atherosclerosis and coronary heart disease. We have investigated the effect of modified (oxidized) low-density lipoproteins (oxLDL) on collagen and fibronectin synthesis in cultured human coronary artery smooth muscle cells (HCA-SMC). As shown by immunofluorescence microscopy and time-resolved fluorescence immunoassay, oxLDL dose-dependently stimulated collagen type I and fibronectin synthesis in cultured HCA-SMC. The effect on matrix synthesis was biphasic, with a maximum effect at concentrations between 1 and 10 microg/ml oxLDL. Higher oxLDL concentrations (>25 microg/ml) were cytotoxic. Beside oxLDL, malondialdehyde-modified LDL also stimulated extracellular matrix synthesis. In the presence of 100 microg/ml ascorbic acid, 25, 50 and 100 microg/ml oxLDL induced apoptosis within 6-8 hours (demonstrated by TUNEL-reaction, annexin-V binding and APO-2.7-expression). Apoptosis was not induced by normal (unmodified) LDL and malondialdehyde-modified LDL. The radical scavengers and antioxidants TROLOX and probucol and the hydrogen peroxide eliminator catalase significantly reduced oxLDL-induced apoptosis. Our results demonstrate that low concentrations of oxLDL are profibrogenic by stimulating extracellular matrix synthesis, whereas higher oxLDL concentrations induce oxidative stress and apoptosis in coronary artery smooth muscle cells. The profibrogenic effect might be relevant in the formation of atherosclerotic plaques, and the proapoptotic effect might contribute to an increased plaque vulnerability.

Prognostic significance of soluble interleukin-2 receptor-alpha in adenocarcinoma of the pancreas

Soluble interleukin-2-receptor-alpha (sIL-2Ralpha) serum concentrations were examined in chronic pancreatitis patients, patients with cystadenocarcinoma of the pancreas, patients with adenocarcinoma of the pancreas and healthy blood donors. sIL-2Ralpha serum concentrations in pancreatic cancer patients were significantly higher than those of normal control subjects or chronic pancreatitis patients. In patients with adenocarcinoma of the pancreas no significant differences were found between sIL-2Ralpha and tumor size, grading, resectability and lymph node involvement. In Kaplan-Meier regression analysis patients with adenocarcinoma of the pancreas with low sIL-2Ralpha levels (<500 U/ml) lived significantly shorter than patients with sIL-2Ralpha concentrations above 500 U/ml (P < 0.01), suggesting that determination of sIL-2Ralpha serum concentrations could provide additional important information about prognosis.

Identification, culture, and characterization of pancreatic stellate cells in rats and humans

BACKGROUND & AIMS

Until now, the basic matrix-producing cell type responsible for pancreas fibrosis has not been identified. In this report, retinoid-containing pancreatic stellate cells (PSCs) in rat and human pancreas are described, and morphological and biochemical similarities to hepatic stellate cells are shown.

METHODS

Electron and immunofluorescence microscopy (collagen types I and III, fibronectin, laminin, alpha-actin, and desmin) was performed using pancreatic tissue and cultured PSCs. Extracellular matrix synthesis was shown using quantitative immunoassay and Northern blot analysis.

RESULTS

PSCs are located in interlobular areas and in interacinar regions. Early primary cultured PSCs contain retinol and fatty acid retinyl-esters. Addition of retinol to passaged cells resulted in retinol uptake and esterification. During primary culture, the cells changed from a quiescent fat-storing phenotype to a highly synthetic myofibroblast-like cell expressing iso-alpha-smooth muscle actin (>90%) and desmin (20%-40%) and showing strong positive staining with antibodies to collagen types I and III, fibronectin, and laminin. As determined on protein and messenger RNA level, serum growth factors stimulated the synthesis of collagen type I and fibronectin.

CONCLUSIONS

The identification of PSCs, particularly in fibrotic areas, and the similarities of these cells to hepatic stellate cells suggest that PSCs participate in the development of pancreas fibrosis.

The potential role of procalcitonin and interleukin 8 in the prediction of infected necrosis in acute pancreatitis

BACKGROUND

Infection of pancreatic necrosis has a major impact on clinical course, management, and outcome in acute pancreatitis. Currently, guided fine needle aspiration is the only means for an early and accurate diagnosis of infected necrosis. Procalcitonin (PCT), a 116 amino acid propeptide of calcitonin, and interleukin 8 (IL-8), a strong neutrophil activating cytokine, are markers of severe inflammation and sepsis.

AIMS

To analyse the clinical value of PCT and IL-8 as biochemical parameters for predicting infected necrosis in acute pancreatitis.

PATIENTS AND METHODS

Fifty patients with acute pancreatitis entered this prospective study and were stratified into three groups according to morphological and bacteriological findings: 18 patients with oedematous pancreatitis (group I), 14 patients with sterile necrosis (group II), and 18 patients who developed infected necrosis a median of 13.5 days after the onset of symptoms (group III). After admission serum samples were drawn daily for two weeks. Concentrations of PCT and IL-8 were measured by chemoluminescent immunoassays (upper reference range 0.5 ng/ml for PCT and 70 pg/ml for IL-8). The routine parameter C-reactive protein was determined by laser nephelometry (upper reference range 10 mg/l).

RESULTS

Median concentrations of PCT and IL-8 were significantly higher in patients with infected necrosis than in those with sterile necrosis during the observation period, whereas there was no difference in C-reactive protein. In oedematous pancreatitis overall median concentrations of all three parameters were low. By receiver operating characteristics best cut off levels for predicting infected necrosis or persisting pancreatic sepsis were 1.8 ng/ml for PCT and 112 pg/ml for IL-8. If these cut off levels were reached on at least two days, sensitivity, specificity, and accuracy for the prediction of infected necrosis were 94%, 91%, and 92% for PCT and 72%, 75%, and 74% for IL-8, respectively. After surgical treatment of infected necrosis median PCT and IL-8 values continued to be significantly higher in patients with persisting pancreatic sepsis (n = 11) compared with those having an uneventful postoperative course (n = 7). For the preoperative differentiation between infected necrosis and sterile necrosis guided fine needle aspiration was performed in 24 patients with necrotising pancreatitis and reached a diagnostic accuracy of 84% compared with 87% for PCT, and 68% for IL-8. There was no correlation between the aetiology of acute pancreatitis or the extent of necrosis and PCT or IL-8.

CONCLUSION

PCT and IL-8 are found in high concentrations in infected necrosis and associated systemic complications in patients with acute pancreatitis. The course of PCT shows the closest correlation with the presence of infected necrosis. Monitoring of serum PCT is a potential new marker for the non-invasive and accurate prediction of infected necrosis as well as for the selection of patients with persisting septic complications after surgical debridement.

Alteration of n-3 fatty acid composition in lung tissue after short-term infusion of fish oil emulsion attenuates inflammatory vascular reaction

OBJECTIVES

To investigate whether modulation of the fatty acid profile can be achieved by the short-term infusion of a fish oil emulsion which may attenuate the pulmonary response to inflammatory stimulation. Changes of fatty acid pattern in-lung tissue and perfusate were analyzed and correlated with physiologic data after a 3-hr infusion of fish oil in comparison with a soybean oil preparation.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Experimental laboratory in a university teaching hospital.

SUBJECTS

Forty standard breed rabbits of either gender.

INTERVENTIONS

Isolated lungs from anesthetized rabbits were ventilated and recirculation-perfused (200 mL/min) with 200 mL of cell-free buffer solution to which either 2 mL of saline (control, n = 6), 2 mL of a 10% soybean oil preparation (n = 6), or 2 mL of a 10% fish oil emulsion (n = 6) were added. Samples of perfusate and lung tissue were collected for analysis of fatty acid composition. Tissue and perfusate fatty acid composition were analyzed by capillary gas chromatography. To study metabolic alterations in states of inflammatory stimulation, lungs of each group were stimulated with small doses of the calcium ionophore, A23187 (10(-8) M), during the 180-min lipid perfusion period and again after washing out the lipids by exchanging the perfusion fluid. Pulmonary arterial pressure and lung weight gain were monitored, and eicosanoids were analyzed in the perfusate.

MEASUREMENTS AND MAIN RESULTS

Free eicosapentaenoic acids increased several-fold in lung tissue and perfusate during a 3-hr infusion with fish oil. The intravenously administered n-3 fatty acids were rapidly hydrolyzed, as indicated by the appearance of substantial quantities of eicosapentaenoic acid in the perfusate free fatty acid fraction. This increase of perfusion levels of eicosapentaenoic acid was paralleled by an attenuated pressure increase and edema formation due to calcium ionophore challenge and an altered eicosanoid spectrum determined in the perfusate compared with soybean oil-treated lungs.

CONCLUSION

Short-term n-3 lipid application (fish oil emulsion) exerts anti-inflammatory effects on lung vasculature, which may be due to the metabolism of eicosapentaenoic acid resulting in the generation of less potent inflammatory eicosanoids.

Increased endothelin release by cultured human smooth muscle cells from atherosclerotic coronary arteries

OBJECTIVES

Endothelin, a 21-amino acid peptide initially purified from the medium of cultured endothelial cells, is a potent vasoconstrictor exerting its effects predominantly in a paracrine or autocrine manner. Recent data indicate that endothelin is also synthesized by cultured vascular smooth muscle cells and that endothelin is an effective stimulator of smooth muscle cell proliferation. This study aimed to investigate the endothelin release of cultured human smooth muscle cells, isolated from coronary plaques and from normal coronary tunica media, and to determine circulating endothelin concentrations in patients with coronary artery disease compared to control subjects.

METHODS

Coronary plaque material was extracted by thrombendarterectomy during aorto-coronary bypass grafting (n = 19). Segments of normal coronary arteries were obtained at autopsy (n = 33). Cells were isolated by enzymatic disaggregation and identified as smooth muscle cells with antibodies against smooth muscle alpha-actin. Venous blood samples were drawn from patients with coronary artery disease undergoing cardiac catheterization (n = 32) and from control subjects (n = 38). Endothelin concentrations in culture medium and in plasma samples were measured by radioimmunoassay after Sep Pak C18 extraction.

RESULTS

Cultured smooth muscle cells, isolated from coronary plaques, released a significantly (P < 0.001) higher amount of immunoreactive endothelin into the culture medium (39.2 +/- 3.9 pg/10(4) cells, mean +/- s.e.m., 31 supernatant samples) than smooth muscle cells from normal coronary tunica media (3.9 +/- 0.8 pg/10(4) cells, 28 samples). Circulating endothelin concentrations were slightly elevated (P < 0.01) in patients with coronary artery disease (3.8 +/- 0.2 pg/ml) compared to control subjects (3.0 +/- 0.2 pg/ml).

CONCLUSIONS

These data suggest that the endothelin production is markedly increased in smooth muscle cells of coronary atherosclerotic plaques. The enhanced endothelin release may stimulate smooth muscle cell proliferation in a paracrine or autocrine manner and thus may contribute to the development or progression of coronary artery disease.

Water turnover and body composition during long-term exposure to high altitude (4,900-7,600 m)

Thirteen healthy subjects (11 men and 2 women; 30.2 +/- 5.4 yr; 73.5 +/- 10.3 kg; 178.9 +/- 10.4 cm; body mass index, 22.9 +/- 1.6 kg/m2) participated at the 62-day expedition to the Broad Peak (8,047 m), Pakistan. Weight, body water, and water turnover (deuterium dilution and elimination) were measured eight times to assess long-term changes. Body weight fell during the ascent to the base camp [from 73.2 +/- 9.8 (baseline) to 71.7 +/- 9.7 kg; P < 0.05] and decreased until the end of the base camp stay (66.7 +/- 7.2 kg; P < 0.0001). Body compartments changed at different rates. Total body water decreased during the ascent (from 43.1 +/- 7.3 to 41.0 +/- 7.7 liters; P < 0.05) and remained unchanged until the base camp was reached (41.2 +/- 6.9 liters; P < 0.01) but decreased further during the base camp stay (40.6 +/- 5.2 liters). Water content of the body (total body water-to-body weight ratio) fell during the ascent (from 58.6 +/- 3.4 to 55.8 +/- 4.4%; P < 0.01), approached the baseline value during the base camp (57.4 +/- 4.0 and 58.3 +/- 5.1%), and increased again until the end of the base camp (60.6 +/- 3.4 and 60.9 +/- 4.3%). The compartment of the solids increased during the ascent (from 30.2 +/- 3.4 to 32.2 +/- 4.9 kg; P < 0.01) and approached the baseline value on arrival at the base camp (30.5 +/- 4.7 kg). Until the end of the base camp, the compartment of the solids fell (26.9 +/- 2.6 and 26.1 +/- 4.0 kg), indicating that weight loss was due to a loss of body solids, presumably mostly fat mass. Water turnover during the pretest period (sea level) was 45 +/- 7 ml.kg-1.day-1; it increased during the ascent (56 +/- 11 and 60 +/- 10 ml.kg-1.day-1) but remained constant during the base camp stay (63 +/- 12, 58 +/- 9, and 56 +/- 10 ml.kg-1.day-1). It increased during the ascent to Broad Peak (73 +/- 20 ml.kg-1.day-1; P < 0.05) and even more during the descent to civilization (83 +/- 17 ml.kg-1.day-1; P < 0.05).

Elevated plasma endothelin concentrations in cyclosporine-treated patients after bone marrow transplantation

Administration of cyclosporine is often associated with the development of renal dysfunction and hypertension. Since recent data from animal experiments provide evidence that endothelin, a potent vasoconstrictive peptide, might play a role in mediating cyclosporine-related renal and cardiovascular side-effects, the present study was designed to investigate whether plasma endothelin concentrations are elevated in cyclosporine-treated patients. Plasma endothelin concentrations, determined by radioimmunoassay after Sep Pak C18 extraction, were significantly elevated in cyclosporine-treated patients after bone marrow transplantation (8.3 +/- 1.4 ng/l, n = 28) compared to patients not treated with cyclosporine after bone marrow transplantation (3.9 +/- 0.2* ng/l, n - 11), patients with haematological disorders (3.9 +/- 0.3** ng/l, n = 11) not treated with bone marrow transplantation and to normal control subjects (3.1 +/- 0.2*** ng/l, n = 33) (*P < 0.05, **P < 0.01, ***P < 0.001). Furthermore, plasma endothelin levels exhibited a significant correlation with cyclosporine concentrations (r = 0.57, P < 0.01). The present data, demonstrating elevated plasma endothelin concentrations in cyclosporine-treated patients, suggest that the cyclosporine-associated renal and cardiovascular side-effects might in part be mediated by cyclosporine-induced stimulation of endothelin release.

Unchanged 5'-deiodinating activity during the induction of a nonthyroidal illness

We investigated the formation of a "nonthyroidal illness" (NTI) in pigs undergoing ventricular fibrillation (VF) and resuscitation. Seven minutes after VF twenty-one pigs received either Epinephrine (E: 45 micrograms/kg B.W.; n = 7), Norepinephrine (NE: 45 micrograms/kg B.W.; n = 7), or Vasopressin (VP: 0.8 U/kg B.W.; n = 7). We determined the serum concentrations (sc) of total T4 (TT4), FT4, total T3 (TT3) and rT3 120 min before, during (t0), and 5, 15, 60 and 120 min after VF. At the end of the observation period we figured out the in-vitro T3-generation (kM, Vmax), the in-vitro rT3-generation, the in-vitro rT3-decomposition (kM, Vmax) and the content of cytosolic sulfhydryls (total sulfhydryls, non-protein bound sulfhydryls) in liver and kidney specimen. Animals not undergoing VF served as controls (C) for parameters measured in the intracellular compartment. TT4- and TT3-sc decreased to 3.3 +/- 0.6 micrograms/dl (p < 0.05, vs. t0) and 15.2 +/- 4.1 ng/dl (p < 0.05, vs t0), resp. FT4-sc remained stable for five minutes (2.63 +/- 0.41 ng/dl) before declining to 1.8 +/- 0.39 ng/dl (p < 0.05, vs. t0). The rT3-sc raised finally to 46.9 +/- 7.3 ng/dl (p < 0.05, vs t0). Iodothyronine sc did not exhibit differences between E-, NE- and VP-treatment. Neither in-vitro T3-generation, nor in-vitro rT3-generation, nor in-vitro rT3-decomposition nor intracellular sulfhydryl content were affected by the events of VF and resuscitation as compared to the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Are the effects of noradrenaline, adrenaline and dopamine infusions on VO2 and metabolism transient?

OBJECTIVE

To determine whether noradrenaline, adrenaline and dopamine have persistent actions on VO2 and metabolism.

DESIGN

Descriptive laboratory investigation.

SETTING

Laboratory of the Department of Anaesthesiology at a University Hospital.

SUBJECTS

9 volunteers.

INTERVENTION

VO2 and the plasma concentration of glucose and free fatty acids were measured prior to and during a 4 h infusion of saline (control), noradrenaline (0.14 microgram/kg min) adrenaline (0.08 microgram/kg min) or dopamine (7 micrograms/kg min), n = 9 each. VO2 was measured using an open circuit gas exchange system.

MEASUREMENTS AND MAIN RESULTS

VO2 increased from 250 +/- 22 ml/min to 280 +/- 38 ml/min during noradrenaline, to 298 +/- 30 ml/min during adrenaline and to 292 +/- 39 ml/min during dopamine infusion. The plasma glucose concentration increased from 6.2 +/- 0.6 mmol/l to 8.8 +/- 0.8 mmol/l, 13.2 +/- 1.4 and 7.3 +/- 0.4 mmol/l during infusion of noradrenaline, adrenaline or dopamine, respectively. The plasma free fatty acid concentration increased from 0.28 +/- 0.10 mmol/l to 0.79 +/- 0.21 mmol/l during noradrenaline and to 0.52 +/- 0.09 mmol/l during dopamine. In contrast, free fatty acid values averaged baseline values at the end of the adrenaline infusion after an initial increase to 0.72 +/- 0.31 mmol/l.

CONCLUSIONS

Administration of noradrenaline, adrenaline or dopamine resulted in persistent increases in VO2 in volunteers. With the exception of the transient adrenaline effect on fatty acids the metabolic actions were steady during 4 h of adrenergic stimulation. Since the adrenergic effect on VO2 is persistent over time a similar action in patients (e.g. septic shock) during treatment with adrenoceptor agonists may be important. Thus, an increase in VO2 during therapy may not only reflect an oxygen debt but also a pharmacodynamic action of adrenoceptor mediated calorigenic and metabolic induction.

[Artificial oxygen carriers--perfluorocarbons]

The paper summarizes chemical, physical and physiological qualities of modern perfluorinated carbons. The indications for the application of these artificial oxygentransporting substances in the biological and medical field are summarized and discussed. The characteristics of perfluorocarbons are looked at from historical and current points of view in order to indicate the fields of application and especially the limitations of their applicability. Without any doubt application as a full replacement of blood will be impossible because blood with its multifunctional property cannot be replaced by systems which cover only one or few aspects. Besides this general statement it is also clear that the special qualities of perfluorocarbons make them highly suitable for application in biological and medical fields; their low viscosity allows to improve disturbancies in perfusion. Immunological problems do not occur, and the danger of infection is eliminated compared to biological material. The most important fields of application for perfluorocarbons are the organ perfusion in organ banks for transplantation, the oxygenation of cell cultures and the diagnosis with imaging procedures.

Increased brain natriuretic peptide and atrial natriuretic peptide plasma concentrations in dialysis-dependent chronic renal failure and in patients with elevated left ventricular filling pressure

Brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) plasma concentrations were measured in patients with dialysis-dependent chronic renal failure and in patients with coronary artery disease exhibiting normal or elevated left ventricular end-diastolic pressure (LVEDP) (n = 30 each). Blood samples were obtained from the arterial line of the arteriovenous shunt before, 2 h after the beginning of, and at the end of hemodialysis in patients with chronic renal failure. In patients with coronary artery disease arterial blood samples were collected during cardiac catheterization. BNP and ANP concentrations were determined by radioimmunoassay after Sep Pak C18 extraction. BNP and ANP concentrations decreased significantly (P < 0.001) during hemodialysis (BNP: 192.1 +/- 24.9, 178.6 +/- 23.0, 167.2 +/- 21.8 pg/ml; ANP: 240.2 +/- 28.7, 166.7 +/- 21.3, 133.0 +/- 15.5 pg/ml). The decrease in BNP plasma concentrations, however, was less marked than that in ANP plasma levels (BNP 13.5 +/- 1.8%, ANP 40.2 +/- 3.5%; P < 0.001). Plasma BNP and ANP concentrations were 10.7 +/- 1.0 and 60.3 +/- 4.0 pg/ml in patients with normal LVEDP and 31.7 +/- 3.6 and 118.3 +/- 9.4 pg/ml in patients with elevated LVEDP. These data demonstrate that BNP and ANP levels are strongly elevated in patients with dialysis-dependent chronic renal failure compared to patients with normal LVEDP (BNP 15.6-fold, ANP 2.2-fold, after hemodialysis; P < 0.001) or elevated LVEDP (BNP 6.1-fold, ANP 2.0-fold, before hemodialysis; P < 0.001), and that the elevation in BNP concentrations was more pronounced than that in ANP plasma concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in brain natriuretic peptide and atrial natriuretic peptide plasma concentrations during hemodialysis in patients with chronic renal failure

The present study aimed to investigate whether brain natriuretic peptide (BNP), atrial natriuretic peptide (ANP), cortisol and thyroid hormone concentrations change during hemodialysis in patients with chronic renal failure. Blood samples were withdrawn in 30 patients with chronic renal failure before hemodialysis, 2 hours after the beginning and at the end of hemodialysis. ANP and BNP concentrations were determined by radioimmunoassay after Sep Pak C18 extraction. Cortisol, T3, T4, FT4 and TSH serum concentrations were measured by enzyme immunoassay. BNP and ANP plasma levels were strongly elevated in patients with renal failure (BNP 22.4 fold, ANP 4.7 fold versus controls [n = 20]) and decreased significantly (p < 0.001) during hemodialysis (BNP [pg/ml]: 192.1 +/- 24.9, 178.6 +/- 23.0, 167.2 +/- 21.8; ANP [pg/ml]: 240.2 +/- 28.7, 166.7 +/- 21.3, 133.0 +/- 15.5). BNP plasma concentrations showed a stronger elevation than ANP plasma levels and a less pronounced decrease during hemodialysis (BNP: 13.5 +/- 1.8%, ANP: 40.2 +/- 3.5%, p < 0.001) which might in part be due to the longer half-life of BNP. Cortisol and TSH levels did not change significantly whereas T3, T4 and FT4 levels increased significantly (p < 0.001) during hemodialysis. Since corticosteroids and thyroid hormones stimulate natriuretic peptide release, these data suggest that the dialysis-induced decrease of ANP and BNP plasma concentrations is not augmented by a loss of cortisol or thyroid hormones during hemodialysis. The present data provide support that BNP and ANP plasma concentrations are sensitive indicators of the extracellular fluid volume status.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of corticotropin releasing factor on atrial natriuretic peptide release from the isolated perfused rat heart

The effect of corticotropin releasing factor (CRF) on atrial natriuretic peptide (ANP) release and its possible modulation by indomethacin, norepinephrine, propranolol and nitro-L-arginine (an inhibitor of the endothelium-derived relaxing factor (EDRF) release) was investigated, using an isolated perfused rat heart preparation. Bolus injection of 5 micrograms CRF, dissolved in 100 microliters perfusion buffer, provoked a significant (p < 0.01 vs. control) short-time increase of ANP release. Indomethacin (3 x 10(-5) mol/l) inhibited the CRF-stimulated increase of ANP release and decreased the basal ANP secretion (p < 0.01 vs. CRF group). Norepinephrine (10(-9) mol/l) slightly, but not significantly, decreased the CRF-stimulated ANP release and did not change the basal ANP output. Propranolol (3 x 10(-6) mol/l) did not alter ANP release. Nitro-L-arginine (3 x 10(-5) mol/l) increased the basal ANP release (p < 0.01 vs. CRF group) and prolonged the CRF-induced rise of the ANP secretion. The present data suggest that prostaglandins are important mediators of basal and CRF-stimulated ANP release and that EDRF might be a physiological inhibitor of ANP release.

Künstliche Sauerstoffträger – Perfluorkarbone

In der vorliegenden Arbeit werden chemische, physikalische und physiologische Eigenschaften von modernen perfluorierten Kohlenstoffen dargestellt, die als künstliche Sauerstoffträger im biologischen und medizinischen Bereich eingesetzt werden. Die Charakterisierung dieser Substanzen wird sowohl in historischer als auch in aktueller Hinsicht dahingehend präzisiert, daß die Anwendungsgebiete und die Limitierungen der Anwendung aufgezeigt werden. Wegen der multifunktionalen Eigenschaft von Blut ist heute unstrittig, daß kein künstlicher «Sauerstofftransporter» für den generellen Blutersatz denkbar ist. Ein besonderer Vorteil der Perfluorkarbone für den biologischen und medizinischen Einsatz liegt in der niedrigen Viskosität, die – gerade bei Stasezuständen – noch eine Verbesserung der Perfusion ermöglicht. Es treten keine immunologischen Probleme auf, und die Infektionsgefahren sind im Vergleich zu biologischem Material ausgeschaltet. Die wichtigsten Einsatzgebiete der Perfluorkarbone sind die Organperfusion bei Organbanken, die Oxygenierung von Zellkulturen sowie die Diagnostik mit bildgebenden Verfahren.

Metabolic and haemodynamic effects of dopamine plus domperidone in volunteers

There are no studies of the relationship between infusion rate of dopamine and the arterial and venous dopamine plasma concentration and the resulting haemodynamic and metabolic effects. Dopamine was administered to seven volunteers using five infusion rates (1, 3, 6, 9, 13 micrograms/kg per minute) in an escalating sequence lasting for 30 min for each step. Since dopamine can cause nausea and vomiting, this relationship was investigated after administration of domperidone for infusion rates above 3 micrograms/kg per minute. Haemodynamic effects were assessed using 2-dimensional echocardiography. During the highest infusion rate the arterial plasma dopamine concentration reached 1,379 +/- 181 nmol/l. There was a linear correlation between the dopamine infusion rate and both the arterial and the venous plasma concentration. There was no significant change in heart rate or diastolic blood pressure. Systolic blood pressure, ejection fraction and cardiac index increased in a dose-dependent manner. Systemic vascular resistance decreased during the two low doses of dopamine and was not different from baseline values during the three high infusion rates. The plasma concentrations of glucose and non-esterified fatty acids increased from 5.3 +/- 0.4 to 0.68 +/- 0.9 nmol/l, and from 360 +/- 119 to 971 +/- 307 mumol/l, respectively, during the 13 micrograms/kg per minute infusion rate. As the plasma noradrenaline concentration increased up to 7.84 +/- 2.46 nmol/l in correlation to the dopamine plasma concentration, an indirect sympathomimetic effect may contribute to the actions of dopamine plasma concentration.

Effects of norepinephrine, epinephrine, and dopamine infusions on oxygen consumption in volunteers

OBJECTIVE

To determine the relationships between plasma concentrations of norepinephrine, epinephrine, and dopamine and oxygen consumption (VO2) during infusion of these catecholamines.

DESIGN

Prospective, randomized variable dose, pharmacologic study in which a noncumulative infusion-rate design was used.

SETTING

Laboratory of the Department of Anesthesiology at a University Hospital.

PATIENTS

Twenty-one normal volunteers.

INTERVENTIONS

After a control period of 20 mins, norepinephrine (three infusion rates; 0.06 to 0.2 microgram/kg/min; n = 7), epinephrine (four infusion rates; 0.02 to 0.2 microgram/kg/min; n = 7), or dopamine (three infusion rates; 3 to 12 micrograms/kg/min; n = 7) was administered to normal volunteers (n = 21) for the purpose of constructing plasma concentration/VO2 response curves.

MEASUREMENTS AND MAIN RESULTS

Systolic and diastolic blood pressure, heart rate, plasma concentrations of norepinephrine, epinephrine, and dopamine, and VO2 were measured at the end of the control period and at the end of each catecholamine infusion. VO2 was measured using a ventilated canopy system and a differential oxygen sensor. Typical hemodynamic responses to vasopressors were seen during adrenergic receptor agonist infusions. VO2 increased from 132 +/- 7 to 153 +/- 10 mL/min/m2 during the highest infusion rate of norepinephrine, from 133 +/- 7 to 182 +/- 11 mL/min/m2 during the highest infusion rate of epinephrine, and from 132 +/- 13 to 163 +/- 8 mL/min/m2 during the highest infusion rate of dopamine (p < .05; paired t-test). Increases in VO2 were correlated with the logarithms of the corresponding plasma catecholamine concentrations. Effects on VO2 and hemodynamic responses occurred at similar plasma concentrations for each of the three catecholamines.

CONCLUSIONS

Administration of norepinephrine, epinephrine, or dopamine results in marked increases in VO2 in volunteers. In patients, the administration of catecholamines or sympathomimetics to attain optimal values of cardiac index, oxygen delivery (DO2), and VO2 may increase the oxygen demand and thus obscure the DO2-VO2 relationship.