Transient Howell-Jolly-body-like cytoplasmic inclusions in neutrophils after severe intoxication with alpha-lipoic acid.

After intravenous supplementation of an unintentionally high dose of the antioxidant alpha-lipoic acid (ALA), a 53-year-old female complained of myalgia, chills and nausea, and showed signs of haemorrhagic diathesis. The laboratory findings were excessive hyperferritinemia, leukoerythroblastosis, severe thrombocytopenia, elevated liver enzymes and impaired coagulation. The toxicological tests resulted in an ALA serum concentration of 10 280 µg/L. The peripheral blood film of the patient showed some neutrophil dysplasia with unusual small dark-blue stained round cytoplasmic inclusions resembling 'Howell-Jolly-body-like' (HJBL) cytoplasmic inclusions, aptly named due to the morphologic similarity to their erythrocytic counterparts. Such HJBL inclusions are occasionally associated with acquired immunodeficiency, or immunosuppressive or cytostatic treatment. An association with ALA intoxication has not been described before. There are only a few reports on unintentional, harmful and lethal intoxications with ALA. The underlying molecular background of its toxicity on liver function or haematopoiesis is not yet known in detail, but ALA seems to interact with enzyme functions, e.g. with mitochondrial enzyme-complexes, possibly due to its pro-oxidant potential at high doses.

Inhibition of agonist-induced platelet aggregation by magnesium sulfate warrants its use as an alternative in vitro anticoagulant in pseudothrombocytopenia.

MgSO4 is effective in preventing spontaneous in vitro platelet agglutination in anticoagulant-induced pseudothrombocytopenia (PTCP). In order to learn more about its potential as an in vitro anticoagulant, platelets from MgSO4-anticoagulated blood were stimulated by several differentially-acting agonists (ADP, ARA, TRAP, epinephrine, collagen and ristocetin). Platelet aggregation in blood samples from 11 and 17 volunteers was measured by light-transmission aggregometry (LTA) according to Born and impedance aggregometry (MultiplateTM), respectively. Agonist-induced platelet aggregation was markedly lower in MgSO4-anticoagulated samples when compared with citrate-anticoagulated samples (decrease of 95.75% (ristocetin), 69.02% (collagen) and 75.73% (epinephrine)) or hirudin-anticoagulated samples (decrease of 85.99% (ADP), 80.98% (ARA), 77.24% (ristocetin), 54.37% (collagen) and 50.14% (TRAP)). The anti-aggregatory effect of MgSO4 is dose-dependent and readily detectable at a concentration of 7.5 mmol/l. Analysis of the agonist signaling pathways suggest that MgSO4 interferes with the final step of platelet aggregation, namely the intracellular mobilization of Ca2+.

Performance of the XN-2000 WPC channel-flagging to differentiate reactive and neoplastic leukocytosis.

BACKGROUND: The distinction between reactive and neoplastic leukocytes, especially atypical lymphocytes suspected to be reactive or neoplastic, is a particular challenge in automated hematological cell differentiation. The aim of the study was to evaluate the performance of the XN analyzer supplemented with the WPC channel for differentiating between reactive and neoplastic leukocytosis. METHODS: Blood samples of 253 patients with viral infections, lymphoma or leukemia were analyzed by the Sysmex XN-2000 analyzer equipped with the WPC channel. The results were compared to routine leukocyte differentiation using the routine Sysmex XE-2100 analyzer and automated digital microscopy (DM96). The combined information from standard morphology, immune phenotyping and clinical diagnosis served as a reference. RESULTS: The XN WPC channel demonstrated an excellent performance for differentiating neoplastic (AUC=0.933) and reactive leukocytosis (AUC=0.900) as compared to morphological smear examination (AUC=0.949 and AUC=0.968, respectively) or to the differentiation results of our routine hematology analyzer (AUC=0.630 and AUC=0.635, respectively). CONCLUSIONS: Our data show that the combined WDF/WPC of the Sysmex XN-Series analyzer is advantageous in the automated differentiation of neoplastic and reactive leukocytosis, thus supporting the correct diagnostic decision in the daily laboratory routine.

Exclusion of thrombocytopenia as a contraindication for invasive radiofrequency ablation in a patient with paroxysmal atrial fibrillation by using magnesium anticoagulation instead of EDTA: another case of anticoagulant-induced pseudo-thrombocytopenia.

Thrombocytopenia might be an exclusion criterion for invasive radiofrequency catheter ablation; therefore it is necessary to differentiate between pseudo-thrombocytopenia and a low platelet count due to other etiologies.A 69-year-old female presented to the cardiology department with recurrent atrial fibrillation that was resistant to conventional drug treatment. The initial laboratory findings were within the normal ranges, except for low platelet counts that occurred without a specific bleeding history. The reason for thrombocytopenia was anticoagulant-induced in vitro aggregation of platelets in the presence of EDTA as well as in citrated blood samples. As recently communicated, magnesium anticoagulated blood samples prevent platelet aggregation in individuals with anticoagulant-associated pseudo-thrombocytopenia. Although its aggregation-inhibiting effect is known from previous clinical observations, magnesium sulphate has not been introduced as an anticoagulant in analytical medicine.Based on our observations, blood anticoagulated with magnesium sulphate is recommended to verify low routine platelet counts before final clinical decisions are made.

Effective estimation of correct platelet counts in pseudothrombocytopenia using an alternative anticoagulant based on magnesium salt.

Pseudothrombocytopenia remains a challenge in the haematological laboratory. The pre-analytical problem that platelets tend to easily aggregate in vitro, giving rise to lower platelet counts, has been known since ethylenediamine-tetra acetic acid EDTA and automated platelet counting procedures were introduced in the haematological laboratory. Different approaches to avoid the time and temperature dependent in vitro aggregation of platelets in the presence of EDTA were tested, but none of them proved optimal for routine purposes. Patients with unexpectedly low platelet counts or flagged for suspected aggregates, were selected and smears were examined for platelet aggregates. In these cases patients were asked to consent to the drawing of an additional sample of blood anti-coagulated with a magnesium additive. Magnesium was used in the beginning of the last century as anticoagulant for microscopic platelet counts. Using this approach, we documented 44 patients with pseudothrombocytopenia. In all cases, platelet counts were markedly higher in samples anti-coagulated with the magnesium containing anticoagulant when compared to EDTA-anticoagulated blood samples. We conclude that in patients with known or suspected pseudothrombocytopenia the magnesium-anticoagulant blood samples may be recommended for platelet counting.

Ceruloplasmin expression in renal cell carcinoma correlates with higher-grade and shortened survival.

Aim: We aimed to explore ceruloplasmin (CP) expression in clear cell renal cell carcinoma (ccRCC). Materials & methods: CP was analyzed in biofluid samples of 63 ccRCC patients, divided into three grading groups, and immunohistochemically, in 308 ccRCC. Results: Significant differences of mean plasma and urine CP levels in different grading groups were found. CP immunoreactivity was significantly linked to high-grade disease. Log rank tests showed a significant shorter overall survival rate in CP-positive cases (all p < 0.05). Conclusion: CP protein levels in biofluid samples confirmed differential CP expressions, depending on nuclear grade in ccRCC as previously seen in RNA expression analysis. CP expression was linked to high-grade disease and reduced survival rate in RCC.

The European Register of Specialists in Clinical Chemistry and Laboratory Medicine: guide to the Register, version 3-2010.

In 1997, the European Communities Confederation of Clinical Chemistry and Laboratory Medicine (EC4) set up a Register for European Specialists in Clinical Chemistry and Laboratory Medicine. The operation of the Register is undertaken by a Register Commission (EC4RC). During the last 12 years, more than 2200 specialists in Clinical Chemistry and Laboratory Medicine have joined the Register. In 2007, EC4 merged with the Forum of European Societies of Clinical Chemistry and Laboratory Medicine (FESCC) to form the European Federation of Clinical Chemistry and Laboratory Medicine (EFCC). Two previous Guides to the Register have been published, one in 1997 and another in 2003. The third version of the Guide is presented in this article and is based on the experience gained and development of the profession since the last revision. Registration is valid for 5 years and the procedure and criteria for re-registration are presented as an Appendix at the end of the article.

Renal Insufficiency Following Radiocontrast Exposure Trial (REINFORCE): a randomized comparison of sodium bicarbonate versus sodium chloride hydration for the prevention of contrast-induced nephropathy.

INTRODUCTION: For the prevention of contrast-induced nephropathy (CIN) after coronary angiography, hydration by 0.9% sodium chloride solution and N-acetylcysteine is currently recommended. However, it is unclear whether volume supplementation with sodium bicarbonate is better than with sodium chloride when used in conjunction with nonionic, low-osmolar iopamidol. The aim of this study was to analyze and compare the effects of sodium bicarbonate and sodium chloride on renal function in 145 patients exposed to nonionic iso-osmolar contrast medium iodixanol in a randomized study. PATIENTS AND METHODS: Renal Insufficiency Following Radiocontrast Exposure is a prospective, randomized, single-center, double-blinded trial of 145 patients (age 72.6+/-6.7 years) with elevated baseline serum creatinine levels (mean 132.6+/-29.3 micromol/l). Eligible patients were randomized to either a 154 mEq/l infusion of sodium bicarbonate (n=71, group I) or sodium chloride 0.9% solution (n=74, group II). The primary endpoint was serum creatinine elevation beyond 25% or 44 micromol/l on the first or second day following exposure to the contrast medium. Serum creatinine, serum cystatin C, plasma viscosity, urinary enzymes alanine aminopeptidase and N-acetyl-beta-D-glucosaminidase, and alpha1-microglobulin were measured at baseline and on days 1 and 2 after contrast medium administration. RESULTS: An overall proportion of five CIN (3.4%) was observed with equal distribution among the groups (4.2% in sodium bicarbonate group vs. 2.7% in sodium chloride group; P=0.614). Parameters of renal function demonstrated no differences between the two hydration regimens on day 1 after angiography; even on day 2 most parameters were similar in groups I and II. CONCLUSION: Renal Insufficiency Following Radiocontrast Exposure demonstrates a homogeneously low rate of CIN after exposure to nonionic, iso-osmolar iodixanol regardless of the use of either bicarbonate sodium or sodium chloride solution for volume supplementation. Low-toxicity contrast media and any hydration may offset potential antioxidant effects of sodium bicarbonate.

Hydrogen peroxide-induced activation of defense mechanisms against oxidative stress in rat pancreatic acinar AR42J cells.

Oxidative stress has been implicated in the pathogenesis of acute pancreatitis. Generally, cells respond to oxidative stress with adaptive changes in gene expression aimed at preventing cellular damage and increasing their survival. However, the overall extent of these genetic changes remains poorly defined. This issue was, therefore, examined in the current study. Following exposure of rat pancreatic AR42J cells to 0.08 mM hydrogen peroxide (H(2)O(2)), a concentration failing to induce necrotic cell death, the expression of 96 stress-related genes was monitored by cDNA microarray analysis. H(2)O(2) provoked a time-dependent reorientation of 54 genes. In particular, at 6 and 24 h, 27 and 11 genes were induced, whereas 10 and 6 genes were suppressed, respectively, showing that the degree of change was stronger at the early time point, and that the number of up-regulated genes was obviously larger than the number of down-regulated genes. Reverse transcription-PCR for selected genes confirmed the gene expression pattern. Many of the differentially up-regulated genes can be related to the antioxidant enzymatic defense system, to cell cycle arrest, to repair and/or replacement of damaged DNA, to repair of damaged protein, and to activation of the NF-kappaB pathway. The results suggest that AR42J cells respond to sublethal oxidative stress with transient transcriptional activation of multiple defense mechanisms that may be an indication for a complex adaptation process. An understanding of the cellular stress responses may lead to new insights into the pathogenesis of oxidative stress-related diseases including acute pancreatitis.

Platelet and plasma BDNF in lower respiratory tract infections of the adult.

Enhanced bronchial responsiveness during and following lower respiratory tract infections is a major clinical problem, but its pathogenesis is poorly understood. Brain-derived neurotrophic factor (BDNF), which can be released by platelets and leukocytes, has been identified as a mediator of bronchial hyperresponsiveness. It is unknown whether the release of BDNF is altered during lower respiratory tract infections of the adult. In this clinical pilot study, 16 patients (35-80 years old) with the diagnosis of an acute bacterial lower respiratory tract infection and elevated serum concentrations of c-reactive protein (>100 microg/ml) and procalcitonin (>0.1 ng/ml) were examined on admission to the hospital and 1 week after antibiotic treatment. Sixteen age- and sex-matched controls were examined in the same time period. BDNF concentrations in serum and platelets, but not in plasma, were markedly reduced in patients on the day of admission (median <25% of the controls). Analysis of the platelet marker serotonin (5-HT) suggested that the decrease of platelet BDNF is part of a non-specific release of platelet-derived mediators in this condition. Clinical improvement was accompanied by a restoration of serum and platelet BDNF concentrations which returned to control levels after 1 week of treatment. Cell culture experiments revealed that bacterial lipopolysaccharide (LPS) enhanced the release of BDNF by peripheral blood mononuclear cells of the patients at both time points. In conclusion, these data suggest that lower respiratory tract infections might be associated with an augmented release of BDNF by platelets and mononuclear cells.

Maternal serum concentrations of BDNF and depression in the perinatal period.

There is accumulating evidence that a deficiency in brain-derived neurotrophic factor (BDNF) plays a critical role in the pathophysiology of depression. This is in line with the postulate that low BDNF levels in serum are associated with depression. However, the regulation of maternal BDNF serum levels in the perinatal period, and its relationship to maternal depression is unknown. In this study, serum BDNF concentrations were measured in 40 pregnant (follow-up: 30th and 37th week of gestation, 1 week and 8 weeks after childbirth) and 40 non-pregnant women (20-40 years old). The Edinburgh Postnatal Depression Scale (EPDS) was assessed in all subjects at all time points. Maternal serum levels of BDNF were markedly decreased, both before and after childbirth (median: <30% of non-pregnant controls). BDNF correlated with decreased Serotonin (5-HT) levels in serum (r>0.6 and p<0.001 at all time points). In contrast, there was no association with altered estrogen, progesterone, dehydroepiandrosterone or cortisol concentrations in serum. There were significantly higher cortisol levels in cases of maternal depression (EPDS scores>9 points) than in cases without depression. There was a trend to a decrease of BDNF and 5-HT levels in cases of maternal depression (as compared to cases without depression), but this was not significant. In conclusion, we demonstrate that women display markedly decreased BDNF serum levels before and after childbirth. This phenomenon might reflect an increased risk for the development of mood disorders in the perinatal period. However, the individual serum concentration of BDNF alone did not predict maternal depression in our study.

Magnesium Sulfate as an Alternative In Vitro Anticoagulant for the Measurement of Platelet Parameters?

OBJECTIVES: There are conflicting reports on the reliable measurement of platelet count and mean platelet volume (MPV) using EDTA or citrate. The anticoagulant properties of magnesium sulfate (MgSO4) are known from the literature. The aim of this study was to evaluate MgSO4 as an in vitro anticoagulant for platelet count, MPV, platelet distribution width, and platelet activation. METHODS: Whole blood from volunteers was anticoagulated by EDTA, citrate, or MgSO4 Platelets were counted by the XE 5000 (Sysmex, Norderstedt, Germany) impedance and fluorescence optical technique. RESULTS: The mean impedance platelet counts were 227.7, 197.0, and 201.1 × 10(9)/L in EDTA-, citrate-, or MgSO4-anticoagulated blood, respectively. The counts were 4.7% higher (EDTA) after 3 hours of storage but 4% lower in citrate-anticoagulated blood. The counts in magnesium samples remained stable. The MPV was 10.4 fL (EDTA), 9.5 fL (citrate), and 9.3 fL (MgSO4). EDTA samples showed cell swelling within the first 3 hours. This was lower in citrate and only marginal in magnesium samples. High activation of platelets was observed only in EDTA samples. CONCLUSIONS: Magnesium anticoagulation might be advantageous for more reliable MPV measurements. Although platelet count is underestimated when the impedance method is used, the platelet count reveals similar results when measured by the fluorescent optical method.

Measurement of Platelet Counts and Volume Using Magnesium Sulfate as an Anticoagulant: Comparison of Impedance and Light-Scatter Technology.

OBJECTIVES: Magnesium sulfate (MgSO 4 ) was recently reported as an alternative in vitro anticoagulant in pseudo-thrombocytopenia. Its suitability as an anticoagulant for the determination of reliable platelet parameters is the subject of this study. METHODS: Platelet count and mean platelet volume were measured in blood samples anticoagulated with EDTA and MgSO 4 and compared. The platelet parameters were determined by impedance (XE 5000 [Sysmex, Norderstedt, Germany]; DxH 800 [Beckman-Coulter, Krefeld, Germany]) and laser light-scatter technology (Advia 120 [Siemens Healthcare Diagnostics, Eschborn, Germany]). RESULTS: MgSO 4 anticoagulation underestimated platelet counts compared with EDTA. Mean platelet volume (MPV) in magnesium-anticoagulated blood was lower when measured by impedance but higher when light-scatter technology was used. Storage of the differently anticoagulated blood led to differently lower platelet counts after 24 hours, independent of the anticoagulant. In EDTA blood, the mean platelet volume increased moderately when measured by impedance but markedly when measured by laser light scatter. In MgSO 4 -anticoagulated blood, the MPV increase was negligible. CONCLUSIONS: Impedance technology and magnesium anticoagulation might be advantageous for standardizing MPV measurements, although the mean platelet count is slightly underestimated by both technologies.

The impact of age, weight and gender on BDNF levels in human platelets and plasma.

Brain-derived neurotrophic factor (BDNF) is a key mediator of neuronal plasticity in the adult. BDNF is known to be stored in human platelets and to circulate in plasma, but the regulation and function of BDNF in peripheral blood is still poorly understood. In this prospective study, we have examined 140 healthy, non-allergic adults (20-60 years old) to elucidate the impact of age and physical parameters on BDNF levels in human platelets and plasma. There was a wide concentration range of BDNF in serum (median: 22.6 ng/ml), platelets (median: 92.7 pg/10(6) platelets) and plasma (median: 92.5 pg/ml). BDNF levels in plasma decreased significantly with increasing age or weight, whereas platelet levels did not. When matched for weight, there were no significant gender differences regarding BDNF plasma levels. However, women displayed significantly lower platelet BDNF levels than men. In addition, platelet BDNF levels changed during the menstrual cycle. In conclusion, we demonstrate that parameters such as age or gender have a specific impact on stored and circulating BDNF levels in peripheral blood.

Expression of thrombospondin-1 in prostate-derived cell lines.

Thrombospondin-1 (TSP-1) is a multifunctional matricellular glycoprotein involved in several mechanisms critical to the formation and progression of solid tumors including cell adhesion, proliferation, migration, invasion, and angiogenesis. However, work related to TSP-1 expression and functionality in prostate cancer is limited. Expression experiments in the present study demonstrated lower expression of TSP-1 in the prostate cancer cell lines DU 145 and LNCaP compared to SV40-immortalized prostatic epithelial cells PNT 1A. All three cell lines expressed the TSP-1 receptor CD36. Exogenously added TSP-1 modulated the cellular phenotype of LNCaP cells, which demonstrated decreased proliferation rate and partly entered apoptosis. Collectively, these data support the concept that partial or complete loss of TSP-1 synthesis may provide tumor cells with a proliferation advantage. In addition, TSP-1 located at the border between tumor and stroma as observed in primary prostate tumors may act as a barrier of tumor growth depending on the TSP-1 receptor repertoire of the tumor cells.

Hemochromatosis gene HFE Cys282Tyr mutation analysis in a cohort of Northeast German hospitalized patients supports assumption of a North to South allele frequency gradient throughout Germany.

Hereditary hemochromatosis is the most common autosomal recessive disease in populations of Northern European ancestry. Population studies demonstrated highly variable frequencies of the HFE Cys282Tyr allele in various regions throughout Europe and decreasing allele frequencies from north to south. However, most of the German prevalence studies covered the central and southern regions of the country. The present study recruited 709 consecutive patients at the time of their admission to a Northeast German University Hospital Medical Department. Polymerase chain reaction-based assays were used to detect HFE Cys282Tyr and His63Asp alleles. Biochemical profiling consisting of transferrin saturation rate, and concentrations of ferritin, transferrin, and iron were performed in Cys282Tyr homozygotes and Cys282Tyr/His63Asp heterozygotes, respectively. Results were compared with previous German prevalence studies. Analysis of 709 Caucasian patients resulted in 650 (91.7%) homozygous HFE wild-type carriers, 55 (7.74%) Cys282Tyr heterozygotes, 4 (0.56%) Cys282Tyr homozygotes and 6 (0.85%) Cys282Tyr/His63Asp compound heterozygotes. The HFE Cys282Tyr allele frequency was 4.44%. Phenotypic markers of iron overload were elevated in one homozygote. We conclude that in contrast to previous hemochromatosis prevalence studies in Germany using blood donors or employees, the present study involving hospital patients estimated a HFE Cys282Tyr allele frequency of 4.44% and supports the emerging concept of an allele gradient decreasing from North to South within Germany.

Comparative evaluation of two newly developed devices for capillary viscometry.

Viscometry is an often applied method in clinical chemistry. A variety of studies demonstrate an association of parameters related to blood viscosity with human pathology of varying origin. Whole blood and plasma viscosity are considered to be clinically useful indicators in the diagnostic workup and therapy monitoring of certain diseases. In this study, we compare the "Waegeviskosimeter" (WV) described in previous publications with a newly developed device, the "Reverse Flow Viscometer" (RFV). Both viscometers are capillary flow viscometers. Both overcome the disadvantage of common viscometers of the Ubbelohde and Cannon-Fenske type which require large amounts of plasma and which can be only applied to Newtonian fluids. The accuracy of the measurements of both viscometers, requiring less than 1.0 ml sample volume, is superior to most conventional methods. The major distinction in the functionality of the WV and the RFV is that the WV measures the kinematic viscosity whereas the RFV directly estimates dynamic viscosity without the requirement of additional density measurement. We found good reproducibility of viscosity with coefficient of variation CV < or =1.1% for both viscometers. Quality assurance measures have been carried out. Because no quality assurance scheme according to the guidelines proposed by the German Medical Association exists for plasma or whole blood viscosity, we tested reference material Lyphochek Unassayed Chemistry Control Level 1 and Level 2 (Bio-Rad Laboratories). We determined the viscosities 1.40 mPa s and 1.08 mPa s (37 degrees C) and the between-run precision from daily quality control runs with CV of 1.4% and 1.2% for the WV, and 1.7% and 1.4% for the RFV. For direct comparison reasons, we determined the viscosity in seventy human plasma and serum samples by both methods. Using the regression analysis described by Passing-Bablok, the RFV and the WV methods are highly correlated and show only little variations (r = 0.990, tau = 0.896). The regression equation is y(WV) = 1.035x(RFV) - 0.056 with a mean deviation of 0.4+/-3.6%. We conclude that both new devices for viscosity assessment fulfill all quality requirements as prescribed for clinical chemical laboratories. One advantage RFV is to measure the dynamic viscosity directly.

Double transfection improves small interfering RNA-induced thrombin receptor (PAR-1) gene silencing in DU 145 prostate cancer cells.

The efficiency of small interfering RNA (siRNA)-induced gene knockdown is hampered by low transfection efficiency. We established a novel and simple double transfection method using specific siRNA duplexes targeted against human thrombin receptor PAR-1 in DU 145 prostate cancer cells. The initial siRNA transfection of cell suspensions followed by re-transfection of adherent cells on the following day resulted in undetectable PAR-1 mRNA and absent receptor protein. PAR-1 mRNA expression was silenced for up to five days. Functional studies showed that PAR-1 gene silencing in DU 145 cells abolished the modulating effects of thrombin on cell adhesion to the extracellular matrix proteins, fibronectin and laminin, thus demonstrating the essential role of PAR-1 in mediating thrombin effects on DU 145 cell adhesion.

Oxidative stress in phagocytes--"the enemy within".

Phagocytes represent a powerful defense system against invading microorganisms that threaten the life or functional integrity of the host. The capacity to generate and release substantial amounts of reactive oxygen species is a unique property of activated polymorphonuclear and mononuclear phagocytes. The crucial role of these molecules in killing microorganisms and their consecutive contribution to tissue damage during injury and inflammation is widely known. Although much research has been done to explore the molecular events involved in the interaction of oxygen intermediates with microbes or host tissue, surprisingly little attention has been paid to the effect of reactive metabolites on the phagocyte itself. This fact is especially surprising, since it is apparent that the activated phagocyte is directly exposed to its own toxic metabolites. The potential damage occurring during excessive radical formation might notably alter the vital functions of these primarily immunocompetent cells. Moreover, the critical role of oxygen radicals in apoptosis of leukocytes has been recently revealed. Apoptosis is now supposed to represent a key mechanism in neutrophil deactivation and resolution of inflammation. Therefore, this review will focus on the delicate balance between released oxidants and antioxidative protection within the phagocytes themselves. General and phagocyte-specific antioxidative mechanisms, which have co-evolved with the radical generating machinery of phagocytes, are discussed, since the outcome of local inflammation can directly depend on this antioxidative capacity and might range from adequate elimination of the pathogen with minimal acute tissue damage to progression towards a systemic inflammatory response syndrome.

Expression and regulation of calpain in rat pancreatic acinar cells.

INTRODUCTION: Calpains, cytosolic Ca(2+)-dependent cysteine proteases, are expressed in a variety of mammalian cells and have been found to participate in stimulus-secretion coupling in platelets and alveolar cells. AIMS: In pancreatic acinar cells, expression of calpains and their role in the secretory process have not yet been elucidated. Both subjects, therefore, were examined in the current study. METHODOLOGY: mu-calpain and m-calpain were detected immunochemically. Calpain activation was measured by fluorescence spectrophotometry and single-cell fluorometry using Suc-Leu-Leu-Val-Tyr-AMC as substrate. Amylase secretion and cell damage, characterized by lactate dehydrogenase release, were measured by colorimetric assays. RESULTS: Immunochemistry revealed cytoplasmic localization of both calpain isoforms. Immediately after increasing the cytosolic Ca(2+) concentration with ionomycin, a marked dose-dependent protease activation and cellular damage were observed. Inhibition of ionomycin-mediated enzyme activation through preincubation of cells with Ca(2+)-free medium, BAPTA-AM, or Z-Leu-Leu-Tyr-CHN(2) significantly reduced cell injury. Cholecystokinin (100 pM) also induced proteolytic activity, preceding cholecystokinin-stimulated amylase secretion. Protease activity and amylase release were significantly inhibited by Z-Leu-Leu-Tyr-CHN(2 ) retreatment. CONCLUSION: Calpains are expressed in pancreatic acinar cells and may participate in stimulus-secretion coupling. In addition, our study indicates that pathologic calpain activation may contribute to Ca(2+)-mediated acinar cell damage.