Andrzej Szczudlik

DETERMINATION OF NITRITE/NITRATE IN HUMAN BIOLOGICAL MATERIAL BY THE SIMPLE GRIESS REACTION

Since a number of pathological processes such as septic shock, inflammation, graft rejection, diabetes, etc. are associated with a release of nitric oxide (NO), rapid and accurate methods of monitoring of NO concentration are of interest. Various methods for measurement of nitrite and nitrate (NO2-, NO3- ) -- the stable metabolites of NO -- are commonly used for this purpose. In this paper we have shown that the proper Griess procedure for nitrite determination significantly increases the sensitivity of this method. This procedure, supplemented with deproteinization and reduction of nitrates to nitrites in the presence of NADPH-sensitive reductase, can be successfully applied for measurement of NOx levels in human body fluids (serum, urine and CSF). Deproteinization of samples with methanol/diethylether is required and does not influence the sensitivity of detection of NO metabolites. The recovery of the method is 88%+/-6% (n = 30). The NOx concentrations measured by this procedure ranged from 25.0 to 39.0 micromol/l in blood, 4.6 to 14.6 micromol/l in CSF and 0.37 to 2.52 mmol/l (adjusted to creatinine concentration) in urine. The coefficient of variation for this method was between 1.3-2.2%. This method can also be recommended for measurement of NOx produced by cells in tissue cell culture.

Paraoxonase gene polymorphisms and sporadic ALS

Background: The human paraoxonase (PON) gene family consists of three members, PON1, PON2, and PON3, located adjacent to each other on chromosome 7. PON catalytic activity may be influenced by frequent amino acid variants. Chronic exposure to certain chemicals or to environmental factors causing enhanced lipid peroxidation metabolized by paraoxonases may be a risk factor for sporadic ALS (sALS). Objective: The aim of this study was to examine the association between PON1 Q192R, PON1 L55M, and PON2 C311S functional polymorphisms and the risk of sALS in a Polish population. Methods: The authors included 185 patients with a definite or probable diagnosis of sALS (El Escorial Criteria) and 437 healthy controls of similar age and gender. The paraoxonase polymorphisms were studied by PCR and restriction enzyme digestion. Results: Using logistic regression analyses, the C allele of the C311S polymorphism was associated with sALS in dominant and additive models, whereas the R allele of the Q192R polymorphism was associated with sALS in recessive, additive, and dominant models. The authors compared the distribution of haplotypes between cases and controls. The R-C haplotype was overrepresented among cases (odds ratio 3.44, 95% CI: 1.55 to 7.62, p = 0.002). Conclusions: Frequent amino acid variants in the paraoxonase 1 and paraoxonase 2 genes are associated with sporadic ALS in a Polish population.

Intracerebral hemorrhage triggers interleukin-6 and interleukin-10 release in blood.

Background and Purpose— Acute brain insult can cause systemic anti-inflammatory response, including anti-inflammatory cytokine release. The goal of this study was to determine the serum level of interleukin-6, interleukin-10, and interleukin-13 in patients with intracerebral hemorrhage and to correlate cytokine concentrations with stroke severity. Methods— Thirty patients with intraparenchymal hemorrhage and 16 control subjects were included. Serum samples were collected on the second day of hemorrhagic stroke. Cytokine level was measured with the enzyme-linked immunosorbent assay method. Results— Increased serum levels of interleukin-6 and interleukin-10 were detected in stroke patients. Interleukin-6 and interleukin-10 levels were significantly correlated with Glasgow Coma Scale score. In addition, interleukin-6 level correlated with blood volume and mass effect. Conclusions— Intracerebral hemorrhage is associated with systemic release of anti-inflammatory cytokines.

Activation of MAP kinase (ERK-1/ERK-2), tyrosine kinase and VEGF in the human brain following acute ischaemic stroke.

We examined expression of vascular endothelial growth factor (VEGF), phosphorylation of mitogen activated protein kinase (MAP) kinase (ERK1 and ERK2) and tyrosine phosphorylation in 19 patients (aged 58–90 years; mean 75) who died 1–44 days after acute ischaemic stroke. In the grey matter penumbra, 13 of 19 patients showed an increase in MAP kinase tyrosine phosphorylation (ERK1; 2.0- to 8-fold, ERK2; 2.2- to 11-fold) compared with normal contralateral tissue. In almost all cases, ERK-2 phosphorylation was higher than ERK1. Of these 13 patients, 11 also showed a general increase in tyrosine kinase phosphorylation, and eight expressed increased levels of VEGF protein (2.5- to 5-fold). In tissue examined directly from the infarct core, activation of the above proteins was not observed in the, majority of patients. In the white matter, seven of 19 patients (penumbra), and nine of 19 patients (stroke) had an increase in MAP kinase tyrosine phosphorylation (ERK1; 2.0- to 4.6-fold and ERK-2; 2.3- to 5.4-fold respectively) compared with normal contralateral tissue. There was no relationship between activation of MAP kinase and expression of VEGF. Examination of phosphorylated MAP kinase by immunohistochemistry revealed an increase in immunoreactivity in neurones, astroglial cells, reactive microglia and endothelial cells in areas surrounding infarcts, especially in areas with the highest density of microvessels. In conclusion, chronic activation of tyrosine phosphorylated events, in particular redistribution and phosphorylation of MAP kinase (ERK1/ERK2) occurs consistently in the grey matter penumbra of brain tissue following ischaemic stroke, and may be associated with increase in expression of VEGF. These signal transduction events could be important determinants of the extent of neuronal survival and/or angiogenic activity in the recovering brain tissue.

Gene Expression Profiles in Human Ruptured and Unruptured Intracranial Aneurysms: What Is the Role of Inflammation?

Background and Purpose— Mechanisms underlying development and rupture of intracranial aneurysms (IA) are poorly recognized. The majority of studies on human tissue have focused on predefined pathways. We sought to analyze global gene expression patterns of ruptured IA, unruptured IA, and control vessels. Methods— Transcription profiles were studied in human ruptured (n=8) and unruptured (n=6) IA, as well as in control intracranial arteries (n=5), using oligonucleotide microarrays. Real-time reverse-transcription polymerase chain reaction was used for confirmation. Functional analysis for determination of over-represented ontological groups among gene expression profiles was also performed. Results— The expression of 159 genes differed among the studied groups. Compared to the controls, 131 genes showed common directions of change in both IA groups. The most impacted biological processes for IA are: (1) the muscle system; (2) cell adhesion (downregulation); and (3) the immune system and inflammatory response (upregulation). Ruptured and unruptured IA differed in genes involved in immune/inflammatory processes; expression was reduced in ruptured IA. Conclusions— Decreased expression of genes related to muscle system and cell adhesion is important for the development of IA. The role of immune/inflammatory processes is unclear. Inflammation may participate in the healing process within IA while playing a protective role against IA rupture.

Neurochemical changes induced by acute and chronic administration of 1,2,3,4-tetrahydroisoquinoline and salsolinol in dopaminergic structures of rat brain.

The finding that endogenous tetrahydroisoquinolines may be involved in the etiology of Parkinsons disease suggests that their administration may cause changes resembling those observed in parkinsonian brain. We tested, using a high-performance liquid chromatography method, how single and chronic administration of 1,2, 3,4-tetrahydroisoquinoline and salsolinol affects dopamine and serotonin metabolism in the neurons of extrapyramidal and mesolimbic dopaminergic systems. We report that chronic administration of tetrahydroisoquinoline and salsolinol causes a decrease in a dopamine metabolism: the effect of tetrahydroisoquinoline was limited to the striatum, while salsolinol caused also a dramatic decline of dopamine level in the substantia nigra. The effect of both compounds on serotonin metabolism was small or absent. The tetrahydroisoquinolines produced no changes in the nucleus accumbens. The results indicate that tetrahydroisoquinoline and salsolinol specifically affect the nigrostriatal dopamine system, but only when administered chronically, and thus are compatible with the view that endogenous tetrahydroisoquinolines may participate in pathogenesis of Parkinsons disease.

Fibrin clot properties in acute ischemic stroke: relation to neurological deficit

INTRODUCTION Hypercoagulable state occurs in patients with acute vascular events. We wondered whether clot structure/function is altered in acute ischemic stroke (AIS), like in acute myocardial infarction. PATIENTS AND METHODS In 45 consecutive patients with AIS (24M, 21F), aged 67.4+/-10.9 years, and 45 healthy controls matched for age and sex, we investigated plasma fibrin clot structure/function by permeation, turbidity, and efficiency of fibrinolysis. RESULTS Compared to controls, AIS patients produced clots that had 30.5% less porous network (p<0.0001), were less susceptible to fibrinolysis (10.8% longer lysis time, p=0.001), were 20.5% more compact (p<0.0001), had 17.1% higher clot mass (p<0.0001), and showed increased (by 10.2%) overall fiber thickness (p<0.0001) with 8% shorter lag phase of fibrin formation (p=0.0002). Maximum rate of D-dimer release from clots was similar. Multiple regression analyses for all subjects (n=90) showed that being a stroke patient (p<0.0001), fibrinogen (p<0.0001) and lipoprotein(a) (p=0.0075) were independent predictors of clot permeability (model R2 0.79). Only fibrinogen (p<0.0001) and lipoprotein(a) (p=0.0026) predicted lysis time. All other fibrin parameters were predicted only by being a stroke patient. Clot compaction was associated with neurological deficit on admission (r=-0.81; p<0.0001) and at discharge (r=-0.69; p<0.0001). Patients with 0 or 1 point in the modified Rankin scale (n=19) had 13.3% higher clot permeability compared to the remainder (p=0.02). CONCLUSIONS This study is the first to show that AIS is associated with unfavorably altered fibrin clot properties that might correlate with neurological deficit.

Hypercortisolemia in acute stroke is related to the inflammatory response

Hypercortisolemia is thought to be a marker of the stress response following stroke. The aim of this study was to investigate the prevalence and prognostic significance of hypercortisolemia. The circadian variation of cortisol level and the relationship between serum cortisol levels and other stress, inflammatory, and haemostatic markers were also investigated. Seventy consecutive patients with their first ischemic stroke and 24 age- and sex-matched controls were included in the study. Serum cortisol levels (at 6:00 AM, 10:00 AM, 6:00 PM, and 10:00 PM), 24-h urine catecholamine excretion, beta-thromboglobulin levels, and other standard biochemical and haematological parameters were measured on the first day of hospitalisation and in control subjects. Outcome measures used the Barthel Index at Day 30, as well as 30- and 90-day mortality rates. Hypercortisolemia, defined as at least two of the four measurements above the normal range of serum cortisol levels (i.e. >618 nmol/l from the morning samples and >460 nmol/l from the evening samples) was found in 25 (35.7%) of the acute stroke patients and in 3 (12.5%) of the controls (p<0.05). Hypercortisolemia was associated with older age, greater severity of neurological deficit, larger ischemic lesions on CT, and worse prognoses (p<0.05). The study did not find a correlation between serum cortisol levels and other markers of the stress response such as catecholamines excretion and glucose levels. A significant correlation between serum cortisol levels and some markers of the inflammatory response, such as fever, fibrinogen level, white blood cell (WBC) count, and beta-thromboglobulin level, was established in stroke patients. Prognostic significance of hypercortisolemia in acute stroke patients seems to be related to the inflammatory response rather than to the stress response.

Beta-blockers reduce the risk of early death in ischemic stroke

OBJECTIVES Beta-blockers reduce mortality in patients after myocardial infarction. Experimental studies suggest that beta-blockers have also neuroprotective properties. The aim of this study was to assess if use of beta-blockers is associated with reduced risk of early death in ischemic stroke patients. MATERIALS AND METHODS Retrospective data analysis of 841 consecutive patients with acute ischemic stroke admitted to the stroke unit within 24 h after stroke onset. RESULTS 10.6% of patients received beta-blockers during hospitalization. Thirty-day case fatality was significantly lower in patients treated with beta-blockers than in those not treated with beta-blockers (6.8% versus 19.0%, P < 0.01). After adjustment for other prognostic factors, the use of beta-blockers was associated with reduced risk of early death (relative hazard 0.37, 95% confidence interval 0.16-0.84) independently of age, stroke severity, fasting glucose, total cholesterol level and pneumonia. When patients who died of cardiovascular causes were excluded from the analysis, the use of beta-blocker was no longer significantly associated with risk of death (P = 0.12). CONCLUSION In a retrospective series the use of beta-blockers was associated with reduced risk of early death in patients with ischemic stroke.

Microalbuminuria in nondiabetic patients with acute ischemic stroke: prevalence, clinical correlates, and prognostic significance.

Microalbuminuria is a frequent finding in several acute clinical conditions and predicts poor outcome; its role in acute ischemic stroke, however, is unknown. This study was designed to investigate the prevalence and predictive power of microalbuminuria in acute stroke patients and to establish the relationship between microalbuminuria and the patients’ clinical status. We studied 60 patients admitted within 24 h of their first ischemic stroke, 50 patients with a history of ischemic stroke, and 30 control subjects without known cerebrovascular diseases. Neurological deficit was assessed by the Scandinavian Stroke Scale (SSS) on admission and on days 1, 7, 14, and 30. Urinary albumin excretion was measured using immunonephelometric method, with 24-hour collections performed on day 2. Outcome was assessed by 30-day, 90-day and 1-year mortality. Microalbuminuria was found in 46.7% of patients with acute stroke, 16% of subjects with a history of stroke, and 16.7% of controls. On admission, acute stroke patients with microalbuminuria had more severe neurological deficit (median of SSS score on admission was 28 vs. 40, and on day 1, 22 vs. 39, both p < 0.05; Mann-Whitney U test) and more often had a decreased level of consciousness (32 vs. 10%, p < 0.05; Fisher exact test). Mortality was higher in the group of patients with microalbuminuria in acute stroke (21 vs. 3% after 30 days, 39 vs. 6% after 90 days and 50 vs. 9% after 1 year, p < 0.05 for all differences; Fisher exact test). In logistic regression analysis, microalbuminuria was found to be an independent predictor of 1-year mortality after ischemic stroke (OR = 6.0; p = 0.022; 95% CI = 1.3–27.7).