Isozymes of AMP-Deaminase in Muscles Myasthenia Gravis Patients.

Similar symptoms observed in Myasthenia gravis (MG) can be also detected in the case of skeletal muscle AMP-deaminase deficiency. We compared the activity and expression of AMP-deaminase (AMPD) products in skeletal muscles of MG patients and MG-free individuals. The activity of AMP-deaminase in the muscles of MG patients was significantly higher than in the controls and was 2.05 µmol/min/mg protein (±0.31). The two groups differ in level of AMPD product expression. Furthermore in MG-group molecular size of isoform AMPD1 is 90 kDa in contrast to MG-free group where is present 70 kDa isoform of enzyme. The data suggests that the disturbances in transmission of neuronal signaling, taking place in the skeletal muscles of MG patients, may also change energetic metabolism of the affected muscles by changing molecular mass of isoform.

Paraquat inhibits progesterone synthesis in human placental mitochondria.

INTRODUCTION: Human placenta mitochondria produces huge amounts of progesterone necessary for maintaining the pregnancy. Lipid peroxidation in human placental mitochondria inhibits progesterone synthesis and that inhibition can be reversed by superoxide dismutase and other antioxidants. Paraquat (PQ) a highly toxic herbicide generates superoxide radical inside cells and induces lipid peroxidation. Hence, it is supposed to stimulate lipid peroxidation in human placental mitochondria and in consequence to inhibit a placental mitochondrial steroidogenesis. METHODS: Placentas were obtained from normal pregnancies. All experiments were done using isolated human placental mitochondria. Mitochondrial lipid peroxidation was determined as tiobarbituric acid reactive substances (TBARS). A conversion of cholesterol to pregnenolone or pregnenolone to progesterone was measured using radiolabeled steroids and thin layer chromatography. RESULTS: PQ enhanced the iron-dependent lipid peroxidation as also PQ heightened the inhibitory action of this process on progesterone synthesis in isolated human placental mitochondria. Paradoxically, a superoxide dismutase (SOD) reversed the inhibition of progesterone synthesis only minimally although it strongly inhibited PQ stimulated iron-dependent lipid peroxidation. When iron was absent, PQ stimulated only negligible lipid peroxidation but strongly inhibited progesterone synthesis. SOD had no effect on inhibition of progesterone synthesis by PQ. PQ strongly inhibited of the conversion of cholesterol to pregnenolone but had not got any influence on the enzymatic activity of mitochondrial 3ß-hydroxysteroid dehydrogenase. PQ strongly decreased the efficiency of NADPH-dependent cytochrome P450 reduction as well as it promoted the rapid oxidation of the pre-reduced mitochondrial cytochrome P450. However PQ has not inhibited combined activity of adrenodoxin reductase and adrenodoxin. DISCUSSION: We conclude that the most important reason of the inhibition of progesterone synthesis by PQ is the escape of electrons from cytochrome P450scc to that compound what leads to cytochrome oxidation and, in consequence the inhibition of the reaction catalyzed by it. The action of PQ described here should be considered as potentially harmful for pregnancy and fetal development.

Effect of AMP-deaminase 3 knock-out in mice on enzyme activity in heart and other organs.

Recent findings suggest that inhibition of AMP-deaminase (AMPD) could be effective therapeutic strategy in heart disease associated with cardiac ischemia. To establish experimental model to study protective mechanisms of AMPD inhibition we developed conditional, cardiac specific knock-outs in Cre recombinase system. AMPD3 floxed mice were crossed with Mer-Cre-Mer mice. Tamoxifen was injected to induce Cre recombinase. After two weeks, hearts, skeletal muscle, liver, kidney, and blood were collected and activities of AMPD and related enzymes were analyzed using HPLC-based procedure. We demonstrate loss of more than 90% of cardiac AMPD activity in the heart of AMPD3-/-mice while other enzymes of nucleotide metabolism such as adenosine deaminase, purine nucleoside phosphorylase were not affected. Surprisingly, activity of AMPD was also reduced in the erythrocytes and in the kidney by 20%-30%. No change of AMPD activity was observed in the skeletal muscle and the liver.

AMP deaminase 1 gene polymorphism and heart disease-a genetic association that highlights new treatment.

Nucleotide metabolism and signalling is directly linked to myocardial function. Therefore analysis how diversity of genes coding nucleotide metabolism related proteins affects clinical progress of heart disease could provide valuable information for development of new treatments. Several studies identified that polymorphism of AMP deaminase 1 gene (AMPD1), in particular the common C34T variant of this gene was found to benefit patients with heart failure and ischemic heart disease. However, these findings were inconsistent in subsequent studies. This prompted our detailed analysis of heart transplant recipients that revealed diverse effect: improved early postoperative cardiac function associated with C34T mutation in donors, but worse 1-year survival. Our other studies on the metabolic impact of AMPD1 C34T mutation revealed decrease in AMPD activity, increased production of adenosine and de-inhibition of AMP regulated protein kinase. Thus, genetic, clinical and biochemical studies revealed that while long term attenuation of AMPD activity could be deleterious, transient inhibition of AMPD activity before acute cardiac injury is protective. We suggest therefore that pharmacological inhibition of AMP deaminase before transient ischemic event such as during ischemic heart disease or cardiac surgery could provide therapeutic benefit.

[Electronic poison information management system]. / Elektroniczny system zarzadzania informacja toksykologiczna.

We describe deployment of electronic toxicological information database in poison control center of Pomeranian Center of Toxicology. System was based on Google Apps technology, by Google Inc., using electronic, web-based forms and data tables. During first 6 months from system deployment, we used it to archive 1471 poisoning cases, prepare monthly poisoning reports and facilitate statistical analysis of data. Electronic database usage made Poison Center work much easier.

[Acute poisoning with sertindole--a case report]. / Ostre zatrucie sertindolem--opis przypadku.

The paper presents a case of acute, accidental sertindole poisoning. Intoxication had a stormy clinical course with symptoms of cardiovascular, respiratory and nervous system. A relatively small dose of ingested preparation and severe overdose course may indicate a low therapeutic drug index.

[Metabolic acidosis--cause of sudden, unexplained death among chronic alcohol abusers]. / Kwasica metaboliczna--przyczyna naglych, niewyjasnionych zgonów u nalogowych alkoholików.

Metabolic acidosis (lactic and ketoacidosis) are frequent cause of sudden, unexplained deaths of alcohol abusers with negative results of pathomorphological and toxicological determinations. We described the pathomechanism leading to the acidosis.

[Manganism--neurodegenerative brain disease caused by poisoning with manganese]. / Manganizm--choroba neurodegeneracyjna mózgu spowodowana zatruciem manganem.

Manganism is a neurodegenerative disease of brain caused by intoxication by manganese and its excessive accumulation in this tissue. Some of the clinical symptoms observed in this disease resemble these observed in Parkinson disease.

Suicidal intoxication with potassium chlorate successfully treated with renal replacement therapy and extracorporeal liver support.

We present a case of a 22-year-old male who, in a suicide attempt, ingested approximately 200 g of potassium chlorate. Upon admission to the hospital, he presented in full respiratory failure with cyanosis. Methylene blue antidote was given but found to be ineffective. The patient was intubated and mechanical ventilation was initiated. Because of renal failure with anuria, intermittent haemodialysis (iHD) followed by continuous venovenous hemodiafiltration (CVVHDF) was performed. His hospital stay was also complicated by hemolysis, disseminated intravascular coagulation, and atrial fibrillation. Transfusions of packed red blood cells, platelets, and fresh frozen plasma were necessary to correct the deficits. He also developed liver failure and required two sessions of molecular adsorbent recirculating system (MARS) therapy. On day 14 of his hospitalization, he regained consciousness, as well as full respiratory and circulatory function. There are no controlled studies addressing management of potassium chlorate poisoning. We suggest that early renal replacement therapy should be strongly considered.

Accidental intoxication with high dose of methoxetamine (MXE)--a case report.

UNLABELLED: Methoxetamine (MXE) is an analogue of ketamine. CASE REPORT: We present a 25-year-old male who, after getting an information from the Internet, started to use MXE to avoid the excitement connected with recreational codeine abuse. For about 8 - 10 months he injected about 100 mg of MXE intramuscularly. On the day of admission the patient decided to take much higher dose of 750 mg of MXE. For the first 3-4 hours of hospitalization the profound agitation, which demanded the usage of high doses of benzodiazepines, was observed every several minutes. After 6-7 hours of supportive treatment the patient returned to his baseline mental status. CONCLUSION: MXE presents the new healthcare threat because of easy accessibility via Internet, and lack of legal restrictions in many countries. The low dose of MXE can cause "peace and serenity", however, higher dose may act opposite.

[Reactive oxygen species and 3,4-dihydroxyphenylacetaldehyde in pathogenesis of Parkinson disease]. / Reaktywne formy tlenu i aldehyd 3,4-dihydroksyfenylooctowy w patogenezie choroby Parkinsona.

Reactive oxygen species, which plays a role in pathogenesis of many neurodegenerative diseases, seems to be important also in pathogenesis of the Parkinson's disease. Experiments performed recently, revealed in the cerebrum of patients suffering from this disease (induced by the oxidative stress) elevated levels of 3,4-dihydroxyphenylacetaldehyde (DOPAL)--a strong endogenous neurotoxin to dopamine neurons.

Melatonin enhances antioxidant action of alpha-tocopherol and ascorbate against NADPH- and iron-dependent lipid peroxidation in human placental mitochondria.

Human placental mitochondria might be a significant source of NADPH- and iron-dependent production of reactive oxygen species (ROS). Preeclampsia is believed to be a consequence of overproduction of ROS in human placenta. The experimental results presented here show that melatonin inhibits NADPH- and iron-dependent lipid peroxidation of human placental mitochondria in a concentration-dependent manner. At 1.5 mm concentration, melatonin suppressed this process nearly completely. Melatonin does not influence significantly the iron oxidation at this conditions, indicating that free radical scavenging rather than metal-chelating phenomenon is the basis of its antioxidant action. The fact of inhibition of lipid peroxidation by melatonin at conditions excluding iron participation also supports this hypothesis. Elucidation of the nature of common interaction among melatonin, ascorbate, and alpha-tocopherol in human placental mitochondria was the main aim of this study. In presence of 90 mum ascorbate, the inhibition of lipid peroxidation by melatonin was strong and had a feature of synergistic interaction. At presence of 30 mum ascorbate, which stimulated lipid peroxidation, melatonin caused a loss of pro-oxidant effect of ascorbate. While the interaction of melatonin with ascorbate indicated synergism, the joint action of melatonin and alpha-tocopherol was additive. When all three antioxidants were applied together, the strongest inhibition of lipid peroxidation was observed. The experimental results presented here indicated that melatonin could be considered as an effective component of antioxidant treatment of preeclampsia, allowing the use of reduced doses of vitamin C and E owing to elevated efficiency of their antioxidant activity in placenta when used in combination.

[Pathomechanism of vitamin D intoxication]. / Patomechanizm zatrucia witamina D.

Pathomechanism of vitamin D intoxication is still unclear. Experiments on animals showed that intoxication is accompanied by distinctly elevated serum level of vitamin D precursor [25(OH)D3] but not by that of hormonally, metabolic active form of it [1alpha,25(OH)2D3]. The most probable explanation of this phenomenon is that vitamin D precursor releases hormonal form of vitamin from its binding with serum transporting protein (DBP) stimulating in this way transcription of genes in cells of target tissues.

[Significant periodical fluctuation of insulin requirement in patients with type 2 diabetes]. / Znaczne okresowe wahania zapotrzebowania na insuline u chorych na cukrzyce typu 2.

We have described three physicians aged 65-70 years, who had noticed during their insulintherapy significant, periodically recurrent variations of insulin requirement (max. 50 i.u./24h vs 25 i.u./24h) in the periods of 4-16 weeks. They had been characterized by similar diet and physical activity, stable normal body mass (av. BMI 24.6) and normal glycosylated hemoglobin (av. HbA1c 5.9%). The hypothesis was put forward that the cause of this phenomenon may be periodical changes in the incretin system activity or increased proliferation of pancreatic beta cells leading to decrease of insulin requirement.

[Weak anti-inflammatory effects of acetaminophen are related with its free radicals scavenger activity]. / Slabe wlasciwosci przeciwzapalne acetaminofenu wynikaja z jego dzialania jako zmiatacza wolnych rodników.

The main target of acetaminophen application is bifunctional enzyme--prostaglandin endoperoxide H2 synthase (PGHS)--which has cyclo-oxygenase and peroxidase activities and synthesizes initial intermediates in prostanoid synthesis. The reaction catalyzed by PGHS is radical-based and it is initiated and then maintained by the constant presence of peroxides especially peroxynitrate, which generate so-called "peroxide tone" in the enzyme surrounding. Currently it is known that inhibitory effect of acetaminophen on PGHS activity is directly connected with the elimination of "peroxide tone". High concentrations of reactive compounds (e.g. peroxynitrate and lipid peroxides)--produced by cellular defending mechanism at inflammatory sites--significantly decrease inhibitory impact of acetaminophen on PGHS activity. Such observation allows explanation of weak antiinflammatory effect of acetaminophen together with its strong analgesic and antipyretic properties.

[Hypercholesterolaemia among patients of the cardiology ward of a Regional Hospital in Wejherowo]. / Hipercholesterolemia wsród pacjentów oddzialu i Przychodni Kardiologicznej Szpitala Specjalistycznego w Wejherowie.

The strong positive relationship between cholesterolaemia and ischaemic heart disease is unquestioned and comes from several lines of evidence. In this paper results of questionnaire studies concerning cholesterolemia performed among patients of the Cardiology Ward of a Regional Hospital in Wejherowo are presented.

[Energy metabolism in the failing heart]. / Metabolizm energetyczny niewydolnego serca.

Daily heart consumption of energy (about 6 kg of ATP) exceeds significantly energy consumption of other organs. Deprivation of energy is considered as one of the main factors in development of heart failure. Currently available research methods permit not only to evaluate more precisely the role of impaired energy metabolism in the heart failure, but also give a hope for the future metabolic therapy.

NADPH- and iron-dependent lipid peroxidation inhibit aromatase activity in human placental microsomes.

During pregnancy placenta is the most significant source of lipid hydroperoxides and other reactive oxygen species (ROS). The increased production of lipid peroxides and other ROS is often linked to pre-eclampsia. It is already proved that placental endoplasmic reticulum may be an important place of lipid peroxides and superoxide radical production. In the present study we revealed that NADPH- and iron-dependent lipid peroxidation in human placental microsomes (HPM) inhibit placental aromatase--a key enzyme of estrogen biosynthesis in human placenta. We showed that significant inhibition of this enzyme is caused by small lipid peroxidation (TBARS (thiobarbituric acid-reactive substances)<4nmol/mg microsomal protein (m.p.)). More intensive lipid peroxidation (TBARS>9nmol/mg microsomal protein) diminishes aromatase activity to value being less than 5% of initial value. NADPH- and iron-dependent lipid peroxidation also causes disappearance of cytochrome P450 parallel to observed aromatase activity inhibition. EDTA, alpha-tocopherol, MgCl(2) and superoxide dismutase (SOD) prevent aromatase activity inhibition and cytochrome P450(AROM) degradation. Mannitol and catalase have not effect on TBARS synthesis, aromatase activity and cytochrome P450 degradation. In view of the above we postulate that the inhibition of aromatase activity observed is mainly a consequence of cytochrome P450(AROM) degradation induced by lipid radicals. The role of hydroxyl radical in cytochrome P450 degradation is negligible in our experimental conditions. The results presented here also suggest that the inhibition of aromatase activity can also take place in placenta at in vivo conditions.

Expression patterns of AMP-deaminase and cytosolic 5'-nucleotidase genes in human term placenta.

Background AMP-deaminase (EC 3.5.4.6) and 5'-nucleotidase (EC 3.1.3.5) are enzymes responsible for the maintenance of cellular adenine nucleotides pool. Both exist in several isoforms that differ in kinetic properties and tissue distribution. Profile of isoforms of these enzymes in human placenta has not been analyzed so far while this could be important for understanding of pathology of placental ischemia such as in preeclampsia. Our aim was therefore to analyze expression of AMPD and CN-I genes in human term placenta. Methods RT-PCR analysis was used for determine expression of AMPD1, AMPD2, AMPD3 and CN-I. Results and conclusion The experimental results presented here indicate that genes coding "AMP-preferring", cytosolic isozyme of 5'-nucleotidase (cN-I) as well as "muscle-type" isozyme of AMP-deaminase (AMPD1) are not expressed in human term placenta. Among other AMPD family genes, only these coding "liver-type" isozyme (AMPD2) and, in lesser degree, "erythrocyte-type" isozyme (AMPD3) of AMP-deaminase are expressed in this organ. The expression level of AMPD3 was a half of that presented by AMPD2. We conclude that high abundance of AMP-deaminase 2 transcript suggest that this particular isoform is a predominant pathway of adenine nucleotides degradation in human term placenta that follows liver-type regulation of this process.

[The role of intestine in detoxification]. / Rola jelita w detoksykacji.

In the result of liver detoxification, xenobiotics change into more water soluble and thus easier for excretion from the body. It is convenient to consider this process as occurring in two phases. In phase I, the major reactions involved are hydroxylation, catalyzed by monoxygenases. In phase II, the preliminary modified xenobiotics after conjugation with some specific metabolites are transformed into less toxic and more soluble end-products. Recently, antiporter activity of MDR1 (MultiDrug Resistence) gene products in enterocytes was recognized as important stage in detoxification of xenobiotics, and definied as phase III of this process.