Discovery of endogenous nitroxyl as a new redox player in Arabidopsis thaliana.

Nitroxyl (HNO) is the one-electron reduced and protonated congener of nitric oxide (•NO), owning a distinct chemical profile. Based on real-time detection, we demonstrate that HNO is endogenously formed in Arabidopsis. Senescence and hypoxia induce shifts in the redox balance, triggering HNO decay or formation mediated by non-enzymatic •NO/HNO interconversion with cellular reductants. The stimuli-dependent HNO generation supports or competes with •NO signalling, depending on the local redox environment.

Decreased bone mineral density and alteration in biochemical bone metabolism markers in children affected by bone tumors after completion of therapy.

UNLABELLED: The aim of this study was to assess bone mineral density (BMD) and biochemical bone metabolism markers in patients with bone tumors after anti-cancer treatment. The study included 27 patients (median age 15 years) with malignant bone tumors and 27 healthy children. In all subjects, BMD and body composition were measured by dual-energy x-ray absorptiometry. Serum bone markers were determined by immunoenzymatic assays. After completion of treatment, patients with bone tumors had significantly decreased total and lumbar spine BMD. We observed lower calcium and vitamin D levels in patients and comparable values of bone turnover markers (carboxyterminal telopeptide of collagen type I - CTX, bone alkaline phosphatase - BALP and osteocalcin - OC) in both groups of children. However, the level of carboxylated osteocalcin (cOC) was significantly lower (p<0.01) and undercarboxylated OC (ucOC) was higher (p<0.05) in patients than in controls. Additionally, we observed similar values of anthropometric parameters in the subgroups of patients treated with methotrexate (MTX) or without MTX. In patients treated without MTX we found lower (p<0.05) ratio of cOC/ucOC, lower vitamin D level and higher CTX concentrations. Patients with bone tumors after anticancer treatment had decreased bone mineral density and alterations in bone metabolism markers with potential decrease in bone formation. KEYWORDS: bone cancer survivors, bone mineral density, bone formation markers, bone resorption markers, methotrexate.

Bone turnover markers, osteoprotegerin and RANKL cytokines in children with cystic fibrosis.

PURPOSE: Some scientific studies show decreased bone mineral density and increased fracture frequency in adult patients with cystic fibrosis (CF). The mechanism for early bone loss in CF patients are multifactorial: chronic pulmonary inflammation, malnutrition, reduced physical activity, delayed pubertal maturation. The aim of this study was to assess bone metabolism markers with special attention paid to osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) balance in CF children. MATERIAL AND METHODS: The study included 35 children with diagnosed CF and 35 healthy controls aged 5-9 years (median 7.0 years). Serum levels of fat soluble vitamins were measured by chemiluminescence (vitamin D) and HPLC (vitamins A, E) methods. Concentrations of bone metabolism markers were determined by immunoenzymatic assay. RESULTS: Mean levels of fat soluble vitamins (A, D, E) were lower in patients with CF compared to controls. In CF children we observed a significant (p<0.01) decrease in concentration of bone formation marker (osteocalcin) and similar bone resorption markers (CTX, TRACP5b) in comparison with healthy children. The serum level of OPG was significantly lower (p<0.05) and RANKL nearly 2-fold higher in patients with CF than in the healthy ones. The ratio of OPG to RANKL was about 2-fold lower in children with CF compared to healthy peers (p<0.01). CONCLUSION: In CF children, an imbalance between bone formation and resorption processes occurs. An increase serum RANKL concentration coexisting with lower levels of OPG may be associated with intensification of bone resorption.

Alterations in markers of bone metabolism and adipokines following a 3-month lifestyle intervention induced weight loss in obese prepubertal children.

BACKGROUND: Adipokines may influence bone metabolism in children, but this phenomenon is not well understood. Therefore, we studied the relationships between bone markers and adipokines during weight loss in obese children. MATERIALS AND METHODS: We determined serum leptin, soluble leptin receptor (sOB-R), adiponectin, BALP (bone alkaline phosphatase), CTX-I (C-terminal telopeptide of type I collagen), body composition and bone mineral density (by dual-energy X-ray absorptiometry) in 100 obese prepubertal children before and after 3 months of lifestyle intervention (low-energy diet, physical activity). The control group consisted of 70 non-obese children. RESULTS: Obese children had higher BALP activity by about 20% (p<0.001) and similar value of CTX-I compared with non-obese children. After weight loss (-0.96 BMI-SDS mean change), the BALP value in obese patients decreased (p<0.001), whereas CTX-I concentration was unchanged. Changes in BALP were positively correlated with changes in BMI (Body Mass Index) (r=0.352, p<0.001), but not associated with adipokine levels. Trend analysis using SDS-BMI subgroups showed that greater reduction of body mass was associated with a greater decrease of BALP (p=0.035) and leptin values (p<0.001), as well as a greater increase of sOB-R (p<0.003). CONCLUSIONS: Obesity during the prepubertal period is associated with an alteration in the adipokines profile and greater whole-body bone mass as a result of increased bone formation rather than reduced bone resorption. Changes in bone metabolism during lifestyle intervention seem to be related to weight loss but not to changes in adipokines. Further studies should elucidate the influence of long-term therapy on bone mass in childhood.

Clinical utility of biochemical bone turnover markers in children and adolescents with osteosarcoma.

PURPOSE: Biochemical markers of bone turnover reflecting the intensity of all bone remodeling processes in skeleton are important for fast and non-invasive assessment of bone formation and resorption processes. They can be used in terms of both physiological and pathological states. The aim of this study was to investigate if bone metabolism markers can be clinically useful for monitoring of treatment in children and adolescents with osteosarcoma. MATERIAL/METHODS: The study consisted of 55 patients (median age 15 years) with osteosarcoma and 60 healthy age matched counterparts. Serum bone turnover markers (bone alkaline phosphatase - BALP, osteocalcin - OC and C-terminal telopeptide of type I collagen - CTX) were analyzed by immunoenzymatic methods in patients at time of diagnosis, during treatment and after therapy. RESULTS: We observed that before treatment the concentration of OC in patients with osteosarcoma was significantly lower (p<0.05) compared to that obtained in healthy children, however, BALP and CTX were at a similar level. During chemotherapy the values of bone formation and resorption markers significantly decreased by about 20-30%. After therapy we observed different concentrations of all bone turnover markers in patients with favorable and unfavorable prognosis. Median values of OC and BALP were over twofold higher in patients with progression as compared to patients with remission of disease (p<0.01 and p<0.001, respectively). Patients with poor prognosis had also higher serum concentration of bone resorption marker in comparison to patients with remission (p<0.01). CONCLUSIONS: Presented results suggest that bone turnover markers identify changes in bone metabolism in patients with osteosarcoma during anticancer therapy. These markers due to the non-invasive methods and their specificity might be useful in monitoring of clinical treatment of osteosarcoma patients.

Serum markers of bone turnover in children and adolescents with classic galactosemia.

PURPOSE: Classic galactosemia is an inherited metabolic disease resulting from galactose-1-phosphate uridyltransferase (GALT) deficiency. Dietary lactose exclusion reverses many clinical manifestations of acute phase of the disease. Unfortunately most of the patients, despite dietary treatment, develop long-term complications among them disturbances of bone mineralization resulting in decrease of bone mineral density (BMD). The aim of our study was to assess bone formation and resorption processes with bone turnover markers in children and adolescents with galactosemia. MATERIALS AND METHODS: We studied 62 galactosemic children (mean age+/-SD 5.9+/-2.7 years) and adolescents (mean age+/-SD 15.6+/-2,4 years). The clinical diagnosis had been confirmed by the absence of GALT activity in erythrocytes. All patients were diagnosed in the neonatal period and had good dietary control. Healthy children (n=70) were the reference group. Serum osteocalcin (OC), bone alkaline phosphatase (BALP), collagen type I crosslinked C-telopeptide (CTX-I), 25(OH)D metabolite of vitamin D were determined by ELISA assays. RESULTS: We observed similar mean values of bone formation markers in children with galactosemia as compared to the age-matched controls. The level of bone resorption marker CTX-I in these patients was lower by about 20% (p<0.001) than in healthy children. On the contrary we obtained slightly higher values of CTX-I in adolescents with galactosemia in comparison to the age-matched controls. In these patients the values of OC and BALP were significantly higher than in healthy adolescents (111.8+/-52.1 microg/L versus 82.3+/-43.0 microg/L, p<0.02; and 95.4+/-45.7 U/L versus 72.6+/-40.6 U/L, p<0.05 respectively). CONCLUSION: Our results suggest that bone turnover in galactosemic patients elevates from childhood to adolescence, whereas in healthy individuals there is a decline during aging. Further studies on adults with galactosemia are necessary to assess bone status in these patients.

Serum concentration of biochemical bone turnover markers in vegetarian children.

PURPOSE: In general, most children on well-planed vegetarian diets can achieve normal growth and development. However, elimination of animal products from the diet decreases the intake of some essential nutrients, such as calcium and vitamin D, and may influence bone metabolism. This is especially important in childhood and adolescence, when growth and bone turnover are most intensive. The aim of this study was to investigate the serum concentrations of biochemical bone turnover markers in prepubertal vegetarian children. MATERIAL AND METHODS: We examined 50 children on vegetarian and 50 on omnivorous diets aged 2-10 years. Dietary constituents were analyzed using a local nutritional program. Serum bone formation (OC, BALP) and resorption (CTX) markers were determined by specific enzyme immunoassays (ELISA) and 25-hydroxyvitamin D by the chemiluminescence method (CLIA). RESULTS: The average daily energetic value and the percentage of energy from protein, fat and carbohydrates in the diets were similar in both groups of children and were within the recommended range. The vegetarian children showed about a two-fold lower daily intake of calcium and vitamin D than their omnivorous counterparts. The level of 25-hydroxyvitamin D in the serum of vegetarian children was also nearly 2-fold lower compared with omnivores. In vegetarians, as compared to non-vegetarians, mean serum concentrations of OC, BALP and CTX were lower by about 20%, 10% and 15%, respectively. CONCLUSION: Our preliminary results suggest that an inadequate dietary intake of calcium and vitamin D may impair bone turnover rate in vegetarian children. The parameters of bone metabolism should be monitored in these children in order to prevent bone abnormalities.

Serum homocysteine, folate, vitamin B12 and total antioxidant status in vegetarian children.

PURPOSE: The results of several studies point to the positive role of vegetarian diets in reducing the risk of diabetes, some cancers and cardiovascular diseases. However, exclusion of animal products in vegetarian diets may affect the cobalamin status and cause an elevation of the plasma homocysteine level. The aim of this study was to assess the effect of vegetarian diets on serum concentrations of homocysteine, folate, vitamin B12 and total antioxidant status (TAS) in children. MATERIAL AND METHODS: The study included 32 vegetarians (including 5 vegans), age 2-10 years. Dietary constituents were analyzed using a local nutritional programme. Serum homocysteine, folate and vitamin B12 were determined with fluorescence and chemiluminescence immunoassays. The concentration of TAS was measured by a colorimetric method. RESULTS: Average daily energy intake and the percentage of energy from protein, fat and carbohydrates in the diets of the studied children were just above or similar to the recommended amounts. It could be shown that vegetarian diets contain high concentrations of folate. In vegan diets it even exceeds the recommended dietary allowance. Mean daily intake of vitamin B12 in the studied diets was adequate but in vegans was below the recommended range. The serum concentrations of homocysteine, folate, vitamin B12 and TAS in vegetarian children remained within the physiological range. CONCLUSIONS: The presented data indicate that vegetarian children, contrary to adults, have enough vitamin B12 in their diet (excluding vegans) and normal serum concentrations of homocysteine, folate and vitamin B12. Therefore, in order to prevent deficiencies in the future, close monitoring of vegetarian children (especially on a vegan diet) is important to make sure that they receive adequate quantities of nutrients needed for healthy growth.

Osteoprotegerin and C-telopeptide of type I collagen in Polish healthy children and adolescents.

PURPOSE: Most metabolic bone diseases are characterized by a disturbances in bone resorption, therefore biochemical markers concerning this process are of special interest. Recently, the novel cytokine osteoprotegerin (OPG), belonging to the tumor necrosis factor receptor family has been established as an endogenous inhibitor of osteoclastogenesis and resorption process. In addition serum C-telopeptide of type I collagen (s-CTX) is one of the resorption markers released into circulation as a result of the osteoclast mediated degradation of type I collagen. However, a clinical application of OPG and s-CTX in children may be difficult by less information of suitable reference data in relation to age, race and sex. The aim of our study was to invastigate serum concentrations of both markers in polish healthy children and adolescents. MATERIAL AND METHODS: We examined 102 healthy children and adolescents in 6-24 years of age, divided on prepubertal, pubertal and postpubertal groups. OPG and s-CTX were determined by ELISA kits from Biomedica (Austria) and Osteometer (Denmark) respectively. RESULTS: The highest mean values of OPG were in prepubertal girls (4.64 +/- 0.57 pmol/L) and boys (4.28 +/- 0.86 pmol/L). Next, in older children and adolescents gradually decreased of OPG concentration was observed. We also obtained the decreased of s-CTX concentration in studied children except these in pubertal period. Generally, we obtained significant positive correlation between OPG and s-CTX in all observed groups (n = 102, r = 0.653; p < 0.0001). CONCLUSIONS: We report the age-related decrease in circulating endogenous OPG during childhood and adolescence. Serum OPG concentration in postpubertal period may be similar to those presented in young adults. Prospective studies are needed to investigate the influence of OPG on bone metabolism in children.

[Selected independent risk factors of atherosclerosis in children as the basis of early detection of premature ischemic heart disease]. / Wybrane niezalezne czynniki ryzyka miazdzycy u dzieci jako podstawa wczesnego wykrywania zagrozenia choroba niedokrwienna serca.

This review briefly summarises the scientific evidence for the child's future risk of ischemic heart diseases (IHD). The conventional risk factors such as dyslipidemia, hypertension, diabetes and smoking can not account for all the cases of cardiovascular diseases. Therefore other risk factors such as fibrinogen, homocysteine, paraoxonaze and abnormality in antioxidant defence systems are included. Among the lipids parameters the level of lipoprotein (a) and increased plasma cholesterol, specifically LDL-cholesterol may be used as a marker of family history of IHD and hypercholesterolemia. Additionally, low level of HDL-cholesterol is also related with endothelial dysfunction and increased oxidative stress. It has been hypothesised that free radicals mediate in the development of IHD and that antioxidants play a protective role in prevention of this pathology. Many of the major risk factors can be modified through diet, body mass control, exercise and (if necessary) through pharmacological intervention. Therefore, the efficacious prevention should be related with the early detection of risk factors particularly in children with familial dyslipidemia, hypertension and IHD.

[Selected parameters of antioxidant capacity in renal allograft recipients]. / Wybrane wskazniki systemu przeciwutleniajacego u biorców allogennej nerki.

UNLABELLED: Various oxidant species, oxygen free radicals (OFR) implicated in patients with chronic renal diseases treated with dialysis and after cadaveric renal transplantation. Oxidative stress occurs when free radical generation exceeds antioxidant defence. We therefore examined markers of lipid peroxidation and antioxidant potential in blood (serum, plasma, RBC) of very carefully (clinically and biochemically) selected 102 subjects (56 female and 46 male, mean age 37.5 +/- 7 years). Included were 51 renal allograft recipients (RARs); 15 patients with glomerulopathies (GL); 36 healthy age- and sex-matched volunteers as a control group (C). All RARs were divided into two subgroups: RARs-A (n = 28) were treated with triple drug therapy including cyclosporin A (CsA) and RARs-Z (n = 23) were on double drug regimen: prednisone, azathioprine. Patients with coronary artery disease (CAD), diabetes, serum creatinine concentration > 2.0 mg/dl, acute rejection and infections were excluded. We used several automated assays to estimate: malondialdehyde (MDA); total radical-trapping antioxidant potential (TRAP), glutathione peroxidase (GPx), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), vit. E and lipid profiles. Patients of RARs-A were found to have significantly elevated triglycerides; cholesterol-LDL; MDA; TRAP and decreased activity of RBC glutathione peroxidase as compared with those of RARs-Z and group C. IN CONCLUSION: our data show that oxidative stress (with prooxidant effect of CsA partly at least), with reduced in antioxidant potential of defences system is associated with kidney transplantation.

[Biochemical markers of bone turnover and their use]. / Biochemiczne markery obrotu kostnego i ich zastosowanie.

Although the clinician's ability to diagnose and monitor bone disease has improved in the past decade, there is still a need for more specific methods of assessing disturbances in bone metabolism. This article presents a review of biochemical bone markers and their practical applications in various disease states. Bone resorption and formation markers are considered to be useful in diagnosis and anticancer treatment of primary osseous tumours and metastatic bone diseases. However, better understanding of cellular and molecular events in the different phases of remodeling seems to be necessary to develop more adequate clinical diagnostic procedures and treatment for bone diseases.

Antioxidant defence of red blood cells and plasma in stored human blood.

Blood collected routinely from donors, and preserved with CPDA-1 anticoagulant (citrate, phosphate, dextrose, adenine), was investigated. The concentration of reduced glutathione, and glutathione peroxidase, glutathione S-transferase, glutathione reductase, superoxide dismutase, and catalase activities in erythrocytes, as well as the total radical-trapping antioxidant parameter in plasma were determined on days 1, 3, 7, 12, 16, 20 and 25 of storage. At the end of the study, a 30% decrease in the reduced glutathione concentration (P < 0.001) and decreases in glutathione S-transferase (over 20%, P < 0.001), glutathione reductase (over 8%, P < 0.01) and superoxide dismutase (over 10%, P < 0.001) activities in erythrocytes, together with up to a 30% diminution of total antioxidant activity in plasma (P < 0.001) were noted. Thus, during blood storage, glutathione-dependent antioxidant systems in erythrocytes and antioxidant defence in plasma are depleted. From the present study, a twelve-day period can be considered a safe storage limit. The sequence of events occurring in stored blood, leading to peroxidative injury in erythrocytes, is discussed.

Antioxidant and glutathione-associated enzymes in Wilms' tumour after chemotherapy.

The present study demonstrates the activities of antioxidant and glutathione-associated enzymes and the level of glutathione in Wilms' tumour (nephroblastoma) samples after chemotherapy (mainly actinomycin D and vincristine). We observed higher activity of superoxide dismutase in Wilms' tumour compared to adjacent morphologically unchanged kidney. On the other hand, in this tumour lower activities of catalase and the glutathione-associated enzymes glutathione synthetase, gamma-glutamyl transpeptidase, glutathione reductase and total glutathione S-transferases (GST) were found. Using isoelectric focusing we separated different forms of GST in tested tissues and revealed lower activities of the basic enzymes in Wilms' tumour, which may be responsible for the decrease of total GST activity. Moreover, we found the acidic isoenzymes to be the predominant class of GST in nephroblastoma. In Wilms' tumours with unfavourable histology a high activity of these isoenzymes together with a high level of GSH were observed. We suggest that these parameters may participate in the known phenomenon of anticancer drug resistance of tumours with unfavourable histology.

[Blood antioxidant defense in children with malignant disease. I. Plasma antioxidant activity and level of ceruloplasmin and transferrin]. / Obrona przeciwutleniajaca we krwi dzieci z choroba nowotworowa. Czesc I. Aktywnosc przeciwutleniajaca osocza oraz stezenie ceruloplazminy i transferyny.

In this study we examined selected elements of the antioxidant defence system in the plasma of children with the most common solid tumors (nephroblastoma, neuroblastoma, rhabdomyosarcoma, osteosarcoma). We observed a significant increase of plasma antioxidant activity (AOA) in the majority of the examined children. This factor changed during clinical treatment, i.e. induction of chemotherapy, surgery and/or radiotherapy and during maintenance chemotherapy. We conclude that the elevated plasma antioxidant activity in children with malignancy may be due to the higher concentration of ceruloplasmin in affected children than in their healthy counterparts.

[Defense system antioxidants in blood of children with neoplasms. II. Antioxidant enzymes and lipid peroxidation in erythrocytes]. / Obrona przeciwutleniajaca we krwi dzieci z choroba nowotworowa. Czesc II. Enzymy przeciwutleniajace oraz peroksydacja lipidów w krwinkach czerwonych.

The aim of the work was to investigate selected parameters of antioxidant defence in red blood cells of children suffering from various types of solid tumors. In patients with these tumors, glutathione reductase and glutathione S-transferase activities were found to be reduced in comparison to healthy children.

[Agranulocytosis in the course of clozapine treatment]. / Agranulocytoza w trakcie stosowania klozapiny.

Clozapine is highly effective for drug resistant schizophrenia, it does not cause any extrapiramidal side effects, but involves a high risk of agranulocytosis with fatal outcome. The pathogenesis of agranulocytosis is not clear but genetic factors, as well as immunological and toxic mechanism may play an important role. Since the introduction of the monitoring system of leucocytosis for every patient an increasing number of agranulocytosis cases are being registered. Owing to the monitoring system, an immediate discontinuation of the drug, and the initiation of appropriate treatment the number of cases with fatal outcome is not growing in spite of the increasing number of patients treated with clozapine. In the described patient with chronic schizophrenia and ulcerative disease, agranulocytosis disappeared within 7 days after discontinuation of the drug. Three months later the patient died because of perforation of a duodenal ulcer. A negative influence of closapine on ulcerative disease should by considered, but the authors have not found any information on this topic in the literature.

Glutathione S-transferase isoenzymes and glutathione in renal cell carcinoma and kidney tissue.

Many studies have established the role of the glutathione S-transferases (GSTs) and glutathione (GSH) in the neoplastic process and the drug resistance of tumor. Using isoelectric focusing we separated different forms of GSTs in 28 renal cell carcinomas (RCCs) and in morphologically unchanged adjacent kidney. In addition we determined in RCCs and adjacent kidney the level of GSH and the activities of enzymes participating in synthesis and uptake of this thiol compound. We found higher activity of acidic GSTs and higher level of GSH in RCCs versus kidney. Therefore we suggest that both parameters may play the significant role in the well known phenomenon of intrinsic cytostatic drug resistance of RCC. We also observed the elevation of GSH synthetase activity in tumor tissues in comparison to the kidneys. It may indicate that GSH synthetase, catalysing the final step in GSH synthesis, may participate in the elevation of GSH concentration in RCCs. In this work we also compared the tested parameters in RCCs in relation to the size and local extent of primary tumor (T). We found significantly lower activity of gamma-glutamyl transpeptidase (GGT) as well as GSH synthetase in the group of T3 and T4 tumors than in T2 tumors. However, no substantial differences in GSH concentrations were observed between these distinguished groups.