Characterization of the Key Bibenzyl Synthase in Dendrobium sinense

Dendrobium sinense, an endemic medicinal herb in Hainan Island, is rich in bibenzyls. However, the key rate-limited enzyme involved in bibenzyl biosynthesis has yet to be identified in D. sinense. In this study, to explore whether there is a significant difference between the D. sinense tissues, the total contents of bibenzyls were determined in roots, pseudobulbs, and leaves. The results indicated that roots had higher bibenzyl content than pseudobulbs and leaves. Subsequently, transcriptomic sequencings were conducted to excavate the genes encoding type III polyketide synthase (PKS). A total of six D. sinense PKS (DsPKS) genes were identified according to gene function annotation. Phylogenetic analysis classified the type III DsPKS genes into three groups. Importantly, the c93636.graph_c0 was clustered into bibenzyl synthase (BBS) group, named as D. sinense BBS (DsBBS). The expression analysis by FPKM and RT-qPCR indicated that DsBBS showed the highest expression levels in roots, displaying a positive correlation with bibenzyl contents in different tissues. Thus, the recombinant DsBBS-HisTag protein was constructed and expressed to study its catalytic activity. The molecular weight of the recombinant protein was verified to be approximately 45 kDa. Enzyme activity analysis indicated that the recombinant DsBBS-HisTag protein could use 4-coumaryol-CoA and malonyl-CoA as substrates for resveratrol production in vitro. The Vmax of the recombinant protein for the resveratrol production was 0.88 ± 0.07 pmol s⁻¹ mg⁻¹. These results improve our understanding with respect to the process of bibenzyl biosynthesis in D. sinense.

Nitric Oxide Synthase inhibition counteracts the stress-induced DNA methyltransferase 3b expression in the hippocampus of rats

It has been postulated that the activation of NMDA receptors (NMDAr) and nitric oxide (NO) production in the hippocampus is involved in the behavioral consequences of stress. Stress triggers NMDAr-induced calcium influx in limbic areas, such as the hippocampus, which in turn activates neuronal NO synthase (nNOS). Inhibition of nNOS or NMDAr activity can prevent stress-induced effects in animal models, but the molecular mechanisms behind this effect are still unclear. In this study, cultured hippocampal neurons treated with NMDA or dexamethasone showed an increased of DNA methyltransferase 3b (DNMT3b) mRNA expression, which was blocked by pre-treatment with nNOS inhibitor nω -propyl-l-arginine (NPA). In rats submitted to the Learned Helplessness paradigm (LH), we observed that inescapable stress increased DNMT3b mRNA expression at 1h and 24h in the hippocampus. The NOS inhibitors 7-NI and aminoguanidine (AMG) decreased the number of escape failures in LH and counteracted the changes in hippocampal DNMT3b mRNA induced in this behavioral paradigm. Altogether, our data suggest that NO produced in response to NMDAr activation following stress upregulates DNMT3b in the hippocampus.

Proteomic Profiling and Pathway Analysis of Acid Stress-Induced Vasorelaxation of Mesenteric Arteries In Vitro

Although metabolic acidosis is associated with numerous pathophysiological conditions and its vasorelaxation effects have been well described in different animal and culture models, the molecular mechanisms of acidosis-induced vasorelaxation are not fully understood. Mesenteric artery models have been used extensively to examine the vascular response to various pathophysiological conditions. Our previous studies and several other reports have suggested the vascular responses of goat mesenteric arteries and human arteries to various stimuli, including acidic stress, are highly similar. In this study, to further identify the signaling molecules responsible for altered vasoreactivity in response to acidic pH, we examined the proteomic profile of acid stress-induced vasorelaxation using a goat mesenteric artery model. The vascular proteomes under acidic pH were compared using 2D-GE with 7 cm IPG strips and mini gels, LC-MS/MS, and MALDI TOF MS. The unique proteins identified by mass spectroscopy were actin, transgelin, WD repeat-containing protein 1, desmin, tropomyosin, ATP synthase β, Hsp27, aldehyde dehydrogenase, pyruvate kinase, and vitamin K epoxide reductase complex subunit 1-like protein. Out of five protein spots identified as actin, three were upregulated > 2-fold. ATP synthase β was also upregulated (2.14-fold) under acid stress. Other actin-associated proteins upregulated were transgelin, desmin, and WD repeat-containing protein 1. Isometric contraction studies revealed that both receptor-mediated (histamine) and non-receptor-mediated (KCl) vasocontraction were attenuated, whereas acetylcholine-induced vasorelaxation was augmented under acidosis. Overall, the altered vasoreactivity under acidosis observed in the functional studies could possibly be attributed to the increase in expression of actin and ATP synthase β.

NO source in higher plants: present and future of an unresolved question

Nitric oxide (NO), a signaling free radical, is directly or indirectly involved in virtually all plant physiological processes. Although the enzymatic NO source L-arginine (L-Arg)-dependent nitric oxide synthase (NOS) has been well characterized in animal systems, how NO is enzymatically generated in higher plants remains a subject of debate.

Nitric Oxide Synthase activity in major depressive episodes before and after antidepressant treatment: Results of a large case-control treatment study

BACKGROUND

Nitric oxide synthase (NOS) activity, an enzyme potentially involved in the major depressive episodes (MDE), could be indirectly measured by the L-Citrulline/L-Arginine ratio (L-Cit/L-Arg). The aim of this study was: (1) to compare the NOS activity of patients with a MDE to that of healthy controls (HC); (2) to assess its change after antidepressant treatment.

METHODS

A total of 460 patients with a current MDE in a context of major depressive disorder (MDD) were compared to 895 HC for NOS activity (L-Cit/L-Arg plasma ratio). L-Arg and L-Cit plasma levels were measured using a MS-based liquid chromatography method. Depressed patients were assessed at baseline, and after 3 and 6 months of antidepressant treatment for depression severity and clinical response.

RESULTS

Depressed patients had a lower NOS activity than HC at baseline [0.31 ± 0.09 v. 0.38 ± 0.12; 95% confidence interval (CI) -0.084 to -0.062, p < 0.0001]. Lower NOS activity at baseline predicted a higher response rate [odds ratio (OR) = 29.20; 95% CI 1.58-536.37; p = 0.023]. NOS activity in depressed patients increased significantly up to 0.34 ± 0.08 after antidepressant treatment (Est = 0.0034; 95% CI 0.0002-0.0067; p = 0.03).

CONCLUSIONS

Depressed patients have a decreased NOS activity that improves after antidepressant treatment and predicts drug response. NOS activity may be a promising biomarker for MDE in a context of MDD.

[Effects of 12-week Tai Chi exercise on the microvascular reactivity of the middle-aged and elderly patients with mild hypertension and its mechanism]

Objective: To study the effects of 12-week Taijiquan exercise on the microvascular reactivity of middle-aged and elderly patients with mild hypertension and to explore the mechanisms of microvascular reactivity. Methods: Thirty patients with mild hypertension were divided into exercise group (53.8±6.3 years old) and control group (52.6±7.5 years old). The number and gender ratio of the two groups were the same. The exercise group performed Tai Chi exercise for 12 weeks, and the control group maintained the original lifestyle and did not do other regular sports. The two groups of subjects were tested for microvascular reactivity, blood pressure, serum nitric oxide content, and nitric oxide synthase activity before exercise intervention, 6th week and 12th week, respectively. Results: There was no significant difference in the basic values of each index between the two groups of subjects before the test (P＞ 0.05). In the 6th week, the microvascular reactivity (blood flow increase rate), systolic blood pressure, diastolic blood pressure, nitric oxide content, nitric oxide synthase activity of the exercise group did not significantly change from the basic value (P＞0.05). At the 12th week, the microvascular reactivity, nitric oxide content, c nitric oxide synthase activity were significantly higher than those of the base values and the control group (P＜0.05), but the systolic blood pressure and diastolic blood pressure were significantly lower than those of the base values and control group (P＜0.05). In the control group, there were no significant changes in the 6th and 12th week values of each index from the basic value (P＞0.05). Conclusion: Twelve weeks of Taijiquan exercise can improve the microvascular reactivity of middle-aged hypertensive patients, reduce blood pressure, and increase the nitric oxide content and c nitric oxide synthase of patients. The increase of endogenous nitric oxide production is one of the biological mechanisms of Tai Chi exercise to improve the microvascular responsiveness of hypertension patients.

Nitric Oxide Mediation in Hydroxyurea and Nitric Oxide Metabolites' Inhibition of Erythroid Progenitor Growth

In several systems, hydroxyurea has been shown to trigger nitric oxide (NO) release or activation of NO synthase (NOS). To elucidate this duality in its pharmacological effects, during myelosuppression, we individually examined hydroxyurea's (NO releasing agent) and NO metabolites' (stable NO degradation products) effects on erythroid colony growth and NOS/NO levels in mice using NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO). Hydroxyurea and nitrite/nitrate decreased the bone marrow cellularity that was blocked by PTIO only for the NO metabolites. Hydroxyurea inhibition of colony-forming unit-erythroid (CFU-E) formation and reticulocytes was reversed by PTIO. Moreover, hydroxyurea, through a negative feedback mechanism, reduced inducible NOS (iNOS) expressing cells in CFU-E, also prevented by PTIO. Nitrate inhibition of burst-forming units-erythroid (BFU-E) colony growth was blocked by PTIO, but not in mature CFU-E. The presented results reveal that NO release and/or production mediates the hydroxyurea inhibition of mature erythroid colony growth and the frequency of iNOS immunoreactive CFU-E.

Effects of ozone treatment on penile erection capacity and nitric oxide synthase levels in diabetic rats

We aimed to determine the effects of ozone treatment on functional and biochemical changes in corpus cavernosum of diabetic rats. A total of 18 rats were included in the study. The rats were divided into the three groups as control, diabetes mellitus, and diabetes mellitus + ozone therapy groups. In the latter, ozone gas mixture was administered intraperitoneally for 2 weeks after the induction of experimental diabetes model. Erectile response was evaluated by determining mean intracavernosal pressure. Tissue neuronal, inducible and endothelial nitric oxide synthase levels were evaluated with commercial ELISA kits. Immunohistochemical evaluation was also performed to determine the expression levels of nitric oxide synthases semiquantatively. Mean intracavernosal pressure and intracavernosal pressure/systemic arterial blood pressure ratio were significantly higher in the diabetes mellitus + ozone therapy group than those of diabetes mellitus group (24.57 ± 6.36 mmHg vs. 5.98 ± 2.04 mmHg, p = 0.005 and 0.81 ± 0.16 vs. 0.26 ± 0.11, p = 0.0001, respectively). The level of penile tissue endothelial nitric oxide synthase was significantly higher in diabetes mellitus + ozone therapy group compared with others (19.28 ± 3.40 ng/mL vs. 13.47 ± 2.06 ng/mL and 13.28 ± 1.48 ng/mL, P = 0.01). Endothelial nitric oxide synthase expression increased significantly with ozone therapy. Our results suggest that ozone therapy may be beneficial in reducing the negative effects of diabetes on erectile dysfunction as a result of enhanced enzymatic activity in endothelial nitric oxide synthase levels.

NEUROCHEMICAL STATUS OF NITRIC OXIDE IN THE SETTINGS OF THE NORM, ISHEMIC EVENT OF CENTRAL NERVOUS SYSTEM, AND PHARMACOLOGICAL BN INTERVENTION

The purpose of the given research is to study the efficiency of different inhibitors of NO-synthase in conditions of experimental cerebral ischemia by their capability to limit reactions of oxidative and nitrosative stress. In the given study a non-selective NOS inhibitor - N-nitro-L-arginine; a highly selective inhibitor of neuronal NOS - N-propyl-L-arginine and a highly selective competitive inhibitor of inducible NOS - (S)-methylurea were used. Cerebral circulation impairment was simulated by means of double-sided occlusion of common carotid arteries. It has been established that neurotoxic NO effect depends on definite enzyme of NO-synthase. Analysis of the obtained data shows a limited role of neuronal isoform in conditions of experimental impairment of blood circulation. The most relevant target for pharmacological regulation of NO-dependent mechanisms of neurodestruction is iNOS because of the fact that its activity begins to increase 12 hours after ischemia development and its action is implemented during several following days.

Tetrahydrobiopterin and Nitric Oxide Synthase Recouplers

Generation of nitric oxide (NO) by the nitric oxide synthase (NOS) enzymes plays multiple signalling roles in every organ system, with crucial roles in the cardiovascular system, mediated by endothelial nitric oxide synthase (eNOS, encoded by NOS3) and neuronal nitric oxide synthase (nNOS, encoded by NOS1) in regulation of blood pressure, flow, oxygen delivery and cardiac function. Loss of normal NO-mediated functions in cardiovascular disease state is associated with changes in nitroso-redox signalling that are not dependent solely upon altered NO generation, but increased generation of reactive oxygen species (ROS). The NOS enzymes can also generate ROS, in a catalytic mode whereby the generation of NO from L-arginine is 'uncoupled' from the reduction of molecular oxygen. NOS uncoupling is determined by several factors, including the availability and oxidation state of the required NOS cofactor, tetrahydrobiopterin (BH4). The duality of NOS functions as enzymes that generate both NO and ROS under different regulatory states has emerged as an important pathophysiologic mechanism, and is a potential therapeutic target, via agents that can maintain or restore NOS coupling, for example via effects on BH4 availability.

Norepinephrine Regulation of Ventromedial Hypothalamic Nucleus Metabolic-Sensory Neuron 5'-AMP-Activated Protein Kinase Activity: Impact of Estradiol

The mediobasal hypothalamus (MBH) shapes the neural regulation of glucostasis by 5′-AMP-activated protein kinase (AMPK)-dependent mechanisms. Yet, the neurochemical identity and neuroanatomical distribution of MBH neurons that express glucoprivic-sensitive AMPK remain unclear. The neurotransmitters γ-aminobutyric acid (GABA) and nitric oxide (NO) act within the MBH to correspondingly inhibit or stimulate glucose counter-regulation. The current review highlights recent findings that GABA and NO, neurons located in the ventromedial hypothalamic nucleus (VMN), a distinct important element of the MBH, are direct targets of noradrenergic regulatory signaling, and thereby, likely operate under the control of hindbrain metabolic-sensory neurons. The ovarian hormone estradiol acts within the VMN to govern energy homeostasis. Discussed here is current evidence that estradiol regulates GABA and NO nerve cell receptivity to norepinephrine and moreover, controls the noradrenergic regulation of AMPK activity in each cell type. Future gains in insight on mechanisms underpinning estradiol’s impact on neurotransmitter communication between the hindbrain and hypothalamic AMPKergic neurons are expected to disclose viable new molecular targets for the therapeutic simulation of hormonal enhancement of neuro-metabolic stability during circumstances of diminished endogenous estrogen secretion or glucose dysregulation.

EXAMINING THE ROLE OF THE NITRIC OXID SYSTEM AS THE ESSENTIAL PATHOGENETIC LINK IN STEVENS-JOHNSON SYNDROME

OBJECTIVE

The aim: To determine a possible role of nitric oxide system as one of the pathogenesis links in Stevens-Johnson syndrome depending on the severity of disease progression.

PATIENTS AND METHODS

Material and methods: We examined 11 patients with Stevens-Johnson syndrome. The function of nitric oxide system (NO - NOS) in blood serum was examined.

RESULTS

Results: During the study of nitric oxide system (NO-NOS) in patients with SJS, it was observed that NO2¯ level was increased by 1.53 times, NO3¯ level - by 3.33 times, activity of total NOS - by 5.78 times, constitutive (cNOS) - by 1.81 times and inducible (iNOS) - by 13.36 times.

CONCLUSION

Conclusions: The intensity of nitric oxide system function was studied in patients with Stevens-Johnson syndrome and dependence of changes of its parameters from the clinical signs of disease was detected. It was found that the determination of nitrite and nitrate anion levels in blood serum can be used for the purpose of predicting the disease course and choosing the therapy methods for the patients with SJS.

[MIELIN BASIC PROTEIN IN THE BRAIN TISSUE OF THE BALB/C MICE WITH EXPERIMENTAL ANTIPHOSPHOLIPID SYNDROME AND AFFECTION WITH NITRIC OXIDE SYNTHESIS MODULATORS]

The aim of the research was to study the content of myelin basic protein (MBP) in the cerebellum and cerebral hemispheres of the BALB/c mice with experimental antiphospholipid syndrome as well as in cases of introduction of L-arginine and aminoguanidine. The research was performed using 50 female BALB/c mice, in which APS was simulated. L-arginine (25 mg/kg) and aminoguanidine (10 mg/kg) were used for correction. A Western blot analysis of the main myelin protein (antibodies against MBP) as well as a densitometric analysis of immunoreactive zones was carried out using the samples of the cerebellum and cerebral hemispheres of the control and experimental BALB/c mice. The increased content of MBP (18.4 kDa) in 256 times (p<0.001) in the tissue of the cerebral hemispheres of the BALB/c mice with antiphospholipid syndrome was evidenced compare to the control. It was found out that in the samples of the cerebral hemispheres, the content of MBP (18.4 kDa) increased in 4.8 times (p<0.001) with the use of L-arginine, in 10 times (p<0.001) - with aminoguanidine, in 13 times (p<0.001) - in cases of the combined use of L-arginine and aminoguanidine compare to the indices of the mice with antiphospholipid syndrome. It was proved that the content of MBP (95-110 kDa) in the samples of the cerebral hemispheres of the experimental animals did not significantly change compare to the control. In the cerebellum of the animals with antiphospholipid syndrome, it was established that the level of MBP (95-110 kDa) increased in more than 5 times (p<0.001), while the MBP (18.4 kDa) was found in very small amounts compare to the control. In cases of lone and combined use of nitric oxide synthesis modulators (L-arginine and aminoguanidine), there were no significant changes in the level of MBP (95-110 kDa) in the cerebellum of BALB/c mice with antiphospholipid syndrome compare to the indices of the BALB/c mice with antiphospholipid syndrome only.

Changes of nitric oxide synthase and hydrogen sulfide in blood lymphocytes in the acute period of polytrauma

INTRODUCTION

Polytrauma patients have high risk of shock, septic complications and death during few years of follow-up. In recent years a lot of attention is paid to gaseous transmitters, among which are nitrogen oxide (NO) and hydrogen sulfide (H2S). It is known that the rise of NO and its metabolites levels occurs during the acute period of polytrauma. Nitric oxide and hydrogen sulfide are produced in different cell types, among which are lymphocytes.

THE AIM

To investigate the levels of NO, NOS, iNOS, еNOS, H2S in lymphocytes lysate in patients at the moment of hospitalization and 24 hours after trauma.

MATERAL AND METHODS

We investigated the levels of NO, NO-synthase, inducible NO-synthase, endothelial NO-synthase, H2S in lymphocytes lysate in patients at the moment of hospitalization and 24 hours after trauma.

RESULTS

The study included 20 patients with polytrauma who were treated in the intensive care unit (ICU) of the Lviv Emergency Hospital. Tissue injury was associated with an increased production of NO, NOS, iNOS, еNOS during the acute period of polytrauma. At the same time, the level of H2S decreased by the end of the first day of traumatic injury.

CONCLUSIONS

In acute period of polytrauma, significant increasing of iNOS and eNOS occurs with percentage prevalence of iNOS over eNOS on the background of H2S decreasing.

Role of plasma asymmetric dimethyl-L-arginine levels in detection of pulmonary hypertension in children with CHD

OBJECTIVES

The objectives of this study were to evaluate the plasma levels of asymmetric dimethyl-L-arginine in children with pulmonary hypertension due to CHD before and after treatment with sildenafil and to evaluate its diagnostic and prognostic value as a biomarker in such children.

METHODS

A total of 60 children with CHD and 30 healthy control children matched for age and sex were recruited. Children with CHD were divided into two equal groups: the normal pulmonary pressure group (n=30) and the pulmonary hypertension group (n=30). Children with pulmonary hypertension were treated with sildenafil and were followed up for 6 months. Clinical data, haemodynamic parameters, echocardiographic examination, and asymmetric dimethyl-L-arginine levels were evaluated before and after treatment.

RESULTS

Asymmetric dimethyl-L-arginine levels were significantly higher in patients with pulmonary hypertension than in those with CHD-only or the control group, and this increase was positively correlated with increased severity of pulmonary hypertension. Asymmetric dimethyl-L-arginine levels, mean pulmonary artery pressure, and pulmonary vascular resistance were significantly decreased after treatment with sildenafil. Moreover, asymmetric dimethyl-L-arginine level was significantly lower in patients who responded to sildenafil treatment compared with those who did not. At a cut-off point of more than 0.85 nmol/ml, asymmetric dimethyl-L-arginine has a sensitivity of 83% and a specificity of 80% to diagnose pulmonary hypertension-CHD. Asymmetric dimethyl-L-arginine has a sensitivity of 100% and a specificity of 94% to predict poor prognosis in pulmonary hypertension-CHD children at a cut-off point of 1.3 nmol/ml.

CONCLUSION

Asymmetric dimethyl-L-arginine level has a good diagnostic and prognostic value as a biomarker in children with pulmonary hypertension-CHD and can be used for following up patients with pulmonary hypertension and predicting response to treatment.

Personal Ozone Exposure and Respiratory Inflammatory Response: The Role of DNA Methylation in the Arginase-Nitric Oxide Synthase Pathway

Little is known regarding the molecular mechanisms behind respiratory inflammatory response induced by ozone. We performed a longitudinal panel study with four repeated measurements among 43 young adults in Shanghai, China from May to October in 2016. We collected buccal samples and measured the fractional exhaled nitric oxide (FeNO) after 3-day personal ozone monitoring. In buccal samples, we measured concentrations of inducible nitric oxide synthase (iNOS) and arginase (ARG), and DNA methylation of NOS2A and ARG2. We used linear mixed-effect models to analyze the effects of ozone on FeNO, two enzymes and their DNA methylation. A 10 ppb increase in ozone (lag 0-8 h) was significantly associated with a 3.89% increase in FeNO, a 36.33% increase in iNOS, and a decrease of 0.36 in the average methylation (%5mC) of NOS2A. Ozone was associated with decreased ARG and elevated ARG2 methylation, but the associations were not significant. These effects were more pronounced among allergic subjects than healthy subjects. The effects were much stronger when using personal exposure monitoring than fixed-site measurements. Our study demonstrated that personal short-term exposure to ozone may result in acute respiratory inflammation, which may be mainly modulated by NOS2A hypomethylation in the arginase-nitric oxide synthase pathway.

Functional Layer-by-Layer Thin Films of Inducible Nitric Oxide (NO) Synthase Oxygenase and Polyethylenimine: Modulation of Enzyme Loading and NO-Release Activity

Nitric oxide (NO) release counteracts platelet aggregation and prevents the thrombosis cascade in the inner walls of blood vessels. NO-release coatings also prevent thrombus formation on the surface of blood-contacting medical devices. Our previous work has shown that inducible nitric oxide synthase (iNOS) films release NO fluxes upon enzymatic conversion of the substrate l-arginine. In this work, we report on the modulation of enzyme loading in layer-by-layer (LbL) thin films of inducible nitric oxide synthase oxygenase (iNOSoxy) on polyethylenimine (PEI). The layer of iNOSoxy is electrostatically adsorbed onto the PEI layer. The pH of the iNOSoxy solution affects the amount of enzyme adsorbed. The overall negative surface charge of iNOSoxy in solution depends on the pH and hence determines the density of adsorbed protein on the positively charged PEI layer. We used buffered iNOSoxy solutions adjusted to pHs 8.6 and 7.0, while saline PEI solution was used at pH 7.0. Atomic force microscopy imaging of the outermost layer shows higher protein adsorption with iNOSoxy at pH 8.6 than with a solution of iNOSoxy at pH 7.0. Graphite electrodes with PEI/iNOSoxy films show higher catalytic currents for nitric oxide reduction mediated by iNOSoxy. The higher enzyme loading translates into higher NO flux when the enzyme-modified surface is exposed to a solution containing the substrate and a source of electrons. Spectrophotometric assays showed higher NO fluxes with iNOSoxy/PEI films built at pH 8.6 than with films built at pH 7.0. Fourier transform infrared analysis of iNOSoxy adsorbed on PEI at pH 8.6 and 7.0 shows structural differences of iNOSoxy in films, which explains the observed changes in enzymatic activity. Our findings show that pH provides a strategy to optimize the NOS loading and enzyme activity in NOS-based LbL thin films, which enables improved NO release with minimum layers of PEI/NOS.

[PTPS gene analysis and prenatal diagnosis in patients with 6-pyruvoyl-tetra hydropterin synthase deficiency]

Objective: To analyze the variations of PTPS gene in patients with suspected 6-pyruvoyl-tetra hydropterin synthase deficiency (PTPSD) and to make prenatal diagnosis in high-risk families. Methods: Chemiluminescence was used for phenylalanine detection in blood or dried blood spots.Patients with phenylalanine concentration over 120 μmol/L were detected by urine pterin analysis, and the activity of dihydropteridine reductase (DHPR) was detected. tetrahydrobiopterin loading tests were performed in suspected patients with abnormal urinary pterin profiles. PTPS gene variation analysis was performed by direct Sanger sequencing based on PCR amplification. Prenatal diagnosis in 7 high-risk families was performed by chorionic villus sampling when the genotype was identified. Results: In 656 patients with hyperphenylalanine, 22 cases were diagnosed as PTPSD clinically. 16 variations were detected in the 22 PTPSD cases. The 5 variations, p.Lys77Arg, p.Ile84Phe, c.315-2A>G, c.244-2A>T, c.187-1G>T, were identified as novel variations. Two fetuses carried the same mutation with the proband and therefore were thought to be PTPSD fetuses. Three fetuses carried only one mutant allele and thus were thought to be PTPSD carriers. The other 2 fetuses carried no mutations and were presumed normal. Conclusions: PTPS gene variation analysis is necessary to confirm the diagnosis. Prenatal diagnosis could help avoiding the defect birth in PTPSD families.

High cholesterol diet leads to oxidant load and peroxidation in the rabbit kidney tissue

OBJECTIVES

The aim of this study was to investigate possible effects of high cholesterol diet on oxidant/antioxidant status in rabbit kidney tissues.

BACKGROUND

Although a number of experimental animal models have suggested that hyperlipidemia is associated with progressive kidney failure data remain sparse on the role of dietary cholesterol intake on kidney disease.

METHODS

Twelve male New Zealand albino rabbits were randomly divided into two groups (control and cholesterol). Both groups were fed on a standard laboratory diet. Animals in the cholesterol group additionally received cholesterol (1 g/kg/day), orally. The study period was 12 weeks. Activities of catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), nitric oxide synthase (NOS), xanthine oxidase (XO), paraoxonase (PON), adenosine deaminase (ADA) enzymes and levels of malondialdehyde (MDA) and nitric oxide (NO) were measured in kidney tissue samples. Histological examination of the kidney tissue samples was also done.

RESULTS

SOD, GSH-Px and XO enzyme activities were found to be decreased and NOS and PON activities increased significantly in cholesterol group compared to controls. As an indication of oxidation, MDA levels were found to be increased in cholesterol group. Histological examination revealed some derangements in the kidney tissue.

CONCLUSION

High cholesterol diet creates oxidant load and causes peroxidation, which in turn, leads derangements in the rabbit kidney tissue (Tab. 2, Fig. 2, Ref. 69).

[Alteration mechanisms of oxidative stress at periodontal tissues of rats in a simulated periodontitis and elaborate methods of their correction]

INTRODUCTION

one of the peroxidation stress mechanisms is inducible NO synthase (iNOS) expression involved in the pathogenesis of periodontitis.

AIM

to access the influence of isoform NO synthase (NOS) on alteration mechanisms of oxidative stress at periodontal tissues of 50 mature rats in a simulated periodontitis (SP).

MATERIALS AND METHODS

a SP at rats was induced by a high-carbohydrate, high-fat (HCHF) diet. Тreated SP rat groups were intragastrically administered with selective neuronal NOS (nNOS) inhibitor 7-nitroindazole, selective inducible NOS (iNOS) inhibitor aminoguanidine, and nitric oxide synthase substrate L-arginine. Oxidative stress level in the homogenated soft periodontal tissues was evaluated by TBARS (thiobarbituric acid reactive substances) level before and after 1,5 hours of incubation. Antioxidant response was evaluated by the increase in concentration of TBARS for incubation, аnd by antioxidant enzyme activity - superoxide dismutase and catalase.

RESULTS

nNOS activity increase in a SP considerably limits oxidative stress activation at periodontal tissues, decreases antioxidant response, but heightens catalase activity. iNOS functional activity stimulates oxidative stress at periodontal tissues of rats, decreases antioxidant response. L-arginine in a MS effectively repaired antioxidant response at periodontal tissues that probably will give positive result at complex treatment of periodontitis and MS generally.

CONCLUSIONS

in the near future, the appropriate regulation of NO activity by using NOS-active agents may provide a novel strategy for the periodontal disease prevention and correction in a MS.

[COMPARATIVE MORPHOFUNCTIONAL CHARACTERISTICS OF ADULT AND OLD RAT VENTRAL HIPPOCAMPUS TO COMBINED STRESS INFLUENCE]

Animals were subjected to seven days combined stress in a special chamber (6 isolated compartments of equal area) with removable multi-modal stressors (noise, vibration, pulsating bright light) every 5 minutes on the stochastic scheme with restraint and temperature rise in the chamber during 30-minute stressing time sessions. After exposure to combined stress in the ventral hippocampus of old rats (24 months) compared with adult animals (12 months) following changes were revealed: marked dystrophic changes and increased inducible nitric oxide synthase expression in pyramidal neurons of CA3 field, signs of impaired hemodynamic disorders in the microvasculature, perivascular edema, decreased endothelial nitric oxide synthase expression in microvascular endothelial cells, as well as decreased expression of serine racemase in the neuropil of the radial layer of CA1 field.

The influence of a nitric oxide synthase inhibitor and endothelin receptor blocker on the free sulfhydryl groups content in lung homogenates

INTRODUCTION

The aim of the study was to assess the influence of the nitric oxide synthase inhibitor L-NAME and the endothelin receptor blocker BQ123 on the free sulfhydryl (-SH) groups content in rat lung homogenates.

MATERIAL AND METHODS

Experiments were performed on Wistar-Kyoto rats divided into the following groups: group I (control) received (i.v.) saline; group II (ET-1) received (i.v.) endothelin 1 (3 g μg/kg b.w.); group III (BQ123+ET-1) received (i.v.) ET(A) receptor blocker (1 mg/kg b.w.) + endothelin 1 (3 g μg/kg b.w.); group IV (L-NAME+ET-1) received (i.v.) nitric oxide synthase inhibitor (5 mg/kg b.w.) + endothelin 1 (3 μg/kg b.w.).

RESULTS

Administration of BQ123 at a dose of 1 mg/kg b.w. resulted in a statistically significant increase in the concentration of -SH groups (p<0.001 vs. ET-1). L-NAME (5 mg/kg b.w.) also significantly increased the level of -SH groups in the lungs of rats during oxidative stress induced ET-1 (p<0.001).

DISCUSSION

The nitric oxide synthase inhibitor L-NAME at a dose of 5 mg/kg b.w. and the endothelin receptor blocker BQ123 at a dose of 1 mg/kg b.w. showed a significant increase in the concentration of -SH groups in the lungs, which may be associated with an increase in synthesis of proteins containing sulfhydryl groups.