Gas6 expression and Tyrosine kinase Axl Sky receptors: Their relation with tumor stage and grade in patients with bladder cancer.

OBJECTIVES: It has been shown that the dysregulation of tyrosine kinase Axl receptor and its ligand growth arrest-specific gene (Gas6) are associated with poor prognosis in various types of tumors but there is not enough study about their importance in bladder cancer (BC). We evaluated the relation of Gas6 gene expression and tyrosine- kinase Axl and Sky (Tyro 3) receptors with tumor stage and grade in patients with BC. MATERIAL AND METHODS: The study group consists of 55 patients whose transurethral resection of bladder (TUR-B) has been performed due to BC and the control group consists of 12 patients with normal bladder mucosa. In tissues mRNAs of Gas6, Axl, and Sky receptors were examined by quantitative (Real-Time) PCR (qPCR). Protein expression was measured by immunohistochemistry. Plasma Gas6 protein levels were compared with control group by ELISA method. RESULTS: Patients with BC were grouped as Ta low (n=17), Ta high (n=5), T1 low (n=9), T1 high (n=8) and T2 (n=16) according to their TUR-B pathologies. The qPCR analysis showed that the expression of Gas6 gene and Axl receptor is higher in the tumor-positive group and the immune-histochemical showed that the bladder samples of the tumor-positive group stained significantly positive. When the patients are grouped according to the TUR-B pathologies, a statistical significant difference was observed among groups in the qPCR analysis ratios of Gas6 gene and Axl receptor by (p < 0.05) but no significance was found for Sky receptor (p > 0.05). When Gas6 protein levels in plasma samples were compared by ELISA method, a statistical significance was determined among groups (p = 0.001). CONCLUSIONS: Our findings indicate that mRNAs of Gas6 and Axl receptor are closely related to tumor stage and grade in patients with BC. Further studies are needed for understanding the role of Gas6 and its receptors on the neoplastic transformation in terms of novel biomarkers and potential therapeutic targets.

Plasma growth arrest-specific 6 levels in term and preterm newborns.

OBJECTIVE: Growth Arrest-Specific 6 (GAS6) is a vitamin K-dependent protein. Despite a similar structure to Protein S, it has no anticoagulant activity. An association between GAS6 and some diseases for adults has been reported. In the absence of prospective clinical studies of GAS6 in neonates, so far, the objective of this study is to obtain, for the first time, plasma GAS6 levels before and after vitamin K1 prophylaxis in full-term and pre-term newborns. METHODS: 80 newborns (40 term and 40 preterm) were recruited for this study. Cord blood samples and peripheral blood samples 48 h after vitamin K1 injection were collected into EDTA-tubes. GAS6 levels were measured in platelet-poor plasma by ELISA. RESULTS: Cord blood plasma GAS6 levels in preterm and term newborns were 9.07 ± 5.30 ng/mL and 9.75 ± 4.34 ng/mL, respectively. In response to vitamin K1 injection, GAS6 levels increased in preterm newborns (10.50 ± 5.28 ng/mL) (p < .05), but not in term newborns (9.12 ± 3.42 ng/mL, p > .05). CONCLUSION: This pilot study provided, to the best of our knowledge, the first report that GAS6 levels increased significantly after vitamin K1 prophylaxis in preterm newborns but not in term infants. This study may serve as a first step toward more extensive studies in neonates.

Reference intervals for growth arrest-specific 6 protein in adults.

The objective of this study was to establish reference intervals for growth arrest-specific 6 (GAS6), a vitamin K-dependent protein, in human adult plasma according to the Guideline of Clinical and Laboratory Standards Institute (CLSI) C28-A3. Blood samples were collected from 308 healthy volunteers aged 18-72 (157 female, 151 male). A non-parametric approach was used to calculate the reference interval. The plasma GAS6 reference interval was determined, with 90% confidence interval: the lower limit (2.5 percentile) was 2.5 (1.9-3.1) µg/L and the upper limit (97.5 percentile) = 18.8 (18.0-22.3) µg/L. Harris-Boyd's test did not suggest partitioning by age or gender: medians for males [7.8 (5.8-10.7) µg/L] and females [9.9 (7.1-13.5) µg/L]. Three age-subgroups were tested: 18-29 years (n = 168); 30-44 years (n = 73); 45-72 years (n = 67). The intra- and inter-assay variations were 12.6% (mean, 5.2 ± 0.7 µg/L) and 14.0% (mean, 9.2 ± 1.3 µg/L), respectively. The mean recovery was 104%. This study reports plasma GAS6 reference intervals established first according to the guideline of CLSI C28-A3.

Ethanol extract of Cotinus coggygria leaves accelerates wound healing process in diabetic rats.

CONTEXT: Cotinus coggygria Scop. (Anacardiaceae) leaves that were used as wound healing in traditional Balkan and Anatolian folk medicine, could be potentially effective in treating diabetic wounds. OBJECTIVE: This study investigates biochemical and histological effects of ethanol extract of C. coggygria (CCE) on excision wound model in diabetic rats. MATERIALS AND METHODS: This study was conducted on diabetic Wistar albino rats, which were injected by a single dose (50 mg/kg i.p.) streptozotocin. Afterward an excision wound model was created in all animals; diabetic control rats were applied topically simple ointment and diabetic treatment rats were applied topically 5% (w/w) ointment with CC, once a day during the experimental period. Malondialdehyde, glutathione and hydroxyproline levels in wound tissues were investigated at the end of 3rd, 7th, and 14th days. Histopathological examination was also performed. RESULTS: Hydroxyproline content was significantly increased in the CCE treated group versus control after the 3rd and 7th days (15.33 versus 11.83; 19.67 versus 15.67 mg/g, p < 0.05; respectively). A statistically significant elevation in glutathione at the end of 3rd, 7th, and 14th days (5.13 versus 1.58, p < 0.05; 4.72 versus 1.88, p < 0.05; 3.83 versus 1.88 µmol/g, p < 0.05, respectively) and a statistically significant decrease in malondialdehyde level at the end of 7th day (4.49 versus 1.48 nmol/g, p < 0.05) were determined in the treated group versus control group. These results were also supported by histological analyses. DISCUSSION AND CONCLUSION: These findings indicate that CCE accelerated the cutaneous wound healing process in diabetic wounds, in confirmation of its traditional use.

The effect of topical ethanol extract of Cotinus coggygria Scop. on cutaneous wound healing in rats.

The aim of this study is to determine the cutaneous wound healing effects of the ethanol extract of Cotinus coggygria leaves in rats by excision wound model to provide scientific evidence for the traditional use of C. coggygria Scop. The levels of malondialdehyde, catalase, superoxide dismutase, glutathione and hydroxyproline were investigated in wound tissues. Histopathological examination was also performed. The hydroxyproline content of the granulation tissue and the glutathione levels were both significantly higher in the treatment group than in the control group (p < 0.05 for both); while the malondialdehyde levels were significantly lower in the treatment group (p < 0.05). These results were supported with histological results. The ethanol extract of C. coggygria Scop could be considered as an effective agent in wound healing in accordance with its traditional use.

Association between the growth arrest-specific 6 (Gas6) gene polymorphism c.834 + 7G>A and preeclampsia.

OBJECTIVE: Preeclampsia (PE) is a hypertensive disease of pregnancy complicating 2-8% of all pregnancies. The exact pathophysiology still remains unknown. Growth arrest-specific 6 (Gas6) is a member of the vitamin K-dependent protein family and it has been suggested as a novel atherothrombotic risk factor with anti-angiogenic and pro-atherogenic properties. The goal of the our study was to investigate the relationships between the c.834 + 7G > A polymorphism of GAS6, plasma Gas6 levels and PE. METHODS: A total of 150 women, including 82 preeclamptic pregnant women and 68 normotensive pregnant (NP) women, were recruited in the current study. Blood samples were taken from all participants. Plasma Gas6 levels measured by an enzyme-linked immunosorbent assay. GAS6 polymorphism was determined using a PCR-RFLP method. RESULTS: The plasma Gas6 levels of preeclamptic patients were significantly lower than those of NP women (8.65 ± 3.70 ng/ml and 10.89 ± 4.23 ng/ml respectively, p < 0.001). The GG genotype was the most prevalent, and the risk of PE was 3.5-fold higher in pregnant women with GG genotype compared to woman with AA genotype (p < 0.01). The A allele was less frequent in preeclamptic patients than in control subjects (OR = 2.118, 95% CI = 1.330-3.371, p < 0.001). CONCLUSIONS: Our results suggest that GAS6 c.834 + 7G > A polymorphism may have a pivotal role in the pathogenesis of PE suggesting that the A allele has a protective role for PE.

Growth Arrest-Specific 6 (Gas6) and TAM Receptors in Mouse Platelets.

OBJECTIVE: Growth arrest-specific 6 (Gas6) is a newly discovered vitamin K-dependent protein, which is a ligand for TAM receptors [Tyro3 (Sky), Axl, and Mer] from the tyrosine kinase family. Gas6 knockout mice were resistant to venous and arterial thrombosis. There are contradictory reports on the presence of Gas6 and its receptors in mouse platelets. The objective of this study was to investigate whether Gas6 and its receptors were present in mouse platelets or not. MATERIALS AND METHODS: Specific pathogen-free BALB/c male and female mice of 8-10 weeks old and 25-30 g in weight were anesthetized under light ether anesthesia and blood samples were taken from their hearts. RNAs were isolated from isolated platelets, and then mRNAs encoding Gas6 and TAM receptors were detected by reverse transcription-polymerase chain reaction (RT-PCR). Protein concentrations of Gas6 and TAM receptors in platelets were measured by ELISA, but not those of Mer, because of the absence of any commercial ELISA kit for mouse specimens. RESULTS: RT-PCR results indicated the presence of mRNAs encoding Gas6 and Mer in mouse platelets. However, although RT-PCR reactions were performed at various temperatures and cycles, we could not detect the presence of mRNAs encoding Axl and Tyro3 (Sky). Receptor protein levels of Axl and Tyro3 were below the detection limits of the ELISA method. CONCLUSION: We found the presence of mRNAs encoding Gas6 and the receptor Mer in mouse platelets, but not Axl and Tyro3. Gas6, Axl, and Tyro3 protein levels were below the detection limits of the ELISA. The presence of mRNA is not obvious evidence of protein expression in platelets that have no nucleus or DNA. Further studies are required to clarify the presence of Gas6/TAM receptors in platelets using real-time PCR and more sensitive immunological methods, and future studies on mechanisms will indicate whether the Gas6/TAM pathway is a strategy for treatment of disorders.

Growth arrest-specific 6 and cardiometabolic risk factors in patients with psoriasis.

OBJECTIVES: An increased risk for cardiovascular disease with psoriasis has been reported. Growth Arrest-Specific 6 (GAS6) amplifies pro-inflammatory endothelial cell activation via TAM receptors. However, it also inhibits inflammation by multiple mechanisms including phagocytosis. The objective of this study was to investigate whether plasma GAS6 levels are associated with conventional cardiometabolic (CM) risk factors in patients with psoriasis. METHODS: Forty patients diagnosed with psoriasis (22 male, mean age: 43.3 ± 13.8 years) and 40 age-/sex-matched healthy controls (22 male, mean age: 39.3 ± 8.9 years) were included in the study. CM risk factors (hypertension, hyperlipidemia, diabetes mellitus, and cigarette smoking) were identified. GAS6 levels were measured by ELISA. RESULTS: There were no significant differences between the plasma GAS6 levels of patients with psoriasis compared to the control group (6.6 ± 2.0 ng/mL, 7.6 ± 2.8 ng/mL, respectively, P > 0.05). However, GAS6 levels of patients with psoriasis having a smoking history (n = 11) were significantly lower than both patients with psoriasis who had no smoking history (n = 29) and controls (5.5 ± 1.7 ng/mL, 6.9 ± 1.9 ng/mL, 7.6 ± 2.8 ng/mL, respectively, P < 0.05). Similarly, psoriasis patients with at least one CM risk factor showed lower GAS6 levels compared to subjects without any CM risk factor (5.7 ± 1.7 ng/mL, 7.3 ± 2.0 ng/mL, P < 0.01). There was no correlation between the GAS6 level, disease duration or PASI score (r = 0.150, -0.150, and P = 0.310, 0.398, respectively). CONCLUSIONS: This pilot study provides the first evidence in humans for an association between low plasma GAS6 levels and conventional risk factors in psoriasis. Further large scale, prospective studies are needed to confirm these results.

The impact of platelet functions and inflammatory status on the severity of preeclampsia.

OBJECTIVE: To find out whether there is a correlation between the extent of platelet activation and inflammation and the severity of preeclampsia (PE) in the third trimester of pregnancy. METHODS: Forty-one women with PE (n = 23 severe, n = 18 mild) and 80 normotensive pregnant (NP) women were included in the study. Their blood samples were obtained and interleukin (IL)-8 and IL-10 levels measured by an enzyme-linked immunosorbent assay. Basal CD61 and CD62P expressions on CD41-positive platelets were analyzed with the use of flow-cytometry. Platelet aggregation was induced by adenosine diphosphate and determined by aggregometry. RESULTS: CD62P expression was increased in severely preeclamptic women, and the platelet aggregation was decreased in both mildly and severely preeclamptic women in comparison with NP women. However, CD61 expression was similar among the groups. An enhanced inflammatory response was seen in severely preeclamptic women demonstrated by increased levels of IL-8 and decreased levels of IL-10. However, the intensity of platelet activation did not correlate directly with the change in plasma levels of IL-8 and IL-10 in preeclamptic women. CONCLUSIONS: Platelets may have a role in the inflammatory response in PE. However, the severity of inflammation is found to be independent from the intensity of platelet activation in preeclamptic women. This seems to be related to mechanisms causing alterations of cytokine levels such as IL-8 and IL-10, rather than platelet activation.

Association of plasma growth arrest-specific protein 6 (Gas6) concentrations with albuminuria in patients with type 2 diabetes.

AIMS: New biomarkers are required to detect diabetic nephropathy earlier in persons with type 2 diabetes mellitus. Recent experimental studies indicate that growth arrest-specific protein 6 (Gas6) may have a role in pathogenesis of complications associated with diabetes. The objective of the current study is to examine whether plasma Gas6 concentrations are associated with albuminuria in persons with type 2 diabetes mellitus. METHODS: About 32 patients with diabetes which have micro or macroalbuminuria, 37 patients with diabetes and normoalbuminuria, and 30 healthy volunteers were recruited. Plasma Gas6 levels were measured by ELISA. Hemoglobin A1c (HbA1c), serum C reactive protein, fibrinogen and 24-h urine samples for microalbuminuria were analyzed by Primus PDQ, Beckman Coulter Immage 800, STA Compact and Roche Cobas Integra 800 analyzer, respectively. Statistical analysis was performed using SPSS (Statistical Package for Social Sciences) for Windows 11.5. RESULTS: There was a noteworthy difference among the three groups for Gas6 according to the Kruskal-Wallis test (p < 0.01). Plasma Gas6 concentrations were higher in patients with micro or macroalbuminuria [20.9 ng/mL (16.7-27.0); median (25-75% percentile)] compared to patients with normoalbuminuria [16.5 ng/mL (13.1-22.9)], and healthy controls [15.3 ng/mL (8.3-33.6)]. CONCLUSIONS: In conclusion, this is the first study indicating that plasma Gas6 levels are associated with albuminuria in patients with type 2 diabetes. This study could be considered a starting point to focus on the association between Gas6 and diabetic nephropathy.

The protective effects of tacrolimus on rat uteri exposed to ischemia-reperfusion injury: a biochemical and histopathologic evaluation.

OBJECTIVE: To evaluate the effects of the immunosuppressant tacrolimus as an antioxidant and analyze the histopathologic changes in rat uteri exposed to experimental ischemia-reperfusion (I/R) injury. DESIGN: Experimental study. SETTING: Experimental surgery laboratory in a university. ANIMAL(S): Twenty-eight female rats exposed to experimentally induced uterine I/R injury. INTERVENTION(S): Group I: control group; group II: uterine I/R injury-induced group; group III: pre-ischemia tacrolimus group; group IV: post-ischemia tacrolimus group. MAIN OUTCOME MEASURE(S): Uterine tissue malondialdehyde (MDA) level as a marker of lipid peroxidation and glutathione (GSH) level and superoxide dismutase (SOD) and catalase (CAT) activities as markers of tissue antioxidant capacity; histopathologic examination of all uterine rat tissue. RESULT(S): Following aortic I/R injury, MDA levels were significantly increased whereas GSH levels and CAT and SOD activities were found to be decreased compared with control animals. MDA levels were found to recover prominently after the administration of tacrolimus in both groups III and IV. Administration of tacrolimus improved uterine GSH levels and CAT activity in the tacrolimus-treated groups. CONCLUSION(S): Our results indicate that tacrolimus reduces oxidative damage in rat uteri exposed to I/R injury induced by distal abdominal aortic occlusion. Histologic evaluation reveals that tacrolimus attenuates the inflammatory response and protects the tissue damage induced by I/R injury.

Determinants of the tumor suppressor INPP4B protein and lipid phosphatase activities.

The tumor suppressor INPP4B is an important regulator of phosphatidyl-inositol signaling in the cell. Reduced INPP4B expression is associated with poor outcomes for breast, prostate, and ovarian cancer patients. INPP4B contains a CX5R catalytic motif characteristic of dual-specificity phosphatases, such as PTEN. Lipid phosphatase activity of INPP4B has previously been described. In this report we show that INPP4B can dephosphorylate para-nitrophenyl phosphate (pNPP) and 6,8-difluoro-4-methylumbelliferyl (DiFMUP), synthetic phosphotyrosine analogs, suggesting that INPP4B has protein tyrosine phosphatase (PTP) activity. Using mutagenesis, we examined the functional role of specific amino acids within the INPP4B C842KSAKDR catalytic site. The K843M mutant displayed increased pNPP hydrolysis, the K846M mutant lost lipid phosphatase activity with no effect on PTP activity, and the D847E substitution ablated PTP activity and significantly reduced lipid phosphatase activity. Further, we show that INPP4B but not PTEN is able to reduce tyrosine phosphorylation of Akt1 and both the lipid and PTP activity of INPP4B likely contribute to the reduction of Akt1 phosphorylation. Taken together our data identified key residues in the INPP4B catalytic domain associated with lipid and protein phosphatase activities and found a robust downstream target regulated by INPP4B but not PTEN.

Exogenous L-arginine and HDL can alter LDL and ox-LDL-mediated platelet activation: using platelet P-selectin receptor numbers.

The aim of this study is to investigate the effects of exogenous L-arginine and HDL on LDL and oxidized LDL (ox-LDL)-mediated platelet activation. Adenosine diphosphate (ADP)-activated platelets have been incubated with lipoproteins with or without L-arginine. P-selectin receptor numbers per platelet have been measured by flow cytometry. After incubation with only L-arginine (without lipoproteins), platelet nitric oxide (NO) levels and P-selectin receptor numbers significantly increased compared to the controls (P < .05). After incubation with LDL or ox-LDL, receptor numbers of P-selectin significantly increased (P < .001). However, P-selectin receptor numbers in platelets treated with L-arginine + LDL or L-arginine + ox-LDL decreased compared to the levels in platelets treated with only LDL or ox-LDL (P < .01, P < .001, respectively). Addition of HDL to L-arginine + ox-LDL caused significant reduction in P-selectin receptor numbers as in the control values (P < .001).We have concluded that L-arginine causes enhanced platelet NO levels and blocks the effects of LDL or ox-LDL on platelet P-selectin receptor numbers and HDL also strengthens this effect of L-arginine.

New in vitro effects of clopidogrel on platelets in hyperlipidemic and healthy subjects.

OBJECTIVE: We aimed to detect novel in vitro effects of clopidogrel on platelets by assessment of the following parameters: malondialdehyde, glutathione, nitrite, aggregation response, and expressions of P-selectin, fibrinogen, apolipoprotein A1, apolipoprotein B, and phosphatidylserine. METHODS: Platelets were obtained from healthy (n: 9) and hyperlipidemic (n: 9) volunteers. Expressions of P-selectin, fibrinogen, apolipoproteins A1/B and phosphatidylserine with and without clopidogrel were assayed by flow cytometry. Malondialdehyde, glutathione, aggregation and nitrite levels were also assayed. RESULTS: Without clopidogrel, the baseline values of platelet aggregation, malondialdehyde, and expressions of P-selectin, fibrinogen and phosphatidylserine were significantly higher, whereas nitrite and expression of apolipoproteins A1/B were significantly lower in hyperlipidemics than in the healthy group. In both groups, clopidogrel significantly reduced aggregation and expression of fibrinogen, but it elevated nitrite levels. Clopidogrel significantly decreased P-selectin and phosphatidylserine expression and malondialdehyde but increased expressions of apolipoproteins A1/B only in hyperlipidemics. CONCLUSION: It seems that clopidogrel has some new in vitro antiplatelet effects. The present study is a basic in vitro study to suggest new insights into the effects of clopidogrel on platelet functions.

Quality regulations and accreditation standards for clinical chemistry in Turkey.

OBJECTIVE: The purpose of this paper is to review the current status of laboratory quality regulations and accreditation standards in Turkey. DESIGN AND METHOD: This paper is written based on the current regulations, information collected by available websites and congress proceedings, and personal communications. RESULTS: A total of 14 private and one public laboratory have been accredited according to ISO 15189 voluntarily. The total number of the JCI accredited hospitals is 24. One hospital has been accredited by HQS. A few medical laboratories have been accredited according to ISO 17025, whereas a lot of them have ISO 9001 certification from Turkish Accreditation Agency, TURKAK. There are no comprehensive laboratory standards and/or regulations to maintain a mandatory minimum quality of laboratories. External QC is not mandatory and there is no national proficiency testing program. It is a requirement to get a license to open a laboratory. There are residency programs for clinical chemistry and clinical microbiology. The Association of Clinical Biochemists, KBUD, is the youngest society in the field of clinical chemistry and is a leader in quality and accreditation activities. KBUDEK is an external QC program of KBUD. KBUD has organized four national and an international symposiums on quality and accreditation in addition to annual congresses and courses. CONCLUSION: The new standard and regulation should be designed and applied to all laboratories to increase the quality of laboratory service in Turkey. It will be useful if the ISO 15189 standard can be incorporated into the national standards and regulations.

Low-density lipoprotein specifically binds glycoprotein IIb/IIIa: a flow cytometric method for ligand-receptor interaction.

Primary platelet aggregation requires agonist-mediated activation of membrane receptor glycoprotein (GP) IIb/IIIa, binding of fibrinogen to GpIIb/IIIa, and cellular events after fibrinogen binding. This study investigated whether fibrinogen receptor GpIIb/IIIa is also the binding site for low-density lipoprotein (LDL) in platelets by using GpIIb/IIIa-coated polystyrene microbeads incubated with various concentrations of fluorescein isothiocyanate (FITC)-labeled ligands. Binding was assayed by flow cytometry. Binding of fibrinogen (Fg)-FITC and LDL-FITC to GpIIb/IIIa coated microbeads was concentration dependent, reaching saturation. Binding of LDL-FITC to GpIIb/IIIa coated microbeads was inhibited by fibrinogen. Binding of LDL-FITC or Fg-FITC to freshly isolated platelets gave similar results as those of GpIIb/IIIa coated microbeads. Glycoprotein IIb/IIIa, the fibrinogen receptor on platelets is also one of the binding sites of LDL on platelets. This rapid and reliable flow cytometric technique using coated microbeads may be used as a first step for the study of all ligand receptor interactions.

Relationship between Helicobacter pylori status and serum pepsinogens as serologic markers in atrophic gastritis.

BACKGROUND/AIMS: Serum pepsinogen levels are considered as a non-endoscopic blood test in the diagnosis of atrophic gastritis. The objective of the present study was to investigate whether there is any difference between pepsinogen levels in Helicobacter pylori-positive and -negative patients with atrophic gastritis, and to analyze the relationship between histopathology and pepsinogen levels after treatment in H. pylori-positive patients with atrophic gastritis. METHODS: The study enrolled a total of 30 cases with atrophic gastritis (18 H. pylori-positive and 12 H. pylori-negative). The H. pylori-positive cases received a one-week eradication treatment. Initially for all and after the treatment for H. pylori-positive cases, serum pepsinogen I and II levels, anti-H. pylori IgG titration and histopathologic analysis were carried out. RESULTS: In the H. pylori-positive patients with atrophic gastritis, the levels of pepsinogen I and pepsinogen I/II ratio were lower while the levels of pepsinogen II were higher compared to the H. pylori-negative patients (p<0.05 for all). The post-treatment serum pepsinogen I levels and pepsinogen I/II ratios did not change in the H. pylori-positive group, while the levels of pepsinogen II, H. pylori antibody titration and gastric atrophy degree remarkably decreased (p<0.05 for all). CONCLUSIONS: In atrophic gastritis, the levels of serum pepsinogen and pepsinogen I/II ratio show a difference in H. pylori-negative versus -positive cases. Additionally, the usage of pepsinogen II as a serum marker in predicting the eradication of H. pylori with atrophic gastritis could be more reliable than pepsinogen I or the I/II ratio.

A novel antioxidant N-acetylcysteine amide prevents gp120- and Tat-induced oxidative stress in brain endothelial cells.

Free radical production and, consequently, oxidative stress play an important role in the pathogenesis of AIDS and cause damage to lipids, proteins, and DNA. In our previous study, the HIV-1 envelope glycoprotein (gp120) and transregulatory protein (Tat) of HIV-1 have been found to induce oxidative stress in an immortalized endothelial cell line from rat brain capillaries, RBE4 (in vitro model of the blood-brain barrier). Here, we have determined the effects of a novel antioxidant, N-acetylcysteine amide (NACA), on gp120- and Tat-induced oxidative stress. Various oxidative stress parameters, including reduced glutathione (GSH), oxidized glutathione (GSSG), catalase (CAT) activity, and glutathione reductase (GR) activity, as well as malondialdehyde (MDA) levels, were used as measures of oxidative stress. NACA significantly increased the levels of intracellular GSH, CAT, and GR and decreased the levels of MDA in RBE4 cells, showing that oxidatively challenged cells were protected. Gp120- and Tat-induced increases in intracellular reactive oxygen species (ROS) were observed by using the 2',7'-DCF assay; the ROS scavenger, NACA, blocked ROS generation. A well-known apoptosis indicator, caspase-3 activity, was measured and was also found to have been returned to its control levels by NACA. Treatment of RBE4 cells with gp120 and Tat caused an increase in toxicity, as measured by lactate dehydrogenase (LDH) and tetrazolium reduction (MTS) assays. HIV-1 protein-induced toxicity in these cells was blocked by treatment with NACA. These studies show that NACA reverses gp120- and Tat-induced oxidative stress in immortalized endothelial cells.

Influence of serum folic acid levels on plasma homocysteine concentrations in patients with rheumatoid arthritis.

The purpose of this study was to investigate whether negative effects of methotrexate (mtx) on blood homocysteine (hmc) levels can be prevented with the replacement of folic acid. 42 female patients with rheumatoid arthritis (RA) were studied. Patients were separated into two groups according to their treatment status with mtx (group I: 27 patients taking mtx and folic acid; group II: 15 patients not using mtx). The level of hmc was found to be 6.3+/-2.4 micromol/l in group I and 7.87+/-3.2 micromol/l in group II (p>0.05). Folic acid levels of group I and II were found to be 21.3+/-15.9 ng/ml and 8.41+/-2.86 ng/ml respectively (p<0.001). There was a statistically-significant correlation between age and hmc levels (r=0.386, p=0.012). Negative statistically-significant correlations were observed between folic acid and hmc levels. The effects of mtx on hmc can be prevented with the replacement of folic acid.

Do platelet apoptosis, activation, aggregation, lipid peroxidation and platelet-leukocyte aggregate formation occur simultaneously in hyperlipidemia?

OBJECTIVES: The circulating lipoproteins may cause some abnormalities in platelet composition and function in hypercholesterolemia. The aim of this study was to investigate whether platelet apoptosis, platelet activation, platelet aggregation, platelet-leukocyte aggregate (PLA) formation and lipid peroxidation occur simultaneously in hyperlipidemia. DESIGN AND METHODS: Expression of GpIIb/IIIa (CD41a), P-selectin (CD62-P), platelet-bound fibrinogen (antifibrinogen), platelet membrane phosphatidylserine (PS), platelet-monocyte aggregates (mono-PLA) and platelet-neutrophil aggregates (neut-PLA) was measured in eight hyperlipidemic and eight normal subjects using flow cytometry. ADP (10 microM) was used to activate platelets. Furthermore, ADP induced platelet aggregation responses, platelet malondialdehyde (MDA) and glutathione (GSH) levels were determined. RESULTS: Before platelet activation, platelet CD62-P, antifibrinogen, annexin-V, mono-PLA, neut-PLA and platelet MDA levels as well as platelet aggregation responses in the hyperlipidemics were significantly higher than those in the controls (P<0.01, P<0.01, P<0.01, P<0.001, P<0.001, P<0.01, P<0.001, respectively), whereas GpIIb/IIIa expression and GSH levels were not different significantly (P > 0.05). In the control group, CD62-P, antifibrinogen and annexin-V levels increased significantly after ADP activation (P<0.05, P<0.05, P<0.01, respectively). In hyperlipidemic subjects, annexin-V expression increased significantly after activation (P<0.01), whereas expression of GpIIb/IIIa, CD62-P and antifibrinogen remained unchanged (P>0.05). The levels of total cholesterol (T-CHO), low density lipoprotein cholesterol (LDL-C), serum fibrinogen (S-FGN) and high density lipoprotein cholesterol (HDL-C) in patients were found to be correlated with platelet CD62-P, antifibrinogen, annexin-V, mono-PLA and MDA. CONCLUSIONS: In conclusion, it seems that in hyperlipidemia, some platelets are in an activated state in circulation, and that increased lipid peroxidation, early apoptosis, platelet-leukocytes aggregate formation and platelet aggregation altogether accompany this process.