conditions in myographs. Vascular segments were tested in the presence of the following inhibitor... more conditions in myographs. Vascular segments were tested in the presence of the following inhibitors: eNOS inhibitor L-NAME (100 μM), selective thromboxane receptor antagonist SQ 29,548 (1 μM), ceramidase inhibitor D-erythro-MAPP (50 μM), PI3-kinase inhibitor Wortmannin (0.1 μM), Akt-inhibitor MK2206 (1 μM), PLC inhibitor U73122 (10 μM) and cystathionine-γ-lyase (CSE) inhibitor propargylglycine (10 mM). We also tested the effects of sodium hydrosulfide (NaHS, 10 −5 − 10 −3 M) and sodium nitroprusside (SNP, 10 −10 − 10 −5 M) after precontraction induced by 1 μM phenylephrine in isometric condition in myographs. L-NAME administration completely abolished while SQ 29,548 increased relaxations in both groups, but especially in the db/db group. The use of D-erythro-MAPP, Wortmannin and MK2206 did not alter the vasoactive effects of SMase in control and db/db derived vessels, while U73122 completely inhibited the relaxations in diabetic aortas. The inhibition of H2S production led to less relaxation in db/db vessels but had no effect on control vessels. Dose-response curves for NaHS were shifted to the left while dose-response curves for SNP were shifted to the right in the db/db group. Our results indicate that H2S contributes to the SMase induced and surprisingly enhanced vasorelaxations in db/db animal derived aortas. The altered dose-response curves for NaHS and SNP suggest that phosphodiesterase activity might be enhanced in the aortas of db/db mice. This suggests decreased availability of its endogenous inhibitor H2S and indicates that sphingomyelinase might lead to enhanced vasorelaxations by massively increased NO production. An interesting aspect of our results is that diabetic vascular tissues have bigger sensitivity to either endogenously or exogenously altered H2S levels. Taken together our observations strengthen the importance to achieve proper H2S levels in diabetic vascular tissues.
Introduction: Vascular oxygen sensing has been attributed to hypoxic generation of reactive oxyge... more Introduction: Vascular oxygen sensing has been attributed to hypoxic generation of reactive oxygen species (ROS) which oxidize the cytosol and reduce the mitochondrial matrix (Waypa et al., 2010 [1]). However, H2S and polysulfides (H2Sn) have also been shown to affect redox status (Greiner et al., 2013 [2]). We hypothesize that reactive sulfur species (RSS) have the same effect on redox status as ROS and propose that this supports our hypothesis that the metabolism of H2S is the vascular oxygen sensor (Olson, 2015 [3]). Methods: In this study, we examined the effects of H2S (Na2S) and mixed H2Sn (K2Sn) on redox status of the redox sensitive green fluorescent protein (roGFP) purified from Escherichia coli (roGFP-E) using~40% and 100% oxidized protein incubated in either normoxia (21% O2) or anoxia (0% O2). We also examined the effects of H2S and H2Sn on roGFP inserted into either the cytoplasm (roGFP-C) or mitochondrial matrix (roGFP-M) of HEK-293 cells. Results: 1-300 μM H2S had no effect on roGFP-E whereas 40% oxidized roGFP-E was further oxidized by 1 mM H2S and completely oxidized by H2S >1 mM in both 21 and 0% O2. H2Sn oxidized roGFP-E at considerably lower concentrations (>3 μM) and independently of O2 availability. We saw no evidence for roGFP-E reduction by either H2S or H2Sn. Conversely, 10 μM H2S and above oxidized roGFP-C and reduced roGFP-M in-vitro; H2Sn reduced roGFP-C and roGFP-M at concentrations <1 mM and oxidized them at concentrations >1 mM. Conclusions: 1. H2S is not an efficient reductant, particularly in cells. 2. The time course of H2S activation is inconsistent with a preexisting polysulfide contaminant, but because H2S cannot be an oxidant, we conclude that H2S must somehow react with roGFP-E to produce an oxidant, probably a polysulfide. 3. The oxidizing ability of H2S is O2-independent. 4. The increased efficacy of H2S compared to H2Sn in HEK-293 cells may be due to rapid permeation of H2S. 5. The effects of hypoxia on intracellular redox status is mimicked by exogenous H2S, providing additional support to our hypothesis of H2S metabolism as the O2 sensor.
Introduction: The influence of psychological factors on the patient experience of AF has been dem... more Introduction: The influence of psychological factors on the patient experience of AF has been demonstrated to be in excess of the objective burden of AF. The balance between psychological factors and cardiac function in governing AF symptom severity has not been explored. Objectives: We aimed to analyse the severity of AF symptoms and of health-related quality of life in patients with preserved left ventricular (LV) systolic fucntionin the context of both psychological factors and of variables of left atrial (LA) and LV function. Methods: 84 participants with paroxysmal/persistent AF (n¼61) or longstanding/permanent AF (n¼23) and preserved LV systolic function completed the AF Symptom Severity Score (AFSS) and SF-36 Quality of Life questionnaires. Underlying personality type was assessed with the Perceived Stress Scale (PSS), Type D Personality Scale (TDPS) and Trait Anxiety Index (STAI-2). Anxiety and depression symptoms were assessed with the Beck Depression Index (BDI), the Hospital Anxiety and Depression Scale (HADS) and the State Anxiety Index (STAI-1). Baseline clinical factors were measured and a 2-D transthoracic echocardiogram performed for assessment of LV diastolic function and LA strain variables. Results: Younger age, paroxysmal AF, OSA and increased BMI predict more severe AF symptoms. Diabetes predicts less severe symptoms. No variable of LV diastolic function or LA strain is associated with AF symptom status. A personality tendency towards negative affectivity and social inhibition (TDPS), towards a tendency to perceive stress (PSS) and towards a chronic anxiety state (STAI-2) strongly predict more severe symptoms. The presence of anxiety and depression symptoms also strongly predicted more severe symptoms. The most powerful independent predictor of more severe AF symptoms on multivariate analysis was the presence of symptoms of depression. A poorer overall physical health status is predicted by hypertension, OSA, elevated BMI and enlarged LA area but not by any variable of LV diastolic dysfunction or LA strain. Again negative affectivity and social inhibition, higher perceived stress, higher levels of trait and state anxiety and more depression symptoms strongly predict poorer overall physical health status. Conclusion: In patients with AF and preserved LV systolic function underlying personality type and the presence of anxiety or depression symptoms rather than LV diastolic dysfunction or left atrial dysfunction predict more severe AF symptoms and poorer physical health status.
ABSTRACT The aim was to assess the incidence, presenting features, and complications of breastfee... more ABSTRACT The aim was to assess the incidence, presenting features, and complications of breastfeeding associated hypernatremic dehydration among hospitalized neonates. Materials and Methods: A retrospective study over a period of 18 months to identify term and near term (≥35 weeks of gestation) breastfed neonates, who were admitted with serum sodium concentration of ≥150 mEq/l and no apparent explanation for their hypernatremia other than inadequate breastmilk intake. Results: The incidence of breastfeeding associated hypernatremic dehydration among 2100 term and near term neonates was 1.38%. The median serum sodium at presentation was 164 mEq/l (range: 151-191 mEq/l). The mean weight loss in these patients was 10.16% ±6.6%. The reasons for seeking medical attention were refusal of feeds (72.41%), lethargy (68.96%), decreased urine output (44.82%), jaundice (27.58%) and fever (24.13%). Five patients (17.24%) had seizures and three (10.34%) had coagulopathy. Other complications included hypoglycemia, hypocalcemia, acute kidney injury (AKI) (37.93%) and intraventricular hemorrhage. The mean serum creatinine was 1.82 ± 2.5 mg/dl (range: 0.19-9.6). A statistically significant association was seen between serum sodium concentration at presentation and AKI. It was also found that those patients who had AKI had a higher weight loss and had presented later to the hospital than those without AKI. One patient died within 12 h of admission. This child had disseminated intravascular coagulopathy, AKI, and hypoglycemia. Conclusions: Breastfeeding associated hypernatremic dehydration is a serious condition with many serious complications and even results in death if detected late. Health care providers have increasing responsibilities of promoting proper breastfeeding techniques and taking measures for early diagnosis and treatment of this problem. Key words: Breastfeeding, hypernatremia,
Present study was conducted to determine the effects of honey on blood hemostasis, in-vitro effec... more Present study was conducted to determine the effects of honey on blood hemostasis, in-vitro effect of honey was observed on platelet aggregation and blood coagulation employing, activated partial prothrombin time (aPTT), prothrombin time (PT), thrombin time (TT) and fibrinogen levels in blood. Honey samples showed moderate inhibition of platelet aggregation with IC(50) 5-7.5%. The coagulation assays showed that at higher concentrations (>15%) honey samples increased whole blood clotting time. When assayed in platelet poor plasma (PPP), honey samples significantly (P>0.005) prolonged aPTT, PT, and TT. The honey samples (at 3.75% and 7.5% concentrations) cause mean increment of aPTT = 19±10% and 62±10%; PT 6±5% and 40±5%; TT 35±15% and 112±30% respectively. Moreover, PPP isolated from whole blood pre-incubated with honey samples (9.0% for 10 minutes) showed mean prolongation of aPTT, PT and TT of 45±21%, 26±9% and 105±24% respectively. Interestingly, incubation of honey at 6.25%...
The disruption of endothelial homeostasis and inflammation are fundamental to the initiation and ... more The disruption of endothelial homeostasis and inflammation are fundamental to the initiation and progression of atherosclerosis and preeclampsia (PE) [1-2]. PE is a pregnancy-specific multiorgan syndrome characterized by widespread endothelial damage with a clinical presentation of hypertension and proteinuria after 20 weeks of gestation [3]. It affects 3-8% of all pregnancies, with an incidence of 0.8% before 32 weeks [4]. The WHO reports over 60,000 maternal deaths worldwide per year as a consequence of eclampsia. Women with PE and their offspring are at an increased risk of developing cardiovascular disease later in life [5, 6]. Defective vasculogenesis in early placentation and resultant placental ischemia have been proposed to trigger the release of unknown mediators. Soluble anti-angiogenic factors in the maternal circulation precede the clinical PE and result in systemic maternal endothelial dysfunction [7-14]. We originally proposed that sFlt-1, an alternative mRNA splice variant of the fms-like tyrosin kinase gene (Flt-1) and antagonist of vascular endothelial growth factor (VEGF or VEGF-A), might be a key factor responsible for the clinical manifestation of PE because of a loss of circulating free VEGF [15]. Indeed, cancer patients receiving bevacizumab (Avastin ® , Roche; anti-VEGF therapy) exhibit PE-like symptoms (hypertension, proteinuria), suggesting that decreased bioavailability of VEGF causes these symptoms. Given the neurological findings in these patients, this is in line with recent observations that VEGF
Preeclampsia is a pregnancy-specific hypertensive syndrome that causes substantial maternal and f... more Preeclampsia is a pregnancy-specific hypertensive syndrome that causes substantial maternal and fetal morbidity and mortality. Recent evidence indicates that maternal endothelial dysfunction in preeclampsia results from increased soluble Fms-like tyrosine kinase-1 (sFlt-1), a circulating antiangiogenic protein. Factors responsible for excessive production of sFlt-1 in preeclampsia have not been identified. We tested the hypothesis that angiotensin II type 1 (AT 1 ) receptor activating autoantibodies, which occur in women with preeclampsia, contribute to increased production of sFlt-1. IgG from women with preeclampsia stimulates the synthesis and secretion of sFlt-1 via AT 1 receptor activation in pregnant mice, human placental villous explants, and human trophoblast cells. Using FK506 or short-interfering RNA targeted to the calcineurin catalytic subunit mRNA, we determined that calcineurin/nuclear factor of activated T-cells signaling functions downstream of the AT 1 receptor to in...
Angiopoietin-1 (Ang-1) is an angiogenic growth factor that activates Tie-2 and integrins to promo... more Angiopoietin-1 (Ang-1) is an angiogenic growth factor that activates Tie-2 and integrins to promote vessel wall remodeling. The recent finding of the potential proatherogenic effects of Ang-1 prompted us to investigate whether Ang-1 promotes monocyte chemotaxis, endothelial binding, and transendothelial migration, key events in the progression of atherosclerosis. Here, we show that Ang-1 induces chemotaxis of monocytes in a manner that is independent of Tie-2 and integrin binding but dependent on phosphoinositide 3-kinase and heparin. In addition, Ang-1 promoted phosphoinositide 3-kinase-dependent binding of monocytes to endothelial monolayers and stimulated transendothelial migration. Fluorescence-activated cell sorting analysis showed that exogenous Ang-1 adheres directly to monocytes as well as to human umbilical endothelial cells, but neither Tie-2 mRNA nor protein were expressed by primary monocytes. Although Ang-1 binding to human umbilical endothelial cells was partially Tie-...
Background: Carbon monoxide, the gaseous product of heme oxygenase, is a signalling molecule with... more Background: Carbon monoxide, the gaseous product of heme oxygenase, is a signalling molecule with a broad spectrum of biological activities. The aim of this study was to investigate the effects of carbon monoxide on proliferation of human pancreatic cancer. Methods: In vitro studies were performed on human pancreatic cancer cells (CAPAN-2, BxPc3, and PaTu-8902) treated with a carbon monoxide-releasing molecule or its inactive counterpart, or exposed to carbon monoxide gas (500 ppm/24 h). For in vivo studies, pancreatic cancer cells (CAPAN-2/PaTu-8902) were xenotransplanted subcutaneously into athymic mice, subsequently treated with carbon monoxidereleasing molecule (35 mg/kg b.w. i.p./day), or exposed to safe doses of carbon monoxide (500 ppm 1 h/day; n = 6 in each group). Results: Both carbon monoxide-releasing molecule and carbon monoxide exposure significantly inhibited proliferation of human pancreatic cancer cells (p < 0.05). A substantial decrease in Akt phosphorylation was observed in carbon monoxide-releasing molecule compared with inactive carbon monoxidereleasing molecule treated cancer cells (by 30-50%, p < 0.05). Simultaneously, carbon monoxide-releasing molecule and carbon monoxide exposure inhibited tumour proliferation and microvascular density of xenotransplanted tumours (p < 0.01), and doubled the survival rates (p < 0.005). Exposure of mice to carbon monoxide led to an almost 3-fold increase in carbon monoxide content in tumour tissues (p = 0.006). Conclusion: These data suggest a new biological function for carbon monoxide in carcinogenesis, and point to the potential chemotherapeutic/chemoadjuvant use of carbon monoxide in pancreatic cancer.
Ang-1 and Ang-2 are the best-characterized ligands of Tie-2 and were originally shown to be agoni... more Ang-1 and Ang-2 are the best-characterized ligands of Tie-2 and were originally shown to be agonistic and antagonistic, respectively [4-6]. Recent data showed that Ang-2 also acts as an agonist in a context-dependent manner [7], which will be discussed later. Ang-4 and the mouse orthologue of Ang-4, Ang-3, were identified later [8] and they function both as species-specific agonists and antagonists of Tie-2 [9]. The Tie-1 receptor has not been explored to the same extent as Tie-2.
Atherosclerosis is promoted by a combination of hypercholesterolemia and vascular inflammation. T... more Atherosclerosis is promoted by a combination of hypercholesterolemia and vascular inflammation. The function of Angiopoietin (Ang)-2, a key regulator of angiogenesis, in the maintenance of large vessels is unknown. A single systemic administration of Ang-2 adenovirus (AdAng-2) to apoE −/− mice fed a Western diet significantly reduced atherosclerotic lesion size (≈40%) and oxidized LDL and macrophage content of the plaques. These beneficial effects were abolished by the inhibition of nitric oxide synthase (NOS). In endothelial cells, endothelial NOS activation per se inhibited LDL oxidation and Ang-2 stimulated NO release in a Tie2-dependent manner to decrease LDL oxidation. These findings demonstrate a novel atheroprotective role for Ang-2 when endothelial cell function is compromised and suggest that growth factors, which stimulate NO release without inducing inflammation, could offer atheroprotection.
Biochemical and Biophysical Research Communications, 2006
Vascular endothelial growth factor-A (VEGF), which binds to both VEGF receptor-1 (Flt1) and VEGFR... more Vascular endothelial growth factor-A (VEGF), which binds to both VEGF receptor-1 (Flt1) and VEGFR-2 (KDR/Flk-1), requires nitric oxide (NO) to induce angiogenesis in a cGMP-dependent manner. Here we show that VEGF-E, a VEGFR-2-selective ligand stimulates NO release and tube formation in human umbilical vein endothelial cells (HUVEC). Inhibition of phospholipase Cc (PLCc) with U73122 abrogated VEGF-E induced endothelial cell migration, tube formation and NO release. Inhibition of endothelial nitric oxide synthase (eNOS) using L-NNA blocked VEGF-E-induced NO release and angiogenesis. Pre-incubation of HUVEC with the soluble guanylate cyclase inhibitor, ODQ, or the protein kinase G (PKG) inhibitor, KT-5823, had no effect on angiogenesis suggesting that the action of VEGF-E is cGMP-independent. Our data provide the first demonstration that VEGFR-2-mediated NO signaling and subsequent angiogenesis is through a mechanism that is dependent on PLCc but independent of cGMP and PKG.
conditions in myographs. Vascular segments were tested in the presence of the following inhibitor... more conditions in myographs. Vascular segments were tested in the presence of the following inhibitors: eNOS inhibitor L-NAME (100 μM), selective thromboxane receptor antagonist SQ 29,548 (1 μM), ceramidase inhibitor D-erythro-MAPP (50 μM), PI3-kinase inhibitor Wortmannin (0.1 μM), Akt-inhibitor MK2206 (1 μM), PLC inhibitor U73122 (10 μM) and cystathionine-γ-lyase (CSE) inhibitor propargylglycine (10 mM). We also tested the effects of sodium hydrosulfide (NaHS, 10 −5 − 10 −3 M) and sodium nitroprusside (SNP, 10 −10 − 10 −5 M) after precontraction induced by 1 μM phenylephrine in isometric condition in myographs. L-NAME administration completely abolished while SQ 29,548 increased relaxations in both groups, but especially in the db/db group. The use of D-erythro-MAPP, Wortmannin and MK2206 did not alter the vasoactive effects of SMase in control and db/db derived vessels, while U73122 completely inhibited the relaxations in diabetic aortas. The inhibition of H2S production led to less relaxation in db/db vessels but had no effect on control vessels. Dose-response curves for NaHS were shifted to the left while dose-response curves for SNP were shifted to the right in the db/db group. Our results indicate that H2S contributes to the SMase induced and surprisingly enhanced vasorelaxations in db/db animal derived aortas. The altered dose-response curves for NaHS and SNP suggest that phosphodiesterase activity might be enhanced in the aortas of db/db mice. This suggests decreased availability of its endogenous inhibitor H2S and indicates that sphingomyelinase might lead to enhanced vasorelaxations by massively increased NO production. An interesting aspect of our results is that diabetic vascular tissues have bigger sensitivity to either endogenously or exogenously altered H2S levels. Taken together our observations strengthen the importance to achieve proper H2S levels in diabetic vascular tissues.
Introduction: Vascular oxygen sensing has been attributed to hypoxic generation of reactive oxyge... more Introduction: Vascular oxygen sensing has been attributed to hypoxic generation of reactive oxygen species (ROS) which oxidize the cytosol and reduce the mitochondrial matrix (Waypa et al., 2010 [1]). However, H2S and polysulfides (H2Sn) have also been shown to affect redox status (Greiner et al., 2013 [2]). We hypothesize that reactive sulfur species (RSS) have the same effect on redox status as ROS and propose that this supports our hypothesis that the metabolism of H2S is the vascular oxygen sensor (Olson, 2015 [3]). Methods: In this study, we examined the effects of H2S (Na2S) and mixed H2Sn (K2Sn) on redox status of the redox sensitive green fluorescent protein (roGFP) purified from Escherichia coli (roGFP-E) using~40% and 100% oxidized protein incubated in either normoxia (21% O2) or anoxia (0% O2). We also examined the effects of H2S and H2Sn on roGFP inserted into either the cytoplasm (roGFP-C) or mitochondrial matrix (roGFP-M) of HEK-293 cells. Results: 1-300 μM H2S had no effect on roGFP-E whereas 40% oxidized roGFP-E was further oxidized by 1 mM H2S and completely oxidized by H2S >1 mM in both 21 and 0% O2. H2Sn oxidized roGFP-E at considerably lower concentrations (>3 μM) and independently of O2 availability. We saw no evidence for roGFP-E reduction by either H2S or H2Sn. Conversely, 10 μM H2S and above oxidized roGFP-C and reduced roGFP-M in-vitro; H2Sn reduced roGFP-C and roGFP-M at concentrations <1 mM and oxidized them at concentrations >1 mM. Conclusions: 1. H2S is not an efficient reductant, particularly in cells. 2. The time course of H2S activation is inconsistent with a preexisting polysulfide contaminant, but because H2S cannot be an oxidant, we conclude that H2S must somehow react with roGFP-E to produce an oxidant, probably a polysulfide. 3. The oxidizing ability of H2S is O2-independent. 4. The increased efficacy of H2S compared to H2Sn in HEK-293 cells may be due to rapid permeation of H2S. 5. The effects of hypoxia on intracellular redox status is mimicked by exogenous H2S, providing additional support to our hypothesis of H2S metabolism as the O2 sensor.
Introduction: The influence of psychological factors on the patient experience of AF has been dem... more Introduction: The influence of psychological factors on the patient experience of AF has been demonstrated to be in excess of the objective burden of AF. The balance between psychological factors and cardiac function in governing AF symptom severity has not been explored. Objectives: We aimed to analyse the severity of AF symptoms and of health-related quality of life in patients with preserved left ventricular (LV) systolic fucntionin the context of both psychological factors and of variables of left atrial (LA) and LV function. Methods: 84 participants with paroxysmal/persistent AF (n¼61) or longstanding/permanent AF (n¼23) and preserved LV systolic function completed the AF Symptom Severity Score (AFSS) and SF-36 Quality of Life questionnaires. Underlying personality type was assessed with the Perceived Stress Scale (PSS), Type D Personality Scale (TDPS) and Trait Anxiety Index (STAI-2). Anxiety and depression symptoms were assessed with the Beck Depression Index (BDI), the Hospital Anxiety and Depression Scale (HADS) and the State Anxiety Index (STAI-1). Baseline clinical factors were measured and a 2-D transthoracic echocardiogram performed for assessment of LV diastolic function and LA strain variables. Results: Younger age, paroxysmal AF, OSA and increased BMI predict more severe AF symptoms. Diabetes predicts less severe symptoms. No variable of LV diastolic function or LA strain is associated with AF symptom status. A personality tendency towards negative affectivity and social inhibition (TDPS), towards a tendency to perceive stress (PSS) and towards a chronic anxiety state (STAI-2) strongly predict more severe symptoms. The presence of anxiety and depression symptoms also strongly predicted more severe symptoms. The most powerful independent predictor of more severe AF symptoms on multivariate analysis was the presence of symptoms of depression. A poorer overall physical health status is predicted by hypertension, OSA, elevated BMI and enlarged LA area but not by any variable of LV diastolic dysfunction or LA strain. Again negative affectivity and social inhibition, higher perceived stress, higher levels of trait and state anxiety and more depression symptoms strongly predict poorer overall physical health status. Conclusion: In patients with AF and preserved LV systolic function underlying personality type and the presence of anxiety or depression symptoms rather than LV diastolic dysfunction or left atrial dysfunction predict more severe AF symptoms and poorer physical health status.
ABSTRACT The aim was to assess the incidence, presenting features, and complications of breastfee... more ABSTRACT The aim was to assess the incidence, presenting features, and complications of breastfeeding associated hypernatremic dehydration among hospitalized neonates. Materials and Methods: A retrospective study over a period of 18 months to identify term and near term (≥35 weeks of gestation) breastfed neonates, who were admitted with serum sodium concentration of ≥150 mEq/l and no apparent explanation for their hypernatremia other than inadequate breastmilk intake. Results: The incidence of breastfeeding associated hypernatremic dehydration among 2100 term and near term neonates was 1.38%. The median serum sodium at presentation was 164 mEq/l (range: 151-191 mEq/l). The mean weight loss in these patients was 10.16% ±6.6%. The reasons for seeking medical attention were refusal of feeds (72.41%), lethargy (68.96%), decreased urine output (44.82%), jaundice (27.58%) and fever (24.13%). Five patients (17.24%) had seizures and three (10.34%) had coagulopathy. Other complications included hypoglycemia, hypocalcemia, acute kidney injury (AKI) (37.93%) and intraventricular hemorrhage. The mean serum creatinine was 1.82 ± 2.5 mg/dl (range: 0.19-9.6). A statistically significant association was seen between serum sodium concentration at presentation and AKI. It was also found that those patients who had AKI had a higher weight loss and had presented later to the hospital than those without AKI. One patient died within 12 h of admission. This child had disseminated intravascular coagulopathy, AKI, and hypoglycemia. Conclusions: Breastfeeding associated hypernatremic dehydration is a serious condition with many serious complications and even results in death if detected late. Health care providers have increasing responsibilities of promoting proper breastfeeding techniques and taking measures for early diagnosis and treatment of this problem. Key words: Breastfeeding, hypernatremia,
Present study was conducted to determine the effects of honey on blood hemostasis, in-vitro effec... more Present study was conducted to determine the effects of honey on blood hemostasis, in-vitro effect of honey was observed on platelet aggregation and blood coagulation employing, activated partial prothrombin time (aPTT), prothrombin time (PT), thrombin time (TT) and fibrinogen levels in blood. Honey samples showed moderate inhibition of platelet aggregation with IC(50) 5-7.5%. The coagulation assays showed that at higher concentrations (>15%) honey samples increased whole blood clotting time. When assayed in platelet poor plasma (PPP), honey samples significantly (P>0.005) prolonged aPTT, PT, and TT. The honey samples (at 3.75% and 7.5% concentrations) cause mean increment of aPTT = 19±10% and 62±10%; PT 6±5% and 40±5%; TT 35±15% and 112±30% respectively. Moreover, PPP isolated from whole blood pre-incubated with honey samples (9.0% for 10 minutes) showed mean prolongation of aPTT, PT and TT of 45±21%, 26±9% and 105±24% respectively. Interestingly, incubation of honey at 6.25%...
The disruption of endothelial homeostasis and inflammation are fundamental to the initiation and ... more The disruption of endothelial homeostasis and inflammation are fundamental to the initiation and progression of atherosclerosis and preeclampsia (PE) [1-2]. PE is a pregnancy-specific multiorgan syndrome characterized by widespread endothelial damage with a clinical presentation of hypertension and proteinuria after 20 weeks of gestation [3]. It affects 3-8% of all pregnancies, with an incidence of 0.8% before 32 weeks [4]. The WHO reports over 60,000 maternal deaths worldwide per year as a consequence of eclampsia. Women with PE and their offspring are at an increased risk of developing cardiovascular disease later in life [5, 6]. Defective vasculogenesis in early placentation and resultant placental ischemia have been proposed to trigger the release of unknown mediators. Soluble anti-angiogenic factors in the maternal circulation precede the clinical PE and result in systemic maternal endothelial dysfunction [7-14]. We originally proposed that sFlt-1, an alternative mRNA splice variant of the fms-like tyrosin kinase gene (Flt-1) and antagonist of vascular endothelial growth factor (VEGF or VEGF-A), might be a key factor responsible for the clinical manifestation of PE because of a loss of circulating free VEGF [15]. Indeed, cancer patients receiving bevacizumab (Avastin ® , Roche; anti-VEGF therapy) exhibit PE-like symptoms (hypertension, proteinuria), suggesting that decreased bioavailability of VEGF causes these symptoms. Given the neurological findings in these patients, this is in line with recent observations that VEGF
Preeclampsia is a pregnancy-specific hypertensive syndrome that causes substantial maternal and f... more Preeclampsia is a pregnancy-specific hypertensive syndrome that causes substantial maternal and fetal morbidity and mortality. Recent evidence indicates that maternal endothelial dysfunction in preeclampsia results from increased soluble Fms-like tyrosine kinase-1 (sFlt-1), a circulating antiangiogenic protein. Factors responsible for excessive production of sFlt-1 in preeclampsia have not been identified. We tested the hypothesis that angiotensin II type 1 (AT 1 ) receptor activating autoantibodies, which occur in women with preeclampsia, contribute to increased production of sFlt-1. IgG from women with preeclampsia stimulates the synthesis and secretion of sFlt-1 via AT 1 receptor activation in pregnant mice, human placental villous explants, and human trophoblast cells. Using FK506 or short-interfering RNA targeted to the calcineurin catalytic subunit mRNA, we determined that calcineurin/nuclear factor of activated T-cells signaling functions downstream of the AT 1 receptor to in...
Angiopoietin-1 (Ang-1) is an angiogenic growth factor that activates Tie-2 and integrins to promo... more Angiopoietin-1 (Ang-1) is an angiogenic growth factor that activates Tie-2 and integrins to promote vessel wall remodeling. The recent finding of the potential proatherogenic effects of Ang-1 prompted us to investigate whether Ang-1 promotes monocyte chemotaxis, endothelial binding, and transendothelial migration, key events in the progression of atherosclerosis. Here, we show that Ang-1 induces chemotaxis of monocytes in a manner that is independent of Tie-2 and integrin binding but dependent on phosphoinositide 3-kinase and heparin. In addition, Ang-1 promoted phosphoinositide 3-kinase-dependent binding of monocytes to endothelial monolayers and stimulated transendothelial migration. Fluorescence-activated cell sorting analysis showed that exogenous Ang-1 adheres directly to monocytes as well as to human umbilical endothelial cells, but neither Tie-2 mRNA nor protein were expressed by primary monocytes. Although Ang-1 binding to human umbilical endothelial cells was partially Tie-...
Background: Carbon monoxide, the gaseous product of heme oxygenase, is a signalling molecule with... more Background: Carbon monoxide, the gaseous product of heme oxygenase, is a signalling molecule with a broad spectrum of biological activities. The aim of this study was to investigate the effects of carbon monoxide on proliferation of human pancreatic cancer. Methods: In vitro studies were performed on human pancreatic cancer cells (CAPAN-2, BxPc3, and PaTu-8902) treated with a carbon monoxide-releasing molecule or its inactive counterpart, or exposed to carbon monoxide gas (500 ppm/24 h). For in vivo studies, pancreatic cancer cells (CAPAN-2/PaTu-8902) were xenotransplanted subcutaneously into athymic mice, subsequently treated with carbon monoxidereleasing molecule (35 mg/kg b.w. i.p./day), or exposed to safe doses of carbon monoxide (500 ppm 1 h/day; n = 6 in each group). Results: Both carbon monoxide-releasing molecule and carbon monoxide exposure significantly inhibited proliferation of human pancreatic cancer cells (p < 0.05). A substantial decrease in Akt phosphorylation was observed in carbon monoxide-releasing molecule compared with inactive carbon monoxidereleasing molecule treated cancer cells (by 30-50%, p < 0.05). Simultaneously, carbon monoxide-releasing molecule and carbon monoxide exposure inhibited tumour proliferation and microvascular density of xenotransplanted tumours (p < 0.01), and doubled the survival rates (p < 0.005). Exposure of mice to carbon monoxide led to an almost 3-fold increase in carbon monoxide content in tumour tissues (p = 0.006). Conclusion: These data suggest a new biological function for carbon monoxide in carcinogenesis, and point to the potential chemotherapeutic/chemoadjuvant use of carbon monoxide in pancreatic cancer.
Ang-1 and Ang-2 are the best-characterized ligands of Tie-2 and were originally shown to be agoni... more Ang-1 and Ang-2 are the best-characterized ligands of Tie-2 and were originally shown to be agonistic and antagonistic, respectively [4-6]. Recent data showed that Ang-2 also acts as an agonist in a context-dependent manner [7], which will be discussed later. Ang-4 and the mouse orthologue of Ang-4, Ang-3, were identified later [8] and they function both as species-specific agonists and antagonists of Tie-2 [9]. The Tie-1 receptor has not been explored to the same extent as Tie-2.
Atherosclerosis is promoted by a combination of hypercholesterolemia and vascular inflammation. T... more Atherosclerosis is promoted by a combination of hypercholesterolemia and vascular inflammation. The function of Angiopoietin (Ang)-2, a key regulator of angiogenesis, in the maintenance of large vessels is unknown. A single systemic administration of Ang-2 adenovirus (AdAng-2) to apoE −/− mice fed a Western diet significantly reduced atherosclerotic lesion size (≈40%) and oxidized LDL and macrophage content of the plaques. These beneficial effects were abolished by the inhibition of nitric oxide synthase (NOS). In endothelial cells, endothelial NOS activation per se inhibited LDL oxidation and Ang-2 stimulated NO release in a Tie2-dependent manner to decrease LDL oxidation. These findings demonstrate a novel atheroprotective role for Ang-2 when endothelial cell function is compromised and suggest that growth factors, which stimulate NO release without inducing inflammation, could offer atheroprotection.
Biochemical and Biophysical Research Communications, 2006
Vascular endothelial growth factor-A (VEGF), which binds to both VEGF receptor-1 (Flt1) and VEGFR... more Vascular endothelial growth factor-A (VEGF), which binds to both VEGF receptor-1 (Flt1) and VEGFR-2 (KDR/Flk-1), requires nitric oxide (NO) to induce angiogenesis in a cGMP-dependent manner. Here we show that VEGF-E, a VEGFR-2-selective ligand stimulates NO release and tube formation in human umbilical vein endothelial cells (HUVEC). Inhibition of phospholipase Cc (PLCc) with U73122 abrogated VEGF-E induced endothelial cell migration, tube formation and NO release. Inhibition of endothelial nitric oxide synthase (eNOS) using L-NNA blocked VEGF-E-induced NO release and angiogenesis. Pre-incubation of HUVEC with the soluble guanylate cyclase inhibitor, ODQ, or the protein kinase G (PKG) inhibitor, KT-5823, had no effect on angiogenesis suggesting that the action of VEGF-E is cGMP-independent. Our data provide the first demonstration that VEGFR-2-mediated NO signaling and subsequent angiogenesis is through a mechanism that is dependent on PLCc but independent of cGMP and PKG.
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Papers by Asif Ahmed