Nitric oxide insufficiency and atherothrombosis

Effects of angiotensin converting enzyme inhibitor and angiotensin II receptor antagonist combination on nitric oxide bioavailability and atherosclerotic change in Watanabe heritable hyperlipidemic rabbits

We investigated the effects of co-administration of an angiotensin-converting enzyme inhibitor (ACEI) and angiotensin type 1 receptor blocker (ARB) on nitric oxide (NO) bioavailability in genetically hyperlipidemic rabbits with our newly developed NO sensor. Plasma NO was measured using the new NO sensor in the abdominal aorta of anesthetized Watanabe heritable hyperlipidemic (WHHL) rabbits. Acetylcholine (ACh)-stimulated (20 microg in 5 min into the aortic arch) NO production was recorded after an 8 week per os pretreatment with 1) vehicle (control), 2) the ACEI enalapril (E: 3 mg/kg/day), 3) the ARB losartan (L: 30 mg/kg/day) and 4) enalapril (1.5 mg/kg/day)+losartan (15 mg/kg/day) (E+L). Intra-aortic infusion of ACh produced an increase in plasma NO concentration, which was significantly greater with all the drug treatments than with the control. E increased ACh-induced NO significantly more than L (by 6.9 nmol/L, and 4.7 nmol/L, respectively). E+L increased ACh-induced NO by 9.5 nmol/L, significantly more than either E or L. Plasma peroxynitrite concentration was 1.2 pmol/mg protein in the control group and significantly less than in the E- and L-group. The lowest peroxynitrite concentration was observed in the E+L group (0.5 pmol/mg protein), which was significantly lower than in the E-group and the L-group. Optical coherence tomography and histology of the thoracic aorta revealed that the plaque area decreased significantly more with the combination than with the monotherapy (p<0.01). In conclusion, the combined treatment with an ACEI and an ARB may have additive protective effects on endothelial function as well as atherosclerotic change.

Supplementation with orange and blackcurrant juice, but not vitamin E, improves inflammatory markers in patients with peripheral arterial disease

Inflammation and endothelial activation are associated with an increased risk of CVD and epidemiological evidence suggests an association between levels of markers of inflammation or endothelial activation and the intake of fruit. Also, vitamin E, a fat-soluble antioxidant, has anti-inflammatory properties. We performed a randomised 2 × 2 factorial, crossover trial to determine the effect of orange and blackcurrant juice (500 ml/d) and vitamin E (15 mg RRR-α-tocopherol/d) supplementation on markers of inflammation and endothelial activation in forty-eight patients with peripheral arterial disease. Patients were randomly allocated to two dietary supplements from the four possible combinations of juice and vitamin E: juice+vitamin E; juice+placebo; reference beverage (sugar drink)+vitamin E; and reference beverage+placebo. The supplementations were given for 28 d, separated by a 4-week wash-out period. Analysis of main effects showed that juice decreased C-reactive protein (CRP) by 11 % and fibrinogen by 3 % while the reference drink increased CRP by 13 % and fibrinogen by 2 % (P < 0·008 and P < 0·002, respectively). No significant differences were measured for IL-6 and the endothelial activation markers von Willebrand factor, tissue-plasminogen activator and plasmin activator inhibitor-1. Vitamin E supplementation had no significant effects on the various markers. We observed no significant interaction between juice and vitamin E. In this study, orange and blackcurrant juice reduced markers of inflammation, but not markers of endothelial activation, in patients with peripheral arterial disease, relative to sugar drinks.

In vivo wall shear stress measurements using phase-contrast MRI

There is growing evidence to suggest that endothelial biology and atherosclerosis depend on arterial wall shear stress (WSS). We review the existing literature on in vivo measurements of WSS in healthy individuals using phase-contrast MRI, which is a promising, noninvasive technique for determining various blood flow characteristics. WSS data exist for the following arteries: carotid, brachial, aorta and femoral. Measured values indicate that WSS is site specific, a finding which opposes the notion that physiological WSS values are maintained at a constant magnitude in all parts of the arterial system. Among the WSS values obtained at the same site by different investigators there is qualitative agreement; however, differences exist in absolute values mainly due to the dependence on the method used to obtain WSS values from velocity data.

Recent progress in histochemistry

The progress in discerning the structure and function of cells and tissues in health and disease has been achieved to a large extent by the continued development of new reagents for histochemistry, the improvement of existing techniques and new imaging techniques. This review will highlight some advancements made in these fields.

CYBA C242T gene polymorphism and flow-mediated vasodilation in a population of young adults: the Cardiovascular Risk in Young Finns Study

OBJECTIVE

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is a major source of the superoxide anion that contributes to decreased nitric oxide bioavailability in the vasculature. The C242T polymorphism of the CYBA gene that encodes p22phox, a component of NADPH oxidase, has been found to modulate superoxide production. We examined the relationship of the C242T polymorphism with endothelial-dependent brachial artery flow-mediated vasodilatation (FMD) in a population-based sample of young healthy adults.

METHODS

FMD, defined as the increased percentage in brachial artery diameter after reactive hyperemia, was assessed by ultrasound and the C242T polymorphism using a 5' nuclease assay in 2058 subjects aged 24-39 years.

RESULTS

The mean values of brachial artery FMD were 8.0 +/- 4.4% in all study subjects (n = 2058), and 7.8 +/- 4.4, 8.2 +/- 4.5, and 8.7 +/- 4.5% in subjects with the CC (n = 1362), CT (n = 616), and TT (n = 80) genotypes of the C242T CYBA polymorphism, respectively (P = 0.02 for trend). The association remained significant (P = 0.019) in multivariate analyses adjusted for age, sex, obesity indices, smoking habits, blood pressure, serum glucose, lipids, and C-reactive protein. The relationship between FMD and the C242T polymorphism was stronger (P = 0.004) in overweight subjects (body mass index > or = 25 kg/m, n = 895) and ever-smokers (P = 0.008, n = 1082), whereas no relationship was found in normal-weight subjects and non-smokers (P = 0.824 and P = 0.438, respectively).

CONCLUSION

The C242T polymorphism of the CYBA gene seems to be related to endothelial function in a population-based sample of young healthy adults. Overweight and smoking status may modify this genetic effect.

The effects of long-term smoking on endothelial nitric oxide synthase mRNA expression in human platelets as detected with real-time quantitative RT-PCR

Endothelium-derived nitric oxide (NO) plays an important role in the prevention of platelet aggregation and adhesion to the vascular wall. Endothelial nitric oxide synthase (eNOS) and L-arginine/NO pathway are both present in human platelets. Platelet-derived NO inhibits excessive activation and aggregation of platelets. However, the expression level of the eNOS gene in human platelets has yet to be elucidated. The current study investigates the individual expression level of platelet eNOS mRNA using the real-time reverse transcriptase-polymerase chain reaction (RT-PCR) detection method. eNOS mRNA expression was examined in platelets isolated from 50 subjects: 11 male smokers, 15 male nonsmokers, and 24 female non-smokers. After extraction of platelet total RNA, eNOS (target) and GAPDH (internal control) mRNA expression levels were quantitated using real-time RT-PCR. The expression levels of eNOS mRNA (relative copy numbers) were significantly lower in male smokers (59+/-17) than in male nonsmokers (195+/-71, P < .03), and higher in female nonsmokers (285+/-60) than in the male nonsmokers (195+/-71, P < .03). By multiple linear regression analysis, cigarette smoking (P = .008) and diabetes mellitus (P = .047) were found to be significantly negative predictors, and antioxidant (vitamin E) treatment (P = .01) was a significantly positive predictor of platelet eNOS mRNA expression. Age, other medications, and other risk factors for coronary artery disease were not significant. Using this method, eNOS mRNA abundance in human platelets was detected and quantitated in real-time. The intraplatelet eNOS mRNA expression levels were significantly decreased in cigarette smokers. Low platelet NO synthesis in smokers may result in the augmentation of platelet aggregation and thrombus formation, developing into acute coronary syndromes.

NCX 6560, a nitric oxide-releasing derivative of atorvastatin, inhibits cholesterol biosynthesis and shows anti-inflammatory and anti-thrombotic properties

We compared the lipid-lowering, vasodilating, anti-thrombotic and anti-inflammatory properties of NCX 6560, a novel NO-releasing derivative of atorvastatin, with those of atorvastatin. NCX 6560 and atorvastatin induced similar inhibition of cholesterol biosynthesis in rat smooth muscle cells (IC(50)=1.9+/-0.4 and 3.9+/-1.0 microM, respectively). However, in hyperlipidemic mice, a 5-week oral treatment with NCX 6560 (46.8 mg/kg/day, p.o.) was more effective than equivalent atorvastatin (40 mg/kg/day, p.o.) at lowering serum cholesterol (NCX 6560: -21% vs controls, P<0.05; atorvastatin: -14% vs control, P=NS). In norepinephrine-precontracted rabbit aortic rings, NCX 6560-induced vasodilation (EC(50)=53.5+/-8.3 microM) and in PC12 cells it stimulated cGMP formation (EC(50)=1.8+/-0.7 microM), while atorvastatin was inactive. In lipopolysaccharide from Escherichia coli (LPS)-treated RAW 264.7 macrophages, NCX 6560 reduced iNOS expression and dimer assembly more efficiently than atorvastatin and inhibited nitrite accumulation (IC(50)=6.7+/-1.6 microM) and TNFalpha release. U46619- or collagen plus epinephrine-induced platelet pulmonary thromboembolism in mice was reduced by NCX 6560 at 46.8 mg/kg p.o. (mortality: -44% and -56% vs vehicle, respectively; P<0.05), but not by atorvastatin 40 mg/kg, p.o. In the U46619-induced mortality model, isosorbide mononitrate (ISMN) (20 mg/kg, p.o.), a pure NO-donor, was also active (mortality: -40%, P<0.05). NCX 6560 significantly reduced ex vivo platelet adhesion to collagen at high shear (-31+/-1.3% vs vehicle), and so did ISMN (-33.3+/-1.7% vs vehicle). Atorvastatin was ineffective. NCX 6560, but not atorvastatin, reduced blood pressure in eNOS knockout mice (-16%, P<0.001 vs vehicle), an effect not observed in wild type mice. On the contrary, ISMN provoked a significant drop of blood pressure both in wild type (-20%, P<0.05 vs vehicle) and in eNOS-/- mice (-21%, P<0.05 vs vehicle). In conclusion, NCX 6560 exerts greater lipid-lowering, anti-thrombotic and anti-inflammatory effects than atorvastatin, due to a large extent to NO release.

Meal amino acids with varied levels of arginine do not affect postprandial vascular endothelial function in healthy young men

Postprandial endothelial dysfunction is a key event mediating the effects of diet on early atherogenesis. The potential effects of protein intake have been overlooked in the past, although amino acids are precursors for homocysteine and nitric oxide (NO). Our objective was to study the effect of amino acids on postprandial vascular function, in relation to the utilization of meal arginine for NO production. In a crossover design, 9 men ingested 50 g of a complete amino acid mixture, trace-labeled with (13)C-glycine and (15)N(2)-arginine, without (meal A) or with (meal B) 3 g extra arginine. The postprandial utilization of meal arginine for NO production was determined from urinary (15)NO(3). We monitored endothelial function of the brachial artery, the stiffness of the common carotid artery, aortic pulse wave velocity and soluble markers related to endothelial function for 8 h. Meal A did not significantly increase plasma homocysteine and did not alter endothelial function markers. The amount of NO synthesized from meal arginine doubled after meal B (107.1 +/- 16.5% increase vs. meal A, P < 0.01) but was very low (271 +/- 84 ppm vs. 332 +/- 73 ppm, P < 0.05, respectively). After meal B, flow-mediated and nitroglycerine-induced dilation decreased but common carotid artery compliance, pulse wave velocity, plasma soluble intercellular adhesion molecule-1, and von Willebrand factor, and urinary cGMP did not differ when compared with meal A. Together, the data indicate that, in healthy men, meal amino acids do not adversely affect endothelial function, and meal arginine only slightly enters the NO pathway. Unexpectedly, arginine in physiological amounts may acutely lessen smooth muscle cell reactivity to a high dynamic NO release.

Anti-thrombotic effect of chronic oral treatment with Orbignya phalerata Mart

Babassu is the popular name of Orbignya phalerata Mart. (Arecaceae). The mesocarp flour obtained from their fruits has been used in Brazil as medicine in the treatment of pains, constipation, obesity, leukemia, rheumatism, ulcerations, tumors, inflammations and venous diseases. The effect of the chronic oral treatment with aqueous extract of babassu mesocarp (500mg/kgday) on the number of platelets, the prothrombin time (PT), the activated partial thromboplastin time (aPTT), the nitric oxide (NO) production and the carrageenin-induced thrombosis was evaluated, using C57Bl/6 mice. The chronic oral treatment with babassu mesocarp induced an anti-thrombotic effect. There was a 88.9% reduction in the necrosis of the tail. This effect seems to be related to an increase in the ability of the macrophage to produce NO and to a slow coagulation process associated to an increase of 12.0 and 13.9% in PT and aPTT, respectively. However, the anti-thrombotic effect seems to be not related to alterations in the number of platelets. It is possible to conclude that the oral treatment with babassu mesocarp has a significant anti-thrombotic effect, which could justify the popular use of babassu mesocarp in the treatment of venous diseases. Meanwhile, this study suggests a potential use of babassu mesocarp as a prophylactic agent to avoid thrombosis events.

Real-time imaging of nitric oxide production in living cells with 1,3,5,7-tetramethyl-2,6-dicarbethoxy-8-(3′,4′-diaminophenyl)-difluoroboradiaza-s-indacence by invert fluorescence microscope

Although the importance of nitric oxide (NO) as a signalling molecule in many biological processes is becoming increasingly evident, many proposed and potential biological functions of NO still remain unclear. Bioimaging is a good technique to visualize observation of nitric oxide in biological samples. In this report, a fluorescent probe, 1,3,5,7-tetramethyl-2,6-dicarbethoxy-8-(3',4'-diaminophenyl)-difluoroboradiaza-s-indacence (TMDCDABODIPY), has been first applied to real-time image NO produced in PC12 cells, Sf9 cells and human vascular endothelial cells at the presence of l-arginine with inverted fluorescence microscope. NO production in the cells is successfully captured and imaged with fine temporal and spatial resolution. The results prove that the probe combined with inverted fluorescence microscope can be developed into a sensitive and selective method for further study of NO release from cells.

Detection of human CYP2C8, CYP2C9, and CYP2J2 in cardiovascular tissues

The cytochrome P450 (P450) enzymes CYP2C8, CYP2C9, and CYP2J2 metabolize arachidonic acid to epoxyeicosatrienoic acids, which are known to be vital in regulation of vascular tone and cardiovascular homeostasis. Because there is limited information regarding the relative expression of these P450 enzymes in cardiovascular tissues, this study examined the expression of CYP2C8, CYP2C9, and CYP2J2 mRNA and protein in human heart, aorta, and coronary artery samples by real-time polymerase chain reaction, immunoblotting, and immunohistochemistry. CYP2J2 and CYP2C9 mRNA levels were highly variable in human hearts, whereas CYP2C8 mRNA was present in lower abundance. CYP2J2 mRNA was approximately 10(3) times higher than CYP2C9 or CYP2C8 in human heart. However, CYP2C9 mRNA was more abundant than CYP2J2 or CYP2C8 in one ischemic heart. In human aorta, mean CYP2C9 mRNA levels were approximately 50 times higher than that of CYP2J2 and 5-fold higher than that of CYP2C8. In human coronary artery, mean values for CYP2C9 mRNA were approximately 2-fold higher than that of CYP2J2 mRNA and 6-fold higher than that of CYP2C8 mRNA. Immunoblotting results show relatively high levels of CYP2J2 and CYP2C8 protein in human hearts, which was confirmed by immunohistochemistry. CYP2C9 protein was also detected at high levels in one ischemic heart by immunoblotting. CYP2C9 was present at higher levels than CYPJ2 in aorta and coronary artery, whereas CYP2C8 protein was below the limits of detection. The expression of CYP2J2 and CYP2C8 in human heart, and CYPC9 and CYP2J2 in aorta and coronary artery is consistent with a physiological role for these enzymes in these tissues.

Effects of Angiotensin II on NO Bioavailability Evaluated Using a Catheter-Type NO Sensor

We investigated the acute or chronic effects of angiotensin (Ang) II on the bioavailability of NO in Ang II-infused rabbits using the catheter-type NO sensor. Male New Zealand White rabbits were infused with vehicle (sham), Ang II at a rate of 200 ng/kg per minute, either alone or in combination with hydralazine, Ang II type I receptor antagonist (valsartan), or an antioxidant (tempol) for 24 hours or 14 days. Plasma NO concentration was measured using the catheter-type NO sensor located in the aorta. We then infused saline (vehicle) and acetylcholine (ACh) into the aortic arch with or without pretreatment with N(G)-methyl-l-arginine. An increase in plasma NO levels in response to ACh was significantly attenuated in the Ang II group compared wit the control group. The decrease in the basal plasma NO concentration was significantly lower in the Ang II group than in the control group. Plasma peroxynitrite concentrations in Ang II group were significantly higher than in the control group. The negative effects of Ang II, that is, the decrease in basal and ACh-induced NO production and the increase in oxidative stress, were significantly suppressed by the cotreatment with either valsartan or tempol. Short-term treatment with Ang II significantly increased the ACh-induced increase in plasma NO concentration, as well as basal NO release. Although Ang II stimulates release of NO in the short term, chronic treatment with Ang II elicits the decreased NO bioavailability in the aorta of the Ang II-infusion rabbit model.

The histochemistry and cell biology vade mecum: a review of 2005–2006

The procurement of new knowledge and understanding in the ever expanding discipline of cell biology continues to advance at a breakneck pace. The progress in discerning the physiology of cells and tissues in health and disease has been driven to a large extent by the continued development of new probes and imaging techniques. The recent introduction of semi-conductor quantum dots as stable, specific markers for both fluorescence light microscopy and electron microscopy, as well as a virtual treasure-trove of new fluorescent proteins, has in conjunction with newly introduced spectral imaging systems, opened vistas into the seemingly unlimited possibilities for experimental design. Although it oftentimes proves difficult to predict what the future will hold with respect to advances in disciplines such as cell biology and histochemistry, it is facile to look back on what has already occurred. In this spirit, this review will highlight some advancements made in these areas in the past 2 years.

Cerebrovascular disease associated with sickle cell pulmonary hypertension

In patients with sickle cell disease, anemia is a recognized risk factor for stroke, death, and the development of pulmonary hypertension. We have proposed that hemolytic anemia results in endothelial dysfunction and vascular instability and can ultimately lead to a proliferative vasculopathy leading to pulmonary hypertension. Consistent with this mechanism of disease, we now report a case series of six patients with obliterative central nervous system vasculopathy who also have pulmonary hypertension and high hemolytic rate. These patients, identified in the course of a prospective screening study for pulmonary hypertension, presented with neurological symptoms prompting neuroimaging studies. Compared to 164 other patients of similar age in the screened population, those with newly diagnosed or clinically active cerebrovascular disease have significantly lower hemoglobin levels and higher levels of lactate dehydrogenase. A review of the literature suggests that many clinical, epidemiological, and physiological features of the arteriopathy of pulmonary hypertension closely overlap with those of stroke in sickle cell disease, both known to involve proliferative vascular intimal and smooth muscle hypertrophy and thrombosis. These cases suggest that cerebrovascular disease and pulmonary hypertension in sickle cell disease share common mechanisms, in particular, reduced nitric oxide bioactivity associated with particularly high-grade hemolysis. Clinicians should suspect occult cerebrovascular disease in sickle cell patients with pulmonary hypertension.

Emerging role of epoxyeicosatrienoic acids in coronary vascular function

The importance of endothelium-derived nitric oxide in coronary vascular regulation is well-established and the loss of this vasodilator compound is associated with endothelial dysfunction, tissue hypoperfusion and atherosclerosis. Numerous studies indicate that the endothelium produces another class of compounds, the epoxyeicosatrienoic acids (EETs), which may partially compensate for the loss of nitric oxide in cardiovascular disease. The EETs are endogenous lipids which are derived through the metabolism of arachidonic acid by cytochrome P450 epoxygenase enzymes. Also, EETs hyperpolarize vascular smooth muscle and induce dilation of coronary arteries and arterioles, and therefore may be endogenous mediators of coronary vasomotor tone and myocardial perfusion. In addition, EETs have been shown to inhibit vascular smooth muscle migration, decrease inflammation, inhibit platelet aggregation and decrease adhesion molecule expression, therefore representing an endogenous protective mechanism against atherosclerosis. Endogenous EETs are degraded to less active dihydroxyeicosatrienoic acids by soluble epoxide hydrolase. Pharmacological inhibition of soluble epoxide hydrolase has received considerable attention as a potential approach to enhance EET-mediated vascular protection, and several compounds have appeared promising in recent animal studies. The present review discusses the emerging role of EETs in coronary vascular function, as well as recent advancements in the development of pharmacological agents to enhance EET bioavailability.

Sickle cell disease and nitric oxide: a paradigm shift?

Traditionally the pathophysiology of sickle cell disease is thought to result from the polymerization of hemoglobin S in red cells, under hypoxic conditions, resulting in the occlusion of blood vessels. Adhesion of cells to the venular endothelium also appears to play a role. Recent studies have also suggested that in addition to the polymerization of hemoglobin S in the red blood cell, a deficiency of the endogenous vasodilator, nitric oxide may be involved. Hemoglobin released as a result of hemolysis rapidly consumes nitric oxide resulting in a whole program of events that inhibit blood flow. Therapies directed at decreasing the destruction of nitric oxide, increasing the production of nitric oxide, or amplifying the nitric oxide response may prove beneficial.

Atherothrombosis and high-risk plaque: part I: evolving concepts

Atherothrombosis is a complex disease in which cholesterol deposition, inflammation, and thrombus formation play a major role. Rupture of high-risk, vulnerable plaques is responsible for coronary thrombosis, the main cause of unstable angina, acute myocardial infarction, and sudden cardiac death. In addition to rupture, plaque erosion may also lead to occlusive thrombosis and acute coronary events. Atherothrombosis can be evaluated according to histologic criteria, most commonly categorized by the American Heart Association (AHA) classification. However, this classification does not include the thin cap fibroatheroma, the most common form of high-risk, vulnerable plaque. Furthermore, the AHA classification does not include plaque erosion. As a result, new classifications have emerged and are reviewed in this article. The disease is asymptomatic during a long period and dramatically changes its course when complicated by thrombosis. This is summarized in five phases, from early lesions to plaque rupture, followed by plaque healing and fibrocalcification. For the early phases, the role of endothelial dysfunction, cholesterol transport, high-density lipoprotein, and proteoglycans are discussed. Furthermore, the innate and adaptive immune response to autoantigens, the Toll-like receptors, and the mechanisms of calcification are carefully analyzed. For the advanced phases, the role of eccentric remodeling, vasa vasorum neovascularization, and mechanisms of plaque rupture are systematically evaluated. In the final thrombosis section, focal and circulating tissue factor associated with apoptotic macrophages and circulatory monocytes is examined, closing the link between inflammation, plaque rupture, and blood thrombogenicity.

Recent progress in histochemistry and cell biology: the state of the art 2005

Advances in the field of histochemistry, a multidisciplinary area including the detection, localization and functional characterization of molecules in single cells and complex tissues, often drives the attainment of new knowledge in the broadly defined discipline of cell biology. These two disciplines, histochemistry and cell biology, have been joined in this journal to facilitate the flow of information with celerity from technical advancement in histochemical procedures, to their utilization in experimental models. This review summarizes advancements in these fields during the past year.

Effect of diabetes on aortic nitric oxide synthesis in spontaneously hypertensive rats; does captopril modulate this effect?

Nitric oxide (NO) is a potent regulator in the cardiovascular system; it is generated by the nitric oxide synthase (NOS) family of proteins. NO produced in endothelial cells plays a crucial role in vascular functions. The aim of this study was to clarify the effect of diabetes on aortic NO synthesis in a model of genetic hypertension and determine whether captopril modulates this effect. Diabetes was induced in ten weeks old spontaneously hypertensive rats (SHR) by streptozotocin injection. The rats were allocated into 3 groups: control group 1, non-diabetic SHR; group 2, diabetic SHR; group 3, diabetic SHR group receiving captopril at 80 mg/kg in drinking water for 4 weeks. Mean blood pressure (MBP) was measured once a week by tail-cuff method. Aortic NO metabolities (nitrite/nitrate) and endothelial NOS (NOS-3) were assayed by Griess reaction and by immunoblotting and immunohistochemistry, respectively. There was a significant decrease in nitrite/nitrate (NOx) in aortas of diabetic SHR compared with controls. The decrease of aortic NOx in diabetic SHR was accompanied by a decrease in NOS-3 expression. Captopril treatment reduced MBP without affecting either NOx level or NOS-3 expression in aortas of diabetic SHR. We conclude that STZ-induced diabetes decreased NO in aortas of SHR that may reflect endothelial cell dysfunction; captopril administration decreased MBP without affecting NO level in aortas of diabetic SHR which suggest that the blood pressure-lowering effects of captopril were independent of NO.

News and views in Histochemistry and Cell Biology

Advances in histochemical methodology and ingenious applications of novel and improved methods continue to confirm the standing of morphological means and approaches in research efforts, and contribute significantly to increasing our knowledge about structures and functions in all areas of the life sciences from cell biology to pathology. Reports published during recent months documenting this progress are summarized in the present review.