Comparison of the superb microvascular imaging technique and the color Doppler techniques for evaluating children's testicular blood flow

OBJECTIVE

We have compared conventional Color Doppler (CD) and Power Doppler (PD) techniques, which are used for evaluating the testicular blood flow in small children, and the Superb Microvascular Imaging (SMI), which is a new technique. We have also investigated their contributions to testicular evaluations.

PATIENTS AND METHODS

We evaluated blood flow in testicles using a grading system with CD, PD and SMI techniques. We determined the average duration of the three techniques.

RESULTS

There was a statistically significant difference between the SMI and CD techniques for all patients (p < 0.001, p = 0.001). When we compared the PD and SMI, either as much or more vascular information was obtained (p = 0.106). There was a statistically significant difference between the application durations of the tests (p < 0.05).

CONCLUSIONS

Superb Microvascular Imaging yields more detailed vascular information in blood flow in testicles in small children, than either CD or PD. Furthermore, this technique decreases the duration of the examination at a significant level. Superb Microvascular Imaging may represent an alternative method that can be used safely for evaluating blood flow in the testicles of small children. Additional studies may increase the reliability of SMI.

Hyperglycaemia promotes cerebral barrier dysfunction through activation of protein kinase C-β

AIM

To examine whether protein kinase C (PKC) and associated downstream mechanisms are involved in hyperglycaemia (HG)-evoked blood-brain barrier (BBB) damage.

METHODS

The activities of total PKC (Peptag assay), NADPH oxidase (lucigenin assay) and matrix metalloproteinase-2 (MMP-2; gelatin zymography) were measured in human brain microvascular endothelial cells (HBMEC) exposed to normoglycaemia (5.5 mM) or HG (25 mM) using the specific assays indicated in parentheses. The integrity and function of the in vitro models of human BBB were assessed by measurements of transendothelial electrical resistance and paracellular flux of permeability markers, respectively. Occludin protein expression was studied by immunoblotting.

RESULTS

HG significantly compromised the BBB integrity and enhanced total PKC activity to which increases in PKC-β and PKC-βII isoforms contributed the most. Elevations in NADPH oxidase and MMP-2 activities and decreases in occludin levels contributed to barrier dysfunction. Selective inhibition of PKC-β isoform prevented the changes observed in occludin expression and the aforementioned enzyme activities and thus effectively preserved barrier integrity. Similarly, apocynin, a specific NADPH oxidase inhibitor, also effectively neutralized the effects of HG on barrier integrity, MMP-2 activity, occludin expression and PKC-β activity.

CONCLUSION

HG promotes cerebral-barrier dysfunction through activation of PKC-β and consequent stimulations of oxidative stress and tight junction dissolution.

Polyorchidism and adenomatous hyperplasia of the rete testis: a case report with sonographic and magnetic resonance imaging findings and review of literature

Supernumerary testis or polyorchidism is a rare congenital anomaly with about 200 reported cases in the literature. It may be associated with cryptorchidism, testicular torsion and neoplasms. Ultrasonography and magnetic resonance imaging are effective noninvasive methods of accurately detecting polyorchidism. In most cases, ultrasonography is diagnostic and magnetic resonance imaging plays confirmatory role by providing additional information if complicated with neoplasia. We report a case of 16-year-old man with right supernumerary testis associated with adenomatous hyperplasia of the rete testis, its sonographic and magnetic resonance imaging findings and management.

Partial anomalous pulmonary venous return associated with vascular anomalies of the aorta: multidetector computed tomography findings

Partial anomalous pulmonary venous return (PAPVR) is a congenital anomaly that involves drainage of one to three pulmonary veins directly into the right heart or systemic venous system, creating a partial left-to-right shunt. This drainage is associated with cardiac abnormalities such as mitral stenosis and pulmonary stenosis, patent ductus arteriosus, and atrial septal defects. We report a case of PAPVR associated with vascular anomalies of the aorta by multidetector computed tomography in an adult female patient.

Oxidative stress and its role in the pathogenesis of ischaemic stroke

Stroke is one of the leading causes of mortality and morbidity, with astronomical financial repercussions on health systems worldwide. Ischaemic stroke accounts for approximately 80-85% of all cases and is characterised by the disruption of cerebral blood flow and lack of oxygen to the affected area. Oxidative stress culminates due to an imbalance between pro-oxidants and antioxidants and consequent excessive production of reactive oxygen species. Reactive oxygen species are biphasic, playing a role in normal physiological processes and are also implicated in a number of disease processes, whereby they mediate damage to cell structures, including lipids, membranes, proteins, and DNA. The cerebral vasculature is a major target of oxidative stress playing a critical role in the pathogenesis of ischaemic brain injury following a cerebrovascular attack. Superoxide, the primary reactive oxygen species, and its derivatives have been shown to cause vasodilatation via the opening of potassium channels and altered vascular reactivity, breakdown of the blood-brain barrier and focal destructive lesions in animal models of ischaemic stroke. However, reactive oxygen species are involved in normal physiological processes including cell signalling, induction of mitogenesis, and immune defence. Primarily, this review will focus on the cellular and vascular aspects of reactive oxygen and nitrogen species generation and their role in the pathogenesis of ischaemia-reperfusion phenomena. Secondly, the proposed mechanisms of oxidative stress-related neuronal death will be reflected upon and in summation specific targeted neuroprotective therapies targetting oxidative stress and their role in the pathogenesis of stroke will be discussed.

Antioxidants attenuate hyperglycaemia-mediated brain endothelial cell dysfunction and blood-brain barrier hyperpermeability

AIMS

Hyperglycaemia (HG), in stroke patients, is associated with worse neurological outcome by compromising endothelial cell function and the blood-brain barrier (BBB) integrity. We have studied the contribution of HG-mediated generation of oxidative stress to these pathologies and examined whether antioxidants as well as normalization of glucose levels following hyperglycaemic insult reverse these phenomena.

METHODS

Human brain microvascular endothelial cell (HBMEC) and human astrocyte co-cultures were used to simulate the human BBB. The integrity of the BBB was measured by transendothelial electrical resistance using STX electrodes and an EVOM resistance meter, while enzyme activities were measured by specific spectrophotometric assays.

RESULTS

After 5 days of hyperglycaemic insult, there was a significant increase in BBB permeability that was reversed by glucose normalization. Co-treatment of cells with HG and a number of antioxidants including vitamin C, free radical scavengers and antioxidant enzymes including catalase and superoxide dismutase mimetics attenuated the detrimental effects of HG. Inhibition of p38 mitogen-activated protein kinase (p38MAPK) and protein kinase C but not phosphoinositide 3 kinase (PI3 kinase) also reversed HG-induced BBB hyperpermeability. In HBMEC, HG enhanced pro-oxidant (NAD(P)H oxidase) enzyme activity and expression that were normalized by reverting to normoglycaemia.

CONCLUSIONS

HG impairs brain microvascular endothelial function through involvements of oxidative stress and several signal transduction pathways.

Smoking impairs endothelial function in human saphenous vein in an ex vivo model

The aim of this ex vivo experimental study was to assess the effect of smoking, diabetes mellitus, and hypertension on endothelial function in human saphenous vein, a commonly used conduit for coronary and peripheral arterial bypass surgery. A segment of long saphenous vein harvested during infrainguinal bypass surgery was mounted in an organ bath for isometric tension studies. Vein rings were precontracted to submaximal contraction with phenylephrine, followed by endothelium-dependent relaxation with acetylcholine. Long saphenous vein segments were collected from 26 patients, including five females, with a mean age of 66.4 years (range 48-92). Current smokers had impaired endothelium-dependent relaxation compared to ex- and nonsmokers (10.2%, n=13, vs. 32.9%, n=13; p<0.010). However, ex-smokers and nonsmokers did not have a significant difference in relaxant responses to acetylcholine (29.1%, n=8, vs. 24.6%, n=5; p=nonsignificant [ns]). Similarly, diabetic and nondiabetic patients did not show a significant difference in endothelium-dependent relaxation (23.1%, n=10, vs. 15.6%, n=16; p=ns). The relaxant responses in hypertensive and normotensive patients were not different (20.4%, n=12, vs. 22.5%, n=14; p=ns). Smoking has a deleterious effect on the endothelial function of saphenous vein, and smoking cessation may improve the long-term durability of saphenous vein used as a bypass graft in patients undergoing arterial reconstruction.

Carotid intima-media thickness: is it correlated with stroke side?

OBJECTIVE

The objective of the present study was to investigate the possible correlation between the common carotid artery (CCA) intima-media thickness (IMT) and the infarct side.

METHOD

The CCA IMTs in patients with atherosclerotic non-lacunar stroke were measured.

RESULTS

The mean age of the patients was 64.3 +/- 10.7 years (range 40-83 years) and 42 of 100 patients were male. The infarcts were at the left side in 53 patients and at the right side in 47 patients. The mean CCA IMT was 1.02 +/- 0.18 mm at the infarct side and 0.87 +/- 0.17 mm at the contralateral side. The difference between them was statistically significant (P < 0.01). Although the mean age of the patients with a left-sided infarct was greater than that of the patients with a right-sided infarct, the difference was not statistically significant.

CONCLUSION

Our results suggest that CCA IMT may be used in prediction of possible infarct side, and in the prediction of potential risk of stroke by evaluating the IMT of both CCAs separately.

High glucose mediates pro-oxidant and antioxidant enzyme activities in coronary endothelial cells

AIM

Excess levels of free radicals such as nitric oxide (NO) and superoxide anion (O(2)(-)) are associated with the pathogenesis of endothelial cell dysfunction in diabetes mellitus. This study was designed to investigate the underlying causes of oxidative stress in coronary microvascular endothelial cells (CMECs) exposed to hyperglycaemia.

METHODS

CMECs were cultured under normal (5.5 mmol/l) or high glucose (22 mmol/l) concentrations for 7 days. The activity and expression (protein level) of endothelial NO synthase (eNOS), inducible NOS (iNOS), NAD(p)H oxidase and antioxidant enzymes, namely, superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) were investigated by specific activity assays and Western analyses, respectively, while the effects of hyperglycaemia on nitrite and O(2)(-) generation were investigated by Griess reaction and cytochrome C reduction assay, respectively.

RESULTS

Hyperglycaemia did not alter eNOS or iNOS protein expressions and overall nitrite generation, an index of NO production. However, it significantly reduced the levels of intracellular antioxidant glutathione by 50% (p < 0.05) and increased the protein expressions and activities of p22-phox, a membrane-bound component of pro-oxidant NAD(p)H oxidase and antioxidant enzymes (p < 0.05). Free radical scavengers, namely, Tiron and mercaptopropionylglycine (MPG) (0.1-1 micromol/l) reduced hyperglycaemia-induced antioxidant enzyme activity and increased glutathione and nitrite generation to the levels observed in CMEC cultured in normoglycaemic medium (p < 0.01). The differences in enzyme activity and expressions were independent of the increased osmolarity generated by high glucose levels as investigated by using equimolar concentrations of mannitol in parallel experiments.

CONCLUSIONS

These results suggest that hyperglycaemia-induced oxidative stress may arise in CMEC as a result of enhanced pro-oxidant enzyme activity and diminished generation of antioxidant glutathione. By increasing the antioxidant enzyme capacity, CMEC may protect themselves against free radical-induced cell damage in diabetic conditions.

Antioxidant vitamins C and E ameliorate hyperglycaemia-induced oxidative stress in coronary endothelial cells

OBJECTIVE

Vitamins C and E have protective features in many disease states associated with enhanced oxidative stress. The aim of this study was to investigate whether vitamin(s) C and/or E modulate hyperglycaemia-induced oxidative stress by regulating enzymatic activities of prooxidant, i.e. NAD(P)H oxidase and/or antioxidant enzymes, namely endothelial nitric oxide synthase (eNOS), superoxide dismutase, catalase and glutathione peroxidase, using coronary microvascular endothelial cells (CMEC).

METHODS

CMEC were cultured under normal (5.5 mM) or high glucose (22 mM) concentrations for 7 days. The enzyme activities were determined by specific assays. The levels of O(2) (-) and nitrite were measured by cytochrome c reduction and Griess assays respectively.

RESULTS

Hyperglycaemia did not alter eNOS activity or overall nitrite generation, an index of NO production. However, it increased NAD(P)H oxidase and antioxidant enzyme activities (p < 0.05). Specific inhibitors of NAD(P)H oxidase, i.e. phenylarsine oxide (0.1-3 microm) and 4-(2-aminoethyl)benzenesulfonyl fluoride (5-100 microm) and vitamins C and E (0.1-1 microm) significantly reduced prooxidant and antioxidant enzyme activities in CMEC exposed to hyperglycaemia (p < 0.01). The differences in enzyme activities were independent of increases in osmolarity generated by high glucose levels as investigated by using equimolar concentrations of mannitol in parallel experiments.

CONCLUSIONS

Vitamins C and E may protect CMEC against hyperglycaemia-induced oxidative stress by concomitantly regulating prooxidant and antioxidant enzyme activities.

Investigation of the C242T polymorphism of NAD(P)H oxidase p22 phox gene and ischaemic heart disease using family-based association methods

Ischaemic heart disease is a complex phenotype arising from the interaction of genetic and environmental factors. Excessive production of reactive oxygen species leading to endothelial dysfunction is believed to be important in the pathogenesis of ischaemic heart disease. The NAD(P)H oxidase system generates superoxide anions in vascular cells; however, the role of the C242T polymorphism of the NAD(P)H oxidase p22 phox gene in ischaemic heart disease is unclear due to contradictory results from case-control studies. Consequently, we applied family-based association tests to investigate the role of this polymorphism in ischaemic heart disease in a well-defined Irish population. A total of 1023 individuals from 388 families (discordant sibships and parent/child trios) were recruited. Linkage disequilibrium between the polymorphism and ischaemic heart disease was tested using the combined transmission disequilibrium test (TDT)/sib-TDT (cTDT) and pedigree disequilibrium test (PDT). Both cTDT and PDT analyses found no statistically significant excess transmission of either allele to affected individuals (P =0.30 and P =0.28, respectively). Using robust family-based association tests specifically designed for the study of complex diseases, we found no evidence that the C242T polymorphism of the p22 phox gene has a significant role in the development of ischaemic heart disease in our population.

Aprotinin impairs endothelium-dependent relaxation in rat aorta and inhibits nitric oxide release from rat coronary endothelial cells

OBJECTIVE

Aprotinin, a non-specific serine protease inhibitor, reduces postoperative bleeding after coronary artery surgery. The mechanism of action for this 'blood-sparing' effect of aprotinin is only partially clarified. We therefore aimed to investigate the effect of aprotinin on the release of nitric oxide (NO), a vasodilator and antiaggregant factor, from rat coronary microvascular endothelial cells and on the NO-mediated endothelium-dependent relaxation of rat thoracic aorta.

METHODS

Endothelium-intact and endothelium-denuded thoracic aortic rings from Wistar rats (250-300 g) were suspended in organ chambers. Contractile and relaxant responses in the absence and presence of aprotinin (125, 250 and 500 KIU/ml) were recorded via a mechanotransducer. Coronary microvascular endothelial cells (CMEC) were isolated on a Langendorff system by collagenase perfusion of the hearts from the same rats. Calcium ionophore- (1 microM) induced release of NO from confluent cells was determined spectrophotometrically by measuring its stable metabolites, nitrite and nitrate, via Griess reaction.

RESULTS

Aprotinin selectively enhanced phenylephrine-induced contractions in endothelium-intact rat thoracic aortic rings, but not in the endothelium-denuded rings. The use of a nitric oxide synthesis inhibitor Nomega-nitro-L-arginine methyl ester (100 microM) on endothelium-intact rings produced a similar increase in phenylephrine-induced contractions. KCl-induced contractions remained unaltered. Aprotinin inhibited acetylcholine-, calcium ionophore- and L-arginine-induced endothelium-dependent relaxations, but not sodium nitroprusside-induced endothelium-independent relaxation. Aprotinin had no significant effect on basal nitrite-nitrate release from CMEC, while it inhibited calcium ionophore-induced total nitrite accumulation in the supernatants.

CONCLUSION

Aprotinin selectively impairs endothelium-dependent relaxation as well as basal NO availability in rat thoracic aortic rings and inhibits NO release from rat CMEC. This effect of the drug may contribute to its 'blood-sparing' action and may also account for the increase in perioperative restenosis risk observed in clinical practice during aprotinin therapy.

Molecular characterization and localization of the NAD(P)H oxidase components gp91-phox and p22-phox in endothelial cells

The production of reactive oxygen species (ROS) within endothelial cells may have several effects, including alterations in the activity of paracrine factors, gene expression, apoptosis, and cellular injury. Recent studies indicate that a phagocyte-type NAD(P)H oxidase is a major source of endothelial ROS. In contrast to the high-output phagocytic oxidase, the endothelial enzyme has much lower biochemical activity and a different substrate specificity (NADH>NADPH). In the present study, we (1) cloned and characterized the cDNA and predicted amino acid structures of the 2 major subunits of rat coronary microvascular endothelial cell NAD(P)H oxidase, gp91-phox and p22-phox; (2) undertook a detailed comparison with phagocytic NADPH oxidase sequences; and (3) studied the subcellular location of these subunits in endothelial cells. Although these studies revealed an overall high degree of homology (>90%) between the endothelial and phagocytic oxidase subunits, the endothelial gp91-phox sequence has potentially important differences in a putative NADPH-binding domain and in putative glycosylation sites. In addition, the subcellular location of the endothelial gp91-phox and p22-phox subunits is significantly different from that reported for the neutrophil oxidase, in that they are predominantly intracellular and collocated in the vicinity of the endoplasmic reticulum. This first detailed characterization of gp91-phox and p22-phox structure and location in endothelial cells provides new data that may account, in part, for the differences in function between the phagocytic and endothelial NAD(P)H oxidases.

Phenotypic changes in rat and guinea pig coronary microvascular endothelium after culture: loss of nitric oxide synthase activity

OBJECTIVES

Coronary microvascular endothelial cells (CMVEs) can modulate the contractile performance of the adjacent myocardium by the release of agents such as nitric oxide (NO). Most previous studies using CMVEs have been done in situ, in the intact organ. We set out to study possible differences in NO synthase (NOS) regulation between freshly isolated and cultured rat and guinea pig CMVEs.

METHODS

CMVEs were isolated from Wistar rats and Dunkin Hartley guinea pigs and then grown in culture for varying times. Fura-2 fluorescence was used to measure agonist-induced changes in CMVE intracellular calcium levels. Agonist-induced changes in CMVE cGMP levels were measured by commercial radioimmunoassay kit. Western blot analysis was used to measure endothelial, constitutive NOS (ecNOS) and soluble guanylate cyclase (sGC) protein levels. Reverse transcription, polymerase chain reactions and Southern blotting were used to measure ecNOS mRNA transcripts.

RESULTS

In both fresh (1 h post-isolation) and cultured (14 days with one passage) CMVEs of the rat and guinea pig, bradykinin (BK) and the calcium ionophore A23187 (both 1 microM) elicited significant (P < 0.01) increases in the fura-2 340/380 fluorescence ratio. In cultured CMVEs, basal cGMP levels were unaffected by exposure to BK or A23187. Exposure to sodium nitroprusside (SNP) or atrial natriuretic peptide (ANP) (both 1 microM) induced significant (P < 0.01) increases in cGMP in guinea pig cells, whereas in rat cells only ANP produced a significant (P < 0.01) response. By contrast, freshly isolated CMVEs of both species had higher basal cGMP levels than cultured cells, and on exposure to BK and A23187, responded with significant (P < 0.01) increases in cGMP. Moreover, exposure of both fresh rat and guinea pig CMVEs to SNP or ANP also resulted in significant (P < 0.01) increases in cGMP. Western blot analysis demonstrated that ecNOS and sGC protein were lost from the rat CMVEs following culture. Furthermore, there was also a significant loss of ecNOS mRNA from the rat cells following culture.

CONCLUSIONS

These data demonstrate that freshly isolated rat and guinea pig CMVEs possess ecNOS activity, and that this activity is downregulated following culture. At least for the rat, this effect would seem to lie at both the transcriptional and translational level. Furthermore, rat CMVEs have reduced activity of sGC following culture.

Selective dysregulation of nitric oxide synthase type 3 in cardiac myocytes but not coronary microvascular endothelial cells of spontaneously hypertensive rat

OBJECTIVE

Recent studies indicate that endothelial type nitric oxide synthase (NOS3) modulates cardiac systolic and diastolic function and the inotropic responsiveness to beta-adrenergic agonists, and may affect myocardial oxygen consumption. Although NOS3 is a constitutive protein, its levels of expression can be modified by various physiological and pathophysiological stimuli. We investigated whether the cell-specific expression of NOS3 mRNA and protein are altered in cardiac hypertrophy.

METHODS

Left ventricular cardiac myocytes and coronary microvascular endothelial cells were freshly isolated from 12 week old male spontaneously hypertensive rat (SHR) and matched normotensive Wistar rat hearts. NOS3 protein levels were assessed by Western analysis, and mRNA levels by RT-PCR and Southern blotting.

RESULTS

Left ventricular/body weight ratios were significantly increased in SHR compared to Wistar controls, indicating significant hypertrophy. The levels of NOS3 protein were markedly decreased in SHR compared to Wistar cardiac myocytes (by approximately 85%). By contrast, the expression of NOS3 mRNA normalized for GAPDH was increased approximately 3 fold in SHR cardiac myocytes relative to Wistar controls. In freshly isolated microvascular endothelial cells, however, levels of NOS3 protein and NOS3 mRNA were similar between the two groups.

CONCLUSIONS

The expression of NOS3 is selectively altered in cardiac myocytes but not coronary microvascular endothelial cells of young SHR hearts, with a marked decrease in NOS3 protein but an increase in NOS3 mRNA. This dysregulation of NOS3 could contribute to contractile dysfunction in left ventricular hypertrophy.

Expression of functional neutrophil-type NADPH oxidase in cultured rat coronary microvascular endothelial cells

OBJECTIVES

The production of reactive oxygen species (e.g., superoxide) by endothelial cells is relevant to tissue injury during ischemia-reperfusion, and may also play a role in intracellular signaling pathways. However, the molecular identities of the enzymes responsible for endothelial superoxide production are poorly defined, although xanthine oxidase, NADH/NADPH oxidoreductases and nitric oxide synthase are among proteins suggested to contribute. Recent studies suggest that an NADH/NADPH oxidase similar to that found in neutrophils is an important source of superoxide in vascular smooth muscle.

METHODS

We investigated whether a phagocyte-type NADH/NADPH oxidase complex is present in rat cultured coronary microvascular endothelial cells. The expression of NADPH oxidase components was studied by RT-PCR and Western blot analyses, while functional activity was assessed by measurement of superoxide production by lucigenin-enhanced chemiluminescence.

RESULTS

The major component of the phagocyte-type NADH/NADPH oxidase complex, a cytochrome b558 heterodimer, was shown to be present both at mRNA and protein levels, using oligonucleotide primers designed from published neutrophil and vascular smooth muscle sequences and anti-neutrophil antibodies respectively. Functional activity of the enzyme was also confirmed by NADPH-evoked superoxide production in cell homogenates, which was inhibited either by the superoxide chelator Tiron or by diphenyleneiodonium, an inhibitor of the oxidase.

CONCLUSIONS

A functional phagocyte-type NADPH oxidase is expressed in coronary microvascular endothelial cells, where it may contribute to the physiological and/or pathophysiological effects of reactive oxygen species. These data, together with reports of the presence of a similar oxidase in other non-phagocytic cell types, suggest that this enzyme complex is widely expressed in many tissues where it may subserve signaling and other functions.

Expression of the human gene encoding urokinase plasminogen activator receptor is activated by disruption of the cytoskeleton

The transition of a stationary cell to a motile cell is associated with the breakdown of the cytoskeleton and expression of enzymes responsible for the degradation of the extracellular matrix. Reverse transcription PCR was used to address the question of whether disruption of the microfilament and microtubule systems is a signal for the increased expression of the urokinase plasminogen activator receptor (uPAR), a key molecule involved in extracellular matrix degradation. Disruption of the cytoskeleton of human fibroblasts with cytochalasin B (1 x 10(-5) M or 1 x 10(-7) M), colchicine (1 x 10(-5) M or 5 x 10(-7) M), or nocodazole (1 x 10(-6) M) resulted in major increases in the levels of uPAR mRNA with smaller increases in uPAR protein levels. Both cycloheximide and alpha-amanitin inhibited the increase in uPAR mRNA levels, demonstrating the requirement for the de novo synthesis of a short-lived protein for transcriptional activation. In contrast to normal fibroblasts, treatment of the metastatic cell line HT1080 with either cytochalasin B or colchicine produced little change in the high levels of uPAR mRNA expressed in these cells. These data suggest that cytoskeletal disruption may contribute to cell migration by signaling an increase in uPAR synthesis.