Simultaneous hybrid repair of symptomatic femoral, iliac, and abdominal aortic aneurysms

BACKGROUND

Focal peripheral arterial aneurysms, though rare, have a relatively high association with coexisting synchronous or metachronous aneurysms. While most are asymptomatic at presentation, there is concern for aneurysm thrombosis, embolization, or rupture, which can lead to acute limb ischemia or even limb loss. These complications require early intervention with either open or endovascular surgery, oftentimes staged due to complexity.

METHOD

We describe a case of a 65-year-old male presenting with a symptomatic common femoral artery aneurysm with a simultaneous infrarenal abdominal aortic aneurysm, requiring a hybrid endovascular and open approach for operative repair due to the size and characteristics of his aneurysms.

DISCUSSION

As the consensus for the management of synchronous/metachronous aneurysms is to stage the procedures, it is important to report scenarios where a single hybrid operation was technically feasible and resulted in good patient outcomes.

CONCLUSION

This report supports the role of utilizing multiple hybrid operative techniques to best repair the respective aneurysm in a single operation, with favorable patient outcomes.

A novel small molecule approach for the treatment of propionic and methylmalonic acidemias

Propionic Acidemia (PA) and Methylmalonic Acidemia (MMA) are inborn errors of metabolism affecting the catabolism of valine, isoleucine, methionine, threonine and odd-chain fatty acids. These are multi-organ disorders caused by the enzymatic deficiency of propionyl-CoA carboxylase (PCC) or methylmalonyl-CoA mutase (MUT), resulting in the accumulation of propionyl-coenzyme A (P-CoA) and methylmalonyl-CoA (M-CoA in MMA only). Primary metabolites of these CoA esters include 2-methylcitric acid (MCA), propionyl-carnitine (C3), and 3-hydroxypropionic acid, which are detectable in both PA and MMA, and methylmalonic acid, which is detectable in MMA patients only (Chapman et al., 2012). We deployed liver cell-based models that utilized PA and MMA patient-derived primary hepatocytes to validate a small molecule therapy for PA and MMA patients. The small molecule, HST5040, resulted in a dose-dependent reduction in the levels of P-CoA, M-CoA (in MMA) and the disease-relevant biomarkers C3, MCA, and methylmalonic acid (in MMA). A putative working model of how HST5040 reduces the P-CoA and its derived metabolites involves the conversion of HST5040 to HST5040-CoA driving the redistribution of free and conjugated CoA pools, resulting in the differential reduction of the aberrantly high P-CoA and M-CoA. The reduction of P-CoA and M-CoA, either by slowing production (due to increased demands on the free CoA (CoASH) pool) or enhancing clearance (to replenish the CoASH pool), results in a net decrease in the CoA-derived metabolites (C3, MCA and MMA (MMA only)). A Phase 2 study in PA and MMA patients will be initiated in the United States.

Phylogenomics resolves major relationships and reveals significant diversification rate shifts in the evolution of silk moths and relatives

BACKGROUND

Silkmoths and their relatives constitute the ecologically and taxonomically diverse superfamily Bombycoidea, which includes some of the most charismatic species of Lepidoptera. Despite displaying spectacular forms and diverse ecological traits, relatively little attention has been given to understanding their evolution and drivers of their diversity. To begin to address this problem, we created a new Bombycoidea-specific Anchored Hybrid Enrichment (AHE) probe set and sampled up to 571 loci for 117 taxa across all major lineages of the Bombycoidea, with a newly developed DNA extraction protocol that allows Lepidoptera specimens to be readily sequenced from pinned natural history collections.

RESULTS

The well-supported tree was overall consistent with prior morphological and molecular studies, although some taxa were misplaced. The bombycid Arotros Schaus was formally transferred to Apatelodidae. We identified important evolutionary patterns (e.g., morphology, biogeography, and differences in speciation and extinction), and our analysis of diversification rates highlights the stark increases that exist within the Sphingidae (hawkmoths) and Saturniidae (wild silkmoths).

CONCLUSIONS

Our study establishes a backbone for future evolutionary, comparative, and taxonomic studies of Bombycoidea. We postulate that the rate shifts identified are due to the well-documented bat-moth "arms race". Our research highlights the flexibility of AHE to generate genomic data from a wide range of museum specimens, both age and preservation method, and will allow researchers to tap into the wealth of biological data residing in natural history collections around the globe.

Maternal and Fetal Platelet Responses and Adrenoceptor Binding Characteristics

Paired blood samples were obtained from mothers (venous) and babies (cord venous blood) at the time of delivery by caesarean section under epidural anaesthetic. Fetal platelets failed to aggregate in response to adrenaline in vitro although adrenaline could potentiate the threshold response to adenosine diphosphate (1 μM). Fetal platelet responses to collagen and 8 Arg vasopressin did not differ significantly from maternal responses. Maternal and fetal platelets also showed similar inhibition of aggregation after activation of adenylate cyclase (PGE1 and parathormone), in contrast to the inhibition of adenylate cyclase by adrenaline.

Alpha2 adrenoceptors were investigated using [3H] yohimbine binding receptor number and were reduced modestly but significantly on fetal compared to maternal platelets. The failure of fetal platelet aggregation in response to adrenaline appears to be related to a failure of receptor coupling and may represent a delayed maturation of fetal platelet alpha receptors or a response- to increased circulating catecholamines during birth.

Clinicopathologic characteristics associated with long-term survival in advanced epithelial ovarian cancer: an NRG Oncology/Gynecologic Oncology Group ancillary data study

OBJECTIVE

To identify clinicopathologic factors associated with 10-year overall survival in epithelial ovarian cancer (EOC) and primary peritoneal cancer (PPC), and to develop a predictive model identifying long-term survivors.

METHODS

Demographic, surgical, and clinicopathologic data were abstracted from GOG 182 records. The association between clinical variables and long-term survival (LTS) (>10years) was assessed using multivariable regression analysis. Bootstrap methods were used to develop predictive models from known prognostic clinical factors and predictive accuracy was quantified using optimism-adjusted area under the receiver operating characteristic curve (AUC).

RESULTS

The analysis dataset included 3010 evaluable patients, of whom 195 survived greater than ten years. These patients were more likely to have better performance status, endometrioid histology, stage III (rather than stage IV) disease, absence of ascites, less extensive preoperative disease distribution, microscopic disease residual following cyoreduction (R0), and decreased complexity of surgery (p<0.01). Multivariable regression analysis revealed that lower CA-125 levels, absence of ascites, stage, and R0 were significant independent predictors of LTS. A predictive model created using these variables had an AUC=0.729, which outperformed any of the individual predictors.

CONCLUSIONS

The absence of ascites, a low CA-125, stage, and R0 at the time of cytoreduction are factors associated with LTS when controlling for other confounders. An extensively annotated clinicopathologic prediction model for LTS fell short of clinical utility suggesting that prognostic molecular profiles are needed to better predict which patients are likely to be long-term survivors.

Abstract 489: The Role of Hemodynamics in Modulating p120 and Kaiso Expression and Activity in Atherogenesis

Introduction. The generation of atherosclerosis has been shown to be a non-random process, with endothelial cells (ECs) in regions of disturbed hemodynamics developing an atheroprone (pro-inflammatory) phenotype. While a great deal of research has focused on hemodynamic regulation of EC phenotype, the mechanisms that mediate ECs’ response to local shear stress environment remain elusive. p120-catenin (p120) and its transcription factor binding partner Kaiso are expressed in ECs and possess a variety of functions that potentially contribute to the hemodynamic regulation of EC phenotype in atherosclerosis. Specifically, p120 has been shown to regulate adherens junction stability and regulate gene transcription through interaction with Kaiso.

Hypothesis. We hypothesize hemodynamic forces modulate the activity of p120 and Kaiso in a manner that alters local endothelial susceptibility to atherogenesis.

Methods. Atheroprone/protective hemodynamic profiles obtained by human carotid artery imaging were applied to human ECs in vitro . Protein/gene expression was then analyzed by Western blot, RT-PCR, and imaging. To determine Kaiso-dependent regulation of target gene expression, siRNAs were used to knockdown Kaiso expression. For in vivo validation, vasculature from Apolipoprotein E -/- mice was isolated, fixed, and stained.

Results. In vitro, atheroprotective flow upregulates p120 expression and increases its junctional continuity and nuclear accumulation. There is a flow-dependent increase in Kaiso expression over time in both flow conditions, but p120/Kaiso interaction is increased under atheroprone flow. Kaiso knockdown under protective flow results in decreased expression of the anti-inflammatory genes eNOS (0.49 fold) and KLF2 (0.68 fold) and increased expression of the inflammatory marker VCAM (1.44 fold), suggesting a previously unknown anti-atherogenic function of Kaiso. In preliminary mouse studies, Kaiso is expressed in ECs overlying both healthy and diseased regions, as well as being highly expressed within the lesions.

Conclusions. p120 and Kaiso expression are regulated in a flow-dependent manner and are potentially a mechanism by which hemodynamics modulate susceptibility to atherogenesis.

A transgenic mouse for imaging caspase-dependent apoptosis within the skin

Apoptosis is an essential process for the maintenance of normal physiology. The ability to noninvasively image apoptosis in living animals would provide unique insights into its role in normal and disease processes. Herein, a recombinant reporter consisting of beta-galactosidase gene flanked by two estrogen receptor regulatory domains and intervening Asp-Glu-Val-Glu sequences was constructed to serve as a tool for in vivo assessment of apoptotic activity. The results demonstrate that when expressed in its intact form, the hybrid reporter had undetectable beta-galactosidase activity. Caspase 3 activation in response to an apoptotic stimulus resulted in cleavage of the reporter, and thereby reconstitution of beta-galactosidase activity. Enzymatic activation of the reporter during an apoptotic event enabled noninvasive measurement of beta-galactosidase activity in living cells, which correlated with traditional measures of apoptosis in a dose- and time-dependent manner. Using a near-infrared fluorescent substrate of beta-galactosidase (9H-{1,3-dichloro-9,9-dimethylacridin-2-one-7-yl} beta-D-galactopyranoside), noninvasive in vivo imaging of apoptosis was achieved in a xenograft tumor model in response to proapoptotic therapy. Finally, a transgenic mouse model was developed expressing the ER-LACZ-ER reporter within the skin. This reporter and transgenic mouse could serve as a unique tool for the study of apoptosis in living cells and animals, especially in the context of skin biology.

Radiosynthesis and evaluation of 5-[125I]iodoindol-3-yl-beta-D-galactopyranoside as a beta-galactosidase imaging radioligand

The synthesis and investigation of 5-[125I]iodoindol-3-yl-beta-d-galactopyranoside ([125I]IBDG) as a radioligand for single-photon emission computed tomography (SPECT) imaging of b-galactosidase expression are described. No-carrier-added [125I]IBDG was synthesized by a radioiododestannylation approach in > 75% overall radiochemical yield and > 99% radiochemical purity. [125I]IBDG was evaluated as a substrate using beta-galactosidase-expressing (D54L) and nonexpressing (D54) human glioma cell lines. A 24-hour incubation of this substrate with cultured cells revealed a 6.5-fold greater intracellular trapping of radioactivity in D54L cells compared with D54 cells. Systemic delivery of [125I]IBDG in nude mice bearing D54L tumors failed to show significant trapping of radioactivity within these tumors by SPECT imaging. In contrast, intratumoral injection of the substrate resulted in efficient trapping of radioactivity in D54L tumors but not D54 tumors, resulting in clear SPECT visualization of the former tumor. Based on dynamic SPECT imaging and blood metabolite analysis, we conclude that although [125I]IBDG is an efficient in vivo substrate for beta-galactosidase, its rapid renal clearance hampers its intratumoral availability on systemic administration.

Evaluation of D-methionine as a novel oral radiation protector for prevention of mucositis

PURPOSE

Oral mucositis is a common acute morbidity associated with radiation and/or chemotherapy treatment for cancer. D-Methionine (D-Met), the dextro-isomer of the common amino acid l-methionine, has been documented to protect normal tissues from a diverse array of oxidative insults.

EXPERIMENTAL DESIGN

We evaluated if D-Met could selectively prevent radiation-induced oral mucositis using in vitro cell culture models as well as an in vivo model of radiation injury to the oral mucosa in C3H mice.

RESULTS

Unlike free-radical scavengers, which protected both normal and transformed tumor cells in vitro from radiation-induced cell death, treatment with d-Met in culture protected nontransformed primary human cells from radiation-induced cell death (protective factor between 1.2 and 1.6; P<0.05) whereas it did not confer a similar protection on transformed tumor cells. D-Met treatment also provided significant protection to normal human fibroblasts, but not to tumor cell lines, from radiation-induced loss of clonogenicity (protection factor, 1.6+/-0.15). D-Met treatment did not alter DNA damage (as measured by histone phosphorylation) following irradiation but seemed to selectively mitigate the loss of mitochondrial membrane potential in nontransformed cells, whereas it did not provide a similar protection to tumor cells. Tumor control of implanted xenografts treated with radiation or concurrent cisplatin and radiation was not altered by D-Met treatment. Pharmacokinetics following administration of a liquid suspension of D-Met in rats showed 68% bioavailability relative to i.v. administration. Finally, in a murine model of mucositis, a dose-dependent increase in protection was observed with the protective factor increasing from 1.6 to 2.6 over a range of oral D-Met doses between 200 and 500 mg/kg (P<0.0003).

CONCLUSIONS

D-Met protected normal tissues, but not tumor cells, in culture from radiation-induced cell death; it also protected normal cells from radiation-induced mucosal injury in a murine model but did not alter tumor response to therapy. Further studies on the use of D-Met to protect from oral mucositis are warranted.

Identification of inhibitors using a cell-based assay for monitoring Golgi-resident protease activity

Noninvasive real-time quantification of cellular protease activity allows monitoring of enzymatic activity and identification of activity modulators within the protease's natural milieu. We developed a protease activity assay based on differential localization of a recombinant reporter consisting of a Golgi retention signal and a protease cleavage sequence fused to alkaline phosphatase (AP). When expressed in mammalian cells, this protein localizes to Golgi bodies and, on protease-mediated cleavage, AP translocates to the extracellular medium where its activity is measured. We used this system to monitor the Golgi-associated protease furin, a pluripotent enzyme with a key role in tumorigenesis, viral propagation of avian influenza, ebola, and HIV as well as in activation of anthrax, pseudomonas, and diphtheria toxins. This technology was adapted for high-throughput screening of 39,000-compound small molecule libraries, leading to identification of furin inhibitors. Furthermore, this strategy was used to identify inhibitors of another Golgi protease, the beta-site amyloid precursor protein (APP)-cleaving enzyme (BACE). BACE cleavage of the APP leads to formation of the Abeta peptide, a key event that leads to Alzheimer's disease. In conclusion, we describe a customizable noninvasive technology for real-time assessment of Golgi protease activity used to identify inhibitors of furin and BACE.

Uterine papillary serous and clear cell carcinomas predict for poorer survival compared to grade 3 endometrioid corpus cancers

To compare the survival of women with uterine papillary serous carcinoma (UPSC) and clear cell carcinoma (CC) to those with grade 3 endometrioid uterine carcinoma (G3EC). Demographic, pathologic, treatment, and survival information were obtained from the Surveillance, Epidemiology, and End Results Program from 1988 to 2001. Data were analysed using Kaplan–Meier and Cox proportional hazards regression methods. Of 4180 women, 1473 had UPSC, 391 had CC, and 2316 had G3EC cancers. Uterine papillary serous carcinoma and CC patients were older (median age: 70 years and 68 vs 66 years, respectively; P<0.0001) and more likely to be black compared to G3EC (15 and 12% vs 7%; P<0.0001). A higher proportion of UPSC and CC patients had stage III–IV disease compared to G3EC patients (52 and 36% vs 29%; P<0.0001). Uterine papillary serous carcinoma, CC and G3EC patients represent 10, 3, and 15% of endometrial cancers but account for 39, 8, and 27% of cancer deaths, respectively. The 5-year disease-specific survivals for women with UPSC, CC and G3EC were 55, 68, and 77%, respectively (P<0.0001). The survival differences between UPSC, CC and G3EC persist after controlling for stage I–II (74, 82, and 86%; P<0.0001) and stage III–IV disease (33, 40, and 54; P<0.0001). On multivariate analysis, more favourable histology (G3EC), younger age, and earlier stage were independent predictors of improved survival. Women with UPSC and CC of the uterus have a significantly poorer prognosis compared to those with G3EC. These findings should be considered in the counselling, treating and designing of future trials for these high-risk patients.

Is imaging at intermediate doses necessary during dobutamine stress magnetic resonance imaging?

To determine if visualization of left ventricular contraction throughout the course of a pharmacologic stress test performed with magnetic resonance imaging (MRI) (rather than solely at baseline and peak stress) is necessary, we retrospectively reviewed dobutamine MRI results in 469 consecutively referred patients for diagnosis of inducible ischemia. At each stage of pharmacologic stress, six image planes of the heart were viewed and left ventricular wall motion was scored as normal, hypokinetic, akinetic, or dyskinetic. Inducible ischemia was identified in 102 patients; in 39 patients (38%), evidence of ischemia occurred before receiving high doses of dobutamine. During testing, 103 patients developed chest discomfort consistent with angina, but only 26 of the 103 patients (25%) developed new wall motion abnormalities indicative of ischemia. Continuous image acquisition and review during dobutamine MRI pharmacologic stress testing provides a mechanism to detect ischemia and avoid premature test termination during the early stages of the procedure. Compared with protocols that image only at baseline and at peak stress, continuous acquisition and review may enhance the safety and improve the diagnostic accuracy of pharmacologic stress testing during dobutamine MRI.

Vasorelaxant properties of isolated human radial arteries: comparison with internal mammary arteries

Radial arteries, used in revascularisation surgery, are prone to spasm. We have examined the ability of nitrovasodilators, calcium channel blockers, and K(ATP) channel openers to cause vasodilation, and to attenuate contractions due to depolarisation and receptor activation in radial and mammary arteries used in coronary artery bypass graft surgery. Two to three millimetre rings of artery obtained from patients at surgery were studied in organ baths in vitro. Constriction to KC1 and phenylephrine was examined before and again after treatment of the rings with drug or vehicle. Calcium channel blockers were the only compounds to inhibit contractions to both KC1 and phenylephrine. Sodium nitroprusside attenuated constriction to phenylephrine but not KC1 in both vessels. K(ATP) channel openers similarly attenuated constriction to phenylephrine in radial arteries but were much less effective in mammary arteries. These studies support the continued use of calcium blockers after revascularisation with radial artery but suggest that other classes of drug may be as effective at minimising spasm due to receptor mediated constriction.

Adenovirus-mediated overexpression of extracellular superoxide dismutase improves endothelial dysfunction in a rat model of hypertension

Gene transfer may be appropriate for therapeutic protocols targeted at the vascular endothelium. Endothelial dysfunction is the principal phenotype associated with atherosclerosis and hypertension. Oxidative stress has been implicated in the development of endothelial dysfunction. We have explored the ability of overexpressing anti-oxidant genes (superoxide dismutases; SODs) in vitro and in vivo to assess their potential for reversing endothelial dysfunction in a rat model, the stroke-prone spontaneously hypertensive rat (SHRSP). Western blotting and immunofluorescence assays in vitro showed efficient overexpression of MnSOD and ECSOD with respect to localisation to the mitochondria and extracellular surface, respectively. Transgene functional activity was quantified with SOD activity assays. MnSOD and ECSOD overexpression in intact SHRSP vessels in vivo led to endothelial and adventitial overexpression. Pharmacological assessment of transduced vessels following in vivo delivery by basal NO availability quantification demonstrated that the "null" adenovirus and MnSOD adenovirus did not significantly increase NO availability. However, AdECSOD-treated carotid arteries showed a significant increase in NO availability (1.91 +/- 0.04 versus 0.75 +/- 0.08 g/g, n = 6, P = 0.029). In summary, efficient overexpression of ECSOD, but not MnSOD in vivo, results in improved endothelial function in a rat model of hypertension and has important implications for the development of endothelial-based vascular gene therapy.

Vacuolar H+-ATPase, but not mitochondrial F1F0-ATPase, is required for aluminum resistance in Saccharomyces cerevisiae

It was recently shown that vacuolar ATPase and mitochondrial F1F0-ATPase activities are induced by aluminum (Al) in an Al-resistant cultivar of wheat, suggesting that induction of these enzymes could be an adaptive trait involved in Al resistance. To test this hypothesis, we used the Saccharomyces cerevisiae model system. In yeast, unlike wheat, the activity, transcript and protein levels of mitochondrial F1F0-ATPase, but not vacuolar ATPase, are induced by Al, while plasma membrane P-ATPase activity is inhibited. However, yeast vacuolar ATPase mutant strains are hypersensitive to Al, while F1F0-ATPase mutant strains exhibit wild-type growth. These data suggest that vacuolar ATPase activity is involved in Al resistance, with ATP required for this activity supplied by mitochondrial F1F0-ATPase or fermentation.

Detecting left ventricular myocardial ischemia during intravenous dobutamine with cardiovascular magnetic resonance imaging (MRI)

Advances in computer software, scanner hardware, and hemodynamic monitoring equipment have permitted the development of cardiovascular stress testing protocols for use during intravenous Dobutamine infusions within magnetic resonance imaging (MRI) scanners. Recent studies have documented that the safety profile and clinical utility of Dobutamine/Atropine cardiac stress testing during MRI compares favorably with other noninvasive stress imaging modalities and is particularly useful in patients not well suited for stress echocardiograms.

Cardiac cycle-dependent changes in aortic area and distensibility are reduced in older patients with isolated diastolic heart failure and correlate with exercise intolerance

OBJECTIVES

The goal of this study was to determine if cardiac cycle-dependent changes in proximal thoracic aortic area and distensibility are associated with exercise intolerance in elderly patients with diastolic heart failure (DHF).

BACKGROUND

Aortic compliance declines substantially with age. We hypothesized that a reduction in cardiac cycle-dependent changes in thoracic aortic area and distensibility (above that which occurs with aging) could be associated with the exercise intolerance that is prominent in elderly diastolic heart failure patients.

METHODS

Thirty subjects (20 healthy individuals [10 < 30 years of age and 10 > 60 years of age] and 10 individuals > the age of 60 years with DHF) underwent a magnetic resonance imaging (MRI) study of the heart and proximal thoracic aorta followed within 48 h by maximal exercise ergometry with expired gas analysis.

RESULTS

The patients with DHF had higher resting brachial pulse and systolic blood pressure, left ventricular mass, aortic wall thickness and mean aortic flow velocity, and, compared with healthy older subjects, they had a significant reduction in MRI-assessed cardiac cycle-dependent change in aortic area and distensibility (p < 0.0001) that correlated with diminished peak exercise oxygen consumption (r = 0.79). After controlling for age and gender in a multivariate analysis, thoracic aortic distensibility was a significant predictor of peak exercise oxygen consumption (p < 0.04).

CONCLUSIONS

Older patients with isolated DHF have reduced cardiac cycle-dependent changes in proximal thoracic aortic area and distensibility (beyond that which occurs with normal aging), and this correlates with and may contribute to their severe exercise intolerance.

Is hydrogen peroxide an EDHF in human radial arteries?

In human radial arteries, a nitric oxide/prostanoid-independent mechanism that has the pharmacological characteristics of an EDHF contributes to endothelium-dependent relaxation. H2O2 can act as an EDHF in some vascular beds. We examined the hypothesis that endogenously produced H2O2 mediated the nitric oxide/prostanoid-independent relaxation to carbachol in radial arteries obtained from patients undergoing coronary artery bypass surgery. Superoxide levels, measured by chemiluminescence, were similar in radial and internal mammary arteries, but immunohistochemical staining for Cu/Zn superoxide dismutase (SOD) was lower in endothelium from radial arteries. In organ chamber studies, neither addition of catalase nor addition of SOD to the bathing fluid modified nitric oxide/prostanoid-independent relaxations to carbachol in radial arteries. However, nitric oxide-dependent vasorelaxation was enhanced in the presence of SOD. Thus the nitric oxide/prostanoid-independent relaxation to carbachol is not due to H2O2 and, unlike nitric oxide-mediated vasorelaxation, is not attenuated by superoxide. Blood vessels showing EDHF-mediated relaxations resistant to oxidative stress may provide favorable outcomes in revascularization surgery.

Radial artery hypertrophy occurs in coronary atherosclerosis and is independent of blood pressure

Endothelial dysfunction, believed to underlie the structural changes of atherosclerosis, is a systemic phenomenon. Despite this, the radial artery has been considered as devoid of atherosclerosis and is commonly used as a conduit in coronary artery bypass grafting (CABG). Recently, histological study has shown intimal hyperplasia and other structural changes consistent with early atherosclerosis in the radial artery. The objective of the present study was to determine if structural changes in the radial artery could be detected in vivo in patients with coronary atherosclerosis. Using high resolution echo-tracking, measurements of radial artery internal diameter, wall thickness and wall cross-sectional area were made in 25 patients awaiting CABG and in 20 controls. Digital and brachial blood pressures were also recorded. Mean arterial pressures did not differ between the patient and control groups. All measures of wall thickness were greater in the patient than the control group. Neither current arterial pressures nor past history of hypertension correlated with wall thickness. Using a model of analysis of covariance, coronary artery disease was the best single predictor of intima-media thickness, R(2)=48%, n=44, P<0.0005. We concluded that increased radial artery wall thickness can be demonstrated in vivo in patients with coronary atherosclerosis. This is a novel observation which seems to be independent of blood pressure, and is consistent both with the hypothesis of systemic endothelial dysfunction leading to systemic structural changes and also to the recent histological evidence for atherosclerotic changes in this vessel.

Induction of vacuolar ATPase and mitochondrial ATP synthase by aluminum in an aluminum-resistant cultivar of wheat

Two 51-kD aluminum (Al)-induced proteins (RMP51, root membrane proteins of 51 kD) were recently discovered in an aluminum-resistant cultivar of wheat (Triticum aestivum) cv PT741 (Basu et al., 1994a). These proteins segregate with the aluminum resistance phenotype in a segregating population arising from a cross between Al-resistant cv PT741 and Al-sensitive cv Katepwa (Taylor et al., 1997). The proteins have been purified by continuous elution electrophoresis and analyzed by peptide microsequencing. Sequence analysis of the purified peptides revealed that they are homologous to the B subunit of the vacuolar H+-ATPase (V-ATPase) and the alpha- and beta-subunits of the mitochondrial ATP synthase (F1F0-ATPase). To confirm that these ATPases are induced by Al, ATPase activity and transcript levels were analyzed under Al stress. Both V-ATPase and F1F0-ATPase activities were induced by Al and responded in a dose-dependent manner to 0 to 150 microM Al. In contrast, plasma membrane H+-ATPase (P-ATPase) activity decreased to 0.5x control levels, even when plants were exposed to 25 microM Al. Northern analysis showed that the transcript encoding the B subunit of V-ATPase increased by 2.2x in a dose-dependent manner, whereas levels of the transcript encoding the alpha-subunit of F1F0-ATPase remained constant. The effect of Al on ATPase activity in other cultivars was also examined. The Al-resistant cultivar, cv PT741, was the only cultivar to show induction of V- and F1F0-ATPases. These results suggest that the V-ATPase in cv PT741 is responding specifically to Al stress with the ATP required for its activity supplied by ATP synthase to maintain energy balance within the cell.

Effect of excisional therapy and highly active antiretroviral therapy on cervical intraepithelial neoplasia in women infected with human immunodeficiency virus

OBJECTIVE

Our purpose was to determine the rates of recurrence, persistence, and progression of cervical intraepithelial neoplasia in women who were seropositive for human immunodeficiency virus after excisional therapy with and without highly active antiretroviral therapy.

STUDY DESIGN

The records of 118 women with cervical intraepithelial neoplasia, 56 of whom were infected with human immunodeficiency virus and 62 of whom were not infected, were examined to compare outcomes. Demographic, behavioral, and clinical indices were analyzed.

RESULTS

Of 54 women infected with human immunodeficiency virus, 31 (57.4%) had persistent or recurrent cervical intraepithelial neoplasia, in comparison with 10 (16.7%) of 60 noninfected women (P <.01). Progression occurred in 4 (16.7%) of 54 in the infected group and in 3 (5.0%) of 60 in the noninfected group (P <.05). In 21 (60.0%) of 35 infected women, in comparison with 8 (32%) of 25 noninfected women, disease persisted 6 months after diagnosis if treatment was not given (P <.05). Of 19 infected women, 10 (52.6%) had recurrent disease after treatment, compared with 2 (5.7%) of 35 noninfected women (P <.01). Risk factors for recurrence in women who were seropositive for human immunodeficiency virus included margin involvement of specimens obtained by loop electrosurgical excision (87.5% vs 20.0%l; P <.05). Exposure to highly active antiretroviral therapy, including therapy with protease inhibitors, was associated with a lower recurrence or persistence rate (17.6% vs. 70.3%; P <.05) and a lower progression rate (0% vs. 24%; P <.05).

CONCLUSION

Women infected with human immunodeficiency virus had high rates of recurrent and persistent cervical intraepithelial neoplasia despite standard therapy. Low CD4(+) levels and margin involvement of specimens obtained by loop electrosurgical excision are risk factors for recurrence. The use of highly active antiretroviral therapy is associated with a lower risk of recurrence, persistence, and progression of cervical intraepithelial neoplasia.

Oxidative stress and vascular damage in hypertension

Oxidative stress, a state of excessive reactive oxidative species activity, is associated with vascular disease states such as hypertension. In this review, we discuss the recent advances in the field of reactive oxidative species-mediated vascular damage in hypertension. These include the identification of redox-sensitive tyrosine kinases, the characterization of enzymatic sources of superoxide production in human blood vessels, and their relationship with vascular damage in atherosclerosis and hypertension. Finally, recent developments in the search for strategies to attenuate vascular oxidative stress are reviewed.

Superoxide excess in hypertension and aging: a common cause of endothelial dysfunction

There is evidence in humans that hypertension and aging similarly impair endothelial function, although the mechanism remains unclear. Superoxide anion (O(2)(-)) is a major determinant of nitric oxide (NO) bioavailability and thus endothelial function. We sought to determine the relationship between endothelial function, O(2)(-), and age in normotensive Wistar-Kyoto (WKY) and stroke-prone spontaneously hypertensive rats (SHRSP). Aortic rings were removed from female WKY and SHRSP at 3 to 4 months (young) and 9 to 12 months (old). O(2)(-) generation by aortic rings was measured before and after removal of the endothelium or incubation with N(G) nitro-L-arginine methyl ester, diphenyleneiodonium, or apocynin. Levels of p22phox were studied with immunohistochemistry and used as a marker of NAD(P)H oxidase expression. NO bioavailability was significantly lower in old WKY compared with young WKY (P=0.0009) and in old SHRSP compared with young SHRSP (P=0.005). O(2)(-) generation was significantly greater in old WKY compared with young WKY (P=0.0001). Removal of the endothelium and N(G) nitro-L-arginine methyl ester treatment resulted in a significant reduction in O(2)(-) generation in old SHRSP (P=0.009 and 0.001, respectively). Diphenyleneiodonium significantly reduced O(2)(-) generation in 12-month WKY (P=0.008) and 12-month SHRSP (P=0.009). Apocynin attenuated O(2)(-) generation by older WKY (P=0.038) and SHRSP (P=0.028). p22phox was increased in older animals compared with young. We conclude that NO bioavailability decreases with age in female WKY and SHRSP. O(2)(-) generation increases with age in WKY and is higher in SHRSP and may contribute to the reduced NO by scavenging. NAD(P)H oxidase may contribute to the age-related increase in O(2)(-).

Gene transfer of endothelial nitric oxide synthase but not Cu/Zn superoxide dismutase restores nitric oxide availability in the SHRSP

OBJECTIVE

Previous studies from our group have shown a deficit in nitric oxide (NO) bioavailability and an excess production of the superoxide anion (O(2)(-)) in the stroke prone spontaneously hypertensive rat (SHRSP) compared to the normotensive Wistar Kyoto (WKY) strain. This present study has investigated whether adenoviral-mediated gene transfer of human eNOS or Cu/ZnSOD can alter the NO/O(2)(-) balance, thereby improving endothelial function.

METHODS

A recombinant adenovirus, Ad/Hu/eNOS, containing the human eNOS cDNA fragment was generated by homologous recombination in 293 cells. Ad/Hu/eNOS or Ad/Cu/ZnSOD was delivered into SHRSP carotid arteries in vivo, using a titre of 2x10(9)-2x10(10) plaque forming units (pfu)/ml, and the effect on gene expression was observed 24 h later.

RESULTS

Western blotting confirmed increased enzyme levels of eNOS and Cu/ZnSOD in the viral-infused vessels. Ex vivo, the pressor response to phenylephrine (PE) in the presence of L-NAME was increased in the eNOS-infused arteries relative to the contralateral controls, indicating restoration of basal NO availability to that observed in untreated control WKY rats. Infusion of the SOD virus produced a statistically insignificant increase in NO bioavailability.

CONCLUSIONS

Our results support our previous findings obtained using a bovine eNOS recombinant adenovirus, that recombinant adenoviral gene transfer of human eNOS has a significant effect on NO bioavailability. In contrast, AdCu/ZnSOD gene transfer does not elicit an effect in our model. These results indicate that short-term overexpression of a recombinant eNOS, but not Cu/ZnSOD gene, in carotid arteries of the SHRSP is an effective means of locally increasing NO bioavailability to improve endothelial function.

Assessment of coronary arterial restenosis with phase-contrast magnetic resonance imaging measurements of coronary flow reserve

BACKGROUND

After successful percutaneous coronary arterial revascularization, 25% to 60% of subjects have restenosis, a recurrent coronary arterial narrowing at the site of the intervention. At present, restenosis is usually detected invasively with contrast coronary angiography. This study was performed to determine if phase-contrast MRI (PC-MRI) could be used to detect restenosis noninvasively in patients with recurrent chest pain after percutaneous revascularization.

METHODS AND RESULTS

Seventeen patients (15 men, 2 women, age 36 to 77 years) with recurrent chest pain >3 months after successful percutaneous intervention underwent PC-MRI measurements of coronary artery flow reserve followed by assessments of stenosis severity with computer-assisted quantitative coronary angiography. The intervention was performed in the left anterior descending coronary artery in 15 patients, one of its diagonal branches in 2 patients, and the right coronary artery in 1 patient. A PC-MRI coronary flow reserve value </=2.0 was 100% and 82% sensitive and 89% and 100% specific for detecting a luminal diameter narrowing of >/=70% and >/=50%, respectively.

CONCLUSIONS

Assessments of coronary flow reserve with PC-MRI can be used to identify flow-limiting stenoses (luminal diameter narrowings >70%) in patients with recurrent chest pain in the months after a successful percutaneous intervention.

Investigation into the sources of superoxide in human blood vessels: angiotensin II increases superoxide production in human internal mammary arteries

BACKGROUND

Increased vascular superoxide anion (.O(2)(-)) production contributes to endothelial dysfunction and hypertension in animal models of cardiovascular disease. Observations in experimental animals suggest that angiotensin II (Ang II) increases.O(2)(-) production by activation of vascular NAD(P)H oxidase. We studied the sources of.O(2)(-) production in human blood vessels and investigated whether, and by what mechanism, Ang II might alter vascular.O(2)(-) production.

METHODS AND RESULTS

Internal mammary arteries (IMAs) and saphenous veins (SVs) were collected at the time of cardiac surgery. Vessels were incubated in Krebs buffer at 37 degrees C.O(2)(-) was measured by lucigenin chemiluminescence. Basal. O(2)(-) concentrations were greater in IMAs than SVs. Inhibitors of NAD(P)H oxidase (10 micromol/L to 200 micromol/L diphenyleneiodonium) and xanthine oxidase (1 mmol/L allopurinol) caused reductions in.O(2)(-) concentrations in both IMAs and SVs. Western blotting of superoxide dismutase proteins demonstrated similar expression in IMAs and SVs. Vessels were also incubated in the presence or absence of Ang II (1 pmol/L to 1 micromol/L). Ang II increased.O(2)(-) production in IMAs at 4 hours of incubation (control, 978+/-117 pmol. min(-1). mg(-1); 1 micromol/L of Ang II, 1690+/-213 pmol. min(-1). mg(-1); n=27, P=0.0001, 95% CI 336, 925) but not in SVs. This effect was completely inhibited by coincubation of IMAs with DPI (100 micromol/L), a nonspecific Ang II antagonist ([sar(1), thre(8)]-Ang II, 1 micromol/L) and a specific Ang II type 1 (AT(1)) receptor antagonist (losartan, 1 micromol/L). Conclusions-. O(2)(-) production is greater in human IMAs than in SVs. NAD(P)H oxidase and xanthine oxidase are sources of.O(2)(-) production in these vessels. The vasoactive peptide Ang II increases.O(2)(-) production in human arteries by an AT(1) receptor-dependent mechanism.

Therapeutic response to assisted suicide request

The authors review the first publicly reported case of legal assisted suicide in the United States and discuss possible clinical responses other than assistance in suicide. Psychiatric observers have noted that acceptance of assisted suicide or euthanasia as a medical option has resulted in loss of knowledge about how to respond to suicidal ideation in the seriously ill. The authors discuss specific therapeutic interventions that may be appropriate for seriously ill patients requesting suicide.

A randomized, prospective study measuring outcomes after antibiotic therapy intervention by a multidisciplinary consult team

Our aim was to identify financial and outcome benefits of therapeutic intervention by a multidisciplinary antimicrobial treatment team composed of pharmacists, a clinical microbiologist, and an infectious disease specialist. Of 252 consecutive inpatients receiving suboptimal intravenous antibiotics identified by the clinical pharmacist, 127 were prospectively randomized to intervention and 125 to a control group. The groups were similar with regard to severity of illness, infection type, and time from admission to randomization. Physicians received timely, detailed reviews of relevant microbiologic and clinical data with recommendations of possible optimal antibiotic choices, dosages, and rationales. Median length of stay after randomization for control and intervention groups was 9.0 days and 5.7 days, respectively (3.3-day difference, p=0.0001). Fifteen (12.0%) and eight patients (6.3%), respectively, died, although the time-specific mortality risk was not significantly different when length of postrandomization follow-up and time to death were taken into account. Physician acceptance of suggestions was 89%. Median patient charges for radiology, laboratory, pharmacy, and room were reduced by $4404/intervention, and median hospital costs were reduced by $2642/intervention. A multidisciplinary antimicrobial therapy team can be a useful information source for physicians, improve outcomes in hospitalized patients receiving intravenous antimicrobials, and result in substantial cost savings.

Utility of fast cine magnetic resonance imaging and display for the detection of myocardial ischemia in patients not well suited for second harmonic stress echocardiography

BACKGROUND

Some patients referred for pharmacological stress testing with transthoracic echocardiography (TTE) are unable to undergo testing owing to poor acoustic windows. Fast cine MRI can be used to assess left ventricular contraction, but its utility for detection of myocardial ischemia in patients poorly suited for echocardiography is unknown.

METHODS AND RESULTS

One hundred fifty-three patients (86 men and 67 women aged 30 to 88 years) with poor acoustic windows that prevented adequate second harmonic TTE imaging were consecutively referred for MRI to diagnose inducible myocardial ischemia during intravenous dobutamine and atropine. Diagnostic studies were completed in an average of 53 minutes. No patients experienced myocardial infarction, ventricular fibrillation, exacerbation of congestive heart failure, or death. In patients who underwent computer-assisted quantitative coronary angiography, the sensitivity and specificity for detecting a >50% luminal diameter narrowing were 83% and 83%, respectively. In the 103 patients with a negative MRI examination, the cardiovascular occurrence-free survival rate was 97%.

CONCLUSIONS

Fast cine cardiac MRI provides a mechanism to assess left ventricular contraction and diagnose inducible myocardial ischemia in patients not well suited for stress echocardiography.

Decreased basal despite enhanced agonist-stimulated effects of nitric oxide in 12-week-old stroke-prone spontaneously hypertensive rat

This study examined both basal and agonist-stimulated effects of nitric oxide in rings of thoracic aorta and carotid artery from 12-week-old stroke-prone spontaneously hypertensive rats (SHRSP) and compared them to those found in rings from normotensive Wistar Kyoto (WKY) controls. Acetylcholine-induced endothelium-dependent relaxation was found to be five-fold more sensitive in both male and female SHRSP when compared with those from age- and sex-matched WKY rats. In contrast, we found a reduction in the effects of basal nitric oxide in the SHRSP rat. Specifically, the ability of basal nitric oxide to depress contractile responses to phenylephrine was found to be reduced in vessels from SHRSP when compared with those from WKY rats. In addition, the endothelium-dependent depression of vasodilator responses to the nitric oxide donor, glyceryl trinitrate, was reduced in vessels from SHRSP when compared to those from WKY rats. Thus, we have shown that the effects of basal nitric oxide are impaired in the SHRSP rat at an age when the effects of agonist-stimulated nitric oxide are actually enhanced. This impairment may be related to the greater susceptibility of basal nitric oxide to destruction by superoxide anion which is known to be produced in excess in this model of hypertension.

Gene transfer of endothelial nitric oxide synthase improves nitric oxide-dependent endothelial function in a hypertensive rat model

OBJECTIVE

We have shown previously that there is a relative nitric oxide deficiency at the level of vascular endothelium in the stroke-prone spontaneously hypertensive rat (SHRSP), a model of human essential hypertension, as compared to its normotensive reference strain Wistar Kyoto (WKY) rat. The aim of the current study was to investigate whether adenoviral-mediated gene transfer of an endothelial nitric oxide synthase (eNOS) cDNA (AdCMVeNOS) into carotid arteries of the SHRSP may improve endothelial function.

METHODS

Enzyme activity of the recombinant eNOS protein encoded by AdCMVeNOS was tested using a Griess assay in endothelial cells in culture. Left carotid arteries of SHRSP were surgically isolated and exposed to either the AdCMVeNOS or control beta-galactosidase-containing virus, (2 x 10(9) pfu/ml) ex vivo and in vivo. The vessels were harvested 24 h after surgery and analysed by Western blotting, immunohistochemistry and by examining endothelial function ex vivo.

RESULTS

Cultured endothelial cells showed almost 100% transduction with both viruses and a dose response of eNOS expression showed a five-fold increase in nitrite production for AdCMVeNOS with no change for beta-galactosidase-containing virus. Western blotting demonstrated a significant increase of eNOS expression in vessels infused with AdCMVeNOS when compared to controls. Immunohistochemistry showed highly positive staining with monoclonal antibodies against eNOS in the intact endothelial cells of the AdCMVeNOS infused vessels. The areas under the curve of the concentration responses to phenylephrine (10(-9) to 3 x 10(-6) M) in the absence and presence of NG-nitroarginine methyl ester (100 microM) showed increased basal nitric oxide bioavailability in the carotid arteries infused with AdCMVeNOS compared to the control (n = 6 for each; P = 0.0069; 95% CI, 0.864 to 3.277).

CONCLUSIONS

Our results show that AdCMVeNOS is an effective tool for vascular gene transfer and that it can improve endothelial NO availability in the SHRSP, a genetic model of essential hypertension and endothelial dysfunction.

Health education for adolescents with abnormal Pap smears

No model that meets the educational and psychosocial needs of adolescents with abnormal Pap smears has been proven effective. The Mount Sinai Adolescent Health Center (AHC) combines early identification, appropriate treatment, and follow-up of such patients. In conjunction with medical care, the AHC provides health education, risk assessment, and risk reduction. This article outlines how the AHC provides reproductive health education and counseling for adolescents with abnormal Pap smears.

Magnetization transfer imaging of skeletal muscle in autosomal recessive limb girdle muscular dystrophy

PURPOSE

The purpose of this work was to characterize magnetization transfer (MT) contrast of skeletal muscles in limb girdle muscular dystrophy (LGMD).

METHOD

The calf muscles of five LGMD patients and 10 normal volunteers were imaged with an off-resonance MT suppression pulse applied to T1-weighted images. MT suppression ratios were calculated for anterior tibialis, posterior tibialis, soleus, and gastrocnemius muscles in the LGMD and control groups. The relationship between MT of individual muscles and the duration of LGMD symptoms was determined.

RESULTS

Strong MT contrast was observed in normal calf muscles, with mean (+/-SD) suppression ratios ranging from 37.9% (+/-3.0) to 41.1% (+/-2.1). In diseased muscle, MT signal suppression ranged from 11 to 38%, demonstrating an inverse relationship between symptom duration and suppression ratios. MT contrast in the LGMD patients, as a reflection of muscle tissue integrity, was preserved in posterior or anterior tibialis, soleus, and gastrocnemius muscles, respectively. Suppression ratios were dramatically reduced in muscles with gross fatty infiltration but also were reduced in muscle tissues without visual evidence of fatty infiltration.

CONCLUSION

MT imaging provides a quantitative measure of pathologic changes occurring within the skeletal muscles of patients with LGMD relative to normal and may be useful in evaluating disease extent, progression, and response to new therapies as they become available.

Depiction of intracranial vessels with MRA: utility of magnetization transfer saturation and gadolinium

PURPOSE

The purpose of this work was to quantitate the individual and combined effects of magnetization transfer (MT) saturation and gadolinium (Gd) on the visualization of intracranial vessels with MR angiography (MRA).

METHOD

Thirty-five subjects underwent two three-dimensional time-of-flight MRA sequences without and with MT and/or Gd. There were 14 MR angiograms without Gd or MT, 18 with MT only, 17 with Gd only, and 21 with both Gd and MT. On a projection image, a region of interest was drawn to delineate the arteries in the middle cerebral artery territory. The total area of blood vessels in the region of interest was calculated for each MR angiogram. Mean vessel areas for the four types of MRA were compared with analysis of variance.

RESULTS

MRA with either MT or Gd alone showed significantly more vessel area than MRA without either (p < 0.05). MRA with MT alone and MRA with Gd alone were not different from each other (p = 0.29). The improvement in vessel area measured by using MT and Gd together was significantly more than expected from the cumulative improvement of adding each alone (p < 0.05).

CONCLUSION

Combining MT and Gd synergistically improved the visualization of intracranial vessels on MRA.

Visualization and functional assessment of proximal and middle left anterior descending coronary stenoses in humans with magnetic resonance imaging

BACKGROUND

Coronary artery bypass grafting improves survival in patients with >70% luminal diameter narrowing of the 3 major epicardial coronary arteries, particularly if there is involvement of the proximal portion of the left anterior descending (LAD) coronary artery. Measurement of coronary flow reserve can be used to identify functionally important luminal narrowing of the LAD artery. Although magnetic resonance imaging (MRI) has been used to visualize coronary arteries and to measure flow reserve noninvasively, the utility of MRI for detecting significant LAD stenoses is unknown.

METHODS AND RESULTS

Thirty subjects (23 men, 7 women, age 36 to 77 years) underwent MRI visualization of the left main and LAD coronary arteries as well as measurement of flow in the proximal, middle, or distal LAD both at rest and after intravenous adenosine (140 microgram/kg per minute). Immediately thereafter, contrast coronary angiography and when feasible, intracoronary Doppler assessments of coronary flow reserve, were performed. There was a statistically significant correlation between MRI assessments of coronary flow reserve and (a) assessments of coronary arterial stenosis severity by quantitative coronary angiography and (b) invasive measurements of coronary flow reserve (P<0.0001 for both). In comparison to computer-assisted quantitative coronary angiography, the sensitivity and specificity of MRI for identifying a stenosis >70% in the distal left main or proximal/middle LAD arteries was 100% and 83%, respectively.

CONCLUSIONS

Noninvasive MRI measures of coronary flow reserve correlated well with similar measures obtained with the use of intracoronary Doppler flow wires and predicted significant coronary stenoses (>70%) with a high degree of sensitivity and specificity. MRI-based measurement of coronary flow reserve may prove useful for identification of patients likely to obtain a survival benefit from coronary artery bypass grafting.

Does potassium channel opening contribute to endothelium-dependent relaxation in human internal thoracic artery?

Opening of potassium channels can cause hyperpolarization and relaxation of vascular smooth muscle cells. The aim of this work was to investigate the contribution of potassium channel activation to vasorelaxation in internal thoracic artery taken from patients undergoing coronary artery bypass graft surgery. Relaxations to carbachol and sodium nitroprusside were studied in isolated rings of internal thoracic artery in the absence and presence of nitric oxide synthase inhibitors and potassium channel blockers. The nitric oxide synthase inhibitors Nomega-nitro-L-arginine methyl ester and NG-monomethyl-L-arginine abolished relaxations to carbachol. Relaxations to both carbachol and sodium nitroprusside were attenuated in the presence of raised extracellular potassium and the potassium channel blockers charybdotoxin, iberiotoxin and tetraethylammonium. Neither apamin nor glibenclamide modified relaxation. ODQ (1H-[1,2,4]oxadiazolol-[4,3a] quinoxalin-1-one), an inhibitor of soluble guanylate cyclase, abolished relaxation to carbachol in rings from some but not all subjects. These results suggest that potassium channel opening may make a small contribution to endothelium-dependent vasorelaxation in internal thoracic artery. The potassium channels had characteristics consistent with those of large-conductance calcium-dependent potassium channels.

Superoxide anion production is increased in a model of genetic hypertension: role of the endothelium

The hypothesis that the decreased nitric oxide (NO) availability observed in spontaneously hypertensive stroke-prone rats (SHRSP) is due to excess superoxide (O2-) was examined. O2- generation, measured by lucigenin chemiluminescence, was studied in 12- to 16-week male and female Wistar-Kyoto rats (WKY) and SHRSP. In addition, expression of the gene encoding endothelial NO synthase, the enzyme involved in NO generation, was investigated. O2- generation was increased in male and female SHRSP (4.11+/-0.24 and 3. 84+/-0.28 nmol O2-. min-1. mg-1 respectively) compared with their WKY counterparts and was significantly higher in male than female WKY (1.22+/-0.08 in males and 0.8+/-0.08 nmol O2-. min-1. mg-1 respectively) (SHRSP versus WKY P<0.0001, 95% CI -3.39, -2.51; male versus female WKY P=0.0029, 95% CI -0.67, -0.17). Removal of the endothelium by rubbing or addition of NO synthase inhibitors attenuated O2- generation in SHRSP but not WKY. In males, removal of the endothelium reduced O2- generation from 3.86+/-0.12 to 1.35+/-0. 08 nmol. min-1. mg-1 (P<0.0001, 95% CI 2.29, 2.81), whereas addition of L-NAME caused a reduction from 4.13+/-0.17 to 1.32+/-0.16 nmol. min-1. mg-1 (P<0.0001, 95% CI 2.36, 2.83). Similar reductions were observed in females. L-arginine had no significant effect, but tetrahydrobiopterin significantly decreased O2- generation in SHRSP from 4.04+/-0.11 to 2.36+/-0.40 nmol. min-1. mg-1 (P=0.0026, 95% CI 0.89, 2.44). Endothelial NO synthase mRNA expression was significantly greater in SHRSP than in WKY and in WKY males than in WKY females. These results show that O2- generation is increased in SHRSP and that the tissue and enzymatic sources of this excess O2- appear to be the endothelium and eNOS, respectively. The increase in O2- generation could explain the decreased availability of basal NO observed in this model of genetic hypertension.

Pharmacological characterisation of endothelium-dependent relaxation in human radial artery: comparison with internal thoracic artery

OBJECTIVE

The aim of this study was to investigate the contribution of nitric oxide/prostanoid-independent pathways to endothelium-dependent vasorelaxation in human conduit arteries.

METHODS

Rings of internal thoracic artery (ITA) and radial artery (RA) taken from patients undergoing coronary artery bypass graft surgery were suspended in 10-ml organ baths and relaxation to carbachol and bradykinin studied in the presence and absence of nitric oxide synthase (NOS) inhibitors and potassium channel blockers.

RESULTS

No significant relaxation to carbachol or bradykinin was observed in ITA after NOS inhibition. In contrast, in RA less than 40% attenuation of relaxation to carbachol or bradykinin was achieved with any of the NOS inhibitors. In the presence of 20 mM K+ relaxation to carbachol and bradykinin was inhibited by 28 +/- 9% and 42 +/- 9% while in the presence of L-NAME 200 microM + 20 mM K+ relaxation was inhibited by 66 +/- 6% and 70 +/- 4% respectively in this artery. Tetraethylammonium, glibenclamide, apamin and iberiotoxin had little effect on relaxation to carbachol but charybdotoxin alone and charybdotoxin plus apamin attenuated relaxation to carbachol by 23 +/- 4% and 49 +/- 9% in RA. In the presence of L-NAME 200 microM attenuation of these relaxations were increased to 60 +/- 4% and 78 +/- 4%.

CONCLUSION

In ITA relaxations to carbachol and bradykinin were mediated via nitric oxide. In contrast in RA, a conduit vessel of similar diameter, both nitric oxide-dependent and independent pathways appeared to contribute to vascular relaxation. This nitric oxide-independent relaxation involved opening of Ca2+ activated potassium channel(s). The existence of alternative pathways mediating endothelium-independent relaxation could be important under pathological conditions and may contribute to the long term survival of radial artery grafts.

Telemetry for cardiovascular monitoring in a pharmacological study: new approaches to data analysis

Radio-telemetry systems offer the ability to measure blood pressure and heart rate in experimental models of hypertension without the stress artifacts induced by some other methods. We therefore aimed to develop improved, nonparametric regression methods for radio-telemetry data and to use these to assess the effects of pharmacological interventions on cardiac and vascular hypertrophy in the stroke-prone spontaneously hypertensive rat. One control group and 5 groups treated either with losartan (alone or in combination with NG-nitro-L-arginine methyl ester [ L-NAME]), perindopril (also alone or in combination with L-NAME), or hydralazine plus hydrochlorothiazide were monitored for 4 weeks. Cardiac hypertrophy was assessed by the left ventricle plus septum weight to body weight ratio and vascular hypertrophy by flow-cytometry analysis of vascular smooth muscle cell polyploidy. Hemodynamic series were split into trend and cyclic components by the seasonal and trend decomposition procedure based on Loess and compared between groups by Loess regression modeling. Systolic and diastolic blood pressures were reduced systematically by losartan and perindopril (P<10(-10)) but to a lesser extent by hydralazine plus hydrochlorothiazide (P<10(-8)), and diurnal variation was reduced in the latter group (P<10(-6)). L-NAME significantly reduced the hypotensive effect only of losartan. Vascular and cardiac hypertrophy were significantly attenuated with losartan or perindopril, but were unchanged with other treatments. The new analysis proposed here identifies differential effects on trends and cyclic variation and associations with regression of end-organ damage for losartan and perindopril compared with hydralazine plus hydrochlorothiazide. The method offers a powerful tool for detailed investigation of radio-telemetry data.

Co-registration of cortical magnetic stimulation and functional magnetic resonance imaging

Functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) are noninvasive techniques recently used to investigate cortical motor physiology. However, these modalities measure different phenomena, and in studies of human motor control they have given inconsistent results. We have developed a reproducible technique which co-registers TMS and fMRI, using a frameless method. In four normal subjects, the TMS map and fMRI activation were present on the primary motor cortex contralateral to the target hand, with some extension into primary sensory cortex. fMRI activation alone was also present in the medial motor cortex bilaterally and in the sensorimotor cortex ipsilateral to the target hand. This technique allows a more comprehensive evaluation of the physiologic events involved in motor control.

Near-resonance saturation pulse imaging of the extraocular muscles in thyroid-related ophthalmopathy

PURPOSE

We examined the utility of near-resonance saturation pulse imaging (magnetization transfer [MT] and spin lock) in characterizing microstructural changes occurring in the extraocular muscles of patients with thyroid-related ophthalmopathy (TRO).

METHODS

Eight healthy volunteers and 10 patients with TRO were imaged using an off-resonance saturation pulse in conjunction with conventional spin-echo T1-weighted imaging at frequency offsets of 500, 1000, 1500, and 2000 Hz from water resonance. The relative contributions of MT and spin-lock excitation to image contrast at each frequency offset were estimated using a computer simulation model. Suppression ratios were calculated for the control and TRO groups from measurements obtained on two successive coronal sections in the widest portion of the inferior and medial rectus muscles bilaterally. A repeated measures analysis of variance and a parametric correlation analysis were performed to evaluate maximum cross-sectional area, MR-generated signal, and suppression ratios for the extraocular muscles examined.

RESULTS

Our computer model suggested that saturation of extraocular muscles was due to pure MT effects with our off-resonance pulse at 2000 and 1500 Hz, to a combination of MT and spin lock at 1000 Hz frequency offset, and, primarily, to spin-lock excitation at 500 Hz frequency offset. Suppression ratios for the extraocular muscles of the TRO patients were significantly lower than that observed for the control subjects at 1500, 1000, and 500 Hz frequency offset. This differential saturation effect was maximal at 500 Hz frequency offset, with mean suppression ratios for the inferior and medial rectus muscles of 27% for the healthy subjects and 20% for the TRO group.

CONCLUSION

Both MT and spin-lock contrast of the extraocular muscles in patients with TRO differ significantly from that observed in control subjects. Near-resonance saturation pulse imaging may enhance our understanding of the microstructural changes occurring in the extraocular muscles of these patients.

Endothelium dependent and independent relaxation of aortic rings from Watanabe heritable hyperlipidemic rabbits after exposure to free radical generating system

The effects of the xanthine oxidase/hypoxanthine free radical generating system on endothelium dependent and independent relaxation were compared in aortic rings from New Zealand white rabbits and heterozygous Watanabe heritable hyperlipidemic (WHHL) rabbits with mild atherosclerosis. Studies were carried out in young (3 months) and mature (18 months) animals. Plasma cholesterol levels were significantly higher in both 3 and 18 month WHHL animals. Endothelium independent relaxation to SNP did not differ between groups. However, the attenuation of relaxation to carbachol after xanthine oxidase/hypoxanthine treatment tended to be less in WHHL. This reached significance at 18 but not 3 months. We propose that this could be due to increases in levels of endogenous scavenger enzymes in these WHHL rabbits.

Left ventricular hypertrophy and arterial blood pressure in experimental models of hypertension

Cardiac hypertrophy in essential and experimental (genetic) hypertension have been initially attributed to increased pressure load. However, the level of blood pressure does not parallel the degree of cardiac hypertrophy, i.e., a complex relationship rather than a simple dose-response effect has to be suggested. Several non-haemodynamic factors which influence LV mass have been identified with genetic and neuro-hormonal influences playing a major role. The experimental strategies which have been used to highlight one or more of these influences include pharmacological studies of regression or prevention of LVH and studies designed to produce LVH de-novo in normotensive strains. All these studies while confirming an important role of haemodynamic factors also stress the major influence of the renin-angiotensin system and the inter-relationship between angiotensin II and nitric oxide. In contrast, genetic strategies, from simple co-segregation analysis to most complex genome scan studies, suggest the existence of "susceptibility genes" for LV hypertrophy, a finding which deserves further study in large collections of siblings and family groups with essential hypertension.

Vascular smooth muscle cell polyploidy and cardiomyocyte hypertrophy due to chronic NOS inhibition in vivo

To assess the vascular and cardiac response to NO (nitric oxide) synthase (NOS) blockade in vivo, Wistar-Kyoto rats (WKY) were treated for 3 wk with NG-nitro-L-arginine methyl ester (L-NAME; 10 mg.kg-1.day-1). L-NAME treatment induced hypertension that was associated with increased plasma renin activity. Flow cytometry cell cycle DNA analysis showed that aortic vascular smooth muscle cells (VSMC) from L-NAME-treated WKY had a significantly higher polyploid population compared with WKY controls. Using organ bath experiments, we have shown that aortic rings from L-NAME-treated WKY have an increased contractile response to phenylephrine and impaired relaxation to carbachol compared with control rings. NOS blockade in vivo caused a significant increase in cardiac and left ventricular hypertrophy. Northern mRNA analysis of the myocardium showed that L-NAME treatment caused reexpression of the fetal skeletal alpha-actin isoform without alterations in collagen type I expression, a pattern indicating true hypertrophy of the cardiomyocytes. These studies provide further insight to confirm that NO deficiency in vivo results in the development of vascular and cardiac hypertrophy.