Reference genome of Lumpfish Cyclopterus lumpus Linnaeus provides evidence of male heterogametic sex determination through the AMH pathway

Teleosts exhibit extensive diversity of sex determination (SD) systems and mechanisms, providing the opportunity to study the evolution of sex determination and sex chromosomes. Here we sequenced the genome of the Common Lumpfish (Cyclopterus lumpus Linnaeus), a species of increasing importance to aquaculture, and identified the SD region and master SD locus using a 70K SNP array and tissue-specific expression data. The chromosome-level assembly identified 25 diploid chromosomes with a total size of 572.89 Mb, a scaffold N50 of 23.86 Mb, and genome annotation predicted 21,480 protein-coding genes. Genome wide association analysis located a highly sex-associated region on chromosome 13, suggesting that anti-Müllerian hormone (AMH) is the putative SD factor. Linkage disequilibrium and heterozygosity across chromosome 13 support a proto-XX/XY system, with an absence of widespread chromosome divergence between sexes. We identified three copies of AMH in the Lumpfish primary and alternate haplotype assemblies localized in the SD region. Comparison to sequences from other teleosts suggested a monophyletic relationship and conservation within the Cottioidei. One AMH copy showed similarity to AMH/AMHY in a related species and was also the only copy with expression in testis tissue, suggesting this copy may be the functional copy of AMH in Lumpfish. The two other copies arranged in tandem inverted duplication were highly similar, suggesting a recent duplication event. This study provides a resource for the study of early sex chromosome evolution and novel genomic resources that benefits Lumpfish conservation management and aquaculture.

Outcomes after percutaneous coronary intervention (PCI) in patients with prior coronary artery bypass grafting (cabg)

Background

In patients with prior CABG requiring subsequent PCI there is uncertainty whether bypass grafts or native coronary arteries should be targeted.

Methods

We analysed data from 2,764 patients with prior CABG in the Melbourne Interventional Group registry (2005–2018), divided into two groups: those undergoing PCI to a native vessel (n=1,928) and those with PCI to a graft vessel (n=836).

Results

Patients with a graft vessel PCI were older, had more high-risk clinical characteristics (prior MI, heart failure, ejection fraction <50%, renal impairment, peripheral and cerebrovascular disease), and high-risk procedural features (ACC/AHA types B2/C lesions). However, patients in the native vessel group were more likely to have PCI to a chronic total occlusion. The majority of graft PCI were to saphenous vein grafts (84%), with 10% to radial and 6% to LIMA/RIMA grafts. Distal embolic protection devices were used in 30% of graft PCI. Patients with graft PCI had higher rates of no reflow (6.3% vs. 1.5%; p<0.001), coronary perforation (p=0.016) and inpatient stent thrombosis (p=0.028). However, 30-day mortality and major adverse cardiovascular and cerebrovascular events (MACCE) were similar. Unadjusted long-term mortality (median follow up 4.8 years) was higher in patients who had undergone a graft PCI (44% vs. 32%, p<0.001), but following Cox proportional hazards modelling, PCI vessel type was not a predictor of long-term mortality (HR 1.13; 95% CI 0.96–1.33, p=0.14).

Conclusions

Early clinical outcomes and risk-adjusted long-term mortality are similar for patients with prior CABG undergoing PCI to a native vessel or a bypass graft.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): The Alfred Hospital

Sex differences in pre-hospital analgesia and outcomes in patients presenting with acute coronary syndromes

Background

Opioid analgesia remains the mainstay of pain management in acute coronary syndromes (ACS). Significant sex differences persist in ACS presentation, management and outcomes, but the impact of sex-differences on pre-hospital pain management of ACS with opioids is unknown. There is increasing awareness of the importance of pre-hospital factors in ACS, as well as emerging concerns with opioid use impairing the gastrointestinal absorption of oral P2Y12 inhibitors.

Purpose

This study examined if sex-differences in pre-hospital pain scores, opioid administration and clinical outcomes exist in ACS patients.

Methods

Patients presenting with ACS via ambulance (2014–2018) that underwent percutaneous coronary intervention (PCI) were prospectively collected via the Victorian Cardiac Outcomes Registry (VCOR), the Melbourne Interventional Group (MIG), and linked to the Ambulance Victoria database. The primary outcome was 30-day major adverse cardiac events (MACE). Secondary outcomes were descriptive analyses of pre-hospital pain score, intravenous morphine equivalent analgesic dosing, plus predictors of MACE and Thrombolysis In Myocardial Infarction (TIMI) 0–1 flow pre-PCI using logistic regression.

Results

10,547 patients were included (female: 2,775 [26.3%]). Opioids were administered to 1,585 (57%) females and 5,068 (65%) males (p<0.001). Adjusted 30-day MACE was similar between opioid groups in both sexes (female: OR 1.21, CI 0.82–1.79, p=0.34; male: OR 0.89, 0.68–1.16, p=0.40). Median pain score at presentation was 6 (IQR 4,8) for both sexes. Median opioid dose was 2.5 mg (IQR 0,10) in females and 5 mg (IQR 0,10) in males (p<0.001), with similar pain relief achieved. Adjusted rates of TIMI 0–1 pre-PCI were higher in patients administered opioids (female: OR 2.83, CI 2.14–3.56, p<0.001; male: OR 2.95, CI 2.49–3.49, p<0.001).

Conclusions

Female patients undergoing PCI received less opioid analgesia, but no sex-differences in pre-hospital pain scores were seen. Opioid administration was associated with impaired antegrade flow in the culprit artery in both sexes, but not short-term MACE. Randomised trials evaluating the clinical implications of opioid administration in ACS with sex subgroup analyses are needed to guide clinical practice.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Melbourne Interventional GroupVictorian Cardiac Outcomes Registry

Trends in intra-aortic balloon pump use in cardiogenic shock in the post-SHOCK II trial era

Background

Myocardial infarction complicated by cardiogenic shock (MI-CS) has a poor prognosis, even with early revascularisation. Previously, intra-aortic balloon pump (IABP) use was thought to improve outcomes, but the SHOCK-II trial in 2012 found no survival benefit.

Purpose

This study aimed to determine the trends in IABP use in patients with MI-CS undergoing percutaneous intervention (PCI) over time and characteristics associated with use.

Methods

Between 2005–2018, patients presenting with MI-CS that underwent percutaneous coronary intervention (PCI) at a hospital participating in the Melbourne Interventional Group Registry were included. The primary outcome was the trend in IABP use over time. Secondary outcomes included mortality, 30-day MACCE (major adverse cardiovascular and cerebrovascular events) and predictors of outcome, determined via logistic regression.

Results

Of the 1,110 patients identified, IABP was used in 478 (43%). IABP was used more in patients with left main and left anterior descending culprit lesions (62% vs. 46%), lower ejection fraction (<35%; 18% vs. 11%), and pre-procedural inotrope use (81% vs. 73%), all p<0.05. IABP use was associated with higher inpatient bleeding (18% vs. 13%) and 30-day MACCE (58% vs. 51%), both p<0.05. The rate of MI-CS increased over time, but after 2012 there was a decline in IABP use (Figure 1). IABP use was a predictor of 30-day MACCE (OR 1.6, 95% CI 1.18–2.29, p=0.003). However, IABP was not associated with in-hospital, 30-day or long-term mortality (45% vs. 47%, p=0.44; 46% vs. 50%, p=0.25; 60% vs. 62%, p=0.39).

Conclusions

Consistent with the SHOCK II trial, IABP use is not associated with reduced short- or long-term mortality, but in this study was associated with increased short-term adverse events. IABP use is declining, but is still used in sicker patients with greater myocardium at risk, given limited alternatives.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Melbourne interventional group

P2654Impact of cultural and linguistic diversity on ischaemic time and clinical outcomes in patients undergoing percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI)

Background

Healthcare providers worldwide increasingly must face the challenge of providing care to culturally and linguistically diverse patients who may have limited proficiency in the primary working language of the country they are in. This language discordance may lead to delayed treatment and worse outcomes. The impact of limited English proficiency (LEP), in a predominantly English-speaking country like Australia, on time to reperfusion and outcomes following PCI for STEMI has not been previously studied.

Objective

Among patients undergoing PCI for STEMI, to compare baseline and procedural characteristics, time to reperfusion, and 30-day clinical outcomes in patients with LEP, compared to their English-proficient counterparts.

Method

We prospectively collected data on 7,721 patients undergoing PCI for STEMI between January 2013 and December 2017 who were enrolled in the state-wide multi-centre Victorian Cardiac Outcomes Registry. Data linkage to Department of Health administrative datasets was used to identify patients' primary spoken language. Patients who identified a language other than English as their primary spoken language were classified as having LEP. Patients' postcodes were used to identify socioeconomic status through Australian Government census data. The primary endpoint was 30-day major adverse cardiovascular events (MACE)

Results

Of the 7,721 patients included, 568 (7.4%) had LEP. Patients with LEP were more likely to be older, female, diabetic, have lower socioeconomic status and have severe renal impairment (all p<0.02). They were also more likely to present to a non-PCI capable hospital (p<0.001). Among primary PCI patients (n=5,385), symptom-to-balloon time was longer in the LEP group (237 [IQR 158–429] vs. 195 [IQR 141–326] minutes, p<0.001), driven mostly by longer symptom-to-door times (STDT) (150 [IQR 90–276] vs. 114 [IQR 75–215] minutes, p<0.001). LEP patients were also less likely to have a STDT≥120 minutes (48.8% vs. 41.7%, p-0.004). Patients with LEP had higher 30-day mortality (8.8% vs. 6.5%, p=0.04) and MACE (11.8 vs. 9.1%, p=0.04). They were also more likely to have severe left ventricular (LV) dysfunction post-STEMI (11.2% vs. 8.4%, p=0.003) and heart failure readmissions within 30 days of PCI (5.2% vs. 2.0%, p<0.001). On multivariate analysis, LEP was not an independent predictor of 30-day MACE (OR 1.27, 95% CI 0.82–1.95), but was an independent predictor of STDT≥120 minutes (OR 1.24, 95% CI 1.02–1.52).

Comparison of reperfusion times

Conclusion

Limited English-proficient patients with STEMI undergoing PCI tend to present later than their English-proficient counterparts and are more likely to have severe LV dysfunction and heart failure readmissions. LEP is an independent predictor of prolonged STDT but not 30-day MACE. This suggests that more effort needs to be placed in providing education in different languages to culturally and linguistically diverse patients, to encourage early presentation in the setting of STEMI.

P5290Impact of extreme obesity on long-term outcomes following percutaneous coronary intervention

Background

Obesity is a growing health concern worldwide, particularly in developed countries where there has been an unprecedented rise in the proportion of overweight and obese individuals in the population. Previous studies have reported a protective effect of obesity compared to normal BMI in patients undergoing percutaneous coronary intervention (PCI). However, it is unclear whether this effect extends to the extremely obese over long-term follow-up.

Objective

To determine whether an obesity paradox persists in contemporary PCI practice over long-term follow-up, and in particular to further evaluate the association between extreme obesity and long-term clinical outcomes after PCI.

Method

We prospectively collected data on 25,645 patients undergoing PCI between 1 January 2005 and 30 June 2017 who were enrolled in the statewide multi-centre Melbourne Interventional Group Registry. This registry collects data on all patients undergoing PCI at 6 academic tertiary hospitals. Patients were stratified by World Health Organization-defined BMI categories. Long-term mortality data was obtained by linkage to the National Death Index (NDI), a database that contains records of all deaths occurring in Australia. The primary endpoint was NDI-linked mortality. Median length of follow-up was 4.4 years (IQR 2.0–7.6 years).

Results

Of the study cohort, 24.6% had normal BMI (18.5–24.9 kg/m2), 0.9% were underweight (BMI <18.5 kg/m2) and 3.3% were extremely obese (BMI ≥40 kg/m2). As BMI increased, mean age decreased while the prevalence of diabetes increased (p<0.001). The proportion of females at both extremes of BMI. Procedural characteristics were similar across the groups although there was more radial access and less femoral access used with increasing BMI (p<0.001). In terms of secondary prevention therapy, underweight patients were significantly less likely to receive a beta blocker, ACE inhibitor and statins, compared to the other BMI groups. In-hospital, 30-day and long-term mortality were all highest for underweight patients (37.7%) and lowest for the moderately obese patients (BMI 35–40 kg/m2) (12.2%). After adjustment for age, comorbidities and presentation with cardiogenic shock, a U-shaped association between the different BMI categories and adjusted hazard ratio for long-term mortality was observed (Figure 1).

Figure 1

Conclusion

An obesity paradox is still apparent in contemporary practice with elevated BMI up to 35 kg/m2 associated with reduced long-term mortality after PCI. However, this protective effect appears not to extend to patients with extreme obesity. Factors behind this phenomenon are likely multifactorial and require further mechanistic and epidemiological studies.

Clopidogrel, prasugrel or ticagrelor in patients with acute coronary syndromes undergoing percutaneous coronary intervention

BACKGROUND

Guidelines recommend prasugrel or ticagrelor instead of clopidogrel in patients with acute coronary syndromes (ACS) undergoing percutaneous coronary interventions (PCI).

AIM

We sought to describe the trends in uptake of the newer agents and analyse the clinical characteristics and short-term outcomes of patients treated with clopidogrel, prasugrel or ticagrelor.

METHODS

We analysed the temporal trends of antiplatelet use since the availability of prasugrel (2009-2013) in patients with ACS from the Melbourne Interventional Group registry. To assess clinical characteristics and outcomes, we included 1850 patients from 2012 to 2013, corresponding to the time all three agents were available. The primary outcome was major adverse cardiovascular events (MACE). The safety end-point was in-hospital bleeding.

RESULTS

For the period of 2009-2013, the majority of patients were treated with clopidogrel (72%) compared with prasugrel (14%) or ticagrelor (14%). There was a clear trend towards ticagrelor by the end of 2013. Patients treated with clopidogrel were more likely to present with non-ST-elevation ACS, be older, and have more comorbidities. There was no difference in unadjusted 30-day mortality (0.9 vs 0.5 vs 1.0%, P = 0.76), myocardial infarction (2 vs 1 vs 2%, P = 0.52) or MACE (3 vs 3 vs 4%, P = 0.57) between the three agents. There was no difference in in-hospital bleeding (3 vs 2 vs 2%, P = 0.64).

CONCLUSION

Prasugrel and ticagrelor are increasingly used in ACS patients treated with PCI, predominantly in a younger cohort with less comorbidity. Although antiplatelet therapy should still be individualised based on the thrombotic and bleeding risk, our study highlights the safety of the new P2Y12 inhibitors in contemporary Australian practice.

Pre-treatment with dual antiplatelet therapy in patients with non-ST-segment elevation acute coronary syndromes undergoing percutaneous coronary intervention

BACKGROUND

Although dual antiplatelet therapy is the standard of care in non-ST-segment elevation acute coronary syndromes (NSTEACS), it remains unclear when a second antiplatelet agent should be initiated. We sought to assess the safety and efficacy of pre-treatment with clopidogrel in patients with NSTEACS undergoing percutaneous coronary intervention (PCI).

METHODS

We analysed baseline clinical and procedural characteristics of 6817 patients with NSTEACS who underwent PCI from the Melbourne Interventional Group registry from 2005 to 2012. Patients were included in the pre-treatment group if clopidogrel was administered prior to cardiac catheterisation. We assessed 30-day mortality, myocardial infarction (MI) and major adverse cardiovascular events. The safety endpoint was in-hospital bleeding.

RESULTS

Of the 6817 patients, only 2951 (43%) received pre-treatment with clopidogrel. Patients in the pre-treatment group were more likely to present with unstable angina (70.8% vs 68.2%, P = 0.02) and have a history of MI (35.6% vs 23.6%, P < 0.01) but were less likely to have PCI within 24 h of admission (17.2% vs 25.2%, P < 0.01). There was no difference between the groups in 30-day mortality (0.9% vs 1.4%, P = 0.06), MI (2.0% vs 2.2%, P = 0.52) or major adverse cardiovascular event (3.7% vs 4.2%, P = 0.25). There was no difference in bleeding complications (1.9% vs 1.9%, P = 0.94).

CONCLUSIONS

Pre-treatment with dual antiplatelet therapy in NSTEACS is not routine clinical practice in Australia. Pre-treatment appears safe but is not associated with improved short-term clinical outcomes.

Trends in door-to-balloon time and outcomes following primary percutaneous coronary intervention for ST-elevation myocardial infarction: an Australian perspective

BACKGROUND

Guidelines for patients with ST-elevation myocardial infarction include a door-to-balloon time (DTBT) of ≤90 min for primary percutaneous coronary intervention.

AIM

The aim of this study was to assess temporal trends (2006-2010) in DTBT and determine if a reduction in DTBT was associated with improved clinical outcomes.

METHODS

We compared annual median DTBT in 1926 STEMI patients undergoing primary percutaneous coronary intervention from the Melbourne Interventional Group registry. ST-elevation myocardial infarction presenting >12 h and rescue percutaneous coronary intervention was excluded. Major adverse cardiac events were analysed according to DTBT (dichotomised as ≤90 min vs >90 min). A multivariable analysis for predictors of mortality (including DTBT) was performed.

RESULTS

Baseline demographics, clinical and procedural characteristics were similar in the STEMI cohort across the 5 years, apart from an increase in out-of-hospital cardiac arrest (3.6% in 2006 vs 9.4% in 2010, P < 0.0001) and cardiogenic shock (7.7-9.6%, P = 0.07). The median DTBT (interquartile range) was reduced from 95 (74-130) min in 2006 to 75 (51-100) min in 2010 (P < 0.01). In this period, the proportion of patients achieving a DTBT of ≤90 min increased from 45% to 67% (P < 0.01). Lower mortality and major adverse cardiac event rates were observed with DTBT ≤90 min (all P < 0.01). Multivariable analysis showed that a DTBT of ≤90 min was associated with improved clinical outcomes at 12 months (odds ratio 0.48; 95% confidence interval 0.33-0.73, P < 0.01).

CONCLUSION

There has been a decline in median DTBT in the Melbourne Interventional Group registry over 5 years. DTBT of ≤90 min is associated with improved clinical outcomes at 12 months.

Ephedrine activates brown adipose tissue in lean but not obese humans

AIMS/HYPOTHESIS

Brown adipose tissue (BAT) activation increases energy consumption and may help in the treatment of obesity. Cold exposure is the main physiological stimulus for BAT thermogenesis and the sympathetic nervous system, which innervates BAT, is essential in this process. However, cold-induced BAT activation is impaired in obese humans. To explore the therapeutic potential of BAT, it is essential to determine whether pharmacological agents can activate BAT.

METHODS

We aimed to determine whether BAT can be activated in lean and obese humans after acute administration of an orally bioavailable sympathomimetic. In a randomised, double-blinded, crossover trial, we administered 2.5 mg/kg of oral ephedrine to nine lean (BMI 22 ± 1 kg/m²) and nine obese (BMI 36 ± 1 kg/m²) young men. On a separate day, a placebo was administered to the same participants. BAT activity was assessed by measuring glucose uptake with [¹⁸F]fluorodeoxyglucose and positron emission tomography-computed tomography imaging.

RESULTS

BAT activity was increased by ephedrine compared with placebo in the lean, but unchanged in the obese, participants. The change in BAT activity after ephedrine compared with placebo was negatively correlated with various indices of body fatness.

CONCLUSIONS/INTERPRETATION

BAT can be activated via acute, oral administration of the sympathomimetic ephedrine in lean, but not in obese humans.

A description of cattle movements in two departments of Buenos Aires province, Argentina

We present a descriptive analysis of cattle movement information retrieved from the Argentinean animal movement database for two departments in the province of Buenos Aires during 2004. For each quarter of the year (January to March, April to June, July to September, and October to December) we report the number of on- and off-farm movement events for the purpose of finishing. Our analyses show that the distribution of the number of finishing-related movement events per farm was skewed, with the majority of farms reporting at least 1 and less than 5% of farms of reporting greater than 15 finishing related movement events throughout the year. The frequency of finishing-related movement events varied over time, with a 1.2-1.8-fold increase in reported movement events from April to September, compared with the rest of the year. These analyses indicate that cattle movement patterns in these departments are dependent on the relative mix of constituent cattle enterprise types. Departments with a mixture of breeding and finishing enterprises behave as potential recipients and distributors of infectious disease, whereas departments comprised of primarily finishing enterprises are predominantly recipients of infectious disease, rather than distributors. Data integrity audits of the Argentinean animal movement database, on a regular or intermittent basis, should allow the presence of bias in these data to be quantified in greater detail.

Gut transport of a molybdenum/ascorbic acid complex

BACKGROUND

Relatively little work has been done on the absorption of trace elements in the mammalian small intestine. Recently, studies have demonstrated that a molybdenum/ascorbic acid complex has shown some promise as a potentially orally administered insulin-mimetic agent. However, the transport mechanism of the molybdenum/ascorbic acid complex is unknown. In this study we examine some aspects of the movement of the complex across the intestinal wall using measurements of elemental molybdenum as an indicator because it is not possible to measure the complex directly.

METHODS

Everted rat small intestine sacs were used to determine some aspects of the transport of the complex across the intestine. Intestinal sacs from five rats were incubated in a medium containing 1 g/L of the molybdenum complex. Sacs from a further five rats had 1 mmol/L of 2,4-dinitrophenol, a known inhibitor of oxidative phosphorylation, added to the incubation medium. In a second experiment, everted sacs from five rats were also incubated in media containing one of six concentrations of the molybdenum complex (0.5, 1, 2, 4, 8 or 10 g/L).

RESULTS

There was no significant difference between transport rates of groups with or without 2,4-dinitrophenol in the incubation medium, suggesting that the predominant mechanism of molybdenum transport is energy-independent. There was a significant positive, linear increase in the transport rate with increasing concentration of the molybdenum complex.

CONCLUSION

These data suggest that the predominant mechanism of this molybdenum/ascorbic acid complex transport in the small intestine is non-saturable and therefore not protein-mediated.

The Foundation and Launch of the Melbourne Interventional Group: A Collaborative Interventional Cardiology Project

The Melbourne Interventional Group (MIG) is a voluntary collaborative venture of interventional cardiologists practicing at 12 major public and private hospitals in Victoria, designed to record data pertaining to percutaneous coronary interventions (PCI) and perform long-term follow-up. The potential advantages of collaboration involve large-scale analysis of current interventional strategies (e.g. drug-eluting stents, evaluation of new technologies and cost-effective analysis), provide a basis for multi-centred clinical trials and allow comparison of clinical outcomes with cardiac surgery. The established registry documents demographic, clinical and procedural characteristics of consecutive patients undergoing PCI and permits analysis of those characteristics at 30 days and 12 months. The registry is co-ordinated by the Centre of Clinical Research Excellence (CCRE), a research body within the Department of Epidemiology and Preventive Medicine (Monash University, Melbourne). The eventual goal of MIG is to provide a contemporary appraisal of Australian interventional cardiology practice, with opportunities to improve in-hospital and long-term outcomes of patients with coronary artery disease.

Effects of the nitric oxide donor, sodium nitroprusside, on resting leg glucose uptake in patients with type 2 diabetes

AIMS/HYPOTHESIS

Nitric oxide (NO) has been implicated as an important signalling molecule in the contraction-mediated glucose uptake pathway and may represent a novel strategy for blood glucose control. The current study sought to determine whether acute infusion of the NO donor, sodium nitroprusside (SNP), increases leg glucose uptake at rest in patients with type 2 diabetes.

METHODS

Fifteen male patients with type 2 diabetes (aged 54+/-4 years, mean+/-SD) were entered into a randomised, cross-over design study, examining the effect of a 30-min intra-femoral infusion of SNP on leg glucose uptake. Comparison was made with a 30-min infusion of verapamil, titrated to elicit similar leg blood flow responses to SNP. Leg blood flow was measured by thermodilution in the femoral vein, and leg glucose uptake was calculated as the product of leg blood flow and the femoral arterio-venous (A-V) glucose concentration gradient.

RESULTS

The two drugs increased leg blood flow to a similar extent (p=0.50). Both leg A-V glucose concentration gradient (SNP 0.12+/-0.05, verapamil -0.06+/-0.04 mmol/l; mean+/- SEM, p=0.03) and leg glucose uptake (SNP 0.17+/-0.09, verapamil -0.09+/-0.06 mmol/min; p=0.03) were higher with the SNP treatment than with verapamil. These results occurred independently of any significant difference in plasma insulin concentration between drugs (p=0.56).

CONCLUSIONS/INTERPRETATION

Acute infusion of SNP resulted in greater glucose uptake relative to verapamil. NO may therefore be an important mediator of peripheral glucose disposal and a potential therapeutic target in patients with type 2 diabetes.

Effects of race and hypertension on flow-mediated and nitroglycerin-mediated dilation of the brachial artery

Black Americans have increased morbidity and mortality rates from cardiovascular disease, greater prevalence of hypertension, and altered responses to vasodilator medications compared with those of white Americans. Hypertension and black race have been linked to impaired vascular function in the microcirculation. To examine these effects and their interaction in the conduit vasculature, we examined vasomotor responses of the brachial artery by using high-resolution vascular ultrasound in 228 subjects (48% hypertensive, 54% black). Subjects had no history of diabetes mellitus and were matched for age and gender. Flow-mediated dilation (8.5+/-5.3% versus 11.7+/-6.3%, P<0.001) and nitroglycerin-mediated vasodilation (14.9+/-6.0 versus 18.5+/-7.8, P=0.003) were both impaired in hypertensive compared with normotensive individuals. Multivariate analysis identified higher systolic blood pressure (P=0.003) and larger baseline vessel (P<0.001) size as independent predictors of lower flow-mediated dilation. Race did not significantly influence flow-mediated dilation. In contrast, blacks had a greater vasodilator response to nitroglycerin compared with whites (17.7+/-7.5% versus 15.0+/-6.2%, respectively; P=0.02). By multivariate analysis, black race (P=0.004), smaller vessel size (P=0.001), lower serum glucose (P=0.02), lower systolic blood pressure (P=0.02), and lower serum total cholesterol (P=0.04) were independent predictors of higher nitroglycerin-mediated dilation. Thus, hypertension is associated with impaired NO-mediated vasodilation in the conduit brachial artery. Overall, race did not influence flow-mediated dilation, but black race was associated with an enhanced response to sublingual nitroglycerin. This later observation provides further evidence of racial differences in the responses to medical therapy that may be relevant to the treatment of patients with cardiovascular disease.

Acute hypertriglyceridemia is associated with peripheral vasodilation and increased basal flow in healthy young adults

Prior studies suggest that acute elevations in plasma triglycerides alter vascular tone and impair endothelial function. To investigate the relation between acute hypertriglyceridemia and vascular function, we examined the effects of high- and low-fat meals on brachial artery reactivity in 14 healthy volunteers. Flow-mediated dilation declined from 14.7 +/- 8.3% to 10.6 +/- 6.2% after the high-fat meal only (p <0.001), and this decline was associated with a 6% increase in baseline brachial artery diameter (3.50 +/- 0.74 mm to 3.70 +/- 0.81 mm, p <0.001), but not a decrease in the arterial diameter during hyperemia. The high-fat meal increased serum triglycerides and insulin by 94% and 438%, respectively. To investigate the effects of triglyceride elevation in isolation from hyperinsulinemia, we examined vascular responses to an intravenous infusion of a triglyceride emulsion in 28 subjects. Triglyceride emulsion increased serum triglycerides 197% but had no effect on serum insulin. Brachial artery diameter increased 4%, from 3.68 +/- 0.51 mm to 3.81 +/- 0.56 mm (p <0.05), and forearm flow increased 36%, reflecting vasodilation of forearm resistance vessels. Flow-mediated dilation and nitroglycerin-mediated dilation were unaffected. The triglyceride emulsion had no direct dilator effect on rabbit aortic tissue in vitro. In conclusion, acute hypertriglyceridemia is associated with vasodilation of conduit and resistance vessels in the arm and does not impair endothelial vasodilator function per se. The dilator effect is not insulin-dependent and does not appear to be a direct effect of triglycerides on vascular tissue.

Short- and long-term black tea consumption reverses endothelial dysfunction in patients with coronary artery disease

BACKGROUND

Epidemiological studies suggest that tea consumption decreases cardiovascular risk, but the mechanisms of benefit remain undefined. Endothelial dysfunction has been associated with coronary artery disease and increased oxidative stress. Some antioxidants have been shown to reverse endothelial dysfunction, and tea contains antioxidant flavonoids. Methods and Results-- To test the hypothesis that tea consumption will reverse endothelial dysfunction, we randomized 66 patients with proven coronary artery disease to consume black tea and water in a crossover design. Short-term effects were examined 2 hours after consumption of 450 mL tea or water. Long-term effects were examined after consumption of 900 mL tea or water daily for 4 weeks. Vasomotor function of the brachial artery was examined at baseline and after each intervention with vascular ultrasound. Fifty patients completed the protocol and had technically suitable ultrasound measurements. Both short- and long-term tea consumption improved endothelium- dependent flow-mediated dilation of the brachial artery, whereas consumption of water had no effect (P<0.001 by repeated-measures ANOVA). Tea consumption had no effect on endothelium-independent nitroglycerin-induced dilation. An equivalent oral dose of caffeine (200 mg) had no short-term effect on flow-mediated dilation. Plasma flavonoids increased after short- and long-term tea consumption.

CONCLUSIONS

Short- and long-term black tea consumption reverses endothelial vasomotor dysfunction in patients with coronary artery disease. This finding may partly explain the association between tea intake and decreased cardiovascular disease events.

Iron chelation improves endothelial function in patients with coronary artery disease

BACKGROUND

Some epidemiological studies have shown that increased iron stores are associated with increased cardiovascular events. Redox-active iron may contribute to lipid peroxidation, endothelial cell activation, and generation of reactive oxygen species (especially hydroxyl radical, via Fenton chemistry). Increased oxidative stress is associated with impaired action of endothelium-derived nitric oxide in patients with atherosclerosis.

METHODS AND RESULTS

To test the hypothesis that reducing vascular iron stores would reverse endothelial dysfunction, we examined the effects of the iron chelator deferoxamine (500 mg intra-arterially over 1 hour) on vasomotor function in forearm resistance vessels of patients with coronary artery disease by venous occlusion plethysmography. Patients with coronary artery disease had impaired endothelium-dependent vasodilation in response to methacholine compared with healthy control subjects (P<0.001). Deferoxamine infusion decreased serum iron levels (P<0.001). Deferoxamine improved the blood flow response to methacholine in patients with coronary artery disease (P<0.01 by 2-way repeated-measures ANOVA) but had no effect on the response to sodium nitroprusside. In normal volunteers, deferoxamine had no effect on the response to methacholine. The nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine abolished augmentation of the methacholine response associated with deferoxamine. The hydroxyl radical scavenger mannitol had no effect on the methacholine response.

CONCLUSIONS

Deferoxamine improved nitric oxide-mediated, endothelium-dependent vasodilation in patients with coronary artery disease. These results suggest that iron availability contributes to impaired nitric oxide action in atherosclerosis.

Effect of acute and chronic tea consumption on platelet aggregation in patients with coronary artery disease

Epidemiological studies suggest that tea consumption is associated with a decreased risk of cardiovascular events, but the mechanisms of benefit remain undefined. Platelet aggregation is a precipitating event in cardiovascular disease, and tea contains antioxidant flavonoids that are known to decrease platelet aggregation in vitro. To test the effect of tea consumption on platelet aggregation, we randomized 49 patients with coronary artery disease to either 450 mL of black tea or water consumed initially, followed by 900 mL of tea or water daily for 4 weeks in a crossover design. Ex vivo platelet aggregation in platelet-rich plasma was assessed in response to ADP and thrombin receptor-activating peptide at baseline and 2 hours and 4 weeks after beverage consumption. We observed dose-dependent platelet aggregation in response to each agonist, and neither relation was altered by acute or chronic tea consumption. Plasma flavonoids increased with acute and chronic tea consumption, indicating adequate absorption of tea flavonoids. In conclusion, these results demonstrate that acute and chronic black tea consumption does not affect ex vivo platelet aggregation in patients with coronary artery disease. These findings suggest that an effect of tea flavonoids on platelet aggregation is unlikely to be the explanation for the reduction in risk of cardiovascular events noted in epidemiological studies.

Agreement between coronary flow velocity reserve and stress echocardiography in intermediate-severity coronary stenoses

Visual and quantitative assessments of percent diameter stenosis on coronary angiography correlate poorly with functional testing, particularly in intermediate-severity (40%-70%) lesions, yet are frequently relied on to make decisions regarding revascularization. Coronary flow velocity reserve (CFVR) and relative CFVR (RCFVR) are promising methods for on-line functional assessment of lesion severity in the catheterization laboratory. We sought to determine the agreement between maximal, mean, and relative CFVR and stress echocardiography in intermediate-severity stenoses. The results of exercise or dobutamine stress echocardiography and CFVR measured by intracoronary Doppler were compared in 28 patients referred for assessment of intermediate-severity stenoses, using 15 patients with either angiographically normal coronary arteries or diameter stenoses > 70% as reference groups. CFVR was measured at least three times in response to a bolus of adenosine in the target vessel distal to the stenosis. RCFVR (target/normal vessel CFVR) was also measured in 27 patients. Maximal, mean (of three measures), and relative CFVR were calculated. CFVR > or = 2.0 and RCFVR > or = 0.75 were accepted as normal. A minority (29%) of patients in the intermediate-severity stenosis group had a positive test by either method. There was good to very good agreement between stress echocardiography and maximal CFVR (84%, kappa = 0.62, P < 0.0001) and RCFVR (81%, kappa = 0.59, P < 0.001) across the entire patient cohort, though in the intermediate subgroup concordance was only fair. Using the mean (of three measures of) CFVR for the same comparison improved the agreement in the intermediate subgroup to good (86%, kappa = 0.58, P = 0.002), and in the entire cohort the agreement was very good (88%, kappa = 0.74, P < 0.0001). There was only fair correlation between measures of CFVR and percent coronary stenosis. CFVR improved from 1.8 +/- 0.8 to 2.7 +/- 0.7 after percutaneous intervention (n = 12, P < 0.0001). These results suggest that there is good agreement between CFVR and stress echocardiography across a wide range of coronary lesion severity. The mean of three CFVR measurements distal to the target vessel stenosis increases diagnostic accuracy. Intracoronary Doppler flow velocity measurements at the time of cardiac catheterization may facilitate improved decision-making by providing the ability to assess the functional significance of coronary stenoses on-line.

Effect of anti-oxidant treatment and cholesterol lowering on resting arterial tone, metabolic vasodilation and endothelial function in the human forearm: a randomized, placebo-controlled study

1. The aim of the present study was to determine whether anti-oxidant therapy with vitamin E and/or cholesterol-lowering therapy with simvastatin would augment resting forearm blood flow (FBF) and metabolic vasodilation in response to exercise and improve endothelial function in young patients with hypercholesterolaemia. 2. Endothelium-dependent and -independent, nitric oxide (NO)-mediated vasodilation have been shown to be impaired in young, otherwise healthy subjects with hypercholesterolaemia. Recent experimental and clinical studies suggest that vascular function may be improved with anti-oxidant or cholesterol- lowering therapy, although these treatments may be synergistic. 3. We compared FBF at rest, in response to isotonic exercise, the endothelium-dependent vasodilator acetylcholine (ACh), the endothelium-independent vasodilator sodium nitroprusside (SNP) and the NO synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) in 26 young, otherwise healthy volunteers (mean (+/-SD) age 29+/-7 years; 14 female, 12 male) with hypercholesterolaemia, before and after 6 months treatment with vitamin E, simvastatin and/or placebo. Treatment was randomized, double-blinded in a 2 x 2 factorial design. Forearm blood flow was measured using venous occlusion plethysmography. 4. Vitamin E therapy increased plasma alpha-tocopherol from 39.5+/-9.6 to 75.7+/-33.8 micromol/L (P < 0.001). Simvastatin reduced total cholesterol from 6.9+/-1.7 to 4.9+/-0.8 mmol/L and low- density lipoprotein (LDL) from 4.8+/-1.7 to 3.0+/-0.7 mmol/L (both P < 0.001), although total and LDL-cholesterol also decreased slightly in the placebo group. Vitamin E increased resting FBF from 2.1+/-0.3 to 2.4+/-0.3 mL/100 mL per min (P = 0.04) and decreased resting forearm vascular resistance from 42.1+/-4.2 to 36.1+/-3.4 units (P = 0.01), but the reduction in resting FBF with L-NMMA was not affected. Vasodilation in response to isotonic exercise, ACh and SNP was similar before and after treatment in the placebo, vitamin E, simvastatin and in the combined vitamin E-simvastatin groups. NG-Monomethyl-L-arginine infusion reduced resting FBF and functional hyperaemia in response to exercise and these responses were not altered by treatment. 5. These data suggest that while vitamin E therapy augments resting FBF and reduces forearm vascular resistance in young hypercholesterolaemic subjects, these effects may not be via NO-dependent pathways. Metabolic vasodilation and responses to the NO-mediated vasodilators ACh and SNP were not favourably affected by anti-oxidant or cholesterol-lowering therapy, either alone or in combination.

Effect of ascorbic acid treatment on conduit vessel endothelial dysfunction in patients with hypertension

Hypertension is associated with low plasma ascorbic acid levels and impaired endothelial function. Recent evidence suggests that increased vascular oxidative stress contributes to the pathophysiology of endothelial dysfunction and hypertension. We recently showed that chronic oral ascorbic acid therapy lowers blood pressure in hypertensive patients. We hypothesized that it would also improve endothelial vasomotor function. In a randomized, double-blind, placebo-controlled study, we examined the effect of acute (2 g po) and chronic (500 mg/day for 1 mo) ascorbic acid treatment on brachial artery flow-mediated dilation in 39 patients with hypertension. Compared with 82 age- and gender-matched normotensive controls, these patients had impaired endothelium-dependent, flow-mediated dilation of the brachial artery [8.9 +/- 6.1 vs. 11.2 +/- 5.7% (SD), P < 0.04]. After therapy, plasma ascorbic acid concentrations increased acutely from 50 +/- 12 to 149 +/- 51 micromol/l and were maintained at 99 +/- 33 micromol/l with chronic treatment (both P < 0.001). As previously reported, chronic ascorbic acid therapy reduced systolic and mean blood pressure in these patients. However, acute or chronic ascorbic acid treatment had no effect on brachial artery endothelium-dependent, flow-mediated dilation or on endothelium-independent, nitroglycerin-mediated dilation. These results demonstrate that conduit vessel endothelial dysfunction secondary to hypertension is not reversed by acute or chronic treatment with oral ascorbic acid. The effects of this treatment on resistance vessel vasomotor function warrant further investigation.

Pharmacological concentrations of ascorbic acid are required for the beneficial effect on endothelial vasomotor function in hypertension

Increased production of superoxide anion may contribute to impaired bioactivity of endothelium-derived nitric oxide in hypertension. Ascorbic acid is capable of scavenging superoxide anion; however, experimental studies have shown that high physiological concentrations (>1 mmol/L) of ascorbic acid are required to prevent superoxide-mediated vascular dysfunction. To seek kinetic evidence that superoxide anion contributes to endothelial vasomotor dysfunction in human hypertension, we examined the effects of 2.4 or 24 mg/min ascorbic acid intra-arterial infusions on forearm blood flow responses to methacholine or sodium nitroprusside in 30 patients with hypertension and 22 age-matched controls. Endothelium-dependent vasodilation to methacholine was significantly impaired in the hypertensive patients, with a response to the highest dose of methacholine (10 microg/min) of 12.3+/-6.7 compared with 16.1+/-5.8 mL. min(-1). dL tissue(-1) in the controls (P<0.001). The response to sodium nitroprusside was equivalent in the 2 groups. Ascorbic acid at 24 mg/min significantly improved the forearm blood flow response to methacholine in hypertensive patients with a peak response of 16.1+/-7.1 mL. min(-1). dL tissue(-1) (P=0.001). This dose produced a cephalic vein ascorbic acid concentration of 3.2+/-1. 4 mmol/L. In contrast, ascorbic acid at 2.4 mg/min had no effect on the methacholine response. Ascorbic acid at both doses had no effect on the vasodilator response to sodium nitroprusside in hypertensive patients or the methacholine response in the controls. These results agree with the predicted kinetics for superoxide anion-mediated impairment of endothelium-derived nitric oxide action. Thus, superoxide anion may contribute to impaired endothelium-dependent vasodilation in patients with hypertension.

Long-term oestrogen therapy is associated with improved endothelium-dependent vasodilation in the forearm resistance circulation of biological males

1. The aim of the present study was to determine the effects of long-term oestrogen on resistance vessel reactivity in biological males. 2. Recent studies have demonstrated that long-term oestrogen therapy favourably alters the lipid profile and improves vasodilator function in the conduit arteries of biological males. Whether a similar benefit is exerted on the resistance circulation is not known. Therefore, we examined the effects of long-term oestrogen therapy on skeletal muscle resistance vessel function in biological males and the potential mechanisms by which it may exert its effects. 3. Forearm blood flow (FBF) and resistance were compared in 15 male-to-female transsexuals being prescribed oestrogen, with 14 age-matched healthy males, at rest and in response to the endothelium-dependent nitric oxide (NO) vasodilator acetylcholine (ACh), the endothelium-independent but NO-mediated vasodilator sodium nitroprusside (SNP), the endothelium-independent and non-NO-mediated vasodilator verapamil (VER) and the endothelium-independent vasoconstrictor phenylephrine (PE). 4. Basal blood flows were similar in the two groups. However, the male-to-female transsexuals had a significant upward and leftward shift in FBF responses to ACh compared with males, with a 52% increase in FBF responses at the highest dose of ACh used. Forearm blood flow in transsexuals rose from a mean (+/- SEM) baseline level of 3.02 +/- 0.25 to a maximum of 19.5 +/- 2.59 mL/min per 100 mL forearm tissue (compared with 3.24 +/- 0.41 and 9.43 +/- 1.97 mL/min per 100 mL forearm tissue, respectively, in males) with the highest dose of ACh (+2.73 micrograms/min per 100 mL; P < 0.0005). Forearm vascular resistance was also significantly reduced in transsexuals compared with males (P < 0.05). Vasodilator responses to SNP, VER and PE were similar in both groups. 5. There were no differences observed in total cholesterol and low-density lipoprotein-cholesterol levels. However, male-to-female transsexuals had 20% higher high-density lipoprotein-cholesterol levels compared with males (1.57 +/- 0.11 vs 1.26 +/- 0.08 mmol/L, respectively; P < 0.05) and 47% higher triglyceride levels (P < 0.005). Serum testosterone levels (an index of oestrogen therapy) was a predictor of responses to endothelium-dependent vasodilation (rs = -0.50; P < 0.01). 6. Long-term oestrogen therapy enhances endothelium-dependent vasodilation in the skeletal muscle microcirculation of biological males. The effects appear to be selective because endothelium-independent vasodilation and vasoconstriction are not altered.

Treatment of hypertension with ascorbic acid

In a randomised, double-blind, placebo-controlled study we showed that treatment of hypertensive patients with ascorbic acid lowers blood pressure. Further studies of ascorbic acid to treat hypertension, with clinical endpoints, are warranted.

Wood's lamp utility in the identification of semen

BACKGROUND

The accurate detection of semen is critical to forensic, medical, and legal personnel. The Wood's lamp (WL) emits ultraviolet light (UVL) and has been identified as useful in rape evaluations because it is purported to cause semen to fluoresce. This study was intended to determine if semen can be distinguished from other products by WL analysis.

METHODS

Investigators reviewed the previous training and frequency of use of the WL by emergency medicine and pediatric emergency medicine physicians at 2 medical centers. The participants were asked to use a WL to distinguish between a semen sample (<6 hours old) and 13 commonly used products. Next, 29 semen samples were collected and evaluated under high-power microscopy and under UVL.

RESULTS

A total of 41 physicians participated in the study (68% male). The number of years practicing in an emergency setting spanned from.3 to 25 years with a mean of 7. 1 years. A total of 51% of participants trained in emergency medicine, 23% in pediatrics and pediatric emergency medicine. A total of 22% reported formal training in the collection of forensic evidence. A total of 62% of the physicians believed they have identified semen in the past; one third felt they could differentiate semen from other products under UVL. None of the 41 physicians were able to differentiate semen from other products using a WL. Moreover, the semen samples used for the study did not fluoresce under WL analysis. None of the 29 semen samples fluoresced whether wet or dry. The medicaments most commonly mistaken for semen were A&D ointment (Cardinal Health, Inc, Dublin, OH), Surgilube (Division of Atlanta, Inc, Melville, NY), Barrier cream (Carrington Laboratories, Inc, Irving, TX), and bacitracin (Division of Atlanta, Inc, Melville, NY).

CONCLUSIONS

Participating physicians were unable to distinguish between semen and other common products, using the WL. Although the WL has been purported to be a useful tool as a screening device for the detection of seminal stains, the investigators have found it to be unreliable. Semen, previously reported to fluoresce under WL analysis, does not appear to do so. The correct identification of semen may be complicated by the presence of previously existing ointments and creams, some of which may be iatrogenically introduced (ie, Surgilube).

Estrogen improves acetylcholine-induced but not metabolic vasodilation in biological males

We have previously shown that chronic estrogen therapy improves endothelium-dependent vasodilation in the resistance vessels of biological males. Whether this is nitric oxide (NO) mediated and whether estrogen improves metabolic vasodilation is unknown. Resting forearm blood flow (FBF), ACh-induced vasodilation, and functional hyperemic blood flow (exercise) were assessed before and after the inhibition of NO with N(G)-monomethyl-L-arginine (L-NMMA) in 15 male-to-female transsexuals prescribed estrogen and in 14 age-matched males. Resting FBF was similar in the two groups and was similarly (P = 0.44) but significantly reduced by 48% after infusion of L-NMMA (P < 0.0001). The ACh dose-response relationship was shifted upward and to the left in the transsexual compared with the male group (P < 0.01). After the inhibition of NO, however, the difference in the ACh dose-response curve between the two groups was abolished (P = 0.15). Peak functional hyperemic blood flow was similar for the two groups (P = 0.94). L-NMMA produced a significant (P < 0.01) but similar (P = 0.64) reduction in peak hyperemia in the two groups. The volume of blood repaid to the forearm 1 and 5 min after exercise was also reduced by L-NMMA (P < 0.0001); however, there were no differences between the two groups. This suggests that ACh-mediated NO-dependent vasodilation may be more sensitive to the effects of chronic estrogen than exercise-induced vasodilation. Long-term estrogen does not appear to improve exercise-induced metabolic vasodilation in biological males, despite the fact that NO contributes to this process.

Contribution of vasodilator prostanoids and nitric oxide to resting flow, metabolic vasodilation, and flow-mediated dilation in human coronary circulation

BACKGROUND

Endothelial dysfunction is associated with atherosclerosis and may contribute to ischemic syndromes. We assessed the contribution of endothelium-derived nitric oxide (NO) and vasodilator prostanoids to resting blood flow, metabolic vasodilation, and flow reserve in the human coronary circulation.

METHODS AND RESULTS

Coronary hemodynamics were assessed before and after inhibition of vasodilator prostanoids and NO with intracoronary aspirin (acetylsalicylic acid [ASA]) and N(G)-monomethyl-L-arginine (L-NMMA), respectively. Angiographically smooth or mildly irregular vessels, with normal adenosine-induced coronary flow reserve, were studied in 25 patients undergoing clinically indicated procedures. Coronary blood velocity was measured by Doppler flow wire, and coronary blood flow (CBF) was calculated. ASA reduced resting conduit vessel diameter by 11% (P = 0.003) and CBF by 27% (P = 0.008) and increased coronary vascular resistance (CVR) by 24% (P<0.0001). ASA attenuated pacing-induced hyperemia by 28% (45.0+/-4.6 versus 32.6+/-3.4 mL/min, P = 0.005) and increased minimum CVR by 39% (2.8+/-0.3 versus 3.9+/-0.5 mm Hg x mL(-1) x min(-1), P = 0.007). L-NMMA reduced resting conduit vessel diameter by 9% (P = 0.05) and CBF by 20% (P = 0.08) and increased CVR by 19% (P = 0.03). L-NMMA attenuated pacing-induced hyperemia by 20% (42.4+/-5.1 versus 34.1+/-3.4 mL/min, P = 0.04) and increased minimum CVR by 33% (2.9+/-0.4 versus 3.8+/-0.5 mm Hg x mL(-1) x min(-1), P = 0.02). ASA (7.7+/-2.3% versus -1.6+/-3.2%, P = 0.06) and L-NMMA (12.1+/-3.9% versus 0.0+/-2.9%, P = 0.02) abolished pacing-induced conduit vessel flow-mediated dilation. Conclusions-Tonic release of vasodilator prostanoids and NO contributes to resting conduit and resistance vessel tone and to peak functional hyperemia and flow-mediated dilation after metabolic stimulation. This underscores the importance of normal endothelial function for metabolic vasodilation and suggests that it may be a key mechanism for preventing myocardial ischemia in coronary artery disease.

Metabolic vasodilation in the human forearm is preserved in hypercholesterolemia despite impairment of endothelium-dependent and independent vasodilation

OBJECTIVE

Hypercholesterolemia has been shown to impair endothelium-mediated, nitric oxide (NO)-dependent responses to acetylcholine (ACh), serotonin, substance P and flow-mediated dilation. We have recently shown that NO contributes to metabolic vasodilation in the human forearm. We sought to determine whether metabolic vasodilation is impaired in healthy subjects with hypercholesterolemia.

METHODS

We compared the forearm blood flow (FBF) responses to isotonic exercise, ACh and the endothelium-independent vasodilator sodium nitroprusside in young, otherwise healthy volunteers with hypercholesterolemia and controls before and after the NO inhibitor NG-monomethyl-L-arginine (L-NMMA). FBF was measured using venous occlusion plethysmography. Hypercholesterolemic (n = 20) and control (n = 20) subjects were age- and gender-matched.

RESULTS

Total cholesterol (6.9 +/- 0.3 vs. 4.6 +/- 0.1 mmol/l, P < 0.0001), low density lipoprotein (4.9 +/- 0.4 vs. 2.7 +/- 0.1 mmol/l, P < 0.001) and triglyceride (1.3 +/- 0.2 vs. 0.8 +/- 0.1 mmol/l, P = 0.005) levels were higher in the hypercholesterolemic group. Basal FBF and resistance were similar in the two groups. Hypercholesterolemia impaired the peak FBF response to ACh (11.1 +/- 1.9 vs. 17.6 +/- 2.2 ml/100 ml/min, P = 0.03), and reduced the peak response to sodium nitroprusside (6.0 +/- 0.4 vs. 8.1 +/- 0.6 ml/100 ml/min, P < 0.01). However, hypercholesterolemia did not affect peak hyperemic FBF (13.1 +/- 1.0 vs. 13.2 +/- 1.0 ml/100 ml/min, P = 1.0) or the FBF volume repayment during the 1 or 5 min after exercise. Resting FBF was reduced by L-NMMA to a similar degree (by 33% vs. 40%, P = 0.17) in both groups. Although L-NMMA reduced peak hyperemic FBF (by 16% vs. 17%, P = 0.93) and the volume repaid after exercise in both groups, there were no differences between the two groups.

CONCLUSIONS

Exercise-induced metabolic vasodilation is in part dependent on NO release. Hypercholesterolemia impairs NO-mediated vasodilation, but is not associated with a reduction in exercise-induced hyperemia. This may indicate that multiple compensatory mechanisms are operative in skeletal muscle metabolic vasodilation.

Acute administration of 17beta-oestradiol does not improve endothelium-dependent vasodilatation in young men

Studies have recently demonstrated that long-term oestrogen therapy improves endothelium-dependent and endothelium-independent vasodilatation in the conductance vessels of biological males. We sought to determine if an acute single dose of oestrogen might similarly improve vasodilator function in young males. In a randomized, double-blind, placebo-controlled, crossover study, we compared the effects of 1 mg of sublingual 17beta-oestradiol (E(2)) and placebo on endothelium-dependent and endothelium-independent vasodilatation in the brachial artery using a non-invasive ultrasound technique. We recruited 30 young males based on a power calculation. Neither acute sublingual oestrogen nor placebo affected flow-mediated vasodilatation [5.32+/-0.78% and 5.28+/-0.60% respectively (mean+/-S.E.M.), P=0.94]. Responses to nitroglycerine were similar after oestrogen or placebo (16.01+/-0.86% and 15.29+/-1. 19%, P=0.47). Basal blood flow and flow during reactive hyperaemia did not differ after oestrogen or placebo. Heart rate and blood pressure were similar during both treatment phases of the study. The absolute change in serum oestradiol levels was greater after the oestrogen treatment phase than after placebo (1509+/-87 versus -13+/-4 pmol/l, P<0.0001). Despite achieving supra-physiological oestradiol levels, the acute administration of sublingual E(2) does not appear to improve endothelium-dependent or endothelium-independent vasodilatation, at least acutely, in the brachial artery of young males. In keeping with our previous study, these data suggest that a period of oestrogen 'priming' (possibly to induce receptor-mediated nitric oxide synthesis) may be required to yield an improvement in vascular function in males.

Mothers with histories of domestic violence in a pediatric emergency department

OBJECTIVE

To determine the prevalence of domestic violence against mothers in a pediatric emergency department and the relationship of their children to the abusers.

DESIGN

Cross-sectional survey of a convenience sample of mothers seeking treatment for their children.

SETTING

An urban pediatric emergency department.

PARTICIPANTS

A total of 157 mothers with children <3 years of age. Women were excluded if older children or partners were present.

RESULTS

A total of 52% of women reported histories of adult physical abuse, 21% reported adult sexual abuse, and 28% reported childhood sexual abuse. A total of 10% of women were in abusive relationships in the past year. Victims of adult physical abuse were more likely to report histories of adult sexual abuse (relative risk [RR]: 4.93) or childhood sexual abuse (RR: 3.13). Intimate partners perpetrated 67% of physical abuse and 55% of sexual abuse. Relatives perpetrated 66% of childhood sexual abuse. Women who revealed histories of childhood sexual abuse were more likely to report adult sexual abuse (RR: 4. 93). A total of 40% of the perpetrators of adult physical abuse, 73% of the perpetrators of past year physical abuse, and 10% of the perpetrators of adult sexual abuse had regular contact with their victims' children. Health care providers screened only 21% of the women for past violence. Victims of domestic violence were no more likely to have been screened than those without histories of physical or sexual abuse.

CONCLUSIONS

Mothers of young patients in a pediatric emergency department are often victims of domestic violence. Perpetrators are often close relatives and thus place the victims' children at risk for abuse and for the psychological trauma of witnessing violence. Given the prevalence of domestic violence, families may benefit from routine violence screening and interventions in pediatric emergency departments.

Intravenous catheter blood cultures: utility and contamination

OBJECTIVE

In pediatrics, blood cultures (BCs) are often drawn as intravenous (IV) catheters are placed. This routine minimizes the number of painful and often difficult punctures a child must undergo but results in the discarding of multiple BC bottles when these cultures are later determined to be unnecessary. If the contamination rate of BCs drawn through an indwelling IV did not exceed the contamination rate of BCs drawn at the time of IV placement, BCs could be drawn from the IV without subjecting the patient to another venipuncture. This study was done to compare the contamination rates of BCs drawn by these two methods. Additionally, we sought to determine if the collection of two BCs enhances pathogen recovery.

METHODS

Prospective comparison of contamination and bacteremia rates of BCs drawn by two different methods: the first BC was drawn at the time of IV line placement and the second BC was drawn from the previously placed IV at a later time. Setting. Urban pediatric emergency department with an annual census of 40 000.

PARTICIPANTS

One thousand five hundred sixty-four patients between the ages of 3 days and 22.1 years. The median age was 2.2 years. Sixty-four patients were excluded because we were unable to draw the second BC. Forty-six percent of eligible patients (n = 690) were girls.

RESULTS

Fifty-seven (1.9%) of 3000 grew contaminants: 27 in the first and 30 in the second BC for contamination rates of 1.8% and 2.0%. Thirty-eight (1.3%) of 3000 BCs grew pathogens: 24 represent 12 patients with growth in two out of two cultures and 14 represent 14 patients with growth in one out of two cultures. Pathogen rates were 1.1% (16/1500) with one BC per patient and 1.7% (22/1500) with two BCs per patient.

CONCLUSIONS

There is no difference in the contamination rates of two BCs drawn from the same site at two different times. The collection of two BCs per patient may enhance pathogen recovery.

Relative contribution of vasodilator prostanoids and NO to metabolic vasodilation in the human forearm

Although many factors are thought to contribute to the regulation of metabolic vasodilation in skeletal muscle vasculature, recent interest has focused on the role of the endothelium. We examined the relative roles of nitric oxide (NO) and of vasodilator prostanoids in the control of metabolically induced functional hyperemia in the forearm of humans. In 43 healthy volunteers [24 +/- 5 (SD) yr] we assessed resting and functional hyperemic blood flow (FHBF) in response to 2 min of isotonic forearm exercise before and after inhibition of NO and/or vasodilator prostanoid production with intra-arterial NG-monomethyl-L-arginine (L-NMMA, 2 mg/min) and aspirin (ASA, 3 mg/min), respectively. Blood flow was measured using venous occlusion plethysmography. L-NMMA and ASA decreased resting forearm blood flow by 42% (P < 0.0001) and 23% (P < 0.0001), respectively, whereas infusion of ASA followed by L-NMMA reduced flow by a further 24% (P < 0.05). L-NMMA reduced peak FHBF by 18% [from 13.9 +/- 1.0 to 11.4 +/- 1.1 (SE) ml. 100 ml forearm-1. min-1, P = 0.003] and the volume "repaid" after 1 and 5 min by 25% (8.9 +/- 0.7 vs. 6.7 +/- 0.7 ml/100 ml, P < 0.0001) and 37% (26.6 +/- 1.8 vs. 16.8 +/- 1.6 ml/100 ml, P < 0.0001). ASA similarly reduced peak FHBF by 19% (from 14.5 +/- 1.1 to 11.8 +/- 0.9. 100 ml forearm-1. min-1, P < 0.001) and the volume repaid after 1 and 5 min by 14% (7.5 +/- 0. 6 vs. 6.4 +/- 0.6 ml/100 ml, P = 0.0001) and 20% (21.2 +/- 1.5 vs. 16.9 +/- 1.5 ml/100 ml, P < 0.0001), respectively. The coinfusion of ASA and L-NMMA did not decrease FHBF to a greater extent than either agent alone. These data suggest that endothelium-derived NO and vasodilator prostanoids contribute to resting blood flow and metabolic vasodilation in skeletal muscle vasculature in healthy humans. Although these vasodilator mechanisms operate in parallel in exercise-induced hyperemia, they appear not to be additive. Other mechanisms must also be operative in metabolic vasodilation.

Continuous release of vasodilator prostanoids contributes to regulation of resting forearm blood flow in humans

Continuous release of nitric oxide contributes to the maintenance of resting tone in the human forearm and coronary circulations; however, evidence for a similar role of vasodilator prostanoids such as prostacyclin is lacking. We examined whether continuous release of prostacyclin contributes to basal forearm blood flow. Flow was measured using venous occlusion plethysmography in 38 healthy volunteers [mean age 21.3 +/- 2.5 yr (+/- SD); 13 female, 25 male] at rest, after administration of three incremental intra-arterial infusions of either the cyclooxygenase inhibitor aspirin or placebo, and before and after administration of the endothelium-dependent and -independent dilators acetylcholine (30 micrograms/min) and nitroprusside (1 microgram/min). To assess the effect of aspirin on the production of prostacyclin, plasma 6-keto prostaglandin F1 alpha (6-keto-PGF1 alpha; the stable metabolite of prostacyclin) was measured by simultaneous arterial and venous sampling. Aspirin produced a time- and dose-dependent reduction in forearm blood flow, resulting in a 32% decrease at the highest dose. The effect was maximal after 10 min. Flow at rest and after aspirin doses of 1, 3, and 10 mg/min was 2.6 +/- 0.2, 2.3 +/- 0.2, 2.1 +/- 0.2, and 1.8 +/- 0.2 ml.100 ml forearm tissue-1.min-1, respectively (means +/- SE, P < 0.001). Commensurate with these data, the net forearm production of 6-keto-PGF1 alpha was 52.9 +/- 16.4, 11.7 +/- 8.6, 18.7 +/- 8.5, and 12.0 +/- 12.5 pg.100 ml forearm tissue-1.min-1 for the respective doses (P = 0.04). No time-dependent reduction in flow was seen in subjects with vehicle infusion. Aspirin did not affect the responses to acetylcholine or nitroprusside. These data suggest that continuous release of prostacyclin plays a role in the maintenance of resting forearm blood flow. There appears to be a direct link between the reduction in flow with aspirin and inhibition of prostacyclin production.

Long-term estrogen therapy improves vascular function in male to female transsexuals

OBJECTIVES

This study sought to examine the effects of long-term estrogen therapy on vascular function in male to female transsexuals and to compare the findings with those observed in men and premenopausal women.

BACKGROUND

Gender differences in coronary artery disease have largely been attributed to the beneficial effects of estrogen on vascular function and plasma lipids in women. However, the effects of estrogen on the male vasculature have not been widely studied.

METHODS

We compared the effects of estrogen on vascular function in 14 male to female transsexuals, 14 age-matched men and 15 premenopausal women. Flow-mediated vasodilation and response to nitroglycerin were assessed in the brachial artery using noninvasive ultrasound.

RESULTS

Flow-mediated vasodilation was similar in transsexuals and women but greater than that in men ([mean +/- SE] 11.5 +/- 1.3% and 9.4 +/- 1.1% vs. 5.2 +/- 1.0% respectively, p < 0.005). Responses to nitroglycerin were also greater in transsexuals and women than in men (21.6 +/- 1.7% and 21.0 +/- 0.9% vs. 14.5 +/- 1.2%, respectively, p = 0.0005). These differences persisted even after adjusting for vessel size. Despite similar total cholesterol levels, transsexuals had high density lipoprotein cholesterol levels similar to those in women and greater than those observed in men (1.76 +/- 0.12 and 1.82 +/- 0.11 mmol/liter vs. 1.35 +/- 0.07 mmol/liter, respectively, p < 0.005). Moreover, triglyceride levels were greater in transsexuals than in men and women, and low density lipoprotein cholesterol (LDL-C) particle size was smaller (25.7 +/- 0.2 nm vs. 26.2 +/- 0.1 and 26.6 +/- 0.1 nm, respectively, p = 0.0001). Serum testosterone (an index of estrogen therapy in transsexuals) was markedly suppressed in transsexuals and similar to that in women. Univariate analysis revealed that there was a strong inverse correlation between serum testosterone and flow-mediated vasodilation (r(s) = -0.48, p < 0.005). Multivariate analysis revealed that the best combination of predictors of flow-mediated vasodilation was serum testosterone, vessel size and LDL-C (R2 = 0.3, p < 0.005).

CONCLUSIONS

Long-term estrogen therapy appears to improve vascular function in male to female transsexuals and occurs despite higher triglyceride levels and the presence of small, dense LDL-C. The beneficial effects of estrogen are not gender specific or solely mediated through endothelium-derived nitric oxide.

Violence against women: provider barriers to intervention in emergency departments

OBJECTIVE

To determine: 1) provider behavior in screening for domestic violence (DV) and sexual assault (SA); 2) provider training in DV and SA; 3) provider knowledge of available protocols for DV and SA; and 4) provider perception of barriers to intervention.

METHODS

Anonymous, structured surveys were distributed to physicians, nurses, and social workers at an adult ED trauma center, an affiliated pediatric ED, and a women's urgent care center between July and September 1995.

RESULTS

Of 207 staff members (59%) responding, 54% and 68% indicated that they never/rarely screen for DV or SA, respectively. Thirty-five percent had received no DV training and 27% had received no SA training. Thirty-one percent of the staff had knowledge of existing protocols for DV and 63% had knowledge of existing protocols for SA. Providers trained in DV were more likely to screen for DV (RR 1.5, 95% CI 1.27-1.92, p < or = 0.001) and SA (RR 1.49, 95% CI 1.24-1.79, p < or = 0.0018), and providers trained in SA were more likely to screen for SA (RR 1.32, 95% CI 1.13-1.54, p = 0.0019) and DV (RR 1.35, 95% CI 1.13-1.60, p = 0.0007). Barriers that the majority of staff experienced in the care of DV/SA victims included: frustration that the victim would return to an abusive partner, concerns about misdiagnosis, lack of time, personal discomfort, reluctance to intrude into familial privacy, and lack of 24-hour social service support.

CONCLUSION

Providers surveyed had received little training in and rarely screen for violence, and there are a range of personal and institutional barriers impeding intervention with victims of SA and DV. Institutional changes to enhance training and support providers working in the front line of this epidemic may improve services for victims of violence.

Use of an enzyme-linked immunosorbent assay for detection of infection with pseudorabies virus on a herd basis

The use of an ELISA that can differentiate between swine infected with pseudorabies virus (PRV) and swine vaccinated with a specific PRV vaccine was evaluated on an individual and herd basis, and a system for interpreting ELISA results on a herd basis was developed. In 17 herds, recently introduced replacement gilts, seronegative for PRV, were vaccinated with a thymidine kinase- and glycoprotein X (gpX)-deleted vaccine. After vaccination, blood samples were collected from these gilts approximately every 1 to 2 months for up to 19 months. Serum samples were analyzed for antibodies to gpX antigen, using a commercially available ELISA kit according to the manufacturer's protocol. Herd status was determined as positive, suspect, or negative, according to the serum sample:negative control (S:N) values of the samples collected from the herd. From the 17 herds, 130 evaluations were performed. On 49 (38%) of the 130 herd evaluations, 1 or more gilts had suspect test results. Additional testing was required in 19 (39%) of these 49 herd evaluations to determine the PRV infection status of the herd. Status of herds having gilts with suspect results and no positive results was usually negative after retesting. Herds having gilts with positive results were unlikely to have negative status after retesting.

Spread of pseudorabies virus among breeding swine in quarantined herds

In theory, pseudorabies virus (PRV) may be eliminated from any size of breeding herd by phased test and removal if replacement gilts are not infected with PRV, culling decisions are partially based on PRV status, and the cull rate is higher than the incidence rate of PRV. Annual cull rates are commonly at least 50%, but little information exists on the incidence of PRV within enzootically infected swine herds. The purpose of this study was to develop a method by which spread of PRV could be detected among breeding swine within enzootically infected herds and to determine the incidence of PRV infection in these herds. Data were collected from 17 herds that were quarantined for PRV and ranged in size from 120 to 1,100 sows. At each herd, within the first 5 days of introduction, a group of approximately 30 replacement gilts was identified, vaccinated with a glycoprotein X-deleted PRV vaccine, and blood sample was collected. The owner of 1 herd had a nonvaccinated breeding herd and elected to leave incoming gilts nonvaccinated. After vaccination, blood samples were collected every 1 to 2 months for an average of 13.6 months. Serum samples from vaccinated gilts were tested for antiglycoprotein X antibodies by a specific differential ELISA. Samples from nonvaccinated gilts were evaluated by serum neutralization test. Product-limit method was used to estimate the probability of not becoming infected with PRV. Spread was detected in 7 of 8 herds that had more than 400 sows and in 2 of 9 herds that had less than 400 sows.(ABSTRACT TRUNCATED AT 250 WORDS)

Factors associated with spread of pseudorabies virus among breeding swine in quarantined herds

Knowledge of the factors that place susceptible gilts at highest risk of pseudorabies virus (PRV) infection in a quarantined herd is crucial to reduce spread of PRV within the herd. Cohorts of PRV seronegative gilts were monitored in 17 herds that were endemically infected with PRV to determine the location of breeding females at the time of infection with PRV and identify herd characteristics and management and housing factors that may influence spread of PRV in the breeding section of swine herds endemically infected with PRV. Blood samples were collected every 1 to 2 months for an average of 13.6 months. In addition, blood was collected from a representative sample of finishing pigs (greater than or equal to 20 weeks old) 3 times per year to determine their serologic PRV status. Incidence rates and relative risks of PRV infection were estimated for 4 areas of the breeding section: gestation barn, gilt pool, farrowing room, and breeding area. Overall, 28, 11, 8, and 2 females became infected with PRV in each of these areas, respectively. The greater number of females infected in the gestation barns, compared with the number of females infected in other locations, is probably a consequence of being at risk for a longer period rather than of a higher incidence rate. Herd size, common housing for gilts in the gilt pool and sows, and serologic pattern of PRV infection in finishing pigs were associated with the detection of spread of PRV in the breeding section of the 17 herds.(ABSTRACT TRUNCATED AT 250 WORDS)

Differences in production values between high- and low-productivity swine breeding herds

Data were collected from 80 North American users of a computerized health and management software program for the period August 1985 through July 1986. Fifty-four herds were selected for analysis based on selection criteria of 1) stable herd inventory, 2) complete recorded data, 3) weaning-to-first service interval greater than 3 d and less than 20 d, and 4) culling rate greater than 10%. These herds had an average of 18.2 pigs weaned/(female.year) (PWFY), 2.1 litters/(female.year) (LFY), 81% farrowing rate, 10.2 pigs born live/litter and 14.5% preweaning mortality. Compared with the 14 herds with the lowest values for pigs weaned/(female.year), high-productivity herds (i.e., the 14 herds with the highest values for PWFY) had higher LFY, farrowing rate, total and live pigs born/litter and sow-gilt ratio; they also had lower nonproductive female days (NPFD), lower preweaning mortality and fewer gilts as a proportion of female inventory. Herd size and PWFY were not correlated. A negative correlation between herd size and pigs born live remained after controlling for average lactation length (r = -.30). Nonproductive female days was highly correlated with LFY (r = -.87). Increasing herd age, measured by the sow-gilt ratio, was associated mainly with a reduction in NPFD, although there was a slight positive association with pigs born alive (r = .29).