Association of endothelial lipase Thr111Ile polymorphism with lipid metabolism and microvascular complications in type 2 diabetic patients.

AIM: Endothelial lipase (EL) is a key enzyme in lipid metabolism, and a polymorphism in the EL gene may be a candidate for modulating lipid parameters in type 2 diabetic (T2D) patients. METHODS: In 396 T2D patients (age: 59.5 ± 10.7 years; BMI: 28.9 ± 5.3 kg/m(2); HbA(1c): 8.2 ± 1.9%), the c.584C>T polymorphism (rs2000813, p.Thr111Ile) was studied in 225 men (frequency of c.584T: 0.351) and 171 women (frequency of c.584T: 0.304). Patients' metabolic parameters, and macrovascular and microvascular complications, were assessed at baseline and at follow-up (mean: 4.2 years). RESULTS: Patients who were homozygous for the minor allele displayed modestly decreased low-density lipoprotein (LDL) cholesterol and raised apolipoprotein B at baseline, and raised systolic blood pressure and high-density lipoprotein (HDL) cholesterol on follow-up. Homozygosity for the minor allele was significantly associated with frequency of retinopathy (P=0.025), with TT homozygous patients more likely to have diabetic retinopathy (OR: 3.505; 95% CI: 1.491-8.239) both initially and at follow-up. CONCLUSION: The c.584C>T EL polymorphism is associated with a higher risk of diabetic retinopathy that could be linked to modifications in HDL-cholesterol metabolism and blood pressure levels.

Power motion imaging can improve image quality in stress conditions with tachycardia.

BACKGROUND: Stress echocardiographic studies are useful, but the evaluation of wall motion is sometimes suboptimal. The recently developed technique of power motion imaging can enhance mobile tissue definition. HYPOTHESIS: The study was undertaken to determine whether power motion imaging improves endocardial definition during tachycardia compared with conventional two-dimensional (2-D) imaging. METHODS: Twenty pigs were studied during pacing rates of 100, 120, and 150 beats/min. We compared power motion imaging with standard 2-D imaging using systolic thickening visualization (STV) scores (3 = excellent definition of systolic thickening approximately 0 = total lack of visualization of systolic thickening) at each heart rate. We calculated the sum of the scores of 22 left ventricular segments as the overall STV score, and also calculated the sum of the scores in 10 parasternal segments and 12 apical segments separately. RESULTS: The overall STV scores in both imaging methods were similar at 100 beats/min, but scores for power motion imaging were significantly higher than those of usual 2-D imaging at 120 and 150 beats/min. Using power motion imaging, the overall STV scores were similar as heart rate was increased; however, while using standard 2-D imaging, STV scores were significantly decreased as heart rate was increased. Findings were analyzed separately by parasternal and apical images. Especially in the parasternal images, the scores were significantly increased as heart rate was increased using power motion imaging. CONCLUSIONS: We conclude that power motion imaging improves the detection of endocardial border in stress condition with tachycardia, and thus this modality is useful for stress echocardiography.

A new approach to teleconferencing with intravascular US and cardiac angiography in a low-bandwidth environment.

A common problem in radiology teleconferencing is the difficulty of transmitting a large volume of data over communication channels with a relatively low bandwidth. Although videoconferencing systems are easily implemented, they generally require lossy image compression, which can lead to significantly altered findings. A teleconsultation and teleconferencing system was developed that uses a store-and-forward approach with high-quality dynamic medical images obtained with intravascular ultrasonography and cardiac angiography. The system allows use of high-resolution dynamic images while preserving their original quality and can be adapted to different clinical applications with varying requirements. The system involves a standard preparation procedure to transmit images from one location to another prior to a conference; once the conference starts, however, the system becomes fully automatic and synchronizes the display and manipulation of images in both locations without further image data transmission. In general radiologic applications, the system is superior to videoconferencing systems in that it does not require specialized hardware and dedicated high-bandwidth communication links. Further investigation with large-scale studies will be required to determine whether these benefits can lead to more widespread acceptance of such a system in routine clinical practice and whether teleconferencing itself can enhance the effectiveness of clinical procedures.

Teleconferencing with dynamic medical images.

Dynamic images, a sequence of static images displayed in rapid succession and perceived as a continuous motion by the human eye, are widely used in medicine. One of the primary objectives of telemedicine is the transmission of such images to a distant location to manage clinical problems remotely. A broad variety of methods is available to acquire, store, transmit, and display these images. However, the context of the clinical problem determines which of these methods can be deployed in a telemedicine solution. This paper discusses the advantages and disadvantages of the different technologies and presents an example of a teleconferencing system for interventional cardiology. This system acquires cardiac angiography and intravascular ultrasound images and transmits them over an existing Internet connection to a distant location. It is specifically optimized for clinical conferencing, where time is limited for each case presentation during the conference, compared to the relatively long time available for the conference preparation. The system takes advantage of this characteristic by transmitting the images well in advance of the clinical conference and displaying them synchronously in both locations during the conference. This allows for the preservation of the original image quality.

Coronary vasodilator effects of BNP: mechanisms of action in coronary conductance and resistance arteries.

Brain natriuretic peptide (BNP), a hormone secreted predominantly in ventricular myocytes, may influence coronary vascular tone. We studied the coronary vasodilatory response to BNP under physiological conditions and after preconstriction with endothelin-1 (ET-1) in anesthetized pigs. Average peak-flow velocity (APV) was measured using intracoronary Doppler, and cross-sectional area (CSA) was measured using intravascular ultrasound. Coronary blood flow (CBF) was calculated. Intracoronary BNP induced dose-dependent increases in CSA, APV, and CBF similar in magnitude to those induced by nitroglycerin (NTG). The magnitude of BNP-induced vasodilation was accentuated after preconstriction with ET-1. Pretreatment with either the nitric oxide synthase inhibitor Nomega-nitro-L-arginine methyl ester or the cyclooxygenase inhibitor indomethacin attenuated the coronary vasodilator effect of BNP in resistance arteries without influencing epicardial vasodilation. Pretreatment with the ATP-sensitive potassium-channel blocker glibenclamide enhanced epicardial vasodilation in response to BNP. We conclude that BNP exerts coronary vasodilator effects, predominantly in epicardial conductance vessels. An accentuated vasodilatory response to BNP occurs in ET-1-preconstricted arteries. BNP-induced vasodilation in coronary resistance arteries may be partially mediated via nitric oxide and/or prostaglandin release.

Frequency of ischemia during intracoronary ultrasound in women with and without coronary artery disease.

Myocardial ischemia is common during ICUS imaging in women with and without CAD. Although no long-term adverse effects occurred in our small sample, a larger sample of women is required to confirm our observations and to determine the precise mechanisms of ischemia. Such studies may determine whether the smaller diameter of coronary vessels in women makes the women more vulnerable than men to the occurrence of chest pain and ischemia during ICUS. Although ICUS is valuable in guiding coronary interventions, disposable catheters are costly. Studies are required to assess the cost-benefit ratio of incorporating ICUS with coronary interventional procedures. Until more is known, we recommend that nurses educate patients about ICUS, monitor them closely for ischemia and arrhythmias during the procedure, and consider obtaining 12-lead ECGs when patients undergo and ICUS procedure.

Physiological concentrations of estradiol attenuate endothelin 1-induced coronary vasoconstriction in vivo.

BACKGROUND: Estrogens are cardioprotective hormones and are reported to have antianginal properties. We examined the effect of physiological concentrations of 17beta-estradiol on coronary reactivity in anesthetized female farm pigs. METHODS AND RESULTS: Epicardial coronary cross-sectional area (CSA) was assessed by two-dimensional intravascular ultrasound, average coronary peak flow velocity (APV) by intravascular Doppler velocimetry, and coronary blood flow (CBF) was calculated. Dose-response curves to intracoronary endothelin-1 (ET-1, 1 pmol/L to 10 nmol/L), the selective ET(B) receptor agonist sarafotoxin (1 pmol/L to 10 nmol/L), and serotonin (0.1 nmol/L to 1 micromol/L) were assessed before and after a 10-minute infusion of intracoronary estradiol (1 nmol/L). Before estradiol administration, ET-1 induced significant dose-dependent decreases in CSA, APV, and CBF. Estradiol attenuated ET-1-induced epicardial vasoconstriction (P<.001) as well as ET-1-induced decreases in APV (P=.05) and CBF (P=.012). In an additional five pigs, vehicle (DMSO) had no effect on ET-1-induced coronary vasoconstriction. Before estradiol administration, sarafotoxin induced no net change in CSA but induced increases in APV and CBF, the extent of which did not change significantly after estradiol. Serotonin induced small decreases in CSA but increased APV and CBF. Estradiol did not influence serotonin-induced changes in CSA, APV, or CBF. CONCLUSIONS: We conclude that estradiol attenuates ET-1-induced vasoconstriction, possibly through effects on the ET(A) receptor, because selective ET(B) receptor-induced stimulation with sarafotoxin remained unchanged. Such an effect on the ET(A) receptor may relate to the antianginal properties of estrogens.

Use of intravascular ultrasound in evaluating repeated balloon rupture during coronary stenting.

Balloon rupture during coronary angioplasty is a well-recognized complication of PTCA. Coronary angiography commonly fails to elicit the cause of balloon perforation. We present a case with multiple balloon rupture during additional high-pressure inflations of a Palmaz-Schatz stent where intravascular ultrasound was useful in revealing a calcified lesion protruding through the struts of the stent.

Lifestyle modifications for hypertension. The many benefits are worth the effort.

Any approach to antihypertensive therapy should include lifestyle modifications. In the beginning, emphasis should be on weight loss and exercise, along with moderation of alcohol use and cessation of smoking. Patients should be encouraged to consume fresh rather than processed (and thus high-salt) foods and to limit use of salt in cooking and at the table. Even if patients eventually require antihypertensive medications, lifestyle modifications should continue, since there is evidence that such measures minimize the number and dose of medications required.

Decreased opsonization for Streptococcus pneumoniae in sickle cell disease: studies on selected complement components and immunoglobulins.

Opsonic activity for Streptococcus pneumoniae in the sera of patients with sickle cell disease was reduced in comparison to the opsonic activity of sera from age-matched normal children. No difference in opsonic activity for Escherichi coli was observed in the sera from patients or normals. Total hemolytic complement, conversion of C3 by inulin and cobra venom factor, and levels of C3, factor B, properdin, C3b inactivator, and immunoglobulins G, A, and M were normal in patients' sera. The opsonic abnormality for S. pneumoniae was attributed to a deficiency of serum proteins rather than to an inhibitor of opsonic function. The data suggest that decreased opsonization was not associated with a deficiency of those complement components or immunoglobulins measured in this study.