Layer-specific and whole wall global longitudinal strain predict major adverse cardiovascular events in patients with stable angina pectoris

The International Journal of Cardiovascular Imaging - Global longitudinal strain (GLS) has proven to be a powerful prognostic marker in various patient populations, but the prognostic value of...     

Epidemiology and natural history of hepatitis C virus infection among children and young people

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Treatment compliance in patients with aggressive periodontitis – a retrospective case-control study

Objective: To investigate if differences according to discontinuation of treatment could be identified between patients with aggressive periodontitis and chronic periodontitis at two specialist clinics of periodontology irrespective of the effects of background factors.

Materials and methods: This is a retrospective case-control study. The variables were registered from dental records. The population consisted of patients referred to two specialist clinics of periodontology during three years. A study group was included consisting of 234 patients with a diagnosis of aggressive periodontitis. A control group with a diagnosis of chronic periodontitis was randomly selected.

Results: In total, 234 patients (4% of the referrals) with a diagnosis of aggressive periodontitis were referred to the two periodontal clinics during a period of three years. Forty-two per cent of the non-compliant patients were smokers compared to 31% for the compliers and this difference was statistically significant. Patients with aggressive periodontitis interrupted their periodontal treatment significantly more frequently (46%) compared to those patients with chronic periodontitis (34%). The non-compliant patients had significantly deeper periodontal pockets at baseline as well as significantly more sites with bleeding at probing. In a stepwise logistic regression analysis, aggressive periodontitis, smoking and the relative frequency of sites with periodontal pockets >4?mm at baseline were the remaining variables with a significant influence on the incidence of interrupting ongoing periodontal treatment.

Conclusions: The patient group with aggressive periodontitis interrupted the periodontal treatment significantly more often irrespective of background factors and risk factors, which may be regarded as a major health problem.     

Nitrite‐derived nitric oxide: a possible mediator of ‘acidic–metabolic’ vasodilation

The fundamental, yet poorly understood, physiological mechanism known as ‘acidic–metabolic’ vasodilation, contributes to local blood flow regulation during hypoxia/ischaemia and increased metabolic activity. The vasodilator nitric oxide (NO) has been suggested to be involved in this event. Besides enzymatic production by NO synthases, a novel mechanism for generation of this gas in vivo was recently described. This involves non‐enzymatic reduction of inorganic nitrite to NO, a reaction that takes place predominantly during acidic/reducing conditions. We have studied the effects of physiological amounts of nitrite on NO generation and relaxation of rat aorta in vitro in a situation where environmental pH was reduced to levels seen in tissues during hypoxia/ischaemia. The relaxatory effect of nitrite was increased in an acidic buffer solution (pH 6.6) compared with neutral pH; EC50 for nitrite was reduced from 200 to 40 μM . Nitrite‐evoked relaxation was effectively prevented by coadministration of an inhibitor of soluble guanylyl cyclase. The relaxation was further potentiated by the addition of ascorbic acid. In parallel, NO was generated from nitrite in a pH dependent manner with even larger amounts seen after addition of ascorbic acid. NO generation from nitrite correlated to the the degree of relaxation of rat aorta. These results illustrate non‐enzymatic release of NO from nitrite at physiological concentrations. This may be an important auto‐regulated physiological mechanism involved in the regulation of vascular tone during hypoxia/ischaemia.     

Analysis of nitric oxide synthase genes in cluster headache

The aetiology of cluster headache is still not yet completely understood, but the potential relevance of genetic factors has been recognized during recent years. Nitric oxide (NO) plays a critical role in the regulation of vasodilation, neurotransmission, inflammation and many other events throughout the body. NO also appears to be an important mediator of vascular headache pathophysiology. In this study we have performed an association analysis of five polymorphic microsatellite markers in the three different NO synthase (NOS) genes; nNOS (NOS1), iNOS (NOS2A) and eNOS (NOS3). Ninety-one cluster headache patients diagnosed according to International Headache Society criteria and 111 matched controls were studied. Phenotype and allele frequencies were similarly distributed in patients and controls except for an iNOS (NOS2A) pentanucleotide repeat allele which was significantly more common in controls. We observed a higher phenotype frequency of this allele in our control group compared with rates in control groups of other studies, whereas the frequency in our patients was similar to that in controls from previous reports. Thus, we conclude that it is unlikely that genetic variations within the NOS genes contribute greatly to cluster headache susceptibility.     

Evaluation of aortic geometries created by magnetic resonance imaging data in healthy volunteers

Introduction: The development of atherosclerotic plaques has been associated with the patterns of wall shear stress (WSS). However, much is still uncertain with the methods used to calculate WSS. Correct vessel geometries are mandatory to get reliable estimations, and the purpose of this study was to evaluate an in vivo method for creating aortic 3D geometry in human based on data from magnetic resonance imaging (MRI) with ultrasound as reference. Methods: The aortas of ten healthy men, 23·4 ± 1·6 years of age, were examined with a 1·5 T MRI system using a 3D gadolinium‐enhanced gradient‐echo sequence. Three‐dimensional geometries were created using manual segmentation of images. Lumen diameters (LD) were measured in the abdominal aorta (AA) and the thoracic aorta (TA) with non‐invasive B‐mode ultrasound as a reference. Results: The anteroposterior diameter of the AA was 13·6 ± 1·1 mm for the MRI and 13·8 ± 1·3 mm for the ultrasound (NS). Intraobserver variability (CV) for MRI and ultrasound was <0·92% and <0·40%, respectively. Interobserver variability for MRI and ultrasound was 0·96% and 0·56%, respectively. The diameter of the TA was 19·2 ± 1·4 mm for the MRI, and the intraobserver variability (CV) was <0·78% and interobserver variability (CV) was 0·92%. Conclusion: Specific arterial geometries can be constructed with a high degree of accuracy using MRI. This indicates that the MRI geometries may be used to create realistic and correct geometries in the calculation of WSS in the aorta of human.     

A rapid method of theophylline assay in the physician's office

A competitive fluorescent enzyme immunoassay for theophylline is described which employs a theophylline monoclonal antibody. Fifty-two samples were assayed by this method and by high pressure liquid chromatography. The coefficient of correlation contrasting the methods equaled 0.979. The coefficient of determination was 0.959. The standard error of the correlation coefficient was 1.392. The bias of the immunoassay method versus high pressure liquid chromatography was 0.8 with 95% confidence limits of 0.4 to 1.2. In the same 52 patients, the precision of 1.6 with 95% confidence limits of 1.3 to 1.9 was obtained. There are numerous advantages of this new method compared with high pressure liquid chromatography. For the practicing physician, the rapid immunoassay for theophylline described here is proper for office application.     

Evidence for two neuropeptide Y receptors mediating vasoconstriction.

The presence of receptor subtypes mediating the vascular and prejunctional effects of neuropeptide Y (NPY) was investigated using the Y2 receptor agonist, NPY-(13-36), and the Y1 agonist, [Leu31,Pro34]NPY. NPY-(1-36) and [Leu31,Pro34]NPY administered i.v. to anesthetized pigs evoked dose-dependent increases in mean arterial blood pressure and splenic and renal vascular resistance, and a decrease in heart rate. The potency of [Leu31,Pro34]NPY was 10-30% that of NPY-(1-36). In the spleen, NPY-(13-36) evoked vasoconstriction similar to that evoked by [Leu31,Pro34]NPY, but did not significantly increase renal vascular resistance or mean arterial blood pressure. Local intra-arterial administration of [Leu31,Pro34]NPY caused an increase in nasal mucosal vascular resistance with a potency similar to that of NPY-(13-36) evoked only a minor (17%) increase in nasal mucosal vascular resistance. The NPY analogues were further characterized in receptor binding studies on pig spleen membranes. Compared to NPY-(1-36), 800 times higher concentrations of [Leu31,Pro34]NPY, and 7 times higher concentrations of NPY-(13-36) were required to achieve the same 50% displacement of [125I]NPY-(1-36). Electrically evoked contractions in rat vas deferens were inhibited by 50% by 0.05 microM NPY-(1-36) and 0.3 microM NPY-(13-36), while [Leu31,Pro34]NPY only slightly attenuated the contractions (by 24% at 1 microM). The present data suggest the existence of subtypes of NPY receptors mediating vasoconstriction. Thus, the splenic vascular bed of the pig contains both Y1 and Y2 receptors while the Y1 subtype predominates in the kidney, nasal mucosa and for blood pressure control. The prejunctional receptor in rat vas deferens seems to be of the Y2 subtype.