Changes in autonomic regulation and ventricular repolarization induced by subclinical hyperthyroidism

The aim of the present study was to evaluate the effect of subclinical hyperthyroidism (SHT) on cardiovascular autonomic function and ventricular repolarization.

METHODS

Thirty subjects (25 females; mean age 49.6 ± 9.8 years) with SHT, as judged by reduced TSH serum levels and normal free T4 and T3 serum levels, and 30 age and sex-matched control subjects underwent standard 12-lead ECG, and 24h ambulatory ECG monitoring. The dispersion of the QT interval, an index of inhomogeneity of repolarization, and the heart rate variability (HRV), a measure of cardiac autonomic modulation, were studied.

RESULTS

Patients with SHT showed higher QT dispersion (p<0.001) and lower HRV measures (0.01>p<0.001) than controls. In SHT patients, QT dispersion was inversely related to HRV (r=-0.47, p<0.01).

CONCLUSION

The results of the present study demonstrated that SHT is associated with a sympathovagal imbalance, characterized by increased sympathetic activity in the presence of diminished vagal tone, and with an increased inhomogeneity of ventricular recovery times. The assessment of HRV and QT dispersion in patients with SHT may represent a useful tool in monitoring the cardiovascular risk of this condition.

Cardiac remodeling in patients with primary aldosteronism

OBJECTIVE

To evaluate the morpho-functional changes of the myocardium in patients with primary aldosteronism (PA).

DESIGN

An observational study in a university referral center for blood pressure diseases.

PATIENTS

Twenty- three patients with PA, 24 patients with essential hypertension (EH), and 15 normotensive controls (C) underwent conventional echocardiography with integrated backscatter (IBS) and tissue Doppler imaging (TDI) analysis. The corrected IBS (C-IBS) values and the systo-diastolic variation of IBS (CV-IBS) were performed at both interventricular septum and the posterior wall levels. TDI myocardial systolic (Sm), early diastolic (Em), and late diastolic (Am) velocities of both left ventricular walls were also determined.

RESULTS

In PA patients, septal and posterior wall CV-IBS were significantly lower than C (p<0.0001) and EH patients (p<0.001). In EH, CV-IBS was significantly lower than C (p<0.001). Patients with PA exhibited lower Sm, lower Em, and higher Am, and a subsequently reduced Em/Am ratio than C (p<0.001 for all) and EH (p<0.01 for all) at interventricular septum and lateral wall levels. In the latter, Sm, Em, and Em/Am ratio were lower and Am was higher than C (p<0.001 for all). In PA and EH patients, CV-IBS at both septum (r=-0.66, p<0.001) and posterior wall levels (r=-0.67, p<0.001) and Sm peak of both septum (r=-0.52, p<0.001) and lateral wall (r=-0.55, p<0.001) were inversely related to plasma aldosterone.

CONCLUSIONS

Patients with PA showed myocardial wall remodeling characterized by increased myocardial fibrosis and early left ventricular systodiastolic function abnormalities.

Prevalence of low back pain in former rhythmic gymnasts

AIM

It is still debated as to whether rhythmic gymnastics is a discipline at risk of low back pain, because the concern for the extreme and repetitive hyperextension of the column may be counteracted by protective factors which are distinctive of rhythmic gymnasts, namely: leanness, lumbar flexibility and muscle strength. This study aimed to assess the prevalence of low back pain in a cohort of former elite-level rhythmic gymnasts of the Rhythmic Gymnastics National Team.

METHODS

The Study Group included 60 adult females who were former rhythmic gymnasts of the Italian National Team. The Control Group included 60 adult females comparable for age, who were never involved in high level sport competitions. A standardized questionnaire was used to evaluate low back-pain symptoms.

RESULTS

Low back pain complaints were reported by 22 former rhythmic gymnasts and by 28 controls (36.6% vs. 46.6%, p: n.s.); in the ex-gymnasts the age of onset of pain was earlier than in controls. The former rhythmic gymnasts complaining low back pain reported a higher prevalence of symptoms also during the time of competitions, and retired earlier than those without pain.

CONCLUSIONS

Former elite rhythmic gymnasts reported a prevalence of low back-pain similar to sex and age matched general population. However, the rhythmic gymnasts who complained back pain during the sport activity are at risk of an early onset of symptoms after the retire from competitions. This study suggests that rhythmic gymnastics is not associated with increased risk of low back pain in the adult age.

Study of skin vasomotion during phollicular and luteal phase in young healthy women

The aim of this study was to evaluate if changes in female sex hormones associated to follicular phase (FP) and luteal phase (LP) may affect skin vasomotion in women with evidence of ovulatory cycle. Nine healthy non-smoker women aged 25+/-4 years, with regular menstrual cycle of 28+/-2 days and evidence of ovulation (indicated by a mid-luteal serum progesterone concentration > 5 ng/ml) (group-1) and six healthy non-smoker healthy women aged 24+/-2 years with evidence of an-ovulatory cycle (group-2) were enrolled in the study. At the times 1 (7th-10th day from the beginning of the last menstrual cycle) and at the time 2 (18th-22th day from the beginning of the last menstrual cycle) forearm skin vasomotion was investigated by means of spectral Fourier analysis of the skin laser Doppler flowmetry (LDF) tracing registered under basal conditions and following acetylcholine (ACh) iontophoresis. The power spectral density (PSD) of the 0.01-0.02, 0.02-0.06 and 0.06-0.2 Hz LDF tracing frequency intervals (related to endothelial-, sympathetic- and myogenic-dependent vasomotion, respectively) was measured in PU2 (LDF perfusion unit)/Hz (1 PU = 10 mV). At the same times skin blood flux response (percentage change from baseline) to ACh and to sodium nitroprusside (SNP) iontophoresis was also investigated. Basal and ACh-stimulated skin vasomotion did not significantly differ between time 1 and time 2 in PSD of the three frequency intervals investigated in both groups, as well as between the two groups at each time of investigation. Similarly, no significant changes were observed in skin vasodilator response to ACh and SNP iontophoresis between time 1 and 2 in each group. These results suggest that the female sex hormone changes associated to the FP and LP in young women with ovulatory cycle do not affect basal and ACh stimulated skin vasomotion as well as the endothelial- and non-endothelial-dependent skin vasoreactivity.

Theoretical investigation of the anticorrugation effects on the tribological properties of the Xe/Cu interface

We present a molecular dynamics study of the slip time and static friction for a slab of Xe deposited on a slab of Cu. To put in evidence the role played by the phonon field of the two blocks, we compare results obtained with a substrate formed by fixed atoms with one formed by mobile atoms. In the last case the scattering between Xe and Cu mobile atoms is inelastic and there is an exchange of momentum and energy between the two blocks which produces disorder in the interface plane. This disorder favors a decrease of the static friction and a consequent increase of the slip time. We describe the interaction between Xe and Cu with a phenomenological multi-ion potential which gives rise to an anticorrugation of the charge distribution and reproduces very well the ab initio density functional calculations. Our model potential is a linear superposition of a corrugating potential and an anticorrugating one. For this reason we can study the static friction by passing from an anticorrugated to a fully corrugated system. We also investigate the slip time and we compare our results with recent experimental data measured with the quartz crystal microbalance technique.

Varicocele and infertility: why a prevention?

The varicocele is the abnormal dilation of the veins of the pampiniform plexus, resulting from an altered venous drainage, and it is considered one of the main causes of male infertility. In this paper we review the most recent observations on the histological, endocrinological, biochemical and clinical alterations reported in adolescents with left idiopathic varicocele. Data indicate that varicocele progressively impairs the reproductive function of the testis. Treatment could improve a number of such damages.

Thermal effects in static friction: thermolubricity

We present a molecular dynamics analysis of the static friction between two thick slabs. The upper block is formed by N2 molecules and the lower block by Pb atoms. We study the effects of the temperature as well as the effects produced by the structure of the surface of the lower block on the static friction. To put in evidence the temperature effects we will compare the results obtained with the lower block formed by still atoms with those obtained when the atoms are allowed to vibrate (e.g., with phonons). To investigate the importance of the geometry of the surface of the lower block we apply the external force in different directions, with respect to a chosen crystallographic direction of the substrate. We show that the interaction between the lattice dynamics of the two blocks is responsible for the strong dependence of the static friction on the temperature. The lattice dynamics interaction between the two blocks strongly reduces the static friction, with respect to the case of the rigid substrate. This is due to the large momentum transfer between atoms and the N2 molecules which disorders the molecules of the interface layer. A further disorder is introduced by the temperature. We perform calculations at T = 20K which is a temperature below the melting, which for our slab is at 50K . We found that because of the disorder the static friction becomes independent of the direction of the external applied force. The very low value of the static friction seems to indicate that we are in a regime of thermolubricity similar to that observed in dynamical friction.

Stenting of the arterial duct in newborns with duct-dependent pulmonary circulation

OBJECTIVE

To evaluate the feasibility and results of stenting of the arterial duct in newborns with duct-dependent pulmonary circulation using low-profile, high-flexibility premounted coronary stents.

DESIGN

Prospective interventional and clinical follow-up study.

SETTING

Tertiary referral centre.

PATIENT POPULATION

Between April 2003 and December 2006, 26 neonates (mean (SD) age 15.2 (19.9) days, mean (SD) weight 3.3 (0.8) kg) underwent attempts at stenting of the arterial duct.

MAIN OUTCOME MEASURES

Procedural success and complication rates. Early and mid-term follow-up results.

RESULTS

The procedure was successfully completed in 24/26 (92.3%) cases. Minor complications occurred in 2/26 (7.7%) cases. No mortality occurred. After stenting, the ductal diameter increased from 1.2 (1.0) mm to 3.1 (0.4) mm (p<0.001) and the percutaneous O(2) saturation increased from 70 (14)% to 86 (10)% (p<0.001), respectively. Over a mid-term follow-up, 2/24 patients (8.3%) needed a systemic-to-pulmonary artery shunt because of inadequate ductal flow and 4/24 patients (16.7%) underwent stent redilatation after 6.0 (4.4) months, but before corrective surgery. Cardiac catheterisation before corrective surgery in 9 patients showed an increase of the Nakata index from 112 (49) mm/mm(2) to 226 (108) mm/mm(2) (p<0.001), without any left-to-right imbalance of the pulmonary artery size. In the subset of 11 patients who improved without needing an additional source of pulmonary blood supply, the stented arterial duct closed uneventfully in 45.5% of cases after 4.0 (2.2) months.

CONCLUSIONS

Stenting of the arterial duct is a feasible, safe and effective palliation in newborns with duct-dependent pulmonary circulation, supporting the spontaneous improvement process or promoting significant and balanced pulmonary artery growth for subsequent corrective surgery.

Skin blood flowmotion and microvascular reactivity investigation in hypercholesterolemic patients without clinically manifest arterial diseases

Fourier spectral analysis of forearm skin laser Doppler flowmetry (LDF) signal was performed in fifteen hypercholesterolemic patients (HP), without clinically manifest arterial diseases, and in fifteen age-matched healthy control subjects (CS), in order to investigate skin blood flowmotion (SBF). The LDF frequency intervals studied were: 0.01-1.6 Hz total spectrum, as well as 0.01-0.02 Hz (endothelial), 0.02-0.06 Hz (sympathetic), 0.06-0.2 Hz (myogenic), 0.2-0.6 Hz (respiratory) and 0.6-1.6 Hz (cardiac). Skin microvascular reactivity (MVR) to acetylcholine (ACh) and to sodium nitroprusside (SNP) iontophoresis was also investigated. HP showed a lower post-ACh increase in power spectral density (PSD) of the 0.01-0.02 Hz SBF subinterval compared to CS (1.80+/-1.73 PU(2)/Hz vs 3.59+/-1.78 PU(2)/Hz, respectively; p<0.005), while they did not differ in MVR from CS. In eleven HP the 0.01-0.02 Hz SBF subinterval showed a higher post-ACh PSD increase near to the statistical significance after 10 weeks of rosuvastatin therapy (10 mg/day) compared to pretreatment test (3.04+/-2.95 PU(2)/Hz vs 1.91+/-1.94 PU(2)/Hz; p=0.07). The blunted post-ACh increase in PSD of the 0.01-0.02 Hz SBF subinterval in HP suggests a skin endothelial dysfunction in these patients. This SBF abnormality showed a tendency to improve after rosuvastatin therapy in eleven treated patients.

Neonatal patent ductus arteriosus recanalization and stenting in critical Ebstein's anomaly

A critically ill 3-day-old neonate with severe tricuspid valve Ebstein's anomaly, functional pulmonary atresia, and closed ductus arteriosus, unresponsive to prostaglandin infusion, underwent percutaneous ductal recanalization and stenting as an alternative to a surgical shunt. After local prostaglandin infusion through an end-hole catheter, the ductus was passed using a hydrophilic, high-support coronary guidewire. It was then stabilized by coronary stent implantation, after which the arterial oxygen saturation showed a sudden rise. In conclusion, ductus arteriosus recanalization and stenting can be successfully achieved within a few days after spontaneous closure as a cost-effective alternative to a surgical shunt for critical neonatal, duct-dependent Ebstein's anomaly.

Post-ischaemic peak flow and myogenic flowmotion component are independent variables for skin post-ischaemic reactive hyperaemia in healthy subjects

The aim of this study was to clarify whether the post-ischaemic amplification of skin blood flowmotion (SBF) influences the extent of skin post-ischaemic hyperaemia. Forearm skin perfusion was measured by means of laser Doppler flowmetry (LDF) and forearm SBF was examined using Fourier analysis of LDF signal, under basal conditions and following forearm ischaemia in 50 healthy subjects. Power spectral density (PSD) of SBF total spectrum (0.009-1.6 Hz), as well of the frequency intervals (FI) related to endothelial (0.009-0.02 Hz), sympathetic (0.02-0.06 Hz), myogenic (0.06-0.2 Hz), respiratory (0.2-0.6 Hz) and cardiac (0.6-1.6 Hz) activity was measured in PU(2) (LDF perfusion unit)/Hz. Multiple regression analysis evaluated whether post-ischaemic peak-flow, as an indicator of shear stress, or post-ischaemic SBF independently affected the post-peak-flow hyperaemia calculated as corrected area under the LDF curve (C-AUC). Following ischaemia, we observed a statically significant increase in skin perfusion (from basal of 11.7+/-5.8 PU to peak flow of 62.3+/-41.4 PU, p<0.0000005) and in PSD of SBF total spectrum (p<0.01) as well of the different FI considered (p<0.005 for the endothelial and myogenic FI; p<0.05 for the sympathetic, respiratory and cardiac FI) compared to baseline. Multiple regression analysis showed that peak flow and post-ischaemic SBF component of myogenic origin were significant independent variables for the C-AUC (p=0.0000001 and p=0.009, respectively). These findings suggest that not only increased shear stress but also post-ischaemic amplification of myogenic SBF component independently contributes to the more prolonged phase of post-ischaemic skin re-perfusion in healthy subjects.

Skin microcirculatory effect of exogenous calcitonin gene-related peptide (CGRP) evaluated by laser Doppler flowmetry coupled with iontophoresis in healthy subjects

The aim of our study was to evaluate the feasibility of laser Doppler flowmetry (LDF) coupled with iontophoresis in exploring the skin vasodilator activity of exogenous calcitonin gene-related peptide (CGRP) in healthy subjects and to investigate the mechanisms involved in the skin vasodilator activity of this peptide. Forearm skin blood perfusion was measured in conventional perfusion unit (PU; 1 PU=10 mV), using a LDF apparatus (Periflux PF4001, Perimed, Sweden), before and following exogenous CGRP dissolved in distilled water (0.02%) or pure saline iontophoresis. Different iontophoresis protocols were used in a preliminary dose finding study in six subjects. Two pulses (0.1 mA for 30 s each) of anodal CGRP or saline iontophoresis were used in the definitive study in 20 subjects. Power spectral density (PSD) of skin blood flowmotion frequency intervals (FI), related to endothelial (0.009-0.02 Hz), sympathetic (0.02-0.06 Hz), myogenic (0.06-0.2 Hz), respiratory (0.2-0.6 Hz) and heart (0.6-1.6 Hz) activities, was also measured in PU(2)/Hz, by means of spectral analysis of the skin LDF signal registered before and following iontophoresis of CGRP or saline in the definitive study. A significantly higher per cent increase in skin perfusion compared to baseline was observed following CGRP than saline iontophoresis (548+/-369% vs. 326+/-192%, p<0.05), with higher hyperaemic response to pure saline than CGRP iontophoresis in only five subjects. A significant increase (p<0.05) in PSD mean value of the five FI considered, was also observed following CGRP iontophoresis, while saline iontophoresis elicited a significant increase (p<0.05) only in PSD of the FI related to endothelial, respiratory and heart activity. These findings demonstrated that LDF coupled with iontophoresis is a feasible method in evaluating the vasodilator effect of exogenous CGRP in human skin and suggest that this peptide directly or indirectly induces a smooth muscle vascular cells and sympathetic fibres stimulation.

Sarcoglycan immunoreactivity is lacking in infantile hypertrophic pyloric stenosis. A confocal laser scanning microscopic study

OBJECTIVES

The Dystrophin-Glycoprotein Complex (DGC) is a large multisubunit complex that plays a crucial role in maintaining the structural integrity and physiology of muscle fibers. Dystrophin has been reported to be absent in the pyloric muscle of infantile hypertrophic pyloric stenosis (IHPS) patients. The present study was designed to investigate the other two patterns of DGC (dystroglycan and sarcoglycan complexes) in normal pyloric muscle and their possible modifications in IHPS patients.

METHODS

Ten pyloric muscle biopsies were obtained from babies operated for IHPS and five control pylorus biopsy taken at autopsy from cases without gastrointestinal disease. The DGC sub-complexes (beta-dystroglican and beta, delta- sarcoglycans) were localized immunohistochemically using specific monoclonal antibodies. The results were evaluated using a confocal laser scanning microscope.

RESULTS

Positive immunolocalization of the two DGC sub complexes was demonstrated in the smooth muscle cells (SMCs) of the pyloric region of control patients. Similarly, a positive immune expression of beta-dystroglican was observed in the pyloric SMCs of IHPS patients. On the other hand a negative immunoreaction for sarcoglycans was recorded within the full thickness of the pyloric SMCs of these patients.

CONCLUSIONS

The absence of sarcoglycans within the hypertrophied pyloric muscle may be a predisposing factor in the pathogenesis of IHPS since it could alter the normal physiology of SMCs through the modifications of structural integrity of sarcolemma and signaling between the extracellular and intracellular compartment.

Absent post-ischemic increase of blood flowmotion in the cutaneous microcirculation of healthy chronic cigarette smokers

The aim of the study was to investigate whether chronic cigarette smoke habit is associated with changes of laser Doppler (LD) skin blood flowmotion (SBF). We performed spectral analysis of skin forearm LD signal detected by a LD flowmetry (Periflux PF4, Perimed, Sweden) before and during forearm post-ischemic hyperaemia, in 14 healthy chronic smoker subjects and 14 age and sex matched nonsmoker subjects. Forearm skin ischemia was obtained by a pneumatic cuff, positioned at the right arm and inflated for 3 minutes to 30 mmHg above systolic blood pressure. Power spectral density (PSD) of the SBF total spectrum (0.009-1.6 Hz), as well as 0.009-0.02 Hz , 0.02-0.06 Hz, 0.06-0.2 Hz, 0.2-0.6 Hz and 0.6-1.6 Hz frequency intervals (FI), referred to endothelial, sympathetic, myogenic, respiratory and heart activity, respectively, were measured in LD conventional perfusion units (PU)/Hz. Smokers showed a basal SBF total spectrum PSD mean values not significantly different from nonsmokers (2.14+/-1.58 PU/Hz and 1.93+/-1.35 PU/Hz, respectively). Following ischemia, PSD mean value of SBF total spectrum, as well of five FI considered, significantly increased in nonsmokers (p<0.01), while it did not significantly change in smokers. Smokers and nonsmokers did not differ in basal and post-ischemic skin LD perfusion mean values. The absent post-ischemic increase of the SBF and of its FI related to endothelial and myogenic activity in smokers can be an early sign of skin microcirculatory impairment, suggesting an endothelial and smooth muscle skin microvascular dysfunction associated with the chronic smoking habit.

[Cardiovascular remodelling in patients with sub-clinical hypothyroidism]

Sub-clinical hypothyroidism is defined by elevated serum thyroid-stimulating hormone level in the face of normal free thyroid hormone values. The role of sub-clinical hypothyroidism as independent risk factor for atherosclerosis has been suggested by clinical studies which demonstrated a higher prevalence of peripheral arterial disease, aortic atherosclerosis and coronary artery disease, in patients affected by this pathological condition. This association have been confirmed by the assessment of subclinical atherosclerosis by means of B-mode ultrasonography. Using this method an higher intima-media thickness (IMT) of carotid artery, a close marker of early atherosclerosis changes, have been found in patients with subclinical hypothyroidism compared to control euthyroid subjects. Levothyroxine replacement therapy of sub-clinical hypothyroidism was able to improve both the carotid IMT and atherogenic lipid profile, suggesting that lipid infiltration of the endothelium may represent a mechanism underlying the atherosclerotic process in patients with this pathological condition. Morphologic and functional changes of the myocardial tissue has been also demonstrated in patients with sub-clinical hypothyroidism, using ultrasonic backscatter video densitometry. All these data provide evidence of cardiovascular remodelling in patients with sub-clinical hypothyroidism. Vascular remodelling in sub-clinical hypothyroidism patients could be also studied by means of backscatter analysis of carotid artery, a method which allows the assessment of vascular sclerosis. Our preliminary results using this method suggested that not only atherosclerosis by also sclerosis characterises vascular remodelling in sub-clinical hypothyroidism patients.

Long term effects of bosentan treatment in adult patients with pulmonary arterial hypertension related to congenital heart disease (Eisenmenger physiology): safety, tolerability, clinical, and haemodynamic effect

BACKGROUND

Oral bosentan is an established treatment for pulmonary arterial hypertension (PAH).

OBJECTIVE

To evaluate safety, tolerability, and clinical and haemodynamic effects of bosentan in patients with PAH related to congenital heart disease (CHD).

PATIENTS

22 patients with CHD related PAH (8 men, 14 women, mean (SD) age 38 (10) years) were treated with oral bosentan (62.5 mg x 2/day for the first 4 weeks and then 125 mg x 2/day).

MAIN OUTCOME MEASURES

Clinical status, liver enzymes, World Health Organisation (WHO) functional class, resting oxygen saturations and 6-min walk test (6MWT) were assessed at baseline and at 1, 3, 6, and 12 months. Haemodynamic evaluation with cardiac catheterisation was performed at baseline and at 12 month follow-up.

RESULTS

12 patients had ventricular septal defect, 5 atrioventricular canal, 4 single ventricle, and 1 atrial septal defect. All patients tolerated bosentan well. No major side effects were seen. After a year of treatment, an improvement was seen in WHO functional class (2.5 (0.7) v 3.1 (0.7); p<0.05), oxygen saturation at rest (87 (6%) v 81 (9); p<0.001), heart rate at rest (81 (10) v 87 (14) bpm; p<0.05), distance travelled in the 6MWT (394 (73) v 320 (108) m; p<0.001), oxygen saturation at the end of the 6MWT (71 (14) v 63 (17%); p<0.05), Borg index (5.3 (1.8) v 6.5 (1.3); p<0.001), pulmonary vascular resistances index (14 (9) v 22 (12) WU m(2); p<0.001), systemic vascular resistances index (23 (11) v 27 (10) WU.m(2); p<0.01), pulmonary vascular resistances index/systemic vascular resistances index (0.6 (0.5) v 0.9 (0.6); p<0.05); pulmonary (4.0 (1.3) v 2.8 (0.9) l/min/m2; p<0.001) and systemic cardiac output (4.2 (1.4) v 3.4 (1.1) l/min/m2; p<0.05).

CONCLUSIONS

Bosentan was safe and well tolerated in adults with CHD related PAH during 12 months of treatment. Clinical status, exercise tolerance, and pulmonary haemodynamics improved considerably.