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.

Integrins, muscle agrin and sarcoglycans during muscular inactivity conditions: an immunohistochemical study

Sarcoglycans are transmembrane proteins that seem to be functionally and pathologically as important as dystrophin. Sarcoglycans cluster together to form a complex, which is localized in the cell membrane of skeletal, cardiac, and smooth muscle. It has been proposed that the dystrophin-glycoprotein complex (DGC) links the actin cytoskeleton with the extracellular matrix and the proper maintenance of this connection is thought to be crucial to the mechanical stability of the sarcolemma. The integrins are a family of heterodimeric cell surface receptors which play a crucial role in cell adhesion including cell-matrix and intracellular interactions and therefore are involved in various biological phenomena, including cell migration, and differentiation tissue repair. Sarcoglycans and integrins play a mechanical and signaling role stabilizing the systems during cycles of contraction and relaxation. Several studies suggested the possibility that integrins might play a role in muscle agrin signalling. On these basis, we performed an immunohistochemical analyzing sarcoglycans, integrins and agrin, on human skeletal muscle affected by sensitive-motor polyneuropathy, in order to better define the correlation between these proteins and neurogenic atrophy due to peripheral neuropathy. Our results showed the existence of a cascade mechanism which provoke a loss of regulatory effects of muscle activity on costameres, due to loss of muscle and neural agrin. This cascade mechanism could determine a quantitative modification of transmembrane receptors and loss of alpha7B could be replaced and reinforced by enhanced expression of the alpha7A integrin to restore muscle fiber viability. Second, it is possible that the reduced cycles of contraction and relaxation of muscle fibers, during muscular atrophy, provoke a loss of mechanical stresses transmitted over cell surface receptors that physically couple the cytoskeleton to extracellular matrix. Consequently, these mechanical changes could determine modifications of chemical signals through variations of pathway structural integrins, and alpha7A could replace alpha7B.

Ambulatory blood pressure monitoring and endothelium-dependent vasodilation in the elderly athletes

AIM

Regular exercise is a key component of cardiovascular risk prevention strategies, because it is associated with a variety of beneficial metabolic and vascular effects that reduce mortality and the incidence of cardiovascular adverse events. Endothelium plays an important role in the local regulation of vascular tone and structure, mainly by nitric oxide (NO) synthesis and action. Aim of the present study was to evaluate in elderly athletes the effect of regular aerobic exercise on arterial blood pressure (BP) and on endothelium-dependent flow-mediated dilation (FMD) of the brachial artery.

METHODS

The study population included 30 male subjects (mean age 65.6+/-5.6 years), who had practiced endurance running at a competitive level for at least 40 years, and 28 age- and sex-matched subjects (mean age 64.5+/-4.5 years) with sedentary lifestyle and free of cardiovascular disease. Athletes and control subjects underwent standard 12-lead ECG, clinic BP, 24-h ambulatory BP monitoring and endothelium-dependent FMD and endothelium-independent response to glyceryl trinitrate (GTN), 400 microg, in the brachial artery by high-resolution ultrasonography.

RESULTS

Systolic clinic and ambulatory 24-h BP were significantly lower in the athletes, than in the controls (P<0.001, respectively). Systolic and diastolic 24-h BP variability, when assessed either by the standard deviation (S.D.), or by the coefficient of variation (CV), were also significantly lower in the athletes (P<0.01). The athletes also had a lower 24-h, day-time and night-time heart rate (HR) (P<0.01), as well as a lower HR variability (P<0.01). As regards circadian BP change, the %Delta was statistically significant greater in athletes (P<0.05). Elderly athletes showed higher FMD than elderly sedentary subjects (P<0.001), whereas no differences were shown in the response to GTN.

CONCLUSIONS

Our results, suggest that long-term physical activity can counteract the age-related endothelial dysfunction that characterizes sedentary aging, preserving the capacity of the endothelium-dependent vasodilation and reduces BP values improving arterial pressure control.

An in vitro study on the free radical scavenging capacity of ergothioneine: comparison with reduced glutathione, uric acid and trolox

BACKGROUND

Treatment of oxidative stress-related pathologies is a possible therapeutical strategy for the future. Natural product with antioxidant properties could trigger this goal. The aim of this in vitro study was to assess the antioxidant activity of the natural product ergothioneine (EGT), a compound of plant origin, which is assimilated and conserved by mammals in erythrocytes, kidney, seminal fluid and liver.

METHODS

We measured the antioxidant activity of EGT as its ability to antagonize the oxidation of alpha-keto-gamma-methiolbutyric acid (KMBA) by hydroxyl radical, peroxyl radicals and peroxynitrite. The results are expressed as total oxyradical scavenging capacity (TOSC) units. Glutathione (GSH), uric acid and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox), the water-soluble analog of vitamin E, were used as the reference antioxidants.

RESULTS

EGT was the most active scavenger of free radicals as compared to classic antioxidants as GSH, uric acid and trolox. In particular, the highest antioxidant capacity exhibited by EGT vs. peroxyl radicals (5.53 +/- 1.27 units) resulted 25% higher than the value obtained with the reference antioxidant trolox (4.4 +/- 0.6 units, P < 0.01). The scavenging capacity of EGT towards hydroxyl radicals (0.34 +/- 0.09 units) was 60% higher, as compared to uric acid (0.21 +/- 0.04 units, P < 0.001), which represent the reference antioxidant vs. hydroxyl radicals. Finally, EGT showed the highest antioxidant activity also towards peroxynitrite (5.2 +/- 1.0 units), with a scavenging capacity 10% higher than that of uric acid (4.7 +/- 0.9 units, P < 0.05).

CONCLUSIONS

This study showed that EGT has potent intrinsic anti-hydroxyl, anti-peroxyl and anti-peroxynitrite radicals antioxidant activity, as compared to classic molecules with antioxidant capacity as GSH, trolox and uric acid. This appears of interest, given the increasing use of non-vitamins cocktails for therapeutical approaches to many oxidative-induced pathologies.

Effect of L-thyroxine treatment on left ventricular function in subclinical hypothyroidism

Aim of this study was to investigate the effects of thyroxine treatment on myocardial regional left ventricular (LV) systolic and diastolic function in patients with subclinical hypothyroidism (SH) by tissue Doppler imaging (TDI). Forty-two patients (29 women and 13 men; mean age 52.2+/-15.1 years) with SH, as judged by elevated serum thyroid-stimulating hormone (TSH) levels (>3.6 mIU/l; range, 3.8-12.0) and free thyroid hormones (FT4 and FT3) within the normal range, and 30 euthyroid volunteers (21 women and nine men; mean age 50.4+/-17.1 years) underwent standard echocardiography and TDI-derived early (Em) and late (Am) diastolic velocities, systolic (Sm) velocity, and isovolumetric relaxation time (IVRTm). Patients were randomly assigned to receive or not L-thyroxine replacement therapy. All patients returned after 6 months to repeat thyroid function tests and the evaluation of all parameters. No significant differences were seen in the Sm peak between SH and control groups. Respect to controls, SH patients exhibited a lower Em, a higher Am, and, subsequently, a reduced Em/Am ratio of both lateral wall (LW) and interventricular septum (IVS) (P<0.001 for both). The IVRTm was distinctly longer in SH patients, as compared to controls (P<0.001). At 6 months, L-thyroxine-treated patients showed a significant increase of Em (P<0.01) and a subsequent increase of the Em/Am ratio (P<0.01), whereas IVRTm significantly reduced (P<0.05). No significant change in any of these parameters was observed in the untreated group. Our data suggest that SH is associated with a subtle, reversible impairment of myocardial function. TDI analysis detects and extends these functional defects by displaying alterations in regional myocardial function. L-T4 replacement therapy should be advised for these patients with the aim to correct preclinical cardiac dysfunction and prevent the development of clinically significant myocardial dysfunction.

The investigation of skin blood flowmotion: a new approach to study the microcirculatory impairment in vascular diseases?

Skin blood flow oscillation, the so called flowmotion, is a consequence of the arteriolar diameter oscillations, i.e. vasomotion, and it is thought to play a critical role in favoring the optimal distribution of blood flow in the skin microvascular bed. Investigation of skin blood flowmotion, using spectral analysis of the skin laser Doppler flowmetry (LDF) signal, showed different flowmotion waves of endothelial, sympathetic or myogenic mediated vasomotion origin. Using this method in peripheral arterial obstructive disease (PAOD) patients an impairment of all the three flowmotion waves was found at level of the diseased leg following ischemia in the II stage of the disease and basally in critical limb ischemia. In patients with essential arterial hypertension (EHT) forearm skin blood flowmotion showed a post-ischemic impairment of myogenic and sympathetic components in newly diagnosed patients, and of endothelial and sympathetic components in long standing patients. In diabetic patients there was a selective impairment of skin flowmotion wave mediated by sympathetic activity in basal conditions. Investigation of skin blood flowmotion in response to different vasoactive substances demonstrated an important role of nitric oxide (NO) in controlling the endothelial component of vasomotion and an insulin action on smooth muscle cells of skin microvessels. All these data suggest that the study of skin blood flowmotion can become a method to early and easily detect skin microvascular impairment in vascular diseases and to investigate the mechanisms of substances active on skin microvascular bed.

Heart rate variability and QT dispersion in patients with subclinical hypothyroidism

The effect of subclinical hypothyroidism (SH) on cardiovascular autonomic function and ventricular repolarization has not been yet elucidated. The aim of the present study was to evaluate the dispersion of QT interval, i.e. an index of inhomogeneity of repolarization, and heart rate variability (HRV), i.e. a measure of cardiac autonomic modulation, in SH patients.

METHODS

The study included 42 patients (29 women and 13 men; mean age 53.2+/-14.2 years; body surface area 1.76+/-0.14 m2) with SH, as judged by elevated serum TSH levels (>3.6 mIU/l; range, 3.8-12.0) and normal free thyroid hormones (FT4 and FT3) and 30 euthyroid volunteer. Subjects with cardiac, metabolic, neurological disease or any other systemic disease that could affect autonomic activity were excluded from the study. Patients with SH and control subjects underwent a full history, physical examination, standard 12-lead ECG, and 24-h ambulatory ECG monitoring. To evaluate the effect of treatment with L-thyroxine on QT dispersion and HRV, 15 patients with SH were randomly assigned to receive therapy with L-thyroxine. All the subjects were evaluated at enrolment and after 6 months.

RESULTS

Patients with SH showed higher QT dispersion and lower HRV measures than healthy controls (P<0.01 for all). In SH patients, the standard deviation of N-Ns (SDNN) was negatively related to TSH (r=-0.42, P=0.006), while low frequency (LF)/high frequency (HF) ratio was positively related to TSH (r=0.42, P=0.006). Moreover, in SH patients both QT dispersion and QTc dispersion were positively related to TSH (r=0.64 and r=0.63, P<0.001 for both). After 6 months, the patients treated with L-tiroxine exhibited a reduction of QT dispersion and an increase of HRV parameters.

CONCLUSION

The results of the present study demonstrated that SH can alter autonomic modulation of heart rate and cause increased inhomogeneity of ventricular recovery times. Accordingly, early L-thyroxine treatment may be advised not only to prevent progression to overt hypothyroidism but also to improve abnormal cardiac autonomic function and ventricular repolarization inhomogeneity.

Endothelial function in young subjects with vaso-vagal syncope

BACKGROUND

The aim of this study was to determine whether endothelial function and inappropriate peripheral vasomotion have a significant role in the pathogenesis of neurally mediated syncope.

METHODS

In 16 patients (mean age 28.2+/-5.8 years) with previous vaso-vagal syncope and in matched healthy subjects, endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent response to glyceryl trinitrate (GTN), 25 mug, were measured in the brachial artery from high-resolution ultrasonography. Heart rate variability (HRV) analysis at rest and during tilt test was compared between two groups.

RESULTS

In the subjects with positive tilt test, all HRV parameters were significant higher respect to subjects with negative tilt test (P<0.001). The patients with positive tilt test, showed persistent, marked variability of heart rate (HR), due to increased vagal activity with withdrawal sympathetic tone and consequently reduction of blood pressure (BP) (-30.4+/-4.2 mmHg, P<0.001) accompanied by a decrease in HR (-24.3+/-4.5 beats/min, P<0.001) compared to negative tilt test subjects. These findings prove the real presence of vagal hypertone in patients with syncope. In our study, HR reached values lower than 40 beats/min. FMD in patients with neurally mediated syncope were significantly greater than those in controls (respectively, 9.2+/-2.8% vs. 4.6+/-1.4%, P<0.01) whereas no differences were shown in the response to GTN (18.4+/-4.4% vs. 16.1+/-4.2%, n.s.).

CONCLUSIONS

The augmented endothelial function and the abnormal vasodilation of peripheral arteries in association with bradycardia play an important role in the development of vaso-vagal syncope in young subjects.

Spectral Analysis of Skin Blood Flowmotion Before and After Exercise in Healthy Trained and in Sedentary Subjects

Cutaneous blood flowmotion (CBF) can contribute to a reduction in the resistance in skin microvascular networks. The increase of CBF during exercise can improve the capacity of skin microvascular networks to transport and eliminate heat. In order to verify if the physical training could increase the skin blood flowmotion during exercise, we performed spectral analysis of cutaneous forearm laser Doppler signal, before and after acute maximal exercise in 15 healthy trained subjects (TS) and in 15 control sedentary subjects (SS). Within the total spectrum of 0.009 - 2.3 Hz, five frequency intervals of CBF were analysed: 0.009 - 0.02 Hz (endothelial activity), 0.02 - 0.06 Hz (sympathetic activity), 0.06 - 0.2 Hz (vascular myogenic activity), 0.2 - 0.6 Hz (respiratory activity), and 0.6 - 2.3 Hz (heart activity). In basal conditions, no difference between TS and SS was observed in the cutaneous blood perfusion (CBP), expressed in conventional perfusion units (PU), and in the mean value of CBF total spectrum power density (PD), measured in PU/Hz, while the absolute PD of the endothelial and myogenic CBF components was significantly higher (p < 0.05) in TS (0.69 +/- 0.62 PU/Hz and 0.47 +/- 0.43 PU/Hz, respectively) than in SS (0.29 +/- 0.16 PU/Hz and 0.23 +/- 0.16 PU/Hz, respectively). In both TS and SS, acute exercise induced a significant increase of CBP mean value (30.91 +/- 20.28 PU, p < 0.0005 and 16.45 +/- 7.02 PU, p < 0.0005; respectively) and of CBF total spectrum PD (6.65 +/- 4.13 Hz/PU, p < 0.001 and 4.17 +/- 1.86 Hz/PU, p < 0.05; respectively), with a significant difference of these two parameters between the two groups (p < 0.05). After exercise, CBF components regarding endothelial and myogenic activities maintained a higher PD mean value in TS in respect to SS (1.69 +/- 1.34 PU/Hz and 1.59 +/- 0.93 versus 0.91 +/- 0.44 and 0.98 +/- 0.48 PU/Hz respectively, p < 0.05). These findings suggest that physical training is associated with the increase of CBF and particularly on its endothelial and myogenic components in response to exercise. This can favour a greater reduction of resistance in skin microvascular networks during exercise and consequently an increase of its capacity to transport and eliminate heat.

Right superior vena cava draining into the left atrium: prenatal diagnosis and postnatal management

Right superior vena cava (RSVC) draining into the left atrium, causing hypoxemia, represents a very rare congenital malformation which has not previously been described in the fetus. We describe a case in which fetal echocardiography at 22 weeks' gestation revealed an enlarged superior vena cava connecting abnormally with a mildly enlarged left atrium. Neonatal transthoracic echocardiography confirmed the diagnosis and showed an abnormal connection of the right pulmonary veins to the RSVC. Right-to-left shunt due to anomalous drainage of the RSVC into the left atrium associated with an atrial septal defect and anomalous pulmonary venous return were diagnosed on echocardiography and confirmed by angiography. The newborn was hemodynamically stable at birth and at the 1-year follow-up.

Malignant infantile osteopetrosis: dental effects in paediatric patients. Case reports

AIM

Malignant Infantile Osteopetrosis is a hereditary pathology caused due to osteoclastic cells which are incapable of carrying out their functions and hence do not resorb osseous tissue where required. Thus the consequence is that during growth phase, the medullary cavities and nervous tissue cavities do not undergo sufficient growth and the corresponding organs do not develop adequately. The aim of this study is to outline the role of the pediatric dentist who has to carry out protocols of primary, secondary, tertiary prevention intervening at many levels. Clinical features and dental effects are described. Two case reports are presented in this study.

CONCLUSION

Oral problems of osteopetrosis are delayed tooth eruption, absence of some teeth, malformed teeth, enamel hypoplasia, disturbed dentinogenesis, hypomineralisation of enamel and dentin, propensity for tooth decay, defects of the periodontal membrane, thickened lamina dura, mandibular protrusion, and the presence of odontomas. Tooth removal should be limited as it may induce bone fractures and osteomyelitis. The role of the pediatric dentist is defined.

Effect of chronic aerobic exercise on cutaneous microcirculatory flow response to insulin iontophoresis and to ischemia in elderly males

The aim of this study was to assess whether chronic aerobic exercise can favourably influence the vascular activity of insulin in elderly subjects. We measured in arbitrary units (A. U.) the cutaneous blood flow basally and in response to iontophoresis of insulin, by the means of a Laser Doppler flowmeter, on the right arm of 10 elderly athletes (10 males, aged 65 +/- 6 years) and of 10 sex- and age-matched sedentary subjects. The cutaneous blood flow response to ischemia was also explored in the right leg of the same subjects by means of the same instrument. No significant differences in cutaneous arm and leg blood flow were observed basally between athletes and sedentary subjects (7.25 +/- 2.65 A. U. versus 6.35 +/- 4.04 A. U. and 9.74 +/- 5.11 A. U. versus 9.41 +/- 6.40 A. U., respectively). Cathodal iontophoresis (six poulses of 0.1 mA each for 20 s, with 40-s interval between stimulations) of regular insulin (0.1 ml Humulin R 100 IU/ml diluted 1/10 with 0.9 % saline) induced a significant increase of cutaneous blood flow in both groups (p < 0.01 in athletes, p < 0.01 in sedentary subjects). However the maximal cutaneous blood flow response to insulin was higher in athletes than in sedentary subjects (24.69 +/- 13.34 A. U. versus 14.33 +/- 7.73 A. U., respectively, p < 0.05) as well as the curve of the net blood flux response to insulin iontophoresis (% change from baseline in response to insulin minus % change from baseline in response to saline iontophoresis) (p < 0.001 ANOVA for repeated measures). After ischemia there was a significant increase of leg cutaneous blood flow in both groups (p < 0.001 in athletes and in sedentary subjects) with higher blood flow response in athletes than in sedentary subjects (38.18 +/- 17.08 A. U. versus 26.01 +/- 6.39 A. U., respectively, p < 0.05). The time reached from the release of ischemia to peak-flow was significantly longer in sedentary subjects than in athletes (43.5 +/- 28.5 s versus 20.0 +/- 9.3 s, p < 0.05, respectively). These results suggest that chronic aerobic exercise increases insulin vasodilatory activity and improves endothelial function in elderly subjects.