Circulating angiotensin-(1-7) is decreased in patients with isolated nocturnal hypertension

Isolated nocturnal hypertension (INHT), defined as nighttime elevated blood pressure (BP) with normal daytime BP assessed by ambulatory BP monitoring, is associated with higher cardiovascular morbidity and mortality. We hypothesized that an alteration in the circulating renin-angiotensin system (RAS) contributes to INHT development. We examined circulating levels of angiotensin (Ang) (1-7) and Ang II and ACE2 activity in 26 patients that met the INHT criteria, out of 50 that were referred for BP evaluation (62% women, 45 ± 16 years old). Those with INHT were older, had a higher BMI, lower circulating Ang-(1-7) (P = 0.002) and Ang II levels (P = 0.02) and no change in ACE2 activity compared to those normotensives. Nighttime DBP was significantly correlated with Ang-(1-7) and Ang II levels. Logistic regression showed significant association in Ang-(1-7) and Ang II levels with INHT. Our study reveals differences in circulating RAS in individuals with INHT.

[Prevalence, knowledge and control of arterial hypertension in vulnerable neighborhoods of Argentina: A Cross-sectional Study]

INTRODUCTION

Hypertension (HTN) represents the primary individual risk factor, contributing significantly to the global burden of cardiovascular diseases (CVD). In our country, epidemiological research has highlighted substantial variations in the prevalence of these risk factors across different populations. However, there is a lack of epidemiological studies assessing exclusive cardiovascular risk factors within vulnerable neighborhoods characterized by extremely limited economic resources, sociocultural challenges, and inadequate healthcare access.

METHODS

A multicenter cross-sectional observational study was conducted among individuals residing in economically deprived and marginalized communities, including informal settlements and underprivileged neighborhoods. Simple random sampling of households was employed. Blood pressure measurements, anthropometric assessments, and epidemiological, economic, and sociocultural questionnaires were administered. Results encompass prevalence rates, awareness levels, and blood pressure control across diverse regions. Logistic regression was utilized to identify independent variables influencing primary outcomes.

RESULTS

A total of 989 participants were analyzed. The overall prevalence of hypertension was 48.2%. About 82% had a body mass index (BMI) >25. Approximately 45.3% had less than 6 years of formal education. Independent association was established between education levels below 6 years and higher hypertension prevalence. Among hypertensive individuals, 44% were unaware of their condition, with only 17.2% achieving control, correlated with having health insurance and a higher educational background. Merely 24% were receiving combined therapy.

CONCLUSION

The prevalence of hypertension within vulnerable neighborhoods is alarmingly high, surpassing rates in other social strata. Knowledge, treatment, and control levels of hypertension are suboptimal, comparable to other populations. Inadequate use of combination therapy was observed. This study underscores the urgent need for targeted interventions addressing cardiovascular risk factors in poor areas to mitigate the burden of CVD.

Uncontrolled and masked uncontrolled blood pressure in treated pregnant women with chronic hypertension and risk for preeclampsia/eclampsia

To analyze the relationship between the level of BP achieved with treatment and the risk for development of preeclampsia/eclampsia (PE), we conducted a historical cohort study on 149 consecutive pregnant women with treated chronic hypertension, evaluated between January 1, 2016, and November 31, 2022. According to office BP readings and ambulatory blood pressure monitoring (ABPM) performed after 20 weeks of gestation, the cohort was classified in controlled hypertension, white-coat uncontrolled hypertension, masked uncontrolled hypertension and sustained hypertension. Risks for the development of PE were estimated using logistic regression. One hundred and twenty-four pregnant women with a control BP evaluation were included in this analysis. The rates of PE were 19.4%, 27.3%, 44.8% and 47.1% for controlled, white-coat uncontrolled, masked uncontrolled and sustained uncontrolled hypertension, respectively. Compared with women with controlled hypertension, the relative risk for PE increased markedly in women with sustained uncontrolled (OR 3.69, 95% CI, 1.19-11.45) and masked uncontrolled (OR 3.38, 95% CI, 1.30-11.45) hypertension, but not in those with white-coat uncontrolled (OR 1.56 95% CI, 0.36-6.70); adjustment for covariates did not modify the results. Each mmHg higher of systolic and diastolic daytime ABPM increased the relative risk for PE ~4% and ~5%, respectively. Each mmHg higher of systolic and diastolic nocturnal BP increased the risk ~5% and ~6%, respectively. When these risks were adjusted for ABPM values in opposite periods of the day, only nocturnal ABPM remained as a significant predictor. In conclusion, masked uncontrolled hypertension implies a substantial risk for the development of PE, comparable to those of sustained uncontrolled. The presence of nocturnal hypertension seems important.

Hypertension arising after 20 weeks of gestation: gestational hypertension or masked chronic hypertension?

The objectives of this study were 1-to evaluate the prevalence of masked chronic hypertension in pregnant women classified as gestational hypertension 2-to compare the risks of developing preeclampsia in true gestational hypertension vs those women classified as having gestational hypertension but who had had masked hypertension in the first half of pregnancy. We conducted a cohort study in consecutive high-risk pregnancies who were evaluated before 20 weeks of gestation. Women who developed gestational hypertension (normotension in the office before 20 weeks of gestation and office BP ≥ 140/90 mmHg and/or antihypertensive treatment in the second half of gestation) were divided, according to an ABPM performed before 20 weeks of pregnancy, in two subgroups: subgroup 1-if their ABPM was normal, and subgroup 2-if they had masked chronic hypertension. Risks for preeclampsia (PE) were estimated and compared with normotensive women. Before 20 weeks of gestation, 227 women were evaluated (age 32 ± 6 years, median gestation age 15 weeks); 67 had chronic hypertension (29.5%). Of the remaining 160, 39 developed gestational hypertension (16 in subgroup 1 and 23 insubgroup 2. Compared with normotensive pregnant women, subgroup 1 of women with gestational hypertension did not increase the risk of developing PE (OR = 0.76, 95% CI = 0.16-6.65). Conversely, subgroup 2 of gestational hypertension increased the risk of PE more than 4 times (0R = 4.47 CI = 1.16-12.63). Risk estimation did not change substantially after the adjustment for multiple possible confounders. In conclusion, the59% of women initially diagnosed as gestational hypertensive according to current recommendations had masked chronic hypertension and a very high risk of developing PE.

P01.14.B Visuospatial selective attention deficit after resection of right hemisphere gliomas: a multivariate lesion symptom mapping and diffusion tractography study

Background

The ability to select relevant information to current behavioural goals despite concomitant distractors (i.e. selective attention) is crucial for daily life. Despite the implication of fronto-parietal network in sustaining visuospatial selective attention has been considered crucial, the role of subcortical structures is still unclear. Aim of this study was to evaluate the impact of neurosurgical removal of right gliomas on visuospatial selective attention performances.

Material and Methods

The visuospatial selective attention domain was assessed pre- and postoperatively (1 month follow-up) in 73 patients operated for right hemisphere gliomas. Support-vector-regression lesion-symptom mapping and disconnectome analysis (Lesion Quantification Toolkit, HCP 1065 data) were used to evaluate the relationship between the resection cavities and the postoperative performance on a standardized selective attention test. To test and refine the atlas-based results, in a subset of 17 patients with preoperative diffusion tractography, the postoperative outcome was correlated with the percentage of disconnection for different white matter tracts.

Results

Results showed that resection of a cluster enclosing the SMA-complex and the surrounding white matter was significantly associated with a decline in visuospatial selective attention performances (p<.05). Disconnectome analysis at population level revealed that the deficit was significantly correlated with the resection of superior cortico-striatal fibres, superior thalamic radiations, corticopontine projections, callosal connections and fibres of the frontal aslant tract. Within all the cortico-subcortical terminations of these tracts, disconnection of streamlines of the SMA-complex was the most associated with selective attention deficits. Tractography in single patients confirmed the population level results and suggested that ventro-lateral resections in case of inferior frontal or insular tumours significantly disconnecting the frontal aslant tract but sparing superior projection fibres were not associated with any postoperative disturbances.

Conclusion

Results show converging evidence to support a critical role for the SMA/preSMA and its projections in maintaining efficiency of attentive control. The present results reveal the importance of a fronto-medial descending connectivity in mediating the voluntary control of visuospatial selective attention. From a surgical standpoint, to avoid postoperative deficits, it seems crucial to preserve SMA projection pathways, while the disconnection of the frontal aslant tract is feasible without any postoperative decline.

Bioimpedance measurements in dentistry to detect inflammation: numerical modelling and experimental results

Bioimpedance measurements represent an advantageous method to evaluate the physio-pathological conditions of biological tissues and their use is spreading in different application fields, from the evaluation of body composition to the vital signs monitoring, passing through the individuation of cancer tissues and the detection of different substances (e.g. glucose measurements in people affected by diabetes). In fact, tissues electric properties vary with their conditions; for example, electrical conductivity increases when there is an inflammatory process, because of the presence of oedema, hyperaemia and infiltration. Inflammatory phenomena are frequent in dentistry, in diseases like periodontitis and peri-implantitis; however, at present the diagnosis is mainly done with the naked eye, by observing the gingiva redness and swelling.

OBJECTIVE

The aim of this work is to prove the feasibility of the inflammation detection by means of bioimpedance measurements.

APPROACH

Both numerical simulations and preliminary experimental measurements provide significant outcomes in differentiating between healthy and inflamed tissues.

MAIN RESULTS

Percentage differences in the impedance modulus equal to 4-20% (numerical simulations) and 35-56% (experimental measurements), respectively, depending on the considered conditions (e.g. electrodes characteristics and inflammation severity), were found.

SIGNIFICANCE

Such a measure could be integrated in electromedical devices designed, for example, for the therapy of peri-implantitis, in order to personalise the therapeutic dose in terms of intensity and duration and focusing it on the impaired area, minimising the effects on the surrounding tissues.

An innovative therapy for peri-implantitis based on radio frequency electric current: numerical simulation results and clinical evidence

Peri-implantitis is a severe inflammatory pathology that affects soit and hard tissues surrounding dental implants. Nowadays, only prevention is effective to contrast peri-implantitis, but, in recent years, there is the clinical evidence of the efficiency of a therapy based on the application of radio frequency electric current, reporting that 81% of the cases (66 implants, 46 patients) were successfully treated. The aim of this paper is to present the therapy mechanism, exploring the distribution of the electric currents in normal and pathologic tissues. A 3D numerical FEM model of tooth root with a dental implant screwed in the alveolar bone has been realized and the therapy has been simulated in COMSOL Multiphysics® environment. Results show that the electric current is focused in the inflamed zone around the implant, due to the fact that its conductivity is higher than the healthy tissue one. Moreover, by means of a movable return electrode, the electric current and field lines can be guided in the most inflamed area, limiting the interference on healthy tissues and improving the therapy in the area of interest. In conclusion, it can be stated that this innovative therapy would make a personalized therapy for peri-implantitis possible, also through impedance measurements, allowing the clinician to evaluate the tissue inflammation state.

A numerical coefficient for evaluation of the environmental impact of electromagnetic fields radiated by base stations for mobile communications

The aim of this study is the development of an Electromagnetic Environmental Impact Factor (EEIF). This is a global parameter that represents the level of electromagnetic impact on a specific area due to the presence of radiating systems, such as base station (BS) antennas for mobile communications. The numerical value of the EEIF depends only on the electromagnetic field intensity, a well-defined physical quantity that can easily be measured or computed. The paper describes the significant parameters of the field distribution adopted to evaluate the EEIF, and the assumptions used to develop a proper scale of values. Finally, some examples of application of the EEIF method are analyzed for real situations in a typical urban area.

Macaque ventral premotor cortex exerts powerful facilitation of motor cortex outputs to upper limb motoneurons

The ventral premotor area (F5) is part of the cortical circuit controlling visuomotor grasp. F5 could influence hand motor function through at least two pathways: corticospinal projections and corticocortical projections to primary motor cortex (M1). We found that stimulation of macaque F5, which by itself evoked little or no detectable corticospinal output, could produce a robust modulation of motor outputs from M1. Arrays of fine microwires were implanted in F5 and M1. During terminal experiments under chloralose anesthesia, single stimuli delivered to M1 electrodes evoked direct (D) and indirect (I1,I2, and I3) corticospinal volleys. In contrast, single F5 shocks were ineffective; double shocks (3 msec separation) evoked small I waves but no D wave. However, when the test (T) M1 shock was conditioned (C) by single or double F5 shocks, there was strong facilitation of I2 and I3 waves from M1, with C-T intervals of <1 msec. Intracellular recordings from 79 arm and hand motoneurons (MNs) revealed no postsynaptic effects from single F5 shocks. In contrast, these stimuli produced a robust facilitation of I2 and I3 EPSPs evoked from M1 (60% of MNs); this was particularly marked in hand muscle MNs (92%). Muscimol injection in M1 reduced I waves from F5 and abolished the F5-induced facilitation of late I waves from M1, and of EPSPs associated with them. Thus, some motor effects evoked from F5 may be mediated by corticocortical inputs to M1 impinging on interneurons generating late corticospinal I waves. Similar mechanisms may allow F5 to modulate grasp-related outputs from M1.

Facilitation from ventral premotor cortex of primary motor cortex outputs to macaque hand muscles

We demonstrate that in the macaque monkey there is robust, short-latency facilitation by ventral premotor cortex (area F5) of motor outputs from primary motor cortex (M1) to contralateral intrinsic hand muscles. Experiments were carried out on two adult macaques under light sedation (ketamine plus medetomidine HCl). Facilitation of hand muscle electromyograms (EMG) was tested using arrays of fine intracortical microwires implanted, respectively, in the wrist/digit motor representations of F5 and M1, which were identified by previous mapping with intracortical microstimulation. Single pulses (70-200 microA) delivered to F5 microwires never evoked any EMG responses, but small responses were occasionally seen with double pulses (interval: 3 ms) at high intensity. However, both single- and double-pulse stimulation of F5 could facilitate the EMG responses evoked from M1 by single shocks. The facilitation was large (up to 4-fold with single and 12-fold with double F5 shocks) and occurred with an early onset, with significant effects at intervals of only 1-2 ms between conditioning F5 and test M1 stimuli. A number of possible pathways could be responsible for these effects, although it is argued that the most likely mechanism would be the facilitation, by cortico-cortical inputs from F5, of corticospinal I wave activity evoked from M1. This facilitatory action could be of considerable importance for the coupling of grasp-related neurons in F5 and M1 during visuomotor tasks.

Coordination of coupled hand and foot movements during childhood

To acquire further insight into the neural mechanisms governing the association of voluntary oscillations of ipsilateral hand and foot we investigated when and how coordination of such coupling develops in children 7-10 years old. Sixty-six children were asked to rhythmically oscillate their right hand and foot, paired in-phase or anti-phase (i.e. rotating in the same or in the opposite angular direction). Angular displacement was monitored by a potentiometric technique, and EMGs from extensor carpi radialis (ECR) and tibialis anterior (TA) were recorded. All subjects were able to couple in-phase oscillations, but 13 of them failed to perform the anti-phase task. Maximal frequency of oscillation was found to be positively correlated with age. Phase-relations between hand and foot oscillations and between onsets of the EMG activity in hand and foot movers were measured in 37 of the children. During in-phase coupling limb oscillations were kept in an almost perfect synchrony by three different modalities of muscle recruitment. Ten of the youngest children activated TA before ECR, while 13 of the oldest subjects activated ECR before TA, as do adults. The remaining 14 children (7-8 years old) activated the two muscles almost synchronously. During anti-phase coupling, most of the younger children (20) showed a strict phase-opposition between both EMG onsets and movements. The remaining 10 (9-10 years old) activated the ECR first. The hand frequency-response (i.e. the phase-relation between the onset of the EMG and the related movement) showed age-related changes, corresponding to the behaviour of a mass-spring model (with lumped parameters) decreasing its resonant frequency. Instead, the foot frequency-response remained unchanged. The age-related modifications of the hand frequency-response adequately explain the changes of the interlimb relations described above. These results show that central structures controlling hand and foot coupling are still immature before 10 years of age and reinforce the view that in-phase and anti-phase coupling require separate neural controls.

Motoneuronal pre-compensation for the low-pass filter characteristics of muscle. A quantitative appraisal in cat muscle units

1. The relevance of motoneurone dynamic sensitivity in compensating for the low-pass filter properties of muscle was assessed by stimulating cat muscle units (MUs) with impulse discharges generated by two current-to-rate converters: (i) a spinal motoneurone, sensitive to both the input intensity and its first derivative, and (ii) a linear current-to-rate converter, i.e. a neurone model with the same static sensitivity as the motoneurone but lacking dynamic sensitivity. 2. Discharges generated by injection of sine-wave currents in three motoneurones of the 'fast' type and in the three related model versions were applied to the axon of forty-six MUs. The MU isometric tension was modulated at the frequency of the current sine wave (0.5-20 Hz). Phase and gain of the current-to-force transduction were measured. 3. When MUs were driven by the model, the force lagged the current by 90 deg at 1 Hz in slow MUs and at around 5 Hz in fast MUs. Under motoneurone drive, the 90 deg phase lag was attained at frequencies about twice as high. 4. The gain of the transduction (peak-to-peak force modulation/peak-to-peak current modulation) decayed when the modulation frequency was increased. In all but five units, the cut-off frequency, Fco (gain attenuated by -3 dB), was higher when the unit was motoneurone driven (FcoCell) then when it was model driven (FcoMod). In both conditions, Fco was inversely correlated with the MU's time-to-peak. The advantage conferred by the motoneurone dynamic sensitivity was expressed by the Fco ratio (FcoCell/FcoMod). Across the MU population this ratio ranged from 0. 6-2.8, was inversely correlated with the time-to peak, and was directly correlated with the half-tension rate, i.e. the impulse rate at which MUs develop 50 % of their maximal tetanic force. The largest improvement (Fco ratio > 2.0) was found in units with mechanical features similar to those presumably coupled 'in vivo' to the motoneurones utilized for stimulation. 5. This estimate was confirmed in experiments in which trains of pulses, generated by injection of ramp currents in another motoneurone and the related model, were used to activate eight MUs, selected for being similar to that connected 'in vivo' to the motoneurone. As expected, for any given current slope the rising phase of isometric tension was steeper when units were motoneurone driven than when they were model driven. The gain (force slope/current slope) was plotted against the ramp slope to identify the cut-off slope, Sco, at which the gain was attenuated by -3 dB. In this homogeneous MU sample, the ratio expressing the advantage of the motoneurone drive (ScoCell/ScoMod, equivalent to the Fco ratio), ranged from 2.62-2.97, values comparable with those observed in sine-wave experiments when the motoneurone and muscle units were properly matched.

Normal high energy phosphate ratios in "stunned" human myocardium

OBJECTIVES

We sought to investigate whether alterations in cardiac high energy phosphates occur in postischemic "stunned" human myocardium.

BACKGROUND

Transient postischemic myocardial dysfunction is a common phenomenon that occurs in a variety of clinical settings in the absence of necrosis, and its pathogenesis is still unclear. Cardiac high energy phosphates are reduced during ischemia, and persistently altered myocardial high energy phosphate metabolism has been suggested as a mechanism contributing to stunning.

METHODS

We studied 29 patients with a first anterior myocardial infarction (MI) who underwent successful reperfusion within 6 h of the onset of chest pain. These patients underwent 31P magnetic resonance spectroscopy (MRS) a mean of 4 days after MI for measurement of left ventricular contractility and relative high energy phosphate metabolites. Twenty-one patients underwent a second 31P MRS study a mean of 39 days after MI. Eight volunteers served as control subjects.

RESULTS

Global and infarct area wall motion scores improved significantly between the early and late studies. No difference was found between early cardiac phosphocreatine (PCr)/beta-adenosine triphosphate (beta-ATP) ratios in patients and control subjects ([mean +/- SD] 1.51 +/- 0.17 vs. 1.61 +/- 0.18, respectively, p = 0.17) or between early and late study results in patients (1.51 +/- 0.17 vs. 1.53 +/- 0.17, respectively, p = 0.6). For alpha of 0.05, the study had a 90% power to detect a 9% difference.

CONCLUSIONS

The results of this study demonstrate normal myocardial PCr/ATP ratios in patients with myocardial stunning after reperfusion and suggest that relative cardiac high energy phosphates are not depleted in stunned human myocardium.

[Effects of partial ventriculectomy on left ventricular mechanical properties, shape, and geometry in patients with dilated cardiomyopathy]

PURPOSE

To investigate the short-term effects of the partial ventriculectomy (resection of lateral wall associated to mitral annuloplasty) on cardiac mechanics, contractility, shape and geometry of the left ventricle (LV).

METHODS

Eleven male patients with severe congestive heart failure due to dilated cardiomyopathy were studied. The mean age was 51 +/- 7 years and the functional class was III (five patients) or IV (six patients) before the surgery. Patients were evaluated before and at 17 +/- 4 days after the surgery by simultaneous LV pressure and echocardiographic data. End-diastolic pressure (EDP-mmHg), wall stress (EDS-g/cm2) and diameter (EDD-cm); endsystolic wall stress (ESS) and diameter (ESD), fractional shortening (FS-%) and maximal elastance (Emax-mmHg/ cm/s); the diastolic slope of the pressure-diameter (Kp-mmHg/cm) and stress-strain (Km-g/cm2) loops; shape (L/ EDD, adimensional, where L is the LV long axis) and geometry (Th/EDD, adimensional, where TH is the LV diastolic thickness) were obtained.

RESULTS

1) The ressected muscle fragments (diamond shape) were 10.8 +/- 1.3 cm in length and 5 +/- 0.6 cm in width; 2) all patients were discharged from hospital (15-29 days) in class I (eight cases), II (two), and III (one); 3) it was observed a decrease in EDP (24.3 +/- 7.7 x 17.5 +/- 3.2, p = 0.016); in EDD (8.0 +/- 0.7 x 7.2 +/- 0.8, p = 0.002); in EDS (57.9 +/- 26.8 x 37.4 +/- 19.2, p = 0.005); in ESS (199 +/- 46.9 x 102.8 +/- 33.1, p = 0.004); in ESD (7.1 +/- 0.7 x 5.7 +/- 0.8, p < 0.001); in Kp (22.3 +/- 15.9 x 11.5 +/- 6.9, p = 0.014); and in K(m) (467.4 +/- 212 x 214.6 +/- 87.4, p = 0.01); and, 4) it was noted an increase in FS (11.5 +/- 1.8 x 19.8 +/- 3.9, p < 0.001); in Emax (13.8 +/- 2.2 x 18.6 +/- 3.2, p < 0.001); and in L/EDD (1.32 +/- 0.1 x 1.47 +/- 0.13, p < 0.007) and Th/Dd (0.11 +/- 0.04 x 0.17 +/- 0.08, p < 0.038).

CONCLUSION

The partial ventriculectomy showed multiple significant beneficial effects in these dilated myopathic hearts.

[Acute effects of ibopamine on left ventricular mechanics and contractility in patients with idiopathic dilated cardiomyopathy]

PURPOSE

The effects of ibopamine (IBO) on left ventricular (LV) mechanics and contractility have not been described. The aim of this study was to test the hypothesis that IBO has a contractile effect at a dose of 200 mg.

METHODS

Ten male patients (43 +/- 7 years) with refractory heart failure due to idiopathic dilated cardiomyopathy were studied. The patients were submitted to simultaneous echo-Doppler and hemodynamic (microtip catheter) studies, before (B) and after (20, 40 and 60 minutes) a dose of 200 mg of IBO. LV pressure/diameter and stress/strain relations were obtained. Subsequently, heart rate (HR-bpm), cardiac output (CO-L/m), end-diastolic pressure (EDP-mmHg); fractional shortening (FS-%); maximal elastance (Emax-mmHg/cm/s); end systolic (ESS-g/cm2) and end-diastolic (EDS-g/cm2) stress; chamber (Kp-mmHg/cm) and muscle (K(m)-g/cm2) stiffness, and the time of constant relaxation (Tau-ms) were analyzed.

RESULTS

Results were presented as mean +/- standard deviation for conditions before and after IBO (20, 40 and 60 minutes) respectively. There was no change in HR (99 +/- 7; 100 +/- 7; 99 +/- 8; 99 +/- 10). Significant increases were observed in CO (4.13 +/- 1.28; 4.95 +/- 1.38; 5.13 +/- 1.86; 5.18 +/- 1.57), FS (13.7 +/- 2.4; 15.4 +/- 2.8; 15.9 +/- 1.8; 16.1 +/- 2.0), and Emax (14.8 +/- 3.2; 16 +/- 3.6; 17.7 +/- 4.2; 17.6 +/- 4.2). A transient (20 minutes) increase followed by a decrease (40 and 60 minutes) occurred in EDP (26.3 +/- 4.2; 30.6 +/- 6.4; 24.6 +/- 5.6; 22.3 +/- 4.6), EDS (79.7 +/- 22.8; 91.7 +/- 29.6; 79 +/- 31; 63 +/- 17.3), and Kp (27.2 +/- 12.6; 60 +/- 26.7; 27.9 +/- 11.7; 28.1 +/- 11).

CONCLUSION

IBO has a beneficial effect on LV systolic and diastolic function as well as on contractility in patients with heart failure due to idiopathic dilated cardiomyopathy.

[Effects of rejection on the contractile reserve of the graft after heart transplantation]

PURPOSE

To test the hypothesis that rejection could affect the contractility and contractile reserve of left ventricle after heart transplantation.

METHODS

Echocardiographic parameters and noninvasive blood pressure end-systolic pressure (ESP), heart rate (HR), end diastolic (EDV) and end-systolic (ESV) volumes, ejection fraction (EF), end-systolic stress (ESS) and the end-systolic relation (ESS/ESV) were recorded in 68 studies in 11 patients, seven days-12 months after heart transplantation. Accordingly with the endomyocardial biopsies results were divided into two groups: group A-with no rejection (53 studies), and group B-with rejection (15 studies).

RESULTS

The nitroprusside infusion changed significantly and in the same way, all the parameters except the ESS/ESV ratio (A = 5.5 +/- 1.7 x B = 4.8 +/- 1.5 g/cm2/mL, p = NS); there was a decrease in ESP (A = 107 +/- 15 and B = 109 +/- 12 mmHg, p = NS), EDV (A = 68 +/- 19 and B = 81 +/- 12 mL, p = NS), ESV (A = 12 +/- 5 and B = 18 +/- 12 mL, p = NS) and ESS (A = 59 +/- 13 and B = 82 +/- 20g/cm2, p = NS); there was an increase in HR (A = 94 +/- 9 and B = 93 +/- 16bpm, p = NS) and EF (A = 83 +/- 5 and B = 79 +/- 8%, p = NS). In the dobutamine study it was observed differences for both groups, except for ESP (A = 156 +/- 26 and B = 149 +/- 26mmHg, p = NS). The increase in HR, EF and ESS/ESV ratio was greater in group A (HR-A = 117 +/- 19 and B = 102 +/- 25bpm, p < 0.05; EF-A = 91 +/- 4 and B = 78 +/- 11%, p < 0.05; ESS/ESV-A = 13.1 +/- 6 and B = 6.1 +/- 3.1 g/cm2/mL, p < 0.05). For group A it was smaller the EDV (57 +/- 18 x 94 +/- 35 mL, p < 0.05), ESV (5 +/- 3 x 24 +/- 20 mL, p < 0.05) and ESS (57 +/- 21 x 102 +/- 40 g/cm2, p < 0.05).

CONCLUSION

Rejection may not induce changes in resting left ventricular contractility, however, the contractile reserve is depressed during an episode of moderate to severe rejection.

[Assessment of the myocardial functional reserve in patients with left ventricular aneurysm by radionuclide ventriculography. Response to isotonic exercise]

PURPOSE

To evaluate global and regional left ventricular (LV) ejection fractions (EF) by radionuclide ventriculography in patients with LV aneurysm at rest and during isotonic exercise.

METHODS

Twenty patients were studied by radionuclide ventriculography at rest and during exercise. All patients had been submitted to cineangiography and showed LV aneurysm post myocardial infarction.

RESULTS

Patients were divided according to LV EF in two groups: one with EF > or = 40% and the other with < 40% EF. Both groups showed normal response of global EF to exercise: mean rest EF was 40 +/- 14% and mean exercise EF was 45 +/- 14% (p < 0.01). When groups were considered separately, EF values showed the same behavior. Half of the patients showed normal response to exercise and the other half showed abnormal response. These changes were not associated with resting EF values, but were due to regional EF of lateral wall, that changed from 44 +/- 7 to 48 +/- 7% in the group of patients with normal LV EF response to stress and from 50 +/- 5 to 46 +/- 5% in those with abnormal response (p < 0.01).

CONCLUSION

The evaluation of regional ventricular EF by radionuclide ventriculography during exercise better discriminates functional reserve in patients with LV aneurysm than resting global EF. These findings could help the decision making of the therapeutic approach in this specific group of patients.

An accurate 3-D model for magnetic stimulation of the brain cortex

We present a 3-D model for the simulation of a realistic clinical situation during magnetic stimulation. The electromagnetic problem is solved by reconstructing the inhomogeneous head tissues from magnetic resonance images and associating relative values of conductivity to each tissue. Application of Maxwell's equations in the integral form leads to an equivalent 3-D electrical network, whose solution gives the current density distribution in the brain. The high spatial resolution and rigorous electromagnetic approach make this model an accurate and useful tool for stimulator design and for estimating the efficiency and safety of this clinical methodology.

[The repair of inguinal and/or crural hernias with giant Mersilene prostheses in the preperitoneal position]

The authors present 44 patients operated for hernias (inguinal and/or femoral) with a median pre-peritoneal approach positioning a mersilene mesh with Stoppa's technique. The results are very interesting considering that the hernias treated are all at high risk of recurrence. We had 4 complications (1 bleeding and 3 wound infections) that were conservatively treated, no mortality at all. The follow-up was of 12 months (mean) and no recurrence was discovered.

Computer modelling of brain cortex excitation by magnetic field pulses

In spite of many clinical and experimental applications, the technique of transcranial magnetic stimulation still presents obscure aspects. This especially concerns safety parameters and the exact characterization of the current induced by a single magnetic pulse. The model proposed consists of an equivalent electric network derived by Maxwell's equations and applied to discretized magnetic resonance imaging of a normal subject. This model allows accurate prediction of current distribution, charge per phase and dissipated energy.

[Magnetic resonance imaging in study of the temporo-mandibular joint. II. Pathologic findings]

A total of 107 temporomandibular joints (TMJ) were examined with two superconductive MR units at 1T and 1.5T. In 73 TMJs, MR revealed 55 disk displacements, 7 disk perforations, 10 joint space adhesions, 33 osteoarthrities, 3 avascular necroses of the mandibular condyle, and 25 joint effusions. These abnormalities are described and discussed. In spite of some limitations--e.g., motion artifacts and patients' claustrophobia--MR imaging is the procedure of choice in abnormal TMJs, because it yields useful information as to therapeutic choice (conservative versus surgical). Arthrography can be used as a complementary study technique in the patients with marked disagreement between clinical and MR findings. Arthroscopy should be used as a surgical procedure in abnormal TMJs selected by previous MR studies.

[Delayed consolidation and pseudarthrosis in posttraumatic pathology of the carpal scaphoid. A magnetic resonance study]

Delayed unions and fibrous or sclerotic non-unions of the carpal scaphoid are frequent sequelae of non-diagnosed or not properly treated fractures. The most important cause of abnormal unions is ischemic necrosis, due to the terminal vascularity of the carpal scaphoid. Conventional X-rays, scintigraphy, and CT do not yield sufficient information for a complete diagnosis; at present, MR imaging represents a valuable alternative, for it is a noninvasive technique able to provide a "biological imaging" of bone. Fourteen patients underwent surgical/nonsurgical treatment, based on the findings supplied by MR imaging. MR reliability was evaluated in relation to the therapeutic results obtained. The study proved MR imaging to provide important information as to therapy planning; in case of surgical treatment, MR imaging helped in choosing the most appropriate location for the insertion of bone graft or screw.

Absorbed power distributions from single or multiple waveguide applicators during microwave hyperthermia

A theoretical model has been developed to calculate the power distributions in biological-like tissues in direct contact with waveguide applicators. A numerical solution of the coupled integral equations is performed by means of their transformation into matrix equations by using the method of moments, where the biological tissue and the applicator are described by two independent matrices. The model permits an accurate evaluation of the electric field at the aperture. The application of this method for the evaluation of arrays is also discussed. Power contour plots produced by applicators routinely used in clinics have been computed and compared with experimental results obtained with tissue-equivalent phantoms for three typical bodies: homogeneous, stratified and inhomogeneous.