Atmospheric input of organic pollutants to the Venice Lagoon

The atmospheric deposition of dioxins and furans (PCDD-Fs), dioxin-like polychlorobyphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and hexachlorobenzene (HCB) was determined in the Lagoon of Venice. Sampling was carried out monthly, for a total of 13 months (July 1998-July 1999) using "bulk" samplers (passive collectors of wet and dry depositions) at four sites, inside the lagoon and close to its edge. Calculated PCDD-F loadings to the Lagoon turned out to be quite homogeneous, their range being approximately 10-20 ng m-2 y-1, whereas in the station located close to the industrial zone of Porto Marghera the value was approximately 50 ng m-2 y-1. PCB deposition in the industrial fallout sampling site and in the city centre of Venice was approximately 2500 ng m-2 y-1, that is, almost five times higher than the values measured at the northern and southern lagoon stations. HCB annual loading (approximately 8000 ng m-2 y-1) was almost six times higher in the industrial zone than in the other sites (approximately 1500 ng m-2 y-1). PAH loadings in the city centre of Venice and at Porto Marghera were 314 and 389 micrograms m-2 y-1, respectively. The amount of 2,3,7,8-TCDD equivalents (TEQ) of PCDD-Fs and PCBs in the Venice and Porto Marghera bulk depositions was compared with the guideline value of 15 pg m-2 d-1 for dioxins in depositions proposed by De Fré et al. (1998). Moreover, as some of the effects which drive the risk assessment of dioxin-like compounds were also observed after exposure to other molecules, the TEQs of PAHs and HCB were also calculated: nine out of 13 samples exceeded the guideline value. Lastly, an atmospheric emission source related to vinyl chloride monomer production, which may affect atmospheric deposition on the whole Lagoon, is reported in the industrial zone of Porto Marghera.

Mapping of early and late human somatosensory evoked brain potentials to phasic galvanic painful stimulation

In the present study, we modeled the spatiotemporal evolution of human somatosensory evoked cortical potentials (SEPs) to brief median-nerve galvanic painful stimulation. SEPs were recorded (-50 to +250 ms) from 12 healthy subjects following nonpainful (reference), slight painful, and moderate painful stimulations (subjective scale). Laplacian transformation of scalp SEPs reduced head volume conduction effects and annulled electric reference influence. Typical SEP components to the galvanic nonpainful stimulation were contralateral frontal P20-N30-N60-N120-P170, central P22-P40, and parietal N20-P30-P60-P120 (N = negativity, P = positivity, number = latency in ms). These components were observed also with the painful stimulations, the N60, N120, P170 having a longer latency with the painful than nonpainful stimulations. Additional SEP components elicited by the painful stimulations were parietomedian P80 as well as central N125, P170 (cP170), and P200. These additional SEP components included the typical vertex negative-positive complex following transient painful stimulations. Latency of the SEP components exclusively elicited by painful stimulation is highly compatible with the involvement of A delta myelinated fibers/spinothalamic pathway. The topography of these components is in line with the response of both nociceptive medial and lateral systems including bilateral primary sensorimotor and anterior cingulate cortical areas. The role of attentive, affective, and motor aspects in the modulation of the reported SEP components merits investigation in future experiments.

Gated blood pool tomography for the evaluation of global and regional left ventricular function in comparison to planar techniques and echocardiography

BACKGROUND

Multigated radionuclide ventriculography (MUGA) is a simple and reliable tool for the assessment of global systolic and diastolic function and in several studies it is still considered a standard for the assessment of left ventricular ejection fraction. However the evaluation of regional wall motion by MUGA is critical due to two-dimensional imaging and its clinical use is progressively declining in favor of echocardiography. Tomographic MUGA (T-MUGA) is not widely adopted in clinical practice. The aim of this study was to compare T-MUGA to planar MUGA (P-MUGA) for the assessment of global ejection fraction and to transthoracic echocardiography for the evaluation of regional wall motion.

METHODS

A 16-segment model was adopted for the comparison with echo regional wall motion. For each one of the 16 segments the normal range of T-MUGA ejection fraction was quantified and a normal data file was defined; the average value -2.5 SD was used as the lower threshold to identify abnormal segments. In addition, amplitude images from Fourier analysis were quantified and considered abnormal according to three different thresholds (25, 50 and 75% of the maximum).

RESULTS

In a study group of 33 consecutive patients the ejection fraction values of T-MUGA highly correlated with those of P-MUGA (r = 0.93). The regional ejection fraction (according to the normal database) and the amplitude analysis (50% threshold) allowed for the correct identification of 203/226 and 167/226 asynergic segments by echocardiography, and of 269/302 and 244/302 normal segments, respectively. Therefore sensitivity, specificity and overall accuracy to detect regional wall motion abnormalities were 90, 89, 89% and 74, 81, 79% for regional ejection fraction and amplitude analysis, respectively.

CONCLUSIONS

T-MUGA is a reliable tool for regional wall motion evaluation, well correlated with echocardiography, less subjective and able to provide quantitative data.

Recurrent proximal white subungual onychomycosis associated with a defect of the polymorphonuclear chemotaxis

Proximal white subungual onychomycosis (PWSO) is a rare form of nail infection that occurs almost exclusively in immunocompromised patients. Initially, in several reports, PWSO was described in ARC and AIDS patients. Later this pattern of onychomycosis was observed in patients with renal transplants, who received immunosuppressive therapy, and recently in a woman with active systemic lupus erythematosus (SLE) treated with systemic steroid therapy. We report a case of recurrent PWSO in a woman affected by a defect of polymorphonuclear chemotaxis. The association between PWSO and a defect of neutrophil chemotaxis, not yet described in the literature, suggests a point of discussion about the role of polymorphonuclear leucocyte functions in the defense mechanisms of the host affected by dermatophytosis. In this report the close association between PWSO and an immunocompromised condition is once again described. For this reason the authors emphasize the importance of investigating the common and uncommon causes of immunodeficiency in all patients affected by PWSO.

Clinical and laboratory manifestations of elderly onset psoriatic arthritis: a comparison with younger onset disease

OBJECTIVE

Although the influence of age on clinical and laboratory features has been widely demonstrated in many arthropathies, studies on elderly onset (> 60 years) psoriatic arthritis (EOPsA) are rare. This study compares manifestations at onset and two year outcome of EOPsA with those of younger onset PsA (YOPsA).

PATIENTS AND METHODS

Sixty-six consecutive PsA patients with disease duration < 1 year, 16 EOPsA (> 60 years) and 50 YOPsA (< or = 60 years) were admitted to a prospective study. Clinical, laboratory, and radiographic assessment were carried out at admission and after two years. HLA class I and bone scintigraphy were also recorded. In 10 patients with EOPsA and 24 with YOPsA it was possible to obtain synovial fluid, which was subsequently analysed for local inflammatory indices, including interleukin (IL) 1 beta, IL6, and IL8.

RESULTS

Presenting manifestations of EOPsA differed from YOPsA in number of active joints (mean (SD)) (12.2 (6.3) v 6.7 (4.6), p < 0.001), foot bone erosions (2.7 (1.2) v 1.1 (1.1), p < 0.001), erythrocyte sedimentation rate (64.2 (35.3) v 30.5 (30.0) mm 1st h, p < 0.001), C reactive protein (3.9 (2.0) v 1.3 (1.3) mg/dl, p < 0.001) and synovial fluid IL1 beta (8.0 (4.7) v 3.0 (3.0) pg/ml, p < 0.001) and IL6 (828.2 (492.6) v 469.3 (201.4) pg/ml, p < 0.005). No differences were found in the number of subjects with dactylitis, pitting oedema, HLA-B27, or signs of sacroiliac and sternoclavicular joint involvement at bone scintigraphy. After two years, progression was more evident in EOPsA than in YOPsA, as the number of new erosions in the hands and also the C reactive protein were higher in EOPsA patients.

CONCLUSION

PsA has a more severe onset and a more destructive outcome in elderly people (onset > 60 years) than in younger subjects. This behaviour may be influenced by immune changes associated with aging, as suggested by the higher concentrations of IL1 beta and IL6 found in the synovial fluid of EOPsA than in YOPsA.

Spectral analysis of intercycle heart fluctuations in the diethyl-ether-anaesthetized or pithed rat treated with prazosin, dl-propranolol, endothelin-1, alpha-r atriopeptin and ACE-inhibitors

1. Frequency-domain spectral analysis of stationary ECG R-R intervals was made by fast Fourier transformation (FFT) in conditions of monitored arterial blood pressure and respiratory activity in diethyl-ether-anaesthetized and pithed adult rats. This technique yields a number of parameters which allow quantitative evaluation of the non-random distribution of the mean values obtained in time-domain studies. The frequency-analysis method enables the overall heart rate variability to be broken down into its various constituents, which are differently affected by physiological loading and capable of selective reactivity to pharmacological agents. 2. The low-frequency spectral component obtained by breaking down the total spectral density power, i.e. the appropriate variability signal (band width < 0.15 Hz) and a higher-frequency band corresponding to spontaneous (0.80-1.60 Hz) or artificially imposed (0.75 Hz) respiratory activity were estimated and their integrated areas evaluated as absolute powers or normalized fractional values. 3. The power of the high-frequency spectral component increased in all animal preparations under treatment with prazosin, dl-propranolol, endothelin-1 and the angiotensin converting enzyme (ACE) inhibitors captopril, lisinopril, quinapril and ramipril. The power of the low-frequency band increased under alpha-r atriopeptin and ACE inhibitors in the pithed preparations only, and decreased in the anaesthetized animals. 4. The new power spectrum features and trends detected indicate that these time-independent, model-dependent cardiovascular and respiratory markers are subject to some form of complex peptidergic control. 5. The relative roles of the various factors operating in the genesis of these short-term changes in spectral power in the low- and high-frequency bands cannot be interpreted as indicating a reciprocal push-pull relationship between sympathetic and parasympathetic control. 6. The study findings, however, can be interpreted as providing evidence of a different and to some extent alternative form of integrative cardiovascular control persisting in the pithed rats (i.e. in the 'peripheral', CNS-destroyed preparations). 7. New areas of theoretical and applied research are being developed in the (auto)classification of (iso)receptors and drug analogues through exploration of multiple physiological and pharmacokinetic parameters in the frequency-domain. Furthermore, model-independent frequency-domain methods not requiring stationary data will afford scope for even more significant developments by separating the overlapping dynamic processes from a whole series of correlated effects.

Clinical, laboratory and immunogenetic aspects of post-traumatic psoriatic arthritis: a study of 25 patients

OBJECTIVE

In a previous study we demonstrated that the prevalence of trauma preceding arthritis was higher in patients with psoriatic arthritis (PsA) than in patients with rheumatoid arthritis (RA) or ankylosing spondylitis (AS); of 300 consecutive patients with PsA, 25 (8%) had a history of trauma before (< 3 months) the onset of the disease. The present study was carried out to characterize the clinical, laboratory and immunogenetic profiles of post-traumatic (PT)-PsA.

PATIENTS AND METHODS

The clinical and laboratory features of 25 patients with PT-PsA were studied at onset (first 6 months) and after a follow-up period of 1-7 years, and were compared with those of 275 PsA patients without any history of trauma (nonPT-PsA). HLA typing was performed in PT-PsA patients, and synovial fluid (SF) analysis, including interleukin (IL)-1 and IL-6 determinations, was carried out in 12 subjects with PT-PsA and in 32 with nonPT-PsA.

RESULTS

No differences were observed between PT-PsA and nonPT-PsA patients with regard to their clinical evolution. ESR (p < 0.0001) and CRP (p = 0.005) were higher in PT-PsA than in nonPT-PsA patients at disease onset but not after follow-up. No differences were found in the other blood indices. SF analysis revealed higher IL-6 levels in PT-PsA than in nonPT-PsA patients (p < 0.0005).

CONCLUSION

Our study demonstrates that the prevalence of trauma preceding arthritis is higher in PsA than in RA or AS. Clinical and laboratory findings in patients with PT-PsA differed from those with nonPT-PsA only at disease onset (first six months), however, showing an abrupt clinical presentation and a more acute phase response. This pattern may be related to the higher levels of IL-6 found in the SF of PT-PsA than in nonPT-PsA patients. However, during the follow-up period the two groups became indistinguishable, and no difference was observed between PT-PsA and nonPT-PsA regarding the evolution of the disease.

Teaching sign language to hearing children as a possible factor in cognitive enhancement

We describe an educational experience designed to teach Italian Sign Language (LIS) to a group of hearing children. The hypothesis underlying this experience was that learning a visual-gestural language such as LIS may improve children's attentional abilities, visual discrimination, and spatial memory. To examine this hypothesis, we conducted two studies. The first involved an educational experience lasting two years with a group of hearing children attending a Sign Language class from first to second grade. The Raven PM 47 TEST was administered at the beginning and at the end of each school year to children attending the LIS classes and to a control group of children enrolled in the same school but not exposed to LIS. The second study involved an educational experience in first grade. The Raven PM 47 and Corsi's block tapping tests were administered at the beginning and at the end of the school year to the children attending the LIS classes, to children enrolled in the same school but at tending an English class, and to children not exposed to a second language. We found that in both studies the LIS group performed better than the other groups. These results suggest that learning a sign language may lead to a cognitive advancement in hearing children.

(ECTO) nucleotidase kinetics observed by 31P-NMR spectroscopy: resolution of signals

We used 31P-NMR to study the action of the drug ouabain, a digitalis glycoside, on the ecto-nucleotidase catalysed reaction pathway: [formula: see text] Even under conditions where it was impossible to resolve all resonances from the individual species, the rate constants for the individual steps may be evaluated by a chi 2 fit of equations describing the global kinetics to the NMR data. The fitted values of the reaction rate constants show no inhibition of any step in the reaction pathway, confirming previous results. This improved kinetic method can be used to evaluate the effect of different substrates, ions and drugs, both in intact or pathologically altered organs and in tissue subcellular fractions.

Spectral analysis of intercycle heart fluctuations in Xenopus laevis, conscious or spinalized, treated with calcium channel blockers. Part I

1. In this study, electrocardiographic second lead tracings were recorded and analyzed online and offline in the conscious and spinalized Xenopus laevis under control conditions and after treatment with at least two effective doses of racemic diltiazem, nifedipine and racemic verapamil hydrochlorides. 2. Heart rates (HR) and intercycle heart rate power spectra (IHRPS) were calculated in the various experimental conditions. 3. Dose-dependent bradycardia was found in most cases, which was associated with dose-related increases in the overall dynamic range of the largest peak of HR variability (increased IHRPS), this being particularly marked at the higher nifedipine dose. The frequency position of the largest peak was unchanged in the spinalized preparation, as well as in the various treatments. 4. These findings may contribute toward a more complete pharmacodynamic definition of calcium channel blockers in their current therapeutic use.

Spectral analysis of intercycle heart fluctuations in the diethyl-ether-anaesthetized or pithed rat treated with l-hyoscyamine

1. Within the context of neural regulation of the activity of sinus node pacemaker cells, the study of heart rate variability, as explored in the frequency domain by spectral analysis, was proposed about 15 years ago as a quantitative tool for the evaluation of short-term autonomic cardiovascular control. It has since been postulated that the two main oscillations observed, one at low and the other at high frequency, may respectively be markers of sympathetic vs. vagal efferent cardiac activity, and that the low- and high-frequency signals may reflect a reciprocal or 'push-pull' relationship between sympathetic and parasympathetic control. 2. In our power spectra assessment, ECG R-R intervals were submitted to fast Fourier transformation analysis in order to study the mechanisms underlying the control of heart beats in rats. Data were acquired in conditions of steady arterial blood pressure and cardiac and respiratory activity (spontaneous or artificially stimulated) in diethyl-ether-anaesthetized and pithed rats, as well as in a group of control rats, all in the presence and absence of l-hyoscyamine. 3. With increasing doses of the parasympathetic antagonist, the fractal dimension of the time-series structure remained stable in most cases. The low-frequency spectral component narrowed with increasing drug doses and the high-frequency band underwent either no, or only very slight, changes. 4. In these rodent assays, the low- and high-frequency signals cannot be interpreted as a push-pull relationship between sympathetic and parasympathetic control.

Value of synovial fluid interleukin-1 beta determination in predicting the outcome of psoriatic monoarthritis

OBJECTIVE

To investigate the value of synovial fluid analysis in predicting the outcome of psoriatic monoarthritis.

METHODS

In synovial fluid from knee joints of 18 patients with psoriatic monoarthritis lasting less than six months, white blood cell count, acid phosphatase, lysozyme, and interleukin (IL)-1 beta were determined. ESR and serum C reactive protein were also measured. To define the outcome, the patients were monitored for at least three years and then subdivided into those with polyarthritis and those without.

RESULTS

Among the blood and synovial fluid indices considered, synovial fluid IL-1 beta was the only variable which differed between the patients who developed polyarthritis, within three years and those without polyarthritis after this time, at 20.82(SD 8.79) v 4.19(4.73) pg ml-1, P < 0.0001). A correlation was found between synovial fluid IL-1 beta concentrations and the number of affected joints after three years (r = 0.739, P < 0.0001).

CONCLUSIONS

Determination of synovial fluid IL-1 beta at disease onset may be useful in revealing the outcome of psoriatic monoarthritis since, among the variables considered in our study, this was the only one capable of predicting the evolution of monoarticular psoriatic arthritis to polyarthritis.

Synovial fluid levels of proinflammatory interleukins and their inter-relationships in elderly vs younger onset rheumatoid arthritis

Elderly-onset rheumatoid arthritis (EORA) is thought to be different from younger-onset disease (YORA) for many reasons, including a more elevated acute phase response and a more abrupt onset; both events are mainly regulated by pro-inflammatory interleukins (ILs), in particular, IL-1, IL-6 and IL-8. To compare the synovial fluid (SF) levels of these ILs, and their relationship to local inflammation as well as the acute phase response, erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP) in the two RA subsets, we determined white blood cell (WBC) number, total protein (TP), IL-1beta, IL-6 and IL-8 concentrations in the SF of 50 patients, 15 with EORA and 35 with YORA. Both ESR and CRP were higher in EORA than in YORA. IL-6 was higher in SF of EORA (2111.37 +/- 1425.03 pg/mL) than YORA (1077.53 +/- 757.62 pg/mL, p = 0.002), while no difference was observed for SF IL-1beta and IL-8. There was a weak correlation between SF IL-6 and IL-1beta in EORA, whereas SF ILs and CRP and/or ESR did not show any correlation in both groups. Our study indicates that in EORA, as in other diseases occurring in the elderly, there are elevated levels of IL-6. Higher SF levels of IL-6 may be, at least in part, responsible for the different behavior of EORA with respect to YORA.

Neuromagnetic localization of the late component of the contingent negative variation

The contingent negative variation (CNV) in a warned choice reaction time task was studied in 24 healthy subjects by use of magnetoencephalography (MEG). Special interest was focused on the late component of the CNV, CNVL. Source localization of the magnetically recorded CNVL, mCNVL was performed on 13 subjects, selected on the basis of the strength and stationarity of the electrically recorded CNV, eCNVL. To achieve whole head mapping, up to 500 epochs from different scalp positions were recorded, including a pretrial learning period of 40 epochs. The neuromagnetic signals studied in this experimental protocol are thus related to neurological processes that are present after an initial learning period has occurred. In 11 subjects, a goodness of fit between 88% and 95% was achieved using a two-dipole model with one equivalent source localized close to the precentral cortex contralateral to the side of movement, at mean a depth of 30 mm. Estimates of ipsilateral equivalent sources were less consistent across subjects. In 9 subjects the estimated ipsilateral sources were located symmetrically to the contralateral source. The results of this study suggest that the dominant source of the mCNVL is located near the bottom of the sulcus precentralis at the anterior bank of the gyrus precentralis, close to the sulcus frontalis superior. This supports previous findings that the CNVL is closely related to the readiness potential, and that the major cortical activity is symmetrically located in the left and right premotor areas.

Evaluation of technetium-99m-sestamibi lung uptake: correlation with left ventricular function

Lung uptake of 201Tl is a reliable marker of left ventricular dysfunction. The goal of our study was to establish whether the evaluation of lung-to-heart uptake ratios (LHR) with 99mTc-sestamibi imaging may provide valuable information.

METHODS

We studied 72 male subjects with recent anterior myocardial infarction undergoing 99mTc-sestamibi first-pass ventriculography and SPECT perfusion imaging. A group of 46 gender-matched subjects with low pre-test likelihood of CAD and normal exercise and rest 99mTc-sestamibi perfusion images was used as a control. The lung-to-heart count ratios (LHR) were calculated on planar projections from the sets of SPECT images.

RESULTS

Both groups were studied at rest and after a symptom-limited exercise tolerance test. In the control group a significant decrease in LHR was observed during stress (p < 0.001). The infarcted group showed significantly higher LHR values both at rest and at stress. Exercise and rest LHR values did not differ significantly. A positive correlation was observed between LHR values and left ventricular ejection fraction at rest and stress.

CONCLUSION

LHR, measured by 99mTc-sestamibi imaging, gives clinically useful information. Both resting and postexercise values are correlated with ejection fraction and should predict left ventricular dysfunction.

Some approaches to the pharmacology of multisubstrate enzyme systems

Analytical and exploratory in vitro, in situ and in vivo, physio-pharmacotoxicology, from enzymology to population epidemiology, now embraces those approaches that correlate complex dynamic multisubstrate kinetics through conventional and more recent non-invasive quantitative methodologies. Basically, substrates may be classed as pertaining to fundamental energy turnovers (first-order cellular metabolic pathways or networks) and to iso- vs allosteric modulator systems (second-order metabolic control network). Pairs of substrates and cofactors set-up the third-order multienzyme-receptor patterns, which in intact, native in vivo structures establish and maintain the compartmentalized, dynamically superimposed overall coordination of local redox and phosphate potentials. Perturbations of the various levels of the metabolic hierarchy induced by drugs, as well their relaxations, can be readily submitted to non-invasive kinetic analysis. Both indirect and direct titrations of substrate levels, their modelling and statistical ad hoc evaluations of their interrelations can lead to the identification of the multiple sites involved in drug effects as structured at the different orders/levels of concomitant functional variations. Fractal geometries contribute towards defining the space- and time-related events.

A 31P NMR spectroscopy study of Xenopus laevis heart perfused in vitro with creatinol-O-phosphate, phosphocreatine, adenosine triphosphate, fructose diphosphate and ouabain

Xenopus laevis heart was studied by 31P NMR using a 200 MHz proton spectrometer; hearts were perfused, at pH 7.35 and room temperature, with normal oxygenated or K(+)-enriched Ringer. Solution was later added with creatinol-O-phosphate (COP), phosphocreatine (PCr), adenosine triphosphate (ATP), fructose-1,6-diphosphate (FDP) and ouabain. NMR spectra of the heart show organic phosphomono- and phosphodi-esters, inorganic phosphate, PCr, overlapping alpha-ATP/ADP and gamma-ATP/beta-ADP, and beta-ATP signals. Their chemical shift positions and areas showed no significant changes in the course of 1.5 h perfusions with either solution, except in a few preparations, whether the heart was beating or reversibly arrested. While COP reduced the signals in beating hearts, the same spectra exhibited no consistent, substantial changes under PCr, ATP and FDP 1 to 10 mM, pH 7.35 perfusion with either solution, nor when ouabain mumol was added. The spectra are briefly discussed in comparison with those observed in the perfused heart of mammals (mostly rat), and particularly with those obtained in the frog (Rana temporaria) heart, both by analysing the bioenergetic equilibria on the basis of total tissue substrate levels measured in extracts of freeze-clamped tissue, and by evaluating cytochrome-b, flavin and pyridine nucleotide in vitro oxido-reduction read-outs in separate, similar experimental settings.

Continuous read-out of cytochrome b, flavin and pyridine nucleotide oxido-reduction processes in the perfused frog heart and contracting skeletal muscle

The time-sharing instrument for continuous read-out of the fluorescence levels of NAD(P)H and oxidized-flavoproteins, which also makes simultaneous dual beam differential absorption measurements of cytochrome b, has been applied to the study of the metabolic control of the frog heart, perfused in vitro with normal and variously modified Ringer solutions, and to the frog skeletal muscle in situ. In the ionically depolarized resting heart, the long term kinetic analysis of the redox processes during oxygen/anoxia transitions has proved to be an adequate method for identifying and following three fundamental intracellular redox compartments: (1) the respiratory system, (2) the microsomal system, and (3) the glycolytic system. The provision of substrates and/or suitable inhibitors has allowed the description of functional interrelationships within the mitochondrial and the cytoplasmic spaces. The ouabain major site of response has been located on the cytosolic pyridine nucleotides, with a very small response in the mitochondrial space. The switching on and off of substantial fractions of the NAD(P)+/NAD(P)H and Fpoxidized/Fpreduced pools has been observed, which helps to clarify the large phase shift between the overall pyridine nucleotide and flavin oxidation-reduction processes, during the cycle of the spontaneously beating heart and during skeletal muscle contraction and recovery, here originally prompted out.

Renal and hemodynamic effects of atrial natriuretic peptide infusion are not mediated by peripheral dopaminergic mechanisms

The possible involvement of peripheral dopaminergic mechanisms in the action of atrial natriuretic peptides was investigated in 10 subjects by administering 200 micrograms h-ANP 99-126 intravenously for 30 min during treatment with 50 mg carbidopa, a peripheral inhibitor of dopamine synthesis, every 8 h, or during placebo. Atrial natriuretic peptide (ANP) infusion during placebo was associated with a significant increase of diuresis, natriuresis, kaliuresis, urinary noradrenaline, and dopamine excretion. Plasma aldosterone significantly decreased. Blood pressure was slightly reduced. The administration of carbidopa significantly reduced urinary dopamine excretion but did not modify natriuresis, diuresis, indexes of adrenergic and renin-aldosterone system activity, blood pressure, or heart rate, both in basal conditions and in response to ANP infusion. We conclude that the effects of exogenous ANP administration are independent from dopaminergic mechanisms that involve the synthesis of dopamine outside the central nervous system, particularly in the kidney.

[Stellate ganglion block in the treatment of ischemic syndrome in an upper limb due to accidental intra-arterial injection of pharmacologic substances or narcotics]

The paper describes five cases of accidental intraarterial injection of pharmacological drugs (diazepam or thiopentone) or dope (heroin) in an upper limb. Following a review of the physiopathological mechanisms which led to ischemic damage, the Authors outline a protocol of continuous pharmacological sympathicolysis in the affected limb, using repeated anesthetic blocks of the homolateral stellate ganglion.

[Increase by ANP and ADH of the duration of activation and deactivation of the cardiopulmonary baroreceptor reflex: modification in the presence of left ventricular hypertrophy]

The involvement of cardiopulmonary and arterial sinoaortic receptors in the control of antidiuretic hormone (ADH) and atrial natriuretic peptide (ANP) release is still controversial in humans. Moreover, it is not clear if this control may be impaired in hypertensive patients with left ventricular hypertrophy (LVH). We studied 17 male subjects, age 18-58 (6 normotensives and 9 mild hypertensives, 5 without and 4 with LVH). Each subject underwent selective loading and unloading of cardiopulmonary receptors, in a randomized sequence, by application of a positive (LBPP) or negative (LENP) pressure to the lower body (steps: +10, +20, +40, -10, -40 mmHg, each for about 30 min), through a plexyglass-constructed tubular apparatus with a rubber adhesion round the patients' waist. Blood samples were taken at the end of every step for measurement of ADH, ANP, PRA, immunoreactive renin, aldosterone, noradrenaline and adrenaline. Cuff arterial pressure was measured every 5 min, while heart rate was evaluated by continuous ECG recording. Hypertensive subjects underwent right atrial pressure measurement by an iv catheter and forearm blood flow evaluation at rest and during the different steps (venous occlusion plethysmography). During LBNP, ADH plasma levels increased progressively, but the increase became statistically significant only at the step of -40 mmHg. ANP increased significantly during LBPP. Taking into account only hypertensive patients, a consistent reduction in the changes of ADH and ANP plasma levels, respectively during LBNP and LBPP in patients with LVH in respect to those without LVH was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrical stimulation of the motor cortex: theoretical considerations

The aim of this paper is to present the results of a theoretical analysis of the intracranial fields produced by electrical stimulation of the unexposed motor cortex with surface electrodes in humans. Simulations of a first approximation model of the head indicate that the intensity and the spatial configuration of the intracranial fields can be controlled, to a great extent, by proper choice of the location and of the number of the stimulating electrodes. Fields are shown to be reasonably insensitive to changes of some crucial parameters, like the number of the stimulating electrodes and the ratio between the conductivity of the skull and that of the other tissues.

Neuromagnetic functional localization: principles, state of the art, and perspectives

The neuromagnetic method has been providing impressive results in the understanding of the functions and of some pathologies of the human brain. The possibility of achieving three-dimensional source localization represents a fundamental step forward in the study of the organization of cortical areas, in that of focal disorders and, in general, in the investigation of brain information processing. The development of large multichannel systems to achieve real time functional localization is being carried on in several countries and the first prototypes are already operating for a full assessment of the benefits of the technique. The use of time-varying magnetic pulses provides the opportunity for non-invasive stimulation of the central nervous system toward the achievement of functional imaging of the motor cortices.

Brain stem neurons projecting to neocortex: a HRP study in the cat

The cortical projections of the brain stem were investigated in detail in the cat by means of the horseradish peroxidase (HRP) retrograde axonal transport. Most of the cells providing ascending fibers to the neocortex were located in the pons (locus coerulus and related structures, central gray substance, dorsal tegmental nucleus, raphe nuclei, reticular nuclei); labeled neurons were also identified in the mesencephalon, mainly in the periaqueductal gray and in the nucleus linearis rostralis. These projections, and particularly the pontine fibers, were diffusely distributed throughout the cerebral cortex.