Studies on the Bottom-Up and Top-Down Neural Information Flow Alterations in Neurodegeneration

BACKGROUND

A proper explanation for perceptual symptoms in neurodegenerative disorders including Alzheimer's disease and Parkinson's disease (PD) is still lacking.

OBJECTIVE

This study aimed at investigating the imbalance between 'bottom-up' and 'top-down' information flow (IF) and processing in PD in relation with visual hallucination symptoms.

METHODS

Here, we looked at bottom-up and top-down IF markers using resting state electroencephalographic (EEG) data from PD patients analyzed through three different IF measures (direct Directed Transfer Function (dDTF), full frequency Directed Transfer Function (ff-DTF), and renormalized Partial Directed Coherence (rPDC).

RESULTS

We observed an increased gamma band IF and a reduced beta band IF in PD patients compared to healthy controls. Additionally, we noticed a reduced theta band IF in PD patients using dDTF as a measure of IF. By source localizing the EEG activity of the PD patients and healthy controls, we looked at the alterations of IF in the prefrontal cortex of PD patients as well.

CONCLUSION

In line with previous studies, our results suggest that the delicate balance between bottom-up and top-down IF is disrupted in Parkinson's disease potentially contributing to the cognitive symptoms of PD patients.

Comparative Analysis of Neural Network Training Methods in Real-time Radiotherapy

BACKGROUND

The motions of body and tumor in some regions such as chest during radiotherapy treatments are one of the major concerns protecting normal tissues against high doses. By using real-time radiotherapy technique, it is possible to increase the accuracy of delivered dose to the tumor region by means of tracing markers on the body of patients.

OBJECTIVE

This study evaluates the accuracy of some artificial intelligence methods including neural network and those of combination with genetic algorithm as well as particle swarm optimization (PSO) estimating tumor positions in real-time radiotherapy.

METHOD

One hundred recorded signals of three external markers were used as input data. The signals from 3 markers thorough 10 breathing cycles of a patient treated via a cyber-knife for a lung tumor were used as data input. Then, neural network method and its combination with genetic or PSO algorithms were applied determining the tumor locations using MATLAB© software program.

RESULTS

The accuracies were obtained 0.8%, 12% and 14% in neural network, genetic and particle swarm optimization algorithms, respectively.

CONCLUSION

The internal target volume (ITV) should be determined based on the applied neural network algorithm on training steps.

Adsorption of Dissociating Aromatic Compounds by Activated Carbon: Effects of Ionization on the Adsorption Capacity

The adsorption of three dissociating aromatic compounds on an untreated commercially available activated carbon was investigated systematically. All adsorption experiments were carried out in pH-controlled aqueous solutions. The experimental isotherms were analyzed using the homogeneous Langmuir model. The effects of surface heterogeneity were investigated via the theory of localized physical adsorption, using the Langmuir equation as the local isotherm equation and assuming a Gaussian adsorption energy distribution. A new method of utilizing the extracted parameters from the homogeneous and heterogeneous models is presented. This new approach provided a better understanding of the change in monolayer capacity and other adsorption characteristics of a carbon/solute system with pH.

Enhanced Film Blowing of Polylactide by Incorporating Branched Chains and Stereocomplex Crystals

Chain architecture is an influential parameter in melt processing of polymeric material. In this study effect of different chain structures on polylactide (PLA) film blowing process and on the final film properties was investigated. Blends of linear PLA with three branched poly(L-lactide)s with 4-arms star shaped, comb like and hyper branched structures were prepared by twin screw extruder. In another series of blending, poly(D-lactide) of these branched structures were used to obtain stereocomplex crystal. Operating window of blends were determined in a series of film blowing process experiments with different blow up and take up ratio and results were compared to linear PLA as a reference. Moreover, different characterization techniques were applied to determine the properties of produced films. It was found that addition of branched architecture and presence of stereocomplex in a linear PLA matrix result in a greater operating window for film blowing and improve mechanical and crystallization properties of blown films.

[Double fungemia. Report of four Tunisian cases]

Fungemia is classically caused by a single species and the detection of more than one species in blood samples is uncommon. We report four cases of mixed fungemia (MF) diagnosed in the parasitology-mycology laboratory of Farhat-Hached hospital in Sousse, Tunisia. The MF episodes occurred in two neonates and two adults suffering from acute myeloid leukemia. Two fungal species were detected concomitantly within the same blood culture in all cases. Species combination was detected by the subculture of the blood culture on Candida ID(®) chromogenic medium in three cases and on Sabouraud agar in one case. Predisposing factors were: indwelling catheters (4/4), broad-spectrum antibiotics (3/4), neutropenia (2/4), exclusive parenteral nutrition (2/4) and Candida colonization (1/4). Patients presented febrile sepsis with no response to broad-spectrum antibiotic therapy in all cases. Outcome under antifungal treatment was favorable in two cases and the two other patients died.

CONCLUSION

MF appears similar to the more common monomicrobial fungemia. The use of chromogenic media in routine can improve the detection of MF episodes allowing appropriate antifungal therapy.

Neonatal invasive candidiasis in Tunisian hospital: incidence, risk factors, distribution of species and antifungal susceptibility

The aim of our study was to assess epidemiological features of neonatal invasive candidiasis in Farhat Hached hospital of Sousse, Tunisia, including incidence, risk factors, mortality, species distribution and antifungal susceptibility. Laboratory data from 1995 to 2010 and medical records of 127 invasive candidiasis cases were reviewed. We tested the susceptibility of 100 Candida sp isolates by using ATB fungus(®) 3 and to fluconazole by using E-test(®) strips. A total of 252 cases of neonatal invasive candidiasis occurred over the study period. The incidence increased 1.8-fold from 1995 to 2006 and decreased fourfold from 2007 to 2010. Candida albicans was the predominant species up to 2006 and a shift in the species spectrum was observed with increase of the non-albicans species mainly C. parapsilosis. The agreement between the ATB Fungus(®) and the E-test(®) for determining fluconazole susceptibility was high. All tested isolates were susceptible to fluconazole, flucytosine, amphotéricine B and voriconazole and the itraconazole resistance rate was 5%. The mortality rate was 63%. The invasive candidiasis incidence increased from 1995 to 2006 and decreased from 2007 to 2010. The spectrum of Candida species and the lack of fluconazole-resistant strains argue for the usefulness of fluconazole as an empiric treatment.

The experimental and theoretical QM/MM study of interaction of chloridazon herbicide with ds-DNA

We report a multispectroscopic, voltammetric and theoretical hybrid of QM/MM study of the interaction between double-stranded DNA containing both adenine-thymine and guanine-cytosine alternating sequences and chloridazon (CHL) herbicide. The electrochemical behavior of CHL was studied by cyclic voltammetry on HMDE, and the interaction of ds-DNA with CHL was investigated by both cathodic differential pulse voltammetry (CDPV) at a hanging mercury drop electrode (HMDE) and anodic differential pulse voltammetry (ADPV) at a glassy carbon electrode (GCE). The constant bonding of CHL-DNA complex that was obtained by UV/vis, CDPV and ADPV was 2.1×10(4), 5.1×10(4) and 2.6×10(4), respectively. The competition fluorescence studies revealed that the CHL quenches the fluorescence of DNA-ethidium bromide complex significantly and the apparent Stern-Volmer quenching constant has been estimated to be 1.71×10(4). Thermal denaturation study of DNA with CHL revealed the ΔTm of 8.0±0.2°C. Thermodynamic parameters, i.e., enthalpy (ΔH), entropy (ΔS°), and Gibbs free energy (ΔG) were 98.45 kJ mol(-1), 406.3 J mol(-1) and -22.627 kJ mol(-1), respectively. The ONIOM, based on the hybridization of QM/MM (DFT, 6.31++G(d,p)/UFF) methodology, was also performed using Gaussian 2003 package. The results revealed that the interaction is base sequence dependent, and the CHL has more interaction with ds-DNA via the GC base sequence. The results revealed that CHL may have an interaction with ds-DNA via the intercalation mode.

[Comparing two Prepidil gel regimens for cervical ripening before induction of labor at term: a randomized trial]

OBJECTIVES

To compare efficacy and safety of two regimens of intracervical dinoprostone (Prepidil) in cervical ripening before labor induction at term.

PATIENTS AND METHODS

This was a prospective randomized clinical study including 148 patients with single pregnancy, viable fetus at gestational age greater than 36 weeks gestation and a Bishop score less than five, who required induction of labor. Patients were randomised to receive either repeated doses of dinoprostone gel 0.5mg (Prepidil) every 6 hours (group I) or every 12 hours (group II) for maximum three times before inducing labor with Oxytocin. The main outcome was the rate of caesarean sections.

RESULTS

The two groups were similar in patient characteristics, indication for labor induction and preinduction Bishop scores. The caesarean rate was lower in group I (20.3%) than in group II (23%); though the difference did not reach statistical difference: p=0.69. Delivery rate in the first 24 hours was significantly higher in group I (62.2%) than in group II (40.5%); p=0.009. Prepidil secondary effects were experienced in 8.1% of patients in group I versus 1.4% in group II; p=0.11. Median umbilical artery pH at birth was 7.232+/-0.47 in group I and 7.294+/-0.58 in group II; p=0.30. Maternofetal infections rate was lower in group I (1.4%) than in group II (2.7%) without significant difference (p=0.56).

CONCLUSIONS

Repeated intracervical doses of Prepidil every 6 hours, in cervical ripening before labor induction at term, enables higher delivery rate in the first 24 hours without inducing excess of caesarean sections or maternofetal morbidity when compared to its administration every 12 hours.

Deceleration-dependent shortening of the QT interval: a new electrocardiographic phenomenon?

In clinical cardiology, deceleration-dependent QT interval shortening is considered to be an extraordinary electrocardiographic phenomenon. We present an early premature born 4-year-old African-American girl with complications related to her premature birth, developmental delay, and several episodes of cardiac arrest. An episode of severe transient bradyarrhythmia was documented on Holter monitoring. The unique feature of the rhythm strips was paradoxical gradual shortening of the QT interval to 216 ms with accompanying transient T-waves abnormalities. The activation of the Ik, ACh due to an unusually high vagal discharge to the heart is proposed as a possible mechanism responsible for both slowing of the heart rate and shortening of the QT interval.

Application of chronopotentiometry to determine the thickness of diffusion layer adjacent to an ion-exchange membrane under natural convection

A brief review of the evolution of the diffusion boundary layer (DBL) conception inspired by the works of Nernst, Levich and Amatore is presented. Experimental methods for studying the DBL in electrode and membrane systems are considered. The electrochemical behaviour of a CM2 cation-exchange membrane in NaCl and KCl solutions is studied by chronopotentiometry at constant under-limiting current. Chronopotentiometric curves are described theoretically by applying the Kedem-Katchalsky equations in differential form to a three-layer system including the membrane and two adjoining DBLs. The conductance coefficients entering the equations are found by treating the results of membrane characterisation: the electrical conductivity, transport numbers of ions and water, electrolyte uptake, as functions of the equilibrium electrolyte solution. The two-phase microheterogeneous model is used for this treatment resulting in presentation of the conductance coefficients as functions of (virtual) electrolyte solution concentration in the membrane. The steady-state DBL thickness (delta) is found by fitting experimental potential drop at sufficiently high times. It is found that delta is proportional to (Delta c)(-0.2), where Delta c is the difference between the electrolyte concentration in the solution bulk and at the interface. This result differs from the Levich equation, which gives the power equal to -0.25 for Delta c. This deviation is explained by the fact that the theory of Levich does not take into account microscopic chaotic convection motion recently described by Amatore et al. It is shown that the treatment of experimental chronopotentiometric curves with the model developed allows one to observe the role of streaming potential in the membrane. Different mechanisms of streaming potential and their effect on the shape of chronopotentiograms are discussed. A simple analytical solution of Navier-Stokes equations applied to natural convection near an infinite vertical ion-exchange membrane is found. It is shown that the formation of DBL induced by electric current is quasi-stationary. This fact allows the empirical expression found earlier and linking delta with Delta c under steady-state conditions to be used in transient regimes. The numerical solution of the non-stationary Kedem-Katchalsky equations together with this empirical expression results in quantitative description of the potential difference (pd) and delta as functions of time in chronopotentiometric experiments. The comparison of theoretical and experimental chronopotentiometric curves shows an excellent agreement, especially for the part after switching off the current. The reasons of a small deviation observed just before the curves attain steady state under a constant current applied are discussed.

[Acute renal failure in full term neonates with perinatal asphyxia. Prospective study of 87 cases]

BACKGROUND

Renal involvement is frequent in neonates with perinatal asphyxia. It is correlated with the severity of neurological damage and seems to worsen the long-term neurological outcome.

PURPOSE

The aim of this study was to determine the incidence of renal failure after perinatal asphyxia, to precise the relationship between severity of cerebral damage and renal failure and to evaluate the place of renal damage in the short- and middle-term neurological outcome.

POPULATION AND METHODS

We conducted a prospective study including 87 full-term neonates admitted in the neonatology department of F. Hached university hospital in Sousse (Tunisia) and suffering from hypoxic ischemic encephalopathy from 1st January 2003 to 30 June 2005. Renal function was assessed by measuring plasma urea and creatinine at age 48 h. Renal failure was defined by a level of creatinine above 90 micromol/l. Neurologic examination was performed on day 7. The survivors were followed up by the same senior after discharge.

RESULTS

During the study period, 87 full-term neonates were admitted for hypoxic ischemic encephalopathy. The degree of neurological impairment was determined according to Sarnat classification: 1st stage 9 neonates (10,3%), 2nd stage 67 (77%) and 3rd stage 11(12,6%). Renal failure involved 15 neonates (17,2%) of whom 10 belonging to the 2nd stage group. Renal function outcome was favorable in all survivors with normalisation of plasma creatinine level between day 5 and day 15. Eight neonates died, of whom 3 with renal failure. Neurologic examination was abnormal in 36 out of 72 (50%) neonates without renal failure and in 9 of the 12 (75%) survivors with renal failure. Among the 12 neonates with renal failure, 7 had abnormal neurologic features at discharge. Neurologic assessment between 6 and 18 months was abnormal in 4/12 (33%) of neonates with renal failure versus 8/72(11%) of neonates without renal failure.

CONCLUSION

Transient renal failure is commonly observed in perinatal asphyxia. Renal failure is correlated with neurologic severity. Renal function assessment using creatinine plasma level seems to be correlated with neurologic outcome. However, other tools appreciating renal function, namely tubular function, should be determined earlier in order to predict neurologic outcome after hypoxic ischemic encephalopathy.

Thrombose aortique néonatale majeure: à propos d'une observation

Aortic thrombosis is a rare and severe condition in neonates which often is revealed by ischemia of lower limbs. We report a case of major aortic thrombosis revealed by renal failure, hematuria and dehydration in a 10-day-old girl. Clinical features consisted in hypertension at upper limbs without ischemic signs of the lower limbs. Diagnosis was made using renal Doppler ultrasound. Thrombosis resolved after thrombolytic treatment and anticoagulation using heparin. The case report is followed by a review of the literature dealing with clinical, etiological and therapeutic aspects of neonatal arterial thrombosis.

[Eosinophilic granuloma revealed by torticollis: a case report]

Langerhans cell histiocytose is a rare condition in childhood. It presents in different ways ranging from a single bony disease to a multisystemic disease involving vital organs.

CASE REPORT

We report a case of single bone involvement revealed by torticollis in an eight-year-old boy. The diagnosis was evocated on radiological findings and confirmed by histologic aspects. After a period of 2,5 years, this child is in total spontaneous remission.

CONCLUSION

Torticollis must be explored and watched. Eosinophilic granuloma can be a rare aetiology in children. The outcome is often favorable.

[Prolonged fever in children. Retrospective study of 67 cases]

BACKGROUND

The first problem to face in prolonged fever is its etiologic diagnosis. Its incidence varies between 0,5 to 3% of all paediatric hospital-stay. Precise diagnosis need an extensive questionnary, complete physical examination and an algorithm of complementary exams.

PURPOSE

To precise the epidemiologic profile and causes of prolonged fever in a children.

POPULATION AND METHODS

Retrospective review of 67 children between two and 15 years old admitted in the general paediatrics department of the Fattouma Bourguiba university hospital in Monastir (Tunisia), for prolonged fever between 1(st) January 1988 and 31 December 1998.

RESULTS

The incidence of prolonged fever was 1,02%. The mean age was seven years with female predominance. The mean fever duration was 30 days. Fever was isolated in 23,9% of cases. Fever was associated to rheumatic or respiratory signs in respectively 26,9% and 20,9% of cases. Hospital-stay was of 11 days in 50% of cases. Prominent causes were dominated by infectious diseases (56,7%) with predominance of localized infections, followed by inflammatory diseases (20,9%) with predominance of rheumatic fever and neoplasms (3%). Fever remained of unknown origin was seen in 19,4% of cases.

CONCLUSION

Prolonged fever is still dominated by infectious and inflammatory diseases and depend on local epidemiological particularities. In fact we noted in this study the relative high-frequency of visceral leishmaniasis, complicated pulmonary hydatic cyst and rheumatic fever. The diagnosis approach should be based on complementary exams of first and second stage because of their high number and cost. Prognosis of fever of unknown origin is often favorable.

Selegiline in the treatment of Parkinson's disease: its impact on orthostatic hypotension

Less than a consensus exists as to whether chronic treatment with selegiline in combination with levodopa/carbidopa in patients with Parkinson's disease, is associated with more pronounced orthostatic hypotension than treatment with levodopa/carbidopa alone. To resolve this issue, we compared orthostatic tolerance and autonomic reflexes in 95 patients with Parkinson's disease treated chronically with either selegiline alone (n = 10), levodopa/carbidopa alone (n = 49) or both agents combined (n = 36). Supine heart rate and blood pressure, autonomic cardiovascular reflexes and the frequency and magnitude of orthostatic hypotension were similar in all three treatment groups.

Total synthesis and determination of the absolute configuration of coscinosulfate. A new selective inhibitor of Cdc25 protein phosphatase

The first total synthesis of coscinosulfate 1, a metabolite isolated from a sea sponge, starting from (+)-sclareolide 3 is described. The convergent synthesis strategy relies on the coupling of sulfone 21 with the bromide 26. The sulfone fragment 21 was obtained by successive asymmetric aldol reaction with aldehyde 2 to introduce the stereocenters at C-12 and C-13, followed by one-carbon homologation via Horner-Wadsworth-Emmons olefination. The selective sulfatation at C-12 was accomplished through the quinone intermediate 31 obtained by selective oxidation of hydroquinone 30; this, when followed by reduction, furnished the desired coscinosulfate 1. X-ray analysis of the intermediate aldehyde 18 confirmed the proposed structure.

Fetal nucleated red blood cells from CVS washings: an aid to development of first trimester non-invasive prenatal diagnosis

Fetal nucleated red blood cells (n-rbc) occur in the maternal circulation from 7 weeks of pregnancy. The enrichment of these cells from maternal blood will depend upon their stage of differentiation, which changes during development. We characterised the fetal n-rbc from chorionic villus sample (CVS) washings and used them to model first trimester non-invasive prenatal diagnosis. The ratio of epsilon- to gamma-globin-producing cells declined rapidly from 10 to 13 weeks, as did the ratio of nucleated to non-nucleated rbc. By 13 weeks the great majority of cells containing gamma- or epsilon-globin are anucleate. The fetal n-rbc were highly variable in size and density and sedimented over a wide density range with a high proportion (>80%) at a density overlapping with that of maternal rbc. We have devised an enrichment procedure using Orskoff lysis to differentially lyse the maternal cells followed by density centrifugation and separation using magnetic beads. This simple protocol allowed recovery of 70% (69+/-22%) of fetal cells when added at approximately 10 fetal cells/ml maternal blood. When 1 fetal cell/ml millilitre maternal blood was added (total volume 10 ml) the recovery was more variable but remained at approximately 70% (72+/-47%), with at least one fetal cell recovered in all cases.

H(2)-Broadening Coefficients in the nu(4) Band of NH(3)

H(2)-broadening coefficients have been measured for 66 rovibrational lines of NH(3) at room temperature in the (P)P and (R)P branches of the nu(4) band in the range 1470-1600 cm(-1), using a high-resolution Fourier transform spectrometer. The collisional widths are obtained by fitting Voigt profiles to the measured shapes of the lines. The broadening coefficients are found to decrease on the whole as J increases and they increase with K for a given J value. The results are compared with those calculated from a semiclassical model in which the inversion vibration of NH(3) and collision-induced transitions with DeltaK = 0 and DeltaK = +/- 3 are taken into account. The intermolecular potential used includes electrostatic, induction, and dispersion energy contributions. The calculations performed by considering only DeltaK = 0 transitions provide significantly lower broadenings but with a satisfactory J and K dependence. The same trends are obtained for the broadening coefficients in inversion-rotation transitions and in the Q branch of the nu(1) parallel band of NH(3). Copyright 2001 Academic Press.

Neocentromere formation in a stable ring 1p32-p36.1 chromosome

Neocentromeres are functional centromeres formed in chromosome regions outside the normal centromere domains and are found in an increasing number of mitotically stable human marker chromosomes in both neoplastic and non-neoplastic cells. We describe here the formation of a neocentromere in a previously undescribed chromosomal region at 1p32-->p36.1 in an oligospermic patient. Cytogenetic GTL banding analysis and the absence of detectable fluorescence in situ hybridisation (FISH) signals using telomeric probes indicate the marker to be a ring chromosome. The chromosome is negative for CBG banding and is devoid of detectable centromeric alpha satellite and its associated centromere protein CENP-B, suggesting activation of a neocentromere within the 1p32-36.1 region. Functional activity of the neocentromere is shown by the retention of the ring chromosome in 97% of the patient's lymphocytes and 100% of his cultured fibroblasts, as well as by the presence of key centromere binding proteins CENP-E, CENP-F, and INCENP. These results indicate that in addition to CENP-A, CENP-C, and CENP-E described in earlier studies, neocentromere activity can further be defined by CENP-F and INCENP binding. Our evidence suggests that neocentromere formation constitutes a viable mechanism for the mitotic stabilisation of acentric ring chromosomes.

Novel endogenous type D retroviral particles expressed at high levels in a SCID mouse thymic lymphoma

A xenograft model of the human disease Langerhans cell histiocytosis (LCH) was investigated with severe combined immunodeficiency (SCID) mice. Transplantation of human LCH biopsy material into SCID mice resulted in the generation of mouse tumors resembling lymphomas. A thymoma cell line (ThyE1M6) was generated from one of these mice and found to display significant levels of Mg2+-dependent reverse transcriptase activity. Electron microscopy revealed particles with type D retroviral morphology budding from ThyE1M6 cells at a high frequency, whereas control cultures were negative. Reverse transcription-PCR of virion RNA with degenerate primers for conserved regions of various mouse, human, and primate retroviruses amplified novel sequences related to primate type D retroviruses, murine intracisternal A particles, Jaagsiekte sheep retrovirus, and murine long interspersed nuclear elements but not other retroviral classes. We demonstrate that these sequences represent a novel group of endogenous retroviruses expressed at low levels in mice but expressed at high levels in the ThyE1M6 cell line. Furthermore, we propose that the activation of endogenous retroviral elements may be associated with a high incidence of thymomas in SCID mice.

Role of fetal echocardiography in the management of isolated fetal heart block with ventricular rate <55 bpm

Persistent bradycardia is an uncommon cardiac problem in fetuses but carries a high mortality in those with a ventricular rate <55 bpm. Fetal heart block is one of the most common causes of persistent fetal bradycardia (PFB). An optimal method for assessing and monitoring cardiovascular compensation in the setting of PFB due to heart block has not been fully established. We report the application of two-dimensional and Doppler echocardiography in close monitoring of cardiac function and hemodynamics in a third-trimester fetus with a ventricular rate <55 bpm due to heart block, which assisted in successful management of the pregnancy to term. Hemodynamic and cardiac adaptive changes in compromised fetuses, particularly due to heart block, are discussed.

Transthoracic Doppler echocardiography of normally originating coronary arteries in children

Transthoracic Doppler color flow and spectral velocity patterns of normal coronary arteries in children have not been well studied. We designed this study to evaluate coronary artery flow velocity characteristics in normal and hypertrophied hearts. Sixty-eight children with optimal two-dimensional echocardiographic images of the left coronary artery (LCA) and right coronary artery (RCA) were prospectively studied. The heart was normal in 45 children, and 23 had left and/or right ventricular hypertrophy assessed by echocardiography (mean age 5.8 versus 5.2 years, p = NS). Color flow signals were detected in the LCA in 63(92%) of the 68 children studied, and pulsed Doppler spectral waveforms were recorded in 47 (69%). The latter were recorded in 26 (58%) of 45 normal children and in 21 (91%) of 23 children with left ventricular hypertrophy. Diastolic RCA flow signals were detected mostly in those with right ventricular hypertrophy (10 of 10). Higher levels of LCA maximum diastolic velocity (42 +/- 23 versus 24 +/- 6 cm/sec, p = 0.0004), increased diastolic flow (16 +/- 15 versus 6 +/- 4 ml/min, p = 0.01), and delayed time to peak diastolic velocity expressed as a percentage of diastolic spectral duration (38% +/- 14% versus 20% +/- 8%, p = 0.0001) were observed in children with left ventricular hypertrophy than in those in normal children. A strong correlation was present between Doppler-derived LCA flow and left ventricular mass/m2 (r = 0.7, p = 0.001). In normal hearts, LCA spectral velocity pattern did not change with increasing age, but the time velocity integral became progressively larger, resulting in a strong correlation with weight (p < 0.001, r = 0.78). This study demonstrates (1) LCA flow signals can be detected and quantitated in the majority of children with and those without left ventricular hypertrophy. (2) Left ventricular hypertrophy is associated with increased LCA flow, higher diastolic velocity, and delayed peak diastolic velocity. (3) RCA flow signals are mostly detected when there is right ventricular hypertrophy. Studies on larger groups of patients are needed to further confirm our observations and to enhance understanding of coronary artery flow reserve.

Long-term follow-up results of balloon angioplasty of postoperative aortic recoarctation

Immediate- and short-term follow-up results of balloon dilatation of aortic recoarctation following surgery have been well documented, but there is sparse data on long-term follow-up. During a 10-year period ending in August 1995, 33 children, aged 2 months to 14 years old, underwent balloon angioplasty of aortic recoarctation. Prior surgery included resection and end-to-end anastomosis (n = 9), subclavian flap (n = 16) or prosthetic (Dacron or Gore-Tex) patch (n = 5) angioplasty, and repair of an interrupted aortic arch (n = 3). Recoarctation developed 1 month to 14 years (mean +/- SD 29 +/- 44 months) after surgery. The indications for angioplasty were peak-to-peak systolic gradients > 20 mm Hg and systemic hypertension and/or congestive heart failure. After balloon angioplasty, the peak-to-peak systolic pressure gradient across the coarctation decreased from 48 +/- 22 to 13 +/- 15 mm Hg (p <0.01), and the size of the coarcted segment increased from 3.3 +/- 1.4 to 6.5 +/- 2.3 mm (p <0.01). Follow-up angiography and/or magnetic resonance imaging were performed in 20 children 17 +/- 12 months after angioplasty. No aneurysms were observed and improvement in the diameter of the coarcted aortic segment (9 +/- 3 mm) persisted. One- to 10-year (median 5) clinical follow-up was available in 32 children. During follow-up, 2 children required surgery to repair a long tubular isthmic narrowing. The residual gradients, determined by arm-leg systolic blood pressure difference, were 5 +/- 8 mm Hg. No patient was symptomatic and only 1 patient (3%) was hypertensive, controlled with antihypertensive medications. We conclude that balloon angioplasty of aortic recoarctation following all types of surgical repair is feasible, safe, and effective with good long-term results. We recommend balloon angioplasty as the procedure of choice in the management of postsurgical recoarctation with hypertension and/or congestive heart failure.

Prevention of bacterial endocarditis: recommendations by the American Heart Association

OBJECTIVE

To update recommendations issued by the American Heart Association last published in 1990 for the prevention of bacterial endocarditis in individuals at risk for this disease.

PARTICIPANTS

An ad hoc writing group appointed by the American Heart Association for their expertise in endocarditis and treatment with liaison members representing the American Dental Association, the Infectious Diseases Society of America, the American Academy of Pediatrics, and the American Society for Gastrointestinal Endoscopy.

EVIDENCE

The recommendations in this article reflect analyses of relevant literature regarding procedure-related endocarditis, in vitro susceptibility data of pathogens causing endocarditis, results of prophylactic studies in animal models of endocarditis, and retrospective analyses of human endocarditis cases in terms of antibiotic prophylaxis usage patterns and apparent prophylaxis failures. MEDLINE database searches from 1936 through 1996 were done using the root words endocarditis, bacteremia, and antibiotic prophylaxis. Recommendations in this document fall into evidence level III of the US Preventive Services Task Force categories of evidence.

CONSENSUS PROCESS

The recommendations were formulated by the writing group after specific therapeutic regimens were discussed. The consensus statement was subsequently reviewed by outside experts not affiliated with the writing group and by the Science Advisory and Coordinating Committee of the American Heart Association. These guidelines are meant to aid practitioners but are not intended as the standard of care or as a substitute for clinical judgment.

CONCLUSIONS

Major changes in the updated recommendations include the following: (1) emphasis that most cases of endocarditis are not attributable to an invasive procedure; (2) cardiac conditions are stratified into high-, moderate-, and negligible-risk categories based on potential outcome if endocarditis develops; (3) procedures that may cause bacteremia and for which prophylaxis is recommended are more clearly specified; (4) an algorithm was developed to more clearly define when prophylaxis is recommended for patients with mitral valve prolapse; (5) for oral or dental procedures the initial amoxicillin dose is reduced to 2 g, a follow-up antibiotic dose is no longer recommended, erythromycin is no longer recommended for penicillin-allergic individuals, but clindamycin and other alternatives are offered; and (6) for gastrointestinal or genitourinary procedures, the prophylactic regimens have been simplified. These changes were instituted to more clearly define when prophylaxis is or is not recommended, improve practitioner and patient compliance, reduce cost and potential gastrointestinal adverse effects, and approach more uniform worldwide recommendations.

Prevention of bacterial endocarditis: recommendations by the American Heart Association

OBJECTIVE

To update recommendations issued by the American Heart Association last published in 1990 for the prevention of bacterial endocarditis in individuals at risk for this disease.

PARTICIPANTS

An ad hoc writing group appointed by the American Heart Association for their expertise in endocarditis and treatment with liaison members representing the American Dental Association, the infectious Diseases Society of America, the American Academy of Pediatrics and the American Society for Gastrointestinal Endoscopy.

EVIDENCE

The recommendations in this article reflect analyses of relevant literature regarding procedure-related endocarditis, in vitro susceptibility data of pathogens causing endocarditis, results of prophylactic studies in animal models of endocarditis and retrospective analyses of human endocarditis cases in terms of antibiotic prophylaxis usage patterns and apparent prophylaxis failures. MEDLINE database searches from 1936 through 1996 were done using root words endocarditis, bacteremia and antibiotic prophylaxis. Recommendations in this document fall into evidence level III of the U.S. Preventive Services Task Force categories of evidence.

CONSENSUS PROCESS

The recommendations were formulated by the writing group after specific therapeutic regimens were discussed. The consensus statement was subsequently reviewed by outside experts not affiliated with the writing group and by the Science Advisory and Coordinating Committee of the American Heart Association. These guidelines are meant to aid practitioners but are not intended as the standard of care or as a substitute for clinical judgment.

CONCLUSIONS

Major changes in the updated recommendations include the following: (1) emphasis that most cases of endocarditis are not attributable to an invasive procedure; (2) cardiac conditions are stratified into high-, moderate- and negligible-risk categories based on potential outcome if endocarditis develops; (3) procedures that may cause bacteremia and for which prophylaxis is recommended are more clearly specified; (4) an algorithm was developed to more clearly define when prophylaxis is recommended for patients with mitral valve prolapse; (5) for oral or dental procedures the initial amoxicillin dose is reduced to 2 g, a follow-up antibiotic dose is no longer recommended, erythromycin is no longer recommended for penicillin-allergic individuals, but clindamycin and other alternatives are offered.

Prevention of bacterial endocarditis. Recommendations by the American Heart Association

OBJECTIVE

To update recommendations issued by the American Heart Association last published in 1990 for the prevention of bacterial endocarditis in individuals at risk for this disease.

PARTICIPANTS

An ad hoc writing group appointed by the American Heart Association for their expertise in endocarditis and treatment with liaison members representing the American Dental Association, the Infectious Diseases Society of America, the American Academy of Pediatrics, and the American Society for Gastrointestinal Endoscopy.

EVIDENCE

The recommendations in this article reflect analyses of relevant literature regarding procedure-related endocarditis, in vitro susceptibility data of pathogens causing endocarditis, results of prophylactic studies in animal models of endocarditis, and retrospective analyses of human endocarditis cases in terms of antibiotic prophylaxis usage patterns and apparent prophylaxis failures. MEDLINE database searches from 1936 through 1996 were done using the root words endocarditis, bacteremia, and antibiotic prophylaxis. Recommendations in this document fall into evidence level III of the US Preventive Services Task Force categories of evidence.

CONSENSUS PROCESS

The recommendations were formulated by the writing group after specific therapeutic regimens were discussed. The consensus statement was subsequently reviewed by outside experts not affiliated with the writing group and by the Science Advisory and Coordinating Committee of the American Heart Association. These guidelines are meant to aid practitioners but are not intended as the standard of care or as a substitute for clinical judgment.

CONCLUSIONS

Major changes in the updated recommendations include the following: (1) emphasis that most cases of endocarditis are not attributable to an invasive procedure; (2) cardiac conditions are stratified into high-, moderate-, and negligible-risk categories based on potential outcome if endocarditis develops; (3) procedures that may cause bacteremia and for which prophylaxis is recommended are more clearly specified; (4) an algorithm was developed to more clearly define when prophylaxis is recommended for patients with mitral valve prolapse; (5) for oral or dental procedures the initial amoxicillin dose is reduced to 2 g, a follow-up antibiotic dose is no longer recommended, erythromycin is no longer recommended for penicillin-allergic individuals, but clindamycin and other alternatives are offered; and (6) for gastrointestinal or genitourinary procedures, the prophylactic regimens have been simplified. These changes were instituted to more clearly define when prophylaxis is or is not recommended, improve practitioner and patient compliance, reduce cost and potential gastrointestinal adverse effects, and approach more uniform worldwide recommendations.

Prevention of bacterial endocarditis. Recommendations by the American Heart Association

OBJECTIVE

To update recommendations issued by the American Heart Association last published in 1990 for the prevention of bacterial endocarditis in individuals at risk for this disease.

PARTICIPANTS

An ad hoc writing group appointed by the American Heart Association for their expertise in endocarditis and treatment with liaison members representing the American Dental Association, the Infectious Diseases Society of America, the American Academy of Pediatrics, and the American Society for Gastrointestinal Endoscopy.

EVIDENCE

The recommendations in this article reflect analyses of relevant literature regarding procedure-related endocarditis, in vitro susceptibility data of pathogens causing endocarditis, results of prophylactic studies in animal models of endocarditis, and retrospective analyses of human endocarditis cases in terms of antibiotic prophylaxis usage patterns and apparent prophylaxis failures. MEDLINE database searches from 1936 through 1996 were done using the root words endocarditis, bacteremia, and antibiotic prophylaxis. Recommendations in this document fall into evidence level III of the US Preventive Services Task Force categories of evidence.

CONSENSUS PROCESS

The recommendations were formulated by the writing group after specific therapeutic regimens were discussed. The consensus statement was subsequently reviewed by outside experts not affiliated with the writing group and by the Science Advisory and Coordinating Committee of the American Heart Association. These guidelines are meant to aid practitioners but are not intended as the standard of care or as a substitute for clinical judgment.

CONCLUSIONS

Major changes in the updated recommendations include the following: (1) emphasis that most cases of endocarditis are not attributable to an invasive procedure; (2) cardiac conditions are stratified into high-, moderate-, and negligible-risk categories based on potential outcome if endocarditis develops; (3) procedures that may cause bacteremia and for which prophylaxis is recommended are more clearly specified; (4) an algorithm was developed to more clearly define when prophylaxis is recommended for patients with mitral valve prolapse; (5) for oral or dental procedures the initial amoxicillin dose is reduced to 2 g, a follow-up antibiotic dose is no longer recommended, erythromycin is no longer recommended for penicillin-allergic individuals, but clindamycin and other alternatives are offered; and (6) for gastrointestinal or genitourinary procedures, the prophylactic regimens have been simplified. These changes were instituted to more clearly define when prophylaxis is or is not recommended, improve practitioner and patient compliance, reduce cost and potential gastrointestinal adverse effects, and approach more uniform worldwide recommendations.

Safety of rapid-rate transcranial magnetic stimulation: heart rate and blood pressure changes

We examined the influence of rapid-rate transcranial magnetic stimulation on heart rate and blood pressure in 13 healthy volunteers. In a first series three different cortical magnetic stimuli were applied: over C3, C4 and Fz (10/20 system), in a second series additionally over Pz. We also used a stimulus over the brachial plexus and a sham stimulus. Five stimuli of each location were applied with a Cadwell high speed magnetic stimulator using a focal point circular coil. Stimulus train duration was 500 ms, stimulus frequency 20 Hz. Stimulus strength was 70-90% of maximum stimulator output, 20% of maximum stimulator output above subjects' individual motor threshold. The subjects assessed stimulus inconvenience immediately after stimulation. ECG and blood pressure (Finapres) were recorded continuously during the 1 h test. In all subjects there was a clearly marked autonomic response with heart rate acceleration and decrease in blood pressure after all stimuli. There was no difference in responses between cortical stimuli. Blood pressure decrease after sham stimulation was significantly smaller than after cortical stimulation, it was more marked after brachial plexus stimulation. Autonomic reaction correlates well with subjective estimation of stimulus inconvenience. We conclude the observed effect of rapid-rate transcranial magnetic stimulation to be associated to rather an unspecific arousal reaction than to a direct stimulation of autonomic cortex areas. We did not observe any clinically relevant side-effects.

Acute results of balloon angioplasty of native coarctation versus recurrent aortic obstruction are equivalent. Valvuloplasty and Angioplasty of Congenital Anomalies (VACA) Registry Investigators

OBJECTIVES

This study sought to compare the immediate results and risk factors for suboptimal outcomes of percutaneous balloon angioplasty for native versus recurrent aortic obstruction.

BACKGROUND

Some cardiology centers have been reluctant to adopt balloon angioplasty for treatment of native aortic coarctation, while advocating balloon angioplasty over an operation for treatment of postsurgical or recurrent aortic obstruction.

METHODS

Acute results were analyzed from 970 procedures (422 native and 548 recurrent lesions) performed between 1982 and 1995 in 907 patients from 25 centers. An acute suboptimal outcome was defined as one or more of the following: residual systolic pressure gradient > or = 20 mm Hg, residual proximal to distal systolic pressure ration > or = 1.33 or a major complication (death, aortic transmural tear, stroke).

RESULTS

Bal loon angioplasty significantly (p = 0.0001) increased lesion diameter fo r both native (mean [+/= SD] 128 +/= 94%) and recurrent aortic obstruction (97 +/= 87%), with a significantly greater increase in the native group (p = 0.0001). A reduction in systolic pressure gradients was significant in both groups (p = 0.0001), but slightly higher (p = 0.01) for native (-74 +/- 24%) versus recurrent obstruction (-70 +/- 31%). Death associated with angioplasty was reported in 0.7% of patients with native and in 0.7% of patients with recurrent lesions (p = 1.00). An acute suboptimal outcome was noted with angioplasty in 19% of native and in 25% of recurrent lesions (p = 0.04). Significant independent risk factors included higher preangioplasty systolic gradient (odds ratio [OR] 1.39/10-mm Hg increment; 95% confidence interval [CI] 1.28 to 1.50, p = 0.0001), earlier study date (OR 0.92/1-year increment, 95% CI 1.02 to 1.26, p = 0.02) and recurrent obstruction (OR 1.39 vs. native lesions, 95% CI 1.00 to 1.94, p = 0.05).

CONCLUSIONS

Acute results and complications of balloon angioplasty of native coarctation appear to be equivalent or slightly superior to those of recurrent aortic obstructions.

Leukemia inhibitory factor and interleukin-6 are produced by diseased and regenerating skeletal muscle

The process of skeletal muscle regeneration following injury or disease involves locally produced growth factors which control cellular proliferation and differentiation. Leukemia inhibitory factor (LIF) and interleukin-6 (IL-6) have previously been shown to promote the proliferation of myoblasts in vitro, and thus may be involved in muscle regeneration. In the present investigation, the in vivo expression of these two myogenic growth factors was examined in regenerating muscle after a crush injury of wild type mice, and in diseased skeletal muscle and diaphragm of the mdxmouse. Using Reverse transcription polymerase chain reaction we have demonstrated that while normal muscle rarely expresses mRNA for these two molecules, there is significant up-regulation following injury, coinciding with the active period of muscle regeneration. This suggests these molecules act as locally produced trauma factors. This observation is reinforced in mdxmouse muscle, which is undergoing a cycle of degeneration and regeneration, and expresses both LIF and IL-6. Using in situ hybridization we have localized mRNA for LIF expression in the mdx diaphragm, suggesting that local production of these molecules by regenerating muscle itself, as well as by other cells in muscle, plays an important role in muscle regeneration.

Symptomatic heart disease in infants: comparison of three studies performed during 1969-1987

We compare the data of three studies of hospitalized infants with cardiac disease performed between 1967 and 1987. The studies were from the New England Regional Infant Cardiac Program (1967-1974), the Brompton Hospital (1973-1982), and the Northern Great Plains Regional Cardiac Program (1982-1987). Considering differences in classification among the studies, the distribution of cardiac anomalies during the first year of life is similar among the three studies. Although about 30% of infants are admitted during the first week of life and nearly 40% between 3 and 6 months, the proportion of infants admitted between 6 and 12 months was larger (25%) in the latest than in the earliest study (10%). There were also differences in the distribution of the diagnoses at various ages, reflecting changes in the patterns of care during the three eras.

Soluble antigen can cause enhanced apoptosis of germinal-centre B cells

Germinal centres are dynamic microenvironments of B-lymphocyte differentiation, which develop in secondary lymphoid tissues during immune responses. Within germinal centres, activated B lymphocytes proliferate and point mutations are rapidly introduced into the genes encoding their immunoglobulin receptors. As a result, new specificities of B cells are created, including those with a heightened capacity to bind the immunizing antigen. Immunoglobulin gene mutation can also lead to reactivity to self antigens. It has been suggested that any newly formed self-reactive B cells are eliminated within the germinal centre in order to avoid autoimmunity. Here we present evidence that antigen-specific, high-affinity, germinal-centre B cells are rapidly killed by apoptosis in situ when they encounter soluble antigen. The effect seems to act directly on the B cells, rather than through helper T cells. Furthermore, the apoptosis is unique to germinal-centre cells, and is only incompletely impeded by constitutive expression of the proto-oncogene bcl-2. This phenomenon may reflect clonal deletion of self-reactive B cells within germinal centres.

Reliability of echocardiography in the diagnosis of anomalous origin of the left coronary artery from the pulmonary trunk

Previous studies have indicated that the definitive diagnosis of anomalous origin of the left coronary artery from the pulmonary trunk (ALC) should be made by cardiac catheterization and angiography. This study evaluates echocardiography (two-dimensional, pulsed Doppler, and color flow mapping) as a method to establish the diagnosis of ALC. To diagnose ALC, a modified parasternal short-axis view was used to demonstrate continuity of the ALC with the pulmonary trunk and to detect the retrograde flow through the ALC into the pulmonary trunk. Absence of these imaging characteristics ruled out ALC. From June 1985 to January 1990, 16 patients who presented with or had previously had a dilated poorly contracting left ventricle were prospectively assessed by echocardiography to rule out ALC. Four patients had ALC (age 2 to 120 months, mean +/- 1SD = 32 +/- 59) and 12 patients (age 1 to 192 months, mean +/- 1SD = 57 +/- 80) had myocardiopathy. Two other patients with known ALC were evaluated by an observer unaware of the diagnosis. All coronary anatomy was confirmed by angiography, surgery, or autopsy. The correct diagnosis of coronary anatomy was obtained by echocardiography in all instances without false positive or false negative diagnosis of ALC. Three infants underwent surgical repair of ALC based only on the echocardiographic diagnosis. Echocardiography can be used to establish the diagnosis of ALC. Therefore surgical repair can be undertaken in some critically sick infants based on the echocardiographic diagnosis alone.

Pediatric cardiac rehabilitation

Sixteen patients participated in a Pediatric/Young Adult Cardiac Rehabilitation Program that included exercise training, education about cardiovascular diseases, dietary counseling, and counseling on stress management. Seven patients completed the program, and complete data were available on six. The subjects demonstrated significant changes in their hemodynamics and exercise tolerance after completing the program. Resting blood pressure decreased by 7%, from 119 +/- 12 to 111 +/- 10 mm Hg; peak oxygen consumption increased by 20%, from 31.9 +/- 4.3 mL/kg of body weight per minute to 38.4 +/- 6.0 mL/kg of body weight per minute; and exercise treadmill time increased by 21%, from 8.5 +/- 1.4 to 10.3 +/- 1.0 minutes. No complications occurred during exercise training or testing. Supervised exercise training at moderate intensity is safe and produces significant and beneficial changes in hemodynamics and exercise time in children with cardiac disease.