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Quasi-static boundary value problems are formulated for the isothermal linear theory of swelling porous elastic soils in the case that the fluid is incompressible. First, some general theorems (uniqueness, reciprocal and continuous dependence) are established in the general case. Then, in the case that solid matrix is saturated with fluid and occupies a semi-infinite cylinder of smooth cross section, a time-weighted cross-sectional area measure is used in order to establish spatial decay estimates for the quasi-static solutions. [ABSTRACT FROM AUTHOR]

Presents the outcome of a survey on risk perception, knowledge and attitudes towards HIV infection among pregnant women in France from December 1987 and March 1988. Offering of free testing for HIV antibodies; Respondents' socio-cultural characteristics; Attitudes toward HIV-testing; Knowledge of mother-to-child HIV transmission; Attitudes toward abortion.

Malignant ventricular arrhythmias (VA) may happen remote from tetralogy of Fallot (TOF) repair. Monomorphic ventricular tachycardia (VT) using surgical scar-related reentry circuits is the most common form of VA, but ventricular fibrillation (VF) unrelated to VT has been described. Right ventricular fibrosis may be part of the substrate for VF and also VT. We aimed to assess right ventricular fibrosis in young children with TOF. Methods We prospectively included 9 children requiring surgery for the management of TOF. Right ventricle tissue of the outflow tract resected during surgery was analyzed under conventional microscopy. Results Surgical indications were complete repair of TOF with pulmonary stenosis (n=7), complete repair with right-ventricle-to pulmonary-artery-conduit of TOF with pulmonary atresia (n=1) and redo surgery for outflow tract and pulmonary valve stenosis six years after the complete repair (n=1). Median age at complete repair was 5.5 months old (range: 3 to 75, 3 children coming from developing countries having been operated after 2 year-old). Median Sp02 was 85% (range: 65 to100%). Pulmonary annulus section was required in 62.5%. Morphological analysis revealed a marked sub-endocardial fibrosis, fibrosis of the interstitium and of the support vessels. Morphology of cardiomyocytes suggests that they remain immature in most cases. However, an early maturation was observed in some myocardial sectors in a 27-month-old child with cardiomyocytes exhibiting acquisition of a mature brick-wall micropattern. Cardiomyocytes are often multinucleated with some being trinucleated. MIB-1 revealed some cardiomyocytes to be in mitosis cycle. Conclusion Early fibrosis and cardiomyocytes alterations of the right ventricle outflow tract before any surgery in TOF are already present in very young children. If these early abnormalities are evolutive and if they represent a facilitating substrate for late VA remains to be demonstrated. [ABSTRACT FROM AUTHOR]

Introduction: The role of autonomic nervous system (ANS) on heart function modulation is well-known. By contrast, ANS role on myocardial tissue architecture has scarcely been investigated. The aim of the present work was to investigate changes in heart tissue architecture after chemical sympathetic denervation by 6OH-Dopamine (6OH-DA) in mice. Methods: Two months old mice (n=18) received 3 injections of 6OHDA (200mg/kg, ip) or saline (n = 6) at 3 days of interval. At 15 and 30 days after first injection, ECG was recorded (PowerLab, DSI) under anaesthesia and heart rate spectral variability (HRV) was performed (FFT) in low frequency (LF: 0.15-1.5Hz) and high frequency (HF: 1.5-5Hz) ranges; LH/HF ratio was also calculated. After sacrifice, blood was withdrawn for plasma catecholamine determination (HPLC). Heart tissue was fixed (formaldehyde 10 %) for histology or frozen for western blot analysis (tyrosine hydroxylase, TH). Results: When compared to controls (1410±145 pg/ml) plasma norepinephrine levels were significantly lower at D15 (766±186 pg/ml) and D30 (675±288 pg/ml) after 6OH-DA without significant change in epinephrine levels. TH expression was absent at D15 and present but significantly lower than in controls at D30. When compared to controls (48.5±6.2 %), LF HRV was significantly reduced at D15 (31.6±5.4 %) but not at D30 (58.2±16.2 %) without any change in HF. LF/HF ratio was lower in 6OH-DA treated mice at D15 (0.49±0.13 vs 1.29±0.17 in controls) but was normal at D30 (1.63±0.31). At D15, hearts from 6-OH-DA treated mice exhibited mild structural abnormalities with wavy cardiomyocyte appearance in septum. At D30, histological abnormalities concerned whole myocardium with myocytes intersecting at various angles with bundles wavy appearance. Variability in cell size with anisocaryosis, attenuated myocytes with perinuclear halo and shaped nuclei were observed. No inflammation, interstitial fibrosis or necrosis were noticed. Conclusion: This study suggests that heart denervation induces myocardial tissue disorganization. Relationship between these pathological changes and sympathetic nerve destruction and/ or catecholamine depletion remains to be elucidated. Apart from physiological significance, these results also bring new structural basis to explain increased risk of cardiac disease during human autonomic failure. [Copyright &y& Elsevier]

Background: Ephrin-B1 is a ligand from Eph/Ephrin family involved in cell-cell interactions. If the role of ephrine molecules is well known in embryonic tissue, their expressions/functions in adults remain unclear and to date, no study have paid attention to their potential implication in heart physiopathology. Aim: To characterize the cardiac phenotype of ephrin-B1 knockout mice. Methods: Two months old-mice were analyzed. Heart tissue was fixed (formaldehyde 10 %) and embedded in paraffin for immunohistochemistry or frozen for western-blot (WB) analysis. Immunofluorescence (IF) studies were performed on heart cryosections. ECG was recorded (PowerLab, DSI) under isoflurane anaesthesia and heart rate spectral variability (HRV) was performed (FFT) in low frequency (LF: 0.15-1.5 Hz) and high frequency (HF: 1.5-5 Hz) ranges ; LH/HF ratio was also calculated. Results: We first assessed expression of Ephrin-B1 by WB in heart from WT animals. A specific band around 47 kDa was detected in WT heart total protein extracts that was lost in KO mice. Further IF studies demonstrated broad expression of Ephrin-B1 protein throughout all heart compartments with different cellular localizations (cardiomyocytes and micro/macrocirculation). Hematoxylin-eosin (HE) staining of paraffinembedded heart sections from KO mice revealed loss of organized cardiac tissue characterized by the presence of wavy cardiomyocytes in both septum and ventricles. Myocytes intersected at various angles with bundles wavy appearance. No inflammation, interstitial fibrosis or necrosis were noticed. These pathological observations correlated well with the lack of stiffness of hearts from KO mice compared with controls. When we examined ANS-dependent heart rate variability, LFHRV was significantly reduced in KO mice (16.3±1.2 %) when compared to controls (48.5±6.2 %) without any change in HF, suggesting a specific loss of cardiac sympathetic innervation in these animals. LF/HF ratio was lower in KO mice (0.6±0.2 vs 1.3±0.2 in controls). Conclusion: This study provides the first evidence for the presence of ephrin molecules in the adult heart tissue with a specific expression of Ephrin-B1 ligand. The use of ephrin-B1 genetic mouse model highly suggests a role for ephrin-B1 in heart tissue architecture and in sympathetic control of heart rate variability. [Copyright &y& Elsevier]