Non-cultured cell transplantation in an ovine model of non-ischemic heart failure.

OBJECTIVE: Cell therapy may be a promising alternative or adjunct to current treatment modalities for ischemic heart failure. But little is known on the impact of myogenic cell transplantation in large animal models of non-ischemic cardiomyopathy. The aim of the present study was to explore whether an ovine model of toxin-induced heart disease could benefit from non-cultured skeletal muscle cell transplantation. METHODS: Sequential intracoronary injections of doxorubicin (0.75 mg/kg) were carried out every 2 weeks until echocardiographic detection of myocardial dysfunction. Sheep were then randomly assigned to either non-cultured cell transplantation (n=8) or placebo injection (n=5). For the cell therapy group, a skeletal muscle biopsy (about 10 g) was explanted from each animal approximately 3h before grafting. After thoracotomy, 20 epicardial injections were carried out. The animals were assessed one last time before sacrifice, 2 months after the thoracotomy. Cells were tracked with cmDiI (red fluorescence) and characterized with immunohistochemistry with monoclonal antibodies to a fast skeletal isoform of myosin heavy chain. RESULTS: Two months after intramyocardial grafting, tissue Doppler imaging and conventional echocardiographic assessment of the groups showed a marked improvement in the non-cultured cell therapy group. Ejection fraction (EF) (p<0.05) as well as systolic endocardial velocities (p<0.01) improved versus the placebo group. CmDiI and skeletal myosin heavy chain expression was detected in all animals at 2 months after implantation confirming engraftment of skeletal muscle cells. CONCLUSIONS: In conclusion, our data indicate that non-cultured muscle cell transplantation is feasible and may translate into a functional benefit in an ovine model of dilated heart failure.     

Hypertension following renal transplantation in children

The files of 334 consecutive cadaver kidney (CK) and of 27 living related (LR) transplantations (T) in children and adolescents performed from 1973 to 1984 have been reviewed. Following cadaver transplantation, 52 patients (15%) never had hypertension (HT), 41 patients (12%) had only initial HT up to 6 months after transplantation and 18 other patients (5%) exhibited transient HT episodes while on high-dose steroid therapy. Finally, 209 patients (62%) had HT for periods longer than 6 months and 16 patients (5%) until death or graft failure within the first 3 months. Chronic graft rejection was the major cause of HT, but other factors either isolated or in association were also present. Renal artery stenosis (RAS) was diagnosed in 43 cases (13%) 2–17 months post-transplantation; 10 of these were operated upon (5 successfully) and 9 underwent transluminal angioplasty with a single success. Nine cases of RAS resolved spontaneously. HT was attributed to the host kidney in 10 cases (3%) and to recurrence of primary renal disease in 9 (3%). HT observed after CKT was sometimes severe and difficult to control. Acute complications from HT were recorded in 35 cases, with 6 deaths and 2 severe neurological sequelae. Among 25 LRT, 11 cases (40%) had no HT 13 (48%) had HT for longer than 6 months. In this group, no case of RAS was observed and only one complication (without sequelae) was noted. In conclusion, HT is a frequent and sometimes severe complication post-transplantation in children and adolescents.     

Alternative methods to analyse the impact of HIV mutations on virological response to antiviral therapy

Background  

Principal component analysis (PCA) and partial least square (PLS) regression may be useful to summarize the HIV genotypic information. Without pre-selection each mutation presented in at least one patient is considered with a different weight. We compared these two strategies with the construction of a usual genotypic score.     

Neutralizing antibodies in gene-defective hosts

In a host with a normal immune system and a complete gene defect, the nondefective gene product will be immunogenic. Consequently, neutralizing antibodies against the respective protein can arise either 'spontaneously' or after immunization, as shown in patients and in animal models, such as knockout mice. Accordingly, patients with X-linked or homozygous autosomal gene defects are at risk of developing neutralizing antibodies, in particular after protein substitution or gene therapy. This Review compares and exemplifies the various genetic and immunological contexts that lead to 'neutralizing and generated by gene defect' or 'nagged' antibodies, and outlines implications and solutions for therapeutic strategies.     

Estimation of dynamical model parameters taking into account undetectable marker values

Background  

Mathematical models are widely used for studying the dynamic of infectious agents such as hepatitis C virus (HCV). Most often, model parameters are estimated using standard least-square procedures for each individual. Hierarchical models have been proposed in such applications. However, another issue is the left-censoring (undetectable values) of plasma viral load due to the lack of sensitivity of assays used for quantification. A method is proposed to take into account left-censored values for estimating parameters of non linear mixed models and its impact is demonstrated through a simulation study and an actual clinical trial of anti-HCV drugs.     

The muscular membrane and calcium activation of the contractile system of a lamellibranch smooth muscle (ABRM)

1. Thin bundles of fresh ABRM treated by EDTA solution or Triton x-100 0.1% can be brought like glycerol-extracted fibres through contraction-relaxation cycles by changing the free Ca2+ level of the bathing medium for 10-6 M to 10-9 M. The kinetics of isometric force development and relaxation has been studied in the two conditions i.e ionic strength 0.06 pH 6.5 and ionic strength 0.28, pH 7.0 which are known to induce the catch-state in glycerol extracted fibres. When the low Ca-2+ solution (10-9M) is substituted for the high Ca-2+ solution (10-6M) immediately after the maximal force has been developed, relaxation occurs at a higher rate at ionic strength 0928 and pH 6.5. In this last condition, no tension redevelops after a quick release applied during the slow relaxation. 2. During the plateau, in presence of Ca-2+ 10-6 M. a quick release applied at any time is followed by a large redevelopment of tension at ionic strength 0.06 and pH 6.5. At ionic strength 0.28 and pH 7.0, the tension redevelops only during the decreased from 10-6 to 10-9 M without any change in the time course of the tension maintained. 3. These results suggest that in EDTA and Triton X-100 treated fibres of Abrm, the catch-state is spontaneously induced after the activation of the contractile mechanism under the same conditions of ionic strengh and pH as in glycerol extracted fibres. However, in the EDTA and Triton treated fibres, the presence of a high free Ca-2+ level is not necessary to maintain the tension in the catch-state induced at ionic strength 0.28 and pH 7.0.     

Deficient expression of enhanced reactivation of parvovirus H-1 in ataxia telangiectasia cells irradiated with X-rays or u.v. light

Cells of patients with ataxia telangiectasia (AT), an inheriteddisease characterized by a high propensity to cancer, are hypersensitiveto ionizing radiation. We investigated whether the hyper-radiosensitivityof AT cells correlated with a defect in their constitutive and/orconditional ability to rescue a damaged exogenous virus. Forthat purpose, parvovirus H-1, a single-stranded DNA virus whoseintranuclear replication mostly relies on host cell functions,was used as a probe. The survival of u.v.-or -irradiated H-1was measured in X-, u.v.- or mock-irradiated human cells ofnormal (NB-E) or AT (AT5BIVA) origin. -irradiated H-1 survivedto similar extents in untreated normal and AT cell lines. BothX- and u.v.-irradiatlon induced normal cells to achieve an enhancedreactivation (ER) of -- or u.v.-damaged H-1. In contrast, neitherdose-effect curves nor time course revealed significant levelsof ER expression after X- or u.v.-irradiation in AT5BIVA cells.Our results suggest that the impairment of ER of damaged parvovirusesmay constitute a marker of the AT cell phenotype and be relatedto the radiosensitivity of AT cells.