[Diabetic cardiac autonomic neuropathy]

Cardiac autonomic neuropathy (CAN) is a common complication of diabetes mellitus, which is associated with a higher risk of morbidity and mortality. It can be detected by analyzing spontaneous (Holter) or provoked (Ewing's test battery) changes in heart rate and arterial blood pressure. Baroreflex gain is a specific index of great interest. Our laboratory has acquired a large experience in the assessment of CAN in diabetic patients. We use the Finapres, a device that allows continuous noninvasive monitoring of blood pressure and heart rate, and a special and discriminative active orthostatic manoeuvre, the "squatting" test (standing-squatting-standing).

Les PCB dans l'environnement marin. Aspects géochimiques d'apports et de distribution. Cas du littoral français

Les PCB représentent un groupe de substances chimiques chlorées particulièrement rémanent dans l'environnement. La production mondiale cumulée est évaluée à 1 200 000 tonnes et environ 30 % de cette production sont dispersés dans l'environnement, essentiellement dans le milieu océanique. La distribution de ces substances dans l'environnement aquatique est fonction des mécanismes d'échanges aux interfaces eau/atmosphère, eau/sédiment, aux processus de transformation abiotiques et biotiques, et aux processus de bioconcentration dans les organismes vivants. Les travaux réalisés depuis une vingtaine d'années permettent de décrire assez précisément le cycle biogéochimique des PCB dans le milieu océanique. La contamination du milieu marin côtier français est examinée plus particulièrement. La production totale des PCB en France est estimée à 123 000 tonnes et les apports polluants vers le milieu marin côtier, par les fleuves et l'atmosphère, sont évalués entre 2,5 et 3,0 tonnes par an. Les zones côtières les moins touchées par la contamination des PCB sont localisées en Manche sur le littoral nord de la Bretagne jusqu'en Normandie (Ouest Contentin) et en Méditerranée sur le littoral est de la Corse. La zone la plus contaminée est l'estuaire et la baie de Seine qui reçoivent les apports contaminants fluviaux de la Seine. De fortes contaminations sont également observées dans les zones industrielles et urbaines, et dans les secteurs qui reçoivent les effluents urbains non traités (ex : Marseille).Plusieurs études réalisées régulièrement suggèrent une décroissance générale des niveaux de contamination le long du littoral français depuis une décennie.

La contamination des eaux continentales par les micropolluants organiques

Il y a environ 50 000 à 60 000 composés chimiques utilisés communément à des fins techniques. Certains d'entre eux sont toxiques et leur rejet dans l'environnement peut constituer une menace pour l'équilibre des écosystèmes aquatiques et pour la santé humaine. Plusieurs listes de substances dangereuses, appelées également polluants chimiques prioritaires, ont ainsi été établies par des organismes nationaux ou internationaux, notamment par l'EPA aux Etats-Unis, la CEE en Europe, l'Organisation Mondiale de la Santé (OMS). La nécessité de protéger les milieux aquatiques et la santé humaine a par ailleurs amené le développement de standards, de critères de qualité des eaux naturelles et des eaux potables, vis-à-vis de ces contaminants chimiques.

Les sources de pollution sont diverses, se partageant entre les sources localisées comme les effluents urbains et industriels et les sources diffuses comme les eaux de ruissellement en zones rurales et en zones urbaines et les retombées atmosphériques. Différentes processus biogéochimiques déterminent les mécanismes de transport et de transformation des polluants organiques dans le milieu aquatique, et la bioaccumutation dans les organismes vivants représente un important aspect de ce comportement.

Une première évaluation de la qualité des eaux continentales (rivières, lacs, eaux souterraines) est effectuée en examinant les données recueillies à travers le réseau de surveillance mondiale de la qualité de l'eau (GENS/EAUX) mis en place par deux organismes des Nations Unies, l'OMS et le PNUE. D'autres sources d'informations, publiées dans la littérature scientifique, ont été également utilisées pour évaluer les niveaux de concentrations observés pour différents groupes de polluants organiques dans les eaux naturelles et les eaux potables. La plupart des données disponibles proviennent d'un nombre limité de pays industriels d'Amérique du Nord, d'Europe et du Japon. Il y a une dramatique absence d'informations concernant la qualité chimique des eaux continentales dans les pays les moins développés d'Afrique, d'Amérique Latine et d'Asie. A l'heure actuelle, la stratégie de surveillance des polluants chimiques à l'échelle mondiale est donc loin d'être réellement satisfaisante.

[Evaluation after 20 years of a case of Takayasu's disease that presented with aortic regurgitation]

Takayasu's disease is a segmental multifocal affection of medium and large arteries. The diagnosis is based on the association of stenotic and aneurismal lesions of the aorta and its branches secondary to an inflammatory infiltration of the media and adventitia. Cases of aortic regurgitation associated with aneurismal dilatation of the ascending aorta as the presenting features of Takayasu's disease, as in this case, are rare. Histological examination of the aortic wall may help establish the diagnosis by showing signs of aortitis. The other usual arterial lesions are sometimes missing at the initial phase of the disease. A late histological diagnosis may be difficult as the inflammatory lesions tend to be progressively replaced by fibrotic lesions or a banal atheroma.

[Twelve years' experience with Carbomedics bileaflet valves]

The authors report long-term results of a cohort of patients who underwent valve replacement with a Carbomedics bileaflet mechanical prosthesis. The influence of patient age on the results was examined. Three hundred and ninety patients were operated between 1988 and 2000. Complete follow-up was available in 98.5% of cases. For aortic valve replacement, the total experience was 1,061 person-years. The hospital mortality was 2.3%. Global actuarial 12 year survival was 74 +/- 7%. The actuarial probability of absence of thrombo-embolic complications at 12 years was 95 +/- 3%, and of absence of haemorrhagic complications 89 +/- 4%. For mitral valve replacement, the total experience was 610 person-years. The hospital mortality was 3.4%. The global actuarial 12 year survival was 78 +/- 5%. The actuarial probability of absence of thrombo-embolic complications at 12 years was 79 +/- 9% and of absence of haemorrhagic complications 82 +/- 5%. The results of survival and prosthesis-related complications were comparable to those reported in the literature with second generation mechanical prostheses, with the exception of thromboses of the mitral valve for which a higher linear rate was observed. Multivariate analysis showed an increased (x 2.3) risk of haemorrhage after 60 years of age irrespective of the site of implantation of the prosthesis. In patients over 60 years of age, the risks of long-term anticoagulant therapy should raise questions concerning the modality of follow-up and the indications. The use of biological prostheses is a possible alternative.

Computerized single-breath nitrogen washout: predicted values in a rural French community

Comparative manual and computer measurements of the alveolar N2 slope and closing volumes have indicated systematic differences. When a computerized system is used in field surveys, predicted values are to be obtained under the same conditions. Therefore, we measured the alveolar nitrogen slope (phase III, PIII), closing volume (CV), and closing capacity (CC) from single-breath N2 washout maneuvers in 158 healthy subjects (68 females), ages 21 to 64 years, from a rural community living in a nonpolluted area of northeast France. PIII, the CV to vital capacity ratio (CV:VC, %), and the CC to the total lung capacity ratio (CC:TLC, %) were regressed against age, height, weight, and the body mass index (BMI, kg/m2) and prediction equations with 95% confidence intervals were computed. PIII increased with age in both sexes and tended to decrease with height in males (r = -0.19, p = .08). The CV:VC and CC:TLC ratios depended on age and, in males, increased with the BMI. Despite accepting a 15% difference between the test VC and the spirometric VC, only 46.3% of asymptomatic nonsmokers produced a valid single-breath nitrogen washout (SBN2) test. This high failure rate limits the usefulness of the test for epidemiologic purposes when older populations "naive" to pulmonary function testing are studied under field-survey conditions.

Immunisation of metastatic cancer patients with MAGE-3 protein combined with adjuvant SBAS-2: a clinical report

Fifty-seven patients with MAGE-3-positive measurable metastatic cancer, most of them with melanoma, were vaccinated with escalating doses of a recombinant MAGE-3 protein combined with a fixed dose of the immunological adjuvant SBAS-2, which contained MPL and QS21. The immunisation schedule included 4 intramuscular (i.m.) injections at 3-week intervals. Patients whose tumour stabilised or regressed after 4 vaccinations received 2 additional vaccinations at 6-week intervals. The vaccine was generally well tolerated. Among the 33 melanoma patients who were evaluable for tumour response, we observed 2 partial responses, 2 mixed responses and 1 stabilisation. Time to progression in these 5 patients varied from 4 to 29 months. In addition, a partial response lasting 10 months was observed in 1 of the 3 metastatic bladder cancer patients included. None of the tumour responses described above involved visceral metastases. Immunological responses to the vaccine will be reported separately.

[Secondary displacement of an Amplatz occluder for atrial septal defect. 2 case reports]

The authors report two cases of secondary displacement of an Amplatz occluder of isolated ostium secundum atrial septal defects. The displacement was observed at 1 month and the prosthesis removed at 3 months. To the best of the authors' knowledge, these are the first two reported cases of secondary displacement of this type of device. The main risk factor in the two cases was the absence of a subaortic septal remnant observed at surgical removal. This anatomical characteristic can be identified by transoesophageal echocardiography, but was poorly assessed by transthoracic echocardiography. Three-dimensional transoesophageal echocardiography should improve selection of atrial septal defects suitable for percutaneous treatment by better identification of their form and anatomical characteristics.

A monoclonal cytolytic T-lymphocyte response observed in a melanoma patient vaccinated with a tumor-specific antigenic peptide encoded by gene MAGE-3

Vaccination of melanoma patients with tumor-specific antigens recognized by cytolytic T lymphocytes (CTL) produces significant tumor regressions in a minority of patients. These regressions appear to occur in the absence of massive CTL responses. To detect low-level responses, we resorted to antigenic stimulation of blood lymphocyte cultures in limiting dilution conditions, followed by tetramer analysis, cloning of the tetramer-positive cells, and T-cell receptor (TCR) sequence analysis of the CTL clones that showed strict specificity for the tumor antigen. A monoclonal CTL response against a MAGE-3 antigen was observed in a melanoma patient, who showed partial rejection of a large metastasis after treatment with a vaccine containing only the tumor-specific antigenic peptide. Tetramer analysis after in vitro restimulation indicated that about 1/40,000 postimmunization CD8(+) blood lymphocytes were directed against the antigen. The same TCR was present in all of the positive microcultures. TCR evaluation carried out directly on blood lymphocytes by PCR amplification led to a similar frequency estimate after immunization, whereas the TCR was not found among 2.5 x 10(6) CD8(+) lymphocytes collected before immunization. Our results prove unambiguously that vaccines containing only a tumor-specific antigenic peptide can elicit a CTL response. Even though they provide no information about the effector mechanisms responsible for the observed reduction in tumor mass in this patient, they would suggest that low-level CTL responses can initiate tumor rejection.

[Finapres, efficient technique in the assessment of orthostatic hypotension, autonomic neuropathy, and vaso-vagal syncope]

Finapres is a device able to continuously and non invasively measure arterial blood pressure by photoplethysmography in the finger. It can be used in various dynamic tests which involve cardiocirculatory adjustments, as a passive posture test ("tilt test") or an active orthostatic test (from squatting to standing position in the so-called squatting test). It represents a valuable help in the diagnosis of orthostatic hypotension (of endogenous or iatrogenic origin), of autonomic neuropathy (secondary to diabetes mellitus or to a neurological disease) or of vasovagal syncope. All these conditions are characterized by a defect of arterial and venous vasoconstriction and by an insufficient reflex tachycardia because of autonomic dysfunction.

Biological and clinical developments in melanoma vaccines

The identification of antigens recognised on human tumours by autologous T-lymphocytes has opened the way for vaccination strategies involving defined tumour antigens. These vaccinations are therapeutic, i.e. they involve patients with detectable disease. Tumour regressions have been observed in a minority of melanoma patients in Phase I/II trials. Some of these regressions have been complete and long lasting. Improving the efficacy of therapeutic vaccines will critically depend on their capacity to trigger a robust immune response, on the development of appropriate methods to monitor these antitumour immune responses to vaccination and on a better understanding of the mechanisms used by tumours to escape immune attack. Finally, the initiation of large randomised Phase III trials will determine the impact of these vaccines on melanoma treatment.

Use of the Kleihauer test to detect fetal erythroblasts in the maternal circulation

Non-invasive prenatal diagnosis of aneuploidies on fetal nucleated erythrocytes present in the maternal circulation is hampered by the extremely small cell number of uncertain origin (70% of erythroblasts circulating during pregnancy have a maternal origin). Therefore, a method allowing selection of the fetal cells among the maternal cells is indispensable after the erythroblast enrichment step. In the present study, after an erythroblast enrichment step on a ficoll gradient followed by a positive immuno-magnetic selection with anti-CD71 or anti-GPA antibodies, a rapid, simple and direct chemical staining method adapted from the classical Kleihauer test was developed to select fetal cells. Precise differentiation between fetal and maternal erythroblasts is based on the constitutional difference between fetal and adult haemoglobin (Hb). The fetal cells appear with an intense pink cytoplasmic staining while maternal cells with adult haemoglobin are colourless. Preservation of the cytoplasmic integrity allows one to distinguish morphological characteristics and to visualize simultaneously nuclear hybridization signal by FISH (fluorescent in situ hybridization). This approach was tested by FISH analysis using dual-colour X- and Y-specific DNA probes on blood samples from 15 pregnant women, with the results being compared to cytogenetic or sonographic sex determination. For 12 pregnancies fetal sex was determined successfully (5 XY/7 XX), in two cases in situ hybridization failed, and in one case no fetal erythroblast was observed after the Kleihauer test. The selection method was applied to a pregnancy at risk for cystic fibrosis (CF). After a Kleihauer test, fetal erythroblasts were collected by microdissection, whole genomic DNA was amplified by primer extension pre-amplification (PEP) followed by a nested CF PCR. The fetal genotype was successfully characterized and confirmed by conventional prenatal diagnosis.

'Stealth' corona-core nanoparticles surface modified by polyethylene glycol (PEG): influences of the corona (PEG chain length and surface density) and of the core composition on phagocytic uptake and plasma protein adsorption

Nanoparticles possessing poly(ethylene glycol) (PEG) chains on their surface have been described as blood persistent drug delivery system with potential applications for intravenous drug administration. Considering the importance of protein interactions with injected colloidal dug carriers with regard to their in vivo fate, we analysed plasma protein adsorption onto biodegradable PEG-coated poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA) and poly(varepsilon-caprolactone) (PCL) nanoparticles employing two-dimensional gel electrophoresis (2-D PAGE). A series of corona/core nanoparticles of sizes 160-270 nm were prepared from diblock PEG-PLA, PEG-PLGA and PEG-PCL and from PEG-PLA:PLA blends. The PEG Mw was varied from 2000-20000 g/mole and the particles were prepared using different PEG contents. It was thus possible to study the influence of the PEG corona thickness and density, as well as the influence of the nature of the core (PLA, PLGA or PCL), on the competitive plasma protein adsorption, zeta potential and particle uptake by polymorphonuclear (PMN) cells. 2-D PAGE studies showed that plasma protein adsorption on PEG-coated PLA nanospheres strongly depends on the PEG molecular weight (Mw) (i.e. PEG chain length at the particle surface) as well as on the PEG content in the particles (i.e. PEG chain density at the surface of the particles). Whatever the thickness or the density of the corona, the qualitative composition of the plasma protein adsorption patterns was very similar, showing that adsorption was governed by interaction with a PLA surface protected more or less by PEG chains. The main spots on the gels were albumin, fibrinogen, IgG, Ig light chains, and the apolipoproteins apoA-I and apoE. For particles made of PEG-PLA45K with different PEG Mw, a maximal reduction in protein adsorption was found for a PEG Mw of 5000 g/mole. For nanospheres differing in their PEG content from 0.5 to 20 wt %, a PEG content between 2 and 5 wt % was determined as a threshold value for optimal protein resistance. When increasing the PEG content in the nanoparticles above 5 wt % no further reduction in protein adsorption was achieved. Phagocytosis by PMN studied using chemiluminescence and zeta potential data agreed well with these findings: the same PEG surface density threshold was found to ensure simultaneously efficient steric stabilization and to avoid the uptake by PMN cells. Supposing all the PEG chains migrate to the surface, this would correspond to a distance of about 1.5 nm between two terminally attached PEG chains in the covering 'brush'. Particles from PEG5K-PLA45K, PEG5K-PLGA45K and PEG5K-PCL45K copolymers enabled to study the influence of the core on plasma protein adsorption, all other parameters (corona thickness and density) being kept constant. Adsorption patterns were in good qualitative agreement with each other. Only a few protein species were exclusively present just on one type of nanoparticle. However, the extent of proteins adsorbed differed in a large extent from one particle to another. In vivo studies could help elucidating the role of the type and amount of proteins adsorbed on the fate of the nanoparticles after intraveinous administration, as a function of the nature of their core. These results could be useful in the design of long circulating intravenously injectable biodegradable drug carriers endowed with protein resistant properties and low phagocytic uptake.

Partial deletion of the AGXT gene (EX1_EX7del): A new genotype in hyperoxaluria type 1

Primary hyperoxaluria type 1 (PH1) is a rare autosomal (2q37.3) recessive metabolic disease caused by a deficiency of the hepatic peroxisomal enzyme alanine:glyoxylate amino transferase. Molecular heterogeneity is important in PH1 as most of the patients (if the parents are unrelated) are compound heterozygotes for rare mutations. We describe the first large deletion in the AGXT gene, removing exons 1 to 7 (EX1_EX7del) that was responsible for one case of severe PH1. This 10 kb deletion was identified by Southern blotting of genomic DNA digested by Xba I and hybridized with different exonic probes. Both parents (from Turkey) are first cousin and carry the deletion. It is of note that the presently reported patient did not exhibit any AGT catalytic activity and even so, he progressed towards end-stage renal disease only at 19 years old.

Cerebrospinal fluid protein concentrations in children: age-related values in patients without disorders of the central nervous system

BACKGROUND

The published reference values for cerebrospinal fluid (CSF) total protein concentrations in children suffer from two major drawbacks: (a) the age-related range often is too broad when applied to the steeply falling concentrations in early infancy; and (b) no values have been published for widely used dry chemistry methods.

METHODS

We conducted a 2-year retrospective survey of CSF results obtained in a children's hospital with a dry chemistry-based method set up on the Vitros 700 analyzer.

RESULTS

The data related to ambulatory children up to 16 years of age and term neonates with no clinical or biological signs of brain disease (n = 1074). Seven age groups with significantly different CSF protein values were identified, and their age-related percentiles (5th, 50th, and 95th) were determined. On the basis of the upper 95th percentile, from age 0 to 6 months the CSF protein concentrations fell rapidly from 1.08 to 0.40 g/L. A plateau (0.32 g/L) was reached from age 6 months to 10 years, followed by a slight increase (0.41 g/L) in the 10-16 years age range.

CONCLUSIONS

These results imply that CSF total protein concentrations in the pediatric setting, particularly in infants, must always be interpreted with regard to narrow age-related reference values to avoid false-positive results.

Antibodies to platelet factor 4-heparin after cardiopulmonary bypass in patients anticoagulated with unfractionated heparin or a low-molecular-weight heparin : clinical implications for heparin-induced thrombocytopenia

BACKGROUND

Cardiopulmonary bypass (CPB) induces platelet activation with release of platelet factor 4 (PF4), and patients are exposed to high doses of heparin (H). We investigated whether this contributes to the development of antibodies to H-PF4 and heparin-induced thrombocytopenia (HIT).

METHODS AND RESULTS

CPB was performed with unfractionated heparin (UFH) in 328 patients. After surgery, patients received UFH (calcium heparin, 200 IU. kg-1. d-1) (group 1, n=157) or low-molecular-weight heparin (LMWH, Dalteparin, 5000 IU once daily) (group 2, n=171). Eight days after surgery, antibodies to H-PF4 were present in 83 patients (25.3%), 46 in group 1 and 37 in group 2 (P=0.12). Most patients (61%) had IgG1 to H-PF4, but only 8 samples with antibodies induced platelet activation with positive results on serotonin release assay. HIT occurred in 6 patients in group 1, but no thrombocytopenia was observed in subjects receiving LMWH, although 2 had high levels of antibodies with positive serotonin release assay results. When antibodies to H-PF4 were present, mean platelet counts were lower only in patients with FcgammaRIIA R/R131 platelets.

CONCLUSIONS

These results provide evidence that the development of antibodies to H-PF4 after CPB performed with UFH is not influenced by the postoperative heparin treatment. The antibodies associated with high risk of HIT are mainly IgG1, which is present at high titers in the plasma of patients continuously treated with UFH.

[Immediate and mid-term results of surgery for aortic coarctation in children under 6 months of age]

The aim of this study was to assess the impact of medical and surgical advances on the results of surgery of coarctation of the aorta without major associated cardiac malformations in children aged under 6 months, operated by the surgical team of Tours over a period of 17 years. A retrospective analysis of patients' files allowed inclusion of 75 children: 34 in group I (1980-1988) and 41 in group II (1989-1996). The age at diagnosis, mode of presentation, clinical and echocardiographic parameters, initially and at surgery, were comparable in the two groups. In group II, the surgical procedure of choice changed to the Crafoord procedure (p = 0.0001), the peroperative haemodynamic complications were less common (p = 0.04), patients were operated sooner after diagnosis (p = 0.002) with a higher number of neonates (p = 0.04). There were two early deaths in group I and two late deaths in group II. Six children (8.2%) had recurrence of coarctation. This was more common in children operated before 1 month of age (p = 0.0001) and in cases of hypoplasia of the aortic arch (p < 0.01). The risk of recoarctation in neonates was lower in group II than in group I (p < 0.02). At medium term, the coarctation was considered well repaired in 93.7% and 92.6% of patients in group I and II respectively. However, hypertension on exercise was observed in 8 of the 19 children studied. Finally, secondary surgical or instrumental procedures were required in 9 children to treat associated cardiovascular abnormalities. The authors conclude that in recent years, aortic coarctation was repaired earlier, mainly by a modified Crafoord procedure, with fewer haemodynamic complications, without early mortality. The risk of recoarctation remains low but persistent in neonates. At medium term, hypertension on exercise is a common problem even in children with excellent repairs.

Detection of fluoxetine in brain, blood, liver and hair of rats using gas chromatography-mass spectrometry

This study reports the measurements of fluoxetine in discrete brain regions, blood, liver and hair of male rats injected with 10 mg/kg fluoxetine HCl for 15 consecutive days. Concentrations of the antidepressant were obtained by gas chromatography-mass spectrometry (GC-MS) methodology. In brain, fluoxetine levels were unevenly distributed, with the raphé nucleus containing the highest amounts relative to the hypothalamus or striatum. Fluoxetine was also measured in blood and liver roughly paralleling those ratios described in previous rodent studies. Of potential interest, fluoxetine was found to accumulate in rat hair after chronic treatment. Detection of fluoxetine in hair by GC-MS could be used as a marker for probative analyses.

Tumor regressions observed in patients with metastatic melanoma treated with an antigenic peptide encoded by gene MAGE-3 and presented by HLA-A1

Thirty-nine tumor-bearing patients with metastatic melanoma were treated with 3 subcutaneous injections of the MAGE-3.A1 peptide at monthly intervals. No significant toxicity was observed. Of the 25 patients who received the complete treatment, 7 displayed significant tumor regressions. All but one of these regressions involved cutaneous metastases. Three regressions were complete and 2 of these led to a disease-free state, which persisted for more than 2 years after the beginning of treatment. No evidence for a cytolytic T lymphocyte (CTL) response was found in the blood of the 4 patients who were analyzed, including 2 who displayed complete tumor regression. Our results suggest that injection of the MAGE-3.A1 peptide induced tumor regression in a significant number of the patients, even though no massive CTL response was produced.