Evidence of niche partitioning among bacteria living on plastics, organic particles and surrounding seawaters

Plastic pollution is widespread in ocean ecosystems worldwide, but it is unknown if plastic offers a unique habitat for bacteria compared to communities in the water column and attached to naturally-occurring organic particles. The large set of samples taken during the Tara-Mediterranean expedition revealed for the first time a clear niche partitioning between free-living (FL), organic particle-attached (PA) and the recently introduced plastic marine debris (PMD). Bacterial counts in PMD presented higher cell enrichment factors than generally observed for PA fraction, when compared to FL bacteria in the surrounding waters. Taxonomic diversity was also higher in the PMD communities, where higher evenness indicated a favorable environment for a very large number of species. Cyanobacteria were particularly overrepresented in PMD, together with essential functions for biofilm formation and maturation. The community distinction between the three habitats was consistent across the large-scale sampling in the Western Mediterranean basin. 'Plastic specific bacteria' recovered only on the PMD represented half of the OTUs, thus forming a distinct habitat that should be further considered for understanding microbial biodiversity in changing marine ecosystems.

Short-term associations between fine and coarse particles and hospital admissions for cardiorespiratory diseases in six French cities

OBJECTIVES

Little is known about the potential health effects of the coarse fraction of ambient particles. The aim of this study is to estimate the links between fine (PM(2.5)) and coarse particle (PM(2.5-10)) levels and cardiorespiratory hospitalisations in six French cities during 2000-2003.

METHODS

Data on the daily numbers of hospitalisations for respiratory, cardiovascular, cardiac and ischaemic heart diseases were collected. Associations between exposure indicators and hospitalisations were estimated in each city using a Poisson regression model, controlling for confounding factors (seasons, days of the week, holidays, influenza epidemics, pollen counts, temperature) and temporal trends. City-specific findings were combined to obtain excess relative risks (ERRs) associated with a 10 mug/m(3) increase in PM(2.5) and PM(2.5-10 )levels.

RESULTS

We found positive associations between indicators of particulate pollution and hospitalisations for respiratory infection, with an ERR of 4.4% (95% CI 0.9 to 8.0) for PM(2.5-10 )and 2.5% (95% CI 0.1 to 4.8) for PM(2.5). Concerning respiratory diseases, no association was observed with PM(2.5), whereas positive trends were found with PM(2.5-10), with a significant association for the 0-14-year-old age group (ERR 6.2%, 95% CI 0.4 to 12.3). Concerning cardiovascular diseases, positive associations were observed between PM(2.5) levels and each indicator, although some did not reach significance; trends with PM(2.5-10 )were weaker and non-significant except for ischaemic heart disease in the elderly (ERR 6.4%, 95% CI 1.6 to 11.4).

CONCLUSIONS

In accordance with other studies, our results indicate that the coarse fraction may have a stronger effect than the fine fraction on some morbidity endpoints, especially respiratory diseases.

Amphiphilic diblock copolymers with adhesive properties: I. Structure and swelling with water

We study asymmetric block copolymers with the simple diblock AB architecture, in the case where the longer block A is both hydrophobic and "soft", whereas the shorter block B is hydrophilic and "hard". Materials with such a particular combination of physico-chemical and mechanical properties have distinctive advantages, in particular for designing water-compatible adhesive materials. The phase diagram is established, combining NMR and SAXS characterisations of the materials. The swelling with water is monitored through gravimetry and "time-resolved" SAXS. Indications of maintained adhesive properties in a wet environment are given.

Estimation de la mortalité attribuable aux particules (PM10) dans les 9 villes françaises participant au programme européen Apheis

The relationship between air pollution and mortality is now admissible with a sufficiently high level of causality proven. This link allows for health impact assessment to be carried out with a significant degree of accuracy, such as the case for the results which are presented here from the nine French cities involved in the Apheis programme. This health impact assessment is based on the methodology developed by the World Health Organization. The number of avoidable deaths is contained between categories ranging from 2.0 to 4.3, 4.0 to 8.9, and from 15.0 to 31.5 per 100,000 inhabitants according to very short term effects, short term effects and long term effects, respectively. There are two scenarios which can be envisioned for the reduction of fine particles levels which are capable of obtaining similar results for both very short term and short term effects. The first involves diminishing the daily concentrations which are above 20 microg/m3 until they reach this value, and the second entails systematically decreasing the daily levels by 5 microg/m3. The first strategy of reducing values to stabilize at 20 microg/m3 has been shown to be the one most favourable and promising for the long term effects. This strategy therefore confirms the reliability and strength of the recommendation formulated at the national level.

Force response of a viscous liquid in a probe-tack geometry: fingering versus cavitation

We perform traction experiments on viscous liquids highly confined between parallel plates, a geometry known as the probe-tack test in the adhesion community. Direct observation during the experiment coupled to force measurement shows the existence of several mechanisms for releasing the stress: while fingering is favored for low traction velocities, low confinement and low viscosity, nucleation of bubbles occurs in the opposite conditions. It is possible to quantitatively predict the transition between the two regimes and, in many respects, describe the shape of the force response. Using a model for purely viscous fluids, we also present a phase diagram for the different force peak regimes that remarkably accounts for the data. Our results show that conspicuous features of the traction curve commonly thought to be characteristic of soft viscoelastic solids like adhesives are already encountered in liquid materials.

Immunogenicity and safety of a new liquid hexavalent combined vaccine compared with separate administration of reference licensed vaccines in infants

OBJECTIVE

The immunogenicity and safety of a new liquid hexavalent vaccine (diphtheria-tetanus-acellular pertussis-inactivated polio vaccine-hepatitis B-polyribosyl ribitol phosphate conjugated to tetanus protein; Hexavac; Aventis Pasteur MSD, Lyon, France) are compared with those of reference vaccines [diphtheria-tetanus-acellular pertussis-inactivated polio vaccine reconstituting lyophilized purified Haemophilus influenzae polysaccharide conjugated to tetanus protein vaccine (Pentavac; Aventis Pasteur MSD) and hepatitis B vaccine (H-B-Vax II; Aventis Pasteur MSD)] injected separately at the same visit in a prospective multicenter, comparative, open label trial.

METHODS

Infants were randomized to receive Hexavac (n = 423) or Pentavac and H-B-Vax II (n = 425) as a primary immunization series at 2, 4 and 6 months of age. Seroprotection and seroconversion rates against all antigens at 1 month after the primary series were compared between the two vaccine groups with 95% confidence intervals (CI0.95) and were considered clinically equivalent (not inferior) when the upper limit of the 95% confidence interval on the difference (reference, hexavalent) was below predefined differences.

RESULTS

Hexavac met and surpassed the pre-defined criteria for clinical equivalence to Pentavac and H-B-Vax II given concomitantly. It elicited similar seroprotection and seroconversion rates against all antigens. Seroprotection and seroconversion rates obtained 1 month after the third dose of Hexavac were >90% for all antigens. The postimmunization antibody geometric mean titers (GMT) for hepatitis B and purified Haemophilus influenzae polysaccharide were about 2-fold higher in infants who received the reference vaccines than in infants who had received Hexavac. GMTs for poliovirus antibodies tended to be enhanced in infants vaccinated with Hexavac. GMTs for all other antigens were very similar among both groups. Hexavac was generally well-tolerated. At least one local reaction was reported in 20.3% of Hexavac injections compared with 15.8% at the Pentavac injections site and 3.8% at the H-B-Vax II injections site. These reactions were generally mild and transient. At least one systemic adverse event was reported in 45.7% of Hexavac injections compared with 42.2% of Pentavac and H-B-Vax II injections (mild fever, irritability and drowsiness were most frequently reported). The frequency of adverse events was not significantly different between groups. No vaccine-related serious adverse event occurred during the study.

CONCLUSION

This liquid hexavalent vaccine was generally well-tolerated and provided immune responses adequate to be protective against six infectious diseases with a single injection, given at 2, 4 and 6 months of age.

The management of extreme hypernatraemia secondary to salt poisoning in an infant

We describe a five-week-old boy who had seizures and extreme hypernatraemia secondary to ingesting an improper home-made formula. Initial sodium concentration was 211 mmol.l-1. Other clinical and biological features were moderate dehydration and renal insufficiency with generous urine output and high urinary sodium concentration. Fluid therapy with hypotonic dextrose solution corrected the volume deficit in 48 h and progressively decreased the serum sodium concentration. During ICU stay the patient developed recurrent episodes of seizures and pulmonary oedema requiring mechanical ventilation for five days. Recovery was complete with no abnormal sequelae after a ten-month follow-up. Salt poisoning is in unusual cause of extreme hypernatraemia. It can be safely managed with fluid therapy alone if urine output is preserved, with progressive decrease of serum sodium as target. If this condition is recognized, outcome should be favourable.

Safety and immunogenicity of three doses of a Neisseria meningitidis A + C diphtheria conjugate vaccine in infants from Niger

BACKGROUND

High rates of endemic disease and recurrent epidemics of serogroup A and C meningococcal meningitis continue to occur in sub-Saharan Africa. A meningococcal A + C polysaccharide diphtheria-toxoid-conjugated vaccine may address this issue.

METHODS

In Niger three doses of a bivalent meningococcal A + C diphtheria-toxoid-conjugated vaccine (MenD), containing 1, 4 or 16 microg of each polysaccharide per dose, administered at 6, 10 and 14 weeks of age, were compared with Haemophilus influenzae type b-tetanus toxoid-conjugated (PRP-T) vaccine given with the same schedule or with a meningococcal A + C polysaccharide vaccine (MenPS) given at 10 and 14 weeks of age. One blood sample was taken at the time of enrollment (6 weeks of age) and another was taken 4 weeks after the primary series.

RESULTS

All doses of MenD were well-tolerated. After the primary series a higher proportion of infants had detectable serum bactericidal activity against serogroup A for each dose of MenD (from 94% to 100%) than for MenPS (31%) or H. influenzae type b-tetanus toxoid-conjugated vaccine (18.9%); P < or = 0.05. Significant differences were also observed for serogroup C MenD 4 microg or MenD 16 microg (100%) vs. MenPS (69.7%) or Haemophilus influenzae type b-tetanus toxoid-conjugated vaccine (24.3%); P < or = 0.05. When MenPS vaccine was given to 11-month-old children, the immune response measured by both enzyme-linked immunosorbent assay and serum bactericidal assay was greater in those previously immunized with MenD than in those immunized with MenPS vaccine.

CONCLUSION

MenD was safe among infants in Niger, and immunization led to significantly greater functional antibody activity than with MenPS. The 4-microg dose of MenD for both the A and C serogroups has been selected for further studies.

Switchable tackiness and wettability of a liquid crystalline polymer

The spreading velocity of liquids on the surface of a liquid crystalline polymer can be tremendously affected by a slight temperature change. Indeed, a bulk transition between a highly ordered smectic and an isotropic phase induces a sharp change from a rigid to a soft behavior, with consequent effects on the tack properties of the liquid crystalline polymer and on the dewetting dynamics of a liquid on its surface.

New acellular pertussis-containing paediatric combined vaccines

Combined pediatric vaccines have the advantages of conferring protection against multiple common infectious diseases with a reduced number of injections. Their use should lead to better compliance to recommended vaccination schedules. Diphtheria (D), tetanus (T) and whole-cell pertussis vaccine (P) have been successfully combined, with or without inactivated poliovirus vaccine (IPV) in the same syringe for many years. Recently developed acellular pertussis (aP) Haemophilus influenzae type B (Hib), inactivated poliomyelitis virus and hepatitis B vaccines are ideal candidates for inclusion in current combined vaccines. Nevertheless, the development of new combinations has to face preclinical and clinical issues: the appropriate formulation of the new antigen(s) and other vaccine components needs to be determined to ensure compatibility and guard against potential additive or unexpected adverse reactions; potential immunological interference between antigens and the negative impact of other vaccine components on immunogenicity may occur, and these have to be examined also. Whole-cell pertussis vaccines are highly protective against whooping cough, but the severe adverse reactions that these vaccines sometimes produce have led to hesitation over their use, including the decision of some countries to stop pertussis immunization. To increase the acceptability of pertussis vaccination, Pasteur Mérieux Connaught has developed a combined D, T and a two-component acellular pertussis vaccine (DTaP), composed of purified pertussis toxoid (PT) and filamentous haemagglutinin (FHA), which has been shown to be effective in an efficacy trial conducted in Senegal. Acellular DTaP vaccines are immunogenic and have a better safety profile than DTP vaccines, when given either for the primary series, for the booster vaccination or for both. In order to meet worldwide demands, the combined DTaP-IPV or DTP-IPV has been developed for countries where IPV is recommended. Following the encouragement of the WHO, an H. influenzae type B tetanus-conjugated (Act-HIB) vaccine, has been combined in a full liquid formulation with the whole-cell DTP. This vaccine showed a good safety and immunogenicity profile in infants and in toddlers. A combined DTaP-IPV-PRP-T vaccine (where the Act-HIB vaccine is reconstituted by the full-liquid DTaP-IPV) also has been successfully developed both for the primary series and for booster vaccination; although, a reduced immunogenicity against PRP observed after the primary series, this did not affect vaccine priming. Hepatitis B immunization campaigns targeting high-risk groups have failed to control the disease in areas of low endemicity. In 1992, the WHO recommended that hepatitis B vaccination should be integrated into the EPI in all countries by 1997-1999. For that purpose, hepatitis B vaccine is currently evaluated in pediatric combined vaccines. Developing new combination vaccines is a difficult but essential process for maintaining high immunization rates worldwide against infectious diseases, provided that the costs are acceptable. New combined vaccines including pneumococcal and meningococcal component are under wide-scale development.

[Severe potassium dichromate poisoning after accidental nasal introduction]

BACKGROUND

Nasal foreign body (NFB) is a common situation in pediatrics. Poisoning is a rare complication of NFB insertion. We report a case of acute potassium dichromate poisoning secondary to NFB insertion.

CASE REPORT

Six days after insertion of a NFB, progressive occurrence of diarrhea, vomiting, nasal obstruction, acute renal failure, pancreatitis, hepatitis and drowsiness justified hospitalization of a 3-year-old girl in the pediatric intensive care unit. Acute potassium dichromate poisoning was confirmed by high plasma chromium level and by the spectrophotometric analysis of the crystal. Recovery was satisfactory with supportive treatment. An official survey allowed to discover that the crystal was freely sold and that its toxicity was unknown by dealers, while no information was given to the customers.

CONCLUSION

Transmucosal absorption of toxics is an unusual severe potential hazard that should be evoked to allow a rapid management. After the discovery and withdrawal of a NFB, occurrence of systemic symptoms, even trivial, must make one suspect a poisoning. In this circumstance, analysis of the foreign body should be done, associated with toxicologic dosages. This case report illustrates that potassium dichromate poisoning is a severe medical condition and that its clinical presentation assume a large widespread of symptoms due to multiple organ involvement.

[Incidence of inflammatory bowel diseases in the department of Puy-de-Dôme in 1993 and 1994. EPIMICI. Epidémiologie des Maladies Inflammatoires Cryptogenetiques de l'Intestin group]

The aim of this prospective epidemiological study was to investigate the incidence of Inflammatory Bowel Disease in the Puy-de-Dôme county using the same methodology as EPIMAD's registry.

METHODS

From 01/01/93 to 31/12/94, each gastroenterologist (n = 22) collected patients consulting for the first time with clinical symptoms compatible with inflammatory bowel disease. Data were reported on a questionnaire by an interviewer practitioner. The final diagnosis of Crohn's disease and ulcerative colitis was made in a blind manner by two expert gastroenterologists and recorded according to the Calkin's criteria as definite, probable, or possible diagnosis, or unclassifiable chronic colitis or acute colitis.

RESULTS

167 new cases were identified: 112 (67.1%) inflammatory bowel disease for the combined group of definite and probable cases with 79 Crohn's disease (70.5%), 29 ulcerative colitis (25.9%) of which 11 ulcerative proctitis (37.9%), 4 unclassifiable chronic colitis (3.6%) and 55 acute colitis (32.9%). The crude and age-adjusted incidence (per 10(5)/year) was respectively 6.6 and 5.7 for Crohn's disease and 2.4 and 1.9 for ulcerative colitis. The highest age-specific incidence rate for Crohn's disease was between 40-49 years (14.1) and for ulcerative colitis between 80-89 years (6.8). The female/male ratio was 0.8 for Crohn's disease and 1.1 for ulcerative colitis. The median age at the time of diagnosis was 42.6 years for Crohn's disease and 35.3 years for ulcerative colitis.

CONCLUSIONS

These preliminary findings revealed a high incidence of Crohn's disease and low of ulcerative colitis in this county. However, these results must be managed carefully because these data were recorded only on two years and the inflammatory bowel disease classified possible and acute colitis require a follow-up.

[A rare form of benign tumor of the liver possibly related to the use of oral contraceptives: focal pediculated nodular hyperplasia]

Following a recent case, the authors review the literature of hepatic nodular hyperplasia. The incidence of this condition increases regularly with the consumption of oestrogens. They attempt to define the methods of detection for patients at highest risk. Without exaggerating the incidence of this complication of oral contraceptives, the authors believe that it will become increasingly more common than the vascular complications which, although frequently discussed, are relatively rare.

[Hypoglycemia-inducing islet cell tumors. Measurement of blood glucose and insulin levels during operation. Results in seven cases (author's transl)]

The identification of hypoglycemic langerhans tumours by the surgeon, being sometimes difficult, per-operative quantity determinations of the glycemia and insulinemia levels help to ensure that all the insulino-secretory tissue has been removed. The technical protocol described includes an excess of glucids. In the 5 cases of adenomas, between 30 and 60 minutes after exeresis, a distinct increase in glycemia was noted (on average 1,25 g/l) in comparison to the initial level; this increase was not however significant in the 2 observations of adenomatous hyperplasia. Following the removal of the lesion, the fall in insulinemia is also more noticeable in adenomas (reaching 75,8 per cent of the initial level) than in adenomatous hyperplasia. Nonetheless, the fall in the latter is still considerable (42,4 per cent). This examination would be the best test, excvept that the results are known only after the operation. The 7 patients operated on recovered after 2 enucleo-excisions, and 5 isthmo-corporal-caudal splenopancreatectomies, the average post-operative period reaching 4 years.

Computed tomography in olfactory neuroblastoma: one case of esthesioneuroepithelioma and four cases of esthesioneuroblastoma

Five cases of histologically confirmed olfactory neuroblastoma (esthesioneuroblastomas) have been studied by computed tomography (CT). Both the clinical symptoms (in particular, unilateral nasal obstruction and recurring epistaxis) and radiological findings (opacity of the paranasal sinuses) are nonspecific. Computed tomography shows a contrast enhancing mass-lesion and is more useful than conventional tomography in estimating its extension and the associated bone destruction, secondary reaction of sinusitis, and tumoral calcification. In the two cases in which the tumor was associated with exophthalmos, CT demonstrated that the muscular cone acts as a barrier preventing tumoral invasion. In cases wtih intracranial involvement, it appears that the attenuation values can be useful for differentiating between invasion by contiguity (two cases) versus metastasis (one case). Computed tomography is valuable in the follow-up and during and after radiotherapy of the tumor.

[Thymoma and lupus disease (apropos of 2 cases]

Two new cases of association between a thymoma and a lupus illness are reported. The first was a women aged 42 years in whom were discovered simultaneously systemic lupus erythematosus (SLE) and a slowly invading thymoma, the histology of which was characterized by the predominance of epithelial cells; excision of this tumour did not appear to affect the evolution of the SLE. In the second case, a patient aged 60 years suffered from SLE ten months after the removal of a benign thymoma in which there was a predominance of lymphocytes. The SLE in this patient was easily controlled for more than a year by small doses of corticoids, but resulted in death after three years when anuria was associated with meningeal signs after the cessation of corticotherapy. The comparision of the data from these cases with those from eleven other cases in which there was association between a thymoma and SLE, brought to light several interesting facts. It is rare that SLE clearly precedes the discovery of the thymoma; it usually occurs afterwards or the two are discovered almost simultaneously. Collagenosis is of importance only when it coexists with a thymoma : starting later much more often than is usual in cases of SLE. The tumours were, in all but two cases, benign thymomas of different histological types, and their removal did not apparently influence the evolution of the SLE.