[Neonatal cellulitis caused by group B Streptococcus]. / Cellulite néonatale à streptocoque du groupe B.

Dermohypodermitis (cellulitis) in newborn infants and in infants aged up to 3 months is uncommon and often not typical. Because group B Streptococcus is known to induce rapid life-threatening complications, early diagnosis leading to emergency treatment is of utmost importance. We report on the case of a 14-day-old girl, initially admitted for viral bronchiolitis with suspected bacterial pulmonary infection, in the absence of any cutaneous injury. The disease actually was cellulitis of the face, caused by group B Streptococcus. The baby presented with a severe septic clinical condition. Early treatment with antibiotics (intravenous amoxicillin for 10 days) allowed a favorable course, with rapid control of the sepsis and regression of the submandibular tumefaction.

Degradation of hydroxylapatite, fluorapatite, and fluorhydroxyapatite coatings of dental implants in dogs.

Calcium phosphate coatings on dental implants enhance integration of the material. Resorption of the ceramic coatings has raised some concern about the behavior of the bone-implant interfaces after the coating disappearance. Substitution of the OH- ions by fluoride in the hydroxylapatite (HA) lattice makes the calcium phosphate more stable. We investigated the degradation rate of dental implants with 50- and 100-microm coatings of HA, fluorapatite (FA), or fluorhydroxylapatite (FHA). The implants were inserted in dog jaws and retrieved for histological analysis after 3, 6, and 12 months. The thickness of the calcium phosphate coatings was evaluated using an image analysis device. A relative resorption index and its standard deviation were studied. HA and FA coatings (even at 100-microm thickness) were almost totally degraded within the implantation period. In contrast, the FHA coatings did not show significant degradation during the same period. The standard deviation showed that the resorption process for FHA with thicknesses of 50 or 100 microm was the same. Such a difference was not observed between the 50- and 100-microm thick coatings of FA and HA. In conclusion, the FHA coatings showed good integration in the bone tissue and lasted much longer than classic calcium phosphate coatings.

Pulmonary haemodynamics after surfactant replacement in severe neonatal respiratory distress syndrome.

Aortopulmonary pressure difference and pulmonary blood flow velocity were studied during the first 48 hours of life in 12 premature neonates with severe respiratory distress syndrome (RDS), treated by natural surfactant, and in 25 premature neonates with mild RDS. A non-invasive Doppler ultrasound method was used to estimate aortopulmonary pressure difference and pulmonary blood flow velocity from the left pulmonary artery. Aortopulmonary pressure difference was significantly lower at 6 hours of age in the infants with severe RDS and was not increased one hour after surfactant therapy. Aortopulmonary gradient started to rise at 24 hours of age and was equal to that of neonates with mild RDS at 48 hours. Pulmonary blood flow velocity was significantly lower, initially in the severe RDS group, and was not increased one hour after surfactant therapy. Left pulmonary artery flow velocity began to rise after 24 hours and reached the values of the mild RDS group at 48 hours. These data indicate that aortopulmonary pressure difference and pulmonary blood flow are low in the acute phase of RDS and that surfactant treatment does not seem to affect these values.

[Cardiac tamponade secondary to umbilical venous catheterization accident in a premature infant]. / Tamponnade cardique secondaire à un accident de cathétérisme veineux ombilical chez un prématuré.

BACKGROUND: Cardiac tamponade is a rare and sometimes severe complication of umbilical venous catheterization. CASE REPORT: A premature newborn (gestational age: 30 weeks, birth weight: 1,215 g) required assisted ventilation and umbilical venous catheterization for respiratory distress. Subsequent chest X-ray showed the ascending tip of the catheter lying in the left atrium, inside the auricle. At the age of 16 hours, the infant presented with episodes of bradycardia. Despite a second endotracheal intubation, a sudden vascular collapse necessitated cardiac massage plus sodium bicarbonate and epinephrine. An ultrasound examination was performed because of the persistence of the vascular collapse; it showed a clear echo-free space between the epicardium and pericardium, suggesting pericardial effusion. The patient responded dramatically to pericardial aspiration, providing hemorrhagic fluid containing 20 g per liter glucose. DISCUSSION: Cardiac tamponade probably occurred in this patient as a result of perforation of the atrial wall. Ultrasonography showed no local thrombus, but confirmed the cardiac compression by pericardial fluid and the localization of the tip of catheter in contact with the atrial wall. This case led us to review the mechanical complications of umbilical venous and/or percutaneous catheterization and the rules for their use. CONCLUSION: This complication must be suspected in all patients having a central venous catheter that present with vascular collapse.

[Polynuclear neutrophils and periodontal diseases]. / Les polynucléaires neutrophiles et les maladies parodontales.

Periodontal diseases are bacteria associated diseases. The host response to these bacteria is critical. Non specific defense mechanisms are mainly mediated by the polymorphonuclear neutrophil which out numbers the others crevicular leucocytes. This paper reviews the beneficial and possible detrimental aspect of the neutrophil functions.

Physicochemical characterization of deposits associated with HA ceramics implanted in nonosseous sites.

Pellets of well-characterized microporous hydroxyapatite (HA) ceramic were implanted in hamsters in two nonosseous sites: (1) in the fatty tissue of the gingival crease, far from bony tissue and (2) in intraperitoneal sites. The implants in site 1 were placed directly in contact with tissues, cells, and extracellular fluids while the implants in site 2 were placed in special chambers made of plexiglass cylinders covered in both ends with millipore filters, preventing contact with tissues and cells, but not with extracellular fluids. The hamsters were sacrificed and the implants recovered after 8, 16, 30, 150, and 365 days. The pellets were characterized using x-ray diffraction, infrared absorption, thermogravimetry, scanning and transmission electron microscopy, and calcium and phosphate analyses before and after implantation. Physicochemical analyses of HA ceramic implants before and after implantation demonstrated the formation of new material which was significantly different from the HA ceramic in terms of the following: (a) morphology (size of shape) of crystals; (b) intimate association of the inorganic phase of the new material with an organic phase similar to inorganic/organic association in bone; (c) the inorganic phase of the new material is a CO3-apatite, similar to that of bone, while the HA in ceramic is CO3-free; (d) electron diffraction of apatite of new material is similar to that of bone apatite. This study also demonstrated that the new material associated with the HA ceramics implanted in two different nonosseous sites were identical in spite of the differences in their microenvironment (cellular and acellular).

[Ultrastructural study of bone formation after bioapatite implantation in man]. / Etude ultrastructurale de l'induction osseuse après implantation de bioapatites chez l'homme.

Synthetic hydroxyapatite crystals (Bioapatite) were implanted in a vestibular longitudinal groove made in the alveolar bone, the periodontal membrane and the superficial root dentine of 2 human canines in the absence of periodontal disease. The healing process was followed in scanning as well as in transmission electron microscopy. At 6 months, the aggregate of synthetic hydroxyapatite crystals was surrounded by a fibrous connective tissue, devoid of inflammatory cells. Small apatite crystals, similar to the neighbouring bone crystals, were deposited between the Bioapatite crystals in the central area of the aggregates. These small crystals filled the intercrystalline spaces from the center to the periphery. The mineralization extended then directly in the collagen matrix (osteoid tissue) surrounding the synthetic apatite aggregates. Bone tissue was thus formed around the apatite implants. At 1 year, the thickness of the bone tissue formed around the synthetic hydroxyapatite aggregates was increased. It consisted of bone with a well-oriented collagen matrix, with osteocyte lacunae, osteocytes and interosteocytic canaliculi, with normal ultrastructure.

[Histological study of the biocompatibility of hydroxyapatite crystals in periodontal surgery]. / Etude histologique de la biocompatibilité des cristaux d'hydroxyapatite en chirurgie parodontale.

The purpose of this investigation was to analyse, after 6 years of clinical trials, the findings obtained from biopsies of infrabony defects in man treated by grafts of hydroxyapatite. Filled extraction sockets in miniature swine treated in a similar manner with apatite were also studied. Light microscope analysis showed bone neoformation around and in the neighbourhood of grafted apatite fragments with the presence of osteocytes, osteoblasts and a normal peripheral connective tissue without inflammatory reaction. These results demonstrate the biocompatibility of the implanted apatites accompanied by a normal fibrogenesis and a seeming osteogenesis.

Influence of 3-methoxy 5,7,3',4'-tetrahydroxyflavan (ME) on experimental periodontitis in the golden hamster.

Experimental periodontal disease was induced in golden hamsters by feeding the animals with a Keyes 2 000 diet. The aim of the present study was to investigate the effect of 3-methoxy 5,7,3',4'-tetrahydroxyflavan (ME), a flavanoid derivative, on periodontally induced changes by this diet which was fed ad libitum to half of the animals for 2 months prior to the start of drug therapy. The animals were then divided into 4 groups: A) control animals on normal diet; B) ME-treated (200 mg/kg 3 times a week i.p.) animals on normal diet; C) animals on Keyes 2 000 diet; D) ME-treated (200 mg/kg 3 times a week i.p.) animals on Keyes 2 000 diet. ME inhibited the diminution of bone volume as measured morphometrically. The growth of dental plaque as evaluated by a sensitive index (PII) appeared to be retarded by ME. The average PII in the ME-treated animals reached after 2 months of diet remained unchanged during the drug therapy period (4 months); whereas it was significantly increased in the group C hamsters. The biochemical data further suggest that the resorption process of the alveolar bone was decreased by ME.