In vitro characterization of biofilms formed by Kingella kingae.

The Gram-negative bacterium Kingella kingae is part of the normal oropharyngeal mucosal flora of children <4 years old. K. kingae can enter the submucosa and cause infections of the skeletal system in children, including septic arthritis and osteomyelitis. The organism is also associated with infective endocarditis in children and adults. Although biofilm formation has been coupled with pharyngeal colonization, osteoarticular infections, and infective endocarditis, no studies have investigated biofilm formation in K. kingae. In this study we measured biofilm formation by 79 K. kingae clinical isolates using a 96-well microtiter plate crystal violet binding assay. We found that 37 of 79 strains (47%) formed biofilms. All strains that formed biofilms produced corroding colonies on agar. Biofilm formation was inhibited by proteinase K and DNase I. DNase I also caused the detachment of pre-formed K. kingae biofilm colonies. A mutant strain carrying a deletion of the pilus gene cluster pilA1pilA2fimB did not produce corroding colonies on agar, autoaggregate in broth, or form biofilms. Biofilm forming strains have higher levels of pilA1 expression. The extracellular components of biofilms contained 490 µg cm-2 of protein, 0.68 µg cm-2 of DNA, and 0.4 µg cm-2 of total carbohydrates. We concluded that biofilm formation is common among K. kingae clinical isolates, and that biofilm formation is dependent on the production of proteinaceous pili and extracellular DNA. Biofilm development may have relevance to the colonization, transmission, and pathogenesis of this bacterium. Extracellular DNA production by K. kingae may facilitate horizontal gene transfer within the oral microbial community.

Adaptive immune response in osteoclastic bone resorption induced by orally administered Aggregatibacter actinomycetemcomitans in a rat model of periodontal disease.

There is mounting evidence that innate and adaptive immunity are critical for periodontal disease-mediated bone resorption. These studies examined the role of B and CD4 T cells in adaptive immunity of rats infected with Aggregatibacter actinomycetemcomitans (Aa). Sprague-Dawley male rats were fed Aa-containing mash or control-mash for 2 weeks. B and CD4 T cells were obtained from draining lymph nodes at 2, 4 and 12 weeks, postinoculation. Quantitative polymerase chain reaction-based messenger RNA expression was conducted for 89 cytokine family genes. Disease-relevance of the differentially expressed genes was assessed using a biological interaction pathway analysis software. B and CD4 T cells of Aa-infected rats increased and were activated, resulting in enhanced isotype-switched serum immunoglobulin G by 2 weeks postinoculation. Bone resorption was evident 12 weeks after Aa-feeding. In B cells, interleukin-2 (IL-2), macrophage-inhibiting factor, IL-19, IL-21, tumor necrosis factor (TNF), CD40 ligand (CD40L), CD70, bone morphogenetic protein 2 (BMP2), BMP3, and BMP10 were upregulated early; while IL-7, Fas ligand (FasL), small inducible cytokine subfamily E1, and growth differentiation factor 11 (GDF11; BMP11) were upregulated late (12 weeks). BMP10 was sustained throughout. In CD4 T cells, IL-10, IL-16, TNF, lymphotoxin-beta (LTbeta), APRIL, CD40L, FasL, RANKL and osteoprotegerin were upregulated early, whereas IL-1beta, IL-1RN, IL-1F8, IL-24, interferon-alpha1, GDF11 (BMP11), and GDF15 were upregulated late (12 weeks). Adaptive immunity appears crucial for bone resorption. Several of the deregulated genes are, for the first time, shown to be associated with bone resorption, and the results indicate that activated B cells produce BMP10. The study provides a rationale for a link between periodontal disease and other systemic diseases.

Ultrasound wall-sign in pulmonary echinococcosis (new application).

PURPOSE: We report our experience in diagnosing pulmonary cystic echinococcosis using an ultrasound sign related to the cystic wall. MATERIALS AND METHODS: 40 patients with 46 cysts, suspected of pulmonary echinococcosis, based on plain chest radiographs and clinical findings, were examined by ultrasound over a 9-year period (1996 - 2004), and followed up until discharge. We applied our long experience with echinococcal cysts utilising the wall sign (WS) to diagnose pulmonary hydatid disease. All cysts were subject to surgical removal, and postoperative histopathology was the gold standard. RESULTS: There were 34 (74 %) unilocular and 12 (26 %) multivesicular echinococcal cysts. In the univesicular cysts, the WS was found in 20 cases (66.7 %) while it was present in all multivesicular cysts (100 %). Following surgical removal, echinococcosis was confirmed by histopathology in all cases. CONCLUSION: We conclude that a double layered border in univesicular and double layered internal septum in multivesicular pulmonary echinococcal cysts is a reliable indicator of pulmonary echinococcosis, with a specificity of 66 % and 100 %, respectively.

Tetra-layered sign of adult intussusception (new ultrasound approach).

Two-dimensional ultrasound is the principle method for the detection of intussusception. The aim of this study was to establish a pathognominic ultrasound criterion for diagnosing intestinal intussusception to facilitate a proper clinical decision. We have developed a new approach to diagnosing colonic intussuception based on the hypothesis that ultrasound image of the invaginated segment should reveal four border layers. We called this sign tetra-layered sign (TLS). In a prospective manner, all adult patients diagnosed with intussusception using the TLS approach in the period from July 1990 and July 2005 were included in this study. All patients underwent explorative laparotomy, and our preoperative diagnoses were compared with the surgical outcome. Thirty patients were diagnosed with intestinal intussusception using the TLS ultrasound sign. Surgery confirmed the preoperative diagnosis in all cases. Conventional ultrasound is very reliable in diagnosing intestinal intussusception in adult patients when utilizing the simple ultrasound applicable TLS. This facilitates the decision-making, improves the clinical outcome and reduces the associated costs.

Giant hydronephrosis mimicking echinococcal cyst.

Cases of giant hydronephrosis are rare and usually contain no more than one to two liters of fluid in the collecting system. We report a remarkable case of giant hydronephrosis of > 17.5 Kg mimicking a huge echinococcal cyst.

[Negative D-dimers and peripheral pulmonary embolism]. / D-dimères négatifs et embolies pulmonaires périphériques.

The measurement of D-dimers is a recent addition to the diagnostic strategy of pulmonary embolism and has been shown to be a valuable tool with excellent sensitivity. However, there have been rare reports of patients with pulmonary embolism but negative D-dimer tests. The object of this study was to study patients with pulmonary embolism but negative D-dimers and to compare them with a population of patients with pulmonary embolism and raised D-dimers. One hundred and fifty consecutive patients admitted for pulmonary embolism were included in this study. All underwent measurement of D-dimers (normal <500 ng/ml) by an ELISA technique. The data of clinical examination and complementary investigations were analysed with respect to the D-dimers result. The sensitivity of raised D-dimers for pulmonary embolism was 96% (6 patients had results <500 ng/ml). The finding of chest pain was statistically greater in the group with negative D-dimers (p=0.01). In these cases, the emboli were all distal (p=0.0003), the average Miller index was significantly lower than in patients with high D-dimers (p=0.04) and the diagnostic value of ultrasound investigations (echocardiography, ultrasonography of lower limb veins) was less (p<0.0001). The authors conclude that measurement of D-dimers by the ELISA method may be non-diagnostic in distal pulmonary embolism and one explanation could be the less extensive thromboembolic process. In cases with negative D-dimers, a strong clinical suspicion of pulmonary embolism should lead to the request for further investigations.

Pseudotumor of the pituitary due to PROP-1 deletion.

Hypopituitarism associated with pituitary mass in childhood is most frequently the consequence of craniopharyngioma or Rathke's cleft cyst. We report a patient with an intrasellar pseudotumor associated with hypopituitarism, which led us to a misdiagnosis of intrasellar craniopharyngioma. After spontaneous involution of the mass, diagnosis was revised. DNA analysis showed a deletion in the Prophet of Pit-1 (PROP-1) gene, a pituitary transcription factor. It is important to recognize that a PROP-1 deletion can cause pituitary pseudotumor that can be mistaken for a craniopharyngioma or Rathke's pouch cyst.

Segmental portal hypertension due to a splenic Echinococcus cyst.

A 60-year-old Libyan woman developed perihilar splenic varices without other signs of portal hypertension. Plain abdominal X-ray examination showed two calcified structures in the left and right hypochondria. Ultrasound examination disclosed a 3-cm diameter, globally calcified hydatid cyst lodged in a critical location at the hilar region of the spleen. The cyst was compressing the hilar vessels which resulted in dilatation and varix formation. Another hydatid cyst measuring 5 cm in diameter, with extensive wall calcification was visualized in the right lobe of the liver. The splenic size was within normal limits. The liver revealed normal texture and size and the portal vein was of normal caliber. The patient underwent an uneventful splenectomy and was well at discharge.

Intracavitary cardiac hydatid cyst and the wall sign criteria.

Cardiac hydatid is rare at any age, accounting for less than 2% of all hydatid disease. The case is discussed of a 48-year-old female with a cardiac hydatid cyst attached intracavitary in the posterior wall of the right atrium. The Echinococcus cyst grows very slowly and, unless located in a critical anatomic site, it takes many years to evolve. Since the introduction of two-dimensional echocardiography, more cases are being diagnosed. The cyst was discovered incidentally by X-ray computed tomography and confirmed by trans-oesophageal echocardiography utilizing the wall-sign criteria developed by the authors. The cyst was removed surgically and the patient recovered by medical therapy.