Dissemination of extended-spectrum beta-lactamase-producing Enterobacteriaceae in pediatric intensive care units

To study the growing trend of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in pediatric intensive care units (PICUs), 88 nonrepetitive ESBL-producing isolates were prospectively collected and analyzed by molecular methods during a 16-month period. The emergence and dissemination of ESBL-producing Enterobacteriaceae in PICUs are the consequence of the clonal dissemination of a few epidemic strains along with the horizontal transmission of resistance gene-carrying plasmids among bacterial organisms.     

Clinical and radiographic spectrum of septic pulmonary embolism.

AIMS: To review the clinical presentation, radiographic findings, and outcome of therapy in children with septic pulmonary embolism. METHODS: Retrospective analysis of patients in a tertiary paediatric facility in northern Taiwan. RESULTS: Ten children were identified with septic pulmonary emboli in a four year retrospective chart review between 1998 and 2001. Seven were immunocompetent, two were premature infants, one had beta thalassemia major. Seven had community acquired staphylococcal infections and bacteraemia, of which six were methicillin resistant Staphylococus aureus (MRSA) isolates. Five had soft tissue infections, two bone infections, one suppurative otitis media, one catheter related infection, and one unknown foci of infection. Multiple and bilateral nodular pulmonary parenchymal lesions were common on plain chest radiographs, but chest computed tomography scans showed the additional findings of a "vessel sign" and central cavitations, confirming the existence of septic pulmonary embolism. CONCLUSIONS: Community acquired MRSA infections occurred in seven patients with septic pulmonary embolism but without predisposing high risk factors. Critically ill children with skin, soft tissue, or bone infections, when associated with septic pulmonary embolism in an area with a high rate of MRSA, should be empirically treated with glycopeptides (such as vancomycin or teicoplanin) before susceptibility results are known, in order to minimise morbidity and avoid mortality.     

NF-kappa B binding activity and cyclooxygenase-2 expression in persistent CCl(4)-treated rat liver injury

The involvement of NF-kappa B binding activity is known to be important in the mechanism of acute liver injury and in the induction of cyclooxygenase (COX-2). This study was performed to evaluate NF-kappa B binding activity and the expression of COX-2 in chronic liver injury induced by carbon tetrachloride (CCl(4)). Liver tissues from Sprague-Dawley rats were collected at 1, 3, 5, and 7th week after intraperitoneal injection of 0.1 mL of CCl(4)/100 g body weight twice a week. Reactive oxy-gen species (ROS) were measured in the postmitochondrial fraction by dichlorofluorescein formation with a fluorescent probe. An electrophoretic mobility shift assay was performed for NF-kappa B binding activity. Western blot was performed to measure the level of COX-1, COX-2, p65, p50, and I B proteins. ROS and NF-kappa B activity increased during the CCl4-induced chronic liver injury. The expression of nuclear p65 protein and p50 protein increased compared with that of the control, while the cytoplasmic I B protein decreased as the inflammation persisted. The expression of COX-2 in CCl(4)-treated rat liver increased compared with that of the control. It could be suggested that ROS produced by CCl(4) treatment increased NF-kappa B binding activity and thereby COX-2 expression, and these might be implicated in the progress of chronic liver damage.     

Genetic follow-up of male offspring born by ICSI,using a multiplex fluorescent PCR-based test for Yq deletions

De-novo deletions involving AZFa, b, c and d are one of the most common chromosomal aberrations in man resulting in defective spermatogenesis and male infertility. Currently, Yq deletion screening involves either single or multiplex PCR using Y-specific sequence tagged site markers and the subsequent analysis of the amplification products on ethidium bromide-stained agarose gels. To improve the practicality of routine and high throughput Yq testing, we have developed a more sensitive multiplex fluorescent (FL)-PCR screening system using genomic DNA extracted from cheek buccal cells as a readily available PCR template. For genetic follow-up studies of ICSI-conceived children, we also developed a DNA fingerprinting system based on the co-amplification of four highly polymorphic markers to validate family samples and detect any potential extraneous DNA contamination that could cause a misdiagnosis. Multiplex FL-PCR analysis of buccal cell DNA from two infertile men who conceived three sons by ICSI demonstrated that their Yq deletions were vertically transmitted. Fine mapping with additional Yq markers revealed identical deletion endpoints involving the loss of AZFdc sequences. This firstly indicates that the extent of the Yq deletion was unchanged on ICSI transmission and secondly supports the view that AZFdc deletions may arise by a common de-novo event. Analysis of paternal, maternal and sibling DNA fingerprints showed the co-inheritance of parental alleles by each male child and confirmed the expected relationship between each family member. The application of these new FL-PCR based screening tests in genetic follow-up studies will assist in confirming transmission of specific genetic defects to male offspring conceived by ICSI and provide a basis for genetic counselling and potential treatment options as these boys approach sexual maturity.     

Evaluation of a non-name-based HIV reporting system in San Francisco

OBJECTIVE: To develop and evaluate a non-name-based HIV reporting system. METHODS: A population-based study of the accuracy of a set of non-name codes and a prospective study of a laboratory-initiated HIV surveillance system conducted at a county hospital (site 1) and a health maintenance organization (site 2). Participants were persons reported with AIDS in San Francisco and patients with a positive test result for HIV antibody, p24 antigen, viral load, or a CD4 count at the study sites. RESULTS: Proper match rate was 95% for records with complete codes and records with at least 50% of the codes. Proper non-match rate was 99% for records with all code elements and 96% for records with at least 50% of the elements. Completeness of reporting was 89% (site 1) and 87% (site 2). Median number of days between test and receipt of test report at the health department was 9 days at site 1 and 7 days at site 2. During 1999, 78% of HIV-infected patients at site 1 and 87% at site 2 had an HIV-specific laboratory test. CONCLUSIONS: A non-name-based laboratory reporting system for HIV is feasible.     

Hand-held arthroscopic optical coherence tomography for in vivo high-resolution imaging of articular cartilage

We describe a novel hand-held polarization optical coherence tomographic (OCT) probe that can be inserted into mammalian joints to permit real-time cross-sectional imaging of articular cartilage. The transverse and axial resolutions of the arthroscopic OCT device are roughly 17 and 10 microm, respectively. Two-dimensional cross-sectional images of cartilage tissue with 500 x 1000 pixels covering an area 6 mm in length and 2.8 mm in depth can be acquired at nearly five frames/s and with over 100 dB of dynamic range. Design of an OCT as a hand-held device capable of providing such an optical biopsy of articular cartilage allows eventual in vivo detection of microstructural changes in articular cartilage that are not apparent using conventional arthroscopic cameras. The OCT probe can be easily incorporated in a conventional arthroscope for cartilage site guidance. The optical arrangement in the OCT scope minimizes specular back-reflection of the probe end face and absorption of body fluid in the path and ensures in-focus OCT imaging when it is in contact with the cartilage specimen to be examined. Successful application of in vivo arthroscopy to porcine articular cartilage demonstrates sufficient resolution and practicality for use in human joints.     

Preparation of epoxy-SiO2 hybrid sol-gel material for bone cement

An organic-inorganic hybrid material, epoxy-SiO(2), was prepared by incorporating epoxy structure units covalently into a SiO(2) glass network via the sol-gel approach. The precursor was obtained by the reaction of diglycidyl ether of bisphenol A (DGEBA) with 3-aminopropyl trimethoxysilane (APTS). The precursor was then hydrolyzed and co-condensated with tetraethyl orthosilicate (TEOS) in tetrahydrofuran (THF) at room temperature to yield epoxy-SiO(2) hybrid sol-gel material having a 50 wt % SiO(2) content. Thermal properties of the hybrid material were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The hybrid sol-gel material epoxy-SiO(2) was the solid, powder component of bone cement. The liquid component contains bis-phenol-A glycidyl methacrylate (Bis-GMA), triethyleneglycol dimethacrylate (TEGDMA), and methyl methacrylate (MMA) with 25, 55, and 20 vol %, respectively. We discuss the comparison between the new epoxy-SiO(2) bone cement and the commercial Simplex P bone cement. Mechanical properties such as Young's modulus, compressive strength, hardness, and impact strength of the new epoxy-SiO(2) bone cement exceeded those of Simplex P bone cement. The tensile and bending strengths of the new epoxy-SiO(2) bone cement were approximately the same as those of Simplex P bone cement. In order to evaluate the biocompatibility of the new bone cement, an MTT test and optical microscopy were conducted in cell culture. Results indicated that the new epoxy-SiO(2) bone cement exhibits very low cytotoxicity compared with Simplex P bone cement.