Risk-prediction tool for identifying hospitalized children with a predisposition for development of venous thromboembolism: Peds-Clot clinical Decision Rule

BACKGROUND

The prevalence of VTE is increasing in tertiary pediatric hospitals. Identification of high-risk populations using uniform criteria is required to develop evidence-based VTE prevention guidelines.

OBJECTIVE

To develop a VTE risk prediction rule, the Peds-Clot clinical Decision Rule (PCDR), to identify high-risk children who were at increased risk of developing VTE.

METHODS

This retrospective case-control study developed the PCDR using a derivation cohort (173 cases, 346 controls) and validated it on a separate validation cohort (100 cases, 100 controls). A uniform data collection strategy was applied to derive both the samples. Conditional logistic regression analyses were used to develop a risk-prediction model. Each significant predictor was assigned a score based on its beta coefficient and the PCDR was developed. ROC curves were derived to test the performance of the PCDR.

RESULTS

Characteristics of derivation and validation cohorts were comparable. Six risk factors (positive blood stream infection, central venous catheter, direct admission to ICU/NICU, hospitalization for ≥ 7 days, immobilization for > 72 h, and use of birth control pills) formed the final risk prediction model (risk score range, 0.5-9.5). A risk score of 3 or more identified high-risk children at a sensitivity of 70% and specificity of 80% and AUC of 0.852 (95% confidence interval, 0.814-0.890). The application of a risk score to the validation sample showed sensitivity 57% and specificity 88% and an AUC of 0.875 (95% confidence interval, 0.82-0.924).

CONCLUSION

Incorporation of the PCDR in routine clinical care can be an attractive strategy to identify high-risk hospitalized children with a predisposition for VTE. The clinical utility of the PCDR needs validation in prospective studies.

Poor compliance with child safety restraint use while travelling

Road traffic accidents are a leading cause of death of children. It is the law that all children should be appropriately secured when traveling in vehicles. The aim of this study was to evaluate parental conformity with these regulations and to test if advice given at a Paediatric outpatient clinic could improve compliance. Two groups were assigned, an intervention group (parents given an information leaflet and a clear explanation about appropriate restraints for their children) and a non-intervention group (received no information). They were contacted again after 2 months and asked regarding compliance. A total of 394 children from 186 families were initially given the questionnaire. Nearly one third of children (29.2%) were not using any restraint while travelling rising to 35.3% on follow up. This study concluded that once off parental education made negligible difference to an already inconsistent and haphazard approach to compliance with safety regulations.

Antimicrobial resistance of Campylobacter jejuni and Campylobacter coli isolates from broiler chickens isolated at an Irish poultry processing plant

AIMS

The antibiotic susceptibility of Campylobacter jejuni and Campylobacter coli isolates from broiler chickens were determined in order to evaluate the level of antibiotic resistance of Campylobacter species in the Irish poultry industry.

METHODS AND RESULTS

Seventy-eight Camp. jejuni and 22 Camp. coli strains were examined for susceptibility to eight antibiotics using the disc diffusion assay. The highest level of resistance of the Camp. jejuni isolates was recorded to ampicillin (35.9%), followed by 20.5% to tetracycline, 20.5% to naladixic acid, 17.9% to ciprofloxacin, 10.2% to erythromycin, 2.5% to streptomycin and 1.2% to kanamycin. Multidrug resistance to two or more antibiotics was seen for 30.7% of Camp. jejuni strains. Resistance of the Camp. coli isolates was shown to ampicillin (9%) and tetracycline (18.2%).

CONCLUSIONS

The majority of Camp. jejuni strains were susceptible to antibiotics commonly used for human therapy. Camp. coli strains showed very low resistance levels and were susceptible to six of the eight antimicrobial agents studied.

SIGNIFICANCE AND IMPACT OF THE STUDY

Levels of Camp. jejuni and Camp. coli antimicrobial resistance in Irish poultry production was assessed to determine the current situation in Ireland. The prevalence of antibiotic resistance of Campylobacter strains isolated from broiler chickens was low.

Relapse in the skull after myeloablative therapy for high-risk neuroblastoma

Patterns of relapse were determined for 20 high-risk neuroblastoma patients treated with chemotherapy, surgery, primary and metastatic site radiation (21 Gray), myeloablative chemotherapy, peripheral blood stem cell rescue, and 13-cis-retinoic acid. The median follow-up duration after transplant is 21 months (range, 8-34 months). The event-free survival and overall survival at 2 years were 45 and 75%, respectively. There were 2 primary site recurrences. Metastatic sites that became MIBG-scan negative on induction chemotherapy were not irradiated. Four patients relapsed in irradiated metastatic sites, 3 in the skull, 1 in the liver. Failure also occurred at 2 skull sites treated with chemotherapy only, and at 5 new sites: 1 skull, 2 distant lymph nodes, and 2 bones other than skull. Eight of 20 patients had skull metastasis at presentation; 6 were irradiated and 3 were controlled. Skull metastasis warrants more aggressive evaluation and treatment.

CXCR-4 desensitization is associated with tissue localization of hemopoietic progenitor cells

The chemokine stroma-derived factor (SDF)-1, and its receptor, CXCR-4, have been shown to be essential for the translocation of hemopoietic stem cells from the fetal liver to the bone marrow (BM). We hypothesized that if CXCR-4 plays a crucial role in the localization of human hemopoiesis, stem cells from distinct tissue sources should demonstrate distinct CXCR-4 expression or signaling profiles. CD34(+) cells from BM were compared with blood: either mobilized peripheral blood or umbilical cord blood. Unexpectedly, significantly higher levels of CXCR-4 surface expression on CD34(+) cells from blood sources, mobilized peripheral blood, or cord blood were observed compared with BM (p = 0.0005 and p = 0.002, respectively). However, despite lower levels of CXCR-4, responsiveness of the cells to SDF-1 as measured by either calcium flux or transmigration was proportionally greatest in cells derived from BM. Further, internalization of CXCR-4 in response to ligand, associated with receptor desensitization, was significantly lower on BM-derived cells. Therefore, preserved chemokine receptor signaling was highly associated with marrow rather than blood localization. To test the functional effects of perturbing CXCR-4 signaling, adult mice were exposed to the methionine-SDF-1beta analog that induces prolonged down-regulation/desensitization of CXCR-4 and observed mobilization of Lin(-), Sca-1(+), Thy-1(low), and c-kit(+) hemopoietic progenitor cells to the peripheral blood with a >30-fold increase compared with PBS control (p = 0.0007 day 1 and p = 0.004 day 2). These data demonstrate that CXCR-4 expression and function can be dissociated in progenitor cells and that desensitization of CXCR-4 induces stem cell entry into the circulation.

PCR-ELISAs for the detection of Campylobacter jejuni and Campylobacter coli in poultry samples

Campylobacter species, primarily Campylobacter jejuni and Campylobacter coli, are regarded as a major cause of human gastrointestinal disease, commonly acquired by eating undercooked chicken. We describe a PCR-ELISA for the detection of Campylobacter species and the discrimination of C. jejuni and C. coli in poultry samples. The PCR assay targets the 16S/23S ribosomal RNA intergenic spacer region of Campylobacter species with DNA oligonucleotide probes designed for the specific detection of C. jejuni, C. coli, and Campylobacter species immobilized on Nucleo-Link wells and hybridized to PCR products modified with a 5' biotin moiety. The limit of detection of the PCR-ELISA was 100-300 fg (40-120 bacterial cells) for C. jejuni and C. coli with their respective species-specific oligonucleotide probes and 10 fg (4 bacterial cells) with the Campylobacter genus-specific probe. Testing of poultry samples, which were presumptive positive for Campylobacter following culture on the Malthus V analyzer, with the PCR-ELISA determined Campylobacter to be present in 100% of samples (n = 40) with mixed cultures of C. jejuni/C. coli in 55%. The PCR-ELISA when combined with culture pre-enrichment is able to detect the presence of Campylobacter and definitively identify C. jejuni and C. coli in culture-enriched poultry meat samples.

Deletion of 3'-CBFB gene in association with an inversion (16)(p13q22) and a loss of the Y chromosome in a 2-year-Old child with acute myelogenous leukemia-M4

Inversion 16(p13q22) is most commonly associated with acute myelomonocytic leukemia with abnormal eosinophils (M4). In association with this inversion, a proximal deletion at the 16p13 primary arm breakpoint occurs in 20% of cases. We report on a first case of inversion 16 with a distal deletion at the primary arm breakpoint 16q22, detected by using the fluorescent-labeled dual-color probe CBFB.

Minor capsid protein of human genital papillomaviruses contains subdominant, cross-neutralizing epitopes

Vaccination with virus-like particles (VLP), comprising both L1 and L2 of human papillomavirus (HPV) genital types 6, 16, and 18, induces predominantly type-specific neutralizing antibodies. L2 polypeptide vaccines protect animals against experimental challenge with homologous papillomavirus and cross-reactive epitopes are present in HPV L2. To assess L2-specific cross-neutralization of HPV genotypes, sheep were immunized with purified, bacterially expressed HPV6, 16, or 18 L2. In addition to neutralizing the homologous HPV type in vitro, antisera to each HPV L2 also cross-neutralized both heterologous HPV types. This suggests that unlike VLP-based prophylactic HPV vaccines, an L2 polypeptide vaccine may provide broad-spectrum protection.

Detection and differentiation of Campylobacter jejuni and Campylobacter coli in broiler chicken samples using a PCR/DNA probe membrane based colorimetric detection assay

Campylobacter enteritis in humans has been linked to consumption of poultry meat. Surveys show that 30-100% of poultry harbour Campylobacter as normal flora of the digestive tract which indicates a need to identify prevalent organism types in flocks and trace their epidemiology. In this study we describe a Campylobacter genus specific polymerase chain reaction (PCR) assay, amplifying the 16 S-23 S rRNA intergenic spacer region with an internal Campylobacter genus specific DNA probe and species specific probes for Campylobacter jejuni and Campylobacter coli designed for confirmation of the amplified PCR products by Southern blot and colorimetric reverse hybridization assays. The specificity of this assay was established by testing a range of food pathogens. Broiler chicken samples were tested following presumptive positive identification by the Malthus System V analyser (Malthus Instruments, UK). The combined PCR and colorimetric reverse hybridization assay is easy to perform and faster than conventional methods for confirmation and identification of Campylobacter species.

Identification of CD56 and CD57 by flow cytometry in Ewing's sarcoma or primitive neuroectodermal tumor

CD56 and CD57 are commonly considered as natural killer and neuroectodermal markers, but their expression has been identified in a wide spectrum of neoplasms including some cases of Ewing's sarcoma (ES) and primitive neuroectodermal tumor (PNET). We report two cases of small, round blue cell tumor (SRBCT), in which flow cytometry immunophenotyping (FCI) detected strong expression of CD56 and CD57 (one case). Immunohistochemical staining with Leu-19 and Leu-7 confirmed the FI results. Although CD56 and CD57 expression is consistent with ES/PNET, it can be potentially misleading if results of FCI are interpreted in the absence of other findings. These cases suggest the utility of FCI in undifferentiated SRBCT. The literature on CD56 and CD57 expression in ES/PNET is reviewed and discussed.

Synthesis and properties of DNA-PNA chimeric oligomers

Adenine, thymine and cytosine PNA monomers have been prepared using 3-amino-1,2-propanediol as a starting material. The benzoyl group was used to protect the exocyclic amines of the heterocyclic bases of A and C PNA monomers and the backbone primary amine was protected with the monomethoxytrityl group. The thymine and cytosine PNA monomers were used in conjunction with standard DNA synthesis monomers to produce chimeric PNA DNA (PDC) oligomers. Ultraviolet melting studies confirmed that these oligomers form stable hybrids with complementary DNA strands and that mismatches in the DNA but more so in the PNA sections lead to duplex destabilisation.

Effects of weaning on antibody responses in young calves

Two experiments were performed to investigate the effects of cessation of feeding milk substitute (weaning) on antibody responses to Keyhole Limpet haemocyanin (KLH) in young calves. In the first experiment, 47 calves were weaned at 42 days of age, while a further 47 calves remained unweaned until 84 days of age. All calves were immunized with KLH at 43 and 85 days of age. Serum IgG1, IgG2 and IgA responses to KLH were increased in the early weaned calves compared with the late weaned calves following both primary and secondary immunizations. In the second experiment, 24 calves were immunized with KLH at 21 days of age. Subsequently, at 35 days of age, eight calves were weaned, eight calves were sham-weaned and eight calves remained unweaned. Sham-weaning involved continuing to feed milk substitute of greatly decreased nutritional value in an attempt to isolate nutritional from behavioural effects of weaning. No effects of treatments on antibody responses were detected. It was concluded that weaning affects antibody responses to antigens given near weaning but not to antigens given 2 weeks before weaning.

Compartment syndrome: a quantitative study of high-energy phosphorus compounds using 31P-magnetic resonance spectroscopy

The purpose of this study was to quantitate the intracellular high-energy phosphate compounds during 6 hours of tissue ischemia in the anterior tibial compartment of beagles subjected to an induced traumatized compartment syndrome. The goal of this work was to provide clinicians with objective criteria to augment clinical judgment regarding surgical intervention in the impending compartment syndrome. A beagle model was utilized in which the Delta pressure (difference between the mean arterial pressure and compartment pressure) could be controlled. The model, in conjunction with 31P-magnetic resonance spectroscopy (MRS), allowed a measure of high-energy phosphate compounds and pH in the compartment at various Delta pressures. The extent of ischemic metabolic insult in the compartment was then quantitated. Our data suggest the following: 1) lower Delta pressures result in a proportionally greater drop in the intracellular phosphocreatine ratio and pH; 2) at lower Delta pressures, there is proportionally greater decline in the percentage recovery post-fasciotomy; 3) blood pressure is extremely important and periods of hypotension may result in increased muscle damage at lower compartment pressures.

Enzyme-labeled DNA probes

Many research workers and clinicians working in routine laboratories are now using the "tools" developed by molecular biologists over the past 10 years to produce DNA sequences that can be used as probes to detect specific genes. Thus it is possible to screen food for salmonella (1) or other organisms in a test much more quickly than conventional methods involving culturing the organisms. The presence of certain types of human papillomavirus in cervical smears can be used as an indicationof neoplasia (2). DNA probes can also be used to screen antenatally for diseases such as sickle cells anemia (3) or β°-thalassemia (4).

Reversible, lectin-mediated immobilization of plant protoplasts on agarose beads

A technique is described for the reversible, lectin-mediated immobilization of plant protoplasts on agarose beads. Cyanogen-bromide-activated agarose beads were coated with protein (gelatine or bovine serum albumin) and lectins were subsequently linked to the protein layer using glutaraldehyde. The technique has possible applications in protoplast fusion-product isolation, cellrecognition studies, and membrane isolation.