Lineage tracing demonstrates the venous origin of the mammalian lymphatic vasculature.

The origin of the mammalian lymphatic vasculature has been debated for more than 100 years. Whether lymphatic endothelial cells have a single or dual, venous or mesenchymal origin remains controversial. To resolve this debate, we performed Cre/loxP-based lineage-tracing studies using mouse strains expressing Cre recombinase under the control of the Tie2, Runx1, or Prox1 promoter elements.

How well do pediatric anesthesiologists agree when assigning ASA physical status classifications to their patients?

Background: The scope and application of the American Society of Anesthesiologists Physical Status (ASA PS) classification has been called into question and interobserver consistency even by specialist anesthesiologists has been described as only fair. Our purpose was to evaluate the consistency of the application of the ASA PS amongst a group of pediatric anesthesiologists.

Methods: We randomly selected 400 names from the active list of specialist members of the Society for Pediatric Anesthesia.

Secondary chromosomal abnormalities predict outcome in pediatric and adult high-stage Burkitt lymphoma.

Background: Karyotypic abnormalities in sporadic Burkitt lymphoma (BL) have been described extensively. However, to the authors' knowledge, very limited studies have focused on the secondary chromosomal abnormalities in pediatric BL as compared with those of adult BL and on their prognostic impact.

Methods: A retrospective analysis was performed in all pediatric and adult patients at 2 institutions, with a morphologic diagnosis of BL, pretherapy tumor karyotype available, and t(8;14), t(8;22), or t(2;8) present.

Transcriptional regulation of fatty acid biosynthesis in Streptococcus pneumoniae.

The transcriptional regulation of membrane fatty acid composition in the human pathogen Streptococcus pneumoniae is distinct from the systems utilized in the model organisms Escherichia coli and Bacillus subtilis. The genes encoding the components of type II fatty acid biosynthesis cluster at a single location within the S. pneumoniae genome, and the second gene in this cluster (SPR0376) encodes a transcription factor (FabT) that belongs to the MarR superfamily.

The genesis of a pandemic influenza virus.

Pandemic influenza viruses pose a significant threat to public health worldwide. In a recent Nature paper, Taubenberger et al. (2005) now report remarkable similarities between the polymerase genes of the influenza virus that caused the 1918 Spanish influenza pandemic and those of avian influenza viruses.

Domain swapping between Enterococcus faecalis FabN and FabZ proteins localizes the structural determinants for isomerase activity.

Anaerobic unsaturated fatty acid synthesis in bacteria occurs through the introduction of a double bond into the growing acyl chain. In the Escherichia coli model system, FabA catalyzes both the dehydration of beta-hydroxydecanoyl-ACP and the isomerization of trans-2-decenoyl-ACP to cis-3-decenoyl-ACP as the essential step. A second dehydratase, FabZ, functions in acyl chain elongation but cannot carry out the isomerization reaction.

WASP- mice exhibit defective immune responses to influenza A virus, Streptococcus pneumoniae, and Mycobacterium bovis BCG.

Objective: To quantify the immune response of WASP- mice to three different pathogens: influenza A virus, Streptococcus pneumoniae, and Mycobacterium bovis.

Methods: Primary and secondary T-cell responses to influenza A virus were quantified via tetramer assays. Viral clearance from lung was also measured.

Brain T1 in young children with sickle cell disease: evidence of early abnormalities in brain development.

Measurement of tissue spin lattice relaxation time (T(1)) has been used to characterize brain development in healthy children. Here we report the first study of brain T(1) in young children with sickle cell disease (SCD). The T(1) in 10 tissue samples was measured by established techniques; 46 SCD patients under the age of 4 years were compared to 267 controls, including 55 well children under the age of 4 years.

Early multicenter experience with a noninvasive expandable prosthesis.

A noninvasive expandable prosthesis for skeletally immature children after limb salvage surgery has been developed. Between 1998 and 2001, 18 Phenix prostheses were implanted in 15 pediatric patients who had been diagnosed and treated for osteosarcoma about the knee. Of the 15 original prostheses, 10 were implanted at the time of primary tumor resection and five were revisions from an endoprosthetic modular knee system.

Online exclusive: functional integration of nursing research into a pediatric oncology cooperative group: finding common ground.

Purpose/objectives: To provide a brief description of the historic role of nursing and nursing research in the culture of previous pediatric oncology cooperative groups and compare the research language used in cooperative groups with the language used in nursing research.

Data Sources: Published empirical, clinical, and methodologic reports.

Data Synthesis: The culture and language of nursing research differ from those of medical research and the pediatric oncology cooperative group, the Children's Oncology Group (COG).

Guidelines for the recurrence of pediatric cancer.

Objectives: To provide practice guidelines to assist patients and parents in coping with a return of disease.

Data Sources: Delphi studies, review, and research articles.

Conclusions: When a child's cancer recurs, the patient and parents are at risk of physical and psychologic difficulties.

Describing the value of specialized distance education in pediatric oncology nursing.

Working as specialists in a changing environment, advanced practice nurses in pediatric oncology (APN-POs) benefit from specific pediatric oncology education. The graduates of a pediatric nurse practitioner program in pediatric oncology completed a survey about their educational experience and its impact on their current practice. This practitioner program included a subspecialty education in pediatric oncology and an early form of distance learning.

Identification of genes potentially involved in LMO2-induced leukemogenesis.

The most common translocations in childhood T cell acute lymphoblastic leukemias involve the LMO2 locus on chromosome 11p13 and cause ectopic expression of the LMO2 gene in thymocytes. Transgenic mice with enforced expression of LMO2 in their thymocytes develop T cell leukemias thus demonstrating the role of LMO2 in leukemogenesis. The physiologic and leukemogenic functions of LMO2 are mediated through its transcriptional regulatory activities, but the identity of the target genes is completely unknown.

Effect of food and pharmacokinetic variability on didanosine systemic exposure in HIV-infected children. Pediatric AIDS Clinical Trials Group Protocol 144 Study Team.

The effect of food on didanosine bioavailability and interpatient pharmacokinetic variability was examined in children infected with human immunodeficiency virus type 1 (HIV-1). Didanosine pharmacokinetics were determined during fasting and fed conditions in HIV-infected children enrolled in the Pediatric AIDS Clinical Trials Group Protocol 144 randomized to receive didanosine at 50 mg/m2 or 150 mg/m2 orally every 12 hr. Pharmacokinetic parameters from patients in the low (n = 39) and high (n = 38) dosing groups were not significantly different, but intersubject variability was substantial.

The impact of margin of resection on outcome in pediatric nonrhabdomyosarcoma soft tissue sarcoma.

Background/purpose: Because the management of pediatric nonrhabdomyosarcoma soft tissue sarcomas (NRSTS) is determined by extrapolation from adult studies, the effect of margin of tumor resection and postoperative radiation therapy (RT) on local tumor recurrence in children has not been assessed.

Methods: Records of NRSTS patients from a single institution were reviewed with regard to demographic data, TNM staging, grade, histological type and site of primary tumor, RT, and local tumor recurrence. The margin of resection was determined by pathological review and did not necessarily reflect operative margins.

Protection against a lethal avian influenza A virus in a mammalian system.

The question of how best to protect the human population against a potential influenza pandemic has been raised by the recent outbreak caused by an avian H5N1 virus in Hong Kong. The likely strategy would be to vaccinate with a less virulent, laboratory-adapted H5N1 strain isolated previously from birds. Little attention has been given, however, to dissecting the consequences of sequential exposure to serologically related influenza A viruses using contemporary immunology techniques.

Treatment of unresectable or metastatic pediatric soft tissue sarcomas with surgery, irradiation, and chemotherapy: a Pediatric Oncology Group study.

Background: The objectives of this study were to compare vincristine/actinomycin D/cyclophosphamide/adriamycin (VACA) with VACA/plus imidazole carboxamide (DTIC) (VACAD) therapy in regards to complete/partial response and event free survival rates in children and adolescents with metastatic non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) or previously chemotherapy-naive recurrent NRSTS or locally persistent gross residual tumor after surgery and radiation therapy.

Procedures: Between 1986 and March 1994, 75 patients entered this randomized study comparing VACA and VACAD, given at 3 week intervals. Sixty-one patients were considered eligible and received chemotherapy and radiation therapy to the primary tumor and areas of metastases.

Acute Lymphoblastic Leukemia.

Acute lymphoblastic leukemia (ALL) accounts for 25% of childhood cancer. Clinical and biological parameters define prognostic categories and therapeutic approaches. For the majority of children with B-progenitor ALL, age (1-9 yrs) and white blood count (WBC<50,000) indicate standard risk disease; WBC>50,000 and age>9 yrs.

Present day concepts of thoracoscopy as a modality in pediatric cancer management.

Recent improvements in video imaging and instrumentation have encouraged a wider use of thoracoscopy as a modality for diagnostic procedures. Its utility for resection is still being reviewed. To assess the utility, diagnostic accuracy, and morbidity of thoracoscopy in children with cancer, we reviewed the experience at our institution.

Inflammatory leukocytic recruitment and diffuse neuronal degeneration are separate pathological processes resulting from traumatic brain injury.

The present study characterized whether inflammatory leukocytic infiltration is temporally and regionally correlated with neuronal degeneration and/or blood brain barrier (BBB) breakdown resulting from traumatic brain injury. Adult rats were sacrificed at 5 min, 2, 4, 12, 24, and 72 hr after lateral fluid percussion brain injury. BBB breakdown, neuronal degeneration and leukocyte infiltration were assessed using immunocytochemistry, silver impregnation and toluidine blue and eosin staining.

Use of fluorescence resonance energy transfer to estimate intramolecular distances in the Msx-1 homeodomain.

We have utilized fluorescence resonance energy transfer (FRET) to investigate the spatial proximities of segments in the Msx-1 homeodomain (Msx). This strategy makes use of a single, invariant tryptophan (Trp-48) in helix III as the donor for FRET. The acceptor molecule, 5-[[[(iodoacetyl)amino]-ethyl]amino]naphthalene-1-sulfonic acid (AEDANS), was incorporated into Msx at positions 6, 10, or 27 which are within the N-terminal arm, and helices I and II since these segments have been implicated in interactions with helix III.

Childhood leukemias--current status and future perspective.

Current chemotherapy will cure at least 65% of children with acute lymphoblastic leukemia (ALL). The major challenge in ALL is to develop effective risk-directed therapy. This approach seeks to improve outcome, through more intensive therapy, for children at high risk of relapse, while reducing the side effects and long-term complications of treatment for those with a high likelihood of cure.

Heterogeneity of rat encephalitogenic T cells elicited by variants of the myelin basic protein (68-86) peptide.

By immunizing Lewis rats with myelin basic protein (MBP) peptide variants derived from the major encephalitogenic epitope of guinea pig (MBP(68-88) and then isolating encephalitogenic T cells from these animals, we demonstrated that the variant peptides do not elicit the same encephalitogenic T cell subsets as those induced by the wild-type peptide or by intact MBP. Rather, the pathogenic T cells differed in clonal composition as reflected by their heterogeneous responses to a panel of variant peptides and by their T cell receptor usage. Thus, molecules mimicking the MBP(68-88) autoantigen can elicit pathogenic T cell subsets without necessarily cross-reacting with T cells specific for the original autoantigen.