Validation of a 3-Dimensional-Printed Infant Tibia for Intraosseous Needle Insertion Training

INTRODUCTION

Current bone models used for pediatric intraosseous (IO) placement training are expensive or lack anatomic and/or functional fidelity. This technical report describes the development and validation of a 3-dimensional printed (3DP) tibia from a pediatric lower extremity computed tomography scan for IO procedural training.

METHODS

Multiple 3DP tibia models were printed using a dual-extrusion fused-filament fabrication printer. Models underwent iterative optimization until 2 final models, one of polypropylene (3DP clear) and the other of polylactic acid/polypropylene (3DP white), were selected. Using an exploratory sequential mixed-methods design, a novel IO bone model assessment tool was generated. Physicians then used the assessment tool to evaluate and compare common IO bone models to the novel 3DP models during IO needle insertion.

RESULTS

Thirty physicians evaluated the provided pediatric IO bone models. Compared with a chicken bone as a reference, the 3DP white bone had statistically significantly higher mean scores of anatomy, heft, sense of being anchored in the bone, quality of bone resistance, and "give" when interfaced with an IO needle. Twenty-two of the 30 participants ranked the 3DP white bone as either 1st or 2nd in terms of ranked preference of pediatric IO bone model. A 3DP white bone costs $1.10 to make.

CONCLUSIONS

The 3DP IO tibia models created from real-life computed tomography images have high degrees of anatomic and functional realism. These IO training models are easily replicable, highly appraised, and can be printed at a fraction of the cost of commercially available plastic models.

Assessing the Utility of Urine Testing in Febrile Infants 2 to 12 Months of Age With Bronchiolitis

BACKGROUND

The utility of testing for urinary tract infection (UTI) in febrile infants with bronchiolitis is indeterminate.

OBJECTIVE

The objective of this study was to investigate if the incidence of UTIs in febrile infants 2 to 12 months of age with bronchiolitis is higher than the presumed incidence of asymptomatic bacteriuria and determine risk factors associated with UTIs in this population.

METHODS

This prospective multicenter cross-sectional study was conducted in the emergency departments of 6 children's hospitals between November 2011 and June 2015. We obtained a convenience sample of febrile infants with bronchiolitis 2 to 12 months of age who were tested for UTI. Patient characteristics analyzed included age, maximum temperature, duration of fever, ethnicity, sex, and circumcision status.

RESULTS

A total of 442 patients (including 86 from a previously published pilot study) were enrolled. Mean age was 5.5 months, 65.2% were Latino, 50.9% were male, and 27.6% of male infants were circumcised. Urinary tract infections were found in 33 patients (7.69%, binomial; 95% confidence interval [CI], 5.19%-10.33%). Urinary tract infections were not related to age, height of temperature, duration of fever, or ethnicity. Uncircumcised males were significantly more likely to have UTIs than circumcised males (7.64% vs 0%, P = 0.03). Odds ratios (ORs) were lower for circumcised males but not uncircumcised males when compared with females (OR, 0.12; CI, 0.0-0.71; P = 0.01 vs OR, 0.77; CI, 0.33-1.74; P = 0.64).

CONCLUSIONS

Febrile infants 2 to 12 months of age with bronchiolitis have a clinically significant incidence of UTI, suggesting that UTI evaluation should be considered in these patients.

Quantitative proteomic characterization of cellular pathways associated with altered insulin sensitivity in skeletal muscle following high-fat diet feeding and exercise training

Regular exercise elicits advantageous metabolic adaptations in skeletal muscle, such as improved insulin sensitivity. However, the underpinning molecular mechanisms and the effect of diet on muscle exercise training benefits are unclear. We therefore characterized the skeletal muscle proteome following exercise training (ET) in mice fed chow or high-fat diet (HFD). ET increased exercise performance, lowered body-weight, decreased fat mass and improved muscle insulin action in chow- and HFD-fed mice. At the molecular level, ET regulated 170 muscle proteins in chow-fed mice, but only 29 proteins in HFD-fed mice. HFD per se altered 56 proteins, most of which were regulated in a similar direction by ET. To identify proteins that might have particular health-related bearing on skeletal muscle metabolism, we filtered for differentially regulated proteins in response to ET and HFD. This yielded 15 proteins, including the major urinary protein 1 (MUP1), which was the protein most decreased after HFD, but increased with ET. The ET-induced Mup1 expression was absent in mouse muscle lacking functional AMPK. MUP1 also potentiated insulin-stimulated GLUT4 translocation in cultured muscle cells. Collectively, we provide a resource of ET-regulated proteins in insulin-sensitive and insulin-resistant skeletal muscle. The identification of MUP1 as a diet-, ET- and AMPK-regulated skeletal muscle protein that improves insulin sensitivity in muscle cells demonstrates the usefulness of these data.

Localised impedance monitoring device for the remote clinical assessment of home-based dialysis patients

BioImpedance Spectroscopy (BIS) has been clinically used to determine the hydrational status of patients undergoing haemodialysis (HD). In the present project we are developing a calf-localised, integrated impedimetric device to periodically and conveniently measure and transmit information on the hydrational status of home-based patients to a remote clinic. Surprisingly, we have found that simple postural changes before or during measurement lead to significant fluid shifts in the lower leg that are as important and as long lasting as the effects of haemodialysis. These must be taken into account if potentially hazardous errors are not to be made in assessing a patient's hydrational status.

Birefringence of flow-assembled chitosan membranes in microfluidics

Biopolymer membrane assembly in microfluidics offers precise spatial and temporal resolution for biomolecular and cellular interactions during and after assembly. Control over molecular transport across the biofabricated membranes requires microstructural characterization. This study investigates, for the first time, the birefringence of chitosan membranes assembled with flow in a microfluidic environment, and the effects of pH and flow rate on the membrane's micro-alignment. The optical anisotropy of the formed membranes was quantified using a de Sénarmont compensator for transmitted quantitative polarized light microscopy. The chitosan membranes were biofabricated within a small aperture in a microfluidic network with various flow and pH conditions of chitosan and alginate solutions. The measured optical retardance and parallelism index clearly indicate that the microstructure of the flow-assembled membrane was well organized and aligned along the direction of chitosan flow. Optical retardance increased significantly with the pH of the alginate solution, but was less sensitive to the variation of the flow rates of the polymer solutions during the biofabrication process. It was also determined that the birefringence signal dropped significantly across the membrane growth direction regardless of the molecular density in the membrane. The mechanism of the micro-alignment was discussed, which was presumably due to the molecular un-wrapping by shear flow. We envision that the current study paves a path to further understand and actively manipulate the microstructure of flow-assembled membranes for broad lab-on-a-chip applications.

March of the Living, a Holocaust Educational Tour: An Assessment of Anxiety and Depression

March of the Living (MOTL) is a 2-week international educational tour for high school seniors to learn about the Holocaust by visiting concentration/deaths camps and other Jewish historical sites in Poland, culminating in a week-long excursion in Israel. Although the trip is primarily educational, there is recent research evidence to suggest that attendees may suffer from a variety of mental health sequelae. To determine symptoms of anxiety and depression, 196 Los Angeles delegation participants voluntarily completed the State-Trait Anxiety Inventory, composed of a trait anxiety scale (i.e., STAI-T) and a state anxiety scale (i.e., STAI-S), and the Center for Epidemiologic Studies Depression Scale (CES-D). Pre-MOTL, students completed an initial background questionnaire along with the STAI-T, STAI-S, and the CES-D. At end-Poland and end-Israel, the STAI-S and CES-D were administered again. Results demonstrated that depression scores increased during end-Poland and returned to baseline; however, anxiety scores mildly increased end-Poland and rose slightly more and persisted through end-Israel.

Characterization of microstructural injury: a novel approach in infant abusive head trauma-initial experience

Abusive head trauma (AHT) is the leading cause of morbidity and mortality among abused children, yet the neuroanatomical underpinnings of AHT outcome is incompletely understood. The aim of this study was to characterize white matter (WM) abnormalities in infants with AHT using diffusion tensor imaging (DTI) and determine which microstructural abnormalities are associated with poor outcome. Retrospective DTI data from 17 infants (>3 months) with a diagnosis of AHT and a comparison cohort of 34 term infants of similar post-conceptual age (PCA) were compared using a voxel-based DTI analysis of cerebral WM. AHT cases were dichotomously classified into mild/moderate versus severe outcome. Clinical variables and conventional imaging findings were also analyzed in relation to outcome. Outcomes were classified in accordance with the Pediatric Cerebral Performance Category Score (PCPCS). Reduced axial diffusivity (AD) was shown in widespread WM regions in the AHT infants compared with controls as well as in the AHT severe outcome group compared with the AHT mild/moderate outcome group. Reduced mean diffusivity (MD) was also associated with severe outcome. Radial diffusivity (RD), conventional magnetic resonance findings, brain metric measurements, and clinical/laboratory variables (with the exception of Glascow Coma Scale) did not differ among AHT outcome groups. Findings support the unique role of DTI techniques, beyond conventional imaging, in the evaluation of microstructural WM injury of AHT. Reduced AD (likely reflecting axonal damage) and MD were associated with poor clinical outcome. DTI abnormalities may uniquely reflect AHT patterns of axonal injury that are not characterized by conventional imaging, which may have both therapeutic and prognostic implications.

Bioinformatic investigation of the cost management strategies of five oral microbes

Some amino acids are more energetically costly to synthesize de novo, therefore many microbes have evolved to regulate the metabolic expenditure of the cell and reduce the energy burden of extracellular unrecyclable proteins. Several oral bacterial species take up amino acids and peptides obtained from proteolysis of host proteins and hence do not rely only on de novo synthesis. The aim of this study was to investigate if five oral bacterial species implement cost management strategies to reduce the energy burden of extracellular unrecyclable proteins. Since the relative de novo amino acid synthesis costs are proportional to the masses of the amino acids, the energy costs of producing proteins were assessed by calculating the mean amino acid mass for each protein. For Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Prevotella intermedia and Streptococcus sanguinis, the outer membrane/extracellular proteins are made up of a much larger percentage of lower average mass amino acids whereas cytoplasmic proteins are made up of a larger proportion of higher average mass amino acid residues. These results are consistent with the five oral bacterial species employing energy-saving mechanisms in the production of extracellular unrecyclable proteins. Interestingly, the P. gingivalis and S. sanguinis genomes exhibited significantly lower predicted mean amino acid masses compared with those of the genomes of the other three species, suggesting that this may provide them with an energy advantage with respect to protein biosynthetic cost.

Evidence for the role of EPHX2 gene variants in anorexia nervosa

Anorexia nervosa (AN) and related eating disorders are complex, multifactorial neuropsychiatric conditions with likely rare and common genetic and environmental determinants. To identify genetic variants associated with AN, we pursued a series of sequencing and genotyping studies focusing on the coding regions and upstream sequence of 152 candidate genes in a total of 1205 AN cases and 1948 controls. We identified individual variant associations in the Estrogen Receptor-ß (ESR2) gene, as well as a set of rare and common variants in the Epoxide Hydrolase 2 (EPHX2) gene, in an initial sequencing study of 261 early-onset severe AN cases and 73 controls (P=0.0004). The association of EPHX2 variants was further delineated in: (1) a pooling-based replication study involving an additional 500 AN patients and 500 controls (replication set P=0.00000016); (2) single-locus studies in a cohort of 386 previously genotyped broadly defined AN cases and 295 female population controls from the Bogalusa Heart Study (BHS) and a cohort of 58 individuals with self-reported eating disturbances and 851 controls (combined smallest single locus P<0.01). As EPHX2 is known to influence cholesterol metabolism, and AN is often associated with elevated cholesterol levels, we also investigated the association of EPHX2 variants and longitudinal body mass index (BMI) and cholesterol in BHS female and male subjects (N=229) and found evidence for a modifying effect of a subset of variants on the relationship between cholesterol and BMI (P<0.01). These findings suggest a novel association of gene variants within EPHX2 to susceptibility to AN and provide a foundation for future study of this important yet poorly understood condition.

March of the living, a holocaust educational tour: effect on adolescent Jewish identity

March of the Living (MOTL) is a worldwide two-week trip for high school seniors to learn about the Holocaust by traveling to sites of concentration/death camps and Jewish historical sites in Poland and Israel. The mission statement of MOTL International states that participants will be able to "bolster their Jewish identity by acquainting them with the rich Jewish heritage in pre-war Eastern Europe." However, this claim has never been studied quantitatively. Therefore, 152 adolescents who participated in MOTL voluntarily completed an initial background questionnaire, a Jewish Identity Survey and a Global Domains Survey pre-MOTL, end-Poland and end-Israel. Results suggest that Jewish identity did not substantially increase overall or from one time period to the next.

What mom and dad don't know can hurt you: adolescent disclosure to and secrecy from parents about type 1 diabetes

OBJECTIVE

To examine how adolescent disclosure to and secrecy from parents were related to parental knowledge of diabetes management behaviors, and to adolescent adherence, metabolic control, and depressive symptoms.

METHODS

A total of 183 adolescents with type 1 diabetes reported on disclosure to and secrecy from parents regarding diabetes management, adherence behaviors, depressive symptoms, and perceptions of parental knowledge. Mothers and fathers reported on their own knowledge.

RESULTS

Adolescent disclosure was associated with all reporters' perceptions of knowledge. Secrecy from both parents moderated the relationship between disclosure and adherence, and secrecy from fathers moderated the relationship between disclosure to fathers and glycosylated hemoglobin level. In all cases, disclosure was associated with better diabetes management only when secrecy was low. Finally, higher secrecy related to greater adolescent depressive symptoms.

CONCLUSIONS

Disclosure to parents appears to be an important component of how parents get their knowledge about adolescents' diabetes management, but may be most beneficial for diabetes management when it occurs together with low secrecy.

Parental involvement and adolescents' diabetes management: the mediating role of self-efficacy and externalizing and internalizing behaviors

OBJECTIVE

To examine mediating processes linking parental involvement to diabetes management (adherence and metabolic control) during adolescence.

METHODS

A total of 252 young adolescents (M age = 12.49 years, SD = 1.53, 53.6% females) with type 1 diabetes reported their parents' involvement in diabetes management (relationship quality, monitoring, and behavioral involvement), their own externalizing and internalizing behaviors, diabetes-self efficacy, and adherence behaviors. HbA1c was drawn from medical records.

RESULTS

SEM analyses indicated that the associations of mothers' and fathers' relationship quality with diabetes outcomes were mediated by adolescents' perceptions of self-efficacy and externalizing behaviors, and the associations of fathers' monitoring and behavioral involvement with adherence were partially mediated by adolescents' self-efficacy. There were also direct (non-mediated) associations between mothers' monitoring and adherence, and fathers' monitoring and adherence and metabolic control.

CONCLUSIONS

Quality of the parent-adolescent relationship and monitoring are important for better adherence and metabolic control among adolescents through higher diabetes self-efficacy.

[Molecular biology and hepatocellular carcinoma: current status and future prospects]

Hepatocellular carcinoma (HCC) is among the fifth most common cancers worldwide. Its incidence is still rising in part because of the high level of hepatitis C virus infection. Tumor markers currently used such as serum alpha-foetoprotein are not sufficient for diagnosis of the tumor and satisfying follow-up of the patients. Mechanisms of hepatocarcinogenesis ar not completely understood although several altered genes have been described in HCC. The genetic changes involved can be divided in at least 4 different pathways, each pathway contributing to a limited number of tumors. These are: 1) the p53 pathway involved in response to DNA damage, 2) the retinoblastoma pathway involved in the control of the cell cycle, 3) the transforming growth factor-beta (TGF-beta) pathway involved in growth inhibition, and 4) the Wnt pathway involved in cell-cell adhesion and signal transduction. Alterations of the epigenetic regulation of gene expression have also been described. Evolution of molecular biology methods tends to the development of more global genomic approaches; microsatellite instability analysis, chromosomal instability analysis or gene expression profile analysis have been used to investigate HCC. Finally, attempts to develop molecular biomarkers based on peripheral blood analysis more easily accessible in clinical routine patients have also been developed.

Crystal structure of a DinB family error-prone DNA polymerase from Sulfolobus solfataricus

A new group of error-prone DNA polymerases overcomes the blockage posed to normal DNA replication by damaged template bases, suggesting an active site with a loose, flexible pocket that accommodates aberrant DNA structures. We have determined a 2.8 A resolution crystal structure of the Sulfolobus solfataricus Dbh protein, a DNA translesion polymerase closely related to Escherichia coli DNA polymerase IV and human polymerase kappa. A high error rate is observed for the Dbh polymerase in a range of 10(-2)-10(-3) for all 12 base substitution mispairs. The crystal structure of Dbh reveals an overall architecture resembling other DNA polymerases but has unique features that are likely to contribute to error-prone synthesis, including -1 frameshifting mutations.

Detection of gammopathy by serum protein electrophoresis for predicting and managing therapy of lymphoproliferative disorder in 911 recipients of liver transplants

Monitoring of posttransplantation lymphoproliferative disorder (LPD) is usually based on imaging, which lacks sensitivity. A prospective study in 911 consecutive recipients of liver transplants was conducted to assess the value of gammopathy monitoring by serum protein electrophoresis (SPE) and to compare it with conventional follow-up methods. Patients systematically underwent SPE testing just before transplantation, at least twice during the first year after transplantation, and once a year thereafter. Patients with LPD underwent SPE testing every month. Immunofixation was done if abnormalities were detected by SPE. Gammopathy was observed in 114 patients, 18 of whom had onset of LPD. In 3 other patients, LPD developed, but no gammopathy was detected before onset of LPD or while LPD was present. Multivariate analyses showed gammopathy (relative risk [RR], 65.3), more than one transplantation (RR, 7.5), and viral cirrhosis (RR, 2.8) to be independent prognostic factors associated with occurrence of LPD. LPD was treated by reducing immunosuppression, with or without chemotherapy, administration of anti-CD20 monoclonal antibody, or surgery. The mortality rate was 24% (5 of 21 patients). Remission, which occurred in 13 patients, was associated with disappearance of gammopathy in 10 patients. In 5 patients, normalization of SPE results preceded the diagnosis of remission based on imaging, by a mean of 4 months. For diagnosis of LPD remission, the positive and negative predictive values of disappearance of gammopathy were 91% and 100%, respectively; and gammopathy monitoring was more sensitive than imaging (100% and 38%, respectively). Gammopathy monitoring is an inexpensive, noninvasive, sensitive way to detect LPD and assess the efficacy of treatment. It could be used routinely in follow-up of recipients of transplants.

Roles of DNA polymerases V and II in SOS-induced error-prone and error-free repair in Escherichia coli

DNA polymerase V, composed of a heterotrimer of the DNA damage-inducible UmuC and UmuD(2)(') proteins, working in conjunction with RecA, single-stranded DNA (ssDNA)-binding protein (SSB), beta sliding clamp, and gamma clamp loading complex, are responsible for most SOS lesion-targeted mutations in Escherichia coli, by catalyzing translesion synthesis (TLS). DNA polymerase II, the product of the damage-inducible polB (dinA ) gene plays a pivotal role in replication-restart, a process that bypasses DNA damage in an error-free manner. Replication-restart takes place almost immediately after the DNA is damaged (approximately 2 min post-UV irradiation), whereas TLS occurs after pol V is induced approximately 50 min later. We discuss recent data for pol V-catalyzed TLS and pol II-catalyzed replication-restart. Specific roles during TLS for pol V and each of its accessory factors have been recently determined. Although the precise molecular mechanism of pol II-dependent replication-restart remains to be elucidated, it has recently been shown to operate in conjunction with RecFOR and PriA proteins.

The ChromaGen contact lens system: colour vision test results and subjective responses

The ChromaGen lens system is designed to enhance colour perception in colour vision deficiency (CVD). To investigate its efficacy, 14 CVD subjects were prescribed ChromaGen contact lenses. Colour vision tests (Ishihara, Farnsworth Munsell D-15, Farnsworth Lantern) were administered at baseline, lens dispensing, and after a 2-week lens-wearing trial during which subjective responses were recorded daily using visual analogue scales. ChromaGen lenses significantly reduced ishihara error rates (p < 0.001; ANOVA), particularly for deutan subjects. There was also a significant reduction in errors (p < 0.005) on the D-15 test. Conversely, lens wear had no significant effect on Farnsworth Lantern test performance. Subjectively, subjects reported enhanced colour perception, but poor vision in dim light. Judgement of distance and motion were only slightly affected. We conclude that ChromaGen lenses may enhance subjective colour experience and assist in certain colour-related tasks, but are not indicated as an aid for CVD in occupations with colour vision-related restrictions.

A model for SOS-lesion-targeted mutations in Escherichia coli

The UmuD'2C protein complex (Escherichia coli pol V) is a low-fidelity DNA polymerase (pol) that copies damaged DNA in the presence of RecA, single-stranded-DNA binding protein (SSB) and the beta,gamma-processivity complex of E. coli pol III (ref. 4). Here we propose a model to explain SOS-lesion-targeted mutagenesis, assigning specific biochemical functions for each protein during translesion synthesis. (SOS lesion-targeted mutagenesis occurs when pol V is induced as part of the SOS response to DNA damage and incorrectly incorporates nucleotides opposite template lesions.) Pol V plus SSB catalyses RecA filament disassembly in the 3' to 5' direction on the template, ahead of the polymerase, in a reaction that does not involve ATP hydrolysis. Concurrent ATP-hydrolysis-driven filament disassembly in the 5' to 3' direction results in a bidirectional stripping of RecA from the template strand. The bidirectional collapse of the RecA filament restricts DNA synthesis by pol V to template sites that are proximal to the lesion, thereby minimizing the occurrence of untargeted mutations at undamaged template sites.

Health-risk behaviors among middle school students in a large majority-minority school district

Since 1991, the Centers for Disease Control and Prevention has administered the Youth Risk Behavior Survey (YRBS) biennially to representative samples of high school students. YRBS results indicate that health-risk behaviors often developed during middle school years. To date, few state and local education agencies have administered the YRBS-Middle School. This study measured prevalence of health-risk behaviors among middle school students in a large, majority-minority school district (n = 1,783). Results indicated that young adolescents (ages 11-14) are engaging in multiple health-risk behaviors. For example, 24.4% seriously considered committing suicide in the previous year, 53.3% had been in a physical fight, 50.2% ever drank alcohol, 17.9% ever used marijuana, and 13.4% had already had sex. Such behaviors potentially could lead to serious consequences related to their educational achievement and overall health status. Health-related policy and program applications are discussed.

Thyroid cancer: patients' experiences of receiving iodine-131 therapy

PURPOSE/OBJECTIVES

To enhance understanding of the experiences and educational needs of patients receiving iodine-131 (131I) therapy for the treatment of thyroid cancer.

DESIGN

Qualitative design using interpretive description.

SETTING

A 24-bed oncology/acute-care medical unit in a large tertiary hospital in western Canada.

SAMPLE

5 men and 22 women (18-80 years of age) who have received 131I therapy in the past two years.

METHODS

Unstructured focus group and telephone interviews and field notes. Interviews were tape-recorded, transcribed verbatim, and subjected to thematic analysis.

FINDINGS

Researchers elicited four major themes from the analysis: (a) recognizing the totality of the cancer experience, (b) being isolated, (c) recognizing the totality of the treatment experience, and (d) understanding barriers to treatment.

CONCLUSIONS

Healthcare providers require a better understanding of thyroid disease and the treatment and side effects of 131I therapy. Furthermore, educational programs are required to adequately prepare nurses and patients for future care.

IMPLICATIONS FOR NURSING PRACTICE

A need exists to improve the care and education provided to patients receiving 131I therapy. In particular, recognition of the totality of the cancer experience and the need for both staff and patient education were illustrated. If nurses are to provide comprehensive cancer care, both psychosocial and physical needs must be addressed and fulfilling these needs requires a collaborative approach among patients, nurses, and other healthcare professionals.

Roles of E. coli DNA polymerases IV and V in lesion-targeted and untargeted SOS mutagenesis

The expression of the Escherichia coli DNA polymerases pol V (UmuD'2C complex) and pol IV (DinB) increases in response to DNA damage. The induction of pol V is accompanied by a substantial increase in mutations targeted at DNA template lesions in a process called SOS-induced error-prone repair. Here we show that the common DNA template lesions, TT (6-4) photoproducts, TT cis-syn photodimers and abasic sites, are efficiently bypassed within 30 seconds by pol V in the presence of activated RecA protein (RecA*), single-stranded binding protein (SSB) and pol III's processivity beta,gamma-complex. There is no detectable bypass by either pol IV or pol III on this time scale. A mutagenic 'signature' for pol V is its incorporation of guanine opposite the 3'-thymine of a TT (6-4) photoproduct, in agreement with mutational spectra. In contrast, pol III and pol IV incorporate adenine almost exclusively. When copying undamaged DNA, pol V exhibits low fidelity with error rates of around 10(-3) to 10(-4), with pol IV being 5- to 10-fold more accurate. The effects of RecA protein on pol V, and beta,gamma-complex on pol IV, cause a 15,000- and 3,000-fold increase in DNA synthesis efficiency, respectively. However, both polymerases exhibit low processivity, adding 6 to 8 nucleotides before dissociating. Lesion bypass by pol V does not require beta,gamma-complex in the presence of non-hydrolysable ATPgammaS, indicating that an intact RecA filament may be required for translesion synthesis.

Hepatitis B knowledge among Vietnamese immigrants: implications for prevention of hepatocellular carcinoma

BACKGROUND

Vietnamese have higher liver cancer rates than any other racial/ethnic group in the United States. Approximately 80% of liver cancers are etiologically associated with hepatitis B virus (HBV) infection, which is endemic in Southeast Asia.

METHODS

A telephone survey of randomly selected Vietnamese households (n = 75) was conducted during 1998 to examine HBV knowledge among Seattle's Vietnamese community. The questionnaire included items related to the transmission of HBV, the possible sequelae of infection, and disease prevention.

RESULTS

The response rate was 70% among reachable and eligible households. Prior to being provided with a description of the disease, two thirds of our respondents had heard of HBV infection. Less than 60% knew that asymptomatic individuals can transmit the disease to others. Most thought that HBV infection can cause liver cancer (63%) and death (80%). However, only a minority knew that infection can be lifelong (38%) and incurable (22%). Finally, 28% had never heard of the HBV vaccine. There were significant associations between knowledge and educational level as well as home ownership.

CONCLUSIONS

The findings suggest that Vietnamese immigrants have low levels of knowledge about HBV infection, and indicate a need for targeted educational interventions aimed at reducing HBV-related liver cancer mortality.

Acute cyclosporine toxicity after liver transplantation is predicted by the lidocaine monoethylglycinexylidide test in the donor

Cyclosporine toxicity is still a significant problem in the early period after liver transplantation. The monoethylglycinexylidide (MEGX) test performed in the donor has been suggested as a reliable test to predict liver graft function in the recipient. The MEGX test was performed in 50 consecutive donors, and the clinical course of recipients, metabolic parameters of the grafts, and cyclosporine levels were followed in detail for 10 days. Two patients died of sepsis and were excluded. Renal and/or neurological toxicity appeared in 15 of the remaining 48 patients (31%). In the 6 with neurological problems, MEGX values were low (41, 47, 50, 60, 94, and 101 micrograms/L). Nine patients had transient elevations of creatinine and urea; in 8 of these, cyclosporine levels remained in the normal range. Low MEGX values in the donors correlated with early evidence of cyclosporine toxicity (P < .0001), reduced graft function (bile output, P = .04; prothrombin time at day 5, P = .005), and prolonged stay in the intensive care (P = .022). The MEGX test is valuable and reflects the metabolic capacity of liver grafts. It can predict posttransplantation complications caused by cyclosporine toxicity, and further study would evaluate its incorporation into immunosuppressive protocols.

Prospective evaluation of circulating hepatocytes by alpha-fetoprotein mRNA in humans during liver surgery

OBJECTIVE

The objective of this study was to analyze the specificity of detecting liver tumor cell dissemination by alpha-fetoprotein (AFP) mRNA in peripheral blood.

SUMMARY BACKGROUND DATA

Alpha-fetoprotein mRNA has been used for the detection of circulating micrometastatic tumor foci of hepatocellular carcinoma (HCC); however, the interpretation of the results has been equivocal.

METHODS

Sixty-four consecutive patients with malignant HCC (n = 20), liver metastases (n = 27), or nonmalignant (n = 17) liver diseases undergoing partial or total hepatectomy and orthotopic liver transplantation were included in this prospective study from January to July 1995. Peripheral blood samples were obtained before surgery, during surgery, and after surgery (range, 6-15 months). Total mRNA was extracted from nucleated cells, and cDNA synthesis and polymerase chain reaction amplification (nested polymerase chain reaction in one tube) were performed with specific AFP primers.

RESULTS

Preoperative AFP mRNA was detected in 20 patients (17%), of which 5 of 20 had HCC. Intraoperative assessment showed positive AFP mRNA values in a total of 34 patients (53%) with various causes, of which 8 of 20 (40%) had HCC, 17 of 27 (63%) had other malignancies, and 9 of 17 (53%) had nonmalignant diseases. Recurrent tumor in patients with HCC occurred in four cases after surgery (range, 6-15 months) and did not correlate with AFP mRNA positivity before surgery, during surgery, or after surgery.

CONCLUSIONS

Alpha-fetoprotein mRNA in peripheral blood is not a specific marker of circulating micrometastases from HCC, especially in the context of surgical treatment of HCC.

Regulation of angiotensin II receptor subtypes by dexamethasone in rat mesangial cells

The objective of this study was to examine the role of dexamethasone on the expression of angiotensin II (Ang II) receptors in cultured rat mesangial cells. Dexamethasone caused concentration- and time-dependent decreases in 125I-[Sar1,Ala8]Ang II binding that were prevented by glucocorticoid receptor inhibition with mifepristone. A lag time of 24 hours and a dexamethasone concentration of at least 10 nmol/L were necessary for this effect to occur. Dexamethasone-induced reduction of 125I-[Sar1,Ala8]Ang II binding resulted from decreased Ang II type 1 (AT1) receptor density. No change in the apparent dissociation constant was observed. Dexamethasone also markedly inhibited Ang II-dependent inositol phosphate accumulation. Both reverse transcription-polymerase chain reaction and Northern blot analysis using specific short probes from the 3' noncoding region of the cDNA demonstrated the presence of AT1A and AT1B receptor mRNAs in rat mesangial cells, with a slight predominance of AT1B. Therefore, we studied the effect of dexamethasone on the expression of these two subtypes in rat mesangial cells. Dexamethasone produced a time-dependent decrease of AT1B receptor mRNA that was apparent after 6 hours of incubation, whereas AT1A receptor mRNA did not change. Mifepristone also suppressed the dexamethasone-induced decrease in AT1B receptor mRNA. In conclusion, glucocorticoids diminish Ang II receptor density at the mesangial cell surface through a mechanism that implies successive interaction with the glucocorticoid receptor and specific reduction in AT1B receptor mRNA expression. This differential regulation of both AT1 receptor subtypes might allow glucocorticoids to exert adjusted effects in their various target tissues.

Molecular analysis of lymphoid malignancies

Although lymphoid malignancies have been widely studied at the molecular level, no group has reported on the simultaneous investigation of t(14;18) chromosomal translocation, B-cell clonality and bcl2 gene expression. We have performed PCR analysis of t(14;18) translocation and B-cell clonality as well as semi-quantitation of bcl2 expression by Western blotting on a group of 41 patients treated at our institution for lymphoid malignancies. The t(14;18) translocation was observed in 10 out of 40 cases (25%) with a prevalence in the subgroup of centrofollicular lymphoma (9 out of 19, or 47%, which includes one patient in complete clinical remission). bcl2 was overexpressed in 84% of the patients (21/25) and B monoclonality was observed in 21 out of 37 B-cell neoplasia patients (57%) with or without a t(14;18) translocation. In 4 patients, bcl2 overexpression, which has been implicated in the sensitivity to a variety of cytotoxic drugs, was the only abnormality detected. Studies are currently underway to determine whether semi-quantitation of bcl2 expression provides improved prediction of a patient's response to chemotherapy.

Plasma levels and molecular forms of proatrial natriuretic peptides in healthy subjects and in patients with congestive heart failure

A specific and sensitive radioimmunoassay (RIA) for the N-terminal fragment of proatrial natriuretic peptide (NproANP) was developed. Antiserum raised in rabbits against a mixture enriched with prohormone was 100% cross-reactive with human proANP(1-30). Plasma concentrations of proANP(1-30) and ANP immunoreactivities (ir-) were simultaneously measured in healthy subjects and patients with congestive heart failure (CHF; 26 dilated cardiomyopathy and 5 ischemic heart disease). High plasma levels of both ir-proANP(1-30) and ir-ANP were detected in CHF patients. Circulating ir-ANP levels were elevated in New York Heart Association functional Classes II and III patients but not in Class I patients. However, plasma levels of ir-proANP(1-30) were higher in asymptomatic patients than in healthy subjects, and markedly increased in patients of Classes II and III. Analysis of ir-proANP(1-30) by gel filtration chromatography or reverse-phase high pressure liquid chromatography revealed a 10 kDa peptide circulating as a distinct entity. These findings indicate that: (i) the most probable form of NproANP in human plasma is a 10 kDa peptide and (ii) in CHF patients the rise in plasma ir-proANP(1-30) levels is more pronounced than the variation in plasma ir-ANP. Thus, NproANP plasma levels may prove to be a more sensitive marker of left ventricular dysfunction than ANP.

Characterization of C-type natriuretic peptide receptors in human mesangial cells

Our aim was to examine whether the human glomerulus was a target for C-type natriuretic peptide (CNP) and how A, B and C receptors of natriuretic peptides (ANPR-A, ANPR-B, ANPR-C) were distributed in glomerular mesangial and epithelial cells. CNP stimulated cyclic GMP production in cultured human mesangial and epithelial cells with similar threshold concentrations (1 nM) and maximum effects (basal value x 30 at 1 microM). In contrast, atrial natriuretic peptide (ANP) was only stimulatory in epithelial cells. [125I] CNP bound specifically to mesangial cells with a Kd of 0.47 nM and Bmax of 42 fmol/mg. Equilibrium of binding was obtained after four to five hours at +4 degrees C and nonspecific binding represented 10 to 20% of total binding. HS142-1 (100 micrograms/ml), a specific inhibitor of ANPR-A and ANPR-B, suppressed 90% of CNP-dependent cyclic GMP production whereas it had little effect on [125I]-CNP binding, suggesting that C receptors were largely predominant in mesangial cells. No biological effect of CNP on mesangial cells, including change in basal or angiotensin II-induced contractility and inhibition of basal or serum-dependent proliferation, could be demonstrated. Similar results were obtained with 8-bromo-cyclic GMP and sodium nitroprusside. Intraglomerular localization of ANPR-A, ANPR-B and ANPR-C mRNA was studied using reverse transcriptase-polymerase chain reaction with amplification of their corresponding cDNA by different primers. Amplification products were identified on gel electrophoresis by their predicted sizes and sequencing. ANPR-A, ANPR-B and ANPR-C mRNA were present in epithelial cells whereas only ANPR-B and ANPR-C mRNA were detected in mesangial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential regulation of angiotensin II and losartan binding sites in glomeruli and mesangial cells

The aim of the present report was to examine the effect of several agents on angiotensin II (ANG II) and losartan receptors using 125I-[Sar1,Ala8]ANG II and [3H]losartan as radiolabeled ligand, respectively. ANG II receptors were downregulated in glomeruli from rats infused with ANG II during 3 wk or rats receiving losartan orally during 1 wk. The number of sites (Bmax) was reduced, but the dissociation constant (Kd) value was unchanged. Losartan receptors were downregulated in glomeruli from rats receiving losartan, but remained unchanged in glomeruli from rats infused with ANG II. Since in vivo administration of losartan results in increase of plasma ANG II and formation of metabolites, in vitro studies using human mesangial cells were performed to better analyze the present findings. Treatment of mesangial cells during 4 days by ANG II, losartan, or its metabolite, EXP-3174, also produced downregulation of 125I-[Sar1,Ala8]ANG II binding sites with a decreased Bmax and unchanged Kd value. Only treatment of mesangial cells by ANG II or EXP-3174 produced downregulation of [3H]losartan binding sites. In contrast, exposure of these cells to losartan resulted in upregulation of [3H]losartan binding sites. Under all conditions, only Bmax was modified. Whereas internalization of [3H]losartan in mesangial cells was negligible under all experimental conditions, there was an increase of the percentage of internalized 125I-[Sar1,Ala8]ANG II after exposure of the cells to ANG II or AT1 antagonists. No change was observed in mesangial cell AT1 receptor mRNA levels. This study demonstrates that 1) AT1 mRNA is expressed in human mesangial cells; 2) the characteristics of 125I-[Sar1,Ala8]ANG II and [3H]losartan binding sites in rat glomeruli and human mesangial cells are different, with Kd and Bmax values greater in both preparations when [3H]losartan was utilized; 3) both types of binding sites obey different regulations, and the effects of losartan in vivo are due in part to the associated increase in plasma ANG II levels and the transformation of the drug into its metabolite, EXP-3174; 4) downregulation of AT1 receptors does not depend on changes in mRNA expression but is associated with increased relative internalization.

Solubilization and characterization of d-fenfluramine binding sites from bovine cerebral cortex

Stable d-Fenfluramine binding activity was obtained in high yields, in cholate extracts of bovine cerebral cortex crude membrane preparations. Dissociation constant (Kd 17 nM), stereoselectivity and the rank order of potencies of various serotonin uptake inhibitors were similar to those measured in native membranes. The inhibitory effect of Na+ ions was also maintained in the soluble state, since the presence of 100 mM Na+ leads to an even greater reduction of the binding than in membrane-associated binding sites. Photoaffinity labeling of soluble binding sites with p-[125I]d-Fenfluramine has led to the identification of a single specific band of molecular weight around 40-50 kDa. This suggests that d-Fenfluramine binding sites are separate molecular entities from the serotonin transporter, that belongs to a family of integral membrane proteins of 68-73 kDa molecular weight.

Rapid development of learning-induced receptive field plasticity in the auditory cortex

Classical conditioning induces frequency-specific receptive field (RF) plasticity in the auditory cortex after relatively brief training (30 trials), characterized by increased response to the frequency of the conditioned stimulus (CS) and decreased responses to other frequencies, including the pretraining best frequency (BF). This experiment determined the development of this CS-specific RF plasticity. Guinea pigs underwent classical conditioning to a tonal frequency, and receptive fields of neurons in the auditory cortex were determined before and after 5, 15, and 30 CS-US (unconditioned stimulus) pairings, as well as 1 hr posttraining. Highly selective RF changes were observed as early as the first 5 training trials. They culminated after 15 trials, then stabilized after 30 trials and 1 hr posttraining. The rapid development of RF plasticity satisfies a criterion for its involvement in the neural bases of a specific associative memory.

Characterization of [3H]losartan receptors in isolated rat glomeruli

[3H]Losartan bound specifically to isolated rat glomeruli. Scatchard analysis revealed a single class of losartan binding sites with an apparent dissociation constant (KD) of 6.2 nM and a density of receptor sites (Bmax) of 1.2 pmol/mg protein. In comparison, [3H][Sar1,Ala8]angiotensin II binding sites exhibited the same KD value (4.3 nM), but a considerably lower Bmax (52 fmol/mg protein). Moreover whereas [125I][Sar1,Ala8]angiotensin II was almost equally displaced by angiotensin II, [Sar1,Ala8] angiotensin II and losartan, [3H]losartan was potently displaced by losartan only. Finally, [125I][Sar1,Ala8]angiotensin II but not [3H]losartan binding sites were sensitive to guanosine triphosphate (GTP) gamma S and Dithiothreitol. These data, together with the recent demonstration of intrinsic effects of losartan, support the view that [3H]losartan does not label only the angiotensin II type 1 receptor (AT1).

Rapid development of learning-induced receptive field plasticity in the auditory cortex

Classical conditioning induces frequency-specific receptive field (RF) plasticity in the auditory cortex after relatively brief training (30 trials), characterized by increased response to the frequency of the conditioned stimulus (CS) and decreased responses to other frequencies, including the pretraining best frequency (BF). This experiment determined the development of this CS-specific RF plasticity. Guinea pigs underwent classical conditioning to a tonal frequency, and receptive fields of neurons in the auditory cortex were determined before and after 5, 15, and 30 CS-US (unconditioned stimulus) pairings, as well as 1 hr posttraining. Highly selective RF changes were observed as early as the first 5 training trials. They culminated after 15 trials, then stabilized after 30 trials and 1 hr posttraining. The rapid development of RF plasticity satisfies a criterion for its involvement in the neural bases of a specific associative memory.

Characterization of angiotensin II receptor subtypes in human glomeruli and mesangial cells

This study was designed to identify the subtypes of angiotensin II (ANG II) receptors present on glomeruli and glomerular mesangial cells and establish their functional significance. Dup 753 and its metabolite EXP 3174, two nonpeptide ANG II-1 receptor (AT1) antagonists, displaced 125I-ANG II and its analogue 125I-[Sar1,Ala8]ANG II from their binding sites in rat and human glomeruli and cultured human mesangial cells, whereas CGP 42112 A and PD 123177, two ANG II-2 receptor (AT2) antagonists, exhibited little displacing activity. Dup 753 and EXP 3174 did not modify the dissociation constant (Kd) value but markedly decreased the number of sites of 125I-[Sar1,Ala8]ANG II binding. The addition of PD 123177 did not further inhibit binding when all AT1 sites were occupied by Dup 753. Binding was markedly reduced by dithiothreitol. EXP 3174 and Dup 753 inhibited the main biological functions of ANG II in mesangial cells including increases in intracellular calcium concentration, PGE2 production, and protein synthesis. PD 123177 was also active but at concentrations 1,000- to 10,000-fold greater than those of AT1 antagonists. These results indicate that 1) only AT1 receptors are present in glomeruli and glomerular mesangial cells; 2) these receptors mediate the functional responses to ANG II; 3) the nonpeptide AT1 antagonists behave as noncompetitive inhibitors; and 4) high concentrations of the nonpeptide AT2 antagonists can recognize AT1 sites.

Interleukin 4 induces interleukin 6 production by endothelial cells: synergy with interferon-gamma

Interleukin (IL)4 induces IL6 production by human umbilical vein endothelial cells (HUVEC) in a dose-dependent manner, as shown by bioassay and immunoprecipitation. Interferon (IFN)-gamma, which antagonizes IL4 effects on leukocytes, synergized with IL4 in the induction of IL6 production by HUVEC. Contamination with endotoxin was excluded by heat-inactivated IL4, preincubating with anti-IL4 polyclonal antibody and the use of polymyxin B. The presence of IL4 receptors on HUVEC was shown by affinity cross-linking with 125I-IL4, revealing a 110-kDa binding protein. However, compared with the amount seen on T cells the 60-70-kDa cross-linked doublet was present at much lower levels. Additional lower molecular weight cross-linked proteins were isolated only with HUVEC, but the origin of these is unclear. IL6 is a pluripotent cytokine produced by many cells which promotes the differentiation and growth of lymphocytes and the production of acute phase protein by hepatocytes, and is important in the regulation of immunity at the systemic and local levels. Since IL4 and IFN-gamma are produced by T cells, which are frequently associated with vascular endothelium during chronic inflammation, IL4 is likely to be an important cytokine in the regulation of IL6 and perhaps other cytokine production by endothelium in vivo.

Modification of the 31P magnetic resonance spectra of a rat tumour using vasodilators and its relationship to hypotension

The effects of different doses of hydralazine and prostacyclin on the 31P magnetic resonance spectra of the LBDS1 fibrosarcoma were investigated and related to their effects on mean arterial blood pressure (MABP) and heart rate. The effect of reducing MABP by bleeding the animals, via the tail artery, was also investigated. Tumour spectral changes following high dose drug treatment (an increase in inorganic phosphate, a reduction in nucleotide triphosphates and a reduction in pH) were consistent with nutrient deprivation. These changes were dose dependent. Changes in MABP and heart rate were consistent with vasodilatation in normal tissues. However, for the same fall in MABP, hydralazine produced a greater rise in tumour inorganic phosphate (Pi) and a greater fall in tumour pH than did prostacyclin. Controlled bleeding was effective in reducing MABP. It also reduced tumour pH but had no significant effect on tumour Pi. The clinical application of the two drugs for reducing tumour blood flow and pH for therapy is likely to be limited by the large degree of hypotension necessary to produce an effect. The differential effect of the two drugs for the same fall in MABP may be related to different degrees of direct tumour vasodilatation or to a direct effect of hydralazine on tumour energy metabolism. The observation that controlled bleeding does not change tumour Pi is further evidence indicating that the degree of arterial hypotension is not the sole factor in determining tumour energy status.

Characterization of atrial natriuretic factor receptors in human glomerular epithelial and mesangial cells

To evaluate the distribution and functions of receptors of atrial natriuretic factor (ANF) in human glomeruli, we studied the binding sites of ANF-(1-28) in homogeneous populations of human glomerular epithelial cells or mesangial cells. 125I-labeled ANF bound specifically to both cell types. Equilibrium saturation binding curves suggested one group of receptor sites in mesangial cells (Kd = 99 +/- 32 pmol/l, Bmax = 15.3 +/- 3.5 fmol/mg) but multiple groups in glomerular epithelial cells. Binding was greater at 37 than at 4 degrees C in mesangial cells. The reverse was observed in glomerular epithelial cells due to marked degradation of the tracer at 37 degrees C. The fractions of undisplaceable tracer in a hypertonic acid medium after 60 min incubation were 45 and 16% at 37 degrees C for glomerular epithelial and mesangial cells, respectively. ANF-(1-28) and C-ANF-(4-23), a specific ligand of clearance receptors, similarly inhibited 125I-ANF binding to mesangial cells, whereas [Ala7-Ala23]-ANF, a linear analogue, was slightly less potent. In epithelial cells, C-ANF-(4-23) competitively inhibited 125I-ANF binding but with a lower potency than ANF, whereas linear ANF at low concentrations (10-100 pmol/l) stimulated 125I-ANF binding. In addition, linear ANF markedly inhibited the degradation of 125I-ANF in the incubation medium of epithelial and mesangial cells, whereas thiorphan, an inhibitor of enkephalinase, was inactive. ANF-(1-28) stimulated cGMP production in glomerular epithelial cells but not in mesangial cells. Both analogues were inactive in both cell types and did not modify ANF-(1-28)-dependent cGMP synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

A randomized comparative study of artemisinine (qinghaosu) suppositories and oral quinine in acute falciparum malaria

In adult patients with acute falciparum malaria in Ho Chi Minh City, Vietnam, a more rapid reduction in parasite count (50% clearance in 11.3 h) and complete clearance (41.8 h) was obtained in 32 adult patients randomly assigned to received artemisinine suppositories than was obtained with 30 patients receiving oral quinine (20.8 h and 68.1 h). There were higher degrees of resistance (RII, 3 cases; RI early, 1 case) with quinine than with artemisinine but in a subgroup of patients quinine reduced parasitaemia as rapidly as artemisinine (50% clearance 13.6 h and 10.1 h respectively). Recrudescence (RI, delayed), occurred in 16 patients receiving artemisinine compared with 6 receiving quinine. Artemisinine suppositories, because of ease of administration, efficacy, and lack of side effects or risk of overdose, have advantages for the early treatment of falciparum malaria by possibly reducing the morbidity and mortality associated with a high or sustained parasitaemia.