bluuebunny/crossref_metadata_2025 huggingface dataset:
Estrogenic induction of spermatogenesis in the hypogonadal (hpg) mouse: role of androgens
Authors: Baines Helen , Nwagwu Margaret O , Furneaux Edwina C , Stewart Jane , Kerr Jeffrey B , Mayhew Terry M , Ebling Francis J P
Published: November 2005

Testicular development is arrested in the hypogonadal (hpg) mouse due to a congenital deficiency of hypothalamic gonadotropin-releasing hormone synthesis. Previous studies have demonstrated that chronic treatment of these mice with estradiol induces testicular maturation and qualitatively normal spermatogenesis, but it is not known whether these are direct effects via estrogen receptors expressed in the testis, or indirect actions via the pituitary gland. The aim of the current studies was to determine whether the actions of estradiol require the presence of androgens. Sensitive assays revealed that chronic estradiol treatment produced time-dependent increases in pituitary FSH production but no increases in pituitary LH or testicular testosterone content could be detected. As a functional test of androgen dependence,hpgmice were treated for 70 days with estradiol plus Casodex (bicalutamide), an androgen receptor antagonist. Casodex treatment markedly attenuated both the estradiol-induced increase in testicular weight and the proliferation of the seminiferous epithelium, as revealed by morphometric analysis. However, it did not affect the estradiol-induced increase in pituitary FSH content, nor did it affect estradiol-induced increases in the weight of the seminal vesicles and epididymides. We conclude that increased FSH production is not sufficient to explain the increase in testicular development induced by estradiol inhpgmice; there is a requirement for functional androgen receptors for induction of testicular growth.
Respiration rates of individual bovine in vitro-produced embryos measured with a novel, non-invasive and highly sensitive microsensor system
Authors: Lopes A S , Larsen L H , Ramsing N , Løvendahl P , Räty M , Peippo J , Greve T , Callesen H
Published: November 2005

Oxygen consumption is a useful parameter for evaluating embryo quality, since it provides a valuable indication of overall metabolic activity. Over the years, several approaches have been used to measure the respiration rates of individual embryos, but a convincing method has not yet been reported. In this study, we introduce and have validated a novel high resolution microsensor technology to determine the respiration rates of individual embryos at different developmental stages. We have employed this technology to investigate the correlation between respiration rate and embryo morphology, diameter and sex. Following morphological evaluation, individual respiration rates of day 3 (n= 18) and day 7 (n= 60) bovinein vitro-produced embryos were determined. Of the measured embryos, 64 were lysed for sex diagnosis by PCR. Average respiration rates of day 7 embryos (1.30 ± 0.064 nl/h) were 3.4-fold higher than day 3 embryos (0.38 ± 0.011 nl/h). On day 7, the average respiration rate of quality 1 blastocysts was significantly higher than the respiration rates of the lower qualities. For both day 3 and day 7 embryos, respiration rates were directly influenced by embryo diameter but did not differ between sexes. These results have demonstrated that the novel microsensor technology can be used to accurately and rapidly (8 min) measure the respiration rates of individual embryos at different developmental stages. Respiration rates were only in partial agreement with embryo morphology, suggesting a slight discrepancy between these two methods in assessing embryo quality. It is likely that a combined assessment of embryo respiration and morphology would improve embryo classification and subsequent selection.
Different expression and activity of the α1 and α4 isoforms of the Na,K-ATPase during rat male germ cell ontogeny
Authors: Wagoner K , Sanchez G , Nguyen A-N , Enders G C , Blanco G
Published: November 2005

Two catalytic isoforms of the Na,K-ATPase, α1 and α4, are present in testis. While α1 is ubiquitously expressed in tissues, α4 predominates in male germ cells. Each isoform has distinct enzymatic properties and appears to play specific roles. To gain insight into the relevance of the Na,K-ATPase α isoforms in male germ cell biology, we have studied the expression and activity of α1 and α4 during spermatogenesis and epididymal maturation. This was explored in rat testes at different ages, in isolated spermatogenic cells and in spermatozoa from the caput and caudal regions of the epididymis. Our results show that α1 and α4 undergo differential regulation during development. Whereas α1 exhibits only modest changes, α4 increases with gamete differentiation. The most drastic changes for α4 take place in spermatocytes at the mRNA level, and with the transition of round spermatids into spermatozoa for expression and activity of the protein. No further changes are detected during transit of spermatozoa through the epididymis. In addition, the cellular distribution of α4 is modified with development, being diffusely expressed at the plasma membrane and intracellular compartments of immature cells, finally to localize to the midregion of the spermatozoon flagellum. In contrast, the α1 isoform is evenly present along the plasma membrane of the developing and mature gametes. In conclusion, the Na,K-ATPase α1 and α4 isoforms are functional in diploid, meiotic and haploid male germ cells, α4 being significantly upregulated during spermatogenesis. These results support the importance of α4 in male gamete differentiation and function.
A rat model for functional characterization of pregnancy-induced denervation and postpartum reinnervation in the myometrium and cervix: a superfusion study
Authors: Zupkó I , Csonka D , Falkay G
Published: November 2005

The pregnancy-induced rapid degeneration of the adrenergic nerves innervating the uterus is a well-known but poorly understood phenomenon. Since most of the published investigations were carried out by histological assay, our aim was to describe the loss of the adrenergic function during pregnancy and the reinnervational procedure in the postpartum period. Myometrial and cervical samples from rats were loaded with [3H]noradrenaline and then transferred into a chamber for superfusion. After a wash-out period, fractions were collected. The fifth and fifteenth fraction tissues were stimulated with an electric field. The [3H]noradrenaline contents of the fractions were determined, together with the amount remaining in the tissue. The myometrial [3H]noradrenaline release was substantially decreased in early pregnancy, and absent in the late stage. Differences in release profile were detected between the implantation sites and the interimplantation areas. As a refinement of the results of previous histochemical studies, the noradrenergic functions of the cervix were found to be deeply affected in the early postpartum period. The pregnancy-induced denervational procedure can be followed by means of a superfusional technique after [3H]noradrenaline loading. As our technique is considered to be similar in sensitivity to histological methods, superfusion can be regarded as a model for functional investigations of pregnancy-induced denervation.
Embryo culture does not affect the longevity of offspring in mice
Authors: Sommovilla Joshua , Bilker Warren B , Abel Ted , Schultz Richard M
Published: November 2005

The oldest assisted reproductive technologies (ART)-conceived child is only 27 years old. Thus, the effects of ART on longevity are unknown, and it will be many years before this can be assessed in humans. We recently reported that culturing preimplantation mouse embryos under suboptimal conditions results in differences in how the offspring perform in behavioral assays that reflect anxiety (elevated zero maze) and spatial memory (Morris hidden water maze; Ecker et al. 2004). Here we monitored the mice generated in our previous study and found no difference in their longevity.
The Role of the N-Terminal Oligopeptide Repeats of the Yeast Sup35 Prion Protein in Propagation and Transmission of Prion Variants
Authors: Shkundina Irina S , Kushnirov Vitaly V , Tuite Mick F , Ter-Avanesyan Michael D
Published: November 2005

The cytoplasmic [PSI+] determinant of Saccharomyces cerevisiae is the prion form of the Sup35 protein. Oligopeptide repeats within the Sup35 N-terminal domain (PrD) presumably are required for the stable [PSI+] inheritance that in turn involves fragmentation of Sup35 polymers by the chaperone Hsp104. The nonsense suppressor [PSI+] phenotype can vary in efficiency probably due to different inheritable Sup35 polymer structures. Here we study the ability of Sup35 mutants with various deletions of the oligopeptide repeats to support [PSI+] propagation. We define the minimal region of the Sup35–PrD necessary to support [PSI+] as amino acids 1–64, which include the first two repeats, although a longer fragment, 1–83, is required to maintain weak [PSI+] variants. Replacement of wild-type Sup35 with deletion mutants decreases the strength of the [PSI+] phenotype. However, with one exception, reintroducing the wild-type Sup35 restores the original phenotype. Thus, the specific prion fold defining the [PSI+] variant can be preserved by the mutant Sup35 protein despite the change of phenotype. Coexpression of wild-type and mutant Sup35 containing three, two, one, or no oligopeptide repeats causes variant-specific [PSI+] elimination. These data suggest that [PSI+] variability is primarily defined by differential folding of the Sup35–PrD oligopeptide-repeat region.
Neuropathology in Drosophila Membrane Excitability Mutants
Authors: Fergestad Tim , Ganetzky Barry , Palladino Michael J
Published: November 2005

Mutations affecting ion channels and neuronal membrane excitability have been identified in Drosophila as well as in other organisms and characterized for their acute effects on behavior and neuronal function. However, the long-term effect of these perturbations on the maintenance of neuronal viability has not been studied in detail. Here we perform an initial survey of mutations affecting Na+ channels and K+ channels in Drosophila to investigate their effects on life span and neuronal viability as a function of age. We find that mutations that decrease membrane excitability as well as those that increase excitability can trigger neurodegeneration to varying degrees. Results of double-mutant interactions with dominant Na+/K+ ATPase mutations, which themselves cause severe neurodegeneration, suggest that excitotoxicity owing to hyperexcitability is insufficient to explain the resultant phenotype. Although the exact mechanisms remain unclear, our results suggest that there is an important link between maintenance of proper neuronal signaling and maintenance of long-term neuronal viability. Disruption of these signaling mechanisms in any of a variety of ways increases the incidence of neurodegeneration.
The Introduction of Computerized Physician Order Entry and Change Management in a Tertiary Pediatric Hospital
Authors: Upperman Jeffrey S. , Staley Patricia , Friend Kerri , Benes Jocelyn , Dailey Jacque , Neches William , Wiener Eugene S.
Published: November 2005

Objectives. The objectives of this review were to document the introduction of computerized physician order entry (CPOE)-centered changes in an academic tertiary care center and to review the CPOE-focused literature.

Design. We performed a systematic literature review of CPOE-related articles indexed on Medline, with particular emphasis on pediatric applications. We focused our commentary around the concepts involved in the implementation process at a tertiary pediatric hospital.

Results. In 2001, the Children’s Hospital of Pittsburgh (CHP) embarked on the process of CPOE design and implementation. We determined that CPOE is a tool for improving pediatric care. The CPOE implementation process is more than a technologic change; it involves an organizational cultural transformation. Although the complete transition to CPOE was little more than 1 year ago, CHP has overcome the typical obstacles of CPOE implementation to begin to realize its many benefits. The early success of CHP was achieved by creating a realistic, positive, work environment, which fostered hospital-wide participation and integration.

Conclusion. CPOE is an invaluable resource for supporting patient safety in health care settings. The successful implementation of CPOE requires a paradigm shift in hospital policies and processes.
Injury Prevention Advice in Top-Selling Parenting Books
Authors: Hunter Wanda M. , Helou Samah , Saluja Gitanjali , Runyan Carol W. , Coyne-Beasley Tamera
Published: November 2005

Objective. Parenting books are a commonly used source of information on how to keep children and adolescents safe from injuries, the leading cause of death and disability for children aged 1 to 18 years. The content and the quality of the messages contained in these books have not been evaluated formally. The objective of this study was to determine the quantity and the quality of injury prevention messages contained in popular parenting books.

Methods. Top-selling parenting books for 2 major booksellers were reviewed to determine the presence and the accuracy of injury prevention messages as compared with those recommended by the American Academy of Pediatrics (AAP) through The Injury Prevention Program (TIPP) for younger children, aged 0 to 12 years, and the American Medical Association (AMA) through its Parent Package for the safety of adolescents.

Results. Forty-six parenting books were reviewed, including 41 with messages related to younger children and 19 with messages related to adolescents. These books varied widely with regard to the number of injury prevention messages included. Although some books covered the great majority of TIPP messages for parents of young children, others included very few. In the case of books that address safety for adolescents, no book had more than half of the messages recommended by the AMA. Prevention of burns and motor vehicle injury were the most commonly addressed injury prevention topics in the books focused on younger children, whereas gun safety was the most prevalent injury prevention topic in books that focused on adolescents. Books that were authored by physicians addressed more of the recommended topics and messages than books that were written by authors from other professional backgrounds. The quality of messages was good, ie, consistent with the advice given by the AAP and the AMA. In only a few cases, the parenting books gave injury prevention advice that was inconsistent with recommendations.

Conclusions. Overall, books on parenting adolescents are less likely to contain injury prevention messages than those that address younger children. However, the most frequent injury prevention messages for parents of adolescents describe strategies to prevent firearm injury, a leading cause of death for children in this age group. More emphasis should be placed on prevention of motor vehicle injuries, especially as relates to adolescents. Pediatricians and primary care physicians need to be aware of the strengths and weaknesses of parenting manuals in providing adequate guidance related to injury prevention.
Helium/Oxygen-Driven Albuterol Nebulization in the Treatment of Children With Moderate to Severe Asthma Exacerbations: A Randomized, Controlled Trial
Authors: Kim In K. , Phrampus Erin , Venkataraman Shekhar , Pitetti Raymond , Saville Al , Corcoran Timothy , Gracely Ed , Funt Nicole , Thompson Ann
Published: November 2005

Background. Helium and oxygen mixtures (heliox) increase both pulmonary aerosol delivery and gas delivery relative to oxygen. We aimed to compare the effectiveness of a 70%:30% helium/oxygen (heliox)–driven continuous aerosol delivery versus 100% oxygen-driven delivery in the treatment of asthmatic children with moderate to severe exacerbations.

Methods. We enrolled 30 children aged 2 to 18 years who presented to an urban, pediatric emergency department (ED) with moderate to severe asthma as defined by a pulmonary index (PI) score of ≥8. PI scores can range from 0 to 15. In this randomized, controlled, single-blind trial conducted in a convenience sample of children, all patients in the trial received an initial nebulized albuterol (5 mg) treatment driven by 100% oxygen and a dose of oral prednisone or prednisolone. Subsequently, patients were randomly assigned to receive continuously nebulized albuterol (15 mg/hour) delivered by either heliox or oxygen using a nonrebreathing face mask. The primary outcome measure was degree of improvement as assessed in blinded video-recorded PI scores over 240 minutes (at 30-minute intervals for the first 3 hours) or until ED discharge (if <240 minutes).

Results. The mean change in PI score from baseline to 240 minutes or ED discharge was 6.67 for the heliox group compared with 3.33 for the oxygen group. Eleven (73%) patients in the heliox group were discharged from the hospital in <12 hours compared with 5 (33%) patients in the conventional group.

Conclusion. Continuously nebulized albuterol delivered by heliox was associated with a greater degree of clinical improvement compared with that delivered by oxygen among children with moderate to severe asthma exacerbations.
Characteristics of Pediatric Traumatic Amputations Treated in Hospital Emergency Departments: United States, 1990–2002
Authors: Hostetler Sarah Grim , Schwartz Lila , Shields Brenda J. , Xiang Huiyun , Smith Gary A.
Published: November 2005

Objective. To examine the characteristics of children with traumatic amputations and the products associated with these injuries.

Methods. Data regarding amputation injuries to children younger than 18 years treated in US emergency departments from 1990 to 2002 were obtained from the National Electronic Injury Surveillance System. Data included demographics, product involved, and body region injured.

Results. An estimated 111600 children younger than 18 years with amputation injuries were treated in US emergency departments from 1990 to 2002. The average age was 6.18 years (median: 4 years; mode: 1 year old). Males experienced 65.5% of these injuries. Finger amputations accounted for 91.6% of all amputations, ranging from 95.2% among 0- to 2-year-olds to 87.9% among 13- to 17-year-olds. Complete amputations accounted for 70.2% of all amputations among 13- to 17-year-olds compared with 52.6% of amputations among 0- to 2-year-olds. Adolescents also had the highest proportion of amputations resulting in hospital admission (26.6% for 13- to 17-year-olds compared with 11.9% for 0- to 2-year-olds). Adolescents had the highest proportion of amputation injuries involving lawn mowers (14.1% for 13- to 17-year-olds compared with 1.4% for 0- to 2-year-olds) and the highest proportion of amputations involving tools (29.3% for 13- to 17-year-olds compared with 2.5% for 0- to 2-year-olds). The percentage of amputations involving doors peaked in the youngest age group and decreased as age increased (65.8% of all amputations for 0- to 2-year-olds compared with 14.1% for 13- to 17-year-olds).

Conclusions. To our knowledge, this is the first study to use a nationally representative sample to broadly investigate amputation injuries among children. The majority of traumatic amputation injuries occur to young children, to males, and to fingers and the majority involve doors. Adolescents experience a higher proportion of more serious amputation injuries. Effective interventions exist but are inadequately used to prevent many of these injuries, including door stops and modifications, bicycle-chain and spoke guards, wearing closed-toe footwear while bicycling, a no–mow-in-reverse default feature on ride-on lawnmowers with the override switch located behind the mower operator, and a SawStop system on power saws. Use of these technical countermeasures and changes in relevant product standards to promote their implementation and use could lead to a decrease in pediatric traumatic amputations.
Development of the Metabolic Syndrome in Black and White Adolescent Girls: A Longitudinal Assessment
Authors: Morrison John A. , Friedman Lisa Aronson , Harlan William R. , Harlan Linda C. , Barton Bruce A. , Schreiber George B. , Klein David J.
Published: November 2005

Background. The metabolic syndrome, associated with increased risk of type 2 diabetes mellitus and cardiovascular disease, begins to develop during adolescence.

Objective. We sought to identify early predictors of the presence of the syndrome at the ages of 18 and 19 years in black and white girls.

Methods. Using longitudinal data on participants from 2 centers in the National Heart, Lung, and Blood Institute Growth and Health Study, a 10-year cohort study, we applied cutoffs from the Adult Treatment Panel III to document changes in the prevalence of abnormal syndrome elements and the syndrome in girls aged 9 and 10 years, when cases were rare, and those aged 18 and 19 years, when prevalence had reached 3%. Longitudinal regression models identified early predictors for the presence of the syndrome.

Results. Only 1 girl of each race had ≥3 factors at ages 9 and 10 (0.2%), but 20 black girls (3.5%) and 12 white girls (2.3%) had the syndrome 10 years later. Low high-density lipoprotein cholesterol was prevalent throughout the period in both black and white girls. The prevalence of other variables was low at enrollment but increased during follow-up, except for abnormal triglyceride levels in black girls, which remained low throughout follow-up. In multivariate models, early measures of waist circumference and triglyceride level were significant predictors for development of the syndrome.

Conclusion. The strong association of central adiposity with the development of the metabolic syndrome suggests that early interventions aimed at managing preteen obesity could reduce risk of developing the syndrome.
Clinical (Video) Findings and Cerebrospinal Fluid Neurotransmitters in 2 Children With Severe Chronic Bilirubin Encephalopathy, Including a Former Preterm Infant Without Marked Hyperbilirubinemia
Authors: Merhar Stephanie L. , Gilbert Donald L.
Published: November 2005

Chronic bilirubin encephalopathy, characterized clinically by extrapyramidal movement abnormalities, vertical gaze abnormalities, and hearing loss, results from neuronal injury after marked hyperbilirubinemia in term and preterm infants. In premature infants, bilirubin staining of specific brain structures has been described at autopsy after only moderate hyperbilirubinemia, but classic chronic bilirubin encephalopathy without marked hyperbilirubinemia has been reported only rarely. We report a case of a 7-year-old, former 29-weeks' gestation, gravely ill premature infant with a peak bilirubin level of 13.3 mg/dL in the neonatal period. We compare this case with a 12-year-old, former term infant with a peak bilirubin level of 49.4 mg/dL on day 10 of life. Both children have dystonia, athetosis, upward gaze palsy, and sensorineural hearing loss, with MRIs showing characteristic abnormal signal in the globus pallidus. We add previously unreported cerebrospinal fluid neurotransmitter levels that show a mild decrease in the dopamine metabolite homovanillic acid in the former premature infant only.
Epidemiology of Pediatric Tuberculosis Using Traditional and Molecular Techniques: Houston, Texas
Authors: Wootton Susan H. , Gonzalez Blanca E. , Pawlak Rebecca , Teeter Larry D. , Smith Kim Connelly , Musser James M. , Starke Jeffrey R. , Graviss Edward A.
Published: November 2005

Objective. To investigate the transmission dynamics of pediatric tuberculosis (TB) by analyzing the clinical characteristics with the molecular profiles of Mycobacterium tuberculosis isolates during a 5-year period.

Methods. A retrospective review of a prospective population-based active surveillance and molecular epidemiology project was conducted in private and public pediatric clinics within Houston and Harris County, Texas. The study population consisted of patients who had pediatric TB diagnosed from October 1, 1995, through September 30, 2000. Cases and potential source cases (PSC) were interviewed using a standardized questionnaire. Available Mycobacterium tuberculosis isolates from cases and PSCs were characterized and compared by IS6110 restriction fragment length polymorphism, spoligotyping, and genetic group assignment. Clinical characteristics were described, and molecular characterizations were compared. Data were analyzed by using EpiInfo 6.02b and SAS 8.2.

Results. A total of 220 (92%) of 238 pediatric TB cases were included. Epidemiologic and clinical findings were consistent with previous studies. Molecular profiles from 3 cases did not match the profile of PSC. Four previously unknown PSCs were identified using molecular techniques. Fifty-one (71.8%) of 71 isolates matched at least 1 other Houston Tuberculosis Initiative TB database isolate and were grouped into 33 molecular clusters. Cases were more likely to be clustered when the patients were younger than 5 years, identified a source case, or were US born.

Conclusions. Traditional contact tracing may not always be accurate, and molecular characterization can lead to identification of previously unrecognized source cases. Recent transmission plays a significant role in the transmission of TB to children as evident by the high degree of clustering found in our study population.
Apnea Is Not Prolonged by Acid Gastroesophageal Reflux in Preterm Infants
Authors: Di Fiore Juliann M. , Arko Marina , Whitehouse Meghan , Kimball Amy , Martin Richard J.
Published: November 2005

Objective. To examine the temporal relationship between apnea and gastroesophageal reflux (GER) and to assess the effect of GER on apnea duration.

Methods. A total of 119 preterm infants underwent 12-hour cardiorespiratory monitoring studies using respiratory inductance plethysmography, heart rate, oxygen saturation (SaO2), and esophageal pH. The studies were scored for GER (pH <4 for ≥5 seconds) and apnea ≥15 seconds or ≥10 seconds that occurred within 30 seconds of GER. Apnea ≥10 seconds was used to assess whether GER would prolong apnea duration.

Results. There were 6255 episodes of GER. Only 1% of GER episodes were associated with apnea ≥15 seconds, and there was no difference in apnea rate before, during, or after GER. There was also no difference in rate of apnea ≥10 seconds before versus during GER; however, there was a decrease in apnea rate immediately after GER. The presence of GER during apnea did not prolong apnea duration, and GER had no effect on the lowest SaO2 or heart rate during apnea.

Conclusion. There is no evidence of a temporal relationship between acid-based GER and apnea in preterm infants. In addition, GER does not prolong apnea duration and does not exacerbate the resultant decrease in heart rate and SaO2.
Medical Futility in the Neonatal Intensive Care Unit: Hope for a Resolution
Authors: Fine Robert L. , Whitfield Jonathan M. , Carr Barbara L. , Mayo Thomas W.
Published: November 2005

Contemporary medical practice in the NICU sometimes leads to conflicts between providers and parents in which the parent demands continuation of life-sustaining treatment that the medical team deems medically inappropriate or futile. Such conflicts can be difficult to resolve and trying for all parties. Here we describe a conflict involving a 25-week-gestation, 825-g newborn with multiple intractable medical problems and resolution of the conflict through ethics consultation under provisions of the Texas Advance Directives Act. The process established under Texas law sets conceptual and temporal boundaries around the problem of medical futility and provides a legal safe harbor for physicians who seek to withdraw life-sustaining treatments in the setting of medical futility, allowing resolution of such conflicts in a timely and effective manner. As such, it may provide a model for physicians in other states to follow.
Effectiveness of Iron Supplementation in a Young Child With Attention-Deficit/Hyperactivity Disorder
Authors: Konofal Eric , Cortese Samuele , Lecendreux Michel , Arnulf Isabelle , Mouren Marie Christine
Published: November 2005

A 3-year-old child was referred to consultation for hyperactivity, attention deficit, impulsivity, and sleep problems. He met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for attention-deficit/hyperactivity disorder. At baseline, the Conners’ Parent Rating Scale and the Conners’ Teacher Rating Scale raw total scores were 30 and 32, respectively. The child had low a serum ferritin level (13 ng/mL). After 8 months of treatment with Tardyferon (ferrous sulfate, 80 mg/day), his serum ferritin increased to 102 ng/mL. Both parents and teachers reported considerable behavioral improvement. The Conners’ Parent and Teacher Rating Scale raw total scores decreased to 19 and 13, respectively. This is the first report of the effectiveness of iron supplementation in a young child with attention-deficit/hyperactivity disorder.
Photochemical Behavior and Na+,K+ ‐ATPase Sensitivity of Voltage‐sensitive Styrylpyridinium Fluorescent Membrane Probes
Authors: Amoroso Steve , Agen Vanessa V. , Starke‐Peterkovic Thomas , McLeod Malcolm D. , Apell Hans‐Jürgen , Sebban Pierre , Clarke Ronald J.
Published: November 2005

RH421 is a widely used voltage‐sensitive fluorescent membrane probe. Its exposure to continuous illumination with 577 nm light from an Hg lamp leads, however, to an increase in its steady‐state fluorescence level when bound to lipid membranes. The increase occurs on the second time scale at typical light intensities and was found to be due to a single‐photon excited‐state isomerization. Modifications to the dye structure are, therefore, necessary to increase photochemical stability and allow wider application of such dyes in kinetic studies of ion‐transporting membrane proteins. The related probe ANNINE 5, which has a rigid polycyclic structure, shows no observable photochemical reaction when bound to DMPC vesicles on irradiation with 436 nm light. The voltage sensitivity of ANNINE 5 was tested with the use of Na+,K+‐ATPase membrane fragments. As long as ANNINE 5 is excited on the far red edge of its visible absorption band, it shows a similar sensitivity to RH421 in detecting charge‐translocating reactions triggered by ATP phosphorylation. Unfortunately the wavelengths necessary for ANNINE 5 excitation are in a region where the Hg lamps routinely used in stopped‐flow apparatus have no significant lines available for excitation.
Preclinical Perspectives on Bisphosphonate Renal Safety
Authors: Body Jean-Jacques , Pfister Thomas , Bauss Frieder
Published: November 2005

Renal insufficiency is not rare in cancer patients who may receive nephrotoxic medications as antineo-plastic agents or for comorbid conditions. Thus, the choice of a particular bisphosphonate for patients with metastatic bone disease should be based not only on efficacy but also on the risk for renal deterioration. Some i.v. bisphosphonates have been associated with occasional renal toxicity in the clinical setting. Preclinical studies have also shown that there may be considerable differences among bisphosphonate renal safety profiles. Comparative studies show variations in the risk for histopathologic damage and the ability to cause cumulative toxicity during intermittent dosing. Reasons for the differences among bisphosphonates are not fully understood; however, research shows that they may be influenced by pharmacokinetic properties such as renal tissue half-life or protein binding and intracellular potency. Further preclinical analyses are needed to confirm and evaluate differences among bisphosphonates.
Efficacy of Ibandronate in Metastatic Bone Disease: Review of Clinical Data
Authors: Bell Richard
Published: November 2005

Metastatic bone disease affects many cancer patients and has a significant disease burden because of complications such as pathologic fractures and severe pain, which affect patient mobility and quality of life. Bisphosphonates are the current standard of care for treating metastatic bone disease. Available agents have shown varying degrees of efficacy in clinical trials, and treatment potential can be limited by efficacy, tolerance, or toxicity issues. Ibandronate (Bondronat®; F. Hoffman-La Roche Ltd., Basel, Switzerland, http://www.roche.com) is a highly potent, single-nitrogen bisphosphonate that is available in i.v. and oral formulations. In phase III trials in breast cancer patients, both formulations reduced the incidence of skeletal complications associated with metastatic bone disease and had significant and sustained effects on bone pain and patient quality of life. Open-label studies of loading-dose ibandronate administered over consecutive days suggest it also may be useful for relieving severe or opioid-resistant metastatic bone pain. New trials have been designed or are in progress that may extend the clinical indications of ibandronate for patients with metastatic bone disease.
Pulsing to improve bubble column performance: II. Jetting gas rates
Authors: Knopf F. Carl , Waghmare Yogesh , Ma Jia , Rice Richard G.
Published: November 2005

The bubble column reactor (BCR) used in Part I was subjected to forced oscillations at high gas rates under jetting conditions. Two piston types were used: a flexible rubber membrane as used in Part I and a modification thereof to cause a more rigid, stiff piston behavior. The mass transfer performance differences between the piston types were quite remarkable, the former yielding peaking with respect to increased frequency and the latter produced monotonic increases up to an asymptote as the frequency was increased. The Benjamin–Ursell stability theory was found useful in tracking regimes of maximum enhancement. © 2005 American Institute of Chemical Engineers AIChE J, 2006
Second hit deletion size in von Hippel–Lindau disease
Authors: Gläsker Sven , Sohn Tae‐Sung , Okamoto Hiroaki , Li Jie , Lonser Russell R. , Oldfield Edward H. , Vortmeyer Alexander O. , Zhuang Zhengping
Published: November 2005

von Hippel–Lindau (VHL) disease is caused by germline mutations of the VHL tumor suppressor gene. Affected individuals are predisposed to development of multiple neoplastic and preneoplastic lesions of different organs. A “second hit,” which is usually represented by deletion in the wild‐type VHL allele at 3p25, is necessary for initiation of tumor formation. The impact of the size of this deletion is thought to be critical, because other tumor suppressor genes are located nearby, but this has not yet been studied in detail. We mapped the deletion size of the “second hit” in microdissected tissue from 16 different VHL‐associated lesions from the same patient using 10 polymorphic chromosome 3 markers. We found that the deletion size is highly variable, ranging from short deletions around the VHL gene to complete loss of the chromosome 3. The deletion sizes are not correlated with the site of the germline mutation, the affected organ, or the type or biological behavior of the tumor. Even preneoplastic cystic structures may harbor entire loss of the chromosome 3, suggesting that loss of VHL gene function alone is not immediately causative for neoplastic growth, but further events, either mutations and deletions in other chromosomes or epigenetic or other than genetic phenomena, are required for tumor formation. Ann Neurol 2005
A novel superporous agarose medium for high‐speed protein chromatography
Authors: Shi Qing‐Hong , Zhou Xin , Sun Yan
Published: November 2005

A novel superporous agarose (SA) bead characterized by the presence of wide pores has been fabricated by water‐in‐oil emulsification using solid granules of calcium carbonate as porogenic agent. After cross‐linking, the solid granules were removed by dissolving them in hydrochloric acid. Then, the gel was modified with diethylaminoethyl groups to create an anion exchanger, SA‐DEAE, for protein adsorption. A homogeneous agarose (HA) bead was also produced and modified with DEAE for comparison. It was found that the porosity of SA‐DEAE was about 6% larger than that of HA‐DEAE. Moreover, both optical micrographs and confocal laser scanning microscopy (CLSM) of the ion exchangers with adsorbed fluorescein isothiocyanate (FITC) labeled IgG revealed the superporous structure of the SA medium. In addition, the SA‐DEAE column had lower backpressure than the HA‐DEAE column, confirming the convective flow of mobile phase through the wide pores. Due to the presence of the wide pores, more channels were available for protein transport and, furthermore, more diffusive pores in the agarose network were accessible for the protein approach from different directions. This led to 40% higher protein capacity and two times higher effective pore diffusivity in the SA‐DEAE than in HA‐DEAE. Moreover, an increase of the efficiency of the SA‐DEAE column until a flow rate of 5 cm/min and the independency of the column efficiency at flow rates from 5 to 17.8 cm/min was found, indicating that intraparticle mass transfer was intensified by convective flow at elevated flow rates. Therefore, the chromatographic resolution of IgG and BSA was little affected up to a flow rate of 17.8 cm/min. The results indicate that the SA medium is favorable for high‐speed protein chromatography. © 2005 Wiley Periodicals, Inc.
Terpenoid indole alkaloid production by Catharanthus roseus hairy roots induced by Agrobacterium tumefaciens harboring rol ABC genes
Authors: Hong Seung‐Beom , Peebles Christie A.M. , Shanks Jacqueline V. , San Ka‐Yiu , Gibson Susan I.
Published: November 2005

We have established Catharanthus roseus hairy root cultures transgenic for the rol ABC genes from TL‐DNA of the agropine‐type Agrobacterium rhizogenes strain A4. The rol ABC hairy root lines exhibit a wild‐type hairy root syndrome in terms of growth and morphology on solid medium. However, they differ from wild‐type hairy root lines in that they more frequently have excellent adaptability to liquid medium and do not appear to form calli during cultivation. Moreover, they do not produce detectable levels of mannopine and agropine which, in contrast, are often synthesized abundantly in wild‐type hairy root lines. The absence of these opines does not appear to cause the rol ABC lines to have higher levels of terpenoid indole alkaloids than wild‐type hairy root lines. Unlike wild‐type lines, rol ABC lines produce very similar levels of total alkaloids despite wide variations in individual alkaloid contents. This work demonstrates that the three genes rol ABC are sufficient to induce high‐quality hairy roots in Catharanthus roseus. © 2005 Wiley Periodicals, Inc.
2C4, a monoclonal antibody against HER2, disrupts the HER kinase signaling pathway and inhibits ovarian carcinoma cell growth
Authors: Takai Noriyuki , Jain Anjali , Kawamata Norihiko , Popoviciu Laura M. , Said Jonathan W. , Whittaker Sadie , Miyakawa Isao , Agus David B. , Koeffler H. Phillip
Published: November 2005

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) is overexpressed in 25–30% of ovarian carcinoma cases and a correlation between increased HER2 expression and decreased survival has been demonstrated. HER2 is a ligand‐less member of the HER family that functions as the preferred coreceptor for epidermal growth factor receptor (EGFR), HER3, and HER4.

METHODS

An approach was developed to target HER2's role as a coreceptor using a monoclonal antibody, 2C4, which sterically hinders HER2's recruitment into a functional HER complex.

RESULTS

HER2 was robustly expressed in all eight ovarian carcinoma cell lines; expression of EGFR and HER3 was variable. Even though four of the eight cell lines responded to EGF, 2C4 antibody moderately inhibited in vitro proliferation of only two cell lines (OVCA433 and SK‐OV‐3). Furthermore, ligand‐stimulated p‐MAPK expression was inhibited by 2C4 only in these two cell lines after exposure to EGF. Immunoprecipitation and eTag analysis revealed that OVCA433 expressed heterodimers of EGFR/HER2, and these heterodimers were disrupted after treatment with 2C4, whereas OVCA432 cells did not have these heterodimers. In murine xenograft experiments, the in vivo growth of OVCA433, but not of OVCA432, ovarian carcinoma cells was significantly inhibited by 2C4 treatment of the mice.

CONCLUSION

2C4 is able to disrupt the HER signaling pathway and inhibit the in vitro and in vivo growth of ovarian carcinoma cell lines. The response appears limited to lines in which HER2 heterodimers were able to transduce proliferative signals. Our findings suggest a strong rationale to conduct clinical trials of 2C4 in a subset of patients with ovarian tumors. Cancer 2005. © 2005 American Cancer Society.
Topotecan as a radiosensitizer in the treatment of children with malignant diffuse brainstem gliomas
Authors: Bernier‐Chastagner Valerie , Grill Jacques , Doz Francois , Bracard Serge , Gentet Jean Claude , Marie‐Cardine A. , Luporsi E. , Margueritte G. , Lejars O. , Laithier V. , Mechinaud F. , Millot F. , Kalifa C. , Chastagner Pascal
Published: November 2005

BACKGROUND

The current Phase II study was conducted to evaluate the survival and toxicity observed in children with newly diagnosed brainstem gliomas who were treated with the daily radiotherapy with topotecan used as a radiosensitizer.

METHODS

Eligible patients were those ages 3–18 years with previously untreated tumors arising in the pons diagnosed within the previous 6 months. Histologic confirmation was not mandatory provided that the clinical and magnetic resonance imaging findings were typical for a diffusely infiltrating brainstem lesion. Treatment was comprised of a 6‐week course of topotecan administered intravenously at a dose of 0.4 mg/m2/day over 30 minutes within 1 hour before irradiation. Radiotherapy was comprised of a once‐daily treatment of 1.8 grays (Gy) per fraction to a total dose of 54 Gy.

RESULTS

Thirty‐two patients were included in the current study between August 2000 and October 2002. All patients completed the combined treatment in accordance with the treatment design. Only partial responses were observed, occurring in 40% of the patients. The 9‐month and 12‐month survival rates were 34.4% ± 8% and 25.5% ± 8%, respectively. The median duration of survival for these 32 patients was 8.3 months. An intratumoral cystic/necrotic change was observed in five patients, with clinical impairment noted in two patients. One intratumoral hemorrhage occurred during radiotherapy, and was associated with transitory neurologic impairment.

CONCLUSIONS

The findings of the current study regarding newly diagnosed brainstem glioma patients treated with topotecan given as a radiosensitizing agent did not reproduce the encouraging results obtained in preclinical studies. Therefore, the concomitant combination of topotecan and radiotherapy at this schedule and these doses cannot be recommended for the treatment of patients with brainstem gliomas. Cancer 2005. © 2005 American Cancer Society.
A control volume finite element method for three‐dimensional NAPL groundwater contamination
Authors: Letniowski F. W. , Forsyth P. A.
Published: November 2005

A three‐dimensional control volume finite element method is developed for NAPL groundwater contamination problems. Tetrahedral elements are formed by decomposing deformed blocks. The decomposition is carried out in such a way as to minimize the size of the negative transmissibilities. Negative transmissibilities produce non‐physical discrete fluid flow paths and can cause oscillatory behaviour in the Newton iteration. Example results are presented for a three‐dimensional NAPL contamination scenario using typical geophysical data.
Grey‐body surface radiation coupled with conduction and convection for general geometries
Authors: Engelman Michael , Jamnia Mohammad‐Ali
Published: November 2005

This paper presents a numerical technique for the simulation of the effects of grey‐diffuse surface radiation on the temperature field of fluid flows using FIDAP, a general purpose incompressible, viscous fluid code. The radiating surface relationships assume a non‐participating medium, constant surface temperature and heat fluxes at the discretized elemental level.

The technique involves the decoupling of energy and radiation exchange equations. A concept of macrosurfaces, each containing a number of radiating boundary surfaces, is introduced. These boundary macroelements then carry the information from the radiating boundary into the fluid regime. A number of simulations illustrating the algorithm are presented.
A decomposed Crouzeix‐Raviart element for the finite element solution of the Navier‐Stokes equation
Authors: Bertrand F. H. , Hayes R. E. , Tanguy P. A.
Published: November 2005

A methodology for the decomposition of the Crouzeix‐Raviart finite element into six linear subelements is described. The resulting element is shown to satisfy the Brezzi‐Babuška compatibility condition. The error bounds are also established. A comparison in accuracy between this and the standard Crouzeix‐Raviart element is presented for driven cavity flows. Other results include the execution time for the DCR element and the Crouzeix‐Raviart element along with both analytical and numerical integration. It is shown that the decomposed element results in shorter execution times with only marginal changes in accuracy.
A local adaptive grid procedure for incompressible flows with multigridding and equidistribution concepts
Authors: Moukalled F. , Acharya S.
Published: November 2005

An adaptive grid solution procedure is developed for incompressible flow problems in which grid refinement based on an equidistribution law is performed in high‐error‐estimate regions that are flagged from a preliminary coarse grid solution. Solutions on the locally refined and equidistributed meshes are obtained using boundary conditions interpolated from the preliminary coarse grid solution, and solutions on both the refined and coarse grid regions are successively improved using a multigrid approach. For this purpose, suitable correction terms for the coarse grid equations are derived for all variables in the flagged regions. This procedure with Local Adaptation, Multigridding and Equidistribution (LAME) concepts is applied to various flow problems to demonstrate the accuracy improvements obtained using this method.
Turbulent flow calculations using unstructured and adaptive meshes
Authors: Mavriplis Dimitri J.
Published: November 2005

A method of efficiently computing turbulent compressible flow over complex two‐dimensional configurations is presented. The method makes use of fully unstructured meshes throughout the entire flow field, thus enabling the treatment of arbitrarily complex geometries and the use of adaptive meshing techniques throughout both viscous and inviscid regions of the flow field. Mesh generation is based on a locally mapped Delaunay technique in order to generate unstructured meshes with highly stretched elements in the viscous regions. The flow equations are discretized using a finite element Navier‐Stokes solver, and rapid convergence to steady state is achieved using an unstructured multigrid algorithm. Turbulence modelling is performed using an inexpensive algebraic model, implemented for use on unstructured and adaptive meshes. Compressible turbulent flow solutions about multiple‐element aerofoil geometries are computed and compared with experimental data.