bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Molecular Weight Heparin in the Treatment of Venous and Arterial Thromboses in the Premature Infant
Authors: Michaels Lisa A. , Gurian Michael , Hegyi Thomas , Drachtman Richard A.
Published: November 2004

Objective. Thrombosis in the preterm newborn is a growing problem, a result of improved survival of the smallest and sickest infants. Treatment with low molecular weight heparin (LMWH) has potential advantages, including predictable pharmacokinetics, subcutaneous administration, and minimal monitoring. However, studies with LMWH in term infants demonstrate the need for higher doses as compared with older children and adults. Physiologic differences suggest the need for gestational age–appropriate treatment strategies. Because of the relatively small numbers of infants affected each year, large-scale prospective studies have not been feasible. With the goal of establishing treatment guidelines within our own institution, we reviewed retrospectively our experience with LMWH for the treatment of thrombosis in the preterm infant.

Methods. Medical and pharmacy records of the intensive care nursery were used to identify preterm infants with venous and arterial thrombosis. Chart documentation, orders, pharmacy records, and radiologic studies were used to develop a retrospective database to assess efficacy and safety of the treatment. Main outcome measures were the dose of LMWH required for therapeutic levels, anti-factor Xa levels achieved, bleeding complications, resolution of thrombosis, additional thromboembolic events, and death from all causes.

Results. Ten preterm infants (mean gestational age: 26 weeks) who were treated with LMWH were identified. Mean patient weight at diagnosis of thrombosis was 1215 g (range: 565–1950 g). All 10 patients had either a current or recent history of a central venous or arterial catheter. Mean starting dose of enoxaparin was 1.25 mg/kg per 12 hours (range: 0.8–2 mg/kg). Therapeutic anti-factor Xa levels were achieved in only 5 patients. Mean time to therapeutic range was 33 days (range: 14–63 days). The mean dose of enoxaparin required to achieve therapeutic levels was 2.27 mg/kg per 12 hours (dose range: 2.0–3.5 mg/kg per 12 hours). Clot resolution was observed in all but 2 patients, both of whom died of complications of their thromboembolic events. No bleeding events that necessitated a change in treatment strategy occurred.

Conclusions. Higher doses of LMWH are required in the preterm infant as compared with the healthy term neonate. Once therapeutic levels are achieved, continued regular monitoring and dose adjustments are required to maintain anticoagulation in therapeutic range.
Blood Pressure at 6 Years of Age After Prenatal Exposure to Betamethasone: Follow-up Results of a Randomized, Controlled Trial
Authors: Dalziel Stuart R. , Liang Allen , Parag Varsha , Rodgers Anthony , Harding Jane E.
Published: November 2004

Objective. To determine whether prenatal exposure to betamethasone for the prevention of neonatal respiratory distress syndrome (RDS) alters blood pressure in childhood.

Design. Prospective follow-up study of a randomized, double-blind, placebo-controlled trial.

Setting. National Women's Hospital (Auckland, New Zealand).

Participants. Two hundred twenty-three 6-year-old children of mothers who presented with unplanned premature labor and took part in a randomized, controlled trial of prenatal betamethasone therapy for the prevention of neonatal RDS.

Intervention. Mothers received 2 doses of betamethasone (12 mg) or placebo, administered through intramuscular injection, 24 hours apart.

Main Outcome Measures. Systolic and diastolic blood pressure at 6 years of age.

Results. Children exposed prenatally to betamethasone (n = 121) did not differ in systolic or diastolic blood pressure from children exposed to placebo (n = 102) (mean difference: systolic: −1.6 mm Hg; 95% confidence interval: −4.1 to 0.8 mm Hg; diastolic: −0.3 mm Hg; 95% confidence interval: −2.5 to 1.8 mm Hg).

Conclusion. Prenatal exposure to betamethasone for prevention of neonatal RDS does not alter blood pressure at 6 years of age.
The Internet—A New Medical Problem or Invaluable Ally?
Authors: Spitzer Alan R.
Published: November 2004

The public’s increasing use of the Internet as a personal medical consultant poses new problems and special opportunities for the practicing physician. This article outlines how the Internet is already changing medical practice and how physicians can begin to use this resource to an advantage in their daily medical practice.
Intussusception in Early Childhood: A Cohort Study of 1.7 Million Children
Authors: Kølsen Fischer Thea , Bihrmann Kristine , Perch Michael , Koch Anders , Wohlfahrt Jan , Kåre Mølbak , Melbye Mads
Published: November 2004

Objective. To describe incidence and temporal trends of intussusceptions in Danish children during 1980 to 2001.

Methods. A population-based cohort study was conducted of 1.67 million children who were younger than 5 years during 1980 to 2001 and were followed up for 6.66 million person-years. The Danish National Patient Registry was used to identify cases of intussusception in the cohort. Age-specific incidence rates were main outcome measure.

Results. A total of 1814 cases of intussusception among children who were younger than 5 years were reported from 1980 to 2001. The incidence rate remained fairly constant during 1980 to 1990 but decreased by 55% (95% confidence interval: 43%–65%) from 1990 to 2001. The reduction was most pronounced among children aged 3 to 5 months.

Conclusions. The incidence of intussusception among Danish children declined significantly during the 1990s, particularly among infants 3 to 5 months of age.
Pediatric Crohn's Disease and Growth Retardation: The Role of Genotype, Phenotype, and Disease Severity
Authors: Wine Eytan , Reif Shimon S. , Leshinsky-Silver Esther , Weiss Batya , Shaoul Ron R. , Shamir Raanan , Wasserman Dror , Lerner Aaron , Boaz Mona , Levine Arie
Published: November 2004

Background. Delayed growth is a well-established feature of pediatric Crohn's disease. Several factors have been shown to affect growth, including disease location, severity, and treatment. The recently discovered NOD2 gene has been correlated to ileal location of Crohn's disease and subsequently could affect growth through the resulting phenotype or as an independent risk factor. The aim of our study was to determine if growth retardation is affected by genotype independently of disease location or severity.

Methods. Genotyping for 3 NOD2 single-nucleotide polymorphisms was performed in 93 patients with detailed growth records. Parameters including disease location, disease severity, and NOD 2 genotype and their effect on z scores for height and weight at disease onset and during follow-up were analyzed.

Results. NOD2 mutations were correlated with ileal location but not with disease severity or growth retardation. Ileal involvement was significantly associated with height retardation at disease onset and the lowest z score during follow-up. Use of steroids affected weight but not height. Regression models for growth variables revealed that the strongest association with impaired growth is with disease severity (weight- and height-failure odds ratios: 6.17 and 4.52, respectively).

Conclusions. Severity of disease is correlated with growth failure for both height and weight. Location of disease is a weaker predictor of disordered growth and is correlated with growth retardation but not growth failure. The NOD2 genotype was not correlated with growth retardation or growth failure.
Thimerosal-Containing Vaccines and Autistic Spectrum Disorder: A Critical Review of Published Original Data
Authors: Parker Sarah K. , Schwartz Benjamin , Todd James , Pickering Larry K.
Published: November 2004

Objective. The issue of thimerosal-containing vaccines as a possible cause of autistic spectrum disorders (ASD) and neurodevelopmental disorders (NDDs) has been a controversial topic since 1999. Although most practitioners are familiar with the controversy, many are not familiar with the type or quality of evidence in published articles that have addressed this issue. To assess the quality of evidence assessing a potential association between thimerosal-containing vaccines and autism and evaluate whether that evidence suggests accepting or rejecting the hypothesis, we systematically reviewed published articles that report original data pertinent to the potential association between thimerosal-containing vaccines and ASD/NDDs.

Methods. Articles for analysis were identified in the National Library of Medicine's Medline database using a PubMed search of the English-language literature for articles published between 1966 and 2004, using keywords thimerosal, thiomersal, mercury, methylmercury, or ethylmercury alone and combined with keywords autistic disorder, autistic spectrum disorder, and neurodevelopment. In addition, we used the “related links” option in PubMed and reviewed the reference sections in the identified articles. All original articles that evaluated an association between thimerosal-containing vaccines and ASD/NDDs or pharmacokinetics of ethylmercury in vaccines were included.

Results. Twelve publications that met the selection criteria were identified by the literature search: 10 epidemiologic studies and 2 pharmacokinetic studies of ethylmercury. The design and quality of the studies showed significant variation. The preponderance of epidemiologic evidence does not support an association between thimerosal-containing vaccines and ASD. Epidemiologic studies that support an association are of poor quality and cannot be interpreted. Pharmacokinetic studies suggest that the half-life of ethylmercury is significantly shorter when compared with methylmercury.

Conclusions. Studies do not demonstrate a link between thimerosal-containing vaccines and ASD, and the pharmacokinetics of ethylmercury make such an association less likely. Epidemiologic studies that support a link demonstrated significant design flaws that invalidate their conclusions. Evidence does not support a change in the standard of practice with regard to administration of thimerosal-containing vaccines in areas of the world where they are used.
Uncomplicated Intraventricular Hemorrhage Is Followed by Reduced Cortical Volume at Near-Term Age
Authors: Vasileiadis George T. , Gelman Neil , Han Victor K.M. , Williams Lori-Anne , Mann Rupinder , Bureau Yves , Thompson R. Terry
Published: November 2004

Background. Intraventricular hemorrhage (IVH) is the most common brain injury among premature infants. Neonates with IVH are at greater risk of impaired neurodevelopmental outcomes, compared with those without IVH. IVH causes destruction of the germinal matrix and glial precursor cells, with possible effects on cortical development.

Objective. To investigate cortical development after uncomplicated IVH (with no parenchymal involvement and no posthemorrhagic hydrocephalus). We hypothesized that uncomplicated IVH would be followed by reduced cortical volume among premature infants at near-term age.

Methods. A prospective cohort study was conducted, with preset selection criteria. Infants with small-for-gestational age birth weight, congenital abnormalities or brain malformations, metabolic disorders, recurrent sepsis, or necrotizing enterocolitis were excluded. Also, infants with posthemorrhagic hydrocephalus, parenchymal involvement of hemorrhage, cystic periventricular leukomalacia, or persistent ventriculomegaly were excluded, on the basis of routine serial ultrasonographic assessments. Three-dimensional images were acquired for 23 infants at near-term age, with 3-T magnetic resonance imaging and a magnetization-prepared rapid gradient echo sequence. Image analysis and segmentation of the cerebrum in different tissue types were based on signal contrast and anatomic localization. The cortical gray matter (CGM), subcortical gray matter, white matter, and intraventricular cerebrospinal fluid volumes of 12 infants with uncomplicated IVH were compared with those of 11 infants without IVH, using multivariate analysis of variance.

Results. The multivariate analysis of variance for the regional brain volumes in the 2 groups indicated significance (Wilks' λ = 0.546). The CGM volume was significantly reduced in the IVH group (no-IVH group: 122 ± 12.9 mL; IVH group: 102 ± 14.6 mL; F = 13.218). This finding remained significant after testing for possible confounding factors and adjustment for size differences between the infants (F = 9.415). There was no difference in the volumes of subcortical gray matter, white matter, and cerebrospinal fluid.

Conclusions. This is the first study to document impaired cortical development after uncomplicated IVH. The impairment was demonstrated by a 16% reduction in cerebral CGM volume at near-term age. The finding supports concerns regarding possible glial precursor cell loss after germinal matrix IVH, but its clinical significance is still unclear. The alteration in brain development demonstrated in this report supports closer neurodevelopmental follow-up monitoring of preterm infants with uncomplicated IVH.
Brain-Type Natriuretic Peptide in the Diagnosis and Management of Persistent Pulmonary Hypertension of the Newborn
Authors: Reynolds Eric W. , Ellington Jeff G. , Vranicar Mark , Bada Henrietta S.
Published: November 2004

Objective. The diagnosis of persistent pulmonary hypertension (PPHN) can often be difficult to make, especially in a clinical setting in which pediatric echocardiography is not readily available. A noninvasive test that could differentiate PPHN from other cardiorespiratory disease would be very useful in the early management of the disease, because it would allow rapid identification of those infants at greatest risk of requiring the services of a level 3 nursery. Brain-type natriuretic peptide (BNP) is an endogenous peptide hormone secreted by the cardiac ventricles in response to increased wall stress and related ventricular filling pressures. The purpose of this study was to determine if BNP levels are elevated in newborns with PPHN and therefore may be used as a marker for differentiating PPHN from other forms of respiratory disease during the early newborn period.

Method. We used a prospective cohort design with 3 groups. One group was diagnosed with PPHN by clinical and echocardiographic criteria (PPHN group: n = 15). The second group had been diagnosed with respiratory disease; however, PPHN had been ruled out by having no evidence of elevated pulmonary pressure by echocardiography (RD group: n = 17). The third group had no respiratory disease and was breathing room air (RA group: n = 15). BNP levels were measured with a point-of-care fluorescence immunoassay at various time intervals between birth and 150 hours of life.

Results. There were no differences between groups for birth weight, gestational age, gender, race, Apgar scores at 1 minute, or age at time of initial blood sampling. Initial BNP levels (pg/mL) were elevated in the PPHN group relative to both the RA and RD groups (median [25%, 75%]: PPHN group = 1610 [1128, 1745]; RD group = 132 [76, 327]; RA group = 248 [127, 395]). There was no difference in the initial BNP level between the RA and RD groups. BNP levels remained elevated in the PPHN group over both groups for the first 4 days of life. BNP levels correlated with the gradient of the tricuspid regurgitation jet and with the ratio of tricuspid regurgitation jet gradient to mean blood pressure. BNP levels were not affected by administration of dopamine or dobutamine. BNP weakly correlated with the oxygenation index but not with the alveolar-arterial oxygenation gradient.

Conclusions. Our findings indicate that BNP levels are elevated in infants with PPHN but not in infants with other forms of respiratory distress not associated with PPHN. Elevated BNP levels in term or near-term infants with respiratory distress should increase the suspicion of PPHN. Serial determination may also be helpful in monitoring the clinical course of such infants.
A Double-Blind, Randomized, Placebo-Controlled Trial of Acupuncture for the Treatment of Childhood Persistent Allergic Rhinitis
Authors: Ng Daniel K. , Chow Pok-yu , Ming Shun-pei , Hong Siu-hung , Lau Sunny , Tse Debbie , Kwong Wilson K. , Wong Mui-fong , Wong Wilfred H. , Fu Yu-ming , Kwok Ka-li , Li Handong , Ho Jackson C.
Published: November 2004

Objective. To compare active acupuncture with sham acupuncture for the treatment of persistent allergic rhinitis among children.

Methods. Subjects with persistent allergic rhinitis were recruited from the pediatric outpatient clinic. They were randomized to receive either active acupuncture or sham acupuncture. Main outcome measures included daily rhinitis scores, symptom-free days, visual analog scale scores for immediate effects of acupuncture, daily relief medication scores, blood eosinophil counts, serum IgE levels, nasal eosinophil counts, patients' and parents' preferences for treatment modalities, and adverse effects.

Results. Eighty-five patients were recruited from the pediatric outpatient clinic at Kwong Wah Hospital, in Hong Kong. Thirteen patients withdrew before randomization; 35 patients (mean age: 11.7 ± 3.2 years) were randomized to receive active acupuncture for 8 weeks, and 37 patients (mean age: 11 ± 3.8 years) were randomized to receive sham acupuncture for 8 weeks. Acupuncture was performed twice per week for both groups. Both the assessing pediatricians and the patients were blinded. There were significantly lower daily rhinitis scores and more symptom-free days for the group receiving active acupuncture, during both the treatment and follow-up periods. The visual analog scale scores for immediate improvement after acupuncture were also significantly better for the active acupuncture group. There was no significant difference in the following outcome measures between the active and sham acupuncture groups: daily relief medication scores, blood eosinophil counts, serum IgE levels, and nasal eosinophil counts, except for the IgE levels before and 2 months after acupuncture in the sham acupuncture group. No severe adverse effects were encountered. Numbness, headache, and dizziness were found in both the active and sham acupuncture groups, with no difference in incidence, and the effects were self-limiting.

Conclusions. This study showed that active acupuncture was more effective than sham acupuncture in decreasing the symptom scores for persistent allergic rhinitis and increasing the symptom-free days. No serious adverse effect was identified. A large-scale study is required to confirm the safety of acupuncture for children.
A New Complication of Stem Cell Transplantation: Measles Inclusion Body Encephalitis
Authors: Freeman Alexandra F. , Jacobsohn David A. , Shulman Stanford T. , Bellini William J. , Jaggi Preeti , Leon Guillermo de , Keating Gesina F. , Kim Francine , Pachman Lauren M. , Kletzel Morris , Duerst Reggie E.
Published: November 2004

Measles inclusion body encephalitis (MIBE) is a disease of the immunocompromised host and typically occurs within 1 year of acute measles infection or vaccination. We report a 13-year-old boy who had chronic granulomatous disease and presented 38 days after stem cell transplantation with afebrile focal seizures that progressed despite multiple anticonvulsants. After an extensive diagnostic evaluation, brain biopsy was performed, revealing numerous intranuclear inclusion bodies consistent with paramyxovirus nucleocapsids. Measles studies including reverse transcriptase-polymerase chain reaction and viral growth confirmed measles virus, genotype D3. Immunohistochemistry was positive for measles nucleoprotein. Despite intravenous ribavirin therapy, the patient died. MIBE has not been described in stem cell recipients but is a disease of immunocompromised hosts and typically occurs within 1 year of measles infection, exposure, or vaccination. Our case is unusual as neither the patient nor the stem cell donor had apparent recent measles exposure or vaccination, and neither had recent travel to measles-endemic regions. The patient had an erythematous rash several weeks before the neurologic symptoms; however, skin biopsy was consistent with graft-versus-host disease, and immunohistochemistry studies for measles nucleoprotein were negative. As measles genotype D3 has not been seen in areas where the child lived since his early childhood, the possibility of an unusually long latency period between initial measles infection and MIBE is raised. In addition, this case demonstrates the utility of brain biopsy in the diagnosis of encephalitis of unknown cause in the immunocompromised host.
Classifying Recommendations for Clinical Practice Guidelines
Authors:   Steering Committee on Quality Improvement and Management
Published: November 2004

Clinical practice guidelines are intended to improve the quality of clinical care by reducing inappropriate variations, producing optimal outcomes for patients, minimizing harm, and promoting cost-effective practices. This statement proposes an explicit classification of recommendations for clinical practice guidelines of the American Academy of Pediatrics (AAP) to promote communication among guideline developers, implementers, and other users of guideline knowledge, to improve consistency, and to facilitate user understanding. The statement describes 3 sequential activities in developing evidence-based clinical practice guidelines and related policies: 1) determination of the aggregate evidence quality in support of a proposed recommendation; 2) evaluation of the anticipated balance between benefits and harms when the recommendation is carried out; and 3) designation of recommendation strength. An individual policy can be reported as a “strong recommendation,” “recommendation,” “option,” or “no recommendation.” Use of this classification is intended to improve consistency and increase the transparency of the guideline-development process, facilitate understanding of AAP clinical practice guidelines, and enhance both the utility and credibility of AAP clinical practice guidelines.
Prenatal Screening and Diagnosis for Pediatricians
Authors: Cunniff Christopher ,   and Committee on Genetics
Published: November 2004

This Technical Report was retired January 2011.

The pediatrician who cares for a child with a birth defect or genetic disorder may be in the best position to alert the family to the possibility of a recurrence of the same or similar problems in future offspring. The family may wish to know about and may benefit from methods that convert probability statements about recurrence risks into more precise knowledge about a specific abnormality in the fetus. The pediatrician also may be called on to discuss abnormal prenatal test results as a way of understanding the risks and complications that the newborn infant may face. Along with the increase in knowledge brought about by the sequencing of the human genome, there has been an increase in the technical capabilities for diagnosing many chromosome abnormalities, genetic disorders, and isolated birth defects in the prenatal period. The purpose of this report is to update the pediatrician about indications for prenatal diagnosis, current techniques used for prenatal diagnosis, and the status of maternal screenings for detection of fetal abnormalities.
Relief of Pain and Anxiety in Pediatric Patients in Emergency Medical Systems
Authors: Zempsky William T. , Cravero Joseph P. ,   Committee on Pediatric Emergency Medicine, and Section on Anesthesiology and Pain Medicine
Published: November 2004

Whether a component of a disease process, the result of acute injury, or a product of a diagnostic or therapeutic procedure, pain should be relieved and stress should be decreased for pediatric patients. Control of pain and stress for children who enter into the emergency medical system, from the prehospital arena to the emergency department, is a vital component of emergency care. Any barriers that prevent appropriate and timely administration of analgesia to the child who requires emergency medical treatment should be eliminated. Although more research and innovation are needed, every opportunity should be taken to use available methods of pain control. A systematic approach to pain management and anxiolysis, including staff education and protocol development, can have a positive effect on providing comfort to children in the emergency setting.
Exploitation of Localized Surface Plasmon Resonance
Authors: Hutter E. , Fendler J. H.
Published: November 2004

Recent advances in the exploitation of localized surface plasmons (charge density oscillations confined to metallic nanoparticles and nanostructures) in nanoscale optics and photonics, as well as in the construction of sensors and biosensors, are reviewed here. In particular, subsequent to brief surveys of the most‐commonly used methods of preparation and arraying of materials with localized surface plasmon resonance (LSPR), and of the optical manifestations of LSPR, attention will be focused on the exploitation of metallic nanostructures as waveguides; as optical transmission, information storage, and nanophotonic devices; as switches; as resonant light scatterers (employed in the different near‐field scanning optical microscopies); and finally as sensors and biosensors.
Localization of MRX82: A new nonsyndromic X‐linked mental retardation locus to Xq24‐q25 in a Basque family
Authors: Martínez Francisco , Martínez‐Garay Isabel , Oltra Silvestre , Moltó María Dolores , Orellana Carmen , Monfort Sandra , Prieto Félix , Tejada Isabel
Published: November 2004

Clinical and molecular studies are reported on a Basque family (MRX82) with nonsyndromic X‐linked mental retardation (XLMR) in five affected males. A total of 38 microsatellite markers were typed. The XLMR locus has been linked to DXS8067, DXS1001, DXS425, DXS7877, and DXS1183 with a maximum LOD score of 2.4. The haplotype studies and multipoint linkage analysis suggest a localization of the MRX82 locus to an interval of 7.6 Mb defined by markers DXS6805 and DXS7346, in Xq24 and Xq25, respectively. No gene contained in this interval has been so far associated with nonsyndromic mental retardation, except for GRIA3, disrupted by a balanced translocation in a female patient with bipolar affective disorder and mental retardation. However, the search for mutations of this gene did not showed a pathogenic mutation in the present family. Given that there are other eight MRX families overlapping this interval, none of them with known mutation, we conclude that at least one new gene responsible for nonsyndromic mental retardation is located in this region. © 2004 Wiley‐Liss, Inc.
De novo interstitial direct duplication of Xq21.1q25 associated with skewed X‐inactivation pattern
Authors: Tachdjian G. , Aboura A. , Benkhalifa M. , Creveaux I. , Foix‐Hélias L. , Gadisseux J.F. , Boespflug‐Tanguy O. , Mohammed M. , Labrune P.
Published: November 2004

Genotype‐phenotype correlation in women with an abnormal phenotype associated with a duplication of the long arm of the X chromosome remains unclear. We report on prenatal diagnosis and follow‐up of a girl with an Xq duplication and dysmorphic features. The abnormal phenotype included growth retardation, hypotonia, and nystagmus. In order to improve the resolution of the cytogenetic analysis, we used both conventional and array‐based comparative genomic hybridization to perform a global molecular cytogenetic analysis of the genome. These molecular cytogenetic analyses showed a direct duplication Xq21.1 → q25 without other chromosomal abnormalities. This duplication was originating from the paternal X chromosome. Moreover, a skewed X‐inactivation pattern was observed leading to a partial functional disomy of the chromosomal region Xq21.1q25. This report and review of the literature suggest that functional disomy for chromosome X could explain the abnormal phenotype. In prenatal diagnosis, this can have implication for patient management and genetic counseling. © 2004 Wiley‐Liss, Inc.
Morphology of mitochondrial permeability transition: Morphometric volumetry in apoptotic cells
Authors: Sesso Antonio , Marques Márcia M. , Monteiro Maria M.T. , Schumacher Robert I. , Colquhoun Alison , Belizário José , Konno Sérgio N. , Felix Tahis B. , Botelho Luis A.A. , Santos Vanessa Z.C. , Da Silva Guilherme R. , Higuchi Maria De L. , Kawakami Joyce T.
Published: November 2004

Here we report on the mitochondrial permeability transition (MPT), which refers to the morphology of mitochondria whose inner membrane has lost its selective permeability. In all types of apoptotic cells so far examined, we found outer mitochondrial membranes that had been ruptured. These mitochondria present a swollen matrix covered by an inner membrane herniating into the cytoplasm through the breached outer membrane. Similarly ruptured outer mitochondrial membranes have been reported in studies on mitochondrial fractions induced to undergo MPT, carried out by others. Our observations were made on five types of rat tissue cells and six different cultured cell lines in the early stages of apoptosis. Samples from the cell lines HL‐60, HeLa, WEHI‐164, and a special batch of PC‐12 cells were subjected to various apoptogenic agents and analyzed morphometrically. Nonapoptotic companion cells with unaltered nuclear structure (CUNS) were also analyzed. The mitochondrial volume in μm3 and the volume fraction of the cytoplasm occupied by mitochondria in cells with typical nuclear signs of apoptosis and also in CUNS were evaluated. The volume of the mitochondria with ruptured membrane represents at least 69% (47–89%) of the total mitochondrial volume of the apoptotic cells. Thus, a considerable fraction of the cellular mitochondrial mass is or was in the state of permeability transition and probably involved in enhancement of the apoptotic program. In all samples, a fraction of the cells with normal nuclei possessed mitochondria with breached outer membranes as described above. In these cells, MPT occurred before the appearance of the typical nuclear phenotype of the apoptotic cells. © 2004 Wiley‐Liss, Inc.
Reduced birth defects caused by maternal immune stimulation in methylnitrosourea‐exposed mice: Association with placental improvement
Authors: Prater Mary Renee , Zimmerman Kurt Lee , Ward Daniel Lee , Holladay Steven David
Published: November 2004

BACKGROUND

Methylnitrosourea (MNU) is a potent carcinogen and teratogen that is associated with central nervous system, craniofacial, skeletal, ocular, and appendicular birth defects following transplacental exposure at critical time points during development, and preliminary studies have suggested that nonspecific maternal immunostimulation may offer protection against development of these birth defects.

METHODS

Our study examined morphologic alterations in fetal limb and digital development and placental integrity following maternal exposure to MNU on GD 9 in CD‐1 mice, and characterized the improvement in placental integrity and abrogation of fetal defects following maternal immune stimulation with interferon‐gamma (IFN‐γ) on GD 7.

RESULTS

Fetal limbs were significantly shortened (p < 0.0001) and incidence of limb and digital defects (syndactyly, polydactyly, oligodactyly, clubbing, and webbing) was dramatically increased following midgestational maternal MNU exposure. Maternal immune stimulation with IFN‐γ on GD 7 lessened incidence of fetal limb shortening and maldevelopment on GD 12 and 14. Further, disruption of placental spongiotrophoblast integrity, increased cell death in placental trophoblasts with increased intercellular spaces in the spongiotrophoblast layer and minimal inflammation, and increased loss of fetal labyrinthine endothelial cells from MNU‐exposed dams suggested that MNU‐induced placental breakdown may contribute to fetal limb and digital maldevelopment. MNU + IFN‐γ was associated with diminished cell death within all layers of the placenta, especially in the labyrinthine layer.

CONCLUSIONS

These data verify improved distal limb development in MNU‐exposed mice as a result of maternal IFN‐γ administration, and suggest a link between placental integrity and proper fetal development. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Further characterization of the genetic defect of the Bent tail mouse, a mouse model for human neural tube defects
Authors: Klootwijk Riko , Schijvenaars Mascha M.V.A.P. , Mariman Edwin C.M. , Franke Barbara
Published: November 2004

BACKGROUND

Neural tube defects (NTDs) are congenital malformations arising mostly from incomplete neural tube closure during early embryogenesis. Most NTDs in humans have a complex etiology, with involvement of both genetic and environmental factors. More than 100 mouse models for human neural tube defects exist; Bent tail is one of them. The mouse mutant is caused by a submicroscopic deletion on Xq that completely encompasses the Zic3 gene.

METHODS

We searched the ENSEMBL database for other genes/transcribed sequences in the Bent tail deletion in addition to Zic3, which we confirmed by PCR analysis.

RESULTS

In our study, we show that the Bent tail deletion is at least 300 kb in size, encompassing a processed pseudogene and a number of expressed sequence tags in addition to Zic3. Although more research is needed to clarify the identity and function of the deleted transcripts, most of them are expressed during embryonic development and might therefore contribute to the phenotype of the Bent tail mouse.

CONCLUSIONS

This study presents the first evidence for the fact that the Bent tail allele is not merely a Zic3 knockout allele, as has been previously suggested. Birth Defects Research (Part A), 2004. Published 2004 Wiley‐Liss, Inc.
Molecular genetic analysis of human homologs of Caenorhabditis elegans mab‐21‐like 1 gene in patients with neural tube defects
Authors: Merello Elisa , De Marco Patrizia , Moroni Anna , Raso Alessandro , Calevo Maria Grazia , Consalez G. Giacomo , Cama Armando , Capra Valeria
Published: November 2004

BACKGROUND

Neural tube defects (NTDs) are complex embryological malformations, affecting 1 in 1,000 live births. Antisense studies have implicated murine Mab21 genes as having an important role in neural tube development. We investigated whether MAB21L1/L2 genes could be involved in the aetiology of NTDs.

METHODS

Denaturing HPLC (DHPLC) analysis of MAB21 genes was performed in 116 NTD cases. A case‐control approach was used to test if the two single nucleotide polymorphisms (SNPs) of the MAB21L1 gene might be associated with increased NTD risk.

RESULTS

No pathological variants of MAB21L1/L2 genes were identified by DHPLC analysis. Case‐control studies demonstrated that the two SNPs (CAG triplets in 5′UTR; A→C in 3′UTR) in the MAB21L1 gene are unlikely to be directly responsible for myelomeningocele.

CONCLUSIONS

We suggest that MAB21 genes are unlikely to have substantial impact on NTDs. These preliminary findings will need to be investigated in larger samples before firm conclusions can be made. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Polymyxin B–lipid interactions in Langmuir–Blodgett monolayers of Escherichia coli lipids: A thermodynamic and atomic force microscopy study
Authors: Clausell Adrià , Busquets M. Antonia , Pujol Montserrat , Alsina Asunción , Cajal Yolanda
Published: November 2004

The dramatically increased frequency of antibiotic resistance has led to intensive efforts towards developing new families of antibiotics. Membrane‐active antibiotic peptides such as polymyxin B (PxB) hold promise as the next generation of antibiotics, since they rarely spur the evolution of resistance. At low concentrations in the membrane, PxB forms vesicle–vesicle contacts and induces lipid exchange without leakage or fusion, a phenomenon that can explain its specificity towards Gram‐negative bacteria by contact formation between the two phospholipids interfaces in the periplasmatic space. In this work, the interaction of PxB and the nonantibiotic derivative polymyxin B nonapeptide (PxB–NP) with monolayers of Escherichia coli membrane lipids (ECL) has been studied by thermodynamic and structural methods. PxB inserts itself into ECL monolayers as a conformation that forms intermembrane contacts with vesicles injected underneath, and induces lipid exchange when the monolayer surface pressure is set at 32 mN/m (membrane equivalence pressure) or net transfer vesicle‐to‐monolayer at lower surface pressures. Thermodynamic analysis of the compression isotherms of mixed monolayers indicates that PxB inserts into the monolayer with an expansion of the mean molecular area, implying that peptide and lipids form nonideal mixtures. At low concentrations, corresponding to the membrane–membrane contact form of PxB, the mixed monolayers present positive excess energy values (ΔG), and atomic force microscopy (AFM) imaging reveals structures of ∼120‐nm diameter that protrude from the lipid surface ∼0.7 nm. At concentrations of PxB above 4 mol %, thermodynamic analysis gives a very high ΔG, corresponding to nonfavorable interactions, and AFM images show round structures of 20–30nm diameter. PxB–NP behaves in a totally different way, in agreement with its inability to form vesicle–vesicle contacts and its lack of antibiotic effect. These results are discussed in the light of the mechanism of action of PxB on the membrane of Gram‐negative bacteria. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Transient production of recombinant proteins by Chinese hamster ovary cells using polyethyleneimine/DNA complexes in combination with microtubule disrupting anti‐mitotic agents
Authors: Tait Andrew S. , Brown Catherine J. , Galbraith Douglas J. , Hines Michael J. , Hoare Mike , Birch John R. , James David C.
Published: November 2004

We have developed a simple and robust transient expression system utilizing the 25 kDa branched cationic polymer polyethylenimine (PEI) as a vehicle to deliver plasmid DNA into suspension‐adapted Chinese hamster ovary cells synchronized in G2/M phase of the cell cycle by anti‐mitotic microtubule disrupting agents. The PEI‐mediated transfection process was optimized with respect to PEI nitrogen to DNA phosphate molar ratio and the plasmid DNA mass to cell ratio using a reporter construct encoding firefly luciferase. Optimal production of luciferase was observed at a PEI N to DNA P ratio of 10:1 and 5 μg DNA 106 cells−1. To manipulate transgene expression at mitosis, we arrested cells in G2/M phase of the cell cycle using the microtubule depolymerizing agent nocodazole. Using secreted human alkaline phosphatase (SEAP) and enhanced green fluorescent protein (eGFP) as reporters we showed that continued inclusion of nocodazole in cell culture medium significantly increased both transfection efficiency and reporter protein production. In the presence of nocodazole, greater than 90% of cells were eGFP positive 24 h post‐transfection and qSEAP was increased almost fivefold, doubling total SEAP production. Under optimal conditions for PEI‐mediated transfection, transient production of a recombinant chimeric IgG4 encoded on a single vector was enhanced twofold by nocodazole, a final yield of approximately 5 μg mL−1 achieved at an initial viable cell density of 1 × 106 cells mL−1. The glycosylation of the recombinant antibody at Asn297 was not significantly affected by nocodazole during transient production by this method. © 2004 Wiley Periodicals, Inc.
Increased megakaryopoiesis in cultures of CD34‐enriched cord blood cells maintained at 39°C
Authors: Proulx Chantal , Dupuis Nicolas , St‐Amour Isabelle , Boyer Lucie , Lemieux Réal
Published: November 2004

Based on previous evidence suggesting positive effects of fever on in vivo hematopoiesis, we tested the effect of hyperthermia on megakaryopoiesis (MK) in ex vivo cultures of CD34‐enriched cord blood (CB) cells. The cells were cultured at 37°C or 39°C for 14 days in cytokine conditions optimized for megakaryocyte development and analyzed periodically. Compared to 37°C, the cultures maintained at 39°C produced significantly more (up to 10‐fold) total cells, myeloid and MK progenitors, and total MKs, and showed accelerated and enhanced MK maturation with increased yields of proplatelets and platelets. This observation could facilitate clinical applications requiring ex vivo expansion of hematopoietic cells. © 2004 Wiley Periodicals, Inc.
Characterization of the metabolic burden on Escherichia coli DH1 cells imposed by the presence of a plasmid containing a gene therapy sequence
Authors: Rozkov A. , Avignone‐Rossa C.A. , Ertl P.F. , Jones P. , O'Kennedy R.D. , Smith J.J. , Dale J.W. , Bushell M.E.
Published: November 2004

The presence of a plasmid, containing gene sequences for DNA immunotherapy that are not expressed in microbial culture, imposed a degradation in bioreactor performance in cultures of the host
E. coli strain. Significant decreases in growth rate (24%) and biomass yield (7%) and a corresponding increase in overflow metabolism were observed in a strain containing a therapeutic sequence (a hepatitis B antigen under the control of a CMV promotor). The observed increase in overflow metabolism was incorporated into a Metabolic Flux Analysis (MFA) model (as acetate secretion). Metabolic flux analysis revealed an increase in TCA cycle flux, consistent with an increased respiration rate observed in plasmid‐containing cells. These effects are thought to result from increased ATP synthesis requirements (24%) arising from the expression of the Kanr plasmid marker gene whose product accounted for 18% of the cell protein of the plasmid‐containing strain. These factors will necessitate significantly higher aeration and agitation rates or lower nutrient feed rates in high‐density cultures than would be expected for plasmid‐free cultures. © 2004 Wiley Periodicals, Inc.
Novel Rhodium‐Catalyzed Reaction of Thiazolidine Derivatives with Carbodiimides
Authors: Zhou Hai‐Bing , Dong Chune , Alper Howard
Published: November 2004

A new, simple, and regioselective synthesis of thiazolidinimine derivatives based on the rhodium‐catalyzed reaction of readily available thiazolidines with carbodiimides is described. This methodology provides direct access to a large variety of thiazolidinimine derivatives, possibly via a novel regiospecific insertion of carbodiimides into one of two ring carbon–nitrogen bonds, as well as a metal‐catalyzed imine elimination process.
Nuclearity Controlled Cyanide‐Bridged Bimetallic CrIII–MnII Compounds: Synthesis, Crystal Structures, Magnetic Properties and Theoretical Calculations
Authors: Toma Luminita , Lescouëzec Rodrigue , Vaissermann Jacqueline , Delgado Fernando S. , Ruiz‐Pérez Catalina , Carrasco Rosa , Cano Juan , Lloret Francesc , Julve Miguel
Published: November 2004

The preparation, X‐ray crystallography and magnetic investigation of the compounds PPh4[Cr(bipy)(CN)4]⋅2 CH3CN⋅H2O (1) (mononuclear), [{Cr(bipy)(CN)4}2Mn(H2O)4]⋅4 H2O (2) (trinuclear), [{Cr(bipy)(CN)4}2Mn(H2O)2] (3) (chain) and [{Cr(bipy)(CN)4}2Mn(H2O)]⋅H2O⋅ CH3CN (4) (double chain) [bipy=2,2′‐bipyridine; PPh4+=tetraphenylphosphonium] are described herein. The [Cr(bipy)(CN)4]− unit act either as a monodentate (2) or bis‐monodentate (3) ligand toward the manganese atom through one (2) or two (3) of its four cyanide groups. The manganese atom is six‐coordinate with two (2) or four (3) cyanide nitrogens and four (2) or two (3) water molecules building a distorted octahedral environment. In 4, two chains of 3 are pillared through interchain Mn‐N‐C‐Cr links which replace one of the two trans‐coordinated water molecules at the manganese atom to afford a double chain structure where bis‐ and tris‐monodenate coordination modes of [Cr(bipy)(CN)4]− coexist. The magnetic properties of 1–4 were investigated in the temperature range 1.9–300 K. A Curie law behaviour for a magnetically isolated spin quartet is observed for 1. A significant antiferromagnetic interaction between CrIII and MnII through the single cyanide bridge [J=−6.2 cm−1, the Hamiltonian being defined as Ĥ=−J(ŜCr(1)⋅ŜMn+ŜCr(2)⋅ŜMn)] occurs in 2 leading to a low‐lying spin doublet which is fully populated at T <5 K. A metamagnetic behaviour is observed for 3 and 4 [the values of the critical field Hc being ca. 3000 (3) and 1500 Oe (4)] which is associated to the occurrence of weak interchain antiferromagnetic interactions between ferrimagnetic ${{\rm Cr}{{{\rm III}\hfill \atop 2\hfill}}}$ MnII chains. The analysis of the exchange pathways in 2–4 through DFT type calculations together with the magnetic bevaviour simulation using the quantum Monte Carlo methodology provided a good understanding of their magnetic properties.
High‐Throughput Heterogeneous Catalytic Science
Authors: Hendershot Reed J. , Snively Christopher M. , Lauterbach Jochen
Published: November 2004

High‐throughput experimentation in heterogeneous catalysis has recently experienced nearly exponential growth. Initial qualitative screening has evolved into quantitative high‐throughput experimentation, characterization, and analysis. This allows high‐throughput catalysis now to rise above simple screening to the level of fundamental understanding of reaction mechanisms, which will lead on a faster path to the Holy Grail of catalysis: rational catalyst design.
Palladium‐Catalyzed Asymmetric Allylic Alkylation of Ketone Enolates
Authors: Trost Barry M. , Schroeder Gretchen M.
Published: November 2004

Palladium‐catalyzed asymmetric allylic alkylation of nonstabilized ketone enolates to generate quaternary centers has been achieved in excellent yield and enantioselectivity. Optimized conditions consist of performing the reaction in the presence of two equivalents of LDA as base, one equivalent of trimethytin chloride as a Lewis acid, 1,2‐dimethoxyethane as the solvent, and a catalytic amount of a chiral palladium complex formed from π‐allyl palladium chloride dimer 3 and cyclohexyldiamine derived chiral ligand 4. Linearly substituted, acyclic 1,3‐dialkyl substituted, and unsubstituted allylic carbonates function well as electrophiles. A variety of α‐tetralones, cyclohexanones, and cyclopentanones can be employed as nucleophiles. The absolute configuration generated is consistent with the current model in which steric factors control stereofacial differentiation. The quaternary substituted products available by this method are versatile substrates for further elaboration.
Multiple Refocusing in NMR Spectroscopy: Compensation of Pulse Imperfections by Scalar Couplings
Authors: Dittmer Jens , Bodenhausen Geoffrey
Published: November 2004

When applying multiple refocusing pulses to characterize the cross‐correlated relaxation of heteronuclear multiple quantum coherence 2NxHx in biomolecules, the unavoidable effects of pulse imperfections are compensated by the scalar couplings between nitrogen atoms and protons. The experiment, which is useful as a tool for studying slow internal dynamics of biomolecules, greatly benefits from this compensation. The underlying effect is a manifestation of an interchange between three noncommuting components of the density operator. One perturbing Hamiltonian is counteracted by another, which leads to a nearly complete suppression of the perturbation. The effect proves to be an example of a hitherto unknown phenomenon in NMR spectroscopy.
Molecular Complexes of Organometallic Molecules with Noble Gases: The Rotational Spectrum of Dimethylsilane–Argon
Authors: Ottaviani Paolo , Melandri Sonia , Caminati Walther , Banser Deike , Schnell Melanie , Grabow Jens‐Uwe
Published: November 2004

The rotational spectrum of the molecular complex dimethylsilane–argon was investigated by free‐jet absorption millimeter‐wave and molecular‐beam Fourier transform spectroscopy. The absolute energy minimum corresponds to a conformation in which the argon atom lies in the plane of symmetry of dimethylsilane, perpendicular to the CSiC plane. The distance of Ar from the center of mass of dimethylsilane is 3.90 Å, and the Ar atom is tilted 14° away from the Si atom. The zero‐point dissociation energy was estimated from the centrifugal distortion constant DJ to be 2.2 kJ mol−1. Small splitting, due to tunneling of the Ar atom and internal rotation of the two methyl groups, was observed, measured, and used to determine the potential energy surface for these motions.