bluuebunny/crossref_metadata_2025 huggingface dataset:
Membrane-Bound Diiron Carboxylate Proteins
Authors: Berthold Deborah A. , Stenmark Pål
Published: May 2003

Four proteins have been identified recently as diiron carboxylate proteins on the basis of conservation of six amino acids (four carboxylate residues and two histidines) constituting an iron-binding motif. Unlike previously identified proteins with this motif, biochemical studies indicate that each of these proteins is membrane bound, although homology modeling rules out a transmembrane mode of binding. Therefore, the predicted structure of each protein [the alternative oxidase (AOX), the plastid terminal oxidase (PTOX), the diiron 5-demethoxyquinone hydroxylase (DMQ hydroxylase), and the aerobic Mg-protoporphyrin IX monomethylester hydroxylase (MME hydroxylase)] is that of a protein bound monotopically to one leaflet of the membrane bilayer. Three of these enzymes utilize a quinol substrate, with two oxidizing the quinol (AOX and PTOX) and one hydroxylating it (DMQ hydroxylase). MME hydroxylase is involved in synthesis of the isocyclic ring of chlorophyll. Two enzymes are involved in respiration (AOX and, indirectly, the diiron DMQ hydroxylase through ubiquinone biosynthesis) and two in photosynthesis, through their roles in carotenoid and chlorophyll biosynthesis (PTOX and MME hydroxylase, respectively). We discuss what is known about each enzyme as well as our expectations based on their identification as interfacially bound proteins with a diiron carboxylate active site.
From Bacterial Glycogen to Starch: Understanding the Biogenesis of the Plant Starch Granule
Authors: Ball Steven G. , Morell Matthew K.
Published: May 2003

Plants, green algae, and cyanobacteria synthesize storage polysaccharides by a similar ADPglucose-based pathway. Plant starch metabolism can be distinguished from that of bacterial glycogen by the presence of multiple forms of enzyme activities for each step of the pathway. This multiplicity does not coincide with any functional redundancy, as each form has seemingly acquired a distinctive and conserved role in starch metabolism. Comparisons of phenotypes generated by debranching enzyme-defective mutants in Escherichia coli and plants suggest that enzymes previously thought to be involved in polysaccharide degradation have been recruited during evolution to serve a particular purpose in starch biosynthesis. Speculations have been made that link this recruitment to the appearance of semicrystalline starch in photosynthetic eukaryotes. Besides the common core pathway, other enzymes of malto-oligosaccharide metabolism are required for normal starch metabolism. However, according to the genetic and physiological system under study, these enzymes may have acquired distinctive roles.
Plant Peroxiredoxins
Authors: Dietz Karl-Josef
Published: May 2003

Peroxiredoxins (Prxs) are abundant low-efficiency peroxidases located in distinct cell compartments including the chloroplast and mitochondrion. They are grouped into four clans based on their structural and biochemical properties. The catalytic center contains a cysteinyl residue that reduces diverse peroxides and is regenerated via intramolecular or intermolecular thiol-disulfide-reactions and finally by electron donors such as thioredoxins and glutaredoxins. Prxs show a complex regulation by endogenous and environmental stimuli at both the transcript and protein levels. In addition to their role in antioxidant defense in photosynthesis, respiration, and stress response, they may also be involved in modulating redox signaling during development and adaptation.
Lignin Biosynthesis
Authors: Boerjan Wout , Ralph John , Baucher Marie
Published: May 2003

The lignin biosynthetic pathway has been studied for more than a century but has undergone major revisions over the past decade. Significant progress has been made in cloning new genes by genetic and combined bioinformatics and biochemistry approaches. In vitro enzymatic assays and detailed analyses of mutants and transgenic plants altered in the expression of lignin biosynthesis genes have provided a solid basis for redrawing the monolignol biosynthetic pathway, and structural analyses have shown that plant cell walls can tolerate large variations in lignin content and structure. In some cases, the potential value for agriculture of transgenic plants with modified lignin structure has been demonstrated. This review presents a current picture of monolignol biosynthesis, polymerization, and lignin structure.
Understanding the Functions of Plant Disease Resistance Proteins
Authors: Martin Gregory B. , Bogdanove Adam J. , Sessa Guido
Published: May 2003

Many disease resistance (R) proteins of plants detect the presence of disease-causing bacteria, viruses, or fungi by recognizing specific pathogen effector molecules that are produced during the infection process. Effectors are often pathogen proteins that probably evolved to subvert various host processes for promotion of the pathogen life cycle. Five classes of effector-specific R proteins are known, and their sequences suggest roles in both effector recognition and signal transduction. Although some R proteins may act as primary receptors of pathogen effector proteins, most appear to play indirect roles in this process. The functions of various R proteins require phosphorylation, protein degradation, or specific localization within the host cell. Some signaling components are shared by many R gene pathways whereas others appear to be pathway specific. New technologies arising from the genomics and proteomics revolution will greatly expand our ability to investigate the role of R proteins in plant disease resistance.
Cryptochrome Structure and Signal Transduction
Authors: Lin Chentao , Shalitin Dror
Published: May 2003

Cryptochromes are photosensory receptors mediating light regulation of growth and development in plants. Since the isolation of the Arabidopsis CRY1 gene in 1993, cryptochromes have been found in every multicellular eukaryote examined. Most plant cryptochromes have a chromophore-binding domain that shares similar structure with DNA photolyase, and a carboxyl terminal extension that contains a DQXVP-acidic-STAES (DAS) domain conserved from moss, to fern, to angiosperm. In Arabidopsis, cryptochromes are nuclear proteins that mediate light control of stem elongation, leaf expansion, photoperiodic flowering, and the circadian clock. Cryptochromes may act by interacting with proteins such as phytochromes, COP1, and clock proteins, or/and chromatin and DNA. Recent studies suggest that cryptochromes undergo a blue light–dependent phosphorylation that affects the conformation, intermolecular interactions, physiological activities, and protein abundance of the photoreceptors.
Genetic Variants of TNF-α, IL-1β, IL-4 Receptor α-Chain, IL-6 and IL-10 Genes Are Not Risk Factors for Sepsis in Low-Birth-Weight Infants
Authors: Treszl András , Kocsis István , Szathmári Miklós , Schuler Ágnes , Héninger Erika , Tulassay Tivadar , Vásárhelyi Barna
Published: May 2003

The amount of inflammatory cytokines is a major determinant for the development of sepsis in very-low-birth-weight (VLBW) neonates. We investigated whether variants of tumor necrosis factor-α, interleukin (IL)-1β, IL-4 receptor α-chain, IL-6 and IL-10 genes, associated with altered cytokine production, might influence the risk and complications of sepsis in VLBW infants. We determined the presence of these genetic variants in dried blood samples of 33 septic, 35 infected and 35 healthy VLBW neonates by PCR and RFLP methods and analyzed their association with the risk and complications of sepsis. The frequencies of genetic variants did not differ in uninfected and in infected infants with or without sepsis. Moreover, none of the studied complications was associated with carrier state of any of genetic variants. Four of the 5 septic neonates with disseminated intravascular coagulation, however, carried simultaneously the variants of IL-1β and IL-10 genes. We concluded that these genetic polymorphisms do not influence the risk and course of sepsis in VLBW neonates.
Lack of Prognostic Significance of Early Elevated Serum Uric Acid Levels in Low Birthweight Infants
Authors: Sysyn Gregory D. , Rozycki Henry J.
Published: May 2003

This study examined the utility of serum uric acid concentrations in the first day of life to identify infants with severe brain injury (grade III or IV intraventricular hemorrhage and/or periventricular leukomalacia). The serum uric acid concentrations in infants with severe brain injury were compared to those without. Severe brain injury was assessed in 151 infants with birthweight ≤1,251 g admitted before 24 h of life. The risk of severe brain injury was related to 5-min Apgar scores (odds ratio 0.79, CI 0.63–0.98, p < 0.05) and seizures in the first day of life (odds ratio 4.44, CI 1.004–19.66, p < 0.05), but the mean uric acid levels did not differ between those with and without severe brain injury [5.11 ± 1.88 mg/dl (303.9 ± 111.8 µmol/l) vs. 5.77 ± 2.13 mg/dl (343.2 ± 126.7 µmol/l), p = 0.200]. Uric acid levels were related to serum creatinine (p < 0.001), time of uric acid sample (p < 0.001), maternal hypertension (p < 0.001), and base deficit (p = 0.032). Of the 80 infants seen in neurodevelopmental follow-up at a median 11 months postconceptional age, uric acid concentrations did not differ between the abnormal (n = 20) and normal subjects [5.38 ± 1.72 mg/dl (320.0 ± 102.3 µmol/l) vs. 6.02 ± 2.55 mg/dl (358.1 ± 151.8 µmol/l), p = 0.197]. Uric acid may not be a useful early marker for premature infants with severe brain injury.
Dual Perinatal and Developmental Expression of the Small Heat Shock Proteins αB-Crystallin and Hsp27 in Different Tissues of the Developing Piglet
Authors: Tallot P. , Grongnet J.F. , David J.C.
Published: May 2003

Expression of the two closely related heat shock proteins (HSPs), αB-crystallin and Hsp27, was studied in various tissues of the developing pig. Expression of αB-crystallin was maximum in the lens while expression of Hsp27 was absent. In non-lenticular tissues, both proteins were strongly expressed in heart and muscle. Increases in αB-crystallin expression were observed in brain, liver and kidney while Hsp27 was increased in kidney at later stages. Relatively constant expression was found in heart while a decrease in both stress proteins was observed between 28 days and 6 months in skeletal muscle. In the different parts of the gastrointestinal tract, increased expression of αB-crystallin was seen following birth and weaning while increased expression of Hsp27 was restricted to weaning. These results are discussed in terms of the protective effects of HSPs during stressful events in the different tissues of the developing pig.
Gastric Emptying in Rats following Administration of a Range of Different Fats Measured as Acetaminophen Concentration in Plasma
Authors: Porsgaard Trine , Straarup Ellen Marie , Høy Carl-Erik
Published: May 2003

Aim: To investigate the gastric emptying upon administration of ten different fats in order to determine whether major differences in fatty acid profiles resulted in differences in gastric emptying. Methods: Gastric emptying was measured as the appearance of acetaminophen in plasma which represents an indirect measure of gastric emptying. Emulsified fats with added acetaminophen were fed by gavage to rats, and the plasma concentration of acetaminophen was followed for 3 h by repeated blood sampling from the carotid artery. The fats administered included rapeseed, corn, and fish oils, lard, and cocoa butter as well as different structured lipids containing decanoic acid (10:0) and long-chain n-3 polyunsaturated fatty acids of marine origin. Overall, these fats had wide variations in fatty acid compositions and triacylglycerol structures. Results: No statistically significant differences were observed in gastric emptying between the groups fed the different fats, except for the emptying of tridecanoin (tri-10:0) that was statistically significantly slower than that of randomized oil, cocoa butter, and rapeseed oil (p < 0.05). The slower emptying of tri-10:0 could be caused by a lower caloric intake of this fat as compared with the other fats, because similar weights of fat were administered. Conclusion: The gastric emptying of fat was not influenced by fatty acid composition and triacylglycerol structure of the fats administered.
Effect of Feeding Maize/Legume Mixtures on Biochemical Indices in Rats
Authors: Obatolu Veronica A. , Ketiku A. , Adebowale E.A.
Published: May 2003

Protein-energy malnutrition is one of the major public health problems in developing countries of the world due to prevailing socio-economic problems. This study aimed to observe the effect of formulated complementary blends on biochemical parameters of rats. Extruded complementary blends from maize fortified with cowpea or soybean at a level of 35% and 25% respectively were fed to 4 groups of rats for 28 days. Similarly, 3 other groups of rats were placed on casein, non-protein or rat pellet diet. Biochemical analysis was done on blood samples of the rats. Results from previous studies show the protein content of the formulated diets to range from 15.75% in UMC to 17.24% in MMS. Significantly (p < 0.05) lower WBC, Hb, MCHC, total protein, albumin and globulin values were recorded for the rats fed a non-protein diet (NP). The serum AST level was 75.5, 71.2, 63.2, 51.0, 60.5 and 55.7, respectively, for rats on casein, rat pellet, MMS, UMS, MMC and UMC (list of abbreviations is shown in the appendix) diets. Alkaline phosphatase was significantly (p < 0.05) higher in soybean-based diets while cholesterol was lowest in rats fed the non-protein diet (NP). The value obtained for serum electrolyte concentration in the rats fed NP compared well with rats on other diets but, however, had a significantly (p < 0.05) higher serum sodium value. These results confirm that the experimental diets supported growth, as shown in a previous study, and had no harmful consequence.
Evaluation of Virtual Reality Bronchoscopy as a Learning and Assessment Tool
Authors: Moorthy K. , Smith S. , Brown T. , Bann S. , Darzi A.
Published: May 2003

Background: Conventional training in bronchoscopy involves a trainee performing on a real patient under supervision. This method of training is not only expensive, but there is also potential for increased patient discomfort. Simulators permit the acquisition of necessary technical skills required for the procedure. Virtual reality (VR) has been an integral part of training in aviation, and the application of this technology in medical training needs to be evaluated. Objective: This study was conducted to evaluate the efficacy of a VR bronchoscopy simulator as a learning and assessment tool. Methods: The bronchoscopic simulator (HT Medical Systems, Maryland, USA) is a VR computer programme. The simulator has the ability to assess competence by a set of parameters, which formed the data for the study. Nine novices without previous bronchoscopic experience formed the study group (group 1). Nine experienced bronchoscopists having performed between 200 and 1,000 bronchoscopies formed the other group (group 2). We assessed the efficacy of the system as a learning tool by studying whether there was a significant difference between the first and subsequent sessions of the subjects from group 1 and by comparing the performance of the two groups. Statistical analysis was done using the Mann-Whitney U test and the Wilcoxon signed ranks test. Results: There was a significant difference in performance between the first attempt of group 1 and the performance of the experts in terms of percentage of segments visualised and number of wall collisions and the economy of performance. Among the subjects from group 1, there was a significant improvement in percentage of segments visualised by the third attempt (p = 0.04), in the economy of performance by the sixth attempt (0.008) and in the number of wall collisions by the sixth attempt (0.024). When each attempt of the novices was compared with the performance of group 2, the significance in the difference of the percentage of segments studied (p = 0.09) and the economy of performance disappeared by the third attempt (0.06), while the difference in the number of wall collisions disappeared by the fifth attempt (p = 0.06). Conclusions: This study has been able to establish the face, construct and content validity of the simulator and the potential for it to be an effective training tool.
The Effects of Posteroventral Pallidotomy on Balance Function in Patients with Parkinson’s Disease
Authors: Westerberg B.D. , Roberson J.B. , Stach B.A. , Silverberg G.D. , Heit G.
Published: May 2003

Parkinson’s disease is a chronic, progressive neurodegenerative disorder resulting from dopaminergic cell loss in the pars compacta of the substantia nigra. Conventional treatment of Parkinson’s disease consists of pharmacological replacement of dopamine. A treatment alternative, posteroventral pallidotomy (PVP), has been used for medically intractable stages of the disease. The purpose of this study was to evaluate the effects of PVP on balance function, as measured by dynamic posturography, in patients with medically intractable Parkinson’s disease. Five subjects were studied within 2 days prior to and within 6 months following PVP. Pretreatment abnormalities were found in vestibular, visual, and somatosensory processing in balance function. Posteroventral pallidotomy resulted in improvement in vestibular compensation of posture in some patients, which may be at least partially due to an improvement in latencies to respond to changes in stance. Dynamic posturography is an effective tool in the evaluation of balance and posture in patients with advanced Parkinson’s disease.
Intractable Epilepsy and Olfactory Bulb Hamartoma
Authors: McEvoy Andrew W. , Bartolucci Marcello , Revesz Thomas , Harkness William
Published: May 2003

The objective of this case report is to demonstrate that a benign tumour arising solely from the olfactory bulb can act as a primary epileptic focus and to illustrate the difficulty in making a preoperative diagnosis of pathological lesions in this area. The case of a 29-year-old male with intractable epilepsy is presented. Radiological imaging demonstrated a conspicuous, calcified lesion in the mesial inferior frontal lobe. Electroclinical findings confirmed this to be the epileptogenic zone. Surgery and subsequent histology surprisingly revealed this focal lesion to be a benign hamartoma arising solely from the olfactory bulb. Resection resulted in seizure resolution. Tumours of the olfactory apparatus are extremely rare, but can present with epilepsy.
Stereotactic Radiosurgery for Type 2 Neurofibromatosis Acoustic Neuromas: Patient Selection and Tumour Size
Authors: Rowe Jeremy G. , Radatz Matthias , Walton Lee , Kemeny Andras A.
Published: May 2003

Acoustic neuromas which are secondary to type 2 neurofibromatosis (NF2) respond less well to radiosurgery than unilateral sporadic disease. To refine the selection of these patients, a regression analysis was performed examining the response to radiosurgery of 114 NF2 tumours. The major determinant of outcome was tumour volume (p < 0.001). Calculating sensitivity and specificity values for different tumour volume limits gives a sensitivity value of 0.96 for a volume limit of 10 cm3. This suggests that the size constraints that apply to the radiosurgical management of NF2 acoustic neuromas differ and are more restricted than those which are accepted for acoustic neuromas in general.
Multivariate Analysis of Risk Factors for Development of Duodenal Ulcer in Helicobacter pylori-Infected Patients
Authors: Regula Jaroslaw , Hennig Ewa , Burzykowski Tomasz , Orlowska Janina , Przytulski Krzysztof , Polkowski Marcin , Dziurkowska-Marek Anna , Marek Tomasz , Nowak Andrzej , Butruk Eugeniusz , Ostrowski Jerzy
Published: May 2003

Background: Although Helicobacter pylori is a significant etiologic factor of peptic ulcer disease, it remains unknown why ulcers develop only in the minority of infected individuals. Aim: The aim of this cross-sectional study was to evaluate the association between the presence of duodenal ulcer in H. pylori-infected patients and different risk factors. Methods: A total of 122 H. pylori-infected patients were enrolled; 79 had duodenal ulcer and 43 gastritis. Univariate analysis was conducted using either Fisher’s exact test or exact Cochrane-Armitage trend test. In multivariate analysis the logistic model was used. Results: Univariate analysis indicated six factors (male sex, smoking, antral H. pylori density, cagA presence in antrum, and vacA s1a presence in antrum and corpus). Four factors (sex, smoking-alcohol index, H. pylori density index, and cagA index) were found to be significant in multivariate analysis. The best model predicting duodenal ulcer included male sex, smoking, presence of H. pylori on histopathology in antrum and cagA presence in corpus. Conclusion: Although several risk factors were significantly associated with duodenal ulcer, we failed in the identification of either a single risk factor or a set of factors that can unequivocally differentiate patients with ulcer from those with gastritis.
Leaflet Escape in a New Bileaflet Mechanical Valve
Authors: Bottio Tomaso , Casarotto Dino , Thiene Gaetano , Caprili Luca , Angelini Annalisa , Gerosa Gino
Published: May 2003

Background—

Leaflet escape is a mode of structural valve failure for mechanical prostheses. This complication previously has been reported for both monoleaflet and bileaflet valve models. We report 2 leaflet escape occurrences observed in 2 patients who underwent valve replacement with a TRI Technologies valve prosthesis.

Methods and Results—

At the University of Padua, between November 2000 and February 2002, 36 TRI Technologies valve prostheses (26 aortic and 10 mitral) were implanted in 34 patients (12 women and 22 men) with a mean age of 59.9±10.3 years (range, 30 to 75 years). There were 5 deaths: 3 in hospital, 1 early after discharge, and 1 late. Two patients experienced a catastrophic prosthetic leaflet escape; the first patient was a 52-year-old man who died 10 days after aortic valve and ascending aorta replacement, and the second was a 58-year-old man who underwent a successful emergency reoperation 20 months after mitral valve replacement. Examination of the explanted prostheses showed in both cases a leaflet escape caused by a leaflet’s pivoting system fracture. Prophylactic replacement was then successfully accomplished so far in 12 patients, without evidence of structural valve failure in any of them. Among other significant postoperative complications, we observed 3 major thromboembolisms, 1 hemorrhage, and 1 paravalvular leak.

Conclusion—

These catastrophes prompted us to interrupt the implantation program, and they cast a shadow on the durability of the TRI Technologies valve prosthesis because of its high risk of structural failure.
Electrical Resynchronization
Authors: Dubin Anne M. , Feinstein Jeffrey A. , Reddy V. Mohan , Hanley Frank L. , Van Hare George F. , Rosenthal David N.
Published: May 2003

Background—

Many patients with congenital heart disease develop right ventricular (RV) failure due to anatomy and prior therapy. RV problems may include right bundle-branch block (RBBB), volume loading, and chamber enlargement. Because the failing RV may have regional dyskinesis, we hypothesized that resynchronization therapy might augment its performance.

Methods and Results—

We studied 7 patients with RV dysfunction and RBBB, using a predefined pacing protocol. QRS duration, cardiac index (CI), and RV dP/dt were measured in 4 different pacing states. Atrioventricular pacing improved CI and RV dP/dt
max
and decreased QRS duration as compared with atrial pacing or sinus rhythm.

Conclusions—

Atrioventricular pacing in patients with RBBB and RV dysfunction augments RV and systemic performance. RV resynchronization is a promising novel therapy for patients with RV failure.
Phase II Trial of ZD1839 in Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck
Authors: Cohen Ezra E. W. , Rosen Fred , Stadler Walter M. , Recant Wendy , Stenson Kerstin , Huo Dezheng , Vokes Everett E.
Published: May 2003

Purpose: The epidermal growth factor receptor (EGFR) is a mediator of squamous cell carcinoma of the head and neck (SCCHN) development. ZD1839 is an orally active, selective EGFR tyrosine kinase inhibitor. This phase II study sought to explore the activity, toxicity, and pharmacodynamics of ZD1839 in SCCHN.

Patients and Methods: Patients with recurrent or metastatic SCCHN were enrolled through the University of Chicago Phase II Consortium. Patients were allowed no more than one prior therapy for recurrent or metastatic disease and were treated with single-agent ZD1839 500 mg/d. Patient tumor biopsies were obtained and stained immunohistochemically for EGFR, extracellular signal-regulated kinase 1 (ERK1), and phosphorylated ERK1 (p-ERK). Study end points included response rate, time to progression, median survival, and inhibition of p-ERK.

Results: Fifty-two patients were enrolled (40 male and 12 female) with a median age of 59 years (range, 34 to 84 years). Fourteen patients received ZD1839 through a feeding tube. Half the cohort received ZD1839 as second-line therapy. Forty-seven patients were assessable for response, with an observed response rate of 10.6% and a disease control rate of 53%. Median time to progression and survival were 3.4 and 8.1 months, respectively. The only grade 3 toxicity encountered was diarrhea in three patients. Performance status and development of skin toxicity were found to be strong predictors of response, progression, and survival. Ten biopsy samples were assessable and revealed no significant change in EGFR or p-ERK expression with ZD1839 therapy.

Conclusion: ZD1839 has single-agent activity and is well tolerated in refractory SCCHN. In contrast to other reports, development of skin toxicity was a statistically significant predictor of response and improved outcome.
Male patient with non‐mosaic deleted Y‐chromosome and clinical features of Turner syndrome
Authors: Graham B.H. , Bacino C.A.
Published: May 2003

Turner syndrome is hypothesized to result from haplo‐insufficency of a gene or perhaps multiple genes present on the sex chromosomes; however, the frequent association of mosaicism with deletions of the sex chromosomes prevents establishing useful genotype/phenotype correlations. In this clinical report, we present a male with a de novo, non‐mosaic deletion of the Y‐chromosome. The phenotype of this patient is unlike any similar cases previously reported in the literature. This patient exhibits many classical clinical features of Turner syndrome including short stature, characteristic facial anomalies, and webbed neck with low posterior hairline, aortic valve abnormality, and hearing impairment. Detailed molecular characterization of this deleted Y‐chromosome could provide important information towards establishing genotype/phenotype correlations in Turner syndrome. © 2003 Wiley‐Liss, Inc.
Zhu H, Barber R, Shaw GM, Lammer EJ Finnell RH. 2003. Is Sonic hedgehog (SHH) a candidate gene for spina bifida? A pilot study. Am J Med Genet 117A:87–88.
Authors: Zhu Huiping , Barber Robert , Shaw Gary M. , Lammer Edward J. , Finnell Richard H.
Published: May 2003

The original article to which this erratum refers was published in the American Journal of Medical Genetics (2003) 117A:87–88
Ethanol consumption and DRD2 gene TaqI a polymorphism among socially drinking males
Authors: Hallikainen Tero , Hietala J. , Kauhanen J. , Pohjalainen T. , Syvälahti E. , Salonen J.T. , Tiihonen J.
Published: May 2003

The dopaminergic system in the human brain is thought to play a major role in the development of alcohol consumption habits and alcoholism. It has been reported that homozygous D2−/− knock‐out mice lacking D2 receptors consume about 50% to 60% less ethanol than wild‐type D2+/+ mice, and heterozygous mice have an intermediate level of alcohol consumption. The DRD2 gene TaqI A polymorphism has been suggested to associate with a low D2 receptor density in post mortem and in vivo measurements. Numerous association studies on this polymorphism and alcoholism have shown most controversial results. We studied whether DRD2 TaqI A genotype affects alcohol consumption in an ethnically homogenous, representative sample of 1,019 Finnish Caucasian males. After excluding the abstainers from the study, the self‐reported alcohol consumption among the remaining 884 non‐abstainers was compared in the TaqI A genotype groups (A1/A1, A1/A2, A2/A2). The alcohol consumption of the homozygous A1/A1 group was about 30% lower than in A1/A2 group, and 40% lower than in A2/A2 group (P = 0.042 and 0.041 in a sociodemographic variable‐adjusted multivariate model). The results indicate an association between DRD2 genotype and alcohol consumption habits in humans. These results in the large sample of non‐alcoholic males are also opposite to some previous findings on the higher A1 allele frequency among alcoholic populations. © 2003 Wiley‐Liss, Inc.
Food fortification with folic acid and twinning among California infants
Authors: Shaw Gary M. , Carmichael Suzan L. , Nelson Verne , Selvin Steve , Schaffer Donna M.
Published: May 2003

This study sought to determine whether a change in twinning prevalence was associated with mandatory folic acid fortification. As of January 1998, it became mandatory in the United States that grain products be fortified with folic acid. The effectiveness of this fortification for neural tube defects has been explored, but other possible implications of fortification has not. We computed the prevalence of twinning among more than 2.5 million California births occurring from 1990 to 1999. The prevalence of twin births in California increased over the last decade with increases observed among most maternal race/ethnic, age, and parity groupings. Unadjusted prevalence measures did not reveal substantial increases in twinning prevalence among these groupings after the fortification period relative to the period immediately preceding it. Analyses that simultaneously adjusted for age, parity, race/ethnicity, sexes of twin pair (as a measure of zygosity), year of birth, and fortification period also did not reveal an association between fortification and twinning. Our results do not suggest a change in twinning prevalence associated with folic acid fortification of the US food supply among women delivering in California. © 2003 Wiley‐Liss, Inc.
Recent developments in bisdiborane chemistry: BCB, BCCB, BCCB and BCCB compounds
Authors: Dembitsky Valery M. , Abu Ali Hijazi , Srebnik Morris
Published: May 2003

An overview of the development of new strategies in organic synthesis with a minimum of chemical steps is becoming increasingly necessary for the efficient assembly of complex molecular structures. Therefore, the combination of multiple reactions in a single operation represents a particularly efficient approach. Among these strategies, the synthesis and reactivity of bisdiboranes has never been reviewed although its popularity for the synthesis of complex architectural molecules has been steadily increasing during the last decade. This review is intended to highlight the use of partly geminated boranes (BCB), and also bisdiborane reagents (BCCB, BCCB, BCCB). Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis, structure and reactivity of cationic base‐stabilized gallyleneiron complexes
Authors: Ueno Keiji , Watanabe Takahito , Ogino Hiroshi
Published: May 2003

Addition of 2,2′‐bipyridine (bpy) to an acetonitrile solution of dichlorogallyliron complex FpGaCl2 (1: Fp = (η‐C5H5)Fe(CO)2) afforded almost quantitatively a salt consisting of a cationic base‐stabilized gallylene complex [FpGaCl·bpy]+ ([3a]+) and an anionic complex [FpGaCl3]− ([4]−). Reaction of Fp′GaCl2 (Fp′ = Fp (1), Fp* (2); Fp* = (η‐C5Me5)Fe(CO)2) with NaBPh4 in the presence of a bidentate donor (Do2) gave [Fp′GaCl·Do2]BPh4 where Do2 was bpy or 1,10‐phenanthroline (phen). These cationic complexes may be useful precursors for the synthesis of gallyleneiron complexes with various substituents on the gallium atom. Indeed, reaction of [Fp*GaCl·phen]BPh4 ([5b]BPh4) with NaSpTol or Me3SiSpTol afforded the gallyleneiron complex [Fp*GaSpTol·phen]BPh4 ([6]BPh4), the first example of a gallium–transition metal complex having a thiolate group on the gallium atom. The molecular structures of [5b]BPh4 and [6]BPh4 were determined by single crystal X‐ray diffraction. Copyright © 2003 John Wiley & Sons, Ltd.
2‐Triorgano‐silyl, ‐germyl, ‐stannyl and ‐plumbyl derivatives of 1,3‐diisopropyl‐benzo‐1,3,2‐diazaborolidine and related compounds and their reactions with (η2‐C2H4)Pt(PPh3)2
Authors: Habereder Tassilo , Nöth Heinrich
Published: May 2003

A series of 1,3‐diisopropyl‐benzo‐1,3,2‐diazaborolidines 1–6 carrying ER3 substituents of Group 14 at the boron atom (E = C, Si, Ge, Sn, Pb; R = Me, Ph) have been prepared. Their molecular structures have been determined. As expected, the BE bond length increases along this series. Moreover, the orientation of the isopropyl groups relative to the ER3 substituent is influenced by the steric demand of these substituents. The 11B NMR data show a deshielding of the boron nucleus as the atomic weight of E increases. Oxidative addition reactions with (η2‐C2H4)Pt(PPh3)2 were successful only for the bromo derivative 1 and the trimethylstannyl derivative 5a; they failed for the triphenylsilyl, triphenylgermyl and triphenylstannyl compounds, indicating that steric effects play an important role in the successful oxidative addition to boryl‐substituted bis(triphenylphosphane)platinum(II) complexes. The triphenylplumbyl derivative 6 reacted with (η2‐C2H4)Pt(PPh3)2 to give cis‐ and trans‐diphenyl‐bis(triphenylphosphane)platinum besides Ph(Ph3Pb)Pt(PPh3)2. Obviously, the PbC bond is more reactive than the PbB bond. Cis‐Platinum–boryl complexes were also obtained from (Me2N)2BSnMe3 and (Me2N)2BGeMe3 while the boranes tmpB(SnMe3)2 and iPr2NB(SnMe3)2 were unreactive. Copyright © 2003 John Wiley & Sons, Ltd.
Simulation technique for wave generation
Authors: Aliabadi S. , Abedi J. , Zellars B. , Bota K. , Johnson A.
Published: May 2003

In this paper, we present a new finite element technique for simulation of water waves impacting on floating structures. The emphasis will be on the numerical methods for water wave generation and propagation. In our approach, the governing equations are the Navier–Stokes equations written for two incompressible fluids. An interface function with two distinct values serves as a marker identifying the location of the free‐surface. This function is transported throughout the computational domain with a time‐dependent advection equation. The stabilized finite element formulations are written and integrated in an arbitrary Lagrangian–Eulerian domain. This allows us to handle the motion of the physical boundaries, such as the wave generator surface by moving the computational nodes. In the mesh‐moving scheme, we assume that the computational domain is made of elastic materials. The linear elasticity equations are solved to obtain the displacements for each computational node. The numerical examples include 3D wave generation and wave breaking as they approach the coast, and the waves impacting on near‐shore support columns. Copyright © 2003 John Wiley & Sons, Ltd.
Parameter optimization in the regularized Shannon's kernels of higher‐order discrete singular convolutions
Authors: Xiong Wei , Zhao Yibao , Gu Yun
Published: May 2003

The δ‐type discrete singular convolution (DSC) algorithm has recently been proposed and applied to solve kinds of partial differential equations (PDEs). With appropriate parameters, particularly the key parameter r in its regularized Shannon's kernel, the DSC algorithm can be more accurate than the pseudospectral method. However, it was previously selected empirically or under constrained inequalities without optimization. In this paper, we present a new energy‐minimization method to optimize r for higher‐order DSC algorithms. Objective functions are proposed for the DSC algorithm for numerical differentiators of any differential order with any discrete convolution width. Typical optimal parameters are also shown. The validity of the proposed method as well as the resulted optimal parameters have been verified by extensive examples. Copyright © 2003 John Wiley & Sons, Ltd.
Sonographic staging of the developmental status of mouse embryos in utero
Authors: Chang Ching‐Pin , Chen Lei , Crabtree Gerald R.
Published: May 2003

Summary: In mouse developmental studies it is frequently desirable to isolate embryos of a specific age. However, the traditional staging of embryonic development based on postcoital dates often erroneously predicts the embryonic age, resulting in unwarranted sacrifice of the pregnant mother. Here we report a noninvasive way of staging embryonic development in utero. A clinical 14 MHz ultrasound system was employed to assess the morphology and size of developing embryos from embryonic day 7.5 to 18.5. We demonstrate that the developmental age of the mouse embryos can be accurately determined based on the sonographic morphology and size of the embryos. This noninvasive ultrasound application requires no anesthesia of the mice and the entire process of staging can be completed within 5–10 min. Empirically, this approach is applicable to mice of various genetic backgrounds and significantly enhances the efficiency of studying murine embryogenesis. genesis 36:7–11, 2003. © 2003 Wiley‐Liss, Inc.
Paracrine action of FGF4 during periimplantation development maintains trophectoderm and primitive endoderm
Authors: Goldin Sarah N. , Papaioannou Virginia E.
Published: May 2003

Summary: FGF4, a member of the fibroblast growth factor (FGF) family, is absolutely required for periimplantation mouse development, although its precise role at this stage remains unknown. The nature of the defect leading to postimplantation lethality of embryos lacking zygotic FGF4 is unclear and little is known about downstream targets of FGF4‐initiated signaling within the various cellular compartments of the blastocyst. Here we report that postimplantation lethality of Fgf4−/− embryos is unlikely to reflect strictly mitogenic requirements for FGF4. Rather, our results suggest that FGF4 is required to maintain trophectoderm and primitive endoderm identity at embryonic day 4.5. This result is consistent with the reported in vitro activity of FGF4 in maintaining trophoblast stem cells and with the requirement for receptor tyrosine kinase signaling in primitive endoderm formation. Thus, postimplantation lethality of Fgf4−/− embryos likely results from the failure of proper differentiation and function of extraembryonic cell types. genesis 36:40–47, 2003. © 2003 Wiley‐Liss, Inc.
Tendon chitosan tubes covalently coupled with synthesized laminin peptides facilitate nerve regeneration in vivo
Authors: Suzuki Masumi , Itoh Soichiro , Yamaguchi Isamu , Takakuda Kazuo , Kobayashi Hisatoshi , Shinomiya Kenichi , Tanaka Junzo
Published: May 2003

We have developed tendon chitosan tubes having the ability to bind peptides covalently, and the effectiveness of laminin peptides coupled to these tubular wall on nerve regeneration was examined in vivo. Bridge graft implantation (15 mm) into the sciatic nerve of SD rats was carried out using chitosan tubes having a triangular cross section containing either covalently bound intact laminin or the laminin peptides CDPGYIGSR or CSRARKQAASIKVAVSAD or being nontreated (N = 20 in each group). As a control, isografting (N = 5) was carried out. Three rats in each experimental group were sacrificed for histology observations after 1, 2, 4, 6, and 8 weeks. The total area of regenerating tissue in the tube and the length of the area where regenerating tissue attached to the inner surface of the tube were measured. In five rats from each experimental and control group, the latency quotient between the implanted and the nontreated site was determined 12 weeks after implantation. Furthermore, the percentage of myelinated axon area was measured at a 10‐mm distance from the distal anastomosed site. Histological findings suggest that the immobilized laminin, confirmed by immunostaining as long as 12 weeks postoperatively, as well as laminin oligopeptides may effectively assist nerve tissue extension. According to statistical analysis of the percentage neural tissue found in relation to evoked action potentials, the sequential treatments with YIGSR first followed by IKVAV matched the effectiveness of intact laminin in enhancing nerve regeneration. However, when compared with that after isografting, the enhancement of regenerated axon growth was less sufficient. © 2003 Wiley‐Liss, Inc.
EGF and NGF injected into the brain of old mice enhance BDNF and ChAT in proliferating subventricular zone
Authors: Tirassa Paola , Triaca Viviana , Amendola Tiziana , Fiore Marco , Aloe Luigi
Published: May 2003

The response of cells localized in the brain subventricular zone (SVZ) to growth factor stimulation has been largely described for development and adult life, whereas no information on their behavior during aging is available. To address the question of whether the cells in the SVZ of old mice respond to the intracerebroventricular administration of epidermal growth factor (EGF) and nerve growth factor (NGF), we studied the distribution of proliferating cells and the effects on ChAT and brain‐derived neurotrophic factor (BDNF) synthesis in forebrain and SVZ. It was found that the conjoint administration of EGF + NGF produced a major increase in ChAT expression in both forebrain and SVZ. The ChAT mRNA levels and the number of ChAT positive cells localized in the ventricular border and in the parenchyma of SVZ area were also increased significantly in the mice receiving EGF + NGF. Enhanced numbers of SVZ cells expressing proliferative markers were also discovered in EGF + NGF treated mice and some of these cells expressed cholinergic markers, as demonstrated by double immunostaining. In addition, EGF and NGF treatments significantly upregulate BDNF protein and mRNA levels in this brain region. The present study demonstrates that cells localized in SVZ of aged mouse brain retain the capacity to respond to EGF and NGF and that after stimulation with these two growth factors, the synthesis of ChAT and BDNF also increases. The implication that cells of the SVZ remain a reservoir of cholinergic and BDNF‐positive neurons in aged brain opens a new perspective for understanding the role of growth factors during neurodegenerative disorders associated with aging. © 2003 Wiley‐Liss, Inc.
Theory of magnetoelectric multiconductor transmission lines with application to chiral and gyrotropic lines
Authors: Marqués Ricardo , Mesa Francisco , Medina Francisco
Published: May 2003

This paper presents a theory of multiconductor transmission lines that allows for dealing with possible magnetoelectric couplings between the basic circuit quantities: voltage, current, and the per‐unit‐length charge and flux linkage. The magnetoelectric coupling is accounted for by the introduction of two new characteristic matrices of the line, the so‐called charge and current memductance matrices. The proposed theory is suitable for the description of lines loaded with gyrotropic, bi(iso/aniso)tropic chiral, pseudochiral, and Tellegen media. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 3–9, 2003
Triple‐band GPS trap‐loaded inverted L antenna array
Authors: Rama Rao B. , Smolinski M. A. , Quach Cuong C. , Rosario E. N.
Published: May 2003

Modernization of the GPS system that is currently underway will require future GPS antennas to operate at three separate frequency bands centered around 1176 MHz (L5 band), 1227 MHz (L2 band), and 1575 MHz (L1 band). A compact, low‐profile, right‐hand circularly polarized (RHCP), four‐element antenna array of trap‐loaded inverted L elements, capable of providing good gain coverage at all three frequency bands over the required bandwidth, is described in this paper. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 35–37, 2003
Novel polarization‐insensitive wavelength multiplexer/demultiplexer modules
Authors: Lu Ping , Ming‐Liu De , Chen Jun , Xiu‐Huang De , Xiang‐Wu Yue
Published: May 2003

We report here in detail a polarization‐insensitive arrayed‐waveguide grating (AWG) with an all‐optical polarization state controller (AOPSC). Only the TE0 mode can exist in this device; the TM0 mode will be cutoff. An eight‐channel AWG using 100‐GHz channel spacing is designed. Through simulation, we found that no polarization dependence was measured in the wavelength response. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 42–44, 2003
A general perturbational approach for synthesizing the Riccati‐type nonuniform transmission lines with arbitrarily specified reflection properties
Authors: Park Eui Joon
Published: May 2003

An adaptive nonlinear inversion method based on the Riccati equation in the dispersive inverse‐scattering problem is presented for synthesizing both single and coupled nonuniform transmission lines (NTLs) with arbitrary lobe‐like backward responses. In this method, the specified responses of those lines are first shaped by an optimum perturbation of inherent null points in the electrical‐length domain, and then sampled to straightforwardly determine the corresponding modal impedance profiles, hence avoiding the step‐by‐step segmentation process and overall optimization routines that plague most inversion schemes supporting non‐TEM modes. Some transformers and filters with controlled responses are illustrated for generality. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 52–56, 2003
A genetic algorithm approach to the design of ultra‐thin electromagnetic bandgap absorbers
Authors: Kern D. J. , Werner D. H.
Published: May 2003

A design methodology is presented for utilizing electromagnetic bandgap metamaterials, also known as artificial magnetic conductors, to realize ultra‐thin absorbers. One approach that has recently been proposed is to place a resistive sheet in close proximity to a frequency‐selective surface acting as an artificial magnetic conductor. However, we demonstrate in this paper that incorporating the loss directly into the frequency selective‐surface can eliminate the additional resistive sheet, thereby further reducing the overall thickness of the absorber. The geometrical structure and corresponding resistance of this lossy frequency‐selective surface is optimized by using a genetic algorithm to achieve the thinnest possible absorber. Two examples of genetically engineered electromagnetic bandgap metamaterial absorbers are presented and discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 61–64, 2003
A simple detection method of buried cylindrical targets applicable to landmines
Authors: Huynen I. , Steisel J. , Stockbroeckx B.
Published: May 2003

This paper presents a contribution to the problem of detecting cylindrical targets. We first show that cylindrical targets embedded into lossy dielectric media, such as soil have natural resonant frequencies which can be calculated using simplified models. Next, we demonstrate that those resonant frequencies can be observed experimentally using an adequate field detector and could be used as the signature of the presence of landmines into lossy soils. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 80–83, 2003
A new report of mesomelic camptomelia, polydactyly and Dandy–Walker complex in siblings
Authors: Planas S. , Peiró R. , Rubio R. , Villanueva R. , Serés A. , Carreras R.
Published: May 2003

Two male siblings with several malformations are reported. The anomalies detected in both fetuses were mesomelic camptomelia, postaxial hexadactyly and Dandy–Walker complex. There was only one similar previous report in the literature. This combination could represent a specific pattern of malformation or a new syndrome, with different variants. The parents' consanguinity and the recurrence in a subsequent pregnancy suggest an autosomal recessive inheritance pattern. Copyright © 2003 John Wiley & Sons, Ltd.