bluuebunny/crossref_metadata_2025 huggingface dataset:
Age‐related differences in NMDA/metabotropic glutamate receptor binding in rat substantia nigra
Authors: Hedberg Thomas G. , Velı́šková Jana , Sperber Ellen F. , Nunes Magda L. , Moshé Solomon L.
Published: March 2003

Both N‐methyl‐d‐aspartate (NMDA) and quisqualate/AMPA‐insensitive metabotropic glutamate (mGlu) receptors mediate glutamate neurotransmission in substantia nigra (SN). In this work, NMDA and mGlu receptor sites in substantia nigra pars compacta (SNC) and pars reticulata were autoradiographically mapped in rat brains using specific binding of (+)3H‐MK801 or 3H‐glutamate, with saturating concentrations of NMDA, AMPA and quisqualate. In brains of both adult and postnatal day 15 (PN15) male rats, prepared at subjective mid‐day of a 12 h light/12 h dark (12 h L/12 h D) cycle, specific binding at NMDA and mGlu sites in substantia nigra was pronounced when compared with control binding. The (+)3H‐MK801 binding in adults was spatially heterogeneous. Overall binding density in pars compacta was higher relative to binding density in pars reticulata with a mean percent change () of 32%. Within the pars reticulata but not pars compacta, there were rostro‐caudal differences with considerably denser binding in the posterior compared with the anterior pars reticulata (). PN15 rats showed a less pronounced heterogeneity in pars compacta versus pars reticulata binding, (), and less rostro‐caudal differentiation in (+)3H‐MK801 binding density throughout pars reticulata (). 3H‐glutamate binding in both adult and PN15 rats was less dense overall than (+)3H‐MK801 binding. In adults, there was no difference in binding density between pars compacta and pars reticulata (), but there were marked heterogeneities when binding was compared between anterior versus posterior pars compacta (), and anterior versus posterior pars reticulata (). This rostro‐caudal heterogeneity in 3H‐glutamate binding density was also present in PN15 pars compacta () but not in pars reticulata. Our findings mirror similar anterior/posterior heterogeneities in the GABAergic system in adult and PN15 male rats and may reflect a developmental change in both the structure and anticonvulsant/proconvulsant properties of substantia nigra pars reticulata (SNR) with age.
Operational codes, institutional learning and the optimistic model of post-Communist social change: Conceptual criticism and empirical challenges from a Romanian case study
Authors: Aligica P.D.
Published: March 2003

This paper discusses the conceptual model behind the widespread belief that in post Communist societies, once the democratic and market institutions are introduced, the emerging values and beliefs engendered by those very institutions will create the conditions for the consolidation and reproduction of democracy and market economy. The model is subjected to a double assessment: a critical theoretical review followed by an empirical test conducted through a case study. Both raise questions regarding the realism of the model and show that the direct relationship between institutional structures, institutional learning and the emerging values and beliefs (defined in this study as ‘operational codes’), a key relationship on which the model is based, is difficult to establish and substantiate. The paper concludes by pointing out the necessity to further elaborate the initial model in order to accommodate problems such as the emergence of institutional rigidities and learning blockages, and the emergence of dysfunctional values (values and beliefs that do not support and reproduce but undermine the institutional structures that shaped them initially), and to incorporate a theory of institutional change in which the evolution and change of beliefs, ideas and values play a much more preeminent place.
Putin’s federal reforms and the consolidation of federalism in Russia: one step forward, two steps back!
Authors: Ross C.
Published: March 2003

This paper provides a detailed analysis of Putin’s radical overhaul of the Russian federal system and its impact on federalism and democratisation. Whilst not all of Putin’s reforms have been implemented fully, the reorganisation of the Federation Council, his usurpation of unilateral powers to dismiss regional assemblies and chief executives, combined with his creation of seven federal districts, make a mockery of federalism. There are real worries that Putin’s quest for a ‘dictatorship of law’ will be bought at the cost of civil liberties and the consolidation of democracy. At present it would appear that Putin is willing to sacrifice democracy in order to win unity. However, his attack on the sovereignty claims of the ethnic republics are surely just as likely to stir up nationist sentiments as to quell them.
Too sick to vote? Public health and voter turnout in Russia during the 1990s
Authors: Reitan Therese C.
Published: March 2003

Determinants of political participation and electoral turnout are still of great interest within political science and three broad types of factors have been found to influence turnout significantly; individual or area-specific traits, characteristics of the electoral systems, and features relating to the political climate in individual elections. Within the first group, socio-economic resources, typically education, income, and occupation, have been found to be particularly important. This article proposes that public health is also a relevant form of social and political resources at the aggregate level. Regional data on life expectancy and electoral turnout from Russia—a country with dramatically deteriorated public health during the 1990s—were therefore correlated with each other. Overall, correlations were positive and significant, and there is, then, reason to investigate further the possible relationship between public health and the propensity to turn out at elections.
l‐Arginine and mitomycin C‐induced nitric oxide release and apoptosis in human lymphocytes
Authors: Erden Ceyda Damla , Ekmekci Abdullah , Şahin Feride Iffet , Ergün Mehmet Ali , Öztürk Güler , Erbas Deniz
Published: March 2003

Nitric oxide (NO) is a free radical that is produced by a number of mammalian cell types from l‐arginine and a critical mediator that acts in many tissues to regulate a diverse range of physiological processes. The major metabolic end product for NO is nitrate (NO3) and nitrite (NO2), which are stable metabolites within tissue, plasma, and urine. Measurements of nitrate and nitrite values reveal alterations in NO production. Endogenously generated or exogenously applied NO causes DNA cleavage by endonuclease activation.

We investigated the effect of l‐arginine and mitomycin C (MMC) on cultured lymphocytes of healthy individuals. We observed chromosome breaks, apoptotic cells and increased NO levels after l‐arginine and MMC addition. In conclusion, our results confirmed that NO may be the cause of apoptotic cell death in l‐arginine added lymphocyte culture.
Pharmacotherapeutics for Osteoporosis Prevention and Treatment
Authors: Davidson Michele R.
Published: March 2003

Osteoporosis is a silent disease that affects 10 million Americans; 80% of those affected are women. Although the disease is more common in postmenopausal Caucasian women, all ages and races are at risk. Osteoporosis can be a debilitating disease that can cause pain, fractures, depression, and social withdrawal. Signs of osteoporosis include kyphosis, loss of height, and protrusion of the abdomen. Because symptoms generally do not occur until after the disease has progressed, clinicians should include osteoporosis screening and preventative education as part of the regular gynecologic care. Diagnosis is typically made by a dual energy x‐ray absorpitometry (DEXA) scan. Treatment consists of dietary and lifestyle changes, along with pharmacologic intervention. Although hormone therapy has been shown to be effective in preventing osteoporosis, the risks of long‐term treatment with HRT are discussed. The following effective treatment options for women who have been diagnosed with the disease are discussed: bisphosphonates, calcitonin, and selective estrogen receptor modulators (SERMs). Because midwives regularly care for women of all ages, they are ideal candidates to provide women with preventative education, screening, counseling, and treatment.
Early Diagnosis and Treatment of Genuine Stress Urinary Incontinence in Women After Pregnancy: Midwives as Detectives
Authors: Peeker Iréne , Peeker Ralph
Published: March 2003

Genuine stress incontinence is often a hidden problem in that many women suffering from genuine stress incontinence after delivery do not seek medical advice. This article reviews signs and symptoms of genuine stress incontinence that, when identified, may enable midwives to initiate or suggest treatment as needed. A comprehensive literature search was performed in relevant medical databases. The following adverse risk factors for the development of genuine stress incontinence are vaginal delivery, multiparity, and obesity, with an increased risk for women who did not actively exert pelvic floor training. Prolonged second stage of labor and heavier babies were two factors associated with an increase in the risk of damage to the pelvic floor innervation as well as genuine stress incontinence. Several conservative treatment options, such as special instructions for pelvic floor training, the use of weight cones, and electrical stimulation, are reported to alleviate genuine stress incontinence symptoms.
Where Is the “E” in MCH? The Need for an Evidence‐Based Approach in Safe Motherhood
Authors: Miller Suellen , Sloan Nancy L. , Winikoff Beverly , Langer Ana , Fikree Fariyal F.
Published: March 2003

Measuring the impact of obstetric interventions on maternal mortality and/or morbidity is especially difficult in developing countries, where most maternal deaths occur. Therefore, program planning has been based on theory rather than proved effectiveness. After reviewing both the strategies that have been promoted to reduce maternal mortality and the adequacy of existing evidence used to justify their selection, the investigators highlight reasons why rigorous criteria for the selection and evaluation of interventions should be adopted. Adequate evaluation of intervention effectiveness under real‐life conditions in developing countries is an efficient way to identify interventions for large‐scale program replication and could speed progress in reducing maternal deaths.
Transoral versus Extraoral Reduction of Mandible Fractures: A Comparison of Complication Rates and other Factors
Authors: Toma Vincent S. , Mathog Robert H. , Toma Roger S. , Meleca Robert J.
Published: March 2003

OBJECTIVE

This retrospective study evaluates results and complications of the transoral and extraoral approaches for open reduction and internal fixation of mandibular body, angle, and ramus fractures. Our aim was to describe advantages and disadvantages of the techniques and to develop criteria for choosing between surgical approaches.

STUDY DESIGN AND SETTING

A retrospective chart review was performed on patients with mandible fractures occurring between August 1999 and October 2001 at a level I trauma center. Only mandibular body, angle, and ramus fractures requiring open reduction were selected for this study. Cases were evaluated for cause, age, gender, dentition, site and extent of fractures, surgical approach, postoperative complications, operative time, and postoperative occlusion.

RESULTS

Of the 227 patients with mandibular fractures, 78 had body, angle, or ramus fractures requiring open reduction. Of these, 36 were treated extraorally, and 42 were treated transorally. Criteria for selecting one procedure over another often involved training and surgeon experience and those factors normally considered important in defining the difficulty of treatment and prognosis of the patient. Seven of the 42 patients were converted from a transoral to an extraoral approach because of inadequate exposure. Similar complication rates occurred for the transoral and extraoral approaches, but because of the time required for converting from the transoral to extraoral approach, the average operative time was found to be increased in patients undergoing the transoral approach.

CONCLUSION AND SIGNIFICANCE

Decisions regarding treatment approaches for open reduction of mandible fractures often relate to surgeon experience and training, modified by factors that can affect uncomplicated healing such as fracture locations and displacement, comminution of the fracture, infection, dentition, and atrophic changes of the mandible. In some cases, the choice is affected by availability of equipment and experience of operating room personnel. More difficult cases involving an edentulous, atrophic mandible or comminution should be considered for extraoral exposure.
“Balanced” Orbital Decompression for Severe Graves' Orbitopathy: Technique with Treatment Algorithm
Authors: Ashutosh Kacker , Michael Kazim , Mark Murphy , Stephen Trokel , Lanny G. Close
Published: March 2003

BACKGROUND

Graves' orbitopathy can produce proptosis, compressive optic neuropathy, and extraocular motility abnormalities; symptoms result from an increase in orbital volume due to expansion of intraorbital fat, with or without extraocular muscle involvement.

STUDY DESIGN

We conducted a chart review of patients who underwent orbital decompression to treat Graves' orbitopathy. Twenty‐two orbits (13 patients) underwent orbital bone decompression, of which 17 orbits (9 patients) underwent the combined medial and lateral “balanced” decompression.

RESULTS

All patients had significant improvement with an average decrease in proptosis of 5.9 mm in the balanced decompression group. Restoration of normal optic nerve function was achieved in all patients with compressive optic neuropathy. Diplopia was noted in 4 patients (30.7%) preoperatively. Two patients had new postoperative diplopia (15.35%).

CONCLUSION

In our experience, “balanced” decompression results in a reduction of proptosis and improved optic nerve function and has a low incidence of complications.
Partial Laryngectomy after Irradiation Failure
Authors: Yiotakis John , Stavroulaki Pelagia , Nikolopoulos Thomas , Manolopoulos Leonidas , Kandiloros Dimitrios , Ferekidis Eletherios , Adamopoulos George
Published: March 2003

INTRODUCTION

Radiation therapy is often the first method of treating patients with early cancer of the glottis. There is a substantial failure rate among these patients. Total laryngectomy has usually been the means of treating patients with failure after radiation. In recent decades, partial laryngectomy has been used for salvage in such patients. This article will discuss the use of partial laryngectomy for radiation failure both from the oncologic result as well as the morbidity.

PATIENTS AND METHODS

Between 1984 and 1995, 27 patients with early‐stage laryngeal carcinoma underwent salvage partial laryngectomy after irradiation failure. Vertical laryngectomy was performed in 18 patients (13 with T1 N0 and 5 with T2 N0) and horizontal‐supraglottic laryngectomy in 9 patients (3 with T1 N0, 1 with T2 N0, and 5 with T2 N1). The mean follow‐up was 4.1 years.

RESULTS

Local control was obtained in 77.7% of patients with glottic lesions (T1: 84.6%; T2: 60%,P= NS) and in 55.5% of patients with supraglottic lesions (T1: 66.6%; T2: 50%;P= NS). There was no regional recurrence in the vertical laryngectomy group, whereas the regional control rate in the horizontal‐supraglottic laryngectomy group was 77.7%. Distant control was achieved in 94.4% of patients with glottic disease and in 77.7% of patients with supraglottic disease. The overall survival rate for glottic lesions was 88.8% (T1: 92.3%; T2:80%;P= NS) versus 66.6% for supraglottic lesions (T1: 100%; T2: 50%;P= NS).

CONCLUSION AND SIGNIFICANCE

Vertical laryngectomy was not associated with an increased complication rate. Morbidity in the horizontal‐supraglottic laryngectomy group was higher, but a satisfactory functional outcome was obtained in all cases. Therefore, in early laryngeal cancer (glottic T1‐T2, supraglottic T1) partial laryngectomy can be performed with good expectation of cure and satisfactory laryngeal function. In T2 supraglottic lesions, the oncologic results are less satisfactory; further research is required for developing more efficient complimentary or alternative treatments modalities.
A Reliable Radiologic Landmark for the Facial Nerve in Axial Temporal Bone Computed Tomography Scans
Authors: Bance Manohar , Erb Jason
Published: March 2003

OBJECTIVE

We sought to test the reliability of a radiologic marker in identifying the vertical portion of the facial nerve in axial computed tomography (CT) temporal bone scans.

STUDY DESIGN AND SETTING

At a tertiary care academic center, we used, with a random sample of 25 CT scans, a marker (the “B‐line”) to identify the facial nerve. The variations in distance from this marker to the facial nerve were measured.

RESULTS

This marker, which consists of a tangent line extrapolated from the posterior border of the basal turn of the cochlea, fell within 1 mm of the facial nerve on average. The average distance from the midpoint of the posterior border of the basal turn of the cochlea to the facial nerve was 11 ± 1 mm.

CONCLUSION

This is a very reliable marker for the vertical portion of the facial nerve.

SIGNIFICANCE

This marker can be used to rapidly find the facial nerve, even in diseased or postsurgical temporal bones.
Comparison of DNA Content Parameters in Paired, Fresh Tissue Pretreatment Biopsies and Surgical Resections from Squamous Cell Carcinoma of the Head and Neck
Authors: Rayes B. F. EL , Maciorowski Z. , Pietraszkiewicz H. , Ensley J. F.
Published: March 2003

OBJECTIVE

Cellular DNA characteristics derived from pretreatment biopsy (PTB) may become important for predicting treatment outcomes in patients with head and neck squamous cell cancer (HNSCC). Whether the PTB adequately represents the whole specimen is of critical importance.

STUDY DESIGN

In a series of >700 HNSCCs, we identified 59 cases in which the PTB and the surgical resection (SR) met the following criteria: PTB and SR were from the same site, and SR was obtained within 5 weeks of PTB with no intervening treatments.

RESULTS

Twenty‐nine percent of the PTB specimens were DNA diploid. Only 1 of the 11 subsequent DNA diploid SR was associated with a DNA aneuploid PTB (91% concordance). Of the 48 DNA aneuploid tumors, 3 were associated with DNA diploid PTB (94% concordance). Three other DNA aneuploid SRs were associated with PTB of poor quality.

CONCLUSION

With respect to DNA ploidy, PTB are representative of SR specimens.
Pain Intensity after Laseruvulopalatoplasty and Tonsillectomy
Authors: Kokki Hannu , Nikanne Elina , Aho Mikko , Virtaniemi Jukka
Published: March 2003

OBJECTIVE

The first objective of this study was to evaluate pain intensity and opioid consumption during the first 24 hours after uvulopalatoplasty and tonsillectomy in the hospital, and the second was to evaluate pain intensity and its progression during the first 2 weeks after surgery at home.

STUDY DESIGN AND SETTINGS

In a prospective parallel group study, 51 patients with uvulopalatoplasty or tonsillectomy were studied. Ketoprofen, a nonsteroidal antiinflammatory drug, and fentanyl citrate, an opioid, were used as analgesics.

RESULTS

Despite ketoprofen infusion and free access to a patient‐controlled pump with fentanyl citrate for rescue analgesia, inadequate pain relief was common both after uvulopalatoplasty (35%) and after tonsillectomy (28%) during the first 24 hours after surgery. The consumption of fentanyl citrate was similar after both operations. At home, pain intensity was highest in the mornings during the first 5 days, and 10 patients had some pain still after 2 weeks. Also at home, high pain scores were reported commonly in both groups.

CONCLUSION

Sgnificant pain after uvulopalatoplasty and tonsillectomy lasted for several days. Ketoprofen in the commercial capsule form proved to be too short acting for overnight pain relief.

SIGNIFICANCE

Pain treatment in patients with uvulopalatoplasty and tonsillectomy should be improved to allow patients a peaceful recovery after surgery.
Anatomic Variations of the Arteries of the Nasal Fossa
Authors: Babin Emmanuel , Moreau Sylvain , de Rugy Marc Goullet , Delmas Pierre , Valdazo André , Bequignon Arnaud
Published: March 2003

OBJECTIVE

This study was performed for knowledge about the vascular supply of the nasal fossa and a description of the site of division and number of branches of the sphenopalatine artery.

STUDY DESIGN

This study was performed on 10 fresh nonembalmed cadavers. Anatomic variations of nasal fossa arteries were studied.

METHODS

First, 10 cephalic anatomic preparations were injected with red color latex into the right and left carotid arteries. Then, these specimens were sagittally cut to dissect the sphenopalatine artery. Twenty vascularization cases were studied for the external branch of the sphenopalatine artery, and 10 cases were studied for the internal branch.

RESULTS

The principal observations were: 1, the sphenopalatine artery division is 18 times in the infratemporal fossa and twice in the nasal fossa; 2, the nasopalatine artery supplies blood to the lower part of the septum and its anterosuperior area; and 3, the vascularization of the external wall is via the sphenopalatine artery through the arteries of the meatus and conchae.

CONCLUSION

This study defines the vascular territories of the nasal fossa arteries and includes photographs of dissections.
Composite Chondroperichondrial Clip Tympanoplasty: The Triple “C” Technique
Authors: Sylvester Valentine Fernandes
Published: March 2003

OBJECTIVES

The study goal was to assess the success rate and efficacy of a myringoplasty (tympanoplasty type I) technique using a composite chondroperichondrial graft in a combined overlayunderlay fashion.

STUDY DESIGN

A retrospective analysis of patients subjected to the technique was conducted.

METHODS

A sample of 15 patients who met the inclusion criteria were reviewed for surgical results. All patients were treated by a single surgeon.

RESULTS

This transcanal technique provides minimal morbidity and excellent results in selected patients.

CONCLUSIONS

The described technique provides an effective method of closing nonmarginal perforations of the tympanic membrane.
Neural deficits in children with dyslexia ameliorated by behavioral remediation: Evidence from functional MRI
Authors: Temple Elise , Deutsch Gayle K. , Poldrack Russell A. , Miller Steven L. , Tallal Paula , Merzenich Michael M. , Gabrieli John D. E.
Published: March 2003

Developmental dyslexia, characterized by unexplained difficulty in reading, is associated with behavioral deficits in phonological processing. Functional neuroimaging studies have shown a deficit in the neural mechanisms underlying phonological processing in children and adults with dyslexia. The present study examined whether behavioral remediation ameliorates these dysfunctional neural mechanisms in children with dyslexia. Functional MRI was performed on 20 children with dyslexia (8–12 years old) during phonological processing before and after a remediation program focused on auditory processing and oral language training. Behaviorally, training improved oral language and reading performance. Physiologically, children with dyslexia showed increased activity in multiple brain areas. Increases occurred in left temporo-parietal cortex and left inferior frontal gyrus, bringing brain activation in these regions closer to that seen in normal-reading children. Increased activity was observed also in right-hemisphere frontal and temporal regions and in the anterior cingulate gyrus. Children with dyslexia showed a correlation between the magnitude of increased activation in left temporo-parietal cortex and improvement in oral language ability. These results suggest that a partial remediation of language-processing deficits, resulting in improved reading, ameliorates disrupted function in brain regions associated with phonological processing and produces additional compensatory activation in other brain regions.
Dopamine controls the firing pattern of dopamine neurons via a network feedback mechanism
Authors: Paladini Carlos A. , Robinson Siobhan , Morikawa Hitoshi , Williams John T. , Palmiter Richard D.
Published: March 2003

Changes in the firing pattern of midbrain dopamine neurons are thought to encode information for certain types of reward-related learning. In particular, the burst pattern of firing is predicted to result in more efficient dopamine release at target loci, which could underlie changes in synaptic plasticity. In this study, the effects of dopamine on the firing patterns of dopaminergic neurons
in vivo
and their electrophysiological characteristics
in vitro
were examined by using a genetic dopamine-deficient (DD) mouse model. Extracellular recordings
in vivo
showed that, although the firing pattern of dopamine neurons in normal mice included bursting activity, DD mice recordings showed only a single-spike pattern of activity with no bursts. Bursting was restored in DD mice after systemic administration of the dopamine precursor,
l
-3,4-dihydroxyphenylalanine (
l
-dopa). Whole-cell recordings
in vitro
demonstrated that the basic electrophysiology and pharmacology of dopamine neurons were identical between DD and control mice, except that amphetamine did not elicit a hyperpolarizing current in slices from DD mice. These data suggest that endogenously released dopamine plays a critical role in the afferent control of dopamine neuron bursting activity and that this control is exerted via a network feedback mechanism.
Further genetic evidence for a panic disorder syndrome mapping to chromosome 13q
Authors: Hamilton Steven P. , Fyer Abby J. , Durner Martina , Heiman Gary A. , Baisre de Leon Ada , Hodge Susan E. , Knowles James A. , Weissman Myrna M.
Published: March 2003

Substantial evidence supports that there is a genetic component to panic disorder (PD). Until recently, attempts at localizing genes for PD by using standard phenotypic data have not proven successful. Previous work suggests that a potential subtype of PD called the panic syndrome exists, and it is characterized by a number of medical conditions, most notably bladder/renal disorders. In the current study, a genome scan with 384 microsatellite markers was performed on 587 individuals in 60 multiplex pedigrees segregating PD and bladder/kidney conditions. Using both single-locus and multipoint analytic methods, we found significant linkage on chromosome 22 (maximum heterogeneity logarithm of odds score = 4.11 at D22S445) and on chromosome 13q (heterogeneity logarithm of odds score = 3.57 at D13S793) under a dominant-genetic model and a broad phenotypic definition. Multipoint analyses did not support the observation on chromosome 22. The chromosome 13 findings were corroborated by multipoint findings, and extend our previous findings from 19 of the 60 families. Several other regions showed elevated scores by using when one analytic method was used, but not the other. These results suggest that there are genes on chromosome 13q, and possibly on chromosome 22 as well, that influence the susceptibility toward a pleiotropic syndrome that includes PD, bladder problems, severe headaches, mitral valve prolapse, and thyroid conditions.
Pathogen DNA as target for host-generated oxidative stress: Role for repair of bacterial DNA damage in
Helicobacter pylori
colonization
Authors: O'Rourke Eyleen J. , Chevalier Catherine , Pinto A. Viviana , Thiberge Jean Michel , Ielpi Luis , Labigne Agnès , Radicella J. Pablo
Published: March 2003

Helicobacter pylori
elicits an oxidative stress during host colonization. This oxidative stress is known to cause lesions in the host DNA. Here we addressed the question as to whether the pathogen DNA is subject to lethal or mutational damage by the host-generated oxidative response.
H. pylori
Hpnth
mutants unable to repair oxidized pyrimidines from the bacterial DNA were generated.
H. pylori
strains lacking a functional endonuclease III (HpNth) showed elevated spontaneous and induced mutation rates and were more sensitive than the parental strain to killing by exposure to oxidative agents or activated macrophages. Although under laboratory conditions the
Hpnth
mutant strain grows as well as the wild-type strain, in a mouse infection the stomach bacterial load gradually decreases while the population in the wild-type strain remains stable, showing that endonuclease III deficiency reduces the colonization capacity of the pathogen. In coinfection experiments with a wild-type strain,
Hpnth
cells are eradicated 15 days postinfection (p.i.) even when inoculated in a 1:9 wild-type:mutant strain ratio, revealing mutagenic lesions that are counterselected under competition conditions. These results show that the host effectively induces lethal and premutagenic oxidative DNA adducts on the
H. pylori
genome. The possible consequences of these DNA lesions on the adaptability of
H. pylori
strains to new hosts are discussed.
Interferon-inducible gene expression signature in peripheral blood cells of patients with severe lupus
Authors: Baechler Emily C. , Batliwalla Franak M. , Karypis George , Gaffney Patrick M. , Ortmann Ward A. , Espe Karl J. , Shark Katherine B. , Grande William J. , Hughes Karis M. , Kapur Vivek , Gregersen Peter K. , Behrens Timothy W.
Published: March 2003

Systemic lupus erythematosus (SLE) is a complex, inflammatory autoimmune disease that affects multiple organ systems. We used global gene expression profiling of peripheral blood mononuclear cells to identify distinct patterns of gene expression that distinguish most SLE patients from healthy controls. Strikingly, about half of the patients studied showed dysregulated expression of genes in the IFN pathway. Furthermore, this IFN gene expression “signature” served as a marker for more severe disease involving the kidneys, hematopoetic cells, and/or the central nervous system. These results provide insights into the genetic pathways underlying SLE, and identify a subgroup of patients who may benefit from therapies targeting the IFN pathway.
CloQ, a prenyltransferase involved in clorobiocin biosynthesis
Authors: Pojer Florence , Wemakor Emmanuel , Kammerer Bernd , Chen Huawei , Walsh Christopher T. , Li Shu-Ming , Heide Lutz
Published: March 2003

Ring A (3-dimethylallyl-4-hydroxybenzoic acid) is a structural moiety of the aminocoumarin antibiotics novobiocin and clorobiocin. In the present study, the prenyltransferase involved in the biosynthesis of this moiety was identified from the clorobiocin producer (Streptomyces roseochromogenes), overexpressed, and purified. It is a soluble, monomeric 35-kDa protein, encoded by the structural genecloQ. 4-Hydroxyphenylpyruvate and dimethylallyl diphosphate were identified as the substrates of this enzyme, withKmvalues determined as 25 and 35 μM, respectively. A gene inactivation experiment confirmed thatcloQis essential for ring A biosynthesis. Database searches did not reveal any similarity of CloQ to known prenyltransferases, and the enzyme did not contain the typical prenyl diphosphate binding site (N/D)DXXD. In contrast to most of the known prenyltransferases, the enzymatic activity was not dependent on the presence of magnesium, and in contrast to the membrane-bound polyprenyltransferases involved in ubiquinone biosynthesis, CloQ did not accept 4-hydroxybenzoic acid as substrate. CloQ and the similar NovQ from the novobiocin producer seem to belong to a new class of prenyltransferases.
Bacterial enterotoxins are associated with resistance to colon cancer
Authors: Pitari G. M. , Zingman L. V. , Hodgson D. M. , Alekseev A. E. , Kazerounian S. , Bienengraeber M. , Hajnóczky G. , Terzic A. , Waldman S. A.
Published: March 2003

One half million patients suffer from colorectal cancer in industrialized nations, yet this disease exhibits a low incidence in under-developed countries. This geographic imbalance suggests an environmental contribution to the resistance of endemic populations to intestinal neoplasia. A common epidemiological characteristic of these colon cancer-spared regions is the prevalence of enterotoxigenic bacteria associated with diarrheal disease. Here, a bacterial heat-stable enterotoxin was demonstrated to suppress colon cancer cell proliferation by a guanylyl cyclase C-mediated signaling cascade. The heat-stable enterotoxin suppressed proliferation by increasing intracellular cGMP, an effect mimicked by the cell-permeant analog 8-br-cGMP. The antiproliferative effects of the enterotoxin and 8-br-cGMP were reversed by L-
cis
-diltiazem, a cyclic nucleotide-gated channel inhibitor, as well as by removal of extracellular Ca
2+
, or chelation of intracellular Ca
2+
. In fact, both the enterotoxin and 8-br-cGMP induced an L-
cis
-diltiazem-sensitive conductance, promoting Ca
2+
influx and inhibition of DNA synthesis in colon cancer cells. Induction of this previously unrecognized antiproliferative signaling pathway by bacterial enterotoxin could contribute to the resistance of endemic populations to intestinal neoplasia, and offers a paradigm for targeted prevention and therapy of primary and metastatic colorectal cancer.
Induction of cyclooxygenase-2 in monocyte/macrophage by mucins secreted from colon cancer cells
Authors: Inaba Takaaki , Sano Hajime , Kawahito Yutaka , Hla Timothy , Akita Kaoru , Toda Munetoyo , Yamashina Ikuo , Inoue Mizue , Nakada Hiroshi
Published: March 2003

Up-regulation of cyclooxygenase-2 (COX-2) and overproduction of prostaglandins have been implicated in the initiation and/or progression of colon cancer. However, it is uncertain in which cells and how COX-2 is induced initially in the tumor microenvironment. We found that a conditioned medium of the colon cancer cell line, LS 180, contained a factor to induce COX-2 in human peripheral blood mononuclear cells. This factor was purified biochemically and revealed to be mucins. A small amount of mucins (≈100 ng of protein per ml) could elevate prostaglandin E2 production by monocytes. The mucins induced COX-2 mRNA and protein levels of monocytes in a dose- and time-dependent manner, indicating a COX-2-mediated pathway. We also have examined immunohistochemically the localization of COX-2 protein and mucins in human colorectal cancer tissues. It is noteworthy that COX-2-expressing macrophages were located around the region in which mucins were detectable, suggesting that COX-2 also was induced by mucins
in vivo
. These results suggest that mucins produced by colon cancer cells play a critical role in the initial induction of COX-2 in the tumor microenvironment.
Role of the conserved NPxxY(x)
5,6
F motif in the rhodopsin ground state and during activation
Authors: Fritze Olaf , Filipek Sławomir , Kuksa Vladimir , Palczewski Krzysztof , Hofmann Klaus Peter , Ernst Oliver P.
Published: March 2003

In the G protein-coupled receptor rhodopsin, the conserved NPxxY(x)
5,6
F motif connects the transmembrane helix VII and the cytoplasmic helix 8. The less geometrically constrained retinal analogue 9-demethyl-retinal prevents efficient transformation of rhodopsin to signaling metarhodopsin (Meta) II after retinal photoisomerization. Here, we demonstrate that Ala replacement mutations within the NPxxY(x)
5,6
F domain, which eliminate an interaction between aromatic residues Y306 and F313, allow formation of Meta II despite the presence of 9-demethyl-retinal. Also a disulfide bond linking residues 306 and 313 in the 9-demethyl-retinal-reconstituted mutant Y306C/F313C/C316S prevented Meta II formation, whereas the reduced form of the mutant readily transformed to Meta II after illumination. These observations suggest that the interaction between residues 306 and 313 is disrupted during the Meta I/Meta II transition. However, this enhancement in Meta II formation is not reflected in the G protein activation, which is dramatically reduced for these mutants, suggesting that changes in the Y306–F313 interaction also lead to a proper realigning of helix 8 after photoisomerization. The E134Q mutation, located in the second conserved motif, D(E)RY, rescues activity in 9-demethyl-retinal-reconstituted mutants to different degrees, depending on the position of the Ala replacement in the NPxxY(x)
5,6
F motif, thus revealing distinct roles for the NP and Y(x)
5,6
F portions. Our studies underscore the importance of the NPxxY(x)
5,6
F and D(E)RY motifs in providing structural constraints in rhodopsin that rearrange in response to photoisomerization during formation of the G protein-activating Meta II. The dual control of the structural rearrangements secures reliable transformation of quiescent rhodopsin to activating Meta II.
von Hippel–Lindau protein binds hyperphosphorylated large subunit of RNA polymerase II through a proline hydroxylation motif and targets it for ubiquitination
Authors: Kuznetsova Anna V. , Meller Jaroslaw , Schnell Phillip O. , Nash James A. , Ignacak Monika L. , Sanchez Yolanda , Conaway Joan W. , Conaway Ronald C. , Czyzyk-Krzeska Maria F.
Published: March 2003

The transition from transcription initiation to elongation involves phosphorylation of the large subunit (Rpb1) of RNA polymerase II on the repetitive carboxyl-terminal domain. The elongating hyperphosphorylated Rpb1 is subject to ubiquitination, particularly in response to UV radiation and DNA-damaging agents. By using computer modeling, we identified regions of Rpb1 and the adjacent subunit 6 of RNA polymerase II (Rpb6) that share sequence and structural similarity with the domain of hypoxia-inducible transcription factor 1α (HIF-1α) that binds von Hippel–Lindau tumor suppressor protein (pVHL). pVHL confers substrate specificity to the E3 ligase complex, which ubiquitinates HIF-α and targets it for proteasomal degradation. In agreement with the computational model, we show biochemical evidence that pVHL specifically binds the hyperphosphorylated Rpb1 in a proline-hydroxylation-dependent manner, targeting it for ubiquitination. This interaction is regulated by UV radiation.
Evidence for rotation of V
1
-ATPase
Authors: Imamura Hiromi , Nakano Masahiro , Noji Hiroyuki , Muneyuki Eiro , Ohkuma Shoji , Yoshida Masasuke , Yokoyama Ken
Published: March 2003

V
o
V
1
-ATPase is responsible for acidification of eukaryotic intracellular compartments and ATP synthesis of Archaea and some eubacteria. From the similarity to F
o
F
1
-ATP synthase, V
o
V
1
-ATPase has been assumed to be a rotary motor, but to date there are no experimental data to support this. Here we visualized the rotation of single molecules of V
1
-ATPase, a catalytic subcomplex of V
o
V
1
-ATPase. V
1
-ATPase from
Thermus thermophilus
was immobilized onto a glass surface, and a bead was attached to the D or F subunit through the biotin-streptavidin linkage. In both cases we observed ATP-dependent rotations of beads, the direction of which was always counterclockwise viewed from the membrane side. Given that three ATP molecules are hydrolyzed per one revolution, rates of rotation agree consistently with rates of ATP hydrolysis at saturating ATP concentrations. This study provides experimental evidence that V
o
V
1
-ATPase is a rotary motor and that both D and F subunits constitute a rotor shaft.
Hemese, a hemocyte-specific transmembrane protein, affects the cellular immune response in
Drosophila
Authors: Kurucz Eva , Zettervall Carl-Johan , Sinka Rita , Vilmos Peter , Pivarcsi Andor , Ekengren Sophia , Hegedüs Zoltán , Ando Istvan , Hultmark Dan
Published: March 2003

We have identified a previously undescribed transmembrane protein, Hemese, from
Drosophila melanogaster
blood cells (hemocytes), by using a monoclonal pan-hemocyte antibody. Heavy glycosylation is suggested by the heterogeneous size distribution, ranging between 37 and 70 kDa. Hemese expression is restricted to the cell surfaces of hemocytes of all classes, and to the hematopoietic organs. The sequence of the corresponding gene,
Hemese
(
He
), predicts a glycophorin-like protein of 15 kDa, excluding an N-terminal signal peptide, with a single hydrophobic transmembrane region. The extracellular region consists mainly of Ser/Thr-rich sequence of low complexity, with several potential O-glycosylation sites. Hemese contains phosphotyrosine and the cytoplasmic region has potential phosphorylation sites, suggesting an involvement in signal transduction. Depletion of Hemese by RNA interference has no obvious effect under normal conditions, but the cellular response to parasitic wasps is much enhanced. This finding indicates that Hemese plays a modulatory role in the activation or recruitment of the hemocytes.
Assessment of genetic susceptibility to ethanol intoxication in mice
Authors: Rustay Nathan R. , Wahlsten Douglas , Crabbe John C.
Published: March 2003

Increased use of gene manipulation in mice (e.g., targeted or random mutagenesis) has been accompanied by increased reliance on a very few rapid and simple behavioral assays, each of which aspires to model a human behavioral domain. Yet, each assay comprises multiple traits, influenced by multiple genetic factors. Motor incoordination (ataxia), a common characteristic of many neurological disorders, may reflect disordered balance, muscle strength, proprioception, and/or patterned gait. Impaired motor performance can confound interpretation of behavioral assays of learning and memory, exploration, motivation, and sensory competence. The rotarod is one of the most commonly used tests to measure coordination in mice. We show here that exactly how the rotarod test is performed can markedly alter the apparent patterns of genetic influence both in undrugged performance and sensitivity to ethanol intoxication. However, when tested with well chosen parameters, the accelerating rotarod test showed very high inter- and intralaboratory reliability. Depending on test conditions, ethanol can either disrupt or enhance performance in some strains. Genetic contribution to performance on the accelerating versus the fixed-speed rotarod assay can be completely dissociated under some test conditions, and multiple test parameters are needed to assess the range of genetic influence adequately.
Oligomeric and polymeric aggregates formed by proteins containing expanded polyglutamine
Authors: Iuchi S. , Hoffner G. , Verbeke P. , Djian P. , Green H.
Published: March 2003

Neurological diseases resulting from proteins containing expanded polyglutamine (polyQ) are characteristically associated with insoluble neuronal inclusions, usually intranuclear, and neuronal death. We describe here oligomeric and polymeric aggregates formed in cells by expanded polyQ. These aggregates are not dissociated by concentrated formic acid, an extremely effective solvent for otherwise insoluble proteins. Perinuclear inclusions formed in cultured cells by expanded polyQ can be completely dissolved in concentrated formic acid, but a soluble protein oligomer containing the expanded polyQ and released by the formic acid is not dissociated to monomer. In Huntington's disease, a formic acid-resistant oligomer is present in cerebral cortex, but not in cerebellum. Cortical nuclei contain a polymeric aggregate of expanded polyQ that is insoluble in formic acid, does not enter polyacrylamide gels, but is retained on filters. This finding shows that the process of polymerization is more advanced in the cerebral cortex than in cultured cells. The resistance of oligomer and polymer to formic acid suggests the participation of covalent bonds in their stabilization.
RNA interference of influenza virus production by directly targeting mRNA for degradation and indirectly inhibiting all viral RNA transcription
Authors: Ge Qing , McManus Michael T. , Nguyen Tam , Shen Ching-Hung , Sharp Phillip A. , Eisen Herman N. , Chen Jianzhu
Published: March 2003

Influenza A virus causes widespread infection in the human respiratory tract, but existing vaccines and drug therapy are of limited value. Here we show that short interfering RNAs (siRNAs) specific for conserved regions of the viral genome can potently inhibit influenza virus production in both cell lines and embryonated chicken eggs. The inhibition depends on the presence of a functional antisense strand in the siRNA duplex, suggesting that viral mRNA is the target of RNA interference. However, siRNA specific for nucleocapsid (NP) or a component of the RNA transcriptase (PA) abolished the accumulation of not only the corresponding mRNA but also virion RNA and its complementary RNA. These siRNAs also broadly inhibited the accumulation of other viral, but not cellular, RNAs. The findings reveal that newly synthesized NP and PA proteins are required for influenza virus transcription and replication and provide a basis for the development of siRNAs as prophylaxis and therapy for influenza infection in humans.
Structural specificity of heparin binding in the fibroblast growth factor family of proteins
Authors: Raman Rahul , Venkataraman Ganesh , Ernst Steffen , Sasisekharan V. , Sasisekharan Ram
Published: March 2003

Heparin and heparan sulfate glycosaminoglycans (HSGAGs) mediate a wide variety of complex biological processes by specifically binding proteins and modulating their biological activity. One of the best studied model systems for protein–HSGAG interactions is the fibroblast growth factor (FGF) family of molecules, and recent observations have demonstrated that the specificity of a given FGF ligand binding to its cognate receptor (FGFR) is mediated by distinct tissue-specific HSGAG sequences. Although it has been known that sulfate and carboxylate groups in the HSGAG chain play a key role by interacting with basic residues on the proteins, there is little understanding of how these ionic interactions provide the necessary specificity for protein binding. In this study, using all of the available crystal structures of different FGFs and FGF–HSGAG complexes, we show that in addition to the ionic interactions, optimal van der Waals contact between the HSGAG oligosaccharide and the protein is also very important in influencing the specificity of FGF–HSGAG interactions. Although the overall helical structure is maintained in the FGF-bound HSGAG compared with unbound HSGAG, we observe distinct changes in the backbone torsion angles of the oligosaccharide chain induced upon protein binding. These changes result in local deviations in the helical axis that provide optimal ionic and van der Waals contact with the protein. A specific conformation and topological arrangement of the HSGAG-binding loops of FGF, on the other hand, impose structural constraints that induce the local deviations in the HSGAG structure, thereby enabling maximum contact between HSGAG and the protein.
Comparative analyses of genomic locations and race specificities of loci for quantitative resistance to
Pyricularia grisea
in rice and barley
Authors: Chen Huilan , Wang Shiping , Xing Yongzhong , Xu Caiguo , Hayes Patrick M. , Zhang Qifa
Published: March 2003

Comparative genomic analyses have revealed extensive colinearity in gene orders in distantly related taxa in mammals and grasses, which opened new horizons for evolutionary study. The objective of our study was to assess syntenic relationships of quantitative trait loci (QTL) for disease resistance in cereals by using a model system in which rice and barley were used as the hosts and the blast fungus
Pyricularia grisea
Sacc. as the pathogen. In total, 12 QTL against three isolates were identified in rice; two had effects on all three isolates, and the other 10 had effects on only one or two of the three isolates. Twelve QTL for blast resistance were identified in barley; one had effect on all three isolates, and the other 11 had effects on only one or two of the three isolates. The observed isolate specificity led to a hypothesis about the durability of quantitative resistance commonly observed in many plant host-pathogen systems. Four pairs of the QTL showed corresponding map positions between rice and barley, two of the four QTL pairs had complete conserved isolate specificity, and another two QTL pairs had partial conserved isolate specificity. Such corresponding locations and conserved specificity suggested a common origin and conserved functionality of the genes underlying the QTL for quantitative resistance and may have utility in gene discovery, understanding the function of the genomes, and identifying the evolutionary forces that structured the organization of the grass genomes.