bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphorylation of Transcription Factor Sp1 during Herpes Simplex Virus Type 1 Infection
Authors: Kim Dool-Bboon , DeLuca Neal A. 
Published: July 2002

ABSTRACT

The expression of most herpes simplex virus type 1 (HSV-1) immediate-early (IE) and early (E) genes decreases late in productive infection. IE and E promoters contain various binding sites for cellular activators, including sites for Sp1, upstream of the TATA box, while late gene promoters generally lack such sites. To address the possibility that Sp1 function may be altered during the course of infection, the modification state and activity of Sp1 were investigated as a function of infection. Sp1 was quantitatively phosphorylated in HSV-1-infected cells without a significant change in abundance. The kinetics of accumulation of phosphorylated Sp1 immediately preceded the decline in E gene (thymidine kinase gene [
tk
]) mRNA abundance. Phosphorylation of Sp1 required ICP4; however, the proportion of phosphorylated Sp1 was reduced during infection in the presence of phosphonoacetic acid or in the absence of ICP27. While the DNA binding activity of Sp1 was not greatly affected by phosphorylation, the ability of phosphorylated Sp1 isolated from HSV-infected cells to activate transcription in vitro was decreased. These studies suggest that modification of Sp1 may contribute to the decrease of IE and E gene expression late in infection.
Characterization of Producer Cell-Dependent Restriction of Murine Leukemia Virus Replication
Authors: Serhan Fatima , Jourdan Nathalie , Saleun Sylvie , Moullier Philippe , Duisit Ghislaine 
Published: July 2002

ABSTRACT
We previously reported that the human bronchocarcinoma cell line A549 produces poorly infectious gibbon ape leukemia virus-pseudotyped Moloney murine leukemia virus (MLV). In contrast, similar amounts of virions recovered from human fibrosarcoma HT1080 cells result in 10-fold-higher transduction rates (G. Duisit, A. Salvetti, P. Moullier, and F. Cosset, Hum. Gene Ther. 10:189-200, 1999). We have now extended this initial observation to other type-C envelope (Env) pseudotypes and analyzed the mechanism involved. Structural and morphological analysis showed that viral particles recovered from A549 (A549-MLV) and HT1080 (HT1080-MLV) cells were normal and indistinguishable from each other. They expressed equivalent levels of mature Env proteins and bound similarly to the target cells. Furthermore, incoming particles reached the cytosol and directed the synthesis of linear viral DNA equally efficiently. However, almost no detectable circular DNAs could be detected in A549-MLV-infected cells, indicating that the block of infection resulted from defective nuclear translocation of the preintegration complex. Interestingly, pseudotyping of A549-MLV with vesicular stomatitis virus glycoprotein G restored the amount of circular DNA forms as well as the transduction rates to HT1080-MLV levels, suggesting that the postentry blockage could be overcome by endocytic delivery of the core particles downstream of the restriction point. Thus, in contrast to the previously described target cell-dependent Fv-1 (or Fv1-like) restriction in mammalian cells (P. Pryciak and H. E. Varmus, J. Virol. 66:5959-5966, 1992; G. Towers, M. Bock, S. Martin, Y. Takeuchi, J. P. Stoye, and O. Danos, Proc. Natl. Acad. Sci. USA 97:12295-12299, 2000), we report here a new restriction of MLV replication that relies only on the producer cell type.
The Simian Immunodeficiency Virus ΔnefVaccine, after Application to the Tonsils of Rhesus Macaques, Replicates Primarily within CD4+T Cells and Elicits a Local Perforin-Positive CD8+T-Cell Response
Authors: Stahl-Hennig Christiane , Steinman Ralph M. , Ten Haaft Peter , Überla Klaus , Stolte Nicole , Saeland Sem , Tenner-Racz Klara , Racz Paul 
Published: July 2002

ABSTRACTDeletion of thenefgene from simian immunodeficiency virus (SIV) strain SIVmac239 yields a virus that undergoes attenuated growth in rhesus macaques and offers substantial protection against a subsequent challenge with some SIV wild-type viruses. We used a recently described model to identify sites in which the SIVΔnefvaccine strain replicates and elicits immunity in vivo. A high dose of SIVΔnefwas applied to the palatine and lingual tonsils, where it replicated vigorously in this portal of entry at 7 days. Within 2 weeks, the virus had spread and was replicating actively in axillary lymph nodes, primarily in extrafollicular T-cell-rich regions but also in germinal centers. At this time, large numbers of perforin-positive cells, both CD8+T cells and CD3-negative presumptive natural killer cells, were found in the tonsil and axillary lymph nodes. The number of infected cells and perforin-positive cells then fell. When autopsy studies were carried out at 26 weeks, only 1 to 3 cells hybridized for viral RNA per section of lymphoid tissue. Nevertheless, infected cells were detected chronically in most lymphoid organs, where the titers of infectious virus could exceed by a log or more the titers in blood. Immunocytochemical labeling at the early active stages of infection showed that cells expressing SIVΔnefRNA were CD4+T lymphocytes. A majority of infected cells were not in the active cell cycle, since 60 to 70% of the RNA-positive cells in tissue sections lacked the Ki-67 cell cycle antigen, and both Ki-67-positive and -negative cells had similar grain counts for viral RNA. Macrophages and dendritic cells, identified with a panel of monoclonal antibodies to these cells, were rarely infected. We conclude that the attenuated growth and protection observed with the SIVΔnefvaccine strain does not require that the virus shift its characteristic site of replication, the CD4+T lymphocyte. In fact, this immunodeficiency virus can replicate actively in CD4+T cells prior to being contained by the host, at least in part by a strong killer cell response that is generated acutely in the infected lymph nodes.
Differential Selection of Specific Human Immunodeficiency Virus Type 1/JC499 Variants after Mucosal and Parenteral Inoculation of Chimpanzees
Authors: Wei Qing , Fultz Patricia N. 
Published: July 2002

ABSTRACT

Regardless of the route of transmission, it is generally accepted that the human immunodeficiency virus type 1 (HIV-1) quasispecies transmitted from an infected individual to an uninfected individual is genetically homogeneous. This finding and the observation that HIV-1 genotypes in recipients are minor variants in the donors suggest strongly that selection for specific variants occurs. However, most analyses have been limited to the V3 region of
env
. In addition, the exact time at which most new infections occurred was not known, making it almost impossible to analyze virus populations present in donor-recipient pairs at the time of HIV-1 transmission. To circumvent this problem, three chimpanzees were inoculated with a genetically defined stock of cell-free HIV-1/JC499 by one of three routes: intravenously or via the cervical or penile mucosa. PCR products of the C2-to-V5 region of
env
were amplified from both proviral DNA and virion RNA in blood samples collected soon after infection and were screened by heteroduplex analysis (HDA). Those PCR products with distinct HDA banding patterns were cloned and sequenced. In all three animals, transmitted variants encoded one of two V3-loop populations identified in the inoculum, indicating relative homogeneity in this region. However, different virus populations, defined by combinations of specific V4 and V5 sequences, were found when variants in the animal inoculated intravenously (at least 13 V4-plus-V5 combinations) were compared with those in the two animals inoculated by the mucosal routes (limited to only four V4-plus-V5 combinations). The only V4-plus-V5 population in variants found in all three chimpanzees was the major population in the inoculum, which contained viruses with more than 30 different V4-plus-V5 combinations. That the majority of the V4-plus-V5 genotypes in variants transmitted to all three animals were minor populations in the inoculum indicated that selective transmission defined by the V4-plus-V5 regions had occurred but that distinct populations were transmitted by parenteral versus mucosal routes. These results indicate that the putative homogeneity of HIV-1 variants in a newly infected individual might be an artifact of the region of the
env
gene evaluated and that regions other than V3 might play a major role in selective transmission.
Analysis of Duck Hepatitis B Virus Reverse Transcription Indicates a Common Mechanism for the Two Template Switches during Plus-Strand DNA Synthesis
Authors: Havert Michael B. , Ji Lin , Loeb Daniel D. 
Published: July 2002

ABSTRACT

The synthesis of the hepadnavirus relaxed circular DNA genome requires two template switches, primer translocation and circularization, during plus-strand DNA synthesis. Repeated sequences serve as donor and acceptor templates for these template switches, with direct repeat 1 (DR1) and DR2 for primer translocation and 5′r and 3′r for circularization. These donor and acceptor sequences are at, or near, the ends of the minus-strand DNA. Analysis of plus-strand DNA synthesis of duck hepatitis B virus (DHBV) has indicated that there are at least three other
cis
-acting sequences that make contributions during the synthesis of relaxed circular DNA. These sequences, 5E, M, and 3E, are located near the 5′ end, the middle, and the 3′ end of minus-strand DNA, respectively. The mechanism by which these sequences contribute to the synthesis of plus-strand DNA was unclear. Our aim was to better understand the mechanism by which 5E and M act. We localized the DHBV 5E element to a short sequence of approximately 30 nucleotides that is 100 nucleotides 3′ of DR2 on minus-strand DNA. We found that the new 5E mutants were partially defective for primer translocation/utilization at DR2. They were also invariably defective for circularization. In addition, examination of several new DHBV M variants indicated that they too were defective for primer translocation/utilization and circularization. Thus, this analysis indicated that 5E and M play roles in both primer translocation/utilization and circularization. In conjunction with earlier findings that 3E functions in both template switches, our findings indicate that the processes of primer translocation and circularization share a common underlying mechanism.
Synthesis of Aromatic Triynes as Precursors to Helicene Derivatives
Authors: Stará Irena G. , Kollárovič Adrian , Teplý Filip , Starý Ivo , Šaman David , Fiedler Pavel 
Published: July 2002

A general and versatile synthetic approach to a broad series of aromatic triynes as precursors to helicene derivatives has been developed. Employing a set of simple tools, triynes comprising the (phenylethynyl)benzene, 1-(phenylethynyl)naphthalene, and 1-(1-naphthylethynyl)- naphthalene moiety have been prepared in good to excellent yields throughout the whole reaction sequence. The methodology allows constructing various types of a junction between the central diarylacetylene moiety and the attached acetylene units to get the target triynes of general formula R-C≡C-CH2-X-CH2-Ar-C≡C-Ar'-CH2-X-CH2-C≡C-R or R-C≡C-CH2CH2-Ar-C≡C-Ar'-CH2CH2-C≡C-R (R = H, CH3, TMS, or TIPS; X = O, NTs, or C(CO2CH3)2; Ar/Ar' = 2-phenylene or 2-naphthylene).
Determinants of bone and blood lead concentrations in the early postpartum period
Authors: Brown Mary Jean , Hu Howard , Gonzales-Cossio Teresa , Peterson Karen E , Sanin Luz-Helena , Kageyama Maria de Luz , Palazuelos Eduardo , Aro Antonio , Schnaas Lourdes , Hernandez-Avila Mauricio 
Published: July 2002

OBJECTIVEThis study investigated determinants of bone and blood lead concentrations in 430 lactating Mexican women during the early postpartum period and the contribution of bone lead to blood lead.METHODSMaternal venous lead was measured at delivery and postpartum, and bone lead concentrations, measured with in vivo K-xray fluorescence, were measured post partum. Data on environmental exposure, demographic characteristics, and maternal factors related to exposure to lead were collected by questionnaire. Linear regression was used to examine the relations between bone and blood lead, demographics, and environmental exposure variables.RESULTSMean (SD) blood, tibial, and patellar lead concentrations were 9.5 (4.5) μg/dl, 10.2 (10.1) μg Pb/g bone mineral, and 15.2 (15.1) μg Pb/g bone mineral respectively. These values are considerably higher than values for women in the United States. Older age, the cumulative use of lead glazed pottery, and higher proportion of life spent in Mexico City were powerful predictors of higher bone lead concentrations. Use of lead glazed ceramics to cook food in the past week and increased patellar lead concentrations were significant predictors of increased blood lead. Patellar lead concentrations explained one third of the variance accounted for by the final blood lead model. Women in the 90th percentile for patella lead had an untransformed predicted mean blood lead concentration 3.6 μg/dl higher than those in the 10th percentile.CONCLUSIONSThis study identified the use of lead glazed ceramics as a major source of cumulative exposure to lead, as reflected by bone lead concentrations, as well as current exposure, reflected by blood lead, in Mexico. A higher proportion of life spent in Mexico City, a proxy for exposure to leaded gasoline emissions, was identified as the other major source of cumulative lead exposure. The influence of bone lead on blood lead coupled with the long half life of lead in bone has implications for other populations and suggests that bone stores may pose a threat to women of reproductive age long after exposure has declined.
Estimation of cumulative exposure to organophosphate sheep dips in a study of chronic neurological health effects among United Kingdom sheep dippers
Authors: Buchanan D , Pilkington A , Sewell C , Tannahill S N , Kidd M W , Cherrie B , Hurley J F 
Published: July 2002

OBJECTIVESTo derive a method for retrospectively estimating cumulative exposure to organophosphate (OP) pesticides among a cross section of United Kingdom sheep dippers, as part of a wider epidemiological study of neurological abnormality within this group of workers.METHODSA hygiene study of dipping sessions at 20 farms using diazinon based dips was carried out by two experienced occupational hygienists. Observations on the exposure of people to concentrate and dilute dip were recorded throughout each dipping session, together with the other relevant factors including the use and condition of protective clothing. Concentrations of urinary metabolites of diazinon were used to measure actual exposure to OPs. To estimate exposure in the subsequent epidemiological study, an occupational exposure history questionnaire was developed using results from the hygiene study and an empirical exposure model.RESULTSIn the hygiene study, increased urinary metabolites were associated with the handling of concentrate dip and exposure to dilute dip wash through splashing. Very few dippers wore the recommended protective clothing. The handling of concentrate dip was the principal source of exposure to OPs. Dipping task was used as a surrogate for splashing of dilute dip in retrospective exposure estimation. In the epidemiological study, cumulative exposure to OP sheep dips was highly correlated with the total number of dipping days, but not with age.CONCLUSIONSSheep dip concentrate is the most important source of OP exposure among sheep dippers and estimates of exposure to OPs during routine dipping should take due account of exposure to concentrate dip as well as to the dilute dip wash. The observed use of recommended protective clothing by most subjects was insufficient to allow a proper empirical assessment of its effectiveness.
Evaluation of patients admitted with hypoglycaemia to a teaching hospital in Central Anatolia
Authors: Güven M , Bayram F , Güven K , Kelestimur F 
Published: July 2002

Summary
Hypoglycaemia is one of the most common endocrine emergencies in practice. We analysed retrospectively the incidence and causes of hypoglycaemia in patients admitted to Erciyes University Medical School in Turkey between January 1991 and June 1998 because of hypoglycaemia. Charts were reviewed according to multiple variables including age, sex, blood glucose levels, renal and liver functions, diagnoses, symptoms, drugs, complications, sequelae, and survival status. During this period, 13 500 patients were hospitalised and hypoglycaemia was reported in 126 (0.9%) patients. The most common causes were diabetic treatments in 54 cases (42%), endocrine deficiencies in 25 cases (20%), and malignancy in 15 cases (12%), respectively. The leading endocrine deficiency was panhypopituitarism. Sheehan's syndrome was the most common cause of panhypopituitarism (44%). No underlying cause was diagnosed in seven cases. Nine patients died (7%) and neurological sequelae were observed in one patient with diabetes mellitus. We conclude that hypoglycaemia accounts for about 1% of hospital admissions. Although the hypoglycaemia could be attributed to hypoglycaemic agents in the treatment of diabetes mellitus in the majority of cases, Sheehan's syndrome was also found to be an important cause of hypoglycaemia in our hospital.
Can myasthenia gravis be diagnosed with the ‘ice pack test’? A cautionary note
Authors: Larner Andrew J , Thomas Dafydd J 
Published: July 2002

Summary
The ice pack test may be helpful in establishing that ptosis is due to ocular myasthenia gravis, since cold improves neuromuscular transmission. However, the role of the test in determining whether diplopia is of myasthenic origin has yet to be established.
FIBRE BUNDLE FORMULATION OF NONRELATIVISTIC QUANTUM MECHANICS IV: MIXED STATES AND EVOLUTION TRANSPORT'S CURVATURE
Authors: ILIEV BOZHIDAR Z. 
Published: July 2002

We propose a new systematic fibre bundle formulation of nonrelativistic quantum mechanics. The new form of the theory is equivalent to the usual one and is in harmony with the modern trends in theoretical physics and potentially admits new generalizations in different directions. In it the Hilbert space of a quantum system (from conventional quantum mechanics) is replaced with an appropriate Hilbert bundle of states and a pure state of the system is described by a lifting of paths or section along paths in this bundle. The evolution of a pure state is determined through the bundle (analog of the) Schrödinger equation. Now the dynamical variables and density operators are described via liftings of paths or morphisms along paths in suitable bundles. The mentioned quantities are connected by a number of relations derived in this work. The present fourth part of this series is devoted mainly to the fibre bundle description of mixed quantum states. We show that to the conventional density operator there corresponds a unique density lifting of paths for which the corresponding equations of motion are derived. It is also investigated the bundle description of mixed quantum states in the different pictures of motion. We calculate the curvature of the evolution transport and prove that it is curvature free iff the values of the Hamiltonian operator at different moments commute.
THE EFFECTS OF CIGARETTE SMOKING ON RABBIT TIBIAL VASCULAR ENDOTHELIUM
Authors: TU YUAN-KUN , UENG STEVE WEN-NENG 
Published: July 2002

Cigarette smoking is hazardous for various tissues in human. The cigarette smoke inhalation has been proved to delay bone healing. However, no previous study demonstrates the smoking effect on bony microcirculation. In this study, we investigated the effect of cigarette smoking on tibial vascular endothelium and blood flow by using the bone chamber model. Eighteen adult New Zealand rabbits were divided into 3 groups. Group 1: Control, Group 2: 1 week smoking, and Group 3: 6 weeks smoking. All these rabbits were then anesthetized, and their nutrient arteries of tibia were identified and cannulated. We put the tibia into bone chamber after cannulation, perfused with Krebs-Ringer solution (phase 1), and then compared the effect of vasospasm by norepinephrine dose-response curve (NEDRC). Acetylcholine (phase 2) and L-NMMA (phase 3) were also perfused and the NEDRC recorded. Acetylcholine can stimulate the release of nitric oxide and lower the NEDRC. L-NMMA inhibits NO synthesis in vascular endothelium, and hence results in vasoconstriction under various stimuli. Data collection and statistic processing were performed by ANOVA analysis. The NEDRC data in Group 1 (control) was set to be 100%. In phase 1 study, our results showed that 1 week cigarette smoking significantly increased NEDRC in Group 2 (142.5%, p<0.01). However, 6 weeks smoking strikingly boosted the response of NEDRC in Group 3 (226.5%, p<0.01). In phase 2 study, Group 2 tibia showed the NEDRC under acetylcholine perfusion to be without any difference in comparison with Group 1 (p>0.05). Nevertheless, Group 3 tibia showed significant vasospasm even under acetylcholine perfusion. In phase 3 study, L-NMMA perfused data revealed that; Group 3 tibia had the highest NEDRC, i.e. the most severe vasospasm. Based on our study, both short-term and long-term cigarette smoking are hazardous to the bony vascular endothelium. The nitric oxide production significantly attenuated in Group 2 and 3 tibia. However, the adverse effect of smoking seems reversible in short-term (Group 2). Long-term smoking (Group 3) causes irreversible damage to vascular endothelium and muscarinic receptor.
Updating relational databases through weak instance interfaces
Authors: Atzeni Paola , Torlone Riccardo 
Published: July 2002

The problem of updating databases through interfaces based on the weak instance model is studied, thus extending previous proposals that considered them only from the query point of view. Insertions and deletions of tuples are considered.
As a preliminary tool, a lattice on states is defined, based on the information content of the various states.
Potential results of an insertion are states that contain at least the information in the original state and that in the new tuple. Sometimes there is no potential result, and in the other cases there may be many of them. We argue that the insertion is deterministic if the state that contains the information common to all the potential results (the greatest lower bound, in the lattice framework) is a potential result itself. Effective characterizations for the various cases exist.
A symmetric approach is followed for deletions, with fewer cases, since there are always potential results; determinism is characterized as a consequence.
Sampling procedural shaders using affine arithmetic
Authors: Heidrich Wolfgang , Slusallek Philipp , Seidel Hans-Peter 
Published: July 2002

Procedural shaders have become popular tools for describing surface reflectance functions and other material properties. In comparison to fixed resolution textures, they have the advantage of being resolution-independent and storage-efficient.
While procedural shaders provide an interface for evaluating the shader at a single point, it is not easily possible to obtain an average value of the shader together with accurate error bounds over a finite area. Yet the ability to compute such error bounds is crucial for several interesting applications, most notably heirarchical area sampling for global illumination, using the finite element approach, and for generation of textures used in interactive computer graphics.
Using affine arithmetic for evaluating the shader over a finite area yields a tight, conservative error interval for the shader function. Compilers can automatically generate code for utilizing affine arithmetic from within shaders implemented in a dedicated language such as the RenderMann shading language.