bluuebunny/crossref_metadata_2025_split huggingface dataset:
Death of CD4+T-Cell Lines Caused by Human Immunodeficiency Virus Type 1 Does Not Depend on Caspases or Apoptosis
Authors: Bolton Diane L. , Hahn Beom-Ik , Park Eugenia A. , Lehnhoff Laura L. , Hornung Felicita , Lenardo Michael J. 
Published: July 2002

ABSTRACTA critical aspect of AIDS pathogenesis that remains unclear is the mechanism by which human immunodeficiency virus type 1 (HIV-1) induces death in CD4+T lymphocytes. A better understanding of the death process occurring in infected cells may provide valuable insight into the viral component responsible for cytopathicity. This would aid the design of preventive treatments against the rapid decline of CD4+T cells that results in AIDS. Previously, apoptotic cell death has been reported in HIV-1 infections in cultured T cells, and it has been suggested that this could affect both infected and uninfected cells. To evaluate the mechanism of this effect, we have studied HIV-1-induced cell death extensively by infecting several T-cell lines and assessing the level of apoptosis by using various biochemical and flow cytometric assays. Contrary to the prevailing view that apoptosis plays a prominent role in HIV-1-mediated T-cell death, we found that Jurkat and H9 cells dying from HIV-1 infection fail to exhibit the collective hallmarks of apoptosis. Among the parameters investigated, Annexin V display, caspase activity and cleavage of caspase substrates, TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) signal, and APO2.7 display were detected at low to negligible levels. Neither peptide caspase inhibitors nor the antiapoptotic proteins Bcl-xLor v-FLIP could prevent cell death in HIV-1-infected cultures. Furthermore, Jurkat cell lines deficient in RIP, caspase-8, or FADD were as susceptible as wild-type Jurkat cells to HIV-1 cytopathicity. These results suggest that the primary mode of cytopathicity by laboratory-adapted molecular clones of HIV-1 in cultured cell lines is not via apoptosis. Rather, cell death occurs most likely via a necrotic or lytic form of death independent of caspase activation in directly infected cells.
Three Regions of the pRB Pocket Domain Affect Its Inactivation by Human Papillomavirus E7 Proteins
Authors: Dick Frederick A. , Dyson Nicholas J. 
Published: July 2002

ABSTRACT

A critical event in papillomavirus transformation of human cells is the inactivation of pRB by the E7 protein. E7, like many other viral oncoproteins, possesses a well-characterized LXCXE peptide motif that interacts with the pocket domain of pRB. Disruption of the LXCXE-binding cleft on pRB renders it resistant to E7 binding and inactivation. Such binding cleft mutants of pRB are capable of inducing a G
1
arrest in the human papillomavirus 18-transformed HeLa cell line. We show here that the efficient inactivation of pRB in HeLa cells does not simply depend on the integrity of the LXCXE-binding cleft. Multiple site-directed mutants that alter conserved surfaces of the pRB pocket domain cause HeLa cells to accumulate in G
1
. We divide these mutants into two classes: those that can be bound by E7 and those that cannot. The E7 interacting mutants include changes in conserved residues that lie in a groove between the A and B halves of the pocket. Surprisingly, none of these mutants show a clear defect in any of the known mechanisms for pRB inactivation by E7. Analysis of mutants that are compromised for E7 binding reveals that this interaction depends on both the LXCXE-binding cleft and on a conserved group of lysines adjacent to the cleft. These basic amino acids on pRB define a discrete interaction point with E7. These residues most likely form ionic interactions with conserved acidic amino acids on E7 since a stable pRB/E7 interaction was restored when the lysine residues on pRB and the acidic residues on E7 were interchanged.
Characterization of a Human Cytomegalovirus with Phosphorylation Site Mutations in the Immediate-Early 2 Protein
Authors: Heider Julie A. , Yu Yongjun , Shenk Thomas , Alwine James C. 
Published: July 2002

ABSTRACT

A human cytomegalovirus mutant (TN
sub
IE2P) was constructed with alanine substitutions of four residues (T27, S144, T233, and S234) previously shown to be phosphorylated in the immediate-early 2 (IE2) protein. This mutant grew as well as the wild type at both low and high multiplicities of infection. The mutant activated the major immediate-early, UL4, and UL44 promoters to similar levels, and with similar kinetics, as wild-type virus. However, the TN
sub
IE2P mutant virus transactivated an endogenous simian virus 40 early promoter 4 h earlier and to higher levels than the wild-type virus in infected human fibroblasts. The modification of the IE2 protein by SUMO-1 (i.e., its sumoylated state) was also examined.
Regional Clustering of Shared Neutralization Determinants on Primary Isolates of Clade C Human Immunodeficiency Virus Type 1 from South Africa
Authors: Bures Renata , Morris Lynn , Williamson Carolyn , Ramjee Gita , Deers Mark , Fiscus Susan A. , Abdool-Karim Salim , Montefiori David C. 
Published: July 2002

ABSTRACTClade C is one of the most prevalent genetic subtypes of human immunodeficiency virus type 1 (HIV-1) in the world today and one of the least studied with respect to neutralizing antibodies. Most information on HIV-1 serology as it relates to neutralization is derived from clade B. Clade C primary isolates of HIV-1 from South Africa and Malawi were shown here to resemble clade B isolates in their resistance to inhibition by soluble CD4 and their sensitivity to neutralization by human monoclonal antibody immunoglobulin G1b12 and, to a lesser extent, 2F5. Unlike clade B isolates, however, all 16 clade C isolates examined resisted neutralization by 2G12. Infection with clade C HIV-1 in a cohort of female sex workers in South Africa generated antibodies that neutralized the autologous clade C isolate and T-cell-line-adapted (TCLA) strains of clade B. Neutralization of clade B TCLA strains was much more sensitive to the presence of autologous gp120 V3 loop peptides compared to the neutralization of clade C isolates in most cases. Thus, the native structure of gp120 on primary isolates of clade C will likely pose a challenge for neutralizing antibody induction by candidate HIV-1 vaccines much the same as it has for clade B. The autologous neutralizing antibody response following primary infection with clade C HIV-1 in South Africa matured slowly, requiring at least 4 to 5 months to become detectable. Once detectable, extensive cross-neutralization of heterologous clade C isolates from South Africa was observed, suggesting an unusual degree of shared neutralization determinants at a regional level. This high frequency of cross-neutralization differed significantly from the ability of South African clade C serum samples to neutralize clade B isolates but did not differ significantly from results of other combinations of clade B and C reagents tested in checkerboard assays. Notably, two clade C serum samples obtained after less than 2 years of infection neutralized a broad spectrum of clade B and C isolates. Other individual serum samples showed a significant clade preference in their neutralizing activity. Our results suggest that clades B and C are each comprised of multiple neutralization serotypes, some of which are more clade specific than others. The clustering of shared neutralization determinants on clade C primary HIV-1 isolates from South Africa suggests that neutralizing antibodies induced by vaccines will have less epitope diversity to overcome at a regional level.
Evolutionary History of
Cucumber Mosaic Virus
Deduced by Phylogenetic Analyses
Authors: Roossinck Marilyn J. 
Published: July 2002

ABSTRACT

Cucumber mosaic virus
(CMV) is an RNA plant virus with a tripartite genome and an extremely broad host range. Previous evolutionary analyses with the coat protein (CP) and 5′ nontranslated region (NTR) of RNA 3 suggested subdivision of the virus into three groups, subgroups IA, IB, and II. In this study 15 strains of CMV whose nucleotide sequences have been determined were used for a complete phylogenetic analysis of the virus. The trees estimated for open reading frames (ORFs) located on the different RNAs were not congruent and did not completely support the subgrouping indicated by the CP ORF, indicating that different RNAs had independent evolutionary histories. This is consistent with a reassortment mechanism playing an important role in the evolution of the virus. The evolutionary trees of the 1a and 3a ORFs were more compact and displayed more branching than did those of the 2a and CP ORFs. This may reflect more rigid host-interactive constraints exerted on the 1a and 3a ORFs. In addition, analysis of the 3′ NTR that is conserved among all RNAs indicated that evolutionary constraints on this region are specific to the RNA component rather than the virus isolate. This indicates that functions other than replication are encoded in the 3′ NTR. Reassortment may have led to the genetic diversity found among CMV strains and contributed to its enormous evolutionary success.
Varied Persistent Life Cycles of Borna Disease Virus in a Human Oligodendroglioma Cell Line
Authors: Ibrahim Madiha S. , Watanabe Makiko , Palacios J. Alejandro , Kamitani Wataru , Komoto Satoshi , Kobayashi Takeshi , Tomonaga Keizo , Ikuta Kazuyoshi 
Published: July 2002

ABSTRACTBorna disease virus (BDV) establishes a persistent infection in the central nervous system of vertebrate animal species as well as in tissue cultures. In an attempt to characterize the life cycle of BDV in persistently infected cultured cells, we developed 30 clones by single-cell cloning from a human oligodendroglioma (OL) cell line after infection with BDV. According to the percentage of cells expressing the BDV major proteins, p40 (nucleoprotein) and p24 (phosphoprotein), the clones were classified into two types: type I (>20%) and type II (<20%). mRNAs corresponding to both proteins were detected by in situ hybridization (ISH) in a percentage of cells consistent with that for the protein expression in the two types. Surprisingly, ISH for the detection of the genomic RNA, mainly in type II, revealed a significantly larger cell population harboring the genomic RNA than that with the protein as well as the mRNA expression. By recloning from type II primary cell clones, the same phenotype was confirmed in the secondary cell clones obtained: i.e., low percentage of protein-positive cells and higher percentage of cells harboring the genomic RNA. After nerve growth factor treatment, the two types of clones showed increases in the percentage of cells expressing BDV-specific proteins that reached 80% in type II clones, in addition to increased expression levels per cell. Such enhancement might have been mediated by the activation of the mitogen-activated protein kinase in the clones as revealed by the detection of activated ERK1/2. Thus, our findings show that BDV may have established a persistent infection at low levels of viral expression in OL cells with the possibility of a latent infection.
Requirements for Budding of Paramyxovirus Simian Virus 5 Virus-Like Particles
Authors: Schmitt Anthony P. , Leser George P. , Waning David L. , Lamb Robert A. 
Published: July 2002

ABSTRACT
Enveloped viruses are released from infected cells after coalescence of viral components at cellular membranes and budding of membranes to release particles. For some negative-strand RNA viruses (e.g., vesicular stomatitis virus and Ebola virus), the viral matrix (M) protein contains all of the information needed for budding, since virus-like particles (VLPs) are efficiently released from cells when the M protein is expressed from cDNA. To investigate the requirements for budding of the paramyxovirus simian virus 5 (SV5), its M protein was expressed in mammalian cells, and it was found that SV5 M protein alone could not induce vesicle budding and was not secreted from cells. Coexpression of M protein with the viral hemagglutinin-neuraminidase (HN) or fusion (F) glycoproteins also failed to result in significant VLP release. It was found that M protein in the form of VLPs was only secreted from cells, with an efficiency comparable to authentic virus budding, when M protein was coexpressed with one of the two glycoproteins, HN or F, together with the nucleocapsid (NP) protein. The VLPs appeared similar morphologically to authentic virions by electron microscopy. CsCl density gradient centrifugation indicated that almost all of the NP protein in the cells had assembled into nucleocapsid-like structures. Deletion of the F and HN cytoplasmic tails indicated an important role of these cytoplasmic tails in VLP budding. Furthermore, truncation of the HN cytoplasmic tail was found to be inhibitory toward budding, since it prevented coexpressed wild-type (wt) F protein from directing VLP budding. Conversely, truncation of the F protein cytoplasmic tail was not inhibitory and did not affect the ability of coexpressed wt HN protein to direct the budding of particles. Taken together, these data suggest that multiple viral components, including assembled nucleocapsids, have important roles in the paramyxovirus budding process.
Congenital adrenal hyperplasia: management during critical illness
Authors: Charmandari E , Lichtarowicz-Krynska E J , Hindmarsh P C , Johnston A , Aynsley-Green A , Brook C G D 
Published: July 2002

BACKGROUNDLittle is known of the optimal dose and administration schedule of hydrocortisone in critically ill patients with congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency.AIMTo determine plasma cortisol concentrations after intravenous administration of hydrocortisone in children with CAH and to relate these to plasma cortisol concentrations achieved by endogenous secretion in the stress of critical illness in previously healthy children.METHODSPlasma cortisol concentrations were measured in 20 patients with classical CAH (median age 11.2 years, range 6.1–16.4) following intravenous administration of hydrocortisone 15 mg/m2; and in 60 critically ill mechanically ventilated children (median age 2.5 years, range 0.25–16.3) on admission to the paediatric intensive care unit and for 24 hours thereafter.RESULTSIn the CAH patients, plasma cortisol reached a mean peak of 1648.3 nmol/l (SD 511.9) within 10 minutes of the intravenous bolus, and fell rapidly thereafter; levels remained greater than 450 nmol/l for 2.5 hours only. In critically ill children, mean plasma cortisol on admission to the intensive care unit was 727 nmol/l (SD 426.1). Cortisol concentrations remained raised during the first 24 hours.CONCLUSIONSCritically ill patients with classical CAH may be best managed with a single intravenous hydrocortisone bolus followed by a constant rate infusion of hydrocortisone.
State anxiety responses to 60 minutes of cross training: Figure 1
Authors: Hale B S , Koch K R , Raglin J S 
Published: July 2002

Objectives: Significant reductions in state anxiety following bouts of aerobic exercise have been consistently noted, whereas changes are generally absent after acute resistance training. However, the influence of a single exercise session involving both modes on state anxiety has not been examined.Methods: To address this, state anxiety responses to 60 minutes of cross training were examined in 16 collegiate athletes (12 women, four men). Each subject completed two cross training exercise sessions (30 minutes of resistance training, 30 minutes of bicycle ergometry) in which the order of the exercises was reversed, with a minimum of one week between sessions. Each exercise mode was completed at about 70% of maximum. State anxiety (SAI-Y1) was assessed five minutes before, and 0, 10, and 60 minutes after exercise.Results: Repeated measures analysis of variance showed a significant (p<0.05) main effect for time. However, the main effect for order and the order by time interaction were not significant. Post hoc analysis showed that state anxiety was reduced (p<0.05) from baseline (mean (SD) = 34.8 (7.9)) at 10 minutes (32.1 (7.5)) and 60 minutes (30.4 (5.9)) after exercise, but not at 0 minutes (33.8 (6.9)).Conclusions: The results indicate that combined sessions of aerobic and resistance exercise are associated with reductions in state anxiety, and that the order in which the exercise is completed does not influence this response.
Helicobacter pylori infection induces hyperammonaemia in Mongolian gerbils with liver cirrhosis
Authors: Suto H , Azuma T , Ito S , Ohtani M , Dojo M , Ito Y , Kohli Y , Kuriyama M 
Published: July 2002

BACKGROUND AND AIMSWe previously reported the effect of Helicobacter pylori eradication on hyperammonaemia in patients with liver cirrhosis. However, the role of H pylori as a cause of hyperammonaemia is controversial. We developed an animal model with liver cirrhosis and investigated the effect ofH pylori infection on hyperammonaemia.MATERIALS AND METHODSFive week old male Mongolian gerbils were inoculated orally with broth culture of H pylori. Forty eight gerbils were divided into four groups. Gerbils not inoculated with H pylori were fed a commercial rodent diet (group A) or a choline deficient diet (group C). Gerbils inoculated with H pyloriwere fed the commercial rodent diet (group B) or the choline deficient diet (group D). Blood ammonia levels of the femoral vein and portal vein were measured 30 weeks later.RESULTSAll gerbils fed the choline deficient diet developed liver cirrhosis with fatty metamorphosis. The survival rate of group D was significantly lower than that of the other groups. Systemic and portal blood ammonia levels in group D were significantly higher than those in the other groups.CONCLUSIONSH pylori infection induces hyperammonaemia in gerbils with liver cirrhosis.
Who is my brother's keeper?
Authors: Kottow M H 
Published: July 2002

Clinical and research practices designed by developed countries are often implemented in host nations of the Third World. In recent years, a number of papers have presented a diversity of arguments to justify these practices which include the defence of research with placebos even though best proven treatments exist; the distribution of drugs unapproved in their country of origin; withholding of existing therapy in order to observe the natural course of infection and disease; redefinition of equipoise to a more bland version, and denial of post-trial benefits to research subjects.These practices have all been prohibited in developed, sponsoring countries, even though they invariably have pockets of poverty where conditions comparable to the Third World prevail. Furthermore, the latest update of the Declaration of Helsinki clearly decries double ethical standards in research protocols. Under these circumstances, it does not seem appropriate that First World scholars should propose and defend research and clinical practices with less stringent ethical standards than those mandatory in their own countries.Recent years have witnessed frequent reports of less stringent ethical standards being applied to both clinical and research medical practices, for the most part in the field of drug trials and drug marketing, initiated by developed countries in poorer nations. Still more unsettling, a number of articles have endorsed the policy of employing ethical norms in these host countries, which would be unacceptable to both the legislations and the moral standards of the sponsor nations. Also, these reformulations often contravene the Declaration of Helsinki or one of its updates. This paper is not so much concerned with the actual practices, which have been subjected to frequent scrutiny and publicly decried when gross misconduct occurred. Rather, my concern relates to the approval and support such practices have found in the literature on bioethics from authors who might be expected to use their energy and scholarship to explore and endorse the universalisability of ethics rather than to develop ad hoc arguments that would allow exceptions and variations from accepted moral standards. To this purpose, issue will be taken with arguments in three fields: medical and pharmaceutical practices, research strategies, and local application of research results.
Occupational exposure to formaldehyde and wood dust and nasopharyngeal carcinoma
Authors: Vaughan Thomas L , Stewart Patricia A , Teschke Kay , Lynch Charles F , Swanson G Marie , Lyon Joseph L , Berwick Marianne 
Published: July 2002

OBJECTIVESTo investigate whether occupational exposures to formaldehyde and wood dust increase the risk of nasopharyngeal cancer (NPC).METHODSA multicentred, population based case-control study was carried out at five cancer registries in the United States participating in the National Cancer Institute's SEER program. Cases (n=196) with a newly diagnosed NPC between 1987 and 1993, and controls (n=244) selected over the same period from the general population through random digit dialing participated in structured telephone interviews which inquired about suspected risk factors for the disease, including a lifetime history of occupational and chemical exposure. Histological type of cancer was abstracted from clinical records of the registries. Potential exposure to formaldehyde and wood dust was assessed on a job by job basis by experienced industrial hygienists who were blinded as to case or control status.RESULTSFor formaldehyde, after adjusting for cigarette use, race, and other risk factors, a trend of increasing risk of squamous and unspecified epithelial carcinomas was found for increasing duration (p=0.014) and cumulative exposure (p=0.033) but not for maximum exposure concentration. The odds ratio (OR) for people cumulatively exposed to >1.10 ppm-years was 3.0 (95% confidence interval (95% CI) 1.3 to 6.6) compared with those considered unexposed. In analyses limited to jobs considered definitely exposed, these trends became stronger. The associations were most evident among cigarette smokers. By contrast, there was no association between potential exposure to formaldehyde and undifferentiated and non-keratinising carcinomas. There was little evidence that exposure to wood dust increased risk of NPC, as modest crude associations essentially disappeared after control for potential exposure to formaldehyde.CONCLUSIONSThese results support the hypothesis that occupational exposure to formaldehyde, but not wood dust, increases risk of NPC. This association seems to be specific to squamous cell carcinomas. Established cohorts of workers exposed to formaldehyde and wood dust should continue to be monitored for NPC and other respiratory cancers. Future studies of NPC should take into account histological type in assessing risk from environmental and host factors.