bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acrosome‐specific gene AEP1: Identification, characterization and roles in spermatogenesis
Authors: Luk John M. , Lee Nikki P.Y. , Shum Cathy K. , Lam Brian Y. , Siu Annie F.M. , Che Chi‐Ming , Tam Po‐Chor , Cheung Annie N.Y. , Yang Z.M. , Lin Yi‐Nan , Matzuk Martin M. , Lee Kai‐Fai , Yeung William S.B. 
Published: August 2006

AbstractSpermatogenesis is a tightly regulated process leading to the development of spermatozoa. To elucidate the molecular spermatogenic mechanisms, we identified an acrosome‐specific gene AEP1 in spermatids, which is located in rat chromosome 17p14 with a transcript size of 3,091 bp encoding a signal peptide, zinc finger‐like motif, coiled‐coil region, several predicted glycosylation and phosphorylation sites. Northern blot and RT‐PCR analyses revealed the restricted expression of AEP1 to the testis only. In postnatal rat testes, AEP1 mRNA became detectable from postnatal 25 dpp (round spermatids) and onwards. By using in situ hybridization (ISH) and flow cytometry‐fluorescent ISH, only the haploid spermatids yielded the positive AEP1 signal. Immunohistochemistry showed that AEP1 was expressed in the acrosomal cap of late‐staged germ cells in rat testis, and co‐localized with the acrosomal marker, peanut agglutinin. The spatial expression of AEP1 immunoreactivity in testis was conserved among diverse mammalian species (rat, pig, monkey, human). To further study its roles in spermatogenesis, we showed AEP1 and β‐actin was associated together in complex by co‐immunoprecipitation in adult germ cells and by immunofluorescence assay in isolated spermatozoon. In human testes diagnosed with hypospermatogenesis, lower expression of AEP1 was observed, whereas there was no detectable signal in undescended testes. In short, AEP1 is an evolutionary‐conserved acrosome‐specific gene and likely functions in acrosome‐cap formation. J. Cell. Physiol. 209: 755–766, 2006. © 2006 Wiley‐Liss, Inc.
Bridging behavior and physiology: Ion‐channel perspective on mushroom body‐dependent olfactory learning and memory in Drosophila
Authors: Gasque Gabriel , Labarca Pedro , Delgado Ricardo , Darszon Alberto 
Published: August 2006

AbstractAn important body of evidence documents the differential expression of ion channels in brains, suggesting they are essential to endow particular brain structures with specific physiological properties. Because of their role in correlating inputs and outputs in neurons, modulation of voltage‐dependent ion channels (VDICs) can profoundly change neuronal network dynamics and performance, and may represent a fundamental mechanism for behavioral plasticity, one that has received less attention in learning and memory studies. Revisiting three paradigmatic mutations altering olfactory learning and memory in Drosophila (dunce, leonardo, amnesiac) a link was established between each mutation and the operation of VDICs in Kenyon cells, the intrinsic neurons of the mushroom bodies (MBs). In Drosophila, MBs are essential to the emergence of olfactory associative learning and retention. Abnormal ion channel operation might underlie failures in neuronal physiology, and be crucial to understand the abnormal associative learning and retention phenotypes the mutants display. We also discuss the only case in which a mutation in an ion channel gene (shaker) has been directly linked to olfactory learning deficits. We analyze such evidence in light of recent discoveries indicating an unusual ion current profile in shaker mutant MB intrinsic neurons. We anticipate that further studies of acquisition and retention mutants will further confirm a link between such mutations and malfunction of specific ion channel mechanisms in brain structures implicated in learning and memory. J. Cell. Physiol. 209: 1046–1053, 2006. © 2006 Wiley‐Liss, Inc.
Purinergic pathway suppresses the release of .NO and stimulates proteoglycan synthesis in chondrocyte/agarose constructs subjected to dynamic compression
Authors: Chowdhury T.T. , Knight M.M. 
Published: August 2006

AbstractMechanical loading plays a fundamental role in the physiological and pathological processes of articular cartilage. The application of dynamic compression to chondrocytes cultured in agarose, downregulates the release of nitric oxide (NO) and enhances cell proliferation and proteoglycan synthesis. We hypothesize that the observed metabolic changes in response to dynamic compression involve a purinergic signaling pathway. Chondrocyte/agarose constructs were subjected to dynamic compression (15%, 1 Hz, 48 h) in the presence of antagonists for the purinergic pathway. Gadolinium was used as a putative inhibitor of stretch‐activated calcium ion channels including adenosine 5′‐triphophate (ATP) release channels; suramin was employed as a P2 receptor antagonist and apyrase was used to catalyze the hydrolysis of extracellular ATP. The data presented demonstrate that in the absence of the inhibitor, dynamic compression suppressed .NO release. Treatment with gadolinium and suramin caused a compression‐induced upregulation of .NO release, a response abolished with apyrase. Compression‐induced stimulation of cell proliferation was reversed with gadolinium, suramin, or apyrase. By contrast, compression‐induced stimulation of proteoglycan synthesis was abolished under all treatment conditions. Thus, the purinergic pathway is important in suppressing the release of .NO and stimulation of proteoglycan synthesis. Indeed, high levels of .NO could trigger a downstream catabolic response and mediate the compression‐induced inhibition of cell proliferation. The current study demonstrates for the first time the importance of a purinergic pathway in mediating the metabolic response to dynamic compression and suppressing an inflammatory effect. J. Cell. Physiol. 209: 845–853, 2006. © 2006 Wiley‐Liss, Inc.
Insulin restores glucose inhibition of adenosine transport by increasing the expression and activity of the equilibrative nucleoside transporter 2 in human umbilical vein endothelium
Authors: Muñoz Gonzalo , Martín Rody San , Farías Marcelo , Cea Luis , Vecchiola Andrea , Casanello Paola , Sobrevia Luis 
Published: August 2006

AbstractL‐Arginine transport and nitric oxide (NO) synthesis (L‐arginine/NO pathway) are stimulated by insulin, adenosine or elevated extracellular D‐glucose in human umbilical vein endothelial cells (HUVEC). Adenosine uptake via the human equilibrative nucleoside transporters 1 (hENT1) and 2 (hENT2) has been proposed as a mechanism regulating adenosine plasma concentration, and therefore its vascular effects in human umbilical veins. Thus, altered expression and/or activity of hENT1 or hENT2 could lead to abnormal physiological plasma adenosine level. We have characterized insulin effect on adenosine transport in HUVEC cultured in normal (5 mM) or high (25 mM) D‐glucose. Insulin (1 nM) increased overall adenosine transport associated with higher hENT2‐, but lower hENT1‐mediated transport in normal D‐glucose. Insulin increased hENT2 protein abundance in normal or high D‐glucose, but reduced hENT1 protein abundance in normal D‐glucose. Insulin did not alter the reduced hENT1 protein abundance, but blocked the reduced hENT1 and hENT2 mRNA expression induced by high D‐glucose. Insulin effect on hENT1 mRNA expression in normal D‐glucose was blocked by NG‐nitro‐L‐arginine methyl ester (L‐NAME, NO synthase inhibitor) and mimicked by S‐nitroso‐N‐acetyl‐L,D‐penicillamine (SNAP, NO donor). L‐NAME did not block insulin effect on hENT2 expression. In conclusion, insulin stimulation of overall adenosine transport results from increased hENT2 expression and activity via a NO‐independent mechanism. These findings could be important in hyperglycemia‐associated pathological pregnancies, such as gestational diabetes, where plasma adenosine removal by the endothelium is reduced, a condition that could alter the blood flow from the placenta to the fetus affecting fetus growth and development. J. Cell. Physiol. 209: 826–835, 2006. © 2006 Wiley‐Liss, Inc.
Diphosphorylation of the myosin regulatory light chain enhances the tension acting on stress fibers in fibroblasts
Authors: Mizutani Takeomi , Haga Hisashi , Koyama Yoshikazu , Takahashi Masayuki , Kawabata Kazushige 
Published: August 2006

AbstractRegulation of the contractile force is crucial for cell migration, cell proliferation, and maintenance of cell morphology. Phosphorylation of the myosin II regulatory light chain (MRLC) is involved in these processes. To show whether the diphosphorylation of MRLC increases the tension acting on stress fibers, changes in the stiffness of fibroblasts expressing wild‐type MRLC and a mutant type, which cannot be diphosphorylated, on treatment with lysophosphatidic acid (LPA) were examined by a mechanical‐scanning probe microscope (M‐SPM). The LPA treatment increased cellular stiffness in the wild‐type MRLC expressing cells, while it had no effect on the mutated cells. Immunostaining showed that LPA stimulation induced the diphosphorylation of MRLC. These results suggest that the diphosphorylation of MRLC enhances the tension acting on stress fibers. J. Cell. Physiol. 209: 726–731, 2006. © 2006 Wiley‐Liss, Inc.
Ultrastructure of cyst shell and underlying membranes of three strains of the brine shrimp Artemia (Branchiopoda: Anostraca) from South India
Authors: Sugumar V. , Munuswamy N. 
Published: August 2006

AbstractThe cyst of Artemia has shell and membranous coverings over the embryo. The membranous coverings have special adaptive features to allow the physical changes accompanying repeated hydration and dehydration cycles that might occur and adversely influence postembryonic development. Whole and slices of cryptobiotic cysts were processed for electron microscopy to study the internal details and to compare the morphological architecture of three Artemia strains of South India. Surface topography of scanning electron microscopic (SEM) studies revealed distinct button shaped structures on the cyst of Puthalam strain. Transmission electron microscopic (TEM) studies of the cysts displayed the conventional pattern of anostracan crustaceans with outer cortex and alveolar layer, cuticular membranes, and the cytoplasmic inclusions namely nucleus, yolk droplets, lipoid bodies, and mitochondria. The prominent wavy outer cortex layer of Puthalam cysts corroborates the results of SEM studies. Microsc. Res. Tech. © 2006 Wiley‐Liss, Inc.
Characterisation of a P140K mutant O6‐methylguanine‐DNA‐methyltransferase (MGMT)‐expressing transgenic mouse line with drug‐selectable bone marrow
Authors: Kramer Belinda A. , Lemckert Frances A. , Alexander Ian E. , Gunning Peter W. , McCowage Geoffrey B. 
Published: August 2006

AbstractBackgroundGene transfer of the P140K mutant of O6‐methylguanine‐DNA‐methyltransferase (MGMT(P140K)) into hematopoietic stem cells (HSC) provides a mechanism for drug resistance and the selective expansion of gene‐modified cells in vivo. Possible clinical applications for this strategy include chemoprotection to allow dose escalation of alkylating chemotherapy, or combining MGMT(P140K) expression with a therapeutic gene in the treatment of genetic diseases. Our aim is to use MGMT(P140K)‐driven in vivo selection to develop allogeneic micro‐transplantation protocols that rely on post‐engraftment selection to overcome the requirement for highly toxic pre‐transplant conditioning, and to establish and maintain predictable levels of donor/recipient chimerism.MethodsUsing stably transfected murine embryonic stem (ES) cells, we have generated a C57BL/6 transgenic mouse line with expression of MGMT(P140K) within the hematopoietic compartment for use as a standard source of donor HSC in such models. Functional characterisation of transgene expression was carried out in chemotherapy‐treated transgenic mice and in allogeneic recipients of transgenic HSC.ResultsExpression of the transgene provided chemoprotection and allowed in vivo selection of MGMT(P140K)‐expressing cells in transgenic mice after exposure to O6‐benzylguanine (BG) and N,N′‐bis(2‐chloroethyl)‐N‐nitrosourea (BCNU). In an allogeneic transplant experiment in which transgenic HSC were engrafted into 129 strain recipients following low intensity conditioning (Busulfan, anti‐CD8, anti‐CD40Ligand), MGMT(P140K)‐expressing cells could be selected using chemotherapy.ConclusionsThis MGMT(P140K) transgenic mouse line provides a useful source of drug‐selectable donor cells for the development of non‐myeloablative allogeneic transplant models in which variation in transplant conditioning elements can be investigated independently of gene transfer efficiency. Copyright © 2006 John Wiley & Sons, Ltd.
High specificity of V3 serotyping among human immunodeficiency virus type‐1 subtype C infected patients with varying disease status and viral phenotype
Authors: Walker Polly R. , Cilliers Tonie , Choge Isaac A. , Taylor Natasha , Cohen Sarah S. , Morris Lynn 
Published: August 2006

AbstractV3 serotyping is a technique for determining HIV‐1 genetic subtype based on the binding of antibodies from patient sera or plasma to synthetic V3 peptides derived from subtype consensus sequences. Variation in the performance of this assay has been attributed to V3 sequence heterogeneity, the degree of which varies with patient disease progression, virus co‐receptor usage, and genetic subtype. This study assessed the performance of a competitive peptide enzyme immunoassay (cPEIA) in samples from HIV‐1 subtype C infected patients with varying disease profiles, including those with syncytium (SI) and non‐syncytium‐inducing (NSI) viruses. Out of 90 sera tested, 94.4% reacted strongly against the subtype C peptide. There was no significant difference in assay sensitivity among samples from advanced AIDS patients in which humoral immune response may be lower, nor among SI viruses which carry changes in the V3 sequence. Four samples were found to be cross‐reactive with other subtypes and one acutely infected patient sample was non‐reactive due to low anti‐gp120 antibody titers. A significantly higher number of samples showed secondary reactivity to subtype A, compared to other subtypes (P < 0.005). In conclusion, the assay was able to identify HIV‐1 subtype C infection with a high level of sensitivity (94%) irrespective of the stage of disease and therefore provides a valuable resource for the large‐scale epidemiological monitoring of the spread of HIV‐1 subtypes in South Africa. J. Med. Virol. 78:1262–1268, 2006. © 2006 Wiley‐Liss, Inc.
Low HBV‐DNA levels in end‐stage renal disease patients with HBeAg‐negative chronic hepatitis B
Authors: Moutinho Renata S. , Perez Renata M. , Medina‐Pestana José O. , Figueiredo Mauro S. , Koide Sandra , Alberto Fernando Lopes , Silva Antonio Eduardo B. , Ferraz Maria Lucia G. 
Published: August 2006

AbstractIn end‐stage renal disease patients treated by hemodialysis with HBeAg‐negative chronic hepatitis B virus (HBV) infection, the evaluation of the presence of viral replication is essential in the assessment for renal transplantation. Data on HBV viral load, prevalence of precore mutations, as well as the influence of HCV coinfection on HBV‐DNA levels in this group of patients is scarce. The aim of this study was to determine the HBV viral load in HBsAg‐positive/HBeAg‐negative hemodialysis patients; to compare HBV‐DNA levels between isolated HBV infection carriers and HBV‐HCV coinfected patients, and to evaluate the prevalence of precore mutations in these patients. Fifty hemodialysis patients with chronic HBeAg‐negative HBV infection were studied. Viral load was determined by PCR (Amplicor HBV Monitor‐Roche). The detection of precore mutations was made by sequencing. Of a total of 50 patients, 76% were male, with a mean age of 44 ± 11 years. Anti‐HCV was positive in 56% of patients. HBV‐DNA was undetectable in 58% of patients; 24% had HBV‐DNA <10,000 copies/ml, 12% between 10,000–100,000 copies/ml, and only 6% had HBV‐DNA >100,000 copies/ml. There was no difference in the viral load of patients infected only by HBV and HBV‐HCV co‐infected patients (P = 0.96). Precore mutations were detected in only 8% of cases. In conclusion, hemodialysis patients with HBeAg‐negative HBV infection had a low viral load. Precore mutations were infrequent and the presence of anti‐HCV has not influenced the levels of HBV‐DNA. J. Med. Virol. 78:1284–1288, 2006. © 2006 Wiley‐Liss, Inc.
Microarray assay for detection and discrimination of Orthopoxvirus species
Authors: Ryabinin Vladimir A. , Shundrin Leonid A. , Kostina Elena B. , Laassri Majid , Chizhikov Vladimir , Shchelkunov Sergei N. , Chumakov Konstantin , Sinyakov Alexander N. 
Published: August 2006

AbstractA microarray method was developed for simultaneous detection and identification of six species of Orthopoxvirus (OPV) including Variola, Monkeypox, Cowpox, Camelpox, Vaccinia, and Ectromelia viruses. The method allowed us to discriminate OPV species from varicella‐zoster virus (VZV), Herpes Simplex 1 virus (HSV‐1), and Herpes Simplex 2 virus (HSV‐2) that cause infections with clinical manifestations similar to OPV infections. The nucleotide sequences of the C23L/B29R and the B19R genes identified for 86 and 72 different OPV strains, respectively, were used to design species‐specific microarray oligonucleotide probes (oligoprobes). The microarray also contained several oligoprobes selected from the ORF31, US4, and US5 genes of VZV, HSV‐1, and HSV‐2, respectively. The samples (from HSVs or OPVs) of ssDNAs for analyses were prepared by using asymmetric PCR followed by chemical labeling of ssDNA with Cy3 dye. DNA from 52 samples of various OPV species, two isolates of VZV, two of HSV‐1, and three of HSV‐2 were tested using the developed microarray assay; all tested viruses were accurately identified. To ensure the robustness of the microarray assay, three additional unrelated variola virus strains with unknown sequences of the C23L/B29R and the B19R genes were tested. In each instance the microarray unambiguously identified them as Variola virus species. The results obtained in this study demonstrated that this new microarray method is a valuable tool for the rapid and accurate detection and differentiation of these important viral pathogens. J. Med. Virol. 78:1325–1340, 2006. © 2006 Wiley‐Liss, Inc.
Response to long‐term lamivudine treatment in patients infected with hepatitis B virus genotypes A, B, and C
Authors: Kobayashi Mariko , Suzuki Fumitaka , Akuta Norio , Suzuki Yoshiyuki , Arase Yasuji , Ikeda Kenji , Hosaka Tetsuya , Sezaki Hitomi , Kobayashi Masahiro , Iwasaki Satomi , Sato Junko , Watahiki Sachiyo , Miyakawa Yuzo , Kumada Hiromitsu 
Published: August 2006

AbstractResponse to lamivudine treatment longer than 1 year was compared in 15 patients persistently infected with hepatitis B virus (HBV) genotype A, 38 with genotype B, and 449 with genotype C. Patients with genotype A were younger (median age 37 [range 24–49] vs. 47 [24–67] or 44 [18–73], P = 0.015), possessed hepatitis B e antigen (HBeAg) more frequently (73% vs. 21% or 56%, P < 0.001) and HBV DNA in higher levels (8.6 [6.1–8.7] vs. 6.5 [<3.7–8.7] or 6.5 [<3.7–8.7] log genome equivalents (LGE)/ml, P = 0.024) than those with genotype B or C. During lamivudine, YMDD mutants (89% vs. 53% or 42%, P = 0.0001) and breakthrough hepatitis developed more often (47% vs. 21% or 29%, P = 0.023) in patients with genotype A than B or C. YMDD mutants elicited more frequently in patients with genotype A than B or C who were positive (82% [9/11] vs. 25% [2/8] or 48% [117/245], P = 0.037) or negative for HBeAg (75% [3/4] vs. 30% [9/30] or 33% [68/204], P = 0.003). HBeAg (hazard ratio 2.1 [95% confidence interval 1.53–2.92], P < 0.001) and genotype A (2.78 [1.08–7.12], P = 0.034) enhanced the emergence of YMDD mutants by the Cox proportional hazard model. The risk for breakthrough hepatitis was increased by the baseline alanine aminotransferase level <500 IU/L (2.56 [1.82–5.50], P = 0.018), HBeAg (2.11 [1.40–3.16], P < 0.001), cirrhosis (1.92 [1.24–2.97], P = 0.004) and HBV DNA ≥8.0 LGE/ml (1.57 [1.04–2.36], P = 0.03); it was influenced by genotypes only in patients with HBeAg. In conclusion, HBV genotypes help in predicting response to long‐term lamivudine treatment and development of YMDD mutants in patients with chronic hepatitis B. J. Med. Virol. 78:1276–1283, 2006. © 2006 Wiley‐Liss, Inc.
Distinct patterns of evolution between respiratory syncytial virus subgroups A and B From New Zealand isolates collected over thirty‐seven years
Authors: Matheson James W. , Rich Fenella J. , Cohet Catherine , Grimwood Keith , Huang Q. Sue , Penny David , Hendy Michael D. , Kirman Joanna R. 
Published: August 2006

AbstractRespiratory syncytial virus (RSV) is the most important cause of viral lower respiratory tract infections in infants and children worldwide. In New Zealand, infants with RSV disease are hospitalized at a higher rate than other industrialized countries, without a proportionate increase in known risk factors. The molecular epidemiology of RSV in New Zealand has never been described. Therefore, we analyzed viral attachment glycoprotein (G) gene sequences from 106 RSV subgroup A isolates collected in New Zealand between 1967 and 2003, and 38 subgroup B viruses collected between 1984 and 2004. Subgroup A and B sequences were aligned separately, and compared to sequences of viruses isolated from other countries during a similar period. Genotyping and clustering analyses showed RSV in New Zealand is similar and temporally related to viruses found in other countries. By quantifying temporal clustering, we found subgroup B viruses clustered more strongly than subgroup A viruses. RSV B sequences displayed more variability in stop codon usage and predicted protein length, and had a higher degree of predicted O‐glycosylation site changes than RSV A. The mutation rate calculated for the RSV B G gene was significantly higher than for RSV A. Together, these data reveal that RSV subgroups exhibit different patterns of evolution, with subgroup B viruses evolving faster than A. J. Med. Virol. 78:1354–1364, 2006. © 2006 Wiley‐Liss, Inc.
Modulation of epitope‐specific anti‐hepatitis C virus E2 (anti‐HCV/E2) antibodies by anti‐viral treatment
Authors: Mancini Nicasio , Carletti Silvia , Perotti Mario , Romanò Luisa , Di Stefano Craxì Rosellina , Craxì Antonio , Zanetti Alessandro R. , Clementi Massimo , Burioni Roberto 
Published: August 2006

AbstractThe dynamic features of three specific anti‐hepatitis C virus (HCV) antibody subpopulations directed against different conformational epitopes of the viral E2 protein (HCV/E2) have been evaluated in patients with primary and persistent HCV infection; the three subpopulations are present in patients infected with different HCV genotypes and have shown a different activity using a pseudovirus neutralization assay (antibodies e301 and e137 exhibiting high neutralizing activity, while antibody e509 enhancement of HCV infectivity). In sequential samples from five patients with primary HCV infection and different virological outcome, all samples tested negative with the single exception of the e509 antibody in a patient not clearing the virus. In sequential samples from 28 patients with persistent infection under treatment with pegylated interferon‐α plus ribavirin (14 sustained virological responders and 14 non‐responders), the therapy did not selectively influence titers of the two neutralizing antibody subpopulations; otherwise, a net increase of the e509 antibody subpopulation related to enhancement of HCV infectivity was observed in non‐responders, but not in sustained virological responders (P = 0.0156). This increase was not related to the trend of total anti‐HCV/E2 response. The data indicate that a specific antibody response against these epitopes is elicited only late during the infection, thus not influencing virus clearance during primary infection, and that a selective increase of the antibody subpopulation enhancing virus infectivity is observed only in the cohort of patients not responding to antiviral therapy. J. Med. Virol. 78:1304–1311, 2006. © 2006 Wiley‐Liss, Inc.