bluuebunny/crossref_metadata_2025_split huggingface dataset:
The E1^E4 Protein of Human Papillomavirus Interacts with the Serine-Arginine-Specific Protein Kinase SRPK1
Authors: Bell Ian , Martin Ashley , Roberts Sally 
Published: March 2007

ABSTRACT
Human papillomavirus (HPV) infections of the squamous epithelium are associated with high-level expression of the E1^E4 protein during the productive phase of infection. However, the precise mechanisms of how E1^E4 contributes to the replication cycle of the virus are poorly understood. Here, we show that the serine-arginine (SR)-specific protein kinase SRPK1 is a novel binding partner of HPV type 1 (HPV1) E1^E4. We map critical residues within an arginine-rich domain of HPV1 E1^E4, and in a region known to facilitate E1^E4 oligomerization, that are requisite for SRPK1 binding. In vitro kinase assays show that SRPK1 binding is associated with phosphorylation of an HPV1 E1^E4 polypeptide and modulates autophosphorylation of the kinase. We show that SRPK1 is sequestered into E4 inclusion bodies in terminally differentiated cells within HPV1 warts and that colocalization between E1^E4 and SRPK1 is not dependent on additional HPV1 factors. Moreover, we also identify SRPK1 binding of E1^E4 proteins of HPV16 and HPV18. Our findings indicate that SRPK1 binding is a conserved function of E1^E4 proteins of diverse virus types. SRPK1 influences important biochemical processes within the cell, including nuclear organization and RNA metabolism. While phosphorylation of HPV1 E4 by SRPK1 may directly influence HPV1 E4 function during the infectious cycle, the modulation and sequestration of SRPK1 by E1^E4 may affect the ability of SRPK1 to phosphorylate its cellular targets, thereby facilitating the productive phase of the HPV replication cycle.
New Adenovirus Species Found in a Patient Presenting with Gastroenteritis
Authors: Jones Morris Saffold , Harrach Balázs , Ganac Robert D. , Gozum Mary M. A. , dela Cruz Wilfred P. , Riedel Brian , Pan Chao , Delwart Eric L. , Schnurr David P. 
Published: March 2007

ABSTRACT
An unidentified agent was cultured in primary monkey cells at the Los Angeles County Public Health Department from each of five stool specimens submitted from an outbreak of gastroenteritis. Electron microscopy and an adenovirus-specific monoclonal antibody confirmed this agent to be an adenovirus. Since viral titers were too low, complete serotyping was not possible. Using the DNase-sequence-independent viral nucleic acid amplification method, we identified several nucleotide sequences with a high homology to human adenovirus 41 (HAdV-41) and simian adenovirus 1 (SAdV-1). However, using anti-SAdV-1 sera, it was determined that this virus was serologically different than SAdV-1. Genomic sequencing and phylogenetic analysis confirmed that this new adenovirus was so divergent from the known human adenoviruses that it was not only a new type but also represented a new species (human adenovirus G). In a retrospective clinical study, this new virus was detected by PCR in one additional patient from a separate gastroenteritis outbreak. This study suggests that HAdV-52 may be one of many agents causing gastroenteritis of unknown etiology.
Purification of Host Cell Enzymes Involved in Adeno-Associated Virus DNA Replication
Authors: Nash Kevin , Chen Weijun , McDonald William F. , Zhou Xiaohuai , Muzyczka Nicholas 
Published: March 2007

ABSTRACT
Adeno-associated virus (AAV) replicates its DNA by a modified rolling-circle mechanism that exclusively uses leading strand displacement synthesis. To identify the enzymes directly involved in AAV DNA replication, we fractionated adenovirus-infected crude extracts and tested them in an in vitro replication system that required the presence of the AAV-encoded Rep protein and the AAV origins of DNA replication, thus faithfully reproducing in vivo viral DNA replication. Fractions that contained replication factor C (RFC) and proliferating cell nuclear antigen (PCNA) were found to be essential for reconstituting AAV DNA replication. These could be replaced by purified PCNA and RFC to retain full activity. We also found that fractions containing polymerase δ, but not polymerase ε or α, were capable of replicating AAV DNA in vitro. This was confirmed when highly purified polymerase δ complex purified from baculovirus expression clones was used. Curiously, as the components of the DNA replication system were purified, neither the cellular single-stranded DNA binding protein (RPA) nor the adenovirus-encoded DNA binding protein was found to be essential for DNA replication; both only modestly stimulated DNA synthesis on an AAV template. Also, in addition to polymerase δ, RFC, and PCNA, an as yet unidentified factor(s) is required for AAV DNA replication, which appeared to be enriched in adenovirus-infected cells. Finally, the absence of any apparent cellular DNA helicase requirement led us to develop an artificial AAV replication system in which polymerase δ, RFC, and PCNA were replaced with T4 DNA polymerase and gp32 protein. This system was capable of supporting AAV DNA replication, demonstrating that under some conditions the Rep helicase activity can function to unwind duplex DNA during strand displacement synthesis.
Unique Thermodynamic Response of Tipranavir to Human Immunodeficiency Virus Type 1 Protease Drug Resistance Mutations
Authors: Muzammil S. , Armstrong A. A. , Kang L. W. , Jakalian A. , Bonneau P. R. , Schmelmer V. , Amzel L. M. , Freire E. 
Published: March 2007

ABSTRACT

Drug resistance is a major problem affecting the clinical efficacy of antiretroviral agents, including protease inhibitors, in the treatment of infection with human immunodeficiency virus type 1 (HIV-1)/AIDS. Consequently, the elucidation of the mechanisms by which HIV-1 protease inhibitors maintain antiviral activity in the presence of mutations is critical to the development of superior inhibitors. Tipranavir, a nonpeptidic HIV-1 protease inhibitor, has been recently approved for the treatment of HIV infection. Tipranavir inhibits wild-type protease with high potency (

K
i

= 19 pM) and demonstrates durable efficacy in the treatment of patients infected with HIV-1 strains containing multiple common mutations associated with resistance. The high potency of tipranavir results from a very large favorable entropy change (−
T
Δ
S
= −14.6 kcal/mol) combined with a favorable, albeit small, enthalpy change (Δ
H
= −0.7 kcal/mol, 25°C). Characterization of tipranavir binding to wild-type protease, active site mutants I50V and V82F/I84V, the multidrug-resistant mutant L10I/L33I/M46I/I54V/L63I/V82A/I84V/L90M, and the tipranavir in vitro-selected mutant I13V/V32L/L33F/K45I/V82L/I84V was performed by isothermal titration calorimetry and crystallography. Thermodynamically, the good response of tipranavir arises from a unique behavior: it compensates for entropic losses by actual enthalpic gains or by sustaining minimal enthalpic losses when facing the mutants. The net result is a small loss in binding affinity. Structurally, tipranavir establishes a very strong hydrogen bond network with invariant regions of the protease, which is maintained with the mutants, including catalytic Asp25 and the backbone of Asp29, Asp30, Gly48 and Ile50. Moreover, tipranavir forms hydrogen bonds directly to Ile50, while all other inhibitors do so by being mediated by a water molecule.
Enhanced Replication of Human T-Cell Leukemia Virus Type 1 in T Cells from Transgenic Rats Expressing Human CRM1 That Is Regulated in a Natural Manner
Authors: Takayanagi Ryo , Ohashi Takashi , Yamashita Eizaburo , Kurosaki Yohei , Tanaka Kumiko , Hakata Yoshiyuki , Komoda Yasumasa , Ikeda Satoru , Tsunetsugu-Yokota Yasuko , Tanaka Yuetsu , Shida Hisatoshi 
Published: March 2007

ABSTRACTHuman T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia (ATL). To develop a better animal model for the investigation of HTLV-1 infection, we established a transgenic (Tg) rat carrying the human CRM1 (hCRM1) gene, which encodes a viral RNA transporter that is a species-specific restriction factor. At first we found that CRM1 expression is elaborately regulated through a pathway involving protein kinase C during lymphocyte activation, initially by posttranscriptional and subsequently by transcriptional mechanisms. This fact led us to use an hCRM1-containing bacterial artificial chromosome clone, which would harbor the entire regulatory and coding regions of the CRM1 gene. The Tg rats expressed hCRM1 protein in a manner similar to expression of intrinsic rat CRM1 in various organs. HTLV-1-infected T-cell lines derived from these Tg rats produced 100- to 10,000-fold more HTLV-1 than did T cells from wild-type rats, and the absolute levels of HTLV-1 were similar to those produced by human T cells. We also observed enhancement of the dissemination of HTLV-1 to the thymus in the Tg rats after intraperitoneal inoculation, although the proviral loads were low in both wild-type and Tg rats. These results support the essential role of hCRM1 in proper HTLV-1 replication and suggest the importance of this Tg rat as an animal model for HTLV-1.
Autologous Adrenal Medullary, Fetal Mesencephalic, and Fetal Adrenal Brain Transplantation in Parkinson′s Disease: A Long‐Term Postoperative Follow‐Up
Authors: Madrazo Ignacio , Franco-Bourland Rebecca , Aguilera Maricarmen , Ostrosky-Solis Feggy , Madrazo Mario , Cuevas Carlos , Catrejon Hugo , Guizar-Zahagun Gabriel , Magallon Eduardo 
Published: March 2007

We report on the clinical status of 5 patients with Parkinson′s disease (PD) 3 years after autologous adrenal medullary (AM)‐to‐caudate nucleus (CN) implanfion, and of 2 PD patients, 2 years after fetal ventral mesencephalon (VM)‐ and fetal adrenal (A)‐to‐CN homotransplantation. Current clinical evaluation of 4 of the AM grafted patients revealed sustained bilateral amelioration of their PD signs, most notably of rgidity, postural imbalance and gait disturbances, resulting in a substantial improvement in their quality of life. the disease‐related dystonia of one of them disappeared only 2 years after surgery. The levodopa requirements of 2 of these patients and the anticholinergic therapy of another have been reduced. In agreement with the satisfactory clinical evaluation of these 4 patients, their neuropsychological and electrophysiological improvements, initially registered 3 months after surgery, have been maintained for 3 years. After 1 year of significant recovery, the 5th patient of this group has almost returned to her preoperative state.The 2 homotransplanted patients also showed sustained bilateral improvement of their PD signs. Two years after surgery, the most improved signs of the fetal VM case were rigidity, bradykinesia, postural imbalance, gait disturbances and facial expression. The fetal A case has only shown amelioration of rigidity and bradykinesia. Neither of them has shown significant neuropsychological changes. Their current levodopa requirements are less than before surgery.The improvements shown here by PD patients after brain tissue grafts go beyond those obtained using any other therapeutic approach, when levodopa fails. Although more studies and the development of these procedures are obviously required, these initial human trials appear to be resisting the test of time.
Intraocular Retinal Transplantation: A Review
Authors: Hammer R. M. , Yinon U. 
Published: March 2007

This review covers intraocular transplantation of
retinal tissue. This has importance both for
theoretical understanding of retinal and neural
development and for possible future clinical
application.
Transplantation sites have ranged from the
anterior chamber through the retina to the subretinal
space.Transplanted tissue has ranged from whole
retina to specific retinal layers or specific types of
retinal cells. Both within‐species and inter‐species
transplants have been performed, and donor age has
ranged from embryonic to adult. The ability of
transplanted tissue to be accepted and to differentiate
in host eyes has been studied. The conditions under
which successful transplants are obtained, host‐graft
interactions, and transplantation methodologies have
been explored. Morphological, and to a small extent,
also functional characteristics of the transplants have
been studied.
Cytological Differences in the Localization of Glucocorticoid Receptor‐Like Imnunoreactivity in the Normal and Transplanted Pituitary Pars Intermedia
Authors: Iturriza Fermlín C. , Dumm César L. A. Gómez 
Published: March 2007

Glucocorticoid receptor‐like immunoreactivity
(GCRI) was found in the normal pituitary
pars intermedia (PI) when immunohistochemistry
was used. Since in previous studies we described
two kinds of cells in the denervated
(grafted) PI, i.e., “light cells” (overactive cells
which do not contain detectable melanocyte
stimulating hormone) and “dark cells” (hypoactive
cells which contain the hormone), it was
decided to investigate whether different patterns
of distribution of the receptors could be detected
in the grafted gland when compared with the
intact PI. Intact glands showed the receptors
located in the nucleus. In transplanted glands, it
was observed that light cells showed receptors in
both the nuclei and the cytoplasm; on the other
hand, dark cells displayed them in the nuclei
only, as is the case in all cells of the normal PI.We had previously interpreted dark cells as
dopamine‐indifferent, whereas light cells were
considered dopamine‐sensitive. The changes in
the distribution of GCR after denervation by
grafting, which only affected the light cells,
support the view of other authors that GCR of.
the pars intermedia are under the influence of
dopamine and reinforce our opinion that dark
cells are dopamine‐indifferent
Peripheral Nerve Transplantation: The Effects of Predegenerated Grafts and Immunosuppression
Authors: Trumble Thomas E. 
Published: March 2007

Research involving nerve transplantation has
shown that tissue rejection limits the neurologic
recovery unless the host is immunosuppressed.
This study investigates an alternative to permanent
or temporary immunosuppression using a
rat model with nerve transplants from Brown‐
Norway rat donors to bridge defects in the sciatic
nerve of Lewis rat recipients as these two
inbred strains differ at both major and minor
histocompatibility loci.The specific aim of this
study was to evaluate if predegenerated nerve
grafts decreased the tissue rejection and improved
the neurologic recovery of animals with
allogenic nerve grafts to avoid the problems associated
with either short‐ or long‐term immunosuppression.
The animals in the experimental
groups received cyclosporin‐A, predegencrated
grafts, both, or neither. The predegenerated
grafts were produced by division of the
nerve three weeks prior to grafting to allow for
Wallerian degeneration to occur. The outcome
was assessed by measurements stressing functional
recovery (sensory testing, gait analysis,
joint flexion contracture), studies of muscle recovery
(muscle weight and hydroxyproline concentration),
and histologic studies (axonal
counts and inflammatory reaction). The animals
receiving the predegenerated grafts without cyclosporin
did have an improved recovery (joint
flexion contracture 35° ± 8 ° and hydroxyproline
ratio 1.52 ± 0.16) as compared to the joint flexion contractures and hydroxyproline ratios of
the allograft group of animals without either cyclosporin‐
A or pretreatment and the ungrafted
control group (47° ± 18°, 1.68 ± 0.34, and 53° ±15°
,4.50 ± 0.27, respectively, p < 0.01). However,
all the isograft groups and allograft groups
with cyclosporin‐A, regardless of whether the
graft had been predegenerated or not, had
greater neurologic recovery than the allograft
group with predegenerated grafts but without
cyclosporin‐A by the same parameters (p <
0.01). Allograft groups with short‐term immunosuppression
with cyclosporin‐A did as well
as isograft groups, and isograft groups with predegenerated
grafts did not do any better than
isografts without pretreatment (p <0.01).Clinical Relevance: Predegenerated nerve allografts
will allow for greater neurologic recovery
than standard nerve allografts avoiding the
complications of immunosuppression, but the
level of recovery is less than that of recipients of
nerve allografts with immunosuppression. Nerve
transplants would avoid the problems of neurologic
deficits at the donor site and allow multiple
large deficits to be treated easily.
Adrenal Medullary Grafts Restore Olfactory Deficits andCatecholamine Levels of 6‐OHDA Amygdala Lesioned Animals
Authors: Fernández-Ruiz Juan , Guzmán Rubén , Martínez María Dolores , Miranda María Isabel , Bermúdez-Rattoni Federico , Drucker-Colín René 
Published: March 2007

Aside from motor and cognitive deficits,
Parkinson patients also manifest a little‐studied
olfactory deficit. Since in Parkinson′s disease
there is a dopamine depletion of the amygdala
due to mesocorticolimbic system degeneration,
we decided to test olfactory and taste
performance of 6‐OHDA amygdala lesioned
rats, as well as the possible restoration of either
function with adrenal medullary transplants.Two 6‐OHDA lesioned groups and one
control group were tested in the potentiation of
odor by taste aversion paradigm. On taste
aversion none of the groups showed any
impairment. In contrast, the 6‐OHDA lesioned
rats showed a marked impairment in olfactory
aversion. At this point, one of the lesioned
groups received a bilateral adrenal medullary
graft within the lesioned area. After two months,
all groups were submitted again to the
behavioral paradigm. Taste remained
unaffected, but the lesioned only group did not
recover either olfactory aversion or normal
catecholamine levels. The grafted group, on the
other hand, restored olfactory aversion and
catecholamine levels. It can be concluded from
this study that catecholamine depletion of the
amygdala is sufficient to produce a selective
olfactory deficit, not accompanied by taste
impairments, and that such a deficit can be
reversed by adrenal medullary transplants,
which in turn restore catecholamine levels.
Ultrastructural Circuitry in Retinal Cell Transplants to Rat Retina
Authors: Zucker Charles L. , Ehinger Berndt , Seiler Magdalene , Aramant Robert B. , Adolph Alan R. 
Published: March 2007

The development of five transplants of fetal
retinal tissue to adult rat eyes was examined
with the electron microscope. The transplants
were of 9 to 10 weeks total age after conception
in four cases and 20 weeks in one case. They
were at stage E15 when transplanted.
Transplants developed in both the epiretinal and
subretinal spaces.
The transplants were heterogeneously
developed with some parts showing almost
normal differentiation and others little.
Subretinal transplants examined in this study
were more developed than epiretinal grafts.
Photoreceptor cells developed both inner and
outer segments. Their synaptic terminals
possessed output ribbon synapses with
postsynaptic processes similar to those seen in
normal retinas. In regions corresponding to the
inner plexiform layer, the adult complement of
synapses was seen, including advanced features
such as serial synapses as well as reciprocal
synapses at bipolar cell dyads. Incompletely
differentiated synapses of both the amacrine and
bipolar cell types were often observed, especially
in the rat epiretinal transplants. Ganglion cell
processes could not be identified with certainty.
Although transplant cells were adjacent to
host photoreceptor cells and pigment
epithelium, obvious specializations or
interactions were not observed. The experiments
suggest that embryonic rat retinal cell
transplants develop most or perhaps all of the
structural components and neuronal circuitry
necessary to transduce light and process some
visual information.
Origin of Afferent Projections into Bovine Chromaffin Cell Implants in the Rat Periaqueductal Gray Determined by Retrograde and Anterograde Tracing
Authors: Ortega John D. , Sagen Jacqueline , Pappas George D. 
Published: March 2007

We have previously described long‐term
survival of isolated bovine chromaffin cell
suspension grafts in the periaqueductal gray of
adult rats. Electron microscopic analysis of the
graft sites revealed synapses on the transplanted
chromaffin cells. The origin of these synapses is
not known, but they are probably derived from
the host since the initial grafts were suspensions
of chromaffin cells that were essentially free of
other cell types.In order to determine the origin of the
observed synapses, retrograde and anterograde
tracer analyses, were performed on grafted rats
at 4 and 8 weeks after transplantation.
Following injection of the retrograde tracer
(Fluoro‐Gold) into graft sites, four major host
sites were labeled: hindbrain reticular
formation, substantia nigra, lateral
hypothalamus, and cingulate cortex. Injection of
anterograde tracer (rhodamine‐conjugated
dextranamine) into the substantia nigra, lateral
hypothalamus, and cingulate cortex produced
labeled fibers and terminals in and around 4
and 8 week old chromaffin cell graft sites. An
increase in both the number of retrogradely
labeled cells, as well as in the density of
anterogradely labeled fibers and terminals within
the graft site, was observed from 4 to 8
weeks.This study shows that graft innervation from
the host is primarily from areas that normally
project afferent fibers to the periaqueductal
gray. The increase in labeled fibers, and
terminals over 8 weeks suggests that de novo
synapse formation on grafted bovine chromaffin
cells is a continuous process that is dependent on
the regenerative capacity and plasticity of the
host neuronal network and the grafted bovine
chromaffin cells.
Regional Differences of Serotonin‐Mediated Synaptic Plasticity in the Chicken Spinal Cord With Development and Aging
Authors: Chen Ling , Hamaguchi Kayoko , Hamada Shun , Okado Nobuo 
Published: March 2007

Previous studies in our laboratory /3,17/ have demonstrated that serotonin (5‐HT) appears to have a trophic‐like effect in enhancing synapse formation and maintenance in both the developing and the adult central nervous system. In the present study, we focused on age‐related changes in the density of the axosomatic and axodendritic synapses and the number of 5‐HT‐positive fibers in the chicken spinal cord, with special reference to differences between the ventral (laminae VII and IX) and the dorsal (lamina I) horn. At 1 week posthatching (PIW),
a transient overproduction of synapses and 5‐HT‐immunoreactive fibers occurred in lamina IX; all parameters had returned to their initial levels by 1 month post‐hatching (PIM). The density of synapses further decreased by about 40% between P6M and P2Y (2 years
posthatching). Although the magnitude of the transient increase in lamina VII was less than that in lamina IX, the changing pattern of the
synapses and the 5‐HT‐positive fibers was similar in both regions. In the ventral horn, thin 5‐HT‐positive fibers were most prominent at
P1W and then decreased with development; thin 5‐HT‐positive fibers were still found at P6M but had almost disappeared by P2Y. By contrast, at
P2Y the density of the synapses and the 5‐HT‐positive fibers in the dorsal horn was even higher than that of younger animals.Reduction of 5‐HT levels in P2Y‐old chickens by p‐chlorophenylalanine (pCPA) administration decreased the synaptic density in lamina I but not in lamina IX. The results of this study demonstrate that 5‐HT‐mediated synaptic plasticity is markedly different in the ventral and dorsal horns of the aged chicken. In the ventral horn, synaptic plasticity reached a maximum at about P1W, remained stable in the young‐adult period, and then finally disappeared in the aged chicken. Conversely, the results suggest that in the dorsal horn, 5‐HT fibers continue to mediate the trophic influence on synaptic plasticity even in the old chicken.