bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytomegalovirus infection of the liver transplant: virological, histological, immunological, and clinical observations
Authors: Lautenschlager I. , Halme L. , Höckerstedt K. , Krogerus L. , Taskinen E. 
Published: April 2006

Abstract: The most common organ‐specific manifestation of cytomegalovirus (CMV) infection after liver transplantation is hepatitis. Here we retrospectively describe the detailed virological, histological, immunological, and clinical findings associated with CMV infection in 229 consecutive adult liver transplantation patients. CMV infection was diagnosed by pp65 antigenemia. From 439 liver biopsies, CMV antigens were demonstrated by immunohistochemistry and CMV DNA by hybridization. The Banff criteria were used for histology. The expression of various adhesion molecules (intercellular adhesion molecule‐1 [ICAM‐1], vascular cell adhesion molecule‐1 [VCAM‐1], endothelial leukocyte adhesion molecule‐1 [ELAM‐1]), their ligands (leukocyte function antigen‐1 [LFA‐1], very late antigen‐4 [VLA‐4], Sialyl‐LewisX‐molecule [SLeX]), and lymphoid activation markers (major histocompatibility complex [MHC] Class II, interleukin‐2‐receptor [IL‐2R]) was demonstrated by immunohistochemistry.CMV infection of the transplant occurred in 26 patients (11% of all 229 patients and 17% of the 151 patients with liver biopsy). The incidence was higher among seronegative (26%) than in seropositive recipients (9%), but most cases 18/26 (70%) were reactivations. The CMV pp65 antigenemia levels were usually high in primary infections (893±1069, range 50–3000 pp65+cells), but varied widely in reactivations (388±740, range 3–3000). The histological Banff score was slightly increased (2.3±0.9). Microabscesses, lymphocytic infiltration, Kupffer cell reaction, and parenchymal alterations were common but viral inclusions rare. CMV significantly (P<0.05) increased ICAM‐1 and VCAM‐1 expression and the number of LFA‐1, VLA‐4, and Class II‐positive lymphocytes in the graft. All CMV infections were successfully treated with antivirals. Intragraft CMV infection had no influence on the long‐term outcome, but biliary complications were common.In conclusion, CMV infection of the liver transplant occurred both in primary infection and in reactivation, and also in the cases with low pp65 antigenemia levels. Microabscesses and other histological alterations were common but viral inclusions rare. Increased adhesion molecule expression was associated with lymphocyte infiltration. Successfully treated CMV hepatitis had no influence on the long‐term clinical outcome.
Rejection rates in a randomised trial of tacrolimus monotherapy versus triple therapy in liver transplant recipients with hepatitis C virus cirrhosis
Authors: Samonakis D.N. , Mela M. , Quaglia A. , Triantos C.K. , Thalheimer U. , Leandro G. , Pesci A. , Raimondo M.L. , Dhillon A.P. , Rolles K. , Davidson B.R. , Patch D.W. , Burroughs A.K. 
Published: April 2006

Abstract: Background. Reducing immunosuppression not only reduces complications but also may lessen recurrent hepatitis C virus (HCV) infection after liver transplantation.Patients/Methods. HCV‐infected cirrhotic patients randomised to tacrolimus monotherapy (MT) or triple therapy (TT) using tacrolimus 0.1 mg/kg/day, azathioprine 1 mg/kg/day, and prednisolone 20 mg/day, tapering over 3 months.Results. Twenty‐seven patients (MT) and 29 (TT) – median follow up 661 days (range, 1–1603). Rejection episodes (protocol/further biopsies) within first 3 months and use of empirical treatment were evaluated. New rejection was diagnosed if repeat biopsy (5‐day interval) did not show improvement. Treated rejection episodes: 20 MT (15 biopsy‐proven) vs. 24 TT (21 biopsy‐proven), with 19 (MT) vs. 24 (TT) methylprednisolone boluses. Overall: 35 episodes (MT) and 46 (TT). Fewer MT patients had histological rejection (70%) than TT patients (86%), with fewer episodes of rejection (18.5% vs. 10%), and more moderate rejection (22% vs. 41%). The MT group had higher early tacrolimus levels. Rates of renal dysfunction, retransplantation, and death were not significantly different.Conclusion. Tacrolimus monotherapy is a viable immunosuppressive strategy in HCV‐infected liver transplant recipients.
cGMP‐Producing, Atrial Natriuretic Factor‐Responding Cells in the Rat Brain
Authors: de Vente J. , Bol J. G. J. M. , Steinbusch H. W. M. 
Published: April 2006

AbstractUsing an in vitro incubation method, we stimulated cGMP production in rat brain slices by rat ANF‐(103–126). The localization of the cells responding to this ANF stimulation with an increase in cGMP production was studied by cGMP immunocytochemistry. ANF‐responding cells were found in specific loci throughout the central nervous system of the rat. Regions containing the highest number of these cells were: the olfactory bulb, the lateral septum, the bed nucleus of the accessory olfactory tract, the mediobasal amygdala, the central grey area, the medial vestibular nucleus, and the nucleus of the solitary tract. Scattered ANF‐responding, cGMP‐immunoreactive cells were found in the hippocampus, the cingulate cortex, the ventral pallidum, the medial preoptic area, and the endopeduncular nucleus. ANF‐responding cells in these areas had the same morphology, that is, multipolar with numerous processes. The nature of these ANF‐responding cells was studied by sequential staining with an antiserum against glial fibrillary acidic protein (GFAP). In the hippocampus it was demonstrated that all ANF‐responding cells are astroglial cells. However, not all astroglial cells in this area showed a cGMP response, demonstrating a regional heterogeneity. ANF‐responding cells, having the appearance of neuronal cell bodies, could be found in the subfornical organ, and the hypothalamic paraventricular nucleus. Fibres producing cGMP immunoreactivity in response to ANF were found in the median preoptic nucleus, the medial preoptic area, and the dorsal hypothalamus.
Performance of Decorticated Rats on Fixed Interval and Fixed Time Schedules
Authors: Jaldow Eli J. , Oakley David A. , Davey Graham C. L. 
Published: April 2006

AbstractRats with neocortex totally removed (decorticates), rats with hippocampal lesions (hippocampals), and their surgical controls, were trained on a fixed interval (FI) 40 s schedule, where the first bar‐press response made more than 40 s after a previous reinforcement was rewarded. The decorticates and hippocampals adopted similar patterns of behaviour to the control groups though there were between‐group differences in the details of performance. Compared to controls the hippocampals showed shorter post‐reinforcement pauses and faster overall rates of responding, whilst the reverse was true of the decorticates. Some of this performance difference in the decorticates was attributed to difficulty in retrieving and consuming solid food reinforcement. The performance of the decorticates and hippocampals, as reflected by the post‐reinforcement pause, response distribution and running rate as a function of post‐reinforcement pause duration, suggests that timing remains operational in both groups. The differences in response profiles between the two experimental groups, however, indicate that hippocampus and neocortex probably make independent contributions to performance in this situation. The decorticates and their control group were later transferred from the FI to a response‐independent fixed time (FT) 40 s schedule. Both groups then returned to the former FI 40 s schedule. The decorticates adjusted their behaviour to the different schedules in the same way as the control animals. The results overall are consistent with previous findings that decortication does not abolish normal patterns of operant learning and extends them to include temporal schedules.
A G Protein Mediates the Inhibition of the Voltage‐Dependent Potassium M Current by Muscarine, LHRH, Substance P and UTP in Bullfrog Sympathetic Neurons
Authors: Lopez H. S. , Adams P. R. 
Published: April 2006

AbstractThe involvement of G proteins in the transduction mechanism of M current (Im) inhibition by extracellular ligands in bullfrog sympathetic neurons was examined using the hydrolysis resistant nucleotide analogues GTPγS and GDPβS. Im was recorded in large (40–60 μm) isolated neurons using the patch‐clamp technique in the whole‐cell configuration, as well as in neurons from the intact ganglion impaled with conventional microelectrodes. In whole‐cell recordings Im could be recorded without significant loss for 1 h or more provided ATP was present in the patch pipette. Muscarine, D‐Ala6‐LHRH, substance P and UTP reversibly inhibited Im in isolated control neurons, with full and rapid recovery of the current following agonist washout. Dialysis of isolated neurons with various concentrations of GTPγS (1–100 μM) affected, in a dose‐dependent manner, the recovery of Im after its inhibition by brief agonist application. With 50 μM GTPμS, Im inhibition became completely irreversible. Similarly, the reversibility of Im inhibition by muscarine was reduced or abolished by the iontophoretic injection of GTPμS through a second microelectrode into neurons of the intact ganglion. GTPμS by itself caused a slow, agonist‐independent suppression of Im in dialysed neurons, thus mimicking agonist action. Dialysis of isolated neurons with GDPβS (100—500 μM) attenuated by half or more the magnitude of Im inhibition by agonist as compared to control neurons. In addition, GDPβS attenuated the response of a given neuron to muscarine and D‐Ala6‐LHRH, and caused slow increase of Im, as a function of dialysis time. Incubation (2–72 h, 4–36°C) of isolated neurons or intact ganglions with activated pertussis toxin had no effect on the response to muscarine. Toxin injections to experimental animals were equally ineffective. In contrast to Im, the additional inward current with increase in conductance induced by muscarine and D‐Ala6‐LHRH reversed with agonist washout in GTPγS‐dialysed neurons, although more slowly than in control neurons. The results in this study indicate that a G protein, possibly pertussis toxin‐insensitive, provides a common coupling step linking muscarinic, substance P, D‐Ala6‐LHRH and UTP receptors to the inhibition of M current.
Rostral Cerebellum Originates from the Caudal Portion of the So‐Called ‘Mesencephalic’ Vesicle: A Study Using Chick/Quail Chimeras
Authors: Martinez Salvador , Alvarado‐Mallart Rosa‐Magda 
Published: April 2006

AbstractHomotopic and isochronic transplantations of the right dorsal half of the mesencephalic vesicle have been performed between chick and quail embryos at the stage of 10–14 somites. Analysis of the extension of the graft, by means of the quail nucleolar marker, combined with cytoarchitectonic analysis has disclosed that the transplanted neuroepithelium gives rise to isthmic nuclei and to a portion of rostral cerebellum, in addition to the optic tectum and mesencephalic dorsal grisea. These results show that the rostral portion of the cerebellar primordium is located in the so‐called ‘mesencephalic’ alar plate, thus considerably more rostrally than previously supposed. This has been confirmed by two other types of chimeric embryos resulting from homotopic transplantation of either: (i) the quail right alar plate of the first rhombencephalic vesicle, which gives rise to caudal but not rostral cerebellum in the operated side, or (ii) the right alar portion of a segment of the quail neural tube including both the caudal third of the mesencephalic vesicle and the rostral half of the first rhombencephalic vesicle, which gives rise to the whole hemicerebellum in the operated side. Moreover, in chimeric embryos with transplants restricted to the mesencephalic alar plate, the grafted portion of the cerebellar primordium gives rise both to deep cerebellar neurons and to all types of cortical neurons. Among the quail cortical neurons, the Purkinje cells, although intermingled with host Purkinje cells, are organized, at E18, in a characteristic longitudinal band which is strongly reminiscent of the longitudinal functional and morphological organization of the cerebellum. Other types of quail cortical neurons, that is, Golgi cells, granule cells, and molecular layer interneurons, are also observed within this sagittal band. In addition, quail granule cells and molecular layer interneurons as well as quail glial cells, extend over a larger territory on both sides of the longitudinal band containing quail Purkinje cells and even cross the midline and invade the contralateral hemicerebellum. In all types of chimeric embryos, the proliferation, migration, and differentiation of quail transplanted neurons, both in the isthmic region and in the cerebellum, evolve asynchronously from the host homologous ones, following a more precocious and faster developmental schedule. This asynchrony in the development of grafted and host isthmic and cerebellar homologous areas confirms and extends previous findings concerning the proliferation and migration of quail tectal cells in chick quail chimeric embryos (Senut and Alvarado‐Mallart, 1987).
The Effect of Inhibiting the Calcium Activated Neutral Protease, on Motor Unit Size after Partial Denervation of the Rat Soleus Muscle
Authors: Vrbová G. , Fisher T. J. 
Published: April 2006

AbstractRat soleus muscles were partially denervated by removal of the L5 ventral ramus at either 4 ‐ 6 days or 17 ‐ 19 days. Local application of leupeptin, a potent inhibitor of the calcium activated neutral protease to these operated muscles, resulted in a significantly greater maximal tetanic tension and motor unit size, when compared to untreated partially denervated muscles. This was achieved in the 4 ‐ 6 day operated animals by an increased number of terminals and in the 17 ‐ 19 day old animals by increased number of axonal sprouts that maintain contact with muscle fibres. In both groups of operated animals in the leupeptin treated muscles large numbers of motor units were able to maintain or achieve an expanded territory, whilst the size of the largest motor unit did not appear to be increased.It is proposed that leupeptin exerts its effect by inhibiting the degradative action of the neuronal calcium activated neutral protease on the axonal cytoskeleton. Such inhibition may act to prevent or decrease the degradation of cytoskeletal structures in the nerve terminal, and so provide protection for weak terminals at a synapse and growth cones of sprouting axons following partial denervation.
Is the Capacity for Optic Nerve Regeneration Related to Continued Retinal Ganglion Cell Production in the Frog?
Authors: Taylor J. S. H. , Jack J. L. , Easter S. S. 
Published: April 2006

AbstractIn the central nervous system of fish and frogs, some, but not all, axons can regenerate. Retinal ganglion cells are among those that can. The retinae of fish and frogs produce new retinal neurons, including ganglion cells, for months or years after hatching. We have evaluated the hypothesis that retinal axonal regeneration is obligatorily linked to continued production of new ganglion cells.We used bromodeoxyuridine immunocytochemistry to assess retinal neurogenesis in juvenile, yearling, and 10 year old Xenopus laevis. Retinal ganglion cell genesis was vigorous in the marginal retina of the juveniles, but in the yearlings and the 10 year olds, no new ganglion cells were produced there. Cellular proliferation in the central retina was evident at all three ages, but none of the cells produced centrally were in the ganglion cell layer.Regeneration was examined in vivo by cutting one optic nerve and then, weeks later, injecting the eye with tritiated proline. Autoradiographs of brain sections showed that the optic nerves of all three ages regenerated. Regeneration in vitro was assessed using retinal explants from frogs of all three ages. In all cases, the cultures produced neurites, with some age‐specific differences in the patterns of outgrowth.We conclude that retinal axonal regeneration is not linked obligatorily to maintained neurogenesis.
Saccadic Eye Movements and Gaze Holding in the Head‐Restrained Pigmented Rat
Authors: Chelazzi L. , Rossi F. , Tempia F. , Ghirardi M. , Strata P. 
Published: April 2006

AbstractSpontaneous saccadic eye movements were recorded in seven head‐restrained pigmented rats by means of a phase detection search coil system, both in the light and in the dark. In an illuminated environment, all the rats made numerous spontaneous saccades with an average amplitude of 13.2 deg (±2.2 SD) and a maximal amplitude of 35 deg. In the dark, mean saccadic amplitude was significantly reduced to 9.2 deg (±2.0 SD).Saccadic peak velocity increased linearly as a function of saccadic size, with no saturation at high amplitude values. In the light, peak velocity increase was 32.7 deg/s/deg (±3.5 SD). This value is higher than that described in many other species including man and is similar to that of the monkey. Also saccadic duration increased linearly as a function of size at a rate of 1 ms/deg, which is closer to that of monkey than to that of other species including man. Both peak velocity and duration were not significantly different in the dark from those measured in the light.In the light, following a saccadic gaze shift, the rats were able to maintain a steady eye position for long periods, also at large orbital eccentricities. In the dark, on the contrary, the eye presented a drift towards the central position in the orbit. Such a drift had an exponential‐like time course with a time constant of 1567 ms (±829 SD), a value which is much shorter than that of cat and primates. This indicates that in the absence of a visual input, the rat has a poor gaze holding ability compared to other species.
Organotypic Co‐Cultures of Rat Locus Coeruleus and Hippocampus
Authors: Knöpfel T. , Rietschin L. , Gähwiler B. H. 
Published: April 2006

AbstractSlices from the brainstem at the level of the locus coeruleus and from the hippocampus of 5–7 day old rats were co‐cultured using the roller tube technique. After 2–6 weeks in vitro the co‐cultures were examined with antibodies raised against tyrosine‐hydroxylase (TH). The cultures derived from the brainstem consistently contained a bilateral cluster of TH‐positive neurons with 3–5 long slender dendrites. These neurons typically gave rise to several fine varicose fibres reminiscent of catecholaminergic axons. A morphologically distinct group of TH‐positive neurons was detected in the hippocampal slices. The vast majority of them were located in the subicular region and a smaller number in the CA1/CA3 region of the hippocampal explant. TH‐positive neurons were also present in mono‐cultures of hippocampus or brainstem.In the vast majority of co‐cultures, a variable number of TH‐immunoreactive fibres of neurons derived from the locus coeruleus grew over considerable distances to terminate finally within the co‐cultured hippocampus where they branched to form a diffuse innervation plexus with club‐like endings. Even after several weeks in vitro, TH‐positive fibres could still be seen exploring sites which were not related to their target, including the cell‐free areas surrounding the cultures. Fibres in these outgrowth areas formed whirl‐like endings. TH‐positive fibres arising from neurons located in the hippocampus, on the other hand, did not branch extensively and never projected over long distances.Nerve growth factor had no apparent trophic effect on TH‐positive cells in the hippocampus, the locus coeruleus, or in the co‐cultures.
Intrinsic Organization and Connectivity of Intrastriatal Striatal Transplants in Rats as Revealed by DARPP‐32 Immunohistochemistry: Specificity of Connections with the Lesioned Host Brain
Authors: Wictorin K. , Ouimet C. C. , Björklund A. 
Published: April 2006

AbstractIntrastriatal grafts of tissue obtained from the striatal or neocortical primordia of rat fetuses have been studied with respect to their intrinsic organization and connectivity using antibodies to DARPP‐32 in combination with acetylcholinesterase (AChE) histochemistry, tyrosine hydroxylase (TH) immunocytochemistry, and anterograde and retrograde axonal tracing techniques. The striatal grafts were characterized by distinct patches of DARPP‐32‐immunoreactive neurons, which were identical to the densely AChE‐positive patches stained in adjacent sections from the same specimens. The non‐patch areas possessed only few DARPP‐32‐positive neurons and contained only sparse AChE‐positive fibres. The cortical grafts, by contrast, contained no neurons with clear‐cut DARPP‐32‐positivity and they exhibited a sparse, evenly distributed AChE fibre network, similar to that seen in the non‐patch areas of the striatal grafts.The host dopaminergic afferents, as revealed by TH immunostaining, had grown selectively into the DARPP‐32‐positive patches in the striatal grafts, where they formed a dense terminal network around the DARPP‐32‐positive cell bodies. The non‐patch areas, as well as the cortical grafts, received only sparse TH innervation. By contrast, the host cortical afferents, labelled by Phaseolus vulgaris leucoagglutinin from the host frontal cortex, were seen to extend into both the patch and non‐patch areas of the striatal grafts.Transplant neurons projecting into the host brain were labelled by Fluoro‐Gold injections into the ipsilateral host globus pallidus. These injections labelled large numbers of medium‐sized neurons within the striatal grafts and the vast majority of them (over 85%) were confined to the DARPP‐32‐positive patches. Similar Fluoro‐Gold injections labelled only few graft neurons in the cortical grafts.The results indicate that the striatal grafts are composed of a mixture of striatal and non‐striatal tissue, and that the striatal graft compartment selectively establishes afferent and efferent connections with the host nigro‐pallidal system. These graft connections demonstrate a remarkable specificity in the formation of graft–host connectivity. The results, moreover, suggest that developmental properties of the grafted striatal primordium are retained and expressed in the implanted cell suspension, and that the neuronal systems of the lesioned adult host brain, at least to some extent, remain responsive to growth regulating mechanisms normally operating during ontogenetic development.
Changes in Regional Cerebral Oxidative Metabolism Induced by Tactile Learning and Recognition in Man
Authors: Roland Per E. , Eriksson Lars , Widén Lennart , Stone‐Elander Sharon 
Published: April 2006

AbstractWe measured the regional cerebral oxidative metabolism (rCMRO2) with positron emission tomography in normal healthy volunteers in three different stages: rest, tactile learning, and tactile recognition of complicated geometrical objects. The frequency of manipulatory movements during tactile recognition was twice that of tactile learning. Tactile recognition with the right hand increased rCMRO2 in six prefrontal cortical areas, bilaterally in the supplementary motor areas, the premotor areas and supplementary sensory areas, in the left primary motor and primary sensory area, in the left anterior superior parietal lobule, bilaterally in the secondary somatosensory area, the anterior insula, lingual gyri, hippocampus, basal ganglia, anterior parasagittal cerebellum, and lobus posterior cerebelli. These structures have in other studies been found to participate in manipulatory movements and analysis of somatosensory information. Tactile learning increased rCMRO2 in the same structures as did tactile recognition. Thus we found no differences in the anatomical structures participating in storage and retrieval. However the rCMRO2 increases in the left premotor cortex, supplementary motor area, and left somatosensory hand area were larger during tactile recognition in accordance with the higher frequency of manipulatory movements and higher flux of somatosensory information from the periphery during recognition. Despite this the rCMRO2 was significantly higher in the neocerebellar cortex during tactile learning. Since there were no learning effects on the manipulatory movements, this extra metabolic activity in the lateral cerebellum was attributed to energy demanding processes associated with climbing fibre activity during storage of somatosensory information.