bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrastructural identification of HRP‐injected oligodendrocytes in the intact rat optic nerve
Authors: Ransom Bruce R. , Butt Arthur M. , Black Joel A.
Published: January 2005

Glial cells in the rat optic nerve were visualized by intracellular injections of horseradish peroxidase (HRP). A novel class of cell was encountered that was presumed to be an oligodendrocyte on the basis of arguments related to its light microscopic appearance after intracellular staining (Butt and Ransom, Glia 1989; 2:470–475). These cells had 10–20 parallel processes 200–300 μm long that were oriented exclusively along the long axis of the optic nerve; the parallel processes were connected to the cell body by thin branches 15–30 μm long. To determine if these HRP‐filled cells were oligodendrocytes, they were examined ultrastructurally; all cells examined in this way were unequivocally found to be myelin‐producing oligodendrocytes. The oligodendrocytes contained intracellular organelles that were characteristic of this cell type, including abundant Golgi profiles and microtubules. In addition, HRP was found to fill the inner and outer tongue processes of myelin sheaths and the paranodal loops at nodes of Ranvier, proving that the entire cytoplasmic border surrounding the myelin sheath rapidly communicates by intracellular diffusion with the cell body. This electron microscopic study demonstrates that oligodendrocytes in the rat optic nerve can be positively identified by their distinctive light microscopic appearance after intracellular dye injection, and provides light microscopic criteria for establishing the number, distribution, and dimensions of the myelin segments provided by individual oligodendrocytes.
Tracing glial cell lineages in the mammalian forebrain
Authors: Goldman James E. , Vaysse Pierre J.‐J.
Published: January 2005

Astrocytes and oligodendrocytes emerge in late gestational and early post‐natal development in the mammalian CNS. The nature, and number, of progenitors for each glial type is a central question. This review will focus upon several unresolved issues relating to glial cell lineages and describe new methods to try to illuminate these issues further: (1) How can developmental patterns by which immature neuroectodermal cells give rise to classes of neurons and glia be understood in the context of lineage? (2) What are the lineage relationships among the various cell classes, how many glial lineages are there in the developing CNS, and how can recent methods of clonal analysis using stable markers be used to clarify lineage patterns? (3) Do patterns of gliogenesis vary in different regions of the CNS? (4) How do patterns of gliogenesis observed in vitro relate to those in vivo?.
Cell origin and identity in Limb regeneration and development
Authors: Ferretti Patrizia , Brockes Jeremy P.
Published: January 2005

The occurrence of limb regeneration in adult urodele amphibians raises fundamental questions about the relationship between development and regeneration. The use of monoclonal antibodies as cell markers has provided clear evidence that blastemal cells, the progenitor cells of the regenerate, are not the same as limb bud cells in the embryo. For one of these antibodies the distinction has been traced to the relationship between limb regeneration and the nerve supply. Innervation of the limb bud during development appears to establish nerve‐dependent growth control for regeneration. The cell markers have also contributed to the problem of how the blastemal cells arise after amputation, although several important questions remain to be answered.
Ion channels in cultured adult human schwann cells
Authors: McLarnon James G. , Kim Seung U.
Published: January 2005

Single channel currents have been recorded from cultured adult human Schwann cells. In both cell‐attached and ‐excised (inside‐out) patches, openings from a high‐conductance (360 pS) channel were observed; measurements of the zero‐current potential indicated that the channel was predominantly selective for chloride. Depolarizing and hyperpolarizing voltage steps activated the anion channel, which subsequently reverted to a closed state even in the presence of the maintained step. A second channel, with a conductance near 20 pS and with a current amplitude that increased with patch hyperpolarization, passed inward K+ currents in both cell‐attached and inside‐out patches. The mean open times for this channel were near 20 ms at the cell resting potential and decreased with patch hyperpolarization. The presence of these anion and cation selective channels in the human Schwann cell membrane would be consistent with a role for the cells in the regulation of extracellular K+.
Isolated growth cones stimulate proliferation of cultured Schwann cells
Authors: Dent Erik W. , Ida James A. , Yoshino Jun E.
Published: January 2005

A growth cone‐enriched fraction was prepared from 3–4 day rat cerebra. Examination of the growth cone fraction by electron microscopy revealed numerous structures circular in appearance that contain a number of features common to neuronal growth cones in vivo. The isolated growth cones stimulated a dose‐dependent incorporation of [3H]‐thymidine into cultured Schwann cells in a manner similar to that observed with an axolemma‐enriched fraction prepared from adult rat brainstem. The mitogenic activities of both the growth cone fraction and axolemma‐enriched fraction were decreased 50% and 20%, respectively, by treatment with heparitinase I. The mitogen for Schwann cells present in the isolated growth cones appears to be similar to that found in axolemma‐enriched fractions prepared from adult rats.
Activation of endothelin receptors by sarafotoxin regulates Ca2+ homeostasis in cerebellar astrocytes
Authors: Holzwarth James A. , Glaum Steven R. , Miller Richard J.
Published: January 2005

We carried out experiments designed to investigate the effects of sarafotoxin‐6B (SFTx) on [Ca2+]i in cerebellar astrocytes using the Ca2+ indicator fura‐2. Both endothelin‐1 and sarafotoxin‐6B increased [Ca2+]i in individual cerebellar astrocytes in cell culture. The shape of the response was variable but usually consisted of an initial peak of [Ca2+]i followed by an extended plateau increase in [Ca2+]i. In Ca2+‐free medium only the initial peak was observed. If Ca2+ was subsequently readmitted to the external medium a plateau was now formed. When external Ca2+ was removed during a plateau, [Ca2+]i rapidly declined; replacing the external Ca2+ reversed this decline. The plateau was also reversibly reduced by addition of Ni2+ (5 mM) to the external medium. Addition of 50 mM K+ produced a small increase in [Ca2+]i in most cells. This response was blocked by nimodipine. However, nimodipine only slightly blocked the plateau increase in [Ca2+]i that was formed following activation of endothelin receptors. Furthermore, perfusion of cells with 50 mM K+ during the plateau portion of a response to SFTx reduced [Ca2+]i. In some cells addition of a phorbol ester produced a sustained increase in [Ca2+]i that was blocked by nimodipine. In conclusion, activation of endothelin receptors by SFTx in cerebellar astrocytes produces both Ca2+ mobilization and Ca2+ influx. The pathway for Ca2+ influx is predominantly a non‐voltage‐dependent one, although some entry through a dihydropyridine‐sensitive pathway also appears to occur. Furthermore, activation of protein kinase C in cerebellar astrocytes activates voltage‐sensitive Ca2+ channels. © 1992 Wiley‐Liss, Inc.
Protein kinase C isoforms in human glioblastoma cells
Authors: Misra‐Press Anita , Fields Alan P. , Samols David , Goldthwait David A.
Published: January 2005

Protein kinase C (PKC), an enzyme involved in signal transduction, responds to diacyl glycerol and also to phorbol ester, a ligand analogous to diacyl glycerol. We have studied the expression of the major isoforms (α, βI, βII, and γ) in eight human glioblastoma cell lines. In all eight lines, PKC‐α mRNA and protein were expressed. In none of the eight did a probe for PKC‐βI and ‐βII mRNA give positive results nor were Western blots for PKC‐βII positive. The half‐life for PKC α mRNA was approximately 16 h and levels of the mRNA were increased slightly following addition of phorbol myristate acetate (PMA) or transforming growth factor‐beta (TGFβ). PKC‐γ was present in most of the glioblastomas. In cell line A172, 82% of the PKC‐α was present in the cytosol with the remainder evenly divided between plasma membrane and nucleus. Thirty minutes after addition of PMA, 33% of the total original protein was in the plasma membrane and 48% in the nuclear fraction. By 21 h, no PKC‐α was recovered from any fraction. PKC‐γ was also down‐regulated in the presence of PMA, but there was no evidence for translocation to the plasma membrane or nuclear fraction. In a more detailed study, translocation of PKC‐α in the presence of PMA was complete by 10 min, and a major decrease in the PKC translocated to the plasma‐membrane fraction occurred some time between 2 and 4 h after PMA addition, while a major decrease in the translocated nuclear fraction occurred some time after 6 h. cAMP alone had no effect on the PKC α protein level or distribution, nor did it alter the translocation and down‐regulation due to PMA exposure. In these studies the level of PKC‐α mRNA in tumors was similar to that in normal glial cells. © 1992 Wiley‐Liss, Inc.
Interleukin‐1β regulates proenkephalin gene expression in astrocytes cultured from rat cortex
Authors: Negro Alessandro , Tavella Adriana , Facci Laura , Callegaro Lanfranco , Skaper Stephen D.
Published: January 2005

Glial cells execute essential functions in central nervous system (CNS) development and are also believed to play important roles during gliosis in response to trauma or disease. These developmental and pathological states have also been associated with elevated expression of opioid genes. Because levels of the cytokine interleukin‐1β (IL‐1β) increase following CNS lesions, we examined the possible influence of IL‐1β on the expression of opioid genes in astrocytes cultured from rat cortex. Proenkephalin mRNA expression was stimulated by IL‐1β in a time‐ and concentration‐dependent manner, being maximal with 5 U/ml IL‐1β at 4h. Although the β‐adrenergic agonist isoproternol was also active, interferon, glutamate, and carbacol were not. Unlike isoproterenol, the actions of IL‐1β were not associated with a cyclic adenosine monophosphate (AMP)‐dependent pathway. Interleukin‐1β also regulated a proenkephalin‐chloramphenicol acetyltransferase fusion gene transiently transfected into astrocytes, with a dose‐response similar to that active in proenkephalin mRNA. These effects of IL‐1β were region‐specific, not being observed with either cerebellar or hippocampal astrocytes; however, isoproterenol was active in the latter cell populations. Proenkephalin mRNA in cortical astrocytes was stimulated following a temperature stress. These results suggest that enhanced proenkephalin gene expression in astrocytes by IL‐1β may be important in neuroimmune interactions and in trauma‐induced CNS injury or stress. © 1992 Wiley‐Liss, Inc.
Functional properties of retinal Müller cells following transplantation to the anterior eye chamber
Authors: Small Rochelle K. , Watkins Brynmor A. , Munro Peter M. , Liu Dandan
Published: January 2005

Two types of glial cells occur in the retina, Müller cells and astrocytes. These cells share several structural features such as extending endfeet onto blood vessels of the retina. Retinal vessels express a tight blood‐retinal barrier which is comparable to the blood‐brain barrier (BBB) of the CNS. While astrocytes have been implicated in the induction of the BBB, the role of Müller cells in the blood‐retinal barrier is unknown. To determine if Müller cells are capable of influencing vascular permeability, we have prepared Müller cells that are free of astrocytes and transplanted them to a peripheral target, the anterior eye chamber. Müller cells were identified 2 weeks to 3 months after injection and were predominantly localized within the connective tissue of the ciliary body. The Müller cells occurred as dense clusters of cells closely associated with ciliary blood vessels. The ciliary vessels adjacent to Müller cells were freely permeable to circulating horseradish peroxidase (HRP), suggesting that Müller cells did not induce tight barrier properties from these leaky peripheral vessels. In contrast, cortical astrocytes injected into the anterior eye chamber preferentially formed a monolayer on the anterior surface of the iris, a region known to contain blood vessels that are impermeable to circulating tracers (e.g., Raviola, Exp Eye Res [Suppl] 25:27, 1977). Müller cells were rarely associated with the iris and the few cells that were present were located deep within the iris stroma rather than on the surface. The behaviour of guinea pig Müller cells transplanted to the anterior eye chamber contrasts sharply with that of cortical astrocytes in terms of: (1) the ocular compartment to which Müller cells migrate; (2) the tissue invasiveness of the cells; and (3) the degree of permeability of blood vessels adjacent to transplanted cells. The results of this study emphasize the functional distinctness of the two types of retinal glia and suggest that Müller cells from guinea pig retina may not be active in modifying the permeability properties of peripheral blood vessels, a function that has been suggested for astrocytes.
Interleukin‐1 and tumor necrosis factor‐mediated regulation of C3 gene expression in human astroglioma cells
Authors: Barnum Scott R. , Jones Jennifer L. , Benveniste Etty N.
Published: January 2005

In this report, we show that in the human astroglioma cell line D54‐MG, both interleukin‐1 (IL‐1β) and tumor necrosis factor‐alpha (TNF‐α) enhance C3 gene expression in a time‐ and dose‐dependent manner. Kinetic analysis demonstrates that after 96 h, C3 mRNA levels increase approximately 30‐fold and 20‐fold in response to IL‐1β or TNF‐α, respectively. C3 protein production increases proportionally, reaching levels 36‐fold and 18‐fold higher than untreated controls upon exposure to IL‐1β or TNF‐α, respectively. D54‐MG cells require a minimal 1 h exposure to IL‐1β in order to enhance C3 gene expression significantly, while 4 to 8 h are required for TNF‐α. Simultaneous treatment of D54‐MG cells with IL‐1β and interferon‐gamma (IFN‐γ) resulted in an additive increase in both C3 mRNA and protein expression, a finding not seen with the combination of TNF‐α and IFN‐γ. Primary rat astrocytes also express increased C3 mRNA levels after 48 h in response to IL‐1β (5.3‐fold increase) and TNF‐α (7‐fold increase), while an additive effect was observed upon simultaneous treatment with both IL‐1β and IFN‐γ. In the central nervous system (CNS), endogenous complement and cytokine production by astrocytes, and enhancement by IFN‐γ, a product of activated T cells often seen in the CNS in neural autoimmune disease, may contribute to the pathogenesis of inflammatory demyelinating diseases such as multiple sclerosis.
Infusion of cytosine‐arabinoside into the cerebrospinal fluid of the rat brain inhibits the microglial cell proliferation after hypoglossal nerve injury
Authors: Svensson Mikael , Aldskogius Håkan
Published: January 2005

The present study describes a method to inhibit selectively the microglial cell proliferation following peripheral nerve injury. Continuous infusion of cytosine‐arabinoside (ARA‐C) from an osmotic minipump to the fourth ventricle or cisterna magna completely blocks the proliferation of microglial cells that normally occurs following hypoglossal nerve transection. This treatment had no significant effect on other glial cells or on the expected morphological changes in the axotomized hypoglossal motorneurons. The method opens up new possibilities for analyzing the functional role of the axotomy‐induced microglial cell reaction.
Extracellular matrix modulates the proliferation of rat astrocytes in serum‐free culture
Authors: Nagano Nobuhisa , Aoyagi Masaru , Hirakawa Kimiyoshi
Published: January 2005

The mechanism of glial proliferation in the developing nervous system, as well as in response to injury, inflammation, and tumor invasion, is unknown. Several growth factors and extracellular matrices have been shown to stimulate the proliferation of cultured cells of various origin, including astrocytes. We investigated the effect of extracellular matrix components, including fibronectin (FN), laminin (LN), and collagen types I and IV, on the growth of astrocytes during stimulation by various growth factors. When astrocytes were grown on FN‐ and LN‐coated wells in a serum‐free, chemically defined medium, their increase in number significantly exceeded that of cells grown on plastic wells. The addition of platelet‐derived or basic fibroblast growth factor to cells cultured on FN ‐ or LN ‐coated wells significantly potentiated astrocyte proliferation. The collagen preparations had no such effect. These observations indicate that FN and LN have a fundamental part in converting the quiescent astrocyte into the proliferating phenotype, which may be required for remodeling damaged brain tissues in vivo. © 1993 Wiley‐Liss, Inc.
Differential expression of carbonic anhydrase isozymes in microglial cell types
Authors: NóGrádi Antal
Published: January 2005

Microglial cells have been shown to express carbonic anhydrase. Using carbonic anhydrase histochemistry and immunohistochemistry, different types of cen‐tral nervous system microglial cells were detected, which expressed two main carbonic anhydrase (CA) isozymes during the early postnatal stage of development and after peripheral nerve injury in the spinal cord of adult rats. Amoeboid and reactive microglial cells were heavily immunostained for CA‐II and CA‐III and showed colocalization with complement receptor type 3 and Griffonia Simplicifolia B4 isolectin. Resting microglial cells in the brain and spinal cord showed faint CA‐III staining and were negative for CA‐II. These results show that not only CA‐II, but also CA‐III isozyme is represented in the central nervous system and carbonic anhydrase activity may correlate with metabolic and immunological changes of microglial cells. These data also further strengthen the idea of the mesodermal origin of central nervous system macrophages. © 1993 Wiley‐Liss, Inc.
Migration of newly generated neurons upon ependymally derived radial guide cells in explant cultures of the adult songbird forebrain
Authors: Goldman Steven A. , Lemmon Vance , Chin Steven S.‐M.
Published: January 2005

The adult songbird forebrain undergoes neuronal production through‐out adulthood, with the production of new neurons in discrete regions of the neostriatal ventricular zone. Upon mitogenesis, these new neurons migrate into the subjacent brain parenchyma along radially directed guide fibers. In long‐term ventricular zone explant cultures, derived from the higher vocal center of the adult canary, newly migratory neurons were found to associate preferentially with a characteristic substrate cell type. These small, parvonuclear substrate cells formed tightly packed epithelioid sheets, in which ciliated ependymal cells were common, as recognized by both live observation and electron microscopy. A subpopulation of these cells was immunostained by monoclonal antibody 3A7, which preferentially stains the guide fiber network of the adult avian brain. These 3A7+ cells included ependymal cells and bipolar radial cells, as well as morphologically defined astrocytes. As they matured in vitro, the 3A7+ bipolar radial cells extended long, unbranching fibers, which ultimately traversed the culture substrate. Like ependymal cells, they supported neuronal migration. These cells were likely homologous to radial guide cells in vivo. Thus, neuronal migration in adult avian forebrain culture occurred upon guide cells of ependymal derivation. © 1993 Wiley‐Liss, Inc.
Interleukin‐6 production by brain tissue and cultured astrocytes infected with Theiler's murine encephalomyelitis virus
Authors: Rubio Nazario , Sierra Angeles
Published: January 2005

Theiler's murine encephalomyelitis virus (TMEV) is known to interact with cells of the central nervous system (CNS). Here we report that, interestingly, it is a potent inductor of interleukin‐6 (IL‐6) in the CNS of infected animals and in pure cultures of astrocytes. Maximal IL‐6 gene transcription in glial cells, as detected by bioassay and ELISA, was observed at 6 and 24 h after infection. Astrocytes from both SJL/J and Balb/c (strains of mice susceptible and resistant, respectively, to TMEV‐induced demyelination) produced similar amounts of IL‐6, measured in tissue culture supernatants. These results indicate that although an immunomodulatory effect can be exercised by IL‐6 synthesized by astrocytes, it does not play a crucial role in immune‐mediated demyelination induced by TMEV. © 1993 Wiley‐Liss, Inc.
Interactions of living astrocytes in vitro: Evidence of the development of contact spacing
Authors: Dreher Zofia , Tout Simon , Stone Jonathan
Published: January 2005

We have studied the behaviour of living, process‐bearing astrocytes in vitro, observing groups of cells at daily intervals for up to 7 days. Each cell initially formed two processes, appearing bipolar in shape, and with further time in culture, grew additional processes and appeared stellate. As their processes grew, the interactions between astrocytes underwent characteristic changes. While bipolar, the cells appeared to avoid making contact, lying parallel to each other. As they became stellate, the astrocytes made extensive contact with neighbours, gradually forming extended, contacting networks in which their somas were regularly spaced (as previously described). The interactions which led to the establishing of such arrays were also evident. If two cells were initially close or adjacent, they extended short processes to contact each other; then, as their processes grew, their somas moved apart, until they were separated by 60‐120 μm. If two cells were initially well separated, each directed processes towards the other until contact was made, often with striking precision, and their somas then moved together, until they were separated by 60‐120 μm. These behaviours of contact, separation, and approach caused astrocytes to form clusters, within which their somas appeared regularly spaced, and may represent the interactions which occur among astrocytes during normal development to produce the regularly spaced arrays of astrocytes described in earlier studies of intact central nervous tissue. © 1994 Wiley‐Liss, Inc.
Glial hypertrophy is associated with synaptogenesis following motor‐skill learning, but not with angiogenesis following exercise
Authors: Anderson Brenda J. , Li Xiangchun , Alcantara Adriana A. , Isaacs Krystyna R. , Black James E. , Greenough William T.
Published: January 2005

Rats reared from weaning in a complex environment have an increase in (1) glial surface area, (2) capillary volume, and (3) the number of synapses, per neuron. In that paradigm it has not been possible to determine whether the glial increase more closely correlates with the increase in synaptic numbers or with angiogenesis. More recently we have found that rats that exercised had an increase in the density of capillaries without an increase in the synaptic numbers, whereas rats that learned new motor skills had a greater number of synapses per neuron without an increase in the density of capillaries. Those findings provided the opportunity to investigate whether changes in glial volume in the cerebellum correspond to changes in the number of synapses or in capillary volume. Glial area fraction estimates were obtained using point counts on electron micrographs from the previous studies. The skill learning group had a greater volume of molecular layer per Purkinje cell, and also a greater volume of glia per Purkinje cell, than rats in either an inactive group or rats in two exercise groups. No significant differences were found in glial volume per synapse and glial volume per capillary across groups, although there was a tendency for glial volume per capillary to be lower in the exercise groups. The data indicate that glial volume correlates with synaptic numbers and not with capillary density. © 1994 Wiley‐Liss, Inc.
A one‐year prognosis of dysthymic disorder and major depression in old age
Authors: Kivelä Sirkka‐Liisa , Pahkala Kimmo , Laippala Pekka
Published: January 2005

A prospective follow‐up of 199 elderly (60 + yr) patients (65 men and 134 women) suffering from dysthymic disorder and 42 elderly (60 + yr) patients (13 men and 29 women) suffering from major depression is described. The mean duration of the follow‐up was 15.3 ± 4.3 months for dysthymic men, 15.2 ± 4.4 months for dysthymic women, 15.3 ± 4.0 months for major depressive men and 14.0 ± 4.2 months for major depressive women. Forty‐three per cent of the dysthymic men, 38% of the dysthymic women, 39% of the major depressive men and 48% of the major depressive women had a good outcome. In dysthymic men, few visiting contacts were associated with poor outcome. In dysthymic women, poor outcome was associated with many depressive symptoms, low social participation, not living alone, low self‐perceived health, intensive diurnal variation of symptoms, low interest in work and activities, low sexual interest, and hypochondrial and compulsive symptoms. In major depressive men, no variable was associated with outcome. In major depressive women, poor outcome was associated with diabetes mellitus, suicidal ideas or attempted suicide, and psychomotor agitation or psychomotor retardation.
Dependency in old age: A comparison of mental and physical factors
Authors: Kay D. W. K. , Holding T. A. , Jones B. , Littler S.
Published: January 2005

The lavel of dependency of 412 patients aged 70 years or over living in hospitals, nursing homes or sheltered accommodation (N=312) or receiving care from the domiciliary nurising services (N=100) and of 100 elderly people living in the community in Hobart, Tasmania, was assessed using a version of the CARE schedule. Therespective roles of mental and physical factors were examined using other CARE intems and after administering the Geriatric Mental Status schedule and the Wechsler Memory Scale. Rank‐order correlations and log‐linear analyses indicated that physical impairment affecting mobility and upper limb function and cognitive impairment due to dementia were about equally strongly related to the level of dependency;at least moderate degrees of both mental and physical impairment were present in 20% of patients. Vision was often hard to assess in demented patients but was associated with dependency in the non‐demented. Dependency was significantly related to age and self‐rated healthbut not to deafness and was related to mood disorder only in non‐demented patients nursed at home. Apart from this, these patients showed similar relations between dependency and physical and mental impairments to those living in institutions. Central nervous system disease was associated with greater dependency than other medical diagnoses. Preventative programmes, and effective management and treatment of the individual, will depend on careful diagnosis of the causes ofdependency.
Different influence of backward masking on visual pattern recognition in the early stages of presenile dementia and normal ageing
Authors: Müller Gottfried , Weisbrod Steffen , Klingberg Fritz
Published: January 2005

The effect of backward masking with illumination of all fields or with a checkerboard pattern, respectively, on the recognition of pattern + or T was measured on four groups of subjects: 21 presenile onset DAT patients, 16 patients with a questionable vascular dementia of the same age (CVD group), 15 age‐matched control subjects (EC group) and 16 younger control subjects (YC group, mean age 22 years). The pattern stimulus had a duration of 20 ms and was followed by the masking stimulus pattern (20 ms duration) with increasing intervals in steps of 5 ms. The mean recognition threshold (RT) for each of the four possible pattern–mask combinations was measured in five trials. The RTs decreased within the five trials in all groups. DAT patients and CVD patients adapted with different speeds during the five trials. We found a small significant RT difference between elder and younger control subjects, whereas patients had increased RTs in the first trial and differences in the four variants in the further trials compared with age‐matched controls. The test contributes to a set of data for diagnosis and differential diagnosis in the early stages of presenile dementia.
Liver tissue engineering at extrahepatic sites in mice as a potential new therapy for genetic liver diseases
Authors: Ohashi Kazuo , Waugh Jacob M. , Dake Michael D. , Yokoyama Takashi , Kuge Hiroyuki , Nakajima Yoshiyuki , Yamanouchi Masaki , Naka Hiroyuki , Yoshioka Akira , Kay Mark A.
Published: January 2005

Liver tissue engineering using hepatocyte transplantation has been proposed as an alternative to whole-organ transplantation or liver-directed gene therapy to correct various types of hepatic insufficiency. Hepatocytes are not sustained when transplanted under the kidney capsule of syngeneic mice. However, when we transplanted hepatocytes with the extracellular matrix components extracted from Engelbreth-Holm-Swarm cells, hepatocytes survived for at least 140 days and formed small liver tissues. Liver engineering in hemophilia A mice reconstituted 5% to 10% of normal clotting activity, enough to reduce the bleeding time and have a therapeutic benefit. Conversely, the subcutaneous space did not support the persistent survival of hepatocytes with Engelbreth-Holm-Swarm gel matrix. We hypothesized that establishing a local vascular network at the transplantation site would reduce graft loss. To test this idea, we provided a potent angiogenic agent before hepatocyte transplantation into the subcutaneous space. With this procedure, persistent survival was achieved for the length of the experiment (120 days). To establish that these engineered liver tissues also retained their native regeneration potential

in vivo
, we induced two different modes of proliferative stimulus to the naïve liver and confirmed that hepatocytes within the extrahepatic tissues regenerated with activity similar to that of naïve liver.
In conclusion,

our studies indicate that liver tissues can be engineered and maintained at extrahepatic sites, retain their capacity for regeneration

in vivo
, and used to successfully treat genetic disorders. (Hepatology 2005;41:132–140.)
Comparison of zopiclone and flurazepam treatments in insomnia
Authors: Singh Amarendra N. , Bourgouin Jean
Published: January 2005

In this double‐blind study the efficacy and safety of two doses (7·5 and 11·25 mg) of zopiclone were compared to that of flurazepam (30 mg) in 60 insomniac patients divided into three groups. After an initial 4‐day washout period, placebo was administered single‐blind to all patients followed by 24 consecutive days of either one of the three drug levels. No significant difference was shown between the two zopiclone dosages at any time during the study for sleep efficacy and psychomotor performance. Compared to flurazepam, zopiclone was slightly less effective for sleep induction and sleep soundness variables. However, flurazepam was constantly worse than zopiclone for daytime performance. This study shows that both zopiclone dosages are shown to be active and safe in the treatment of insomnia, and exhibit a true advantage over flurazepam by its low incidence of residual effects.
Reported neurotoxicity with the lithium/haloperidol combination and other neuroleptics—A literature review
Authors: Batchelor D. H. , Lowe M. R.
Published: January 2005

A literature review identified 33 case reports of neurotoxicity following combined treatment with lithium and haloperidol. The reports were assessed using criteria previously proposed as offering explanations for the clinical effects noted: lithium toxicity, uncertainties concerning the diagnoses and clinical management of some of the patients, and the probable involvement of the neuroleptic malignant syndrome.

The presence of a true lithium/haloperidol interaction, or indeed any true interaction between lithium and neuroleptics, cannot readily be demonstrated from the data available. The combined use of lithium and haloperidol would appear to be relatively safe when serum lithium levels are maintained below 1·0 mmol/1.
Moclobemide pharmacokinetics in depressed patients: Lack of age effect
Authors: Maguire K. , Pereira A. , Tiller J.
Published: January 2005

The pharmacokinetics of moclobemide were examined in 19 depressed patients following a single oral dose of 50 mg. Ten patients were aged >60 years and nine <59 years. Plasma concentrations were analysed by gas chromatography with nitrogen‐specific detection. Pharmacokinetic parameters calculated were peak concentration, time to reach the peak, terminal disposition half‐life, area under the curve, oral clearance and apparent volume of distribution. No clinically significant differences were found betwen the two patient groups for these parameters. Thus there is no requirement for dosage adjustment in the older patient for moclobemide. This contrasts with some tricyclic and tetracyclic antidepressants which show significant age effects. Further studies of moclobemide for the treatment of elderly depression are warranted.
The effect of olfactory bulbectomy in the rat, alone or in combination with antidepressants and endogenous factors, on immune function
Authors: Song Cai , Leonard B. E.
Published: January 2005

The results from studies in the olfactory bulbectomized (OB) rat model of depression clearly show that the changes in the immune system following bulbectomy are similar to those reported in depressed patients. For example, mitogen‐stimulated lymphocyte proliferation and neutrophil phagocytosis are reduced while monocyte activity is elevated. In the differential white cell (WBC) count, the percentage of neutrophils is increased and the lymphocytes is decreased. In addition, an increase in some of positive acute phase proteins and a decrease in negative actue phase protein albumin are also found in OB rats.

The antidepressants, such as serotonin reuptake inhibitors (fluvoxamine and sertraline), the antihistamine terfenadine, the cytokine IL‐2 and neuropeptide Y, which normalize both the brain noradrenergic and serotonergic system, attenuate the hyperactivity of OB rats in both the ‘open field’ and the open arms of the elevated plus‐maze, and reverse the suppression in both lymphocyte proliferation and neutrophil phagocytosis. Antidepressants (desipramine and lithium) which have been shown to normalize the noradrenergic and/or dopaminergic system in OB rats, significantly reverse the hyperactivity of OB rats in the ‘open field’ and the reduced neutrophil phagocytosis. However, most of these antidepressants and endogenous factors fail to normalize the abnormalities in the WBC count. Thymopeptide treatment normalizes the WBC count, the changes in the noradrenergic and serotonergic systems and lymphocyte proliferation but fails to attenuate the hyperactivity in OB rats. The action of thymopeptides on the immune system is direct, while antidepressants and other agents may indirectly affect the immune systems, via neurotransmitters and cytokines. The results from these studies also demonstrate the causal relationship between endogenous factors (such as the thymopeptides, NPY, IL‐2), the sigma ligand JO 1784 and depression.
RD114‐pseudotyped retroviral vectors kill cancer cells by syncytium formation and enhance the cytotoxic effect of the TK/GCV gene therapy strategy
Authors: Germain E. , Roullin V.‐G. , Qiao J. , de Campos Lima P. O. , Caruso M.
Published: January 2005

Background

Wild‐type RD114 virus is capable of generating syncytia during its replication, and it is believed that cell‐free viruses direct the fusion of neighboring cells. The RD114 envelope (Env) that mediates this fusion event is now widely used to pseudotype retroviral and lentiviral vectors in gene therapy. Indeed, vectors pseudotyped with RD114 Env are very efficient to transfer genes into human hematopoietic cells, and they are resistant to human complement inactivation. In this study, we have tested the potential of RD114‐pseudotyped vectors produced from the FLYRD18 packaging cell line to induce syncytia.

Methods

RD114‐pseudotyped vectors produced from the FLYRD18 packaging cells were added on tumor cell lines, and the formation of syncytia was assessed by microscopy after cell fixation and methylene blue staining. The kinetics of syncytium formation was analyzed by time‐lapse microscopy. Finally, the cytotoxic effect of RD114‐pseudotyped vectors was measured by the MTT assay on tumor cells, and in combination with the TK/GCV strategy.

Results

We have found that these vectors were able to mediate cell‐to‐cell fusion of human tumor cell lines. A few hours after addition of the vector, cells started to aggregate to form syncytia that eventually evolved toward cell death 48 h postinfection. RD114‐pseudotyped vectors were very efficient at killing human cancer cells, and they were also able to enhance dramatically the cytotoxic effect of the TK/GCV strategy.

Conclusions

These findings indicate that RD114‐pseudotyped vectors used alone, or in combination with a suicide gene therapy approach, have great potential for the treatment of cancer. Copyright © 2004 John Wiley & Sons, Ltd.
Evidence for differential function of neuronal and glial cell in protein metabolism and amino acid transport
Authors: Hamberger Anders , Babitch Joseph A. , Blomstrand Christian , Hansson Hans‐Arne , Sellströ Åke
Published: January 2005

Amino acid incorporation in neuronal and glial cells has been investigated in several laboratories employing bulk‐separation techniques to obtain cell‐enriched fractions. The relative rates of incorporation into the proteins of both cell types vary substantially with the method of isotope administration. Through the use of single‐pulse perfusions with a duration of 30–40 sec the early time course of labeling has been studied. The difference between neuronal and glial cells with respect to indicating cell interactions will be discussed. The in vitro amino acid incorporation has been measured in neurons and glia after slice incubation. In material from animals developing experimental allergic encephalitis the rate of 3H‐leucine incorporation more than doubles in the unfractionated brain. Glial cells increased their rate of incorporation by approximately 400%under the same conditions. The involvement of specific proteins in the cells and organelles has been studied by gel electrophoresis. The high uptake capacity of glial cells for certain amino acids with possible transmitter functions has been further characterized. The release of these substances is measured in a superfusion system where beds of cells, preloaded with the labeled substance, are used. High potassium pulses stimulate release of, for example GABA in both neuronal and glial cells.
Alterations of central nervous system protein synthesis in response to spinal cord hemisection
Authors: Luttge William G. , Mannis Mark J. , Bernstein Jerald J.
Published: January 2005

This investigation explores the central nervous system protein‐synthetic responses to hemisection of the spinal cord. Adult male rats hemisected at mid T2 were given intravenous injections of 14C‐leucine at 0, 7, 30, or 70 days postoperative. Four hours later the T1, T2, T3, and C6 segments of the spinal cord and right and left samples of somatomotor and occipital cortex were removed, weighed, and frozen. These samples were later homogenized ad subjected to trichloroacetic acid (TCA) separations. Protein‐synthetic activity was expressed as the ratio of the specific activity of the TCA precipitable proteins to the specific activity of the TCA free amino acid pool.

In the spinal cord samples protein‐synthetic activity was greater than in controls at 7 and 30 days postoperative in the T2 segment and at 30 days postoperative in the C6 and T3 segments. In the cortical samples protein‐synthetic activity was greater than in controls in the right and left somatomotor somatomotor cortex at 70 days postoperative. Thus, T2 hemisection leads to initial increases and subsequent decreases in protein‐synthetic activity in both spinal cord and somatomotor cortex. These results are discussed in terms of possible regenerative neural reactions occurring in the central nervous system following spinal cord injury.
Central adrenergic neurons in DOCA‐salt hypertension
Authors: Lamprecht Friendhelm , Jacobowitz David M. , Richardson J. Steven , Kopin Irwin J.
Published: January 2005

The effects of various doses of 6‐hydroxydopamine(6‐OHDA) injected into the hypothalamus on DOCA‐salt‐induced hypertension were studied. The development of hypertension was prevented in the group treated with the highest dose of 6‐OHDA, and the onset of hypertension was delayed in a dose‐dependent fashion in the groups treated with the lower doses of 6‐OHDA. Catecholamine histofluorescence observations showed that the cannula tips placed the drug lateral to the third ventricle. The most prominent change observed was a marked unilateral reduction in the fluorescence of the dopaminergic nerves of the caudate‐putamen and in the number of cell bodies in the substantia nigra. These results suggest possible sites of central aminergic control of blood pressure.
Neurochemical changes in the cat's spinal cord due to orthodromic tetanic stimuli. I: Phospholipids
Authors: Althasu H.‐ H. , Neuhoff V. , Haase J. , Ross H.‐G.
Published: January 2005

Posttetanic potentiation of monosynaptic reflexes has been used as a paradigm for neuronal plasticity. The explanation for this phenomenon is an increased responsiveness of the synaptic junctions. This would basically required chemical changes of the nervous structures involved. The ventral horn area of the spinal cord was therefore analyzed neurochemically. The determination of the phospholipids revealed an alteration of their composition. Sphingomyelin, phosphatidylcholine and phosphatidylinositide/serine behaved differently, whereas phosphatidylethanolamine and the total phospholipid content remained unchanged.
Consummatory behavior as a function of ambient temperature in septal‐lesioned and control rats
Authors: Sanes J. , Donovick P. J. , Burright R. G.
Published: January 2005

Septal lesions or control operations were produced in male and female rats. Measurements of water and food consumption were carried out while the rats were housed under warm vivarium temperatures (24°C) and when maintained in a cold room (6°C). Examination of the data from the entire week spent in the cold revealed that rats with septal lesions deviated from precold water‐consumption levels less than comparable control rats. Further, whereas rats with septal lesions suppressed intake for the first 24 hr following either shift in environmental temperatures, control animals inhibited drinking only when returned to the warm environment. Both surgical groups elevated food consumption in the cold. The relative amount of food and water consumed during the day (vs night) increased for all groups when maintained in the cold. Differences in degree of reactivity to the manipulations were observed in male and female rats. These findings were interpreted as adding further support to our contention that septal lesions alter the behavior (rather than direct metabolic) adaptations an animal makes to its environment.
Single‐cell responses associated with rhythmic slow‐wave potentials in rat superior colliculi
Authors: Anderson Kenneth V. , O'Steen W. Keith
Published: January 2005

The present study was designed to investigate the features of rhythmic slow‐wave potentials in the superior colliculi of rats and to study the relationship between these potentials and the activity of single collicular neurons. In contrast to studies in other portions of the visual system, rhythmic slow‐wave potentials in the colliculi fell within a single limited range of frequencies from 9 to 26 cycle/sec. Single‐cell recordings revealed that numerous collicular neurons were also responding rhythmically, with discharge frequencies generally coinciding with those established for collicular slow‐wave potentials. In some animals slow‐wave and single‐cell potentials were recorded simultaneously through adjacent electrodes, and in all instances the frequency of discharge of single neurons coincided with the frequency of oscillation of the slow‐wave potentials. These data suggest the rhythmic postsynaptic potentials in individual collicular neurons may be the mechanism by which rhythmic slow‐wave potentials are generated.
Binding of γ‐aminobutyric acid and taurine to synaptosomal fractions of regions of the feline CNS
Authors: Gadea‐Ciria Manuel , García‐Gracia Manuel , Camacho Juan Gervas , Somoza Gene , Balfagón Gloria , DeFeudis Francis V.
Published: January 2005

The “binding” of 3H‐γ‐aminobutyric acid (3H‐GABA) and 14C‐taurine (7 × 10−5M) to synaptosomal fractions of the feline CNS was studied using differential centrifugation and double‐isotope methods. Of the regions examined, the “binding” of GABA (in nmole /mg protein) occurred to the greatest extent, in cerebral cortex, olfactory bulb, and colliculi and, to a lesser extent, in caudate nucleus, corona radiata, and fornix. Distribution ratios revealed that GABA binding was greater in the cerebral cortex than in caudate nucleus, brain stem, spinal cord, and white matter regions. The binding of taurine (in nmole/mg protein) was lowest in cerebral cortex and highest in brain stem and spinal gray regions. Distribution ratios for taurine indicated that its accumulation was similar in all CNS regions studied, except for slightly higher values for cerebellar cortex and fornix. These results indicated that preferential binding of both GABA and taurine exists among regions of the feline CNS.
A psychoneural model of visual contrast
Authors: Hirsch Henry R. , Gibson John M.
Published: January 2005

A typical set of visual contrast data can be described by a function which relates brightness responses to the luminance stimulus provided by a target that is viewed against an illuminated surround. This brightness‐luminance function is represented by a psychoneural visual‐contrast model having two channels, one corresponding to the brightness of the target and the other to the brightness of the surround. The principal ascending and descending pathways in each channel are represented by a submodel which is equivalent to the intensity‐perception model described by MacKay. The interaction between the channels, which accounts for the perception of contrast, takes the form of nonlinear lateral inhibition. Brightness responses calculated with the use of the pshychoneural contrast model correspond very closely to the data upon which the brightness‐luminance function is based.
Effects of small organic molecules on the cholinergic receptors of the motor endplate
Authors: Saji Y. , del Castillo J.
Published: January 2005

This paper deals with the effects on the endplate receptors of the electro‐osmotic and bath application of compounds which, although lacking pharmacological affinity, mimic the actions caused at much lower concentrations by conventional cholinergic drugs. Small cyclic molecules containing carbonyl, ether, ester, amide, and carboxyl anhydride groups were tested. Lactones, carboxyl anhydrides, cyclic amides, and ketones depolarized the endplate membrane and, in addition, most of them potentiated the depolarizing action of acetylcholine. On the contrary, cyclic ethers behaved as neuromuscular blocking agents. Dioxane, which contains two ether oxygens, caused a marked prolongation of the time course of the potentials elicited by the iontophoretic application of acetylcholine pulses. In some instances the effects of adding the compounds to the bath were different from those observed following local electro‐osmotic application.