bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induced Degradation of Glycosaminoglycans in Hurler's and Hunter's Syndromes by Plasma Infusion
Authors: Ferrante Nicola Di , Nichols Buford L. , Donnelly Patricia V. , Neri Giovanni , Hrgovcic Ruzica , Berglund Robert K. 
Published: May 2006

The effects of the administration of normal human plasma to patients affected by mucopolysaccharidoses I and II (Hurler's and Hunter's syndromes) have been evaluated. The infusion was followed by a decreased urinary excretion of relatively large molecular weight glycosaminoglycans and by an increased excretion of their products of degradation. Among the latter, products of the degradation of dermatan sulfate and heparan sulfate could be demonstrated.
The results indicate that normal human plasma may contain those “factors” that are involved in the normal degradation of dermatan sulfate and heparan sulfate, that are missing in the diseased states.
Viruses as an Aid to Cancer Therapy: Regression of Solid and Ascites Tumors in Rodents After Treatment with Bovine Enterovirus
Authors: Taylor M. W. , Cordell B. , Souhrada M. , Prather S. 
Published: May 2006

Treatment of ascites and solid tumors in mice (Sarcoma-1 and Ehrlich ascites carcinoma) with bovine enterovirus-1 resulted in regression of the tumors without any pathological effect on the animals. Death of mice with lymphatic-leukemia L4946 was delayed after such treatment. The oncolytic specificity of the virus does not appear to involve the production of interferon, but requires specific adsorption of virus to the tumor cells. The specificity of killing extends to cells in culture, since viral-transformed cells and oncogenic cells are susceptible to the virus, in contrast to cells of untransformed lines and cells of primary cultures, which are resistant.
The possibility of utilizing the specificity of nonvirulent viruses in therapeutic treatment of human cancers is considered.
Interrelationship Between Adenylate Cyclase Activity, Adenosine 3′:5′ Cyclic Monophosphate Phosphodiesterase Activity, Adenosine 3′:5′ Cyclic Monophosphate Levels, and Growth of Cells in Culture
Authors: Anderson Wayne B. , Russell Thomas R. , Carchman Richard A. , Pastan Ira 
Published: May 2006

To investigate how cell population density influences the intracellular concentration of cyclic AMP we have measured adenylate cyclase and cyclic AMP phosphodiesterase activities and cyclic AMP levels at various stages of cell density in normal rat-kidney (NRK) cells, which exhibit contact-inhibition of growth, and in normal chick-embryo fibroblasts (CEF), which do not show contact inhibition of growth under our conditions. Until NRK cells reach confluency, both activities increase with increasing cell population and cyclic AMP levels are low. As NRK cells reach confluency, cyclic AMP phosphodiesterase activity decreases somewhat whereas adenylate cyclase activity continues to rise. This increase in synthetic ability is accompanied by the increase in cyclic AMP levels which occurs in these cells at confluency. In CEF grown in 5% serum where density-dependent inhibition of growth is not observed, both adenylate cyclase and cyclic AMP phosphodiesterase activities increase proportionately with increasing cell population density. No significant alteration occurs in the ratio between these two enzyme activities and no change is observed in cyclic AMP levels.
The NaF-stimulated activity in NRK cells increases with increasing cell density until the cells reach confluency; thereafter the NaF-stimulated activity remains constant. In contrast, the NaF-stimulated activity observed in CEF does not vary appreciably between light and heavy density.
The observed changes in the enzymes of cyclic AMP metabolism accurately reflect the changes in cyclic AMP concentration as a function of cell population density. The data indicate that these two enzyme activities respond to increasing cell density to elicit a rise in intracellular cyclic AMP levels. The elevated cyclic AMP levels are thought to be involved in the regulation of cellular growth rate and the mediation of contact inhibition of growth.
Origin and Direction of Replication of Bacteriophage 186 DNA
Authors: Chattoraj Dhruba K. , Inman Ross B. 
Published: May 2006

Intracellular bacteriophage 186 DNA replicates as a single-branched circle during the first round of replication. The free end of the branch is located at a unique position with respect to phage 186 DNA base sequence, and this point should, therefore, correspond to the origin of DNA replication. The position of the growing point has been mapped at various degrees of replication, and found to move unidirectionally from left to right with respect to the denaturation map of phage 186 DNA.
A small proportion of the replicating molecules have two linear branches connected to the circle at two different branch points. These structures are consistent with two separate initiations from the same origin, again, with a unidirectional mode of replication. Branch points frequently have a single-stranded connection between the circle and the branch; significant numbers of branch points also possess an extra short single-stranded “whisker” protruding out of the branch point.
Facts and Theories on Viruses Causing Cancer and Leukemia
Authors: Gross Ludwik 
Published: May 2006

It is possible to explain the familial incidence of cancer developing in several members of the same family tree, within the same as well as in successive generations, by an assumption that tumors and leukemia are caused by oncogenic viruses transmitted in a latent form from one generation to another in many animal species, presumably also in man. The term “vertical transmission” was coined to describe this form of transmission of pathogenic agents. In most instances the oncogenic viruses are invisible and harmless to their carrier hosts. Occasionally, however, under the influence of endogenous or exogenous inducing factors, these viruses become activated and cause cancer or leukemia. According to this concept, the law of obligate communicability established for all common infectious agents applies also to oncogenic viruses: each tumor or leukemia can be traced to another similar tumor which developed in one of the preceding generations as a result of “vertical” passage of the same oncogenic virus. This concept postulates that at one time, perhaps centuries ago, these viruses entered from outside the animal hosts and that, since then, they have been transmitted from one generation to another.
The theory of vertical transmission of latent oncogenic viruses is consistent with experimental and clinical observations made during the preceding two decades. We consider this concept to be a logical and most promising approach to the problem of viral etiology of neoplastic diseases.
Mobility and distribution of a cell surface glycoprotein and its interaction with other membrane components
Authors: Schlessinger J. , Barak L. S. , Hammes G. G. , Yamada K. M. , Pastan I. , Webb W. W. , Elson E. L. 
Published: May 2006

Fluorescence photobleaching recovery and immunofluorescence methods have been used to study the lateral mobility and topographical distribution of a major cell surface glycoprotein (CSP). Both endogenous CSP and fluorescent-labeled exogenous CSP bind to the cell surface in a fibrillar pattern and are immobile on the experimental time scale. Azide, vinblastine, and cytochalasin B do not alter the immobility and cell surface distribution of the CSP molecules. Therefore, oxidative phosphorylation and the cytoskeleton do not seem to be responsible for the properties of the bound glycoprotein. The presence of immobile CSP fibrils does not, however, impede the diffusion of a lipid probe, a ganglioside analogue, or various surface antigens. Therefore, the fibrils apparently do not form a “barrier” across the lipid phase of the plasma membrane. In contrast, concanavalin A binds to CSP and is largely immobile in regions rich in CSP. The presence of immobile concanavalin A receptors in areas or on cells lacking CSP indicates that other types of immobile concanavalin A receptors also exist.
CSP does not bind to lipid bilayers composed of phosphatidylcholine or oxidized cholesterol. It does bind to dextran-coated bilayers as a diffuse distribution of mobile molecules that can patch after addition of antibodies to CSP. The latter result suggests that CSP molecules do not interact strongly with other CSP molecules under these conditions. Exogenous CSP binds to regions on the cell surface that already bear CSP. In view of the apparent weakness of CSP-CSP interactions on the lipid bilayer, it seems possible that the assembly of CSP fibrils is nucleated by cell surface components in addition to CSP.
Membrane-controlled depletion of complement activity by spin-label-specific IgM
Authors: Humphries Gillian M. K. , McConnell Harden M. 
Published: May 2006

Complement depletion mediated by high molecular weight (IgM) rabbit antibodies specifically bound to spin-label lipid haptens dispersed in model membranes is controlled by various physical attributes of those membranes other than the total number of exposed determinants that they provide. Carrier lipids used at 32° were (
i
) a “fluid” phosphatidylcholine (PC), (
ii
) a “solid” PC, and (
iii
) a cholesterol/PC mixture. The concentration of hapten in the plane of the membranes (two-dimensional concentration) was varied while the overall hapten molarity (three-dimensional concentration) was kept constant.

Both specific binding and the efficiency of depletion by IgM are markedly enhanced by systematically decreasing the average distance between haptens (∞ → 26 A). Heterogeneous distribution was found to be more favorable than a random homogeneous distribution of the same number of haptens in the same total quantity of lipids. IgM efficiency is also markedly increased by the inclusion of cholesterol in PC membranes, an effect thought to result from enhanced projection of the determinant from the surface of the membrane and hence increased accessibility to the antibody-binding site. Furthermore, the efficiency of IgM was increased by using haptens dispersed in fluid rather than in solid PC membranes.
The results are consistent with the hypothesis that IgM molecules must be bound to a critical multiple of antigenic determinants at a membrane surface in order to induce complement-mediated attack and that subtle variation of the physical state of membrane antigens can be the crucial factor in determining the outcome of this type of efferent immune response.
Expression of Ia-like antigen molecules on human granulocytes during early phases of differentiation
Authors: Winchester R. J. , Ross G. D. , Jarowski C. I. , Wang C. Y. , Halper J. , Broxmeyer H. E. 
Published: May 2006

Human B lymphocyte antigens analogous to the murine Ia determinants were found on myeloblasts and promyelocytes but not on more mature granulocytes. This was apparent by fluorescent staining with both human alloantisera and rabbit antisera to the isolated Ia-like proteins. The cells of patients with chronic myelocytic leukemia showed this difference especially clearly. Separation of the myeloblasts and promyelocytes by multistep density gradient fractionation produced a marked enrichment of the positive cells. The remaining cells from higher density fractions were more-mature neutrophils that were essentially negative. In acute myeloid leukemia, in which myeloid cells early in differentiation predominate, the vast majority of cells were strongly positive. Similar results were obtained with normal bone marrow cells. Here also, only the early forms of the myeloid series separated by gradient centrifugation had Ia antigens. Evidence was also obtained for the presence of Ia determinants on cells with the appearance of early erythroid precursors. Support for the presence of the Ia determinants on granulocyte-macrophage committed stem cells was provided by the inhibition of granulocyte colony formation in agar cultures following preincubation of normal bone marrow with antiserum and complement.
Cross absorptions with purified preparations of immature cells provided evidence for the close similarity of the antigenic determinants on both myeloblasts and B cells. A 28,000-37,000-dalton bimolecular complex obtained from myeloblast membranes contained the Ia determinants and was similar to that obtained from peripheral blood B cell membranes.
The law of perceptual stability: Well-definedness and validity
Authors: Shiman Leon G. 
Published: May 2006

Axiomatic foundations for a theory of perception have been given in a prior communication [Shiman, L. G. (1978)
Proc. Natl. Acad. Sci. USA
75, 2049-2053]. The theory is based on mathematically characterized stable images. Stable images model subjective (psychological) states of observers. We showed there is a universal procedure by which such stable images can be assigned to objects of perception (icons), employing observer-dependent perceptual judgements.

We construct an abstract model for an icon from the mathematical structure of a stable image that has been assigned to it. We identify the model with the icon. By identifying the model with the object of perception, we can analyze perception of the icon in terms of the mathematical properties of its associated stable images. Thus subjective phenomena, in this mathematical form, can be used to analyze the mechanisms of sensory processes.
Grounds for validity of the stability law are given. The procedures are demonstrably universal. A stable image, although subjectively derived from an icon, is a mathematical entity, and has therefore objective status. Stable images give a natural and potentially complete (mathematical) classification of icons, along nontraditional lines, which includes a classification and account of many well-known “visual illusions.”

Extension of this (
static
) theory to include time-dependent (
kinetic
) cases is outlined. We consider grammar for vision, semantics, and the role of stability theory in constructing a unified theory of vision and natural languages.
Cloning and characterization of a putative inhibitor of melanization from Anopheles gambiae
Authors: Shi L. , Li B. , Paskewitz S. M. 
Published: May 2006

AbstractPhenoloxidases, including tyrosinases and laccases, are enzymes involved in the synthesis of melanin, a process that can be elicited during insect immune responses, cuticle maturation, wound healing and egg chorion development. We cloned a putative inhibitor of melanization (POI) from Anopheles gambiae on the basis of homology with a functionally characterized peptide from Musca domestica (Daquinag et al., Proc Natl Acad Sci USA 1995; 92: 2964–2968). The 335 amino acid protein predicted from the A. gambiae cDNA consists of five tandemly arranged inhibitor motifs. The A. gambiae POI gene was expressed in all mosquito stages from egg to adult. POI transcript levels were high in the fat body and were measurable but comparatively reduced in the midgut. The POI transcript level increased after wounding or Sephadex bead injection. Gene knockdown did not result in faster or more extensive bead melanization but did result in more extensive melanization of wound sites following a thoracic bead injection.
Music and language side by side in the brain: a PET study of the generation of melodies and sentences
Authors: Brown Steven , Martinez Michael J. , Parsons Lawrence M. 
Published: May 2006

AbstractParallel generational tasks for music and language were compared using positron emission tomography. Amateur musicians vocally improvised melodic or linguistic phrases in response to unfamiliar, auditorily presented melodies or phrases. Core areas for generating melodic phrases appeared to be in left Brodmann area (BA) 45, right BA 44, bilateral temporal planum polare, lateral BA 6, and pre‐SMA. Core areas for generating sentences seemed to be in bilateral posterior superior and middle temporal cortex (BA 22, 21), left BA 39, bilateral superior frontal (BA 8, 9), left inferior frontal (BA 44, 45), anterior cingulate, and pre‐SMA. Direct comparisons of the two tasks revealed activations in nearly identical functional brain areas, including the primary motor cortex, supplementary motor area, Broca's area, anterior insula, primary and secondary auditory cortices, temporal pole, basal ganglia, ventral thalamus, and posterior cerebellum. Most of the differences between melodic and sentential generation were seen in lateralization tendencies, with the language task favouring the left hemisphere. However, many of the activations for each modality were bilateral, and so there was significant overlap. While clarification of this overlapping activity awaits higher‐resolution measurements and interventional assessments, plausible accounts for it include component sharing, interleaved representations, and adaptive coding. With these and related findings, we outline a comparative model of shared, parallel, and distinctive features of the neural systems supporting music and language. The model assumes that music and language show parallel combinatoric generativity for complex sound structures (phonology) but distinctly different informational content (semantics).
A novel mechanosensitive channel identified in sensory neurons
Authors: Cho Hawon , Koo Jae Yeon , Kim Sangsung , Park Sung Pyo , Yang Youngduk , Oh Uhtaek 
Published: May 2006

AbstractMechanosensitive (MS) channels are ion channels gated by different types of mechanical stimuli. MS channels in sensory neurons are thought to be molecular transducers for somatic sensations such as touch, pressure, proprioception and pain. Previously, we reported that two types of MS channels are present in sensory neurons. These channels are termed low threshold (LT) and high threshold (HT) MS channels based on their pressure threshold for activation. Here, we report another type of MS channel present in sensory neurons. The channel is activated by low pressure applied to a patch (threshold ∼20 mmHg, similar to that in the LT channel). However, because this channel has a smaller single‐channel conductance than that of the LT channel, the newly classified MS channel is now called a low threshold small conductance (LTSC) channel. Unlike the LT channel, which has outwardly rectifying currents, the current–voltage relationship of the LTSC is linear. The LTSC was permeable to monovalent cations and Ca2+, and reversibly blocked by gadolinium, a blocker of MS channels. Unlike the LT channel, the LTSC was sensitized by prostaglandin E2, an inflammatory mediator that is known to sensitize nociceptors to mechanical stimuli. LTSC channels were found mostly in small cultured sensory neurons. Thus, these results suggest that the LTSC is a distinct type of MS channel that is different from the LT and HT channels in sensory neurons, and that LTSCs might play a role in mediating somatosensations, including pain.
Lack of neurogenesis in the adult rat cerebellum after Purkinje cell degeneration and growth factor infusion
Authors: Grimaldi Piercesare , Rossi Ferdinando 
Published: May 2006

AbstractAlthough constitutive neurogenesis exclusively occurs in restricted regions of the adult mammalian brain, resident progenitors can be isolated from many different CNS sites, and neuronal neogeneration can be stimulated in vivo by injury or infusion of growth factors. To ask whether latent compensatory mechanisms, which may be exploited to promote repair processes, are present throughout the CNS, we examined the neurogenic potentialities of the adult rat cerebellum in normal conditions, following injury, and after infusion of growth factors. Degeneration of Purkinje cells was induced by intracerebroventricular administration of the toxin saporin, conjugated to anti‐p75 antibodies. In addition, epidermal growth factor and basic fibroblast growth factor, or FGF8, were infused for 2 weeks to either intact or injured animals. In all conditions, proliferating cells were identified from bromodeoxiurydine (BrdU) incorporation. In the unmanipulated cerebellum there were rare dividing cells, mainly represented by NG2‐positive presumptive oligodendrocyte precursors. Mitotic activity was strongly enhanced in cortical areas with Purkinje cell degeneration, being mostly sustained by microglia, plus minor fractions of NG2‐expressing cells, astrocytes and oligodendrocytes. In contrast, growth factor infusion had a weak effect on both intact and injured cerebella. In all experimental conditions, we never found any BrdU‐positive cells coexpressing distinctive markers for immature or differentiated cerebellar neurons. Therefore, although some progenitor cells reside in the adult cerebellum, the local environment, either intact or injured, does not provide efficient cues to direct their differentiation towards neuronal phenotypes. In addition, neurogenic potentialities cannot be induced or boosted by the application of growth factors which are effective in other CNS regions.
Clearance and prevention of prion infection in cell culture by anti‐PrP antibodies
Authors: Pankiewicz Joanna , Prelli Frances , Sy Man‐Sun , Kascsak Richard J. , Kascsak Regina B. , Spinner Daryl S. , Carp Richard I. , Meeker Harry C. , Sadowski Marcin , Wisniewski Thomas 
Published: May 2006

AbstractPrion diseases are transmissible and invariably fatal neurodegenerative disorders associated with a conformational transformation of the cellular prion protein (PrPC) into a self‐replicating and proteinase K (PK)‐resistant conformer, scrapie PrP (PrPSc). Humoral immunity may significantly prolong the incubation period and even prevent disease in murine models of prionoses. However, the mechanism(s) of action of anti‐PrP monoclonal antibodies (Mabs) remain(s) obscure. The murine neuroblastoma N2a cell line, infected with the 22L mouse‐adapted scrapie strain, was used to screen a large library of Mabs with similar binding affinities to PrP, to identify those antibodies which could clear established infection and/or prevent infection de novo. Three Mabs were found capable of complete and persistent clearing of already‐infected N2a cells of PrPSc. These antibodies were 6D11 (generated to PK‐resistant PrPSc and detecting PrP residues 93–109), and 7H6 and 7A12, which were raised against recombinant PrP and react with neighbouring epitopes of PrP residues 130–140 and 143–155, respectively. Mabs were found to interact with PrPSc formation both on the cell surface and after internalization in the cytosol. Treatment with Mabs was not associated with toxicity nor did it result in decreased expression of PrPC. Both preincubation of N2a cells with Mabs prior to exposure to 22L inoculum and preincubation of the inoculum with Mabs prior to infecting N2a cells resulted in a significant reduction in PrPSc levels. Information provided in these studies is important for the rational design of humoral immune therapy for prion infection in animals and eventually in humans.