bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of a neuroregulated phosphoprotein in skeletal muscle as the regulatory subunit of cyclic AMP‐dependent protein kinase II
Authors: Squinto S. P. , McLane J. A. , Held I. R. 
Published: January 2005

AbstractWhen soluble proteins in cytosolic fractions of rat soleus muscles are 32P‐phosphorylated in vitro by an ATP:protein phosphotransferase reaction, the major substrate is a 56‐kilodalton (56K) protein. As we have also reported previously, the onset and development of increased 32P‐phosphorylation of this 56K protein, which are observed after the soleus is denervated, temporally correlate with the denervation period and length of the distal nerve stump [Held et al, 1983]. Conclusive evidence which identifies this neuroregulated muscle protein as the regulatory subunit of cyclic AMP‐dependent protein kinase type II (R‐II) is presented in this paper. The 56K soleus protein and purified bovine heart R‐II were 32P‐phosphorylated and subjected to limited proteolysis with bovine pancreas trypsin. After resolution of the generated 32P‐phosphopeptides by SDS slab PAGE and visualization by autoradiography, no tryptic products were observed from the 56K soleus protein which were not also produced by proteolysis of the purified R‐II. These tryptic phosphopeptides included 39, 16.5, and 12K fragments which retained the autophosphorylation site of R‐II. After denervation, the 32P‐phosphorylation of the 56K soleus protein and of the 39K tryptic peptide product were comparably increased. The identification of the neuroregulated 56K soleus protein as R‐II was also confirmed by Western blotting with a specific anti‐R‐II sera. Taken together, our results demonstrate that the previously observed neuroregulation of the 32P‐phosphorylation of the 56K soleus protein is identifiable with some alteration which affects the intramolecular 32P‐autophosphorylation of R‐II.
Amino acid incorporation during morphine intoxication. II: Electrophoretic separation of extracellular proteins from cerebral hemisphere slices and astroglia‐enriched primary cultures
Authors: Hansson E. , Rönnbäck L. 
Published: January 2005

AbstractRadioactively labeled proteins were identified in a broad molecular weight range in the incubation medium of rat cerebral hemisphere slice preparations or primary cultures after incubation with radioactive valine. Morphine chloride caused an increase in labeled media proteins with MW ˜40,000 and 65,000 in both preparations, whereas a fraction with MW, ˜80,000 decreased in amount. In the culture preparation a MW ˜15,000 fraction also decreased after morphine treatment. The effects on the MW 40,000 and 65,000 fractions by morphine could not be blocked by naloxone hydrochloride, an opiate antagonist. Labeled media proteins from primary cultures obtained from various brain regions showed many similarties. After 10−5 or 10−6 M morphine, protein fractions with MW ˜15,000, 25,000, 40,000, 65,000–70,000, 80,000, and 100,000 changed with increases or decreases in the various morphine concentrations. The 3H‐labeling of the MW ˜40,000 fraction increased in all cultures, where it decreased.In conclusion, proteins synthesized within cells in brain slices or in astrogliaenriched cultures are released or secreted into the incubation media. Some protein fractions are affected in different directions by morphine. The effects were not correlated with the presence of classical opiate receptors on the cells. This was so even though more changes in media proteins occurred in astroglial cultures from opiate receptor‐rich brain regions than in similar cultures from opiate receptor‐poor regions. The possible significance of proteins synthesized in astroglial cells and released extracellulary in opiate action is discussed.
Effect of morphine‐induced cortical excitation on spinal sensory transmission
Authors: Hernandez A. , Soto‐Moyano R. 
Published: January 2005

AbstractBioelectrical responses evoked in the ventrolateral funiculus (VLF) of the spinal cord by electrical stimulation of the contralateral hind limb were studied following topical application of 1% morphine solution to the somatosensory SI area of the rat cerebral cortex. After morphine, a typical pattern was observed in the electrocorticogram, characterized by the appearance of rhythmic spiking activity. Time‐related with each cortical spike, a significant reduction in the amplitude of VLF responses was observed. It is concluded that cortical excitation induced by morphine generates descending influences having the ability to inhibit spinal sensory transmission.
Abnormal visual cortex development in the kitten associated with maternal dietary taurine deprivation
Authors: Palackal T. , Moretz R. , Wisniewski H. , Sturman J. A. 
Published: January 2005

AbstractWe have examined the visual cortex of newborn and 8‐week‐old kittens born to mothers consuming a taurine‐supplemented or taurine‐free diet using the rapid Golgi technique. Kittens from taurine‐supplemented mothers exhibited normal development of the visual cortex. Kittens from taurine‐depleted mothers showed striking differences. In newborn kittens, neuroblasts are aggregated both at the ventricular and pial zones, having failed to migrate and differentiate normally. Eight weeks after birth, only few pyramidal and nonpyramidal neurons are found. Those present have heavily spined dendritic processes indicative of poor arborization. Protoplasmic astrocytes are represented by undifferentiated cellular masses. The taurine concentration in the cortex of such kittens is four‐ to fivefold smaller than in kittens from taurine‐supplemented mothers.These results suggest that normal concentrations of taurine in visual cortex, as well as cerebellum, are required for normal ontogeny of neurons. Once such deficits are established in the prenatal and immediate postnatal period, they result in permanent abnormalities. These findings have clear implications for vegetarian women who intend to have children, since virtually no taurine is present in plants and vegetables.
Cellular effects of a brain extract factor or factors inhibiting neuroblastoma cell growth in vitro
Authors: Schengrund C.‐L. , Repman M. A. 
Published: January 2005

AbstractThe mechanism of inhibition of neuroblastoma cell proliferation in vitro by extract prepared from the brains of newborn mice was partially elucidated. Flow cytometric analysis of propidium iodide‐stained cells showed that a significant increase occurred in the pre‐G0/G1 cell population after exposure to the extract for 24 hr. Fluorescence microscopy indicated that the pre‐G0/G1 cells had small “micronuclei” in association with their nucleus, whereas post‐G2/M cells had enlarged propidium iodide‐staining nuclei. 3H‐thymidine incorporation was unchanged from that of control cells, in cells exposed to the extract for either 6 or 24 hr. No effect was seen on choline acetyl transferase activity or on morphology. These results suggest that the inhibitor blocks neuroblastoma cell proliferation either by inducing an uneven distribution of DNA at the time of cell division or by altering its packaging within the nucleus.
Rates of amino acid incorporation into particulate proteins in vivo and in slices of young and adult brain
Authors: Shahbazian F. M. , Jacobs M. , Lajtha A. 
Published: January 2005

AbstractIncorporation of a flooding dose of valine into brain proteins was measured in vivo and in brain slices, according to subcellular fraction and to solubility. In particulate fractions in vivo in the immature brain, soluble cytosol proteins had the highest synthesis rates (2.0% per hr), followed by microsomes (1.7%), mitochondria, nuclei (1.4%), and synaptosomes (0.85%). In adult, the rates were about half of those of immature animals except for microsomes, which were the same. In young, rates of incorporation into particles in brain slices were about 80% of in vivo rates, and adult rates were 10–20% of the in vivo rates.When brain proteins were fractionated into four groups‐isotonic soluble, hypotonic soluble, Triton X‐100 soluble, and the remainder solubilized in 0.2% SDS–in both young and adult brain in vivo, the isotonic fraction had the highest rate of protein synthesis, followed by the Triton‐soluble fraction, the SDS‐soluble fraction, and the hypotonic fraction. Also, with this method of separation in vitro rates for immature brain were 10–20% lower than in vivo rates, while in vitro adult rates were 80–90% lower.The results indicate that the most proteins are synthesized at a higher rate in the immature brain, and that the difference between in vivo and brain slice protein synthesis is not as great in the immature as in the mature brain in all the fractions examined.
Molecular adaptations in catecholamine biosynthesis induced by cold stress and sympathectomy
Authors: Stachowiak M.K. , Fluharty S.J. , Stricker E.M. , Zigmond M.J. , Kaplan B.B. 
Published: January 2005

AbstractChronic cold stress and chemical sympathectomy are known to increase the synthesis and release of catecholamines in the adrenal medulla. Chromaffin cells adapt to altered functional requirements by increasing the synthesis of tyrosine hydroxylase (TH), the rate‐limiting enzyme in catecholamine biosynthesis. In this study, we investigated the molecular genetic mechanisms underlying these changes in enzyme activity. Estimates of TH mRNA levels were obtained by RNA dotblot analysis with a cloned TH cDNA hybridization probe. Exposure to cold produced a 4.3‐fold increase in the relative abundance of adrenomedullary TH mRNA. Increases in TH mRNA levels (90%) also were observed in the brainstem of cold‐stressed animals. The relative amount of TH synthesized in vitro in a rabbit reticulocyte cell‐free system, programmed with adrenal poly (A) +RNA, increased 4.3 times in cold‐stressed rats. Alteration in TH mRNA abundance appears to be specific, as we observed no significant difference in the levels of total RNA or poly(A) +RNA in this tissue. In addition, the relative abundance of adrenomedullary TH mRNA increased by 60% 4 days after systemic administration of the neurotoxin 6‐hydroxydopamine. This increase was transient and disappeared 2 weeks after the lesion. Changes in TH mRNA levels after cold stress or sympathectomy were eliminated by denervation of the adrenal gland. These results indicate that alterations in the relative abundance of TH mRNA mediate changes in TH activity induced by chronic stress or sympathectomy, and that these changes require an intact sympathetic input.
Use of synthetic oligodeoxynucleotide probes for the isolation of a human cholinesterase cDNA clone
Authors: Prody C. , Zevin‐Sonkin D. , Gnatt A. , Koch R. , Zisling R. , Goldberg O. , Soreq H. 
Published: January 2005

AbstractCholinesterases are serine esterases that rapidly hydrolyze the neurotransmitter acetylcholine. In humans, cholinesterases exhibit extensive polymorphism in terms of their substrate specificity, sensitivity to selective inhibitors, hydrophobicity, and cellular as well as subcellular localization. It is not yet known whether the various cholinesterase forms originate from different genes or are products of posttranscriptional and posttranslational processing. The extent to which these enzyme forms are homologous in their amino acid sequence is also not known. However, a consensus organophosphate‐binding hexapeptide sequence Phe‐Gly‐Glu‐Ser‐Ala‐Gly was found both in “true” acetylcholinesterase from the electric organ of Torpedo [McPhee‐Quigley et al: J Biol Chem 260:12185–12189, 1985] and in “pseudocholinesterase” (butyrylcholinesterase) from human serum [Lockridge: “Cholinesterases—Fundamental and Applied Aspects.” New York: de Gruyter, pp 5‐12, 1984], suggesting that this region in the protein is conserved in all cholinesterases. Based on this common sequence, we prepared synthetic oligodeoxynucleotides and used them as labeled probes to screen a cDNA library from fetal human brain mRNA, cloned in lambda gt10 phages. A cDNA clone of 770 nucleotides in length was isolated. It contains an open reading frame terminating with the sequence Ser‐Val‐Thr‐Leu‐Phe‐Gly‐Glu‐Ser‐Ala‐Gly‐Ala‐Ala, which includes the consensus hexapeptide used for designing the DNA probe. Furthermore, the sequence of this 12‐amino acid peptide is identical to the sequence reported for the organophosphate binding site of human serum pseudocholinesterase [Lockridge: “Cholinesterases—Fundamental and Applied Aspects.” New York: de Gruyter, pp 5–12, 1984]. These findings confirm that the isolated clone is indeed part of a human cholinesterase cDNA.
Neuron‐specific enolase: Complete structure of rat mRNA, multiple transcriptional start sites, and evidence suggesting post‐transcriptional control
Authors: Forss‐Petter S. , Danielson P. , Sutcliffe J.G. 
Published: January 2005

AbstractThe protein encoded by a randomly selected rat brain cDNA clone was identified as neuron‐specific enolase (NSE; 4.2.1.11; gamma subunit), based on homology to yeast enolase sequences and the presence of the corresponding 2.5–kb mRNA in rat brain but not in liver, kidney, or muscle tissue. The 2,222‐nucleotide NSE and mRNA sequence presented identifies a 68‐nucleotide 5′ noncoding region, a 1,302‐nucleotide open reading frame (corresponding to a primary translation product of 434 amino acids), and 852 noncoding ' bases. Evolutionary implications based on sequence comparisons to yeast enolase and non‐neuronal enolase are discussed. Primer extension analysis indicated the presence of several alternative initiation sites for transcription within 60 nucleotides on the NSE gene. The developmental onset of NSE mRNA expression correlates with the appearance of NSE protein; however, the mRNA reaches adult levels by postnatal week 3, whereas the protein continues to accumulate over the next few months, suggesting regulatory mechanisms in addition to transcriptional control.
Brain enzyme adaptation to mild normobaric intermittent hypoxia
Authors: Marzatico F. , Curti D. , Dagani F. , Tagliti M. , Benzi G. 
Published: January 2005

AbstractThe adaptation of repeated periods of intermittent normobaric hypoxia (oxygen:nitrogen = 10:90, 12 hr daily for 5 days) of some specific enzymatic activities related to energy metabolism has been observed in different rat brain areas (cerebral cortex, hippocampus, corpus striatum, hypothalamus, cerebellum, and medulla oblongata).The evaluation of the maximum rate (Vmax) of the enzymes was carried out on: (1) the homogenate “in toto,” (2) the nonsynaptic mitochondrial fraction, and (3) the crude synaptosomal fraction. The adaptation to inermittent normobaric hypoxic exposure was characterized by significant modifications of some enzyme activities in the homogenate “in toto” (decrease of hexokinase activity in cerebellum), in the nonsynaptic mitochondrial fraction (increase of succinate dehydrogenase activity in corpus striatum and decrease of cytochrome oxidase activity in cererbral cortex), and, particularly, in the synaptosomal fraction (decrease of cytochrome oxidase activity in cerebral cortex, hippocampus, corpus striatum, and cerebellum, and decrease of malate dehydrogenase and lactate dehydrogenase activity in cererbellum).The adaptation to normobaric intermittent hypoxia differs according to the brain area, subcellular fraction, and enzyme activity tested.
Chronic neurologic dysfunction and demyelination induced in lewis rats by repeated injections of encephalitogenic T‐lymphocyte lines
Authors: Vandenbark A.A. , Nilaver G. , Konat G. , Teal P. , Offner H. 
Published: January 2005

AbstractExperimental autoimmune encephalomyelitis (EAE) in the Lewis rat is characteristically a monophasic paralytic disorder. Recovered rats are thereafter immune to EAE induced by injection of guinea pig basic protein (GP‐BP) in complete Freund's adjuvant (CFA), but they are still susceptible to EAE induced by an encephalitogenic T‐lymphocyte line (BP‐1). Induction of active EAE or injection of a sublethal dose of activated BP‐1 cells resulted in a monophasic episode of EAE, followed by recovery of normal neurologic function. Repeated challenges with activated BP‐1 cells, however, induced unremitting neurologic signs marked by loss of tail tonicity and incontinence, which persisted for more than 6 months. Histologically, the spinal cord of affected rats revealed attenuation of MBP staining (demyelination) and moderate‐to‐extensive gliosis associated with increased size of intervening spaces. Inflammatory cell lesions, however, were notably absent. Biophysical analysis of isolated spinal cord myelin from affected rats demonstrated a distorted distribution in subfraction densities and the appearance of extra‐myelin proteins in the light myelin subfraction. Immunologically, chronically affected animals were unresponsive to the encephalitogenic determinant on GP‐BP, although other BP determinants elicited strong delayed type hypersensitivity (DTH) reactions in rats immunized initially with GP‐BP in CFA. These data show that ongoing neurologic dysfunction can be induced in the Lewis rat by a GP‐BP specific T‐lymphocyte line; they suggest that unremitting clinical signs can persist in the absence both of inflammatory lesions in the CNS and of pronounced immunologic responsiveness to the encephalitogenic determinant of GP‐BP.
Uptake of GABA and nipecotic acid in astrocytes and neurons in primary cultures: Changes in the sodium coupling ratio during differentiation
Authors: Larsson O.M. , Hertz L. , Schousboe A. 
Published: January 2005

AbstractThe coupling ratio betwen sodium and GABA or the GABA analog, (RS)‐nipecotic acid, in neuronal and glial uptake of GABA or nipecotic acid was investigated as a function of the morphological differentiation of these cell types in primary cultures. Both in neurons and astrocytes a high‐affinity uptake of GABA and nipecotic acid was observed ragardless of the degree of differentiation. The values of Km were essentially identical in undifferentiated and differentiated cells. On the other hand, Vmax was significantly increased both in 10‐day‐old neurons compared to 1‐ and 3‐day‐old neurons and in astrocytes treated with dBcAMP compared to untreated cells, i.e., Vmax increased as a function of differentiation in both cell types. In neurons as well as in astrocytes the morphological differentation resulted in an alteration in the coupling ratio between sodium and GABA. From calculated Hill coefficients it could be deduced that the coupling ratio between sodium and GABA was changed from 1 to 2 during differentiation. Similar results were obtained for (RS)‐nipecotic acid.
Identification of a glycine‐like fragment on the strychnine molecule
Authors: Aprison M. H. , Lipkowitz K. B. , Simon J. R. 
Published: January 2005

AbstractStrychnine, a complex molecule, antagonizes in some unknown manner the action of glycine, an important inhibitory neurotransmitter in the spinal cord and brainstem of many vertebrates. To help understand the mechanism of this antagonism, we have employed modern computational methods to assess the similarities between these seemingly different molecules. An exhaustive comparison of topological and electronic features of both molecules was made. We have successfully located a glycine‐like fragment in the strychnine molecule that, when compared to glycine, exhibits both topological and electronic charge congruence. The successful location of this glycine‐like fragment allows us to speculate how the large strychnine molecule assumes its role as an antagonist against the inhibitory action of glycine, the simplest amino acid.
Interleukin‐1‐like activity in rat brain: Sources, targets, and effects of injury
Authors: Nieto‐Sampedro M. , Berman M. A. 
Published: January 2005

AbstractExtracts of injured rat brain contained molecules that shared biological and physicochemical properties with interleukin‐1 (IL‐1). Brain IL‐1‐like activity increased following brain injury in parallel with the increase in astrocyte and fibroblast mitogenic activity. After 3 days postlesion, it reached about 20 times the basal (noninjured) level. Monoclonal antibodies to human IL‐1 inhibited this brain IL‐1‐like activity.One of the cellular sources of brain IL‐1‐like activity seems to be astroglial cells. Primary cultures of purified rat brain astrocytes secreted into the culture medium more IL‐1 activity than comparable numbers of peripheral blood monocytes. Brain IL‐1, as well as authentic monocyte IL‐1, appear to act on brain glial cells, promoting thymidine incorporation into purified astrocytes in culture.
Investigations on myelinogenesis in vitro: Developmental expression of myelin basic protein mRNA and its regulation by thyroid hormone in primary cerebral cell cultures from embryonic mice
Authors: Shanker G. , Campagnoni A. T. , Pieringer R. A. 
Published: January 2005

AbstractThe concentration of myelin basic protein (MBP) mRNA in primary cultures of cells dissociated from embryonic mouse cerebra and grown in the presence of varying amounts of thyroid hormone was measured using a 32P‐labeled cDNA probe and a dot‐blot procedure. The cDNA probe contained 1.85 kilobases of the gene for MBP. The concentration of mRNA specific for MBP in control cells grown on a medium containing normal (euthyroid) calf serum increased with increasing age of culture. The greatest increase occurred between 15 and 35 days in culture (5.25‐fold increase); whereas between 35 and 50 days in culture, the rate of accumulation slowed to yield a net increase of MBP mRNA of only 10%. The quantity of MBP mRNA was drastically diminished at all ages studied when the cells were grown from the sixth day onward on a medium containing hypothyroid calf serum. Although the amount of MBP mRNA in hypothyroidtreated cells did increase, the change in concentration was less (3.43‐fold), and it peaked earlier (at 30 days). Unlike the euthyroid cells, after 30 days the MBP mRNA actually fell in the hypothyroid‐treated cells. If hypothyroid media were supplemented with triiodothyronine (T3) on the eighth day in culture, the quantity of MBP mRNA in the cells was restored almost completely to the levels found in the control euthyroid cells at all ages. Therefore, the regulation of the synthesis of MBP by thyroid hormone is at least in part a pretranslational event; that is, thyroid hormone adjusts the concentration of the mRNA specific for MBP.
Transplant‐derived astrocytes migrate into host lumbar and cervical spinal cord after implantation of El4 fetal cerebral cortex into adult thoracic spinal cord
Authors: Goldberg W. J. , Bernstein J. J. 
Published: January 2005

AbstractFourteen‐day gestation fetal cerebral cortex homografts were transplanted into the thoracic (T6) spinal cord between the left dorsal column and dorsal horn of adult host rats. The transplants were soaked in 2.0 pg/ml of the lectin Phaseolus vulgaris leucoagglutinin (PHAL) prior to implantation. Transplanted host spinal cords were utilized at 7, 14, and 24 d and at 1 and 2 months postimplantation. Paraffin‐sectioned spinal cords were double labeled for PHAL and glial fibrillary acidic protein (GFAP) by using FITC‐ and RITC‐conjugated secondary antisera, respectively. Montages of FITC‐ and RITC‐positive cells were analyzed for cells containing both fluorescences. Double‐labeled cells (PHAL‐GFAP) were transplant‐derived astrocytes. Transplant‐derived astrocytes were observed to initiate migration in the white matter columns of the host at approximately 14 d after transplantation. Double‐labeled astrocytes were observed in cervical and lumbar spinal cord of the host (ca. 3.5 cm away from the center of the transplant) at 2 months postoperative. These astrocytes migrated at approximately 0.76 mm a day (after a 14‐d delay). At 2 months, transplant‐derived astrocytes composed as much as 50% of the astrocytes in the white matter of the host 2.0 mm from the transplant. The migrated astrocytes were hypertrophied and appeared reactive. Astrocytes in spinal gray matter only migrate about 1.0 mm from the graft‐host interface. Transplant‐derived astrocytes can migrate the entire length of the spinal cord white matter.