bluuebunny/crossref_metadata_2025_split huggingface dataset:
UPTAKE OF GLUCOSE ANALOGUES BY RAT BRAIN CORTEX SLICES: Na+‐INDEPENDENT MEMBRANE TRANSPORT
Authors: Lund‐Andersen H. , Kjeldsen Christel S. , Hertz L. , Brondsted H. E. 
Published: December 2006

Abstract— The glucose analogues 3‐O‐methyl‐D‐glucose and α‐methyl‐D‐glucoside were not metabolized in brain tissue.The uptake of these two sugars into the intracellular compartment of brain cortex slices was investigated using media with normal and low Na+ concentration (replacement of all NaCl with choline Cl). The cellular transport was not Na+‐dependent. The transport mechanism clearly distinguished between the two sugars in both normal and low Na+ media.
METABOLIC RELATIONSHIPS BETWEEN MYELIN SUBFRACTIONS: ENTRY OF PROTEINS 1
Authors: Benjamins Joyce A. , Gray Marjory , Morell P. 
Published: December 2006

Abstract— Partially purified myelin from brains of 17‐day‐old rats was separated into 4 subfractions on a discontinuous sucrose gradient by virtue of heterogeneity in density and particle size. The protein composition of each subfraction was determined by densitometry following separation of proteins on polyacrylamide gels in buffers containing sodium dodecyl sulphate. The major proteins studied included two basic proteins, proteolipid protein, the major high molecular weight protein (W) and a group of high molecular weight proteins.The percentage of high molecular weight proteins decreased sequentially from fraction D to A, that of the W protein remained constant, while relative amounts of the two basic proteins increased. Proteolipid protein concentration also increased as a percentage of the total protein from fraction D to B, but the uppermost fraction. A, had a markedly lower amount than fraction B. At 1 h after intracranial injection of [3H]leucine, the specific radioactivity of the basic and proteolipid proteins decreased from fraction D to B, with proteolipid protein in fraction A again anomalous (specific radioactivity higher than expected). These results are consistent with (but do not prove) a precursor‐product relationship for individual proteins from denser to lighter subfractions, with the exception of myelin subfraction A.Experiments involving time staggered injections of a [14C] and later a [3H] labelled amino acid gave data which demonstrated that the W and basic proteins were added simultaneously (or with delays of much less than 20 min) to all of the subfractions, while proteolipid protein was added sequentially, from lower to upper fractions on the gradient. This double isotope technique also confirmed our previous observations that proteolipid protein shows a lag in entry into myelin compared to basic protein.
DEVELOPMENTAL FEATURES OF CEREBELLAR HYPOPLASIA AND BRAIN BILIRUBIN LEVELS IN A MUTANT (GUNN) RAT WITH HEREDITARY HYPERBILIRUBINAEMIA 1
Authors: Sawasaki Y. , Yamada N. , Nakajima H. 
Published: December 2006

Abstract— The marked cerebellar hypoplasia found in the homozygous (jj) Gunn rat with hereditary unconjugated hyperbilirubinaemia may provide an explanation of bilirubin neurotoxicity in vivo. In the jj Gunn rat. Purkinje cells were nearly selectively affected in the cerebellar cortex, and the cerebellar weight showed no increase after 10 days of age. The development‐dependency of the cerebellar lesion was supported by the observation that the cerebellar lobuli which developed earlier were less affected. Brain bilirubin in the developing jj Gunn rat was determined by a spectrophotometric method, and was found to be extremely low (1–3 μg). The level of brain bilirubin decreased after birth, and showed little correlation with the level of bilirubin free of albumin which correlated clearly with total serum bilirubin level even in the neonate. These findings suggest that there is an affinity of brain tissue for bilirubin associated with the blood‐brain barrier to bilirubin. No significant difference was found between the levels of bilirubin in the cerebellum and those of other brain regions in jj Gunn rat.These results seem to imply that the development‐dependency of cerebellar hypoplasia in the jj rat may be due to the characteristic nature of rat cerebellar development, i.e. the postnatal neurogenesis. and not to changes in brain bilirubin levels. In the jj Gunn rat. cerebellar cell proliferation appears to be in some way affected by bilirubin during cerebellar development.
INFLUENCE OF LIPIDS ON THE ACTIVITY OF CEREBROSIDE‐SULPHOTRANSFERASE IN MOUSE BRAIN: A COMPARATIVE STUDY OF JIMPY AND NORMAL MOUSE BRAINS 1
Authors: Siegrist H. P. , Burkart T. , Steck A. J. , Wiesmann U. , Herschkowitz N. N. 
Published: December 2006

Abstract— The effect of lipids other than the substrate cerebroside on the activity of cerebroside‐sulphotransferase (CST) in Jimpy and normal mouse brain was investigated.The enzyme activity of an acetone‐treated microsomal preparation can be stimulated in the presence of the extracted lipids either with or without addition of exogenous cerebroside as a substrate.The CST activity in the Jimpy mutant compared to that in normal animals differs from 18% in homogenate to approx 80% in solubilized or acetone‐extracted microsomes.An addition of total lipid from normal mouse brain to microsomal preparations from which lipid has been removed by acetone results in a stimulation of Jimpy CST activity up to a value of 80% of normal mouse brain microsomes.Both Jimpy and normal mouse brain CST can be also stimulated by the addition of single lipid components such as cholesterol and lecithin by 50% in normal and 100% in Jimpy brain microsomes.These findings lead to the hypothesis that there is a lipid requirement for CST activity other than the substrate cerebroside.
NEUROCHEMISTRY OF THE MUCOPOLYSACCHARIDOSES: BRAIN LIPIDS AND LYSOSOMAL ENZYMES IN PATIENTS WITH FOUR TYPES OF MUCOPOLYSACCHARIDOSIS AND IN NORMAL CONTROLS
Authors: Constantopoulos George , Dekaban Anatole S. 
Published: December 2006

Abstract— Lipids and certain lysosomal enzymes were measured in the cerebral gray and white matter and in the liver of unaffected controls and six patients with mucopolysaccharidosis (MPS). Three of the patients had MPS Type I (Hurler), one Type II (Hunter), one Type IIIA (Sanfilippo A) and one Type V (Scheie). The glycosaminoglycans (GAG) of those tissues have been fully characterized previously (Constantopouloset al., 1976).Results of the present study: the normally minor brain monosialogangliosides GM2 and GM3 were markedly increased in the gray and to a lesser extent in the white matter of all the patients, except the patient with MPS Type V. On an average GM2 comprised 8.2 and 6.3, and GM3 11.8 and 6.0% of the total ganglioside neuraminic acid of the gray and white matter respectively in all patients with MPS I, II, and IIIA (normal subjects had less than 1).Ceramide dihexoside was also increased in the gray matter of the patients with MPS I, MPS II and MPS IIIA.The sphingolipid abnormalities were found only in tissues containing excessive amounts of partially degraded dermatan and heparan sulfates or heparan sulfate alone.Of the six acid hydrolases assayed, the activity of /f‐glucosaminidase was increased in both brain and liver, while that of α‐galactosidase and β‐galactosidase was diminished, particularly in the liver.These results suggest that the partially degraded heparan sulfate (and perhaps the dermatan sulfate) which accumulate in the tissues of the patients with MPS may inhibit catabolic enzymes of various sphingolipids. In turn, accumulation of sphingolipids could be responsible at least for some of the brain damage and the mental retardation in MPS I, II and IIIA.
NUCLEAR‐CYTOSOL INTERACTIONS THAT FACILITATE RELEASE OF RNA FROM MOUSE BRAIN NUCLEI
Authors: Weck P. K. , Johnson T. C. 
Published: December 2006

Abstract— Mouse brain nuclei were incubated in vitro under conditions that primarily lead to the synthesis of radioactive polydisperse and messengerlike nuclear RNA. After incubation the effects of Mg2 concentrations, nucleoside triphosphate levels and brain cytosol were examined with regard to their ability to influence the release of RNA from brain nuclei. The presence of 8 mM‐MgCl2 and a total of 0.3 mM‐nuclcoside triphosphates during the labelling procedure allowed only a minimal amount of RNA to be released. However, when the MgCl2 was decreased to 2 mM and the nucleoside triphosphates were increased to 1 mM, a stimulation of RNA release was observed. The addition of unfractionated brain cytosol under these conditions resulted in an inhibition of RNA release.G‐100 Sephadex filtration removed detectable RNase activity from the cytosol preparations and allowed the identification of fractions that were able to facilitate nuclear RNA release by 3‐fold. The fractions that stimulated release did not have detectable levels of RNase, protease or DNA‐dependenl RNA polymerase. Under conditions that provided maximum nuclear RNA release by both labelled mouse brain and neuroblastoma nuclei, no release of DNA could be measured. The cytosol fractions that facilitated RNA release did not have a high affinity for nuclear RNA or an ability to stimulate nuclear RNA synthesis. However, other components in the cytosol were shown to stimulate RNA metabolism in isolated mouse brain nuclei and to have a relatively high binding affinity to nuclear RNA. Further purification of the RNA release components in the brain cytosol by DEAF. Sephadex chromatography allowed an increase in specific activity of at least 40‐fold. The thermal lability, effective filtration size, and solubility in phenol suggested that the cytosol factors that facilitiated nuclear RNA release were associated with cellular proteins.
CAPABILITY OF TUBULIN AND MICROTUBULES TO INCORPORATE AND TO RELEASE TYROSINE AND PHENYLALANINE AND THE EFFECT OF THE INCORPORATION OF THESE AMINO ACIDS ON TUBULIN ASSEMBLY
Authors: Arce C. A. , Hallak Marta E. , Rodriguez J. A. , Barra H. S. , Caputio R. 
Published: December 2006

Abstract— Incorporation of [14C]tyrosine into the C‐terminal position of α‐tubulin of rat brain cytosol was 10‐fold higher for non‐assembled than for assembled tubulin. The incorporation into tubulin from disassembled microtubules was higher than into non‐assembled tubulin; therefore, the low incorporation into microtubules was not due to a lower acceptor capacity of their tubulin constituent.[14C]Tyrosine was released from assembled and non‐assembled [14C]tyrosinated tubulin by the action of an endogenous carboxypeptidase. Release from non‐assembled tubulin was shown by incubating a tubulinyl‐[14C]tyrosine preparation in the presence of CaCl2 at a concentration that abolished microtubule formation. Release from microtubules was inferred from the observation that the percentages of [14C]tyrosine released and the decrease of the specific radioactivity of the recovered microtubules were practically identical and did not change after a 10‐fold dilution of the incubated microtubules.[3H]Phenylalanine was released from a preparation of tubulinyl‐[3H]phenylalanine also by an enzymatic activity.The capacity of a tubulin preparation to incorporate tyrosine was increased 43% by pre‐treatment with endogenous carboxypeptidase.Tubulin tyrosinated in vitro was assembled to the same extent as native tubulin. After a mixture of tubulinyl‐[14C]tyrosine and tubulinyl‐[3H]phenylalanine was partially assembled, the ratio of 14C/3H found in the microtubules was the same as in the non‐assembled tubulin fraction.
RNA METABOLISM IN THE GOLDFISH RETINA DURING OPTIC NERVE REGENERATION1, 2
Authors: Burrell Harry R. , Dokas Linda A. , Agranoff Bernard W. 
Published: December 2006

Abstract— In goldfish, regeneration of the optic nerve following axotomy is accompanied by changes in retinal RNA metabolism. Approximately 4 days after unilateral optic nerve crush, there is an increased uptake of 3H‐labeled precursors of RNA into cells of the retina as well as an increase in labeling of total retinal RNA following incubation for 3–4 h in vitro. Subfractionation indicates that the resultant labeled free ribosomai RNA has a much higher specific activity than that from membrane‐bound ribosomes in post‐crush, as compared to normal retinas. Total retinal RNA content also increases, reaching a peak value about 8 days after axotomy, coincident with the time of observed maximum labeling of ribosomal RNA. No change in the total protein or DNA content of the retina is detected during this period as a result of the optic nerve crush.Saturating amounts of uridine or adenosine in the medium eliminate the general effects of enhanced uptake of the precursors on RNA labeling. Elevated labeling of poly(A)‐containing RNA in retinal cytoplasm is nevertheless detected 10–14 days after optic nerve crush with no change in the labeling of the polyadenylate segment. A decrease in the labeling of poly(A)‐containing nuclear RNA, from a significantly greater amount than that of normal retinas to a significantly lower one, occurs during the period of observed increased labeling of cytoplasmic poly(A)‐containing RNA. The results indicate that in addition to changes in RNA precursor metabolism, optic nerve regeneration is characterized by alterations in the labeling of free and membrane‐bound retinal ribosomes as well as in the post‐transcriptional processing of messenger RNA.
Composition and Subcellular Distribution of Glycoproteins and Glycosaminoglycans Undergoing Axonal Transport in Garfish Olfactory Nerves
Authors: Elam John S. 
Published: December 2006

Abstract: The study examined the subcellular distribution of [3H]glucos‐amine‐labeled glycoconjugates undergoing axonal transport in 100,000 ×g soluble and two membranous subfractions of the garfish olfactory nerve. Analysis was made of intact glycoconjugates and of glycopeptides and glycosaminoglycans derived from these molecules by limit protease digestion. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis revealed labeling of a variety of high‐molecular‐weight molecules with a lower molecular weight distribution in the soluble fraction than in the membranous fractions. Following protease digestion, nearly two‐thirds of transported radioactivity in glycopeptides was recovered in the plasma membrane‐enriched subfraction, with the remainder equally divided between soluble and higher density membrane fraction. Comparison of the distribution of glycopeptide radioactivity and chemically assayed hexosamine revealed transport labeling of a large variety of different‐sized neutral and acidic glycopeptides in all subfractions. Transport labeling of most glycoprotein carbohydrate chains was in proportion of their hexosamine content.Transported glycosaminogiycan label was most heavily concentrated in the plasma membrane fraction, whereas hexosamine was most concentrated in the higher density membrane fraction. The labeling pattern suggested both transported and nontransported pools of these molecules. The specific glycosaminoglycans chondroitin sulfate and heparan sulfate were recovered in all subfractions, whereas hyaluronic acid was confined to the soluble fraction.
Function of cardiac M3receptors
Authors: Wang H. , Lu Y. , Wang Z. 
Published: December 2006

Summary1 Since the initial identification of the M3subtype of muscarinic acetylcholine receptors (M3‐mAChR) in the heart, there have been increasing interest and advances in studies on the pathophysiological roles of M3‐mAChR in the heart. Recent studies from several laboratories have provided compelling and solid evidence in support of the important roles of M3‐mAChR in regulation and maintenance of cardiac function and in generation and progression of heart disease as well.2 The functions of the cardiac M3‐mAChR revealed thus far include (i) M3‐mAChR regulation of heart rate and cardiac repolarization, (ii) modulation of inotropic effects, (iii) cytoprotection against ischaemic injuries of myocardium, (iv) regulation of cell‐to‐cell communication, and (v) participation in generation and maintenance of atrial fibrillation.3 Signal transduction mechanisms underlying these pathophysiological functions have also been studied, which have allowed us to get insight into the following mechanistic aspects. (i) M3‐mAChR activates a delayed rectifying K+currentIKM3to participate in cardiac repolarization, negative chronotropic actions, and anti‐dysrhythmic (suppresses ischaemic dysrhythmias) as well as pro‐dysrhythmic (facilitates atrial fibrillation) actions. (ii) M3‐mAChR interacts with gap‐junctional channel connexin 43 to maintain cell–cell communication and excitation propagation. (iii) M3‐mAChR regulates intracellular phosphoinositide hydrolysis to improve cardiac contraction and haemodynamic function. (iv) M3‐mAChR activate anti‐apoptotic signalling molecules, enhances endogenous antioxidant capacity, and diminishes intracellular Ca2+overload, all of which contribute to protecting the heart against ischaemic injuries.4 This article provides an overview of the potential roles of the M3‐mAChR in parasympathetic control of heart function under normal physiological conditions and in the setting of a variety of pathological processes including heart failure, myocardial ischaemia and dysrhythmias.
Teaching the Middle Ages on Film: Visual Narrative and the Historical Record
Authors: Driver Martha 
Published: December 2006

AbstractThis article provides an overview of some of the contentious issues concerning the role of film in historical studies of the Middle Ages. Is it appropriate to point out inaccuracies of detail in historical film? As a collective commercial enterprise, is a movie inherently limited in its portrayal of the past, and does this matter? How does film convention affect representation? Can movies err on the side of historical truth? What are the uses of purposeful or intentional anachronism? How have perceptions of movies changed with the advent of the paratext on DVD? How might movies with medieval themes be used effectively in the classroom? Responses to these and related questions are drawn from writings on film from 1915 to the present.
Effect of Cancer Screening and Desirable Health Behaviors on Functional Status, Self‐Rated Health, Health Service Use and Mortality
Authors: Fillenbaum Gerda G. , Burchett Bruce M. , Kuchibhatla Maragatha N. , Cohen Harvey J. , Blazer Dan G. 
Published: December 2006

OBJECTIVES: To determine whether some health behaviors of older people (e.g., obtaining cancer screens) have a limited and others (e.g., exercise) have a broad association with population‐level health status 4 to 6 years later.DESIGN: Longitudinal cohort.SETTING: North Carolina five‐county urban and rural area.PARTICIPANTS: Representative community residents aged 71 and older (Duke Established Populations for Epidemiologic Studies of the Elderly; African American, n=1,256; white, n=974) who provided information on cancer screening and health behaviors.MEASUREMENTS: Demographics, health conditions, functional status, health service use, health insurance. Dependent measures were functional status and self‐rated health 4 years later, hospitalization within 4 years, and death within 6 years. Data were analyzed using descriptive statistics, multivariable logistic regression, and Cox proportional hazards.RESULTS: In fully adjusted analyses, cancer screening had no significant protective association with functional status, self‐rated health, hospitalization, or death. Smoking was a risk factor for hospitalization (odds ratio (OR)=1.48, 95% confidence interval (CI)=1.07–2.05), and death (hazard rate (HR)=1.81, 95% CI=1.47–2.23). Sufficient food reduced hospitalization (OR=0.38, 95% CI=0.15–0.94) and mortality (HR=0.70, 95% CI=0.49–1.02). Regular exercise protected against poor mobility (OR=0.56, 95% CI=0.41–0.77), and poor self‐rated health (OR=0.61, 95% CI=0.45–0.82). Lower activity level increased the hazard of death (HR=1.18, 95% CI=1.03–1.36).CONCLUSION: Disease‐specific screens are important at an individual level but, because of low incidence of condition and comorbidity, may not be associated with population‐level health 4 to 6 years later. Practice of health behaviors with a broader focus is associated, at a population level, with better functional status and self‐rated health and lower rates of hospitalization and death 4 to 6 years later.
Effects of Muscle Strength Training and Megestrol Acetate on Strength, Muscle Mass, and Function in Frail Older People
Authors: Sullivan Dennis H. , Roberson Paula K. , Smith Eugene S. , Price J. Allen , Bopp Melinda M. 
Published: December 2006

OBJECTIVES: To determine the independent and combined effects of progressive resistance muscle strength training (PRMST) and megestrol acetate (MA) on strength, muscle mass, and function in older recuperative care patients.DESIGN: Double‐blind, randomized, controlled intervention using a two‐by‐two factorial design and conducted between 1999 and 2001.SETTING: University‐affiliated Department of Veterans Affairs hospital.PARTICIPANTS: Twenty‐nine patients (mean age 79.4 ± 7.4, 90% white) aged 65 and older and had recent functional decline.INTERVENTIONS: After randomization to one of four treatment groups (low‐resistance exercises plus 800 mg per day of MA or a placebo or high‐intensity PRMST plus 800 mg/d of MA or placebo), subjects received training and the drug or placebo for 12 weeks.MEASUREMENTS: Change in muscle strength, mid‐thigh muscle area, and aggregate functional performance score as assessed using analysis of covariance.RESULTS: Five subjects withdrew from the study before its completion. Based on intent‐to‐treat analyses, subjects who received high‐intensity PRMST and placebo experienced the greatest strength gains. The addition of MA was associated with worse outcomes than with high‐intensity exercise training alone, especially with regard to the leg exercises. Post hoc analysis demonstrated that subjects who received high‐intensity PRMST and placebo experienced significantly greater percentage increases in leg strength than subjects in either of the MA treatment groups (P<.05 for each comparison). There was also a significant negative effect of MA on physical function. In general, subjects who received MA experienced a deterioration in aggregate physical function scores, whereas the remaining subjects improved (−0.80±0.40 vs 0.48±0.41, P=.04). There was not a significant interaction between exercise and MA for any outcome.CONCLUSION: High‐intensity PRMST is a safe and well‐tolerated exercise regimen for frail elderly patients. The addition of MA appears to blunt the beneficial effects of PRMST, resulting in less muscle strength and functional performance gains.