bluuebunny/crossref_metadata_2025_split huggingface dataset:
The counterion–retinylidene Schiff base interaction of an invertebrate rhodopsin rearranges upon light activation
Authors: Nagata Takashi , Koyanagi Mitsumasa , Tsukamoto Hisao , Mutt Eshita , Schertler Gebhard F. X. , Deupi Xavier , Terakita Akihisa 
Published: May 2019

AbstractAnimals sense light using photosensitive proteins—rhodopsins—containing a chromophore—retinal—that intrinsically absorbs in the ultraviolet. Visible light-sensitivity depends primarily on protonation of the retinylidene Schiff base (SB), which requires a negatively-charged amino acid residue—counterion—for stabilization. Little is known about how the most common counterion among varied rhodopsins, Glu181, functions. Here, we demonstrate that in a spider visual rhodopsin, orthologue of mammal melanopsins relevant to circadian rhythms, the Glu181 counterion functions likely by forming a hydrogen-bonding network, where Ser186 is a key mediator of the Glu181–SB interaction. We also suggest that upon light activation, the Glu181–SB interaction rearranges while Ser186 changes its contribution. This is in contrast to how the counterion of vertebrate visual rhodopsins, Glu113, functions, which forms a salt bridge with the SB. Our results shed light on the molecular mechanisms of visible light-sensitivity relevant to invertebrate vision and vertebrate non-visual photoreception.
Tubulin heterogeneity regulates functions and dynamics of microtubules and plays a role in the development of drug resistance in cancer
Authors: Prassanawar Shweta Shyam , Panda Dulal 
Published: May 2019

AbstractMicrotubules, composed of αβ-tubulin heterodimers, exhibit diverse structural and functional properties in different cell types. The diversity in the microtubule structure originates from tubulin heterogeneities, namely tubulin isotypes and their post-translational modifications (PTMs). These heterogeneities confer differential stability to microtubules and provide spatial cues for the functioning of the cell. Furthermore, the altered expressions of tubulin isotypes and PTMs are prominent factors for the development of resistance against some cancer drugs. In this review, we summarize our current knowledge of the tubulin isotypes and PTMs and how, together, they control the cellular functions of the microtubules. We also describe how cancer cells use this tubulin heterogeneity to acquire resistance against clinical agents and discuss existing attempts to counter the developed resistance.
miR-940 potentially promotes proliferation and metastasis of endometrial carcinoma through regulation of MRVI1
Authors: Zhou Zhan , Xu Ya-Ping , Wang Li-Juan , Kong Yan 
Published: May 2019

Abstract
The specific functions and clinical significance of miR-940 in endometrial carcinoma (EC) have not been studied. First, we assessed the expression of miR-940 and MRVI1 in EC tissues collected from The Cancer Genome Atlas (TCGA) database and EC cell lines. miR-940 was significantly overexpressed in EC tissues and cell lines, particularly in RL95-2 cells. Correlation analysis showed that miR-940 expression level was remarkably associated with age, grade, and death. Moreover, the overall survival (OS) rate in the miR-940 low expression group was higher, compared with miR-940 high expression group. Univariate and multivariate models demonstrated that miR-940 expression, stage, and age were predictive indicators of OS. Moreover, there was no significance of the proliferation ability among the three EC cell lines (RL95-2, ISK, and KLE). To reveal the biological roles of miR-940, we respectively transfected RL95-2 cells with miR-940 mimics, miR-940 inhibitors, and control to further investigate the cell proliferation ability, and migration as well as invasion potential of RL95-2 cells. The transfection of miR-940 mimics significantly increased the proliferation and migration/invasion ability of RL95-2 cells. MRVI1 was predicted to be a potential target of miR-940 by means of in silico analysis followed by validation using luciferase reporter assays. MRVI1 was correlated with good prognosis. Moreover, forced expression of MRVI1 in miR-940 mimic transfected cells abolished the facilitation of miR-940 on cell proliferation, migration, and invasion of RL95-2 and KLE cells. In conclusion, our study demonstrates that miR-940 might function as a reliable diagnostic and prognostic signature in EC.
LRRK2, alpha-synuclein, and tau: partners in crime or unfortunate bystanders?
Authors: Outeiro Tiago Fleming , Harvey Kirsten , Dominguez-Meijide Antonio , Gerhardt Ellen 
Published: May 2019

Abstract
The identification of genetic forms of Parkinson's disease (PD) has tremendously expanded our understanding of the players and mechanisms involved. Mutations in the genes encoding for alpha-synuclein (aSyn), LRRK2, and tau have been associated with familial and sporadic forms of the disease. aSyn is the major component of Lewy bodies and Lewy neurites, which are pathognomonic protein inclusions in PD. Hyperphosphorylated tau protein accumulates in neurofibrillary tangles in the brains of Alzheimer's disease patients but is also seen in the brains of PD patients. LRRK2 is a complex multi-domain protein with kinase and GTPase enzymatic activity. Since aSyn and tau are phosphoproteins, we review the possible interplay between the three proteins. Understanding the interplay between LRRK2, aSyn and tau is extremely important, as this may enable the identification of novel targets and pathways for therapeutic intervention.
Endotoxin Induced Fall In Plasma Prekallikrein: Prevention By Prostacyclin And Lignocained
Authors: Scully M F , Weerasinghe K A , Westwick J , Newman Y , Webb P J , Kakkar V V 
Published: May 2019

The infusion of lipopolysaccharide (E.Coli 0111-B4) at a level of l00ng/kg body wt/min for 100 minutes caused a decrease in plasma prekallikrein levels of anaesthetized minipigs. Plasma prekallikrein (PK) in normal pig plasma was measured after cold activation by dextran sulphate using chromogenic substrate S2302. Blood samples were taken into a mixture of EDTA, indomethacin at 20 minute intervals for 3 hours. When infused with endotoxin the PK level decreased to 85% of the preinfusion level after 1 hour (p<0.05) and up to 76% after 2 hours (p<0.05). Significance levels were calculated in relation to the comparable sample in anaesthetized pigs received saline alone. Five pigs were included in each group. Blood pressure, platelet and white cell count also showed significant falls upon infusion of endotoxin.Infusion of lignocaine (20mg followed by 2mg/minute during the course of infusion), an endothelial stabiliser or prostacyclin (125ng/kg/min - a dosage not found to lower blood pressure by more than 5%) prevented the endotoxin induced decrease of PK levels completely as well as the fall in blood pressure. However the thrombocytopenia and leucopenia still occurred. Infusion of a potent thromboxane synthetase inhibitor (7.5mg/min) partially prevented a fall in blood pressure and PK levels.When endotoxin was added to plasma in vitro at concentrations up to lmg/ml no activation of prekallikrein was observed. This observation together with those above suggests that the activation of factor XII by endotoxin in vivo is mediated by primary interaction of endotoxin with endothelium or other vascular cellular elements presumably with the release of procoagulants and/or formation of activating surfaces. Infusion of lignocaine or prostacyclin by stabilizing cell membranes may therefore act to prevent this effect of endotoxin and thereby preclude factor XII activation and bradykinin formation.
Effect Of Negatively-Charged Polyelectrolytes On Plasma Contact Factors And Factor V
Authors: Boffa M C , Faroes J P , Dreyer B P , Pusineri C 
Published: May 2019

The action on plasma clotting of negatively-charged amphipathic polyelectrolytes, derived from copolymerisation of acrylonitrile, was investigated. These polymers were powdered suspended in citrated platelet-poor plasma at different polymer surface/plasma volume ratios. After centrifugation, the plasma supernatant was analyzed.Two opposite effects were observed: an immediate procoagulant effect and a progressive inhibitory one .The first was related to the activation of contact factors. Kinin-forming activity of kininogen as well as prekallicrein activity (measured on chromogenic substrate) were decreased: the former to a greater extent than the latter. However, no significant modification of factor XI and factor XII activities and no decrease of factor XII and HMW Kininogen level (according to immunological criteria) could be evidenced. On the other hand, when the incubation period was prolonged beyond 10 minutes, a progressive lengthening of the recalcification time was observed. This seemed to be due to the concomittant decrease of factor V activity (up to 90 %). In contrast, only a minimal decrease was observed with the same non-charged polymer. This effect was independent of protein C activation, since a similar decrease was also demonstrated after incubating purified human factor V with the negatively-charged polymer.In conclusion, contact factors are not the only ones modified by negative charges; in fact, factor V is particularly sensitive to these polyanions. Consequently, the observed final overall effect is delayed clotting.
Complement Profiles In Disseminated Intravascular Coagulation
Authors: Furukawa Y , Yoshikawa T , Murakami M , Takemura S , Kondo M 
Published: May 2019

Complement levels were examined in cases of disseminated intravascular coagulation (DIC), as well as in experimental animal models of DIC, and it was found that complement played a part either in the development or in the early diagnosis of DIC.Thirteen patients with DIC; 4 associated with bacterial infection, 1 chronic myelogenous leukemia and 8 liver diseases, were serially investigated for their serum complement levels. By the onset of DIC, marked decrease of CH50, C4 and C3 levels were observed in all cases. Those who responded well to anticoagulant therapy revealed a gradual recovery of complement levels, while who failed kept their low serum levels, suggesting that the estimation of complement levels in patients with DIC might be a valuable parameter for their prognosis.Experimental model of DIC was produced in rats by the continuous intravenous infusion of bacterial endotoxin for 4 hours. Histological examination and several coagulation parameters such as fibrinogen, platelet counts, prothrombin time, PTT and FDP confirmed the presence of DIC. The complement
levels, CH50 and C3, were markedly decreased at the onset of DIC and then gradually increased after stopping the infusion of endotoxin. By the pretreatment of rats with heparin, this decrease of serum complement levels by endotoxin was completely prevented.It is concluded that, although many factors have been known to be involved in the production of DIC, complement might also be an important factor, one by contributing to the coagulation process and the other by being affected by secondary fibrinolysis.
Interaction of Prothrombin with phospholipids monolayers In Presence of Ca++
Authors: Lecompte M , Miller I 
Published: May 2019

The activation rate of prothrombin and its conversion into thrombin through a proteolytic degradation is enhanced by phospholipids in the presence of Ca++. In this work, we could elucidate stoechiometric and structural aspects of the interaction between prothrombin, phospholipids and Ca++. We studied the adsorption eguilibria of Ca++and of prothrombin on phospholipids monolayers by a new approach which combines two complementary methods of surface measurement.Electrochemical investigations on lipid monolayer interacting with prothromoin showed penetration of prothrombin in presence or not of Ca++(by increasing the lipid layer capacitance), with a preferential orientation. The adsorption of Ca++and prothrombin to the lipid layer was measured by counting the surface radioactivity of 45Ca and 3H-prothrombin. Synergetic attachment of Ca++and prothrombin to the phospholipid water interface was observed and the number of Ca++per attached prothrombin was determined. The two methods give comparative results for the proposed ionic-hydrophobic interaction.
A New Radioimmunoassay-Technique For Fibrinopeptide-A In Human Plasma
Authors: Harenberg J , Zimmermann R , Haas F , Schmidt-Gayk H 
Published: May 2019

Fibrinopeptide-A (FpA) is thought to be the most sensitive parameter to indicate hypercoagulability with increased fibrin formation in man. Previously described radioimmunoassays for FpA are very time consuming. We present therefore a modification of the assay, which is less time consuming, sensitive, reproducable and reliable. The following modifications were made on the original method: 1. plasma dialysis was omitted 2. performance on microtiter-plates 3. double antibody method.The sensitivity was improved to 0.16 ng FpA / ml plasma. The mean concentration of FpA in dialysed and undialysed plasma did not differ significantly (p<0.001). Effective separation of fibrinogen was achieved by aethanol extraction alone. The mean concentration of FpA correlated highly, when the tracer was separated by charcoal or second antibody (r = 0.96). The recovery was improved to 85%.In healthy persons 0.16-2.5 ng FpA/ml plasma were measured. In patients with venous thrombosis or myocardial infarction in the history FpA was elevated significantly to 2.0 ng/ml-19.6 ng/ml, indicating that the FpA is a usefull tool in diagnosis of hypercoagulability.
Potential Sources of Emboli in Transient Cerebral and Retinal Ischaemia
Authors: de Bono D. , Warlow C. , Hyman N. 
Published: May 2019

91 consecutive patients with transient ischaemic attacks (TIAs) were examined for potential source of emboli using echo cardiography and ambulatory ECG monitoring in addition to clinical examination and angiography. Patients were divided into those with amaurosis fugax and/or carotid TIAs (45),“hemiphenomena” TIAs (26) and vertebrobasilar TIAs (20).“Structural” cardiac defects (of which mitral valve prolapse accounted for just under half) occurred in 34% of patients, significantly more than in age-matched controls. 40% of patients with amaurosis fugax and/or carotid TIAs had carotid artery lesions, as did 30% of those with “hemiphenomena” attacks. 6 patients had both cardiac and carotid lesions. Arrhythmias were detected in 15% of patients and a similar proportion of controls. Hypertension and ischaemic heart disease were more common in the patients.Structural cardiac abnormalities, which may not be haemodynamically significant, might account for cerebral and retinal emboli in about a third of patients presenting with TIAs. The natural history and the most effective therapy of this subgroup require evaluation independently of patients with predominantly carotid atheromatous lesions.
Isolation and Partial Characterization of A Novel Circulating Antithrombin
Authors: Messmore Harry , Parvez Zaheer , Fareed Jawed 
Published: May 2019

We have previously reported on a novel circulating anticoagulant (Clin. Res. 22:396 A, 1974. Thromb. and Haem. 38:77, 1977 (abstr) in a 42 year old female who has had repeated episodes of life threatening hemorrhage since the age of 3. Our preliminary studies showed it to be a protein with some of the properties of a heparin activated antithrombin III. This report is on additional studies to further characterize the inhibitor.The patient’s plasma was fractionated on Sephadex G-200, and the fraction showing immediate acting antithrombin activity was further purified on heparin-sepharose and conconavalin A-sepharose affinity columns. The patient’s inhibitor did not bind to heparin sepharose, and was thus separable from her antithrombin III. It did bind to conconavalin A, and was eluted from the conconavalin A with α - D (+) methylglucoside.It has very broad serine protease inhibitor activity, blocking the hydrolysis of synthetic chromogenic substrates by thrombin, factor Xa, plasmin and trypsin. It did not inhibit Reptilase.Immunochemical assays show it to be α1 antitrypsin. Isoelectric focusing shows it to be a variant of normal, with its isoelectric point being different from a normal control, and pure α1 antitrypsin (commercial, human).The total α1 antitrypsin level in this patient is about 50% of normal, and it has potent immediate acting antithrombin activity. It appears to be similar to a phenotype previously reported as Antithrombin Pittsburgh (Blood 51:129, 1978).
A Rapid and Simple Method for Separation and Analysis of Pure Antihemophilic Factor from Plasma
Authors: Shulman N. R. , Tack K. M. 
Published: May 2019

Current methods of purifying antihemophilic factor (AHF) are complicated and lengthy, leading to marked loss of factor VIII (f VIII) activity despite low temperature processing. Uncertainties concerning denaturation or cryo-aggregation hinder clear interpretation of relationships between the f VIII and von Willebrand factor (vWf) activities of AHF, some suggesting the two activities exist on one molecule, others that two molecules are complexed.Our method utilizes a controlled-pore glass column of pore-size approximately 1000Å. AHF separates as an isolated peak in the void volume while all other proteins including cold insoluble globulin and fibrinogen are retained. We obtain pure AHF, judged by SDS acrylamide gel and immunologic criteria, from large volumes of citrated plasma by a single filtration within one hour of obtaining blood. Processing entirely at 37° or 22° gives the same results. Yields are 40–60% of plasma f VIII activity.Increasing ionic strength (μ) of plasma to >0.3 progressively dissociates vWf and f VIII up to μ = 0.75, vWf remaining at MW >106 while f VIII is retained by pores as small as 330Å, indicating a MW of approximately 1.5 x 105. Human anti-AHF reacts exclusively with separated f VIII, not with vWf; and rabbit anti-AHF reacts primarily with vWf. Findings on normal and hemophilic plasma support the concept that f VIII and vWf are distinct components circulating as a weakly associated complex, and that hemophiliacs lack f VIII by functional and immunologic criteria.Preparation of pure AHF by this technique on a scale appropriate for clinical use is feasible.
On the Primary Structure of Human Fibrinogen
Authors: Henschen A. , Lottspeich F. , Töpfer-Petersen E. , Warbinek R. 
Published: May 2019

The aim of the present investigation is to elucidate the primary structure of human fibrinogen. Through the work of several laboratories including our own large parts of the structure are now known. Here will be reported the complete amino acid sequence of the γ-chain (409 residues). Furthermore, the carbohydrate linkage site in the β-chain and plasmin cleavage sites in the β- and γ-chains have been identified.The peptide chains were isolated by CM-cellulose chromatography following mercaptolysis and alkylation. The γ-chain was cleaved in a way to produce large fragments suitable for automatic sequencing, e. g. with cyanogen bromide or trypsin after citraconylation. The sequences of the isolated fragments allowed reconstruction of the complete sequence of the γ-chain.The carbohydrate linkage site in the β-chain could be isolated by affinity chromatography on concanavalin A-agarose following cleavage of the chain by trypsin or cyanogen bromide. The sequence of 21 amino acid residues around the carbohydrate attachment site was determined.The plasmin cleavage site giving rise to N-terminal glycine in the γ-chain D-fragment was identified. The amino acid sequence linking plasmic fragments E and D in the β-chain was determined.
Factor VIII-Like Activity of Basic Amphoteric Polyelectrolytes
Authors: Exner T. , Rickard K. A. , Kronenberg H. 
Published: May 2019

The broad-range Ampholine (LKB) 3.5–10 containing a mixture of materials with isoelectric points between pH 3.5 and 10 was found to correct the prolonged PTTK of factor VIII-deficient plasma, and this effect was investigated. Ampholines which are used as carrier ampholytes or pH gradient stabilizers in isoelectric focussing are condensation products of propionic acid and polyethylene polyamines.The most effective of the commercial Ampholine mixtures were found to be those with the most alkaline isoelectric points. Ampholine 9–11 at 0.2% concentration was found to have factor VIII and factor IX activity equal to that of normal plasma as well as somewhat less activity as factor XI. It had no significant correcting effect on plasmas deficient in factors V, VII, X, II or XII. In contrast to polyglutamic and polyaspartic acids which have also been reported to correct for factor VIII deficiency in the PTTK, Ampholine 9–11 was effective whether added before or after kaolin contact activation of the test plasma. However, Ampholine 9–11 inhibited contact activation of plasma in the absence of kaolin and showed less correcting activity in partial thromboplastin time tests utilizing activators other than kaolin.
Cross-Linking of Factor VIII by Dimethyl Suberimidate: Structural Implications
Authors: Cockburn C. G. 
Published: May 2019

A dilute solution of highly purified human FVIII was cross-linked by dimethyl suberimidate (negligible intermolecular cross-linking), incubated in 0.2m mercaptoethanol for 35 min. At 37 c, and eluted through a sepharose 4b column. Unreduced SDS-polyacrylamide gel electrophoresis (3.75%:1%) of the material applied to the column showed 6 clear bands believed to represent cross-linked FVIII oligomers (on the grounds that electrophoretic mobility was directly proportional to log oligomer number). The staining intensity of the bands was roughly as follows:(FVIII)1 ≏ (FVIII)2 > (FVIII)3 ≏ (FVIII)4 >(FVIII)5 ≏ (FVIII)6
This indicates that a single FVIII subunit is in intimate proximity with up to 5 other subunits and suggests large areas of close contact between subunits.After cross-linking virtually all the FVIII RAg was lost, but a little FVIIIC (4% yield) eluted at the void volume (Vo) of the sepharose column. No detectable protein in the Vo fraction penetrated very large pore size sds-polyacrylamide gels, indicating a very high molecular weight cross-linked structure.
Ionophoretic Action of Phospholipids on Human Platelets
Authors: Ikeda Y. , Kikuchi M. , Watanabe K. , Ando Y. , Hasegawa M. 
Published: May 2019

The effects of phospholipids on calcium uptake by platelets were examined by using 45CaCl2. Platelet suspensions(3 ̴ 5 × 108/ml) were prepared in PIPES buffer at pH 6.8 and were incubated with 0.2 mM 45CaCl2(10 µCi/ml) in the presence or absence of various kind of phospholipids. The mixtures were centrifuged through silicone oil for 1 min. at 7,000g to separate the pellet. The radioactivity in the pellet was measured with liquid scintillation spectrometer.Among the phospholipids tested, cardiolipin and phosphatidic acid exerted a significant increase of calcium uptake. The amount of calcium translocated into platelets after 60 min. incubation with cardiolipin, phosphatidic acid, sphingomyelin and phosphatidylcholine (0.4 mM) was 2.58, 1.33, 0.30 and 0.32 n mol/109plts, respsctively, while that without phospholipids was 0.31 n mol/109plts. For the sake of comparison, the effect of A23187 or thrombin on calcium uptake was examined. The amount of calcium taken up in the presence of 1 μM A23187 and 1 u/ml of thrombin was 1.84 and 1.33 n mol/109plts, respectively. Calcium uptake was dependent on cardiolipin concentrations and incubation time. LaCl3(1 μM) completely inhibited cardiolipin or A23187 induced calcium influx. However, when platelets were initially incubated with 45CaCl2 for 60 min. in the presence of 0.4 mM cardiolipin followed by addition of 1 μM LaCl3, 50 % of total calcium translocated still remained in platelets indicating that cardiolipin exerted an increase of calcium uptake into both lanthanum-displaceable and non-displaceable pool. Both cardiolipin (0.4 mM) and A23187(1 μM) induced a similar enhancement of platelet aggregation by ADP(2 μM) or epinephrine(1 μg) . LaCl3(1 mM) also inhibited such enhanced aggregabilities. The results suggest that phospholipids may potentiate platelet aggregabilities by their ionophoretic activities.