bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catecholamine synthesis in rabbit carotid body in vitro
Authors: Fidone S. , Gonzalez C. 
Published: December 2014

1. Catecholamine synthesis in rabbit carotid body was studied in vitro using [3H]DOPA and [3H]tyrosine as precursors. The effects of sympathectomy and transection of the carotid sinus nerve on [3H]dopamine ([3H]DA) and [3H]noradrenaline ([3H]NA) synthesis were investigated in chronically denervated carotid bodies.2. When [3H]DOPA was used as precursor, the synthesis of [3H]DA was linear for more than 6 hr. The carotid body synthesized larger amounts of [3H]catecholamines than when [3H]tyrosine was used as precursor, but most of this excess was liberated into the incubation media. Using 10 μM‐[3H]DOPA as precursor, the synthesis rates were 6·76 and 1·51 n‐mole/g per hr for [3H]DA and [3H]NA, respectively; with 40 μM‐[3H]DOPA, these values increased to 19·22 and 3·23 n‐mole/g per hr, respectively.3. The relationship between [3H]DOPA concentration and [3H]DA synthesis was linear throughout the range 5‐40 μM‐[3H]DOPA.4. Sympathectomy reduced the synthesis of [3H]NA by 90% and [3H]DA by 37% when [3H]DOPA was used as precursor.5. When [3H]tyrosine (40 μM) was used as precursor, synthesis of [3H]catecholamines was linear for at least 4 hr, with rates of 12·10 and 0·85 n‐mole/g per hr for [3H]DA and [3H]NA, respectively.6. [3H]DA and [3H]NA synthesis from [3H]tyrosine exhibited the characteristics of saturable processes, with Km values of 16·8 and 17·6 μM, respectively.7. 6‐methyltetrahydropterine (6‐MPH4, 100 μM), a synthetic analogue of the natural co‐factor for tyrosine hydroxylase, increased [3H]DA and [3H]NA synthesis from [3 H]tyrosine in both the carotid body and superior cervical ganglion, with the greatest effect seen in the carotid body.8. When [3H]tyrosine was used as precursor, sympathectomy of the carotid body reduced [3H]NA synthesis by 80%, but did not alter [3H]DA or [3H]tyrosine levels in the tissue. Transection of the carotid sinus nerve had no effect on [3H]catecholamine synthesis in the carotid body.
Effects of low temperature and terminal membrane potential on quantal size at frog neuromuscular junction
Authors: Cohen I. S. , van der Kloot W. 
Published: December 2014

1. Two mechanisms proposed for the quantal release of acetylcholine (ACh) are: (i) that the quanta are pre‐packaged in vesicles and released by exocytosis and (ii) that the ACh is released from the cytoplasm of the nerve terminal by the opening of an ACh channel. Our experiments were designed to test aspects of these hypotheses.2. Miniature end‐plate currents (m.e.p.c.s) were reversibly decreased in amplitude and increased in duration as the temperature was decreased between 15 and 6 °C. The amplitude decreased with a Q10 of 2·4 between 15 and 11 °C, and then with a Q10 of 3 between 11 and 6 °C. The half‐decay time increased with a Q10 between 4 and 5 over the entire temperature range.3. The effect of temperature on the end‐plate current (e.p.c.) in response to ionophoretically applied ACh was also studied. The e.p.c. in response to a set, sustained dose of ACh was 30% larger at 11 °C than at 15 °C, and about 10% larger at 6 °C than at 15 °C.4. The difference in the end‐plate response to brief pulses of ACh (m.e.p.c.s) and to sustained application of ACh was analysed by Dionne & Stevens (1975). The amplitude of the sustained response depends on both the number of channels opened in the end‐plate, and the length of time they stay open. When our temperature data are analysed in this way, it appears that the amount of ACh/quanta acting on the end‐plate is altered by less than 25% over the temperature range 15‐6 °C.5. From the experiments in which the nerve terminal membrane potential was shifted by external currents it was concluded that miniature end‐plate potential amplitude was independent of the terminal membrane potential (Cooke & Quastel, 1973). This conclusion was confirmed by measuring m.e.p.c.s in low Ca2+ Ringer solution containing 2·0 and 22·0 mM‐KCl; there was no consistent change in m.e.p.c. amplitude.6. The effects of both temperature and terminal membrane potential are more readily interpreted by the vesicle than by the channel hypothesis, since for the channel hypothesis the duration of channel opening should be temperature‐sensitive and the efflux of ACh+ through the terminal membrane should be potential‐dependent.
Influence of luminance gradient reversal on simple cells in feline striate cortex
Authors: Hammond P. , Mackay D. M. 
Published: December 2014

1. The sensitivity of simple cells to luminance gradient reversal in bar stimuli has been investigated in the striate cortex of lightly anaesthetized cats.2. The influence of segment(s) of one polarity of contrast, partially masking or added end‐on to a bar of reversed contrast, was assessed against a stationary textured background (of intermediate average luminance), which was itself without influence on cell behaviour.3. In either configuration, short segments of reversed contrast were suppressive of bar response, to an extent varying with location along the receptive‐field axis, but much greater than predictable from length‐summation characteristics. Response suppression, even by very short segments, was often total.4. The effects of longer segments, added end‐on to a bar of opposite contrast, depended on the extent of length summation exhibited by each cell. With progressive extension of these segments, some recovery of response occurred in a few simple cells with larger receptive fields, but not in small‐field simple cells. The behaviour of end‐stopped simple cells was comparable in all respects to that of their end‐free counterparts, within the length‐summation zone; thereafter, invasion of the inhibitory end‐zones by bars of either polarity elicited a generalized decline in response.5. Where responsiveness was restored by adding longer segments of opposite polarity, the response peak shifted to the discharge centre appropriate to that polarity.6. All these results were found with either polarity of contrast, i.e. a light bar plus dark segments or the converse.7. Similar results were obtained for motion in either direction across the receptive field; and also for flash‐presentation, over either the centre or flanks (whether ‘on’ or ‘off’) of the receptive field.8. The effectiveness of contrasting added segments was assessed as a function of location along the receptive‐field axis for flash‐presented and for moving stimuli. Suppressive effects were greatest over the centre of the receptive field, declining progressively in either direction along its axis, but over greater distances than anticipated from length summation.9. None of the results presented could have been predicted from length‐summation characteristics. They are strongly suggestive of gating, rather than linear, antagonistic interactions.
Hormone‐sensitive magnesium transport in murine S49 lymphoma cells: characterization and specificity for magnesium
Authors: Erdos Joseph J. , Maguire Michael E. 
Published: December 2014

1. The hormone‐sensitive transport of Mg2+ into murine S49 lymphoma cells and its relationship to other divalent cation transport systems have been investigated.2. Mg2+ influx, measured with 28Mg2+, is saturable with an apparent extracellular ion concentration at half‐maximal influx (Kin) for Mg2+ of 330 μM and a maximal influx rate of 360 p‐mole/min.107 cells (2·9 n‐mole/min.mg cell protein or a flux rate of about 0·12 p‐mole/sec.cm2). Efflux of Mg2+ is biphasic with half‐times of 55 and 240 min at 37 °C and is temperature‐sensitive.3. β‐Adrenergic agonists inhibit influx but not efflux of Mg2+ in S49 cells. Efflux of Mg2+ is also unaffected by extracellular [Mg2+] or [Ca2+]. These results imply that the mechanism of the transport system does not involve Mg—Mg exchange.4. Mn2+ is a non‐competitive inhibitor of Mg2+ influx with an inhibition constant, Ki, of about 200 μM. The weak inhibition exhibited by Ca2+ (Ki > 5 mM) is also non‐competitive. La3+ inhibits Mg2+ transport half‐maximally at about 100 μM; Ni2+, Zn2+, Co2+ and Sc3+ are all less effective than La3+. The Ca2+‐channel blockers cis‐diltiazem, verapamil, and nifedipine and the monovalent cations Na+ and K+ also have no effect on Mg2+ influx. However, increasing the extracellular pH stimulates Mg2+ influx.5. Total cellular Mg2+ is about 85 n‐mole/107 cells; however, at apparent isotopic equilibrium with 28Mg2+ less than 3% of total cellular Mg2+ has been exchanged. This indicates that cellular Mg2+ is highly compartmented and that recently transported Mg2+ exchanges very slowly with bulk intracellular Mg2+.6. Ca2+ influx has a Kin of 80 μM and is much slower than Mg2+ influx. Vmax varied in different experiments from 3 to 15 p‐mole/min.107 cells (25‐125 p‐mole/min.mg cell protein). Efflux of Ca2+ is biphasic with half‐times of 22 and 200 min and is temperature‐sensitive. Hormonal stimulation has no effect on either influx or efflux of Ca2+. Mg2+ is a competitive inhibitor of Ca2+ influx (Ki = 3 mM).7. Two kinetic components of Mn2+ influx are present with apparent Kins of 4 μM and 100 μM. Maximal influx rates are 5 and 60 p‐mole/min.107 cells (40 and 480 p‐mole/min.mg cell protein), respectively. Influx of Mn2+ is not altered by β‐adrenergic agonist.8. Uptake of Na+ or K+ is unaltered by β‐adrenergic stimulation.These data in the S49 lymphoma cell indicate that (a) Mg2+ is translocated by a transport system independent of those that transport other divalent cations, (b) hormonal inhibition of divalent ion transport is specific for Mg2+ and (c) cellular Mg2+ is highly compartmented.
Local and systemic effects of tetrodotoxin on the formation and elimination of synapses in reinnervated adult rat muscle
Authors: Taxt Torfinn 
Published: December 2014

1. Polyneuronal innervation of normal and reinnervated fourth deep lumbrical muscle fibres was studied with tension measurements and intracellular recordings. From the tenth day after a complete crush of the muscle nerve, some of the reinnervated muscles were completely paralysed for up to 15 days by local application of tetrodotoxin (TTX) to the sciatic nerve. Other animals received only systemic infusion of TTX during the muscle reinnervation.2. Measurements of tetanic‐tension overlap suggested that about 6% of the muscle fibres in the normal lumbrical muscle were polyneuronally innervated, while intracellular recordings suggested that the percentage was as high as 25%. This discrepancy was mainly due to the presence of one small, sub‐threshold end‐plate potential (e.p.p.) and one large, suprathreshold e.p.p. in almost all polyneuronally innervated muscle fibres.3. Intracellular recordings during muscle reinnervation showed that the extent of polyneuronal innervation reached a maximum of 50% 10‐15 days after denervation and that by 16‐20 days this had decreased to a level similar to that found in normal muscle.4. After a week of total muscle paralysis the extent of polyneuronal innervation had increased to about 80%, estimated by both tension measurements and intracellular recordings. Subsequently, there was no sign of any net elimination of the polyneuronal innervation, even in muscles paralysed for up to two weeks. Many of the polyneuronally innervated fibres were innervated by at least two motor axons. each producing suprathreshold e.p.p.s.5. In muscles contralateral to the paralysed muscles, the extent of polyneuronal innervation reached a maximum of 50% 10‐15 days after denervation as in reinnervated muscles not exposed to TTX. But in contrast to the subsequent decrease in the extent of polyneuronal innervation in animals which received no TTX, this level of polyneuronal innervation persisted in muscles contralateral to the paralysed muscles. The same was true for reinnervated muscles in animals which only received TTX systemically.6. The increased level of polyneuronal innervation after TTX application was not caused by differences in the number of motor units or in number of muscle fibres.7. Paralysed muscles relaxed much more slowly than non‐paralysed muscles at the end of a fused tetanic contraction. The tetanus/twitch ratio of these muscles was also smaller than in contralateral control muscles and the rise time of the twitch was greater.8. It is concluded that a substantial fraction of the fibres in the normal lumbrical muscle of young rats is polyneuronally innervated. After reinnervation, the normal innervation pattern is re‐established, but no net elimination of the polyneuronal innervation occurs unless either nerve or muscle or both are active. A net elimination of synapses is also prevented when TTX is present systemically in low concentrations.
Characterization of Human Papillomavirus Subtype 72b
Authors: Johansson Hanna , Kravtchenko Evgenia , Forslund Ola 
Published: December 2014

ABSTRACT

We report the characterization of human papillomavirus (HPV) subtype 72b of the genus
Alphapapillomavirus
isolated from an oral rinse sample of a healthy woman. The HPV72b L1 open reading frame (ORF) was 90.2% identical to that of HPV72, indicating a subtype close to the border of a novel HPV type.
Evidence Supporting Product Standards for Carcinogens in Smokeless Tobacco Products
Authors: Hatsukami Dorothy K. , Stepanov Irina , Severson Herb , Jensen Joni A. , Lindgren Bruce R. , Horn Kimberly , Khariwala Samir S. , Martin Julia , Carmella Steven G. , Murphy Sharon E. , Hecht Stephen S. 
Published: December 2014

AbstractSmokeless tobacco products sold in the United States vary significantly in yields of nicotine and tobacco-specific nitrosamines (TSNA). With the passage of the Family Smoking Prevention and Tobacco Control Act, the Food and Drug Administration now has the authority to establish product standards. However, limited data exist determining the relative roles of pattern of smokeless tobacco use versus constituent levels in the smokeless tobacco product in exposure of users to carcinogens. In this study, smokeless tobacco users of brands varying in nicotine and TSNA content were recruited from three different regions in the U.S. Participants underwent two assessment sessions. During these sessions, demographic and smokeless tobacco use history information along with urine samples to assess biomarkers of exposure and effect were collected. During the time between data collection, smokeless tobacco users recorded the amount and duration of smokeless tobacco use on a daily basis using their diary cards. Results showed that independent of pattern of smokeless tobacco use and nicotine yields, levels of TSNA in smokeless tobacco products played a significant role in carcinogen exposure levels. Product standards for reducing levels of TSNA in smokeless tobacco products are necessary to decrease exposure to these toxicants and potentially to reduce risk for cancer. Cancer Prev Res; 8(1); 20–26. ©2014 AACR.
Wiskott-Aldrich syndrome iPS cells produce megakaryocytes with defects in cytoskeletal rearrangement and proplatelet formation
Authors: Ingrungruanglert Praewphan , Amarinthnukrowh Pramuk , Rungsiwiwut Ruttachuk , Maneesri-le Grand Supang , Sosothikul Darintr , Shotelersuk Vorasuk , Suphapeetiporn Kanya , Israsena Nipan 
Published: December 2014

SummaryWiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterised by microthrombocytopenia, complex immunodeficiency, autoimmunity, and haematologic malignancies. It is caused by mutations in the gene encoding WAS protein (WASP), a regulator of actin cytoskeleton and chromatin structure in various blood cell lineages. The molecular mechanisms underlying microthrombocytopenia caused by WASP mutations remain elusive. Murine models of WASP deficiency exhibited only mild thrombocytopenia with normal-sized platelets. Here we report on the successful generation of induced pluripotent stem cell (iPSC) lines from two patients with different mutations in WASP (c.1507T>A and c.55C>T). When differentiated into early CD34+ haematopoietic and megakaryocyte progenitors, the WAS-iPSC lines were indistinguishable from the wild-type iPSCs. However, all WAS-iPSC lines exhibited defects in platelet production in vitro. WAS-iPSCs produced platelets with more irregular shapes and smaller sizes. Immunofluorescence and electron micrograph showed defects in cytoskeletal rearrangement, F-actin distribution, and proplatelet formation. Proplatelet defects were more pronounced when using culture systems with stromal feeders comparing to feeder-free culture condition. Overexpression of WASP in the WAS-iPSCs using a lentiviral vector improved proplatelet structures and increased the platelet size. Our findings substantiate the use of iPSC technology to elucidate the disease mechanisms of WAS in thrombopoiesis.
Long-term quality of VKA treatment and clinical outcome after extreme overanticoagulation in 14,777 AF and VTE patients
Authors: Veeger Nic J. G. M. , Khorsand Nakisa , Kluin-Nelemans Hanneke C. , Kooistra Hilde A. M. , Meijer Karina , Piersma-Wichers Margriet 
Published: December 2014

SummaryVitamin K antagonists (VKA) are widely used in atrial fibrillation and venous thromboembolism (VTE). Their efficacy and safety depend on individual time in the therapeutic range (iTTR). Due to the variable dose-response relationship within patients, also patients with initially stable VKA treatment may develop extreme overanticoagulation (EO). EO is associated with an immediate bleeding risk, but it is unknown whether VKA treatment will subsequently restabilise. We evaluated long-term quality of VKA treatment and clinical outcome after EO. EO was defined as international normalized ratio (INR) ≥ 8.0 and/or unscheduled vitamin K supplementation. We included a consecutive cohort of initially stable atrial fibrillation and venous thromboembolism patients. In EO patients, the 90 days pre- and post-period were compared. In addition, patients with EO were compared with patients without EO using a matched 1:2 cohort. Of 14,777 initially stable patients, 800 patients developed EO. The pre-period was characterised by frequent overanticoagulation, and half of EO patients had an inadequate iTTR (< 65 %). After EO, underanticoagulation became more prevalent. Although the mean time between INR-measurements decreased from 18.6 to 13.2 days, after EO inadequate iTTR became more frequent (62 %), p-value < 0.001. A 2.3 times (95 % confidence interval [CI] 2.0–2.5) higher risk for iTTR< 65 % after EO, was accompanied by increased risk of bleeding (hazard ratio [HR] 2.1;CI 1.4–3.2), VKA-related death 17.0 (HR 17.0;CI 2.1–138) and thrombosis (HR 5.7;CI 1.5–22.2), compared to the 1600 controls. In conclusion, patients continuing VKA after EO have long-lasting inferior quality of VKA treatment despite intensified INR-monitoring, and an increased risk of bleeding, thrombosis and VKA-related death.Note: There have been no previous presentations, reports or publications of the complete data that appear in the article. Parts of the data in this article have been presented as a poster at the American Society of Hematology (ASH) congress 2013, New Orleans, United States.
17β-Estradiol Attenuates Hematoma Expansion Through Estrogen Receptor α/Silent Information Regulator 1/Nuclear Factor-kappa B Pathway in Hyperglycemic Intracerebral Hemorrhage Mice
Authors: Zheng Yun , Hu Qin , Manaenko Anatol , Zhang Yang , Peng Yan , Xu Liang , Tang Junjia , Tang Jiping , Zhang John H. 
Published: December 2014

Background and Purpose—
17β-estradiol (E2) has been reported to reduce bleeding and brain injury in experimental intracerebral hemorrhage (ICH) model. However, it is not clear if E2 can prevent early hematoma expansion (HE) induced by hyperglycemia in acute ICH. The aim of this study is to evaluate the effects of E2 on HE and its potential mechanisms in hyperglycemic ICH mice.

Methods—
Two hundred, 8-week-old male CD1 mice were used. ICH was performed by collagenase injection. 50% dextrose (8 mL/kg) was injected intraperitoneally 3 hours after ICH to induce acute HE (normal saline was used as control). The time course of HE was measured 6, 24, and 72 hours after ICH. Two dosages (100 and 300 μg/kg) of E2 were administrated 1 hour after ICH intraperitoneally. Neurobehavioral deficits, hemorrhage volume, blood glucose level, and blood–brain barrier disruption were measured. To study the mechanisms of E2, estrogen receptor α (ERα) inhibitor methyl-piperidino-pyrazole, silent information regulator 1 (Sirt1) siRNA was administered, respectively. Protein expression of ERα, Sirt1, and acetylated nuclear factor-kappa B, and activity of matrix metalloproteinases-9 were detected.

Results—
Hyperglycemia enhanced HE and deteriorated neurological deficits after ICH from 6 hours after ICH. E2 treatment prevented blood–brain barrier disruption and improved neurological deficits 24 and 72 hours after ICH. E2 reduced HE by activating its receptor ERα, decreasing the expression of Sirt1, deacelylation of nuclear factor-kappa B, and inhibiting the activity of matrix metalloproteinases-9. ERα inhibitor methyl-piperidino-pyrazole and Sirt1 siRNA removed these effects of E2.

Conclusions—
E2 treatment prevented hyperglycemia-enhanced HE and improved neurological deficits in ICH mice mediated by ERα/Sirt1/nuclear factor-kappa B pathway. E2 may serve as an alternative treatment to decrease early HE after ICH.
Effect of compression stockings on cutaneous microcirculation: Evaluation based on measurements of the skin thermal conductivity
Authors: Grenier E , Gehin C , McAdams E , Lun B , Gobin J-P , Uhl J-F 
Published: December 2014

Objective To study of the microcirculatory effects of elastic compression stockings. Materials and methods In phlebology, laser Doppler techniques (flux or imaging) are widely used to investigate cutaneous microcirculation. It is a method used to explore microcirculation by detecting blood flow in skin capillaries. Flux and imaging instruments evaluate, non-invasively in real-time, the perfusion of cutaneous micro vessels. Such tools, well known by the vascular community, are not really suitable to our protocol which requires evaluation through the elastic compression stockings fabric. Therefore, we involve another instrument, called the Hematron (developed by Insa-Lyon, Biomedical Sensor Group, Nanotechnologies Institute of Lyon), to investigate the relationship between skin microcirculatory activities and external compression provided by elastic compression stockings. The Hematron measurement principle is based on the monitoring of the skin’s thermal conductivity. This clinical study examined a group of 30 female subjects, aged 42 years ±2 years, who suffer from minor symptoms of chronic venous disease, classified as C0s, and C1s (CEAP). Results The resulting figures show, subsequent to the pressure exerted by elastic compression stockings, an improvement of microcirculatory activities observed in 83% of the subjects, and a decreased effect was detected in the remaining 17%. Among the total population, the global average increase of the skin’s microcirculatory activities is evaluated at 7.63% ± 1.80% ( p < 0.0001). Conclusion The results from this study show that the pressure effects of elastic compression stockings has a direct influence on the skin’s microcirculation within this female sample group having minor chronic venous insufficiency signs. Further investigations are required for a deeper understanding of the elastic compression stockings effects on the microcirculatory activity in venous diseases at other stages of pathology.