bluuebunny/crossref_metadata_2025_split huggingface dataset:
The milk ejection reflex in the pig
Authors: Ellendorff F. , Forsling M. L. , Poulain D. A. 
Published: December 2014

1. The milk ejection reflex in response to suckling was studied in conscious sows by continuous recording of intramammary pressure, radioimmunoassay of plasma concentrations of neurohypophysial hormones, and observation of the behaviour of the sows and piglets.2. A regular pattern of nursing, suckling and milk ejection was observed. The mean duration of the suckling period was 6·3 min. Over 144 suckling periods, 113 milk ejections were recorded. Each milk ejection was characterized by a sudden rise in intramammary pressure reaching 20‐49 mmHg, and lasting 8‐41 sec. Milk ejections occurred only once per suckling period, at a mean interval of 44·3 min.3. Each milk ejection occurred with a mean latency of 2·4 min from the onset of a period of initial massage of the udders by the piglets, and was coincident with a period of quiet suckling when the piglets were consuming milk. The onset of nursing was signalled by the sows grunting in a rhythmic manner. In most cases, the frequency of grunts, at first low, increased suddenly 23 sec before milk ejection.4. During eighteen suckling periods leading to milk ejection, neurohypophysial hormone assays performed on serial blood samples showed an increase in plasma concentration of oxytocin up to 30 sec before milk ejection. The concentration of lysine—vasopressin did not rise above basal levels.5. In 21·4% of the suckling periods, no rise in intramammary pressure was observed. In these ‘incomplete sucklings’, the sow usually failed to grunt rapidly, and the piglets obtained no milk. For three of these periods, hormone assay showed no increase in oxytocin or vasopressin concentrations in blood.6. Oxytocin given intravenously produced variations in intramammary pressure which depended on the dose and the rate of injection. Rapid injections of 25‐50 m‐u. oxytocin, caused milk ejections similar to those induced by suckling. When oxytocin was administered at different rates, the faster the injection, the shorter the latency and the higher the amplitude of the response. Plasma concentrations of oxytocin after injection of 25 m‐u. were similar to those observed during reflex milk ejection.7. Trains of electrical pulses were applied to the posterior pituitary of four anaesthetized sows. At frequencies of stimulation above 10 Hz, a rise in intramammary pressure and an increase in plasma oxytocin and vasopressin concentrations were observed. At frequencies of stimulation of 30‐50 Hz, the response of the mammary gland and the time course of the variations in oxytocin plasma concentrations were similar to those observed during natural reflex milk ejection.8. It is concluded that reflex milk ejections during suckling in the pig are caused by the intermittent and spurt‐like release of about 25 m‐u. oxytocin, without concomitant vasopressin release. It is postulated that the release of oxytocin is probably precipitated by a brief and massive activation of oxytocin‐secreting neurones in the hypothalamus. Central mechanisms controlling the intermittent release of oxytocin are discussed.
The effects of low concentrations of cardiotonic steroids on membrane currents and tension in sheep Purkinje fibres
Authors: Hart G. , Noble D. , Shimoni Y. 
Published: December 2014

1. Simultaneous measurements of voltage‐clamp currents and tension were made in shortened sheep Purkinje fibres exposed to various concentrations of strophanthidin, ouabain and digoxin.2. In 5·4 mM‐K moderate doses (mean 2·4 × 10−7M) of the drugs produced an inward shift of the current—voltage relationship at very negative potentials, consistent with an increase in cleft K concentration (Cohen, Daut & Noble, 1976b), which was always accompanied by an increase in tension. This change, which has been attributed to Na—K pump inhibition, was often better correlated with an increase in voltage‐dependent tonic tension than in twitch tension.3. Exposure to dihydro‐ouabain gave a monotonic increase in tension but a delayed increase in inward current. This suggests (cf. Lee, Kang, Sokol & Lee, 1980) that minor changes in pump activity may not always change the current—voltage relationship.4. Low concentrations of strophanthidin (5 × 10−9 to 5 × 10−7 M) produced an outward current shift at very negative potentials, this change becoming smaller with a more rapid onset and reversing on increasing the dose. This change is attributed to pump stimulation.5. The outward current shift was often associated with a negative inotropic effect, which always reversed either spontaneously or on removal of the drug.6. The alternative response at a narrower dose range (1 × 10−8 to 2 × 10−7 M) was an increase in twitch (not tonic) tension, termed the low‐dose positive inotropic effect.7. After a low concentration of cardiotonic steroid had given an early negative inotropic effect the bulk Ca concentration was reduced and the drug re‐applied. The low‐dose positive inotropic mechanism was then observed.8. Outward current shifts and negative inotropy were also obtained with low concentrations of the clinically used glycosides digoxin and ouabain.9. Low concentrations of strophanthidin applied to externally stimulated sheep ventricular trabeculae produced negative inotropy with lengthening of the action potential duration. Positive inotropy and action potential shortening occurred with higher doses.10. A computer model of ionic currents and distributions in Purkinje fibres satisfactorily reproduced the changes in membrane currents and ionic gradients observed with cardiotonic steroids. The only perturbations capable of explaining our results were Na pump stimulation and inhibition.11. It is concluded that cardiotonic steroids possess two inotropic mechanisms. The first is a low‐dose positive inotropic mechanism causally unrelated to changes in sodium pump activity and possibly a direct release of a membrane‐associated calcium fraction. Should this mechanism be unavailable then net pump stimulation at low doses will produce negative inotropy. The second mechanism is the well known Na‐lag process.
Somatic and visceral inputs to the thoracic spinal cord of the cat: effects of noxious stimulation of the biliary system
Authors: Cervero F. 
Published: December 2014

1. Single unit electrical activity has been recorded extracellularly from 133 neurones in the grey matter of the 8th and 9th thoracic segments of the spinal cord in chloralose anaesthetized cats. The responses of these neurones to electrical stimulation of the ipsilateral splanchnic nerve, to natural stimulation of the skin and to distension of the biliary system have been studied.2. Of the neurones studied, 75% responded to electrical stimulation of the splanchnic nerve and had a cutaneous receptive field in the costal region (viscero‐somatic neurones). Twenty‐three per cent of the neurones had a cutaneous receptive field but no visceral input (somatic neurones) and 2% had a visceral input but no cutaneous field.3. Somatic neurones had well‐localized receptive fields from which they could be driven by innocuous stimulation of the skin (52%), by noxious (7%) or by both forms of stimulation (41%). No somatic neurones projected to supraspinal levels via the contralateral ventro‐lateral funiculus.4. Viscero‐somatic neurones were excited by small myelinated and non‐myelinated afferent fibres in the splanchnic nerve. Most viscero‐somatic neurones had cutaneous inputs from nociceptors either exclusively (38%) or in addition to non‐noxious inputs (53%).5. The recording sites of somatic neurones were located almost exclusively in laminae II and IV and dorsal V of the dorsal horn. In contrast, viscero‐somatic neurones were located in lamina I and in laminae V—IX of the grey matter. No differential distribution of recording sites according to type of cutaneous receptive field has been found within the viscero‐somatic group of neurones.6. About one‐third of all viscero‐somatic neurones could be excited by distensions of the biliary system. In all cases, intensities of visceral stimulation above physiological levels were necessary to activate the neurones. Most units driven by biliary afferents were located in or ventral to lamina V of the dorsal horn. The excitation of these units by biliary distension was found to be specifically mediated by receptors in the biliary system.7. Sixteen per cent of the neurones were found to project to supraspinal levels via crossed ventro‐lateral pathways. All of these neurones were viscero‐somatic with axonal conduction velocities between 12 and 68 m sec−1.8. These results are discussed in relation to the postulates of the ‘Convergence‐projection’ theory of referred pain.
Simultaneous visualization of aortic and [3H]5‐hydroxytryptamine‐accumulating cell bodies in the nodose ganglion of the cat
Authors: Gaudin-Chazal G. , Portalier P. , Puizillout J. J. , Vigier D. 
Published: December 2014

1. Single‐ and double‐tracer experiments were performed in cats to investigate the relationship between the aortic cells and the cell bodies accumulating 5‐hydroxytryptamine (5‐HT) in the nodose ganglion. In one series of experiments, horseradish peroxidase (HRP) was applied to the central end of the aortic nerve, anterogradely transported and accumulated in ganglionar perikarya. The distribution of HRP‐positive neurones was reconstructed in serial sections through the nodose ganglion. In a second series of experiments, the distribution of [3H]5‐HT‐accumulating cell bodies was assessed following incubation of the nodose ganglion in [3H]5‐HT. The third series of experiments combined the treatments of the preceding ones: anterograde transport of HRP in the aortic nerve followed by incubation of the nodose ganglion in [3H]5‐HT.2. The results from these experiments provide more information with regard to (i) the topographical relationship between the aortic and [3H]5‐HT‐accumulating cell bodies in the same ganglion and (ii) the distribution and number of double‐labelled neurones, giving further indications about histochemical components of the aortic nerve.3. The HRP experiments demonstrated that HRP‐positive cells show a preferential pattern of topographical organization. They were mostly located in the medial border of the ganglion where the laryngeal and aortic nerves enter. On the other hand, [3H]5‐HT‐accumulating neurones were scattered throughout the ganglion.4. In double‐tracer experiments, three populations of labelled cell bodies were distinguished in the same nodose ganglion: (1) single HRP‐cells; (2) single [3H]5‐HT‐accumulating cells and (3) double‐labelled cells. The distribution of the latter population exhibited no preferential localization. Quantitative estimates indicated that double‐labelled neurones constituted 65‐85% of the population of HRP‐positive cell bodies.5. These results show that most aortic neurones are able to take up exogenous serotonin and may be serotonergic neurones. They suggest that serotonin may be involved in physiological effects mediated via the aortic nerves.
Patch‐clamp studies of slow potential‐sensitive potassium channels in longitudinal smooth muscle cells of rabbit jejunum
Authors: Benham C. D. , Bolton T. B. 
Published: December 2014

1. The patch‐clamp technique was used to study single channel currents in membrane patches of longitudinal smooth muscle cells of rabbit jejunum dispersed by collagenase treatment. Recordings were made from both cell‐attached and isolated patches.2. The predominant unit currents observed were outward at membrane potentials positive to the potassium equilibrium potential (EK) and they were rapidly and reversibly blocked by tetraethylammonium (TEA). Their size varied as EK was changed but was not noticeably affected by changing ENa, ECl or ECa; it was little altered in calcium‐free EGTA solution. Thus, these currents apparently result mainly, if not exclusively, from the movements of potassium ions through channels insensitive to the calcium ion concentration. The present study describes the properties of these potassium channels.3. The unit conductance varied slightly with potential in most experiments; around zero potential it was about 50 pS. The conductance was dependent upon the potassium, but not the calcium, gradient. Sub levels of conductance of about two‐thirds and, less commonly, one‐third of the fully conducting channel state were sometimes seen.4. Membrane patches were studied which showed one to about twelve levels of outward current which were presumed to result from the opening of up to twelve channels having the same characteristics. The probability of channel open state varied with membrane potential, increasing in the potential range ‐40 to +40 mV. Channel openings were rare negative to ‐40 mV. No inward currents through these potassium channels were observed as openings were not seen at membrane potentials negative to EK.5. When the probability of channel opening was low, channel openings occurred in bursts which could be separated by several seconds. Analysis of the openings of a single channel revealed that open times and short closed times were exponentially distributed with mean durations of 15‐45 ms and about 6 ms at zero potential. In some patches regular cyclical openings of several channels occurred. In other patches openings of individual channels appeared to be independent events as they were reasonably fitted by a binomial distribution.6. Following a step change from negative potentials, where channels were closed, to more positive potentials, channel openings increased during a period of 10 s to reach a steady state. No evidence of inactivation was observed.7. These results suggest the existence of a population of potential‐sensitive potassium‐selective ion channels in the smooth muscle cell membrane which are closed at the resting membrane potential and which open upon depolarization with slow (seconds) kinetics; these may be involved in the slow potential (wave) activity of this muscle.
Effect of caffeine on intramembrane charge movement and calcium transients in cut skeletal muscle fibres of the frog
Authors: Kovács L. , Szűcs G. 
Published: December 2014

1. The authors have studied the effect of caffeine in subthreshold concentration (0.5 mmol l−1 at 2‐4 °C) on the contraction threshold, on intramembrane charge movement and calcium transients in voltage‐clamped frog skeletal muscle fibres.2. The single‐gap technique (Kovács & Schneider, 1978) was used for the voltage clamping of terminated segments of cut fibres. Ionic conductances were minimized by using caesium glutamate at the open end pool and tetraethylammonium sulphate and tetrodotoxin at the closed end pool.3. Myoplasmic calcium transients evoked by depolarizing pulses were recorded by measuring the changes in absorbance of the fibres at 720 nm after the intracellular application of Antipyrylazo III dye.4. The strength—duration curve for contraction threshold was shifted towards more negative membrane potentials in the presence of caffeine. Shift was more definite at shorter pulse durations than at the rheobase.5. The total amount of charge moving during the depolarizing pulses at different membrane potentials was not changed by caffeine treatment, whereas the threshold amounts of charge moved during the critical periods of the contraction threshold decreased at different voltages (by about 23%).6. In the presence of caffeine, calcium transients accompanying long (100 ms) depolarizing pulses showed increased voltage‐dependent peak amplitudes, rising phases and rate coefficients referring to calcium release, but a decreased voltage‐dependent re‐uptake rate either during or after the pulse.7. Calcium transients evoked by depolarizing pulses along the strength—duration curve for contraction threshold gave the same peak amplitudes (ranging from 0.9 to 2.8 μmol l−1 free myoplasmic calcium on different fibres), but membrane‐potential‐dependent latency times and rising phases. The rate coefficients for declining phase did not depend on the preceding pulse voltage.8. On applying caffeine, the calcium transients related to the contraction threshold also had equal but smaller peak amplitudes, shorter latency times and the same magnitude of voltage‐independent rate coefficients for the declining phase as in the control solution.9. The twitch potentiating effect of caffeine can be explained by its facilitating calcium release from the sarcoplasmic reticulum, while the re‐uptake rate is not modified. The apparent inhibition of re‐uptake can be related to the enhanced release of calcium due to caffeine effect. Due to the sensitizing effect of caffeine on the sarcoplasmic reticulum membrane, smaller amounts of charge are needed to reach the contraction threshold than without caffeine.
Independent purinergic mechanisms of central and peripheral chemoreception in the rostral ventrolateral medulla
Authors: Moreira Thiago S. , Wenker Ian C. , Sobrinho Cleyton R. , Barna Barbara F. , Takakura Ana C. , Mulkey Daniel K. 
Published: December 2014

AbstractThe rostral ventrolateral medulla oblongata (RVLM) contains two functionally distinct types of neurons that control and orchestrate cardiovascular and respiratory responses to hypoxia and hypercapnia. One group is composed of the central chemoreceptor neurons of the retrotrapezoid nucleus, which provides a CO2/H+‐dependent drive to breathe and serves as an integration centre and a point of convergence of chemosensory information from other central and peripheral sites, including the carotid bodies. The second cluster of RVLM cells forms a population of neurons belonging to the C1 catecholaminergic group that controls sympathetic vasomotor tone in resting conditions and in conditions of hypoxia and hypercapnia. Recent evidence suggests that ATP‐mediated purinergic signalling at the level of the RVLM co‐ordinates cardiovascular and respiratory responses triggered by hypoxia and hypercapnia by activating retrotrapezoid nucleus and C1 neurons, respectively. The role of ATP‐mediated signalling in the RVLM mechanisms of cardiovascular and respiratory activities is the main subject of this short review.
Complete Genome Sequence of the Larval Shellfish Pathogen Vibrio tubiashii Type Strain ATCC 19109
Authors: Richards Gary P. , Needleman David S. , Watson Michael A. , Bono James L. 
Published: December 2014

ABSTRACT

Vibrio tubiashii
is a larval shellfish pathogen. Here, we report the first closed genome sequence for this species (ATCC type strain 19109), which consists of two chromosomes (3,294,490 and 1,766,582 bp), two megaplasmids (251,408 and 122,808 bp), and two plasmids (57,076 and 47,973 bp).
Draft Genome Sequences of Escherichia coli Strains Isolated from Septic Patients
Authors: Dunitz Madison I. , Coil David A. , Jospin Guillaume , Eisen Jonathan A. , Adams Jason Y. 
Published: December 2014

ABSTRACT

We present the draft genome sequences of six strains of
Escherichia coli
isolated from blood cultures collected from patients with sepsis. The strains were collected from two patient sets, those with a high severity of illness, and those with a low severity of illness. Each genome was sequenced by both Illumina and PacBio for comparison.
Genome Sequence of Torovirus Identified from a Pig with Porcine Epidemic Diarrhea Virus from the United States
Authors: Anbalagan Srivishnupriya , Peterson Jessica , Wassman Brent , Elston Josh , Schwartz Karen 
Published: December 2014

ABSTRACT
Porcine torovirus (PToV) strain PToV-NPL/2013 was identified from a pig that tested positive for porcine epidemic diarrhea virus (PEDV). The spike protein-encoding gene from PToV-NPL/2013 had 92% identity with PToV-SH1, suggesting that PToV circulating in the United States is slightly different from the isolates circulating in China. To our knowledge, this is the first report of PToV in the United States.
Draft Genome Sequence of New Bacillus cereus Strain tsu1
Authors: Li Hui , Zhou Suping , Johnson Terrance , Vercruysse Koen , Ropelewski Alexander J. , Thannhauser Theodore W. 
Published: December 2014

ABSTRACT

This paper reports the draft genome sequence of new
Bacillus cereus
strain tsu1, isolated on an agar-cellulose plate. The draft genome sequence is 5.81 Mb, revealing 5,673 coding sequences. It contains genes for cellulose-degradation and biosynthesis pathways of polyhydroxybutyrate (PHB) and 8 rRNA genes (5S, 16S, and 23S).
Full-Genome Sequence of a Reassortant H1N2 Influenza A Virus Isolated from Pigs in Brazil
Authors: Schmidt Candice , Cibulski Samuel Paulo , Muterle Varela Ana Paula , Mengue Scheffer Camila , Wendlant Adrieli , Quoos Mayer Fabiana , Lopes de Almeida Laura , Franco Ana Cláudia , Roehe Paulo Michel 
Published: December 2014

ABSTRACT
In this study, the full-genome sequence of a reassortant H1N2 swine influenza virus is reported. The isolate has the hemagglutinin (HA) and neuraminidase (NA) genes from human lineage (H1-δ cluster and N2), and the internal genes (polymerase basic 1 [PB1], polymerase basic 2 [PB2], polymerase acidic [PA], nucleoprotein [NP], matrix [M], and nonstructural [NS]) are derived from human 2009 pandemic H1N1 (H1N1pdm09) virus.
Draft Genome Sequence of the Organophosphorus Compound-Degrading Burkholderia zhejiangensis Strain CEIB S4-3
Authors: Hernández-Mendoza Armando , Martínez-Ocampo Fernando , Lozano-Aguirre Beltrán Luis Fernando , Popoca-Ursino Elida Carolina , Ortiz-Hernández Laura , Sánchez-Salinas Enrique , Dantán-González Edgar 
Published: December 2014

ABSTRACT

Burkholderia
species are widely distributed in the environment. A
Burkholderia zhejiangensis
strain was isolated from pesticide-contaminated soil from an agricultural field in Mexico and identified as an organophosphorus compound-degrading bacterium. In this study, we report the draft genome sequence of
Burkholderia zhejiangensis
strain CEIB S4-3.
Draft Genome Sequence of the Probiotic Yeast Saccharomyces cerevisiae var.
boulardii
Strain ATCC MYA-796
Authors: Batista T. M. , Marques E. T. A. , Franco G. R. , Douradinha B. 
Published: December 2014

ABSTRACT

Saccharomyces boulardii
is the only yeast approved as a probiotic for human consumption. Here, we report the draft genome sequence of the strain ATCC MYA-796, derived from the French Ultra Levure probiotic drug. The genome has a size of 11.6 Mb with 5,305 putative open reading frames predicted.