bluuebunny/crossref_metadata_2025 huggingface dataset:
Conductance properties of the Na(+)‐activated K+ channel in guinea‐pig ventricular cells.
Authors: Wang Z , Kimitsuki T , Noma A
Published: December 2014

1. The Na(+)‐activated K+ channel current was recorded from inside‐out membrane patches excised from single ventricular cells of guinea‐pig hearts. 2. The single channel current‐voltage relations showed inward‐going rectification with an asymptotic conductance of 180‐210 pS for the inward current at 150 mM [K+]o, when [K+]i was changed between 5.4 and 150 mM. The reversal potential indicated the PNa/PK of about 0.02. 3. The amplitude of outward current was reduced by increasing [Mg2+]i or [Na+]i, but no obvious blocking noise was recorded. The outward current, which remained shortly after quick removal of both [Na+]i and [Mg2+]i, revealed an ohmic conductance of the K+ channel. 4. The [Mg2+]i and [Na+]i block was increased e‐fold by depolarizing the membrane by 49 mV, while the inward current was not blocked. 5. The Na(+)‐activated K+ channel showed frequent subconductance levels. The variance‐mean analysis resolved at least ten major sublevels. The density distribution of the sublevels were measured by composing the conventional amplitude histogram, excluding clear closed state currents, and then dividing the histogram into five segments. The probability of staying in each segment (Pn) was almost always voltage independent, and the grand averages were P1 = 9.5 +/‐ 5.9%, P2 = 6.3 +/‐ 2.1%, P3 = 4.2 +/‐ 1.8%, P4 = 7.8 +/‐ 2.5%, and P5 = 39.3 +/‐ 5.6%, from the lowest segment, respectively. 6. The values of Pn in partially blocked conditions by Na+ and Mg2+ (outward current) were not clearly different from those without any channel block (inward current). The values of Pn, measured before and after applying Ba2+ in the pipette, were also very similar. 7. The above findings indicate that the inward‐going rectification of the Na(+)‐activated K+ channel is due to the Na+ and Mg2+ block. The subconductance of the channel is not due to any channel block by Na+ or Mg2+, but may be attributable to multiple open states of a single‐barrel channel, which has a large conductance. The channel may be blocked from any open conformation with an equal probability and with very fast kinetics.
Postnatal changes in motoneurone electrotonic coupling studied in the in vitro rat lumbar spinal cord.
Authors: Walton K D , Navarrete R
Published: December 2014

1. Electrotonic coupling between motoneurones innervating ankle flexor and extensor muscles, as well as between unidentified lumbar motoneurones, was studied using intracellular recordings in an in vitro spinal cord‐hindlimb preparation isolated from rats between birth (P0) and 13 days (P13). 2. Graded ventral root stimulation could elicit graded, short latency depolarizations (SLD) which preceded, coincided with, or followed the antidromic action potential. These SLDs were identified as electrotonic junctional potentials by their latency, relative insensitivity to changes in membrane potential and their resistance to one or more of the following: (1) high‐frequency stimulation, (2) collision with a somatofugal action potential, (3) removal of Ca2+ from the bathing solution. 3. SLDs were studied in 162 neurones and were identified in 77.2% of the cells in preparations from P0 to P3 rats (n = 57), but only in 30.8% at P8 to P13 (n = 39). 4. SLDs were largest in the youngest animals (P0 to P3), decreasing from a mean of 1.31 mV (+/‐ 0.17, n = 34) to 0.56 mV (+/‐ 0.10, n = 7) at P8 to P13. The SLDs comprised two to eight (4.3 +/‐ 0.36) all‐or‐none components as determined from twenty collision experiments. 5. Electrotonic coupling between motoneurones was specific. SLDs could be elicited in given motoneurones by stimulation of their homonymous but never of their antagonistic muscle nerves. 6. These results indicate that electrotonic coupling between lumbar motoneurones in neonatal animals exhibits a high degree of specificity and that its significance, as judged by the amplitude and frequency of occurrence of SLDs, decreases postnatally at a rate that can be correlated with the functional maturity of the motoneurones and the muscular system.
Changes in tetanic and resting [Ca2+]i during fatigue and recovery of single muscle fibres from Xenopus laevis.
Authors: Lee J A , Westerblad H , Allen D G
Published: December 2014

1. Single muscle fibres were dissected from the toe muscles of Xenopus laevis and microinjected with Fura‐2 to measure myoplasmic calcium concentration ([Ca2+]i). Injected fibres were illuminated at 340 and 380 nm and the ratio of the resulting fluorescence at 505 nm (the Fura‐2 ratio) was taken as a measure of [Ca2+]i. Fibres were fatigued at 21 degrees C by repeated tetani until developed tension had fallen to 50% of control. 2. Tetanic tension declined monotonically during fatiguing stimulation, whereas the tetanic Fura‐2 ratio first increased and then declined. At the 10th tetanus, tension was 87% of control whereas the Fura‐2 ratio was 106% of control. At the end of fatiguing stimulation, where tension was around 50% of control, the tetanic Fura‐2 ratio was reduced to 71%. The rate of decline of both tension and the Fura‐2 ratio after a tetanus slowed during fatigue. During recovery, the tension and the tetanic Fura‐2 ratio recovered in parallel. 3. The resting Fura‐2 ratio increased throughout fatigue reaching 237% of control when tension had declined to 50%. There was a rapid phase of recovery, complete within 1 min, by which time the resting Fura‐2 ratio was 198% of control. Subsequent recovery was slower and took 20‐30 min to reach a stable level which was 121% of control. 4. The resting Fura‐2 ratio towards the end of fatiguing stimulation was greater than the tetanic Fura‐2 ratio in the early part of recovery although there was no detectable increase of resting tension during fatiguing stimulation. This observation suggests that the Ca2+ sensitivity of the contractile proteins was reduced at the end of fatiguing stimulation. 5. Plots of the tetanic tension against tetanic Fura‐2 ratios throughout fatiguing stimulation and recovery also suggested that Ca2+ sensitivity was reduced during fatiguing stimulation when compared to recovery. 6. The increases in resting [Ca2+]i caused by raised [K+]o (from 2.5 to 10 mM) and/or by application of 15% CO2 were much less than those produced by fatiguing stimulation. Much of the elevated [Ca2+]i in fatigue could be reversed by application of dantrolene (25 microM). 7. The results suggest that both reduced tetanic [Ca2+]i and reduced Ca2+ sensitivity contribute to the decline of tension during fatigue.(ABSTRACT TRUNCATED AT 400 WORDS)
The effects of Ca2+, Mg2+ and kynurenate on primary afferent synaptic potentials evoked in cat spinal cord neurones in vivo.
Authors: Walmsley B , Nicol M J
Published: December 2014

1. A technique was developed for perfusing the central canal of the cat spinal cord over a defined region to alter the extracellular environment and examine the effects of various ions and pharmacological agents on synaptic transmission in vivo. 2. Monosynaptic excitatory postsynaptic potentials (EPSPs) evoked by hindlimb muscle nerve stimulation were recorded intracellularly from dorsal spinocerebellar tract (DSCT) neurones in Clarke's column, in close proximity to the central canal. 3. The effects of central canal perfusion of solutions containing Ca2+, Mg2+ and kynurenate on the monosynaptic afferent EPSP were examined. 4. Perfusion of the central canal with solutions containing a high Mg2+ concentration completely and reversibly blocked the monosynaptic EPSP, while perfusion with solutions containing a high Ca2+ concentration produced up to a fourfold increase in the peak amplitude of the EPSP. This large increase in the EPSP indicates that the pool of quanta available for release is considerably greater than estimated from previous quantal analysis studies at this synaptic connection. 5. Perfusion of the central canal with kynurenate, an antagonist at excitatory amino acid receptors, resulted in a complete block of the monosynaptic EPSP in DSCT neurones. This provides direct evidence that an excitatory amino acid, such as glutamate, is released from primary muscle afferent terminals in Clarke's column of the cat spinal cord in vivo.
Development of the lung liquid reabsorptive mechanism in fetal sheep: synergism of triiodothyronine and hydrocortisone.
Authors: Barker P M , Walters D V , Markiewicz M , Strang L B
Published: December 2014

1. Thyroidectomy was performed on twelve fetal sheep between 111 and 115 days gestation. Measurement of fetal lung liquid secretion and absorption rates (Jv) were made at rest and during short (45 min) and long (5 h) infusions of adrenaline (0.5 micrograms/min) in a total of thirty‐seven experiments, some in the absence of triiodothyronine (T3) and hydrocortisone and some at set times after the administration of the two hormones. 2. T3 was given either as an I.V. infusion (60 micrograms/24 h) or as a bolus of 30 micrograms; hydrocortisone was given as an infusion of 10 mg/24 h. Both hormones were administered together. 3. Before T3 and hydrocortisone were given short infusions of adrenaline had no effect on Jv but 4 h after exposure to the hormones secretion rate was reduced to near zero (Jv = ‐0.5 +/‐ 1.6 ml/h, n = 4) by adrenaline; after 24 h of hormone exposure, absorption of fetal lung liquid was produced by adrenaline (Jv = ‐3.6 +/‐ 2.2 ml/h, n = 4) which was even greater after 72 h, (Jv = ‐11.2 +/‐ 2.2 ml/h, n = 4). 4. During long infusions of adrenaline when T3 and hydrocortisone were given at the start of the experiment, an effect on lung liquid secretion was evident at 2 h and absorption was produced at 4 h (Jv = ‐4.2 +/‐ 2.5 ml/h, n = 3). The effect was significantly different from control long infusions of adrenaline performed the previous day in the absence of hormones. 5. After 24 or 48 h of stopping T3 and hydrocortisone administration, adrenaline no longer produced absorption of lung liquid, indicating that the effect of the two hormones was reversible within 24‐48 h. 6. The protein synthesis inhibitor cycloheximide put into lung liquid (4 x 10(‐5) to 3 x 10(‐4) M) blunted the effect of the hormones at 4 h and prevented absorption of lung liquid at 24 h. Jv during adrenaline was ‐3.6 +/‐ 1.5 ml/h in control experiments but was +3.3 +/‐ 0.9 ml/h after cycloheximide, n = 4, P < 0.01. This indicated that the two hormones produced their effect through protein synthesis.
Effects of calcitriol on stimulation of ion transport in pig jejunal mucosa.
Authors: Schröder B , Kaune R , Harmeyer J
Published: December 2014

1. Active sodium (Na+) and chloride (Cl‐) fluxes were studied in vitro in Ussing‐type chambers with stripped jejunal mucosa of piglets which suffered from pseudo‐vitamin D deficiency rickets, type I. The piglets are devoid of renal calcitriol (1,25‐dihydroxy vitamin D3) production and have only small amounts of calbindin in their jejunal enterocytes. 2. In the presence of 0.01 mM‐indomethacin non‐stimulated short‐circuit current (Isc), transepithelial potential difference (PD), tissue conductance (Gt) and unidirectional Na+ (JNa) and Cl‐ fluxes (JCl) were not affected by the low calcitriol (LC) concentration in plasma. 3. Adding 10 mM‐theophylline to the serosal solution in the presence of 0.01 mM‐indomethacin caused significantly greater increases in Isc in LC mucosa than in mucosa of vitamin D3‐treated and control piglets with normal calcitriol (NC) concentrations in plasma. Omission of indomethacin significantly increased Isc stimulation provoked by theophylline with LC and NC mucosa. The increase, however, was significantly greater with LC than with NC mucosa. 4. Omission of calcium (Ca2+) from the serosal bathing solution significantly depressed Isc stimulation by 10 mM‐theophylline in indomethacin‐treated LC and NC mucosa. But depression was greater with LC than with NC mucosa. 5. Blocking Ca2+ entry into the cytosol by adding either 0.1 mM‐TMB‐8 or 0.5 mM‐d,l‐verapamil to the serosal bathing solution abolished the difference in Isc response to theophylline between indomethacin‐treated LC and NC mucosa due to greater depression of Isc in LC than in NC mucosa. 6. The combined effects of theophylline and A23187 on Isc stimulation were calcitriol dependent. In the presence of indomethacin this dependence was only significant when A23187 was given prior to theophylline. In the absence of indomethacin the combined effects of A23187 and theophylline on Isc were always significantly greater in LC than in NC mucosa, irrespective of the order of adding the two agents. 7. Addition of theophylline stimulated net Na+ and Cl‐ secretion in indomethacin‐treated LC and NC mucosa. The increases of net Na+ and Cl‐ fluxes fully accounted for the rise of Isc with NC mucosa but accounted only partly for the increase in Isc with LC mucosa. This resulted in significant increase in theophylline‐stimulated residual ion flux (JR) in LC mucosa which probably resulted from enhanced secretion of bicarbonate.(ABSTRACT TRUNCATED AT 400 WORDS)
Release of dopamine and chemoreceptor discharge induced by low pH and high PCO2 stimulation of the cat carotid body.
Authors: Rigual R , López-López J R , Gonzalez C
Published: December 2014

1. Cat carotid bodies were incubated with the precursor [3H]tyrosine to label the catecholamine deposits and then mounted in a superfusion chamber which allowed simultaneous collection of the released [3H]dopamine (DA) and recording of action potentials from the carotid sinus nerve. 2. Low pH (7.2‐6.6) superfusion of the carotid bodies for periods of 10 min produced a parallel increase in the release of [3H]DA and chemoreceptor discharge. 3. Carotid sinus nerve denervation of the carotid body 12‐15 days prior to the experiments did not modify the release of [3H]DA elicited by low pH. 4. Superfusion of the carotid bodies with Ca(2+)‐free, high‐Mg2+ (1.6 mM) media reduced basal release of [3H]DA and chemoreceptor discharge by about 30%. Release evoked by low pH was reduced by 82%. Peak and average chemoreceptor discharge recorded in response to low pH were reduced by 28%. 5. Solutions containing weak acids (sodium acetate, 10 mM), adjusted at pH 7.4, elicited release of [3H]DA and increased chemoreceptor discharge. 6. With HCO3‐CO2‐buffered superfusion media, a reduction of bicarbonate to 5.6 mM (pH 6.8), an increase in CO2 to 20% (pH 6.8), or a simultaneous increase in CO2 to 20% and bicarbonate to 90 mM (pH 7.4), resulted in all cases in a corresponding increase in [3H]DA release and chemoreceptor discharge. The most effective stimulus was 20% CO2‐pH 6.8 and the least effective 5% CO2‐5.6 mM‐HCO3‐pH 6.8. 7. Inhibition of carbonic anhydrase with acetazolamide while perfusing the carotid bodies with a 20% CO2‐equilibrated (pH 7.4) solution resulted in comparable reductions in the release of [3H]DA and chemoreceptor discharge. 8. It is concluded that the effective acidic stimulus at the carotid body chemoreceptors is an increase in hydrogen ion concentration in type I cells. It is also concluded that DA plays a critical role in the genesis of carotid sinus nerve discharges.
Ionic mechanisms for the transduction of acidic stimuli in rabbit carotid body glomus cells.
Authors: Rocher A , Obeso A , Gonzalez C , Herreros B
Published: December 2014

1. The release of [3H]dopamine (DA) in response to inhibition of the Na+ pump or to intracellular acid load was studied in rabbit carotid bodies (CB) previously incubated with the precursor [3H]tyrosine. The ionic requirements of the release response and the involvement of specific ion transport systems were investigated. 2. Inhibition of the Na+ pump, by incubating the CB with ouabain or in K(+)‐free medium, evokes a DA release response which requires the presence of Na+ and Ca2+ in the medium and is insensitive to nisoldipine. This suggests that the response is triggered by entry of external Ca2+ through Na(+)‐Ca2+ exchange, a consequence of the increase in intracellular Na+ resulting from inhibition of the pump. 3. Incubation of the CB in medium equilibrated with 20% CO2 at pH 6.6, or in medium containing the protonophore dinitrophenol (DNP) or the weak acid propionate, elicits a DA release response which requires also the presence of Na+ and Ca2+ in the medium and is insensitive to dihydropyridines. 4. Ethylisopropylamiloride (EIPA), an inhibitor of the Na(+)‐H+ exchanger, markedly decreases the release response elicited by DNP or propionate in bicarbonate‐free medium, but has not any effect in bicarbonate‐buffered medium. In the latter condition, the EIPA‐insensitive release of DA is inhibited by reducing the HCO3‐ concentration in the medium to 2 mM or by removal of Cl‐, suggesting that in bicarbonate‐buffered medium a Na(+)‐dependent HCO3(‐)‐Cl‐ exchanger is involved in the release response. 5. It is concluded that the release of DA by the chemoreceptor cells in response to acidic stimulation is triggered by entry of external Ca2+ through Na(+)‐Ca2+ exchange. This exchange is promoted by the increase of intracellular Na+ that results from the operation of Na(+)‐coupled H(+)‐extruding mechanisms activated by the acid load.
Response properties of cones from the retina of the tiger salamander.
Authors: Perry R J , McNaughton P A
Published: December 2014

1. Spectral sensitivity measurements using the suction electrode technique reveal three types of cone in the retina of the tiger salamander, showing maximum sensitivity at wavelengths 610 nm (red‐sensitive cone), 444 nm (blue‐sensitive cone) and below 400 nm (UV‐sensitive cone). 2. The absolute sensitivities of red‐ and blue‐sensitive cones to flashes of optimal wavelength are 0.022 and 0.33 pA photon‐1 micron 2 respectively. 3. The time‐to‐peak of the dim flash response and the recovery of membrane current after a flash of any intensity are fastest in red‐sensitive and slowest in blue‐sensitive cones. 4. In blue‐ and UV‐sensitive cones the flash response peaks progressively earlier as the flash strength is increased, as in rods. In red‐sensitive cones, however, bright flash responses take longer to peak than dim flash responses. 5. In all three cone types, voltage clamping at ‐40 mV reduces the time‐to‐peak of the response to a bright flash, showing that the rising phase of the bright flash response is normally limited by the time constant of the cell. Under voltage clamp, all cones show a decrease in time‐to‐peak with increasing flash intensity. 6. Voltage clamping red‐sensitive cones reveals two components of the rising phase of the response to a bright flash. Most of the current is rapidly suppressed by a bright flash, and represents the closure of light‐sensitive channels. The residual current decays with a mean time constant of 20 ms, and is probably attributable to the decline of electrogenic Na(+)‐Ca2+, K+ exchange. The amplitude of this exchange current suggests that the proportion of the dark current carried by calcium ions is greater in red‐sensitive cones than in rods of the same species. 7. In UV‐sensitive cones, a prominent oscillation of light‐sensitive current is observed during the recovery from flashes of intermediate intensity. A similar, but slower and less prominent oscillation is usually seen in blue‐sensitive cones. 8. When a red‐sensitive cone is voltage clamped an oscillation similar to those in the other two cone types is revealed. An underswing of up to 2 pA is also observed after recovery from intermediate or bright flashes in the majority of red‐sensitive cones, and voltage clamping increases the amplitude of this underswing.(ABSTRACT TRUNCATED AT 400 WORDS)
Regulation of spontaneous opening of muscarinic K+ channels in rabbit atrium.
Authors: Kaibara M , Nakajima T , Irisawa H , Giles W
Published: December 2014

1. Intracellular mechanism(s) for controlling the opening of muscarinic K+ channels in the absence of an applied muscarinic agonist were studied in rabbit atrium by applying the patch clamp technique to isolated single myocytes. 2. In the cell‐attached patch configuration, currents due to the activity of both the muscarinic K+ channel and the inward rectifying K+ channel were recorded. However, while the inward rectifying K+ channel currents were observed in only ten patches of 211 examined, spontaneous opening (i.e. in the absence of a muscarinic agonist) of the muscarinic K+ channel currents was observed in all patches examined in these atrial cells. 3. The single‐channel currents due to spontaneous opening of muscarinic K+ channels were identified on the basis of their very similar conductance and gating properties to the unitary events which have been recorded when 0.5 microM‐acetylcholine is included in the pipette and 10 microM‐GTP is present in the internal side of the patch membrane. 4. Although the spontaneous opening of the muscarinic K+ channels disappeared soon after excision of the patch membrane, this type of channel activity reappeared following application of ATP and MgCl2 to the internal side of the torn‐off patch, as expected from previous publications. 5. The K+ channel activity induced by the ATP and Mg2+ (measured as the product of the number of channels, N, times the probability of opening, Po) was strongly dependent upon concentration of free Mg2+; it was half‐maximal at 2.2 x 10(‐4) M [Mg2+]i. However, after the muscarinic K+ channels had been activated by 100 microM‐guanosine 5'‐O‐3‐thiotriphosphate (GTP gamma S) together with ATP and Mg2+, an increase in the Mg2+ concentration from 5.5 x 10(‐5) to 2 x 10(‐3) M failed to enhance this channel activity. 6. Pertussis toxin, which is known to uncouple muscarinic receptors from associated G‐proteins (G(i) or G(o)), failed to inhibit the ATP‐ and Mg(2+)‐induced activation of this K+ channel in the absence agonists. 7. In experiments made to test whether the Mg(2+)‐ATP requirement results from an obligatory phosphorylation reaction, ATP was replaced with adenylyl‐imidodiphosphate (AMP‐PNP), an analogue of ATP which is resistant to hydrolysis. This K+ channel activity was not present when ATP was replaced with AMP‐PNP.(ABSTRACT TRUNCATED AT 400 WORDS)
Mechanisms underlying potentiation of synaptic transmission in rat anterior cingulate cortex in vitro.
Authors: Sah P , Nicoll R A
Published: December 2014

1. The properties of the excitatory synapse made by callosal inputs onto layer V and layer VI cells in the anterior cingulate cortex were studied in an in vitro slice preparation with intracellular recording. 2. In the presence of picrotoxin, the excitatory postsynaptic potential (EPSP) had two components, a fast component blocked by the non‐N‐methyl‐D‐aspartate (NMDA) receptor antagonist 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione (CNQX) and a slow component blocked by the NMDA receptor antagonist DL‐2‐amino‐5‐phosphonovalerate (APV). 3. Delivery of a brief tetanus to the afferent fibres led to a long‐term potentiation (LTP) of the initial slope of the monosynaptic EPSP. The LTP displayed the property of co‐operativity and could be blocked by APV or by buffering intracellular calcium. 4. Pairing of low frequency presynaptic activity or weak tetanic stimulation with postsynaptic depolarization failed to potentiate the EPSP. This suggests that postsynaptic depolarization alone is unable to explain the co‐operativity. 5. It is concluded that the transmitter mediating the excitatory input between callosal afferents and layer V and layer VI pyramidal neurones is glutamate. Tetanic stimulation of these afferents leads to LTP which shares many but not all the properties of LTP seen in the CA1 region of the hippocampus.
Modulation of voltage‐activated channels by calcitonin gene‐related peptide in cultured rat neurones.
Authors: Zona C , Farini D , Palma E , Eusebi F
Published: December 2014

1. Whole‐cell currents were recorded from cultures of dissociated neocortical neurones of the rat. Rat alpha‐calcitonin gene‐related peptide (CGRP; 1 nM‐1 microM) caused significant dose‐dependent decreases in the voltage‐activated transient (A‐current) and delayed rectifier K+ currents. Forskolin (10 nM‐20 microM) mimicked this effect. Peak K+ currents were gradually decreased after loading neurones with cyclic AMP (100 microM) through patch pipettes. CGRP was ineffective in neurones loaded with cyclic AMP. 2. CGRP (0.5‐2 microM) increased cytosolic cyclic AMP concentration and this effect was mimicked by forskolin (5‐40 microM). 3. CGRP (0.1‐1 microM) reduced high‐threshold Ca2+ currents; as did forskolin (5‐20 microM) and cyclic AMP loaded into the neurones. In contrast, low‐threshold Ca2+ currents were not affected by any of these agents. 4. Voltage‐activated Na+ currents were significantly reduced by both CGRP (0.1‐1 microM) and forskolin (5‐20 microM). A similar effect was observed when cells were loaded with cyclic AMP. 5. We conclude that, in neocortical neurones, CGRP attenuates voltage‐activated currents by stimulating the intracellular cyclic AMP signalling system.
Potassium currents of isolated Necturus enterocytes: a whole‐cell patch‐clamp study.
Authors: Sheppard D N , Valverde M A , Giraldez F , Sepúlveda F V
Published: December 2014

1. The whole‐cell recording mode of the patch‐clamp technique was used to investigate the ionic currents of enterocytes isolated from the small intestine epithelium of Necturus maculosus. 2. When enterocytes were bathed in a physiological Ringer solution and dialysed with a K(+)‐rich intracellular solution containing 1.5 x 10(‐7) M intracellular Ca2+, strongly outwardly rectifying currents were observed. These currents were absent from enterocytes internally dialysed with K(+)‐free solutions. 3. The kinetics of activation of the outwardly rectifying current was monoexponential with rate constants decreasing with depolarization from 160 ms at 20 mV to 40 ms at 60 mV. Similar voltage dependence of the relaxations after activation were observed. 4. Strongly buffering intracellular Ca2+ with EGTA inhibited outward currents, while increasing Ca2+ increased both their magnitude and rate of activation. 5. Bath application of the K+ channel inhibitors Ba2+ and TEA greatly attenuated outwardly rectifying currents. This observation plus the fact that tail currents reverse near EK points to K+ as the charge carrier in these currents. 6. Outside‐out patches showed maxi K+ channels and lower conductance K+ channels. Averaging fluctuations of the maxi K+ channels gave a kinetic behaviour similar to the whole‐cell currents.
Prostaglandin E2 is involved in adrenocorticotrophic hormone release during swimming exercise in rats.
Authors: Watanabe T , Morimoto A , Sakata Y , Long N C , Murakami N
Published: December 2014

1. We found that adrenocorticotrophic hormone (ACTH) release in rats induced by acute swimming exercise or by an intravenous injection of human recombinant interleukin‐1 beta (IL‐1 beta) was significantly attenuated after chronic exercise. 2. Since involvement of prostaglandins in the ACTH response induced by IL‐1 is well known, we investigated the effect of indomethacin, an inhibitor of prostaglandin synthesis, on the ACTH response induced in rats by acute swimming exercise. Pretreatment with an intravenous injection of indomethacin significantly suppressed the ACTH response induced by exercise. The effect of indomethacin (1 and 10 mg/kg) on the ACTH response was dose‐dependent. 3. The effect of chronic exercise on the exercise‐induced changes in the plasma concentration of prostaglandin E2 was investigated. The plasma concentration of prostaglandin E2 significantly increased after acute exercise in both the control and the chronically exercised rats. However, the increase in the plasma level of prostaglandin E2 was significantly smaller in the chronically exercised group than in the control group. 4. Intravenous injections of prostaglandin E2 produced dose‐dependent increases in the plasma concentration of ACTH in rats. 5. The present results suggest that an increase in prostaglandin E2 levels in plasma is involved in the development of the ACTH response induced by exercise.
Sensor Placement Analysis for Fault Detectability and Isolability of an Automated Manual Transmission
Authors: Chen Qi , Ahmed Qadeer , Rizzoni Giorgio
Published: December 2014

This paper presents a systematic methodology to identify the sensor placements to maximize the detection and isolation of faults that can affect the performance of Automated Manual Transmissions (AMT). A set of critical faults has been identified using Failure Mode and Effects Analysis (FMEA). A detailed fault modeling has been performed for AMT and the model has been simulated to demonstrate the faults effect on AMT functions. The structurally over-determined part of AMT is determined using the concepts of structural analysis that utilizes AMT structural model. The analysis assists in shortlisting the critical sensors locations for health monitoring of AMT. The results show that the proposed sensors set is economical and the sensor locations ensure the detectability and isolability of the critical faults.
Design Modeling and Control of a Lab-Scale Compressed Air Energy Storage (CAES) Testbed for Wind Turbines With Simulated Input and Demand Power Variability
Authors: Shirazi Farzad A. , Gagnon Pieter , Li Perry Y. , Van de Ven James D.
Published: December 2014

A Compressed Air Energy Storage (CAES) test-bed has been developed to experimentally demonstrate the energy storage concept proposed in [1] for offshore wind turbines. The design of the testbed has been adapted to the available air compression/expansion technology. The main components of the system consist of an open accumulator, a hydraulic pumpmotor, air compressor/expander, an electrical generator and load, a differential gearbox and a hydraulic control valve. These components are first characterized and then a dynamic model of the system has been developed. The objective is to regulate the output current/voltage of the generator while maintaining a constant accumulator pressure in the presence of input and demand power variations in the system. This is achieved by Proportional-Integrator (PI) control of pumpmotor displacement and field current of the generator. The stability of these controllers has been proved using an energy-based Lyapunov function. Experimental results for storage and regeneration modes have been presented showing excellent performance of the system in response to power disturbances.
Towards a Robotic Hand Rehabilitation Exoskeleton for Stroke Therapy
Authors: Kim Yeongjin , Cheng Shing Shin , Ecins Aleksandrs , Fermüller Cornelia , Westlake Kelly P. , Desai Jaydev P.
Published: December 2014

A majority of stroke patients suffer from the loss of effective motor function, which compromises their ability to control grasping motion. Hand rehabilitation is therefore important to improve their motor function and quality of life in activities of daily living (ADLs). In this initial work, we present the design and development of a partial hand exoskeleton actuated by shape memory alloy (SMA) spring actuators. The SMA spring actuators are cooled by forced convection and the individual joints of the finger are actuated via tendons. In this design, pre-tension in the passive springs enables the restoration of the original configuration when the SMA springs are not actuated. To address the slow cooling rate of SMA springs that limits the control performance, we developed a cooling unit for each SMA spring actuator. We utilized computer vision to identify an object and provide 3-D coordinates of the optimal grasping points on the object. We then utilized vision-based control to move the fingertips towards the grasping points. The experimental results showed that each individual joint was able to return to its original configuration significantly faster as well as to follow a sinusoidal trajectory with the proposed cooling strategy.
Non-Linear Control of Tilting-Quadcopter Using Feedback Linearization Based Motion Control
Authors: Nemati Alireza , Kumar Manish
Published: December 2014

In this paper, a nonlinear control of a tilting rotor quadcopter is presented. The overall control architecture is divided into two sub-controllers. The first controller is based on the feedback linearization control derived from the dynamic model of the tilting quadcopter. This controls the pitch, roll, and yaw motions required for movement along an arbitrary trajectory in space. The second controller is based on two PD controllers which are used to control the tilting of the quadcopter independently along the pitch and the yaw directions respectively. The overall control enables the quadcopter to combine tilting and movement along a desired trajectory simultaneously. Simulation studies are presented based on the developed nonlinear dynamic model of the tilting rotor quadcopter to demonstrate the validity and effectiveness of the overall control system for an arbitrary trajectory tracking.
Enhancing the platinum atomic layer deposition infiltration depth inside anodic alumina nanoporous membrane
Authors: Vaish Amit , Krueger Susan , Dimitriou Michael , Majkrzak Charles , Vanderah David J. , Chen Lei , Gawrisch Klaus
Published: December 2014

Nanoporous platinum membranes can be straightforwardly fabricated by forming a Pt coating inside the nanopores of anodic alumina membranes (AAO) using atomic layer deposition (ALD). However, the high-aspect-ratio of AAO makes Pt ALD very challenging. By tuning the process deposition temperature and precursor exposure time, enhanced infiltration depth along with conformal coating was achieved for Pt ALD inside the AAO templates. Cross-sectional scanning electron microscopy/energy dispersive x-ray spectroscopy and small angle neutron scattering were employed to analyze the Pt coverage and thickness inside the AAO nanopores. Additionally, one application of platinum-coated membrane was demonstrated by creating a high-density protein-functionalized interface.
Projecting regional change
Authors: Hall Alex
Published: December 2014

How accurate are regional projections of climate change derived from downscaling global climate model results?
The Global Fight Against Dementia
Authors: Joanette Yves , Hirsch Etienne C. , Goldman Michel
Published: December 2014

The G8 Summit on Dementia held in London a year ago has culminated in a year of global collaborative efforts to develop an action plan to address the looming challenge of dementia.
Utility of Real-Time PCR for Detection of Exserohilum rostratum in Body and Tissue Fluids during the Multistate Outbreak of Fungal Meningitis and Other Infections
Authors: Gade Lalitha , Grgurich Dale E. , Kerkering Thomas M. , Brandt Mary E. , Litvintseva Anastasia P.
Published: December 2014

Exserohilum rostratum
was the major cause of the multistate outbreak of fungal meningitis linked to contaminated injections of methylprednisolone acetate produced by the New England Compounding Center. Previously, we developed a fungal DNA extraction procedure and broad-range and
E. rostratum
-specific PCR assays and confirmed the presence of fungal DNA in 28% of the case patients. Here, we report the development and validation of a TaqMan real-time PCR assay for the detection of
E. rostratum
in body fluids, which we used to confirm infections in 57 additional case patients, bringing the total number of case patients with PCR results positive for
E. rostratum
to 171 (37% of the 461 case patients with available specimens). Compared to fungal culture and the previous PCR assays, this real-time PCR assay was more sensitive. Of the 139 identical specimens from case patients tested by all three methods, 19 (14%) were positive by culture, 41 (29%) were positive by the conventional PCR assay, and 65 (47%) were positive by the real-time PCR assay. We also compared the utility of the real-time PCR assay with that of the previously described beta-
d
-glucan (BDG) detection assay for monitoring response to treatment in case patients with serially collected CSF. Only the incident CSF specimens from most of the case patients were positive by real-time PCR, while most of the subsequently collected specimens were negative, confirming our previous observations that the BDG assay was more appropriate than the real-time PCR assay for monitoring the response to treatment. Our results also demonstrate that the real-time PCR assay is extremely susceptible to contamination and its results should be used only in conjunction with clinical and epidemiological data.
Sonication of Explanted Prosthesis Combined with Incubation in BD Bactec Bottles for Pathogen-Based Diagnosis of Prosthetic Joint Infection
Authors: Shen Hao , Tang Jin , Wang Qiaojie , Jiang Yao , Zhang Xianlong
Published: December 2014

Prosthetic joint infection (PJI) is a rare but refractory complication of arthroplasty. Accurate identification of pathogens is a key step for successful treatment of PJI, which remains a challenge for clinicians and laboratory workers. We designed a combined culture method with sonication of implants and incubation in a BD Bactec system to improve the effectiveness of pathogen diagnosis in PJI. The aims of this study were to investigate the diagnostic accuracy of sonicate fluid cultures in the BD Bactec system and to compare the results with those of synovial fluid cultures in the BD Bactec system. The prosthetic components removed were sonicated in Ringer's solution, and then sonicate fluid was incubated in Bactec bottles for 5 days. Synovial fluid was incubated in Bactec bottles for 5 days as a control. Synovial fluid cultures with Bactec bottles and sonicate fluid cultures with Bactec bottles showed sensitivities of 64% and 88%, respectively (
P
= 0.009), with specificities of 98% and 87% (
P
= 0.032), respectively. Sonicate fluid cultures with Bactec bottles were more sensitive than synovial fluid cultures with Bactec bottles regardless of whether antimicrobial agents were used within 14 days before surgery (81% versus 52%;
P
= 0.031) or not (93% versus 72%;
P
= 0.031). Sonication of explanted prostheses followed by incubation of the resulting sonicate fluid in Bactec bottles detected many more pathogens than did synovial fluid cultures with Bactec bottles. This method is also effective in cases with antibiotic treatment before surgery.
Clinical and Microbiological Characteristics of Eggerthella lenta Bacteremia
Authors: Gardiner B. J. , Tai A. Y. , Kotsanas D. , Francis M. J. , Roberts S. A. , Ballard S. A. , Junckerstorff R. K. , Korman T. M.
Published: December 2014

Eggerthella lenta
is an emerging pathogen that has been underrecognized due to historical difficulties with phenotypic identification. Until now, its pathogenicity, antimicrobial susceptibility profile, and optimal treatment have been poorly characterized. In this article, we report the largest cohort of patients with
E. lenta
bacteremia to date and describe in detail their clinical features, microbiologic characteristics, treatment, and outcomes. We identified 33 patients; the median age was 68 years, and there was no gender predominance. Twenty-seven patients (82%) had serious intra-abdominal pathology, often requiring a medical procedure. Of those who received antibiotics (28/33, 85%), the median duration of treatment was 21.5 days. Mortality from all causes was 6% at 7 days, 12% at 30 days, and 33% at 1 year. Of 26 isolates available for further testing, all were identified as
E. lenta
by both commercially available matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) systems, and none were found to harbor a
vanA
or
vanB
gene. Of 23 isolates which underwent susceptibility testing, all were susceptible to amoxicillin-clavulanate, cefoxitin, metronidazole, piperacillin-tazobactam, ertapenem, and meropenem, 91% were susceptible to clindamycin, 74% were susceptible to moxifloxacin, and 39% were susceptible to penicillin.
Rapid Homogeneous Immunoassay Based on Time-Resolved Förster Resonance Energy Transfer for Serodiagnosis of Acute Hantavirus Infection
Authors: Hepojoki Satu , Hepojoki Jussi , Hedman Klaus , Vapalahti Olli , Vaheri Antti
Published: December 2014

We recently introduced a homogeneous immunoassay based on time-resolved Förster resonance energy transfer (TR-FRET) elicited by fluorophore-labeled antigen and fluorophore-labeled protein L, bound by an immunoglobulin. As the first clinical application, we employ this approach (LFRET) in serodiagnosis of Puumala hantavirus (PUUV) infection. A reference panel containing serum from individuals with acute (
n =
21) or past (
n =
17) PUUV infection and from PUUV-seronegative individuals (
n =
20) was used to define the parameters. The clinical assay performance was evaluated with a prospectively collected serum panel (panel 2;
n =
153). Based on the results for panel 1, the threshold for positivity was set at a signal level that was 3-fold over background, while those with a signal <3-fold over the background level were considered PUUV seronegative. With panel 1, 20/21 acute- and 7/10 past-infection samples induced positive signals, compared to 0/20 seronegatives. With panel 2, a positive signal was obtained in 39/40 acute- and 4/10 past-infection samples, as opposed to 7/103 seronegatives. However, after IgG depletion, 58/61 acute-infection samples were LFRET positive, while all past-infection and seronegative samples were negative, corresponding to 100% specificity and 95% sensitivity in detection of acute PUUV infection. We demonstrate that the novel immunoassay is a promising tool for rapid serodiagnosis of acute Puumala virus infection.
Contribution of (1,3)-Beta-
d
-Glucan to Diagnosis of Invasive Candidiasis after Liver Transplantation
Authors: Levesque E. , El Anbassi S. , Sitterle E. , Foulet F. , Merle J. C. , Botterel F.
Published: December 2014

Invasive candidiasis (IC) causes high morbidity and mortality rates after liver transplantation, in part due to delayed diagnosis. The fungal cell wall component (1,3)-beta-
d
-glucan (BG) could be an early biomarker of IC. This preliminary prospective study was designed to evaluate the contribution of BG measurements to the diagnosis of IC after liver transplantation. All consecutive patients who underwent liver transplantation at Henri Mondor Hospital in France between January and June 2013 were enrolled prospectively in the study. They were monitored weekly for colonization by
Candida
, and colonization index values were calculated. Serum samples were tested for BG (Fungitell; Cape Cod Inc.) at least weekly between liver transplantation and discharge from the hospital. A total of 52 patients (including 39 male patients) were enrolled, with a median age of 55 years (range, 31 to 69 years). The median Model for End-Stage Liver Disease (MELD) score was 27 (range, 6 to 40). Cultures from 42 patients (81%) yielded
Candida
spp., with the most common
Candida
species isolated being
Candida glabrata
(47%). Six cases of documented IC were found for four of the 52 patients. On the day the clinical diagnosis of IC was made, analysis based on combining two sequential BG-positive samples (>146 pg/ml) and a colonization index of ≥0.5 revealed sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) results of 83%, 89%, 50%, and 97.6%, respectively. The detection of BG associated with
Candida
colonization may be a promising tool based on a high NPV that can rule out IC among high-risk patients.
Evaluation of the Cepheid Xpert C. difficile/
Epi
and Meridian Bioscience
illumi
gene C. difficile Assays for Detecting Clostridium difficile Ribotype 033 Strains
Authors: Androga Grace O. , McGovern Alan M. , Elliott Briony , Chang Barbara J. , Perkins Timothy T. , Foster Niki F. , Riley Thomas V.
Published: December 2014

Clostridium difficile
PCR ribotype 033 (RT033) is found in the gastrointestinal tracts of production animals and, occasionally, humans. The
illumi
gene
C. difficile
assay (Meridian Bioscience, Inc.) failed to detect any of 52
C. difficile
RT033 isolates, while all strains signaled positive for the binary toxin genes but were reported as negative for
C. difficile
by the Xpert
C. difficile
/
Epi
assay (Cepheid).
LMP1 Promotes Expression of Insulin-Like Growth Factor 1 (IGF1) To Selectively Activate IGF1 Receptor and Drive Cell Proliferation
Authors: Tworkoski Kathryn , Raab-Traub Nancy
Published: December 2014

Epstein-Barr Virus (EBV) is a gammaherpesvirus that infects the majority of the human population and is linked to the development of multiple cancers, including nasopharyngeal carcinoma. Latent membrane protein 1 (LMP1) is considered the primary oncoprotein of EBV, and in epithelial cells it induces the expression and activation, or phosphorylation, of the epidermal growth factor receptor kinase. To identify effects on additional kinases, an unbiased screen of receptor tyrosine kinases potentially activated by LMP1 was performed. Using a protein array, it was determined that LMP1 selectively activates insulin-like growth factor 1 receptor (IGF1R). This activation takes place in fibroblast, epithelial, and nasopharyngeal cell lines that express LMP1 stably and transiently. Of note, LMP1 altered the phosphorylation, but not the expression, of IGF1R. The use of LMP1 mutants with defective signaling domains revealed that the C-terminal activating region 2 domain of LMP1 increased the mRNA expression and the secretion of the ligand IGF1, which promoted phosphorylation of IGF1R. IGF1R phosphorylation was dependent upon activation of canonical NF-κB signaling and was suppressed by IκBα and a dominant negative form of TRAF6. Inhibition of IGF1R activation with two small-molecule inhibitors, AG1024 and picropodophyllin (PPP), or with short hairpin RNA (shRNA) directed against IGF1R selectively reduced proliferation, focus formation, and Akt activation in LMP1-positive cells but did not impair LMP1-induced cell migration. Expression of constitutively active Akt rescued cell proliferation in the presence of IGF1R inhibitors. These findings suggest that LMP1-mediated activation of IGF1R contributes to the ability of LMP1 to transform epithelial cells.

IMPORTANCE
EBV is linked to the development of multiple cancers in both lymphoid and epithelial cells, including nasopharyngeal carcinoma. Nasopharyngeal carcinoma is a major cancer that develops in specific populations, with nearly 80,000 new cases reported annually. LMP1 is consistently expressed in early lesions and continues to be detected within 50 to 80% of these cancers at later stages. It is therefore of paramount importance to understand the mechanisms through which LMP1 alters cell growth and contributes to tumorigenesis. This study is the first to determine that LMP1 activates the IGF1R tyrosine kinase by regulating expression of the ligand IGF1. Additionally, the data in this paper reveal that specific targeting of IGF1R selectively impacts LMP1-positive cells. These findings suggest that therapies directed against IGF1R may specifically impair the growth of EBV-infected cells.