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Sample records for guinea pig ventricular

  1. The relationship between contraction and intracellular sodium in rat and guinea-pig ventricular myocytes.

    PubMed Central

    Harrison, S M; McCall, E; Boyett, M R

    1992-01-01

    1. The contraction, measured optically, and the intracellular Na+ activity (aNai), measured with the Na(+)-sensitive fluorescent dye SBFI, have been recorded simultaneously in rat and guinea-pig ventricular myocytes. 2. In rat and guinea-pig ventricular myocytes at rest, aNai was 7.8 +/- 0.3 mM (n = 4) and 5.1 +/- 0.3 mM (n = 16), respectively. 3. When both rat and guinea-pig ventricular myocytes were stimulated at 1 Hz after a rest there was usually a gradual increase in twitch shortening (referred to as a 'staircase') over several minutes accompanied by an increase in aNai over a similar time course. Twitch shortening increased by 21 +/- 3% (n = 6) and 20 +/- 4% (n = 16) (of steady-state twitch shortening during 1 Hz stimulation) per millimolar rise in aNai in rat and guinea-pig ventricular myocytes, respectively. 4. When rat and guinea-pig ventricular myocytes were exposed to strophanthidin to block the Na(+)-K+ pump, there were increases in twitch shortening and aNai over similar time courses. Twitch shortening increased by 24 +/- 4% (n = 5) and 20 +/- 3% (n = 10) (of control twitch shortening) per millimolar rise in aNai in rat and guinea-pig ventricular myocytes respectively. 5. The inotropic effect of cardiac glycosides, such as strophanthidin, is widely regarded to be principally the result of the rise in aNai. The similarity of the relation between twitch shortening and aNai during the staircase and on application of strophanthidin suggests that the progressive increase in the strength of contraction during the staircase was also linked to the rise in aNai. 6. In guinea-pig, but not rat, ventricular myocytes there was hysteresis in the relation between twitch shortening and aNai on application and wash-off of strophanthidin. This indicates that strophanthidin has another inotropic action in guinea-pig ventricular myocytes. 7. A computer model of excitation-contraction coupling has been developed to simulate the staircase and the action of cardiac glycoside

  2. Muscarinic receptor stimulation and cyclic AMP-dependent effects in guinea-pig ventricular myocardium.

    PubMed Central

    Schmied, R.; Korth, M.

    1990-01-01

    1. The effect of carbachol on force of contraction, contraction duration, intracellular Na+ activity and cyclic AMP content was studied in papillary muscles of the guinea-pig exposed to isoprenaline or the phosphodiesterase inhibitor 3-isobutyl, 1-methyl xanthine (IBMX). The preparations were obtained from reserpine-pretreated animals and were electrically driven at a frequency of 0.2 Hz. 2. Isoprenaline (10 nM) and IBMX (100 microM) produced comparable positive inotropic effects of 9.8 and 9.7 mN, respectively. Carbachol (3 microM) attenuated the inotropic effects by 82% (isoprenaline) and by 79% (IBMX). The shortening of contraction duration which accompanied the positive inotropic effect of isoprenaline (by 14.9%) and of IBMX (by 22.4%) was not significantly affected by 3 microM carbachol. 3. The positive inotropic effect of 10 nM isoprenaline and of 100 microM IBMX was accompanied by an increase in cellular cyclic AMP content of 58 and 114%, respectively. Carbachol (3 microM) failed to reduce significantly the elevated cyclic AMP content of muscles exposed to either isoprenaline or IBMX. 4. In the quiescent papillary muscle, isoprenaline (10 nM) and IBMX (100 microM) reduced the intracellular Na+ activity by 28 and 17%, respectively. This decline was not influenced by the additional application of 3 microM carbachol. 5. The results demonstrate that muscarinic antagonism in guinea-pig ventricular myocardium exposed to cyclic AMP-elevating drugs is restricted to force of contraction. The underlying mechanism does not apparently involve the cytosolic signal molecule cyclic AMP. PMID:1691677

  3. Ultraviolet photoalteration of late Na+ current in guinea-pig ventricular myocytes.

    PubMed

    La, C; You, Y; Zhabyeyev, P; Pelzer, D J; McDonald, T F

    2006-03-01

    UV irradiation has multiple effects on mammalian cells, including modification of ion channel function. The present study was undertaken to investigate the response of membrane currents in guinea-pig ventricular myocytes to the type A (355, 380 nm) irradiation commonly used in Ca(2+) imaging studies. Myocytes configured for whole-cell voltage clamp were generally held at -80 mV, dialyzed with K(+)-, Na(+)-free pipette solution, and bathed with K(+)-free Tyrode's solution at 22 degrees C. During experiments that lasted for approximately 35 min, UVA irradiation caused a progressive increase in slowly-inactivating inward current elicited by 200-ms depolarizations from -80 to -40 mV, but had little effect on background current or on L-type Ca(2+) current. Trials with depolarized holding potential, Ca(2+) channel blockers, and tetrodotoxin (TTX) established that the current induced by irradiation was late (slowly-inactivating) Na(+) current (I(Na)). The amplitude of the late inward current sensitive to 100 microM: TTX was increased by 3.5-fold after 20-30 min of irradiation. UVA modulation of late I(Na) may (i) interfere with imaging studies, and (ii) provide a paradigm for investigation of intracellular factors likely to influence slow inactivation of cardiac I(Na). PMID:16783617

  4. Inactivation of the cardiac Na+ channels in guinea-pig ventricular cells through the open state.

    PubMed Central

    Mitsuiye, T; Noma, A

    1995-01-01

    1. The inactivation kinetics of the Na+ current were investigated using the improved oil-gap voltage clamp method in single ventricular cells of guinea-pig hearts. 2. Activation of the Na+ current was observed on depolarization more positive than -50 mV from a holding potential of -100 mV, and inactivation was complete during these depolarizations. The time course of current decay was fitted by a double exponential at potentials between -40 and -15 mV, and virtually by a single exponential at more positive potentials. The decay time courses examined either by the double-pulse protocol or the single-pulse protocol were similar. 3. The double-pulse protocol clearly revealed a sigmoidal onset of inactivation on depolarization. The initial delay of inactivation decreased with more positive potentials. The time course of double-pulse inactivation was reconstructed by integrating the Na+ current recorded by a continuous depolarization. 4. These findings are consistent with the hypothesis that the cardiac Na+ channel inactivates exclusively through the open state. PMID:7562602

  5. Clobutinol delays ventricular repolarization in the guinea pig heart: comparison with cardiac effects of HERG K+ channel inhibitor E-4031.

    PubMed

    Takahara, Akira; Sasaki, Rieko; Nakamura, Mariko; Sendo, Akiko; Sakurai, Yukiko; Namekata, Iyuki; Tanaka, Hikaru

    2009-12-01

    Clobutinol has been clinically reported to induce long QT syndrome. To clarify its cardiac electrophysiological properties, we compared effects of clobutinol on the isolated myocardium and anesthetized guinea pig heart with those of a hERG K channel blocker, E-4031. In isolated guinea pig ventricular tissues, clobutinol (3 microM) as well as E-4031 (10-100 nM) prolonged the action potential duration without affecting maximum upstroke velocity, but no further prolongation was observed after application of 30 microM clobutinol. In anesthetized closed-chest guinea pigs, clobutinol (1 and 10 mg/kg, intravenously) and E-4031 (0.01 and 1 mg/kg, intravenously) prolonged the QT interval and duration of the monophasic action potential (MAP) in a dose-dependent manner and at the same time increased the beat-to-beat variability of the MAP duration and reversed use-dependent prolongation of the MAP duration and triangulation of the MAP configuration. These results suggest that clobutinol delayed the ventricular repolarization and increased the proarrhythmic parameters linked to the hERG K channel inhibitor-induced torsade de pointes arrhythmias. PMID:19770670

  6. Caffeine-induced immobilization of gating charges in isolated guinea-pig ventricular heart cells

    PubMed Central

    Leroy, Jérôme; Lignon, Jacques M; Gannier, François; Argibay, Jorge A; Malécot, Claire O

    2002-01-01

    The effects of 10 mM caffeine (CAF) on intramembrane charge movements (ICM) were studied in isolated guinea-pig ventricular heart cells with the whole-cell patch-clamp technique.In the presence of CAF, the properties (voltage dependence, maximum QON [Qmax], availability with voltage) of QON charge activated from −110 mV were barely affected. Following a 100 ms prepulse to −50 mV to decrease the participation of charges originating from Na channels, the voltage dependence of QON was shifted by 5 mV (negative component) and by 10 mV (positive component) towards negative potentials, and Qmax was depressed by 16.5%.CAF drastically reduced in a time- and voltage-dependent manner QOFF on repolarization to −50 mV, the effects being greater at positive potentials.CAF-induced QOFF immobilization could be almost entirely removed by repolarization to voltages as negative as −170 mV. In these conditions, the voltage-dependence of QOFF (repolarization to +30 to −170 mV) was shifted by 17 mV (negative component) and 30 mV (positive component) towards negative potentials, suggesting an interconversion into charge 2.Most of CAF effects were suppressed when the sarcoplasmic reticulum (SR) was not functional or when the cells were loaded with BAPTA-AM.We conclude that CAF effects on ICM are likely due to Ca2+ ions released from the SR, and which accumulate in the subsarcolemmal fuzzy spaces in the vicinity of the Ca channels. Because CAF effects were more pronounced on QOFF than on QON the channels have likely to open before Ca2+ ions could affect their gating properties. It is speculated that such an effect on gating charges might contribute to the Ca-induced inactivation of the Ca current. PMID:11834620

  7. Effects of trimebutine maleate on delayed rectifier K+ currents in guinea-pig ventricular myocytes.

    PubMed

    Morisawa, T; Hasegawa, J; Tanabe, K; Watanabe, A; Kitano, M; Kishimoto, Y

    2000-04-01

    The effects of trimebutine maleate, a drug commonly used to regulate motility in the gastrointestinal tract, on the delayed rectifier K+ current (I(K)) were evaluated in guinea-pig ventricular myocytes to determine whether the drug has a proarrhythmic effect through blockade of I(K). Trimebutine decreased I(K) in a concentration-dependent manner. To investigate the effects of trimebutine on two components of I(K) (I(Kr) and I(Ks); rapidly activated and slowly activated components, respectively), we performed the envelope-of-tails test. Trimebutine-sensitive I(K) was determined by digital subtraction of I(K) during exposure to trimebutine from control I(K) for each duration of the test pulse over the range 50 ms-2 s. The ratio of deltaI(K,tail)/deltaI(K) plotted against pulse duration for trimebutine-sensitive I(K) gradually decreased to a steady-state value as the duration of the test pulse was lengthened. This finding suggested a weak inhibitory effect of trimebutine on both I(Kr) and I(Ks). The effects of trimebutine on the inward rectifier K+ current (I(K1)) responsible for the resting potential and final repolarization phase of the action potential were investigated by applying voltage clamp ramps over a broad range of potentials. No significant effects were observed at 10 or 100 microM. We next investigated the effects of the drug on the L-type Ca2+ current (I(Ca)). Significant inhibition of I(Ca) was observed at trimebutine concentrations greater than 10 microM. These results suggested that trimebutine maleate has weak inhibitory effects on I(Kr), I(Ks) and I(Ca) at concentrations much higher than those in clinical use. PMID:10813550

  8. Intracellular Ca2+ transients during rapid cooling contractures in guinea-pig ventricular myocytes.

    PubMed Central

    Bers, D M; Bridge, J H; Spitzer, K W

    1989-01-01

    1. We measured intracellular Ca2+ transients during rapid cooling contractures (RCCs) in guinea-pig ventricular myocytes using the fluorescent Ca2+ indicator, Indo-1. 2. Rapid cooling of myocytes from 22 to 0-1 degrees C induced a rapid increase in [Ca2+]i which preceded the peak of the contraction and was sometimes large enough to saturate Indo-1. This indicates that [Ca2+]i may reach greater than 10 microM during an RCC. 3. The [Ca2+]i during the RCC slowly declined from its peak value and most of this decline in [Ca2+]i can be attributed to slow reaccumulation of Ca2+ by the sarcoplasmic reticulum (SR) in the cold. RCCs induced in the absence of Cao2+, were not different from control, supporting previous conclusions that RCCs depend exclusively on intracellular Ca2+ stores. 4. RCCs are depressed by long rest periods (rest decay) or by exposure to ryanodine or caffeine, which supports conclusions that RCCs are due to Ca2+ release from the SR. The rest decay of RCCs can be almost completely prevented by applying Nao(+)-free solution during the rest period. This implies that the loss of SR Ca2+ during rest depends on the sarcolemmal Na(+)-Ca2+ exchange (and not the sarcolemmal Ca2(+)-ATPase pump). 5. Rapid rewarming during an RCC normally leads to an additional transient contraction (or rewarming spike), without any increase in [Ca2+]i. Thus, the rewarming spike might be attributable to an increase in myofilament Ca2+ sensitivity induced by rewarming. 6. A second RCC is used to assess the fraction of Ca2+ which is re-sequestered by the SR during relaxation from the first RCC. In control solution progressive RCCs decline in amplitude, but in Na(+)-free, Ca2(+)-free solution they are of constant amplitude. We conclude that the SR Ca2+ pump and Na(+)-Ca2+ exchange are responsible for relaxation and that the latter may account for 20-50% of relaxation. 7. These results support the use of RCCs as a useful means of assessing SR Ca2+ content in intact cardiac muscle cells

  9. Sodium-calcium exchange during the action potential in guinea-pig ventricular cells.

    PubMed Central

    Egan, T M; Noble, D; Noble, S J; Powell, T; Spindler, A J; Twist, V W

    1989-01-01

    1. Slow inward tail currents attributable to electrogenic sodium-calcium exchange can be recorded by imposing hyperpolarizing voltage clamp pulses during the normal action potential of isolated guinea-pig ventricular cells. The hyperpolarizations return the membrane to the resting potential (between -65 and -88 m V) allowing an inward current to be recorded. This current usually has peak amplitude when repolarization is imposed during the first 50 ms after the action potential upstroke, but becomes negligible once the final phase of repolarization is reached. The envelope of peak current tail amplitudes strongly resembles that of the intracellular calcium transient recorded in other studies. 2. Repetitive stimulation producing normal action potentials at a frequency of 2 Hz progressively augments the tail current recorded immediately after the stimulus train. Conversely, if each action potential is prematurely terminated at 0.1 Hz, repetitive stimulation produces a tail current much smaller than the control value. The control amplitude of inward current is only maintained if interrupted action potentials are separated by at least one full 'repriming' action potential. These effects mimic those on cell contraction (Arlock & Wohlfart, 1986) and suggest that progressive changes in tail current are controlled by variations in the amplitude and time course of the intracellular calcium transient. 3. When intracellular calcium is buffered sufficiently to abolish contraction, the tail current is abolished. Substitution of calcium with strontium greatly reduces the tail current. 4. The inward tail current can also be recorded at more positive membrane potentials using standard voltage clamp pulse protocols. In this way it was found that temperature has a large effect on the tail current, which can change from net inward at 22 degrees C to net outward at 37 degrees C. The largest inward currents are usually recorded at about 30 degrees C. It is shown that this effect is

  10. Phorbol ester activation of chloride current in guinea-pig ventricular myocytes.

    PubMed Central

    Shuba, L. M.; Asai, T.; McDonald, T. F.

    1996-01-01

    1. Although earlier studies with phorbol esters indicate that protein kinase C (PKC) may be an important regulator of Cl- current (Icl) in cardiac cells, there is a need for additional quantitative data and investigation of conflicting findings. Our objectives were to measure the magnitude, time course, and concentration-dependence of Icl activated in guinea-pig ventricular myocytes by phorbol 12-myristate 13-acetate (PMA), evaluate its PKC dependence, and examine its modification by external and internal ions. 2. The whole-cell patch clamp technique was used to apply short depolarizing and hyperpolarizing pulses to myocytes superfused with Na(+)-, K(+)-, Ca(2+)-free solution (36 degrees C) and dialysed with Cs+ solution. Stimulation of membrane currents by PMA (threshold < or = 1nM, EC50 approximately equal to 14 nM, maximal 40% increase with > or = 100 nM) plateaued within 6-10 min. 3. PMA-activated current was time-independent, and suppressed by l mM 9-anthracenecarboxylic acid (9-AC). Its reversal potential (Erev) was sensitive to changes in the Cl- gradient, and outward rectification of the current-voltage (I-V) relationship was more pronounced with 30 mM than 140 mM Cl- dialysate. 4. The relative permeability of PMA-activated channels estimated from Erev measurements was I- > Cl- > > aspartate. Channel activation was independent of external Na+. 5. PMA failed to activate Icl in myocytes pretreated with 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) or dialysed with pCa 10.5 solution. Lack of response to 4 alpha-phorbol 12, 13-didecanoate (alpha PDD) was a further indication of mediation by PKC. 6. Icl induced by 2 microM forskolin was far larger than that induced by PMA, suggesting that endogenous protein kinase A is a much stronger Cl- channel activator than endogenous PKC in these myocytes. 7. The macroscopic properties of PMA-induced Icl appear to be indistinguishable from those of PKA-activated Icl. We discount stimulation of PKA by PMA as an

  11. Effects of nicorandil on the cAMP-dependent Cl- current in guinea-pig ventricular cells.

    PubMed

    Nishimura, Nami; Reien, Yoshie; Matsumoto, Akio; Ogura, Takehiko; Miyata, Yuuichi; Suzuki, Kazumasa; Nakazato, Yuji; Daida, Hiroyuki; Nakaya, Haruaki

    2010-01-01

    In guinea-pig cardiomyocytes, a cAMP-dependent Cl(-) current (I(Cl,cAMP)) flows through a cardiac isoform of the cystic fibrosis transmembrane conductance regulator (CFTR), which belongs to a family of the ATP-binding cassette (ABC) proteins. Although several K(+)-channel openers and sulfonylurea ATP-sensitive K(+) (K(ATP))-channel blockers reportedly inhibit I(Cl,cAMP), effects of nicorandil on the Cl(-) current have not been evaluated. This study was conducted to examine the effects of nicorandil on I(Cl,cAMP) in isolated guinea-pig ventricular cells using patch clamp techniques. Nicorandil in concentrations higher than 300 microM enhanced the I(Cl,cAMP) preactivated by 0.1 microM isoproterenol. The isoproterenol-induced I(Cl,cAMP) was inhibited by 100 microM glibenclamide, but not by 100 microM pinacidil. SNAP (S-nitroso-N-acetyl-D,L-penicillamine, 10 microM), a nitric oxide (NO) donor, similarly enhanced the isoproterenol-induced I(Cl,cAMP). However, SG-86, a denitrated metabolite possessing K(+ )channel-opening action, failed to enhance the Cl(-) current. When the I(Cl,cAMP) was activated by 3-isobutyl-1-methylxanthine (IBMX, 30 microM), either nicorandil or SNAP failed to enhance the isoproterenol-induced I(Cl,cAMP). Thus, nicorandil enhances I(Cl,cAMP) in guinea-pig cardiomyocytes through an increase in intracellular cGMP, although direct modulation of I(Cl,cAMP) by NO cannot be completely excluded. PMID:20308804

  12. Effects of the antitussive drug cloperastine on ventricular repolarization in halothane-anesthetized guinea pigs.

    PubMed

    Takahara, Akira; Fujiwara, Kaori; Ohtsuki, Atsushi; Oka, Takayuki; Namekata, Iyuki; Tanaka, Hikaru

    2012-01-01

    Cloperastine is an antitussive drug, which can be received as an over-the-counter cold medicine. The chemical structure of cloperastine is quite similar to that of the antihistamine drug diphenhydramine, which is reported to inhibit hERG K⁺ channels and clinically induce long QT syndrome after overdose. To analyze its proarrhythmic potential, we compared effects of cloperastine and diphenhydramine on the hERG K⁺ channels expressed in HEK293 cells. We further assessed their effects on the halothane-anesthetized guinea-pig heart under the monitoring of monophasic action potential (MAP) of the ventricle. Cloperastine inhibited the hERG K⁺ currents in a concentration-dependent manner with an IC₅₀ value of 0.027 μM, whose potency was 100 times greater than that of diphenhydramine (IC₅₀; 2.7 μM). In the anesthetized guinea pigs, cloperastine at a therapeutic dose of 1 mg/kg prolonged the QT interval and MAP duration without affecting PR interval or QRS width. Diphenhydramine at a therapeutic dose of 10 mg/kg prolonged the QT interval and MAP duration together with increase in PR interval and QRS width. The present results suggest that cloperastine may be categorized as a QT-prolonging drug that possibly induces arrhythmia at overdoses like diphenhydramine does. PMID:23047467

  13. Identification of sodium-calcium exchange current in single ventricular cells of guinea-pig.

    PubMed Central

    Kimura, J; Miyamae, S; Noma, A

    1987-01-01

    1. The Na-Ca exchange current was investigated in single ventricular cells from guinea-pig hearts by combining the techniques of whole-cell voltage clamp and intracellular perfusion. 2. The membrane conductance was minimized by blocking Ca and K channels as well as the Na-K pump. Under these conditions, when Ca2+ was loaded internally by a pipette solution containing 430 nM-Ca2+, changing the Li+-rich external solution to a Na+-rich one induced a significant inward current. Applying external Na+ in the absence of internal Ca2+ did not appreciably change the current. 3. In contrast, perfusing 1 mM-external Ca2+ in the presence of internal Na+ which was loaded by a 20 mM-Na+ pipette solution, induced a marked outward current. Ca2+ superfusion in the absence of internal Na+ caused only a small current change. 4. The current-voltage relation of external-Ca2+- and external-Na+-induced current showed almost exponential voltage dependence as given by the equation i = a exp (rEF/RT), where a is a scaling factor that determines the magnitude of the current and r is a partition parameter used in the rate theory and represents the position of the energy barrier in the electrical field, which indicates the steepness of the voltage dependence of the current. E, F, R and T have their usual meanings. The value of a was 1-2 microA/microF and r about 0.35 for the Ca2+-induced outward current. At very positive or negative potentials, the current magnitude became smaller than expected from an exponential relation. 5. The current was blocked by heavy metal cations, such as La3+, Cd2+, Mn2+ and Ni2+ and partially blocked by amiloride and D600. 6. The temperature coefficient (Q10) value of the Ca2+-induced outward current was 3.6 +/- 0.4 (n = 4) at 0 mV and 4.0 +/- 0.9 at 50 mV in the range between 21 and 36 degrees C. 7. The outward current magnitude showed a sigmoidal dependence upon the external Ca2+ concentration with a half-maximum concentration, K1/2 of 1.38 mM and a Hill

  14. Effect of temperature on isoprenaline- and barium-induced slow action potentials in guinea-pig ventricular strips.

    PubMed

    Manzini, S; Parlani, M; Martucci, E; Maggi, C A; Meli, A

    1986-01-01

    The effect of variation in temperature (37-32 and 27 degrees C) on electrical and mechanical activity of depolarized and isoprenaline- or barium-reactivated guinea pig ventricular strips was studied. Lowering the temperature brings a marked prolongation of isoprenaline-induced slow action potentials. In addition the maximal rate of depolarization was strongly reduced at lower temperatures. These effects were observed at an extracellular Ca2+ concentration of either 0.9 or 2.5 mM. The accompanying mechanical activities was significantly increased by reduction in temperature. Barium-induced slow action potentials were similarly affected by temperature variations. These observations suggest that hypothermia exert a sort of calcium antagonistic action probably coupled to a reduction of repolarizing outward potassium currents. PMID:2430855

  15. Functional diversity of electrogenic Na+–HCO3− cotransport in ventricular myocytes from rat, rabbit and guinea pig

    PubMed Central

    Yamamoto, Taku; Swietach, Pawel; Rossini, Alessandra; Loh, Shih-Hurng; Vaughan-Jones, Richard D; Spitzer, Kenneth W

    2005-01-01

    The Na+–HCO3− cotransporter (NBC) is an important sarcolemmal acid extruder in cardiac muscle. The characteristics of NBC expressed functionally in heart are controversial, with reports suggesting electroneutral (NBCn; 1HCO3− : 1Na+; coupling coefficient n = 1) or electrogenic forms of the transporter (NBCe; equivalent to 2HCO3− : 1Na+; n = 2). We have used voltage-clamp and epifluorescence techniques to compare NBC activity in isolated ventricular myocytes from rabbit, rat and guinea pig. Depolarization (by voltage clamp or hyperkalaemia) reversibly increased steady-state pHi while hyperpolarization decreased it, effects seen only in CO2/HCO3−-buffered solutions, and blocked by S0859 (cardiac NBC inhibitor). Species differences in amplitude of these pHi changes were rat > guinea pig ≈ rabbit. Tonic depolarization (−140 mV to −0 mV) accelerated NBC-mediated pHi recovery from an intracellular acid load. At 0 mV, NBC-mediated outward current at resting pHi was +0.52 ± 0.05 pA pF−1 (rat, n = 5), +0.26 ± 0.05 pA pF−1 (guinea pig, n = 5) and +0.10 ± 0.03 pA pF−1 (rabbit, n = 9), with reversal potentials near −100 mV, consistent with n = 2. The above results indicate a functionally active voltage-sensitive NBCe in these species. Voltage-clamp hyperpolarization negative to the reversal potential for NBCe failed, however, to terminate or reverse NBC-mediated pHi-recovery from an acid load although it was slowed significantly, suggesting electroneutral NBC may also be operational. NBC-mediated pHi recovery was associated with a rise of [Na+]i at a rate ∼25% of that mediated via NHE, and consistent with an apparent NBC stoichiometry between n = 1 and n = 2. In conclusion, NBCe in the ventricular myocyte displays considerable functional variation among the three species tested (greatest in rat, least in rabbit) and may coexist with some NBCn activity. PMID:15550467

  16. alpha-Adrenergic inhibition of the beta-adrenoceptor-dependent chloride current in guinea-pig ventricular myocytes.

    PubMed Central

    Iyadomi, I; Hirahara, K; Ehara, T

    1995-01-01

    1. alpha 1-Adrenoceptor-mediated inhibition of the beta-adrenoceptor-dependent Cl- current was investigated in guinea-pig ventricular myocytes using the patch clamp technique. The Cl- conductance activated by noradrenaline (0.1-10 microM) with an alpha 1-blocker (prazosin, 5 microM) was significantly greater than that activated by noradrenaline alone. Phenylephrine and methoxamine, alpha 1-agonists, exerted an inhibitory effect on the Cl- conductance activated by isoprenaline. The dose-response relationship for isoprenaline and the Cl- current activation was shifted to higher doses in the presence of phenylephrine (30 microM). 2. The interaction of alpha 1- and beta-agonists on Cl- current was also observed on the single channel level; in some of the outside-out membrane patches, phenylephrine (50 microM) depressed the activity of the single Cl- channel which was induced by 5 microM adrenaline. 3. Phenylephrine had no effect on the Cl- conductance induced by forskolin (0.5-5 microM), an activator of adenylate cyclase. The Cl- conductance activated persistently by isoprenaline in GTP gamma S-loaded cells was also insensitive to phenylephrine. The results suggest that the observed alpha 1-adrenergic attenuation of the beta-adrenergic response is not primarily due to inhibition of adenylate cyclase activity. The alpha 1-adrenergic action may interfere with the processes leading to enzyme activation in the beta-adrenergic pathway. PMID:8583419

  17. A new class III antiarrhythmic drug, MS-551, blocks the inward rectifier potassium channel in isolated guinea pig ventricular myocytes.

    PubMed

    Sato, R; Koumi, S; Hisatome, I; Takai, H; Aida, Y; Oyaizu, M; Karasaki, S; Mashiba, H; Katori, R

    1995-07-01

    We have studied the effects of MS-551 on the inward rectifier potassium channel (IK1) in isolated guinea-pig ventricular myocytes by use of whole-cell and single-channel recording techniques. MS-551 (5 microM) blocked the IK1 current. The percent blockade of the peak and steady-state IK1 current by MS-551 was constant at each test potential. In contrast 50 microM MS-551 failed to block either the sodium or the calcium current. Under cell-attached patch conditions, MS-551 reduced the open probability of IK1 channel activity by prolonging the interburst interval without changing either the unitary amplitude or the equilibrium potential. The blockade of IK1 was concentration-dependent. MS-551 did not change either the mean open time or mean closed time within a burst. Extracellular acidification (pH 6.4) strongly attenuated the effect of MS-551 on the open probability of IK1 channel activity when compared with its effect at pH 7.4. In summary, our results demonstrated that MS-551 blocked the IK1 channel. The neutral form of this drug molecules may penetrate the cardiac cell membrane via a hydrophobic pathway to block the steady-state IK1 current by reduction of open probability. PMID:7616432

  18. Inhibitory Effects of Glycyrrhetinic Acid on the Delayed Rectifier Potassium Current in Guinea Pig Ventricular Myocytes and HERG Channel

    PubMed Central

    Wu, Delin; Jiang, Linqing; Wu, Hongjin; Wang, Shengqi; Zheng, Sidao; Yang, Jiyuan; Liu, Yuna; Ren, Jianxun; Chen, Xianbing

    2013-01-01

    Background. Licorice has long been used to treat many ailments including cardiovascular disorders in China. Recent studies have shown that the cardiac actions of licorice can be attributed to its active component, glycyrrhetinic acid (GA). However, the mechanism of action remains poorly understood. Aim. The effects of GA on the delayed rectifier potassium current (IK), the rapidly activating (IKr) and slowly activating (IKs) components of IK, and the HERG K+ channel expressed in HEK-293 cells were investigated. Materials and Methods. Single ventricular myocytes were isolated from guinea pig myocardium using enzymolysis. The wild type HERG gene was stably expressed in HEK293 cells. Whole-cell patch clamping was used to record IK (IKr, IKs) and the HERG K+ current. Results. GA (1, 5, and 10 μM) inhibited IK (IKr, IKs) and the HERG K+ current in a concentration-dependent manner. Conclusion. GA significantly inhibited the potassium currents in a dose- and voltage-dependent manner, suggesting that it exerts its antiarrhythmic action through the prolongation of APD and ERP owing to the inhibition of IK (IKr, IKs) and HERG K+ channel. PMID:24069049

  19. A novel, voltage-dependent nonselective cation current activated by insulin in guinea pig isolated ventricular myocytes.

    PubMed

    Zhang, Yin Hua; Hancox, Jules C

    2003-04-18

    Insulin regulates cardiac metabolism and function by targeting metabolic proteins or voltage-gated ion channels. This study provides evidence for a novel, voltage-dependent, nonselective cation channel (NSCC) in the heart. Under voltage clamp at 37 degrees C and with major known conductances blocked, insulin (1 nmol/L to 1 micromol/L) activated an outwardly rectifying current (Iinsulin) in guinea pig ventricular myocytes. Iinsulin could be carried by Cs+, K+, Li+, and Na+ ions but not by NMDG+. It was inhibited by the NSCC blockers gadolinium and SKF96365 but not flufenamic acid. Iinsulin was largely blocked by the insulin receptor tyrosine kinase inhibitor HNMPA-(AM)3 and by the phospholipase C inhibitor U73122 but not by its inactive analogue U73433. Staurosporine, a potent blocker of protein kinase C, did not prevent the activation of Iinsulin. Application of an analogue of diacylglycerol, 1-oleoyl-2-acetyl-sn-glycerol, mimicked the effect of insulin. This activated an outwardly rectifying NSCC that could be carried by Cs+, K+, Li+, or Na+ and that was blocked by gadolinium but not by flufenamic acid or staurosporine. We conclude that the intracellular pathway leading to activation of this novel cardiac NSCC involves phospholipase C, is protein kinase C-independent, and may depend on direct channel activation by diacylglycerol. PMID:12637365

  20. The effect of oxygen free radicals on calcium current and dihydropyridine binding sites in guinea-pig ventricular myocytes.

    PubMed Central

    Guerra, L.; Cerbai, E.; Gessi, S.; Borea, P. A.; Mugelli, A.

    1996-01-01

    1. We used electrophysiological and binding techniques to determine the effects of oxygen free radicals (OFRs) generated by dihydroxyfumaric acid (DHF, 5 mM) on calcium current and dihydropyridine binding sites in guinea-pig isolated ventricular myocytes. 2. Binding of [3H]-PN200-110 to isolated ventricular myocytes revealed one population of binding sites with a KD of 0.11 +/- 0.01 nM and Bmax of 139.1 +/- 6.9 fmol mg-1 protein (n = 24). After 15 min of exposure to DHF, the density, but not the affinity of [3H]-PN200-110 binding sites was significantly (P < 0.01) reduced to 35% of the control value (Bmax = 49.4 +/- 3.7 fmol mg-1 protein, KD = 0.11 +/- 0.01 nM, n = 15). In the presence of superoxide dismutase (SOD) and catalase (CAT) the reduction in [3H]-PN200-110 binding sites was almost completely prevented (Bmax = 120.5 +/- 7.4 in control, n = 4 and 98.8 +/- 7.4 fmol mg-1 protein in DHF plus SOD and CAT, n = 4). KD values were not modified (0.08 +/- 0.01 in control and 0.09 +/- 0.01 nM in DHF plus SOD and CAT). 3. The time-course of the reduction of [3H]-PN200-110 binding sites by OFRs was paralleled by the decrease in L-type calcium current (Ica,L) measured in patch-clamped guinea-pig ventricular myocytes either in the absence or in the presence of EGTA in the patch pipette. In the former conditions OFRs induced the appearance of calcium-dependent alterations, i.e. the transient inward current, within 10 min. After 30 min of incubation with DHF, [3H]-PN200-110 binding sites were reduced to 25% of the control value. 4. In myocytes incubated with the antilipoperoxidant agent, butylated hydroxytoluene (BHT, 50 microM), the decrease in [3H]-PN200-110 binding sites caused by DHF was partially prevented (Bmax values after 30 min exposure to DHF were 55.5 +/- 1.9 and 23.7 +/- 5.9 fmol mg-1 protein in the presence and in the absence of BHT respectively, P < 0.05). BHT did not affect the decrease in [3H]-PN200-110 binding sites during the first 15 min of exposure to

  1. Effects of acidosis and NO on nicorandil-activated KATP channels in guinea-pig ventricular myocytes

    PubMed Central

    Moncada, Gustavo A; Kishi, Yukio; Numano, Fujio; Hiraoka, Masayasu; Sawanobori, Tohru

    2000-01-01

    Nicorandil is a hybrid compound of K+ channel opener and nitrate. We investigated a possible interaction of acidosis and nitric oxide (NO)-donors on the nicorandil-activated ATP-sensitive K+ channel (KATP) in guinea-pig ventricular myocytes using the patch-clamp technique.In whole-cell recordings, external application of 300 μM nicorandil activated KATP in the presence of 2 mM intracellular ATP concentration ([ATP]i) at external pH (pHo) 7.4, but the activated current was decreased by reducing pHo to 6.5–6.0.Single-channel recordings of inside-out patches revealed decreased open-state probability (Po) of KATP activated by nicorandil with reducing internal pH (pHi) from 7.2 to 6.0, whilst the channel activity increased at low pHi in the absence of nicorandil.Application of NO donors, 1 mM-sodium nitroprusside (SNP) or -NOR-3 to the membrane cytoplasmic side at pHi 7.2 increased the channel activity but decreased it at pHi 6.5–6.0. Neither removal of the drugs nor application of NO-scavengers reversed depression of channel activity induced by NO-donors.We conclude that an increase in pHo and pHi depresses rather than stimulates the nicorandil-activated KATP. Since NO-donors at low pHi exhibited a similar trend, involvement of H+ and NO interaction can be considered as a mechanism of decreased KATP activated by nicorandil. PMID:11082116

  2. Voltage-dependent decrease in the availability of single calcium channels by nitrendipine in guinea-pig ventricular cells.

    PubMed Central

    Kawashima, Y; Ochi, R

    1988-01-01

    1. The mechanism of Ca2+ channel block by nitrendipine was studied by recording single-channel activity from cell-attached patches on guinea-pig ventricular cells using patch pipettes containing 50 mM-Ba2+. Test depolarization pulses to around 10 mV with a duration of 100 ms were applied repetitively at 2 Hz. 2. The percentage of non-blank sweeps was maximal (about 40%) at a holding potential between -65 and -130 mV and decreased sigmoidally with its depolarization. Nitrendipine shifted the availability-voltage relationship in a hyperpolarizing direction. 3. From the number of consecutive non-blank sweeps and that of blank sweeps, the duration of the available state and that of the unavailable state were estimated. 4. The histogram of the duration of the available state showed a single-exponential distribution. Its mean duration was about 1.5 s and was shortened by nitrendipine. Correspondingly, the decay of the mean current during the depolarization step was accelerated by nitrendipine. 5. In the presence of 100 nM-nitrendipine the histogram of the duration of the unavailable state at large negative holding potentials was simulated as the sum of two exponential components, one with a time constant similar to that in the control and the other with a time constant of 6-7 s. 6. The histogram of the duration of the unavailable state at depolarized holding potentials was simulated by a double-exponential curve also in the control. The duration of the slow component was prolonged by nitrendipine. 7. The prolongation of the unavailable states initiated by drug binding during depolarization steps and maintained during depolarized holding potentials is the mechanism of the blockade. The rate constants of the state transitions between an available state and two unavailable states were estimated. PMID:2853222

  3. A novel antagonist, No. 7943, of the Na+/Ca2+ exchange current in guinea-pig cardiac ventricular cells.

    PubMed Central

    Watano, T.; Kimura, J.; Morita, T.; Nakanishi, H.

    1996-01-01

    1. The effects of No. 7943 on the Na+/Ca2+ exchange current and on other membrane currents were investigated in single cardiac ventricular cells of guinea-pig with the whole-cell voltage-clamp technique. 2. No. 7943 at 0.1-10 microM suppressed the outward Na+/Ca2+ exchange current in a concentration-dependent manner. The suppression was reversible and the IC50 value was approximately 0.32 microM. 3. No. 7943 at 5-50 microM suppressed also the inward Na+/Ca2+ exchange current in a concentration-dependent manner but with a higher IC50 value of approximately 17 microM. 4. In a concentration-response curve, No. 7943 raised the K(m)Ca2+ value, but did not affect the Imax value, indicating that No. 7943 is a competitive antagonist with external Ca2+ for the outward Na+/ Ca2+ exchange current. 5. The voltage-gated Na+ current, Ca2+ current and the inward rectifier K+ current were also inhibited by No. 7943 with IC50S of approximately 14, 8 and 7 microM, respectively. 6. In contrast to No. 7943, 3', 4'-dichlorobenzamil (DCB) at 3-30 microM suppressed the inward Na+/Ca2+ exchange current with IC50 of 17 microM, but did not affect the outward exchange current at these concentrations. 7. We conclude that No. 7943 inhibits the outward Na+/Ca2+ exchange current more potently than any other currents as a competitive inhibitor with external Ca2+. This effect is in contrast to DCB which preferentially inhibits the inward rather than the outward Na+/Ca2+ exchange current. PMID:8894178

  4. Cardiotoxicity of emetine dihydrochloride by calcium channel blockade in isolated preparations and ventricular myocytes of guinea-pig hearts.

    PubMed Central

    Lemmens-Gruber, R.; Karkhaneh, A.; Studenik, C.; Heistracher, P.

    1996-01-01

    1. The cardiotoxic effects of emetine dihydrochloride on mechanical and electrical activity were studied in isolated preparations (papillary muscles, sinoatrial and atrioventricular nodes, ventricular myocytes) of the guinea-pig heart. 2. Force of contraction was measured isometrically, action potentials and maximum rate of rise of the action potential were recorded by means of the intracellular microelectrode technique. Single channel L-type calcium current (Ba2+ ions as charge carrier) was studied with the patch-clamp technique in the cell-attached mode. 3. Emetine dihydrochloride (8-256 microM) reduced force of contraction in papillary muscles and spontaneous activity of sinoatrial and atrioventricular nodes concentration-dependently; the negative inotropic effect was abolished when the extracellular Ca2+ concentration was increased. 4. Maximum diastolic potential, action potential amplitude, maximum rate of rise of the action potential and the slope of the slow diastolic depolarization were decreased by emetine in sinoatrial as well as atrioventricular noes, while action potential duration was prolonged in both preparations (1-64 microM). 5. The amplitude of the L-type calcium single channel current was not altered by emetine dihydrochloride, while average open state probability was decreased concentration-dependently (10, 30 and 60 microM). 6. The most prominent effect of emetine dihydrochloride on single channel current was an increase of sweeps without activity. 7. At 60 microM, emetine dihydrochloride caused a decrease of the mean open time an increase of the mean closed time. The number of openings per record and number of bursts per record were reduced. 8. It is concluded that emetine dihydrochloride produces an L-type calcium channel block which might contribute to its cardiac side effects. PMID:8789394

  5. Exercise enclosures for guinea pigs.

    PubMed

    Brown, Cyndi

    2009-11-01

    Exercise and exploration are important to the health and happiness of guinea pigs. Laboratory housing does not always provide the space necessary for such opportunities. This article presents an inexpensive, versatile option for an enclosed exercise area for the laboratory guinea pig. PMID:19847177

  6. Membrane currents underlying the modified electrical activity of guinea-pig ventricular myocytes exposed to hyperosmotic solution.

    PubMed Central

    Ogura, T; You, Y; McDonald, T F

    1997-01-01

    1. Guinea-pig ventricular myocytes were superfused with hyperosmotic (sucrose) Tyrode solution (1.2-2.8 times (T) normal osmolality) for up to 40 min. Action potentials were recorded with microelectrodes, and membrane currents with the perforated- or ruptured-patch technique. 2. Hyperosmotic treatment for 20 min shrunk cell volume and hyperpolarized the membrane. Moderate (1.2-1.5 T) treatment caused biphasic changes in action potential configuration (rapid minor shortening quickly followed by lengthening to a stable 110% control duration). Severe (2.2-2.8 T) treatment caused triphasic changes (marked early shortening, strong rebound lengthening and subsequent pronounced shortening). At peak lengthening (6-10 min) action potentials (165% control duration) had a hump near -30 mV and slowed terminal repolarization. 3. In accordance with previous studies, hyperosmotic solution inhibited the delayed rectifier K+ current, and enhanced the outward Na(+)-Ca2+ exchange current (INaCa) at plateau potentials. A novel finding was that hyperosmolality reduced the amplitude of L-type Ca2+ current (ICa,L) and slowed its rate of inactivation. Experiments on myocytes loaded with indo-1 suggest that the reduction in ICa,L is due to a rapid elevation of [Ca2+]i. 4. When impaled myocytes were preloaded with EGTA, severe hyperosmotic treatment induced a rapid monotonic shortening of the action potential to a stable 20% of control duration. Addition of external K+ quickly nulled the hyperpolarization and slowly lengthened the action potential. 5. The results suggest that modified electrical activity in osmotically shrunken myocytes is primarily caused by increases in [K+]i, [Na+]i and [Ca2+]i: (i) elevated [K+]i hyperpolarizes the membrane (which may contribute to increased [Na+]i); (ii) elevated [Na+.]i shortens all phases of the action potential (increased outward-directed INaCa); and (iii) elevated [Ca2+]i has antagonistic plateau shortening (inhibition of inward ICa,L) and plateau

  7. Buffering of calcium influx by sarcoplasmic reticulum during the action potential in guinea-pig ventricular myocytes.

    PubMed Central

    Janczewski, A M; Lakatta, E G

    1993-01-01

    1. Intracellular [Ca2+] ([Ca2+]i) transients, monitored by the fluorescent Ca2+ indicator, indo-1, and twitch contractions elicited by action potentials, by voltage clamp pulses or by rapid, brief pulses of caffeine, were measured in guinea-pig single ventricular myocytes. Experiments were designed to determine whether and to what extent the trans-sarcolemmal Ca2+ influx is immediately sequestered by the sarcoplasmic reticulum (SR). 2. Rapid, brief (100-200 ms) pulses of caffeine onto a rested myocyte elicited a [Ca2+]i transient and a contraction. Following exposure to specific SR inhibitors, ryanodine (100 nM) or thapsigargin (200 nM), the rapid application of caffeine onto a rested myocyte failed to elicit changes in [Ca2+]i or in cell length, indicating that caffeine increases [Ca2+]i by specifically discharging Ca2+ from the SR. In the absence of these inhibitors, a second pulse of caffeine, within 3 min following a prior pulse, failed to elicit a [Ca2+]i transient or contraction, indicating that a caffeine pulse depletes the SR releasable Ca2+ pool. 3. Following Ca2+ depletion of the SR by double caffeine pulses at rest, an electrical stimulation elicited a slow increase in [Ca2+]i, and, after a delay, a small, slow twitch contraction. The simultaneous application of caffeine and electrical stimulation of cells in which the SR was Ca2+ depleted elicited [Ca2+]i transients with an increased rate of rise and a larger amplitude (53 +/- 8 and 63 +/- 9% respectively; mean +/- S.E.M., n = 21) than those elicited by electrical stimulation alone. 4. Whether caffeine affected the L-type calcium current (ICa) elicited by electrical stimulation was determined under whole-cell voltage clamp. A caffeine pulse delivered at the onset of a depolarizing voltage clamp step also increased the rates of rise and the amplitudes of the [Ca2+]i transients and twitch contractions in cells in which the SR was depleted of Ca2+. However, Ca2+ influx via ICa decreased when caffeine was

  8. Total and free myoplasmic calcium during a contraction cycle: x-ray microanalysis in guinea-pig ventricular myocytes.

    PubMed Central

    Wendt-Gallitelli, M F; Isenberg, G

    1991-01-01

    1. At 36 degrees C and 2 mM [Ca2+]o single guinea-pig ventricular myocytes were voltage clamped with patch electrodes. With a paired-pulse protocol applied at 1 Hz, a first pulse to +5 mV was followed by a second pulse to +50 mV. When paired pulsing had potentiated the contraction to the maximum, the cells were shock-frozen for electron-probe microanalysis (EPMA). Shock-freezing was timed at the end of diastole (-80 mV) or at different times during systole (+5 mV). 2. The same paired-pulse protocol was applied to another group of myocytes from which contraction and [Ca2+]i was estimated by microfluospectroscopy (50 microM-Na5-Indo-1). Potentiation moderately reduced diastolic sarcomere length from 1.85 to 1.82 microns and increased diastolic [Ca2+]i from about 95 to 180 nM. In potentiated cells, during the first pulse, contraction peaked within 128 +/- 25 ms after start of depolarization. [Ca2+]i peaked within 25 ms to 890 +/- 220 nM (mean +/- S.E.M.) and fell within 100 ms to about 450 nM. 3. Sigma Camyo, the total calcium concentration in the overlapping myofilaments (A-band), was measured by EPMA in seventeen potentiated myocytes. During diastole, sigma Camyo was 2.6 +/- 0.4 mmol (kg dry weight (DW]-1 which can be converted to 0.65 mM (mmoles per litre myofibrillar space). Since [Ca2+]i was 180 nM, we estimate that 99.97% of total calcium is bound. 4. A time course for systolic sigma Camyo was determined by shock-freezing thirteen cells at different times after start of depolarization to +5 mV. Sigma Camyo was 5.5 +/- 0.3 mmol (kg DW)-1 (1.4 mM) after 15-25 ms, 4.6 +/- 0.5 mmol (kg DW)-1 (1.1 mM) after 30-45 ms, and 3.1 mmol (kg DW)-1 (0.8 mM) after 60-120 ms. The fast time course of sigma Camyo suggests that calcium binds to and unbinds from troponin C at a fast rate. Hence, it is the slow kinetics of the cross-bridges that determines the 130 ms time-to-peak shortening. 5. Mitochondria of potentiated cells contained during diastole a total calcium concentration

  9. Elodontoma in Two Guinea Pigs.

    PubMed

    Capello, Vittorio; Lennox, Angela; Ghisleni, Gabriele

    2015-01-01

    Elodontoma was diagnosed in two pet guinea pigs, one involving a maxillary premolar tooth and the other affecting a mandibular incisor tooth. Diagnostic imaging, including radiographs, computed tomography, and oral endoscopy was performed in order to quantify dental disease. Diagnostic imaging was also used to guide treatment of acquired dental disease, which included intraoral restoration of normal occlusal plane and tooth extraction using an extraoral approach. These are the first histologically confirmed cases of elodontoma in guinea pigs. PMID:26415388

  10. Fendiline inhibits L-type calcium channels in guinea-pig ventricular myocytes: a whole-cell patch-clamp study.

    PubMed Central

    Tripathi, O.; Schreibmayer, W.; Tritthart, H. A.

    1993-01-01

    1. Fendiline, a diphenylalkylamine type of antianginal drug, was examined for its effects on L-type calcium channels in guinea-pig ventricular myocytes by the whole-cell patch-clamp technique. 2. Fendiline (0.3-100 microM) applied extracellularly inhibited the calcium channel current (ICa) in a concentration- and time-dependent manner. The IC50 of fendiline was 17.0 +/- 2.43 microM and the Hill slope was 1.39 +/- 0.23. 3. Inhibition of ICa by fendiline appeared with an onset of less than 3 s. 4. Fendiline inhibited ICa at all the membrane potentials tested and shifted the current-voltage curve upwards. The overall calcium channel conductance (gCa) of the cell was reduced and conductance-voltage curve was shifted to the left in the presence of fendiline. 5. Isoprenaline (0.5-1 microM), a beta-adrenoceptor agonist, partially reversed the inhibitory effect of fendiline on ICa. 6. It is suggested that fendiline applied extracellularly blocks L-type calcium channels and reduces calcium channel conductance of the cell. The calcium channels thus inhibited are, nevertheless, still available for beta-adrenoceptor stimulation. PMID:8485628

  11. Guinea Pigs: Versatile Animals for the Classroom

    ERIC Educational Resources Information Center

    Barman, Charles R.

    1977-01-01

    Guinea pigs are presented as versatile classroom animals. Suggestions for animal behavior and genetics studies are given. Also included is information concerning sex determination and the breeding of guinea pigs, and hints on keeping these animals in the classroom. References and illustrations complete the article. (MA)

  12. Guinea Pig Ciliary Muscle Development

    PubMed Central

    Pucker, Andrew D.; Carpenter, Ashley R.; McHugh, Kirk M.; Mutti, Donald O.

    2014-01-01

    Purpose The purpose of this study was to develop a method for quantifying guinea pig ciliary muscle volume (CMV) and to determine its relationship to age and ocular biometric measurements. Methods Six albino guinea pigs eyes were collected at each of five ages (n=30 eyes). Retinoscopy and photography were used to document refractive error, eye size, and eye shape. Serial sections through the excised eyes were made and then labeled with an α-smooth muscle actin antibody. The CM was then visualized with an Olympus BX51 microscope, reconstructed with Stereo Investigator (MBF Bioscience) and analyzed using Neurolucida Explorer (MBF Bioscience). Full (using all sections) and partial (using a subset of sections) reconstruction methods were used to determine CMV. Results There was no significant difference between the full and partial volume determination methods (P = 0.86). The mean CMV of the 1, 10, 20, 30, and 90-day old eyes was 0.40 ± 0.16 mm3, 0.48 ± 0.13 mm3, 0.67 ± 0.15 mm3, 0.86 ± 0.35 mm3, and 1.09 ± 0.63 mm3, respectively. CMV was significantly correlated with log age (P = 0.001), ocular length (P = 0.003), limbal circumference (P = 0.01), and equatorial diameter (P = 0.003). It was not correlated with refractive error (P = 0.73) or eye shape (P = 0.60). Multivariate regression determined that biometric variables were not significantly associated with CMV after adjustment for age. Conclusions Three-dimensional reconstruction was an effective means of determining CMV. These data provide evidence that CM growth occurs with age in tandem with eye size in normal albino guinea pigs. Additional work is needed to determine the relationship between CMV and abnormal ocular growth. PMID:24901488

  13. Chlorthalidone inhibits the KvLQT1 potassium current in guinea-pig ventricular myocytes and oocytes from Xenopus laevis

    PubMed Central

    Mancilla-Simbro, C; López, A; Martinez-Morales, E; Soto-Perez-de-Celis, E; Millan-PerezPeña, L; Tsushima, R; Salinas-Stefanon, E M

    2007-01-01

    Background and purpose: Chlorthalidone is used for the treatment of hypertension as it produces a lengthening of the cardiac action potential. However, there is no experimental evidence that chlorthalidone has electrophysiological effects on the potassium currents involved in cardiac repolarization. Experimental approach: Ventricular myocytes and oocytes, transfected with human ionic channels that produce IK current, were exposed to different concentrations of chlorthalidone. Action potentials and potassium currents were recorded using a patch clamp technique. To determine which component of the current was affected by chlorthalidone, human channel proteins (hERG, minK and KvLQT1) were used. Key results: Chlorthalidone prolonged the ventricular action potential at 50 and 90% by 13 and 14%, respectively. The cardiac potassium currents I to and IK1 were not affected by chlorthalidone at any concentration, whereas the delayed rectifier potassium current, IK, was blocked in a dose-response, voltage-independent fashion. In our preparation, 100 μM chlorthalidone blocked the two components of the delayed rectifier potassium current with the same potency (50.1±5% for IKr and 54.6±6% for IKs) (n=7, P<0.05). The chlorthalidone-sensitive current was slow and saturated at potentials greater than +30 mV. In our conditions only the KvLQT1 potassium current was affected by the drug, by 14%. Conclusions and implications: Chlorthalidone was demonstrated to have a direct effect on cardiac ventricular myocytes; it blocked the delayed rectifier potassium current (IK), specifically the KvLQT1 component of the potassium current. These results indicate that it has potential for use as an antiarrhythmic but further studies are needed. PMID:18037918

  14. Imaging of calcium wave propagation in guinea-pig ventricular cell pairs by confocal laser scanning microscopy.

    PubMed

    Takamatsu, T; Minamikawa, T; Kawachi, H; Fujita, S

    1991-08-01

    We describe here the use of a confocal laser scanning microscope for imaging fast dynamic changes of the intracellular calcium ion concentration ([Ca2+]i) in isolated ventricular cell pairs. The scanning apparatus of our system, paired galvanometer mirrors, can perform narrow band scanning of an area of interest at a high temporal resolution of less than 70 msec per image. The actual [Ca2+]i is obtained directly through the fluorescence intensity of injected fluo-3, which responds to changes of [Ca2+]i in optically sectioned unit volumes of the cell. Images of the calcium wave obtained during propagation between paired cells revealed that the wavefront is constant in shape and propagates at constant velocity without any delay at the cell-to-cell junction. The confocal laser scanning microscope with depth-discriminating ability is a valuable tool for taking pictures of the sequence of biological events in living cells. PMID:1782671

  15. Inhibition of the sodium pump in guinea-pig ventricular muscle by dihydro-ouabain: effects of external potassium and sodium.

    PubMed Central

    Daut, J

    1983-01-01

    The inhibition of the electrogenic pump current in quiescent guinea-pig ventricular muscle by dihydro-ouabain (DHO) was studied with the three-micro-electrode voltage-clamp technique described previously (Daut, 1982c). From dose-response curves of the drug-induced current change (ID) the equilibrium dissociation constant of the binding of DHO to the Na-K pump (KD) and the electrogenic pump current flowing in the steady state (Ip) were inferred (Daut & Rüdel, 1982b). The external K concentration ([K]o) was varied between 2 and 4.5 mM (substituted by Na). KD was found to increase with increasing [K]o. A plot of log KD versus log [K]o gave a straight line with a slope of about 1.5. The time constants of the onset (tau on) and decay (tau off) of ID are supposed to represent the chemical kinetics of binding and unbinding of the drug (Daut & Rüdel, 1981, 1982b). Tau on was found to be inversely related to [K]o whereas tau off was found to be independent of [K]o. Ip was found to be independent of [K]o. This was interpreted to indicate that in the steady state Ip is mainly determined by the passive influx of Na into the cell, which may be relatively insensitive to small changes in [K]o. The effects of [K]o on the drug-induced current change are consistent with competitive inhibition of the binding of DHO to the Na-K pump. It is suggested that K ions and cardiac glycosides compete for extracellular binding sites on the same conformation of the Na-K pump. The external Na concentration ([Na]o) was varied between 147 and 49 mM (substituted by choline or Tris). Reduction of [Na]o produced a proportional decrease of Ip. This may be a consequence of the accompanying reduction of passive Na influx and the resulting decrease in intracellular Na activity (alpha iNa). Reduction of [Na]o markedly increased KD. This effect may be mediated by competition between Na and K at the K-loading sites of the pump and/or by separate modulatory Na-binding sites. It is concluded that the well

  16. Contractions in guinea-pig ventricular myocytes triggered by a calcium-release mechanism separate from Na+ and L-currents.

    PubMed Central

    Ferrier, G R; Howlett, S E

    1995-01-01

    1. Unloaded cell shortening and membrane currents were examined in isolated guinea-pig ventricular myocytes at 37 degrees C using video edge detection and single-electrode voltage clamp. 2. Inward Na+ currents were eliminated by lidocaine, tetrodotoxin, replacement of extracellular Na+ with choline chloride or sucrose, or by voltage inactivation of Na+ channels. In the absence of Na+ current, the threshold for contraction was approximately -50 or -55 mV. 3. Verapamil (5 microM) and nifedipine (2 microM) failed to inhibit contractions at negative membrane potentials when positive conditioning pulses were used to maintain intracellular Ca2+ stores via Na(+)-Ca2+ exchange. In contrast, 200 microM Ni2+ inhibited these contractions. 4. Contractions were abolished when the extracellular solution was nominally Ca2+ free. However, contractions were restored by as little as 50 microM extracellular Ca2+. 5. Ryanodine (30 nM) completely abolished contractions initiated by depolarizing steps from -65 to -40 mV, but had minimal effects on contractions initiated by depolarizing steps from -40 to +5 mV. Subtraction of contraction-voltage relations determined in the presence of ryanodine from control relations revealed a ryanodine-sensitive component of contraction. This component activated at -55 mV and reached a plateau near -25 mV. 6. The amplitudes of contractions initiated by depolarizing steps from -40 mV were directly proportional to the magnitude of Ca2+ current (ICa). In contrast, contractions initiated by steps from either -55 or -65 mV were not proportional to ICa. These contractions appeared at potentials negative to the threshold for L-type Ca2+ current, increased to a plateau at more positive potentials and did not decrease at potentials at which ICa decreased. 7. Subtraction of the contraction-voltage relationship determined from a membrane potential of -40 mV from that at -55 mV revealed a component of contraction with a negative activation threshold whose

  17. Differential effects of L-propionylcarnitine on the electrical and mechanical properties of guinea pig ventricular muscle in normal and acidic conditions.

    PubMed

    Aomine, M; Arita, M

    1987-11-01

    We studied the effects of L-propionylcarnitine (PC) on transmembrane action potentials and isometric contractile tension in isolated guinea pig ventricular papillary muscles. The effects of 5 concentrations of PC (10(-5), 10(-4), 10(-3), 10(-2) and 3 X 10(-2)M) were examined in both normal (pH 7.4) and acidic (pH 6.9) conditions. The concentrations of 10(-5) to 10(-2)M had no significant effect on action potential amplitude, maximum upstroke velocity of phase 0 and resting potential, in either condition. At pH 7.4, action potential duration (ADP) was significantly (P less than 0.05) or insignificantly shortened by the drug depending upon the concentration used. At pH 6.9, however, the APD was prolonged by moderate PC concentrations (10(-3) and 10(-2)M), in which the effective refractory period (ERP) was also lengthened, associated with an increased ERP/APD ratio. In both pH conditions, the highest concentration (3 X 10(-2)M) significantly (P less than 0.05) decreased all these action potential parameters. PC had a biphasic effect on the developed tension. In both pH conditions, low PC concentrations (10(-5) to 10(-3)M) produced an initial augmentation of the contraction, followed by subsequent reduction. The initial augmentation disappeared by pretreatment with reserpine or propranolol, suggesting the involvement of beta-adrenoceptors. In the steady state, all PC concentrations produced a negative inotropic effect at pH 7.4, while at pH 6.9 only high concentrations (10(-2)M and 3 X 10(-2)M) had this effect. These results suggest that the effects of PC in an acidic condition differ considerably from those in a normal pH condition and that limited concentrations of PC (10(-3) to 10(-2)M) may prevent re-entrant arrhythmias from developing under acidic conditions via lengthening of the ERP, without deleterious effects on the contractile force. PMID:3430099

  18. Animal models of tuberculosis: Guinea pigs.

    PubMed

    Clark, Simon; Hall, Yper; Williams, Ann

    2015-05-01

    The progression of the disease that follows infection of guinea pigs with Mycobacterium tuberculosis displays many features of human tuberculosis (TB), and the guinea pig model of TB has been used for more than 100 years as a research tool to understand and describe disease mechanisms. Changes in the bacterial burden and pathology following infection can be readily monitored and used to evaluate the impact of TB interventions. Demonstration of the protective efficacy of vaccines in the low-dose aerosol guinea pig model is an important component of the preclinical data package for novel vaccines in development, and there is a continual need to improve the model to facilitate progression of vaccines to the clinic. Development of better tools with which to dissect the immune responses of guinea pigs is a focus of current research. PMID:25524720

  19. Using guinea pigs in studies relevant to asthma and COPD

    PubMed Central

    Canning, Brendan J.; Chou, Yangling

    2010-01-01

    The guinea pig has been the most commonly used small animal species in preclinical studies related to asthma and COPD. The primary advantages of the guinea pig are the similar potencies and efficacies of agonists and antagonists in human and guinea pig airways and the many similarities in physiological processes, especially airway autonomic control and the response to allergen. The primary disadvantages to using guinea pigs are the lack of transgenic methods, limited numbers of guinea pig strains for comparative studies and a prominent axon reflex that is unlikely to be present in human airways. These attributes and various models developed in guinea pigs are discussed. PMID:18462968

  20. 9 CFR 113.38 - Guinea pig safety test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... be injected either intramuscularly or subcutaneously into each of two guinea pigs and the animals... pigs during the observation period, the serial or subserial is unsatisfactory. If unfavorable reactions... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Guinea pig safety test. 113.38...

  1. 9 CFR 113.38 - Guinea pig safety test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... be injected either intramuscularly or subcutaneously into each of two guinea pigs and the animals... pigs during the observation period, the serial or subserial is unsatisfactory. If unfavorable reactions... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Guinea pig safety test. 113.38...

  2. The cochleogram of the guinea pig.

    PubMed

    Linss, Volker; Linss, Werner; Emmerich, Edeltraut; Richter, Frank

    2007-04-01

    The cochleogram is an important tool to relate properties of the cochlea (e.g. hair cell loss, damaged hair cells) to their position in the cochlear turns, to calculate the average hair cell density, and to measure the length of the whole cochlea. In this work different methods of plotting cochleograms are compared. We suggest that a sector-wise division of the cochlea for counting a cochleogram has advantages over line diagrams that provide a higher spatial resolution but might lead to misinterpretations of the degree of missing hair cells. The scanning electron microscopic analysis of 171 guinea pig cochleas revealed a mean basilar membrane length of 16.4 +/- 1.4 mm (mean +/- standard deviation) with sector lengths of 6.9, 4.2, 3.2, and 1.9 mm, thus adding relevant information to the morphology of the guinea pig cochlea. PMID:17082943

  3. Endogenous prostaglandin in guinea pig taenia coli.

    PubMed

    Yamaguchi, T; Hitzig, B; Coburn, R F

    1976-01-01

    Prostaglandin (PGE) is synthesized in the guinea pig taenia coli. A low threshold concentration for an effect of exogenous PGE1 or PGE2 on spontaneous mechanical activity was demonstrated. The PG synthetase inhibitors aspirin, indomethacin, and 5,8,11,14-eicosatetraynoic acid, at concentrations that inhibited PGE efflux, had effects on spontaneous mechanical activity, membrane potential, membrane resistance, and evoked and spontaneous action potentials (single and double sucrose-gap methods) that were consistent with an action due to inhibition of membrane PGE concentration. The threshold concentration of indomethacin, which inhibited PGE efflux, was the same as the concentration that inhibited spontaneous mechanical activity. Pretreatment with ouabain (10(-6)-10(-5) g/ml) or elevated extracellular K+ (29 and 126 mM) made the guinea pig taenia coli entirely refractory to exogenous PGE1 or PGE2; the mechanical effects of the three prostaglandin synthetase inhibitors also were absent in the presence of elevated K+ or ouabain. The data are consistent with a hypothesis that, under conditions of our experiments, endogenous PGE has an effect on resting tension and spontaneous mechanical activity and on properties of the surface membrane of the guinea pig taenia coli. PMID:1251900

  4. A 2-D guinea pig lung proteome map

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Guinea pigs represent an important model for a number of infectious and non-infectious pulmonary diseases. The guinea pig genome has recently been sequenced to full coverage, opening up new research avenues using genomics, transcriptomics and proteomics techniques in this species. In order to furth...

  5. The Guinea Pigs of a Problem-Based Learning Curriculum

    ERIC Educational Resources Information Center

    Reddy, Sarasvathie; McKenna, Sioux

    2016-01-01

    Participants in a study on learning the clinical aspects of medicine in a problem-based learning (PBL) curriculum repeatedly referred to themselves as "Guinea pigs" at the mercy of a curriculum experiment. This article interrogates and problematises the "Guinea pig" identity ascribed to and assumed by the first cohort of…

  6. 9 CFR 113.38 - Guinea pig safety test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Guinea pig safety test. 113.38 Section 113.38 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Standard Procedures § 113.38 Guinea pig safety...

  7. Spontaneous reproductive tract leiomyomas in aged guinea-pigs.

    PubMed

    Field, K J; Griffith, J W; Lang, C M

    1989-10-01

    Seven of 83 female guinea-pigs were found to have reproductive tract leiomyomas at necropsy. Sixty-three of these guinea-pigs also had cystic rete ovarii. Eleven separate leiomyomas were identified, the most common site of formation being the uterine body or horn. The tumours contained histological evidence of smooth muscle, abundant fibrous connective tissue and occasional foci of fibrocartilage and bone. Mitotic figures were identified in only one tumour. The mean age of guinea-pigs with leiomyomas was 47.6 months, and the mean age of the study population was 33.1 months. Two other reproductive tract tumours identified in the 83 guinea-pigs were an ovarian teratoma and a cavernous haemangioma. These data indicate that leiomyomas are the most common reproductive tract tumour in this colony of aged female guinea-pigs and that they are frequently seen in conjunction with cystic rete ovarii. PMID:2584448

  8. Biosynthesis of plasmenylcholine in guinea pig heart

    SciTech Connect

    Wientzek, M.; Choy, P.C.

    1986-05-01

    In some mammalian hearts, up to 40% of the choline phosphoglyceride (CPG) exists as plasmenylcholine (1-alkenyl-2-acyl-glycero-3-phosphocholine). Although the majority of diacylphosphatidylcholine (PC) in mammalian hearts is synthesized from choline via the CDP-choline pathway, the formation of plasmenylcholine from choline was not known. In this study, they investigated the biosynthesis of plasmenyl-choline in the isolated guinea pig heart by perfusion with (/sup 3/H)choline. Labelled choline containing metabolites and labelled plasmenylcholine were isolated and determined at different perfusion time points. Significant amounts of labelling were found only in choline, phosphocholine, CDP-choline, plasmenyl-choline and PC. In addition, a precursor-product relationship was observed between the labelling of CDP-choline and plasmenylcholine. Such a relationship was not observed between choline and plasmenylcholine. Hence, they postulate that the incorporation of choline into plasmenylcholine is via the CDP-choline pathway and not via base exchange. The ability to condense 1-alkenyl-2-acyl-glycerol with CDP-choline was also demonstrated in vitro with guinea pig heart microsomes.

  9. Experimental poisoning of guinea pig (Cavia porcellus) with Indigofera suffruticosa.

    PubMed

    Salvador, I S; Medeiros, R M T; Pessoa, C R M; Oliveira, D M; Duarte, A L A; Fighera, R A; Riet-Correa, F

    2011-05-01

    Indigofera suffruticosa causes hemolytic anemia and hemoglobinuria in cattle. The plant was administered to six groups of two guinea pigs each, at the daily dose of 10 g/kg body weight, for periods of 2, 4, 6, 8, 10 and 15 days. The guinea pigs progressively developed reduced hematocrits and hemoglobin concentrations, and finally presented anemia, without hemoglobinuria. Urine passed by guinea pigs that had ingested the plant for more than 24 h acquired a turquoise blue pigmentation 8-10 h after urination. It is suggested that the anemia is caused by the aniline contained in I. suffruticosa. PMID:21396390

  10. Radiation-induced micrencephaly in guinea pigs

    SciTech Connect

    Wagner, L.K.; Johnston, D.A.; Felleman, D.J.

    1992-11-01

    The effect of x rays on brain weight of guinea pig pups at birth was studied for 21-day old embroys exposed in utero to doses of 75 and 100 mGy. When compared to controls and when corrected for body weight, gestation time, litter size, sex, and examiner differences the brains of irradiated pups weighed approximately 46 mg less than those of controls (p<0.001) for the 75-mGy group and about 55 mg less for the 100-mGy group. Brains of females weighed 51 mg less than those of males of the same body weight. Dam weight and caging conditions had no observed effect on brain weight.

  11. Radiation-induced micrencephaly in guinea pigs

    SciTech Connect

    Wagner, L.K.; Johnston, D.A.; Felleman, D.J.

    1992-01-01

    The effect of x rays on brain weight of guinea pig pups at birth was studied for 21-day old embroys exposed in utero to doses of 75 and 100 mGy. When compared to controls and when corrected for body weight, gestation time, litter size, sex, and examiner differences the brains of irradiated pups weighed approximately 46 mg less than those of controls (p<0.001) for the 75-mGy group and about 55 mg less for the 100-mGy group. Brains of females weighed 51 mg less than those of males of the same body weight. Dam weight and caging conditions had no observed effect on brain weight.

  12. "Human guinea pigs"--a history.

    PubMed

    Pappworth, M H

    In 1967, Pappworth expanded a 1962 journal article on unethical experiments with human subjects into a book, Human Guinea Pigs: Experimentation on Man (Routledge). Here Pappworth describes the impetus behind his controversial article and book, and the reaction to both from the British media, the British medical establishment, the Ministry of Health, and Parliament. He discusses the effectiveness of ethical codes, editorial policies, and research ethics committees in safeguarding human subjects from overzealous or unethical researchers. He warns of the need for all those involved in human experimentation -- researchers, their units, ethics committees, editors of medical journals -- to tighten the self regulatory mechanisms in place lest public reaction to unethical research bring on legal sanctions. PMID:2279175

  13. Antitussive Effects of Memantine in Guinea Pigs

    PubMed Central

    Smith, Jaclyn A.; Hilton, Emma C. Y.; Saulsberry, Loren

    2012-01-01

    Background: The treatment of cough is a significant clinical unmet need because there is little evidence that current therapies are effective. Based on evidence supporting a role for N-methyl d-aspartate receptors (NMDARs) in cough, we hypothesized that memantine, a low-affinity, uncompetitive NMDAR channel blocker in routine use for the treatment of Alzheimer disease, could be an effective, well-tolerated, antitussive therapy. The aim of this study was to establish preclinical evidence that memantine has antitussive effects. Methods: We studied the influence of memantine on experimentally induced coughing in response to citric acid and bradykinin inhalation in guinea pigs. We also compared the potency and efficacy of memantine as an antitussive to other NMDAR antagonists, dextromethorphan and ketamine, and to the γ-aminobutyric acid class B receptor agonist baclofen. Results: Compared with control subjects, 10 mg/kg memantine significantly reduced the cumulative number of coughs evoked by both citric acid (median, 24.0 [interquartile range (IQR), 13.0-25.5] vs 1.5 [IQR, 0.3-10.3] coughs; P = .012) and bradykinin aerosols (median, 16.0 [IQR, 9.5-18.5] vs 0.0 [IQR, 0-0.75] coughs; P = .002). Memantine 10 mg/kg produced a similar reduction in the cumulative number of coughs to baclofen 3 mg/kg and demonstrated comparatively greater cough suppression than 30 mg/kg dextromethorphan or 30 mg/kg ketamine. This dose of memantine produced no sedative or respiratory depressive effects. Conclusions: This study illustrates that memantine has marked antitussive effects in guinea pigs, most likely mediated through NMDAR channel blockade. Memantine, therefore, has the potential to be a safe, effective, and well-tolerated antitussive agent. PMID:22016492

  14. Generation of DPOAEs in the guinea pig.

    PubMed

    Withnell, Robert H; Shaffer, Lauren A; Talmadge, Carrick L

    2003-04-01

    In humans, distortion product otoacoustic emissions (DPOAEs) at frequencies lower than the f(2) stimulus frequency are a composite of two separate sources, these two sources involving two distinctly different mechanisms for their production: non-linear distortion and linear coherent reflection [Talmadge et al., J. Acoust. Soc. Am. 104 (1998) 1517-1543; Talmadge et al., J. Acoust. Soc. Am. 105 (1999) 275-292; Shera and Guinan, J. Acoust. Soc. Am. 105 (1999) 332-348; Kalluri and Shera, J. Acoust. Soc. Am. 109 (2001) 662-637]. In rodents, DPOAEs are larger, consistent with broader filters; however the evidence for two separate mechanisms of DPOAE production as seen in humans is limited. In this study, we report DPOAE amplitude and phase fine structure from the guinea pig with f(2)/f(1) held constant at 1.2 and f(2) swept over a range of frequencies. Inverse Fast Fourier Transform analysis and time-domain windowing were used to separate the two components. Both the 2f(1)-f(2) DPOAE and the 2f(2)-f(1) DPOAE were examined. It was found that, commensurate with human data, the guinea pig DPOAE is a composite of two components arising from different mechanisms. It would appear that the 2f(1)-f(2) emission measured in the ear canal is usually dominated by non-linear distortion, at least for a stimulus frequency ratio of 1.2. The 2f(2)-f(1) DPOAE exhibits amplitude fine structure that, for the animals examined, is predominantly due to the variation in amplitude of the place-fixed component. Cochlear delay times appear consistent with a linear coherent reflection mechanism from the distortion product place for both the 2f(1)-f(2) and 2f(2)-f(1) place-fixed components. PMID:12684183

  15. Guinea-pig productivity under traditional management.

    PubMed

    Manjeli, Y; Tchoumboue, J; Njwe, R M; Teguia, A

    1998-04-01

    Results of a 12 month study of traditional guinea-pig production in the western highlands of Cameroon are reported. The mean age of guinea-pigs (Cavia porcellus L.) at first parturition, kidding interval and litter size at birth were 126.30 +/- 10.40 d, 64.8 +/- 1.70 d and 1.63 +/- 0.26 kids respectively. The annual reproductive rate was 9.18 kids/breeding doe while the doe post-partum weight was 530 g. Mean body weights at birth, presumed weaning (21 d) and 15 weeks of age were 78.36 +/- 3.20, 147.51 +/- 8.10 and 418.88 +/- 32 g respectively. Type of birth and sex had a significant effect on body weight at all ages. Birth weight dropped significantly from 83.88 +/- 2.87 g for singles to 81.57 +/- 3.40 g for twins, 74.25 +/- 2.39 g for triplets and 73.75 +/- 4.12 g for quadruplets. These differences were maintained to maturity (15 weeks). Males were generally heavier than females. Mortality rates were relatively high among kids: 24% at birth, 39% at 3 weeks and 40% at 15 weeks. Productivity indices were 0.827 kg of young weaned per doe per year, 1560 g of young weaned per kg of doe per year and 2.52 kg of young weaned per kg metabolic weight (kg 0.75) of female per year. PMID:9719838

  16. Absence of pork-like insulin in guinea pig tissues.

    PubMed Central

    Eng, J; Yalow, R S

    1982-01-01

    By using a technique for concentrating insulin 100-fold from tissue extracts with 75-95% recoveries, we earlier failed to detect pork-like insulin in guinea pig tissues and thus were unable to confirm reports from the National Institutes of Health that these tissues contain a pork-like insulin at concentrations averaging 1 ng/g. This difference could have been due to differences in strains of guinea pigs studied or in the species specificities of the antisera used for radioimmunoassay. In the current study, tissue extracts from both NIH and Hartley guinea pigs were assayed with three antisera routinely used in our laboratory and one antiserum that had been used in the National Institutes of Health laboratory. We observed that pork-like insulin in tissues from both strains of guinea pigs as determined with the four antisera is less than 0.02 ng/g. We therefore conclude that is is unlikely that nonpancreatic guinea pig tissues contain or synthesize a peptide resembling pork or other non-guinea pig mammalian insulin. PMID:7045868

  17. Pathogenesis of Lassa virus infection in guinea pigs.

    PubMed Central

    Jahrling, P B; Smith, S; Hesse, R A; Rhoderick, J B

    1982-01-01

    A rodent model for human Lassa fever was developed which uses inbred (strain 13) and outbred (Hartley) guinea pigs. Strain 13 guinea pigs were uniformly susceptible to lethal infection by 2 or more PFU of Lassa virus strain Josiah. In contrast, no more than 30% of the Hartley guinea pigs died regardless of the virus dose. In lethally infected strain 13 guinea pigs, peak titers of virus (10(7) to 10(8) PFU) occurred in the spleen and lymph nodes at 8 to 9 days, in the salivary glands at 11 days, and in the lung at 14 to 16 days. Virus reached low titers (10(4) PFU) in the plasma and brain and intermediate titers in the liver, adrenal glands, kidney, pancreas, and heart. In moribund animals, the most consistent and severe histological lesion as an interstitial pneumonia. In contrast, the brain was only minimally involved. The immune response of lethally infected strain 13 guinea pigs, as measured by the indirect fluorescent antibody test, was detectable within 10 days of infection and was similar in timing and intensity to the fluorescent antibody test response of both lethally infected and surviving outbred animals. In contrast to the fluorescent antibody response, neutralizing antibody developed late in convalescence and was thus detected only in surviving outbred guinea pigs. The availability of a rodent model for human Lassa fever in uniformly susceptible strain 13 guinea pigs should facilitate detailed pathophysiological studies and efficacy testing of antiviral drugs, candidate vaccines, and immunotherapy regimens to develop control methods for this life-threatening disease in humans. Images PMID:6749685

  18. Radiation induced micrencephaly in guinea pigs

    SciTech Connect

    Wagner, L.K.; Johnston, D.A.; Felleman, D.J.

    1991-01-01

    A brain weight deficit of about 70 mg was induced at doses of approximately 75-mGy and a deficit of 60 mg was induced at 100 mGy. This confirms the effects projected and observed by Wanner and Edwards. Although the data do not demonstrate a clear dose-response relationship between the 75-mGy and 100-mGy groups, the data are statistically consistent with a dose-response effect because of the overlapping confidence intervals. The lack of a statistically significant observation is most likely related to the small difference in doses and the limited numbers of animals examined. There are several factors that can influence the brain weight of guinea pig pups, such as caging and housing conditions, the sex of the animal, and litter size. These should be taken into account for accurate analysis. Dam weight did not appear to have a significant effect. The confirmation of a micrencephalic effect induced x rays at doses of 75-mGy during this late embryonic stage of development is consistent with the findings of small head size induced in those exposed prior to the eight week of conception at Hiroshima. This implies a mechanism for micrencephaly different from those previously suggested and lends credence to a causal relation between radiation and small head size in humans at low doses as reported by Miller and Mulvihill. 16 refs., 13 tabs.

  19. Hypervitaminosis D in Guinea Pigs with α-Mannosidosis

    PubMed Central

    Jensen, JanLee A; Brice, Angela K; Bagel, Jessica H; Mexas, Angela M; Yoon, Sea Young; Wolfe, John H

    2013-01-01

    A colony of guinea pigs (n = 9) with α-mannosidosis was fed a pelleted commercial laboratory guinea pig diet. Over 2 mo, all 9 guinea pigs unexpectedly showed anorexia and weight loss (11.7% to 30.0% of baseline weight), and 3 animals demonstrated transient polyuria and polydipsia. Blood chemistry panels in these 3 guinea pigs revealed high-normal total calcium, high-normal phosphate, and high ALP. Urine specific gravity was dilute (1.003, 1.009, 1.013) in the 3 animals tested. Postmortem examination of 7 animals that were euthanized after failing to respond to supportive care revealed renal interstitial fibrosis with tubular mineralization, soft tissue mineralization in multiple organs, hepatic lipidosis, and pneumonia. Analysis of the pelleted diet revealed that it had been formulated with a vitamin D3 content of more than 150 times the normal concentration. Ionized calcium and 25-hydroxyvitamin D values were both high in serum saved from 2 euthanized animals, confirming the diagnosis of hypervitaminosis D. This report discusses the clinical signs, blood chemistry results, and gross and histologic findings of hypervitaminosis D in a colony of guinea pigs. When unexpected signs occur colony-wide, dietary differentials should be investigated at an early time point. PMID:23582422

  20. An ecologically relevant guinea pig model of fetal behavior

    PubMed Central

    Bellinger, S. A.; Lucas, D.; Kleven, G. A.

    2015-01-01

    The laboratory guinea pig, Cavia porcellus, shares with humans many similarities during pregnancy and prenatal development, including precocial offspring and social dependence. These similarities suggest the guinea pig as a promising model of fetal behavioral development as well. Using innovative methods of behavioral acclimation, fetal offspring of female IAF hairless guinea pigs time mated to NIH multi-colored Hartley males were observed longitudinally without restraint using noninvasive ultrasound at weekly intervals across the 10 week gestation. To insure that the ultrasound procedure did not cause significant stress, salivary cortisol was collected both before and after each observation. Measures of fetal spontaneous movement and behavioral state were quantified from video recordings from week 3 through the last week before birth. Results from prenatal quantification of Interlimb Movement Synchrony and state organization reveal guinea pig fetal development to be strikingly similar to that previously reported for other rodents and preterm human infants. Salivary cortisol readings taken before and after sonography did not differ at any observation time point. These results suggest this model holds translational promise for studying the prenatal mechanisms of neurobehavioral development, including those that may result from adverse events. Because the guinea pig is a highly social mammal with a wide range of socially oriented vocalizations, this model may also have utility for studying the prenatal origins and trajectories of developmental disabilities with social-emotional components, such as autism. PMID:25655512

  1. Pharmacologically Stimulated Pupil and Accommodative Changes in Guinea Pigs

    PubMed Central

    Ostrin, Lisa A.; Garcia, Mariana B.; Choh, Vivian; Wildsoet, Christine F.

    2014-01-01

    Purpose. The guinea pig is being used increasingly as a model of human myopia. As accommodation may influence the effects of manipulations used in experimental myopia models, understanding the accommodative ability of guinea pigs is important. Here, nonselective muscarinic agonists were used as pharmacological tools to study guinea pig accommodation. Methods. Measurements were made on 15 pigmented guinea pigs. For in vivo testing, animals were anesthetized and, following baseline measurements, 2% pilocarpine was applied topically. Measurements included A-scan ultrasonography, optical coherence tomography (OCT) imaging, corneal topography, and refraction. In vitro lens scanning experiments were performed using anterior segment preparations, with measurements before and during exposure to carbachol. Anterior segment structures were examined histologically and immunohistochemistry was done to characterize the muscarinic receptor subtypes present. Results. In vivo, pilocarpine induced a myopic shift in refractive error coupled to a small, but consistent decrease in anterior chamber depth (ACD), a smaller and more variable increase in lens thickness, and a decrease in pupil size. Lens thickness increases were short-lived (10 minutes), while ACD and pupil size decreased over 20 minutes. Corneal curvature was not significantly affected. Carbachol tested on anterior segment preparations in vitro was without effect on lens back vertex distance, but did stimulate pupil constriction. Immunohistochemistry indicated the presence of muscarinic receptor subtypes 1 to 5 in the iris and ciliary body. Conclusions. The observed pilocarpine-induced changes in ACD, lens thickness, and refraction are consistent with active accommodation in the guinea pig, through cholinergic muscarinic stimulation. PMID:25097245

  2. 9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal...

  3. 9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal...

  4. 9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal...

  5. Comparison of guinea pig cytomegalovirus and guinea pig herpes-like virus: pathogenesis and persistence in experimentally infected animals.

    PubMed Central

    Tenser, R B; Hsiung, G D

    1976-01-01

    The pathogenesis of guinea pig cytomegalovirus (GPCMV) and guinea pig herpes-like virus (GPHLV) in guinea pigs was compared. Animals were inoculated with the two viruses by different routes and sacrificed after varying periods of time. GPCMV was consistently isolated from salivary gland 2 weeks postinoculation and thereafter following intraperitoneal or subcutaneous incoulaton. Virus was less frequently found in other tissues including blood, spleen, and kidney. Intranuclear inclusions were seen in tissue sections of salivary gland after inoculation with GPCMV- infected tissue suspension, but were only rarely found after inoculation with tissue culture virus. In GPHLV-infected guinea pigs, consistent latent infection of leukocytes and other tissues was detected by cocultivation techniques. Intranuclear inclusions were not found in the spleen, salivary gland, or other infected tissues after GPHLV infection with either tissue culture virus or infected tissue suspension. Guinea pigs inoculated with GPCMV produced high titers of specific neutralizing antibody to the homologous virus; those inoculated with GPHLV developed long-term viremia accompanied by minimal neutralizing antibody levels to the virus. Images PMID:178599

  6. The effects of compensated cardiac hypertrophy on dihydropyridine and ryanodine receptors in rat, ferret and guinea-pig hearts.

    PubMed

    Rannou, F; Sainte-Beuve, C; Oliviero, P; Do, E; Trouvé, P; Charlemagne, D

    1995-05-01

    The number of dihydropyridine and ryanodine receptors (DHP-R and RyR) has been measured in control and hypertrophied ventricles from rats, guinea pigs and ferrets to determine whether these two channels contribute to the alterations in excitation-contraction coupling (ECC), and in Ca2+ transient during compensated cardiac hypertrophy. We found that ventricular hypertrophy did not change the density of DHP-R. Mild hypertrophy did not alter the density of RyR in the rat but decreased it in the guinea-pig and in the ferret (30% and 36%, respectively). Severe hypertrophy decreased the density of RyR by 20% in the rat and by 34% in the guinea-pig. Therefore, the decrease is greater in ferret and guinea-pig hearts than in rat heart. We conclude that the sarcoplasmic reticulum (SR) Ca2+ release channels but not the L-type Ca2+ channels could contribute to the slowing of intracellular Ca2+ movements and to the reduced velocity of shortening of the hypertrophied hearts. We suggest that, in the guinea pig and ferret hearts which express only the beta myosin heavy chain (MHC) isoform, the reduced velocity of shortening during hypertrophy is related to the decrease in RyR density, whereas in the rat, it is regulated primarily via a shift in the MHC isoform, except in severe hypertrophy in which the moderate decrease in RyR would also be involved. PMID:7473781

  7. Effect of ouabain on mechanical and electrical properties of rat and guinea pig hearts at 180 C.

    PubMed

    Diacono, J; Dietrich, J

    1977-04-01

    The effects of ouabain 10(-6) M on rat and guinea pig hearts have been studied at 18 degrees C, in order to reduce almost fully both the Na+, K+-dependent ATPase activity and the ouabain induced inhibition of this enzyme. In isolated guinea pig hearts the positive inotropic response to ouabain obtained at 32 degrees C disappeared at 18 degrees C. On the contrary, the contractile strength of rat hearts was slightly reduced by ouabain and in the same manner at both temperatures. Current and voltage clamp experiments carried out at 18 degrees C in ventricular fibres revealed that ouabain 10(-6) M decreased both the action potential overshoot and the fast sodium current in rat and guinea pig, by reduction of the membrane sodium conductance. Ouabain did not change the calcium current in guinea pig preparations, whereas in rat heart muscle this current was reduced. The effects of ouabain on both the action potential plateau and outward repolarizing current indicated some inconsistencies from preparation to preparation and cannot therefore be considered as significant. The persistence of the ouabain induced alterations of g Na (in rat and guinea pig) and calcium current (in rat) at 18 degrees C supports the hypothesis of two ouabain cell receptors in heart muscle. PMID:141917

  8. Parainfluenza 3-Induced Cough Hypersensitivity in the Guinea Pig Airways.

    PubMed

    Zaccone, Eric J; Lieu, TinaMarie; Muroi, Yukiko; Potenzieri, Carl; Undem, Blair E; Gao, Peisong; Han, Liang; Canning, Brendan J; Undem, Bradley J

    2016-01-01

    The effect of respiratory tract viral infection on evoked cough in guinea pigs was evaluated. Guinea pigs were inoculated intranasally with either parainfluenza type 3 (PIV3) and cough was quantified in conscious animals. The guinea pigs infected with PIV3 (day 4) coughed nearly three times more than those treated with the viral growth medium in response to capsaicin, citric acid, and bradykinin. Since capsaicin, citric acid, and bradykinin evoked coughing in guinea pigs can be inhibited by drugs that antagonize the transient receptor potential cation channel, subfamily V, member 1 (TRPV1), it was reasoned that the virally-induced hypertussive state may involve alterations in TPRV1 activity. PIV3 infection caused a phenotypic switch in tracheal nodose Aδ "cough receptors" such that nearly 50% of neurons began to express, de novo, TRPV1 mRNA. There was also an increase TRPV1 expression in jugular C-fiber neurons as determined by qPCR. It has previously been reported that tracheal-specific nodose neurons express the BDNF receptor TrkB and jugular neurons express the NGF receptor TrkA. Jugular neurons also express the artemin receptor GFRα3. All these neurotrophic factors have been associated with increases in TRPV1 expression. In an ex vivo perfused guinea pig tracheal preparation, we demonstrated that within 8 h of PIV3 infusion there was no change in NGF mRNA expression, but there was nearly a 10-fold increase in BDNF mRNA in the tissue, and a small but significant elevation in the expression of artemin mRNA. In summary, PIV3 infection leads to elevations in TRPV1 expression in the two key cough evoking nerve subtypes in the guinea pig trachea, and this is associated with a hypertussive state with respect to various TRPV1 activating stimuli. PMID:27213574

  9. Parainfluenza 3-Induced Cough Hypersensitivity in the Guinea Pig Airways

    PubMed Central

    Lieu, TinaMarie; Muroi, Yukiko; Potenzieri, Carl; Undem, Blair E.; Gao, Peisong; Han, Liang; Canning, Brendan J.

    2016-01-01

    The effect of respiratory tract viral infection on evoked cough in guinea pigs was evaluated. Guinea pigs were inoculated intranasally with either parainfluenza type 3 (PIV3) and cough was quantified in conscious animals. The guinea pigs infected with PIV3 (day 4) coughed nearly three times more than those treated with the viral growth medium in response to capsaicin, citric acid, and bradykinin. Since capsaicin, citric acid, and bradykinin evoked coughing in guinea pigs can be inhibited by drugs that antagonize the transient receptor potential cation channel, subfamily V, member 1 (TRPV1), it was reasoned that the virally-induced hypertussive state may involve alterations in TPRV1 activity. PIV3 infection caused a phenotypic switch in tracheal nodose Aδ “cough receptors” such that nearly 50% of neurons began to express, de novo, TRPV1 mRNA. There was also an increase TRPV1 expression in jugular C-fiber neurons as determined by qPCR. It has previously been reported that tracheal-specific nodose neurons express the BDNF receptor TrkB and jugular neurons express the NGF receptor TrkA. Jugular neurons also express the artemin receptor GFRα3. All these neurotrophic factors have been associated with increases in TRPV1 expression. In an ex vivo perfused guinea pig tracheal preparation, we demonstrated that within 8 h of PIV3 infusion there was no change in NGF mRNA expression, but there was nearly a 10-fold increase in BDNF mRNA in the tissue, and a small but significant elevation in the expression of artemin mRNA. In summary, PIV3 infection leads to elevations in TRPV1 expression in the two key cough evoking nerve subtypes in the guinea pig trachea, and this is associated with a hypertussive state with respect to various TRPV1 activating stimuli. PMID:27213574

  10. Experimental congenital syphilis: guinea pig model.

    PubMed Central

    Wicher, K; Baughn, R E; Wicher, V; Nakeeb, S

    1992-01-01

    Neonates born to female guinea pigs of either a highly susceptible (C4D) or a resistant (Albany) strain, infected prior to or during pregnancy with a single dose of Treponema pallidum, showed in their sera from the first day of life immunoglobulin M (IgM) antibodies to T. pallidum, circulating immune complexes consisting of IgM antibodies and treponemal antigens, and IgM rheumatoid factor. Although the animals were asymptomatic for a 6-month observation period, several lines of evidence indicated that they were infected in utero. Molecular analysis of whole sera, purified serum IgM fraction, or dissociated immune complexes demonstrated IgM reactivity against one (47 kDa) or more of several T. pallidum peptides (15, 17, 37, 42, 45, and 87 kDa) recognized as integral membrane components. Sequential analysis of the neonates' sera by immunoblot and enzyme-linked immunosorbent assay, using alcohol-treated T. pallidum, T. phagedenis biotype Reiter, and T. vincentii, demonstrated early IgM antibodies followed 3 to 4 months later by IgG2- and IgG1-specific antibodies to T. pallidum. Moreover, an infectivity test done in five rabbits with pooled tissue extracts prepared from liveborn or stillborn animals evoked a seroconversion in two rabbits (reactive Venereal Disease Research Laboratory and fluorescent treponemal antibody tests), suggesting the presence of T. pallidum in the organs. Sera from neonates born to either T. phagedenis biotype Reiter-injected mothers or three normal pregnant females were all serologically negative. The model offers new possibilities for exploration of factors responsible for asymptomatic infection often observed in human congenital syphilis. Images PMID:1729190

  11. Regeneration of guinea PIG facial nerve: the effect of hypergravity

    NASA Astrophysics Data System (ADS)

    Rosenzweig, E.; Horodiceanu, E.; Ishay, J. S.

    Exposure to moderate hypergravity improves the regenerative capacity of sectioned guinea-pig facial nerve. The improvement in regeneration is tri-directional as follows: a) an average 1.7 fold increase in rate of regeneration in guinea pigs subjected to hypergravity; b) a 25% enhancement of facial muscle activity following the exposure to hypergravity; and c) improvement in the quality of regeneration from an esthetic standpoint. A good correlation was recorded between the histological structure of the severed nerve at the end of the regeneration and the clinical results.

  12. Arginase inhibition prevents inflammation and remodeling in a guinea pig model of chronic obstructive pulmonary disease.

    PubMed

    Pera, T; Zuidhof, A B; Smit, M; Menzen, M H; Klein, T; Flik, G; Zaagsma, J; Meurs, H; Maarsingh, H

    2014-05-01

    Airway inflammation and remodeling are major features of chronic obstructive pulmonary disease (COPD), whereas pulmonary hypertension is a common comorbidity associated with a poor disease prognosis. Recent studies in animal models have indicated that increased arginase activity contributes to features of asthma, including allergen-induced airway eosinophilia and mucus hypersecretion. Although cigarette smoke and lipopolysaccharide (LPS), major risk factors for COPD, may increase arginase expression, the role of arginase in COPD is unknown. This study aimed to investigate the role of arginase in pulmonary inflammation and remodeling using an animal model of COPD. Guinea pigs were instilled intranasally with LPS or saline twice weekly for 12 weeks and pretreated by inhalation of the arginase inhibitor 2(S)-amino-6-boronohexanoic acid (ABH) or vehicle. Repeated LPS exposure increased lung arginase activity, resulting in increased l-ornithine/l-arginine and l-ornithine/l-citrulline ratios. Both ratios were reversed by ABH. ABH inhibited the LPS-induced increases in pulmonary IL-8, neutrophils, and goblet cells as well as airway fibrosis. Remarkably, LPS-induced right ventricular hypertrophy, indicative of pulmonary hypertension, was prevented by ABH. Strong correlations were found between arginase activity and inflammation, airway remodeling, and right ventricular hypertrophy. Increased arginase activity contributes to pulmonary inflammation, airway remodeling, and right ventricular hypertrophy in a guinea pig model of COPD, indicating therapeutic potential for arginase inhibitors in this disease. PMID:24563530

  13. Improved Method for Culturing Guinea-Pig Macrophage Cells

    NASA Technical Reports Server (NTRS)

    Savage, J.

    1982-01-01

    Proper nutrients and periodic changes in culture medium maintain cell viability for a longer period. New method uses a thioglycolate solution, instead of mineral oil, to induce macrophage cells in guinea pigs and also uses an increased percent of fetal-calf bovine serum in cultivation medium. Macrophage cells play significant roles in the body's healing and defense systems.

  14. 9 CFR 113.38 - Guinea pig safety test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Guinea pig safety test. 113.38 Section 113.38 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD...

  15. Guinea pig ductus arteriosus. II - Irreversible closure after birth.

    NASA Technical Reports Server (NTRS)

    Fay, F. S.; Cooke, P. H.

    1972-01-01

    To investigate the mechanism underlying irreversibility of ductal closure after birth, studies were undertaken to determine the exact time course for the onset of irreversible closure of the guinea pig ductus arteriosus. Parallel studies of the reactivity of ductal smooth muscle to oxygen and studies of the postpartum cellular changes within the vessel were also carried out.

  16. Reflections on the Fiftieth Reunion of the Guinea Pigs.

    ERIC Educational Resources Information Center

    Loud, Oliver

    1988-01-01

    A member of the original faculty of the experimental Ohio State University Laboratory High School reflects at a fiftieth reunion of the first graduating class. Students were used as guinea pigs to determine the effects of providing teenagers with liberating, interesting, and customized education from university faculty. (SM)

  17. 9 CFR 113.38 - Guinea pig safety test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Guinea pig safety test. 113.38 Section 113.38 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD...

  18. Ototoxic drugs: difference in sensitivity between mice and guinea pigs.

    PubMed

    Poirrier, A L; Van den Ackerveken, P; Kim, T S; Vandenbosch, R; Nguyen, L; Lefebvre, P P; Malgrange, B

    2010-03-01

    The development of experimental animal models has played an invaluable role in understanding the mechanisms of neurosensory deafness and in devising effective treatments. The purpose of this study was to develop an adult mouse model of ototoxic drug-induced hearing loss and to compare the ototoxicity in the adult mouse to that in the well-described guinea pig model. Mice are a powerful model organism, especially due to the large availability of antibodies, probes and genetic mutants. In this study, mice (n=114) and guinea pigs (n=35) underwent systemic treatment with either kanamycin or cisplatin. Auditory brainstem responses showed a significant threshold shift in guinea pigs 2 weeks after the beginning of the ototoxic treatment, while there was no significant hearing impairment recorded in mice. Hair cells and neuronal loss were correlated with hearing function in both guinea pigs and mice. These results indicate that the mouse is not a good model for ototoxicity, which should be taken into consideration in all further investigations concerning ototoxicity-induced hearing loss. PMID:20015469

  19. NASAL LAVAGE ANTIOXIDANTS IN GUINEA PIGS, RATS AND MICE

    EPA Science Inventory

    A new nasal lavage technique was used to compare the washout curves and total lavagable amounts (per kg body wt) of protein, ascorbate, glutathione and uric acid in guinea pigs, rats and mice. Washout curves were usually observed with sequential lavage volumes of saline of 1.0 ml...

  20. Course of coccidioidomycosis in intratracheally infected guinea pigs.

    PubMed Central

    Cox, R A; Pavey, E F; Mead, C G

    1981-01-01

    Two hundred Hartley-inbred guinea pigs were infected intratracheally with 50 viable arthrospores of Coccidioides immitis. At weeks 1 through 10 postinfection, groups of 20 guinea pigs were assayed for skin test, macrophage migration inhibitory factor (MIF), and lymphocyte transformation (LT) responses to coccidioidin. Forty-eight hours after skin testing and just before MIF and LT assays, blood was obtained for complement-fixing (CF) antibody titers and the animals were autopsied to assess the extent of fungal dissemination. Immunological assays established that skin tests and MIF responses converted within 3 weeks of infection. LT responses were not demonstrable until week 5. Dissemination of C. immitis to the liver or spleen was an early event, with 21% of guinea pigs positive by week 2 and 70% positive by week 5. CF antibody titers were demonstrable at week 5, increased logarithmically through week 7, then increased at a slower rate thereafter. Concomitant with the decreased rate of antibody production, guinea pigs began to clear C. immitis from their extrapulmonary tissues. Skin test responses peaked at 6 weeks postinfection when CF antibody titers were less than or equal to 1:16 and then plateaued with increased CF titers. Although this overall immunological profile is consistent with the disease in humans, there was not a direct correlation between CF antibody titer and dissemination to the liver or spleen, nor was there an inverse correlation between CF antibody titers and skin test or MIF responses. Rather, CF antibody titers and cell-mediated immune responses were equally demonstrable in guinea pigs with disseminated or nondisseminated disease. PMID:7216468

  1. Alpha1-adrenoceptors in the guinea pig thoracic aorta.

    PubMed

    Yamamoto, Y; Koike, K

    1999-01-01

    In the present study, we tried to determine which alpha1-adrenoceptor subtypes are involved in the guinea pig thoracic aorta by using in vitro functional analysis. In first, we tried to estimate the pA2 values of some key alpha1-adrenoceptor antagonists (prazosin, 5-methylurapidil, WB4101, BMY7378 and tamsulosin) against responses to norepinephrine in the thoracic aorta of guinea pigs. The concentration-response curves of norepinephrine were rightward shifted by the presence of prazosin, 5 methylurapidil, WB4101, BMY7378 and tamsulosin. The pA2 values for these antagonists against norepinephrine were 7.83, 7.78, 8.20, 5.73 and 9.57, respectively. In second, we tried to compare the estimated pA2 values obtained in the present study with reported pKi and pA2 values for cloned and native alpha1-adrenoceptor subtypes. In rabbit mesenteric artery, trigone, urethra, prostate and human lower urinary tract which were proposed to contain the putative alpha1L-adenoceptor, we obtained the good correlation for the pA2 values reported in these tissues with pA2 values estimated in guinea pig thoracic aorta. Moreover, regression lines were close to the line of identity. These results suggest that the alpha1-adenoceptors mediating contraction of guinea pig thoracic aorta are similar pharmacologically to the putative alpha1L-adenoceptor subtype in rabbit mesenteric artery, trigone, urethra, prostate and human lower urinary tract. As a final point, guinea pig thoracic aorta may be able to use as a tool to develop the new alpha1-adrenoceptor antagonist which is therapeutically advantageous in the treatment of urinary tract obstruction (e. g., in benign prostatic hyperplasia). PMID:10733154

  2. Gallbladder motility and the sex of the guinea pig.

    PubMed

    Kline, Loren; Karpinski, Edward

    2016-06-01

    Progesterone (P), 17β-estradiol (E2), and dihydrotestosterone (DHT) affect gallbladder motility. When gallbladders were taken from women and men, women had more estrogen and P receptors than men. Both P and E2 had an inhibitory effect upon gallbladder contractility in men and premenopausal and postmenopausal women. Similar findings have been reported in gallbladder strips from male and female guinea pigs. In the present study, there was no significant difference in the amount of E2-, P-, or DHT-induced relaxation of CCK-induced tension when the responses in gallbladder strips from male and female guinea pigs were compared. Three metabolites of P were used: 17-hydroxyprogesterone (17-P), 20α-hydroxyprogesterone (20-P), and 21-hydroxyprogesterone (21-P). There was no significant difference in the responses from strips from male and female guinea pigs. In order to determine if the effects of E2 and P were additive, strips from male animals were exposed to either E2 or P and the amount of relaxation recorded. After recovery, the strips were exposed to E2 or P in reverse order to ensure the order of treatment had no effect. Then, the strips were treated with both E2 and P simultaneously and the relaxation recorded. This procedure was repeated with strips from female guinea pigs. The effect of E2 and P was found to be additive; however, the response of the strips from each sex were not significantly different. It is concluded that the sex of the guinea pig has no significant effect on the response to the sex hormones used. PMID:27354545

  3. 9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary... pigs or hamsters contained therein; (3) the inner surfaces of corrugated fiberboard, cardboard,...

  4. Effect of Hypergravity Stress on Gaseous Exchange and Survival of Young and Old Guinea Pigs

    NASA Astrophysics Data System (ADS)

    Muradian, Kh. K.; Timchenko, A. N.

    Hypergravity tolerance decreases in aging Guinea pigs, the range being lower than in other studied species of laboratory mammals - mice, hamsters, and rats. Moreover, for the gaseous exchange rate and body temperature, the decline during the stress is not characteristic for Guinea pigs of both age groups, in contrast to other species. In general, hypergravity tolerance of Guinea pigs could be more appropriate experimental models.

  5. Mammary gland tumors in irradiated and untreated guinea pigs

    SciTech Connect

    Hoch-Ligeti, C.; Liebelt, A.G.; Congdon, C.C.; Stewart, H.L.

    1986-01-01

    This is a report of mammary gland tumors from 62 guinea pigs. The tumors arose in the terminal ductal-lobular units as either lobular acinar carcinoma or cystadenocarcinoma or as papillary carcinomas within large ducts near the mammilla. About half the number of the males had terminal ductal-lobular carcinomas and all but 2 of the papillary duct carcinomas also arose in males. Large tumors frequently exhibited squamous, chondromatous, osseous, fatty and myoepitheliomatous types of tissues. In 2 irradiated males and 1 female the tumors metastasized. Whole-body irradiation did not produce significant changes in the number or sex distribution or in the morphology of mammary gland tumors in inbred or outbred guinea pigs. All females had cystic ovaries without increase in granulosa cells, 24 (66.6%) had uterine tumors and 13 (34.2%) had adrenal gland tumors; all males had atrophic testes, 5 (16.5%) had testicular and 6 (22.2%) had adrenal gland tumors.

  6. Diffuse Infiltrative Gastrointestinal Lipomatosis in a Guinea Pig (Cavia porcellus)

    PubMed Central

    Beninson, Jennifer A; Keller, Jill M; Hoenerhoff, Mark J

    2015-01-01

    An intact adult male guinea pig (Cavia porcellus) went into cardiopulmonary arrest during a surgical procedure, and efforts at resuscitation were unsuccessful. Gross examination revealed a gastric rupture along the greater curvature of the stomach, which was associated with free blood and ingesta in the abdominal cavity, and a 2-cm nodular, partially circumferential, soft-to-firm mass within the pyloric region. Histologically, the pyloric mass was composed of sheets of infiltrative adipocytes expanding the muscular wall. Similar infiltrative sheets of adipocytes were present adjacent to the rupture site and within the small intestine, cecum, and colon. These findings are consistent with diffuse infiltrative lipomatosis, an exceedingly rare condition in human and veterinary species. This report is the first description of this rare disease in guinea pigs, and the concurrent involvement of both the stomach and intestines has not been reported in any veterinary species. PMID:26473346

  7. Suppressed tuberculin reaction in guinea pigs following laser irradiation

    SciTech Connect

    Inoue, K.; Nishioka, J.; Hukuda, S.

    1989-01-01

    Tuberculin reactions were tested at the bilateral sites of the backs of sensitized guinea pigs. Laser irradiation at an energy fluence of 3.6 J at one site of reaction suppressed the reaction not only at the irradiated site but also at the contralateral nonirradiated site. These phenomena were observed when mononuclear cells were dominant in the perivascular cellular infiltration. The results indicate that local irradiation with a low-power laser has systemic inhibitory effects on delayed hypersensitivity reactions.

  8. Acute effects of aflatoxins on guinea pig isolated ileum.

    PubMed

    Luzi, A; Cometa, M F; Palmery, M

    2002-10-01

    Previous studies on the aflatoxins have focused mainly on their chronic toxic effects. In this study we investigated the acute gastrointestinal effects of four common aflatoxins on isolated guinea pig ileum. AFB(1) (EC(50) 4.6+/-0.4 microM) and AFB(2) (EC(50)17+/-4.4 microM) contracted isolated guinea pig ileum in a dose-dependent manner, whereas AFG(1) and AFG(2) evoked no contractions. Atropine (5.9 nM 11.8 and 23.6 nM) antagonized AFB(1)-induced contractions in a dose-dependent manner. Pretreatment with the nicotinic ganglionic blocker, hexamethonium (up to 55 microM), left AFB(1)-induced contractions unchanged. In contrast, tetrodotoxin (0.3 microM), blocked AFB(1) contractile activity. The two inhibitors of ACh release, morphine (0.3 microM) and clonidine (0.4 microM), antagonized EC(50) AFB(1)-induced contractions, and apamin, a drug that increases neuronal excitability, facilitated the EC(50) AFB(1)-induced contractile effect. The choline uptake blocker, hemicholinium (17.4 microM) markedly reduced AFB(1)-induced contractions. These results suggest that aflatoxins induce their contractile effect indirectly through the cholinergic system by stimulating acetylcholine release from the postganglionic parasympathetic nerve endings. The acute actions of aflatoxins on isolated guinea pig ileum could explain their acute gastrointestinal effects in humans and animals. PMID:12206819

  9. Establishment, Culture, and Characterization of Guinea Pig Fetal Fibroblast Cell

    PubMed Central

    Mahboobi, Reza; Dianatpour, Mehdi; Zare, Shahrokh; Hosseini, Seyed Ebrahim

    2014-01-01

    Establishment of Guinea pig fetal fibroblast cells and their biological evaluation before and after cryopreservation were the main purposes of this study. After determination of the proper age of pregnancy by ultrasonography, 30 days old fetuses of Guinea pigs were recovered. Their skins were cut into small pieces (1 mm2) and were cultured. When reaching 80–90% confluence, the cells were passaged. Cells of the second and eighth passages were cultured in 24-well plates (4 × 104 cells/well) for 6 days and three wells per day were counted. The average cell counts at each time point were then plotted against time and the population doubling time (PDT) was determined. Then, vials of cells (2 × 106 cells/mL) were cryopreserved for 1 month and after thawing, the cell viability was evaluated. The PDT of the second passage was about 23 h and for the eighth passage was about 30 h. The viability of the cultures was 95% in the second passage and 74.5% in the eighth passage. It was shown that the Guinea pig fetal fibroblast cell culture can be established using the adherent culture method while, after freezing, the viability indices of these cells were favorable. PMID:24790770

  10. Pathogenesis of Bolivian Hemorrhagic Fever in Guinea Pigs.

    PubMed

    Bell, T M; Bunton, T E; Shaia, C I; Raymond, J W; Honnold, S P; Donnelly, G C; Shamblin, J D; Wilkinson, E R; Cashman, K A

    2016-01-01

    Machupo virus, the cause of Bolivian hemorrhagic fever, is a highly lethal viral hemorrhagic fever with no Food and Drug Administration-approved vaccines or therapeutics. This study evaluated the guinea pig as a model using the Machupo virus-Chicava strain administered via aerosol challenge. Guinea pigs (Cavia porcellus) were serially sampled to evaluate the temporal progression of infection, gross and histologic lesions, and sequential changes in serum chemistry and hematology. The incubation period was 5 to 12 days, and complete blood counts revealed leukopenia with lymphopenia and thrombocytopenia. Gross pathologic findings included congestion and hemorrhage of the gastrointestinal mucosa and serosa, noncollapsing lungs with fluid exudation, enlarged lymph nodes, and progressive pallor and friability of the liver. Histologic lesions consisted of foci of degeneration and cell death in the haired skin, liver, pancreas, adrenal glands, lymph nodes, tongue, esophagus, salivary glands, renal pelvis, small intestine, and large intestine. Lymphohistiocytic interstitial pneumonia was also present. Inflammation within the central nervous system, interpreted as nonsuppurative encephalitis, was histologically apparent approximately 16 days postexposure and was generally progressive. Macrophages in the tracheobronchial lymph node, on day 5 postexposure, were the first cells to demonstrate visible viral antigen. Viral antigen was detected throughout the lymphoid system by day 9 postexposure, followed by prominent spread within epithelial tissues and then brain. This study provides insight into the course of Machupo virus infection and supports the utility of guinea pigs as an additional animal model for vaccine and therapeutic development. PMID:26139838

  11. Novel antitussive effect of suplatast tosilate in guinea pigs.

    PubMed

    Zhou, Jian-Rong; Syono, Ryo-ichi; Fukumi, Syu-ichi; Kimoto, Kenji; Shirasaki, Tetsuya; Soeda, Fumio; Takahama, Kazuo

    2015-01-01

    We studied the antitussive effects of suplatast, a Th2 cytokine inhibitor, and compared them with the effects of codeine using an experimental cough model in guinea pigs. Suplatast and codeine dose-dependently inhibited cough caused by mechanical stimulation of the larynx, but they did not inhibit cough caused by mechanical stimulation of the bifurcation of the trachea. In guinea pigs with bronchitis, suplatast had an antitussive effect on cough caused by stimulation of the larynx, whereas codeine did not inhibit such cough. In SO2-exposed guinea pigs, suplatast tended to inhibit cough caused by mechanical stimulation of the tracheal bifurcation. Further, suplatast inhibited citric acid-induced cough augmented by pretreatment with an angiotensin-converting enzyme inhibitor, whereas codeine did not inhibit such cough. Suplatast also inhibited bradykinin-induced discharges of airway vagal afferent nerves and significantly inhibited 4-aminopyridine-induced discharges of airway vagal afferent nerves. These findings indicate that the antitussive effects of suplatast are mediated by a novel mechanism involving the peripheral nervous system. PMID:25592147

  12. On the morality of Guinea-pig recruitment.

    PubMed

    Valdman, Mikhail

    2010-07-01

    ABSTRACT Can it be wrong to conduct medical research on human subjects even with their informed consent and even when the transaction between the subjects and researchers is expected to be mutually beneficial? This question is especially pressing today in light of the rise of a semi-professional class of 'guinea pigs'- human research subjects that sell researchers a right of access to their bodies in exchange for money. Can these exchanges be morally problematic even when they are consensual and mutually beneficial? I argue that there are two general kinds of concern one can have about such transactions - concerns about the nature of what is sold and concerns about the conditions in which the selling occurs. The former involves worries about degradation and the possible wrongness of selling a right of access to one's body. These worries, I argue, are not very serious. The latter involves worries about coercion, exploitation, and undue influence - about how, by virtue of their ignorance, impulsiveness, or desperation, guinea pigs can be taken advantage of by medical researchers. These worries are quite serious but I argue that, at least in cases where the exchange between guinea pigs and researchers is consensual and mutually beneficial, they do not raise insurmountable moral problems. PMID:19222441

  13. The purinoceptors of the guinea-pig isolated taenia caeci.

    PubMed

    Piper, A S; Hollingsworth, M

    1995-07-01

    The guinea-pig taenia caeci contains both P1 and P2 purinoceptors mediating relaxation. The P2 purinoceptors have been further characterized using an experimental approach designed to minimise complicating factors. In the presence of the adenosine uptake inhibitor S-(4-nitrobenzyl)-6-thioinosine (NBTI, 300 nM) and a pA100 concentration of the P1 purinoceptor antagonist 8-sulphophenyltheophylline (140 microM), the potency order of agonists was: 2-methylthio-ATP > adenosine 5'-triphosphate (ATP) = alpha, beta-methylene ATP > beta, gamma-methylene ATP > uridine 5'-triphosphate. Suramin antagonized ATP (pA2 = 5.52 +/- 0.17, Schild plot slope = 0.67 +/- 0.08) and 2-methylthio-ATP (pA2 = 5.78 +/- 0.30, Schild plot slope = 1.37 +/- 0.39) while responses to 5'-N-ethylcarboxamidoadenosine (NECA) were unaffected. The findings suggest that suramin, while it is selective for P2 relative to P1 purinoceptors, is not a true competitive antagonist. Pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) antagonized ATP in isolated guinea-pig vas deferens, but had no effect on responses to ATP in guinea-pig taenia caeci indicating it is selective for P2X relative to P2Y purinoceptors. PMID:7589176

  14. Studies of guinea pig immunoglobulin isotype, idiotype and antiidiotype

    SciTech Connect

    Tirrell, S.M.

    1988-01-01

    Immunization of Guinea pigs with diphtheria toxoid generated antibodies of the IgG class that were capable of neutralizing native toxin in vivo. Sera from these animals were used to affinity purify idiotypic antibodies (AB1). AB1 vaccines derived from the IgG1 class and from F(ab{prime}){sub 2} of IgG1 + IgG2 (IgG1/2) classes were effective in inducing a syngeneic anti-idiotype (AB2) response. Animals immunized with AB1 consisting of both IgG1/2 did not elicit a detectable AB2 response. Binding of homologous {sup 125}I-F(ab{prime}){sub 2} (AB1) to the antiidiotype was inhibited 90% in the presence of DT.F(ab{prime}){sub 2} derived from preimmune serum or had no inhibitory effects on the idiotype-antiidiotype interactions. Two groups of outbred guinea pigs were vaccinated with alum absorbed F(ab{prime}){sub 2} of anti-idiotype IgG1/2 (AB2). Of the ten animals inoculated with AB2, three tested positive by RIA against {sup 125}I-DT. Two of the RIA positive sera contained antibodies that neutralized diphtheria toxin in a rabbit intracutaneous assay. Purification of guinea pig IgG by protein A-Sepharose affinity chromatography resulted in the separation of three distinct IgG populations.

  15. Antigen-binding small lymphocytes in the guinea-pig

    PubMed Central

    Donald, D.; Beck, J. Swanson

    1974-01-01

    The time course of the relative distribution of small lymphocytes binding 125I-labelled human thyroglobulin (HTg) in cell suspensions from the peripheral blood and various lymphoid organs was studied in guinea-pigs at progressive intervals up to 28 days after immunization with an emulsion of HTg and BCG in Freund's incomplete adjuvant (FIA). Small lymphocytes binding 125I-labelled HTg were first detected in peripheral blood, popliteal (draining) lymph node, spleen and bone marrow preparations on the 10th day, and in mesenteric (distant) lymph node and thymus preparations on the 14th day after primary immunization. In general, the percentage of these cells increased progressively thereafter until the end of the period of study. Blocking experiments with unlabelled antigens indicated that the binding of 125I-labelled HTg by small lymphocytes was specific. An anti-HTg antibody cytophilic for guinea-pig small lymphocytes was demonstrated by the passive transfer of antigen-binding capacity to lymphocytes of unimmunized animals with hyperimmune guinea-pig serum. It is proposed that, in these experiments, anti-HTg cytophilic antibody was bound first to small lymphocytes in the tissues participating actively in the immune response (popliteal node, spleen and bone marrow) before spilling over into the general circulation to coat lymphocytes at other sites (mesenteric node and thymus). PMID:4604111

  16. Organophosphorus Inhibition and Characterization of Recombinant Guinea Pig Acetylcholinesterase.

    PubMed

    Ruark, Christopher D; Chapleau, Richard R; Mahle, Deirdre A; Gearhart, Jeffery M

    2015-01-01

    Organophosphorus (OP) pesticides and nerve agents have been designed to inhibit the hydrolysis of the neurotransmitter acetylcholine by covalently binding to the active site serine of acetylcholinesterase while Alzheimer drugs and prophylactics, such as tacrine, are characterized by reversible binding. Historically, the guinea pig has been believed to be the best non-primate model for OP toxicology and medical countermeasure development because, similarly to humans, guinea pigs have low amounts of circulating OP metabolizing carboxylesterase. To explore the hypothesis that guinea pigs are the appropriate responder species for OP toxicology and medical countermeasure development, guinea pig acetylcholinesterase (gpAChE) was cloned into pENTR/D-TOPO, recombined into pT-Rex-DEST30 and expressed in Human Embryonic Kidney 293 cells. Recombinant gpAChE was purified to a specific activity of 800 U/mg using size exclusion and immobilized nickel affinity chromatography, with purity confirmed by gel electrophoresis. Ellman's assay was used to enzymatically characterize gpAChE, identifying a K(M) of 154±18.7 µmol L(-1) and a k(cat) of 4.79x10(4)±5.26x10(2) /sec. Apparent gpAChE IC50's for diisopropylfluorophosphate, dicrotophos, paraoxon, and an Alzheimer's drug, tacrine, were found to be 10.1±1.98, 337±108, 1.02±0.29 and 0.30±0.01 µmol L(-1), respectively. Apparent gpAChE inhibition constants for diisopropylfluorophosphate, dicrotophos, paraoxon, and tacrine were found to be 8.40±0.60, 4.50±0.30, 0.29±0.01 and 0.42±0.07 µmol L(-1), respectively. Lineweaver-Burk plots confirmed tacrine as a mixed inhibitor and paraoxon, dicrotophos and diisopropylfluorophosphate as irreversible non-competitive inhibitors. gpAChE bimolecular rate constants for diisopropylfluorophosphate, dicrotophos and paraoxon were found to be 1.44±0.33x10(4), 1.56±0.12x10(3) and 4.57± 0.23x10(5) L µmol(-1) min(-1), respectively. Although the blood levels of OP metabolizing carboxylesterases

  17. Renal failure in a guinea pig (Cavia porcellus) following ingestion of oxalate containing plants

    PubMed Central

    Holowaychuk, Marie K.

    2006-01-01

    A 1-year-old guinea pig presented with anorexia, lethargy, and weight loss, 1 week after ingesting a peace lily leaf. Laboratory findings were suggestive of renal failure and included elevated blood urea nitrogen and creatinine with concurrent isosthenuria. The guinea pig was euthanized 1 month later due to worsening clinical signs. PMID:16933558

  18. 9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Primary enclosures used to transport... enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal Welfare regulations shall offer for transportation, or transport, in commerce any live guinea pig or hamster in...

  19. Dioxin in soil: bioavailability after ingestion by rats and guinea pigs

    SciTech Connect

    McConnell, E.E.; Lucier, G.W.; Rumbaugh, R.C.; Albro, P.W.; Harvan, D.J.; Hass, J.R.; Harris, M.W.

    1984-03-09

    Soil environmentally contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was given by gavage to guinea pigs and rats. The development of a characteristic clinicopathologic syndrome in guinea pigs, the induction of aryl hydrocarbon hydroxylase in rats, and the presence of TCDD in the livers of both species show that TCDD in soil exhibits high biological availability after ingestion.

  20. Infection of Guinea Pigs with Vesicular Stomatitis New Jersey Virus Transmitted by Culicoides sonorensis (Diptera: Ceratopogonidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interpretive Biting midges,Culicoides sonorensis were shown to be capable of transmitting vesicular stomatitis New Jersey virus (VSNJV) to guinea pigs. Despite seroconversion for VSNJV, none of the guinea pigs developed clinical signs when infected in the abdomen by either infected insects or by nee...

  1. Molecular cloning and expression of the calmodulin gene from guinea pig hearts

    PubMed Central

    FENG, RUI; LIU, YAN; SUN, XUEFEI; WANG, YAN; HU, HUIYUAN; GUO, FENG; ZHAO, JINSHENG; HAO, LIYING

    2015-01-01

    The aim of the present study was to isolate and characterize a complementary DNA (cDNA) clone encoding the calmodulin (CaM; GenBank accession no. FJ012165) gene from guinea pig hearts. The CaM gene was amplified from cDNA collected from guinea pig hearts and inserted into a pGEM®-T Easy vector. Subsequently, CaM nucleotide and protein sequence similarity analysis was conducted between guinea pigs and other species. In addition, reverse transcription-polymerase chain reaction (RT-PCR) was performed to investigate the CaM 3 expression patterns in different guinea pig tissues. Sequence analysis revealed that the CaM gene isolated from the guinea pig heart had ∼90% sequence identity with the CaM 3 genes in humans, mice and rats. Furthermore, the deduced peptide sequences of CaM 3 in the guinea pig showed 100% homology to the CaM proteins from other species. In addition, the RT-PCR results indicated that CaM 3 was widely and differentially expressed in guinea pigs. In conclusion, the current study provided valuable information with regard to the cloning and expression of CaM 3 in guinea pig hearts. These findings may be helpful for understanding the function of CaM3 and the possible role of CaM3 in cardiovascular diseases. PMID:26136979

  2. Prevention of reoxygenation-induced arrhythmias in guinea pig papillary muscles.

    PubMed

    Hayashi, H; Terada, H; Katoh, H; McDonald, T F

    1996-06-01

    Effects of various agents on reoxygenation-induced arrhythmias, action potentials, and tension of guinea pig papillary muscles were recorded to investigate the site of action. Triggered activities due to delayed afterdepolarizations (DADs) and aftercontractions were elicited on reoxygenation after 60-min substrate-free hypoxia. Low extracellular Ca2+ (0.1 mM) abolished arrhythmias, and high Ca2+ (4.9 mM) increased the amplitudes of DADs and aftercontractions. D-600 at the high concentration (20 microM) decreased the incidence of arrhythmias (p < 0.05 vs. no drug) and decreased the recovery of developed tension after reoxygenation (p < 0.001). Ryanodine (1 microM) abolished aftercontractions and arrhythmias but did not affect the recovery of developed tension. Tetrodotoxin (TTX 3 microM) and nicorandil (100 microM) decreased the incidence of arrhythmias (p < 0.05), but did not affect the recovery of developed tension or the amplitudes of aftercontractions. TTX caused only a slight decrease in Ca2+ transients in a fluo-3-loaded guinea pig ventricular myocyte. The Ca2+ entry through the Ca2+ channels apparently synchronized Ca2+ release from the sarcoplasmic reticulum, and D-600 at the high concentration apparently decreased the incidence of arrhythmias. TTX and nicorandil decreased arrhythmias, probably by decreasing the Na+ current or by increasing the ATP-sensitive K+ current, respectively. PMID:8761848

  3. Multielement residues in tissues of guinea pigs fed sweet clover grown on fly ash.

    PubMed

    Furr, K; Stoewsand, G S; Bache, C A; Gutenmann, W A

    1975-05-01

    Yellow sweet clover (Melilotus officinalis) was harvested from fly ash dumped in a landfill site at Lansing, NY. This clover was chopped, dried, and formulated at 45% into an otherwise purified diet and fed to six guinea pigs for 90 days. Control sweet clover was harvested from gravelly subsoil and processed and fed to another group of guinea pigs for the same period. Samples of fly ash, gravelly subsoil, sweet clover, liver, kidneys, and left-rear gastrocnemius muscle of all guinea pigs were freeze-dried and analyzed for 35 elements by neutron activation analysis. The fly ash contained 28 elements at higher levels than the gravelly subsoil, while the clover harvested from fly ash contained 19 elements in increased amounts over those in the clover harvested from the gravel soil. Growth rate of both groups of guinea pigs was similar. Rubidium and selenium were present at higher levels in the tissues of guinea pigs fed the fly ash clover. PMID:1130838

  4. A First Generation Comparative Chromosome Map between Guinea Pig (Cavia porcellus) and Humans

    PubMed Central

    Romanenko, Svetlana A.; Perelman, Polina L.; Trifonov, Vladimir A.; Serdyukova, Natalia A.; Li, Tangliang; Fu, Beiyuan; O’Brien, Patricia C. M.; Ng, Bee L.; Nie, Wenhui; Liehr, Thomas; Stanyon, Roscoe; Graphodatsky, Alexander S.; Yang, Fengtang

    2015-01-01

    The domesticated guinea pig, Cavia porcellus (Hystricomorpha, Rodentia), is an important laboratory species and a model for a number of human diseases. Nevertheless, genomic tools for this species are lacking; even its karyotype is poorly characterized. The guinea pig belongs to Hystricomorpha, a widespread and important group of rodents; so far the chromosomes of guinea pigs have not been compared with that of other hystricomorph species or with any other mammals. We generated full sets of chromosome-specific painting probes for the guinea pig by flow sorting and microdissection, and for the first time, mapped the chromosomal homologies between guinea pig and human by reciprocal chromosome painting. Our data demonstrate that the guinea pig karyotype has undergone extensive rearrangements: 78 synteny-conserved human autosomal segments were delimited in the guinea pig genome. The high rate of genome evolution in the guinea pig may explain why the HSA7/16 and HSA16/19 associations presumed ancestral for eutherians and the three syntenic associations (HSA1/10, 3/19, and 9/11) considered ancestral for rodents were not found in C. porcellus. The comparative chromosome map presented here is a starting point for further development of physical and genetic maps of the guinea pig as well as an aid for genome assembly assignment to specific chromosomes. Furthermore, the comparative mapping will allow a transfer of gene map data from other species. The probes developed here provide a genomic toolkit, which will make the guinea pig a key species to unravel the evolutionary biology of the Hystricomorph rodents. PMID:26010445

  5. A First Generation Comparative Chromosome Map between Guinea Pig (Cavia porcellus) and Humans.

    PubMed

    Romanenko, Svetlana A; Perelman, Polina L; Trifonov, Vladimir A; Serdyukova, Natalia A; Li, Tangliang; Fu, Beiyuan; O'Brien, Patricia C M; Ng, Bee L; Nie, Wenhui; Liehr, Thomas; Stanyon, Roscoe; Graphodatsky, Alexander S; Yang, Fengtang

    2015-01-01

    The domesticated guinea pig, Cavia porcellus (Hystricomorpha, Rodentia), is an important laboratory species and a model for a number of human diseases. Nevertheless, genomic tools for this species are lacking; even its karyotype is poorly characterized. The guinea pig belongs to Hystricomorpha, a widespread and important group of rodents; so far the chromosomes of guinea pigs have not been compared with that of other hystricomorph species or with any other mammals. We generated full sets of chromosome-specific painting probes for the guinea pig by flow sorting and microdissection, and for the first time, mapped the chromosomal homologies between guinea pig and human by reciprocal chromosome painting. Our data demonstrate that the guinea pig karyotype has undergone extensive rearrangements: 78 synteny-conserved human autosomal segments were delimited in the guinea pig genome. The high rate of genome evolution in the guinea pig may explain why the HSA7/16 and HSA16/19 associations presumed ancestral for eutherians and the three syntenic associations (HSA1/10, 3/19, and 9/11) considered ancestral for rodents were not found in C. porcellus. The comparative chromosome map presented here is a starting point for further development of physical and genetic maps of the guinea pig as well as an aid for genome assembly assignment to specific chromosomes. Furthermore, the comparative mapping will allow a transfer of gene map data from other species. The probes developed here provide a genomic toolkit, which will make the guinea pig a key species to unravel the evolutionary biology of the Hystricomorph rodents. PMID:26010445

  6. Ozone-Induced Hypertussive Responses in Rabbits and Guinea Pigs

    PubMed Central

    Clay, Emlyn; Patacchini, Riccardo; Trevisani, Marcello; Preti, Delia; Branà, Maria Pia; Spina, Domenico

    2016-01-01

    Cough remains a major unmet clinical need, and preclinical animal models are not predictive for new antitussive agents. We have investigated the mechanisms and pharmacological sensitivity of ozone-induced hypertussive responses in rabbits and guinea pigs. Ozone induced a significant increase in cough frequency and a decrease in time to first cough to inhaled citric acid in both conscious guinea pigs and rabbits. This response was inhibited by the established antitussive drugs codeine and levodropropizine. In contrast to the guinea pig, hypertussive responses in the rabbit were not inhibited by bronchodilator drugs (β2 agonists or muscarinic receptor antagonists), suggesting that the observed hypertussive state was not secondary to bronchoconstriction in this species. The ozone-induced hypertussive response in the rabbit was inhibited by chronic pretreatment with capsaicin, suggestive of a sensitization of airway sensory nerve fibers. However, we could find no evidence for a role of TRPA1 in this response, suggesting that ozone was not sensitizing airway sensory nerves via activation of this receptor. Whereas the ozone-induced hypertussive response was accompanied by a significant influx of neutrophils into the airway, the hypertussive response was not inhibited by the anti-inflammatory phosphodiesterase 4 inhibitor roflumilast at a dose that clearly exhibited anti-inflammatory activity. In summary, our results suggest that ozone-induced hypertussive responses to citric acid may provide a useful model for the investigation of novel drugs for the treatment of cough, but some important differences were noted between the two species with respect to sensitivity to bronchodilator drugs. PMID:26837703

  7. Vaccination against bovine herpes mammillitis virus infections in guinea pigs.

    PubMed

    Smee, D F; Leonhardt, J A

    1994-01-01

    Bovine herpes mammillitis virus or bovine herpesvirus type 2 (BHV-2) causes ulcerative lesions on the teats and udders of infected cows. Since no commercial vaccine is available for this disease, we investigated certain experimental BHV-2 vaccines against this virus in infected guinea pigs. Vaginally infected guinea pigs get severe, self-limiting vaginal infections characterized by erythema and swelling and the production of measurable vaginal virus titers. Two vaccine approaches were investigated: vaccination with wild-type (WT) virus by the subcutaneous route, and vaccination either subcutaneously or intravaginally with a thymidine kinase (TK) deficient (TK-) virus. The TK- strain was prepared by passage of BHV-2 in the presence of the potent TK-dependent antiviral agent 1-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-5-methyluracil (FMAU). The antiviral activity of FMAU against the virus in plaque reduction assays changed from 0.05 to 2 microM at the same time that the TK activity of the mutant virus decrease to 7% of WT virus TK activity. Subcutaneous vaccination of guinea pigs with WT and TK- viruses did not induce vaginal infection. Primary vaginal infection (vaccination) with the TK- virus led to greatly reduced lesion severity compared to vaginal infection with the WT virus. However, the amount of vaginal virus titers recovered during these primary infections was similar for both TK- and WT viruses, indicating that both viruses had equal infecting potential. Thirty days after vaccination the animals were re-infected intravaginally with WT virus. The vaccinated animals showed dramatically reduced lesion severity and low recoverable virus titers compared to age-matched nonvaccinated animals.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7928285

  8. Ozone-Induced Hypertussive Responses in Rabbits and Guinea Pigs.

    PubMed

    Clay, Emlyn; Patacchini, Riccardo; Trevisani, Marcello; Preti, Delia; Branà, Maria Pia; Spina, Domenico; Page, Clive

    2016-04-01

    Cough remains a major unmet clinical need, and preclinical animal models are not predictive for new antitussive agents. We have investigated the mechanisms and pharmacological sensitivity of ozone-induced hypertussive responses in rabbits and guinea pigs. Ozone induced a significant increase in cough frequency and a decrease in time to first cough to inhaled citric acid in both conscious guinea pigs and rabbits. This response was inhibited by the established antitussive drugs codeine and levodropropizine. In contrast to the guinea pig, hypertussive responses in the rabbit were not inhibited by bronchodilator drugs (β2 agonists or muscarinic receptor antagonists), suggesting that the observed hypertussive state was not secondary to bronchoconstriction in this species. The ozone-induced hypertussive response in the rabbit was inhibited by chronic pretreatment with capsaicin, suggestive of a sensitization of airway sensory nerve fibers. However, we could find no evidence for a role of TRPA1 in this response, suggesting that ozone was not sensitizing airway sensory nerves via activation of this receptor. Whereas the ozone-induced hypertussive response was accompanied by a significant influx of neutrophils into the airway, the hypertussive response was not inhibited by the anti-inflammatory phosphodiesterase 4 inhibitor roflumilast at a dose that clearly exhibited anti-inflammatory activity. In summary, our results suggest that ozone-induced hypertussive responses to citric acid may provide a useful model for the investigation of novel drugs for the treatment of cough, but some important differences were noted between the two species with respect to sensitivity to bronchodilator drugs. PMID:26837703

  9. Formation of slow-reacting substance by guinea pig immunoglobulins.

    PubMed Central

    Jancar, S.; Akimura, O. K.; Dias da Silva, W.

    1976-01-01

    The capacity of guinea pig antibodies to mediate the antigen-induced release of slow-reacting substance (SRS) in the rat peritoneal cavity is restricted to IgG2 and, to a lesser extent, to IgG1 populations of immunoglobulin. IgM and homocytotropic antibody of the reaginic type lacked this activity. The process was partially blocked by previous decomplementation of the rats, was not affected by previous reduction of the circulating leukocytes, and was partially suppressed by previous depletion of circulating platelets with an antiserum to rat platelets. PMID:11696

  10. Common Emergencies in Rabbits, Guinea Pigs, and Chinchillas.

    PubMed

    DeCubellis, Julie

    2016-05-01

    Rabbits, guinea pigs, and chinchillas are some of the more common exotic pets seen in emergency clinics. They frequently present with acute illnesses that are the result of several chronic conditions, most related to inadequate diet and husbandry. This article reviews the diagnosis and treatment of some of the more common acute illnesses. It also discusses the predisposing factors that culminate in acute presentations, so that emergency providers can recognize and be mindful of underlying causes of disease before treatment of acute illnesses. PMID:26948264

  11. Anatomy and Disorders of the Oral Cavity of Guinea Pigs.

    PubMed

    Legendre, Loic

    2016-09-01

    Acquired dental disease represents the most common oral disorder of guinea pigs. Most patients are presented with nonspecific clinical signs and symptoms, such as weight loss, reduced food intake, difficulty chewing and/or swallowing. The physical examination must be followed by standard radiography and/or computed tomography, and thorough inspection under general anesthesia. Several complications may follow, including periodontal disease, subluxation of the temporomandibular joint, periapical infection, and abscessation. The dental treatment is aimed to restore the proper length and shape of both the incisor and cheek teeth, associated with medical and supportive treatment. Abscesses should be surgically addressed by complete excision. PMID:27497208

  12. Biochemical properties of the bromodeoxyuridine-induced guinea pig virus.

    PubMed

    Michalides, R; Schlom, J; Dahlberg, J; Perk, K

    1975-10-01

    The biophysical and biochemical properties of the virus particles released by guinea pig embryo cells treated with 5-bromo-2'-deoxyuridine (BUdR) have been compared to those of the B-type mouse mammary tumor virus (MMTV) and the C-type Rauscher murine leukemia virus. The high-molecular-weight (60 to 70S) RNA of the BUdR-induced guinea pig virus (GPV) has a molecular weight of 8 X 106 when measred by mixed agarose polyacylamide gel electrophoresis. The virus particles isolated from the tissue culture medium of BUdR-induced guniea pig cells have the following properties in common with MMTV: (i) a buoyant density of 1.18 g/ml in sucrose and 1.21 g/ml in CsCl, and (ii) a DNA polymerase that prefers Mg2+ over Mn2+ in an assay using the synthetic template poly(rC):oligo(dG). No nucleic acid sequence homology between GPV RNA and the viral RNAs of the MMTV, murine leukemia virus, hamster sarcoma virus, or Mason-Pfizer monkey virus could be observed in a competition hybridization assay using the radioactive-labeled GPV 60 to 70S RNA. By this same competition by hybridization assay the frequency of GPV proviral sequences was estimated to be at least 83 per haploid cellular genome of guniea pig cells. No nucleic acid sequences related to be GPV RNA were detected in the DNA of normal tissues of mice, rats, cats, dogs, baboons, or humans by direct RNA-DNA hybridization using radioactive GPV60 to 70S RNA. PMID:51933

  13. Differential regulation by a peroxisome proliferator of the different multifunctional proteins in guinea pig: cDNA cloning of the guinea pig D-specific multifunctional protein 2.

    PubMed Central

    Caira, F; Clémencet, M C; Cherkaoui-Malki, M; Dieuaide-Noubhani, M; Pacot, C; Van Veldhoven, P P; Latruffe, N

    1998-01-01

    After our previous report on the cloning of two cDNA species in guinea pig, both encoding the same hepatic 79 kDa multifunctional protein 1 (MFP-1) [Caira, Cherkaoui-Malki, Hoefler and Latruffe (1996) FEBS Lett. 378, 57-60], here we report the cloning of a cDNA encoding a second multifunctional peroxisomal protein (MFP-2) in guinea-pig liver. This 2356 nt cDNA encodes a protein of 735 residues (79.7 kDa) whose sequence shows 83% identity with rat MFP-2 [Dieuaide-Noubhani, Novikov, Baumgart, Vanhooren, Fransen, Goethals, Vandekerckhove, Van Veldhoven and Mannaerts (1996) Eur. J. Biochem. 240, 660-666]. In parallel, we studied the effect of ciprofibrate, a hypolipaemic agent also known as peroxisome proliferator in rodent, on the expression of MFP-1 and MFP-2 (2.6 kb) in rats and guinea pigs. By Northern blotting analysis we demonstrated that three MFP-1-related mRNA species are expressed in the guinea-pig liver. The expression of two of them (3.5 and 2.6 kb) is slightly increased by ciprofibrate, whereas the 3.0 kb MFP-1 mRNA is, unlike the rat one, strongly down-regulated in guinea pigs treated with ciprofibrate. In a similar way, the hepatic expression of the guinea-pig 2.6 kb MFP-2 mRNA is also down-regulated in guinea pigs treated with ciprofibrate. These results demonstrate (1) that in contrast with the unique 3.0 kb MFP-1 rat mRNA, at least three hepatic MFP-1-related mRNA species are co-expressed in guinea pig; and (2) that, opposed to the accepted idea of non-responsiveness of the guinea pig to ciprofibrate, this drug affects MFP-1 and MFP-2 gene expression in this species. Also, the mRNA species for acyl-CoA oxidase and thiolase, two other enzymes of the peroxisomal beta-oxidation pathway that are induced severalfold in responsive species are down-regulated in guinea pig. This paper is the first, to our knowledge, reporting the down-regulation of the expression of genes encoding enzymes involved in the peroxisomal beta-oxidation of fatty acids (MFP-1) and

  14. [Studies on coccidiosis in guinea pigs. 2. Epizootiological survey].

    PubMed

    Muto, T; Yusa, T; Sugisaki, M; Tanaka, K; Noguchi, Y; Taguchi, K

    1985-01-01

    An epizootiological survey has been carried out on naturally occurring coccidiosis in Hartley guinea pigs (weight, 250g) purchased by the National Institute of Health, Tokyo during the period 1964 to 1982. Coccidial infections in breeding colonies of guinea pigs were observed very frequently in weaned animals but scarcely in adult and suckling animals. Oocysts of Eimeria caviae were detected in 53.8% of the 7,162 fecal samples collected from transportation boxes and coccidiosis occurred in 39% of the 1,461 dead or culled animals obtained during the routine one week quarantine period. In the period 1964 to 1971, particularly high rates of prevalence of oocysts, between 55-86%, and incidence of coccidiosis, between 55-76%, were observed. These rates were clearly reduced in the period 1972 to 1982, with a lower rate of isolation of oocysts ranging from 14-48% and les than 20% incidence of coccidiosis (except in 1981 and 1982). The monthly fluctuation of occurrence rates of oocysts and clinical coccidiosis differed over the period of study. From 1964 to 1971, the high prevalence of oocysts was consistently observed accompanied by a bimodal pattern of incidence of coccidiosis in April (85%) and October (78%). In the period 1972 to 1982, both parameters showed a single peak, for prevalence of oocysts in June (60.7%) and for incidence of coccidiosis in May (45%). Oocysts in feces disappeared in February and March and coccidiosis occurred irregularly in 1981 and 1982.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3987821

  15. Synaptic localization of. kappa. opioid receptors in guinea pig neostriatum

    SciTech Connect

    Jomary, C.; Beaudet, A. ); Gairin, J.E. )

    1992-01-15

    Distribution of {kappa} opioid receptors was examined by EM radioautography in sections of guinea pig neostriatum with the selective {sup 125}I-labeled dynorphin analog (D-Pro{sup 10})dynorphin-(1-11). Most specifically labeled binding sites were found by probability circle analysis to be associated with neuronal membrane appositions. Because of limitations in resolution of the method, the radioactive sources could not be ascribed directly to either one of the apposed plasma membranes. Nevertheless, three lines of evidence favored a predominant association of ligand with dendrites of intrinsic striatal neurons: (1) the high frequency with which labeled interfaces implicated a dendrite, (2) the enrichment of dendrodendritic interfaces, and (3) the occurrence of dendritic profiles labeled at several contact points along their plasma membranes. A small proportion of labeled sites was associated with axo-axonic interfaces, which may subserve the {kappa} opioid-induced regulation of presynaptic dopamine and acetylcholine release documented in guinea pig neostriatum. These results support the hypothesis that in mammalian brain {kappa} opioid receptors are conformationally and functionally distinct from {mu} and {delta} types.

  16. Distribution of cholinergic cells in guinea pig brainstem

    PubMed Central

    Motts, S.D.; Slusarczyk, A.S.; Sowick, C.S.; Schofield, B.R.

    2008-01-01

    We used an antibody to choline acetyltransferase (ChAT) to label cholinergic cells in guinea pig brainstem. ChAT-immunoreactive (ChAT-IR) cells comprise several prominent groups, including the pedunculopontine tegmental nucleus, laterodorsal tegmental nucleus, and parabigeminal nucleus, as well as the cranial nerve somatic motor and parasympathetic nuclei. Additional concentrations are present in the parabrachial nuclei and superior colliculus. Among auditory nuclei, the majority of ChAT-IR cells are in the superior olive, particularly in and around the lateral superior olive, the ventral nucleus of the trapezoid body and the superior paraolivary nucleus. A discrete group of ChAT-IR cells is located in the sagulum, and additional cells are scattered in the nucleus of the brachium of the inferior colliculus. A group of ChAT-IR cells lies dorsal to the dorsal nucleus of the lateral lemniscus. A few ChAT-IR cells are found in the cochlear nucleus and the ventral nucleus of the lateral lemniscus. The distribution of cholinergic cells in guinea pigs is largely similar to that of other species; differences occur mainly in cell groups that have few ChAT-IR cells. The results provide a basis for further studies to characterize the connections of these cholinergic groups. PMID:18222049

  17. Pulmonary effects of acid sulfate inhalation in the guinea pig

    SciTech Connect

    Silbaugh, S.A.; Mauderly, J.L.; Wolff, R.K.; Carpenter, R.L.; Brownstein, D.G.; Harkema, J.R.; Rothenberg, S.J.

    1982-07-01

    Guinea pigs were exposed by inhalation for 1 to 8 hours to sulfuric acid aerosols of various sizes and concentrations in order to provide quantitative information for standards setting. The effects of sulfuric acid aerosols were examined to determine acute mortality, changes in respiratory function and morphology, response mechanisms, differences in individual sensitivity and changes in airway response to bronchoconstrictors. An aerosol generator for another sulfur-containing pollutant, ammonium bisulfite, was developed for use in animal exposures. Also, lung lesions which simulate human emphysema were produced by intratracheal elastase instillation to investigate a potential impaired animal model for sulfur pollutant exposures. Pulmonary mechanics, lung morphology, and histamine sensitivity data all suggest that the guinea pig reacts to sulfuric acid aerosols with a nearly all-or-none airway constrictive response. Results also indicate that the concentration at which this response occurs is affected by aerosol size, exposure profile and individual animal sensitivity. No acute pulmonary function changes were noted at concentrations below 15 mg/m/sup 3/. The reason for these differences is unknown.

  18. Cutaneous sensitization to some polyisocyanate prepolymers in guinea pigs.

    PubMed

    Zissu, D; Binet, S; Limasset, J C

    1998-11-01

    Isocyanates are used extensively in the polyurethane industry. Pulmonary and dermal sensitization resulting from exposure to diisocyanates has frequently been reported, but the potential effects of polyisocyanates on health are less well known. Thus, since 1978, occupational exposure limits have been established for diisocyanates only. Nevertheless, respiratory diseases and dermatitis have been reported in the polyurethane industry after accidental isocyanate contact during spills or splashes. The aim of this experimental work was to assess the dermal hypersensitivity of guinea pigs to some polyisocyanate prepolymers by means of a well-conducted standard predictive Buehler test. Our results showed that dicyclohexylmethane 4,4'-diisocyanate (HMDI), toluylene 2,4-diisocyanate (TDI), TDI adduct triol, TDI isocyanurate, 1,6-hexamethylene diisocyanate (HDI), HDI isocyanurate, HDI biuret and isophorone diisocyanate (IPDI) induced dermal sensitization while IPDI isocyanurate did not. In conclusion, the dermal hypersensitivity of guinea pigs to some polyisocyanates was similar to those of their corresponding monomers except for IPDI isocyanurate, suggesting that the results from diisocyanate monomers could not be a valuable approach for the detection of the sensitization potency of the corresponding prepolymers. PMID:9840262

  19. Molecular basis of complement C3 deficiency in guinea pigs.

    PubMed Central

    Auerbach, H S; Burger, R; Dodds, A; Colten, H R

    1990-01-01

    In experiments to ascertain the biochemical basis of a genetically determined deficiency of the third component of complement (C3) in guinea pigs, we found that C3-deficient liver and peritoneal macrophages contain C3 messenger RNA of normal size (approximately 5 kb) and amounts, that this mRNA programs synthesis of pro-C3 in oocytes primed with liver RNA and in primary macrophage cultures. In each instance, heterodimeric native C3 protein was secreted with normal kinetics but the C3 protein product of the deficient cells failed to undergo autolytic cleavage and was unusually susceptible to proteolysis. These data and a selective failure of C3 in plasma of deficient animals to incorporate [14C]methylamine suggested either a mutation in primary structure of the C3 protein or a selective defect in co- or postsynthetic processing affecting the thiolester bridge, a structure important for C3 function. A mutation in the primary structure of C3 was ruled out by comparison of direct sequence analysis of C3 cDNA generated from two C3 deficient and two C3 sufficient guinea pig liver libraries. Three base pair differences, none resulting in derived amino acid sequence differences were identified. Finally, restriction fragment length polymorphisms were identified in the C3 gene that are independent of the deficiency phenotype. This marker of the C3 gene permits testing of these hypotheses using molecular biological and classical genetic methods. Images PMID:1973176

  20. Noninvasive detection of airway constriction in awake guinea pigs

    SciTech Connect

    Silbaugh, S.A.; Mauderly, J.L.

    1984-01-01

    Tidal volume measured by the barometric method is very sensitive to increases in compression and expansion of alveolar gas, such as would be expected to occur during airway narrowing or closure. By comparing a barometric method tidal volume signal (VT') with a reference tidal volume (VT) obtained with a head-out pressure plethysmograph, a simple index related to gas compressibility effects was calculated (VT/VT'). Changes in this index were compared with decreases in dynamic compliance (Cdyn) during histamine aerosol challenge of 15 Charles River Hartley guinea pigs. Decreases in VT/VT' occurred during all aerosol challenges and were correlated with decreases in Cdyn. Decreases in VT/VT' were most marked at Cdyn values of less than 50% of base line. At Cdyn of less than 15% of base line, VT' was 3.1-4.8 times the VT reference signal. No increase in total pulmonary resistance was noted, and Cdyn and VT/VT' returned to base line after histamine exposure was stopped. The authors conclude that gas compressibility effects become substantial during histamine-induced airway constriction in the guinea pig and that the VT/VT' ratio appears to provide a simple noninvasive method of detecting these changes.

  1. Biochemical studies on the toxicity of hematite dust. [Guinea pigs

    SciTech Connect

    Das, B.; Khatoon, N.; Srivastava, R.C.; Viswanathan, P.N.; Rahman, Q.

    1983-12-01

    Biochemical alterations in guinea pig lungs caused by hematite dust were followed at 150 days after intratracheal administration of the dust. In vivo dust exposure caused a significant increase in mitochondrial protein content and cytochrome c oxidase activity whereas diaphorase activity remained unaltered. Mitochondria from the exposed animals were apparently in a swollen state and their contraction profile upon the addition of ATP reflected permeability changes. However, in vitro dust caused no significant alterations. Significant increases in glycogen content along with an insignificant decrease in glycogen phosphorylase activity were also observed in hematite-treated guinea pig lungs. Decrease in drug-metabolizing enzymes such as aniline hydroxylase and tyrosine aminotransferase activities were also evident in the post mitochondrial fraction of the siderotic lungs. (/sup 3/H)Leucine-incorporation studies showed increased protein synthesis in the postmitochondrial fraction. Increase in protein synthesis in mitochondria was only marginal whereas in whole homogenate it decreased considerably. Experiments employing dust tagged with radioactive iron indicated the rapid mobilization of iron from lung and its distribution to various organs. The presence of iron-binding protein was confirmed by employing Sephadex gel-filtration techniques.

  2. Spasmolytic effect of traditional herbal formulation on guinea pig ileum

    PubMed Central

    Kumar, Dushyant; Ganguly, Kuntal; Hegde, H. V.; Patil, P. A.; Kholkute, S. D.

    2015-01-01

    Background: The herbal formulation consisting of Andrographis paniculata Nees., Cassia fistula L., Foeniculum vulgare Mill. and Cuminum cyminum L. is widely used by the local traditional practitioners in rural Northern Karnataka for spasmodic abdominal pain. Objective: The present study was undertaken to evaluate safety and spasmolytic effect of poly-herbal formulation. Materials and Methods: Acute toxicity studies were carried out in Swiss mice, as per the Organization for Economic Co-operation and Development (OECD) guidelines. The spasmolytic activity of the formulation was studied in isolated guinea pig ileum model using histamine and acetylcholine as agonists. The data were analyzed by one-way ANOVA, followed by Dunnetts post-hoc test and P ≤ 0.05 was considered as significant. Results: The formulation did not show any adverse toxic effects and found to be safe. It also showed significant (P < 0.05) relaxation in different agonist like histamine and acetylcholine-induced contractions in guinea pig ileum. Conclusion: Antispasmodic activity of the herbal formulation can be attributed to its atropine-like activity. The present findings, therefore, support its utility in spasmodic abdominal pain. PMID:26604555

  3. Transmural distribution of extracellular purines in isolated guinea pig heart.

    PubMed Central

    Zhu, Q Y; Headrick, J P; Berne, R M

    1991-01-01

    The purine adenosine appears to be involved in regulation of coronary vascular tone. Little is known concerning the levels and distribution of adenosine and related purines in the extracellular fluid of the heart. We have measured epicardial and endocardial levels of adenosine, inosine, hypoxanthine, AMP, and IMP in isolated constant flow perfused guinea pig hearts by using a recently developed technique with porous nylon sampling discs. Venous effluent purine levels were also measured. Concentrations of all purines measured, excluding IMP, were significantly higher in endocardial fluid samples than in epicardial fluid samples (P less than 0.05). Conversely, IMP levels were significantly lower in endocardial than in epicardial samples. The magnitude of the endocardial/epicardial ratios for adenosine, inosine, hypoxanthine, AMP, and IMP were approximately 12:1, 4:1, 5:1, 4:1, and 1:2, respectively. To assess cellular damage, lactate dehydrogenase activity was measured in all fluid samples and was not significantly different in endocardial and epicardial fluid. These data support the existence of significant transmural gradients for extracellular purine levels in crystalloid perfused guinea pig hearts. Transmural differences in vasoactive adenosine levels may be partially due to the greater endocardial oxygen consumption and metabolism and may be involved in maintaining relatively high subendocardial blood flows in the face of high intramyocardial pressures. Images PMID:1988961

  4. Pharmacology of Bradykinin-Evoked Coughing in Guinea Pigs.

    PubMed

    Hewitt, Matthew M; Adams, Gregory; Mazzone, Stuart B; Mori, Nanako; Yu, Li; Canning, Brendan J

    2016-06-01

    Bradykinin has been implicated as a mediator of the acute pathophysiological and inflammatory consequences of respiratory tract infections and in exacerbations of chronic diseases such as asthma. Bradykinin may also be a trigger for the coughing associated with these and other conditions. We have thus set out to evaluate the pharmacology of bradykinin-evoked coughing in guinea pigs. When inhaled, bradykinin induced paroxysmal coughing that was abolished by the bradykinin B2 receptor antagonist HOE 140. These cough responses rapidly desensitized, consistent with reports of B2 receptor desensitization. Bradykinin-evoked cough was potentiated by inhibition of both neutral endopeptidase and angiotensin-converting enzyme (with thiorphan and captopril, respectively), but was largely unaffected by muscarinic or thromboxane receptor blockade (atropine and ICI 192605), cyclooxygenase, or nitric oxide synthase inhibition (meclofenamic acid and N(G)-nitro-L-arginine). Calcium influx studies in bronchopulmonary vagal afferent neurons dissociated from vagal sensory ganglia indicated that the tachykinin-containing C-fibers arising from the jugular ganglia mediate bradykinin-evoked coughing. Also implicating the jugular C-fibers was the observation that simultaneous blockade of neurokinin2 (NK2; SR48968) and NK3 (SR142801 or SB223412) receptors nearly abolished the bradykinin-evoked cough responses. The data suggest that bradykinin induces coughing in guinea pigs by activating B2 receptors on bronchopulmonary C-fibers. We speculate that therapeutics targeting the actions of bradykinin may prove useful in the treatment of cough. PMID:27000801

  5. Investigation Into the Humaneness of Slaughter Methods for Guinea Pigs (Cavia porcelus) in the Andean Region.

    PubMed

    Limon, Georgina; Gonzales-Gustavson, Eloy A; Gibson, Troy J

    2016-01-01

    Guinea pigs (Cavia porcelus) are an important source of nonhuman animal protein in the Andean region of South America. Specific guidelines regarding the welfare of guinea pigs before and during slaughter have yet to be developed. This study critically assessed the humaneness of 4 different stunning/slaughter methods for guinea pigs: cervical neck dislocation (n = 60), electrical head-only stunning (n = 83), carbon dioxide (CO2) stunning (n = 21), and penetrating captive bolt (n = 10). Following cervical neck dislocation, 97% of guinea pigs had at least 1 behavioral or cranial/spinal response. Six percent of guinea pigs were classified as mis-stunned after electrical stunning, and 1% were classified as mis-stunned after captive bolt. Increased respiratory effort was observed during CO2 stunning. Apart from this finding, there were no other obvious behavioral responses that could be associated with suffering. Of the methods assessed, captive bolt was deemed the most humane, effective, and practical method of stunning guinea pigs. Cervical neck dislocation should not be recommended as a slaughter method for guinea pigs. PMID:26963642

  6. Investigation Into the Humaneness of Slaughter Methods for Guinea Pigs (Cavia porcelus) in the Andean Region

    PubMed Central

    Limon, Georgina; Gonzales-Gustavson, Eloy A.; Gibson, Troy J.

    2016-01-01

    Guinea pigs (Cavia porcelus) are an important source of nonhuman animal protein in the Andean region of South America. Specific guidelines regarding the welfare of guinea pigs before and during slaughter have yet to be developed. This study critically assessed the humaneness of 4 different stunning/slaughter methods for guinea pigs: cervical neck dislocation (n = 60), electrical head-only stunning (n = 83), carbon dioxide (CO2) stunning (n = 21), and penetrating captive bolt (n = 10). Following cervical neck dislocation, 97% of guinea pigs had at least 1 behavioral or cranial/spinal response. Six percent of guinea pigs were classified as mis-stunned after electrical stunning, and 1% were classified as mis-stunned after captive bolt. Increased respiratory effort was observed during CO2 stunning. Apart from this finding, there were no other obvious behavioral responses that could be associated with suffering. Of the methods assessed, captive bolt was deemed the most humane, effective, and practical method of stunning guinea pigs. Cervical neck dislocation should not be recommended as a slaughter method for guinea pigs. PMID:26963642

  7. Evidence for independent evolution of functional progesterone withdrawal in primates and guinea pigs

    PubMed Central

    Nnamani, Mauris C.; Plaza, Silvia; Romero, Roberto; Wagner, Günter P.

    2013-01-01

    Background and objectives: Cervix remodeling (CRM) is a critical process in preparation for parturition. Early cervix shortening is a powerful clinical predictor of preterm birth, and thus understanding how CRM is regulated is important for the prevention of prematurity. Humans and other primates differ from most other mammals by the maintenance of high levels of systemic progesterone concentrations. Humans have been hypothesized to perform functional progesterone withdrawal (FPW). Guinea pigs are similar to humans in maintaining high-progesterone concentrations through parturition, thus making them a prime model for studying CRM. Here, we analyze the phylogenetic history of FPW and document gene expression in the guinea pig uterine cervix. Methodology: Data on progesterone withdrawal were collected from the literature, and character evolution was analyzed. Uterine cervix samples were collected from non-pregnant, mid-pregnant and late pregnant guinea pigs. RNA was extracted and sequenced. Relative transcript levels were estimated and compared among sample groups. Results: The phylogenetic analysis shows that FPW evolved independently in primates and guinea pigs. The transcriptome data confirms that guinea pigs down-regulate progesterone receptor toward parturition, in contrast to humans. Some of the similarities between human and guinea pig are: down-regulation of estrogen receptor, up-regulation of VCAN and IGFBP4 as well as likely involvement of prostaglandins. Conclusions and implications: (i) FPW in guinea pigs evolved independently from that in primates. (ii) A small set of conserved gene regulatory changes has been detected. PMID:24481205

  8. Glucose oxidation and oxygen consumption of isolated guinea pig and muskrat hearts.

    PubMed

    McKean, T A

    1987-01-01

    Glucose in Krebs-Henseleit buffer was presented to isolated Langendorff perfused muskrat and guinea pig hearts that were paced at 240 beats/min. Glucose uptake (amount removed from the perfusion fluid) was 3 times greater in the muskrat hearts than in the guinea pig heart. Glucose oxidation (amount converted to CO2) and oxygen consumption did not differ in the hearts of the two species. When glucose is the only exogenous substrate, isolated muskrat hearts extract more glucose than guinea pig hearts but oxidize similar amounts of glucose and have a similar myocardial oxygen consumption. PMID:2881679

  9. Hematological assessment in pet guinea pigs (Cavia porcellus): blood sample collection and blood cell identification.

    PubMed

    Zimmerman, Kurt; Moore, David M; Smith, Stephen A

    2015-01-01

    Pet guinea pigs are presented to veterinary clinics for routine care and treatment of clinical diseases. In addition to obtaining clinical history and exam findings, diagnostic testing may be required, including hematological assessments. This article describes common blood collection methods, including venipuncture sites, the volume of blood that can be safely collected, and handling of the blood. Hematological parameters for normal guinea pigs are provided for comparison with in-house or commercial test results. A description of the morphology of guinea pig leukocytes is provided to assist in performing a differential count. PMID:25421024

  10. Leukotriene B4 receptors on guinea pig alveolar eosinophils

    SciTech Connect

    Maghni, K.; de Brum-Fernandes, A.J.; Foeldes-Filep, E.G.; Gaudry, M.; Borgeat, P.; Sirois, P. )

    1991-09-01

    The existence of receptors for LTB4 on highly purified guinea pig alveolar eosinophils was investigated. Massive infiltration of eosinophils in alveolar spaces was induced in guinea pigs by i.v. injections of Sephadex beads G50 (16 mg/kg). Alveolar eosinophils (50 {times} 10(6) cells) were purified to approximately 98% by Percoll continuous density gradient centrifugation. The binding studies indicated that alveolar eosinophils bind LTB4 in a saturable, reversible and specific manner. Scatchard analysis indicated the existence of high-affinity binding sites (Kd1 = 1.00 {plus minus} 0.22 nM; Bmax1 = 966 {plus minus} 266 sites/cell) and low-affinity binding sites (Kd2 = 62.5 {plus minus} 8.9 nM; Bmax2 = 5557 {plus minus} 757 sites/cell). The metabolism of LTB4 by alveolar eosinophils in binding conditions was assessed by RP-HPLC and no significant degradation of (3H)LTB4 was observed. LTB4 dose-dependently stimulated eosinophil migration in both chemokinesis and chemotaxis assays with an EC50 value of 1.30 {plus minus} 0.14 and 18.14 {plus minus} 1.57 nM, respectively. LTB4 caused a dose-dependent increase in the production of superoxide anion with an apparent EC50 value of 50 {times} 10(-9) M in the authors experimental conditions. LTB4 also induced a dose-dependent increase in the generation of TxA2 with an EC50 value of 46.2 {times} 10(-9) M. Taken together, their results demonstrated that guinea pig alveolar eosinophils express two classes of specific receptors for LTB4. The high-affinity binding sites seem associated to chemokinesis and chemotaxis whereas the low-affinity binding sites seem associated to superoxide anion production and generation of TxA2. The existence of LTB4 receptors in eosinophils could explain the presence of these cells in hypersensitivity reactions.

  11. Citicoline retards myopia progression following form deprivation in guinea pigs.

    PubMed

    Mao, Junfeng; Liu, Shuangzhen; Fu, Chunyan

    2016-06-01

    The retinal dopaminergic system is involved in the myopic shift following form deprivation. Citicoline has been demonstrated to stimulate the dopaminergic system in the brain and retina. Furthermore, citicoline has been used in many neurogenic diseases, such as senile cognitive impairment, stroke and Parkinson's disease as well as in amblyopia and glaucoma. Our aim was to investigate the effect of citicoline on the refractive state and retinal dopamine level in form deprivation myopia of guinea pigs. Guinea pigs, at an age of four weeks, were randomly divided into normal control, deprivation, deprived + citicoline and deprived + vehicle groups. Form deprivation myopia was induced by a translucent eye shield covering the right eye. Citicoline was injected intraperitoneally twice a day (500 mg/kg, 9 am and 9 pm) for 10 days. In vitro, retinal explants were cultured with citicoline for 24 h, with a final citicoline concentration of 100 µmol/L. The ocular refractive parameters and retinal dopamine content were measured. After occlusion for 10 days, the form-deprived eyes became myopic with an increase in axial length and a decrease in retinal dopamine content. The intraperitoneal injection of citicoline reduced the myopic degree (from -3.25 ± 0.77D to -0.62 ± 0.47D, P < 0.001) and partially raised retinal dopamine levels (from 0.55 ± 0.21 ng to 0.81 ± 0.24 ng, P < 0.01) in the form-deprived eyes. After 24 h of culturing retinal explants with citicoline, retinal dopamine content increased significantly (from 0.42 ± 0.14 ng to 0.62 ± 0.21 ng, P < 0.05). These results demonstrated that an intraperitoneal injection of citicoline could retard the myopic shift induced by form deprivation in guinea pigs, which was mediated by an increase in the retinal dopamine levels. PMID:26979720

  12. Assay of contact photosensitivity to musk ambrette in guinea pigs.

    PubMed

    Kochever, I E; Zalar, G L; Einbinder, J; Harber, L C

    1979-08-01

    This study reports the induction of contact photodermatitis to musk ambrette, 2-methoxy-3,5-dinitro-4-methyl-t-butylbenzene, in guinea pigs. Photoallergic contact dermatitis was assayed using 2 alternative induction methods. Successful photosensitization was achieved only when the nuchal skin was stripped with scotch tape before application of musk ambrette and ultraviolet radiation. Induction methods utilizing nonstripped nuchal skin which induce photosensitivity to potent photoallergens were ineffective for musk ambrette. Phtotoxicity tests to musk ambrette at concentrations between 1 and 50% and a dose of 10.2 joules/cm2 from "Black Light" fluorescent tubes were all negative. Under identical irradiation conditions, anthracene at 0.9% and 8-methoxypsoralen at 1% were consistently positive. The mechanism of photosensitivity to musk ambrette appears to be photoallergic rather than phototoxic. The requirement for skin abrasion to induce photosensitization parallels the clinical reports of photosensitivity to musk ambrette in man. PMID:458189

  13. Transmission of Influenza B Viruses in the Guinea Pig

    PubMed Central

    Pica, Natalie; Chou, Yi-Ying; Bouvier, Nicole M.

    2012-01-01

    Epidemic influenza is typically caused by infection with viruses of the A and B types and can result in substantial morbidity and mortality during a given season. Here we demonstrate that influenza B viruses can replicate in the upper respiratory tract of the guinea pig and that viruses of the two main lineages can be transmitted with 100% efficiency between inoculated and naïve animals in both contact and noncontact models. Our results also indicate that, like in the case for influenza A virus, transmission of influenza B viruses is enhanced at colder temperatures, providing an explanation for the seasonality of influenza epidemics in temperate climates. We therefore present, for the first time, a small animal model with which to study the underlying mechanisms of influenza B virus transmission. PMID:22301149

  14. Audiometric effects of simulated sonic booms in guinea pigs

    NASA Astrophysics Data System (ADS)

    Reinis, S.; Weiss, D. S.; Featherstone, J. W.; Tsaros, C.

    1987-03-01

    Changes of hearing thresholds have been studied in guinea pigs following exposure to 100 simulated sonic booms. Simulated sonic booms increased the hearing thresholds at frequencies above 30 kHz. The only early structural change observed was an appearance of a small blood clot in the scala tympani of the basal turn of the cochlea. Although these changes may be specific for small laboratory animals only, they indicate that caution is necessary in exposing people to repeated or intense sonic booms. Also, the data indicate that, following the exposure to the sonic booms, the high frequency hearing is influenced first. Therefore, audiometric testing following the sonic boom exposure should not be limited to the routine audiometric curve ending at 8 kHz.

  15. Infrared neural stimulation: beam path in the guinea pig cochlea

    PubMed Central

    Moreno, Laura E; Rajguru, Suhrud M; Matic, Agnella Izzo; Yerram, Nitin; Robinson, Alan M; Hwang, Margaret; Stock, Stuart; Richter, Claus-Peter

    2011-01-01

    It has been demonstrated INS can be utilized to stimulate spiral ganglion cells in the cochlea. Although neural stimulation can be achieved without direct contact of the radiation source and the tissue, the presence of fluids or bone between the target structure and the radiation source may lead to absorption or scattering of the radiation, which may limit the efficacy of INS. The present study demonstrates the neural structures in the radiation beam path that can be stimulated. Histological reconstructions and microCT of guinea pig cochleae stimulated with an infrared laser suggest that the orientation of the beam from the optical fiber determined the site of stimulation in the cochlea. Best frequencies of the INS-evoked neural responses obtained from the central nucleus of the inferior colliculus matched the histological sites in the spiral ganglion. PMID:21763410

  16. Mycoplasma pneumoniae induces cytotoxic activity in guinea pig bronchoalveolar cells

    SciTech Connect

    Kist, M.; Koester, H.; Bredt, W.

    1985-06-01

    Precultured guinea pig alveolar macrophages (AM) and freshly harvested alveolar cells (FHAC) activated by interaction with Mycoplasma pneumoniae were cytotoxic for xenogeneic /sup 75/selenomethionine-labeled tumor target cells. Phagocytosis of whole opsonized or nonopsonized M. pneumoniae cells was more effective in eliciting cytotoxicity than uptake of sonicated microorganisms. The addition of living mycoplasma cells to the assay system enhanced the cytotoxic effect considerably. Target cells were significantly more susceptible to the cytotoxic action of phagocytes if they were coated with mycoplasma antigen or cocultured together with M. pneumoniae. The activation of the phagocytes could be inhibited by 2-deoxy-D-glucose but not by antimicrobial substances suppressing mycoplasma protein synthesis. It was accompanied by /sup 51/Cr release without detectable signs of cell damage. The supernatants of activated cells were cytotoxic for approximately 24 h. Inhibition, release, and cytotoxic activity indicate the necessity of an intact metabolism of the effector cells and suggest a secretion of cytotoxic substances.

  17. Interactions of trimebutine with guinea-pig opioid receptors.

    PubMed

    Roman, F; Pascaud, X; Taylor, J E; Junien, J L

    1987-05-01

    Affinities of trimebutine (TMB) and N-desmethyl trimebutine (NDTMB) for mu, delta and kappa opioid receptor subtypes have been examined using specific 3H-ligands and guinea-pig membrane. TMB and NDTMB showed a relative higher affinity for the mu receptor subtype although they were, respectively, 30- and 48-fold less active than morphine. The receptor selectivity index for mu, delta and kappa were 100:12:14.4 for TMB, 100:32:25 for NDTMB and 100:5:5 for morphine. The sodium shift ratio was 14 for TMB, 10 for NDTMB and 37 for morphine. These data show that (unlike morphine, a pure mu agonist) TMB and NDTMB can be classified as weak opioid agonists and confirm that peripheral opioid receptors mediate their gastrointestinal motility effects. PMID:2886594

  18. [Scanning electron microscopy study of experimental chorioretinitis in guinea pigs].

    PubMed

    Renard, G; Usui, M; De Kozak, Y; Faure, J P

    1976-04-01

    Retinal lesions are described with the scanning electron microscope in the uveo retinitis induced in guinea pigs by immunization with rod outer segments of bovine retina. The two surfaces in contact of the pigment epithelium and the photoreceptors are separated from each other and observed on flat preparations. On the epithelial side, the evolution of the degenerescence of epithelial cells is observed, from the early disappearance of villosities until the total destruction of the cells. Through lacks in the epithelial layer where the choroid appears, inflammatory cells migrate towards the retina. The impairement of the visual cells is characterized by progressive destruction of outer then inner segments, with preservation of the external limiting membrane. In some areas the degenerative process reaches the layer of visual cells nuclei. Macrophages, and local clusters of lymphocytes are seen in contact with the retinal surface. PMID:135548

  19. SULFAMETHOXAZOLE-TRIMETHOPRIM TREATMENT OF GUINEA PIGS INFECTED WITH 'LEGIONELLA PNEUMPOPHILA'

    EPA Science Inventory

    Legionnaires' disease is a bacterial pneumonia caused by Legionella pneumophila. Many antibiotics inhibit the growth of L. pneumophila in vitro, but only erythromycin and rifampin have been clinically effective. Parallel results have been observed in guinea pigs infected ip with ...

  20. The effect of restraining on the heart rate in guinea pigs

    NASA Technical Reports Server (NTRS)

    Mikiskova, H.

    1980-01-01

    The emotional effect of different applications of electrodes and the fixation for cariographic examination was investigated using guinea pigs. The effect of the stress is discussed in terms of heart rhythm and behavior.

  1. Papular dermatitis induced in guinea pigs by the biting midge Culicoides sonorensis (Diptera: Ceratopogonidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Histological, ultrastructural, and virological examinations were performed on abdominal skin from guinea pigs after a blood meal by colony-bred biting midges, Culicoides sonorensis. Small, superficial, cutaneous, crateriform ulcers with necrosis of superficial dermis developed at feeding sites and ...

  2. Normal behavior and the clinical implications of abnormal behavior in guinea pigs.

    PubMed

    Bradley, T A

    2001-09-01

    Cavies are becoming more popular as pets because they are relatively easy to care for and provide never-ending love and entertainment with their curious but gentle nature. As with other species, the best way to learn about guinea pig behavior is to own guinea pigs. Understanding normal behavior provides the practitioner with the ability to more easily recognize pathology and abnormal behavior. This allows the veterinarian to provide necessary supportive care and pain management more quickly while performing diagnostics and determining the need for therapeutics. Understanding the behavior of cavies allows the clinician to better educate guinea pig-owning clients and to better and more quickly serve the needs of their guinea pig patients. PMID:11601108

  3. Use of guinea pig embryo cell cultures for isolation and propagation of group A coxsackieviruses.

    PubMed Central

    Landry, M L; Madore, H P; Fong, C K; Hsiung, G D

    1981-01-01

    The isolation of group A coxsackieviruses from clinical specimens generally requires the use of suckling mice. By using guinea pig embryo cells, the following coxsackieviruses were isolated from throat swabs and stool samples obtained from patients with a variety of illnesses: two of type A2, one each of types A6 and A8, and four of type 10. Distinct cytopathic effects were produced in 3 to 5 days in the guinea pig embryo cells inoculated with the clinical specimens. In addition, a number of prototype group A coxsackieviruses, including types 2--6, 8, 10, and 12, were readily propagated in guinea pig embryo cell cultures. Thus, guinea pig embryo cells appeared to be a sensitive alternative cell culture system for the isolation and propagation of certain types of group A coxsackieviruses. Images PMID:6263943

  4. Chronic estrogen exposure maintains elevated levels of progesterone receptor mRNA in guinea pig hypothalamus.

    PubMed

    Bayliss, D A; Millhorn, D E

    1991-05-01

    We performed in situ hybridization on hypothalamic sections from ovariectomized guinea pig using a cocktail of three 35S-labeled oligonucleotides complementary to mammalian progesterone receptor (PR) cDNA. PR mRNA was readily detected in hypothalamic neurons from guinea pigs pretreated with 17 beta-estradiol benzoate (E2B), but not from animals which did not receive supplemental E2B. The distribution of PR mRNA-containing cells corresponded well with previous localizations of PR in guinea pig. In contrast to earlier reports of E2B regulation of PR mRNA in rat hypothalamus, however, we found that PR mRNA remained elevated during chronic exposure to E2B (up to 10 days) in guinea pig. PMID:2072827

  5. Immunolocalization of a guinea pig sperm surface antigen recognized by a monoclonal antibody E74.

    PubMed Central

    Ilayperuma, Isurani

    2002-01-01

    E74 is a mouse monoclonal antibody raised against the acrosome-reacted guinea pig spermatozoa. This study describes immunolocalization of the E74 antigen in guinea pig spermatozoa. Immunoelectron microscopy of guinea pig spermatozoa shows that the E74 antigen is localized on the equatorial segment plasma membrane following the acrosome reaction but not associated with the surface of the acrosome-intact spermatozoa. Immunoblot analysis of Triton X-100 extract of cauda epididymal guinea pig spermatozoa following one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis shows that E74 antibody recognizes a protein with an apparent molecular weight of 45,000 dalton. Immunoblot of sperm extracts separated by two dimensional gel electrophoresis indicates a broad spot of 45,000 dalton in the 5 to 7.5 isoelectric focusing range. Images Figure 1 Figure 2 PMID:12074481

  6. Postnatal development of substance P in the inner ear of the guinea pig.

    PubMed

    Nowak, R; Zelck, U; Rathsack, R; Oehme, P; Scholtz, H J; Koitschev, A; Beleites, B

    1990-01-01

    Appreciable amounts of substance P (SP) were found in guinea pig cochleas. The highest values were found in the postnatal period. Data presented favor the assumption of SP acting as a neuromodulator or neurotransmitter in the inner ear. PMID:1693520

  7. Induction of follicular luteinization by equine chorionic gonadotropin in cyclic guinea pigs*

    PubMed Central

    Li, Jun-rong; Wang, Wei; Shi, Fang-xiong

    2015-01-01

    The effects of equine chorionic gonadotropin (eCG) on follicular development and ovulation in cyclic guinea pigs were investigated by histological and immunohistochemical analyses. Three groups of guinea pigs (n=12) were administrated subcutaneously with saline, 20 or 50 IU of eCG, respectively, on cyclic Day 12 (Day 1=vaginal openings). Ovaries were collected at 4 and 8 d after administration (6 animals per group each time). The eCG administration induced significant and distinct morphological changes in the ovaries, as it promoted the luteinization of granulosa cells, but not follicular development. In addition, proliferating cell nuclear antigen (PCNA) and steroidogenic acute regulatory protein (StAR) were immunolocalized specifically in luteinized follicles. Our experiments together indicate that eCG administration can induce follicular luteinization but not superovulation in guinea pigs. The eCG in cyclic guinea pigs functions similar to that of luteinizing hormone (LH), but not follicle-stimulating hormone (FSH). PMID:26642181

  8. Tissue distribution of the guinea-pig decay-accelerating factor.

    PubMed Central

    Nishikawa, K; Matsuo, S; Tamai, H; Okada, N; Okada, H

    1998-01-01

    MCA44 is a monoclonal antibody (mAb) to guinea-pig decay-accelerating factor (DAF) and, using this mAb, tissue distribution of guinea-pig DAF was studied by immunofluorescence. Guinea-pig DAF was found to be expressed not only on the vascular endothelium but also on different types of cells, such as the tubular epithelium of the kidney, epidermal cells of the skin and synovial lining cells. As there was no significant reduction in staining intensity with MCA44 following treatment with phosphatidylinositol-specific phospholipase C, many guinea-pig DAF molecules expressed in these tissues may be of the transmembrane form. Images Figure 1 Figure 2 Figure 3 PMID:9824490

  9. Guinea Pig Lung Lavage Cells After Intranasal BCG Sensitization

    PubMed Central

    Terai, T.; Ganguly, Rama; Waldman, Robert H.

    1979-01-01

    Recent studies have suggested that intranasal administration of antigen can induce local cell-mediated immunity in lung lavage cells. The present study was designed to examine the changes in composition of lung lavage cells and their capacity to produce the lymphokine migration inhibitory factor after intranasal immunization with BCG in guinea pigs. Results indicate that guinea pigs responded to respiratory tract BCG infection with an increase in immunocompetent cells in the bronchoalveolar tract and with production of migration inhibitory factor. After local pulmonary BCG administration, the total number of cells increased as compared with that of the uninfected animals, the increase being statistically significant within 2 weeks. This marked increase in the total cell population is due to a more than doubling of the number of macrophages in the lavage fluid. Animals also developed at this time positive delayed hypersensitivity to intradermally administered purified protein derivative. A significant increase in the total lymphoid cells and macrophage population was observed again at 6 weeks after sensitization, suggesting that the response is biphasic in nature. At 6 weeks, however, there was also a significant rise in total lymphocytes and T cell population in addition to macrophage numbers. This increase in T cells correlated with an increase in production of migration inhibitory factor in the presence of purified protein derivative. These data suggest that the immune response of the respiratory tract after BCG challenge involves increased recruitment of immunocompetent cells locally at the site of infection and that these cells are capable of producing effector molecules in terms of the elaboration of migration inhibitory factor. PMID:387595

  10. Acute and subchronic dermal toxicity of nanosilver in guinea pig

    PubMed Central

    Korani, M; Rezayat, SM; Gilani, K; Bidgoli, S Arbabi; Adeli, S

    2011-01-01

    Silver has been used as an antimicrobial agent for a long time in different forms, but silver nanoparticles (nanosilver) have recently been recognized as potent antimicrobial agents. Although nanosilver is finding diverse medical applications such as silver-based dressings and silver-coated medical devices, its dermal and systemic toxicity via dermal use has not yet been identified. In this study, we analyzed the potential toxicity of colloidal nanosilver in acute and subchronic guinea pigs. Before toxicity assessments, the size of colloidal nanosilver was recorded in sizes <100 nm by X-ray diffraction and transmission electron microscopy. For toxicological assessments, male guinea pigs weighing 350 to 400 g were exposed to two different concentrations of nanosilver (1000 and 10,000 μg/mL) in an acute study and three concentrations of nanosilver (100, 1000, and 10,000 μg/mL) in a subchronic study. Toxic responses were assessed by clinical and histopathologic parameters. In all experimental animals the sites of exposure were scored for any type of dermal toxicity and compared with negative control and positive control groups. In autopsy studies during the acute test, no significant changes in organ weight or major macroscopic changes were detected, but dose-dependent histopathologic abnormalities were seen in skin, liver, and spleen of all test groups. In addition, experimental animals subjected to subchronic tests showed greater tissue abnormalities than the subjects of acute tests. It seems that colloidal nanosilver has the potential to provide target organ toxicities in a dose- and time-dependent manner. PMID:21720498

  11. Blast cells transfer experimental hypersensitivity pneumonitis in guinea pigs

    SciTech Connect

    Schuyler, M.; Cook, C.; Listrom, M.; Fengolio-Preiser, C.

    1988-06-01

    We previously demonstrated that experimental hypersensitivity pneumonitis (HP) can be transferred by lymph node cells (LNC) cultured in vitro with antigen. The purpose of this study was to identify the cells responsible for transfer and to determine if pulmonary cells can transfer HP. We cultured LNC from sensitized Strain 2 guinea pigs with a soluble extract of Micropolyspora faeni for 72 h, separated lymphoblasts from small lymphocytes, and transferred both subpopulations intravenously to syngeneic recipients. We also transferred irradiated lymphoblasts (1,500 rads), macrophage-depleted, lymphoblast-enriched populations, and pulmonary cells either without culture or after culture with M. faeni. Control animals received an equal volume of medium. All recipient animals were challenged intratracheally (i.t.) with M. faeni 48 h after the cell transfer, and they were killed 4 days after i.t. challenge. Randomly selected microscopic fields of the lung (250/animal) were judged to be normal or abnormal without knowledge of treatment. This measurement was reproducible (r = 0.95 for duplicate measurements, n = 55). All guinea pigs were maintained in HEPA-filtered air. There was a low level of pulmonary response to an i.t. challenge of M. faeni in animals that received medium. Animals that received pulmonary cells, either cultured or noncultured, did not differ from those in the control group. There was a substantial increase (p less than 0.01) in the extent of pulmonary abnormalities in the recipients of the lymphoblast population, with significant correlation (r = 0.87, p less than 0.01) between the number of lymphoblasts transferred and the extent of pulmonary abnormalities.

  12. Pharmacokinetics of activated protein C in guinea pigs

    SciTech Connect

    Berger, H. Jr.; Kirstein, C.G.; Orthner, C.L. )

    1991-05-15

    Protein C is a vitamin K-dependent zymogen of the serine protease, activated protein C (APC), an important regulatory enzyme in hemostasis. In view of the potential of human APC as an anticoagulant and profibrinolytic agent, the pharmacokinetics and tissue distribution of APC were studied in guinea pigs. The plasma elimination of a trace dose of {sup 125}I-APC was biphasic following an initial rapid elimination of approximately 15% of the injected dose within 1 to 2 minutes. This rapid removal of {sup 125}I-APC from the circulation was found to be a result of an association with the liver regardless of the route of injection. Essentially identical results were obtained with active site-blocked forms of APC generated with either diisopropylfluorophosphate or D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone, which indicates that the active site was not essential for the liver association. Accumulation of all three forms of APC in the liver peaked at 30 minutes and then declined as increasing amounts of degraded radiolabeled material appeared in the gastrointestinal tract and urine. Removal of the gamma-carboxyglutamic acid (gla) domain of diisopropylphosphoryl-APC resulted in a 50% reduction in the association with liver and an accumulation in the kidneys. Protein C and protein S were cleared from the circulation at rates approximately one-half and one-fourth, respectively, that of APC. Both in vitro and in vivo, APC was found to form complexes with protease inhibitors present in guinea pig plasma. Complex formation resulted in a more rapid disappearance of the enzymatic activity of APC than elimination of the protein moiety. These findings indicate two distinct mechanisms for the elimination of APC. One mechanism involves reaction with plasma protease inhibitors and subsequent elimination by specific hepatic receptors. (Abstract Truncated)

  13. A Pilot Study of Uterine Artery Embolization with Tris-Acryl Gelatin Microspheres in Guinea Pigs

    SciTech Connect

    Zhuang Wenquan; Tan Guosheng; Guo Wenbo; Yang Jianyong

    2012-06-15

    Objective: This study was designed to establish guinea pigs as an animal model for uterine artery embolization (UAE) with tris-acryl gelatin microspheres (TAGM). Methods: Twenty-five female adult guinea pigs were randomly divided into two groups, including a uterine artery casting mould group (n = 10) and a UAE group (n = 15). Pelvic angiography and vascular casting mould were performed in the first group. The anatomical characters of the pelvic cavity in guinea pigs were described. In the second group, the technical feasibility of performing UAE with TAGM in guinea pigs was investigated. The histopathological slides of the uterus of guinea pigs after UAE were examined to inspect the outcomes of UAE. Results: The uterine artery springs from the internal iliac artery, ascends tortuously along the cervix, and gives off vertically 8-10 branches to the cervix uteri and uterine horns. The diameters of the trunk of the uterine artery and its first branch were 0.32 {+-} 0.027 mm and 0.14 {+-} 0.01 mm, respectively. For UAE animals, the dosages of 40-120 and 100-300 {mu}m TAGM were 0.033 {+-} 0.003 ml and 0.015 {+-} 0.002 ml, respectively. On histopathological slides, embosphere particles were found in the first branches of the uterine artery, the subserous arteries, and the intramural arteries. Inflammatory reactions in the uterus were common in guinea pigs after UAE. Local or dispersed areas of necrosis in uterus also were observed in a few guinea pigs. Conclusions: Guinea pigs are an appropriate and feasible model for UAE with TAGM.

  14. Bitter avoidance in Guinea Pigs (Cavia porcellus) and Mice (Mus musculus and Peromyscus leucopus)

    PubMed Central

    Field, Kristin L.; Beauchamp, Gary K.; Kimball, Bruce A.; Mennella, Julie A.; Bachmanov, Alexander A.

    2010-01-01

    Rejection of bitter substances is common in many species and may function to protect an animal from ingestion of bitter-tasting toxins. Since many plants are bitter, it has been proposed that high tolerance for bitterness would be adaptive for herbivores. Earlier studies conducted on herbivorous guinea pigs (Cavia porcellus) have been used to support this proposal. We tested guinea pigs with bitter plant secondary metabolites (salicin, caffeine, quinine hydrochloride) and bitter protein hydrolysates (two types of hydrolyzed casein, hydrolyzed soy) in a series of two-choice preference tests. For comparison, we tested two non-herbivorous mouse species (Mus musculus and Peromyscus leucopus). Guinea pigs did show weaker avoidance of QHCl than did the mice, confirming predictions generated from earlier work. However, guinea pigs had similar responses to caffeine as did Peromyscus. Both of these species showed weaker avoidance responses than Mus to 10 mM caffeine. For salicin, guinea pigs were the only species to avoid it at 10 mM and their preference scores at this concentration were significantly lower than for the two mice species. Guinea pigs avoided all of the protein hydrolysates more strongly than the other species. Responses to the protein hydrolysates did not reflect the patterns observed with the simple bitter compounds, suggesting that other properties of these complex stimuli may be responsible for guinea pig avoidance of them. Our results suggest caution in accepting, without further empirical support, the premise that guinea pigs (and herbivores in general) have a generalized reduced bitter sensitivity. PMID:21090891

  15. Protective activity of calcium entry blockers against ouabain intoxication in anesthetized guinea pigs.

    PubMed

    Jonkman, F A; Boddeke, H W; van Zwieten, P A

    1986-01-01

    Several studies have suggested a central role for calcium in the pathogenesis of digitalis-induced arrhythmias. To test this hypothesis, the effects on ouabain-induced arrhythmia of intraarterial pretreatment with the calcium entry blockers nifedipine, flunarizine, verapamil, diltiazem, and bepridil, the calcium entry promotor Bay K 8644, and CaCl2 were compared with those of the currently applied digitalis antidotes phenytoin and lidocaine in urethane-anesthetized (1.5 g/kg i.p.) guinea pigs. Pretreatment with nifedipine (0.03 and 0.1 mg/kg), flunarizine (1 and 3 mg/kg), and phenytoin (10 mg/kg) doubled the time (from 10-20 to 20-40 min) required to provoke toxic ECG changes. Verapamil, diltiazem, and bepridil caused a slight but significant reduction of ouabain toxicity. Pretreatment with CaCl2 (10 mg/kg) enhanced all toxic effects of ouabain. None of the above-mentioned pretreatments as such changed the ECG parameters. Bay k 8644 (0.03 and 0.1 mg/kg) enhanced the effects of ouabain on ventricular rhythm, but abolished the ouabain-induced impairment of AV conduction. Bay k 8644 as such increased heart rate (from 318 +/- 11 to 376 +/- 6 beats/min at 0.1 mg/kg) and shortened the PR interval. The negative inotropic effects of the calcium entry blockers were quantified in electrically paced (3 Hz) guinea pig isolated left atria 15 min after pretreatment with ouabain (3 X 10(-7) M). The rank order of potency for the negative inotropic effect was nifedipine greater than verapamil greater than bepridil greater than diltiazem greater than flunarizine. In conclusion, nifedipine, flunarizine, and phenytoin showed obvious and equally effective protection against ouabain-induced arrhythmia.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2429073

  16. Chlamydia caviae infection alters abundance but not composition of the guinea pig vaginal microbiota

    PubMed Central

    Neuendorf, Elizabeth; Gajer, Pawel; Bowlin, Anne K.; Marques, Patricia X.; Ma, Bing; Yang, Hongqiu; Fu, Li; Humphrys, Michael S.; Forney, Larry J.; Myers, Garry S.A.; Bavoil, Patrik M.; Rank, Roger G.; Ravel, Jacques

    2015-01-01

    In humans, the vaginal microbiota is thought to be the first line of defense again pathogens including Chlamydia trachomatis. The guinea pig has been extensively used as a model to study chlamydial infection because it shares anatomical and physiological similarities with humans, such as a squamous vaginal epithelium as well as some of the long-term outcomes caused by chlamydial infection. In this study, we aimed to evaluate the guinea pig-C. caviae model of genital infection as a surrogate for studying the role of the vaginal microbiota in the early steps of C. trachomatis infection in humans. We used culture-independent molecular methods to characterize the relative and absolute abundance of bacterial phylotypes in the guinea pig vaginal microbiota in animals non-infected, mock-infected or infected by C. caviae. We showed that the guinea pig and human vaginal microbiotas are of different bacterial composition and abundance. Chlamydia caviae infection had a profound effect on the absolute abundance of bacterial phylotypes but not on the composition of the guinea pig vaginal microbiota. Our findings compromise the validity of the guinea pig-C. caviae model to study the role of the vaginal microbiota during the early steps of sexually transmitted infection. PMID:25761873

  17. Immunogenicity of guinea pig cells transformed in culture by chemical carcinogens

    SciTech Connect

    Ohanian, S.H.; McCabe, R.P.; Evans, C.H.

    1981-12-01

    The immunogenicity of inbred strain 2/N guinea pig fibroblasts transformed to the malignant state in vitro by chemical carcinogens was evaluated with the use of a variety of in vivo and in vitro methods including delayed-type hypersensitivity skin and tumor transplantation tests and analysis of antibody production by immunofluorescence, complement fixation, and staphylococcal protein A binding tests. Neoplastic transformation was induced by direct treatment of cells in culture with benzo(a)pyrene, 3-methylcholanthrene, or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or by the host-mediated method by which fetuses were exposed to diethylnitrosamine or MNNG in vivo prior to cell culture. Rabbits and syngeneic guinea pigs were inoculated with unirradiated and X-irradiated clonally derived cells. Delayed hypersensitivity skin reactions to immunizing or other cells were equivalent in immunized or control guinea pigs, and no protection to tumor outgrowth from a challenge inoculum of immunizing cells was observed. Antibody activity induced in the sera of immunized guinea pigs was cross-reactive and removed by absorption with nontumorigenic cells. Rabbit antisera after absorption with fetal guinea pig cells were nonreactive with the specific immunizing or other culture cells. Chemical carcinogen-induced neoplastic transformation of guinea pig cells can, therefore, occur without formation of detectable, individually distinct cell surface tumor-specific neoantigens.

  18. Immunogenicity of guinea pig cells transformed in culture by chemical carcinogens

    SciTech Connect

    Ohanian, S.H.; McCabe, R.P.; Evans, C.H.

    1981-12-01

    The immunogenicity of inbred strain 2/N guinea pig fibroblasts transformed to the malignant state in vitro by chemical carcinogens was evaluated with the use of a variety of in vivo and in vitro methods including delayed-type hypersensitivity skin and tumor transplantation tests and analysis of antibody production by immunofluorescence, complement fixation, and staphylococcal protein A binding tests. Neoplastic transformation was induced by direct treatment of cells in culture with benzo(a)pyrene, 3-methylcholanthrene, or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or by the host-mediated method by which fetuses were exposed to diethylnitrosamine or MNNG in vivo prior to cell culture. Rabbits and syngeneic guinea pigs were inoculated with unirradiated and X-irradiated clonally derived cells. Delayed hypersensitivity skin reactions to immunizing or other cells were equivalent in immunized or control guinea pigs, and no protection to tumor outgrowth from a challenge inoculum of immunizing cells was observed. Antibody activity induced in the sera of immunized guinea pigs was cross-reactive and removed by absorption with nontumorigenic cells. Rabbit anitsera after absorption with fetal guinea pig cells were nonreactive with the specific immunizing or other cultured cells. Chemical carcinogen-induced neoplastic transformation of guinea pig cells can, therefore, occur without formation of detectable, individually distinct cell surface tumor-specific neoantigens.

  19. Studies on dioctyl sodium sulfosuccinate toxicity: clinical, gross and microscopic pathology in the horse and guinea pig.

    PubMed

    Moffatt, R E; Kramer, L L; Lerner, D; Jones, R

    1975-10-01

    Concentrations of dioctyl sodium sulfosuccinate (DSS) ranging from three to five times the recommended dosage produced severe diarrhea, rapid dehydration and death in seven horses and 66 guinea pigs when administered experimentally per os. Clinicopathological findings indicated hemoconcentration in both horses and guinea pigs. There was a leucocytosis in the guinea pigs given the highest dosages. In all cases the principal finding at necropsy was extreme fluid distention of the intestinal tract. There was histopathological evidence of epithelial denudation and vascular stasis. The LD50 in the guinea pig was approximately 0.65 g DSS/kg body weight. PMID:1175077

  20. Genistein stimulates myocardial contractility in guinea pigs by different subcellular mechanisms.

    PubMed

    Li, Hongfang; Zhang, Yingfu; Tian, Zhifeng; Qiu, Xiaoqing; Gu, Jing; Wu, Jinxia

    2008-11-12

    The purpose of this study was to investigate the mechanisms involved in the excitatory effect induced by genistein in isolated guinea pig left ventricular papillary muscles and to determine relationship of genistein action with the tyrosine kinase pathway and phosphatidylinositol 3-kinase (PI3K) activity, the cyclic adenosine 5'-monophosphate (cAMP) signal system and the sarcoplasmic reticulum Ca2+ mobilization. Genistein (1-100 microM) significantly increased contraction of left ventricular papillary muscles from male and female guinea pigs in a concentration-dependent manner and its action had no obvious gender differences. Prior treatment with an L-type Ca2+ channel blocker verapamil hydrochloride, beta-adrenoceptor inhibitors propranolol and atenolol, an inhibitor of Na+-Ca2+ reverse exchanger Kb-r7943 or the blocker of estrogen receptor ICI 182,780 failed to alter the positive inotropic effect induced by genistein in papillary muscles. However, tyrosine phosphatase inhibitor, sodium orthovanadate or a potent phosphotyrosine phosphatase inhibitor bpV (phen) could partly but significantly reduce the stimulatory action of genistein. Interestingly, insulin-like growth factor-1, a known PI3K activator could also decrease the stimulatory action of genistein obviously, but the PI3K inhibitor LY294002 had no significant effect on the stimulatory action of genistein. The excitatory effect of genistein was markedly attenuated not only after treatment with an inhibitor of cAMP synthesis Sq 22536, carbachol or an inhibitor of specific protein kinase A H-89, but also after the inhibition of sarcoplasmic reticulum Ca2+ mobilization by ruthenium red, ryanodine or the inhibitor of sarcoplasmic reticulum Ca2+-ATPase thapsigargin. All these results indicate that the excitatory effects of genistein in papillary muscles are due to the inhibition of tyrosine kinase pathway and PI3K activity, thereby locally activating cAMP signal transduction and facilitating intracellular Ca2

  1. Sex differences in the mechano-energetic effects of genistein on stunned rat and guinea pig hearts.

    PubMed

    Colareda, Germán A; Ragone, María I; Consolini, Alicia E

    2016-01-01

    Although the phytoestrogen genistein (Gen) is considered protective in cardiovascular diseases, its direct effects on stunned hearts after transient ischemia-reperfusion (I/R) are unknown. This report studied the effects of 20 μmol/L Gen on the mechano-calorimetric behaviour during I/R of rat and guinea pig hearts to evaluate the energetics of Ca(2+) homeostasis. Isolated beating hearts were perfused with control Krebs solution inside a calorimeter with or without perfusion of Gen before a transient period of I/R. Left ventricular pressure development (P) and total heat rate (Ht) were continuously measured. At 37°C, Gen did not change post-ischemic contractile recovery (PICR), but it increased the relaxation rate. However, PICR was reduced in hearts of male rats and guinea pigs at 30°C. Total muscle economy (P/Ht) showed the same behaviour as P at each temperature. Inhibition of phosphatases with orthovanadate during Gen perfusion prevented a decrease in PICR in male rat hearts, suggesting that this effect is due to tyrosine kinase inhibition. Reperfusing ischemic hearts with 10 mmol/L caffeine-36 mmol/L Na(+)-Krebs induced contracture dependent on the sarcoreticular Ca(2+) content. Contracture relaxation depends on mitochondrial Ca(2+) uptake and Gen reduced the relaxation rate. Moreover, Gen prevented the increase in Rhod-2 fluorescence (free [Ca(2+)]m) of rat cardiomyocytes. In guinea pig hearts, Gen maintained ischemic preconditioning, but was reduced by 5-hydroxydecanoate, suggesting the participation of mitochondrial adenosine triphosphate (ATP)-dependent K channels. Results suggest that Gen acts on several mechanisms that regulate myocardial calcium homeostasis and energetics during I/R, which differ in a temperature- and sex-dependent manner. PMID:26452245

  2. The role of the anaesthetised guinea-pig in the preclinical cardiac safety evaluation of drug candidate compounds

    SciTech Connect

    Marks, Louise; Borland, Samantha; Philp, Karen; Ewart, Lorna; Lainée, Pierre; Skinner, Matthew; Kirk, Sarah; Valentin, Jean-Pierre

    2012-09-01

    Despite rigorous preclinical and clinical safety evaluation, adverse cardiac effects remain a leading cause of drug attrition and post-approval drug withdrawal. A number of cardiovascular screens exist within preclinical development. These screens do not, however, provide a thorough cardiac liability profile and, in many cases, are not preventing the progression of high risk compounds. We evaluated the suitability of the anaesthetised guinea-pig for the assessment of drug-induced changes in cardiovascular parameters. Sodium pentobarbitone anaesthetised male guinea-pigs received three 15 minute intravenous infusions of ascending doses of amoxicillin, atenolol, clonidine, dobutamine, dofetilide, flecainide, isoprenaline, levosimendan, milrinone, moxifloxacin, nifedipine, paracetamol, verapamil or vehicle, followed by a 30 minute washout. Dose levels were targeted to cover clinical exposure and above, with plasma samples obtained to evaluate effect/exposure relationships. Arterial blood pressure, heart rate, contractility function (left ventricular dP/dt{sub max} and QA interval) and lead II electrocardiogram were recorded throughout. In general, the expected reference compound induced effects on haemodynamic, contractility and electrocardiographic parameters were detected confirming that all three endpoints can be measured accurately and simultaneously in one small animal. Plasma exposures obtained were within, or close to the expected clinical range of therapeutic plasma levels. Concentration–effect curves were produced which allowed a more complete understanding of the margins for effects at different plasma exposures. This single in vivo screen provides a significant amount of information pertaining to the cardiovascular risk of drug candidates, ultimately strengthening strategies addressing cardiovascular-mediated compound attrition and drug withdrawal. -- Highlights: ► Evaluation of the anaesthetised guinea-pig to determine cardiac liability.

  3. Experimental microembolism induces localized neuritic pathology in guinea pig cerebrum.

    PubMed

    Li, Jian-Ming; Cai, Yan; Liu, Fei; Yang, La; Hu, Xia; Patrylo, Peter R; Cai, Huaibin; Luo, Xue-Gang; Xiao, Dong; Yan, Xiao-Xin

    2015-05-10

    Microbleeds are a common finding in aged human brains. In Alzheimer's disease (AD), neuritic plaques composed of β-amyloid (Aβ) deposits and dystrophic neurites occur frequently around cerebral vasculature, raising a compelling question as to whether, and if so, how, microvascular abnormality and amyloid/neuritic pathology might be causally related. Here we used a guinea pig model of cerebral microembolism to explore a potential inductive effect of vascular injury on neuritic and amyloid pathogenesis. Brains were examined 7-30 days after experimental microvascular embolization occupying ~0.5% of total cortical area. Compared to sham-operated controls, glial fibrillary acidic protein immunoreactivity was increased in the embolized cerebrum, evidently around intracortical vasculature. Swollen/sprouting neurites exhibiting increased reactivity of nicotinamide adenine dinucleotide phosphate diaphorase, parvalbumin, vesicular glutamate transporter 1 and choline acetyltransferase appeared locally in the embolized brains in proximity to intracortical vasculature. The embolization-induced swollen/sprouting neurites were also robustly immunoreactive for β-amyloid precursor protein and β-secretase-1, the substrate and initiating enzyme for Aβ genesis. These experimental data suggest that microvascular injury can induce multisystem neuritic pathology associated with an enhanced amyloidogenic potential in wild-type mammalian brain. PMID:25871402

  4. Interaction between titanium and cadmium in various guinea pig organs.

    PubMed

    Takano, Takashi; Kaneda, Takeharu; Kaneshige, Masaki; Tsutsumi, Tomoko; Ochiai, Yoshitsugu; Shimizu, Kazumasa; Hondo, Ryo; Mochizuki, Mariko; Ueda, Fukiko

    2013-02-01

    Titanium (Ti) is used in many fields, while cadmium (Cd) is known to cause the itai-itai disease. In the present study, possible interactions between titanium and cadmium were investigated. Aorta, taenia coli, and liver were removed from male guinea pigs. Muscle tension was measured using intact aorta and taenia coli and using β-escin-permeabilized taenia coli in a physiological salt solution and a hyperpotassium solution containing Cd and/or Ti. Cellular Cd contents were determined using all tissues after washout with EDTA solution. Cadmium-induced relaxation in the hyperpotassium solution recovered significantly (P < 0.01) following Ti treatment in taenia coli, but not in the aorta. In β-escin-permeabilized taenia coli, the percentage recoveries after Cd treatment and after Ti plus Cd treatment were 67.3 ± 8.7 % (n = 4) and 87.7 ± 3.8 % (n = 4), respectively, compared with Ca-induced control contraction. Cellular Cd contents in taenia coli decreased significantly following treatment with Ti 10(-4) M. Although similar results were obtained using the aorta and the liver, there were no significant differences between the control and Ti 10(-5) M. High concentrations of Ti may reduce cellular Cd content. PMID:23238609

  5. Biosynthesis of glucagon in isolated pancreatic islets of guinea pigs

    PubMed Central

    Hellerström, Claes; Howell, Simon L.; Edwards, John C.; Andersson, Arne; Östenson, Claes-Göran

    1974-01-01

    1. The biosynthesis of glucagon in guinea-pig A2 cells was investigated by incubation of isolated islets of Langerhans in the presence of [3H]tryptophan for periods of up to 14 days. Proteins were extracted from islets and incubation media and analysed by gel filtration. 2. In addition to very-high-molecular-weight (100000) proteins, the principal tryptophan-containing biosynthetic product after incubation for up to 17h was a protein of minimum mol.wt. 9000, which co-eluted on gel filtration with a peak of glucagon-like immunoreactivity, but was apparently devoid of biological activity in a fat-cell assay. A discrete peak of labelled glucagon was only recovered after incubation for at least 6 days. Losses of glucagon during the extraction and rapid secretion of newly synthesized glucagon into incubation media were excluded as reasons for the lack of recovery of labelled hormone from islets after shorter incubations. 3. The 9000-mol.wt. protein was localized to A2 cells in experiments using B-cell-depleted islets, and to A2-cell granules by subcellular fractionation and electron-microscopic radioautography. Only glucagon was secreted into the incubation medium. 4. Possible relationships between the 9000-mol.wt. protein and glucagon are discussed in the light of postulated mechanisms of glucagon biosynthesis. PMID:4615708

  6. In vivo imaging and vibration measurement of Guinea pig cochlea

    NASA Astrophysics Data System (ADS)

    Choudhury, Niloy; Chen, Fangyi; Zheng, Jiefu; Nuttall, Alfred L.; Jacques, Steven L.

    2008-02-01

    An optical coherence tomography (OCT) system was built to acquire in vivo, both images and vibration measurements of the organ of Corti of the guinea pig. The organ of Corti was viewed through a ~500-μm diameter hole in the bony wall of the scala tympani of the first cochlear turn. In imaging mode, the image was acquired as reflectance R(x,z). In vibration mode, the basilar membrane (BM) or reticular lamina (RL) was selected based on the image. Under software control, the system would move the scanning mirrors to bring the sensing volume of the measurement to the desired tissue location. To address the gain stability problem of the homodyne OCT system, arising from the system moving in and out of the quadrature point and also to resolve the 180 degree ambiguity in the phase measurement using an interferometer, a vibration calibration method is developed by adding a vibrating source to the reference arm to monitor the operating point of the interferometric system. Amplitude gain and phase of various cochlear membranes was measured for different sound pressure level (SPL) varying from 65dB SPL to 93 dB SPL.

  7. Gene Targeting to the Uteroplacental Circulation of Pregnant Guinea Pigs.

    PubMed

    Mehta, Vedanta; Ofir, Keren; Swanson, Anna; Kloczko, Ewa; Boyd, Michael; Barker, Hannah; Avdic-Belltheus, Adnan; Martin, John; Zachary, Ian; Peebles, Donald; David, Anna L

    2016-08-01

    Our study aimed to target adenoviral gene therapy to the uteroplacental circulation of pregnant guinea pigs in order to develop a novel therapy for fetal growth restriction. Four methods of delivery of an adenovirus encoding β-galactosidase (Ad.LacZ) were evaluated: intravascular injection using phosphate-buffered saline (PBS) into (1) uterine artery (UtA) or (2) internal iliac artery or external administration in (3) PBS or (4) pluronic F-127 gel (Sigma Aldrich). Postmortem examination was performed 4 to 7 days after gene transfer. Tissue transduction was assessed by X-gal histochemistry and enzyme-linked immunosorbent assay. External vascular application of the adenovirus vector in combination with pluronic gel had 91.7% success rate in terms of administration (85% maternal survival) and gave the best results for maternal/fetal survival and local transduction efficiency without any spread to maternal or fetal tissues. This study suggests an optimal method of gene delivery to the UtAs of a small rodent for preclinical studies. PMID:26865541

  8. Antitussive activity of iodo-resiniferatoxin in guinea pigs

    PubMed Central

    Trevisani, M; Milan, A; Gatti, R; Zanasi, A; Harrison, S; Fontana, G; Morice, A; Geppetti, P

    2004-01-01

    Background: Iodo-resiniferatoxin (I-RTX) has recently been described as an ultra potent antagonist of the transient receptor potential vanilloid-1 (TRPV1). Methods: The ability of I-RTX to inhibit cough induced by inhalation of two putative TRPV1 stimulants (capsaicin and citric acid) was tested in non-anaesthetised guinea pigs. Results: Pretreatment with I-RTX either intraperitoneally (0.03–0.3 µmol/kg) or by aerosol (0.1–3 µM) reduced the number of coughs produced by inhalation of citric acid (0.25 M) and capsaicin (30 µM) in a dose dependent manner. Capsazepine (CPZ) also reduced citric acid and capsaicin induced cough, but the activity of I-RTX was 10–100 times more potent than CPZ in all the experimental conditions tested. Conclusions: I-RTX is a novel and potent antitussive drug which inhibits cough mediated by agents possibly acting via TRPV1 activation. PMID:15333853

  9. Experimental microembolism induces localized neuritic pathology in guinea pig cerebrum

    PubMed Central

    Li, Jian-Ming; Cai, Yan; Liu, Fei; Yang, La; Hu, Xia; Patrylo, Peter R.; Cai, Huaibin; Luo, Xue-Gang; Xiao, Dong; Yan, Xiao-Xin

    2015-01-01

    Microbleeds are a common finding in aged human brains. In Alzheimer's disease (AD), neuritic plaques composed of β-amyloid (Aβ) deposits and dystrophic neurites occur frequently around cerebral vasculature, raising a compelling question as to whether, and if so, how, microvascular abnormality and amyloid/neuritic pathology might be causally related. Here we used a guinea pig model of cerebral microembolism to explore a potential inductive effect of vascular injury on neuritic and amyloid pathogenesis. Brains were examined 7-30 days after experimental microvascular embolization occupying ~0.5% of total cortical area. Compared to sham-operated controls, glial fibrillary acidic protein immunoreactivity was increased in the embolized cerebrum, evidently around intracortical vasculature. Swollen/sprouting neurites exhibiting increased reactivity of nicotinamide adenine dinucleotide phosphate diaphorase, parvalbumin, vesicular glutamate transporter 1 and choline acetyltransferase appeared locally in the embolized brains in proximity to intracortical vasculature. The embolization-induced swollen/sprouting neurites were also robustly immunoreactive for β-amyloid precursor protein and β-secretase-1, the substrate and initiating enzyme for Aβ genesis. These experimental data suggest that microvascular injury can induce multisystem neuritic pathology associated with an enhanced amyloidogenic potential in wild-type mammalian brain. PMID:25871402

  10. Observations on chloralose-induced myoclonus in guinea-pigs.

    PubMed Central

    Chadwick, D.; Hallett, M.; Jenner, P.; Marsden, C. D.

    1980-01-01

    1 The physiological, biochemical and pharmacological features of alpha-chloralose-induced myoclonus in the guinea-pig have been studied. 2 EMG bursts in muscles jerking in chloralose-induced myoclonus are long, and are not time-locked to any cortical event recorded in the EEG, although they are evoked by auditory or peripheral nerve stimuli. 3 The efferent conduction velocity down the spinal cord of the signals generating the EMG bursts is fast but the afferent conduction velocity up the cord for stimulus-evoked jerks is slow, in distinction to the reverse characteristics of the spino-bulbo-spinal relfex arc. 4 alpha-Choralose did not cause any consistent change in 5-hydroxytryptamine (5-HT) or 5-hydroxyindoleacetic acid levels in any brain area, nor did it alter 5-HT turnover as judged by the depletion of 5-HT after p-chlorophenylalanine pretreatment. 5 Pretreatment of animals with drugs that increase brain 5-HT action (L-tryptophan with a monoamine oxidase inhibitor, or 5-hydroxytryptophan), or antagonize the action of 5-HT (cyproheptadine) did not abolish or obviously increase chloralose-induced myoclonus. 6 Chloralose-induced myoclonus is not similar to 5-HT-sensitive reticular reflex myoclonus in man. PMID:6156735

  11. Particle size influences aerosol deposition in guinea pigs during bronchoconstriction

    SciTech Connect

    Praud, J.P.; Macquin-Mavier, I.; Wirquin, V.; Meignan, M.; Harf, A.

    1986-03-01

    The role of two factors determining the deposition of aerosols in the respiratory tract was investigated: the particle size and the nature of the airflow in the airways. An aerosol of Tc99 m-DTPA was generated, with a mass median aerodynamic diameter of either 3 ..mu..m (Bird nebulizer) or 0.5 ..mu..m (Jouan nebulizer). The vehicle was either saline (S) or histamine (H) at a concentration which was previously shown to induce a 50% decrease of specific airway conductance. Spontaneously breathing guinea pigs were exposed during 2 minutes to the aerosol, then killed and the radioactivity in the pharynx, the trachea, the large bronchi and the remaining parenchyma was measured. Results are evaluated as the percentage of total radioactivity in the respiratory tract (mean +/- SEM). Analysis of variance showed that there was a significant difference in the pattern of deposition for large particles (3 ..mu..m) during bronchoconstriction: the more proximal deposition can be ascribed to inertial impaction. Particle size should be clearly defined during histamine challenge in experimental animals.

  12. Epidermal cell proliferation in guinea pigs with experimental dermatophytosis

    SciTech Connect

    Tagami, H.

    1985-08-01

    To elucidate the mechanisms underlying the self-healing process of experimental dermatophytosis produced in guinea pigs by an occlusive method with Trichophyton mentagrophytes, epidermal proliferative activity was evaluated by the in vivo tritiated thymidine-labeling technique performed at various intervals after the first and second infections. Determination of labeling indices disclosed that an increased epidermal proliferation correlated well with the severity of inflammatory changes, i.e., a peak activity was noted after 10 days in primary infection and at 2 days in reinfection, respectively, and was followed by subsequent spontaneous lesion clearance after 10 days. Application of a heat-killed spore suspension produced inflammatory changes with enhanced epidermopoiesis, similar to those induced by reinoculation of living spores, only in immune animals. The present results indicate that the dermatitic changes occurring in experimental dermatophytosis increase epidermopoiesis which facilitates elimination of the fungus from the stratum corneum and that host immune activity, particularly contact sensitivity to fungal antigen, exerts a crucial role to induce these changes.

  13. Respiratory response of guinea pigs to zinc oxide fume

    SciTech Connect

    Amdur, M.O.; McCarthy, J.F.; Gill, M.W.

    1983-02-01

    Zinc has been found enriched in the fine particle fraction of atmospheric aerosols and in the surface layer of fly ash. Experimental combustion studies of coal have demonstrated that zinc is vaporized and recondensed into the submicrometer fraction of the combustion aerosols. This size fraction may contain as much as 1.5% zinc when a coal of high zinc content (Illinois No. 6) is used. Zinc sulfate and zinc ammonium sulfate are among the sulfates with demonstrable irritant potency. Zinc oxide was thus chosen as the initial aerosol for studies of biological and chemical interaction of high temperature generated submicrometer metal oxides with sulfur dioxide. This paper reports the respiratory response of guinea pigs to short term exposure to freshly formed zinc oxide fume. These studies of zinc oxide alone have relevance to industrial exposure. The recommended TLV for zinc oxide is 5 mg/m/sup 3/ and the recommended STEL is 10 mg/m/sup 3/. Concentrations used in our studies were below these recommended levels.

  14. Absorption Kinetics of Subcutaneously Administered Ceftazidime in Hypoperfused Guinea Pigs

    PubMed Central

    Ebihara, Tsuyoshi; Oshima, Shinji; Okita, Mitsuyoshi; Shiina, Sayumi; Negishi, Akio; Ohara, Kousuke; Ohshima, Shigeru; Iwasaki, Hiroyuki; Yoneyama, Akira; Kitazumi, Eiji; Kobayashi, Daisuke

    2014-01-01

    Background Pneumonia is the most common cause of death in patients with severe motor and intellectual disabilities (SMID), and intravenous ceftazidime (CAZ) is a widely used treatment for such infections. However, intravenous administration in patients with SMID may be difficult because of insufficient vascular development. Objectives The aim of our study was to determine the feasibility of subcutaneous drug administration by mentholated warm compresses (WMCs) as an alternative delivery method for ceftazidime in patients with SMID. Methods CAZ was subcutaneously administered to the abdominal region of naphazoline-treated hypoperfused guinea pigs, which were used as a hemodynamic model of patients with SMID. MWCs or warm compresses (WCs) were applied to the injection site to increase blood flow. We calculated the cumulative CAZ absorption over time by using the deconvolution method. Results Application of MWCs or WCs increased blood flow at the administration site and increased CAZ plasma levels. Application of MWCs or WCs after subcutaneous CAZ injection led to higher CAZ plasma levels than the mutant prevention concentration for a longer period than was observed for CAZ administration without the application of MWCs or WCs. Conclusions The application of MWCs or WCs enhanced subcutaneous CAZ absorption by increasing blood flow. MWCs and WCs are considered to be safe and routine methods to induce defecation after surgery on the digestive system; thus, the combination of these methods and subcutaneous CAZ administration is a potential method for treating pneumonia in patients with SMID. PMID:26649076

  15. Ouabain uptake by endocytosis in isolated guinea pig atria

    SciTech Connect

    Nunez-Duran, H.; Riboni, L.; Ubaldo, E.; Kabela, E.; Barcenas-Ruiz, L. Instituto Nacional de Cardiologia, Mexico DF )

    1988-10-01

    Mammalian cells specifically internalize some molecular species through receptor-mediated endocytosis (RME). The authors have used four different experimental protocols to investigate whether ouabain enters cardiac cells of guinea pig atrium through this pathway. First, by electron microscope morphometry the authors found that ouabain increased endocytic vesicles in atrial cells. Second, by scintillation counting they found that ({sup 3}H)ouabain uptake by the tissue is decreased by three treatments that decrease RME, i.e., NH{sub 4}Cl, trifluoperazine, and 16 mM (K{sup +}){sub 0}. Third, by radioautography at the electron microscope level, they checked that in preceding experiments ({sup 3}H)ouabain was washed out of plasma membrane after 60-min rinse and interiorized into the cardiac cells. Fourth, isometric tension recordings showed that the positive inotropic effect of ouabain was diminished in the presence of inhibitors, whereas that of a hydrophobic analogue, ouabagenin, was not affected. These results suggest that ouabain enters cardiac cells through RME and also that an intracellular site may, at least in part, be responsible for its inotropic effect.

  16. Demonstration of a specific C3a receptor on guinea pig platelets

    SciTech Connect

    Fukuoka, Y.; Hugli, T.E.

    1988-05-15

    Guinea pig platelets reportedly contain receptors specific for the anaphylatoxin C3a based on both ligand-binding studies and functional responses. A portion of the human 125I-C3a that binds to guinea pig platelets is competitively displaced by excess unlabeled C3a; however, the majority of ligand uptake was nonspecific. Uptake of 125I-C3a by guinea pig platelets is maximal in 1 min, and stimulation of guinea pig platelets by thrombin, ADP, or the Ca2+ ionophore A23187 showed little influence on binding of the ligand. Scatchard analysis indicated that approximately 1200 binding sites for C3a exist per cell with an estimated Kd of 8 x 10(-10) M. Human C3a des Arg also binds to guinea pig platelets, but Scatchard analysis indicated that no specific binding occurred. Because the ligand-binding studies were complicated by high levels of nonspecific uptake, we attempted to chemically cross-link the C3a molecule to a specific component on the platelet surface. Cross-linkage of 125I-C3a to guinea pig platelets with bis(sulfosuccinimidyl)suberate revealed radioactive complexes at 105,000 and 115,000 m.w. on SDS-PAGE gels by autoradiographic analysis. In the presence of excess unlabeled C3a, complex formation was inhibited. No cross-linkage could be demonstrated between the inactive 125I-C3a des Arg and the putative C3a-R on guinea pig platelets. Human C3a, but not C3a des Arg induces serotonin release and aggregation of the guinea pig platelets. Human C3a was unable to induce either serotonin release or promote aggregation of human platelets. Uptake of human 125I-C3a by human platelets was not saturable, and Scatchard analysis was inconclusive. Attempts to cross-link 125I-C3a to components on the surface of human platelets also failed to reveal a ligand-receptor complex. Therefore, we conclude that guinea pig platelets have specific surface receptors to C3a and that human platelets appear devoid of receptors to the anaphylatoxin.

  17. The OARSI Histopathology Initiative - Recommendations for Histological Assessments of Osteoarthritis in the Guinea Pig

    PubMed Central

    Kraus, Virginia B; Huebner, Janet L.; DeGroot, Jeroen; Bendele, Alison

    2010-01-01

    Objective This review focuses on the criteria for assessing osteoarthritis (OA) in the guinea pig at the macroscopic and microscopic levels, and recommends particular assessment criteria to assist standardization in the conduct and reporting of preclinical trails in guinea pig models of OA. Methods A review was conducted of all OA studies from 1958 until the present that utilized the guinea pig. The PubMed database was originally searched August 1, 2006 using the following search terms: guinea pig and osteoarthritis. We continued to check the database periodically throughout the process of preparing this chapter and the final search was conducted January 7, 2009. Additional studies were found in a review of abstracts from the OsteoArthritis Research Society International (OARSI) conferences, Orthopaedic Research Society (ORS) conferences, and literature related to histology in other preclinical models of OA reviewed for relevant references. Studies that described or used systems for guinea pig joint scoring on a macroscopic, microscopic, or ultrastructural basis were included in the final comprehensive summary and review. General recommendations regarding methods of OA assessment in the guinea pig were derived on the basis of a comparison across studies and an inter-rater reliability assessment of the recommended scoring system. Results A histochemical-histological scoring system (based on one first introduced by H. Mankin) is recommended for semi-quantitative histological assessment of OA in the guinea pig, due to its already widespread adoption, ease of use, similarity to scoring systems used for OA in humans, its achievable high inter-rater reliability, and its demonstrated correlation with synovial fluid biomarker concentrations. Specific recommendations are also provided for histological scoring of synovitis and scoring of macroscopic lesions of OA. Conclusions As summarized herein, a wealth of tools exist to aid both in the semi-quantitative and quantitative

  18. Natural antibodies to treponemal antigens in four strains of guinea-pigs.

    PubMed Central

    Jakubowski, A; Wicher, V; Gruhn, R; Wicher, K

    1987-01-01

    A total of 185 serum samples obtained from healthy male and female guinea-pigs of inbred strains 2 and 13 and outbred strains C4D and Hartley A were examined for natural antibodies to treponemal antigens by ELISA using Treponema pallidum (TP), T. phagedenis biotype Reiter (TR) and T. vincentii (TV) antigens and by the FTA test. The prevalence and titres of natural antibodies depended on the age and strain of guinea-pig and the treponemal antigen used. One- and 7-day-old guinea-pigs contained significantly (P less than 0.001) higher levels of natural antibodies than did animals 1 or 3-6 months old. The similar high levels of natural antibodies in newborn guinea-pigs and their mothers (12-30 months old) and the sharp drop observed at the age of 1 month suggested maternal transfer as the mechanism of acquisition. In young adults 3-6 months old, the age group most susceptible to TP infection, antibodies to TP and TR were at their lowest levels, but antibodies reacting to TV had already begun to rise. Natural antibodies were of the IgG1 and IgG2 but not of the IgM class. The highest levels of natural antibodies were in the C4D guinea-pigs; the lowest were in the Hartley A strain. Natural antibody activity was inhibited or adsorbed by TR antigens. PMID:3546103

  19. Congenital malformations caused by Stryphnodendron fissuratum (Leg. Mimosoideae) in guinea pigs (Cavia porcellus).

    PubMed

    Macedo, Josenaldo S; Rocha, Brena P; Colodel, Edson M; Freitas, Sílvio H; Dória, Renata G S; Riet-Correa, Franklin; Evêncio-Neto, Joaquim; Mendonça, Fábio S

    2015-11-01

    The aim of this study was to evaluate the toxicity of Stryphnodendron fissuratum pods in guinea pigs (Cavia porcellus) and test the hypothesis that this plant has teratogenic effects. Thus, sixteen guinea pigs were randomly divided into four groups of four animals each. Groups 10, 20 and 40 consisted of guinea pigs that received commercial food that contained crushed pods of S. fissuratum at concentrations of 10, 20 and 40 g/kg, respectively, during the period of organogenesis. Control group consisted of guinea pigs under the same management conditions that did not receive crushed pods of S. fissuratum in their food. In all experimental groups, the main clinical signs of poisoning consisted of anorexia, prostration, absence of vocalizations, alopecia, diarrhea, and abortions within the adult guinea pigs. Those that did not abort gave birth to weak, malnourished pups, some of which had fetal malformations. The main teratogenic changes consisted of eventration, arthrogryposis, amelia of the forelimbs, anophthalmia, microphthalmia, anotia and agnathia. The reductions in the number of offspring and the malformations observed in the experimental groups suggest that S. fissuratum affects fetal development and is teratogenic. PMID:26363291

  20. Late effects of radiation on the lumbar spinal cord of guinea pigs: Re-treatment tolerance

    SciTech Connect

    Mason, K.A. ); Withers, H.R.; Chiang, Chi-Shiun )

    1993-07-15

    Using a guinea pig model of lumbar myelopathy, various factors affecting the tolerance of spinal cord to irradiation were assessed: (a) extent of initial injury; (b) time interval between priming and test doses; and (c) animal age at the time of initial radiation treatment. A 3 cm section of lumbar spinal cord of guinea pigs was irradiated with fractionated doses of 4.5 Gy gamma rays given as 9 fractions per week. Guinea pigs were primed with 9 x 4.5 Gy in 7 days which is 60% of the ED[sub 50] for a continuous course of treatment. After 28 or 40 weeks, animal were retreated with 6-14 fractions of 4.5 Gy. Animals were observed for 2 years following the priming dose and both the incidence and latency of myelopathy recorded. Young adult guinea pigs (8 wk old) showed both a decreased radiation tolerance and latency compared to old individuals (40 wk old). At 28 or 40 wk after 9 x 4.5 Gy, only about 8% of the initial injury was remembered in young adult guinea pigs. The amount of residual injury was dependent on the initial damage as a proportion of the tolerance dose. The spinal cord shows a greater capacity for long-term recovery than generally appreciated and re-treatment doses clinically prescribed may be lower than necessary. 8 refs., 3 figs., 2 tabs.

  1. Reduced noise susceptibility in littermate offspring from heterozygous animals of the German waltzing guinea pig.

    PubMed

    Skjönsberg, Åsa; Mannström, Paula

    2015-07-01

    The German waltzing guinea pig is a spontaneously mutated strain with severe auditory and vestibular impairment caused by a so far unknown genetic mutation. The animals are born deaf and show a circling behavior. The heterozygote animals of this guinea pig strain have functionally normal hearing and balance. However, these animals have, in earlier studies, shown an increased resistance to noise compared with normal wild-type guinea pigs. In the present study, we explored the functional hearing with auditory brainstem response thresholds before and at different time points after noise exposure. Symptom-free littermates from heterozygote couples of the German waltzing guinea pigs were exclusively used for the study, which, after the hearing test, were sent back for breeding to confirm their genotype (i.e. heterozygote or normal). The aim of this paper was to ascertain that the previously shown reduced susceptibility to noise trauma in the heterozygote animals of the German waltzing guinea pig was also evident when littermates were used as control animals. The findings are important for further analysis of the heterozygote animals of this strain and for future investigations of the underlying mechanisms behind the diverse susceptibility to exposures of loud sound. PMID:26053702

  2. Dual action (stimulation, inhibition) of D600 on contractility and calcium channels in guinea-pig and cat heart cells.

    PubMed Central

    McDonald, T; Pelzer, D; Trautwein, W

    1989-01-01

    1. We examined the effects of D600 (0.2-40 microM, generally 2 microM) on the following (i) developed tension in guinea-pig papillary muscles, (ii) calcium current (Ica) and tension in cat ventricular muscle strands, (iii) Ica in guinea-pig and cat ventricular myocytes, (iv) single Ca2+ channel currents carried by Ba2+ in cell-attached membrane patches of guinea-pig ventricular myocytes, and (v) Ba2+ currents through dihydropyridine (DHP)-binding sites (skeletal muscle) reconstituted into single functional Ca2+ channels in lipid bilayers. 2. In 27 of 140 preparations studied, D600 elicited a transient stimulation that preceded marked inhibition. The stimulation was normally of short duration (less than 5 min) and moderate strength (less than 50% increase). 3. D600 had no effect on the unit conductance of single cardiac Ca2+ channels. Stimulation was characterized by a decrease in the number of records with no openings (blanks) and an increase in the open-state probability of non-blanks (longer open times, shorter closed times). Inhibition began with an increase in the number of blanks and later included a curtailment of open times and a prolongation of closed times. The net effect after 9 min D600 was a 75% reduction in average current amplitude. 4. A similar pattern of changes in channel open and closed times produced enhancement and then depression of time-averaged open-state probability in single reconstituted channels. 5. Single Ca2+ channel current that was stimulated by adrenaline was only slightly depressed after 2 microM-D600 for 30 min. It may be that channel phosphorylation or Gs-protein activation following beta-receptor stimulation reduces channel affinity for D600. 6. Short-lived binding of D600 to a single inhibitory site may enhance association/activation of Gs-protein and thereby cause transient up-regulation prior to increased drug occupancy and inhibition. Alternatively, there may be separate stimulatory and inhibitory sites. One aspect of

  3. Spot-on Treatments of Diflubenzuron and Permethrin to Control a Guinea Pig Louse, Gliricola Porcelli (Phthiraptera: Gyropidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Guinea pigs (Cavia porcellus (L.)) (Rodentia: Caviidae) are pets and laboratory animals. They can be infested by a chewing louse, Gliricola porcelli (Schrank) (Phthiraptera: Gyropidae), which is fairly common in some animal rearing facilities, pet stores, and on wild guinea pigs. Infestation with G....

  4. Protective effects of fluvoxamine against ischemia/reperfusion injury in isolated, perfused guinea-pig hearts.

    PubMed

    Muto, Tatsuya; Usuda, Haruki; Yamamura, Aya; Yoshida, Koji; Ohashi, Ai; Mitsui-Saitoh, Kumiko; Sakai, Junichi; Sugimoto, Yumi; Mizutani, Hideki; Nonogaki, Tsunemasa; Hotta, Yoshihiro

    2014-01-01

    Serotonin (5-hydroxytryptamine; 5-HT) is known to be activated during ischemia-reperfusion and triggers contractile dysfunction and pathological apoptosis. Here, the beneficial effects of the selective serotonin reuptake inhibitor (SSRI) fluvoxamine was demonstrated on ischemia-reperfusion injury in guinea-pig hearts perfused using the Langendorff technique. The recovery (%) of left ventricular developed pressure (LVDP) by fluvoxamine (5×10(-8) M) was 95.4% (control: 32%), which was consistent with the inhibition of mitochondrial Ca(2+)([Ca(2+)]m) uptake induced by changes in the Ca(2+) content and acidification of the perfusate, and similar to reperfusion following global ischemia in Langendorff-perfused hearts. Fluvoxamine inhibited the increase in [Ca(2+)]m induced by changes in the Ca(2+) content of the perfusate in perfused preparations of mitochondria, which was similar to the results obtained with the mitochondrial permeability transition pore (MPTP) opener atractyroside. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL)-positive cells were significantly less in fluvoxamine-treated hearts than in control hearts, with decreases in caspase-3 activity. These results suggest that SSRI inhibits opening of the MPTP by preventing [Ca(2+)]m overload-induced apoptosis related to the endogenous accumulation of 5-HT in ischemia-reperfusion hearts. PMID:24789996

  5. β2 adrenergic receptor activation governs cardiac repolarization and arrhythmogenesis in a guinea pig model of heart failure

    PubMed Central

    Wang, Yao; Yuan, Jiamin; Qian, Zhiyong; Zhang, Xiwen; Chen, Yanhong; Hou, Xiaofeng; Zou, Jiangang

    2015-01-01

    β2-AR activation increases the risk of sudden cardiac death (SCD) in heart failure (HF) patients. Non-selective β-AR blockers have greater benefits on survival than selective β1-AR blockers in chronic HF patients, indicating that β2-AR activation contributes to SCD in HF. This study investigated the role of β2-AR activation on repolarization and ventricular arrhythmia (VA) in the experimental HF model. The guinea pig HF was induced by descending aortic banding. The effective refractoriness period (ERP), corrected QT (QTc) and the incidence of VA were examined using Langendorff and programmed electrical stimulation. Ikr and APD were recorded by the whole cell patch clamp. Selective β2-AR agonist salbutamol significantly increased the incidence of VA, prolonged QTc and shortened ERP. These effects could be prevented by the selective β2-AR antagonist, ICI118551. Salbutamol prolonged APD90 and reduced Ikr in guinea pig HF myocytes. The antagonists of cAMP (Rp-cAMP) and PKA (KT5720) attenuated Ikr inhibition and APD prolongation induced by salbutamol. However, the antagonists of Gi protein (PTX) and PDE III (amrinone) showed opposite effects. This study indicates that β2-AR activation increases the incidence of VA in the experimental HF model via activation of Gs/cAMP/PKA and/or inhibition of Gi/PDE pathways. PMID:25567365

  6. Halothane inhibits calcium accumulation following myocardial ischemia and calcium paradox in guinea pig hearts

    SciTech Connect

    Hoka, S.; Bosnjak, Z.J.; Kampine, J.P.

    1987-08-01

    This study was performed to test the hypothesis that halothane inhibits calcium accumulation associated with myocardial ischemia and calcium paradox. Using a Langendorff preparation in isolated guinea pig hearts, tissue /sup 45/Ca was measured after 40 and 60 min of loading with /sup 45/Ca, followed by 20 min of washout period. Myocardial ischemia was produced by a 30-min occlusion of the left anterior descending coronary artery (LAD). LAD occlusion caused an increase in /sup 45/Ca content in the anterior left ventricular muscle (ischemic area) of 215% compared to that of the posterior left ventricular muscle (normal myocardium). The increase in /sup 45/Ca content in the ischemic area was significantly less (P less than 0.05) in the presence of halothane (1%) compared to the non-halothane group. Halothane did not significantly alter /sup 45/Ca content in the non-ischemic myocardium. Myocardial injury associated with calcium paradox, which was produced by a 10-min perfusion of the heart with calcium-free Krebs solution followed by normal calcium repletion, caused a significant increase (P less than 0.05) in the /sup 45/Ca content compared to control. Addition of halothane (1%) significantly depressed (P less than 0.05) the increase in /sup 45/Ca content caused by calcium paradox. It is suggested that halothane might inhibit calcium accumulation associated with myocardial ischemia and calcium paradox under certain experimental situations. The inhibitory effect of halothane on calcium accumulation may be beneficial for the ischemic heart during halothane anesthesia.

  7. Disodium cromoglycate prevents ileum hyperreactivity to histamine in Toxocara canis-infected guinea pigs.

    PubMed

    Sá-Nunes, A; Corrado, A P; Baruffi, M D; Faccioli, L H

    2003-11-01

    The aim of this study was to investigate whether Toxocara canis infection in guinea pigs provokes changes in ileum responsiveness to histamine. Ileum segments from control and T. canis-infected groups were placed at isometric conditions and submitted to various doses of histamine. No changes were observed between controls and T. canis-infected groups at days 3, 6 and 12 after infection. However, at days 18 and 24 after infection, there was a significant increase in ileum responsiveness to histamine in T. canis-infected group. Pre-incubation of ileum segments with 1mgml(-1) disodium cromoglycate (DSCG) prevented the increased responsiveness to histamine in T. canis-infected guinea pigs and did not affect ileum contractility in non-infected animals. These results indicate that T. canis-infected guinea pigs develop increased intestinal responsiveness to histamine and that DSCG prevents alterations in smooth-muscle contractility. PMID:12967589

  8. Differences in susceptibility to infection with Treponema pallidum (Nichols) between five strains of guinea pig.

    PubMed

    Wicher, K; Wicher, V; Gruhn, R F

    1985-02-01

    Groups of 10 young male guinea pigs of inbred strains 2 and 13 and outbred strains Hartley A, Hartley B, and one deficient in the fourth component of complement (C4D) were infected intradermally with 80 X 10(6) Treponema pallidum (Nichols). The course of infection and production of antitreponemal antibody were examined. Strain C4D guinea pigs were the most susceptible to infection (100%); inbred strains 2 and 13 and outbred strain Hartley B showed 80-90% symptomatic infection; and the Hartley A strain was the least susceptible to infection (10%). Strain 13 animals responded with the highest antitreponemal antibody activity, and the Hartley A strain with the lowest. The results suggest that genetic factors or complement, or both, may influence the degree of susceptibility to infection with T pallidum in guinea pigs. PMID:3910539

  9. The release of histamine by parasympathetic stimulation in guinea-pig auricle and rat ileum.

    PubMed Central

    Bani-Sacchi, T; Barattini, M; Bianchi, S; Blandina, P; Brunelleschi, S; Fantozzi, R; Mannaioni, P F; Masini, E

    1986-01-01

    Two preparations, a segment of rat ileum and the vagally innerved guinea-pig auricles, have been used in an analysis of the responses to vagal or to electrical field stimulation. The responses to parasympathetic stimulation were depressed by atropine and by tetrodotoxin, and potentiated by eserine. Supramaximal stimulation (10-20 Hz) resulted in increased release of acetylcholine and histamine, both in rat ileum and guinea-pig auricles. The release of histamine after parasympathetic stimulation did not exhibit tachyphylaxis, and it was not reproduced by non-parasympathetic stimuli. In both preparations, atropine produced a significant, dose-related reduction of histamine measured in the bath fluid after stimulation, while eserine increased histamine output. A significant diminution of mast cell granules metachromasia was observed in guinea-pig auricles and in rat intestine after parasympathetic stimulation. The possibility is discussed that acetylcholine released by parasympathetic stimulation would in turn evoke the secretion of histamine from tissue mast cells. PMID:2422351

  10. Comparative study of 2 surgical techniques for castration of guinea pigs (Cavia porcellus)

    PubMed Central

    Guilmette, Josée; Langlois, Isabelle; Hélie, Pierre; de Oliveira El Warrak, Alexander

    2015-01-01

    The objective of this study was to compare 2 surgical approaches (scrotal or abdominal) for castration of guinea pigs and to investigate post-operative infection rates with either technique. Forty-eight guinea pigs were castrated by scrotal or abdominal technique after being randomly assigned to 1 of 2 groups (n = 24). Individuals were either castrated by an experienced exotic animal surgeon (n = 12) or by an experienced small animal surgeon (n = 12). Surgical wounds were evaluated daily before euthanasia for histological evaluation 2 wks after surgery. Post-operative infection rate was significantly higher in the scrotal group than in the abdominal group, with a higher rate for the experienced small animal surgeon. Castration of guinea pigs with the abdominal technique is significantly faster and has a significantly lower post-operative infection rate than the scrotal technique. PMID:26424914

  11. Inhibition of gastric secretion in guinea pig by relatively low dose ionizing radiation

    SciTech Connect

    Batzri, S.; Catravas, G.

    1988-11-01

    We evaluated the effect of a single dose of ionizing radiation on gastric secretion in awake guinea pigs equipped with a permanent gastric cannula. Changes in gastric secretion were measured using a dye dilution technique. Infusion of histamine increased acid and fluid output and there was a positive correlation (r = 0.93) between the two. Total body irradiation with 400 cGy, like cimetidine, suppressed acid and fluid secretion under basal conditions and during histamine stimulation by 50-90%. Recovery from the radiation damage was only partial after one week. Irradiation inhibited the rise in gastric juice volume during histamine stimulation and also reduced the normal gain in body weight of the guinea pig. These results demonstrate that ionizing radiations have an immediate and long lasting effects on the gastric mucosal function of the guinea pig.

  12. Pathological and virological features of arenavirus disease in guinea pigs. Comparison of two Pichinde virus strains.

    PubMed Central

    Aronson, J. F.; Herzog, N. K.; Jerrells, T. R.

    1994-01-01

    A guinea pig passage-adapted strain of the arena-virus Pichinde (adPIC) is highly virulent in inbred guinea pigs, whereas the related strain PIC3739 is attenuated. Both viruses were macrophage tropic and infected peritoneal, splenic, liver, and alveolar macrophages during experimental Pichinde virus infection. Infection with the virulent strain was associated with unlimited viral replication in the face of exaggerated delayed-type hypersensitivity response, manifested by the macrophage disappearance reaction. Histopathological lesions unique to adPIC-infected guinea pigs included intestinal villus blunting with mucosal infiltration by pyknotic debris-laden macrophages and apoptosis of crypt epithelial cells. Splenic red pulp necrosis was also significantly associated with adPIC infection but not PIC3739 infection. These findings may provide clues to the pathogenesis of a group of poorly understood human viral hemorrhagic fevers. Images Figure 6 Figure 7 PMID:8030751

  13. Species differences in the localization and number of CNS beta adrenergic receptors: Rat versus guinea pig

    SciTech Connect

    Booze, R.M.; Crisostomo, E.A.; Davis, J.N.

    1989-06-01

    The localization and number of beta adrenergic receptors were directly compared in the brains of rats and guinea pigs. The time course of association and saturability of (125I)cyanopindolol (CYP) binding to slide-mounted tissue sections was similar in rats (Kd = 17 pM) and guinea pigs (Kd = 20 pM). The beta-1 and beta-2 receptor subtypes were examined through the use of highly selective unlabeled receptor antagonists, ICI 118,551 (50 nM) and ICI 89,406 (70 nM). Dramatic species differences between rats and guinea pigs were observed in the neuroanatomical regional localization of the beta adrenergic receptor subtypes. For example, in the thalamus prominent beta-1 and beta-2 receptor populations were identified in the rat; however, the entire thalamus of the guinea pig had few, if any, beta adrenergic receptors of either subtype. Hippocampal area CA1 had high levels of beta-2 adrenergic receptors in both rats and guinea pigs but was accompanied by a widespread distribution of beta-2 adrenergic receptors only in rats. Quantitative autoradiographic analyses of 25 selected neuroanatomical regions (1) confirmed the qualitative differences in CNS beta adrenergic receptor localization, (2) determined that guinea pigs had significantly lower levels of beta adrenergic receptors than rats and (3) indicated a differential pattern of receptor subtypes between the two species. Knowledge of species differences in receptor patterns may be useful in designing effective experiments as well as in exploring the relationships between receptor and innervation patterns. Collectively, these data suggest caution be used in extrapolation of the relationships of neurotransmitters and receptors from studies of a single species.

  14. Adenosine transport systems on dissociated brain cells from mouse, guinea-pig, and rat

    SciTech Connect

    Johnston, M.E.; Geiger, J.D. )

    1990-09-01

    The kinetics and sodium dependence of adenosine transport were determined using an inhibitor-stop method on dissociated cell body preparations obtained from mouse, guinea-pig and rat brain. Transport affinity (KT) values for the high affinity adenosine transport systems KT(H) were significantly different between these three species; mean +/- SEM values were 0.34 +/- 0.1 in mouse, 0.9 +/- 0.2 in rat, and 1.5 +/- 0.5 microM in guinea-pig. The KT values for the low affinity transport system KT(L) were not different between the three species. Brain cells from rat displayed a significantly greater maximal capacity to accumulate (3H)adenosine (Vmax) than did mouse or guinea-pig for the high affinity system, or than did mouse for the low affinity system. When sodium chloride was replaced in the transport medium with choline chloride, the KT(H) values for guinea-pig and rat were both increased by approximately 100%; only in rat did the change reach statistical significance. The sodium-dependence of adenosine transport in mouse brain was clearly absent. The differences between KT(H) values in mouse and those in guinea-pig or rat were accentuated in the absence of sodium. The differences in kinetic values, ionic requirements, and pharmacological characteristics between adenosine transporters in CNS tissues of mouse, guinea-pig and rat may help account for some of the variability noted among species in terms of their physiological responses to adenosine.

  15. Rifapentine Is Not More Active than Rifampin against Chronic Tuberculosis in Guinea Pigs

    PubMed Central

    Dutta, Noton K.; Illei, Peter B.; Peloquin, Charles A.; Pinn, Michael L.; Mdluli, Khisimuzi E.; Nuermberger, Eric L.; Grosset, Jacques H.

    2012-01-01

    Rifamycins are key sterilizing drugs in the current treatment of active tuberculosis (TB). Daily dosing of rifapentine (P), a potent rifamycin with high intracellular accumulation, in place of rifampin (R) in the standard antitubercular regimen significantly shortens the duration of treatment needed to prevent relapse in a murine model of active TB. We undertook the current study to compare directly the activities of human-equivalent doses of P and R in a guinea pig model of chronic TB, in which bacilli are predominantly extracellular within human-like necrotic granulomas. Hartley strain guinea pigs were aerosol infected with ∼200 bacilli of Mycobacterium tuberculosis H37Rv, and treatment given 5 days/week was initiated 6 weeks later. R at 100 mg/kg of body weight and P at 100 mg/kg were given orally alone or in combination with isoniazid (H) at 60 mg/kg and pyrazinamide (Z) at 300 mg/kg. Culture-positive relapse was assessed in subgroups of guinea pigs after completion of 1 and 2 months of treatment. Human-equivalent doses of R and P showed equivalent bactericidal activity when used alone and in combination therapy. In guinea pigs treated with rifampin, isoniazid, and pyrazinamide (RHZ) or PHZ, microbiological relapse occurred in the lungs of 8/10 animals treated for 1 month and in 0/10 animals treated for 2 months. Substitution of P for R in the standard antitubercular regimen did not shorten the time to cure in this guinea pig model of chronic TB. Data from ongoing clinical trials comparing the activity of these two drugs are awaited to determine the relevance of the guinea pig TB model in preclinical drug screening. PMID:22547623

  16. Conjugated linoleic acid mitigates testosterone-related changes in body composition in male guinea pigs.

    PubMed

    Yang, Susan Q; DeGuire, Jason R; Lavery, Paula; Mak, Ivy L; Weiler, Hope A; Santosa, Sylvia

    2016-05-01

    We hypothesize that conjugated linoleic acid (CLA) may be effective in preventing the changes in total and regional body composition and increases in interleukin (IL) 6 that occur as a result of hypogonadism. Male guinea pigs (n = 40, 70- to 72-week retired breeders) were block randomized by weight into 4 groups: (1) sham surgery (SHAM)/control (CTRL) diet, (2) SHAM/conjugated linoleic acid (CLA) diet (1%), (3) orchidectomy (ORX)/CTRL diet, and (4) ORX/CLA diet. Dual-energy x-ray absorptiometry scans were performed at baseline and week 16 to assess body composition. Serum IL-6 was analyzed using an enzyme-linked immune sorbent assay. Fatty acids (FAs) from visceral and subcutaneous adipose tissue were analyzed using gas chromatography. In ORX/CTRL guinea pigs, percent total body fat increased by 6.1%, and percent lean mass decreased by 6.7% over the 16-week treatment period, whereas no changes were observed for either parameter in ORX/CLA guinea pigs. Guinea pigs fed the CLA diet gained less percent total, upper, and lower body fat than those fed the CTRL diet regardless of surgical treatment. Regional adipose tissue FA composition was reflective of dietary FAs. Serum IL-6 concentrations were not different among groups. In this study, we observed that, in male guinea pigs, hypogonadism resulted in increased fat mass and decreased lean mass. In addition, CLA was effective in reducing gains in body fat and maintaining lean mass in both hypogonadal and intact guinea pigs. PMID:27101759

  17. Differences in the distribution and characteristics of tachykinin NK1 binding sites between human and guinea pig lung.

    PubMed Central

    Walsh, D A; Salmon, M; Featherstone, R; Wharton, J; Church, M K; Polak, J M

    1994-01-01

    1. The distribution and characteristics of tachykinin NK1 binding sites have been compared in human and guinea pig lung using quantitative in vitro receptor autoradiography with [125I]-Bolton Hunter-labelled substance P ([125I]-BH-SP). In addition, the effects on these sites of ovalbumin sensitization and challenge have been determined in guinea pig lung. 2. [125I]-BH-SP bound specifically and with high affinity to microvascular endothelium in both human and guinea pig lung, but to bronchial smooth muscle and pulmonary artery media in only guinea pig lung. 3. Specific binding of [125I]-BH-SP to guinea pig bronchial smooth muscle was positively correlated with airway diameter in the range 150-800 microns and was less dense in trachea than in main bronchi. 4. [125I]-BH-SP binding was inhibited by tachykinins with rank orders of affinity of SP > NKA > NKB (human microvessels) and SP > NKA = NKB (guinea pig bronchi and pulmonary arteries). NKA displayed a higher affinity for [125I]-BH-SP binding sites in human microvessels than in guinea pig tissues (P < 0.0001), indicating differences in selectivity for tachykinins between human and guinea pig NK1 receptors. 5. In both human and guinea pig lung, [125I]-BH-SP binding was inhibited by the specific tachykinin receptor antagonists FK888 (NK1 selective antagonist) and FK224 (mixed NK1/NK2 antagonist), with FK888 displaying equal affinity to SP and > 500 times higher affinity than FK224. SP, NKA, NKB and FK888 exhibited similar affinities for [125I]-BH-SP binding sites in both guinea pig arteries and bronchi.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 1 Figure 2 PMID:7534186

  18. Apparent lack of beta 3-adrenoceptors and of insulin regulation of glucose transport in brown adipose tissue of guinea pigs.

    PubMed

    Himms-Hagen, J; Triandafillou, J; Begin-Heick, N; Ghorbani, M; Kates, A L

    1995-01-01

    Norepinephrine-induced thermogenesis was substantial in adipocytes from brown adipose tissue (BAT) of cold-acclimated guinea pigs but absent in adipocytes from BAT of warm-acclimated guinea pigs. There was no thermogenic response to any beta 3-adrenergic agonist (CL-316,243, ZD-7114, BRL-28410, CGP-12177). The receptor was characterized as a beta 1-adrenoceptor. Adrenergic agonists stimulated adenylate cyclase in membranes from BAT of both warm- and cold-acclimated guinea pigs also via a beta 1-adrenoceptor; beta 3-adrenergic agonists had no effect. Glucose transport by brown adipocytes from warm-acclimated guinea pigs was not stimulated by either norepinephrine or insulin. Cold acclimation induced the appearance of stimulation of glucose transport by norepinephrine in association with the appearance of a large capacity for thermogenesis, but there was little improvement in response to insulin. GLUT4 was present in membranes from BAT of both warm- and cold-acclimated guinea pigs. Insulin is known to have an antilipolytic effect on both BAT and white adipose tissue of guinea pigs. Thus there is a selective lack of insulin-regulated glucose transport that is not improved by cold acclimation. Guinea pigs may have a mutated component of the translocation mechanism for GLUT4. beta 3-Adrenoceptors appear to be absent in brown adipocytes of adult guinea pigs, as in white adipocytes of guinea pigs, yet are known to be present in the gut. Tissue-specific expression of beta 3-adrenergic receptors in guinea pigs may differ from that in rats, in which receptors are expressed in the adipose tissues and gut. PMID:7840345

  19. Bradykinin-induced contraction of guinea pig lung in vitro.

    PubMed

    Lach, E; Trifilieff, A; Mousli, M; Landry, Y; Gies, J P

    1994-08-01

    We have investigated the contractile effect of bradykinin (BK) in guinea pig lung in vitro. BK induces a dose-related contraction of lung parenchymal strips which is increased significantly in the presence of 10(-5) M captopril (an angiotensin converting enzyme inhibitor) or 10(-5) M DL-thiorphan (a neutral endopeptidase inhibitor). The kininase I inhibitor, DL-2-mercaptomethyl-3-guanidino-ethylthiopropionic acid (MGTPA), has no effect on the BK-induced contraction. BK is more potent in contracting parenchymal lung strips than other contractile agents (histamine, carbachol and substance P), however the BK-induced maximal contraction is lower than those obtained with histamine and carbachol. The B1 agonist, des-Arg9-BK, does not contract lung parenchymal strips. The new BK B2 receptor antagonists (Hoe 140, NPC 17731 and NPC 17761), which possess binding affinities in the nanomolar range, inhibit the BK-induced contractile response in a dose-dependent manner. The BK-induced contraction was unaffected by propranolol, atropine, tetrodotoxin, capsaicin pre-treatment, triprolidine, methysergide, Ro 19-3704 and N omega-nitro-L-arginine-methyl-ester (L-NAME), excluding the involvement of nervous pathways, preformed mast cell mediators, platelet-activating factor and nitric oxide. However, indomethacin, a cyclooxygenase inhibitor, AA-861, a 5-lipoxygenase inhibitor, and furegrelate, a thromboxane A2 synthase inhibitor, decreased the contractile response to BK, suggesting that both cyclooxygenase and 5-lipoxygenase products are involved in this contraction.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7990978

  20. The sensitizing capacity of multifunctional acrylates in the guinea pig.

    PubMed

    Björkner, B

    1984-10-01

    The multifunctional acrylates used in ultraviolet (UV) curable resins act as cross-linkers and "diluents". They are usually based on di(meth)acrylate esters of dialcohols or tri- and tetra-acrylate esters of polyalcohols. In UV-curable coatings, the most commonly used are pentaerythritol triacrylate (PETA), trimethylolpropane triacrylate (TMPTA) and 1,6-hexanediol diacrylate (HDDA). In other uses, such as dental composite resin materials, the dimethacrylic monomers based on n-ethylene glycol are the most useful. The sensitizing capacity of various multifunctional acrylates and their cross-reactivity pattern have been investigated with the guinea pig maximization test. The tests show that BUDA (1,4-butanediol diacrylate) and HDDA are moderate to strong sensitizers and that they probably cross-react with each other. The n-ethylene glycol diacrylates and methacrylates tested are weak or non-sensitizers. Tripropylene glycol diacrylate (TPGDA) is a moderate and neopentyl glycol diacrylate (NPGDA) a strong sensitizer, whereas neopentyl glycol dimethacrylate is a non-sensitizer. The commercial PETA is a mixture of pentaerythritol tri- and tetra-acrylate (PETA-3 and PETA-4). PETA-3 is a much stronger sensitizer than PETA-4. Simultaneous reactions were seen between PETA-3, PETA-4 and TMPTA. The oligotriacrylate OTA 480 is a moderate sensitizer, but no concomitant reactions were seen with PETA-3, PETA-4 or TMPTA. Of the multifunctional acrylates tested, the di- and triacrylic compounds should be regarded as potent sensitizers. The methacrylated multifunctional acrylic compounds are weak or non-sensitizers. PMID:6499426

  1. Pharmacometabolomic Approach to Predict QT Prolongation in Guinea Pigs

    PubMed Central

    Lee, Hae Won; Lim, Mi-sun; Seong, Sook Jin; Seo, Jeong Ju; Kim, Eun-Jung; Kang, Wonku; Yoon, Young-Ran

    2013-01-01

    Drug-induced torsades de pointes (TdP), a life-threatening arrhythmia associated with prolongation of the QT interval, has been a significant reason for withdrawal of several medicines from the market. Prolongation of the QT interval is considered as the best biomarker for predicting the torsadogenic risk of a new chemical entity. Because of the difficulty assessing the risk for TdP during drug development, we evaluated the metabolic phenotype for predicting QT prolongation induced by sparfloxacin, and elucidated the metabolic pathway related to the QT prolongation. We performed electrocardiography analysis and liquid chromatography–mass spectroscopy-based metabolic profiling of plasma samples obtained from 15 guinea pigs after administration of sparfloxacin at doses of 33.3, 100, and 300 mg/kg. Principal component analysis and partial least squares modelling were conducted to select the metabolites that substantially contributed to the prediction of QT prolongation. QTc increased significantly with increasing dose (r = 0.93). From the PLS analysis, the key metabolites that showed the highest variable importance in the projection values (>1.5) were selected, identified, and used to determine the metabolic network. In particular, cytidine-5′-diphosphate (CDP), deoxycorticosterone, L-aspartic acid and stearic acid were found to be final metabolomic phenotypes for the prediction of QT prolongation. Metabolomic phenotypes for predicting drug-induced QT prolongation of sparfloxacin were developed and can be applied to cardiac toxicity screening of other drugs. In addition, this integrative pharmacometabolomic approach would serve as a good tool for predicting pharmacodynamic or toxicological effects caused by changes in dose. PMID:23593245

  2. Beam-Beam Interaction Simulations with Guinea Pig (LCC-0125)

    SciTech Connect

    Sramek, C

    2003-11-20

    At the interaction point of a particle accelerator, various phenomena occur which are known as beam-beam effects. Incident bunches of electrons (or positrons) experience strong electromagnetic fields from the opposing bunches, which leads to electron deflection, beamstrahlung and the creation of electron/positron pairs and hadrons due to two-photon exchange. In addition, the beams experience a ''pinch effect'' which focuses each beam and results in either a reduction or expansion of their vertical size. Finally, if a beam's disruption parameter is too large, the beam can develop a sinusoidal distortion, or two-stream (kink) instability. This project simulated and studied these effects as they relate to luminosity, deflection angles and energy loss in order to optimize beam parameters for the Next Linear Collider (NLC). Using the simulation program Guinea Pig, luminosity, deflection angle and beam energy data was acquired for different levels of beam offset and distortion. Standard deflection curves and luminosity plots agreed with theoretical models but also made clear the difficulties of e-e- feedback. Simulations emphasizing kink instability in modulated and straight beam collisions followed qualitative behavioral predictions and roughly fit recent analytic calculations. A study of e-e- collisions under design constraints for the NLC provided new estimates of how luminosity, beamstrahlung energy loss, upsilon parameter and deflection curve width scale with beam cross-sections ({sigma}{sub x}, {sigma}{sub y}, {sigma}{sub z}) and number of particles per bunch (N). Finally, this same study revealed luminosity maxima at large N and small {sigma}{sub y} which may merit further investigation.

  3. Purification and characterization of guinea pig liver morphine 6-dehydrogenase.

    PubMed

    Yamano, S; Kageura, E; Ishida, T; Toki, S

    1985-05-10

    Morphine 6-dehydrogenase, which catalyzes the dehydrogenation of morphine to morphinone, has been purified about 440-fold from the soluble fraction of guinea pig liver with a yield of 38%. The purified enzyme was a homogeneous protein on polyacrylamide gel disc electrophoresis and isoelectric focusing. The molecular weight and isoelectric point of the enzyme were 29,000 and 7.6, respectively. The enzyme utilizes both NAD and NADP as a cofactor, and the Km values were 0.12 mM for NAD and 0.42 mM for NADP. The Vmax values for morphine were 588 milliunits/mg of protein (with NAD) and 1600 milliunits/mg of protein (with NADP). The Km values for morphine were 0.12 mM (with NAD) and 0.49 mM (with NADP). The enzyme also exhibited activity for morphine-related compounds: nalorphine, normorphine, codeine, and ethylmorphine; however, 7,8-saturated congeners such as dihydromorphine and dihydrocodeine were poor substrates. The enzyme was inactivated by removal of 2-mercaptoethanol from the enzyme solution. The inactivated enzyme was rapidly recovered by the addition of 2-mercaptoethanol. Phenylarsine oxide and CdCl2 (dithiol modifiers) inhibited competitively toward cofactor binding and noncompetitively toward morphine binding. These results suggest that the enzyme possesses the essential thiol groups, probably vicinal dithiol, at or near the cofactor-binding site. Using the partially purified enzyme, 8-(2-hydroxyethylthio)dihydromorphinone was isolated as the product and identified by UV, mass, and NMR spectra. It was confirmed that morphinone proposed as the dehydrogenation product was nonenzymatically and covalently bound to 2-mercaptoethanol. Accordingly, the isolated morphinone-2-mercaptoethanol conjugate must be formed by two steps: enzymatic production of morphinone from morphine and then nonenzymatic binding of 2-mercaptoethanol to morphinone. PMID:2580834

  4. Optic nerve head and intraocular pressure in the guinea pig eye.

    PubMed

    Ostrin, Lisa A; Wildsoet, Christine F

    2016-05-01

    The guinea pig is becoming an increasingly popular model for studying human myopia, which carries an increased risk of glaucoma. As a step towards understanding this association, this study sought to characterize the normal, developmental intraocular pressure (IOP) profiles, as well as the anatomy of the optic nerve head (ONH) and adjacent sclera of young guinea pigs. IOP was tracked in pigmented guinea pigs up to 3 months of age. One guinea pig was imaged in vivo with OCT and one with a fundus camera. The eyes of pigmented and albino guinea pigs (ages 2 months) were enucleated and sections from the posterior segment, including the ONH and surrounding sclera, processed for histological analyses - either hematoxylin and eosin (H&E) staining of paraffin embedded, sectioned tissue (n = 1), or cryostat sectioned tissue, processed for immunohistochemistry (n = 3), using primary antibodies against collagen types I-V, elastin, fibronectin and glial fibrillary acidic protein (GFAP). Transmission and scanning electron microscopy (TEM, SEM) studies of ONHs were also undertaken (n = 2 & 5 respectively). Mean IOPs ranged from 17.33 to 22.7 mmHg, increasing slightly across the age range studied, and the IOPs of individual animals also exhibited diurnal variations, peaking in the early morning (mean of 25.8, mmHg, ∼9 am), and decreasing across the day. H&E-stained sections showed retinal ganglion cell axons organized into fascicles in the prelaminar and laminar region of the ONHs, with immunostained sections revealing collagen types I, III, IV and V, as well as elastin, GFAP and fibronectin in the ONHs. SEM revealed a well-defined lamina cribrosa (LC), with radially-oriented collagen beams. TEM revealed collagen fibrils surrounding non-myelinated nerve fiber bundles in the LC region, with myelination and decreased collagen posterior to the LC. The adjacent sclera comprised mainly crimped collagen fibers in a crisscross arrangement. Both the sclera and LC were

  5. Interaction of glutathione and ascorbic acid in guinea pig lungs exposed to nitrogen dioxide

    SciTech Connect

    Leung, H.-W.; Morrow, P.E.

    1981-01-01

    The interaction of two important water-soluble antioxidants, glutathione and ascorbic acid, was studied. The perfused guinea pig lung was found to contain about twice as much reduced glutathione as ascorbic acid. Nitrogen dioxide exposure decreased the levels of the two antioxidants both in vitro and in vivo. Ascorbic acid concentration was lowered to a greater extent than glutathione. The pulmonary ascorbic acid level was identical in both control and glutathione-deficient guinea pigs exposed to nitrogen dioxide, suggesting that there was little interaction between the two antioxidants in the lungs during oxidant stress.

  6. Effect of cinitapride in isolated ileum obtained from guinea-pigs treated with morphine.

    PubMed

    Colado, M I; Alfaro, M J; del Val, V L; Martín, M I

    1991-01-01

    1. Cinitapride enhanced the contractile response induced by electrical stimulation in the guinea-pig myenteric plexus-longitudinal muscle strip preparations. 2. The contractile force was significantly increased in strips pretreated with morphine "in vitro" and in tolerant strips. 3. However when tissues were obtained from tolerant guinea-pigs and morphine was not added to the organ bath (morphine-abstinence), the cinitapride effect was significantly decreased. 4. Although further work is required to explain the changes in the effect of cinitapride after acute morphine treatment and in morphine tolerant tissues, the changes observed suggest that some of the cinitapride effects could be linked with the peripheral opioid system. PMID:1662171

  7. Evidence for a non-opioid sigma binding site din the guinea-pig myenteric plexus

    SciTech Connect

    Roman, F.; Pascaud, X.; Vauche, D.; Junien, J.

    1988-01-01

    The presence of a binding site to (+)-(/sup 3/H)SKF 10,047 was demonstrated in a guinea-pig myenteric plexus (MYP) membrane preparation. Specific binding to this receptor was saturable, reversible, linear with protein concentration and consisted of two components, a high affinity site and a low affinity site. Morphine and naloxone 10/sup -4/M were unable to displace (+)-(/sup 3/H)SKF 10,047 binding. Haloperidol, imipramine, ethylketocyclazocine and propranolol were among the most potent compounds to inhibit this specific binding. These results suggest the presence of a non-opioid haloperidol sensitive sigma receptor in the MYP of the guinea-pig.

  8. Stimulation of anti-tumour immunity in guinea-pigs by methanol extraction residue of BCG.

    PubMed Central

    Wainberg, M. A.; Deutsch, V.; Weiss, D. W.

    1976-01-01

    The immunoprophylactic effects of the methanol extraction residue (MER) of BCG were investigated in Strain 2 guinea-pigs injected with cells of the transplantable, diethylnitrosamine-induced, Line 10 hepatocarcinoma. Pretreatment with MER at times ranging from 18 to 182 days prior to tumour implantation protected approximately 40% of guinea-pigs from progressive neoplastic disease. In addition, MER-treated animals developed specific cell-mediated anti-tumour immunity both more rapidly and at higher levels than did non-MER-treated tumour-bearing controls. It was not possible, however, to prognosticate from the results of such laboratory studies to the outcome of immunoprophylaxis. PMID:187207

  9. Digesta retention and fibre digestion in maras (Dolichotis patagonum) and guinea-pigs.

    PubMed

    Sakaguchi, E; Nippashi, K; Endoh, G

    1992-04-01

    1. Digestibilities of feed and turnover time (1/k), transit time (TT) and mean retention time (MRT: 1/k+TT) of fluid and particle markers were measured in maras (Dolichotis patagonum) and guinea-pigs (Cavia procellus) fed a diet containing 50% alfalfa. 2. The digestibility of fibre was similar in both animals, however, the digestibilities of crude protein (nitrogen x 6.25) and crude ash were lower in the mara than in the guinea-pig. 3. 1/k of the digesta markers were similar in both animals, suggesting that the two animals possess similar dilution and retention time of digesta in their caecum and proximal colon. PMID:1351463

  10. The vertebrobasilar arterial system in guinea pig as compared with dog and human.

    PubMed

    Majewska-Michalska, E

    1998-01-01

    The arterial system formed by branches of the vertebral and basilar arteries in guinea pig was compared to that of dog and human. The vertebrobasilar arterial system in particular species shows similarities and differences, considering its structure and arising branches. The differences are mainly due to the length of the basilar artery. In guinea pig the vertebrobasilar system distribute blood to the 2/3 of the brain. The same distribution is in dog. In human the carotid system predominates in the supply of the brain. PMID:9835170

  11. The effect of cardiac glycosides on the Na+ pump current-voltage relationship of isolated rat and guinea-pig heart cells.

    PubMed Central

    Hermans, A N; Glitsch, H G; Verdonck, F

    1994-01-01

    1. Whole-cell recording from isolated rat and guinea-pig ventricular myocytes revealed a change of the cardiac Na+ pump current (Ip)-voltage (V) relationship by cardiac glycosides, specific inhibitors of the Na(+)-K+ pump. 2. Dihydro-ouabain (DHO) diminished Ip in rat ventricular cells at 0 mV in a concentration-dependent manner. 3. The concentration-response curve of Ip inhibition caused by DHO was shifted to higher [DHO] at higher extracellular K+ concentrations ([K+]o) or at more negative membrane potentials. 4. In rat myocytes, DHO immediately flattened the normalized cardiac Ip-V curve and evoked or enhanced a region of negative slope. 5. Ouabain, at concentrations which caused a comparable inhibition of Ip, exerted DHO-like effects on the Ip-V relationship of rat ventricular myocytes. However, the effects developed more slowly. 6. A slowly developing alteration of the Ip-V curve was also observed upon application of DHO to guinea-pig ventricular cells. The range of [DHO] used was about 100-fold lower than that applied to rat ventricular cells, but was equally effective for Ip inhibition. 7. Increasing the K+ concentration of DHO-containing media affected the existing equilibrium of DHO binding to the cardiac Na(+)-K+ pump. A new equilibrium was reached within about 3 s in rat ventricular myocytes, but only within about 50 s in guinea-pig ventricular cells under the experimental conditions chosen. 8. It is concluded that the changes of the cardiac Ip-V curve induced by cardiac glycosides are mediated by voltage-dependent variations of the local [K+]o at the K+ binding sites of the Na(+)-K+ pump in an 'access channel'. The variations were estimated by means of the Boltzmann equation. The estimations agreed with those derived from the measured DHO binding to the Na(+)-K+ pump at various [K+]o. A new equilibrium of glycoside binding to the pump is established at the altered [K+]o. The time necessary to reach the new binding equilibrium varies with the

  12. Studies on vertical transmission of Trichinella spp. in experimentally infected ferrets (Mustela putorius furo), foxes (Vulpes vulpes), pigs, guinea pigs and mice.

    PubMed

    Webster, P; Kapel, C M O

    2005-06-30

    Vertical transmission of Trichinella spiralis was evaluated in ferrets (n=21), foxes (n=11), pigs (n=12), guinea pigs (n=16), and mice (n=41). The placental barrier to be crossed by migratory Trichinella larvae varies structurally in different animal species. Ferrets and foxes have an endotheliochorial placenta structure, guinea pigs and mice a haemochorial, and pigs an epitheliochorial placenta. The non-encapsulating Trichinella pseudospiralis larvae have an extended muscle migration prior to entering a muscle cell. To evaluate if T. pseudospiralis was more likely to be transmitted to offspring, an additional group of foxes (n=11) infected with T. pseudospiralis was included. Two different dose levels were used for ferrets, pigs, guinea pigs, and mice. In pigs and guinea pigs, infection was given at different times of the gestation period. Vertical transmission, measured as recovery of muscle larvae in the offspring, was demonstrated in both ferrets groups, in all four guinea pig groups, and in the high dose mouse group, but not in any fox or pig groups. PMID:15925725

  13. Propagation of pacemaker activity in the guinea-pig antrum

    PubMed Central

    Hennig, G W; Hirst, G D S; Park, K J; Smith, C B; Sanders, K M; Ward, S M; Smith, T K

    2004-01-01

    Cyclical periods of depolarization (slow waves) underlie peristaltic contractions involved in mixing and emptying of contents in the gastric antrum. Slow waves originate from a myenteric network of interstitial cells of Cajal (ICC-MY). In this study we have visualized the sequence and propagation of Ca2+ transients associated with pacemaker potentials in the ICC network and longitudinal (LM) and circular muscle (CM) layers of the isolated guinea-pig gastric antrum. Gastric antrum was dissected to reveal the ICC-MY network, loaded with Fluo-4 AM and activity was monitored at 37°C. Ca2+ waves propagated throughout the ICC-MY network at an average velocity of 3.24 ± 0.12 mm s−1 at a frequency of 4.87 ± 0.16 cycles min−1 (n = 4). The propagation of the Ca2+ wave often appeared ‘step-like’, with separate regions of the network being activated after variable delays. The direction of propagation was highly variable (Δ angle of propagation 44.3 ± 10.9 deg per cycle) and was not confined to the axes of the longitudinal or circular muscle. Ca2+ waves appeared to spread out radially from the site of initiation. The initiating Ca2+ wave in ICC-MY was correlated to secondary Ca2+ waves in intramuscular interstial cells of Cajal, ICC-IM, and smooth muscle cells, and the local distortion (contraction) in a field of view. TTX (1 μm) had little effect on slow wave or pacemaker potential activity, but 2-APB (50 μm) blocked all Ca2+ waves, indicating a pivotal role for intracellular Ca2+ stores. Nicardipine (2 μm) eliminated the Ca2+ transient generated by smooth muscle, but did not affect the fast upstroke associated with ICC-MY. These results indicate that slow waves follow a sequence of activation, beginning with the ICC-MY and ICC-IM network, followed later by a sustained Ca2+ transient in the muscle layers that is responsible for contraction. PMID:14754999

  14. Recognition of Modified Conditioning Sounds by Competitively Trained Guinea Pigs

    PubMed Central

    Ojima, Hisayuki; Horikawa, Junsei

    2016-01-01

    The guinea pig (GP) is an often-used species in hearing research. However, behavioral studies are rare, especially in the context of sound recognition, because of difficulties in training these animals. We examined sound recognition in a social competitive setting in order to examine whether this setting could be used as an easy model. Two starved GPs were placed in the same training arena and compelled to compete for food after hearing a conditioning sound (CS), which was a repeat of almost identical sound segments. Through a 2-week intensive training, animals were trained to demonstrate a set of distinct behaviors solely to the CS. Then, each of them was subjected to generalization tests for recognition of sounds that had been modified from the CS in spectral, fine temporal and tempo (i.e., intersegment interval, ISI) dimensions. Results showed that they discriminated between the CS and band-rejected test sounds but had no preference for a particular frequency range for the recognition. In contrast, sounds modified in the fine temporal domain were largely perceived to be in the same category as the CS, except for the test sound generated by fully reversing the CS in time. Animals also discriminated sounds played at different tempos. Test sounds with ISIs shorter than that of the multi-segment CS were discriminated from the CS, while test sounds with ISIs longer than that of the CS segments were not. For the shorter ISIs, most animals initiated apparently positive food-access behavior as they did in response to the CS, but discontinued it during the sound-on period probably because of later recognition of tempo. Interestingly, the population range and mean of the delay time before animals initiated the food-access behavior were very similar among different ISI test sounds. This study, for the first time, demonstrates a wide aspect of sound discrimination abilities of the GP and will provide a way to examine tempo perception mechanisms using this animal species

  15. NITROGEN DIOXIDE EXPOSURE AND LUNG ANTIOXIDANTS IN ASCORBIC ACID-DEFICIENT GUINEA PIGS

    EPA Science Inventory

    The authors have previously found that ascorbic acid (AA) deficiency in guinea pigs enhances the pulmonary toxicity of nitrogen dioxide (NO2). The present study showed that exposure to NO2 (4.8 ppm, 3 hr) significantly increased lung lavage fluid protein (a sensitive indicator of...

  16. PLACENTAL TRANSFER AND FETAL DEPOSITION OF HEXACHLOROBENZENE IN THE HAMSTER AND GUINEA PIG

    EPA Science Inventory

    Hexachlorobenzene (HCB) was administered at dose levels of 0, 1.0, 10.0, or 50.0 mg HCB/kg body wt by gavage to pregnant hamsters and guinea pigs for 6 days up to the time of liver development in the fetus. Samples of maternal fat, thymus, skin, liver, lung, brain, spleen, urinar...

  17. Endogenous histamine and promethazine-induced gastric ulcers in the guinea pig

    NASA Technical Reports Server (NTRS)

    Djahanguiri, B.; Hemmati, M.

    1978-01-01

    Experiments performed with an inhibitor of diaminoxydase, aminoguanidine and an inhibitor of histidine decarboxylase, NSD 1055, showed that the frequency of gastric ulcers induced by promethazine was increased with the first inhibitor and decreased with the second. It is suggested that ulcers induced by promethazine in guinea pigs might be due to histamino-liberator effect of the antihistaminio compound.

  18. ALTERED FUNCTION AND HISTOLOGY IN GUINEA PIGS AFTER INHALATION OF DIESEL EXHAUST

    EPA Science Inventory

    Health effects of inhaled diesel engine exhaust were evaluated in infant guinea pigs following 4 and 8 weeks of exposure. Animals were exposed to 1 part exhaust diluted by 13 parts clean air for 20 hr/day, 7 days/week. Lung function, electrocardiogram, growth rate, and histopatho...

  19. Pancreatic lesions induced in rabbits and guinea-pigs with pancreatic antigens.

    PubMed Central

    Wright, P H; Gingerich, R L; King, S; Lacy, P E

    1976-01-01

    Rabbits and guinea-pigs were immunized with various pancreatic antigens in Freund's adjuvant. Rabbits received unfractionated bovine insulin and the "A" component and "single peak" insulin separated from it by gel-filtration. All produced antibodies capable of reacting with porcine insulin but none were found to have pancreatic lesions when killed up to 6 weeks after initial injection. Guinea-pigs immunized with bovine "A" component developed pancreatic peri-ductulitis which appeared most frequently (10/20) in animals killed 30 days after a single injection and less frequently in animals killed after 60 (4/10) and 90(1/10) days. Similar lesions were found in only a small proportion of control animals (2/23) or of guinea-pigs immunized with single peak bovine insulin (3/22). Guinea-pigs immunized with homogenates of homologous and heterologous islets of Langerhans developed signs of peri-ductulitis in a high proportion of animals killed up to about 60 days after first injection (18/26). None of these animals exhibited clearly defined signs of diabetes mellitus and the incidence of induced lesions could not be correlated with levels of circulating insulin-binding antibodies. Images Fig. 2 PMID:821683

  20. Development and duration of BCG-induced allergy in the guinea-pig*

    PubMed Central

    Tolderlund, Knud; Bunch-Christensen, Kirsten; Waaler, Hans

    1960-01-01

    In assessing the biological activity of BCG vaccine by tuberculin testing of vaccinated guinea-pigs, it is necessary to take into account the rates of development and waning of allergy, and also the boosting effect on waning allergy caused by the tuberculin test itself. Using Danish liquid vaccine (in approximately standard dose), the authors have carried out two series of tests, involving more than six hundred guinea-pigs, to evaluate the significance of these factors. Post-vaccination tuberculin sensitivity was found to reach a maximum within 1-2 months. Three months after vaccination the BCG-induced allergy began to wane, and after 12 months it had dropped almost to the level observed in non-vaccinated guinea-pigs. The tuberculin test had a strong boosting effect, however, and even 12 months after vaccination the waning sensitivity could be considerably increased by a single injection of 10 TU of tuberculin. An analysis of the results showed that the waning of the level of allergy takes place gradually over several months. This is not an effect of aging, however, as the response to vaccination was found to be independent of the age of the animals. The indications of this study are that tuberculin testing of guinea-pigs used for the laboratory control of BCG vaccine is best performed about 6 weeks after vaccination. PMID:20604065

  1. Protection of guinea pigs against Leptospira interrogans serovar Lai by LipL21 DNA vaccine.

    PubMed

    He, Han Jiang; Wang, Wen Yu; Wu, Zhong Dao; Lv, Zhi Yue; Li, Jun; Tan, Li Zhi

    2008-10-01

    In this study, the full lipL21 gene fragment encoding outer membrane protein LipL21 was cloned from L. interrogans serovar Lai and inserted into eukaryotic expression vector pcDNA3.1(+). The guinea pigs were immunized with pcDNA3.1(+)-lipL21, pcDNA3.1(+) or PBS. Six weeks after the second immunization, the splenocytes were isolated to detect their proliferative ability by lymphocyte transformation experiments. In addition, microscopic agglutination test was used for quantitative detection of specific antibodies. The rest guinea pigs were challenged intraperitoneally with L. interogans sorevar Lai. Then, protective effect was evaluated on the basis of survival and histopathological lesions in the kidneys, lungs, and liver. The lipL21 gene was successfully expressed in COS-7 cells through recombinant pcDNA3.1(+)-lipL21. The titer of specific antibodies substantially increased, and the stimulation index of splenocytes increased significantly. Hence, the pcDNA3.1(+)-lipL21 could protect the immunized guinea pigs from homotypic Leptospira infection. Furthermore, no obvious pathologic changes were observed in the pcDNA3.1(+)-lipL21 immunized guinea pigs. The results showed that the protective effect with pathogenic strains of Leptospira was shared by LipL21 mediated through a plasmid vector. Consequently, these results indicated that the lipL21 DNA vaccine was a promising candidate for the prevention of leptospirosis. PMID:18954563

  2. Use of a Far-Infrared Active Warming Device in Guinea Pigs (Cavia porcellus)

    PubMed Central

    Zarndt, Bethany S; Buchta, Jessica N; Garver, Lindsey S; Davidson, Silas A; Rowton, Edgar D; Despain, Kenneth E

    2015-01-01

    Small mammals have difficulty maintaining body temperature under anesthesia. This hypothermia is a potential detriment not only to the health and comfort of the animal but also to the integrity of any treatment given or data gathered during the anesthetic period. Using an external warming device to assist with temperature regulation can mitigate these effects. In this study, we investigated the ability of an advanced warming device that uses far-infrared (FIR) heating and responds to real-time core temperature monitoring to maintain a normothermic core temperature in guinea pigs. Body temperatures were measured during 30 min of ketamine–xylazine general anesthesia with and without application of the heating device. The loss of core body heat from anesthetized guinea pigs under typical (unwarmed) conditions was significant, and this loss was almost completely mitigated by application of the FIR heating pad. The significant difference between the temperatures of the actively warmed guinea pigs as compared with the control group began as early as 14 min after anesthetic administration, leading to a 2.6 °C difference at 30 min. Loss of core body temperature was not correlated with animals’ body weight; however, weight influences the efficiency of FIR warming slightly. These study results show that the FIR heating device accurately controls core body temperature in guinea pigs, therefore potentially alleviating the effects of body heat loss on animal physiology. PMID:26632788

  3. COMPARATIVE GENOTOXIC RESPONSES TO ARSENITE IN GUINEA PIG, MOUSE, RAT AND HUMAN LYMPHOCYTES

    EPA Science Inventory

    Comparative genotoxic responses to arsenite in guinea pig, mouse, rat and human
    lymphocytes.

    Inorganic arsenic is a known human carcinogen causing skin, lung, and bladder cancer following chronic exposures. Yet, long-term laboratory animal carcinogenicity studies have ...

  4. Contractile responses in bladder body, bladder neck and prostate from rat, guinea pig and cat.

    PubMed

    Cohen, M L; Drey, K

    1989-03-01

    Lower urinary tract smooth muscle displays marked heterogeneity in pharmacologic responsiveness to contractile agents. The present study details differences among species with regard to muscarinic, adrenergic, histaminergic and serotonergic agonists in the bladder body, bladder neck and prostate from guinea pig, rat and cat. Under in vitro conditions, all smooth muscle preparations contracted to potassium chloride. The muscarinic agonist, carbamylcholine, produced maximal contraction, whereas alpha receptor agonists exerted only minimal, if any, effect in bladder body preparations from all three species. In contrast, alpha receptor-mediated responses predominated relative to muscarinic responses in bladder neck preparations from all three species. Prostatic contractility was examined in tissue from guinea pig and rat and contraction occurred to both alpha and muscarinic receptor agonists. Contractile response to norepinephrine in bladder neck and prostate was potentiated by neuronal uptake inhibition but not by beta receptor blockade. Serotonin and histamine exhibited more diverse effects among species and tissues. In general, histamine contracted all three tissues from guinea pig with minimal contraction occurring in tissues from rat or cat. On the other hand, serotonin markedly contracted the cat bladder body and rat prostate, but exerted no effect on tissues from the guinea pig. These data reinforce and detail the heterogeneity of pharmacologic contractile responses in lower urinary tract smooth muscle. Furthermore, the studies document the relative similarity among species in cholinergic and adrenergic responsiveness and the dissimilarity among species in serotonergic and histaminergic responsiveness of lower urinary tract smooth muscle. PMID:2539454

  5. Papular Dermatitis Induced in Guinea Pig by Biting Midge Culicoides Sonorensis (Diptera: Ceratopogonidaie)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Histological, ultrastructural, and virological examinations were performed on abdominal skin from guinea pigs after a blood meal by colony-bred biting midges, Culicoides sonorensis. Small, superficial, cutaneous, crateriform ulcers with necrosis of superficial dermis developed at feeding sites and h...

  6. The influence of starvation upon hepatic drug metabolism in rats, mice, and guinea pigs.

    NASA Technical Reports Server (NTRS)

    Furner, R. L.; Feller, D. D.

    1971-01-01

    Male rats, mice, and guinea pigs were starved for 1, 2, or 3 days, and the metabolism of ethylmorphine, p-nitroanisole, and aniline was studied. Results suggest that the oxidative enzyme systems studied are not interdependent, and the pathways studied appear to be species dependent.

  7. Use of a Far-Infrared Active Warming Device in Guinea Pigs (Cavia porcellus).

    PubMed

    Zarndt, Bethany S; Buchta, Jessica N; Garver, Lindsey S; Davidson, Silas A; Rowton, Edgar D; Despain, Kenneth E

    2015-11-01

    Small mammals have difficulty maintaining body temperature under anesthesia. This hypothermia is a potential detriment not only to the health and comfort of the animal but also to the integrity of any treatment given or data gathered during the anesthetic period. Using an external warming device to assist with temperature regulation can mitigate these effects. In this study, we investigated the ability of an advanced warming device that uses far-infrared (FIR) heating and responds to real-time core temperature monitoring to maintain a normothermic core temperature in guinea pigs. Body temperatures were measured during 30 min of ketamine-xylazine general anesthesia with and without application of the heating device. The loss of core body heat from anesthetized guinea pigs under typical (unwarmed) conditions was significant, and this loss was almost completely mitigated by application of the FIR heating pad. The significant difference between the temperatures of the actively warmed guinea pigs as compared with the control group began as early as 14 min after anesthetic administration, leading to a 2.6 °C difference at 30 min. Loss of core body temperature was not correlated with animals' body weight; however, weight influences the efficiency of FIR warming slightly. These study results show that the FIR heating device accurately controls core body temperature in guinea pigs, therefore potentially alleviating the effects of body heat loss on animal physiology. PMID:26632788

  8. Effect of ozone exposure on antigen-induced airway hyperresponsiveness in guinea pigs

    SciTech Connect

    Vargas, M.H.; Segura, P.; Campos, M.G.; Hong, E.; Montano, L.M.

    1994-12-31

    Airway hyperresponsiveness can be induced by several stimuli including antigen and ozone, both of which may be present in the air of polluted cities. Though the effect of ozone on the bronchoconstrictor response to antigen has been well described, the combined effect of these stimuli on airway hyperresponsiveness has not yet been studied. Sensitized guinea pigs with or without ozone exposure for 1 h at 3 ppm, 18 h prior to study, were challenged with a dose-response curve to histamine (0.01-1.8 {mu}g/kg, iv), and then by a second histamine dose-response curve 1 h later. Airway responses were measured as the increase in pulmonary insufflation pressure. In sensitized guinea pigs, the histamine ED50 significantly decreased after antigen challenge, demonstrating the development of airway hyperresponsiveness. Sensitized guinea pigs exposed to ozone showed airway hyperresponsiveness to histamine when compared with nonexposed animals, and such hyperresponsiveness was further enhanced after antigen challenge. We conclude that in this guinea pig model of acute allergic bronchoconstriction both antigen challenge and ozone induce airway hyperresponsiveness, while ozone exposure does not modify the development of antigen-induced hyperresponsiveness. 25 refs., 1 fig., 1 tab.

  9. Effects of ozone and sulfuric acid aerosol on gas trapping in the guinea pig lung

    SciTech Connect

    Silbaugh, S.A.; Mauderly, J.L.

    1986-01-01

    Four groups of 20 guinea pigs were sequentially exposed by inhalation to either air followed by sulfuric acid aerosol, ozone followed by sulfuric acid aerosol, ozone followed by air, or air followed by air to determine whether ozone preexposure sensitizes guinea pigs to the airway constrictive effects of sulfuric acid aerosol. All first exposures to ozone or air were 2 h in duration; all second exposures to sulfuric acid or air were for 1 h. All ozone and sulfuric acid exposures were 0.8 ppm and 12 mg/m3, respectively. Animals were observed for respiratory distress during exposure, and excised lungs were quantitated for trapped gas and wet/dry ratios. None of the guinea pigs developed dyspnea, and wet/dry ratios were not altered. Ozone significantly (p less than 0.05) increased trapped gas volumes, which were 44% (ozone-acid) to 68% (ozone-air) greater than in the air-air group. Trapped gas volume was 23% greater in the ozone-acid group than in the air-acid group, but the difference was not statistically significant (p less than 0.20). Thus, ozone increased gas trapping but did not significantly sensitize guinea pigs to the bronchoconstrictive action of sulfuric acid.

  10. Specific activities of antioxidative enzymes in the cochlea of guinea pigs at different stages of development.

    PubMed

    Zelck, U; Nowak, R; Karnstedt, U; Koitschev, A; Käcker, N

    1993-01-01

    Significant activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were found in the cochleas of guinea pigs of different ages. The specific activities of SOD and GSH-Px (expressed as units/mg protein) increased significantly from fetal animals to animals 2 days old and then to 6-month-old animals. PMID:8369116

  11. Contractile properties of synthetic cationic polypeptides in guinea-pig isolated trachea.

    PubMed Central

    Spina, D.; Goldie, R. G.

    1994-01-01

    1. The synthetic polypeptides, poly-L-arginine, poly-L-lysine and poly-D-lysine contract guinea-pig isolated trachea in a concentration-dependent, epithelium-independent manner. Indomethacin augmented the contractile response to poly-L-arginine. 2. The contractile response to poly-L-arginine was not significantly inhibited by nicardipine, a selective L-type calcium channel blocker or by the histamine H1-receptor antagonist, mepyramine nor significantly augmented by the neutral endopeptidase inhibitor, phosphoramidon. 3. The contractile response to poly-L-arginine was inhibited in a concentration-dependent manner by prior incubation of guinea-pig tracheal rings with a number of anionic polypeptides including, low molecular weight heparin, poly-L-aspartic acid and bovine serum albumin. 4. In vitro capsaicin-induced desensitization failed to attenuate the contractile response to poly-L-arginine, suggesting little, if any role for sensory neuropeptides in the functional response in the guinea-pig. 5. Synthetic polypeptides induce an epithelium-independent, charge-dependent contraction of guinea-pig isolated trachea. PMID:8012709

  12. Protein A suppresses immune responses during Staphylococcus aureus bloodstream infection in guinea pigs

    DOE PAGESBeta

    Kim, Hwan Keun; Falugi, Fabiana; Thomer, Lena; Missiakas, Dominique M.; Schneewind, Olaf

    2015-01-06

    Staphylococcus aureus infection is not associated with the development of protective immunity, and disease relapses occur frequently. We hypothesize that protein A, a factor that binds immunoglobulin Fcγ and cross-links VH3 clan B cell receptors (IgM), is the staphylococcal determinant for host immune suppression. To test this, vertebrate IgM was examined for protein A cross-linking. High VH3 binding activity occurred with human and guinea immunoglobulin, whereas mouse and rabbit immunoglobulins displayed little and no binding, respectively. Establishing a guinea pig model of S. aureus bloodstream infection, we show that protein A functions as a virulence determinant and suppresses host Bmore » cell responses. Immunization with SpAKKAA, which cannot bind immunoglobulin, elicits neutralizing antibodies that enable guinea pigs to develop protective immunity.« less

  13. Computed tomography analysis of guinea pig bone: architecture, bone thickness and dimensions throughout development

    PubMed Central

    Witkowska, Agata; Alibhai, Aziza; Hughes, Chloe; Price, Jennifer; Klisch, Karl; Sturrock, Craig J.

    2014-01-01

    The domestic guinea pig, Cavia aperea f. porcellus, belongs to the Caviidae family of rodents. It is an important species as a pet, a source of food and in medical research. Adult weight is achieved at 8–12 months and life expectancy is ∼5–6 years. Our aim was to map bone local thickness, structure and dimensions across developmental stages in the normal animal. Guinea pigs (n = 23) that had died of natural causes were collected and the bones manually extracted and cleaned. Institutional ethical permission was given under the UK Home Office guidelines and the Veterinary Surgeons Act. X-ray Micro Computed Tomography (microCT) was undertaken on the left and right scapula, humerus and femur from each animal to ascertain bone local thickness. Images were also used to undertake manual and automated bone measurements, volumes and surface areas, identify and describe nutrient, supratrochlear and supracondylar foramina. Statistical analysis between groups was carried out using ANOVA with post-hoc testing. Our data mapped a number of dimensions, and mean and maximum bone thickness of the scapula, humerus and femur in guinea pigs aged 0–1 month, 1–3 months, 3–6 months, 6 months–1 year and 1–4 years. Bone dimensions, growth rates and local bone thicknesses differed between ages and between the scapula, humerus and femur. The microCT and imaging software technology showed very distinct differences between the relative local bone thickness across the structure of the bones. Only one bone showed a singular nutrient foramen, every other bone had between 2 and 5, and every nutrient canal ran in an oblique direction. In contrast to other species, a supratrochlear foramen was observed in every humerus whereas the supracondylar foramen was always absent. Our data showed the bone local thickness, bone structure and measurements of guinea pig bones from birth to 4 years old. Importantly it showed that bone development continued after 1 year, the point at which most

  14. Sp8 expression in putative neural progenitor cells in guinea pig and human cerebrum.

    PubMed

    Zhang, Xue-Mei; Cai, Yan; Wang, Fang; Wu, Jun; Mo, Lin; Zhang, Feng; Patrylo, Peter R; Pan, Aihua; Ma, Chao; Fu, Jin; Yan, Xiao-Xin

    2016-09-01

    Neural stem/progenitor cells have been characterized at neurogenic sites in adult mammalian brain with various molecular markers. Here it has been demonstrated that Sp8, a transcription factor typically expressed among mature GABAergic interneurons, also labels putative neural precursors in adult guinea pig and human cerebrum. In guinea pigs, Sp8 immunoreactive (Sp8+) cells were localized largely in the superficial layers of the cortex including layer I, as well as the subventricular zone (SVZ) and subgranular zone (SGZ). Sp8+ cells at the SGZ showed little colocalization with mature and immature neuronal markers, but co-expressed neural stem cell markers including Sox2. Some layer I Sp8+ cells also co-expressed Sox2. The amount of Sp8+ cells in the dentate gyrus was maintained 2 weeks after X-ray irradiation, while that of doublecortin (DCX+) cells was greatly reduced. Mild ischemic insult caused a transient increase of Sp8+ cells in the SGZ and layer I, with the subgranular Sp8+ cells exhibited an increased colabeling for the mitotic marker Ki67 and pulse-chased bromodeoxyuridine (BrdU). Sp8+ cells in the dentate gyrus showed an age-related decline in guinea pigs, in parallel with the loss of DCX+ cells in the same region. In adult humans, Sp8+ cells exhibited comparable morphological features as seen in guinea pigs, with those at the SGZ and some in cortical layer I co-expressed Sox2. Together, these results suggested that Sp8 may label putative neural progenitors in guinea pig and human cerebrum, with the labeled cells in the SGZ appeared largely not mitotically active under normal conditions. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 939-955, 2016. PMID:26585436

  15. Pathology and Pathophysiology of Inhalational Anthrax in a Guinea Pig Model

    PubMed Central

    Savransky, Vladimir; Sanford, Daniel C.; Syar, Emily; Austin, Jamie L.; Tordoff, Kevin P.; Anderson, Michael S.; Stark, Gregory V.; Barnewall, Roy E.; Briscoe, Crystal M.; Lemiale-Biérinx, Laurence; Park, Sukjoon; Ionin, Boris

    2013-01-01

    Nonhuman primates (NHPs) and rabbits are the animal models most commonly used to evaluate the efficacy of medical countermeasures against anthrax in support of licensure under the FDA's “Animal Rule.” However, a need for an alternative animal model may arise in certain cases. The development of such an alternative model requires a thorough understanding of the course and manifestation of experimental anthrax disease induced under controlled conditions in the proposed animal species. The guinea pig, which has been used extensively for anthrax pathogenesis studies and anthrax vaccine potency testing, is a good candidate for such an alternative model. This study was aimed at determining the median lethal dose (LD50) of the Bacillus anthracis Ames strain in guinea pigs and investigating the natural history, pathophysiology, and pathology of inhalational anthrax in this animal model following nose-only aerosol exposure. The inhaled LD50 of aerosolized Ames strain spores in guinea pigs was determined to be 5.0 × 104 spores. Aerosol challenge of guinea pigs resulted in inhalational anthrax with death occurring between 46 and 71 h postchallenge. The first clinical signs appeared as early as 36 h postchallenge. Cardiovascular function declined starting at 20 h postexposure. Hematogenous dissemination of bacteria was observed microscopically in multiple organs and tissues as early as 24 h postchallenge. Other histopathologic findings typical of disseminated anthrax included suppurative (heterophilic) inflammation, edema, fibrin, necrosis, and/or hemorrhage in the spleen, lungs, and regional lymph nodes and lymphocyte depletion and/or lymphocytolysis in the spleen and lymph nodes. This study demonstrated that the course of inhalational anthrax disease and the resulting pathology in guinea pigs are similar to those seen in rabbits and NHPs, as well as in humans. PMID:23357384

  16. Structural and Kinetic Characterization of Guinea Pig l-Asparaginase Type III

    PubMed Central

    2015-01-01

    We investigated whether an uncharacterized protein from guinea pig could be the enzyme behind Kidd’s serendipitous discovery, made over 60 years ago, that guinea pig serum has cell killing ability. It has been long known that an enzyme with l-asparaginase activity is responsible for cell killing, although astonishingly, its identity remains unclear. Bacterial asparaginases with similar cell killing properties have since become a mainstay therapy of certain cancers such as acute lymphoblastic leukemia. By hydrolyzing asparagine to aspartate and ammonia, these drugs deplete the asparagine present in the blood, killing cancer cells that rely on extracellular asparagine uptake for survival. However, bacterial asparaginases can elicit an adverse immune response. We propose that replacement of bacterial enzymes with the guinea pig asparaginase responsible for serum activity, by its virtue of being more closely related to human enzymes, will be less immunogenic. To this goal, we investigated whether an uncharacterized protein from guinea pig with putative asparaginase activity, which we call gpASNase3, could be that enzyme. We examined its self-activation process (gpASNase3 requires autocleavage to become active), kinetically characterized it for asparaginase and β-aspartyl dipeptidase activity, and elucidated its crystal structure in both the uncleaved and cleaved states. This work reveals that gpASNase3 is not the enzyme responsible for the antitumor effects of guinea pig serum. It exhibits a low affinity for asparagine as measured by a high Michaelis constant, KM, in the millimolar range, in contrast to the low KM (micromolar range) required for asparaginase to be effective as an anticancer agent. PMID:24669941

  17. Effects of 900 MHz electromagnetic field emitted by cellular phones on electrocardiograms of guinea pigs.

    PubMed

    Meral, I; Tekintangac, Y; Demir, H

    2014-02-01

    This study was carried out to determine the effects of electromagnetic field (EMF) emitted by cellular phones (CPs) on electrocardiograms (ECGs) of guinea pigs. A total of 30 healthy guinea pigs weighing 500-800 g were used. After 1 week of adaptation period, animals were randomly divided into two groups: control group (n = 10) and EMF-exposed group (n = 20). Control guinea pigs were housed in a separate room without exposing them to EMFs of CPs. Animals in second group were exposed to 890-915 MHz EMF (217 Hz of pulse rate, 2 W of maximum peak power and 0.95 wt kg(-1) of specific absorption rate) for 12 h day(-1) (11 h 45 min stand-by and 15 min speaking mode) for 30 days. ECGs of guinea pigs in both the groups were recorded by a direct writing electrocardiograph at the beginning and 10th, 20th and 30th days of the experiment. All ECGs were standardized at 1 mV = 10 mm and with a chart speed of 50 mm sec(-1). Leads I, II, III, lead augmented vector right (aVR), lead augmented vector left (aVL) and lead augmented vector foot (aVF) were recorded. The durations and amplitudes of waves on the trace were measured in lead II. The data were expressed as mean with SEM. It was found that 12 h day(-1) EMF exposure for 30 days did not have any significant effects on ECG findings of guinea pigs. However, this issue needed to be further investigated in a variety of perspectives, such as longer duration of exposure to be able to elucidate the effects of mobile phone-induced EMFs on cardiovascular functions. PMID:24220873

  18. Pulmonary effects of inhaled zinc oxide in human subjects, guinea pigs, rats, and rabbits

    SciTech Connect

    Gordon, T.; Chen, L.C.; Fine, J.M.; Schlesinger, R.B.; Su, W.Y.; Kimmel, T.A.; Amdur, M.O. )

    1992-08-01

    Occupational exposure to freshly formed zinc oxide (ZnO) particles (less than 1.0 micron aerodynamic diameter) produces a well-characterized response known as metal fume fever. An 8-hr threshold limit value (TLV) of 5 mg/m3 has been established to prevent adverse health effects because of exposure to ZnO fumes. Because animal toxicity studies have demonstrated pulmonary effects near the current TLV, the present study examined the time course and dose-response of the pulmonary injury produced by inhaled ZnO in guinea pigs, rats, rabbits, and human volunteers. The test animals were exposed to 0, 2.5, or 5.0 mg/m3 ZnO for up to 3 hr and their lungs lavaged. Both the lavage fluid and recovered cells were examined for evidence of inflammation or altered cell function. The lavage fluid from guinea pigs and rats exposed to 5 mg/m3 had significant increases in total cells, lactate dehydrogenase, beta-glucuronidase, and protein content. These changes were greatest 24 hr after exposure. Guinea pig alveolar macrophage function was depressed as evidenced by in vitro phagocytosis of opsonized latex beads. Significant changes in lavage fluid parameters were also observed in guinea pigs and rats exposed to 2.5 mg/m3 ZnO. In contrast, rabbits showed no increase in biochemical or cellular parameters following a 2-hr exposure to 5 mg/m3 ZnO. Differences in total lung burden of ZnO, as determined in additional animals by atomic absorption spectroscopy, appeared to account for the observed differences in species responses. Although the lungs of guinea pigs and rats retained approximately 20% and 12% of the inhaled dose, respectively, rabbits retained only 5%.

  19. In vivo formation of nitrosocarbamates in the stomach of rats and guinea pigs

    SciTech Connect

    Rickard, R.W.; Dorough, H.W.

    1984-01-01

    The N-nitrosocarbamates are potent mutagens and carcinogens and have been synthesized under acid conditions that prevail in the human stomach. However, it has never been documented that nitrosocarbamates are actually formed in vivo in the stomach of any mammalian species. Using /sup 14/C-labeled carbaryl and carbofuran, attempts were made to isolate the nitroso derivatives from the stomach contents of rats and guinea pigs treated orally with the carbamate and sodium nitrite. Only trace quantities of nitrocarbamate were recovered from the rat stomach, whereas 0.5 to 2.0% of the carbamate doses were isolated as the nitroso derivative from the contents of the guinea pig stomach. The rather low apparent yields resulted in part from the instability of the nitrosocarbamates and from absorption of the carbamate and/or nitrosocarbamate from the stomach. Higher rates of synthesis were indicated by incubating the carbamates with sodium nitrite in the presence of the stomach contents at 37/sup 0/C for 15 min. About 30% nitrosation occurred with the guinea pig and about 0.5% with the rat. The difference was attributed to the pH of the gastric contents. For the rat, the pH ranged from 3 to 5; gastric contents of the guinea pig had a pH between 1 and 2. Since the pH of the human stomach is also in the pH 1-2 range, it is likely that nitrosation of carbamates in humans would be very similar to that in the guinea pig. 21 references, 3 figures, 3 tables.

  20. Metabolism and disposition of 2,3,7,8-tetrachlorodibenzo-p-dioxin in guinea pigs

    SciTech Connect

    Olson, J.R.

    1986-09-15

    Marked interspecies variability exists in the acute toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), with the guinea pig being the mammalian species most sensitive to the acute toxicity of TCDD. The metabolism and disposition of TCDD was investigated in guinea pigs for 45 days following a single exposure to purified (/sup 3/H)TCDD (0.56 microgram/kg, ip). Guinea pigs included in the toxicokinetic study gained body weight, maintained a normal relative body composition, and exhibited no gross signs of toxicity during the 45-day study. Approximately 36% of the dose of TCDD-derived /sup 3/H remained in the adipose tissue at 45 days following exposure to (/sup 3/H)TCDD, while the liver, pelt, and skeletal muscle and carcass each contained about 7% of the administered dose. Although most of the TCDD-derived radioactivity in liver, kidney, perirenal adipose tissue, and skeletal muscle represented unchanged TCDD, from 4 to 28% of the /sup 3/H was associated with metabolites of TCDD. This unexpected finding suggests that TCDD metabolites are not efficiently excreted from guinea pigs. The urinary and fecal excretion of TCDD-derived radioactivity followed apparent first-order kinetics, with an elimination half-life of 93.7 +/- 15.5 days (mean +/- SD). HPLC analysis of urine and bile from (/sup 3/H)TCDD-treated guinea pigs showed that all of the radioactivity represented metabolites of TCDD, indicating that these routes of elimination are dependent on prior metabolism of TCDD. However, 70 to 90% of the radioactivity in fecal samples was found to represent unmetabolized TCDD throughout the 45-day excretion study. The presence of TCDD in feces and its absence in bile suggest that the fecal excretion of unchanged TCDD resulted from the direct intestinal elimination of the lipophilic toxin.

  1. Characterization and distribution of putative 5-ht7 receptors in guinea-pig brain.

    PubMed Central

    To, Z. P.; Bonhaus, D. W.; Eglen, R. M.; Jakeman, L. B.

    1995-01-01

    1. In the presence of (-)-cyanopindolol (1.0 microM) and sumatriptan (1.0 microM), 0.5 nM [3H]-carboxamidotrytamine ([3H]-5-CT) labelled a single population of receptors in guinea-pig cerebral cortex membranes. 2. 5-HT-displaceable binding was rapid, saturable and reversible. A high affinity binding site was characterized both by equilibrium saturation (Kd = 0.76 +/- 0.28 nM; Bmax = 68.1 +/- 26.7 fmol mg-1 protein) and kinetic (Kd = 0.18 +/- 0.05 nM) analysis. The pharmacological profile of this site was similar to the profile obtained in transfected CHO-K1 cells expressing guinea-pig 5-ht7 receptors. 3. Autoradiographic analysis revealed a discrete localization of binding sites in guinea-pig brain, with the highest density of sites in the medial thalamic nuclei and related limbic and cortical regions. Moderate levels of binding were detected in sensory relay nuclei, substantia nigra, hypothalamus, central grey and dorsal raphe nuclei. This distribution corresponded to that observed using in situ hybridization with [35S]-UTP labelled riboprobes complementary to mRNA encoding the guinea-pig 5-ht7 receptor. 4. In conclusion, under appropriate conditions, [3H]-5-CT labelled a single population of saturable binding sites that corresponded to an endogenous 5-ht7 receptor in guinea-pig brain. The distribution of 5-ht7 receptors in thalamocortical and limbic brain regions suggests a role for these receptors in sensory and affective behaviours. Images Figure 5 Figure 6 PMID:7647964

  2. Semicarbazide-sensitive amine oxidase activity of guinea pig dorsal skin.

    PubMed

    Buffoni, F; Cambi, S; Banchelli, G; Ignesti, G; Pirisino, R; Raimondi, L

    1994-01-01

    A semicarbazide-sensitive amine oxidase activity with a high affinity for benzylamine (Bz.SSAO) (E.C. 1.4.3.6) is present in guinea pig dorsal skin. This enzymic activity oxidized benzylamine, histamine, 1,4-methylhistamine and acetylputrescine and was inhibited by semicarbazide and by B24 (3,5-diethoxy-4-aminomethylpyridine), a selective inhibitor of Bz.SSAO enzymes. It cross reacted with the antibodies raised against pure pig plasma benzylamine oxidase. Immunohistochemistry showed that it was localized in fibroblasts. Bz.SSAO activity of guinea pig dorsal skin increased during the process of skin healing. A treatment of the wounds with 3 micrograms of b-FGF significantly accelerated the process of skin healing and the increase of Bz.SSAO activity. PMID:7931260

  3. The pathogenesis of leptospirosis I. Hemorrhages in experimental leptospirosis in guinea pigs.

    PubMed

    Higgins, R; Cousineau, G

    1977-04-01

    In experimental infections of guinea pigs with a virulent strain of Leptospira icterohaemorrhagiae widespread hemorrhages were observed. Thrombocytopenia, prolongation of prothrombin, thrombin, partial thromboplastin and coagulation times, decrease of plasma fibrinogen, factor V, factor VIII and the presence of fibrinogen degradation products were demonstrated. Treatment of infected guinea pigs with heparin prolonged life for two to three days. The histological observations revealed that the main lesion is a severe injury of the vasculature, mainly arteries, arterioles and capillaries. Most of the endothelial cells are affected or destroyed and the muscular fibers of arteries and arterioles are injured. With Martius-Scarlet-Blue, Weigert or Picro-Mallory stains it was demonstrated that the organization seen in the vessels is not all made of fibrin. The conclusion reached was that the hemorrhages observed in experimental leptospirosis in guines pigs are due to disseminated intravascular coagulation. PMID:861835

  4. Intracellular Potassium Activity in Guinea Pig Papillary Muscle during Prolonged Hypoxia

    PubMed Central

    Guarnieri, Thomas; Strauss, Harold C.

    1982-01-01

    During prolonged hypoxia, intracellular potassium concentration, [K]i has been reported to fall by 70% with a concomitant decrease in the calculated potassium equilibrium potential, EK. Nevertheless, resting membrane potential, Vm, declined only slightly. Because Vm depolarized very little in relation to the calculated EK, it was hypothesized that electrogenic Na-K pumping contributed up to 40 mV to Vm during prolonged hypoxia. To further test this hypothesis we studied what changes prolonged hypoxia makes in the thermodynamically active fraction of cellular potassium, intracellular potassium activity, αKi, and how change in αKi affects the relationship between Vm, EK and, by inference, the Na-K pump. Using double-barrel K-selective electrodes, Vm and αKi were measured in quiescent guinea pig right ventricular papillary muscles superfused for 8 h with hypoxic Tyrode's solution. Over the 8-h period both Vm and αKi decreased. However, the decline in Vm was paralleled by a decrease in the EK calculated from αKi. At no time was there hyperpolarization of Vm beyond EK. After 8 h the Na-K pump was inhibited by exposing the muscles to 0.1 mM ouabain. The onset of an increase in extracellular potassium activity, measured with a double-barrel electrode, was used to mark the amount of depolarization of Vm due solely to pump inhibition. After hypoxia, Vm depolarized 8.4±4.4 mV before extracellular potassium activity (αKe) increased. Thus, the decrease in αKi during hypoxia is much less than that reported for [K]i. The parallel decline in Vm and EK and the small depolarization of Vm with ouabain suggest that after prolonged hypoxia the Na-K pump continues to contribute to Vm, but the amount of this contribution is substantially less than previously reported. PMID:6276442

  5. Test of the usefulness of a paradigm to identify potential cardiovascular liabilities of four test articles with varying pharmacological properties in anesthetized guinea pigs.

    PubMed

    Kijtawornrat, Anusak; Ueyama, Yukie; del Rio, Carlos; Sawangkoon, Suwanakiet; Buranakarl, Chollada; Chaiyabutr, Narongsak; Hamlin, Robert L

    2014-02-01

    The evaluation of proarrhythmic and hemodynamic liabilities for new compounds remains a major concern of preclinical safety assessment paradigms. Contrastingly, albeit functional liabilities can also translate to clinical morbidity and mortality, lesser preclinical efforts are focused on the evaluation of drug-induced changes in inotrope and lusitrope, particularly in the setting of concomitant hemodynamic/arrhythmic liabilities. This study aimed to establish the feasibility of an anesthetized guinea pig preparation to assess functional liabilities in the setting of simultaneous drug-induced electrocardiographic/hemodynamic changes, by evaluating the effects of various compounds with known cardiovascular properties on direct and indirect indices of left ventricular function. In short, twenty nine male guinea pigs were instrumented to measure electrocardiograms, systemic arterial pressure, and left ventricular pressure-volume relationships. After baseline measurement, all animals were given intravenous infusions of vehicle and two escalating concentrations of either chromanol 293B (n = 8), milrinone (n = 6), metoprolol (n = 7), or nicorandil (n = 8) for 10 minutes each. In all cases, these compounds produced the expected changes. The slope of preload-recruitable stroke work (PRSW), a pressure-volume derived load independent index, was the most sensitive marker of drug-induced changes in inotropy. Among the indirect functional indices studied, only the "contractility index" (dP/dtmax normalized by the pressure at its occurrence) and the static myocardial compliance (ratio of end diastolic volume and pressure) appeared to be adequate predictors of drug-induced changes in inotropy/lusitropy. Overall, the data confirms that both electrophysiological and mechanical liabilities can be accurately assessed in an anesthetized guinea pig preparation. PMID:24189130

  6. Comparison of guinea-pig, bovine and rat alpha 1-adrenoceptor subtypes.

    PubMed Central

    Büscher, R.; Heeks, C.; Taguchi, K.; Michel, M. C.

    1996-01-01

    1. To elucidate a possible role of species differences in the classification of alpha 1-adrenoceptor subtypes, we have characterized the alpha 1-adrenoceptors in guinea-pig spleen, kidney and cerebral cortex and in bovine cerebral cortex using concentration-dependent alkylation by chloroethylclonidine and competitive binding with 5-methlurapidil, methoxamine, (+)-niguldipine, noradrenaline, oxymetazoline, phentolamine, SDZ NVI-085, tamsulosin and (+)-tamsulosin. Rat liver alpha 1B-adrenoceptors were studied for comparison. Chloroethylclonidine-sensitivity and (+)-niguldipine affinity were also compared at cloned rat and bovine alpha 1a-adrenoceptors. 2. Chloroethylclonidine concentration-dependently inactivated alpha 1-adrenoceptors in all five tissues. While chloroethylclonidine inactivated almost all alpha 1-adrenoceptors in rat liver and guinea-pig kidney and brain, 20-30% of alpha 1-adrenoceptors in guinea-pig spleen and bovine brain were resistant to alkylation by 10 microM chloroethylclonidine. With regard to concentration-dependency guinea-pig kidney and brain were approximately 10 fold less sensitive than guinea-pig spleen or rat liver. 3. In rat liver, all drugs tested competed for [3H]-prazosin binding with steep and monophasic curves. Drug affinities were relatively low and resembled most closely those of cloned rat alpha 1b-adrenoceptors. 4. In guinea-pig spleen, all drugs tested competed for [3H]-prazosin binding with steep and monophasic curves. Drug affinities were relatively low and resembled most closely those of cloned rat alpha 1b-adrenoceptors. 5. In guinea-pig kidney most drugs tested competed for [3H]-prazosin binding with steep and monophasic curves and had relatively low drug affinities close to those of cloned rat alpha 1b- and alpha 1d-adrenoceptors. However, noradrenaline and tamsulosin had consistently biphasic competition curves recognizing 36-39% high and 61-64% low affinity sites. 6. In guinea-pig cerebral cortex, all drugs tested

  7. Studies on dioctyl sodium sulfosuccinate toxicity: clinical, gross and microscopic pathology in the horse and guinea pig.

    PubMed Central

    Moffatt, R E; Kramer, L L; Lerner, D; Jones, R

    1975-01-01

    Concentrations of dioctyl sodium sulfosuccinate (DSS) ranging from three to five times the recommended dosage produced severe diarrhea, rapid dehydration and death in seven horses and 66 guinea pigs when administered experimentally per os. Clinicopathological findings indicated hemoconcentration in both horses and guinea pigs. There was a leucocytosis in the guinea pigs given the highest dosages. In all cases the principal finding at necropsy was extreme fluid distention of the intestinal tract. There was histopathological evidence of epithelial denudation and vascular stasis. The LD50 in the guinea pig was approximately 0.65 g DSS/kg body weight. Images Fig. 1a. Fig. 1b. Fig. 2a. Fig. 2b. PMID:1175077

  8. Interaction of antibody-aggregated C4 and guinea-pig red cells: coagglutination phenomenon of Bordet and Gengou.

    PubMed Central

    Davies, K; Wilson, A B; Coombs, R R

    1981-01-01

    The component of bovine serum (coagglutinogen) responsible for coagglutination of guinea-pig red cells has been shown to be c4, as anticipated from our previously reported findings on human serum. To effect coagglutination, the C4 needs to be aggregated by antibody; thereby probably increasing the avidity of the C4 for the receptors on guinea-pig red cells. The coagglutinating activity is lost if univalent Fab anti-C4 is used, but it can be restored by adding IgG antibody to the Fab. A procedure is described for producing antibody reagents to human or bovine C4 by injecting guinea-pigs with well-washed coagglutinated guinea-pig red cells. PMID:7275174

  9. [Effect produced by the alkaloid fraction of Mimosa tenuiflora (tepescohuite) on the peristaltic reflex of the guinea pig ileum].

    PubMed

    Meckes-Lozoya, M; Lozoya, X; González, J L; Martínez, M

    1990-01-01

    An alkaloidal fraction was obtained from Mimosa tenuiflora (Willd.) Poir (tepescohuite) trunk bark. The product contained mainly an indolealkylamine and three minor alkaloids. This fraction inhibited the peristaltic reflex in the guinea-pig isolated ileum in vitro. PMID:2103706

  10. Inhibition of the effects of thrombin on guinea pig platelets by the diacylglycerol lipase inhibitor RHC 80267

    SciTech Connect

    Amin, D.; Sutherland, C.A.; Khandwala, A.S.; Jamall, I.S.; Kapoor, A.L.

    1986-10-01

    Phospholipase C (PLC) and diacylglycerol lipase (DGL) activities were found in guinea pig platelet microsome preparations. No phospholipase A2 (PLA2) activity was detected. RHC 80267 (1,6-di (0-(carbamoyl) cyclohexanone oxime)hexane) inhibited DGL activity (IC50 = 4 uM) from guinea pig platelet microsomes but had no effect on PLC. RHC 80267 inhibited platelet aggregation (IC50 = 11 uM), release of arachidonic acid (AA), its metabolites, and ATP (IC50 = 4.5 uM) when guinea pig platelets were challenged with a low concentration of thrombin. We propose that PLC-DGL is an important enzymatic pathway for the release of AA in guinea pig platelets.