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

The effect of antigen challenge on the function of neuronal M2-muscarinic autoreceptors in the lungs was studied in anesthetized guinea pigs. Guinea pigs were injected intraperitoneally with saline (control group) or ovalbumin (10 mg/kg) on days 1, 3, and 5. One group of sensitized animals was challenged on days 20–25 with aerosolized ovalbumin for 5 min/day (challenged group), while another group of the sensitized animals was not challenged (sensitized group). On day 26 the animals were anesthetized, paralyzed, tracheostomized, and artificially ventilated. Pulmonary inflation pressure (Ppi), tidal volume, blood pressure, and heart rate were recorded. Both vagus nerves were cut, and electrical stimulation of the distal portions caused bronchoconstriction (measured as an increase in Ppi) and bradycardia. In the control group, pilocarpine (1–100 micrograms/kg iv) attenuated vagally induced bronchoconstriction by stimulating inhibitory M2-muscarinic receptors on parasympathetic nerves in the lungs. Conversely, blockade of these receptors with the antagonist gallamine (0.1–10 mg/kg iv) produced a marked potentiation of vagally induced bronchoconstriction. These results confirm previous findings. In the challenged guinea pigs, pilocarpine did not inhibit vagally induced bronchoconstriction. Furthermore, gallamine did not potentiate vagally induced bronchoconstriction to the same degree as in the controls. In the group of animals that was sensitized but not challenged, the potentiation of vagally induced bronchoconstriction by gallamine was identical to the controls. There was no increase in baseline Ppi in the sensitized or challenged animals compared with the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Download Full-text

Neural Responses to Electrical Stimulation of the Cochlea in Guinea Pigs

Auris Nasus Larynx ◽

10.1016/s0385-8146(12)80081-2 ◽

1994 ◽

Vol 21 (4) ◽

pp. 201-208

Author(s):

Jun-Ichi Matsushima ◽

Chihiro Harada ◽

Noboru Sakai ◽

Tohru Ifukube ◽

Makoto Takahashi

Keyword(s):

Electrical Stimulation ◽

Guinea Pigs ◽

Neural Responses ◽

Stimulation Of

Download Full-text

Immunological regulation of colonic ion transport

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1989.256.2.g396 ◽

1989 ◽

Vol 256 (2) ◽

pp. G396-G403 ◽

Cited By ~ 4

Author(s):

D. A. Russell ◽

G. A. Castro

Keyword(s):

Guinea Pigs ◽

Trichinella Spiralis ◽

Short Circuit ◽

Short Circuit Current ◽

Antigenic Stimulation ◽

Synthesis Inhibitor ◽

Combined Use ◽

Maximum Elevation ◽

Prostaglandin Synthesis Inhibitor ◽

Stimulation Of

Challenge of distal colonic epithelium from Trichinella spiralis-infected guinea pigs with parasite-derived antigen elevated short-circuit current (Isc) for approximately 60 min. The maximum elevation (delta Isc) was approximately 250 microA/cm2 at 5 min after the addition of trichinella antigen. The antigen-induced alterations in Isc were of greater magnitude and duration than those evoked in jejunum. Colonic electrical resistance was transiently reduced after exposure to antigen. There was no significant effect of antigen on electrical parameters of colon from nonimmunized (uninfected) guinea pigs. The antihistamine pyrilamine (10(-5) M) and the prostaglandin synthesis inhibitor indomethacin (10(-6) M) reduced the colonic Isc response to antigen by 40% when used in combination but had insignificant effects when used singly. In contrast, the jejunal Isc response to antigen was totally eliminated by the combined use of those inhibitors. Antigenic stimulation of sensitized colon released histamine and prostaglandin E2 (PGE2). However, the histamine released was only about one-tenth that stimulated by antigen in the jejunum, and PGE2 released was only one-tenth of that stimulated by bradykinin in the colon. PGE2 was not released after antigenic stimulation of jejunum. The antigen-induced colonic delta Isc was reduced approximately 50% by either furosemide or tetrodotoxin. Although histamine- and indomethacin-sensitive factors contribute greatly to the mediation of the antigen-induced delta Isc in jejunum, these autacoids contribute to a lesser extent to the antigen-induced delta Isc in guinea pig colon.

Download Full-text

STUDIES ON THE EFFECTS OF PHAGOCYTIC STIMULATION ON MICROBIAL DISEASE: V. STIMULATION OF PHAGOCYTIC ACTIVITY OF MONOCYTES AGAINST TUBERCLE BACILLI, STRAIN BCG

Canadian Journal of Biochemistry and Physiology ◽

10.1139/y56-062 ◽

1956 ◽

Vol 34 (1) ◽

pp. 571-579

Author(s):

Béla Gözsy ◽

László Kátó

Keyword(s):

Phagocytic Activity ◽

Guinea Pigs ◽

Saline Solution ◽

Defense Mechanism ◽

Direct Action ◽

Intraperitoneal Administration ◽

Cellular Defense ◽

Appropriate Treatment ◽

Stimulation Of

Monocytes were obtained by the washing of the peritoneal cavity of guinea pigs with Hanks' solution six days after intraperitoneal administration of a saline solution containing glycogen. Phagocytosis of tubercle bacilli (BCG strain) was studied after a one hour incubation at 37 °C. under the influence of histamine and 1,4-dimethyl-7-isopropyl-bicyclo-decapentane, which latter substance had shown a beneficial influence on the outcome of experimental tuberculosis. Histamine increased the phagocytic activity of monocytes, within the limits of 1 μgm. to 10 μgm per ml. This stimulation was inhibited in vitro by a synthetic antihistamine substance. Fifty and 100 μgm. per ml. histamine decreased the phagocytosis of tubercle bacilli (BCG) by the monocytes. Monocytes withdrawn from histamine treated guinea pigs showed no stimulated activity. From 0.5 to 100 μgm. per ml. of 1,4-dimethyl-7-isopropylbicyclo-decapentane stimulated the phagocytic activity of monocytes against tubercle bacilli (BCG) in vitro and monocytes withdrawn from animals treated with the same substance showed equally a stimulated activity. This increased phagocytosis was equally inhibited in vitro by the antihistamine, but to a lesser degree than the inhibition of the histamine stimulated phagocytosis. The above observations suggest that the stimulating action of the 1,4-dimethyl-7-isopropyl-bicyclo-decapentane is a direct action on the monocytes rather than an indirect one caused by activation of latent histamine. Experiments also show the possibility of stimulation of the cellular defense mechanism, by appropriate treatment.

Download Full-text

Efferent-mediated protection from acoustic overexposure: relation to slow effects of olivocochlear stimulation

Journal of Neurophysiology ◽

10.1152/jn.1995.73.2.506 ◽

1995 ◽

Vol 73 (2) ◽

pp. 506-514 ◽

Cited By ~ 102

Author(s):

E. R. Reiter ◽

M. C. Liberman

Keyword(s):

Electrical Stimulation ◽

Inner Ear ◽

Guinea Pigs ◽

Threshold Shift ◽

Exposure Condition ◽

Protective Effects ◽

Acoustic Overstimulation ◽

Different Levels ◽

Stimulation Of

1. The present study attempts to resolve discrepancies in the reported role of olivocochlear (OC) efferent activation in protecting the inner ear from acoustic overstimulation: in previous studies, activating the OC system in guinea pigs reduced the threshold shift caused by 1 min monaural exposure to a 10-kHz tone; whereas unilateral OC activation in cats had no effect on threshold shifts following binaural exposure to a 10 min 6-kHz tone. 2. In this study, anesthetized and curarized guinea pigs were exposed either monaurally or binaurally to tones of different duration (1-5 min), frequency (6 to 10 kHz) and intensity (105-118 dB SPL). For each exposure condition, threshold shifts were compared among ears with different levels of OC activation: in some cases, the OC bundle (OCB) was electrically stimulated during (and/or before) the acoustic overexposure; in others, the OCB was cut before the exposure; in control cases, the OCB was neither cut nor electrically stimulated. 3. Electrical stimulation of the OCB delivered simultaneously with acoustic overstimulation produced significant reductions in threshold shift only for acoustic exposures at higher frequencies (8 and 10 kHz) and shorter durations (1 and 2 min). The protective effects on 1-min exposures could be extinguished by prior stimulation of the OCB, i.e., if the OC stimulation was turned on 4 min before the acoustic overexposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Download Full-text

Dietary calcium and phosphate restriction in guinea-pigs during pregnancy: fetal mineralization induces maternal hypocalcaemia despite increased 1α,25-dihydroxycholecalciferol concentrations

British Journal Of Nutrition ◽

10.1017/s000711450000180x ◽

2000 ◽

Vol 84 (4) ◽

pp. 495-504 ◽

Cited By ~ 7

Author(s):

Katrien Rummens ◽

Erik Van Herck ◽

Rita van Bree ◽

Roger Bouillon ◽

F. André Van Assche ◽

...

Keyword(s):

Guinea Pig ◽

Guinea Pigs ◽

Plasma Concentrations ◽

Dual Energy ◽

Whole Body ◽

Hydroxylase Activity ◽

Mineral Density ◽

X Ray ◽

Highly Correlated ◽

Stimulation Of

Guinea-pig fetuses at term are mineralized to a degree comparable with human fetuses, which makes the guinea-pig an attractive animal model to study maternal–fetal interactions with regard to Ca and phosphate (P) homeostasis. We studied non-pregnant and pregnant (day 57) vitamin D-replete guinea-pigs, fed either a normal guinea-pig chow with 9·6 g Ca/kg and 4·9 g P/kg or a study diet with 2 g Ca/kg and 1 g P/kg (low-Ca–P diet) for 7–8 weeks. Both pregnancy and the low-Ca–P diet decreased plasma concentrations of 25-hydroxycholecalciferol (25(OH)D3), but increased total and free 1α,25-dihydroxycholecalciferol (1,25(OH)2D3), strongly suggesting an additive stimulation of 1α-hydroxylase activity. Maternal and fetal 25(OH)D3and 1,25(OH)2D3levels were highly correlated (r0·82 and 0·92 respectively, P<0·001). Dual-energy absorption X-ray absorptiometry (DXA) showed that both pregnancy and the low-Ca–P diet decreased bone mineral density (BMD) of the maternal femur, particularly at the distal metaphysis. Despite higher 1,25(OH)2D3concentrations and lower BMD, pregnant animals on the low-Ca–P diet were hypocalcaemic; blood Ca2+levels were inversely correlated with the number of fetuses in this group (r-0·93, P<0·001). Fetal growth as well as mineralization (assessed by whole-body and femoral DXA, bone histomorphometry and plasma–bone osteocalcin measurements) were unaltered in the low-Ca–P group. In conclusion, fetal mineralization proceeds normally but induces maternal hypocalcaemia in guinea-pigs with dietary restriction of Ca and P.

Download Full-text