Characterization in vitro of H+ secretion and H+:Na+ exchange by an organism normally inhabiting a CO2-rich environment: Hymenolepis diminuta (Cestoda) in the rat intestine

1978 ◽  
Vol 56 (11) ◽  
pp. 2344-2354 ◽  
Author(s):  
R. B. Podesta
Keyword(s):  
Metabolic Pathways ◽  
Intestinal Parasite ◽  
Hymenolepis Diminuta ◽  
Ambient Fluid ◽  
Rat Intestine ◽  
Ion Concentrations ◽  
Intracellular Ion Concentrations ◽  
Metabolic Reactions ◽  
Stimulation Of

H+ and Na+ transport by the intestinal parasite Hymenolepis diminuta were studied in vitro. The flatworms acidified the ambient fluid by secreting H+ and the acidification could not be correlated with organic acid excretion. Ambient CO2-independent H+ secretion was attributed to protons of metabolic origin: dephosphorylation reactions and ionization of organic acids within the tissues. Ambient CO2-dependent H+ secretion was attributed to protons produced as a result of the hydration of CO2 within the tissue and to the stimulation of anaerobic metabolic pathways by CO2 acting as a cosubstrate in energy metabolism. Studies in which Na+ uptake was stimulated by CO2 or glucose and inhibited by ouabain, amiloride, or Na+ replacement suggested a partial direct coupling of Na+ absorption and H+ secretion but the different activation energies and the effect of buffer anions other than HCO3− suggested an indirect interaction. Various interactions were considered, including the effect of CO2 and intracellular ion concentrations on metabolic reactions leading to the supply of protons for H+ secretion and energy for ion transport.

Some species differences in the intrinsic factor stimulation of B12 uptake by small intestine in vitro

1959 ◽  
Vol 197 (4) ◽  
pp. 926-928 ◽  
Author(s):  
T. Hastings Wilson ◽  
Elliott W. Strauss
Keyword(s):  
Small Intestine ◽  
Guinea Pig ◽  
Species Differences ◽  
Intrinsic Factor ◽  
Vitamin B ◽  
Guinea Pig Ileum ◽  
Rat Intestine ◽  
Intrinsic Factors ◽  
Stimulation Of

Sacs of everted small intestine from a variety of animals were incubated in bicarbonate-saline containing vitamin B12 with and without intrinsic factor (IF). B12 uptake by rat intestine was stimulated only by its own intrinsic factor. Guinea pig ileum responded to all intrinsic factors tested (guinea pig, rat, hog, hamster, human being and rabbit). The intestines of hamster and rabbit were intermediate in specificity, responding to some, but not all, of the IF preparations. Species differences occur in both the intestine and intrinsic factor preparations. The guinea pig ileum was suggested as a possible assay for both hog and human IF.

Fluorophore toxicity in mouse eggs and zygotes

Zygote ◽  
1998 ◽  
Vol 6 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Karen P. Phillips ◽  
Wen-liang Zhou ◽  
Jay M. Baltz
Keyword(s):  
Membrane Damage ◽  
Fluorescence Excitation ◽  
Ion Concentrations ◽  
Fura 2 ◽  
Quantitative Measurements ◽  
Whole Cell Patch Clamp ◽  
Significant Toxicity ◽  
Intracellular Ion Concentrations ◽  
Mouse Eggs

Ion-sensitive fluorophores are commonly used for quantitative measurements of intracellular ion concentrations. However, both the method of intracellular loading — which for many fluorophores involves endogenous esterase-mediated removal of hydrophobic groups such as acetoxymethyl esters (AM) — and fluorescence excitation of fluorophores in the cell, can produce toxic metabolites and reactive species. Techniques used to measure intracellular ion concentrations in mammalian eggs and embryos are being increasingly employed, yet little information is available about any detrimental effects of the use of fluorophores. We have therefore used in vitro fertilisation (IVF) to assess potential fluorophore toxicity in mouse eggs, and whole cell patch-clamp recordings to detect fluorophore-associated membrane damage in zygotes. Four fluorophores were examined: SNARF-1 and BCECF (pH indicators), Fura-2 (Ca2+) and MQAE (Cl−). Cleavage of AM groups alone had no effect either on the success of IVF or on membrane electrical properties of mouse zygotes. Intracellularly loaded BCECF, SNARF-1 and Fura-2 followed by fluorescence excitation were not cell-toxic under the conditions examined. In contrast, MQAE demonstrated significant toxicity both alone and in combination with fluorescence excitation.

Hymenolepis diminuta: uptake of 5-hydroxytryptamine (serotonin), glucose, and changes in worm glycogen levels

1983 ◽  
Vol 61 (7) ◽  
pp. 1469-1474 ◽  
Author(s):  
Denis Cyr ◽  
S. Gruner ◽  
D. F. Mettrick
Keyword(s):  
Glucose Uptake ◽  
Regional Differences ◽  
Anterior Segment ◽  
Hymenolepis Diminuta ◽  
Stimulatory Action ◽  
Specific Antagonist ◽  
5 Ht Uptake ◽  
Stimulation Of

The effects of 5-hydroxytryptamine (5-HT) and its specific antagonist, methylsergide hydrogenmaleinate, on in vitro glucose uptake by Hymenolepis diminuta were followed for up to 60 min. Maximum stimulation of glucose uptake occurred with 0.5 mM 5-HT. With the addition of 10 mM methysergide (MET) glucose uptake decreased by 68%. Glucose uptake was greatest in the anterior, immature region of the worm strobila, and diminished through the middle to the posterior gravid portion of the strobila. 5-HT significantly increased glucose uptake in all three regions. The addition of 3 mM MET eliminated the stimulatory action of 5-HT on glucose uptake in the anterior and middle regions of the strobila; 10 mM MET significantly reduced glucose uptake in all three regions of the worm. The presence of 0.5 mM 5-HT both stimulated glucose uptake and decreased worm glycogen levels in all three regions of the strobila. The further addition of 0.5 mM MET did not affect the reduced glycogen levels. 5-HT uptake by H. diminuta was over 60% higher in the anterior segment of the strobila compared with uptake in the middle and posterior segments. The addition of 3 mM MET significantly decreased 5-HT uptake in the anterior and middle regions of the strobila; 10 mM MET decreased 5-HT uptake in all three regions. The regional differences in 5-HT and glucose uptake by H. diminuta suggest that the tryptaminergic receptors in the strobila are not equally distributed along the length of the worm. The effects of MET on glucose and 5-HT uptake are in part accountable through its action in blocking 5-HT receptors.

Intestinal Ca and phosphate transport: differential responses to vitamin D3 metabolites.

1977 ◽  
Vol 233 (6) ◽  
pp. E488 ◽  
Author(s):  
M W Walling
Keyword(s):  
Vitamin D ◽  
Phosphate Transport ◽  
Active Metabolites ◽  
Rat Intestine ◽  
Differential Distribution ◽  
Dihydroxyvitamin D3 ◽  
Pi Transport ◽  
Vitamin D3 Metabolites ◽  
Stimulation Of

The transport of Ca and inorganic phosphate (Pi) was studied in the absence of electrochemical gradients across rat intestine in vitro. 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) increased the active absorption of both Ca and Pi in all segments of the small intestine, with changes occurring only in absorptive fluxes, whereas secretory fluxes were unaffected. Active Ca absorption was greatest in the duodenum (greater than jejunum greater than ileum) and active Pi absorption was highest in jejunum (greater than duodenum greater than ileum), in agreement with earlier reports. 24R,25-dihydroxy-vitamin2D3 had similar effects on transport but was less potent. The ratios of Pi absorptive fluxes to Ca absorptive fluxes remained remarkably constant during 80-200% increases in absorption produced by 1,25(OH)2D3, suggesting coupled Ca-Pi transport or coordinate stimulation of Ca and Pi absorptive processes by hormonally active metabolites of vitamin D. The results seem most compatible with a differential distribution of vitamin D-responsive Ca and Pi absorptive cells with a predominance of cells with Ca absorptive sites occurring in duodenum, more Pi absorbing cells in jejunum, and a nearly equal ratio of each type in ileum.

Early Platelet-Collagen Interactions in Whole Blood and Their Modifications by Aspirin and Dipyridamole Evaluated by a New Method (Basic Wave)

1985 ◽  
Vol 54 (04) ◽  
pp. 799-803 ◽  
Author(s):  
José Luís Pérez-Requejo ◽  
Justo Aznar ◽  
M Teresa Santos ◽  
Juana Vallés
Keyword(s):  
Whole Blood ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
White Blood Cells ◽  
Reversible Aggregation ◽  
Inhibitory Compounds ◽  
Rapid Generation ◽  
Stimulation Of ◽  
Collagen Stimulation

SummaryIt is shown that the supernatant of unstirred whole blood at 37° C, stimulated by 1 μg/ml of collagen for 10 sec, produces a rapid generation of pro and antiaggregatory compounds with a final proaggregatory activity which can be detected for more than 60 min on a platelet rich plasma (PRP) by turbidometric aggregometry. A reversible aggregation wave that we have called BASIC wave (for Blood Aggregation Stimulatory and Inhibitory Compounds) is recorded. The collagen stimulation of unstirred PRP produces a similar but smaller BASIC wave. BASIC’s intensity increases if erythrocytes are added to PRP but decreases if white blood cells are added instead. Aspirin abolishes “ex vivo” the ability of whole blood and PRP to generate BASIC waves and dipyridamole “in vitro” significantly reduces BASIC’s intensity in whole blood in every tested sample, but shows little effect in PRP.

DER EINFLUSS VON RESERPIN AUF DIE ANTITHYREOIDALE WIRKUNG VON KALIUMPERCHLORAT

1962 ◽  
Vol 39 (3) ◽  
pp. 423-430
Author(s):  
H. L. Krüskemper ◽  
F. J. Kessler ◽  
E. Steinkrüger
Keyword(s):  
Thyroid Gland ◽  
Male Rats ◽  
Normal Male ◽  
Tissue Respiration ◽  
List Type ◽  
Morphological Alterations ◽  
Hormone Synthesis ◽  
Stimulation Of

ABSTRACT 1. Reserpine does not inhibit the tissue respiration of liver in normal male rats (in vitro). 2. The decrease of tissue respiration of the liver with simultaneous morphological stimulation of the thyroid gland after long administration of reserpine is due to a minute inhibition of the hormone synthesis in the thyroid gland. 3. The morphological alterations of the thyroid in experimental hypothyroidism due to perchlorate can not be prevented with reserpine.

EFFECT OF ACTINOMYCIN D ON TSH-INDUCED STIMULATION OF THYROIDAL PROTEIN SYNTHESIS IN THE RAT

1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar
Keyword(s):  
Protein Synthesis ◽  
Actinomycin D ◽  
The Other ◽  
Leucine Incorporation ◽  
Short Term ◽  
Other Hand ◽  
Thyroid Glands ◽  
Translational Level ◽  
Stimulation Of

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.

Sign in / Sign up

Export Citation Format

Share Document