OESTROGEN-PROGESTERONE RELATIONSHIPS IN THE INDUCTION OF OESTRUS IN SPAYED HEIFERS

1969 ◽  
Vol 45 (1) ◽  
pp. 99-109 ◽  
Author(s):  
M. J. CARRICK ◽  
J. N. SHELTON
Keyword(s):  
Behavioural Response ◽  
Normal Response ◽  
Oestradiol Benzoate ◽  
Small Doses ◽  
Refractory State ◽  
Increased Sensitivity ◽  
Repeated Doses ◽  
Effective Doses ◽  
Response Line ◽  
Normal Sensitivity

SUMMARY Experiments were conducted to examine the behavioural response of spayed heifers to oestrogen, and its modification by progesterone. In two groups of heifers, the median effective doses (MED) of oestradiol benzoate (ODB) were 121 and 132 μg. Repeated doses of ODB at physiological levels did not induce a state of refractoriness; in this respect the heifer is dissimilar to the ewe. However, repeated doses of 10 mg. ODB induced refractoriness to 400 μg. ODB. When such refractory heifers were treated with 10 mg. progesterone/day for 5 days, they showed a normal response to 400 μg. ODB given 3 days later. This return to normal sensitivity was not sustained, and pretreatment with progesterone was necessary for a normal response to subsequent small doses of ODB. The transient removal of the refractory state appears not to be due to a simple synergistic effect of residual progesterone, but to an effect of preconditioning a neural centre to respond to oestrogen. Increasing the duration of pretreatment with progesterone beyond 5 days did not result in a greater sensitivity to ODB. Pretreatment with progesterone in heifers not made refractory to ODB did not result in an increased sensitivity to ODB. Moreover, up to 7 days after termination of the progesterone treatment, the response to ODB was reduced and the slope of the dose-response line was less steep than when ODB was injected alone. The reduction of the response was more pronounced with 40 mg. progesterone/day than with 10 mg. The possible significance of these results in intact animals is discussed.

Inhibition of nitric oxide synthase gene expression in vivo and in vitro by repeated doses of endotoxin

1996 ◽  
Vol 271 (4) ◽  
pp. G539-G548 ◽  
Author(s):  
C. C. Chang ◽  
C. C. McCormick ◽  
A. W. Lin ◽  
R. R. Dietert ◽  
Y. J. Sung
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Molecular Mechanisms ◽  
Endotoxin Tolerance ◽  
Refractory State ◽  
Repeated Doses ◽  
Normal Sensitivity ◽  
Oxide Synthase

We have examined the effects of repeated endotoxin administration in vivo and in vitro on the induction of nitric oxide synthase (NOS). In vivo, hepatic NOS activity and mRNA were increased markedly by the administration of Escherichia coli lipopolysaccharide (LPS). The change in hepatic NOS activity coincided with a marked accumulation of hepatic citrulline. Both enzyme activity and citrulline concentration returned to normal by 12 h after LPS administration. At this time, a subsequent administration of endotoxin caused no change in either NOS mRNA, NOS activity, or citrulline concentration, and thus an endotoxin-refractory state for nitric oxide (NO) synthesis was established. Normal sensitivity was reestablished by 24 h after the initial dose. In vitro studies using both a macrophage cell line (HD11) and primary macrophages indicated that LPS pretreatment caused cells in culture to become completely refractory to subsequent stimulation by LPS. Finally, we tested the hypothesis that NO may be involved in the development of the refractory state. Various inhibitors blocked the initial synthesis of NO by > 90% but failed to influence the development of the refractory state. Our study demonstrates both in vivo and in vitro that NO synthesis is completely blocked after repeated exposure to endotoxin by a mechanism that appears to be pretranslational. This model of early endotoxin tolerance may provide insight into the molecular mechanisms that regulate expression of the NOS gene.

EFFECTS OF OESTRADIOL AND PROGESTERONE ON THE INDUCTION AND DURATION OF SEXUAL RECEPTIVITY IN CYCLIC FEMALE RATS

1977 ◽  
Vol 74 (3) ◽  
pp. 477-485 ◽  
Author(s):  
P. SÖDERSTEN ◽  
S. HANSEN
Keyword(s):  
Behavioural Response ◽  
Female Rats ◽  
Sexual Receptivity ◽  
Repeated Treatment ◽  
Progesterone Treatment ◽  
Oestradiol Benzoate

SUMMARY Intact 4-day cyclic rats showed sexual receptivity 24 h after an injection of oestradiol benzoate (OB) on any day of the cycle except on the second day after the display of spontaneous oestrus. Ovariectomy at the time of OB treatment abolished the behavioural response, but receptivity was restored by progesterone. Progesterone treatment early on the day of behavioural oestrus advanced the display of receptivity but did not affect the time at which oestrus ended. Repeated treatment of sexually receptive rats with progesterone did not affect the duration of oestrus. These results show that sexual receptivity in the intact rat cannot occur in the absence of oestradiol and progesterone. The results further suggest that progesterone may not be associated with the mechanisms terminating behavioural oestrus in rats. Treatment with OB on the day of oestrus can prolong the duration of receptivity but only at a higher dosage than that needed for induction of receptivity.

Role of endothelium-derived relaxing factors in the renal response to vasoactive agents in hypothyroid rats

2003 ◽  
Vol 285 (1) ◽  
pp. E182-E188 ◽  
Author(s):  
Juan Manuel Moreno ◽  
Rosemary Wangensteen ◽  
Juan Sainz ◽  
Isabel Rodríguez-Gomez ◽  
Virginia Chamorro ◽  
...  
Keyword(s):  
Vascular Reactivity ◽  
Ang Ii ◽  
Vasoactive Agents ◽  
Normal Response ◽  
No Donor ◽  
Increased Sensitivity ◽  
Renal Vascular ◽  
And Control ◽  
Renal Responses

This study analyzed the role of nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) in the abnormal renal vascular reactivity of hypothyroid rats. Renal responses to vasoconstrictors [VC: phenylephrine (PHE) and ANG II] and vasodilators [VD: ACh, sodium nitroprusside (SNP), and papaverine (PV)] were studied in kidneys from control and hypothyroid rats under normal conditions and after NO or EDHF blockade. NO was blocked by the administration of Nω-nitro-l-arginine methyl ester (l-NAME) and EDHF by the administration of tetraethylammonium (TEA) or by an increased extracellular K+. The response to VC was also evaluated after endothelium removal. Hypothyroid kidneys showed reduced responsiveness to PHE and a normal response to ANG II. l-NAME and TEA administration produced an increased sensitivity to PHE and to ANG II in control preparations. l-NAME also increased the response to PHE in hypothyroid kidneys, but the differences between control and hypothyroid kidneys were maintained. TEA administration did not change the response to either VC in hypothyroid preparations. In endothelium-removed preparations, TEA was unable to increase pressor responsiveness to VC. Hypothyroid kidneys showed reduced responsiveness to ACh and SNP and normal response to PV. The differences between hypothyroid and control preparations in the responses to ACh and SNP were maintained after l-NAME or increased K+. In conclusion, this study shows that 1) the attenuated response to PHE in hypothyroidism is not related to an increased production of endothelium-derived relaxing factors NO and EDHF; 2) the response to VC in hypothyroid preparations is insensitive to EDHF blockade; and 3) hypothyroid preparations have a reduced reactivity to the NO donor, and NO-independent vasodilatation remains unaffected.

scholarly journals G-6-PD Long Prairie: a new glucose-6-phosphate dehydrogenase mutant exhibiting normal sensitivity to inhibition by NADPH and accompanied by nonspherocytic hemolytic anemia

Blood ◽  
1977 ◽  
Vol 49 (2) ◽  
pp. 247-251 ◽  
Author(s):  
GJ Johnson ◽  
ME Kaplan ◽  
E Beutler
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Alternative Mechanism ◽  
Ph Optimum ◽  
Intracellular Enzyme ◽  
Chronic Hemolysis ◽  
Increased Sensitivity ◽  
Normal Sensitivity ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Heat Instability

Abstract The enzymatic properties of a new glucose-6-phosphate dehydrogenase (G- 6-PD) variant (G-6-PD Long Prairie) were studied in a white patient with chronic nonspherocytic hemolysis. The red cells were found to have 2.3%-7.7% normal enzymatic activity. The mutant enzyme exhibited marked heat instability, an increased pH optimum, a moderately decreased Km for G-6-P, and increased utilization of 2-deoxyglucose-6-phosphate and deamino NADP. The Km for NADP and Ki for NADPH were both normal. G-6-PD Long Prairie is an interesting new G-6-PD variant that demonstrates that chronic hemolysis can be associated with modestly decreased G-6-PD activity despite normal sensitivity to inhibition by NADPH. Although increased sensitivity to inhibition by NADPH has been postulated to decrease intracellular enzyme activity, resulting in enhanced susceptibility to hemolysis in certain G-6-PD variants with only moderately decreased enzymatic activity, an alternative mechanism of hemolysis, possibly enzyme thermolability, exists in G-6-PD Long Prairie.

QUANTITATIVE STUDIES ON THE HORMONAL INDUCTION OF OESTRUS IN SPAYED EWES

1955 ◽  
Vol 12 (3) ◽  
pp. 163-173 ◽  
Author(s):  
T. J. ROBINSON
Keyword(s):  
Hormonal Control ◽  
Behaviour Pattern ◽  
Physiological Changes ◽  
Quantitative Studies ◽  
Oestradiol Benzoate ◽  
Endogenous Oestrogen ◽  
The Mean ◽  
The Difference ◽  
Response Line ◽  
Mean Time

SUMMARY Seven trials were conducted with sixty-nine ovariectomized Suffolk cross-bred ewes to determine the requirements of oestradiol benzoate (ODB), given alone or preceded by 75 mg progesterone (6 × 12·5 mg in oil over 3 days, followed 2 days later by oestrogen), for oestrous behaviour and characteristic vaginal changes. Progesterone pretreatment resulted in a marked increase of sensitivity to oestrogen. For oestrus, the respective values of the median effective dose (ED 50) for ODB preceded by progesterone and for ODB alone were 22 and 64 μg, the difference being significant (P<0·001). The 99% fiducial limits associated with these estimates were respectively 19 and 26 μg and 52 and 81 μg. For vaginal changes the corresponding values were 10-14-17 and 20-24-28 (P<0·001). Progesterone pretreatment resulted in an apparently steeper dose-response line for oestrus, and advanced the mean time of onset by about 12 hr. The behaviour pattern following progesterone—ODB appeared to differ from that following ODB alone. Oestrus in the ewe appears to be under dual hormonal control. Endogenous oestrogen production is insufficient to induce the full psychic and physiological changes associated with normal oestrus, unless the animal has been conditioned previously by progesterone.

scholarly journals Increased Sensitivity of DMD Lymphoblastoid Cell To Low Doses of X-Irradiation

1994 ◽  
Vol 12 (2) ◽  
pp. 99-107
Author(s):  
L. Melchiorri ◽  
S. Carturan ◽  
D. Ferrari ◽  
F. Di Virgilio ◽  
O. R. Baricordi
Keyword(s):  
Cellular Membrane ◽  
Peripheral Blood Lymphocytes ◽  
Lymphoid Cells ◽  
Cellular Phenotype ◽  
Ca Uptake ◽  
Small Doses ◽  
X Irradiation ◽  
Increased Sensitivity ◽  
Cell Cycle Length ◽  
Membrane Defect

Several cell membrane abnormalities affecting various cell populations have been reported in Duchenne muscular dystrophy (DMD) by different investigators. In peripheral blood lymphocytes intrinsic cellular membrane defect evidentiated by impairment of capping capacities has been repeatedly obtained, suggesting that DMD product could act in such cellular phenotype at the cytoskeletal compartment. It has been previously reported that lymphoid cells are characterized by high radiosensitivity. On the assumption that DMD phenotypes could increase this susceptibility, we have compared the radiosensitivity of normal and DMD lymphoblastoid cell lines (LCLs) to small doses (0-2Gy) of x-irradiation. The results obtained suggest an increased sensitivity of DMD cells without Ca++ uptake or apoptotic phenomena, associated with an effect upon cell cycle length.

THE ASSAY OF CORTICOTROPHIN IN MICE

1963 ◽  
Vol 44 (2) ◽  
pp. 237-249 ◽  
Author(s):  
Claus Rerup ◽  
Pavo Hedner
Keyword(s):  
Subcutaneous Administration ◽  
Small Sample ◽  
Lower Body ◽  
Sample Analysis ◽  
Lower Body Weight ◽  
Increased Sensitivity ◽  
The Mean ◽  
The Difference ◽  
Response Line ◽  
Free Plasma

ABSTRACT The assay of corticotrophin was performed in mice by means of small sample analysis of free plasma corticosteroids. In this method hypophysectomy was replaced by dexamethasone pretreatment. The response was measured preferably in a single mouse weighing 20 g or more. When mice of a lower body weight were used the plasma of two randomly assigned mice was pooled. Corticosteroids (mainly corticosterone) were determined fluorometrically in 0.25 (0.20) ml samples of plasma from heparinized blood. The results show that valid corticotrophin assays can be performed in mice both by the intravenous and subcutaneous route. Compared with the adrenal ascorbic acid depletion method or the plasma corticosteroid method in the rat the assay in mice was found to be at least five times more sensitive. 40 micro-units of corticotrophin were consistently detectable. Precision was dependent on the route of administration, the mean index of precision (s/b) being 0.20 in the intravenous and 0.12 in the subcutaneous assay. The difference was due to a steeper slope of the logdose-response line after subcutaneous administration. Contrary to the findings in the rat, corticotrophin A (oxycel purified) did not differ significantly in potency estimates from subcutaneous and intravenous assays in mice, when crude corticotrophin (U. S. P. Corticotropin Reference Standard) was the basis of comparison. Accordingly results of subcutaneous assays of corticotrophin A samples in terms of the U. S. P. standard were lower in mice than in rats. The use of gelatine instead of saline as diluent in the subcutaneous assays yielded slightly but not significantly higher potency estimates (25 per cent). The interpretation of the results is that for intravenous corticotrophin assays the mouse method is comparable to the rat assay. For subcutaneous corticotrophin assays, however, the mouse method is not suitable, if crude corticotrophin (U. S. P. standard) is the basis of comparison, but if corticotrophin A (oxycel purified) is the standard of reference (e. g. the Third International Standard for Corticotrophin), the mouse method may justifiably be used. The advantages of the mouse method are increased sensitivity, precision, convenience, and economy.

scholarly journals Long-term investigation of 137Cs and 134Cs in drinking water in the city of Zagreb, Croatia

Nukleonika ◽  
2020 ◽  
Vol 65 (3) ◽  
pp. 193-198
Author(s):  
Zdenko Franić ◽  
Gina Branica ◽  
Branko Petrinec ◽  
Gordana Marović
Keyword(s):  
Drinking Water ◽  
Water Contamination ◽  
Activity Ratio ◽  
Critical Pathway ◽  
Activity Concentrations ◽  
Small Doses ◽  
Effective Doses ◽  
Fukushima Daiichi ◽  
The City

AbstractThis paper presents the results of long-term investigations of 137Cs and 134Cs activity concentrations in drinking water in the city of Zagreb for the period 1987–2018. The highest activity concentrations of both radio-nuclides were measured in 1987, decreasing exponentially ever since, while 134Cs in several subsequent years fell under the detection limit. After the Fukushima Daiichi accident in 2011, the presence of 134Cs in drinking water was detected again. The environmental residence time for 137Cs was estimated to be 8.1 years in drinking water and 5.7 years in fallout. The correlation between 137Cs in fallout and in drinking water is very good, and this indicates that fallout is the main source of water contamination. The observed 134Cs/137Cs activity ratio in drinking water for the post-Chernobyl period was similar to the ratio found in other environmental samples. The estimation of annual effective doses received by the adult members of the Croatian population due to the intake of radiocaesium in drinking water showed quite small doses of 0.28 μSv in 1987 decreasing to 2.5 nSv in 2018, which indicated that drinking water was not a critical pathway for the transfer of radiocaesium to humans.

scholarly journals Separation of the acetylcholinesterase-deficient red cells in paroxysmal nocturnal hemoglobinuria

Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 893-897 ◽  
Author(s):  
FL Chow ◽  
SE Hall ◽  
WF Rosse ◽  
MJ Telen
Keyword(s):  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Fluid Phase ◽  
Abnormal Cells ◽  
Increased Sensitivity ◽  
Cell Affinity ◽  
Membrane Defects ◽  
Mixed Populations ◽  
Normal Sensitivity ◽  
I Cells ◽  
Complement Lysis

Blood of patients with paroxysmal nocturnal hemoglobinuria (PNH) most often contains two or more populations of erythrocytes--one population with normal sensitivity to lysis by complement (PNH I cells) and a second population of moderately abnormal cells (PNH II cells) or markedly abnormal cells (PNH III cells). PNH II and III cells exhibit moderately and markedly increased sensitivity to lysis by complement, respectively, as well as other membrane defects. We have devised a method for isolating pure, intact PNH II and III cells from mixed populations by use of monoclonal antibodies and cell affinity chromatography. Study of purified cell populations has led to the identification of a further subtype, PNH IIIb, of PNH erythrocytes. PNH IIIb erythrocytes are less sensitive to complement lysis than PNH IIIa cells but are lysed by fluid-phase activation of complement, unlike PNH II erythrocytes.

BAY i 7351, A New Platelet Inhibitor, and antithrombotic Compound

1979 ◽  
Author(s):  
F. Seuter ◽  
W.D. Busse ◽  
U. Hoerlein ◽  
H. Boeshagen ◽  
F. Hoffmeister ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Jugular Vein ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Minimal Effective Dose ◽  
Platelet Inhibitor ◽  
Small Doses ◽  
Effective Doses ◽  
Platelet Functions

4,4′ -Dichloro-N ,N′ -bis [( 1 -methyl-4-piperidinyl) -methyl] -2,2′ di thiobisbenzamide = BAY i 7351 was tested in animal models (rat and rabbit) of traumatically induced thrombosis. After prophylactic administration of small doses of BAY i 7351 (0.3 mg/kg p.o.) to rats the thrombus formation is inhibited (p < 0.05) both in the arterial and the venous system by 79% and 57%, respectively. Further on thrombi already formed (20 and 24 hold) are reduced in weight. The minimal effective doses of these thrombolytic effects in rats are 2 mg/kg p.o. in the carotid artery, and 6 mg/ kg p.o. in the jugular vein, when administered in two single doses of 1 and 3 mg/ kg. The compound is not an anticoagulant or a fibrinolytic drug. It is an inhibitor of platelet aggregation - induced with various aggregating agents including ADP -, in vitro with minimal effective concentrations in the range of 1-10 μg/ml as well as ex vivo (minimal effective dose: 3-10 mg/ kg p.o., rat). Further investigations as to v arious platelet functions, influence on thromboxane and prostacyclin formation will be reported separately. BAY i 7351 is a compound with properties which are considered favourable for treatment of thromboembolic diseases.

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