Partial purification of a hypertensive substance from rat erythrocytes

1985 ◽  
Vol 63 (10) ◽  
pp. 1321-1326 ◽  
Author(s):  
William D. McCumbee ◽  
Gary L. Wright
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Calcium Uptake ◽  
Specific Activity ◽  
Present Report ◽  
Fold Increase ◽  
Partial Purification ◽  
Rat Erythrocytes ◽  
In Vitro Effects

A crude extract prepared from rat erythrocytes was previously shown to contain an active component (hypertensive factor, HF) that stimulates the in vitro uptake of calcium by aortic rings and causes a sustained and severe elevation in systolic blood pressure in normotensive rats. The present report demonstrates that the in vitro effects of HF on calcium uptake are concentration dependent and reversible, and that these effects on calcium uptake provide a convenient bioassay for monitoring the purification of HF. HF was prepared from a diffusate obtained by dialyzing hemolyzed rat erythrocytes. The diffusate was applied successively to molecular sieve and anion exchange columns resulting in a 1500-fold increase in specific activity relative to the starting hemolysate. The compound stimulating calcium uptake was found to be heat stable and resistant to digestion with trypsin and chymotrypsin. In contrast, treatment with pronase E, a nonspecific protease, markedly increased the calcium transport stimulatory activity. The administration of the purified preparation to normotensive rats having a systolic blood pressure of 118 ± 2 Torr (1 Torr = 133.322 Pa) resulted in a significant elevation of blood pressure (171 ± 11 Torr) by day 5. The severity of this increase further suggests that there is a marked enhancement in potency relative to earlier fractions that were examined. Perhaps most importantly, these results indicate that, at this stage of purification, the pressor component and the calcium-stimulatory component of HF appear to co-purify.

An antihypertensive extract of erythrocytes: effects on 45Ca uptake and efflux

1986 ◽  
Vol 64 (4) ◽  
pp. 424-429
Author(s):  
G. L. Wright ◽  
G. O. Rankin ◽  
W. D. McCumbee
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Calcium Uptake ◽  
Slow Component ◽  
Present Report ◽  
Calcium Stores ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Washout Curves

The present report describes some aspects of the effects of a recently described antihypertensive extract of erythrocytes (AHF) on calcium uptake and efflux in rat aortae. AHF was found to be present in the erythrocytes of both spontaneously hypertensive rats and normotensive rats. Furthermore, AHF obtained from erythrocytes of SH rats was shown to be equally effective in suppressing lanthanum-resistant calcium uptake in aortae from hypertensive and normotensive rats. AHF treatment prior to incubation of aortae with 45Ca caused an apparent increase in the total 45Ca uptake. The analysis of calcium washout curves obtained for tissue in calcium-free or lanthanum-containing media indicated that AHF had no significant effect on the rate of calcium loss from the slow component of efflux, though this compartment tended to be reduced in size. This indicated that the increase in the 45Ca content of AHF-exposed aortae prior to rinsing was confined to the rapid component of efflux. The loss of calcium from the rapidly exchanging compartment was enhanced in either of the efflux media used. The results suggest that a principal action of AHF involves an increase in the lability and exchangeability of calcium stores. In addition to its effects in resting tissue, AHF abolished the increase in lanthanum-resistant calcium uptake induced in rat aortae by the addition of high K+ or norepinephrine to the incubation media. In a second part of the study, the effect of AHF on blood pressure and in vitro calcium uptake were compared with that of phosphatidylethanolamine (PEA), the probable identity of another endogenous antihypertensive (renin preinhibitor) compound earlier shown to share important functional similarities with AHF. The results reduce the likelihood that the two causal agents are identical. The AHF produced a significant (75 Torr, 1 Torr = 133.32 Pa) fall in the systolic blood pressure (SBP) of spontaneously hypertensive rats within 24 h following injection, whereas PEA had no effect on the SBP in this model. Both AHF and PEA reduced the resting in vitro uptake of "lanthanum-resistant" calcium in rat aortic segments. However, the AHF effect was significantly greater than PEA at each concentration studied.

scholarly journals In Vitro,In Vivo, and Clinical Studies of Tedizolid To Assess the Potential for Peripheral or Central Monoamine Oxidase Interactions

2013 ◽  
Vol 57 (7) ◽  
pp. 3060-3066 ◽  
Author(s):  
S. Flanagan ◽  
K. Bartizal ◽  
S. L. Minassian ◽  
E. Fang ◽  
P. Prokocimer
Keyword(s):  
Blood Pressure ◽  
Monoamine Oxidase ◽  
Clinical Research ◽  
Systolic Blood Pressure ◽  
Clinical Studies ◽  
Geometric Mean ◽  
Interaction Study ◽  
Mao B ◽  
Mao A

ABSTRACTTedizolid phosphate is a novel oxazolidinone prodrug whose active moiety, tedizolid, has improved potency against Gram-positive pathogens and pharmacokinetics, allowing once-daily administration. Given linezolid warnings for drug-drug and drug-food interactions mediated by monoamine oxidase (MAO) inhibition, including sporadic serotonergic toxicity, these studies evaluated tedizolid for potential MAO interactions.In vitro, tedizolid and linezolid were reversible inhibitors of human MAO-A and MAO-B; the 50% inhibitory concentration (IC50) for tedizolid was 8.7 μM for MAO-A and 5.7 μM for MAO-B and 46.0 and 2.1 μM, respectively, with linezolid. Tedizolid phosphate was negative in the mouse head twitch model of serotonergic activity. Two randomized placebo-controlled crossover clinical studies assessed the potential of 200 mg/day tedizolid phosphate (at steady state) to enhance pressor responses to coadministered oral tyramine or pseudoephedrine. Sensitivity to tyramine was determined by comparing the concentration of tyramine required to elicit a ≥30-mmHg increase in systolic blood pressure (TYR30) when administered with placebo versus tedizolid phosphate. The geometric mean tyramine sensitivity ratio (placebo TYR30/tedizolid phosphate TYR30) was 1.33; a ratio of ≥2 is considered clinically relevant. In the pseudoephedrine study, mean maximum systolic blood pressure was not significantly different when pseudoephedrine was coadministered with tedizolid phosphate versus placebo. In summary, tedizolid is a weak, reversible inhibitor of MAO-A and MAO-Bin vitro. Provocative testing in humans and animal models failed to uncover significant signals that would suggest potential for hypertensive or serotonergic adverse consequences at the therapeutic dose of tedizolid phosphate. Clinical studies are registered atwww.clinicaltrials.govas NCT01539473 (tyramine interaction study conducted at Covance Clinical Research Center, Evansville, IN) and NCT01577459 (pseudoephedrine interaction study conducted at Vince and Associates Clinical Research, Overland Park, KS).

scholarly journals Effects of some antibiotics on glucose 6-phosphate dehydrogenase in sheep liver

2012 ◽  
Vol 47 (No. 10 - 11) ◽  
pp. 283-288 ◽  
Author(s):  
M. Çiftci ◽  
V. Turkoglu ◽  
S. Aldemir
Keyword(s):  
Gel Electrophoresis ◽  
Enzyme Purification ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sheep Liver ◽  
Sds Page ◽  
In Vitro Effects ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Sepharose 4B

In vitro effects of penicillin, sulbactam, cefazolin, and amikacine on the activity of the enzyme glucose-6-phosphate dehydrogenase in sheep liver were investigated. Glucose 6-phosphate dehydrogenase was purified from sheep liver, using a simple and rapid method. The purification consisted of two steps, preparation of homogenate and 2’, 5’-ADP Sepharose 4B affinity chromatography. As a result of the two consecutive procedures, the enzyme, having the specific activity of 11.76 EU/mg proteins, was purified with a yield of 35.72% and 1.913 fold. In order to control the enzyme purification SDS polyacrylamide gel electrophoresis (SDS-PAGE) was done. SDS-PAGE showed a single band for the enzyme. In addition, I50 values of the antibiotics were determined by plotting activity % vs. antibiotic concentrations. I50 values were 17.71 mM for penicillin, 27.38 mM for sulbactam, 28.88 mM for cefazolin, and 30.59 mM for amikacine.

scholarly journals Hepatic microsomal Ca2+-dependent ATPase. Calmodulin-dependence and partial purification

1983 ◽  
Vol 214 (1) ◽  
pp. 69-75 ◽  
Author(s):  
P B Moore ◽  
N Kraus-Friedmann
Keyword(s):  
Affinity Chromatography ◽  
Microsomal Fraction ◽  
Specific Activity ◽  
Fold Increase ◽  
Partial Purification ◽  
Dependent Atpase

The hepatic microsomal fraction contains tightly bound calmodulin as demonstrated by affinity chromatography. When this calmodulin was partially removed by EGTA treatment (0.5 mM-EGTA), the uptake of 45Ca2+ by the microsomal vesicles was stimulated by added calmodulin and inhibited by trifluoperazine (TFP). The Ca2+-dependent ATPase was partially purified on a calmodulin column. This partial purification resulted in a 500-fold increase in the specific activity of the enzyme when measured in the presence of added calmodulin. Antibodies prepared against calmodulin prevented this stimulatory effect. The fraction eluted from the calmodulin column contained several protein bands indicating that the specific activity of the Ca2+-dependent ATPase is probably still underestimated. There are likely to be other calmodulin-sensitive processes present in the hepatic microsomal fraction.

In vitro effects of toxaphene on mitochondrial calcium ATPase and calcium uptake in selected rat tissues

Life Sciences ◽  
1985 ◽  
Vol 36 (5) ◽  
pp. 427-433 ◽  
Author(s):  
C.H. Trottman ◽  
K.S. Prasada Rao ◽  
W. Morrow ◽  
J.E. Uzodinma ◽  
D. Desaiah
Keyword(s):  
Calcium Uptake ◽  
Calcium Atpase ◽  
Mitochondrial Calcium ◽  
Rat Tissues ◽  
In Vitro Effects

Ligustilide Reduces Phenylephrine Induced-Aortic Tension In Vitro but has No Effect on Systolic Pressure in Spontaneously Hypertensive Rats

2007 ◽  
Vol 35 (03) ◽  
pp. 487-496 ◽  
Author(s):  
Jun-Rong Du ◽  
Yan Yu ◽  
Yao Yao ◽  
Bo Bai ◽  
Xu Zong ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Essential Oil ◽  
Systolic Blood Pressure ◽  
Systolic Pressure ◽  
Reduce Blood Pressure ◽  
Shr Rats ◽  
Spontaneously Hypertensive ◽  
Long Time

Radix Angelica sinensis, known as Danggui in Chinese, has been used to treat cardiovascular diseases in traditional Chinese medicine for a long time. Experimental evidence showed that the essential oil of Danggui could reduce blood pressure in rabbits, cats or hypertensive dogs when given intravenously. In this study, we investigated the effects of Z-ligustilide, the main lipophilic component of the essential oil of Danggui on aortic tension induced by phenylephrine, an alpha-adrenergic agonist, in vitro and the systolic blood pressure in SHR rats. We demonstrated for the first time that ligustilide can significantly reduce the phenylephrine-induced aortic tension in vitro with IC50 about 64 μg/ml, but has no in vivo effect on systolic blood pressure in SHR rats when administrated orally. The data on transport of ligustilide across Caco-2 monolayer suggested an efficient intestinal absorption of ligustilide in vivo, implying that the non-effectiveness of ligustilide in vivo is not due to the poor absorption in the gastrointestinal tract. Further studies on whether ligustilide is one of the main anti-hypertensive components of the essential oil are needed.

In vitro Effects of Enamel Matrix Proteins on Rat Bone Marrow Cells and Gingival Fibroblasts

2004 ◽  
Vol 83 (2) ◽  
pp. 134-138 ◽  
Author(s):  
S. Keila ◽  
C.E. Nemcovsky ◽  
O. Moses ◽  
Z. Artzi ◽  
M. Weinreb
Keyword(s):  
Bone Marrow ◽  
Fold Increase ◽  
Matrix Proteins ◽  
Enamel Matrix ◽  
Gingival Fibroblasts ◽  
Enamel Matrix Proteins ◽  
Alp Activity ◽  
In Vitro Effects ◽  
Rat Bone

Emdogain® (EMD), a formulation of Enamel Matrix Proteins (EMP), is used clinically for periodontal regeneration, where it stimulates cementum formation and promotes gingival healing. In this study, we investigated the in vitro effects of EMD on rat bone marrow stromal cells (BMSC) and gingival fibroblasts (GF). EMD (at 25 μg/mL) increased the osteogenic capacity of bone marrow, as evidenced by ~ three-fold increase in BMSC cell number and ~ two-fold increase in alkaline phosphatase (ALP) activity and mineralized nodule formation. The presence of EMD in the initial stages (first 48 hrs) of the culture was crucial for this effect. In contrast, EMD did not induce osteoblastic differentiation of GF (evidenced by lack of mineralization or ALP activity) but increased up to two-fold both their number and the amount of matrix produced. These in vitro data on BMSC and GF could explain the promotive effect of EMD on bone formation and connective tissue regeneration, respectively.

scholarly journals Stimulation of cell proliferation in skeletal tissues of the rat by defined parathyroid hormone fragments

1991 ◽  
Vol 277 (3) ◽  
pp. 863-868 ◽  
Author(s):  
D Sömjen ◽  
K D Schlüter ◽  
E Wingender ◽  
H Mayer ◽  
A M Kaye
Keyword(s):  
Parathyroid Hormone ◽  
Bone Resorption ◽  
Thymidine Incorporation ◽  
Specific Activity ◽  
Fold Increase ◽  
Dependent Manner ◽  
Equimolar Concentration ◽  
Dose Dependent

We have found, in previous studies in vitro using skeletal derived cell cultures, that mid-region fragments of human parathyroid hormone (hPTH) stimulate [3H]thymidine incorporation into DNA and increase the specific activity of the brain-type isoenzyme of creatine kinase (CK). These changes occurred without an increase in cyclic AMP formation which is linked to bone resorption. In this study, we found that the mid-region fragment hPTH-(28-48) stimulated CK activity in diaphysis, epiphysis and kidney in a time- and dose-dependent manner, parallel to the effects of the whole molecule bovine (b)PTH-(1-84) and the fully active fragment hPTH-(1-34). The increase caused by hPTH-(28-48) at a dose of 1.25 micrograms/rat was not less than the 2-fold increase caused by a roughly equimolar concentration bPTH-(1-84). A significant increase was reached at 1 h after intraperitoneal injection in all cases. All three sequences of PTH caused an increase in [3H]thymidine incorporation into DNA in diaphysis and epiphysis, but not in kidney, 24 h after injection. A fragment further towards the C-terminal, hPTH-(34-47), was inactive compared with an equimolar concentration of the fragment hPTH-(25-39), which stimulated both CK activity and DNA synthesis. These results in vivo are in line with previous findings in vitro; they provide further support for the suggestion that mid-region fragments of the PTH molecule could be used to induce bone formation without incurring the deleterious effect of bone resorption.

Oral supplementation with glycine reduces oxidative stress in patients with metabolic syndrome, improving their systolic blood pressure

2013 ◽  
Vol 91 (10) ◽  
pp. 855-860 ◽  
Author(s):  
Margarita Díaz-Flores ◽  
Miguel Cruz ◽  
Genoveva Duran-Reyes ◽  
Catarina Munguia-Miranda ◽  
Hilda Loza-Rodríguez ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Metabolic Syndrome ◽  
Systolic Blood Pressure ◽  
Specific Activity ◽  
Thiobarbituric Acid ◽  
Treated Group ◽  
Contributing Factors ◽  
Oral Supplementation ◽  
Glucose 6 Phosphate Dehydrogenase

Reactive oxygen species derived from abdominal fat and uncontrolled glucose metabolism are contributing factors to both oxidative stress and the development of metabolic syndrome (MetS). This study was designed to evaluate the effects of daily administration of an oral glycine supplement on antioxidant enzymes and lipid peroxidation in MetS patients. The study included 60 volunteers: 30 individuals that were supplemented with glycine (15 g/day) and 30 that were given a placebo for 3 months. We analysed thiobarbituric acid reactive substances (TBARS) and S-nitrosohemoglobin (SNO-Hb) in plasma; the enzymatic activities of glucose-6-phosphate dehydrogenase (G6PD), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) in erythrocytes; and the expression of CAT, GPX, and SOD2 in leukocytes. Individuals treated with glycine showed a 25% decrease in TBARS compared with the placebo-treated group. Furthermore, there was a 20% reduction in SOD-specific activity in the glycine-treated group, which correlated with SOD2 expression. G6PD activity and SNO-Hb levels increased in the glycine-treated male group. Systolic blood pressure (SBP) also showed a significant decrease in the glycine-treated men (p = 0.043). Glycine plays an important role in balancing the redox reactions in the human body, thus protecting against oxidative damage in MetS patients.

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