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At least 973 records · Page 54Linked to original sources
PubMed1993

Safety of dextran in relation to other colloids--ten years experience with hapten inhibition.

OBJECTIVE: The effects of hapten inhibition with dextran 1 (molecular weight: 1,000 D, Promit), which is in use since 1982 for the prevention of severe dextran-induced anaphylactic reactions (DIAR) caused by immune complexes, were studied. DESIGN: Spontaneous reports to the manufacturer and to the WHO database INTDIS regarding adverse reactions to clinical dextran after preinjection of dextran 1 and to dextran 1 alone were collected from 1983 to 1992. During this period a total of 5.1 million doses of dextran 1 were sold in 15 countries. INTERVENTIONS: Analysis of pre- and post-reaction titers of dextran-reactive antibodies (DRA) was made in most Scandinavian reports. RESULTS: The incidence of severe DIAR (grades III-V) to clinical dextran after the prophylactic use of hapten inhibition was approximately 1/200,000 patients receiving dextran 1. In Sweden, where reporting of severe adverse drug reactions is mandatory, the incidence was approximately 1/70,000, indicating a 35-fold reduction. Only 2 fatal reactions were reported, an incidence of 1/2.5 million doses, indicating a 90-fold reduction. Both these occurred in patients with extremely high titers of DRA. Side effects to dextran 1, mostly mild, were reported in approximately 1 case per 100,000 doses. These side effects were not antibody mediated. CONCLUSIONS: The above findings, together with other recent safety profile data, suggest that dextran with hapten inhibition has possibly become the safest plasma substitute in current clinical practice.

Adverse Drug Reaction Reporting Systems↗
PubMed1994

CMDBS, functional analogue of heparin sulfate as a new class of corneal ulcer healing agents.

Soluble dextran polymer derivatives (CMDBSs) are originally synthesized as heparin-like plasma substitutes. Some of them mimic heparin in its interactions and stabilize, protect and facilitate actions of heparin binding growth factors. The wound healing activity of one specific CMDBS was studied in a model of corneal ulcer on the rabbit eye and compared with the activity of basic fibroblast growth factors (bFGF) added alone or in association with CMDBS. Total reepithelization was observed with bFGF + CMDBS, bFGF alone and CMDBS alone after, respectively, 3.8 +/- 0.78, 4.3 +/- 0.67 and 4.4 +/- 0.51 days. All treatments were efficient if compared with eyes treated with saline (p < 0.0001). The grade of significance of the applied treatments was as follows: bFGF + CMDBS > bFGF > CMDBS > saline. Our study pinpoints that some specific CMDBS are as potent agents as bFGF for corneal ulcer healing, and can therefore be proposed for therapeutic use.

Animals↗
PubMed1987

Identification of Na+,K+-ATPase inhibitors of volume-expanded hog plasma.

Na+,K+-adenosine triphosphatase (ATPase) inhibitors possessing inhibitory activities against the specific binding of ouabain to Na+,K+-ATPase and 86Rb uptake into hog erythrocytes have been purified from the plasma of hog acutely infused with saline. The purifications were performed by a combination of Amberlite XAD-2 adsorption chromatography and several steps of high performance liquid chromatography using four different types of columns. Inhibitors purified to homogeneity were identified as linoleic and oleic acids, gamma-stearoyllysophosphatidylcholine, gamma-arachidoyllysophosphatidylcholine, gamma-linoleoyllysophosphatidylcholine, and gamma-oleoyllysophosphatidylcholine. Small amounts of beta-arachidoyllysophosphatidylcholine, gamma-docosapentaenoyllysophosphatidylcholine, gamma-eicosatrienoyllysophosphatidylcholine, and gamma-palmitoyllysophosphatidylcholine were also detected by both fast atom bombardment mass and proton nuclear magnetic resonance spectrometric studies. Only gamma-acyllysophosphatidylcholines showed inhibitory activities on Na+,K+-ATPase and ouabain-binding activities. These lysophosphatidylcholines and unsaturated free fatty acids were effective at 100 microM levels in attaining 50% inhibition of the enzyme activity. The ouabain-displacing activity in plasma caused by these compounds increased with time during saline infusion. The maximal plasma levels of these components were approximately 10 times higher than that in the preinfusion plasma sample.

Animals↗
PubMedDate not supplied

Increased vascular sensitivity to angiotensin ii in psychosocial hypertensive mice.

CBA mice develop hypertension when placed in complex population cages that facilitate social interactions and competition for territory. After 1 month, these mice have normal plasma renin levels, but blockade of converting enzyme lowers blood pressure to normal. To test the possibility that this normal-renin hypertension is caused by enhanced pressor responsiveness to angiotensin II (AII), we examined the effects of AII on hindquarter and renal vasculatures from 13 hypertensive and 13 normotensive mice. Both vascular beds were pump-perfused at a constant flow with plasma substitute. Optimal perfusion flows and basal pressures were similar in hindquarter (8 ml/100 g/min; 60 mm Hg) and renal vasculatures (130 ml/100 g/min; 50 mm Hg) from normotensive and hypertensive mice. Threshold constrictor responses to AII were elicited at a significantly lower dose in both vasculatures of hypertensive mice than in those of normotensive mice. Maximal pressor responses to AII were greater in the hindquarters of hypertensive mice than in those of normotensive mice, but were not different in the renal vasculatures of the two groups. Vasoconstrictor sensitivity to norepinephrine was also increased in the hindquarters of hypertensive mice; however, the changes in threshold and maximal pressor response were less than for AII. Responsiveness to norepinephrine in the renal vasculatures of hypertensive mice was not different from that in the kidneys of normotensive mice. We conclude that the hyperresponsiveness to AII in the resistance vessels plays an important role in maintaining elevated blood pressure in this psychosocial model of hypertension.

Angiotensin II↗
PubMed1987

Increased vasodilator responses to acetylcholine in psychosocial hypertensive mice.

Responsiveness to endothelium-dependent (acetylcholine and A23187) and endothelium-independent (nitroprusside and 8-bromo cyclic guanosine 3',5'-monophosphate [cGMP]) vasodilators was examined in two vascular preparations from hypertensive and normotensive mice. CBA Agouti mice were made hypertensive by exposure to social stress in a complex population cage. After 2 months, the hindquarter vascular bed was pump-perfused at a constant flow with plasma substitute to evaluate changes in perfusion pressure, and helical strips of aorta were suspended in muscle baths for measurement of isometric force generation. Tissues were treated with methoxamine to induce contractile tone. Threshold dilator responses to acetylcholine were elicited at a significantly lower dose in the hindquarters of hypertensive mice than in those from normotensive mice, indicating increased vasodilator sensitivity. In contrast, vasodilator responsiveness to nitroprusside in hindquarters of hypertensive mice did not differ from that in hindquarters of normotensive mice. Aortas from hypertensive mice were more sensitive (lower ED50) to the relaxant effects of acetylcholine and A23187 than those from normotensive mice. The relaxant effects of nitroprusside and 8-bromo cGMP on aortas from hypertensive mice were not significantly different from those in normotensive aortas. Aortic strips that had been rubbed on the lumen surface with a wooden stick did not relax to acetylcholine or A23187. In aortas that were not initially contracted with methoxamine, acetylcholine and A23187 caused small contractions from baseline. The magnitude of these contractile responses were potentiated after removal of the endothelium, and the potentiation was greater in aortas from hypertensive mice. These results demonstrate an increased responsiveness to endothelium-dependent vasodilators in this psychosocial model of hypertension.

Acetylcholine↗
PubMed1989

Effect of fludrocortisone acetate in patients with subarachnoid hemorrhage.

In this study with randomized controls, we administered fludrocortisone acetate to 46 of 91 patients with subarachnoid hemorrhage in an attempt to prevent excessive natriuresis and plasma volume depletion. Fludrocortisone significantly reduced the frequency of a negative sodium balance during the first 6 days (from 63% to 38%, p = 0.041). A negative sodium balance was significantly correlated with decreased plasma volume during both the first 6 days (p = 0.014) and during the entire 12-day study period (p = 0.004). Although fludrocortisone treatment tended to diminish the decrease in plasma volume, the difference was not significant (p = 0.188). More patients in the control group developed cerebral ischemia (31% vs. 22%) and, consequently, more control patients were treated with plasma volume expanders (24% vs. 15%), which may have masked the effects of fludrocortisone on plasma volume. Fludrocortisone therefore reduces natriuresis and remains of possible therapeutic benefit in the prevention of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

Clinical Trials as Topic↗
PubMed1992

Hypertension with hemodilution prevents multifocal cerebral hypoperfusion after cardiac arrest in dogs.

BACKGROUND: Improved neurological outcome with postarrest hypertensive hemodilution in an earlier study could be the result of more homogeneous cerebral perfusion and improved O2 delivery. We explored global, regional, and local cerebral blood flow by stable xenon-enhanced computed tomography and global cerebral metabolism in our dog cardiac arrest model. METHODS: Ventricular fibrillation cardiac arrest of 12.5 minutes was reversed by brief cardiopulmonary bypass, followed by life support to 4 hours postarrest. We compared control group I (n = 5; mean arterial blood pressure, 100 mm Hg; hematocrit, greater than or equal to 35%) with immediately postarrest reflow-promoted group II (n = 5; mean arterial blood pressure, 140-110 mm Hg; hypervolemic hemodilution with plasma substitute to hematocrit, 20-25%). RESULTS: After initial hyperemia in both groups, during the "delayed hypoperfusion phase" at 1-4 hours postarrest, global cerebral blood flow was 51-60% of baseline in group I versus 85-100% of baseline in group II (p less than 0.01). Percentages of brain tissue voxels with no flow, trickle flow, or low flow were lower (p less than 0.01) and mean regional cerebral blood flow values were higher in group II (p less than 0.01). Global cerebral oxygen uptake recovered to near baseline values at 3-4 hours postarrest in both groups. Postarrest arterial O2 content, however, in hemodiluted group II was 40-50% of that in group I. Thus, the O2 uptake/delivery ratio was increased (worsened) in both groups at 2-4 hours postarrest. CONCLUSIONS: After prolonged cardiac arrest, immediately induced moderate hypertensive hemodilution to hematocrit 20-25% can normalize cerebral blood flow patterns (improve homogeneity of cerebral perfusion), but does not improve cerebral O2 delivery, since the flow benefit is offset by decreased arterial O2 content. Individualized titration of hematocrit or hemodilution with acellular O2 carrying blood substitute (stroma-free hemoglobin or fluorocarbon solution) would be required to improve O2 uptake/delivery ratio.

Animals↗
PubMed1974

Proximal tubule reabsorption after hyperoncotic albumin infusion. Role of parathyroid hormone and dissociation from plasma volume.

Preferential expansion of the plasma volume by infusion of salt-poor hyperoncotic albumin solution decreases sodium reabsorption by the proximal tubule. The present micropuncture studies test the thesis that albumin infusion depresses proximal reabsorption by an effect unrelated to expansion of the plasma volume, perhaps due to an effect of parathyroid hormone (PTH) on proximal sodium reabsorption. Infusion of salt-poor hyperoncotic albumin significantly decreased plasma ionized calcium, increased immunoreactive PTH (iPTH) in plasma, decreased sodium reabsorption by the proximal tubule, and increased phosphate clearance. In contrast, infusions of albumin, in which the ionized calcium was restored to normal plasma levels, had no significant effect on ionized calcium, iPTH, proximal reabsorption, or phosphate clearance in intact dogs. Similarly, in parathyroidectomized animals given a constant replacement infusion of PTH, albumin infusion had no significant effect on proximal reabsorption or phosphate clearance. Plasma volume was markedly expanded following albumin infusion in all groups of dogs. These findings (a) indicate that PTH plays a significant role in the decrease in sodium reabsorption by the renal proximal tubule after salt-poor hyperoncotic albumin infusion, and (b) dissociate preferential expansion of the plasma volume from decreases in sodium reabsorption by the proximal tubule.

Absorption↗