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PubMed2004

Histone H1 and the origin of protamines.

We present evidence that chordate protamines have evolved from histone H1. During the final stages of spermatogenesis, the compaction of DNA in many organisms is accomplished by the replacement of histones with a class of arginine-rich proteins called protamines. In other organisms, however, condensation of sperm DNA can occur with comparable efficiency in the presence of somatic-type histones or, alternatively, an intermediate class of proteins called protamine-like proteins. The idea that the highly specialized sperm chromosomal proteins (protamines) and somatic chromosomal proteins (histones) could be related dates back almost to the discovery of these proteins. Although this notion has frequently been revisited since that time, there has been a complete lack of supporting experimental evidence. Here we show that the emergence of protamines in chordates occurred very quickly, as a result of the conversion of a lysine-rich histone H1 to an arginine-rich protamine. We have characterized the sperm nuclear basic proteins of the tunicate Styela montereyensis, which we show consists of both a protamine and a sperm-specific histone H1 with a protamine tail. Comparison of the genes encoding these proteins to that of a sister protochordate, Ciona intestinalis, has indicated this rapid and dramatic change is most likely the result of frameshift mutations in the tail of the sperm-specific histone H1. By establishing an evolutionary link between the chromatin-condensing histone H1s of somatic tissues and the chromatin-condensing proteins of the sperm, these results provide unequivocal support to the notion that vertebrate protamines evolved from histones.

Amino Acid Sequence↗
PubMed1996

Paracellular transport of water and carbohydrates during intestinal perfusion of protamine in the rat.

With these experiments, the authors' purpose was to determine whether the intestinal perfusion of protamine would successfully block paracellular transport without causing significant change in cardiovascular function. In anesthetized (50 mg x kg-1 sodium pentobarbital) rats (n=12), heart rate and mean arterial blood pressure were measured during perfusion (0.5 mL x min-1) of a carbohydrate-electrolyte solution through the small intestine. The carbohydrate-electrolyte solution contained 150 mM glucose, 150 mM fructose, 10 mM lactulose, 17 mEq sodium, 3 mEq potassium, and either 0.0, 0.1, 1.0, or 10 mg x mL-1 protamine. Osmolality of the 4 solutions ranged from 363 +/- 2 to 365 +/- 3 mOsm x kg-1. Core temperature was maintained at 37 degrees C in an environmental chamber. Heart rate and mean arterial blood pressure were constant during all intestinal perfusions. Forty-one percent of the perfused lactulose was absorbed. Absorption of glucose, fructose, and lactulose was significantly inhibited by 0.1 mg x mL-1 protamine, while water absorption was decreased 41 percent by 1.0 mg x mL-1 protamine. Water and lactulose absorption fell 75% with protamine, and glucose and fructose absorption fell 50%. Lactulose and fructose absorption did not decrease further when protamine dose rose to 10 mg x mL-1. These results indicate that 1) perfusion of protamine into the small intestine in doses that significantly affect intestinal transport does not significantly affect heart rate and mean arterial blood pressure; and 2) if the primary effect of protamine is to block paracellular movement of water and solute, the greater protamine inhibition of water and lactulose absorption is consistent with a greater paracellular transport of water and lactulose than for glucose and fructose.

Animals↗
PubMed1999

The direct effects of heparin and protamine on canine tracheal smooth muscle tone.

UNLABELLED: Heparin and protamine are used for cardiopulmonary bypass in cardiac surgery; however, the direct effects and mechanisms of these drugs on airway smooth muscle tone are still not fully known. We investigated the in vitro effects of these drugs on canine tracheal smooth muscle by measuring the muscle tension and intracellular Ca2+ concentration ([Ca2+]i) and by measuring inward Ca2+ currents (I(Ca)) through voltage-dependent Ca2+ channels. [Ca2+]i was monitored by the 500-nm light emission ratio of preloaded Ca2+ indicator fura-2. Isometric tension was measured simultaneously. Whole-cell patch clamp recording techniques were used to investigate the effects of the drugs on I(Ca) in freshly dispersed smooth muscle cells. Heparin (0.12-120 U/mL), protamine (0.15-150 U/mL), or heparin-protamine complex (4:5 U/U) was introduced into a bath solution. Protamine and heparin-protamine complex dose-dependently inhibited both carbachol-induced contraction of the muscle and increase in [Ca2+]i. These drugs also decreased the I(Ca) of the muscle cells and shifted the inactivation curve to a more negative potential. Heparin itself had a slight enhancing effect on carbachol-induced muscle contraction without changing [Ca2+]i. Protamine and heparin-protamine complex can decrease the agonist-induced increase in [Ca2+]i by the inhibition of voltage-dependent Ca2+ channels both in the activated and inactivated states. IMPLICATIONS: Protamine and heparin-protamine complex inhibited carbachol-induced canine tracheal smooth muscle contraction by inhibiting the increase in intracellular concentration of free Ca2+. These drugs can decrease the agonist-induced increase in intracellular Ca2+ by the inhibition of voltage-dependent Ca2+ channels in both the activated and inactivated states.

Animals↗
PubMed1990

Impaired myocardial function and oxygen utilization due to protamine sulfate in an isolated rabbit heart preparation.

The myocardial effects of protamine, with and without heparin, were documented in this investigation. Isolated rabbit hearts (n = 30) were retrograde perfused with Krebs-Ringers bicarbonate solution aerated with 95% O2/5% CO2 through the aortic root (37 C, 80 mmHg). Developed left ventricular blood pressure, heart rate, coronary artery flow, contractility as reflected by peak +dp/dt, oxygen extraction (a-vO2), and oxygen consumption (VO2) were measured at baseline and continuously throughout the experiment. Protamine (25 micrograms, 50 micrograms, and 250 micrograms per mL of perfusate) was circulated in the Krebs-Ringers buffer to hearts perfused without heparin (groups I, II, and III) or hearts perfused with heparin added to the buffer solution, 0.1 IU/1.0 microgram protamine (groups IV, V, and VI). Blood pressure 4 minutes after protamine was less in groups III (-23 mmHg) and VI (-28 mmHg) than in groups I (-6 mmHg), II (-18 mmHg), IV (-1 mmHg), and V (-7 mmHg). Heart rate changes (beats/minute) at 4 minutes revealed similar dose-dependent reductions (III and VI: -51, -55; II and V: -36, -36; and I and IV: -20, -16, respectively). Coronary artery flow at 4 minutes was slightly increased in groups III (9 mL/minute) and VI (15 mL/minute), but was relatively unchanged in the other groups. Decreases in contractility were apparent in all groups 4 minutes after protamine was started: group I, -14%; II, -16%; III, -30%; IV, -7%; V, -15%; and VI, -34%. Similarly declines in oxygen extraction and consumption were noted in all groups at the same time period and were greater in groups III (-53%, -44%) and VI (-55%, -49%) than in groups I (-25%, -26%), II (-15%, -12%), IV (-48%, -49%) and V (-15%, -18%), with p less than or equal to 0.05 or p less than or equal to 0.01 compared to baseline. Three of ten hearts exposed to high-dose protamine stopped beating after 5 minutes. This investigation establishes, for the first time, that protamine has dose- and time-specific adverse effects on cardiac contractility. In addition protamine decreases myocardial a-vO2 and VO2. These changes may contribute to certain adverse events accompanying the clinical administration of protamine.

Animals↗
PubMed1987

Human platelet factor 4 and protamine sulphate interaction with glycosaminoglycans in the rabbit.

We studied the action of protamine sulphate on human platelet factor 4 (PF4) kinetics in rabbits in the presence of various glycosaminoglycans (CAGs). The animals pretreated with heparin showed high initial PF4 levels with a subsequent slow monoexponential clearance. The PF4 kinetics, in the presence of heparan and dermatan sulphate, reflected the different affinities that PF4 has for these GAGs. Protamine, at dosages that totally neutralized 1000 USP units of heparin pretreatment, caused an immediate disappearance in the circulating PF4. However, a second heparin injection 10 min after protamine, induced a PF4 peak release. It is possible that protamine displaced the PF4 from the binding sites of heparin, releasing it for storage in the body 'pool', from where it can be harvested again. The action of protamine on PF4 kinetics in the rabbits pretreated with 30 mg heparan sulphate was similar to that obtained with heparin pretreatment; however, a higher dose of protamine was required to obtain the optimal effect. After a 20 mg dose of protamine, unexpectedly, a bolus of heparin did not produce any peak release of PF4 in the rabbits pretreated with 30 mg of dermatan sulphate. Although part of the protamine will displace PF4 from the binding sites of the dermatan sulphate molecule, the remaining part of protamine could probably be bound to this GAG without losing its activity so that, upon subsequent heparin injection, it is immediately neutralized, rendering it unavailable for further PF4 harvesting.

Animals↗
PubMed1987

Rapid purification of protein kinase C from rat brain. A novel method employing protamine-agarose affinity column chromatography.

We describe a rapid purification of protein kinase C from rat brain cytosol employing a specific substrate, protamine-coupled to agarose. Sequential chromatography on DEAE-Sephacel, phenyl-Sepharose CL-4B, and protamine-agarose columns resulted in a 1,500-fold purification of protein kinase C. SDS-PAGE analysis of the purified enzyme resolved a doublet protein of 77-80 kDa. This doublet was recognized by a polyclonal antiserum against protein kinase C. Proteolytic digestion of each protein band generated similar peptide fragments. The underlying principle of the protamine sulfate purification method was also clarified. Protamine can serve as a Ca2+/phospholipid-independent substrate. We demonstrate phosphorylation of protamine on the column; phosphorylated protamine did not bind the enzyme with the same affinity and this covalent modification was most probably responsible for releasing the bound enzyme from the column after addition of Mg2+ and ATP. The C kinase inhibitor, H7, inhibits protamine phosphorylation in a dose-dependent fashion but does not prevent binding of the enzyme to a protamine-agarose column. We therefore conclude that protamine interacts with the active center of the enzyme enabling it to be phosphorylated, upon which it loses its binding affinity for C kinase.

Animals↗
PubMedDate not supplied

On the expression of protamine genes in the testis of man and other mammals.

Protamines are low molecular weight, highly basic nuclear proteins involved in the condensation of sperm chromatin. cDNA clones for human protamine 1 and 2 (PRM1 and PRM2) were used for Northern blot experiments with RNA from different human tissues. Protamine transcripts, 0.6 kb and 0.9 kb in lengths for PRM1 and PRM2, respectively, were detected only in testicular RNA. The hybridization signals though did not produce sharp bands but enclosed a minor fraction of significant smaller transcripts. When polysomal RNA fractions were used in the hybridization, these shorter transcripts, 0.45 kb in length for PRM1 and 0.7 kb for PRM2, were specifically enriched. As demonstrated by in situ hybridization on human testis sections, the transcripts of both protamine genes are restricted to the central cell layer of the tubuli seminiferi corresponding to the spatial arrangement of postmeiotic cells. This result indicates that the protamine genes in the human are postmeiotically and haploid expressed. When cDNA clones of both protamines of the boar (BPrm-1 and BPrm-2) were used for hybridization experiments with the testicular RNA of those mammalian species which lack protamine 2 in their spermatozoa, the presence of transcripts for both protamines was detected. It can be assumed that mammals in general are endowed with at least two protamine genes which are both transcribed but are translationally regulated in a species-specific manner.

Animals↗
PubMed1989

Influence of platelet factor 4 on the neutralization of heparin by protamine.

In vitro, PF4 is comparable to protamine sulfate in the neutralization of heparin, but the complexes formed with heparin are different. Even with an excess of PF4, no large PF4-heparin complexes are formed and none of the complexes are able to activate ATIII, nor do these complexes dissociate on incubation in plasma at 37 degrees C. The action of PF4 and protamine is complementary. However, excess protamine displaces PF4 or prevents its complexing with heparin. When excess protamine is used to neutralize heparin in the presence of PF4, large heparin-protamine complexes are formed incorporating PF4. In contrast to the heparin-protamine complexes formed without PF4, these do not activate ATIII nor do they dissociate on incubation. Since PF4 is liberated during ECB procedures, its contribution to the stability of heparin-protamine complexes in vivo may influence the amount of protamine needed to neutralize heparin as well as affect the reactions which have been reported on injection of protamine after ECB.

Animals↗
PubMed1995

Effects of ciprofloxacin and protamine sulfate combinations against catheter-associated Pseudomonas aeruginosa biofilms.

Infection is a common complication associated with the use of transcutaneous and implanted medical devices. These infections are generally difficult to treat and frequently require removal of the biomaterial before the infection can be completely eradicated. The presence of a bacterial biofilm recalcitrant to treatment often mediates these infections. We studied the influence of a polycationic protein, protamine sulfate, on the efficacy of the fluoroquinolone ciprofloxacin against a clinical isolate of Pseudomonas aeruginosa. A P. aeruginosa biofilm was developed on 1-cm sections of red rubber catheter material and then treated with various combinations of protamine sulfate and ciprofloxacin. The present work demonstrated that ciprofloxacin in combination with protamine was more effective against biofilms than was ciprofloxacin alone. Protamine sulfate at 50 micrograms/ml combined with antibiotic at 0.5 microgram/ml reduced the number of viable cells by an average of 98.97%, while protamine sulfate at 50 micrograms/ml alone resulted in an average 107.8% increase and antibiotic alone resulted in an average 58.6% reduction after 24 h. Furthermore, protamine sulfate, in combination with ciprofloxacin, inhibited P. aeruginosa in a dose-dependent fashion. It was further observed that treatment with the combination of protamine sulfate and ciprofloxacin had a more drastic effect on planktonic organisms as compared with the P. aeruginosa biofilms; the MBC was reduced to < 0.05 microgram/ml in the presence of 25 micrograms of protamine sulfate per ml. These findings were substantiated by ultrastructure studies of treated cells using scanning and transmission electron microscopy. The synergism between ciprofloxacin and protamine sulfate significantly enhanced the efficacy of ciprofloxacin against planktonic and biofilm P. aeruginosa.

Anti-Bacterial Agents↗
PubMed1987

Protamine alters apical membrane K+ and Cl- permeability in gallbladder epithelium.

Protamine addition to the solution bathing the mucosal side of Necturus gallbladder epithelium (25-100 mg/l) caused depolarization of both cell membranes, a mucosa-negative change in transepithelial voltage, an increase in the apical membrane resistance (Ra) followed by a decrease, and a monotonic increase in transepithelial resistance (Rt). In protamine (25 mg/l), the change in apical membrane voltage elicited by elevating mucosal solution [K+] from 2.5 to 92.5 mM was reduced from 66 +/-2 to 38 +/- 5 mV (P less than 0.001). The K+-induced fall in Ra was also reduced in protamine. These effects could also be elicited by elevating mucosal solution [K+] simultaneously with the addition of protamine and by transient addition of protamine during exposure to the high K+ medium. The effect of protamine on the electrodiffusive Cl- permeability of the apical membrane (PCl) was studied both in control and forskolin-treated tissues. In the absence of forskolin, the hyperpolarization of Vmc produced by lowering mucosal [Cl-] to 10 mM was reversed to a small depolarization; in forskolin, the initial depolarization produced by lowering [Cl-] was significantly increased. Finally, exposure to protamine in the absence of forskolin produced an initial fall in intracellular Cl- activity. Our results indicate that protamine decreases apical membrane K+ permeability and increases apical membrane PCl. The time course of the effects of protamine suggests the possibility of an initial effect on surface potential, followed by secondary actions mediated by intracellular events.

Animals↗
PubMed1992

Protamine releases endothelium-derived relaxing factor from systemic arteries. A possible mechanism of hypotension during heparin neutralization.

BACKGROUND: When used to reverse the anticoagulant effect of heparin, protamine sulfate often causes vasodilation that can lead to systemic hypotension. Protamine is rich in the basic amino acid arginine, which is the precursor of endothelial cell synthesis of nitric oxide, and nitric oxide is the active component of endothelium-derived relaxing factor (EDRF). METHODS AND RESULTS: To determine whether the hypotensive effect of protamine could be due to stimulated release of EDRF, we studied rings (4-5 mm) of canine coronary, femoral, and renal artery suspended in organ chambers containing physiological salt solution (37 degrees C and 95% O2-5% CO2). Arterial rings with and without endothelium were contracted with prostaglandin F2 alpha (2 x 10(-6) M) and exposed to increasing concentrations of protamine (final organ bath concentration, 40-400 micrograms/ml). In arterial segments without endothelium, protamine caused only a modest decrease in tension. However, protamine induced concentration-dependent relaxation in all arterial segments with endothelium, which was significantly greater than in segments without endothelium (p less than 0.05). The endothelium-dependent relaxation induced by protamine was inhibited by NG-monomethyl-L-arginine (L-NMMA) (10(-5) M), but L-NMMA had no effect on rings without endothelium. The action of L-NMMA could be reversed by L-arginine (10(-4) M) but not D-arginine (10(-4) M). CONCLUSIONS: This study demonstrates that protamine stimulates the release of EDRF from arterial endothelium, and that endothelium-dependent vasodilation may be an important cause of systemic hypotension during protamine infusion.

Animals↗
PubMed1993

[Stabilization of ascorbic acid aqueous solution by protamine].

Protamine was found to stabilize ascorbic acid (AsA) in aqueous solution. The concentration of AsA (50 mumol/l) dissolved in 0.05 M phosphate buffer, pH 7, decreased by 57% after standing for 90 min at 30 degrees C, whereas 91% of AsA remained under the same conditions in the presence of 60 mumol/l protamine. When 0.5 mumol/l of copper ion (II) was added to the above AsA solution (0.05 M phosphate buffer, pH 7) in the absence of protamine, AsA decreased by 5% after standing for 15 min at 30 degrees C. On the other hand, 91% of AsA remained after 15 min and 52% of AsA remained after 90 min under the same conditions in the presence of 60 mumol/l protamine. Furthermore, the effect of protamine on the stability of AsA in various pH solutions (pH 1-10) was examined after standing for 90 min at 30 degrees C. Degradation of AsA was accelerated by increasing the pH from 1 to 10. On the other hand, the effect of protamine (60 mumol/l) on the stabilization of AsA was recognizable above pH 5 and degradation of AsA was controlled at higher pH. When 0.5 mumol/l of copper ion (II) was added to the above solutions in the absence of protamine, degradation of AsA was greatly accelerated above pH 5. When 60 mumol/l of protamine was added to the solutions, the effect of protamine on the stabilization of AsA was observed above pH 5 and degradation of AsA was controlled at higher pH.

Ascorbic Acid↗
PubMedDate not supplied

DNA integrity is compromised in protamine-deficient human sperm.

The objective of this study was to examine the relationship between DNA integrity and protamines in human sperm. One hundred forty-nine male infertility patients were included in an Institutional Review Board-approved study. Sperm were evaluated for DNA fragmentation using the DNA Integrity Assay, a test equivalent to the sperm chromatin structure assay (SCSA). Additionally, nuclear proteins were extracted and the protamine-1/protamine-2 ratio (P1/P2), protamine-1 (P1), protamine-2 (P2), and total protamine concentrations were evaluated. We identified 37 patients with abnormally low P1/P2 ratios, 99 patients with normal P1/P2 ratios, and 13 patients with abnormally high P1/P2 ratios. DNA fragmentation was significantly elevated in patients with low P1/P2 ratios (37.1 +/- 6.02) vs those with normal and high P1/P2 ratios (26.7 +/- 1.9 and 23.8 +/- 3.2, respectively; P < .05) and was inversely correlated with the P1/P2 ratio (R(s) -0.18, P < .05), P1 concentration (R(s) -0.29, P < .001), P2 concentration (R(s) - 0.24, P < .005), and total protamine concentration (R(s) -0.28, P < .001). Furthermore, chi2 analysis revealed a significant increase in the incidence of marked DNA fragmentation in patients with diminished levels of either P1 or P2. The present study is the first to report that human sperm protamine content is significantly related to DNA fragmentation. In particular, sperm P1 and P2 concentrations inversely correlate with DNA fragmentation, indicating a protective role of the protamines against sperm DNA damage. In light of recent studies highlighting the negative effect of sperm DNA damage on ART outcomes, these findings indicate a possible clinical significance for human sperm protamine levels.

DNA Fragmentation↗
PubMed1988

The effect of protamine sulfate on platelet function.

The adverse effects of protamine sulfate, used to neutralize the anticoagulant action of heparin, include systemic hypotension, pulmonary artery hypertension, thrombocytopenia and leukopenia. For further evaluation of protamine's mechanism of action, a three-part investigation was performed. In part I platelet-rich plasma (PRP) was prepared from canine blood samples (n = 6) taken before and 2 minutes after injection of protamine. In part II human PRP (n = 5) was preincubated with protamine or distilled water. Adenosine diphosphate-induced aggregation of protamine-treated platelets was unchanged, but thrombin-induced aggregation was inhibited in both canine and human preparations (p less than 0.05). In part III thrombocytopenia was produced in splenectomized dogs (n = 5), using microporous filters, to 4.5-8.4% of the initial platelet count. Protamine reversal of the heparinization caused hypotension (maximally -29 mmHg 90 s after protamine), but not pulmonary arterial hypertension. Leukopenia developed before additional thrombocytopenia appeared. Protamine-platelet interaction inhibits thrombin-induced platelet aggregation. Platelets may play an important role in the pulmonary pressure rise during protamine reversal, but do not mediate the systemic hypotension.

Animals↗
PubMed2000

Protamine sulphate inhibits platelet membrane glycoprotein Ib-von Willebrand factor activity.

Platelet adhesion to the injured vessel wall is essential in haemostasis and thrombosis. This process involves the interaction of the platelet glycoprotein Ib (GPIb) with surface bound von Willebrand factor (vWF). Since synthetic polycationic peptides of the general formula (Arg)n, (Lys)n or (Arg-Lys)n inhibit GPIb-vWF interaction, they were suggested as potential antithrombotics. Protamine sulphate is a highly cationic polypeptide, arginine accounting for approximately 60% of the primary sequence, utilized to neutralize the anticoagulant effect of heparin after cardiac surgery. We have investigated potential effects of protamine sulphate on the function of GPIb-vWF. Addition of protamine sulphate to platelet-rich plasma (PRP), reduced significantly the GPIb-vWF activity as assessed by ristocetin-induced platelet agglutination. When protamine sulphate was added to PRP containing heparin, even at clinically relevant neutralizing doses the GPIb-vWF activity was reduced by 20-30% (p < 0.001). Protamine sulphate in excess of heparin nearly abolished the activity. Furthermore, the direct effect of protamine sulphate on collagen-induced platelet thrombus formation in non-anticoagulated human blood was investigated by employing an ex-vivo parallel-plate perfusion chamber device. Protamine sulphate (200 microg/mL) reduced platelet-collagen adhesion at shear rates of 650 and 2600 sec(-1) by 40% (p< 0.004) and 45% (p < 0.0001), respectively. The corresponding platelet thrombus volumes were concomitantly reduced by 90% (p < 0.006) and 84% (p < 0.05). Our data are questioning the rationale for empirical repetitive protamine sulphate administration when so-called "heparin rebound" after cardiac surgery is suspected, since protamine sulphate in excess of heparin may impair the platelet GPIb-vWF interaction necessary for normal haemostasis.

Anticoagulants↗
PubMed2000

Heparin-protamine complexes and C-reactive protein induce activation of the classical complement pathway: studies in patients undergoing cardiac surgery and in vitro.

The administration of protamine to patients undergoing cardiopulmonary bypass (CPB) to neutralize heparin and to reduce the risk of bleeding, induces activation of the classical complement pathway mainly by heparin-protamine complexes. We investigated whether C-reactive protein (CRP) contributes to protamine-induced complement activation. In 24 patients during myocardial revascularization, we measured complement, CRP, and complement-CRP complexes, reflecting CRP-mediated complement activation in vivo. We also incubated plasma from healthy volunteers and patients with heparin and protamine in vitro to study CRP-mediated complement activation. During CPB, CRP levels remained unchanged while C3 activation products increased. C4 activation occurred after protamine administration. CRP-complement complexes increased at the end of CPB and upon protamine administration. Incubation of plasma with heparin and protamine in vitro generated complement-CRP complexes, which was blocked by phosphorylcholine and stimulated by exogenous CRP. C4d-CRP complex formation after protamine administration correlated clinically with the incidence of postoperative arrhythmia. Protamine administration during cardiac surgery induces complement activation which in part is CRP-dependent, and correlates with postoperative arrhythmia.

Analysis of Variance↗
PubMedDate not supplied

Administration of clemastine--H1 histamine receptor blocker in the prevention of haemodynamic disorders after protamine sulfate administration in patients subjected to coronary artery bypass grafting in extracorporeal circulation.

INTRODUCTION: Adverse effects of protamine administration after CPB: fall in arterial blood pressure and pulmonary hypertension are still a source of problems. CPB and protamine administration are both accompanied by increased histamine levels in blood. The aim of this study was to examine if clemastine can accelerate the normalisation of arterial blood pressure during the protamine administration after CPB during CABG operations. MATERIAL AND METHODS: Fifty three patients subjected to CABG operations were studied. Control group (n = 27) did not receive clemastine, Clemastine group (n = 26) received 2 mg i.v. clemastine, before CPB. After CPB were completed, patients were given protamine (heparin to protamine ratio--1:1.5) within 7 minutes, through peripheral vein. Changes in arterial blood pressure from the beginning of protamine administration to 2.5, 5, 7.5, 10, 15, and 30 minutes thereafter, as well as heart rate, CVP, doses of inotropic drugs and vasodilators were compared between the groups. RESULTS: No difference in heart rate, CVP, doses of inotropic drugs and vasodilators between the group was noted. An increase in arterial blood pressure 5, 7.5, 10, and 15 minutes after the beginning of the protamine administration were greater in clemastine group than in control group. Groups were comparable with regard to surgical procedures and doses of anaesthetic drugs. It is now known that protamine exerts a negative effect on cardiac contractility either through a decrease in coronary perfusion pressure (vasodilatation), or through a direct toxic effect on cardiac muscle. The administration of clemastine before CPB can reduce peripheral vasodilatation and capillary leak related to histamine release during CPB. In the clemastine group, faster increase in arterial blood pressure toward a physiologic range was observed. We conclude that administration of clemastine is connected with the normalization of ABP during and after protamine reversal of heparin coagulation during CABG operations.

Blood Pressure↗
PubMed2003

Human protamines and the developing spermatid: their structure, function, expression and relationship with male infertility.

During spermiogenesis, the protamine proteins play an integral role in spermatid chromatin compaction. Recent research has focused on many facets of protamine biology, including protamine gene and protein structure/function relationships, mechanisms of protamine expression regulation and involvement of the protamines in male fertility. In this paper, we review our current understanding of the structure and function of the protamine-1 (P1) and protamine-2 (P2) proteins and genes, the expression and regulation of these genes and the relationship between the protamines and male fertility. In addition, we offer a brief outlook on future investigation into protamine proteins.

Amino Acid Sequence↗