Quantitative Abnormalities of Aα Chain Molecular Weight in the Fibrinogen of Cirrhotic Patients

Mapping Intimacies ◽

10.1055/s-0039-1680579 ◽

1977 ◽

Author(s):

Mark Weinstein ◽

Daniel Deykin

Keyword(s):

Molecular Weight ◽

Plasma Proteins ◽

Normal Subjects ◽

Small Samples ◽

Two Stage ◽

Large Pore ◽

Total Range ◽

Cirrhotic Patients ◽

Electrophoretic Procedure ◽

Molecular Weight Heterogeneity

A novel two-stage SDS gel electrophoretic procedure was devised to examine the molecular weight heterogeneity of fibrinogen in small samples of whole plasma from 12 normal and 7 cirrhotic individuals. Fibrinogen was first separated from other plasma proteins on a large pore gel, cut out of the gel, reduced, and separated into its component Aα, Bβ, and γ chains on a second gel. Two major mol wt species—fibrinogen I and II—were observed on the first gel. The ~ 25000 mol wt difference between these two forms reflected a decrease primarily in the size of one of the fibrinogen II Aα chains. In both normals and cirrhotic patients fibrinogen II comprised 30% of the total (range 20–35%). Fibrinogen I and II each contained two major high mol wt Aα chains—Aα/1 and a smaller Aα/2—that differ by 3000 mol wt. In normal fibrinogen I, Aα/2 comprised 33% of the total Aα chains (range 27–41%). In contrast the fibrinogen I of 6 out of the 7 patients had a lower per cent of Aα/2 (range 10–25%). Similar quantitative differences were seen in the decreased fraction of Aα/2 in the fibrinogen II of cirrhotic patients compared to normals. No correlation was found between per cent fibrinogen II and per cent Aα/2 in either normal subjects or cirrhotics. These results suggest that at least two independent processes are responsible for the observed levels of Aα chain heterogeneity in normals and cirrhotics and that one of these processes yields a lower than normal fraction of Aa/2 chains in the fibrinogen of cirrhotic individuals.

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Glomerular Permeability to High Molecular Weight Dextrans in Acute Ischaemic Renal Failure and Postural Proteinuria

Clinical Science ◽

10.1042/cs0380093 ◽

1970 ◽

Vol 38 (1) ◽

pp. 93-99 ◽

Cited By ~ 3

Author(s):

Pamela R. MacLean ◽

J. J. B. Petrie ◽

J. S. Robson

Keyword(s):

Molecular Weight ◽

Renal Failure ◽

High Molecular Weight ◽

Plasma Protein ◽

Healthy Subjects ◽

Plasma Proteins ◽

Normal Subjects ◽

Glomerular Permeability ◽

Molecular Weight Range ◽

Postural Proteinuria

1. Renal permeability to dextran of a molecular weight range approximating to that of the plasma proteins has been studied in six patients with acute ischaemic renal failure, four patients with postural proteinuria and six healthy subjects. 2. Results are expressed in terms of dextran selectivity indices which relate the clearance of dextran to its molecular weight. Indices of dextran selectivity were found to be high in acute ischaemic renal failure, postural proteinuria and in normal subjects. Comparable indices of plasma protein selectivity in these groups were low. 3. It is suggested that in postural proteinuria and acute ischaemic renal failure the proteinuria is not glomerular in origin, and that in these conditions macromolecules are filtered quite normally and urinary protein arises from a post glomerular source characterized by a lack of selectivity.

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Parallel Reduction of Plasma Levels of High and Low Molecular Weight Kininogen in Patients with Cirrhosis

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614849 ◽

1999 ◽

Vol 82 (11) ◽

pp. 1428-1432 ◽

Cited By ~ 9

Author(s):

Cheryl Scott ◽

Francesco Salerno ◽

Elettra Lorenzano ◽

Werner Müller-Esterl ◽

Angelo Agostoni ◽

...

Keyword(s):

Molecular Weight ◽

Liver Disease ◽

Liver Function ◽

Plasma Levels ◽

Plasma Concentrations ◽

Normal Subjects ◽

Low Molecular Weight ◽

Major Band ◽

Sds Page ◽

Normal Controls

SummaryLittle is known about the regulation of high-molecular-weight-kininogen (HK) and low-molecular-weight-kininogen (LK) or the relationship of each to the degree of liver function impairment in patients with cirrhosis. In this study, we evaluated HK and LK quantitatively by a recently described particle concentration fluorescence immunoassay (PCFIA) and qualitatively by SDS PAGE and immunoblotting analyses in plasma from 33 patients with cirrhosis presenting various degrees of impairment of liver function. Thirty-three healthy subjects served as normal controls. Patients with cirrhosis had significantly lower plasma levels of HK (median 49 μg/ml [range 22-99 μg/ml]) and LK (58 μg/ml [15-100 μg/ml]) than normal subjects (HK 83 μg/ml [65-115 μg/ml]; LK 80 μg/ml [45-120 μg/ml]) (p < 0.0001). The plasma concentrations of HK and LK were directly related to plasma levels of cholinesterase (P < 0.0001) and albumin (P < 0.0001 and P < 0.001) and inversely to the Child-Pugh score (P < 0.0001) and to prothrombin time ratio (P < 0.0001) (reflecting the clinical and laboratory abnormalities in liver disease). Similar to normal individuals, in patients with cirrhosis, plasma HK and LK levels paralleled one another, suggesting that a coordinate regulation of those proteins persists in liver disease. SDS PAGE and immunoblotting analyses of kininogens in cirrhotic plasma showed a pattern similar to that observed in normal controls for LK (a single band at 66 kDa) with some lower molecular weight forms noted in cirrhotic plasma. A slight increase of cleavage of HK (a major band at 130 kDa and a faint but increased band at 107 kDa) was evident. The increased cleavage of HK was confirmed by the lower cleaved kininogen index (CKI), as compared to normal controls. These data suggest a defect in hepatic synthesis as well as increased destructive cleavage of both kininogens in plasma from patients with cirrhosis. The decrease of important regulatory proteins like kininogens may contribute to the imbalance in coagulation and fibrinolytic systems, which frequently occurs in cirrhotic patients.

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Soluble Fibrin Complexes and Fibrinogen Heterogeneity in Diabetes mellitus

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650102 ◽

1980 ◽

Vol 44 (03) ◽

pp. 130-134 ◽

Cited By ~ 14

Author(s):

E B Tsianos ◽

N E Stathakis

Keyword(s):

Diabetes Mellitus ◽

Molecular Weight ◽

Plasma Proteins ◽

Polyacrylamide Gel Electrophoresis ◽

Gel Filtration ◽

Lower Molecular Weight ◽

Polyacrylamide Gels ◽

Soluble Fibrin ◽

Α2 Macroglobulin ◽

Patients With Diabetes

SummaryThe presence of soluble fibrin complexes (SFC) measured by gel filtration of plasma on 4% agarose columns, fibrinogen heterogeneity on 3.5% SDS-polyacrylamide gels and the concentrations of several plasma proteins were evaluated in 39 patients with diabetes mellitus (DM) and 19 matched control subjects. A small but significant increase of SFC was found in DM (p<0.01). On individual basis 51.2% of the patients had increased SFC (>M + 2 SD of the controls). Polyacrylamide gel electrophoresis of the SFC showed no evidence of cross-linking or proteolysis. Plasma clots formed in the presence of EDTA and trasylol were analysed in SDS-polyacrylamide gels in a normal and two lower molecular weight fibrin bands (band I, II, III). The percentage of band I fibrinogen was in diabetics (65.3 ± 4.7%) lower than that of the controls (71.8 ± 4.5%) (p < 0.01). Fibrinogen levels, antithrombin III, α1-antitrypsin, α2-macroglobulin and plasminogen were significantly increased in DM. We suggest that in DM there is an enhancement of intravascular fibrin formation and accelerated fibrinogen degradation to lower molecular weight forms.

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Comparison of the Non-Specific Binding of Unfractionated Heparin and Low Molecular Weight Heparin (Enoxaparin) to Plasma Proteins

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649639 ◽

1993 ◽

Vol 70 (04) ◽

pp. 625-630 ◽

Cited By ~ 71

Author(s):

Edward Young ◽

Benilde Cosmi ◽

Jeffrey Weitz ◽

Jack Hirsh

Keyword(s):

Molecular Weight ◽

Unfractionated Heparin ◽

Plasma Proteins ◽

Low Molecular Weight Heparin ◽

Specific Binding ◽

Anticoagulant Activity ◽

Factor Xa ◽

Low Molecular Weight ◽

Heparin Binding ◽

Fixed Amount

SummaryThe non-specific binding of anticoagulantly-active heparin to plasma proteins may influence its anticoagulant effect. We used low affinity heparin (LAH) essentially devoid of anti-factor Xa activity to investigate the extent and possible mechanism of this non-specific binding. The addition of excess LAH to platelet-poor plasma containing a fixed amount of unfractionated heparin doubled the anti-factor Xa activity presumably because it displaces anticoagulantly-active heparin from plasma proteins. Although dextran sulfates of varying molecular weights also increased the anti-factor Xa activity, less sulfated heparin-like polysaccharides had no effect. These findings suggest that the ability to displace active heparin from plasma protein binding sites is related to charge and may be independent of molecular size. In contrast to its effect in plasma containing unfractionated heparin, there was little augmentation in anti-factor Xa activity when LAH was added to plasma containing low molecular weight heparin (LMWH), indicating that LMWH binds less to plasma proteins than unfractionated heparin. This concept is supported by studies comparing the anticoagulant activity of unfractionated heparin and LMWH in plasma with that in buffer containing antithrombin III. The anti-factor Xa activity of unfractionated heparin was 2-fold less in plasma than in the purified system. In contrast, LMWH had identical anti-factor Xa activity in both plasma and buffer, respectively. These findings may be clinically relevant because the recovered anti-factor Xa activity of unfractionated heparin was 33% lower in plasma from patients with suspected venous thrombosis than in plasma from healthy volunteers. The reduced heparin recovery in patient plasma reflects increased heparin binding to plasma proteins because the addition of LAH augmented the anti-factor Xa activity. In contrast to unfractionated heparin, there was complete recovery of LMWH added to patient plasma and little increase of anti-factor Xa activity after the addition of LAH. These findings may explain why LMWH gives a more predictable dose response than unfractionated heparin.

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Low Molecular Weight Heparin Therapy: Is Monitoring Needed?

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648866 ◽

1994 ◽

Vol 72 (03) ◽

pp. 330-334 ◽

Cited By ~ 72

Author(s):

B Boneu

Keyword(s):

Molecular Weight ◽

Clinical Trials ◽

Plasma Proteins ◽

Bleeding Risk ◽

Heparin Therapy ◽

Low Molecular Weight ◽

Vein Thrombosis ◽

Meta Analyses ◽

Deep Vein ◽

Initial Check

SummaryRecent meta-analyses indicate that low molecular weight heparins (LMWH) are more effective than unfractionated heparin (UH) in preventing and treating deep vein thrombosis. This article presents the arguments for and against the need for laboratory monitoring. At the present time, the only tests currently available for monitoring LMWH therapy are those which measure the anti Xa activity in the plasma. Due to lower binding to plasma proteins and to cell surfaces,the plasma anti Xa activity generated by a given dose of LMWH is more predictable than for UH.Some clinical trials suggest that LMWH delivered at the recommended dose expose the patient to less bleeding risk than UH. Several . meta-analyses indicate comparable risk while any overdose unaccept-ably increases the haemorrhagic risk. The lowest dose of LMWH still effective in treating established DVT is presently unknown; some reports indicate that inadequate doses of LMWH are associated with a lack of efficacy for prevention. An overview of the published clinical trials indicates that the LMWH dose has never been monitored for prevention of DVT. In the treatment of established DVT, several trials have been performed without any monitoring, while in others the dose was adapted to target a given anti Xa activity. These considerations suggest that in prevention of DVT, monitoring the dose is not required. In the treatment of established DVT, considering the haemorrhagic risk of LMWH, the risk of undertreating the patient and the absence of large clinical trials comparing the advantages of monitoring the dose or not, it might be useful to check anti Xa activity at least once at the beginning of the treatment but the need for this initial check remains to be established. Because a large proportion of patients will be in the desired range, dose adjustments will be far less frequent than for UH.

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Neutralisation of Heparan Sulphate and Low Molecular Weight Heparin by Protamine

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661242 ◽

1985 ◽

Vol 53 (01) ◽

pp. 086-089 ◽

Cited By ~ 22

Author(s):

A R Hubbard ◽

C A Jennings

Keyword(s):

Molecular Weight ◽

Plasma Proteins ◽

Low Molecular Weight Heparin ◽

Heparan Sulphate ◽

Activated Partial Thromboplastin Time ◽

Weight Basis ◽

Low Molecular Weight ◽

Protamine Sulphate ◽

At Iii ◽

Reference Preparation

SummaryThe neutralisation by protamine sulphate (PS) of heparan sulphate (HS), a low molecular weight heparin (LMWH), and a reference preparation of unfractionated heparin (UH), was studied by activated partial thromboplastin time (APTT) and anti-Xa clotting assays. UH was most easily neutralised in the APTT assay by PS (on a weight for weight basis), followed by LMWH and HS. The neutralisation of APTT activity by PS closely followed the loss of activity in the anti-Xa clotting assay, when plasma was used as the source of At III. When the anti-Xa clotting assay was carried out using purified At III in place of plasma, HS and LMWH were neutralised by much lower amounts of PS and resembled UH neutralisation more closely. Resistance of HS anti-Xa activity to PS neutralisation decreased with increasing plasma dilution. The presence of bovine albumin with purified At III concentrate increased the resistance of HS to PS neutralisation. It is concluded that PS binding to UH, HS and LMWH is probably related more to their degree of sulphation than molecular weight and that non-specific interactions between PS and plasma proteins inhibit the binding of PS to HS and LMWH.

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