Contact Factors in Health and Disease

Saito, Hidehiko

doi:10.1055/s-2007-1003474

Cited by 76 publications

(48 citation statements)

References 97 publications

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“…In fact, contact system activation leads to initiation of the intrinsic pathway of blood coagulation in vitro. However, the contact system is considered to have little influence on physiological hemostasis, because deficiencies of contact factors are not associated with clinical bleeding despite marked prolongation of APTT (11). Recent investigations suggest that contact factors have anti-coagulation and profibrinolytic functions in a physiological milieu (45,46).…”

Section: Discussionmentioning

confidence: 99%

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A Mosquito Salivary Protein Inhibits Activation of the Plasma Contact System by Binding to Factor XII and High Molecular Weight Kininogen

Isawa

Yuda

Orito

et al. 2002

Journal of Biological Chemistry

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The salivary glands of female mosquitoes contain a variety of bioactive substances that assist their bloodfeeding behavior. Here, we report a salivary protein of the malarial vector mosquito, Anopheles stephensi, that inhibits activation of the plasma contact system. This factor, named hamadarin, is a 16-kDa protein and a major component of the saliva of this mosquito. Assays using human plasma showed that hamadarin dose-dependently inhibits activation of the plasma contact system and subsequent release of bradykinin, a primary mediator of inflammatory reactions. Reconstitution experiments showed that hamadarin inhibits activation of the plasma contact system by inhibition of the reciprocal activation of factor XII and kallikrein. Direct binding assays demonstrated that this inhibitory effect is due to hamadarin binding to both factor XII and high molecular weight kininogen and interference in their association with the activating surface. The assays also showed that hamadarin binding to these proteins depends on Zn 2؉ ions, suggesting that hamadarin binds to these contact factors by recognizing their conformational change induced by Zn 2؉ binding. We propose that hamadarin may attenuate the host's acute inflammatory responses to the mosquito's bites by inhibition of bradykinin release and thus enable mosquitoes to take a blood meal efficiently and safely.

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Section: Discussionmentioning

confidence: 99%

“…At the same time, generated factor XIIa converts factor XI to XIa, initiating the intrinsic pathway of blood coagulation. However, the physiological significance of this pathway in initiation of blood coagulation in vivo appears questionable (11).…”

mentioning

confidence: 99%

A Mosquito Salivary Protein Inhibits Activation of the Plasma Contact System by Binding to Factor XII and High Molecular Weight Kininogen

Isawa

Yuda

Orito

et al. 2002

Journal of Biological Chemistry

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“…' Human plasma prekallikrein (PK), a singlechain glycoprotein (MW = 85 kD), required for the activation of the kinin-forming pathway, is synthesized mainly in the liver. [2][3][4] Decreased plasma PK levels were observed in patients with chronic active hepatitis or liver cirrhosis.>" and it has been suggested that plasma PK levels are determined by the rate of liver protein synthesis, thereby reflecting residual functional liver mass." Presumably, changes in the expression of certain genes, as observed in neoplastic processes, might induce increased levels of plasma PK.…”

Section: Additional Key Phrases: Hepatocellularcarcinoma;plasma Prekamentioning

confidence: 99%

Plasma Prekallikrein Levels in Patients with Hepatocellular Carcinoma and Liver Cirrhosis: A Pilot Study

et al. 1993

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SUMMARY. The concentration of plasma prekallikrein (PK) in five patients with hepatocellular carcinoma (HCC) has been measured and related to levels in 18 patients with liver cirrhosis (LC) and 30 healthy subjects. It was found that the mean PK level was significantly increased in patients with HCC, while patients with LC demonstrated lower concentrations, as compared with healthy subjects. The results indicate that PK might be useful in screening cirrhotic patients for HCC. Longitudinal studies of PK in a larger group of patients at risk of developing HCC are therefore recommended.

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“…25) Hageman trait is an extremely rare disorder of blood coagulation transmitted in an autosomal recessive mode, usually with an asymptomatic course. 3,8,26,31) We treated a patient with severe FXII deficiency who presented with a subdural hematoma.…”

Section: Introductionmentioning

confidence: 99%

Subdural Hematoma in a Patient With Hageman Trait-Case Report-

Kaspera

Rothkegel²,

Stadnicki

2005

Neurol. Med. Chir.(Tokyo)

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A 61-year-old man with severe factor XII deficiency presented with a subdural hematoma appearing as mixed but mainly high density by computed tomography in the left frontotemporoparietal region. No cranial injury was reported in the medical history of the patient. Clotting system study showed less than 1% functional activity of factor XII, whereas the levels of the other clotting factors were within the normal ranges. Partially clotted and hemolyzed subdural hematoma was removed through a craniotomy. The postoperative course was uneventful. The patient later died of severe circulatoryrespiratory failure. We believe that the subdural hematoma may have developed as a result of a minor head trauma sustained in the past. We suggest that impairment of fibrinolytic activation related to severe factor XII deficiency might have contributed to the delay of dissolution of the subdural hematoma which, under ordinary circumstances, would have formed chronic subdural hematoma.

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Contact Factors in Health and Disease

Cited by 76 publications

References 97 publications

A Mosquito Salivary Protein Inhibits Activation of the Plasma Contact System by Binding to Factor XII and High Molecular Weight Kininogen

A Mosquito Salivary Protein Inhibits Activation of the Plasma Contact System by Binding to Factor XII and High Molecular Weight Kininogen

Plasma Prekallikrein Levels in Patients with Hepatocellular Carcinoma and Liver Cirrhosis: A Pilot Study

Subdural Hematoma in a Patient With Hageman Trait-Case Report-

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