bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECTS OF VITAMIN K ON VITAMIN K DEPENDENT PROTEINS IN NEWBORN INFANTS
Authors: YAMADA K , MEGURO T , SHIRAHATA A , NAKAMURA T , ASAKURA A 
Published: June 2019

Plasma levels of vitamin K (VK) and VK dependent proteins ( factor E, factor VH, factor X, protein C and osteocalcin)were determined before and after VK administration to 22 newborn infants. Vitamin K2 syrup ( 2 mg/kg of body weight ) was orally administered to 9 healthy premature, 11 high risk and 2 VK deficient infants under 3 days of age. VK families extracted from plasma were separated by high performance liquid chromatography using a Cosmosil 5 Ci8 column, and separated VK families were detected by a fluorometry after their reaction with ethanolic sodium borohydride in a reaction coil connected by one-line to a chromatographic column. Total activity of factor E, factor VE and factor X was assayed by a Normotest ( Nyegaard ), and protein C was measured by protac/APTT and protac/chromogenic substrate ( S-2366 ) functional assay system ( American Diagnostica ). Osteocalcin levels were assayed by using of a RIA method before and after the absorption of plasma by hydroxyapatite.After VK administration, plasma VK2 ( menaquinone-4 ) content increased from levels less than 0.012yg/ml to levels between 15.9 and 70.9μg/ml, excluding one case in whom plasma VK was not detected after VK administration. Compared with Normotest values and osteocalcin levels of age-matched healthy newborn infants treated without VK, premature, high risk and VK deficient infant levels significantly increased after 24 hrs and after 7 days of VK administration. No correlation was seen between the increase of plasma VK contents and the increase of Normotest values after VK administration. On the other hand, no significant increase of protein C assayed by both methods was observed in healthy premature and high risk infants after VK administration.These results indicate that the change of protein C after VK treatment is different from that of factor II, VII, X and osteocalcin.
PREDICTIVE VALUE OF LOW AT III LEVELS FOR THE OCCURRENCE OF IVH, IRDS AND DEATH IN PREMATURE NEONATES
Authors: van den Berg W , Peters M , Breederveld C , ten Cate J W , Koppe J G 
Published: June 2019

The observation of AT III deficiency in premature neonates with Idiopathic Respiratory Distress Syndrome (IRDS), suggests a positive predictive value for a poor outcome. The underlying diffuse intravascular coagulation could generate serious hemorrhagic complications like Peri/Intraventricular Hemorrhage (IVH).A prospective study was performed in consecutively born neonates to assess the predictive value of low AT III for theoccurrence of IVH, (gr. III/IV), IRDS, and death. Eighty-one neonates were included in the study during a period of 5 months. AT III levels were determined immediately after birth by a chromogenic substrate assay. Values in umbilical cord blood were identical with values in capillary or peripheral vein blood samples taken within 6 hours after birth. There was no correlation between AT III values and gestational age (r: 0.18). Twenty-four neonates with IRDS showed a mean AT III value of 0.23 U/ml (S. D. ± 0.07 U/ml) which was significantly lower than a mean AT III value of 0.35 U/ml (S. D. ± 0.1 U/ml) for neonates without IRDS (p ≺0.00005). When IVH gr. III/IV was diagnosed in neonates having IRDS (8/24) no significant difference in mean AT IIIact was observed with respect to jnean AT III levels of remaining neonates without this complication. No death occurred in neonates without IRDS. Mean AT IIIact (0.21 U/ml) in neonates with IRDS who died (9/24) was low compared with mean AT III levels of neonates with IRDS who survived (0.25 U/ml), but did not reach significance (p≻0.1). Assuming a critical value of AT III of 20% a positive predictive value of 89% for IRDS, 44% for IVH, and 56% for death was calculated. It is concluded that low AT Illact levels have a high predictive value for IRDS.
PROSTACYCLIN PRODUCTION BY UMBILICAL ARTERIES FROM PREGNANCIES COMPLICATED BY SEVERE PREGNANCY INDUCED HYPERTENSION
Authors: McLaren M , Greer I T A , Forbes C D 
Published: June 2019

Approximately ten per cent of allpregnancies are complicated by some degree of hypertensive disease. Since the level of blood pressure is closely related to foetal well-being, if the blood pressure is consistentlyelevated during pregnancy, there is an associated increase in perinatal mortality. Various workers have suggested involvement of prostaglandins in the pathogenesis of pregnancy induced hypertension (PIH). One of our previous studies showed unrecordablelevels of plasma prostacyclin metabolites (PGI2m) of <5pg/ml in all hypertensive patients during the third trimester, whereas none of the normalgroup developed unrecordable levels at any stage.In this study we used an umbilical artery perfusion model to compare the ability of normal platelet poor plasma, which has been shown to contain a PGI2 stimulating factor, to stimulate production of PGI2 from arteries from normal pregnancies and pregnancies complicated by PIH. Arteries from two patients suffering from PIH with persistent diastolic pressure of >90mm mercury were exhausted of spontaneous PGI2 production beforeperfusion with normal platelet poor plasma. In each case an artery from a normal pregnancy was used as a control. In each experiment levels of PGI2 rose from a baseline level of<50pg/ml to <1000 pg/ml in the normal arteries, whereas the arteries from PIH patients showed no significant rise. It would seem therefore that ourfinding of unrecordable levels of plasma PGI2m in hypertensive pregnancies may be related to defective endothelial cell production.
CONGENITAL HYPOFIBRINOGENEMIA, DEEP VEIN THROMBOSIS AND RECURRENT PLACENTAL ABRUPTION
Authors: Godal H C , Brosstad F , Holm B 
Published: June 2019

A patient with hypofibrinogenemia, deep vein thrombosis and recurrent placental abruption is reported. The persistently low plasma fibrinogen concentration strongly suggested that the condition was inherited, and this was supported by low fibrinogen levels and thrombosis tendency in the patient's brother. The exact nature of the condition is not known, but the close agreement between the clottable and immunologic fibrinogen -indicates the presence of a hyperfibrinogenemia sensu stricte rather than dysfibrinogenemia, and this was supported by uniformly negative tests to detect fibrinogen abnormalitied.Up to now, less than 50 cases of congenital hypofibrinogenemia have been reported. It is not entirely clear whether hypofibrinogenemia represents the heterozygous form of afibrinogenemia or whether itrepresents some sort- of dysfibrinogenemia with abnormal rate of biosynthesis but normal clotting and crosslinking functions. Four of the reported patients with hypofibrinogenemia had placental abruption, a complication which occursin less than of pregnancies. In addition, a relatively high proportion of patients withcongenital hypofibrinogenemiahad increased tendency to thrombosis. On this background it is tempting to speculate that the elevated fibrinogen during pregnancy serves other functions than to facilitate the formation of haemostatic plugs. Thus, during pregnancy and other socalled "acute phase" situations, minute amounts of fibrin may be generatedwithin the circulating blood. Since, moreover, the solvent for these fibrin molecules isfibrinogen, the possibility exists that hyperfibrinogenemia contributes to the prevention of thromboembolism by keeping trace amounts of fibrin in solution.
ANTICOAGULANT AND ANTIGENIC LEVELS OF PROTEIN C AND PROTEIN S IN PATIENTS ON STABILIZED ORAL ANTICOAGULANT TREATMENT
Authors: D'Angelo A , Gilardoni F , Seveso M P , Poli P , Quintavalle R , Manotti C 
Published: June 2019

Isolated deficiencies of protein C and protein S, two vitamin K-dependent plasma proteins, constitute about 70% of the congenital abnormalities of blood coagulation observed in patients with recurrent venous thrombosis beLow the age of 40. The laboratory diagnosis of congenital deficiency of these proteins represents a major problem since a large proportion of patients are on oral anticoagulation (OA) at the time the deficiencies are suspected.Under these circumstances the availability of a reference interval obtained in patients on stabilized OA has proven useful.Functional (C) and antigenic levels (Ag) of protein C, protein S, factor IX and II were estimated in 136 patients on stabilized OA, subdivided according to the degree of anticoagulation (Internatio nal Normalized Ratio, INR).The results indicate that with increasing anticoagulation the activity levels of all the vitamin K-dependent factors decrease to a greater extent than the corresponding antigenic levels. At variance with the other factors, total protein S antigen levels are only moderately reduced by OA with protein S anticoagulant activi ty comparing well to factor IX clotting activity. These data suggest the possibility of identifying both quantitative and qualita tive deficiencies of protein C and protein S in patients on oral anticoagulant treatment.
PLASMA LEVELS OF PROTEIN S AND C4b-BINDING PROTEIN DURING TREATMENT WITH L-ASPARAGINASE
Authors: Viganò D'Angelo S , Gugliotta L , Gilardoni F , Macagni A , Chetti L , D'Angelo A 
Published: June 2019

Protein S (PS), the cofactor of activated protein C (PC), circulates in plasma as free PS (active) and in complex with C4b-binding protein (inactive). We have followed the changes of total PS, free PS, PS activity and C4b-binding protein in 5 adult patients with acute lymphoblastic leukemia treated with 20,000 IU/sqm L-asparaginase (L-ASE) administered three times weekly for two weeks (6 doses) and compared them to the changes of PC antigen and activity, antithrombin III and fibrinogen. The table shows the mean values of these parameters (% of pretreatment values) observed after three doses of L-ASE (A), after completion of treat ment (B) and one week after the end of treatment (C).These data suggest that at variance with PC and similar to fibri nogen and antithrombin III, total PS antigen is still reduced af ter one week from the end of L-ASE treatment. The reduction of total PS reflects that of free PS, as predicted by mass action. On the contrary, PS anticoagulant activity is decreased to a higher extent than total PS antigen. Acquired PS deficiency might play a contributory role to the development of thrombotic comply cations in patients receiving L-ASE.Supported in part by CNR grant n 85.02200.44
The Effect of Endotoxins on Generation of Thrombin in the Platelet Atmosphere
Authors: Vermylen J. , Fumarola D. , Semeraro N. 
Published: June 2019

Human platelets, washed by repeated albumin density gradient centrifugation, aggregate strongly, occasionally in 2 waves, 3 to 5 minutes after addition of both calcium ions (2.10−3 M f.c.) and one tenth volume normal human serum, provided the serum contains at least 0.6% residual prothrombin. This aggregation is prevented by heparin or hirudin. Samples removed at the onset of aggregation rapidly clot purified fibrinogen, whereas the serum-CaCl2 mixture alone does not clot purified fibrinogen within 24 hours. It is therefore concluded that thrombin is rapidly generated in the platelet atmosphere.The in vitro effect of endotoxins on human, in contrast to rabbit, platelets is not well established. Using eight different bacterial lipopolysaccharides we failed to demonstrate aggregation in human platelet-rich plasma or of washed platelets or to find significant 14C-serotonin release. On the other hand, all these endotoxins in a final concentration of 100 μg/ml consistently shortened the latent period before aggregation in the washed platelets-serum-CaCl2 system. It is concluded that bacterial endotoxins enhance the generation of thrombin in the atmosphere of human platelets.
Effect of ADP and Thrombin on Fibrin Retraction Inducde by Human Platelets and Fibro-Blasts
Authors: Niewiarowski S. , Stewart G. J. , Goldstein S. 
Published: June 2019

Clots formed upon addition of thrombin to suspensions of human platelets (107–109/ml) or of cultured human skin fibroblasts (2 × 106/ml) and fibrinogen (0.1%) retracted within 10–120 min at 37°C., however, when thrombin was substituted with Bothrops marajoensis thrombin like enzyme (BM enzyme) no retraction occurred. ADP (50 η moles) and low concentrations of thrombin (0.01–0.1 units) stimulated platelets to retract clots formed with BM enzyme. This type of clot retraction was inhibited by apyrase and creatine phosphate kinase in the presence of creatine phosphate but that induced by higher concentrations of thrombin (2 units) was not affected. Since thrombin releases ADP from platelets it is possible that clot retraction induced by low concentrations of thrombin is mediated by ADP. On the other hand high concentrations of thrombin may promote clot retraction independently of ADP. As tested by firefly method fibroblasts contained 12 n moles ATP and 4 n moles ADP per mg protein, a value closely ressembling that of nor metabolic adenine nucleotides in platelets. Thrombin did not cause release of adenine nucleotides from fibroblasts nor did addition of ADP stimulate fibroblasts to retract fibrin. These data support the view that the response to ADP is a specific cellular property of platelets and suggest that both types of cells may have similar receptors sensitive to thrombin.(Aided by grants HL 15226 and HL 14217 from N.I.H. and MA-3515 from the Medical Research Council of Canada.)
γ’-Dimer Antibody and its Specificity Against Fibrinogen, FR-a and Carboxymethylated chains from Fibrinogen and Cross-linked Fibrin
Authors: Clausen N. T. , Gormsen J. 
Published: June 2019

γ’-dimers (M: 80.000) were obtained from fully cross-linked fibrin (Kabi, grade L, 96% clottable) by digestion with porcine plasmin (0.5 CTA units/mg protein) for 18 h., carboxymethylation and subsequent isolation on Whatman CM-52 with a combined pH (4.8 → 5.5) and ionic strength (0.05 → 0.25 M) gradient in Na-acetate buffer with 8 M urea*).The γ’-dimers were recycled once and exhibited purity on SDS polyacrylamide gel electrophoresis. These γ’-dimers showed weak reaction in immunoprecipitation assays with anti-fibrinogen and anti-D but not with anti-E rabbit immunserum.Heterologous antibody was obtained from rabbit after subcutaneous injections of γ’-dimer antigen and bleeding after 4 months, 14 days after last injection.This crude antibody reacted in immunodiffusion and monorocket immunoelectrophoresis with γ’-dimers and weakly with fibrinogen and fragment D but not with fragment E (DEAE purified). After absorption with fibrinogen and fractional desalting with (NH4)2SO4 (25% and 50%) there was no reaction with fibrinogen, D or E fragments, but still with γ’-dimers.Testing against isolated chains (SDS-pure) from fibrinogen revealed Aα cross-reaction but only reaction with γ and γ’-dimer chains remained after proper absorption. Possible differentiation between these two subunit structure is reported.* Murano, G. et al. FEBS-letters 14, 37–41, 1971.
Recovery of the Venous Wall from Leukocyte Induced Injury
Authors: Stewart G. J. , Ritchie W. G. M. , Lynch P. R. 
Published: June 2019

Surgical trauma to tissue adjacent to canine jugular veins combined with brief local stasis caused massive leukocyte invasion of venous walls. This resulted in the entrapment of pockets of leukocytes between the endothelium and basement membrane and subsequent detachment of patches of endothelium.By an hour smooth muscle showed a decrease in myofibrils and an increase in rough endoplasmic reticulum and collagen lost its ability to stain with uranyl acetate-lead citrate.By 24 hours smooth muscle cells had undergone various changes and formed a partial covering layer over the surface of denuded areas, often by extending long “arms” from a bulky, fibroblast-like “body”. Various stages of de-differentiation and re-differentiation were abundant. By 72 hours these cells had become thinner and resembled the “immature” endothelium of Florey and others. However, the sheet was still discontinuous. By 7 days and thereafter to 28 days the endothelium was continuous and typical of “immature” endothelium morphologically but the surface membrane stained intensely in some instances.At 24 hours there was a perivascular zone of edema with cell ghosts and amorphous debris which decreased thereafter. Collagen staining was again typical by 7 days.These observations indicate that the luminal surface of blood veins can be initially repaired by the rapid de-differentiation and re-differentiation of smooth muscle rather than waiting for the ingrowth of endothelial cells from the margins of the denuded areas.(Supported by N. I. H. Grants ≠ HL 14217 and HL 08886.)
Binding of Collagen to Platelets
Authors: Jaffe R. M. , Deykin D. 
Published: June 2019

Type I (chick calvaria) and Type II (chick cartilage) collagen were synthesized in organ culture on tritiated amino acids. The final, purified collagen has sp. act. > 106 DPM/mg. protein.
3H-Tropocollagen, from 5000–40,000 molecules per platelet, does not bind during a 15 minute observation period. Multimeric collagen, at the same dose, binds to platelets after a lag period of 90–120 sec. Fibrillar collagen will bind within 10 sec. Gelatin, prepared from this radiolabeled collagen, does not bind during the observation period. Similar results obtain for both Type I and Type II collagen.Aggregation and binding studies were carried out simultaneously. Tropocollagen does not initiate aggregation; multimeric collagen initiates aggregation after a lag of about 180 seconds; fibrillar collagen initiates aggregation with a lag of about 60 seconds. Gelatin does not initiate aggregation. Thus binding precedes aggregation by about 60 seconds. These observations are consistent with a quaternary requirement for platelet aggregation induced by collagen.Chemical modification of ॉ-amino groups of lysine residues in collagen was performed. Certain modifications inhibit fibrillogenesis and/or denature the protein. These modifications inhibit collagen-induced platelet aggregation. Permethylation of lysines in collagen does not impair fibrillogenesis, does not denature the protein and does not inhibit collagen-induced platelet aggregation.
Quantitative Determination of Collagen-platelet Binding
Authors: Kronick P. L. , Jimenez S. A. 
Published: June 2019

We have investigated the structural features of the collagen molecule necessary for adhesion to platelets. The use of biosynthesized14–proline labelled collagens allowed us to measure directly and quantitatively the very small amounts of chicktendon and cartilage collagen protomers which bind to platelets and compare their binding with that of the corresponding fibrils. The binding of fibrillar aggregates separated by centrifugation was found to increase with sedimentation coefficient up to a limit of s = 15-S. The fraction of 15-S aggregates bound was at least four fold greater than that of 5-S aggregates. The highly glycosylated cartilage collagen allowed to aggregate at 4° C by prolonged storage yielded a product 50% of which bound to platelets ; fresh cartilage collagen and procollagen bound less than 5% both at 4° C and 37° C. Lowering the pH from 7.4 to 6.5 had no effect on the binding of the aggregates.The quantitative binding parameters which we have determined show that collagen must be in an aggregated form to bind to platelets ; the extent of glycosylation does not exert a great effect on the binding tendency and the amount of collagen in protomeric form which can bind to a platelet under physiologic conditions is very small.(Supported by NIH Contract No. 1-HB-42982.)
Collagen Coated Gelatine Tubes for the Investigation of Platelet Adhesion and Subsequent Platelet Aggregation Under Controlled flow Conditions
Authors: Muggli R. , Baumgartner H. R. 
Published: June 2019

Aggregometer studies do not discriminate between platelet adhesion and platelet aggregation. Therefore, we prepared a homogenous collagen surface which could be exposed to whole blood in a perfusion chamber under controlled flow conditions.Artificial “vessel” segments were prepared by dipping glass rods into 20% gelatine and, after air-drying, cross-linking the gelatine in 2.5% glutaraldehyde. Segments of 1 cm length were then drawn on the rod of the perfusion chamber and coated with 300 μl of neutral salt soluble collagen (2.2 mg/ml). Surface coverage with collagen was virtually complete (96%–100%).Uncoated or collagen-coated gelatine segments were exposed to citrated rabbit blood for periods up to 40 min. Platelet-surface interaction was evaluated morphometrically. On uncoated segments surface coverage with platelets amounted to 31% and 50% after 10 min and 40 min (the corresponding ratios of contact/spread platelets were 2.6 and 1.5). Only 0.1% thrombi were found. On collagen-coated segments surface coverage with platelets amounted to 57% and 83% after 10 min and 40 min (the corresponding ratios of contact/ spread platelets were 0.1 and 0.0); platelet thrombi were found on 33% and 42% of the surface after 10 min and 40 min.Platelet adhesion and subsequent aggregation on the collagen-coated artificial surface is similar to that observed on α-chymotrypsin digested subendothelium. The results suggest that fibrillar collagen triggers rapid spreading on a surface, a reaction which is closely associated with the formation of platelet thrombi. The latter phenomenon is thought to be caused by the release of aggregating agents from the spreading platelets.
Effect of Methotrexate and Vincristine on rat Bone marrow Megakaryocytes and Platelet Function
Authors: Jerushalmy Z. , Pinkhas J. , Krinsky M. , Vries A. de 
Published: June 2019

Methotrexate administered intraperitoneally to rats caused a transient disturbance in platelet function manifested by absence of ADP-induced aggregation and serotonin incorporation, and by decreased factor 3 (PF3) availability. These phenomena were noticed when the megakaryocyte count decreased while the platelet count was still within the normal range.Vincristine injection was not followed by an immediate drop in megakaryocyte and platelet count or PF3 availability, however a transient decrease of ADP-induced platelet aggregation and serotonin incorporation occurred.
Acetyisalicylic Acid (ASA) does not Prolong Bleeding Time in Rats
Authors: Stella L. , Donati M. B. , Gaetano G. de 
Published: June 2019

We have recently suggested (Thrombos. Diathes. haemorrh., 32, 242, 1974; Thrombos. Res., 1975, in press) that the role of platelets in the primary haeomostasis of rats may be questioned. Further evidence to this hypothesis is given by this study. Indeed, we have observed that ASA does not prolong the bleeding time in rats, whereas it inhibits in vitro collagen- or Thrombofax-induced aggregation of platelets obtained from the same animals after administration of the drug. Conscious Charles River rats, weighing 350 g., were used. Aspirin (Bayer) or lysine-acetylsalicylate (Flectadol, Maggioni) were given either per os or intrapertioneally at a dose of 200 mg/kg b.w. The effect on the bleeding time was measured 1 hour after the administration of the drug by 2 different techniques: either transecting the tip of the tails of paired animals or making 2 incisions on the tail of the same animal by an automatic, standardized template-like device (kindly provided by Prof. C. Praga, Milano). Preliminary experiments in control animals had shown no difference between the first and the second incision. The results are reported in the table.As can be seen, ASA not only did not prolong bleeding time, but markedly shortened it. The latter result was unexpected and we have no satisfactory explanation for ist.(Supported by Grant N. 73.00400.04 of the Italian Research Council (C. N. R.).)