Search

Biallelic GBA mutations cause Gaucher disease (GD), and heterozygous carriers are at risk for synucleinopathies. No founder GBA mutations in French‐Canadians are known. GBA was fully sequenced using targeted next generation and Sanger sequencing in French‐Canadian Parkinson disease (PD) patients (n = 436), rapid eye movement (REM)‐sleep behavior disorder (RBD) patients (n = 189) and controls (n = 891). Haplotype, identity‐by‐descent (IBD) and principal component analyses (PCA) were performed using single nucleotide polymorphism‐chip data. Data on GD patients from Toronto and Montreal were collected from patients' files. A GBA p.Trp378Gly mutation was identified in two RBD and four PD patients (1% of all patients combined), and not in controls. The two RBD patients had converted to DLB within 3 years of their diagnosis. Haplotype, IBD and PCA analysis demonstrated that this mutation is from a single founder. Out of 167 GD patients screened, 15 (9.0%) carried the p.Trp378Gly mutation, all in trans with p.Asn370Ser. Three (20%) of the GD patients with the p.Trp378Gly mutation had developed Parkinsonism, and 11 patients had family history of PD. The p.Trp378Gly mutation is the first French‐Canadian founder GBA mutation to be described, which leads to synucleinopathies and to GD type 1 when in compound heterozygosity with p.Asn370Ser. [ABSTRACT FROM AUTHOR]

Studies data showing that small babies receive the cardiovascular protective apolipoprotein epsilon-2 allele less frequently than expected. Allelic variants of the APOE gene which result in functional consequences at both cellular and molecular levels; Allele associated with lower total cholesterol and low density lipoprotein cholesterol.

Ultrastructural and immunofluorescent microscopic studies were performed on renal tissue obtained from nine patients during the acute and convalescent phase of the haemolytic uraemic syndrome (HUS). All had glomerular deposits of IgM in the absence of circulating immune complexes. This was associated with deposition of Clq during the acute phase, and properdin and C3 during the convalescent phase. C4 was consistently absent. Since such a pattern of complement deposition does not fulfil criteria either for alternate or classical pathway activation, the possibility of Clq bypass loop activation by IgM is suggested. [ABSTRACT FROM AUTHOR]

Objective: Cartilage repair elicited by bone marrow stimulation can be enhanced by a chitosan-glycerol phosphate (GP)/blood implant, through mechanisms involving therapeutic inflammatory angiogenesis. The implant is formed by in situ coagulation, which can be accelerated by adding coagulation factors. We hypothesized that coagulation factors enhance acute subchondral angiogenesis in repairing drilled defects., Design: Full-thickness cartilage defects were created bilaterally in 12 skeletally mature rabbit knee trochlea, microdrilled, then allowed to bleed as a control (N = 6) or treated with chitosan-GP/blood implant (N = 6), or implant solidified with thrombin (IIa), tissue factor (TF) with recombinant human factor VIIa (rhFVIIa), or rhFVIIa alone (N = 4 each condition). At 3 weeks post-operative, quantitative stereology was used to obtain blood vessel length (L(V)), surface (S(V)), and volume (V(V)) density at systematic depths in two microdrill holes per defect. Collagen type I, type II and glycosaminoglycan (GAG) percent stain in non-mineralized repair tissue were analysed by histomorphometry., Results: All drill holes were healing, and showed a depth-dependent increase in granulation tissue blood vessel density (Lv, Sv, and Vv, P < 0.005). Residual chitosan implant locally suppressed blood vessel ingrowth into the granulation tissue, whereas holes completely cleared of chitosan amplified angiogenesis vs microdrill-only (P = 0.049), an effect enhanced by IIa. Chitosan implant suppressed strong Col-I, Col-II, and GAG accumulation that occurred spontaneously in drill-only bone defects (P < 0.005) and coagulation factors did not alter this effect., Conclusions: Subchondral angiogenesis is promoted by chitosan implant clearance. Chitosan implant treatment suppresses fibrocartilage scar tissue formation, and promotes bone remodeling, which allows more blood vessel migration and woven bone repair towards the cartilage lesion area., (Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Factor (F)VII deficiency is an autosomal recessive disorder for which a replacement therapy is not universally available; recombinant FVIIa has been utilized as a therapeutic substitute. As FVII competes with FVIIa for binding to tissue factor in initiating the extrinsic pathway of blood coagulation, a lower dose of FVIIa replacement in cross-reacting material-negative (CRM-) individuals can achieve hemostasis. Three coagulation models (computational, synthetic and in vitro whole blood) were used to predict the FVIIa levels needed to provide apparent hemostasis in a non-bleeding state. Our whole blood results show that a 'normalized' coagulation profile for FVII-deficient individuals has an initiation phase that ends at 5.8 +/- 0.5 min (clot time) and the propagation phase of thrombin generation (thrombin-antithrombin III) yields a maximum concentration of 380 +/- 29 nmol L(-1). When CRM- FVII-deficient subjects were infused with a prophylactic dose of 23 micro g kg(-1) of recombinant FVIIa, 6-8 h postinfusion resulted in a comparable normalized whole blood profile. This FVIIa concentration (0.3-0.7 nmol L(-1)/equivalent dose: 0.8-1.8 micro g kg(-1)) is approximately 1/10 that currently used in treating FVII-deficient individuals and suggests that therapies should be altered relative to the concentration of the FVII zymogen.

The Quebec platelet disorder (QPD) is an autosomal dominant platelet disorder associated with delayed bleeding and alpha-granule protein degradation. The degradation of alpha-granule, but not plasma, fibrinogen in patients with the QPD led to the investigation of their platelets for a protease defect. Unlike normal platelets, QPD platelets contained large amounts of fibrinolytic serine proteases that had properties of plasminogen activators. Western blot analysis, zymography, and immunodepletion experiments indicated this was because QPD platelets contained large amounts of urokinase-type plasminogen activator (u-PA) within a secretory compartment. u-PA antigen was not increased in all QPD plasmas, whereas it was increased more than 100-fold in QPD platelets (P <.00009), which contained increased u-PA messenger RNA. Although QPD platelets contained 2-fold more plasminogen activator inhibitor 1 (PAI-1) (P <.0008) and 100-fold greater u-PA-PAI-1 complexes (P <.0002) than normal platelets, they contained excess u-PA activity, predominantly in the form of two chain (tcu-PA), which required additional PAI-1 for full inhibition. There was associated proteolysis of plasminogen in QPD platelets, to forms that comigrated with plasmin. When similar amounts of tcu-PA were incubated with normal platelet secretory proteins, many alpha-granule proteins were proteolyzed to forms that resembled degraded QPD platelet proteins. These data implicate u-PA in the pathogenesis of alpha-granule protein degradation in the QPD. Although patients with the QPD have normal to increased u-PA levels in their plasma, without evidence of systemic fibrinogenolysis, their increased platelet u-PA could contribute to bleeding by accelerating fibrinolysis within the hemostatic plug. QPD is the only inherited bleeding disorder in humans known to be associated with increased u-PA.

We recently described a Quebec family with an autosomal dominant bleeding disorder characterized by mildly reduced-low normal platelet counts, an epinephrine aggregation defect, multimerin deficiency, and proteolytic degradation of several, soluble alpha-granular proteins. Similar clinical features led us to investigate a second family with an unexplained, autosomal dominant bleeding disorder. The affected individuals had reduced to normal platelet counts, absent platelet aggregation with epinephrine, and multimerin deficiency. Their platelet alpha-granular proteins factor V, thrombospondin, von Willebrand factor, fibrinogen, fibronectin, osteonectin, and P-selectin were proteolyzed and comigrated with the degradation products found in patients from the other family. However, their platelet albumin, IgG, external membrane glycoproteins, CD63 (a lysosomal and dense granular protein), calpain, and plasma von Willebrand factor were normal, indicating restriction in the proteins proteolyzed. Electron microscopy studies indicated preserved alpha-granular ultrastructure, despite degradation of soluble and membrane alpha-granular proteins. Immunoelectron microscopy studies of the patients' platelets indicated that fibrinogen, von Willebrand factor, P-selectin, multimerin, and factor V were within alpha-granules, with normal to reduced labeling for these proteins. Pathologic proteolysis of alpha-granular contents, rather than a defect in targeting proteins to alpha-granules, may be the cause of the protein degradation in the Quebec platelet disorder.

Background: The purpose of our review was to develop simple clinical recommendations to reduce the need for allogeneic blood transfusions in children undergoing cardiac operations., Methods: The literature on hemostasis as it relates to children, cardiac disease in children, and pediatric heart surgery was reviewed. We also reexamined the efficacy of several strategies in this patient population: on-site monitoring of coagulation, transfusion of fresh whole blood, and administration of desmopressin, epsilon-aminocaproic acid, or aprotinin., Results: Children with heart disease may present with preoperative thrombocytopenia, reduced platelet aggregation, and a decreased level of von Willebrand factor. Infants less than 6 months of age show a significant dilution of coagulation factors and decreased platelet counts during cardiopulmonary bypass. Fresh whole blood reduces blood loss in children younger than 2 years undergoing complex operations. Desmopressin does not reduce bleeding, whereas on-site monitoring, synthetic antifibrinolytics, and aprotinin require further evaluation in pediatric cardiac surgical patients., Conclusions: The use of fresh whole blood to reduce blood loss in children younger than 2 years undergoing complex heart operations is recommended. Therapy for excessive bleeding after cardiopulmonary bypass will vary according to the patient's age, platelet count, and activated partial thromboplastin and prothrombin times.

Multimerin is a massive soluble, multimeric protein found in platelets and endothelial cells. Recent studies identified multimerin as a specific coagulation factor V binding protein, complexed with platelet, but not plasma, factor V. These findings led us to investigate individuals with inherited factor V deficiencies for possible multimerin abnormalities. Platelet proteins were evaluated using immunoassays, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, immunoprecipitation, and direct binding studies. Patients with factor V Quebec, a disorder with abnormal platelet factor V, had a quantitative deficiency in multimerin (n = 11 tested; mean, 12.5%; range, 5% to 27% of the normal pool; normal range, 45% to 214%) with a normal multimer pattern. Quantitative and qualitative abnormalities were detected in their platelet factor V. An unrelated patient who was deficient in platelet and plasma factor V had normal platelet multimerin. The levels of platelet beta-thromboglobulin, von Willebrand factor, thrombospondin, and fibrinogen antigen were normal in the factor V Quebec patients. However, proteins with abnormal mobility were detected in their platelet lysate and releasate, and their platelet thrombospondin, von Willebrand factor, and fibrinogen showed evidence of proteolytic degradation. Platelet counts of the factor V Quebec patients ranged from mildly thrombocytopenic to low normal (mean, 159 x 10(9)/L; range, 104 to 198 x 10(9)/L). In addition, their platelets failed to aggregate in response to 6 to 10 micromol/L epinephrine despite normal numbers of platelet alpha 2-adrenergic receptors. These data indicate that patients with factor V Quebec have an inherited bleeding disorder distinct from other platelet disorders and associated with multiple abnormalities, including multimerin deficiency, abnormal platelet factor V, thrombospondin, von Willebrand factor, and fibrinogen, and an epinephrine aggregation defect.

Factor V Quebec has been described as a bleeding disorder that exhibits an autosomal dominant inheritance pattern and presents severe bleeding after trauma. Two members of a fourth-generation (IV.13 and IV.15) Canadian family have been studied in detail and are the subject of this report. Their clinical presentations and histories have been described previously (Tracy et al: J Clin Invest 74:1221, 1984). Persistent abnormalities include mild thrombocytopenia and defective platelet factor V. Plasma factor V is present at near normal concentration and is fully functional. Thus, the bleeding diathesis appears to reflect the absence of platelet factor V activity. The recent report (Hayward et al: Blood 84:110a, 1994 [suppl, abstr]) of multimerin deficiency in these individuals led us to reevaluate these patients. Western blot analyses of platelet lysates developed with a variety of monoclonal antibodies show that the alpha-granule proteins, fibrinogen, von Willebrand factor, factor V and osteonectin are decreased in concentration and significantly degraded in the platelets of these patients. Thrombospondin, while not degraded, is substantially decreased. In contrast, platelet factor 4 and beta-thromboglobulin do not appear to be affected. These observations suggest that the alpha-granules are correctly assembled but the contents are subsequently subjected to proteolytic degradation. The results indicate that factor V Quebec disorder is probably associated with a generalized defect that leads to degradation of most proteins of the alpha-granules.

Desmopressin (DDAVP) has been reported to reduce bleeding in patients undergoing spinal fusion. To evaluate its efficacy in normal patients, 30 healthy young patients (ASA physical status I or II) undergoing spinal fusion for idiopathic scoliosis were randomly allocated to receive either 100 mL of physiologic saline solution (placebo group) or DDAVP (10 micrograms/m2 of body surface area) (DDAVP group) in a prospective, double-blind trial. Intraoperative blood loss was measured by weighing sponges and suction drainage and postoperative bleeding by wound drainage. The amount of blood loss expressed as a percent of the estimated blood volume was similar in both groups during the intraoperative period (67.0% +/- 28.8% [mean +/- SD] placebo group vs 57.4% +/- 26.5% DDAVP group), the postoperative period up to 24 h (32.5% +/- 6.4% placebo group vs 31.1% +/- 10.6% DDAVP group), and both periods (94.3% +/- 29.4% placebo group vs 88.2% +/- 30.7% DDAVP group). With the dose used in our study, we conclude that DDAVP does not reduce surgical bleeding in patients undergoing spinal fusion for idiopathic scoliosis.

Infection is the leading cause of illness and death in children with leukemia. The risk of infection may change over time as regimens of therapy are modified. A review of the hospital charts of 166 infants in whom leukemia had been diagnosed between 1976 and 1980 revealed an increased number of deep fungal infections (20 v. 3) during this period in comparison with the number between 1969 and 1976 in 164 patients treated at the same hospital whose leukemia was diagnosed between 1969 and 1975. The 20 severe fungal infections between 1976 and 1980 were characterized by difficulty of diagnosis (a definite diagnosis having been made three times out of four only at autopsy), an important role of Candida but also of Aspergillus (the latter having been isolated almost as often as the former) and a grave prognosis (the mortality being very high [75%] and much above that for gram-positive septicemia [6%] and that for gram-negative septicemia [31%]). This increase in frequency of fungal infections was concurrent with the introduction of phase-1 chemotherapy, which was often responsible for prolonged neutropenia. To reduce the risk of infection in children with leukemia it appears to be essential to improve diagnostic methods and approaches to therapy.

5-Aza-2'-deoxycytidine (5-aza-dCyd) is an effective antileukemic agent. In view of the importance for an antileukemic agent to cross effectively the blood-brain-barrier, we studied the plasma and cerebrospinal fluid (CSF) pharmacokinetics of this drug in rabbits and dogs. The 5-aza-dCyd concentrations in biological fluids were determined by bioassay and high-performance liquid chromatography. 5-Aza-dCyd was administered either as an i.v. bolus or as a continuous i.v. infusion following a loading dose. Blood and CSF samples were collected at various time intervals. After an i.v. bolus, the plasma disappearance of 5-aza-dCyd was biphasic with half-lives of 5 and 43 min in rabbits and of 5 and 75 min in dogs. The apparent volume of distribution at steady state was in the order of 800 ml/kg for both species. The total plasma clearance of the drug was 15 ml/min/kg in rabbits and 9 ml/min/kg in dogs. After a 180 min i.v. infusion, 5-aza-dCyd slow disappearance half-lives were of 39 min in rabbits and of 144 min in dogs. The 5-aza-dCyd concentrations attained in the CSF were 27 and 58% of the plateau plasma concentration in rabbits and dogs, respectively. The drug disparition from the CSF followed closely the plasma profile after an i.v. infusion with a somewhat longer half-life. These results showed that 5-aza-dCyd can cross the blood-CSF barrier effectively, producing cytotoxic concentrations in the CSF when given by i.v. infusion.

A review of the hospital records of 164 children with leukemia diagnosed between January 1969 and December 1975 disclosed 51 episodes of septicemia in 43 patients; 57 infectious agents were isolated. Gram-positive bacteria were isolated as frequently as gram-negative bacteria, each type accounting for 45.6% of all the agents isolated. Only 2 of the 24 episodes of exclusively gram-positive septicemia were fatal, whereas 9 of the 23 episodes of exclusively gram-negative septicemia were fatal. The mean duration of neutropenia was 5.6 days in patients with gram-positive septicemia and 19.5 days in patients with gram-negative septicemia, a significant difference (P less than 0.01). Gram-positive septicemia was diagnosed after a mean of 5.9 days of hospitalization and gram-negative septicemia after a mean of 29.0 days, also a significant difference (P less than 0.001). In this exclusively pediatric population of leukemic patients gram-positive agents have to be considered as potential pathogens, and initial antibiotic therapy must be selected with this fact in mind.