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Biomedical subjects

M J Manco-Johnson

Publications and source records attributed to M J Manco-Johnson.

At least 19 recordsLinked to original sources
PubMed2007

Preanalytical conditions that affect coagulation testing, including hormonal status and therapy.

Preanalytical conditions, be they due to the individual's physiologic state or to exogenous factors, can affect coagulation factors, in either a transient or a persistent manner, and need to be considered in laboratory testing. These conditions include physical and mental stress, diurnal variation, hormone levels and posture at the time of blood drawing. While testing of these factors has not been exhaustive and some results are conflicting, guidelines for testing conditions can be given.

Anticoagulants↗
PubMed2007

The Colorado Haemophilia Paediatric Joint Physical Examination Scale: normal values and interrater reliability.

Persons with haemophilia often experience their first joint haemorrhage in early childhood. Recurrent bleeding into a joint may lead to significant morbidity, specifically haemophilic arthropathy. Early identification of the onset and progression of joint damage is critical to preserving joint structure and function. Physical examination is the most feasible approach to monitor joint health. Our group developed the Colorado Haemophilia Paediatric Joint Physical Examination Scale to identify earlier signs of joint degeneration and incorporate developmentally appropriate tasks for assessing joint function in young children. This study's objectives were to establish normal ranges for this scale and assess interrater reliability. The ankles, knees and elbows of 72 healthy boys aged 1 through 7 years were evaluated by a physical therapist to establish normal ranges. Exactly 10 boys in each age category from 2 to 7 years were evaluated by a second physical therapist to determine interrater reliability. The original scale was modified to account for the finding that mild angulation in the weight-bearing joints is developmentally normal. The interrater reliability of the scale ranged from fair to good, underscoring the need for physical therapists to have specific training in the orthopaedic assessment of very young children and the measurement error inherent in the goniometer. Modifications to axial alignment scoring will allow the scale to distinguish healthy joints from those suffering frequent haemarthroses.

Ankle Joint↗
PubMed2006

A patient satisfaction survey for haemophilia treatment centres.

The importance of patient satisfaction has continued to grow such that patient satisfaction is now viewed as a vital component of health-care delivery. This is evidenced by the expanding body of research in the area and the use of measures of patient satisfaction as indicators of health-care quality. The value of patient satisfaction is particularly apparent in the setting of chronic disease where medical care utilization is high, compliance with therapy is critical and the patient-provider relationship is often long-term. Although several validated tools exist to quantify general measures of patient satisfaction, there is a recognized need for disease-specific instruments. Not only are there issues that are unique to haemophilia, but many patients receive care via a specialized comprehensive clinic model. The authors were unaware of an instrument that could adequately address patient satisfaction issues specific to haemophilia; thus, they undertook to develop one. The patient satisfaction survey presented here contains fixed-choice, Likert-scale and open-ended questions adapted from previously validated questionnaires. Assessment of face validity and internal consistency indicate that the survey is measuring one underlying construct - patient satisfaction. Information acquired through this survey will provide a quantitative assessment of patient satisfaction within a clinic population of persons with bleeding disorders and could be used to guide decisions regarding provision of health-care services.

Adolescent↗
PubMed2006

Recent developments in clinimetric instruments.

Assessment of impairment and function is essential in order to monitor joint status and evaluate therapeutic interventions in patients with haemophilia. The improvements in the treatment of haemophilia have required the development of more sensitive tools to detect the more minor dysfunctions that may now be apparent. This paper outlines some of the recent developments in this field. The Haemophilia Joint Health Score (HJHS) provides a systematic and robust measure of joint impairment. The MRI Scoring System has been designed to provide a comprehensive scoring system combining both progressive and additive scales. The Functional Independence Score for Haemophilia (FISH) has been developed to assess performance of functional activities and can be used in conjunction with the Haemophilia Activities List (HAL) which provides a self report measure of function. It is recommended that both measures are evaluated as these tools measure different constructs. Further refinement and testing of the psychometric properties of all of these tools is in progress. More widespread use of these tools will enable the sharing of data across the world so promoting best practice and ultimately enhancing patient care.

Activities of Daily Living↗
PubMed2006

Influence of factor VIII on overall coagulability and fibrinolytic potential of haemophilic plasma as measured by global assay: monitoring in haemophilia A.

The objectives of the present study were to evaluate the analytical sensitivity of the recently developed Clot Formation and Lysis (CloFAL) global assay for factor VIII (FVIII) deficiency, both in vitro and ex vivo, to determine whether this global assay is influenced by FVIII inhibitors, and to investigate the coagulative response to FVIII replacement in haemophilia A patients using the CloFAL assay in comparison with FVIII activity. Among adults and children alike, the CloFAL assay coagulation index (CI) was significantly decreased in FVIII-deficient vs. healthy subjects (adults median CI: 2% vs. 94% respectively; children median CI: 3% vs. 63%; P < 0.001 for each), and correlated significantly with activated partial thromboplastin time-based FVIII activity across all individuals (r = 0.78; P < 0.001). The CloFAL assay was analytically sensitive to deficient FVIII activity and also influenced by the presence of von Willebrand factor. Severe haemophilia A patients without inhibitory antibodies to FVIII showed considerable heterogeneity in CloFAL assay waveforms, despite a uniformly diminished CI of 0-1%. During FVIII infusion half-life studies in patients with severe haemophilia A, the CloFAL assay demonstrated a marked rise in coagulability 30 min following infusion, with progressive decrease in coagulability towards baseline over the ensuing 48-h period. In each case, the profile of coagulative response to FVIII infusion as determined by CloFAL assay CI differed qualitatively from that measured by FVIII activity. These findings indicate that the CloFAL assay may be useful as an adjunctive test to FVIII activity measurements in the therapeutic monitoring of haemophilia A.

Adolescent↗
PubMed2005

Development of hemostasis in the fetus.

The fetal hemostatic system is unique in many respects. Many coagulation proteins are expressed early in embryonic development and play roles outside of coagulation in cell proliferation and differentiation. Coagulation mRNA and protein can be detected within hepatic and endothelial cells within the first month of gestation and in fetal plasma during the third month. However, development of levels of most coagulation proteins is halted from mid-gestation until shortly before term onset of labor. The reason for this developmental arrest in plasma protein levels is unknown. The fetus demonstrates an unique balance of procoagulant, anticoagulant and fibrinolytic proteins concentrations which persists for several months postnatally. Fetal coagulation proteins are identical to adult proteins in structure and function with a few notable exceptions. Platelets are expressed early in fetal development and platelet concentrations are within the adult range by mid-gestation. Functional differences can be detected in fetal platelet function but rarely cause bleeding in the healthy fetus and newborn infant. Hemostasis in the fetus and newborn infants is functionally intact and spontaneous bleeding or clotting is rare. However, the neonatal hemostatic system appears to lack reserve capacity, and bleeding and clotting complications are common in the stressed infant, particularly the sick preterm infant.

Blood Coagulation Factors↗
PubMed2004

Consensus recommendations for use of central venous access devices in haemophilia.

Venous access is essential for delivery of haemophilia factor concentrate. Wherever possible, peripheral veins remain the route of choice, and the use of central venous access devices (CVADs) should be limited to cases of clear need in patients with caregivers able to exercise diligence in CVAD care and should continue no longer than necessary. CVADs are of recognized value for repeated administration of coagulation factors in haemophilia, particularly for prophylaxis and immune tolerance therapy and in young children. Evidence to guide best practices has been fragmentary, and standardized methods for CVAD usage have yet to be established. We have developed management recommendations based upon available published evidence as well as extensive clinical experience. These recommendations address patient and CVAD selection; CVAD placement, care and removal; caregiver/patient guidance; and complications, including infection and thrombosis. In the absence of inhibitors, ports are recommended, primarily because of fewer associated infections than with external catheters. For patients with inhibitors, ports also appear to be associated with fewer infections. Infection is the most frequent complication, and recommendations to prevent and treat infections are supported by extensive clinical data and experience. Strict adherence to handwashing and aseptic technique are essential elements of catheter care. Evidence-based data regarding the detection and treatment of CVAD-related thrombotic complications are limited. Caregiver education is an integral part of CVAD use and the procedural practices of users should be regularly re-assessed. These recommendations provide a basis for sound current CVAD practice and are expected to undergo further refinements as new evidence is compiled and clinical experience is gained.

Catheterization, Central Venous↗
PubMed2004

Physical therapy and imaging outcome measures in a haemophilia population treated with factor prophylaxis: current status and future directions.

Routine infusions of factor VIII to prevent bleeding, known as prophylaxis, and other intensive therapies are being more broadly applied to patients with haemophilia. These therapies differ widely in replacement product usage, cost, frequency of venous access and parental effort. In order to address residual issues relating to recommendations, implementation, and evaluations of prophylaxis therapy in persons with haemophila, a multinational working group was formed and called the International Prophylaxis Study Group (IPSG). The group was comprised of haemophilia treaters actively involved in studies of prophylaxis from North America and Europe. Two expert committees, the Physical Therapy (PT) Working Group and the Magnetic Resonance Imaging (MRI) Working Group were organized to critically assess existing tools for assessment of joint outcome. These two committees independently concluded that the WFH Physical Examination Scale (WFH PE Scale) and the WFH X-ray Scale (WFH XR Scale) were inadequately sensitive to detect early changes in joints. New scales were developed based on suggested modifications of the existing scales and called the Haemophilia Joint Health Score (HJHS) and the International MRI Scales. The new scales were piloted. Concordance was measured by the intra-class correlation coefficient of variation. Reliability of the HJHS was excellent with an inter-observer co-efficient of 0.83 and a test-retest value of 0.89. The MRI study was conducted using both Denver and European scoring approaches; inter-reader reliability using the two approaches was 0.88 and 0.87; test-retest reliability was 0.92 and 0.93. These new PT and MRI scales promise to improve outcome assessment in children on early preventive treatment regimens.

Hemophilia A↗
PubMed2004

Severe hemophilia A due to a 1.3 kb factor VIII gene deletion including exon 24: homologous recombination between 41 bp within an Alu repeat sequence in introns 23 and 24.

Partial or complete factor (F)VIII gene deletions are found in about 5% of families with severe hemophilia A. Relatively few deletions have been well characterized and, of these, recombination occurred between either common repeat elements or non-homologous sequences. In evaluating a family with severe hemophilia A, an exon 24 deletion was suspected when no fragment was obtained on attempted PCR amplifications. A combination of the 5' primer of exon 23 and the 3' primer of exon 25 fragments was used with prolonged extension times to amplify a normal 2.9 kb fragment that included exons 23 through 25; the patient's amplified product was 1.6 kb indicating a 1.3 kb deletion. A mixture of normal and patient DNA showed both sized fragments as did that from an obligate carrier. Carrier detection was applied to two women at risk; one was and one was not a carrier. Sequencing the proband's 1.6 kb fragment revealed that a 1328 bp deletion occurred between homologous sequences of 287 and 285 bp in introns 23 and 24, respectively; these share 85% identity. Blast nucleotide search revealed that these represent Alu elements. Comparison with an alignment of each of the two homologous sequences further localized recombination to a 41-bp segment. However, a simple recombination event would not account for the proband's sequence. The most likely explanation is that the homologous recombination was accompanied by incomplete mismatch repair.

Alu Elements↗
PubMed2003

Primary antiphospholipid antibody syndrome and cardiac involvement in a child.

We report a case of polyvalvar disease and recurrent thrombosis in a 2-year-old boy due to primary antiphospholipid antibody syndrome. His diagnosis was delayed, and he was treated for other diagnoses, including culture-negative endocarditis. Primary antiphospholipid antibody syndrome is rarely discussed in the pediatric cardiology literature, and this case highlights the need for early diagnosis to prevent recurrent valve dysfunction and thrombosis.

Antibodies, Anticardiolipin↗
PubMed2003

A survey of factor prophylaxis in boys with haemophilia followed in North American haemophilia treatment centres.

A survey was conducted in 2002 to determine the pattern of factor prophylaxis use in boys or=45 weeks per year, was significantly higher for haemophilia A vs. haemophilia B cases (51% vs. 32%, P< 0.0001), and for boys with severe haemophilia A living in Canada vs. the USA (77% vs. 47%, P< 0.0001). Use of full-dose prophylaxis, defined as the infusion of 25-40 IU kg(-1) of factor VIII on alternate days (minimum three times per week) or 25-40 IU kg(-1) of factor IX twice weekly, was similar for boys <or=5 years of age in both Canada and the USA (30% and 33% haemophilia A and 35% and 13% haemophilia B). Reasons for initiating prophylaxis included a history of joint bleeding (88%) and age <or=2 years (23%). For prophylaxis triggered by joint bleeding, 38% of haemophilia treatment centres indicated that they would initiate prophylaxis after the first joint bleed and 66% after a history of target joint bleeding, defined most frequently as 2-4 bleeds over a 3-6 consecutive month period. A central venous line was used to ensure easy venous access for full-dose prophylaxis therapy in 80% of boys <or=5 years of age. These data offer a basis for projecting long-term factor concentrate needs for persons with haemophilia living in North America.

Adolescent↗
PubMed2003

North American prophylaxis studies for persons with severe haemophilia: background, rationale and design.

Arthropathy is associated with the greatest cost and morbidity to persons with haemophilia. Clinical protocols have been developed empirically to prevent or retard the development of joint disease using routine infusions of replacement factor concentrate. However, randomized clinical trials to determine optimal therapy to prevent joint disease in persons with severe haemophilia are lacking. Two clinical trials are ongoing to answer important clinical questions about the prevention of arthropathy. The first, a US randomized clinical trial, is comparing an aggressive multiple-infusion episode-based protocol to standard alternate-day prophylaxis to determine whether prevention of joint disease requires prevention of the bleeding event, per se, or can be achieved by promoting complete resolution of each bleeding event in the joint. This study included the development and validation of sensitive new physical and imaging scales to detect the earliest signs of joint disease in young children. The second, a single-arm, open-label Canadian study, is asking whether prevention of joint disease in young children can be individualized by escalating the dose and frequency of routine replacement infusions of factor concentrate based upon the clinical course of haemophilia in the affected child. Both of these studies will contribute valuable information regarding optimal therapy and will help establish evidence-based medicine for the management of severe haemophilia.

Acute Disease↗
PubMed2003

Consensus perspectives on prophylactic therapy for haemophilia: summary statement.

Participants in an international conference on prophylactic therapy for severe haemophilia developed a consensus summary of the findings and conclusions of the conference. In the consensus, participants agreed upon revised definitions for primary and secondary prophylaxis and also made recommendations concerning the need for an international system of pharmacovigilance. Considerations on starting prophylaxis, monitoring outcomes, and individualizing treatment regimens were discussed. Several research questions were identified as needing further investigation, including when to start and when to stop prophylaxis, optimal dosing and dose interval, and methods for assessment of long-term treatment effects. Such studies should include carefully defined cohorts, validated orthopaedic and quality-of-life assessment instruments, and cost-benefit analyses.

Consensus Statements as Topic↗
PubMed2001

The varicella-autoantibody syndrome.

This cross-sectional study was conducted to determine the incidence of autoantibodies to phospholipids and coagulation proteins in children with acute varicella zoster virus (VZV) infection. Study groups included children with VZV alone or complicated by purpura fulminans and/or thromboembolism. VZV naïve children and children who had VZV >1 y before sample collection formed a control group. Blood was assayed for the following: free protein S (PS), protein C, antithrombin, and prothrombin; antibody binding to these proteins; lupus anticoagulant; anticardiolipin antibody; antiphospholipid antibodies; and prothrombin fragment 1+2. Data regarding coinfections was collected. Forty-three VZV-infected children showed an increased frequency of lupus anticoagulant, anticardiolipin antibody, antiphospholipid antibodies, and autoantibodies to PS, protein C, prothrombin, and antithrombin in comparison to 52 children without acute VZV (p < 0.0001). Seventeen children with VZV and purpura fulminans and/or thromboembolism showed a statistically significant decrease in free PS, significantly increased PS IgG antibody, and significantly increased prothrombin fragment 1+2 (p < 0.0001) compared with the group without acute VZV and the group with uncomplicated VZV. Twenty-six children with uncomplicated VZV showed increased PS IgG antibody (p < 0.001) compared with the children without acute VZV. For all groups combined, elevated PS IgG antibody showed negative correlation with free PS (p < 0.0001) and positive correlation with prothrombin fragment 1+2 (p = 0.0002). Autoantibodies were transient. Transient antiphospholipid and coagulation protein autoantibodies were common with VZV infection, but were not predictive of thrombotic complications.

Adolescent↗
PubMed2000

Combined thrombolytic and anticoagulant therapy for venous thrombosis in children.

OBJECTIVES: To evaluate safety, efficacy, and outcome after combination thrombolytic and anticoagulant therapy. STUDY DESIGN: An open nonrandomized clinical protocol with prospective standardized monitoring and data collection. Children with a documented first episode of deep vein thrombosis were treated with urokinase 4400 U/kg load and per hour with unfractionated heparin at 10 U/kg/h. At 48 hours heparin infusions were increased to achieve a therapeutic level for 5 days. Children were given therapeutic warfarin for at least 3 months. Outcome was assessed at 48 hours and > or =1 year with history, physical examination, high-resolution imaging, and Doppler ultrasonography +/- impedance and photo plethysmography. RESULTS: Thirty-two children were treated. There was 1 thrombotic death, 1 nonfatal thrombus progression, and 1 pulmonary embolism. At 48 hours half of the children showed substantial clot lysis, and on follow-up these children had complete resolution and had no symptoms. Three children with poor early clot lysis had recurrent thromboemboli, pulmonary embolism, or both, 2 had limb pain and swelling, and 2 had asymptomatic swelling. Two children had minor bleeding, whereas systemic reactions were common. CONCLUSIONS: Combination therapy in children (urokinase and unfractionated heparin) was safe and efficacious. A prospective, randomized, controlled study in children is needed.

Adolescent↗
PubMed2000

Joint evaluation instruments for children and adults with haemophilia.

With the heightened interest in protocols to prevent or treat complications of haemophilia related to recurrent haemarthroses, there is a need for sensitive joint-evaluation tools. The World Federation of Haemophilia (WFH) Physical Joint Examination instrument, which was developed for persons with haemophilia worldwide, is not sensitive enough to detect early structural or functional abnormalities. Therefore, we have expanded the WFH instrument to detect more subtle abnormalities of joint structure and function, and in addition, developed a new scale specifically tailored to the dynamic growth and gait development of children. We compared the original and three new instruments in 43 children with haemophilia. The three new scales all showed better correlation with the WFH pain instrument than did the original WFH physical examination instrument (P < 0.01 for each of the new instruments vs. P > 0.05 for the WFH instrument). In addition, results of the new child physical examination instrument best conformed to a normal distribution (P=0.35) and this instrument had better overall statistical performance. This instrument should be studied further in prospective, longitudinal clinical trials of young children.

Adolescent↗