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Biomedical subjects

Jun Teruya

Publications and source records attributed to Jun Teruya.

7 recordsLinked to original sources

Venous thrombosis associated with staphylococcal osteomyelitis in children.

BACKGROUND: Venous thrombosis (VT) in children with Staphylococcus aureus osteomyelitis occurs rarely. We describe clinical features of infections and molecular characterization of isolates of children at Texas Children's Hospital with S aureus osteomyelitis and VT. METHODS: We reviewed records and imaging studies (chest radiographs, ultrasound, computed tomography, and MRI) of 9 patients at Texas Children's Hospital with acute S aureus osteomyelitis and new onset VT between August 1999 and December 2004. Isolates were fingerprinted by pulsed-field gel electrophoresis and tested for the presence of genes encoding selective virulence factors. RESULTS: The mean age of the patients was 10.6 years. All 9 of the patients had osteomyelitis with sites of infection adjacent to the VT. The femoral and popliteal veins were most commonly affected. Two patients had VTs develop on the same side in which a central line had been in place. Four patients had chest radiographs consistent with septic emboli; inferior vena cava filters were placed in 3. Evaluation for hypercoagulable state revealed 3 patients with lupus anticoagulant, 1 with anticardiolipin IgG antibody, and 5 with no defect. Most laboratory abnormalities had resolved at follow-up. Seven patients had infections caused by methicillin-resistant S aureus belonging to the same clonal group (USA300); all were community acquired. Seven isolates carried the Panton-Valentine leukocidin (luk-S-PV and luk-F-PV) genes. CONCLUSIONS: The predominant community-acquired, methicillin-resistant S aureus clone in Houston, Texas, (USA300) may have a unique propensity to cause VT in association with osteomyelitis. Management of the venous thrombosis in this setting may be complicated by the rapid evolution of septic emboli.

Adolescent↗

A practical approach to pediatric patients referred with an abnormal coagulation profile.

CONTEXT: Workup for prolonged prothrombin time (PT) and activated partial thromboplastin time (PTT) is a frequent referral to a Hematology and Coagulation Laboratory. Although the workup should be performed in a timely and cost-effective manner, the complete laboratory assessment of the coagulation state has not been standardized. OBJECTIVE: To determine which clinical and laboratory data are most predictive of a coagulopathy and to formulate the most efficient strategy to reach a diagnosis in patients referred for abnormal coagulation profiles. DESIGN: Retrospective case review. Medical records of 251 patients referred for prolonged PT and/or PTT to our Hematology Service between June 1995 and December 2002 were reviewed. RESULTS: The study included 135 males and 116 females with a mean age of 7.0 years. A personal history of bleeding was reported in 137 patients, and a family history of bleeding was reported in 116 patients. Fifty-one patients (20%) had a coagulopathy (ie, a bleeding risk). Factors predictive of a bleeding risk were a positive family history of bleeding (P < .001) and a positive personal history of bleeding (P = .001). Of 170 patients with findings of normal PT and PTT values on repeat testing, 14 were subsequently diagnosed with a coagulopathy. Two of these patients reported no positive personal or family history of bleeding. CONCLUSIONS: Coagulopathy was identified in 20% of the children referred for abnormal PT and/or PTT. In the absence of a personal or family history of bleeding, a normal PT and/or PTT on repeat testing has a negative predictive value of more than 95%.

Blood Coagulation↗

Thromboelastographic and hemostatic characteristics in pediatric patients with sickle cell disease.

CONTEXT: Patients with sickle cell disease suffer from a variety of vaso-occlusive events that may be related to activation of the hemostatic system. Thromboelastography assesses the functionality of this system from a global standpoint and has demonstrated some utility in detecting hypercoagulable states in varied clinical settings, but it has not been systematically evaluated in patients with sickle cell disease. OBJECTIVE: To characterize the findings of thromboelastography in patients with sickle cell disease during periods of steady state and illness, to compare these results with those of healthy controls, and to correlate these profiles with other measured hemostatic parameters. DESIGN: In this cross-sectional study, we obtained thromboelastographic and other hemostatic data on specimens from 46 patients with sickle cell disease (35 with hemoglobin SS, 7 with hemoglobin SC, and 4 with hemoglobin S-beta thalassemia) and 20 healthy race-matched controls. Data were obtained from patients with sickle cell disease at baseline conditions (n = 41) and in the setting of acute illness (n = 5). RESULTS: Patients with hemoglobin SS had lower reaction time and higher angle, maximum amplitude, and coagulation index values on thromboelastography than the control group. Hemoglobin SC patients had higher angle, maximum amplitude, and coagulation index values than controls. Hemoglobin S-beta thalassemia patients showed no significant differences compared with controls. Five hemoglobin SS patients with recent or current illness demonstrated increased maximum amplitude and coagulation index compared with hemoglobin SS patients at baseline conditions. CONCLUSIONS: Patients with sickle cell disease demonstrated a significant hypercoagulable state in thromboelastography profiles, with the degree of abnormality dependent on the type of sickle cell disease and perhaps the presence of acute illness. Continued follow-up of this patient cohort, as well as further study of larger and more homogeneous patient groups, is required to adequately assess the utility of thromboelastography in predicting complications of sickle cell disease.

Adolescent↗

Antiplatelet effect of aspirin in patients with cerebrovascular disease.

BACKGROUND AND PURPOSE: Aspirin is used commonly to prevent ischemic strokes and other vascular events. Although aspirin is considered safe and effective, it has limited efficacy with a relative risk reduction of 20% to 25% for ischemic stroke. We sought to determine if aspirin as currently used is having its desired antiplatelet effects. METHODS: We ascertained patients with cerebrovascular disease who were taking only aspirin as an antiplatelet agent. Platelet function was evaluated using a platelet function analyzer (PFA-100). PFA test results were correlated with aspirin dose, formulation, and basic demographic factors. RESULTS: We ascertained 129 patients, of whom 32% were taking an enteric-coated aspirin preparation and 32% were taking low-dose (< or =162 mg/d) aspirin. For the entire cohort, 37% of patients had normal PFA-100 results, indicating normal platelet function. For the patients taking low-dose aspirin, 56% had normal PFAs compared with 28% of those taking > or =325 mg/d of aspirin, while 65% of patients taking enteric-coated aspirin had normal PFAs compared with 25% taking an uncoated preparation (P<0.01 for both comparisons). Similar results were obtained if PFA results were analyzed using mean closure times (low-dose aspirin, 183 sec; high-dose aspirin, 233 sec; enteric-coated, 173 sec; uncoated, 235 sec; P<0.01 for comparisons). Older patients and women were less likely to have a therapeutic response to aspirin, independent of aspirin dose or formulation. CONCLUSIONS: A significant proportion of patients taking low-dose aspirin or enteric-coated aspirin have normal platelet function as measured by the PFA-100 test. If these results correlate with clinical events, they have broad implications in determining how aspirin is used and monitored.

Age Factors↗

Practical issues in therapeutic apheresis.

Although therapeutic plasma exchange is known to be the most effective and efficient therapeutic modality for some disorders such as thrombotic thrombocytopenic purpura and hyperviscosity syndrome, no standard protocol of plasma exchange has been developed. A protocol based on evidence needs to be established for standard of care. It should include exchange volume, replacement fluid, frequency, and end point. Indication of plasma exchange is not always clear because prospective randomized clinical trials, especially blinded trials, are difficult to perform. The standard guideline is now available from Category 1 to Category 4 and is published by the American Association of Blood Banks and the American Society for Apheresis. Each institution should establish its own pheresis guideline and protocol for each disorder.

Blood Component Removal↗