D-Dimer Elevation at Time of Admission is Associated with Need for Ventilator Support among Pediatric Patients with COVID-19 Infection.

BACKGROUND: This study aims to determine if coagulation abnormalities at presentation are associated with clinical severity of pediatric COVID-19 infection. METHODS: We retrospectively reviewed admission coagulation studies (D-dimer, prothrombin time (PT), partial thromboplastin time with hepzyme, fibrinogen, and platelet count) with disease severity defined by need for ICU admission, ventilator support, and length of stay (LOS). RESULTS: There were 110 pediatric patients (0.5 months to 18 years) who had coagulation studies collected within 24 hours of admission. Patients who required ICU admission and ventilation support had significantly higher D-dimer and PT values at presentation compared to patients who required neither. In addition, D-dimer showed moderate correlation with LOS. CONCLUSIONS: Elevated D-dimer correlated significantly with severity of disease and LOS, while prolonged PT only correlated with disease severity. Our data suggest that D-dimer at presentation may predict a pediatric patient's need for ICU care or ventilator support.

Does rotational thromboelastometry accurately predict coagulation status in patients with lupus anticoagulant?

INTRODUCTION: Rotational thromboelastometry (ROTEM) is increasingly used as a tool for monitoring coagulation status. However, ROTEM is susceptible to misinterpretation due to particular coagulation abnormalities. Here, we report the effects of lupus anticoagulant (LA) on ROTEM. METHODS: A prospective observational analysis was performed on 16 children with prior studies indicating the presence of LA or antiphospholipid antibodies. ROTEM analysis was performed, and samples were further analyzed by adding phospholipids (PL) to repeat ROTEM analysis if clotting time (CT) abnormalities were discovered with comparison to ROTEM using an equal volume of isotonic saline. Prothrombin time (PT), activated partial thromboplastin time (APTT), dilute Russell's viper venom test (DRVVT), hexagonal phase phospholipid neutralization test (StaClot LA), and factor II activity studies were additionally performed. RESULTS: Eighteen samples were analyzed by ROTEM. Prolonged CT on INTEM and EXTEM was observed for 11 samples. Samples with CT prolongation had high DRVVT ratios and prolonged APTT. Further, the addition of PL partially reversed this effect, demonstrating PL-dependent inhibition as the cause of CT prolongation. No factor II deficiencies were identified, excluding LA hypoprothrombinemia syndrome as a cause of these findings. CONCLUSION: Strongly positive LA can prolong the CT on ROTEM studies and lead to erroneous conclusions regarding coagulation status in this patient population.

Evaluating the impact of the ABO blood group on the clinical outcome of thrombotic thrombocytopenic purpura associated with severe ADAMTS13 deficiency.

BACKGROUND AND OBJECTIVES: Thrombotic thrombocytopenic purpura (TTP) is caused by the decrease of ADAMTS13, leading to the accumulation of ultra large von Willebrand factor (ULVWF). It was proposed that the distribution of blood group O among TTP patients may be potentially lower than expected because of the lower levels of VWF. The aim of this study was to explore the relationship between various blood groups and the clinical outcome in TTP. MATERIALS AND METHODS: Thirty-three patients with TTP with severe ADAMTS13 deficiency were studied. Data on blood group, relapse, number of plasma exchange sessions, replacement fluid and mortality were analysed. RESULTS: Mortality rate was 15·2% and it was not impacted by blood group. The distribution of group O among patients with idiopathic TTP was lower (12%) than expected (30%). Patients with blood group O required more sessions to achieve remission than did those with group B (P = 0·02). Cryo-supernatant was used in three refractory patients with group O, who failed to respond to fresh-frozen plasma and complete remission was achieved. The overall number of relapsing episodes was 7 of 33 (21·2%), and it was not impacted by blood group. CONCLUSION: Although blood group O appeared to provide protection against TTP, more sessions were required to achieve remission. Cryo-supernatant improved the clinical outcome in refractory patients with group O. Future studies may be warranted to determine whether higher baseline VWF can be a trigger for TTP, or can confer protection by competing with a newly secreted ULVWF for platelet binding.

PIVKA-II correlates with INR but not protein C or protein S concentrations in cord blood among newborns.

BACKGROUND: Protein induced by vitamin K absence (PIVKA)-II, inactive precursor of prothrombin, is elevated in vitamin K (VK) deficiency. Our aims were to find the prevalence of VK deficiency in neonates, assess the utility of international normalized ratio (INR) as a screening tool, and explore the relationship between PIVKA-II, activated partial thromboplastin time (aPTT) and VK dependent anticoagulants. METHODS: INR, aPTT, PIVKA-II, and proteins C and S activities were measured in neonatal cord blood prior to VK administration. RESULTS: We found 45% of neonates had subclinical VK deficiency based on PIVKA-II levels and 7% based on INR. Receiver operating characteristic (ROC) analysis assessed the utility of INR in detecting >4 ng/mL of PIVKA-II and ROC of the area under the curve was 0.70 (95% CI 0.46-0.92, p = 0.07). Proteins C and S activities were normal for age and did not correlate with PIVKA-II [(r = 0.40, p = 0.14) and (r = 0.29, p = 0.29), respectively]. There was no association between aPTT and PIVKA-II (p = 0.83). CONCLUSION: PIVKA-II seems to be a sensitive indicator of mild VK deficiency. Further studies are needed to investigate the lack of relationship between PIVKA-II and functional protein C or S levels.

Platelet function defects in adolescents with heavy menstrual bleeding.

Platelet function defects (PFD) are reported to occur frequently in adult women with heavy menstrual bleeding (HMB). Few studies on adolescent HMB report varying incidence rates (2-44%) for PFD. We reviewed our institutional experience in detecting and managing PFD in adolescent HMB. Postmenarchial girls and adolescents with HMB seen at our institution undergo a comprehensive bleeding disorder work-up by paediatric haematology and paediatric gynaecology providers. Whole blood platelet aggregometry (WBPA) is performed as a second tier test after excluding thrombocytopaenia, coagulation factor deficiencies and Von Willebrand disease (VWD). We retrospectively reviewed the medical records of adolescents with HMB seen between June 2009 and November 2010, as approved by the Institutional Review Board. Patient demographics, clinical features, laboratory results, therapy details and patient outcome information were analysed. Overall, 114 postmenarchial girls and adolescents with HMB were evaluated; 68 patients (59%) had WBPA study performed. Nineteen patients (28%) had at least one aggregation or secretion defect; 12 (18%) had two or more such defects. Treatment included hormonal therapy (13/19; 68%), antifibrinolytic agents (8/19; 42%) and intra-nasal DDAVP (3/19; 16%). Thirteen patients (81%) had improved outcome (median follow-up--15.6 months; range of 1-66 months). In this study, PFD were identified in nearly one-third of girls with HMB, with the majority of these having two or more defects as identified by WBPA. Further prospective studies are needed to better define the prevalence and address appropriate management of HMB and other bleeding complications of PFD in adolescents.

Low prevalence and assay discordance of "aspirin resistance" in children.

BACKGROUND: Although "aspirin resistance" (AR-inadequate platelet inhibition as suggested by in vitro testing of aspirin-treated patients) has been widely studied in adults and linked to increased risk of adverse outcomes, its prevalence and clinical significance are largely unknown in children. PROCEDURE: To determine AR prevalence in children and its relationship to assay methodology, we undertook a cross-sectional study of 44 children (1-17 years, 24 male) on aspirin for various indications and considered three published definitions of AR in adults: platelet aggregation >/=70% to 10 microM adenosine diphosphate and >/=20% to 0.5 mg/ml arachidonic acid (AA), normal PFA-100(R) closure time and elevated urinary 11-dehydro thromboxane B(2) (11dhTxB(2)) concentration. RESULTS: Six subjects exhibited AR according to at least one of the criteria (5 by PFA-100(R), 1 by aggregometry and 11dhTxB(2) criteria); nearly all subjects had low levels of 11dhTxB(2) compared with controls. Subjects studied prior to therapy showed pronounced changes in AR parameters after aspirin dosing (e.g., mean aggregation to AA decreased from 82% to 6%, P < 0.001), confirming an aspirin effect. Subjects with AR did not differ from aspirin responsive subjects in terms of age, race, platelet count, or aspirin dose, indication or therapy duration. There was minimal correlation between assays. CONCLUSIONS: In this initial prevalence study of a clinically diverse group of pediatric patients, frequencies of AR were assay-dependent; however, the prevalence of true AR is likely low in children (2.3%; 95% CI 0.1-10.7%), in agreement with adult studies. To better define the clinical relevance of AR in children, multicenter, prospective cohort studies are imperative.

Questionable efficacy of plasma exchange for thrombotic thrombocytopenic purpura after bone marrow transplantation.

Thrombotic thrombocytopenic purpura (TTP) after bone marrow transplantation (BMT) is an uncommon complication presumably associated with extensive endothelial cell damage due to Cyclosporine, total body irradiation, or other drugs. While the majority of patients with primary TTP, which is considered to be an autoimmune process, respond to plasma exchange, TTP after BMT has a very poor prognosis. A total of 7 patients out of 307 patients who underwent BMT were diagnosed with TTP during 1989-1999. The diagnosis of TTP was made based on thrombocytopenia and microhemangiopathic hemolytic anemia characterized by an elevated LDH and the presence of schistocytes on the peripheral blood smear. Five patients were treated with plasma exchange (PE) using fresh frozen plasma and/or cryoprecipitate poor plasma as replacement fluid. One patient was treated using a protein A column. One patient did not receive plasma exchange because the 125 patient was clinically stable and was discharged. It was hard to assess the efficacy of PE due to the multiplicity of the patients' clinical condition and laboratory data. At least 4 patients did not respond to PE and 2 patients were not able to be evaluated due to multi organ failure. However, all patients died. It is not clear at this moment if PE for patients with TTP after BMT is truly beneficial.

Management of factor XI inhibitor for cardiac intervention: successful treatment with immunosuppressive therapy and plasma exchange.

Two cases with congenital homozygous factor XI deficiency developed a factor XI inhibitor following repeated plasma transfusions. Case 1 was given cyclophosphamide, intravenous immunoglobulin, and steroids. The factor XI inhibitor disappeared on day 103 and cardiac catheterization was performed without complications after giving fresh frozen plasma. Case 2 was effectively managed by plasma exchange for cardiac catheterization and surgery. However, after five plasma exchange procedures, the same plasma volume exchange was not effective in shortening the activated partial thromboplastin time (APTT). A significant heparin rebound occurred 4 h after heparin neutralization with protamine sulphate for which the patient needed to have a blood clot evacuated from around the heart.

Phyllodes Tumor of the Breast with a Grossly Malignant Appearance: A Case Report.

A huge phyllodes tumor of the breast that appeared grossly malignant in a 43-year-old woman is described. The patient suffered from a large breast tumor thatsuddenly increased in size over 5 months to occupy the entire breast. The tumorwas hard, ulcerated and 20 cm in greatest diameter. Diagnostic imaging(US, CT and MRI)demonstrated a circumscribed mass with a large cystic cavity. She underwent total mastectomy under a diagnosis of malignant breast tumor. Grossly, the cut surface of the tumor showed a large cystic cavity surrounding a fleshy, hemorrhagic and necrotic mass with a lobulared or trabeculared appearance. Unexpectedly, benign phyllodes tumor(PT)without any stromal overgrowth was diagnosed histologically. She has been doing well since total mastectomy. In our case and in many other reported cases, PT does not show any distinctive correlation between pathologic findings and tumor behavior. Thus wide local excision is the preferred initial treatment for PT.

Colonization of skin by Helcococcus kunzii.

In order to investigate the role of Helcococcus kunzii as a colonizer of skin and as a possible participant in diabetic foot ulcers, we used a selective medium to culture both lower- and upper-extremity skin from a study group of podiatry patients (60 diabetics and 60 nondiabetics) and a control group of 50 healthy volunteers. Although differences in colonization were not statistically significant, a trend toward higher colonization rates in the group of podiatry patients was noted. H. kunzii appears to preferentially colonize the skin of the feet, and while its pathogenic role in diabetic foot ulcers is difficult to establish, it may be a previously unrecognized component of the polymicrobial flora characteristically isolated from patients with these infections.

Therapy for paraneoplastic neurologic syndromes in six patients with protein A column immunoadsorption.

BACKGROUND: Paraneoplastic neurologic syndromes, although rare, cause significant morbidity and mortality. They are thought to be immunologically mediated, but to date those involving the central nervous system (CNS) have not been particularly responsive to immunologic therapy. The use of the novel immunomodulator, protein A immunoadsorption, was explored to address this question. METHODS: Six patients with neurologic paraneoplastic syndromes were treated with this technique, using the "off line" method. Two hundred fifty ml of plasma was perfused through a column containing protein A covalently attached to a silica matrix. The plasma was then returned to the patient. RESULTS: Five of the patients responded to the therapy, with complete and durable responses in three patients with opsoclonus-myoclonus, objective, though transient, improvement in one patient with paraneoplastic brainstem encephalitis associated with a Merkel cell tumor, and stabilization and partial improvement in one patient with paraneoplastic limbic encephalitis. The patient without response developed a cutaneous vasculitis after the second treatment, and therapy was discontinued. CONCLUSIONS: This therapy appears beneficial for a number of paraneoplastic syndromes, most dramatically in the opsoclonus/myoclonus syndrome.

Mode of transport of fatty acid to endothelial cells influences intracellular fatty acid metabolism.

Fatty acids are transported to cells from a variety of different moieties in the plasma. In this study, using oleate and human umbilical vein endothelial cells, we asked whether the vehicle that delivers fatty acid to cells has an influence on its metabolism upon its incorporation into the cell. For oleate vehicles, we compared free oleate bound to albumin with oleate in low density lipoprotein (LDL) which was delipidated and reconstituted with either radiolabeled triolein or cholesteryl oleate. Using approximately physiologic concentrations of LDL and free oleate, we demonstrated by three lines of evidence unique patterns of cellular oleate metabolism for oleate delivered as triolein within LDL, for oleate delivered as cholesteryl oleate within LDL, and for oleate delivered as free oleate bound to albumin. In fact, the difference was most marked between cholesteryl oleate and triolein, even though the oleate in cholesteryl oleate and triolein was delivered in identically reconstituted LDL particles, which were presumably incorporated into the cells and degraded in lysosomes in a similar fashion. First, we demonstrated that oleate delivered as free oleate or as triolein in reconstituted LDL was desaturated and elongated to fatty acid metabolites, but cholesteryl oleate in reconstituted LDL was not similarly metabolized. The elongated and desaturated metabolites of oleate were preferentially esterified in cellular triglyceride when oleate was delivered as free oleate, but they were preferentially esterified in phospholipids when oleate was delivered as triolein in LDL. Second, we observed that there was a difference in the distribution of oleate among phospholipids when oleate was delivered as cholesteryl oleate in reconstituted LDL versus triolein in reconstituted LDL. When the oleate was delivered as triolein in reconstituted LDL, there was greater esterification in diacyl phosphatidylethanolamine, in phosphatidylserine, and in phosphatidylinositol. When oleate was delivered as cholesteryl oleate in reconstituted LDL, there was greater esterification in diacyl phosphatidylcholine. Third, there was a marked preference for oleate delivered from triolein in LDL over cholesteryl oleate in LDL for esterification into the sn-1 position of plasmalogens as a vinyl ether-linked fatty acid. These data indicate that mode of transport of fatty acid to cells influences fatty acid metabolism upon its incorporation into the cell, even when the fatty acid is delivered from the core of the same lipoprotein.

Ubiquinone biosynthesis in Saccharomyces cerevisiae. Isolation and sequence of COQ3, the 3,4-dihydroxy-5-hexaprenylbenzoate methyltransferase gene.

Ubiquinone (or coenzyme Q) is a lipid component of the respiratory chain in the inner mitochondrial membrane, in which it functions in electron transport. Recent reports show that ubiquinone and ubiquinone biosynthetic enzymes are present in both mitochondrial and nonmitochondrial membranes of cells (Kalen, A., Appelkvist, E.-L., Chojnacki, T., and Dallner, G. (1990) J. Biol. Chem. 265, 1158-1164) although the functions that ubiquinone may play outside of the mitochondrion are not understood. To study coenzyme Q synthesis and function we cloned the 3,4-dihydroxy-5-hexaprenylbenzoate (DHHB) methyltransferase gene by functional complementation of a yeast coenzyme Q mutant strain, defective in the COQ3 gene (Tzagoloff, A., and Dieckmann, C. L. (1990) Microbiol. Rev. 54, 211-225). This gene restores both coenzyme Q synthesis in the mutant strain and the ability to grow on media containing glycerol, a nonfermentable substrate. A one-step in situ gene replacement with the cloned DHHB methyltransferase DNA directs integration to the yeast COQ3 locus on chromosome XV of Saccharomyces cerevisiae, establishing that the COQ3 locus encodes the DHHB methyltransferase structural gene. The predicted amino acid sequence of the yeast DHHB methyltransferase contains a methyltransferase consensus sequence and shows a 40% identity with an open reading frame of Escherichia coli, the gyrA5' hypothetical protein. This open reading frame is adjacent to the gyrA gene and close to the mapped location of the ubiG gene at 48 min on the E. coli chromosome. These results suggest that the E. coli gyrA5' open reading frame encodes a methyltransferase and may correspond to the ubiG gene, which is required for ubiquinone biosynthesis.

Testis-specific transcripts of rat farnesyl pyrophosphate synthetase are developmentally regulated and localized to haploid germ cells.

A rat farnesyl pyrophosphate (FPP) synthetase cDNA was used to study the expression of FPP synthetase mRNA levels during spermatogenesis in the rat. RNA blot analysis showed an increase in the level of FPP synthetase transcripts during postnatal development of rat testes. The increase is due to the appearance of longer testis-specific FPP synthetase transcripts as assayed by primer extension mapping. In situ hybridization analysis of adult rat testis sections with an FPP synthetase antisense probe showed that FPP synthetase mRNA levels are greatly enriched in the haploid round spermatidis at stages 7 to 8 of the seminiferous epithelium. These results show that FPP synthetase transcripts in testis are expressed at high levels in haploid male germ cells in a stage-specific manner.