Histological validation of a type 1 diabetes clinical diagnostic model for classification of diabetes.

AIMS: Misclassification of diabetes is common due to an overlap in the clinical features of type 1 and type 2 diabetes. Combined diagnostic models incorporating clinical and biomarker information have recently been developed that can aid classification, but they have not been validated using pancreatic pathology. We evaluated a clinical diagnostic model against histologically defined type 1 diabetes. METHODS: We classified cases from the Network for Pancreatic Organ donors with Diabetes (nPOD) biobank as type 1 (n = 111) or non-type 1 (n = 42) diabetes using histopathology. Type 1 diabetes was defined by lobular loss of insulin-containing islets along with multiple insulin-deficient islets. We assessed the discriminative performance of previously described type 1 diabetes diagnostic models, based on clinical features (age at diagnosis, BMI) and biomarker data [autoantibodies, type 1 diabetes genetic risk score (T1D-GRS)], and singular features for identifying type 1 diabetes by the area under the curve of the receiver operator characteristic (AUC-ROC). RESULTS: Diagnostic models validated well against histologically defined type 1 diabetes. The model combining clinical features, islet autoantibodies and T1D-GRS was strongly discriminative of type 1 diabetes, and performed better than clinical features alone (AUC-ROC 0.97 vs. 0.95; P = 0.03). Histological classification of type 1 diabetes was concordant with serum C-peptide [median < 17 pmol/l (limit of detection) vs. 1037 pmol/l in non-type 1 diabetes; P < 0.0001]. CONCLUSIONS: Our study provides robust histological evidence that a clinical diagnostic model, combining clinical features and biomarkers, could improve diabetes classification. Our study also provides reassurance that a C-peptide-based definition of type 1 diabetes is an appropriate surrogate outcome that can be used in large clinical studies where histological definition is impossible. Parts of this study were presented in abstract form at the Network for Pancreatic Organ Donors Conference, Florida, USA, 19-22 February 2019 and Diabetes UK Professional Conference, Liverpool, UK, 6-8 March 2019.

Laboratory monitoring of haemostasis.

Peri-operative coagulation monitoring should begin with the assessment of individual bleeding risk using a standardised bleeding history before the surgical procedure. Laboratory testing should be performed if this history is abnormal or peri-operative bleeding is anticipated. This process sensitively identifies those at risk of peri-operative bleeding and therefore minimises their peri-operative risk, without costly and time-consuming population testing. There are multiple potential causes of haemostatic derangement within the peri-operative period, and an understanding of both normal haemostasis and the coagulation tests available to detect coagulopathy is required to optimise patient management. In bleeding patients, routine coagulation tests should be requested, but one should be aware of the major limitations that exist. Delay whilst waiting for these laboratory results, which, in turn, aggravates coagulopathy, bleeding, blood product requirements, length of surgery and overall morbidity and mortality.

Genetic testing in bleeding disorders.

The aim of molecular genetic analysis in families with haemophilia is to identify the causative mutation in an affected male as this provides valuable information for the patient and his relatives. For the patient, mutation identification may highlight inhibitor development risk or discrepancy between different factor VIII assays. For female relatives, knowledge of the familial mutation can facilitate carrier status determination and prenatal diagnosis. Recent advances in understanding mutations responsible for haemophilia and methods for their detection are presented. For reporting of such mutations, participation in external quality assessment ensures that essential patient and mutation details are routinely included and that pertinent information is incorporated in the interpretation.

Genetics of haemostasis.

Congenital defects of platelets or plasma proteins involved in blood coagulation generally lead to bleeding disorders. In some of these disorders, patients with a severe phenotype are prone to spontaneous bleeds with critical consequences. This situation occurs more commonly in haemophilia A and haemophilia B and to a certain extent in severe forms (type 3) of von Willebrand disease. Defects in other plasma coagulation proteins and platelet factors are relatively rare, with an incidence of ≤ 1: 1-2 million. Molecular genetic studies of the human coagulation factors, especially factors VIII and IX, have contributed to a better understanding of the biology of these genetic disorders, the accurate detection of carriers and genetic counselling, and have also fostered new therapeutic strategies. This article reviews the evolution of genetics over the last five decades as a tool for bleeding disorder investigations, the recent advances in molecular techniques that have contributed to improved genetic diagnosis of this condition, and the development and utility of proficiency testing programmes and reference materials for genetic diagnosis of bleeding disorders.

Don't be a clot: a radiologist's guide to haemostasis including novel antiplatelet and anticoagulant therapies.

Normal haemostasis relies on the complex interactions of the coagulation cascade, platelets, and the endothelium. In this review, the roles of each of these elements are described as well as common causes for their derangement. Haemostasis may be manipulated via pharmacological means and in recent years there has been a significant increase in the number of agents available for influencing haemostatic mechanisms. It is essential that radiologists are aware of these mechanisms and drugs if they are to perform image-guided procedures safely. In addition to describing the relevant pathways and drugs, practical tips are provided.

Familial and racial determinants of tumour suppressor genes promoter hypermethylation in breast tissues from healthy women.

To determine the hypermethylation status of the promoter regions of tumour suppressor genes in breast tissues from healthy women and identify the determinants of these epigenetic changes. Questionnaires and breast tissues were collected from healthy women without a history of cancer and undergoing reduction mammoplasty (N= 141). Methylation for p16(INK4), BRCA1, ERalpha and RAR-beta promoter regions from breast tissues were determined by methylation specific PCR. Associations were examined with chi-square and Fisher's exact test as well as logistic regression. All statistical tests were two-sided. p16(INK4), BRCA1, ERalpha and RAR-beta hypermethylation were identified in 31%, 17%, 9% and 0% of the women, respectively. Women with BRCA1 hypermethylation had an eight-fold increase in the risk of ERalpha hypermethylation (P= 0.007). p16(INK4) hypermethylation was present in 28% of African-Americans, but 65% in European-Americans (P= 0.02). There was an increased likelihood of p16(INK4) or BRCA1 hypermethylation for women with family history of cancer (OR 2.3; 95%CI: 1.05-4.85 and OR 5.0; 95%CI: 1.55-15.81, respectively). ERalpha hypermethylation was associated with family history of breast cancer (OR 6.6; 95%CI: 1.58-27.71). After stratification by race, p16(INK4) in European-Americans and BRCA1 hypermethylation in African-Americans were associated with family history of cancer (OR 3.8; 95%CI: 1.21-12.03 and OR 6.5; 95%CI: 1.33-31.32, respectively). Gene promoter hypermethylation was commonly found in healthy breast tissues from women without cancer, indicating that these events are frequent and early lesions. Race and family history of cancer increase the likelihood of these early events.

A review of long-term prophylaxis in the rare inherited coagulation factor deficiencies.

The rare inherited coagulation factor deficiencies (deficiencies of factors I, II, V, VII, XI, XIII, combined FV + FVII deficiency, combined deficiency of the vitamin K dependent factors and von Willebrand disease type 3) have an aggregate prevalence of approximately 1:100,000. They may cause recurrent life or function threatening haemorrhage. In this article we review the available literature on long-term prophylaxis and, where possible, make recommendations on this important area.

Recombinant factor VIIa to prevent surgical bleeding in factor XI deficiency.

Factor XI (FXI) deficiency is associated with bleeding after invasive procedures. Risks of human plasma-derived FXI replacement products include transfusion transmitted infection, thrombosis and fluid overload. This study was designed to test the hypothesis that recombinant factor VIIa (rFVIIa) is an effective haemostatic agent in patients with FXI deficiency undergoing surgery. Fourteen FXI deficient patients [five severely deficient (FXI:C <20 U dL(-1)) and nine partially deficient (FXI:C 20-70 U dL(-1)] received rFVIIa to prevent surgical bleeding during five major, four minor and six dental procedures. Minor surgical and dental procedures were covered with two doses of rFVIIa (90 microg kg(-1) i.v.), the first pre-operatively and the second 4 h postoperatively. Major surgery was covered with 90 microg kg(-1) i.v. two hourly for the first 24 h and four hourly for the second 24 h. Oral tranexamic acid was given for 7 days postoperatively. Effective haemostasis was observed in all cases and no alternative haemostatic agents or blood transfusions were required. Three adverse events were recorded; an acute cerebrovascular accident in a patient with a history of cardiovascular disease, an allergic reaction and local phlebitis. In this study, rFVIIa was an effective alternative to plasma-derived FXI replacement for the prevention of surgical bleeding in FXI deficient patients but rFVIIa may not be suitable for patients with pre-existing risk factors for thrombosis.

Guidelines for the management of patients on oral anticoagulants requiring dental surgery.

The objective of these guidelines is to provide healthcare professionals, including primary care dental practitioners, with clear guidance on the management of patients on oral anticoagulants requiring dental surgery. The guidance may not be appropriate in all cases and individual patient circumstances may dictate an alternative approach.

Severe factor X deficiency due to a homozygous mutation (Cys364Arg) that disrupts a disulphide bond in the catalytic domain.

Severe factor X deficiency (<0.01 IU mL(-1)) is a rare disorder producing a major bleeding tendency including umbilical cord, joint and intracranial haemorrhage. We present the first case of a child homozygous for a g.1177T > C missense alteration, predicted to disrupt the catalytic domain, and resulting in severe FX deficiency. The child suffered intracranial haemorrhage and now receives regular prophylaxis with a prothrombin complex concentrate. Our experience and a review of the literature suggest that optimal frequency of dosing is likely to be two or three times weekly and that the risk of thrombosis is very small.

A framework for genetic service provision for haemophilia and other inherited bleeding disorders.

This framework document offers guidance to patients, doctors, nurses, laboratory scientists, funders and hospitals on the provision of clinical and laboratory genetic services for haemophilia. With recent advances in molecular laboratory techniques it is now possible to give the vast majority of individual patients and family members very reliable genetic information. To enable these genetic data to be used for both the optimal treatment of patients with inherited bleeding disorders and for appropriate reproductive decisions in carriers, there needs to be a clear and robust framework for systematically acquiring the necessary clinical, personal, family and laboratory information upon which decisions can be made. This document provides guidance on the range and standards of clinical and laboratory genetic services which should be offered to patients and their families. Included are arrangements for genetic counselling and testing (including consent and confidentially issues), management of early pregnancy, standards for laboratory genetic services, as well as advice on data storage, security and retrieval.

Structural interpretation of 42 mutations causing factor XI deficiency using homology modeling.

BACKGROUND: Factor (F)XI is important in the consolidation phase of blood coagulation. The structural effects of mutations causing FXI deficiency have not been well described due to the lack of a structure for FXI. OBJECTIVES: To develop molecular models of the four apple (Ap) and serine protease (SP) domains in FXI in order to assess the structural effects of published FXI mutations in the light of their phenotypes. METHODS: The Ap domains were modeled using the NMR structure of an adhesin from Eimeria tenella. The SP domain was modeled using the crystal structure of beta-tryptase. RESULTS: The effect of 42 mutations causing FXI deficiency was analyzed using homology models for the Ap and SP domains in FXI. Protein misfolding was implicated as the likely structural mechanism of disease in six of 14 mutations in the four Ap domains with Type I phenotypes. Likewise, misfolding was implicated in eight of 14 mutations in the SP domain with Type I phenotypes. Unlike other coagulation factor deficiencies, Type II phenotypes based on a catalytically dysfunctional FXI are uncommon. The structural models indicated that two known Type II mutations in the Ap domains could be correlated with functional defects in substrate or cofactor binding, and likewise four Type II mutations in the SP domain would disrupt the active site. CONCLUSIONS: New FXI disease-causing mutations can now be structurally characterized to complement phenotypic data, and expression studies can be designed to verify the molecular basis of each deficiency.

The rare coagulation disorders--review with guidelines for management from the United Kingdom Haemophilia Centre Doctors' Organisation.

The rare coagulation disorders are heritable abnormalities of haemostasis that may present significant difficulties in diagnosis and management. This review summarizes the current literature for disorders of fibrinogen, and deficiencies of prothrombin, factor V, FV + VIII, FVII, FX, the combined vitamin K-dependent factors, FXI and FXIII. Based on both collective clinical experience and the literature, guidelines for management of bleeding complications are suggested with specific advice for surgery, spontaneous bleeding, management of pregnancy and the neonate. We have chosen to include a section on Ehlers-Danlos Syndrome because haematologists may be consulted about bleeding manifestations in such patients.

Deep vein thrombosis followed by internal jugular vein thrombosis as a complication of in vitro fertilization in a woman heterozygous for the prothrombin 3' UTR and factor V Leiden mutations.

Thrombosis of the internal jugular vein is a rare event but one that can have serious consequences. Most cases reported in the literature have occurred in patients with indwelling central venous catheters, in association with head and neck sepsis, or in hypercoagulable states. However, a small number of cases have been associated with in vitro fertilization and more often with the ovarian hyperstimulation syndrome (OHSS). We report the case of a 30-year-old woman heterozygous for both the prothrombin 3' UTR mutation and for the factor V Leiden mutation who presented with a proximal deep vein thrombosis following in vitro fertilization. She subsequently developed an internal jugular vein thrombosis extending into the subclavian and axillary vein despite therapeutic anticoagulation with a low molecular weight heparin. Thromboembolic events can occur in the absence of other clinical features of OHSS, especially in patients with underlying prothrombotic abnormalities. Neck pain and swelling in a pregnant woman, especially one that has undergone in vitro fertilization, should be taken seriously and investigated with duplex scanning and/or MRI. Women with a personal or family history of thrombosis undergoing in vitro fertilization should be made fully aware of the potential thrombotic risks and should be considered for a thrombophilia screen.

Markers of platelet activation, thrombin generation and fibrinolysis in women with sickle cell disease: effects of differing forms of hormonal contraception.

OBJECTIVE: To examine laboratory markers of platelet activation, thrombin generation and fibrinolysis in women with sickle cell disease (SCD) using the combined oral contraceptive pill (COCP), progestogen only (PO) contraception and non-hormonal contraception. DESIGN: A prospective observational study set in two teaching hospitals in the London region. METHOD: Forty-four women with SCD in steady haematological state using differing hormonal contraception were recruited and venesection was performed at standardised times for the measurements of markers of platelet activation, thrombin generation and fibrinolysis. OUTCOME MEASURES: Prothrombin fragment1+2, plasmin alpha2 antiplasmin complexes, platelet factor 4 (PF-4), beta-thromboglobulin and free protein S antigen (PS-Ag). RESULTS: PS-Ag was decreased and PF-4 increased in all women while the other haemostatic variables were within normal reference ranges. However, there was no statistically significant differences in the measurements of all the haemostatic variables between the three groups of sickle cell women (Kruskal-Wallis, P > 0.05). CONCLUSION: There is anxiety about prescribing the COCP in women with SCD based on the assumption that risk of venous thromboembolism may be compounded by the underlying disease process that occurs with these women. The observed data suggest that SCD women who use the COCP have haemostatic markers which are not statistically different compared with similar women who use PO contraception or non-hormonal contraception. However, a randomized interventional trial would be necessary to evaluate further the safety aspect of COCP use in this group of women.

Internal jugular vein thrombosis following in-vitro fertilization in a woman with protein S deficiency and heterozygosity for the prothrombin 3' UTR mutation, despite anticoagulation with heparin.

We report the case of a 31-year-old woman with protein S deficiency and heterozygosity for the prothrombin 3' UTR mutation who developed an internal jugular vein thrombosis despite therapeutic anticoagulation with a low molecular weight heparin, following in-vitro fertilization. This case indicates that the stimulus to thrombosis in such women is intense and can occur despite apparent therapeutic anticoagulation. Close attention should, therefore, be paid to any women with a personal or family history of thrombosis and the potential thrombotic risks associated with assisted conception must be discussed.

Thrombelastography.

Thrombelastography is a 'near patient' test of coagulation. It is easy to perform and can provide information on a patient's coagulation status within 30 min. Despite more than 25 years of clinical experience, however, several basic questions relating thromboelastograph (TEG) parameters to standard coagulation tests remain unanswered, and the value of the TEG is established only in the setting of orthotopic liver transplantation and cardiopulmonary bypass surgery. This review will focus on the principles and practise of the TEG(R), and data supporting the current accepted uses. Potential future uses will also be discussed including evaluation of hypercoagulable states, and investigating the mechanism of coagulopathies due to drugs or disease that standard tests have failed to unravel.

Survival after induction chemotherapy and surgical resection for high-grade soft tissue sarcoma. Is radiation necessary?

BACKGROUND: Induction chemotherapy can produce dramatic necrosis in sarcomas-raising the question of whether or not radiation is necessary. This study reviews the clinical outcome of a subset of patients with high-grade extremity soft tissue sarcomas (STS) who were treated with induction chemotherapy and surgical resection but without radiation. METHODS: Nonmetastatic, large, high-grade STS of the pelvis and extremities were treated with intra-arterial cisplatin, adriamycin, and, after 1995, ifosfamide. After induction, oncologic resection and histologic evaluation were performed. Good responders with good surgical margins were not treated with radiation. RESULTS: Thirty-three patients, with a median follow-up of 5 years, were included. Limb salvage rate was 94%. Median tumor necrosis was 95%. Four patients developed metastatic disease with three subsequent deaths. Two local recurrences occurred; both patients were salvaged with reresection and adjuvant external beam radiotherapy, although one died of metastatic disease 10 years later. Relapse-free and overall survival is 80% and 88% at 5 and 10 years by Kaplan-Meier analysis. CONCLUSIONS: Intensive induction chemotherapy can be extremely effective for high-grade STS, permitting limb-sparing surgery in lieu of amputation. Radiation may not be necessary if a good response to induction chemotherapy and negative wide margins are achieved. All patients with large, deep, high-grade STS of the extremities should be considered candidates for induction chemotherapy.