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Biomedical subjects

C A Lee

Publications and source records attributed to C A Lee.

At least 19 recordsLinked to original sources
PubMed2006

Update on the pathophysiology and classification of von Willebrand disease: a report of the Subcommittee on von Willebrand Factor.

von Willebrand disease (VWD) is a bleeding disorder caused by inherited defects in the concentration, structure, or function of von Willebrand factor (VWF). VWD is classified into three primary categories. Type 1 includes partial quantitative deficiency, type 2 includes qualitative defects, and type 3 includes virtually complete deficiency of VWF. VWD type 2 is divided into four secondary categories. Type 2A includes variants with decreased platelet adhesion caused by selective deficiency of high-molecular-weight VWF multimers. Type 2B includes variants with increased affinity for platelet glycoprotein Ib. Type 2M includes variants with markedly defective platelet adhesion despite a relatively normal size distribution of VWF multimers. Type 2N includes variants with markedly decreased affinity for factor VIII. These six categories of VWD correlate with important clinical features and therapeutic requirements. Some VWF gene mutations, alone or in combination, have complex effects and give rise to mixed VWD phenotypes. Certain VWD types, especially type 1 and type 2A, encompass several pathophysiologic mechanisms that sometimes can be distinguished by appropriate laboratory studies. The clinical significance of this heterogeneity is under investigation, which may support further subdivision of VWD type 1 or type 2A in the future.

ADAM Proteins↗
PubMed2006

Rhinological, laryngological, oropharyngeal and other head and neck side effects of drugs.

Following a previous paper in which we documented the otological side effects of drug therapy, we here review other drug side effects that ENT surgeons may encounter when dealing with patients. Although otological drug side effects such as hearing loss and tinnitus are well recognized there are many rhinological, laryngeal, oropharyngeal and other head and neck drug side effects. Our data were sourced from the British National Formulary and Electronic Medical Compendium websites.

Databases, Factual↗
PubMed2006

Disorders of menstruation and their effect on the quality of life in women with congenital factor VII deficiency.

AIMS AND OBJECTIVES: To review menstrual problems in women with congenital FVII deficiency and to study their effect on the quality of life during menstruation in women with congenital FVII deficiency. METHOD: 14 women with congenital factor VII deficiency registered with the Haemophilia Centre at the Royal Free Hospital were interviewed and their case notes reviewed. All women completed Pictorial Blood assessment Chart (PBAC) for assessment of menstrual blood loss and a quality of life questionnaire during menstruation. Similar questionnaire and PBAC was completed by an age matched healthy control group of 23 women. RESULTS: Median age of study group was 35 yrs and of control group 34 yrs. Median FVII level of the study group was 31.5 IU/dL Two women had severe FVII deficiency (FVII level < 10 IU/dL) and 12 women had mild-moderate FVII deficiency. 57% women (8/14) from study group had menorrhagia (PBAC score > 100) compared with 17% (4/23) women from the control group. Six women (43%) from the study group were diagnosed with anaemia due to heavy periods, compared to two (9%) in the control group. The quality of life scores during menstruation were significantly worse in the women with FVII deficiency, compared to controls. CONCLUSION: Women with factor VII deficiency exhibit a spectrum of bleeding symptoms, menorrhagia being one of the commonest symptoms. This has adverse effect on their quality of life.

Activities of Daily Living↗
PubMed2006

Identification and management of women with inherited bleeding disorders: a survey of obstetricians and gynaecologists in the United Kingdom.

A mail survey of members and fellows of Royal College of Obstetricians and Gynaecologists was carried out to determine current practices of obstetricians and gynaecologists in the United Kingdom in the management of women with inherited bleeding disorders. In total, 3929 questionnaires were sent, 707 returned and analysis was limited to 545 valid questionnaires. In the past 5 years, 91% have managed women with inherited bleeding disorders. The majority (83%) considered inherited bleeding disorders to be under diagnosed in obstetrics and gynaecology. More than 80% considered the prevalence of von Willebrand's disease (VWD) to be <0.2% in the general population and <1% in women with menorrhagia and no gynaecological pathology, although the reported prevalence is 1% and 5-25% respectively. Twelve percent of the respondents would arrange testing for VWD when reviewing an 18-year-old with menorrhagia and no pelvic pathology, while only 2% would do the same for a 35-year-old with the same presentation. Twenty-one percent thought elective caesarean section is indicated in all fetuses known to be at risk of being affected by haemophilia. Eighty-four percent considered vacuum extraction unsafe in these cases, but 76% would consider the use of low forceps. In conclusion, obstetricians and gynaecologists underestimate inherited bleeding disorders as an underlying cause for menorrhagia. Increased awareness and management guidelines are essential in minimizing haemorrhagic complications and improving quality of care of these women.

Adolescent↗
PubMed2006

Pregnancy in women with congenital factor VII deficiency.

The aim was to review the pregnancy and obstetric outcome in women with factor VII (FVII) deficiency. The study group contained women with FVII deficiency, registered with Haemophilia centre and Haemostasis Unit at the Royal Free Hospital, London. The women were interviewed and case notes were reviewed. The main outcome measures were changes in FVII levels in pregnancy, maternal and perinatal outcome. The FVII levels ranged from 7-36 IU dL(-1) in the 13 women included in the study. There were a total of 14 pregnancies in seven women. Ten pregnancies in four women were prior to the diagnosis of FVII deficiency. Following the diagnosis of FVII deficiency, there were four pregnancies in three women. There was an increase in the FVII level during pregnancy in these women from a mean baseline level of 33 IU dL(-1) to a mean of 73 IU dL(-1). These women received recombinant FVIIa replacement during labour and delivery. There were two early pregnancy losses, both associated with excessive haemorrhage. There was only one postpartum haemorrhage in the study. There is a significant increase in FVII levels in pregnancy in women with heterozygous FVII deficiency. The risk of bleeding in early pregnancy might be higher than that at term, due to inadequate rise in the FVII level in early pregnancy.

Abortion, Spontaneous↗
PubMed2006

The obstetric and gynaecological management of women with inherited bleeding disorders--review with guidelines produced by a taskforce of UK Haemophilia Centre Doctors' Organization.

The gynaecological and obstetric management of women with inherited coagulation disorders requires close collaboration between obstetrician/gynaecologists and haematologists. Ideally these women should be managed in a joint disciplinary clinic where expertise and facilities are available to provide comprehensive assessment of the bleeding disorder and a combined plan of management. The haematologist should arrange and interpret laboratory tests and make provision for appropriate replacement therapy. These guidelines have been provided for healthcare professionals for information and guidance and it is also intended that they are readily available for women with bleeding disorders.

Blood Coagulation Disorders, Inherited↗
PubMed2006

Screening for factor XI deficiency amongst pregnant women of Ashkenazi Jewish origin.

A pilot study was conducted over a 6-month period to evaluate antenatal screening for factor XI (FXI) deficiency amongst Ashkenazi Jewish women booking for their pregnancy in a single obstetric unit. Fifty-four women of Ashkenazi Jewish origin were recruited during their visit for the routine first trimester ultrasound scan. They completed a questionnaire about their personal bleeding symptoms and had blood taken for FXI levels (FXI:C). Seven (13%) women had partial FXI deficiency. Five (9%) were newly diagnosed, and in the remaining two, the diagnosis was known previously. One infant with severe FXI deficiency was identified as a result of maternal testing. This study has shown that FXI deficiency is common amongst women of Ashkenazi Jewish origin and supports its antenatal screening in this population. However, further studies are required to evaluate its cost-effectiveness and the effect on pregnancy outcome.

Adult↗
PubMed2006

Heterotropic bone formation as a complication of elective joint replacement in haemophilic patients - a case report and literature review.

We report two cases of this rare postoperative condition. Both patients having undergone extensive surgery to their hips, developed increased bone growth in the soft tissue of the hip, accounting for the reduced range of movement, pain and stiffness. Plain x-rays taken confirmed the presence of heterotopic ossification, also known as a variant of myositis ossificans. We review the literature and discuss treatment options of this rare condition in patients with end-stage haemophilic arthropathy.

Aged↗
PubMed2006

The 80th anniversary of von Willebrand's disease: history, management and research.

The history of von Willebrand's disease (VWD) is fascinating because it demonstrates how good clinical observations, genetic studies and biochemical skills can improve basic understanding of a disease and its management. The continuous efforts of scientists and clinicians during the last 80 years have significantly improved the knowledge of von Willebrand factor (VWF) structure and function and the management of VWD. Diagnosis of phenotype and genotype is now available in many countries and treatment is becoming more specific according to the VWD type. Any therapeutic agents must correct the dual defect of haemostasis, i.e. the abnormal platelet adhesion due to reduced and/or dysfunctional and low levels of factor VIII (FVIII) associated with VWF defects. Desmopressin (DDAVP) is the treatment of choice for type 1 VWD because it induces release of VWF from cellular compartments. Plasma virally inactivated VWF concentrates containing FVIII are effective and safe in patients unresponsive to DDAVP. There are advanced plans to develop a recombinant VWF but this product will require the concomitant administration of FVIII for the control of acute bleeds. Basic research studies on cellular biology, biochemistry and immunology have confirmed the role of VWF as a crucial participant in both haemostasis and thrombosis as its main biological activity is to support platelet adhesion-aggregation in the circulation. Retrospective and prospective clinical research studies, including bleeding history and laboratory markers for diagnosis as well as the use of DDAVP and VWF concentrates to manage or prevent bleeds in patients with VWD have been essential to provide general guidelines for VWD management. The large number of publications quoting VWD and VWF emphasizes the important role of VWF in medicine.

Clinical Trials as Topic↗
PubMed2006

Non-invasive first trimester determination of fetal gender: a new approach for prenatal diagnosis of haemophilia.

Ten carriers of haemophilia referred for prenatal diagnosis were offered first trimester non-invasive fetal gender determination by ultrasound and analysis of free fetal DNA (ffDNA) in maternal plasma in an attempt to reduce the need for an invasive diagnostic procedure in female pregnancies. Although repeat testing was required in three cases, fetal gender was determined correctly in all cases (four females, six males) at a median gestation of 12(+3) (11(+2) to 14(+1)) using both methods. In all cases of a female fetus, the mothers opted not to have invasive testing. Both methods provide a reliable option of avoiding invasive testing in female pregnancies.

DNA↗
PubMed2005

Stenting for bilateral congenital choanal atresia--a new technique.

We describe a new nasal stent for the treatment of bilateral congenital choanal atresia. The stent is made up of reinforced endotracheal tube mounted on a portex carrier tube. It potentially causes less internal crusting and stent blockage and is secured without sutures. It remains patent for at least 4 weeks. We have used the stent successfully in six patients between 1998 and 2004 at Leeds General Infirmary and present the data collected retrospectively. The current practice in the UK for treatment and stenting for congenital choanal atresia was investigated by a prospective internet based questionnaire sent to 18 consultant paediatric otolaryngologists of whom 12 (67%) responded. Their experience and results are reported. The literature has been reviewed.

Choanal Atresia↗
PubMed2005

Ortner syndrome and haemophilia.

Compression and paralysis of the left recurrent laryngeal nerve by a dilated pulmonary artery is a rare complication of pulmonary hypertension. We here report the case of a patient with severe haemophilia A and HIV infection who presented with a persistent hoarseness of voice and a left vocal cord palsy caused by HIV-associated pulmonary hypertension. This case suggests that HIV-associated pulmonary hypertension should be suspected in any HIV patient presenting with unexplained left vocal cord palsy.

Adult↗
PubMed2005

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.

Amino Acid Sequence↗
PubMed2005

Pharmacokinetic studies on Wilfactin, a von Willebrand factor concentrate with a low factor VIII content treated with three virus-inactivation/removal methods.

OBJECTIVE: In order to correct the primary von Willebrand factor (VWF) defect and avoid supra-physiologic plasma levels of factor VIII, a pure VWF concentrate almost devoid of FVIII was developed and used in France since 1989. METHODS: The pharmacokinetic (PK) profile of the most recent version of this concentrate (Wilfactin; LFB, Les Ulis, France), treated with three virus-inactivation/removal methods (solvent/detergent, 35 nm filtration, dry heat treatment), was investigated in 25 patients. Seventeen patients with various types of clinically severe von Willebrand disease (VWD) were included in a crossover, randomized trial carried out in five European centers and comparing Wilfactin with concentrates containing both FVIII and VWF (FVIII/VWF). Eight type 3 VWD patients were included in another trial carried out in six French centers comparing Wilfactin with its previous version (Facteur Willebrand-LFB; LFB) that adopted one virus-inactivation method only. RESULTS: For both the measurements evaluated in this study (VWF antigen, VWF:Ag; and VWF ristocetin co-factor activity, VWF:RCo), Wilfactin had a PK profile similar to that of the FVIII/VWF concentrates and of Facteur Willebrand-LFB. VWF:RCo and VWF:Ag recoveries were 2.1 +/- 0.3 and 1.8 +/- 0.3 per IU kg(-1), respectively, and the half-lives were 12.4 +/- 1.8 and 15.9 +/- 1.5 h. The FVIII synthesis rate was 5.8 +/- 1.0 IU dL(-1) h(-1), with a half-life of 15.8 +/- 2.4 h. CONCLUSION: The PK of VWF and FVIII have not been altered by the three virus-inactivation/removal steps during the manufacturing of Wilfactin.

Adult↗
PubMed2005

Spontaneous rupture of the cervical oesophagus following nose blowing: a case report.

Spontaneous rupture of the oesophagus is a rare event. Most have been reported in association with oesophageal carcinoma, peptic ulceration and alcohol abuse followed by forceful episode of vomiting. We, however, report a case of spontaneous rupture of the oesophagus in an otherwise healthy individual with no history of alcohol intake, as a consequence of blowing of the nose.

Adult↗
PubMed2005

Otologic side effects of drugs.

Otolaryngologic symptoms are common and patients presenting to the otolaryngologist will often be taking drugs for the treatment of unrelated diseases. As a doctor, one must not forget the potential of these drugs to cause otologic side effects and, in some cases, to be the cause of the presenting symptom. We performed a comprehensive search of the British National Formulary and Electronic Medical Compendium websites to classify the otologic side effects caused by drugs. Not all the data were found at both websites. We have compiled all the data together, subclassified them and produced a review of the otologic side effects of drugs, in table form.

Dizziness↗
PubMed2004

Setting research priorities to improve cost-effectiveness estimations of primary prophylaxis with clotting factor for people with severe haemophilia.

Primary prophylaxis with clotting factor is the clinical treatment of choice for people with severe haemophilia, as evidence suggests it can prevent the onset and progression of joint- and muscle-related problems caused by bleeding episodes. However, the major limitation of this approach is that it requires considerably more clotting factor compared with treating on-demand. Thus, there is a need to establish its cost-effectiveness. The aim of this paper is to review the published evidence on the cost-effectiveness of prophylaxis and to highlight areas for future research that would decrease the uncertainty around these findings.

Absenteeism↗