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Biomedical subjects

C A Lee

Publications and source records attributed to C A Lee.

At least 91 records · Page 5Linked to original sources
PubMed1999

Factor VIII inhibitors in haemophiliacs: a single-centre experience over 34 years, 1964-97.

A retrospective study of the natural history of factor VIII inhibitors in haemophilia A patients experienced in a single comprehensive haemophilia centre over three decades is reported. 431 haemophilia A patients of all severities have been followed-up for a total of 5626 patient-years. The frequency of inhibitors was 10% in the severe haemophilia A patients and 37% occurred in children <10 years. The majority of the patients received several products before developing the inhibitors. 59% of patients had <50 exposure days and 48% were high responders (>5 BU). An 8-year (1987-95) inhibitor-free period was seen during which all previously untreated patients were treated with an intermediate-purity factor VIII concentrate. A moderate haemophiliac with a missense mutation that has not been described in association with inhibitor is reported. Six HIV-positive patients preserved their antibody response to factor VIII even at the advanced stage of their disease.

Adolescent↗
PubMed1999

Increased bleeding associated with protease inhibitor therapy in HIV-positive patients with bleeding disorders.

The use of protease inhibitor (PI) drugs in treatment regimens for HIV-infected patients with hereditary bleeding disorders has been associated with an increased bleeding tendency. To characterize the nature of this bleeding tendency, a retrospective case record analysis was performed on 67 HIV-positive patients with hereditary bleeding disorders who had been treated with PI therapy. 34 patients (51%) developed an increased bleeding tendency on PI therapy, usually within the first few weeks of treatment. As well as an increase in usual joint bleeds, patients developed spontaneous atypical small joint, soft tissue and muscle bleeds. Haematuria was also common. Bleeding episodes tended to respond suboptimally to factor concentrate replacement. Ritonavir was most likely to be associated with bleeding. Nine patients switched first-line PI therapy as a direct consequence of bleeding and seven had no further bleeding problem on their second PI. Factor concentrate usage was significantly increased during the first 6 months of PI therapy compared to the 6 months preceeding treatment. PI therapy is frequently associated with increased bleeding in patients with hereditary bleeding disorders. The mechanism of the bleeding tendency remains to be elucidated.

Adolescent↗
PubMed1999

Management of liver failure in a haemophilic patient co-infected with human immunodeficiency and hepatitis C viruses.

We present a case of liver failure in a haemophilic patient coinfected with transfusion acquired human immunodeficiency (HIV) and hepatitis C (HCV) viruses. The case illustrates the interaction of multiple viruses with accelerated progression to end stage liver disease and ultimately death. We report the impact on the patient management of two liver biopsies, which diagnosed an initial drug induced hepatitis and subsequently an atypical HCV related hepatitis.

Anti-Bacterial Agents↗
PubMed1999

Assessment of menstrual blood loss and gynaecological problems in patients with inherited bleeding disorders.

Menstrual blood loss and gynaecological problems in patients with inherited bleeding disorders were assessed in this study. One hundred and sixteen women, including 66 with von Willebrand's disease (vWD), 30 carriers of haemophilia and 20 with factor XI (FXI) deficiency were interviewed and their gynaecological history obtained. Their case records were also reviewed and menstrual loss was objectively assessed using a pictorial blood assessment chart (PBAC). Comparison with an age-matched control group (69 women) was performed. Menorrhagia (PBAC score> 100) was confirmed in 74%, 57% and 59% of women with vWD, carriers of haemophilia and FXI deficiency, respectively, in comparison with 29% in the control group (P = 0.001). PBAC scores were higher in vWD patients with a von Willebrand factor activity (vWF:Ac) of </= 30 IU dL-1 compared to those with higher levels, but the difference was not statistically significant. However, there was no relation between PBAC score and the severity of the disease in FXI deficient patients and carriers of haemophilia. Duration of menstruation was significantly longer (P = 0.001) and episodes of flooding was significantly more common (P = 0.001) in patients with inherited bleeding disorders compared to the control group. However, there was no difference in the passage of clots during menstruation. Forty-seven per cent of patients with inherited bleeding disorders had consultations with their family practitioner or gynaecologist for menorrhagia, 36% had medical treatment and 27% had surgical procedures, including 10 hysterectomies. Post-operative bleeding followed in four out of 28 cases of hysteroscopy and/or dilatation and curettage. Bleeding complications following hysterectomy were reported in five out of 10 patients. In conclusion, menorrhagia is a common and major problem in patients with inherited bleeding disorders, especially vWD. Increased awareness among gynaecologists and haematologists of the high prevalence of menorrhagia and the treatment options available is necessary for optimal management of these patients. Appropriate preoperative assessment and haemostatic control during any gynaecological procedure, however minor, and in collaboration with the local haemophilia centre is essential to minimize risks of haemorrhagic complications.

Adolescent↗
PubMed1999

Acquired von Willebrand syndrome--report of 10 cases and review of the literature.

Acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder with clinical and laboratory features closely resembling hereditary von Willebrand disease (vWD), arising in previously haemostatically normal individuals. We present a retrospective review of 10 cases with AvWS diagnosed over 17 years. The severity of the bleeding tendency varied from mild to severe forms. Multimers electrophoresis showed that 8/10 patients had a normal pattern similar to type 1 vWD, 1/10 had a type 2A vWD pattern (with absence of high and intermediate molecular weight multimers) and 1/10 had a type 3 vWD pattern. An inhibitor screen was performed in 6/10 patients and autoantibodies against von Willebrand factor were found in only two cases. The underlying cause/associated conditions were identified in 8/10 patients. Treatment of the bleeding diathesis was successfully achieved with desmopressin or clotting factor concentrates. Resolution of underlying hypothyroidism (in two cases) and multiple myeloma (in one case) led to normalization of the coagulation parameters. The report on this cohort of 10 patients with AvWS illustrates the complexity of AvWS and its multifactorial aetiology. A brief review of the recent literature on AvWS is also presented, with emphasis on the current opinions in pathogenesis and treatment. Acquired von Willebrand syndrome (AvWS) is an acquired bleeding disorder, characterized by a phenotype similar to the inherited von Willebrand disease (vWD), with a prolonged bleeding time and low plasma levels of factor VIII - von Willebrand factor (vWF) measurements. It occurs in patients with no family history of vWD, who present with recent onset of bleeding symptoms. AvWS appears to be associated mainly with lymphoproliferative disorders, immunological conditions and neoplasia. AvWS is a rare condition and it is difficult to conduct prospective studies, therefore it is important to document the experience with such cases. The aim of this paper is first, to report 10 cases of AvWS identified at our Haemophilia Centre during the past 17 years. Second, to present a brief review of the recent literature on AvWS - outlining the salient features, associated disorders, mechanisms of acquisition and the available options of treatment.

Adult↗
PubMed1999

Audit of clinical management of von Willebrand disease during 1997 at a single institution and review of treatment patterns between 1980 and 1997.

In 1997 the UK Haemophilia Centre Directors Organization published the guidelines for diagnosis and management of von Willebrand disease (vWD). The guidelines stated that desmopressin (DDAVP) should be used in type 1 and type 2N vWD, that it might be useful in other types 2 vWD and that it is ineffective in type 3 vWD. If patients are unresponsive to DDAVP or if it is contraindicated, the treatment of choice is clotting factor concentrates (CFC). In the light of these guidelines, we audited our practice for 1997. Furthermore, we undertook a retrospective review of the changing patterns of treatment of vWD between 1980 and 1997. During 1997, 10 patients with vWD received DDAVP and another 30 patients were treated with CFC (a total of 1.2 million IU): Haemate P (Centeon, Germany) and/or 8Y (BPL, Elstree, UK). Few patients had clear contraindications to DDAVP, but several patients with type 1 and 2 vWD received CFC on the basis of age or reduced levels of von Willebrand factor - where DDAVP was considered suboptimal for adequate haemostasis. However, this assumption was made without a preliminary test dose to assess the response to DDAVP. The analysis of treatment of vWD for the past 17 years showed that cryoprecipitate was discontinued from use in the early 1990s and that both DDAVP and CFC usage has been on the increase. In conclusion, the audit illustrated a general good adherence to guidelines but it highlighted the need for a DDAVP test before using CFC.

Blood Coagulation Factors↗
PubMed1999

Assessing health-related quality-of-life in individuals with haemophilia.

The objectives of this study were to analyse current levels of health-related quality-of-life (HR-QoL) in individuals with severe haemophilia and to assess the scope for these levels to improve. To do this, 249 individuals with severe, moderate and mild haemophilia were asked to complete Medical Outcomes Study (MOS) Short-Form 36 (SF-36) and EuroQol (EQ-5D) questionnaires. Access was also gained to two appropriate normative data sets. The results from these questionnaires showed that HIV status, history of orthopaedic surgery and bleeding frequency in the previous calendar year were not strong predictors of HR-QoL for individuals with severe haemophilia. However, for the majority of scales, age was found to be a strong predictor of HR-QoL for this patient group. The results from the analysis also showed that compared to individuals with moderate/mild haemophilia and the UK male normative population, individuals with severe haemophilia generally recorded poorer levels of HR-QoL. These results suggest, therefore, that individuals with severe haemophilia have reduced levels of HR-QoL compared to individuals with moderate/mild haemophilia and the general population, irrespective of differences in age. The results also suggest that the scope for primary prophylaxis to increase HR-QoL in individuals with severe haemophilia is significant.

Adult↗
PubMed1999

Two AraC/XylS family members can independently counteract the effect of repressing sequences upstream of the hilA promoter.

During infection of its hosts, Salmonella enterica serovar Typhimurium (S. typhimurium) enters the epithelial cells of the small intestine. This process requires a number of invasion genes encoded on Salmonella pathogenicity island 1 (SPI1), a 40 kb stretch of DNA located near minute 63 of the S. typhimurium chromosome. Expression of S. typhimurium SPI1 invasion genes is activated by the transcription factor HilA. hilA is tightly regulated in response to many environmental conditions, including oxygen, osmolarity and pH. Regulation of hilA expression may serve to limit invasion gene expression to the appropriate times during Salmonella infection. We have mapped the transcription start site of hilA and identified regions of the promoter that are required for the repression of hilA expression by conditions unfavourable for Salmonella invasion. We have also identified two SPI1-encoded genes, hilC and hilD, that can independently derepress hilA expression. HilC and HilD are both members of the AraC/XylS family of transcriptional regulators. A mutation in hilD significantly reduces the ability of S. typhimurium to enter tissue culture cells, whereas a mutation in hilC only modestly affects Salmonella invasion. Based on these results, we have updated our model of Salmonella SPI1 invasion gene regulation. We also speculate on the possible significance of this model for Salmonella pathogenesis.

AraC Transcription Factor↗
PubMed1999

Allergic lung responses are increased in prostaglandin H synthase-deficient mice.

To investigate the function of prostaglandin H synthase-1 and synthase-2 (PGHS-1 and PGHS-2) in the normal lung and in allergic lung responses, we examined allergen-induced pulmonary inflammation and airway hyperresponsiveness in wild-type mice and in PGHS-1(-/-) and PGHS-2(-/-) mice. Among nonimmunized saline-exposed groups, we found no significant differences in lung function or histopathology, although PGE(2) was dramatically reduced in bronchoalveolar lavage (BAL) fluid from PGHS-1(-/-) mice, relative to wild-type or PGHS-2(-/-) mice. After ovalbumin sensitization and challenge, lung inflammatory indices (BAL cells, proteins, IgE, lung histopathology) were significantly greater in PGHS-1(-/-) mice compared with PGHS-2(-/-) mice, and both were far greater than in wild-type mice, as illustrated by the ratio of eosinophils in BAL fluid (8:5:1, respectively). Both allergic PGHS-1(-/-) and PGHS-2(-/-) mice exhibited decreased baseline respiratory system compliance, whereas only allergic PGHS-1(-/-) mice showed increased baseline resistance and responsiveness to methacholine. Ovalbumin exposure caused a modest increase in lung PGHS-2 protein and a corresponding increase in BAL fluid PGE(2) in wild-type mice. We conclude that (a) PGHS-1 is the predominant enzyme that biosynthesizes PGE(2) in the normal mouse lung; (b) PGHS-1 and PGHS-2 products limit allergic lung inflammation and IgE secretion and promote normal lung function; and (c) airway inflammation can be dissociated from the development of airway hyperresponsiveness in PGHS-2(-/-) mice.

Allergens↗
PubMed1999

Anovulation in cyclooxygenase-2-deficient mice is restored by prostaglandin E2 and interleukin-1beta.

Mice carrying a null mutation for either of the two cyclooxygenase (COX) isoenzymes, necessary for prostanoid production, exhibit several isotype-specific reproductive abnormalities. Mice deficient in COX-1 are fertile but have decreased pup viability, whereas mice deficient in COX-2 fail to ovulate and have abnormal implantation and decidualization responses. The present study identifies the specific contribution of each COX isoenzyme in hypothalamic, pituitary, and ovarian function and establishes the pathology and rescue of the anovulatory syndrome in the COX-2-deficient mouse. In both COX-1- and COX-2-deficient mice, pituitary gonadotropins were selectively increased, whereas hypothalamic LHRH and serum gonadotropin levels were similar to those in wild-type animals (+/+). No significant differences in serum estrogen or progesterone were noted among the three genotypes. Exogenous gonadotropin stimulation with PMSG and hCG produced a comparable 4-fold increase in ovarian PGE2 levels in wild-type and COX-1(-/-) mice. COX-2(-/-) mice had no increase in PGE2 over PMSG-stimulated levels. Wild-type and COX-1(-/-) mice ovulated in response to PMSG/hCG; very few COX-2(-/-) animals responded to this regimen. The defect in ovulation in COX-2 mutants was attributed to both an abnormal cumulus oophorum expansion and subsequent stigmata formation. Gonadotropin stimulation and concurrent treatment with PGE2 or interleukin-1beta resulted in ovulation of COX-2(-/-) mice comparable to that in COX-2(+/+), whereas treatment with PGF2alpha was less effective. Collectively, these data demonstrate that COX-2, but not COX-1, is required for the gonadotropin induction of ovarian PG levels; that COX-2-related prostanoids are required for stabilization of the cumulus oophorum during ovulation; and that ovulation can be restored in the COX-2(-/-) animals by simultaneous treatment with gonadotropins and PGE2 or interleukin-1beta.

Animals↗
PubMed1999

Management of aortobronchial fistula with an aortic stent-graft.

Aortobronchial fistula presenting as massive hemoptysis is a rapidly fatal process that is extremely difficult to manage. We report a case in which endovascular occlusion of a fistula between a thoracic aortic pseudoaneurysm and lung was successfully managed by placement of an aortic endovascular stent-graft. Stent-grafting is a promising technique in managing complications of thoracic aneurysms and grafts.

Aged↗
PubMed1999

Women and inherited bleeding disorders: menstrual issues.

Von Willebrand, who described a bleeder family from Aland in 1926 in whom the index patient died at the fourth menses, stated, "the trait seems to be seen among women." Menorrhagia is defined objectively as a menstrual blood loss of at least 80 mL. However, even though 5% of women aged 30 to 49 years consult their general practitioner and 12% of gynecologic referrals are for menorrhagia, the diagnosis is difficult. A pictorial bleeding assessment chart (PBAC) has a specificity and sensitivity of more than 80%, with a score of > or = 100 being equivalent to more than 80 mL of blood loss. Using this chart to screen 150 women with menorrhagia who attended a gynecology clinic, an inherited bleeding disorder was diagnosed in 17%. Menorrhagia with onset at the menarche was predictive of an inherited bleeding disorder in 65% of von Willebrand's disease (vWD) and 67% of factor XI (FXI)-deficient patients. A retrospective survey in patients with inherited bleeding disorders using the PBAC showed menorrhagia in 74% of patients with vWD, 57% of carriers of hemophilia A or B, and 59% of FXI-deficient patients, compared with 29% of control individuals. Menorrhagia was the most common symptom in 60% of patients with FVII deficiency studied. Menorrhagia in women with bleeding disorders can be controlled with tranexamic acid with good effect. More recently, a desmopressin acetate (DDAVP) spray has been shown to achieve good FVIII and von Willebrand factor (vWF) levels and is efficacious for women with these deficiencies. The oral contraceptive pill may be useful. Since bleeding disorders are found in a substantial number of women with menorrhagia, it is important that such patients are investigated for these disorders before invasive procedures are done; hysteroscopy and hysterectomy in these patients are associated with a high rate of postoperative bleeding.

Family Health↗
PubMed1999

Variations in coagulation factors in women: effects of age, ethnicity, menstrual cycle and combined oral contraceptive.

To assess variations of coagulation factors in women, 123 women were included in a cross-sectional study of the effect of age, ethnic origin, blood group and menstrual cycle on surface induced coagulation time (activated partial thromboplastin time) and plasma levels of Factor VIII clotting assay, von Willebrand factor antigen, von Willebrand factor activity and factor XI. The effect of menstrual cycle was further assessed in a longitudinal study including 39 Caucasian women, 20 of whom were using combined oral contraceptives. Activated partial thromboplastin time was longer in women with blood groups B or O, and plasma levels of factor VIII clotting assay, von Willebrand factor antigen and von Willebrand factor activity were significantly higher in black women. Fibrinogen, von Willebrand factor antigen and von Willebrand factor activity concentrations showed strong cyclic variations with peak values in the luteal phase. This pattern was dampened for von Willebrand factor antigen and von Willebrand factor activity but completely disappeared for fibrinogen with the use of combined oral contraceptives. There was a cyclical pattern for factor VIII clotting assay in pill users, evidence of which was not evident in non-pill users. There were strong associations between the levels of von Willebrand factor antigen and von Willebrand factor activity and age, with levels rising by an average of 0.17 and 0.15 U/ml, respectively, for each 10 year increase in age. In conclusion, there are great inter- and intraindividual variations in coagulation markers in women due to different physiological conditions such as age, ethnicity, blood group and phases of the menstrual cycle. However, there were no significant associations between coagulation markers and weight, alcohol consumption or smoking status.

Adolescent↗
PubMed1999

Pharmacokinetics of recombinant factor VIII (recombinate) using one-stage clotting and chromogenic factor VIII assay.

In a study designed to demonstrate the safety and pharmacokinetics of a recombinant factor VIII (Recombinate) manufactured in Andover, MA and Thousand Oaks, CA, two different methods of factor VIII assay (one-stage clotting and Chromogenic substrate) were compared in vivo. The study was performed in four centres in the UK: London, Oxford, Cardiff and Manchester. Two pharmacokinetic studies, at least one week apart, were performed in 30 patients with severe haemophilia A (VIII:C < 2 IU/dl). A dose of 50 IU/kg was administered with sampling pre-infusion, and +0.25, 0.5, 1, 3, 6, 9, 12 and 24 h post-infusion. The aggregate 60 pharmacokinetic study showed a half-life of 12.7 and 13.0 h (p = 0.28) and recovery of 127 and 161 IU/dl (p = 0.0001) using one-stage clotting or chromogenic substrate respectively. In a supplementary experiment, 20 post-infusion samples were re-assayed by 1-stage and chromogenic assay using two plasma (20th British plasma standard and an "in-house" pooled normal plasma) and two concentrate standards, derived from the same type, but different batch of infused concentrate (Recombinate) and pre-diluted in either individual pre-infusion sample or in pooled commercial haemophilic plasma. The use of the Recombinate concentrate standard overcame the significant difference in FVIII levels between 1-stage and chromogenic assay methods when a plasma standard was used (p <0.0001). It is concluded that where potency dosing designation is carried out by an assay system different to that used in the clinical situation, the use of the recombinant concentrate as a standard in post-infusion plasma samples is likely to give more reliable and reproducible results.

Biological Assay↗
PubMed1998

Immune markers and viral load after HIV-1 seroconversion as predictors of disease progression in a cohort of haemophilic men.

OBJECTIVE: To assess the prognostic value of HIV RNA levels measured shortly after HIV seroconversion and whether markers of immune response (CD4+ and CD8+ T-cell counts, IgA and IgG) measured at the same time, continue to provide prognostic information once the HIV RNA level is known. DESIGN AND METHODS: HIV RNA levels were measured approximately 2.5 years after seroconversion in 97 haemophilic men followed for up to 17 years. Levels of CD4+ and CD8+ T cells, IgA and IgG were measured within 1 year of the HIV RNA level. The relationships between these markers and progression to AIDS and death were studied using Kaplan-Meier plots and proportional hazards regression models. RESULTS: High HIV RNA levels were associated with faster progression to AIDS and shorter survival in univariate Cox regression models. High IgA and IgG levels were also associated with faster disease progression. In multivariate models, high HIV RNA levels remained independently associated with faster disease progression [relative hazard (RH), 1.86; P = 0.01 for AIDS; RH, 1.66; P = 0.05 for death). However, high IgA and IgG levels provided strong independent prognostic information for AIDS and death (IgA: RH, 1.38; P = 0.006 for AIDS; RH, 1.33; P = 0.07 for death; IgG: RH, 1.10; P = 0.02 for AIDS; RH, 1.12; P = 0.01 for death). CONCLUSIONS: Our results confirm the importance of the HIV RNA level in assessing the long-term prognosis in individuals infected with HIV. However, our results suggest that immune activation markers, rather than merely reflecting high HIV RNA levels are important in assessing prognosis in their own right. These findings may improve our understanding of HIV pathogenesis and may aid clinical management of patients.

Biomarkers↗