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C A Lee

Publications and source records attributed to C A Lee.

At least 109 records · Page 6Linked to original sources
PubMed1998

Structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3C protease inhibitors. 1. Michael acceptor structure-activity studies.

The structure-based design, chemical synthesis, and biological evaluation of peptide-derived human rhinovirus (HRV) 3C protease (3CP) inhibitors are described. These compounds incorporate various Michael acceptor moieties and are shown to irreversibly bind to HRV serotype 14 3CP with inhibition activities (kobs/[I]) ranging from 100 to 600 000 M-1 s-1. These inhibitors are also shown to exhibit antiviral activity when tested against HRV-14-infected H1-HeLa cells with EC50's approaching 0.50 microM. Extensive structure-activity relationships developed by Michael acceptor alteration are reported along with the evaluation of several compounds against HRV serotypes other than 14. A 2.0 A crystal structure of a peptide-derived inhibitor complexed with HRV-2 3CP is also detailed.

3C Viral Proteases↗
PubMed1998

Frequency of inherited bleeding disorders in women with menorrhagia.

BACKGROUND: Although menorrhagia is a common gynaecological symptom, a specific cause is identified in less than 50% of affected women. We investigated the frequency of inherited bleeding disorders in women with menorrhagia. METHODS: Women referred for investigation of menorrhagia whose pelvis was normal on clinical examination and who had an estimated menstrual blood loss of more than 80 mL were studied. A detailed menstrual history and history about other bleeding symptoms was taken. The activated partial thromboplastin time, factor VIII activity, von-Willebrand-factor antigen and activity, and factor XI (FXI) were measured in all patients; further tests were done when results were at or outside the limits of the assays. FINDINGS: 150 women were screened. An inherited bleeding disorder was diagnosed in 26 (17%) patients: the disorders were von Willebrand's disease of mild (15) or moderate severity (three), mild FXI deficiency (four), mild von Willebrand's disease and FXI deficiency (one), combined von Willebrand's disease, FXI deficiency, and factor X deficiency (one), carriage of haemophilia-A gene (one), and platelet dysfunction (one). The frequency of von Willebrand's disease and FXI deficiency were 13% (95% CI 7.9-18.8%) and 4% (1.5-8.5%), respectively. Menorrhagia since menarche was noted in 11 (8.9%) of 123 women without a bleeding disorder compared with 13 (65%) of 20 women with von Willebrand's disease (p=0.001) and four (66.7%) of six women with FXI deficiency (p<0.001). INTERPRETATION: Inherited bleeding disorders are found in a substantial proportion of women with menorrhagia and a normal pelvis examination. We suggest that such patients should be investigated for these disorders-especially von Willebrand's disease-before invasive procedures are done.

Adult↗
PubMed1998

Influence of HIV-1 infection on GBV-C infection in multiply infected haemophilic patients.

Two hundred thirteen haemophilic patients were studied for the presence of GBV-C RNA and anti-E2 antibodies soon after their first treatment with unsterilised factor concentrates and in their most recent sample. An assessment was made to determine whether coinfection with HIV had any effect on the progression of GBV-C infection. All of the patients were infected with HCV and 81 patients (37%) were also infected with HIV. GBV-C RNA was detected using the Abbott LCx(TM) assay and by RT-PCR. Anti-E2 antibodies were detected using the microPLATE Anti-HGenv assay and by Abbott Laboratories. The HIV-negative patients were more likely than the HIV-positive patients to lose GBV-C RNA between the two time points. A proportion of the patients lost their anti-E2 antibodies over the time period, however, the majority of these were HIV-positive. This study shows that infection with HIV does affect the progression of GBV-C infection, however, this effect is little understood as yet.

Disease Progression↗
PubMed1998

2,3,7,8-Tetrachlorodibenzo-p-dioxin induction of cytochrome P450-dependent arachidonic acid metabolism in mouse liver microsomes: evidence for species-specific differences in responses.

Arachidonic acid is biotransformed to metabolites active in signal transduction by cytochrome P450 (CYP) as well as by cyclooxygenase and lipoxygenase enzymes. Inducers of CYP1 enzymes, including 2,3,7,8-tetrachlorodibenzo-p-dioxin and other Ah receptor ligands, markedly increase liver microsomal CYP-dependent arachidonic acid epoxygenation in chicks but depress epoxygenation in rat liver microsomes where they elicit about twofold increases in formation of other CYP products, omega-1 to omega-4-OH arachidonic acid. These studies examined the effect of TCDD on metabolism of [1-14C]-labeled arachidonic acid by mouse liver microsomes. Mouse liver microsomes metabolized arachidonic acid exclusively by a CYP-dependent mechanism as evidenced by lack of metabolism in the absence of NADPH and by formation of specific CYP-dependent metabolites. The major constitutive products were epoxygenase products (EETs and EET-diols) and omega-OH arachidonic acid. Treatment with TCDD increased formation of omega-2- to omega-4-OH arachidonic acid products 23-fold, formation of omega-1-OH arachidonic acid about 5-fold, and formation of epoxygenase products and HETEs each about twofold. In contrast, TCDD treatment decreased formation of omega-OH arachidonic acid by over 70%. EET-diols comprised a greater fraction of total epoxygenase products in mouse liver microsomes than has been found for liver microsomes of other species. The high EET-diol formation was attributable to a non-TCDD-inducible, EET epoxide hydrolase activity in mouse liver microsomes. For comparison, the effect of TCDD on [1-14C]-labeled arachidonic acid was examined in homogenates of spleen, an immune system target of TCDD. While levels of total [1-14C]-arachidonic acid metabolism were comparable in both tissues, virtually all of the metabolism by spleen was CYP-independent, and it was unaffected by TCDD. Western blotting experiments showed that TCDD-induced mouse Cyp1a1 and 1a2 share immunologic epitopes with chick CYP1A4 and 1A5. However, in immunoinhibition studies, an antibody to CYP1A5, the chick arachidonate epoxygenase, was ineffective against TCDD-induced arachidonic acid metabolism in mouse liver microsomes, suggesting that there are differences in the catalytic sites or tertiary structures of CYP1A5 and the CYP-enzyme catalyzing the TCDD-induced arachidonic acid metabolism in mouse liver. This study shows that the effects of TCDD of the profile of CYP-dependent arachidonic acid metabolities and the amounts produced in mouse liver microsomes differ from other species. The findings suggest that species differences in CYP1A catalytic activities including the metabolism of arachidonic acid may contribute to species differences in sensitivity to TCDD toxicity.

Animals↗
PubMed1998

The natural history of HIV disease in haemophilia.

Patients with haemophilia, particularly that due to factor VIII deficiency, have been exposed to a wide range of infective agents transmitted through blood products that have in other ways revolutionized their care. The most devastating of these transfusion transmitted infections has been the human immunodeficiency virus (HIV). AIDS in haemophilic patients was first described in 1982 and it has significantly reduced the life expectancy of these patients. In this article, the impact of the HIV epidemic within haemophilic patients treated with coagulation factor concentrate is discussed. The effect of age at time of exposure to HIV and the value of disease markers such as P24 antigenaemia and CD4 counts are considered in detail. The relationship between HIV disease and coexisting hepatitis C infection is described and the incidence of secondary malignancies such as lymphoma is reviewed. In this patient population the recent elucidation of the life cycle and dynamics of HIV as well as the technological advances in the development of the HIV RNA PCR assay for HIV viral load have revolutionalized the diagnosis, prognosis, management and treatment of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1998

The rate of CD4 decline as a determinant of progression to AIDS independent of the most recent CD4 count. The Italian Seroconversion Study.

The data of two cohort studies of HIV-infected individuals were used to examine whether the rate of CD4 decline is a determinant of HIV progression, independent of the most recent CD4 count. Time from seroconversion to clinical AIDS was the main outcome measure. Rates of CD4 decline were estimated using the ordinary least squares regression method. AIDS incidences were compared in individuals who had previously experienced either a steeper or a less steep rate of CD4 decline. Cox proportional hazards model including a time-dependent covariate for the rate of CD4 decline was performed. The rate of prior CD4 decline was significantly associated with the risk of developing AIDS independently from the most recent CD4 count, with a 2% increase in hazard of AIDS (P < 0.01) for a difference of 10 cells/mm3 in the estimated yearly drop in CD4 count. This finding gives scientific credit to the belief that individuals with a prior steeper CD4 decline consistently have a higher subsequent risk of developing AIDS than those with a less steep prior decline.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Myosin regulatory elements as vectors for gene transfer by intramuscular injection.

Intramuscular injection of plasmid constructs promises to be an effective way of carrying out gene therapy for muscle disorders as well as using muscle as an in vivo expression system for disorders that involve the gene product being secreted into the bloodstream. The effectiveness of this method depends on the design of the cassette used for the expression of the cDNA of the introduced gene. We tested the levels of expression achieved by a number of muscle-specific promoters and a myosin light chain enhancer when spliced to the reporter gene chloramphenicol acetyltransferase (CAT), in vitro and in vivo by injection into fast and slow muscles of the mouse. The results show that the highest levels of expression are achieved by a combination of a truncated myosin heavy chain promoter and the enhancer, and that a whole range of expression levels is obtained with the other combinations tested. The data show that a cassette based on these elements should provide efficient vectors for the introduction and expression of genes following intramuscular injection of naked DNA.

Animals↗
PubMed1998

The effect of monoclonal or ion-exchange purified factor VIII concentrate on HIV disease progression: a prospective cohort comparison.

The CD4 count has been reported to decline less rapidly in HIV-infected haemophiliacs treated with monoclonally purified factor VIII concentrates than in those using intermediate-purity concentrates. No survival advantage has been demonstrated for this effect, and it is unclear whether this effect occurs with all high-purity concentrates. Two cohorts of patients with severe haemophilia A and HIV treated with either ion-exchange-purified or monoclonally-purified concentrates were compared. The CD4 count, survival, AIDS-defining illnesses, CDC category and anti-retroviral therapy were recorded at 6-monthly intervals for 3 years following the change from intermediate to high-purity factor VIII. 116 patients were recruited, 37 of whom were treated with an ion-exchange purified factor VIII concentrate at three centres, mean (SD) age 31.1 (12.2) years, and 79 were treated with monoclonally purified factor VIII concentrate at two centres, mean (SD) age 29.8 (11.2) years. At the start of the study the median CD4 count was (monoclonal v ion-exchange) 0.30 v 0.16 x 10(9)/l. The CD4 count declined in both arms to a median of (monoclonal v ion-exchange) 0.16 v 0.08 x 10(9)/l at the final visit. Analysis of the (CD4 count)(1/2) over time, using a random coefficients model, found that the mean (SE) rates of decline were not statistically significantly different in the two treatment groups (monoclonal v ion exchange: -0.050 (0.008) v -0.034 (0.011) (CD4 count)(1/2) per year, P = 0.24). No statistically significant difference in survival (log-rank test: P = 0.33) was found. There was no difference in the proportion of individuals experiencing one or more AIDS-defining illnesses (P = 0.32) or in the proportion progressing to CDC category IV (P = 0.28) during the study. The CD4 count declined during the study at a rate similar to that previously reported in patients treated with intermediate-purity factor VIII concentrate, and there was no evidence of any difference between the two treatment groups.

Blood Component Transfusion↗
PubMed1998

Clinical experience with the use of clotting factor concentrates in oral anticoagulation reversal.

We report the clinical experience of a large Haemophilia Centre and Haemostasis Unit in reversing oral anticoagulation (OAC) using clotting factor concentrates. This is a retrospective study extending over 2 years (January 1996-December 1997). Reversal was performed using a combination of factor IX and factor VII concentrates administered by intravenous infusion. in a dose varying between 12 i.u./kg and 50 i.u./kg. We identified 20 episodes of OAC reversal in 18 patients, with a prevalence of 10 reversal episodes/1000 OAC patients/year. The median age was 77 years old (range 53-92 years). Indications for OAC reversal were divided into major bleeds (muscle haematoma [9], haematuria [3], subarachnoid haemorrhage [1], oesophageal bleeding [1], haemoptysis [1], haemarthrosis [1]); minor bleeds (extensive bruising [9], epistaxis [3], oral cavity bleeding [1]); and emergency invasive investigation (2). Pre-reversal, the international normalized ration (INR) was greater than 6.0 in 15/18 patients. Post-infusion. there was an immediate reduction in the INR towards normal (mean 1.3; range 1.1-2.3). There were no thrombotic complications or other adverse effects. The median use of factor 9 A concentrate was 2300 units/patient (range 570-4195), at a cost of 645 Pounds/patient and for factor VII concentrate 2200 units/patient (range 815-3630), at a cost of 664 Pounds/patient. Clotting factor concentrates provide a safe, rapid and effective means for OAC reversal and although expensive it is the treatment of choice in the over anticoagulated, bleeding patient.

Aged↗
PubMed1998

The changing patterns of factor VIII (FVIII) and factor IX (FIX) clotting factor usage in a comprehensive care centre between 1980 and 1994.

The annual amount of clotting factor used by patients at the Royal Free Haemophilia Centre increased significantly from 4 million iu in 1980 to over 15 million iu by 1994 (P < 0.0001). In order to assess the reasons for this increase, data on concentrate usage over this period were retrospectively collected for patients who had haemophilia or von Willebrand's disease. Only patients who were registered exclusively at the Centre were included in the study. In total, 498 patients met the inclusion criterion. The median age of the cohort on 1 January 1980 was 21 (range < 1-69) years. During the period there were 88 births and 45 deaths. The majority of patients had haemophilia A (55%). The median follow-up period per patient was 2.1 (range 0-14.8) years. Despite adjusting for increases in the number of patients and changes in body weight, statistically significant increases in clotting factor usage were detected for some subgroups of patients, in particularly for those with severe haemophilia A and B and from the late 1980s onwards, for patients with von Willebrand's disease. Two reasons for this increase in clotting factor usage were identified as being the introduction of improved products and prophylaxis. However, the increased cost of clotting factor provision that has resulted from these changes in treatment policy should not be analysed in isolation but should be balanced off against cost decreases in other areas and against increases in the effectiveness of treatment.

Comprehensive Health Care↗
PubMed1998

Quality of life during menstruation in patients with inherited bleeding disorders.

Menorrhagia is a common and major problem for patients with inherited bleeding disorders, especially vWD. Quality of life during menstruation was assessed in 99 patients with inherited bleeding disorders including vWD (n = 57), carriers of haemophilia A (n = 17), carriers of haemophilia B (n = 7) and FXI deficiency (n = 18), and comparison was performed with an age-matched control group (n = 69). A questionnaire was used that included four main sections: (i) general health, (ii) health and daily activities, (iii) dysmenorrhea and (iv) quality of life during the menstrual period. Although patients with inherited bleeding disorders felt that their health (in general) was very good, they had significantly poorer quality of life on all the scales used than controls. Thirty-nine per cent reported having cut down on the amount of time spent on work and other activities as a result of their menstruation; 47% felt that they accomplished less than they would like during this period, 38% felt that they were limited in the kind of work and other activities that they could do, and 40% found that it took extra effort to perform their work. Fifty-one per cent experienced moderate, severe or very severe dysmenorrhoea. Quality of life was statistically poorer in patients with vWD, menstrual scores > 100 according to the pictorial blood assessment chart (PBAC), those who had periods > or = 8 days and those who experienced flooding or passage of clots. In conclusion, menstruation has a negative effect on the quality of life in patients with inherited bleeding disorders especially in those with objectively confirmed menorrhagia.

Adolescent↗
PubMed1998

Towards achieving global haemophilia care--World Federation of Hemophilia programmes.

The overall purpose of the 'Decade Plan' published in 1992 was to do everything possible to make effective treatment available to people with haemophilia throughout the world. In 1990 it was estimated that there were 350,000 individuals with haemophilia worldwide, with 80% or 280,000 without treatment. By the year 2020 this may have reached the figure 440,000, or the population of Jerusalem. Earlier this century Carroll Birch reported a series of 113 patients where 82 died before their 15th year, and only six survived beyond 40. Thus as Jones has pointed out for the developing world this is a paediatric problem for the WFH to face now. The examples described in this paper illustrating the WFH programmes and the commitment of many people from the 88 member organisations worldwide as well as the doctors and scientists shows what can be done through cooperation. There is no doubt that these achievements are capitalising from the unique quality of WFH from the beginning, that is a membership which includes both those with haemophilia and their families, and those with an interest in treating haemophilia.

Health Knowledge, Attitudes, Practice↗
PubMed1998

Changes in lymphocyte subsets in human immunodeficiency virus-positive persons with < 5 CD4 T lymphocytes/mm3.

All patients seen at the Royal Free Hospital, London, who had at least one CD4 T lymphocyte count of < 5 cells/mm3 (n = 166) were prospectively followed to assess changes in their total T lymphocyte and CD8 T lymphocyte counts over time. While overall there were no clear trends towards a drop or increase in either count, persons who died during the study experienced a rapid drop in both CD8 T lymphocyte and total T lymphocyte levels in the months preceding death. Multivariate Cox proportional hazards models revealed that both the total T lymphocyte count and CD8 T lymphocyte count provided important prognostic information for survival. Despite almost a complete absence of CD4 T lymphocytes, lymphocyte subset monitoring is useful in identifying decreasing CD8 T lymphocyte levels that predict short-term prognosis.

CD4-Positive T-Lymphocytes↗
PubMed1998

Pregnancy in women with von Willebrand's disease or factor XI deficiency.

OBJECTIVE: To assess the obstetric outcome in women with von Willebrand's disease or factor XI deficiency. SETTING: Haemophilia Centre and Haemostasis Unit, The Royal Free Hospital. POPULATION: Women with von Willebrand's disease (n = 31) and with factor XI deficiency (n = 11) registered at the Royal Free Hospital Haemophilia Centre who had had a pregnancy within the previous 17 years (1980-1996), including 84 in women with von Willebrand's disease and 28 in women with factor XI deficiency. METHODS: Women were interviewed and details of the obstetric history were obtained. The records of the Haemophilia Centre and the women's maternity records were also reviewed. RESULTS: Threatened miscarriage occurred in 33% and 14% of pregnancies with von Willebrand's disease and factor XI deficiency, respectively. Excluding recurrent miscarriages, 14/68 (21%) of pregnancies with von Willebrand's disease and one pregnancy with factor XI deficiency miscarried spontaneously. There was an increased incidence of primary and secondary post-abortal bleeding complications. Factor VIII and von Willebrand factor antigen and activity levels increased significantly in pregnancy in all women apart from those with severe von Willebrand's disease. Factor XI, however, did not show any significant change. No neonatal haemorrhagic complications in association with the birth process were reported, although ventouse and difficult forceps deliveries were avoided. Extensive perineal bruising and haematoma was reported in three women with von Willebrand's disease; two of these were associated with forceps delivery. The incidence of primary postpartum haemorrhage was 18.5% in von Willebrand's disease and 16% in factor XI deficiency. Blood transfusion was required in six cases of von Willebrand's disease and two cases of factor XI deficiency. Ten of fourteen instances of primary postpartum haemorrhage occurred when maternal factor levels were < 50 IU/dL with no prophylactic treatment for labour. The incidence of secondary postpartum haemorrhage was 20% in von Willebrand's disease and 24% in factor XI deficiency. None of the women who had prophylactic treatment during labour or the puerperium suffered any significant bleeding complications. There were three neonatal bleeding complications. CONCLUSION: Pregnancy, labour and the puerperium are associated with significant bleeding problems in women with von Willebrand's disease or factor XI deficiency, but these are largely preventable. Specialist obstetric care in close liaison with the haemophilia centre is essential to minimise maternal and neonatal complications.

Abortion, Spontaneous↗
PubMed1998

Outcome of orthotopic liver transplantation in patients with haemophilia.

BACKGROUND: Many patients with haemophilia have developed cirrhosis or hepatocellular carcinoma due to transfusion acquired chronic viral hepatitis. AIMS: To assess the long term outcome of all haemophilic patients reported to have undergone orthotopic liver transplantation. METHODS: Transplant centres of patients identified by medical database search were contacted and survival data assessed by Kaplan-Meier analysis. RESULTS: Twenty six haemophilic men (median age 46 years, range 5-63 years) underwent orthotopic liver transplantation in 16 centres between 1982 and 1996. Indications for transplantation were hepatitis C cirrhosis (69%), hepatitis B with or without C cirrhosis (15%), viral hepatitis related hepatocellular carcinoma (12%), and biliary atresia (4%). Six patients (23%) were infected with human immunodeficiency virus (HIV). Postoperatively, the median time to normal clotting factor levels was 24 hours (range 0-48 hours) and exogenous clotting factors were stopped at a median of 24 hours (range 0-480 hours). Four patients (15%) had bleeding complications. The one and three year survival of HIV positive recipients (67% and 23%) was significantly poorer (p = 0.0003) than that of HIV negative recipients (90% and 83%). Coagulopathy was cured in all patients surviving more than 12 days post-transplant. Six of the 20 patients (30%) with hepatitis C cirrhosis pretransplant had evidence of disease recurrence at a mean of nine months post-transplant. CONCLUSIONS: Hepatitis C cirrhosis is the most common indication for orthotopic liver transplantation in patients with haemophilia. Transplantation results in long term cure of haemophilia but may be complicated by the effects of HIV infection or recurrent viral hepatitis.

Adolescent↗
PubMed1998

Characterization of the selectivity and mechanism of human cytochrome P450 inhibition by the human immunodeficiency virus-protease inhibitor nelfinavir mesylate.

In vitro studies with human liver microsomes and P450 probe substrates were performed to characterize selectivity and mechanism of cytochrome P450 inhibition by nelfinavir mesylate. At therapeutic concentrations (steady-state plasma concentrations approximately 4 microM), nelfinavir was found to be a competitive inhibitor of only testosterone 6beta-hydroxylase (CYP3A4) with a Ki concentration of 4. 8 microM. At supratherapeutic concentrations, nelfinavir competitively inhibited dextromethorphan O-demethylase (CYP2D6), S-mephenytoin 4-hydroxylase (CYP2C19), and phenacetin O-deethylase (CYP1A2) with Ki concentrations of 68, 126, and 190 microM, respectively. Nelfinavir did not appreciably inhibit tolbutamide 4-hydroxylase (CYP2C9), paclitaxel 6alpha-hydroxylase (CYP2C8), or chlorzoxaxone 6beta-hydroxylase (CYP2E1) activities. The inhibitory potency of nelfinavir toward CYP3A4 suggested the possibility of in vivo inhibition of this isoform, whereas in vivo inhibition of other P450s was considered unlikely. In a one-sequence crossover study in 12 healthy volunteers, nelfinavir inhibited the elimination of the CYP3A substrate terfenadine and the carboxylate metabolite of terfenadine. The 24-hr urinary recoveries of 6beta-hydroxycortisol were reduced by an average of 27% during nelfinavir treatment, consistent with CYP3A inhibition by nelfinavir. Inhibition of CYP3A4 by nelfinavir in vitro was NADPH-dependent requiring the catalytic formation of a metabolite or a metabolic intermediate. The catechol metabolite of nelfinavir (M3) was considered unlikely to be responsible for inhibition as the addition of catechol O-methyl transferase, S-adenosyl methionine, and ascorbic acid to the preincubation mixture did not protect against the loss of testosterone 6beta-hydroxylase activity. Also, the addition of M3 to human liver microsomes did not inhibit CYP3A4. Although incubations with nelfinavir showed a time- and concentration-dependent loss of CYP3A4 activity, the partial or complete recovery of enzyme activity upon dialysis indicated that inhibition was reversible. Microsomal incubations with nelfinavir and NADPH did not result in a loss of spectral P450 content compared with the NADPH control. Glutathione, N-acetylcysteine, and catalase did not attenuate CYP3A4 inhibition by nelfinavir. Collectively, these results suggest that the probable mechanism for CYP3A4 inhibition by nelfinavir is a transient metabolic intermediate or stable metabolite that coordinates tightly but reversibly to the heme moiety of the P450.

Adolescent↗