Development of extended multidrug resistance in HL60 promyelocytic leukaemia cells

Summary. In an attempt to mimic clinical conditions for the treatment of leukaemia, the HL60 promyelocytic cell line was treated for 18 h with low, clinically relevant, levels of the anthracycline epirubicin and the Vinca alkaloid vinblastine. The resulting drug-resistant sublines not only expressed P-glycoprotein and the MDR phenotype but were also cross-resistant to chlorambucil, methotrexate but were also cross-resistant to chlorambucil, methotrexate and cisplatinum, and had increased resistance to radiation. Development of resistance was associatted with an aberrant differentiation phenotype with decreased expression of myeloid antigens and expression of glycophorin A. an antigen normally associated with erythroid differentiation. The ability of HL60 cells to terminally differentiate in response to all- trans -retinoic acid (vitamin A acid) was lost in the sublines. These results suggest that either a single novel mechanism is responsible for multiple drug resistance or the initial response to drug treatment is the co-induction of multiple mechanisms. These cells and the method by which they were generated therefore provide a clinically relevant model for the study of the initial events in the development of not only multidrug resistance but also the extended multiple drug resistance usually encountered in the treatment of leukaemia.     

Onabotulinumtoxin type A improves lower urinary tract symptoms and quality of life in patients with human T cell lymphotropic virus type 1 associated overactive bladder

Aim

To evaluate the efficacy of the onabotulinum toxin type A in the treatment of HTLV-1 associated overactive bladder and its impact on quality of life (QoL).

The Italian Implantable Cardioverter-Defibrillator Registry. A survey of the national activity during the years 2001-2003.

BACKGROUND: In recent years several trials demonstrated the efficacy of implantable cardioverter-defibrillator (ICD) therapy for sudden cardiac death prevention and total mortality reduction in particular high-risk groups of patients. The aim of this review was to report the main epidemiological data and the most important clinical characteristics of patients enrolled in the Italian ICD Registry in the years 2001-2003. METHODS: The Italian ICD Registry--official member of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC)--collects 85% of the data concerning the national ICD implantation activity, based on the European Implantable Defibrillator form (EURID). Data are validated for quality of information and uniqueness at the moment of data entry and in successive steps at the time of the annual analysis. RESULTS: The number of ICDs implanted in Italy has been continuing to increase during the last years according to the general trend in European and non-European countries: 2400 in the year 2001, 3934 in the year 2002, and 5318 in the year 2003. The number of ICDs per million of inhabitants in Italy was 42.1 in the year 2001 (+11.8% with respect to 2000), 69.0 in the year 2002 (+63.9% with respect to 2001), and 93.3 in the year 2003 (+35.2% with respect to 2002). The number of implanting centers increased progressively from 273 in the year 2001 to 304 in the year 2002, and 340 in the year 2003. The median age of patients treated with ICD implantation was 67 years in the years 2001-2002, 68 years in the year 2003. The prevalence of male patients was significantly higher (79.3% in 2001, 82.3% in 2002, and 81.4% in 2003). The main indication was syncope (25.5, 29.3, and 32.9% in the years 2001, 2002, and 2003, respectively), followed by palpitations (17.7, 18.5, and 16.4% in the years 2001, 2002, and 2003, respectively), and cardiac arrest (10.0, 13.1, and 16.5% in the years 2001, 2002, and 2003, respectively). The use of ICD in patients considered at risk but without history of sustained ventricular tachycardia had a 3-fold increase during the 3 years, from 6.4% in 2001 to 18.2% in 2003. Ventricular tachycardia was the main arrhythmia in 50.4 to 55.0% of cases, ventricular fibrillation in 13.5 to 18.1%, both in 4.1 to 6.5%. The vast majority of patients presented at the enrolment either a mild or severe reduction in ejection fraction (30 to 50%, < 30%). Amiodarone was administered alone or in combination with antiarrhythmics in 29.7 to 40.0% of patients. Single-chamber ICDs were implanted in the years 2002 and 2003 in 45.7 and 39.2% of patients, dual-chamber ICDs in 34.9 and 32.4%, biventricular ICDs in 19.4 and 28.4%, respectively. CONCLUSIONS: The ICD implantation rate in Italy increased significantly in the period 2001-2003, similarly to the trend in the other western countries and following the publication of controlled studies in the field of primary and secondary prevention of sudden cardiac death. The Italian ICD Registry showed during the last 3 years an important increase in prophylactic ICD utilization. A sophisticated ICD, including dual-chamber pacing or cardiac resynchronization therapy, was chosen in a high percentage of patients.     

A study of conformational restraints on reactivity of human PR3-specific autoantibodies (ANCA) facilitated through protein folding manipulations of a new recombinant proteinase 3 protein

Proteinase 3 (PR3)-specific antineutrophil cytoplasmic autoantibodies (PR3-ANCA) recognize conformational epitopes on PR3. This study evaluates PR3-ANCA target epitopes utilizing a novel recombinant PR3 (rPR3) produced to accommodate manipulations of the N-terminal domain. The rPR3 molecule contains an N-terminus six histidine tag, which can be removed by enterokinase (EK) cleavage of an adjacent EK cleavage site. Once cleaved the remaining amino acids correspond to the mature N-terminus of PR3. This rPR3 can be manipulated to produce three variant forms: tagged rPR3^+his, EK-cleaved (his-tag removed) rPR3^{? his}, and EK-cleaved, denatured/refolded rPR3^{? his/dr} (the proteolytically active form). Patients with clinically positive PR3-ANCA titers (n = 40) were confirmed for reactivity against purchased native PR3 in our system. Controls included 29 healthy volunteers and 34 MPO-ANCA patients. All PR3-ANCA sera samples tested were reactive with one or more forms of the recombinant protein (greater than mean ELISA OD 405 + 2 SDs of controls). Of significance, three sera were reactive with non-active forms only and three others were more reactive with rPR3^{? his/dr} than with native PR3. The results of our evaluation of PR3-ANCA sera for reactivity against the three forms of our rPR3 protein uniquely exemplify the diverse array of epitopes within the PR3-ANCA population. This new recombinant form of PR3 should provide a suitable approach to mapping ANCA epitopes using site-directed mutagenesis.     

Metabolic transitions at menopause: In post-menopausal women the increase in serum uric acid correlates with abdominal adiposity as assessed by DXA

Objectives

The present study aimed to investigate any associations between parameters of body fat mass distribution and levels of serum uric acid (sUA), a well-documented cardiovascular risk factor, among non-obese women ranging from pre- to post-menopausal status.

Methods

In this cross-sectional population-based study we assessed body fat distribution by dual-energy-X-ray absorptiometry (DXA), and sUA levels in 101 pre- and 134 post-menopausal non-obese apparently healthy women.

Results

Multivariate stepwise regression analysis revealed that sUA was independently associated to the indicators of overall fatness, i.e. body mass index (β = 0.339, p < 0.001) and DXA-assessed total and percentage body fat (β = 0.366, p < 0.001 and β = 0.412, p < 0.001, respectively), only among post-menopausal women. Within this sample subset, trunk (i.e. central) fat mass emerged as a strong predictor of sUA (β = 0.408, p < 0.001), after taking the potential confounders (including body mass index) into account.

Conclusion

Central fat accumulation was found to be independently associated with higher sUA levels among non-obese women in post- but not among those in pre-menopause.