Molecular analysis integrating different pathways associated with androgen-independent progression in LuCaP 23.1 xenograft

After therapeutic hormone deprivation, most prostate cancer (PrCa) cells develop androgen-independent (AI) growth. PrCa is highly heterogeneous and multifocal, suggesting that several molecular processes or pathways may be contributing to AI. The human LuCaP 23.1 xenograft model retains clinical hallmarks of PrCa, including heterogeneous growth, PSA production, androgen-responsiveness and progression to AI. In this work, we studied the effect of androgen depletion (castration) on the growth of LuCaP 23.1 xenografts. A total of 100 nude mice were implanted and analysed for their growth profiles before and after castration. By 11 and 15 weeks, tumours were harvested and assessed for molecular marker expression specific for PrCa. Prior to castration we found 37 fast growing (FG) tumours (948.9+/-76.9 mm(3)) and 63 slow growing (SG) tumours (229.6+/-18.4 mm(3)), a previously undescribed result for this PrCa model. Quantitative RT-PCR showed that in comparison to SGs, FGs contained high HER1, uPA and thymidilate synthetase (TS) expression with low levels of 5alpha-reductase 2 mRNA. All FG tumours progressed rapidly to AI growth 5 weeks after castration (FG-P). In SG castrated tumours, 66% of tumours (SG-P) showed retarded progression (by 12 weeks) to AI, whereas 34% responded to castration (SG-R). Molecular analysis permitted us to define distinct molecular profiles integrating different pathways associated with AI progression. FG-P, and a subgroup of SG-P tumours, presented significantly high levels of peptidylglycine alpha-amidating monooxygenase (PAM), HER1, HER2, TS, and uPA mRNA, all of which correlated with AR expression. The second subgroup of SG-P tumours showed overexpression of the antiapoptotic gene Bcl-2. A third subgroup of SG-P tumours showed significant expression of hypoxia-related gene (adrenomedullin) after castration. This work permitted to define distinct molecular profiles related to different AI growth in the LuCaP 23.1 xenograft.     

Technetium-99m-Labeled N-(2-Hydroxypropyl) Methacrylamide Copolymers: Synthesis,Characterization, and in Vivo Biodistribution

PURPOSE: To synthesize novel technetium-99m (99mTc)-labeled N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers and characterize the effect of charge and molecular weight on their biodistribution in SCID mice. METHODS: Electronegative and neutral 7-kDa, 21-kDa, and 70-kDa HPMA copolymers containing a 99mTc chelating comonomer, bearing N-omega-bis(2-pyridylmethyl)-L-lysine (DPK), were synthesized by free-radical precipitation copolymerization. The copolymers were labeled via 99mTc tricarbonyl chelation to DPK-bearing comonomer. They were characterized by side-chain content, molecular weight, molecular weight distribution, radiochemical purity, and labeling stability. Scintigraphic images were obtained during the first 90 min and at 24 h postintravenous injection in SCID mice. At 24 h, organ radioactivity was determined from necropsy tissue counting. RESULTS: 99mTc-labeled HPMA copolymers showed greater than 90% stability over a 24-h challenge with cysteine and histidine. Scintigraphic images and the necropsy data showed that the negatively charged copolymers were eliminated from the body significantly faster than the neutral copolymers in a size-dependent manner. CONCLUSIONS: To facilitate clinical scintigraphic imaging, stable chelation of 99mTc may be achieved by incorporation of a DPK-bearing comonomer into the HPMA backbone. Electronegative and neutral 99mTc-labeled HPMA copolymers of 7, 21, and 70 kDa show significant variation in organ biodistribution in SCID mice. 99mTc-labeled HPMA copolymers could be used as diagnostic agents and to study pharmacokinetics of delivery systems based on these copolymers.     

Echocardiographic screening for congenital heart disease: a randomized study

OBJECTIVES: To assess the effectiveness and potential cost of an echocardiographic screening program for congenital heart disease (CHD). PATIENTS AND METHODS: Between 01/11/94 and 28/02/98 there were 9697 deliveries in The Royal Maternity Hospital Belfast. Mothers were randomized before delivery. 4875 infants were allocated to the scan group, while 4822 were assigned to clinical assessment alone. High-risk infants were considered separately. Cases of CHD detected before hospital discharge were documented. The annual cost of screening was estimated and the time to accurate diagnosis in each group was assessed. RESULTS: During the study 124 scan allocated infants and 50 controls were identified as having significant CHD before hospital discharge. With a minimum of 3 years follow-up there were 27 additional late diagnoses in controls and 1 in scanned infants. During a single year of the study the mean time to complete diagnosis was 2 days for scanned cases and 110 in controls. The projected cost of screening for all infants was 22 Pounds/infant for the first year. CONCLUSIONS: Adding echocardiography to clinical examination greatly enhances early detection of CHD. Although screening is expensive, once established it may reduce the cost of unnecessary outpatient referrals.     

Modeling biotransformation reactions by combined quantum mechanical/molecular mechanical approaches: from structure to activity

An overview of the combined quantum mechanical/molecular mechanical (QM/MM) approach and its application to studies of biotransformation enzymes and drug metabolism is given. Theoretical methods to simulate enzymatic reactions have rapidly developed during the last decade. In particular, QM/MM methods provide detailed insights into enzyme catalyzed reactions, which can be extremely valuable in complementing experimental research. QM/MM methods allow the reacting groups in the active site of an enzyme to be studied at a quantum mechanical level, while the surrounding protein and solvent is included at a classical (and computationally less expensive) molecular mechanical level. Existing QM/MM implementations vary in the level of interaction between the QM and MM regions and in the way the partitioning into QM and MM regions is setup. Some general considerations concerning reaction modeling are discussed and a number of QM/MM studies related to drug metabolism are described. These studies illustrate that theoretical modeling of important metabolic reactions provides detailed insights into mechanisms of reaction and specific catalytic effects of enzyme residues as well as explaining variation in rates of conversion of different metabolites. Such information is essential in the development of methods to predict metabolism of drugs and to understand metabolic effects of genetic polymorphism in biotransformation enzymes.     

A double-blind,placebo-controlled trial of sertraline for depressive symptoms in patients with stable,chronic schizophrenia

There have been no studies specifically examining the efficacy of selective serotonin reuptake inhibitor antidepressants for the symptoms of depression in schizophrenia. This study aimed to determine the efficacy and safety of sertraline as a treatment for depressive symptoms in patients with stable, chronic schizophrenia. The Beck Depression Inventory (BDI) was used as the principal outcome measure and other measures of depressive symptoms as secondary outcome measures. Twenty-six patients were entered into a double-blind, placebo-controlled, 8-week trial of sertraline and were included in the intent-to-treat (ITT) analysis (13 in each group). Eight patients in the sertraline group and 12 in the placebo group completed at least four weeks in the study and were considered to have had adequate treatment. On the ITT analysis, the mean score on the BDI fell 14.5% for the sertraline group and 5.6% for the placebo group (p > 0.05); the mean score on the Hamilton Depression Rating Scale (HDRS) fell 16.99% for the sertraline group and 8.3% for the placebo group (p > 0.05). When the analysis was repeated for those who had received adequate treatment, the mean BDI score fell by 28% for the sertraline group and 6% for the placebo group (p = 0.1); the mean HDRS score fell 31% for the sertraline group and 8.6% for the placebo group (p = 0.02). On the Clinical Global Impression-Improvement Scale, 10 of the 13 patients on sertraline improved against four of the 13 in the placebo group (p = 0.05). Sertraline-treated patients showed a significant improvement on the anxiety/ depression subscale of the BPRS on ITT analysis (F = 10.1, p = 0.004). There was no significant effect on negative or positive symptoms. Sertraline was well tolerated. The results suggest that sertraline is useful as a treatment for depressive symptoms in schizophrenia.     

Squamous cell carcinoma and transitional cell carcinoma arising in bladder augmentations

Tumours arising in bowel-augmented bladders are rare. Usually these tumours are adenocarcinomas that occur along the anastomotic line. We present two unusual tumours, squamous cell carcinoma and transitional cell carcinoma, that occurred in bladder augmentations. We also emphasize the need for regular cystoscopic surveillance.