Expression changes of CYP2A and CYP3A in microsomes from pig liver and cultured hepatocytes

The P450 enzymes of the liver are responsible for the metabolism of a wide range of chemical compounds, and hepatocytes are used in pharmacological and toxicological in vitro tests. Thus, it is important to know how stable these enzymes are in culture. We measured the activity of CYP2A and CYP3A in microsomes isolated from both pig liver and primary pig hepatocyte cultures, together with the apoprotein concentration using Western blotting. The CYP2A activity and apoprotein concentration decreased rapidly; only about 5 percent remained after 48 hr incubation, whereas the CYP3A activity and apoprotein concentration was constant. CYP3A was induced 3 times after exposure to rifampicin, whereas neither rifampicin nor pyrazole could induce CYP2A. The hepatocytes were also incubated with varying concentration of FCS and autologous serum, however without effect on the stability of CYP2A, nor did different concentrations of growth hormone and testosterone added to the cultures have any effect.     

Recominant Expression and Immunological Characterization of House Dust Mite Allergen Der P 1

The cysteine protease Der p1 from dust mite of the genus Dermatophagoides pteronyssinus is a major type I allergen. About 80% of house dust mite (HDM) allergic individuals are reactive to this protease in standard assays for detection of IgE. A curative treatment for atopic allergy is immunotherapy (IT) with HDM extracts which are complex mixtures occasionally resulting in anaphylactic reactions. Novozymes focuses on developing a recombinant variant of Der p1 which exhibit lowered risk of IgE-mediated allergic reactions, while maintaining its ability to trigger proper Th-cell responses. This may provide a safer alternative for specific IT of HDM allergy. A secreted recombinant form of pro-Der p 1 expressed by Saccharamyces cerevisiae was obtained by fusion of the pro-enzyme to a fungal signal peptide. The N -glycosylation site of Der p1 was mutated resulting in a deglycosylated pro-enzyme with a molecular mass of 35 kDa. Protein purification procedure was developed to obtain nearly pure Der p1 protein followed by determination of concentration by active-site-titration with the cysteine protease inhibitor E64. The deglycosylated recombinant pro-Der p 1 revealed immunologic similarity to the native Der p 1 molecule when compared in basophile histamine release, IgE-binding assays and T-cell proliferation assays. By in silico epitope mapping of a modelled 3-dimensional structure of Der p1, five putative IgG and IgE epitopes were predicted. By protein engineering, the predicted epitopes were removed one by one in Der p1 and screening for hypoallergenic variants was performed.     

The transformation of primary and established mouse mammary epithelial cells by p21-ras is concentration dependent

We constructed a retroviral vector (pZSR) which is capable of simultaneously expressing the neomycin resistance gene and the viral ras oncogene. Primary mammary gland epithelial cells were prepared from mid-pregnant mice and infected with this virus. Cell lines with epithelial cell characteristics could be established with a low frequency. High expression of p21 v-ras was observed in these cells. They are tumorigenic and form soft agar colonies dependent on the presence of EGF and insulin in the growth medium but progress to hormone independent growth at higher passage numbers. A cloned cell line of non-tumorigenic, established mammary epithelial cells (NOG8) was also infected with the v-ras expressing virus. Individual cell clones expressing increasing amounts of p21 v-ras were selected. The level of p21 v-ras expression directly influences the morphology of the epithelial cells in culture, determines their cloning efficiency in soft agar and their tumorigenicity.     

Mortality and incidence of cancer among sewage workers: a retrospective cohort study.

To study the incidence of and mortality from cancer among sewage workers a retrospective analysis was performed on a cohort of 656 men employed for at least one year at any one of 17 Swedish sewage plants during the years 1965-86. Assessment of exposure was done by classification of work tasks. Lower than expected total mortality (standardised mortality ratio (SMR) = 0.75, 95% confidence interval (95% CI) 0.58-0.97) and cardiovascular mortality (SMR = 0.61, 95% CI 0.39-0.91) was found. This was interpreted as a result of the healthy worker effect. For all cancers combined the mortality (SMR = 1.08, 95% CI 0.68-1.67) and morbidity (SMR = 1.02, 95% CI 0.72-1.38) were comparable with those of the general population. There were increased incidences for brain tumours (SMR = 2.19, 95% CI 0.45-6.39), gastric cancers (SMR = 2.73, 95% CI, 1.00-5.94), and renal cancers (SMR = 1.68, 95% CI = 0.35-4.90). For lung cancer the risk was reduced (SMR = 0.70, 95% CI 0.15-2.05). Allowance for a latency period of 10 years from the start of exposure did not change the pattern. Logistic modelling was used to search for exposure-response relations. In a logistic model with the confounder age forced in, renal cancer had a significant positive relation with a weighted sum of employment times, where the weights describe the classification of exposure. No exposure-response relations were found for brain tumors or gastric cancers. The increased risks are based on small numbers of cases. A future follow up will add more conclusive power to the study. Specific exposures need to be identified to allow for a better dose-response analysis.     

Escitalopram in the treatment of depressed elderly patients.

OBJECTIVE: Management of depression in elderly patients presents a significant medical challenge, and there is a need for further clinical trials. The authors examined the efficacy and tolerability of escitalopram and fluoxetine versus placebo in the treatment of elderly patients with major depressive disorder (MDD). METHODS: This was an 8-week, randomized, double-blind comparison of the efficacy and tolerability of escitalopram (10 mg/day) and fluoxetine (20 mg/day), to placebo in elderly patients with MDD. The prospectively defined primary efficacy parameter was the change from baseline in mean Montgomery-Asberg Depression Rating Scale (MADRS) total score at endpoint, using last observation carried forward. RESULTS: The intent-to-treat set comprised 517 patients; the escitalopram group included 173 patients; fluoxetine, 164 patients; and placebo, 180 patients. Mean age was 75 years, with a range of 65 to 93. Formally, this was a "failed study" (i.e., neither active treatment was superior to placebo), and the efficacy results should, therefore, be interpreted with caution. On the basis of the primary efficacy parameter, fluoxetine showed significantly lower efficacy than both escitalopram and placebo, which were not significantly different from each other. Rates of withdrawal because of adverse events/lack of efficacy were: placebo (2.8%/4.4%, respectively), escitalopram (9.8%/1.7%, respectively), and fluoxetine (12.2%/1.8%, respectively). No single adverse event occurred at an incidence > or =10% in escitalopram-treated patients. CONCLUSIONS: Both escitalopram and fluoxetine were well tolerated by elderly patients with MDD. Neither demonstrated superior efficacy on primary endpoint versus placebo.