The spectrum of spontaneous mutations caused by deficiency in proteasome maturase Ump1 in Saccharomyces cerevisiae

Ump1 is responsible for maturation of the catalytic core of the 26S proteasome. Dysfunction of Ump1 causes an increase in the frequency of spontaneous mutations in Saccharomyces cerevisiae. In this study we analyze the spectrum of mutations occurring spontaneously in yeast deficient in Ump1 by use of the SUP4-o system. Single base substitutions predominate among the mutations analyzed (73 of the 91 alterations examined). Two major classes are GC to TA transversions and GC to AT transitions ( approximately 50 and approximately 30% of base substitutions, respectively). Besides base substitutions, almost all the major types of sequence alterations are represented. The specificity and distribution of mutations occurring in the ump1 strain are unique compared to the spectra previously established for other yeast mutators. However, the profile of mutations arising in this strain is similar to that observed in wild type. The same similarity has previously been reported for yeast deficient in Mms2, a protein involved in Rad6-dependent postreplication DNA repair (PRR). The specificity of the mutator effect caused by ump1 is discussed in light of the proposed role of the proteasome activity in the regulation of the PRR mechanisms.     

Effects of Expanded Cardiac Rehabilitation on Psychosocial Status in Coronary Artery Disease with Focus on Type D Characteristics

Type D personality has been shown to increase the risk for cardiovascular events in patients with coronary artery disease (CAD). We investigated the effects of expanded cardiac rehabilitation on type D score and psychosocial characteristics in 224 CAD patients randomised to either expanded cardiac rehabilitation (stress management, increased physical training, stay at a “Patient Hotel” after discharge and cooking sessions), or routine rehabilitation. Follow-up was 1 year. At baseline patients with a high type D score [patients in the upper quartile of type D score (Q4) i.e., type D patients] had a lower sense of coherence (p < 0.001), a lower quality of life (p < 0.001), more depressive symptoms (p < 0.001) and increased anxiety (p < 0.001) as compared to patients with a low type D score (Q1). During follow-up, type D patients (Q4) randomised to intervention had significant decrements in type D-score (p < 0.01), depression and anxiety (p < 0.05) and an increment in quality of life scores (p < 0.001). Quality of life was also improved in control type D patients (Q4; p < 0.01) but no significant changes were seen in type D score, depression or anxiety. Expanded cardiac rehabilitation reduces type D score, anxiety and depressive symptoms, and improves the quality of life in type D patients.     

Anti-tumor action of tumor necrosis factor against Bomirski Ab melanoma in hamsters

Introduction: Tumor necrosis factor (TNF) is a cytokine able to exert anti-tumor activity in various models and modes of applications. However, the exact mechanism mediating the in vivo anti-tumor effect of TNF has not yet been clarified. Materials and Methods: The effects of intratumoral injection of rat TNF into hamsters bearing Bomirski Ab amelanotic melanoma, a fast growing tumor of high metastatic potential, were tested. Subcutaneous injections of the anti-angiogenic compound TNP-470 allowed analysis of its influence on the effects of TNF administration. Results: TNF application resulted in a significant inhibition of tumor growth and changes in metastasis pattern. Accelerated hemorrhagic necrosis was also observed, indicating the effect of the cytokine on tumor vessels. Moreover, the synergistic anti-tumor effect of TNF and anti-angiogenic agent TNP-470 suggested a cooperative activity of both substances on tumor vasculature. Microscopically, the effect of TNF injections was expressed by an increase in the amount of tumor cells with nuclear pyknosis and karryorrhexis. In vitro assays indicated a direct cytotoxic effect of TNF against Ab melanoma cells, most probably as an outcome of apoptosis. Intratumoral application of TNF also caused some modulation of cytokine response in melanoma-bearing hamsters as evidenced by increased levels of IL-6 in blood serum. Conclusions: This study established Bomirski Ab melanoma as a useful model for complex analysis of the anti-tumor activity of TNF.     

Effect of Microenvironmental pH Modulation on the Dissolution Rate and Oral Absorption of the Salt of a Weak Acid – Case Study of GDC-0810

Purpose

The purpose of this work is to investigate the effect of microenvironmental pH modulation on the in vitro dissolution rate and oral absorption of GDC-0810, an oral anti-cancer drug, in human.

Methods

The pH-solubility profile of GDC-0810 free acid and pH_max of its N-Methyl-D-glucamine (NMG) salt were determined. Precipitation studies were conducted for GDC-0810 NMG salt at different pH values. GDC-0810 200-mg dose NMG salt tablet formulations containing different levels of sodium bicarbonate as the pH modifier were tested for dissolution under the dual pH-dilution scheme. Three tablet formulations were evaluated in human as a part of a relative bioavailability study. A 200-mg dose of GDC-0810 was administered QD with low fat food.

Results

Intrinsic solubility of GDC-0810 free acid was found to be extremely low. The pH_max of the NMG salt suggested a strong tendency for form conversion to the free acid under GI conditions. In vitro dissolution profiles showed that the dissolution rate and extent of GDC-0810 increased with increasing the level of sodium bicarbonate in the formulation. The human PK data showed a similar trend for the geometric mean of C_max and AUC_0-t for formulations containing 5%, 10%, and 15% sodium bicarbonate, but the difference is not statistically significant.

Conclusion

Incorporation of a basic pH modifier, sodium bicarbonate, in GDC-0810 NMG salt tablet formulations enhanced in vitro dissolution rate of GDC-0810 via microenvironmental pH modulation. The human PK data showed no statistically significant difference in drug exposure from tablets containing 5%, 10%, and 15% sodium bicarbonate.