Evaluation of current methods used to analyze the expression profiles of ATP-binding cassette transporters yields an improved drug-discovery database

The development of multidrug resistance (MDR) to chemotherapy remains a major challenge in the treatment of cancer. Resistance exists against every effective anticancer drug and can develop by multiple mechanisms. These mechanisms can act individually or synergistically, leading to MDR, in which the cell becomes resistant to a variety of structurally and mechanistically unrelated drugs in addition to the drug initially administered. Although extensive work has been done to characterize MDR mechanisms in vitro, the translation of this knowledge to the clinic has not been successful. Therefore, identifying genes and mechanisms critical to the development of MDR in vivo and establishing a reliable method for analyzing highly homologous genes from small amounts of tissue is fundamental to achieving any significant enhancement in our understanding of MDR mechanisms and could lead to treatments designed to circumvent it. In this study, we use a previously established database that allows the identification of lead compounds in the early stages of drug discovery that are not ATP-binding cassette (ABC) transporter substrates. We believe this can serve as a model for appraising the accuracy and sensitivity of current methods used to analyze the expression profiles of ABC transporters. We found two platforms to be superior methods for the analysis of expression profiles of highly homologous gene superfamilies. This study also led to an improved database by revealing previously unidentified substrates for ABCB1, ABCC1, and ABCG2, transporters that contribute to MDR.

Cell fates as high-dimensional attractor states of a complex gene regulatory network

Cells in multicellular organisms switch between distinct cell fates, such as proliferation or differentiation into specialized cell types. Genome-wide gene regulatory networks govern this behavior. Theoretical studies of complex networks suggest that they can exhibit ordered (stable) dynamics, raising the possibility that cell fates may represent high-dimensional attractor states. We used gene expression profiling to show that trajectories of neutrophil differentiation converge to a common state from different directions of a 2773-dimensional gene expression state space, providing the first experimental evidence for a high-dimensional stable attractor that represents a distinct cellular phenotype.

Reproducibility of forced inspiratory and expiratory volumes after bronchodilation in patients with COPD or asthma

The aim of the present study was to assess the reproducibility of changes in forced inspiratory volumes after bronchodilator inhalation. Thirteen patients with chronic obstructive pulmonary disease (COPD) (FEV1, 32-75%pred) and 10 patients with asthma (FEV1, 43-75%pred) inhaled either 200 microg fenoterol or 200 microg oxitropium bromide or placebo, each of them on three occasions, on nine different days in a randomised, cross-over, double-blind fashion. Forced expiratory (FEV1) and inspiratory (FIV1) volumes were measured before and 30 min after inhalation. In patients with COPD, the increase in FEV1 (coefficient of variation) was 221 ml (43%) after fenoterol and 235 ml (33%) after oxitropium; changes in FIV1 were 301 ml (45%) and 360 ml (29%). In patients with asthma, FEV1 improved by 618 ml (26%) and 482 ml (25%), FIV1 by 553 ml (41%) and 475 ml (23%). In less severe COPD or asthma, the reduction in dyspnoea was associated with the improvements in both FIV1 and FEV1, but in severe COPD with the improvement in FIV1 only. The data demonstrate that, at least in terms of relative changes, the reproducibility of bronchodilator responses in terms of FIV1 is similar to that of FEV1 and they underline the assertion of FIV1 being a sensible parameter particularly in severe COPD.

[Commitment of mentally ill and community psychiatry]

The question was investigated whether during the time of building up a psychiatric department in a General Hospital the situation changes in the Mental Hospital already in evident points e.g. the rate of compulsory admissions. Two years were compared: 1984 the year before the psychiatric department was established and 1988 the year with half of the number of planned beds built up in the psychiatric department. The number of admissions to the Mental Hospital was cut in half. The total sum of compulsory admissions to the Mental Hospital as well as to the psychiatric department was reduced from 255 (1984) to 148 (1988). Already in this time of building up the psychiatric department the compulsory admitted, the gerontopsychiatric patients and the foreigners were over proportional represented among the patients in the department compared to the Mental Hospital. The often presumed selection did not take place.

Photodynamic effects of new silicon phthalocyanines: in vitro studies utilizing rat hepatic microsomes and human erythrocyte ghosts as model membrane sources

Photodynamic therapy (PDT) of cancer is a modality that relies upon the irradiation of tumors with visible light following selective uptake of a photosensitizer by the tumor tissue. There is considerable emphasis to define new photosensitizers suitable for PDT of cancer. In this study we evaluated six phthalocyanines (Pc) for their photodynamic effects utilizing rat hepatic microsomes and human erythrocyte ghosts as model membrane sources. Of the newly synthesized Pc, two showed significant destruction of cytochrome P-450 and monooxygenase activities, and enhancement of lipid peroxidation, when added to microsomal suspension followed by irradiation with approximately 675 nm light. These two Pc named SiPc IV (HOSiPcOSi[CH3]2[CH2]3N[CH3]2) and SiPc V (HOSiPc-OSi[CH3]2[CH2]3N[CH3]3+I-) showed dose-dependent photodestruction of cytochrome P-450 and monooxygenase activities in liver microsomes, and photoenhancement of lipid peroxidation, lipid hydroperoxide formation and lipid fluorescence in microsomes and erythrocyte ghosts. Compared to chloroaluminum phthalocyanine tetrasulfonate, SiPc IV and SiPc V produced far more pronounced photodynamic effects. Sodium azide, histidine, and 2,5-dimethylfuran, the quenchers of singlet oxygen, afforded highly significant protection against SiPc IV- and SiPc V-mediated photodynamic effects. However, to a lesser extent, the quenchers of superoxide anion, hydrogen peroxide and hydroxyl radical also showed some protective effects. These results suggest that SiPc IV and SiPc V may be promising photosensitizers for the PDT of cancer.

Chemotherapeutic study on Yoshida sarcoma ascites cells implanted into the glandular stomach of rats. Monotherapy with 5-fluorouracil, methyl-CCNU, mitomycin C, adriamycin, and cytosine arabinoside, and combination therapy with respective two-drug combinations

The chemotherapeutic activity of five cytostatic drugs was investigated experimentally in monotherapy and in two-drug combinations, using Yoshida sarcoma cells implanted into the wall of the glandular stomach of Sprague-Dawley rats. In monotherapy, the antibiotic agent mitomycin C and the nitrosourea methyl-CCNU exhibited the highest cytotoxic activity in this tumor model. In combination therapy, the combination of these two drugs was superior to all the other therapeutic schemes tested. In general, the results demonstrate a marked superiority of combination therapy in comparison with monotherapy.

Induction of tumors of the forestomach in rats by oral application of N-methyl-N'-nitro-nitrosoguanidine

After 12 oral applications of 80 mg/kg MNNG as a suspension in 30% aqueous ethanol at weekly intervals, 98 Sprague-Dawley rats died with multiple tumors of the forestomach after a medium latency period of 226 days. Histological examination showed generalized papillomatosis developing into keratinizing squamous cell carcinomas with infiltrative growth in 88/98 (89%) animals. Tumorigenic lesions in the glandular stomach ware only observed in 3/98 rats. In two of these animals, mucosal adenocarcinomas were found and in the third a leiomyosarcoma. In about 30% of the animals treated with MNNG, degenerative liver changes were found, especially single cell and focal necroses, cystic alterations, and bile-duct proliferations.

On the significance of severe local reactions to Hymenoptera stings

Of 317 patients with hypersensitivity to Hymenoptera stings forty had severe local reactions (SLR) only, fifty-nine reported severe local reactions before their first and seven after their last systemic reaction (SR). The probability to develop a life threatening systemic reaction when restung after a severe local reaction was calculated to be about 5%. In 80% of the patients with severe local reactions only, hypersensitivity to either bee or yellow jacket venom could be demonstrated by skin tests and/or RAST. A fair correlation of skin test and RAST results was observed. In patients with severe local reactions hyposensitization therapy with venoms is not generally indicated. In exceptional patients whose allergy is proven by skin tests or RAST and who are at a high risk of being restung, hyposensitization may be considered.