Lung cancer and cyclooxygenase-2

Lung cancer is by far the leading cause of cancer-related death. Overall survival is poor and has not improved substantially over the last half century. It is clear that new approaches are needed and these should include prevention, screening for early detection, and novel treatments based on our understanding of the molecular biology of this disease. Recently attention has been drawn to the role of the cyclooxygenase (COX) enzyme and its involvement in tumorigenesis. Investigations have documented two isoforms, COX-1 and COX-2, encoded by different genes. COX-1 is constitutively expressed in most tissues and appears to be responsible for the production of prostaglandins mediating normal physiologic functions, such as the maintenance of gastric mucosa and regulation of renal blood flow. In contrast, COX-2 is normally undetectable in most tissues, and is induced by cytokines, growth factors, oncogenes, and tumor promoters. A growing body of evidence indicates COX-2 plays a key role in lung cancer, and can serve as a potential marker of prognosis in this disease. Furthermore, the recent availability of COX-2 inhibitor medications offers a unique opportunity to interfere with the development of lung cancer and the progression of metastasis. Because COX-2 inhibitors have been demonstrated to interfere with tumorigenesis, the COX-2 enzyme may be an attractive target for therapeutic and chemoprotective strategies in lung cancer patients.     

Oscillapeptin J,a new grazer toxin of the freshwater cyanobacterium Planktothrix rubescens

Oscillapeptin J (1), a new and highly potent crustacean grazer toxin, was isolated from the axenic cyanobacterium Planktothrix rubescens, which frequently forms blooms in freshwater lakes. Chemical and spectroscopic analyses, including high resolving MS and two-dimensional NMR, were used to elucidate the compound's structure as a depsiheptapeptide of the oscillapeptin type. Strict application of a bioassay-guided isolation procedure proved this compound to be one of the major causative agents (besides [d-Asp(3),(E)-Dhb(7)]microcystin-RR) of the acute grazer toxicity of P. rubescens from Lake Zürich. The LC(50) value of oscillapeptin J as determined for the freshwater crustacean Thamnocephalus platyurus was 15.6 microM.     

Developmental changes of parameters for astrogliosis during cultivation of purified cerebral astrocytes from newborn rats

Astrogliosis is a common phenomenon seen in most neuropathological changes of the central nervous system. Several in vitro models have been used to study the mechanisms and conditions for the induction of astrogliosis, however many do not take into account that the metabolic and structural characteristics of astrocytes change with time in culture. Thus, it appears difficult to attribute changes of, e.g., GFAP to the normal change in vitro as opposed to additional changes due to an astrogliotic reaction. The present study was therefore undertaken to characterize these developmental changes in purified astroglial secondary cultures during cultivation to provide a basis for further investigations of astrogliosis in vitro. During 6 weeks of cultivation (3-43 days) GFAP (ELISA) increased much more (22-fold) than the cell number (2.5-fold) and the total protein (3.5-fold). The GFAP/protein ratio increased during the first 4 weeks of cultivation and reached a plateau thereafter, which was accompanied by a significant increase of GFAP mRNA (Northern blot). At the ultrastructural level (transmission electron microscopy) gliofilaments in the perinuclear region as well as in the cell processes of 4-day-old astrocytes showed a dispersed pattern, whereas an accumulation of gliofilaments was found in 39-day-old cells, which formed large aggregated bundles localized mostly in the cell processes. Our results show that in vitro astrocytes undergo developmental changes in their accumulation of GFAP and intermediate filaments which reach a stable steady state after 4 weeks in culture. These 'normal' developmental changes will have to be taken into account, when experiments with variations of the level of GFAP are performed. Stable culture conditions for experimentation appear to be present after 4 weeks in culture.     

Intrathecal synthesis of monocyte chemoattractant protein-1 (MCP-1) in amyotrophic lateral sclerosis: further evidence for microglial activation in neurodegeneration

Autopsy studies and animal experiments suggest that microglial inflammation contributes to the pathogenesis of amyotrophic lateral sclerosis (ALS). Monocyte-chemoattractant protein (MCP-1) might play an important role in microglial recruitment. We studied MCP-1 levels in sera and cerebrospinal fluid of 29 ALS patients and compared the results with 11 control patients with tension headache. The MCP-1 level was determined using enzyme-linked immunosorbent assays (ELISA). A significant increase in cerebrospinal fluid MCP-1 level but not serum level was seen in the patients with ALS compared to the control subjects. These results suggest that cerebrospinal fluid MCP-1 activity may be a sensitive marker for neuroinflammation in ALS useful for monitoring treatment trials in ALS.     

Dry powders of stable protein formulations from aqueous solutions prepared using supercritical CO(2)-assisted aerosolization

We report on the use of a new supercritical carbon dioxide-assisted aerosolization coupled with bubble drying technology to prepare stabilized, dry, finely divided powders from aqueous protein formulations. In this study, the feasibility of this new technology was tested using two model proteins, lysozyme and lactate dehydrogenase (LDH). In the absence of excipients, lysozyme was observed to undergo perturbations of secondary structure observed by solid-state infrared spectroscopy. In the presence of sucrose, this unfolding was minimized. Lysozyme did not, however, undergo irreversible loss of activity, as all lysozyme powders generated by supercritical CO(2)-assisted aerosolization (with or without excipients) regained almost complete activity on reconstitution. The more labile LDH suffered irrecoverable loss of activity on reconstituting after supercritical CO(2)-assisted aerosolization and bubble drying in the absence of carbohydrate stabilizers. LDH could be stabilized throughout the nebulization, drying, and rehydration processes with the addition of sucrose, and almost complete preservation of activity was achieved with the further addition of a surface active agent, such as Tween 20, to the aqueous formulation prior to processing.     

Sirolimus: continuing the evolution of transplant immunosuppression

OBJECTIVE: To review the pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and economic issues associated with sirolimus, the most recent immunosuppressive agent approved for kidney transplantation. DATA SOURCES: A MEDLINE search (1966-June 2000) was completed to identify primary and review articles. In addition, abstracts from recent meetings on transplantation were reviewed for information and research on sirolimus. STUDY SELECTION AND DATA EXTRACTION: Blinded, randomized, controlled studies were the goal, but, as with most newly approved immunosuppressive agents, a significant amount of information on sirolimus is not available in this optimal form. All articles were assessed and all pertinent information was incorporated in this review. DATA SYNTHESIS: Sirolimus is structurally related to the immunosuppressive agent tacrolimus, and retains a pharmacokinetic and drug interaction profile similar to that of the calcineurin inhibitors, cyclosporine and tacrolimus. However, the novel mechanism of action of sirolimus differs significantly from these agents, as does its adverse effect profile. The most significant adverse reaction is hyperlipidemia. Clinical experience with sirolimus has allowed transplant centers to expand its use into other areas of transplantation as well as certain autoimmune disorders. CONCLUSIONS: The definitive role of sirolimus will continue to be determined; however, sirolimus offers an excellent addition to the transplant immunosuppression armamentarium.