alpha 1-Antichymotrypsin in lung secretions is not an effective proteinase inhibitor

This paper presents evidence that alpha 1-antichymotrypsin in lung secretions is not effective as an inhibitor of chymotrypsin-like enzymes. First, lung secretion samples inhibited more cathepsin G on a one-to-one molar basis than could be accounted for by the alpha 1-antichymotrypsin present. Second, the major cathepsin G inhibitory capacity of sputum was in gel filtration fractions that corresponded to a low molecular weight (10,000-15,000) and contained immunoreactive antileucoprotease. Third, although alpha 1-antichymotrypsin purified from plasma was almost fully active against cathepsin G, that purified from lung lavage retained less than 15% of its inhibitory function. Immunoblotting following sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that alpha 1-antichymotrypsin in plasma and lung secretions are of similar molecular size and no enzyme-alpha 1-antichymotrypsin complexes could be detected in sputum or bronchoalveolar lavage fluids. However, in contrast to the alpha 1-antichymotrypsin purified from plasma, the lavage protein gave a broad elution profile following anion-exchange chromatography.     

Binding cooperativity in phage lambda is not sufficient to produce an effective switch

In the wild-type phage λ, binding of CI to O_R2 helps polymerase bound to P_RM transition from a closed to open complex. Activators on other promoters increase the polymerase-DNA binding energy, or affect both the binding energy and the closed-open transition probability. Using a validated mathematical model, we show that these two modes of upregulation have very different effects on the promoter function. We predict that if CI₂ bound to O_R2 produced equal increase in RNAP-DNA binding constant (compared to wild-type increase in the closed-open transition probability), the lysogen would be significantly less stable.     

Teniposide is not effective in chronic lymphocytic leukemia

Teniposide has been evaluated in a phase II clinical trial in chronic lymphocytic leukemia (CLL). Among 16 consecutive patients with CLL entered in the study and treated with Teniposide, 100 mg/m2 weekly, no objective response was observed. Toxicity was generally mild and mainly hematologic. Teniposide at this dosage and schedule is an inactive drug in CLL.     

Malat1 is not an essential component of nuclear speckles in mice

Malat1 is an abundant long, noncoding RNA that localizes to nuclear bodies known as nuclear speckles, which contain a distinct set of pre-mRNA processing factors. Previous studies in cell culture have demonstrated that Malat1 interacts with pre-mRNA splicing factors, including the serine- and arginine-rich (SR) family of proteins, and regulates a variety of biological processes, including cancer cell migration, synapse formation, cell cycle progression, and responses to serum stimulation. To address the physiological function of Malat1 in a living organism, we generated Malat1-knockout (KO) mice using homologous recombination. Unexpectedly, the Malat1-KO mice were viable and fertile, showing no apparent phenotypes. Nuclear speckle markers were also correctly localized in cells that lacked Malat1. However, the cellular levels of another long, noncoding RNA--Neat1--which is an architectural component of nuclear bodies known as paraspeckles, were down-regulated in a particular set of tissues and cells lacking Malat1. We propose that Malat1 is not essential in living mice maintained under normal laboratory conditions and that its function becomes apparent only in specific cell types and under particular conditions.     

Oestradiol is effective in stimulating 3H-thymidine incorporation but not on proliferation of breast cancer cultured cells

The growth of numerous human oestrogen target cell lines is said to have been stimulated by oestradiol. We studied the action of this hormone on the growth of two human cancer cell lines originating from endometrium (GUS), and from breast (FAM). Oestradiol was inactive on endometrial cell multiplication as well as on their tritiated thymidine uptake, but in FAM breast cancer cells, we noticed a discrepancy between tritiated thymidine uptake and actual cell proliferation: there was a 40% increase in DNA precursor uptake, but no change in either the number of cells or in their DNA content, both of which were verified by two different methods. Therefore, an actual increased nuclear (autoradiographic) uptake of thymidine did take place in oestrogenized cells, associated with an increase of incorporation into DNA (a rise of radioactivity in the acid-insoluble materials), but finally there was no greater total DNA increase in the whole treated population than in control cells. Then we examined the metabolism of tritiated thymidine in oestradiol-treated FAM cells. We extracted the radioactive thymine nucleotides and characterized them chromatographically: the oestradiol caused an increase in the labelling of deoxythymine monophosphate (TMP). How these results are consistent with both unmodified cell count and whole DNA content is discussed.     

GABA is an effective immunomodulatory molecule

In recent years, it has become clear that there is an extensive cross-talk between the nervous and the immune system. Somewhat surprisingly, the immune cells themselves do express components of the neuronal neurotransmitters systems. What role the neurotransmitters, their ion channels, receptors and transporters have in immune function and regulation is an emerging field of study. Several recent studies have shown that the immune system is capable of synthesizing and releasing the classical neurotransmitter GABA (γ-aminobutyric acid). GABA has a number of effects on the immune cells such as activation or suppression of cytokine secretion, modification of cell proliferation and GABA can even affect migration of the cells. The immune cells encounter GABA when released by the immune cells themselves or when the immune cells enter the brain. In addition, GABA can also be found in tissues like the lymph nodes, the islets of Langerhans and GABA is in high enough concentration in blood to activate, e.g., GABA-A channels. GABA appears to have a role in autoimmune diseases like multiple sclerosis, type 1 diabetes, and rheumatoid arthritis and may modulate the immune response to infections. In the near future, it will be important to work out what specific effects GABA has on the function of the different types of immune cells and determine the underlying mechanisms. In this review, we discuss some of the recent findings revealing the role of GABA as an immunomodulator.     

Tamoxifen,an anticancer drug,is an activator of human aldehyde dehydrogenase 1A1

The modulation of aldehyde dehydrogenase (ALDH) activity has been suggested as a promising option for the prevention or treatment of many diseases. To date, only few activating compounds of ALDHs have been described. In this regard, N‐(1,3‐benzodioxol‐5‐ylmethyl)?2,6‐dichlorobenzamide has been used to protect the heart against ischemia/reperfusion damage. In the search for new modulating ALDH molecules, the binding capability of different compounds to the active site of human aldehyde dehydrogenase class 1A1 (ALDH1A1) was analyzed by molecular docking, and their ability to modulate the activity of the enzyme was tested. Surprisingly, tamoxifen, an estrogen receptor antagonist used for breast cancer treatment, increased the activity and decreased the K_m for NAD⁺ by about twofold in ALDH1A1. No drug effect on human ALDH2 or ALDH3A1 was attained, showing that tamoxifen was specific for ALDH1A1. Protection against thermal denaturation and competition with daidzin suggested that tamoxifen binds to the aldehyde site of ALDH1A1, resembling the interaction of N‐(1,3‐benzodioxol‐5‐ylmethyl)?2,6‐dichlorobenzamide with ALDH2. Further kinetic analysis indicated that tamoxifen activation may be related to an increase in the K_d for NADH, favoring a more rapid release of the coenzyme, which is the rate‐limiting step of the reaction for this isozyme. Therefore, tamoxifen might improve the antioxidant response, which is compromised in some diseases. Proteins 2015; 83:105–116. © 2014 Wiley Periodicals, Inc.     

Differential LEF1 and TCF4 expression is involved in melanoma cell phenotype switching

Recent observations suggest that melanoma cells drive disease progression by switching back and forth between phenotypic states of proliferation and invasion. Phenotype switching has been linked to changes in Wnt signalling, and we therefore looked for cell phenotype-specific differences in the levels and activity of β-catenin and its LEF/TCF co-factors. We found that while cytosolic β-catenin distribution is phenotype-specific (membrane-associated in proliferative cells and cytosolic in invasive cells), its nuclear distribution and activity is not. Instead, the expression patterns of two β-catenin co-factors, LEF1 and TCF4, are both phenotype-specific and inversely correlated. LEF1 is preferentially expressed by differentiated/proliferative phenotype cells and TCF4 by dedifferentiated/invasive phenotype cells. Knock-down experiments confirmed that these co-factors are important for the phenotype-specific expression of M-MITF, WNT5A and other genes and that LEF1 suppresses TCF4 expression independently of β-catenin. Our data show that melanoma cell phenotype switching behaviour is regulated by differential LEF1/TCF4 activity.     

Chocolate,an effective means of oral drug delivery in rats

Oral gavage is an important procedure for drug discovery and efficacy studies using rodents. However, there are welfare issues related to the use of the method by inexperienced persons or for long-term studies. The authors describe an effective method of administering drugs to rats by mixing the drug with chocolate to provide a consistent and reliable method of oral drug delivery to large groups of rats for a long period of time.     

Mouse alpha 1-protease inhibitor is not an acute phase reactant

Mouse plasma contains two major protease inhibitors, alpha 1-protease inhibitor (alpha 1-PI) and contrapsin, which have high affinity for bovine trypsin. Systemic injury, such as turpentine-induced inflammation, did not change the plasma concentration of alpha 1-PI, but increased that of contrapsin by 50%. The concentration of hepatic alpha 1-PI mRNA was determined by Northern blot hybridization and was not significantly affected by the acute phase reaction. J.M. Frazer, S.A. Nathoo, J. Katz, T.L. Genetta, and T.H. Finley [1985) Arch. Biochem. Biophys. 239, 112-119) have reported a threefold increase of mRNA for the elastase specific alpha 1-PI but this increase was not demonstrated by the present study. The mRNAs for known mouse acute phase plasma proteins were, however, stimulated severalfold by the same treatment. These results indicate that in the mouse, as opposed to human, alpha 1-PI is not an acute phase reactant.     

Electric computerization is an effective method in molecular-biological investigations

Characteristics of electronic computers with respect to their use in molecular-biological investigations are briefly described. Several examples of using electronic computers in conformational investigations, in studies on the structure of biopolymers, chromatography, optico-spectral investigations, etc. are listed.