Matrix isolation FT-IR and theoretical DFT/B3LYP spectrum of 1-naphthol.

The FT-IR spectrum of 1-Naphthol isolated in an argon matrix is performed and compared to the infrared spectra calculated at the DFT (B3LYP)/6-31+G(d) level for cis-1-Naphthol and trans-1-Naphthol rotamers in order to clarify the existence of both rotamers in the standard temperature. Comparison of the computed and the experimental matrix spectra reveals the presence in 1-Naphthol argon matrices in the standard temperature of both cis and trans rotameric forms of 1-Naphthol, the last predominating. The relative stability of the trans-1-Naphthol rotamer has also been supported by a fit comparison between the difference of predicted total energy (ETC) of both rotamers of 0.00195 a.u. corresponding to 5.12 kJ mol(-1) and the variation of the standard free Gibbs energy of rotamerization (ΔGr°) of 5.06 kJ mol(-1). Almost all 51 active vibrational modes of 1-Naphthol have been assigned. The stretching vibration of the OH group (νOH) appears to be the unique vibrational mode distinguishing the cis-1-NpOH rotamer from the trans-1-NpOH rotamer in FT-IR spectrum.

Infrared spectra of proton transfer complexes of the cycleanine alkaloid in solid state.

Proton transfer complexes obtained between the cycleanine alkaloid and hydrogen chloride, hydrogen bromide and nitric acids have been investigated by infrared spectroscopic technique between 4000 and 400 cm(-1) in KBr. The vibrational perturbations brought about by proton transfer complex formation, discussed in terms of preferred site of interaction, show that the proton of the inorganic acids is transferred to cycleanine through one of its N sites.

Infrared spectra of 6-thioguanine tautomers. An experimental and theoretical approach.

Both amino-thiol N9H and amino-thiol N7H tautomeric forms of 6-thioguanine have been identified in approximately equal abundance in infrared studies of these molecules isolated in the hydrophobic environment of an argon matrix at 12 K. The relative concentrations of the amino-thiol N9H and amino-thiol N7H ([SH, N9H]/[SH, N7H] = K(N9H-N7H) = 1.00 +/- 0.02) are estimated from the observed relative infrared absorbances. From these relative concentrations, the difference in the Gibbs free energy of these two tautomers (deltaG500(N9H-N7H) = -0.012 +/- 0.005 kJ mol(-1) have been estimated. The infrared and Raman spectra of 6-thioguanine in solid state are also discussed in terms of hydrogen bonding and stacking interactions in the crystal which are not considered in the calculation. In an effort to interpret the experimental results, ab initio calculation of the infrared spectrum has been made for the amino-thione N7H tautomer at 3-21G level. Comparison with experimental spectra is of some help in the assignment of the infrared and Raman spectra for 6-thioguanine in the solid state.

Recurrent growth factor starvation promotes drug resistance in human leukaemic cells.

Multi-drug resistance can be induced by various environmental stresses including an exposure to chemical drugs and X-ray irradiation. In addition, hypo-nutritive conditions are known to promote multi-drug resistance in solid tumours. To understand the importance of nutritive conditions in the development of drug resistance in non-solid tumours and to know whether a transient malnutrition could induce a permanent reduction in drug sensitivity, leukaemic cells were transiently cultured under growth factor-starved conditions. Granulocyte-macrophage colony-stimulating factor-dependent human leukaemic MO7e cells were cultured in the absence of granulocyte-macrophage colon-stimulating factor for 2 weeks, during which the majority of the cells died, and the minor viable cells were expanded in the presence of granulocyte-macrophage colon-stimulating factor for following 1 week. This procedure was repeated three times, and the surviving cells were cloned by limiting dilution. These clones underwent G1 arrest in the absence of granulocyte-macrophage colon-stimulating factor, while parental cells underwent apoptosis. Interestingly, activities of the downstream targets of granulocyte-macrophage colon-stimulating factor receptor were regulated in a granulocyte-macrophage colon-stimulating factor-independent manner, indicating that the ligand-independent activation of granulocyte-macrophage colon-stimulating factor receptor had not taken place. Moreover, the 4--7-fold increases in IC(50) for etoposide and the 2--6-fold increase in IC(90) for doxorubicin was observed. Furthermore, Bcl-2 protein expression was significantly up-regulated in the clones while no significant changes in Bax, Bcl-(xL), P-glycoprotein and Hsp70 protein expression and no consistent changes in p53 expression were detected. We propose that recurrent growth factor starvation, which may occur in vivo when stromal function is damaged after intensive chemotherapy or bone marrow occupation by malignant cells, causes selection of drug resistant leukaemia cells that will expand when the growth factor supply recovers.

Involvement of apoptosis-inducing factor during dolichyl monophosphate-induced apoptosis in U937 cells.

Dolichyl monophosphate (Dol-P) has been found to induce apoptosis in human leukemia U937 cells. During this apoptotic execution, the increase of plasma membrane fluidity (5-20 min), caspase-3-like protease activation (2-4 h), chromatin condensation and DNA ladder formation (3-4 h) were observed successively. Here, we report that reduction in mitochondrial transmembrane potential and translocation of apoptosis-inducing factor (AIF) are early events (1-3 h) in the apoptotic process induced by Dol-P in U937 cells. The AIF was concentrated around nuclei and partly translocated to the nuclei, which was confirmed by immunocytochemistry using specific anti-AIF antibody. Both caspase-8 and caspase-3 inhibitors blocked only DNA fragmentation but not mitochondrial processes, AIF migration and chromatin condensation. These results indicate that mitochondrial changes are an early step in the apoptosis induced by Dol-P and AIF is one of the important factors which induce chromatin condensation in nuclei.

Induction of apoptosis in human hematopoietic U937 cells by granulocyte-macrophage colony-stimulating factor: possible existence of caspase 3-like pathway.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induced apoptosis in human hematopoietic U937 cells by itself and in a synergistic manner with tumor necrosis factor (TNF). GM-CSF-induced apoptosis was not inhibited by caspase inhibitors YVAD-CMK, DEVD-CHO and z-VAD-FMK, under the condition that these inhibitors potently suppressed TNF-induced apoptosis. Both GM-CSF and TNF induced caspase 3-like activity in this cell line though the time course was distinct between two cytokines, and combined stimulation of cells with GM-CSF plus TNF induced additive or synergistic activation of caspase 3-like activity. Amount of immunoreactive cleaved forms of caspase 3 recognized by specific antibody was completely dissociated with its enzymatic activity when the cells were stimulated with GM-CSF, but not with TNF. These results indicate that GM-CSF induces apoptosis of U937 cells via unknown pathway, which seems to be mediated by caspase 3-like activity, yet not caspase 3 itself, resistant to the caspase inhibitors, and synergistically interacts with conventional caspase 3 pathway of TNF. Possible involvement of caspases 1 and 8 (-like activity) but not caspase 7 in this pathway was also suggested.

Bcl-2 down-regulation causes autophagy in a caspase-independent manner in human leukemic HL60 cells.

To understand the roles of bcl-2 for the survival of leukemic cells, we constructed human leukemic HL60 transformant lines in which full length bcl-2 antisense message was conditionally expressed by a tetracycline-regulatable expression system. Cell growth was completely inhibited after antisense message induction and massive cell death was induced. Electron microscopic examinations show that cells died by autophagy, but not by apoptosis. The morphology and the function of mitochondria remained intact: neither the reduction in mitochondrial membrane potential nor the nuclear translocation of AIF, a mitochondrial protein that translocates to nuclei in cases of apoptosis, was observed. Caspase inhibitors did not rescue bcl-2-antisense-mediated autophagy. Thus, bcl-2 is essential for leukemic cell survival and its down-regulation results in autophagy. Cell Death and Differentiation (2000) 7, 1263 - 1269.

Signal transduction pathways in normal human monocytes stimulated by cytokines and mediators: comparative study with normal human neutrophils or transformed cells and the putative roles in functionality and cell biology.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL) -3 induced tyrosine phosphorylation of 92-kDa protein in normal human monocytes. We identified this 92-kDa protein as STAT5, but not as STATs1, 3, and 6 nor c-fes and vav protooncogene products, and demonstrated its translocation to the nucleus, enhancement of specific DNA binding capacity, and potentiation of trancriptional activity by GM-CSF. N-formyl-methionyl-leucyl-phenylalanine (FMLP) and phorbol myristate acetate (PMA) induced tyrosine phosphorylation of 42- and 44-kDa proteins, which were identified as extracellular signal-regulated kinase (ERK), in human monocytes. In marked contrast to neutrophils and MO7e cells, GM-CSF did not induce tyrosine phosphorylation and activation of ERK in monocytes. Among upstream signaling molecules of ERK, Shc was constitutively associated with Grb2 and was not tyrosine-phosphorylated by GM-CSF and FMLP, and Sos1 and c-Raf-1 were not phosphorylated by GM-CSF, IL-3, TNF, and FMLP in monocytes, whereas all these signaling molecules were affected and/or utilized by GM-CSF in MO7e cells. In contrast to neutrophils, p38 was constitutively phosphorylated and agonist-dependent phosphorylation and activation was not detected in human monocytes. Superoxide release stimulated by FMLP was inhibited partially by PD98059 or SB203580, a specific inhibitor of ERK or p38 pathway, and was almost completely inhibited by the combination of both inhibitors, whereas PMA-induced superoxide release was resistant to these two inhibitors in monocytes. PD98059 inhibited GM-CSF-dependent proliferation of MO7e cells. Present results indicate trancriptional roles of STAT5 and functional roles of ERK and/or p38 in normal human monocytes stimulated by physiological receptor-mediated agonists GM-CSF and FMLP. Possible roles of ERK in proliferation of transformed cells were also suggested.

Cooperative stimulatory effects of tumor necrosis factor and granulocyte-macrophage colony-stimulating factor on the particular respiratory burst activity in human neutrophils: synergistic priming effect on concanavalin A-induced response, no interactive priming effect on the chemotactic peptide-induced response and additive triggering effect.

Tumor necrosis factor (TNF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) rapidly primed human neutrophils for enhanced superoxide (O2-) release, and membrane depolarization stimulated by chemotactic peptide (N-formyl-methionyl-leucyl-phenylalanine), interleukin 8, concanavalin A (Con A) and ionomycin. Combined stimulation of human neutrophils with the optimal concentrations of TNF plus GM-CSF showed no additive or synergistic effects according to the subsequent stimuli and within the parameters tested. Particularly, a high synergistic priming effect of these two cytokines was observed when Con A was used as a triggering agonist of O2- release. The priming of human neutrophils with the optimal concentrations of TNF plus G-CSF, however, always resulted in the same effect as TNF alone. TNF and GM-CSF triggered O2- release directly in human neutrophils for prolonged time periods, and combined stimulation of human neutrophils with the optimal concentrations of TNF plus GM-CSF triggered an added amount of O2- release. TNF and GM-CSF by themselves induced an increase in cytoplasmic pH (intracellular alkalinization), an important signaling event for functional activation of neutrophils, though combined stimulation of human neutrophils with the optimal concentrations of the two cytokines had no additive effects on cytoplasmic pH. The present results show cooperative interaction between TNF and GM-CSF in their stimulatory effects on particular functions in human neutrophils, and these synergistic effects are probably mediated via a mechanism distal to or independent of intracellular alkalinization.

Room temperature-induced apoptosis of Jurkat cells sensitive to both caspase-1 and caspase-3 inhibitors.

We recently reported that HL-60 cells underwent apoptosis when exposed to room temperature (RT) (21 degrees C). RT-induced apoptosis of HL-60 cells is inhibited by the caspase-1 inhibitor (YVAD-CMK), but not by the caspase-3 inhibitor (DEVD-CHO). In this study, we studied RT-induced apoptosis in 15 human cell lines of hematopoietic lineage and found that the Jurkat cell line also responded to RT by a different apoptotic process. RT-induced apoptosis of Jurkat cells was attenuated by YVAD-CMK as well as DEVD-CHO. Increased caspase activity on DEVD-AMC, which was inhibited by both YVAD-CMK and DEVD-CHO added to the cell culture, was also detected. The involvement of caspase-3 itself, however, was not recognized by Western blot analysis. In contrast, the processing of caspase-3 was observed in the apoptotic HL-60 cells. These data implicate the presence of the redundant processes of apoptosis induced by RT treatment.

Tyrosine phosphorylation of p38 but not extracellular signal-regulated kinase in normal human neutrophils stimulated by tumor necrosis factor: comparative study with granulocyte-macrophage colony-stimulating factor.

We investigated the cytokine-specific involvement of two members of the microtubule-associated protein kinase family, extracellular signal-regulated kinase (ERK)(1 and 2) and p38, in normal human neutrophils. Both tumor necrosis factor (TNF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) induced tyrosine phosphorylation of a 42-kDa protein in human neutrophils, though the time course of its phosphorylation and its band pattern in electrophoresis differed for each of the cytokines. In addition, GM-CSF, but not TNF, induced a mobility shift of 42-kDa ERK2 in human neutrophils. By using immunoprecipitation followed by immunoblotting, we clarified that GM-CSF, but not TNF, induced tyrosine phosphorylation of ERK2 and that TNF, but not GM-CSF, induced tyrosine phosphorylation of p38. Results of a combined stimulation study showed that tyrosine phosphorylation of ERK2 and that of p38 do not interfere or interact with each other at least in human neutrophils. These results indicate cytokine specific involvement and an independent activating system of ERK and p38 in normal human neutrophils stimulated by two cytokines which share many biological activities in these cells.

Simultaneous determination of D- and L-amino acids in the nervous tissues of crustaceans using precolumn derivatization with (+)-1-(9-fluorenyl)ethyl chloroformate and reversed-phase ion-pair high-performance liquid chromatography.

After the derivatization of D- and L-amino acids with (+)-1-(9-fluorenyl)ethyl chloroformate, nineteen amino acids were separated into their D- and L-enantiomers and from other physiological amino compounds by reversed-phase ion-pair high-performance liquid chromatography. The separation was performed by three separate runs differing in mobile phase compositions and gradient profiles. Tyrosine, tryptophan and cysteine could not be detected because of their weak reactions with the derivatization reagent. Of seven D-amino acids found in the crustacean nervous tissues and eyes, D-alanine, D-arginine and D-aspartate were the most abundant and widely distributed.

Selecting CD-ROM databases for nursing students: a comparison of MEDLINE and the Cumulative Index to Nursing and Allied Health Literature (CINAHL).

With the introduction of the Cumulative Index to Nursing and Allied Health Literature (CINAHL) on CD-ROM, research was initiated to compare coverage of nursing journals by CINAHL and MEDLINE in this format, expanding on previous comparison of these databases in print and online. The study assessed search results for eight topics in 1989 and 1990 citations in both databases, each produced by SilverPlatter. Results were tallied and analyzed for number of records retrieved, unique and overlapping records, relevance, and appropriateness. An overall precision score was developed. The goal of the research was to develop quantifiable tools to help determine which database to purchase for an academic library serving an undergraduate nursing program.

Human urinary excretion of L-histidine-related compounds after ingestion of several meats and fish muscle.

1. After oral administration of the muscle of skipjack tuna, about 90% of ingested anserine (Ans) was excreted quickly into urine as Ans (8%) and pi-methylHis (82%), indicating the fast decomposition of Ans into pi-methylHis. This was also the case for chicken muscle ingestion. 2. After eel muscle ingestion, carnosine (Car) excretion was only 1% of the ingested whereas almost no increase was found in His, a constituent of Car, indicating the re-utilization of this essential amino acid. Similar results were also obtained from beef and pork ingestion. 3. In all cases, the urinary excretion of these compounds reached a maximum within 7 hr after ingestion and returned to the level of meat-free diet within 40 hr.

Major buffering constituents in animal muscle.

1. Among the muscles of six fish species, three mammals, and a bird, white muscle of skipjack tuna showed the highest buffering capacity (BC) in the pH range 6.5-7.5, followed by the muscle of little-piked whale, chicken pectoralis minor, and mackerel white muscle. 2. Contribution of low-molecular weight components to the muscle BC was as high as 48-96%, while the contribution of muscle proteins was below 50%. 3. Histidine-related dipeptides and inorganic phosphate were found to be major buffering constituents in muscle. 4. The dipeptides accounted for the BC differences found between the species and muscle types.

Effect of Yeast Extract and Vitamin B(12) on Ethanol Production from Cellulose by Clostridium thermocellum I-1-B.

Addition to media of yeast extract, a vitamin mixture containing vitamin B(12), biotin, pyridoxamine, and p-aminobenzoic acid, or vitamin B(12) alone enhanced formation of ethanol but decreased lactate production in the fermentation of cellulose by Clostridium thermocellum I-1-B. A similar effect was not observed with C. thermocellum ATCC 27405 and JW20.