Delayed methotrexate elimination in a patient with primary central nervous system lymphoma: A case report.

WHAT IS KNOWN AND OBJECTIVE: Methotrexate (MTX) is an important agent for the treatment of primary central nervous system lymphomas (PCNSL) but needs to be given in big doses by intravenous infusions to achieve therapeutic concentrations in the cerebrospinal fluid. However, co-administration with many drugs may delay the excretion of MTX which may cause serious adverse effects if the serum concentration exceeds 0.1 µmol/L 72 h after an intravenous infusion. CASE SUMMARY: A 67-year-old Japanese female with PCNSL was treated with high-dose MTX-based chemotherapy. The serum MTX concentration 72 h post-infusion was 0.153 µmol/L when she was taking levofloxacin (LVFX) but <0.1 µmol/L 72 h after 4 subsequent infusions when she was not taking LVFX. She was given many other drugs but the timing of the short course of LVFX and the fact that ciprofloxacin also delays MTX excretion suggests that LVFX was the cause. WHAT IS NEW AND CONCLUSION: Co-administration of LVFX may delay the excretion of MTX. Therefore, serum concentrations of MTX should be monitored to help prevent and improve the management of potentially serious MTX drug-drug interaction.

Regular budding modes in a zooxanthellate dendrophylliid Turbinaria peltata (Scleractinia) revealed by X-ray CT imaging and three-dimensional reconstruction.

The zooxanthellate dendrophylliid coral, Turbinaria peltata (Scleractinia), exhibit various growth forms that increase the photoreception area through the development of coenosteum skeletons. Because it is difficult to make detailed observations of the internal structures, we visualized inner skeletal structures using nondestructive microfocus X-ray computed tomography (CT) imaging. After removal of the coenosteum skeletons from the X-ray CT images, three-dimensional 3D-models were reconstructed for individual corallites. Regular budding was observed from the 3D-model and cross-sectional images as follows: 1) lateral corallites occurred only near the two primary septa on one side, apart from a directive primary septum with distinct polarity; 2) the budding occurred upward at acute angles; and 3) these regular structures and polarity were repeated throughout growth with every generation. Even in zooxanthellate dendrophylliids, the same budding modes as observed in azooxanthellate equivalents control the colonial growth. These characteristics provide clues for understanding the mechanisms that regulate the shapes of modular marine organisms.

Internal skeletal analysis of the colonial azooxanthellate scleractinian Dendrophyllia cribrosa using microfocus X-ray CT images: underlying basis for its rigid and highly adaptive colony structure.

Dendrophyllid Scleractinia exhibit a variety of colonial morphologies, formed under the strict constraints on (1) budding sites, (2) orientations of the directive septa of offsets, (3) inclination of budding direction, and (4) those constraints in every generation. Dendrophyllia cribrosa exhibits a sympodial dendroid form, characteristically large coralla, and occasional fusions of adjacent branches within the same colony. Adjacent corallites are bound and supported by coenosteum skeleton. This study examined the inner skeletal structures at the junctions of fused branches using a non-destructive microfocus X-ray computed tomography (CT) imaging approach, and considered the reasons for the large colonial sizes and their adaptive significance. Three-dimensional reconstructions of two-dimensional X-ray CT images reveal that individual corallites are not directly connected in fused parts. Additionally, no completely buried individuals were found within fused skeleton. When adjacent branches approach one another, constituent corallites change their growth directions to avoid collisions between the branches. The adjacent branches fuse without a reduction in the number of constituent corallites, leading to the establishment of reticular and rigid colonial structures. In addition, a nearly even distribution of individuals on the colony surface facilitates efficient intake of nutrients. Thus, the growth of large D. cribrosa colonies involves avoidance of collision between constituent individuals, the reinforcement of colonial structure, and efficient uptake of nutrients. These observations provide insights on the dynamics of interrelationships between colony-making mechanisms and the adaptive strategies required under habitat conditions such as specific current activities.

[Circadian rhythms and effects of anesthesia on plasma natriuretic peptide levels in rats].

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are circulating hormones secreted predominantly in patients with hypertension or congestive heart failure. To obtain background data on plasma ANP and BNP levels in rats, we investigated the circadian rhythms and effects of anesthesia on these peptides. To determine the circadian rhythms, plasma samples from thirty rats were collected by non-anesthesia (decapitation) at six time points every fourth hour. To determine the effects of anesthesia, plasma samples from thirty-two rats were collected under diethyl ether, pentobarbital or urethane anesthesia. The plasma ANP and BNP levels were determined using a radioimmunoassay. The plasma ANP levels were high from the evening to early morning, while the plasma BNP levels were relatively low at 2:30 AM. The difference in the BNP levels was statistically significant. The plasma BNP levels were relatively high when the rats were anesthetized using urethane. These results suggest that blood collection should be performed between 10:30 AM to 2:30 PM to determine plasma ANP and BNP. The use of pentobarbital is also recommended for toxicological studies in rats.

Induction of apoptosis by morphine in human tumor cell lines in vitro.

Most previous studies of the induction of tumor cell apoptosis by morphine have been conducted with concentrations very much higher than those used clinically. An investigation of the ability of morphine to induce apoptosis at its clinical concentration (10(-8) M) was therefore undertaken. Cytotoxicity was tested by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, induction of early apoptosis and necrosis by fluorescence-activated cell sorter (FACS) analysis with Annexin V and propidium iodide (PI), activation of caspase -2, -3, -8 and -9 by cleavage of specific substrates, DNA fragmentation by agarose gel electrophoresis, radical intensity and O2- scavenging activity by ESR spectroscopy. Millimolar concentrations of morphine showed higher cytotoxicity against human tumor cell lines (HL-60, A549, MCF7) than against normal human cells (HGF, HPC, HPLF). The clinical concentration of morphine produced early apoptotic markers in HL-60 and A549 cells whereas it induced higher numbers of necrotic cells in MCF7 cells, both in a naloxone-sensitive manner. The clinical concentration of morphine failed to activate any caspase species and induced only trace amounts of internucleosomal DNA fragmentation, in contrast to cytotoxic concentrations of morphine. Morphine, with a C-3 hydroxyl group, showed higher cytotoxicity and O2- scavenging activity than codeine, in which the hydroxyl group at C-3 was replaced with a methoxy group, suggesting the involvement of a radical-mediated reaction. The present report may offer new strategies for treatment and prevention of cancer using a clinical concentration of morphine not only as an anti-nociceptive, but also as an apoptosis or necrosis inducer.

[Propofol suppresses the responses in hypoglossal nerve activity to hypercapnic-hypoxic stimulation].

BACKGROUND: Upper airway obstruction and inadequate ventilation often arise during sedation and anesthesia by propofol. To estimate the influence of propofol (PP) on respiratory control, we studied its effect on the neural activity and the respiratory response caused by a brief (60 sec) respiratory arrest (RA) manifesting in the hypoglossal nerve (HG) and the phrenic nerve (PN) in rabbits. METHODS: Experiments were performed on adult rabbits vagotomized, paralyzed and ventilated artificially with 50% N2O, 50% oxygen and 0.5% sevoflurane. We evaluated and compared the effects of PP on the peak amplitude (AMP) and the root mean square (RMS) of HG and PH, and respiratory cycle (Tc). RESULTS: PP depressed HG activity more than PH activity, and increased Tc in a dose related manner, with 0.25 mg x kg(-1) x min(-1) continuous infusion, propofol soon began to reduce both AMPs without any remarkable changing in Tc. AMP&RMS-HG were reduced to about 35% and AMP&RMS-PN to 80% of control. Administration of propofol 1.5 mg x kg(-1) x min(-1) vanished the activity of HG in all animals. RA made a mixed hypercapnic and hypoxic condition and induced RA response which was characterized by raised AMPs, augmented RMSs (deltaAMPs, deltaRMSs) in activity of both nerves activity and lengthened Tc (deltaTc). PP depressed RA response in HG dose-dependently, but did not do so in PN. Significant depressions in cardiovascular effects with tested dosage of PP occurred, but the values were kept in physiological ranges. CONCLUSIONS: These results suggest that propofol induces respiratory depression by its inhibitory effect on the neural regulation of respiration, especially on the maintenance system of upper airway patency and the reflex related to the chemosensitive upper airway patency control.

[Effect of flumazenil on hypoglossal and phrenic nerves activities in rabbits].

BACKGROUND: Upper airway obstruction and inadequate ventilation often arise during sedation and anesthesia by benzodiazepines (Bz). Flumazenil antagonizes these effects of active benzodiazepines on the central nervous system. To estimate the influence of flumazenil on the endogenous Bz system related respiratory control, we studied the effect of flumazenil and diazepam on the neural activity and the respiratory response caused by a brief (60 sec) respiratory arrest (RA) manifested in the hypoglossal nerve (HG) and the phrenic nerve (PH) activities in rabbits. METHODS: Experiments were performed on adult rabbits which were vagotomized, paralyzed and artificially ventilated with 50% N2O, 50% oxygen and 0.5% sevoflurane. We evaluated and compared the effects of the sequential administrations of flumazenil and diazepam on the peak amplitude (AMP) as well as the root mean square (RMS) of HG and PH, and respiratory cycle (Tc). RESULTS: Flumazenil by itself increased HG activity more than PH activity with no influence on Tc. But it was not dose-related. Previous administration of flumazenil in total dose of 0.25 mg x kg(-1) could not prevent the anticipated respiratory depression caused by diazepam 2.0 mg x kg(-1). These depressions are greater in HG activity than in PH activity. Additional flumazenil 0.15 mg x kg(-1) following the administration of diazepam promptly reversed these inhibitory effects on HG activity beyond the control level. The same dose of flumazenil, however, did not reverse PH activity sufficiently. RA response was characterized by raised AMPs and augmented RMSs (deltaAMPs, deltaRMSs) with marked prolongation in Tc (deltaTc). Flumazenil and diazepam did not seem to have any influence upon these RA responses. There was a significant change in cardiovascular parameters with the tested dosages of flumazenil and diazepam, but the change was in the normal physiological range. CONCLUSIONS: These results suggest the possibility that the endogenous benzodiazepine system is likely to play an inhibitory role in the regulation of respiration, especially in the maintenance of upper airway patency but the system is unrelated to the chemosensitive-respiratory control.

Comparative analysis of apoptosis-inducing activity of codeine and codeinone.

BACKGROUND: There are relatively few studies about the antiproliferative effects of codeine-related compounds on human cancer cell lines, compared with those of morphine-related compounds. The authors previously found that codeinone, an oxidation metabolite of codeine, among 10 opioids, showed the highest cytotoxic activity (DNA fragmentation-inducing activity) against human promyelocytic leukemic cell lines (HL-60). This was counteracted by an antioxidant, N-acetyl-L-cysteine (NAC). These findings prompted us to perform a more detailed study of apoptosis induction after codeinone treatment. METHODS: Apoptosis was induced by treating HL-60 cells for 1-6 h with codeine or codeinone. DNA fragmentation was assessed by both agarose gel electrophoresis and fluorometric determination of the fragmented DNA after staining with diamidinophenylindole (DAPI). The appearance of apoptotic cells was monitored by microscopic observation after staining with Hoechst (H)-33342, and fluorescence activated cell sorter (FACS) after staining with Annexin. The release of cytochrome c and cytochrome oxidase from mitochondria and activation of caspase 3 were monitored by Western blot analysis. Intracellular caspase 3-like activity was confirmed by FACS, using cell permeable substrate. Mitochondrial manganese-containing superoxide dismutase (MnSOD) activity and mRNA expression were assayed by activity staining after separation on the polyacrylamide gel electrophoresis, and reverse transcriptase-polymerase chain reaction (RT-PCR), respectively. RESULTS: Codeinone induced internucleosomal DNA fragmentation and production of Annexin-positive apoptotic cells more potently than codeine in HL-60 cells. Codeinone stimulated the release of both cytochrome c and cytochrome oxidase, and cleavage of procaspase 3 without significant changes in both the activity and expression of MnSOD. CONCLUSIONS: Codeinone was found to possess both apoptosis and necrosis-inducing activity, in addition to the reported antinociceptive activity, further substantiating its antitumor potential.

[How do diazepam and flumazenil influence respiratory control by the activities of both hypoglossal and phrenic nerves in rabbits?].

BACKGROUND: Upper airway obstruction and inadequate ventilation often arise during sedation and anesthesia by benzodiazepines. To estimate the influence of benzodiazepines on the respiratory control, we studied the effect of diazepam and flumazenil on the neural activity and the respiratory response caused by a brief (60 sec) respiratory arrest (RA) observed in the hypoglossal nerve (HG) and phrenic nerve (PH) in rabbits. METHODS: Experiments were preformed on adult rabbits vagotomized, paralyzed and ventilated artificially with 50% N2O, 50% oxygen and 0.3-0.5% sevoflurane. We evaluated and compared the effects of diazepam and flumazenil on the peak amplitude (AMP-HG&PH) and the root mean square (RMS-HG&PH) of HG and PH, and respiratory cycle (Tc). RESULTS: Diazepam depressed HG activity more than PH activity with no influence on Tc. But it did not cause dose-related depression. Flumazenil 0.2 mg.kg-1 completely reversed the respiratory depressions caused by diazepam with the increased Tc. In addition to augmentation of the hypoglossal activity in inspiration, flumazenil caused a rise in its activity in pan-expiratory period in some cases. Additional administration of diazepam 6 mg.kg-1 following flumazenil depressed PH activity again, but did not affect HG activity any more. There was no significant depression in cardiovascular parameters with tested dosages of diazepam and flumazenil. RA response was characterized by raised AMPs and augmented RMSs (delta AMPs, delta RMSs) with marked prolongation in Tc (delta Tc). Diazepam depressed RA response dose dependently, but flumazenil did not seem to antagonize this depression. CONCLUSIONS: These results suggest that 1) flumazenil is not only a specific antagonist of benzodiazepines but also a potential excitatory agent of hypoglossal nerve activity, and that 2) there is some functional diversity in disposition of benzodiazepine-receptor binding GABAA-receptor responsible for neural respiratory control system.

Induction of cell death by pro-oxidant action of Moxa smoke.

Moxa smoke induced internucleosomal DNA fragmentation in human promyelocytic leukemic HL-60 cells, but not in other cell lines. The cytotoxic activity of Moxa smoke was significantly reduced by a popular antioxidant, N-acetyl-L-cysteine (NAC). Moxa smoke showed oxidation potential (measured by NO monitor) and produced carbon radical (measured by ESR spectroscopy). The addition of NAC significantly reduced both the oxidation potential and carbon radical intensity of Moxa smoke. Activity staining of polyacryamide gel electrophoresis of MnSOD revealed the possible modification of the conformation and/or activity of this enzyme at an early stage of HL-60 cell death. These data suggest that Moxa smoke induces cytotoxicity by its pro-oxidant action.

Partial purification of cytotoxic substances from moxa extract.

The major cytotoxic activity of Moxa was extracted with CH2Cl2 and partially purified by three cycles of silica gel column chromatography. The active fractions showed higher cytotoxicity against six human tumor cell lines (two oral squamous cell carcinoma, one salivary gland tumor, one melanoma, two leukemia) than three normal oral human cells (gingival fibroblast, periodontal ligament fibroblast, pulp cell). All fractions failed to protect the cells from the cytopathic effect induced by HIV infection. ESR spectroscopy showed that all fractions produced little or no radical under alkaline conditions, while showing much lower O2- scavenging activity, generated by hypoxanthine-xanthine oxidase reaction, than antioxidants and polyphenols. Active fractions induced DNA fragmentation in HL-60 cells, but failed to modify the mobility and activity of mitochondrial Mn-containing superoxide dismutase (MnSOD), in contrast to Moxa smoke. These data suggest that the active principles in the Moxa extract might be different from that in Moxa smoke, which produced carbon radical and modified MnSOD mobility and activity.