Use of microdialysis for in-vivo monitoring of hydroxyl free-radical generation in the rat

Free-radicals are reported to cause the tissue-damage associated with some toxins and diseases, yet there is no suitable method for routine in-vivo monitoring of these species. This paper introduces an in-vivo microdialysis technique in which the hydroxyl radical reacts with salicylate to generate dihydroxybenzoic acids (DHBA) which are measured by HPLC with electrochemical detection. When pargyline, a monoamine oxidase inhibitor, was infused into rat brain, the levels of DHBA increased markedly. When noradrenaline was administered to animals pre-treated with pargyline, DHBA levels increased markedly compared with the group treated with noradrenaline only. When the heart was subjected to 15-min regional ischaemia by occlusion of the left anterior descending coronary artery, levels of DHBA in heart dialysate were unchanged. Electrical stimulation of the stellate ganglion resulted in marked elevation of levels of DHBA the myocardial dialysate. Infusion of Fe2+ into rat liver resulted in increased formation of DHBA. When the intestine was rendered ischaemic for 10, 20 and 30 min, the highest DHBA level was obtained after 10-min ischaemia and the lowest after 30 min. These results confirm that free-radical production might make a major contribution at certain stages in the progression of the injury.

[Metabolic imaging of human brain tumors: H-1 chemical shift imaging and PET]

Positron Emission Tomography(PET) and Proton Chemical Shift Imaging(1H-CSI) has provided a cerebral metabolism. The glucose analog fluorine-18 fluorodeoxy-glucose(FDG) and amino acid analog 11C-L-methionine is the most commonly used PET tumor tracer. This time we compare with 1H-CSI and PET in gliomas and metastatic brain tumor with computer-assisted fusion images. We experienced some cases of the brain tumor. One case is metastatic brain tumor after radiation therapy, localized in right parietal hemisphere, with hemorrhage, and slightly accumulated Gd-DTPA in tumors. 11C-methionine PET demonstrates defects in tumors, but slight accumulated surrounding tumors. Accumulation of PET lesion is not elevated choline in CSI, but lactate is accumulated in tumors. Choline signal elevation seen in brain neoprasms, associated with increased cellular proliferation. Accumulation of PET and another accumulation of lactate in tumor are not demonstrate recurrence. Fusion image of PET and CSI is useful in understanding metabolism of brain tumor.

Anti-tumor mechanisms of 3'-ethynyluridine and 3'-ethynylcytidine as RNA synthesis inhibitors: development and characterization of 3'-ethynyluridine-resistant cells

To discover the mechanisms of anti-tumor action of 3'-ethynyluridine (EUrd) and 3'-ethynylcytidine (ECyd), we established an EUrd-resistant variant from human fibrosarcoma HT-1080 cells. The cells were cross-resistant to ECyd. Uridine/cytidine kinase activity diminished in the resistant cells. The incorporation of EUrd and ECyd into the RNA fraction in the resistant cells was less than that of the parental cells. EUrd-triphosphate inhibited RNA synthesis by human RNA polymerase II. The results led us to conclude that EUrd and ECyd are phosphorylated by uridine/cytidine kinase to 5'-triphosphates, and that their triphosphates might inhibit RNA polymerase.

Protective effect of diltiazem on myocardial ischemic injury associated with .OH generation

We examined the protective effect of diltiazem, a calcium antagonist, on myocardial ischemic injury associated with generation of hydroxyl free radicals (.OH). Salicylic acid in Ringer's solution (0.5 nmol.microliter-1.min-1) was infused directly through a microdialysis probe to detect the generation of .OH as reflected by the formation of 2,3-dihydroxybenzoic acid (DHBA) in the myocardium. Cardiac dialysate was assayed for 2,3-DHBA by a high-performance liquid chromatographic-electrochemical (HPLC-EC) procedure. The heart was subjected to myocardial ischemia for 15 min by occlusion of left anterior descending artery (LAD). The presence of .OH was indicated in the ischemic reperfused rat heart. However, when heart was reperfused, the elevation of 2,3-DHBA by 15-min ischemia was not observed in the ischemic zone following systemic administration of diltiazem (100 micrograms.min-1.kg-1), a calcium antagonist. When corresponding experiments were performed with allopurinol (10 mg.kg-1) administration of i.v. injection, the elevation of 2,3-DHBA was not observed. These results suggest that diltiazem may suppress the .OH generation from xanthine-xanthine oxidase system by ischemia-reperfusion.

Cardiac microdialysis of salicylic acid .OH generation on nonenzymatic oxidation by norepinephrine in rat heart

The effect of pargyline, a monoamine oxidase inhibitor, on the generation of hydroxyl free radicals (.OH) was investigated using cardiac microdialysis. Salicylic acid in Ringer's solution (0.5 nmol x microL(-1) x min(-1)) was infused directly through a microdialysis probe to detect the generation of .OH as reflected by the formation of dihydroxybenzoic acid (DHBA) in the myocardium of anesthetized rats. When pargyline (100 nmol x microL(-1) x min(-1)) was infused in rat heart, the level of norepinephrine (NE) gradually increased in a time-dependent manner and an increase of DHBA was also observed. When NE was administered to the pargyline pretreated animals, a marked elevation in the levels of 2,3- and 2,5-DHBA formation was obtained, as compared to the group treated with NE only, showing a positive linear correlation between NE and .OH formation trapped as 2,3-DHBA (R2 = 0.981) or 2,5-DHBA (R2 = 0.984) in the dialysate. NE clearly produced an increase in .OH formation. These results indicate that accumulation of NE in the extracellular fluid elicited by pargyline can be auto-oxidized, which in turn, leads (possibly by an indirect mechanism) to the formation of cytotoxic .OH free radicals.

Continuous isoproterenol inhalation therapy in children with severe asthmatic attack

We studied the 1-type isoproterenol inhalation therapy for patients with severe asthmatic attacks who were admitted at the Department of Allergy of National Children's Hospital from 1981 to 1991. One hour after l-type isoproterenol inhalation therapy, statistically significant effects were noted with regard to the asthmatic status. Moreover, no side effect was found amoung the subjects. From these data, 1-type isoproterenol inhalation therapy is thought to be effective for severe asthmatic attacks.

[Immunohistochemical study of thymidine phosphorylase in uterine cervical intraepithelial neoplasia]

Studies have shown that thymidine phosphorylase (TdRPase) activity in various tumors is higher than that in normal tissues. We studied the immunohistochemical localization of TdRPase in uterine cervical intraepithelial neoplasia (CIN) using monoclonal antibody against TdRPase. Sixty-nine patients were studied: CIN 1, 14; CIN 2, 15; CIN 3 (severe dysplasia), 23; CIN 3 (carcinoma in situ), 17. Immunoreactivity for TdRPase was found in 29% of CIN 1, 40% of CIN 2, 70% of CIN 3 (severe dysplasia), and 88% of CIN 3 (carcinoma in situ), showing increasing incidence with the progression of tumor grade. Furthermore, in higher grade tumor, more immunoreactive cells were found with increased intensity of immunoreaction. Both nucleus and cytoplasm of atypical cells showed immunoreactivity in most TdRPase positive cases, while either nucleus or cytoplasm was positive in a few cases. The stromal tissues were negative for the antibody except 3 cases of CIN 3 (carcinoma in situ) in which the stromal tissues adjacent to the tumor was positive. Our data suggest that immunoreactivity of TdRPase in CIN may correlate with the grade of CIN.

Acacia concinna saponins. I. Structures of prosapogenols, concinnosides A-F, isolated from the alkaline hydrolysate of the highly polar saponin fraction

A highly polar saponin mixture from pods of Acacia concinna (Leguminosae) was hydrolyzed with alkali to yield five new triterpenoidal prosapogenols named concinnosides A (6), B (3), C (7), D (4), and E (8), together with four known glycosides, acaciaside, (2), julibroside A1 (10) julibroside A3 (9), albiziasaponin C (5), and their aglycone, acacic acid lactone (1). The structures of these new prosapogenols were elucidated based on spectroscopic means. A less polar saponin fraction from the pods gave spinasteryl glucoside and its dihydro derivative.

Protective effect of carbidopa on hydroxyl radical generation in the rat striatum by dopamine

The effect of L-3,4-dihydroxyphenylalanine (L-DOPA) on the generation of hydroxyl free radicals (.OH) was investigated using striatal microdialysis technique. Salicylic acid in Ringer's solution (0.5 nmol.microliters-1.min-1) was infused directly through a microdialysis probe to detect the generation of .OH as reflected by the formation of dihydroxybenzoic acids (DHBA) in the striatum. When L-DOPA (0.1 mM; 1 microliter.min-1) was infused in the rat brain, the level of 3,4-dihydroxyphenylacetic acid (DOPAC) gradually increased in a time-dependent manner. In addition, a marked elevation of DHBA was observed. However, in the presence of carbidopa, a decarboxylase inhibitor, the elevation in DHBA formation was not observed. These results suggest that carbidopa may suppress the .OH generation by dopamine (DA).

Insulin signaling and its regulation of system A amino acid uptake in cultured rat vascular smooth muscle cells

Hyperinsulinemia has been recognized as an independent risk factor for atherosclerosis. However, its exact mechanisms are still unclear. In our previous work, we showed that 10 nmol/L insulin stimulated neither mitogen-activated protein kinase (MAP kinase) activity nor [3H]thymidine incorporation but did stimulated S6 kinase through the specific insulin receptors in cultured rat vascular smooth muscle cells (VSMCs). In this study, we observed that > or = 1 nmol/L insulin stimulated tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) and activated IRS-1-dependent phosphatidylinositol 3'-kinase (PI 3'-kinase) and p70 S6 kinase (p70S6K) but not MAP kinase (extracellular signal-regulated kinase 2) and p90 S6 kinase (p90RSK). However, 10 nmol/L insulin-like growth factor I stimulated all these pathways. Finally, 10 nmol/L insulin stimulated alpha-amino-isobutyric acid (AIB) uptake, and wortmannin (100 nmol/L) completely inhibited insulin-stimulated AIB uptake, whereas rapamycin (20 nmol/L) had no such effect. Furthermore, cycloheximide (10 micrograms/mL) completely inhibited insulin-stimulated AIB uptake, but actinomycin D (5 micrograms/mL) failed to inhibit this. Thus, we reached the following conclusions: (1) Insulin (1 nmol/L) induced phosphorylation of IRS-1 and activated the PI 3'-kinase and p70S6K pathways in VSMCs, even though 10 nmol/L insulin did not significantly stimulate MAP kinase or p90RSK. (2) Stimulation of AIB uptake by insulin was regulated at the translational level via wortmannin-sensitive pathways but not p70S6K pathways.

SHPTP2 serves adapter protein linking between Janus kinase 2 and insulin receptor substrates

To investigate the role of Janus kinase family (JAK1 and JAK2) in insulin signaling, we assessed their insulin-induced associations with other molecules in the cells overexpressing insulin receptors (HIRc and CHO-IR). After insulin stimulation, pp185 proteins (insulin receptor substrate, IRS) were co-immunoprecipitated with both kinases by alpha JAK1 and alpha JAK2 antibodies. However, JAK2 constitutively associated with pp95 protein (IR beta). Moreover, JAK2 also constitutively bound to a protein tyrosine phosphatase containing Src 2 regions (SHPTP2), but JAK1 did not. In HIRc cells expressing PTPase-negative mutant SHPTP2, no association of JAK2 with either pp185 or pp95 was detected. Thus, SHPTP2 might serve as an adapter protein linking between JAK2 and IRS. These results suggest that JAK1 and JAK2 behave differently and they may constitute a new regulatory component in insulin signaling.

[Evaluations of a specified number of inhalations and how to assess the contents in metered-dose inhalers]

Many kinds of Metered-Dose Inhalers (MDI) have been clinically available for bronchial asthma. Although manufacturers demonstrate the specified number of inhalations per canister on an attached document or on a plastic bag, the information provided are usually inadequate and inconsistent. They provide no information on the problems of the Metered-Dose Inhalers beyond the maximum specified number of actuations and the time when to exchange for a new one. We examined the technique how to evaluate the contents of MDI and their accuracy. Patients and their parents depended on inaccurate methods, such as shaking the inhalers to listen to the sound of contents, estimating the weight of the canisters and the size of emissions, and only a half of them were able to distinguish between 1/3 and 2/ 3 of remaining doses. Three Metered-Dose Inhalers with anti-inflammatory drugs and one MDI with beta-stimulant supplied consistent doses until they reached the maximum specified number. The 4 MDIs floated in the water in different ways and provided information when to replace for new ones in some MDIs.

IgE-anti-IgE-induced prostaglandin D2 release from cultured human mast cells

To elucidate the characterization of cultured human mast cells, the generation of prostaglandin D2 (PGD2) upon stimulation with IgE-anti IgE challenge was determined by using gas chromatography/mass spectrometry/selected ion monitoring (GC/MS/SIM) assay. Mononuclear cells obtained from human umbilical cord blood were cultured in the presence of Steel Factor, IL-6, and PGE2. After 8 weeks of culture, approximately 90 to 95% of cultured cells became tryptase-positive and included basophilic granules. At 12 weeks of culture, cells were harvested and incubated with 1 microgram/ml of human IgE for 1 hr and then challenged with 10 micrograms/ml of anti-IgE. The level of PGD2 release into the supernatant was measured by GC/MS/SIM with the stable isotope dilution method. Cyclooxygenase inhibitors affected the PGD2 release from the cell by IgE-anti IgE challenge incubation. Indomethacin inhibited 98% of PGD2 release. Acetylsalicylic acid (aspirin) and NS-398 (potent COX-2 inhibitor) also inhibited PGD2 release by 85 and 45% respectively.

In vivo monitoring of .OH generation on jejunal ischemic injury by dialysis technique

We applied an in vivo microdialysis technique to examine free radical generation following ischemic injury in the rat jejunum. For this purpose, we used a microdialysis probe holding system. The salicylate reacts with hydroxyl free radical (.OH) and generates 2,3-dihydroxybenzoic acid (DHBA), which can be measured electrochemically in picomole amounts by high-performance liquid chromatography (HPLC). Therefore, the former was used for trapping the .OH formation. Reperfusion of the jejunum produced progressive elevations in the levels of 2,3-DHBA achieving the maximums at 20 min, after which they decreased progressively to the baseline. These elevations were significant only after 10 min- and 20 min-ischemia. However, this change was not significant in the case of 30 min-ischemia. Ischemia-reperfusion of rat intestine caused morphological changes. These results suggest that .OH production is significantly reduced after 30 min-ischemia providing thus the possibility for more severe intestinal damage. In conclusion our dialysis probe can be useful for the measurement of .OH generation following ischemia-reperfusion injury.

Eosinophil chemotactic activity in Leishmania amazonensis promastigotes

Tissue eosinophilia was observed in the subcutaneous tissue of mice shortly after their inoculation not only with living but also with lysed promastigotes of Leishmania amazonensis. Intraperitoneal inoculation of lysed promastigotes from five different Leishmania species (L. donovani, L. chagasi, L. tropica, L. amazonensis, and L. braziliensis) induced eosinophil accumulation in the mouse peritoneum. This eosinophil infiltration was also detected in C5-deficient AKR mice, indicating complement independent eosinophil chemotaxis by the parasite. The induced eosinophils were hypodense, suggesting activation of the cells. Finally, we demonstrated in vitro eosinophil chemotactic activity in the promastigote lysates using purified eosinophils and blind well chambers. These results suggest the presence of an eosinophil chemotactic factor in Leishmania, a protozoan parasite.

[Expression of Fas/Fas ligand and proto-oncogenes in rheumatoid synovial tissues]

Expression of Fas antigen and Fas ligand (-L) were observed in synovial tissue from rheumatoid arthritis (RA) patients, whereas in only a few cells expressed these molecule osteoarthritis synovial tissue. Fas-L was expressed on CD45RO, CD4, CD8 or CD56 positive cells in RA synovial tissue. Moreover, 10 to 30% of synovial cells expressing Fas antigen were observed to be identical with apoptotic synovial cells and Fas expression was closely related to c-fos and c-myc. These findings suggest that activated T cells and natural killer cells infiltrating into the RA synovium may play an important role in the induction of apoptosis of RA synovial cells through Fas/Fas-L interactions.

Cardiac microdialysis of salicylic acid to detect hydroxyl radical generation associated with sympathetic nerve stimulation

We examined the relationship between norepinephrine (NE) and hydroxyl free radical (OH) generation on cardiac nerve stimulation. Salicylic acid in Ringer's solution (0.5 nmol microliter-1 min-1) was infused directly through a microdialysis probe to detect the generation of hydroxyl radicals (OH) as reflected by the formation of dihydroxybenzoic acid (DHBA) in the myocardium of anesthetized rats. Sympathetic nerve stimulation increased the release of NE and the formation of DHBA. A positive linear correlation between the release of NE and the formation of 2,3-DHBA (R2 = 0.982) or 2,5-DHBA (R2 = 0.976) was observed. These data indicate that the sustained elevation of NE in the extracellular fluid can be auto-oxidized, which in turn leads (possibly by an indirect mechanism) to the formation of cytotoxic OH free radicals.

Role of adenosine in blood flow in the rat intestine

We examined the relation between adenosine production and increased blood flow. For this purpose, we used a sensor holding system with a laser Doppler blood flowmeter. The elevation of blood flow was observed by administration of adenosine. Therefore, when AMP was administered to the rats, the elevation of blood flow rate was observed. These results suggest that AMP is rapidly transported to the adenosine active site by ecto-5'-nucleotidase.

Monoamine oxidase released into plasma treated with the hepatotoxin allyl formate

Monoamine oxidase (MAO) released from the rat liver into plasma and the activity levels of lipid peroxide (LPO) and superoxide dismutase (SOD) in liver tissue were investigated after pretreatment of rats with the perilobular hepatotoxin allyl formate (AF). When 3H-pargyline was given to AF-pretreated rats, the levels of 3H-pargyline labelled MAO in rat plasma were increased to 38% (p < 0.01 vs control), but the radioactivity was decreased to 35% (p < 0.05 vs control). The molecular weight of MAO subunits in plasma was similar to that of MAO subunits in liver (about 60,000) as determined by SDS electrophoresis. Liver tissue LPO levels in these rats were increased, whereas SOD activity was decreased. These results suggest that MAO in liver mitochondria was released into plasma as a consequence of membrane disorder.

Effect of iron (II) on the generation of hydroxyl free radicals in rat myocardium

We examined the effect of iron (II) on the generation of hydroxyl radicals (.OH) in the extracellular fluid of rat myocardium. Salicylic acid in Ringer's solution (0.5 nmole x microliter(-1) x min(-1)) was directly infused through a microdialysis probe to detect the generation of OH as reflected by the formation of dihydroxybenzoic acid (DHBA) in the myocardium. Iron clearly produced a dose-dependent increase in .OH formation. A positive linear correlation between iron (II) and the formation of 2,3-DHBA (R2 = 0.970) or 2.5-DHBA (R2 = 0.983) was observed. However, when desferrioxamine (DES) was infused through a dialysis probe, a marked increase in DHBA formation was obtained. The present results suggest that iron (III) may reduce .OH formation by the Fenton reaction.

Major Dermatophagoides mite allergen, Der 1, in soft toys

BACKGROUND

Allergen avoidance is recommended when treating atopic asthma.

OBJECTIVES

Soft toys are often kept in close proximity to children and may serve as a source of exposure. Due to the potential danger from the mite allergen content of these toys, Der 1 from toys was measured.

METHODS

We quantified the level of Der 1 (Der p 1 + Der f 1) in both 30 new and 174 old soft toys (weight 216 +/- 2.5 g, height 26.5 +/- 3.4 cm), as well as in washed and in vacuumed soft toys. Dust was collected using an electric vacuum cleaner. Der 1 was measured by monoclonal antibody-based enzyme-linked immunosorbent assay (MoAb-ELISA).

RESULTS

In brand new toys Der 1 was 0.1 microgram/g of dust, and in toys used for 1 year, 9.0; 2 year, 22.2; 3 year, 18.9; and more than 4 year, 22.7 micrograms/g of dust. Der 1 in new toys was measured every 4 months for 1 year. Der 1 rapidly increased 10- to 20-fold in the first 4 months, but there was no clear seasonal change. In toys washed using a chemical detergent or cleaned using a vacuum cleaner, there was a stastistically significant (P < 0.001) decrease in Der 1 in the washed group, but not in the vacuumed group.

CONCLUSION

These results confirm that mite allergens accumulate rapidly in toys to form a potentially important source of allergens and that washing toys with a chemical detergent is effective in the reduction of allergens.