Effects of sevoflurane and isoflurane on renal function and on possible markers of nephrotoxicity

BACKGROUND

Low-flow sevoflurane anesthesia is associated with increasing circuit concentrations of compound A, which is nephrotoxic in rats, but the effect of compound A and low-flow sevoflurane anesthesia on renal function in humans is unclear. The authors compared the effects of high- and low-flow sevoflurane and isoflurane anesthesia on renal function and on several possible markers of nephrotoxicity in humans.

METHODS

Forty-two patients without preexisting renal disease underwent either low-flow isoflurane (1 l/min, n = 14), low-flow sevoflurane (1 l/min, n 14), or high-flow sevoflurane (6 l/min, n = 14) anesthesia for body-surface-area surgery scheduled to last at least 4 h. Twenty-four-hour urinary excretion of N-acetyl-beta-glucosaminidase (NAG), beta2-microglobulin, protein, glucose, blood urea nitrogen (BUN), and serum creatinine concentrations were measured before and after anesthesia.

RESULTS

There were no differences in blood urea nitrogen, creatinine, and creatinine clearance among the three groups after anesthesia. Increased urinary N-acetyl-beta-glucosaminidase excretions were seen in the low-flow and high-flow sevoflurane groups, but not in the low-flow isoflurane group (P < 0.01). Ten patients in the low-flow sevoflurane group had 24-h urinary excretion of protein that exceeded the normal ranges after anesthesia, but only one patient in the isoflurane and none in the high-flow sevoflurane groups had this.

CONCLUSIONS

Low-flow sevoflurane anesthesia was associated with mild and transient proteinuria. However, the observed proteinuria was not associated with any changes in blood urea nitrogen, creatinine, and creatinine clearance in these patients with no preexisting renal disease.

Actions of the novel oral antidiabetic agent HQL-975 in insulin-resistant non-insulin-dependent diabetes mellitus model animals

The hypoglycemic effects of a novel oral antidiabetic agent HQL-975, were studied in normal rats, streptozotocin-induced diabetic (STZD) rats and genetically insulin-resistant non-insulin-dependent diabetes mellitus (NIDDM) model animals, KK-Ay mice and Zucker diabetic fatty (ZDF) rats. After the dietary administration of HQL-975 to KK-Ay mice, significant decreases in plasma glucose, insulin, triglyceride and non-esterified fatty acid levels were observed. The effective dosage of HQL-975 to decrease the plasma glucose level by 30% was 3.1 mg/kg per day. However, the plasma glucose level was not altered after the administration of HQL-975 in normal and STZD rats. The results suggest that HQL-975 is more effective against the abnormalities of glucose and lipid metabolism of insulin-resistant model animals than in that of normal and insulin-deficient diabetic animals. It is reported that ZDF rats indicate a severely diabetic state as a result of insulin resistance and further the presence of beta-cell insulin secretory defects. Here, HQL-975 (1-30 mg/kg per day for 7 days) was administered to ZDF rats; slight decreases in the plasma glucose (18%) and lipids (41%) levels were observed in the rats given 30 mg/kg. To clarify the action mechanism of HQL-975, we studied the effects of HQL-975 administration on the insulin action of target tissues in KK-Ay mice. After the dietary administration of HQL-975 (0.001, 0.003, 0.010% for 7 days) to KK-Ay mice, hepatic glycolytic and gluconeogenic key enzyme activities were measured. The glucose 6-phosphatase activity was decreased (20-40%) as compared with control. The results suggest that HQL-975 enhances the insulin action in hepatic enzyme regulation. To investigate the actions of HQL-975 in peripheral tissues such as muscle and adipose, an in vivo glucose uptake study using 3H-2-deoxyglucose was performed in KK-Ay mice treated with HQL-975 (0.010% for 7 days). The 2-deoxyglucose uptake of the basal state was not altered, but the insulin-stimulated 2-deoxyglucose uptake in muscle (41-191%) and adipose (46-88%) tissues was increased by the HQL-975 treatment as compared with control. These results suggest that HQL-975 also enhances the insulin action of peripheral tissues. Based on these findings, HQL-975 is expected to be useful for treatment of insulin-resistant patients with NIDDM.

A cell surface antigen that cross-reacts with My4, a monoclonal antibody to CD14, is expressed on human monoblastic cell line U937, B-lymphoma cells, and polymorphonuclear leukocytes

The CD14 antigen was originally identified on monocytes as a differentiation marker and usually detected by a panel of monoclonal antibodies, including My4 and LeuM3. Recent studies have shown that CD14 antigen is expressed on Langerhans cells, a subject of normal B-lymphocytes, neutrophils, and subtypes of B-cell non-Hodgkin's lymphomas. These antigens, however, react with My4, but not with LeuM3, and the reason for this has not been elucidated. In this study, we found that similar My4+/LeuM3- epitopes are expressed on the human monoblastic cell line, U937. Northern blotting demonstrated that the U937 cells express neither 1.4 kb CD14 transcripts nor possible alternative spliced forms of CD14 transcripts. The molecule was resistant to phosphatidylinositol specific phospholipase C, which effectively hydrolyzes glycosyl-phosphatidylinositol anchored protein, decay accelerating factor, on the same cells. Lipopolysaccharide, which down-regulates the expression of CD14 on monocytes, did not alter the expression of the molecule. We concluded that the My4+/LeuM3- molecule on U937 cells is not CD14 antigen but another surface protein. A similar molecule was also detected on B-lymphoma cells from a patient with non-Hodgkin's lymphoma and on polymorphonuclear leukocytes from healthy donors.

Functional and morphological features of skeletal muscle from mutant mice lacking both type 1 and type 3 ryanodine receptors

1. We generated mice with targeted disruptions in the genes for both ryanodine receptor type 1 (RyR-1) and type 3 (RyR-3) to study the functional roles of RyR subtypes in skeletal muscle. 2. In permeabilized myocytes lacking both the RyRs, the Ca(2+)-induced Ca2+ release (CICR) mechanism was completely lost, and caffeine failed to induce Ca2+ release. 3. Replacement of potassium methanesulphonate in an experimental intracellular solution with choline chloride resulted in Ca2+ release in the wild-type muscle but not in the mutant muscle lacking RyR-1. 4. The double-mutant mice exhibited more severe muscular degeneration than RyR-1-deficient mice with formation of large vacuoles and swollen mitochondria while structural coupling between T-tubules and the sarcoplasmic reticulum was retained. 5. These results demonstrate that CICR is mediated solely by RyR-1 and RyR-3 in skeletal muscle cells, and suggest that RyR-1 is involved in Cl(-)-induced Ca2+ release. The results also suggest the presence of molecular components other than RyRs responsible for the triad formation. RyR-3 may have a role in the normal morphogenesis of skeletal muscle cells, although functionally it can be replaced by RyR-1.

Clostridial population and the intestinal lesions in chickens infected with Clostridium perfringens and Eimeria necatrix

Chickens infected with Clostridium perfringens and Eimeria necatrix were examined bacteriologically and pathologically. When chickens were inoculated with 1.0 x 10(8) C. perfringens and/or 2 x 10(4) E. necatrix sporulated oocysts, populations of C. perfringens in the intestinal contents were examined on 3, 5 and 7 days after E. necatrix inoculation. In both groups infected with E. necatrix, the mean clostridial counts were significantly higher than those of uninfected controls. The concurrent infection had no enhancing effects on increasing the clostridial population more than E. necatrix-alone. Mortality of 4-day-old chickens inoculated on 5 consecutive days with C.perfringens after receiving E. necatrix was higher than those of chickens inoculated with the both organisms. However, intestinal lesions of the concurrently infected group were not different from E. necatrix-alone-infected group on 5 and 7 days after the coccidial infection. When chickens received a large dose (1.5 x 10(9)) of C. perfringens after the inoculation with E. necatrix, edema in the duodenum through jejunum were observed early after the bacterial broth inoculation. These results suggest that the concurrent infection with E. necatrix and C. perfringens increases clostridial population in the intestine of the chickens and has synergic effects on mortality and edema in the upper intestine.

Effects of androgen receptor polyglutamine tract expansion on proliferation of NG108-15 cells

Expansion of the polyglutamine tracts in the androgen receptor (AR) has been recognized as a cause of X-linked spinal and bulbar muscular atrophy (SBMA). In the present study, NG108-15 cells were stably transfected with expression vectors coding for either the wild type (WT) AR gene (CAG repeat number = 22) or a mutated (MT) AR gene (CAG repeat number = 52). Cells proliferation and cell cycle parameters were evaluated for NG108-15-WT and NG108-15-MT cells in the presence or absence of androgen. NG108-15-WT cells demonstrated an androgen-dependent increase in cell number, while NG108-15-MT cells did not. Our results demonstrate that expansion of polyglutamine tracts in the AR may affect the proliferation and differentiation of nerve cells.

Effects of ethyl alpha-D-glucoside on skin barrier disruption

Daily treatments of skin in hairless mice with concentrates of rice wine, Japanese traditional alcohol, lowered transepidermal water loss levels compared to the controls on the 3rd day after ultraviolet B (UVB) irradiation. These findings indicate that the concentrates of rice wine suppress the murine skin barrier disruption caused by UVB. Ethyl alpha-D-glucoside (alpha-ethylglucoside), one of the peculiar components in rice wine, showed the same effect, whereas beta-ethylglucoside had no effect. In order to clarify the functions of alpha-ethylglucoside on murine skin, we examined the effects of this compound on the expression of some phenotypes in human keratinocytes in vitro. As a result, alpha-ethylglucoside as well as beta-ethylglucoside enhanced cell proliferation weakly, and the formation of cornified envelopes and differentiated type keratin (K1) in keratinocytes was accelerated by alpha-ethylglucoside but not by beta-ethylglucoside. From the results, we conclude that alpha-ethylglucoside enhanced the differentiation of keratinocytes, which might be related to reduced barrier disruption by UVB.

Native structure and arrangement of inositol-1,4,5-trisphosphate receptor molecules in bovine cerebellar Purkinje cells as studied by quick-freeze deep-etch electron microscopy

We used quick-freeze deep-etch replica electron microscopy to visualize the native structure of inositol-1,4,5-trisphosphate receptor (IP3R) in the cell. In the dendrites of Purkinje neurons of bovine cerebellum there were many vesicular organelles whose surfaces were covered with a two-dimensional crystalline array of molecules. Detailed examination of the cytoplasmic true surface of such vesicles in replica revealed that the structural unit, identified as IP3R by immunocytochemistry and subsequent Fourier analysis, is a square-shaped assembly and is aligned so that the side of the square is inclined by approximately 20 degrees from the row-line of the lattice. Comparison with the ryanodine receptor (RyaR), another intracellular Ca2+ channel on the endoplasmic reticulum, suggested that IP3R, unlike RyaR, has a very compact structure, potentially reflecting the crucial difference in the function of the cytoplasmic portion of the molecule.

Generation and characterization of mutant mice lacking ryanodine receptor type 3

The ryanodine receptor type 3 (RyR-3) functions as a Ca2+-induced Ca2+ release (CICR) channel and is distributed in a wide variety of cell types including skeletal muscle and smooth muscle cells, neurons, and certain non-excitable cells. However, the physiological roles of RyR-3 are totally unclear. To gain an insight into the function of RyR-3 in vivo, we have generated mice lacking RyR-3 by means of the gene targeting technique. The mutant mice thus obtained showed apparently normal growth and reproduction. Although Ca2+-induced Ca2+ release from intracellular Ca2+ stores of the mutant skeletal muscle differed in Ca2+ sensitivity from that of wild-type muscle, excitation-contraction coupling of the mutant muscle seemed to be normal. Moreover, we could not find any significant disturbance in the smooth muscle and lymphocytes from the mutant mice. On the other hand, the mutant mice showed increased locomotor activity, which was about 2-fold greater than that of the control mice. These results indicate that the loss of RyR-3 causes no gross abnormalities and suggest that the lack of RyR-3-mediated Ca2+ signaling results in abnormalities of certain neurons in the central nervous system.

Effect of calmodulin antagonists on calmodulin-induced biphasic modulation of Ca(2+)-induced Ca2+ release

1. Calmodulin (CaM) has a biphasic effect on Ca(2+)-induced Ca2+ release (CICR) from the sarcoplasmic reticulum (SR): potentiation and inhibition at low (pCa > 6.0) and high (pCa 5) Ca2+ concentrations, respectively. To characterize the mode of action of CaM, we studied the effect of CaM antagonists on the CICR in skinned muscle fibres of the rabbit. Ca2+ release was measured by microfluorometry with Fura-2. 2. A CaM antagonist, trifluoperazine (TFP), potentiated the CICR in a dose-dependent manner (10-300 microM) at pCa 6, where a simple reversal of the CaM effect would be inhibition of the CICR. Furthermore, 100 microM TFP sensitized the CICR to Ca2+. A similar effect was produced by other CaM antagonists that were tested: chlorpromazine, W-7, mastoparan, and peptide fragment of CaM-binding residues of CaM-dependent protein kinase II. 3. The biphasic effect of CaM on the CICR was observed even in the presence of high concentrations of CaM antagonists or CaM-bindings peptides. 4. From these results we suggest that CaM has a unique mode of action on the CICR which is quite different from the effect of CaM on known enzymes.

Uncoupling mechanism of glycoside antibiotic aculeximycin in isolated rat-liver mitochondria

Effects of basic glycoside antibiotic aculeximycin (ACM) on the oxidative phosphorylation of rat-liver mitochondria were examined. ACM was shown to be a potent uncoupler of the oxidative phosphorylation. To cause the same extent of respiration release, higher concentration of ACM was required in phosphate (Pi)-free medium than in Pi medium. During the uncoupling caused by ACM in Pi medium, large amplitude swelling and oxidation of intramitochondrial NAD(P)H occurred, indicating that ACM remarkably enhances permeability of the inner mitochondrial membrane. The Pi uptake via Pi/H+ symporter was shown to play an important, but not essential, role in the uncoupling by ACM, indicating the increase in membrane permeability is mostly due to acceleration of Pi/H+ influx through Pi/H+ symporter activated by ACM. ACM is the first naturally occurring antibiotic, to our knowledge, which activates Pi/H+ symporter. However, since the inhibition of Pi/H+ symporter by N-ethylmaleimide did not completely abolish the uncoupling activity of ACM, and ACM induced the uncoupling even in Pi-free medium, an increase in the membrane permeability for other ions, such as Na+ and K+, due to a different action mechanism has also to be considered. On the other hand, positively charged amine local anesthetics, like dibucaine, prevented the uncoupling activity by ACM in both Pi and Pi-free medium. The uncoupling activity of N-diacetylated ACM lacking free amino groups was ca. 1/120th that of ACM, indicating that positively charged amino groups are important for the uncoupling activity. It is suggested that some specific interactions between positively charged amino groups of ACM and the binding site, which is probably negatively charged, are triggers that affect the permeability of the inner mitochondrial membrane. Amine local anesthetics may mask the negative charge of the binding site, thereby interfering with ACM binding.

Varied effects of thoracic irradiation on peripheral lymphocyte subsets in lung cancer patients

To investigate the influence of thoracic irradiation on immunological competence in patients with lung cancer, we examined the changes in peripheral blood lymphocyte subsets in 15 patients before and after radiation therapy by two-color flow cytometry techniques. After radiation therapy, the percentage and the absolute number of CD4+CD45RA+ cells (naive T cells) and CD56+ and/or CD16+ cells (NK cells) decreased. The percentage of CD4+human leukocyte antigen-DR(HLA-DR)+ cells (activated CD4T cells) and CD8+HLA-DR+ cells (activated CD8T cells) increased, although the absolute number did not change significantly. Naive T cells may be more selectively damaged than memory T cells by thoracic irradiation, through their recirculation behavior. The reduction of natural killer (NK) cells is disadvantageous for anti-tumor immunity. The percentage of HLA-DR positive T lymphocytes was significantly increased, and thus the possibility of HLA-DR enhancement by irradiation cannot be excluded. Therefore, thoracic irradiation has numerous varied effects on the immunological system of lung cancer patients.

Enhancing effect of calmodulin on Ca(2+)-induced Ca2+ release in the sarcoplasmic reticulum of rabbit skeletal muscle fibres

1. We analysed the effect of calmodulin on Ca(2+)-induced Ca2+ release (CICR) in the sarcoplasmic reticulum (SR) using chemically skinned fibres of rabbit psoas muscle. Ca2+ release was measured using fura-2 microfluorometry. 2. In saponin-skinned fibres, calmodulin potentiated Ca2+ release at low Ca2+ concentrations (< 3 microM), while it showed an inhibitory effect at high Ca2+ concentrations (3-30 microM). 3. Co-application of ryanodine and calmodulin at 0.3 microM Ca2+, but not ryanodine alone, induced a decline in the Ca2+ uptake capacity of the SR, an effect expected from the open-lock of active CICR channels by ryanodine. Thus, potentiation of Ca2+ release by calmodulin at low Ca2+ concentrations can be regarded as a result of the activation of the ryanodine receptor. 4. Greater concentrations of calmodulin were required for potentiation of CICR at low Ca2+ concentrations (1 microM) than for inhibition at high Ca2+ concentrations (10 microM). 5. In beta-escin-permeabilized fibres in which intrinsic calmodulin was retained, the rates of CICR were similar to those measured in the presence of 1 microM calmodulin in saponin-permeabilized fibres. 6. These results suggest that calmodulin plays an important role in the regulation of CICR channels in intact skeletal muscle fibres.

[Evaluation of the polymerase chain reaction for diagnosis of tuberculous meningitis]

Since Shankar et al used polymerase chain reaction (PCR) for detection of Mycobacterium tuberculosis (M. tuberculosis) in cerebrospinal fluid (CSF), there have been numerous reports on PCR assay for diagnosis of tuberculosis meningitis (TBM). The PCR assay have been recognized to be a rapid method for diagnosis of TBM, however there are problems of PCR sensitivity when dealing with CSF samples containing small amount of M. tuberculosis DNA. Comparing direct PCR with nested PCR, we studied on the evaluation of PCR for diagnosis of TBM. In present study the nested PCR were positive in all CSF specimens from 4 patients with TBM, but we could not detect M. tuberculosis DNA by only the direct PCR. Because nested PCR amplification improved the sensitivity and specificity, the nested PCR assay will be necessary for rapid diagnosis of TBM on the clinical laboratory.

Structural elucidation of aculeximycin. III. Planar structure of aculeximycin, belonging to a new class of macrolide antibiotics

The planar structure of aculeximycin (1) produced by Streptosporangium albidum has been determined by spectral methods and chemical degradations such as 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU)-methanol reaction, ozonolysis, and periodative oxidation. The antibiotic consists of a 30-membered polyhydroxy lactone ring, an alpha, beta-unsaturated ester group, an intramolecular hemiketal, an oligosaccharide (aculexitriose), a neutral sugar and an amino sugar. The structure of aculeximycin is closely related to those of sporaviridins produced by Streptosporangium viridogriseum. We consider that aculeximycin and sporaviridins belong to a new class of macrolide antibiotics, which is different from the polyol macrolides produced by Streptomyces.

Structural elucidation of aculeximycin. IV. Absolute structure of aculeximycin, belonging to a new class of macrolide antibiotics

Aculeximycin (1) produced by Streptosporangium albidum possesses a 30-membered polyhydroxy macrocyclic lactone and five sugars including aculexitriose. We have described the determination of the planar structure of N-diacetylated aculeximycin (2) using degradation products, which were obtained by DBU-methanol treatment, ozonolysis and periodative oxidation. In order to determine the relative and absolute configurations of aculeximycin, first, the relative and absolute configurations of the degradation products 10, 11, 12 and 13 were determined. Rychnovsky's method was very useful to determine the relative configurations of these degradation products, and CD exciton chirality and the modified Mosher's methods were applied to determine their absolute configurations. From these results, fourteen out of the twenty asymmetric centers in aculeximycin were determined to be 5S, 17R, 20S, 21R, 23R, 24R, 29S, 30R, 31S, 34R, 35S, 36S and 37R. The absolute configurations at C-14 and C-15 on the hemiketal ring were confirmed using 12 obtained by the partial glycol bond cleavage of 9. Absolute configurations of the remaining asymmetric centers were determined by spectral analysis of 15 and NOE experiment on 1. From these results, the absolute configuration of 1 was determined to be 5S, 7R, 10S, 11R, 14R, 15S, 17R, 19R, 20S, 21R, 23R, 24R, 25S, 29S, 30R, 31S, 34R, 35S, 36S and 37R.

Ca(2+)-induced Ca2+ release in myocytes from dyspedic mice lacking the type-1 ryanodine receptor

While subtypes 1 and 2 of the ryanodine receptor (RyR) function as intracellular Ca2+ release channels, little is known about the function of the third subtype (RyR-3), first identified in brain. Myocytes from mice homozygous for a targeted mutation in the RyR-1 gene (dyspedic mice) can now be used for a study on the function of RyR-3, which is predominantly expressed in these cells according to our reverse transcription-polymerase chain reaction analysis. We here demonstrate in these myocytes caffeine-, ryanodine- and adenine nucleotide-sensitive Ca(2+)-induced Ca2+ release with approximately 10 times lower sensitivity to Ca2+ than that of RyR-1. Although RyR-3 does not mediate excitation-contraction coupling of the skeletal muscle type, we propose that RyR-3 may induce intracellular Ca2+ release in response to a Ca2+ rise with a high threshold.

[Quantitative flowcytometric analysis of B cell surface antigens in patients with autoimmune diseases]

In 47 cases of autoimmune diseases (25 SLE, 9 MCTD, 6 PSS, 7 RA), two B cell surface antigens, CD19 and CD20 were quantitatively measured with a flowcytometer. When compared with the results of healthy controls, CD19 antigens were observed to be ca. 10% decreased in SLE and ca. 20% increased in RA. CD20 antigens were observed to be ca. 25% increased in SLE and no changes in RA. No significant increase nor decrease was observed with MCTD and PSS patients. In SLE patients, the amount of CD19 antigen expression was positively related to serum C3 levels, and that of CD20 antigen was negatively related to it. It is not obvious in what mechanism the expression of these antigens are regulated, however, from the point that the expression relates to the amount of serum C3 level, the quantitative measurement of CD19 and CD20 antigens is possibly be a good marker to detect the state of autoimmune disease such as SLE.

Effective inhibition of hydroxyl radicals by hydroxylated biphenyl compounds

In aqueous media, approximate rate constants for the reactions between hydroxyl radicals (.OH) and biphenyl compounds such as dehydrodieugenol, magnolol, honokiol, dehydrodidihydroeugenol, dehydrodivanillyl alcohol, and dehydrodicreosol were estimated by competition reactions for .OH between these biphenyls and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). By measuring the decrease in the height of the EPR signals of the .OH spin adduct, rate constants in the order of 10(9) to 10(10) M were measured.

Synthesis and pharmacological evaluation of (nitrooxy)alkyl apovincaminates

A series of (nitrooxy)alkyl apovincaminates has been synthesized and evaluated for their effects on vertebral and femoral blood flow. These derivatives were prepared from apovincaminic acid (4). In cerebral circulation, compound 5 (0.03-1.0 mg/kg iv) caused a dose-dependent increase in cerebral blood flow (CerBF) without affecting the blood pressure. It was more potent than vinpocetine (2). The structures of 2 and 5, determined by X-ray crystallography, showed differences in the electrostatic potential image and in the conformation of the ethyl group at the 16-position.

[Ring eosinophils in patients with lowered eosinophil peroxidase activity]

Leucocyte cytograms were obtained by using a Technicon H6000 (Technicon Instrument Corporation, Tarrytown, NY, USA) in conjunction with an automated flow-cytochemical analyser by which leucocytes can be differentiated by cytochemical (peroxidase activity) and optical (cell size) methods. By analysis of cytograms obtained in this way, we found twelve cases of lowered eosinophil peroxidase activity among approximately 600,000 blood samples-days between 1984 and 1989. Ring eosinophils were observed on the peripheral blood smears in 2 out of 12 cases. The first case was a 41-year-old female confined to hospital with Hashimoto's disease, and the other a 54-year-old female hospitalized for trauma. In both cases, the percentage of eosinophils was normal, although some had ring-shaped nuclei with a large central nuclear hole and a nuclear ring formed with a thin nuclear chromatin bridge. Ring eosinophils previously have been described in patients with hematological malignancy, hypereosinophilic syndrome or severe alcoholism. Recently we observed ring eosinophils in a healthy individual for the first time. Although ring eosinophils may not have specific diagnostic significance, these cases are reported because they displayed a rare phenomenon.

Essential oil phenyl propanoids. Useful as .OH scavengers?

In order to search for radical scavengers which could be used as raw materials for cosmetics, phenyl propanoids (eugenol, isoeugenol, dehydrodieugenol, dehydrodieugenol B and coniferyl aldehyde) were examined for their hydroxyl radical (.OH) scavenging ability. A Fenton system was used to produce .OH. In order to see scavenging by these phenyl propanoids, competition reactions between a spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), and these phenyl propanoids for .OH were studied. The relative yield of the spin adduct of .OH (DMPO-OH) was measured by electron spin resonance spectroscopy. The approximate rate constants of the reactions between these phenyl propanoids and .OH estimated by measuring the reduced height of the ESR signals of DMPO-OH were found to be at least in the order of 10(9) M-1 s-1 (diffusion-controlled). Also, using the TBA tests, the reactions between .OH and several compounds reactive with .OH were investigated in the presence of the phenyl propanoids and it was found that the phenyl propanoids compete with such reactive compounds for .OH. These results indicate that these phenyl propanoids can be used as antioxidants for skin damage perhaps caused by .OH generated by UV-light.