Superoxide anion (O2-) production stimulated by concanavalin A (Con A) in guinea pig polymorphonuclear leukocytes (PMNL) was suppressed by addition of methyl-alpha-mannoside, a Con A inhibitor, and resumed upon readdition of Con A. The reversible change in the O2- production was assumed to reflect the change in NADPH oxidase activity measured for the 30,000 X g particulate fraction. The stimulation by Con A of the phosphorylation of 46K protein(s), as observed previously with several membrane-perturbing agents in parallel with an activation of NADPH oxidase in intact guinea pig PMNL (Okamura, N., et al. (1984) Arch. Biochem. Biophys. 228, 270-277), was also suppressed by methyl-alpha-mannoside and resumed upon readdition of Con A. Similar parallelism between the phosphorylation and NADPH oxidase activity was also observed in the case of stimulation by N-formyl-methionyl-leucyl-phenylalanine (FMLP) and phorbol 12-myristate 13-acetate (PMA), though both processes were reversible after the stimulation by FMLP but not reversible after that by PMA. Thus, such a parallelism observed in both intact PMNL and 30,000 X g particulate fraction indicates possible involvement of the protein phosphorylation in the regulation of the production of active oxygen metabolites in PMNL.

Animals↗

PubMed1987

Inhibition of superoxide anion production in guinea pig polymorphonuclear leukocytes by a seleno-organic compound, ebselen.

Production of superoxide anion (O2-) induced by tetradecanoyl phorbol acetate (TPA) in intact guinea pig polymorphonuclear leukocytes (PMNL) was markedly inhibited by a seleno-organic compound, 2-phenyl-1,2-benzisoselenazol-3(2H)-one (Ebselen), with glutathione peroxidase-like activity. The compound almost completely inhibited O2- production by a particulate fraction prepared from TPA-treated PMNL at a concentration as low as 250 nM.

Animals↗

PubMed1987

Effect of ONO-3144, a free radical scavenger, on reoxygenation injury in anoxic myocardium.

Thus, ONO-3144 treatment affords great protection against reoxygenation injury in the anoxic myocardium through the scavenging mechanism that includes .OH or closely related species of free radicals and also may inhibit thromboxane synthetase in the anoxic myocardium. We would hypothesize that free radical formation generated through the conversion of PGG2 to PGH2 should play an important role in the reoxygenation injury of the anoxic myocardium.

Adenosine Triphosphate↗

PubMed1987

[Clinical effect of cefuzonam and its distribution into tissues in the field of obstetrics and gynecology].

The distribution of the new cephem antibiotic, cefuzonam (CZON) into adnexa uteri and uterine tissues, and clinical efficacy on patients with obstetric and gynecologic infections were studied. The results obtained are summarized as follows. 1. Concentrations of CZON in arterial and venous blood, oviduct, ovary, endometrium, myometrium, cervix uteri and portio vaginalis tissues were measured. The results demonstrated good transfer of the drug into various internal genital organs. 2. In clinical studies, CZON was given to 5 cases with various infections such as pyometra, acute vulvitis, pelvic peritonitis, pyelonephritis and puerperal intrauterine infection. Clinical efficacies were evaluated as excellent in 2 cases, and good in 3 cases. The efficacy rate was 100%. No side effects were observed in any cases. In laboratory tests, transient elevations of GOT, GPT and gamma-GTP were observed in 1 case. Therefore, it is concluded that CZON is a useful drug for various types of infections in the field of obstetrics and gynecology.

Adult↗

PubMed1986

Involvement of protein kinase C in the phosphorylation of 46 kDa proteins which are phosphorylated in parallel with activation of NADPH oxidase in intact guinea-pig polymorphonuclear leukocytes.

Two proteins (Mr 46,000, pI 6.4 and 7.0), the phosphorylation of which was increased by any of the membrane-perturbing agents in parallel with activation of NADPH oxidase in intact guinea-pig polymorphonuclear leukocytes in our previous study (Okamura, N., Ohashi, S., Nagahisa, N. and Ishibashi, S. (1984) Arch. Biochem. Biophys. 228, 270-277), were also phosphorylated in a cell-free system prepared from the leukocytes. The in vitro phosphorylation of these two proteins was stimulated by the addition of phosphatidylserine in the presence of higher concentrations of Ca2+ (300-500 microM). The phosphorylation was further increased when protein kinase C partially purified from guinea-pig brain was added to the system. At a low concentration of Ca2+ (about 10 microM), stimulation of the phosphorylation was not attained by phosphatidylserine alone but required the addition of diacylglycerol or phorbol myristate acetate. On the other hand, the increase in the phosphorylation was inhibited by H-7, an inhibitor for protein kinase C. These results indicate that protein kinase C is involved in the phosphorylation of the two proteins, which may be related to the superoxide anion production stimulated by various membrane-perturbing agents.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1986

A change in the lipid fluidity of the porcine intestinal brush-border membranes by lipid peroxidation. Studies using pyrene and fluorescent stearic acid derivatives.

The effect of lipid peroxidation on the lipid fluidity of porcine intestinal brush-border membranes was examined by measuring the rotational mobility and the accessibility to fluorescence quenchers (CH3COOT1, CuSO4 and KI) of pyrene or n-(9-anthroyloxy)stearic acid (n = 2 or 12) in the membranes. The harmonic mean of the rotational relaxation times of pyrene increased and the rate constants, kq, of the quenching reaction of pyrene and 2-(9-anthroyloxy)stearic acid incorporated in the membrane lipids decreased upon lipid peroxidation, indicating reduction of the lipid fluidity of the membranes by lipid peroxidation. In addition, the kq value of the reaction of 2-(9-anthroyloxy)stearic acid in the membranes with Cu2+ decreased in proportion to the amount of the products of lipid peroxidation. On the other hand, the kq value of the reaction of 12-(9-anthroyloxy)stearic acid with Cu2+ or I- was unaffected by lipid peroxidation. Based on these results, a localized change in the lipid fluidity of the membranes in association with lipid peroxidation has been discussed.

Animals↗

PubMed1986

Electron microscopic study of synaptic contacts between photoreceptors and HRP-filled horizontal cells in the turtle retina.

The synaptic contacts between photoreceptors and horizontal cells in the retina of the turtle (Geoclemys) were studied. Horizontal cells were classified into three types according to their intracellularly recorded spectral responses: luminosity, biphasic chromaticity, and triphasic chromaticity horizontal cells (LHC, BHC, and THC). These cells were then iontophoretically filled with horseradish peroxidase (HRP). The various types of photoreceptors located within the dendritic field of the HRP-filled horizontal cells were identified either as rods or as one of the three chromatic types of cones; the latter were identified by the presence and colors of their oil droplets in the inner segments. The synaptic contacts between photoreceptors and labeled horizontal cells were then investigated by light and electron microscopy of serial sections on three LHCs, two BHCs, and one THC. LHCs made synaptic contacts with about 100 photoreceptors, including rods and three chromatic types of cones; two-thirds of these photoreceptors contacted the cell body and the remaining its axon terminal. BHCs contacted about 30 cones; red-, green-, and blue-sensitive cones in the ratio of 3:4:1. THC contacted 20 cones; red- and blue-sensitive cones in the ratio of 2:1. The dendritic processes of HRP-filled horizontal cells were found as the lateral element of the ribbon synaptic complexes. The present finding suggests that the responses of BHC and THC to red flashes are fed directly from red-sensitive cones in addition to the feedback pathway of cone-horizontal cell connections in the previous studies.

Animals↗

PubMed1986

Horizontal cell signal is smaller with texture-like nonuniform patterns than with uniform fields of the same space-average illuminance.

While measurement of the pertinent response as a function of flash intensity has been a standard procedure in vision research, we ask here what happens to horizontal cells in the vertebrate retina if the flash energy is varied through the density of a large number of small light spots rather than through the intensity of uniform illumination. The experiment described here demonstrates that the electrical response of horizontal cells in the turtle retina is consistently smaller with the present dot-density modulation than with the usual intensity modulation, even though the comparison is made when the mean irradiance per photoreceptor is equal in the two methods of modulation. Thus, the spatial summation, an important retinal function often thought to provide a base signal level for contrast detection, is affected significantly by how the visual pattern is structured at a level of microscopic dimension far smaller than the receptive field. The present finding, which seems to be a new form of area-intensity effect, can be explained if the dendritic membrane conductance of horizontal cells at each synaptic site increases at a progressively higher rate with decreases of the corresponding local illuminance. This possibility is discussed in the light of relevant photoreceptor response data, the presumed sigmoidal trend of the postsynaptic chemosensitivity and a simple electrical analog of contiguous horizontal cells.

Animals↗

PubMed1986