Extracellular production of singlet oxygen by stimulated macrophages quantified using 9,10-diphenylanthracene and perylene in a polystyrene film

The extracellular production of singlet oxygen (O2(1 delta g)) by stimulated macrophages was measured using a modification of our quantitative method initially developed to measure the intracellular production of O2(1 delta g) by neutrophils (Steinbeck, M. J., Khan, A. U., and Karnovsky, M. J. (1992) J. Biol. Chem. 267, 13425-13433). Glass coverslips were coated with the specific chemical trap for O2(1 delta g), 9,10-diphenylanthracene (DPA) and perylene, which is an internal standard, in a methylene chloride solution containing 0.3 mg/ml polystyrene. On evaporation, the polystyrene formed an even coating of DPA and perylene over the surface of a glass coverslip (PDP film). Unstimulated macrophages or macrophages stimulated with 4 beta-phorbol 12-myristate 13-acetate (PMA) or formyl-methionyl-leucyl-phenylalanine (fMLP) were then added to the PDP film in a darkened room and incubated at 37 degrees C for 30 min in a humidified 5% CO2 atmosphere. Both unstimulated and stimulated cells adhered to the PDP film in approximately equivalent numbers. Only stimulated cells produced measurable amounts of O2(1 delta g) in a dose-dependent response to either PMA or fMLP. The production of O2(1 delta g) by macrophages stimulated with PMA was maximal in response to 25 ng, 17.8 +/- 1.3 nmol of O2(1 delta g)/approximately 1.00 x 10(6) cells. The maximal response for fMLP was at a concentration of 1 microM, 18.4 +/- 1.0 nmol of O2(1 delta g)/approximately 1.00 x 10(6) cells. The specific detection of O2(1 delta g) by this method was confirmed by thermally releasing O2(1 delta g) from the DPA-O2(1 delta g) reaction product, DPA-endoperoxide, regenerating the original DPA compound. Production of O2(1 delta g) by the stimulated cells was inhibited 80-89% by the addition of 60-120 micrograms of superoxide dismutase, an enzyme that converts superoxide to hydrogen peroxide and ground state molecular oxygen or 79-84% with the addition of 2 mM histidine, an avid quencher of O2(1 delta g). Neither of these additions interfered with adhesion of the cells to the PDP film. The ability of superoxide dismutase to inhibit the production of O2(1 delta g) suggested that O2(1 delta g) was produced via a superoxide-dependent route. The ability of an oxidase to produce O2(1 delta g) secondary to superoxide production was substantiated further using a xanthine oxidase-acetaldehyde system. Purified xanthine oxidase produced both superoxide and O2(1 delta g), and their production was inhibited by the addition of superoxide dismutase.(ABSTRACT TRUNCATED AT 400 WORDS)

Spermine and spermidine protection of plasmid DNA against single-strand breaks induced by singlet oxygen

Oxidative damage to DNA induced by singlet molecular oxygen (1O2*) includes single-strand breaks, which the biologically occurring 1O2* quenchers spermine and spermidine are shown to prevent. These polyamines at a physiological concentration (10 mM) reduce the percentage of the open circular form of pBR322 plasmid DNA, which is generated at the expense of the native supercoiled form when the plasmids are incubated with a chemical source of 1O2*, the water-soluble endoperoxide of 3,3'-(1,4-naphthylidene)dipropionate. Spermine and spermidine can be expected to protect DNA against other damaging effects of 1O2*.

A proposed function for spermine and spermidine: protection of replicating DNA against damage by singlet oxygen

Like all aliphatic amines, the polyamines spermine and spermidine are physical quenchers of singlet molecular oxygen (1O2*). The rate constants of these processes were determined in vitro with photochemically generated 1O2* and the hydrocarbon rubrene as substrate, in pyridine. At millimolar concentration, spermine and spermidine should quench 1O2* in vivo and prevent it from damaging DNA. It is proposed that a biological function of polyamines is the protection of replicating DNA against oxidative damage.

Intracellular singlet oxygen generation by phagocytosing neutrophils in response to particles coated with a chemical trap

To determine if singlet oxygen (O2(1 delta g)) is produced by neutrophils (PMNs) during the process of phagocytosis, glass beads were coated with a specific chemical trap for O2(1 delta g), 9,10-diphenylanthracene (DPA). Singlet oxygen, but not other reactive oxygen species, reacts rapidly with DPA at a rate of kr = 1.3 x 10(6) M-1 s-1 to form a stable product, DPA-endoperoxide (Corey, E. J., and Taylor, W. C. (1964) J. Am. Chem. Soc. 86, 3881-3882; Wasserman, H. H., Scheffer, J. R., and Cooper, J. L. (1972) J. Am. Chem. Soc. 94, 4991-4996; Turro, N. J., Chow, M.-F., and Rigaudy, J. (1981) J. Am. Chem. Soc. 103, 7218-7224). The production of DPA-endoperoxide was determined by ultraviolet spectroscopy as a decrease in DPA absorbance at 355 nm. The absorbance of DPA was normalized to the absorbance of perylene, which was included in the coating on the beads as a nonreactive, internal standard. In the present study, DPA- and perylene-coated beads were initially allowed to adhere to fibronectin-coated coverslips. PMNs were then added to the bead-coated coverslips and allowed to adhere and phagocytose the beads for 1 h at 37 degrees C. In some experiments, 4B-phorbol-12-myristate-13-acetate (PMA) (1 ng/2.5 x 10(7) cells/ml), a known activator of the PMN NADPH-oxidase, was added as a co-stimulant. The amount of O2(1 delta g) produced by phagocytically stimulated PMNs was calculated to be 11.3 +/- 4.9 nmol of O2(1 delta g)/1.25 x 10(6) cells. Low dose PMA co-stimulation increased the production of O2(1 delta g) to 14.1 +/- 4.1 nmol/1.25 x 10(6) cells. Averaged together these amounts represent approximately 19 +/- 5.0% of the total oxygen consumed by PMNs in response to DPA- and perylene-coated beads. The specificity of the DPA reaction with O2(1 delta g) was confirmed by warming to 120 degrees C, which releases O2(1 delta g) from the DPA-endoperoxide, regenerating the parent DPA compound (Wasserman et al., 1972; Turro et al., 1981) and the absorbance at 355 nm. In addition, beta-carotene, an avid quencher of O2(1 delta g), was included in the coating of some bead preparations; assays in which these beads were used showed no change in the absorbance at 355 nm. Singlet oxygen production by myeloperoxidase was also measured using the coated bead assay and the results suggest that this is a major pathway by which singlet oxygen is generated in phagocytically stimulated PMNs.(ABSTRACT TRUNCATED AT 400 WORDS)

Polysomnographic findings in adolescents with major depression

Ten adolescents with major depression and 10 age-matched controls were studied with polysomnography for 3 consecutive nights. The sleep records were analyzed for variables pertaining to sleep continuity (total sleep time, sleep efficiency, sleep onset latency, number of awakenings, and number of stage shifts), sleep architecture (Stages 1, 2, 3, and 4), and rapid eye movement (REM) sleep (total) REM sleep time, number of REM periods, REM latency, and REM density). The experimental and control groups were compared on 14 variables with the t test for independent groups. The results indicated that none of the sleep variables differed significantly between the two groups. These results confirm earlier findings indicating that the abnormalities in REM latency and REM density that characterize adults with major depression are absent in adolescents suffering from major depression. Developmental and diagnostic variables are discussed as possible explanations for the sleep differences between adolescents and adults with depressive disorders.

Near infrared emission of singlet oxygen generated in the dark

Singlet oxygen generation is reported from (1) enzymatic reaction and (2) electron transfer reactions of the superoxide anion measured directly with an ultrasensitive near-IR emission spectrophotometer by monitoring the O2(1 delta g)----O2 (3 sigma g-) transition at 1268 nm. Near-IR emission spectra from the myeloperoxidase and lactoperoxidase enzymatic systems show only emission of singlet oxygen at 1268 nm. The lipoxygenase/Na-linoleate enzymatic reaction exhibits two emissions, 1268 nm and 1288 nm. The latter emission is identified as originating from a peroxy radical. Spectral and kinetic data giving evidence of singlet oxygen generation is obtained from the reaction of potassium superoxide solubilized by 18-crown-6-ether in acetonitrile with a series of organometallic coordination compounds.

Sensitivity and specificity of TRH stimulation test in depressed and nondepressed adolescents

The thyrotropin-releasing hormone (TRH) stimulation test was carried out in 100 acutely hospitalized adolescents (ages 13-17 years) with a variety of diagnoses. The test was positive (delta max thyrotropin less than or equal to 7 microIU/ml) in 36.6% of adolescents with major depression, 20.8% with conduct disorders, 17% with adjustment disorders, and 43% with substance abuse disorders. A X2 analysis of the data showed no significant difference among these four diagnostic groups. The test was negative in adolescents with attention deficit disorder and dysthymic disorder. Comparison of the six diagnostic groups with regard to the amount of thyrotropin (thyroid-stimulating hormone, TSH) response to TRH stimulation indicated that the groups with major depression and substance abuse disorders had significantly lower values of delta max TSH than the other groups. TSH values did not differ significantly between males and females. Similarly, there were no significant age differences (younger adolescents vs. older adolescents).

Water induced dismutation of superoxide anion generates singlet molecular oxygen

Direct spectroscopic measurement of 1268 nm singlet oxygen emission from KO2 suspensions at room temperature in three non-protonic solvents--CCl4, Cl2FCCClF2, and C6F14 by the action of water is reported. The results clearly show that the singlet oxygen generation is due to a water induced reaction, and suggest that one role of the enzyme superoxide dismutase may be the protection of biological structures, for example, lipid membranes, from degradation by singlet oxygen.

Comparison of a long-acting form of propranolol and conventional propranolol in the treatment of hypertension in elderly patients

Nineteen elderly hypertensive patients already being treated with a diuretic and, where necessary, another anti-hypertensive agent, were studied in a double-blind, randomized, crossover comparison of conventional propranolol, 40 mg three times daily, with a long-acting propranolol formulation, 160 mg once daily, as a second line agent. Patients were assessed before taking the morning's allocated medication. This was done as near as possible to 24 h after the last dose of once daily propranolol and as near as possible to 15 h after the last dose of three times daily conventional propranolol. Assessment was carried out at the time of randomization and after 4 weeks' treatment with both propranolol formulations. Heart rate and blood pressures were measured in the supine and standing positions and after exercise. Both propranolol formulations were effective as second line agents in these elderly patients and both were well tolerated. Patient compliance on both propranolol formulations was very good although the long-acting formulation may be of value in improving this still further.

Antiarthritic gold compounds effectively quench electronically excited singlet oxygen

Although certain gold [Au(I)] compounds have been used effectively in the treatment of rheumatoid arthritis for some years, the molecular basis for such therapeutic action has been unclear. One possible mechanism of the action of Au(I) compounds is that they protect unsaturated membrane lipids and proteins against oxidative degradation caused by activated phagocytes that are not properly regulated. In this study it has been shown that superoxide ion (O-2.), a product of activated phagocytes, can be oxidized to electronically excited singlet oxygen (O1(2)delta g), an agent that is capable of peroxidation of unsaturated fatty acid derivatives. It has also been shown that antiarthritic Au(I) compounds are effective deactivators of O1(2)delta g with quenching constants on the order of 10(7) M-1 sec-1.

Phototoxicity of the tetracyclines: photosensitized emission of singlet delta dioxygen

The spectroscopic observation of 1268-nm emission of singlet oxygen photosensitized by tetracyclines in oxygenated solutions at room temperature is reported. In the series demeclocycline, tetracycline, and minocycline, the efficiency of singlet oxygen generation is found to parallel the clinical observation of relative frequency of phototoxicity of these antibiotics, suggesting singlet oxygen generation as the origin of their phototoxicity.

Effect of naloxone on the respiratory responses to hypoxia in chronic obstructive pulmonary disease

Ventilatory and airway occlusion pressure responses to hypoxia were measured in 7 subjects with chronic obstructive pulmonary disease (COPD). Paired responses were obtained after the administration of saline or naloxone and, on separate days, in 5 of the 7 subjects, after 2 saline injections. Naloxone increased (p less than 0.05) the mean inspiratory flow and the ventilatory and airway occlusion pressure responses to hypoxia when compared with the saline responses. Resting ventilation and tidal volume also increased, but not significantly. Involvement of endogenously generated opioid substances in the control of breathing of patients with COPD is further suggested by this study.

Myeloperoxidase singlet molecular oxygen generation detected by direct infrared electronic emission

Myeloperoxidase in micromolar concentrations reacting with half-millimolar stock solution H2O2 in acetate buffer containing KBr and in 50% D2O (pH + pD = 4.5) at 298 K is shown to generate singlet delta molecular oxygen efficiently. The near infrared electronic emission of singlet oxygen at 1268 nm is detected directly by novel ultrasensitive IR spectrophotometer equipment. The quantum efficiency of singlet oxygen generation by the MPO X Br- X H2O2 reaction is shown to be comparable with that of the standard chemical reaction OCl- X H2O2 at identical peroxide concentrations.

L-ascorbic acid quenching of singlet delta molecular oxygen in aqueous media: generalized antioxidant property of vitamin C

L-ascorbic acid quenches singlet (1 delta g) molecular oxygen in aqueous media (pH 6.8 for [1H]H2O and pD 7.2 for [2H]D2O) as measured directly by monitoring (0,0) 1 delta g leads to 3 sigma-g emission at 1.28 micron. Singlet oxygen was generated at room temperature in the solutions via photosensitization of sodium chrysene sulfonate; this sulfonated polycyclic hydrocarbon was synthesized to provide a water soluble chromophore inert to usual dye-ascorbate photobleaching. A marked isotope effect is found; kHQ2O is 3.3 times faster than kDQ2O, suggesting ascorbic acid is chemically quenching singlet oxygen.

Nonoperative management of bladder rupture from external trauma

Nonoperative (catheter) management was used in 18 patients with extraperitoneal rupture of the bladder with limited extravasation of dye found by retrograde cystogram. Complications occurred in 4 of the 18 patients. A review of the literature shows a 20 to 25-per cent complication rate with nonoperative management of bladder rupture. However, with a small extraperitoneal rupture with limited extravasation, especially in a female, the nonoperative (catheter) management will give a satisfactory result.

Sleep REM latency in hyperkinetic boys

This study compared the sleep-cycle characteristics of 16 hyperkinetic boys with those of 12 normal boys. The results indicated no differences between the two groups, with one exception: a subset of the hyperkinetic children had markedly short REM latencies.

Neonatal perirenal urinary extravasation with posterior urethral valves

Renal dysplasia and atrophy are associated with congenital urinary tract obstruction, such as posterior urethral valves, and are thought to result from the increased pressure in the developing obstructed urinary system. This increased pressure is likely to be alleviated by perirenal urinary extravasation and urinary ascites. Whether this relief of pressure in the obstructed developing kidney results in a lessened degree of renal abnormality is likely to depend on the time during the period of gestation when the urinary leak occurs and the degree of renal dysplasia and atrophy at the time of the urinary leak.

A comparison of the therapeutic and cardiovascular effects of a single nightly dose of Prothiaden (dothiepin, dosulepin) and Lentizol (sustained-release amitriptyline) in depressed elderly patients

This was a single-blind 4-week parallel group comparative trial in fifty depressed patients. Twenty-five patients received 50 mg of Lentizol, a sustained-release form of amitriptyline, and twenty-five received 75 mg of Prothiaden. Both groups took their drugs as a single night-time dose. Patient response was measured on a symptom check-list which was completed by the doctor and a self-rating depression scale. Tolerance was assessed by recording volunteered and observed side-effects and also by taking the pulse, blood pressure and an electrocardiogram before treatment and after 2 and 4 weeks. A statistically better response was seen with Prothiaden at each follow-up assessment (1, 2 and 4 weeks) compared to Lentizol as measured by both the symptom check-list and the self-rating scale. Less side-effects was also seen with Prothiaden. Minor changes were seen in the ECG records of two patients on Prothiaden and three on Lentizol. These changes were not associated with any clinical change in the patients' cardiovascular state. No consistent changes of any clinical significance were seen in the pulse and blood pressure recordings.