Diisopropylfluorophosphate alters retinal neurotransmitter levels and reduces experimentally-induced myopia.

The excessive enlargement of the eye seen in myopia is known to be regulated, in part, by retinal neurotransmitters. One excitatory retinal neurotransmitter, acetylcholine, has been implicated in the signal cascade through the effectiveness of the muscarinic antagonist, atropine, in preventing myopia development. The present study therefore examined whether an indirect cholinomimetic, diisopropylfluorophosphate (DFP), could increase the level of experimental myopia, induced by the deprivation of pattern vision. Injections of either phosphate-buffered DFP or phosphate-buffered saline were made every 48 h into the vitreous chamber of one eye of chicks. The injected eye was then deprived of pattern vision by a translucent occluder. The fellow eye remained untreated and acted as a genetic control. At the end of the treatment period (8 days) axial ocular dimensions and cycloplegic refractive error were measured. To investigate the effects of DFP on retinal neurotransmitter levels, measurements of acetylcholine and dopamine contents were made on retinal tissue following either a single or multiple DFP injections, using reverse phase high performance liquid chromatography (HPLC). Rather than potentiating myopia and vitreous chamber elongation, a significant reduction in myopia (58%) was observed in DFP-injected deprived eyes, compared to saline controls. However, open eyes injected with DFP showed no difference in refraction or vitreous chamber depth compared to contralateral control eyes or saline controls. HPLC analysis revealed increased steady-state content of acetylcholine (+34 +/- 6 ng/mg protein, mean +/- SEM, P<0.01, equivalent to a 54% increase) and dopamine (+377 +/- 83 pg/mg protein, P<0.01, a 36% increase) in DFP-treated eyes compared to contralateral control eyes following a single DFP injection. No changes in either acetylcholine or dopamine content were found in saline-treated control animals. Injection of dopamine antagonists, in combination with DFP, indicated that the DFP-induced reduction in myopia is mediated, at least in part, through a D2 receptor mechanism. Findings argue against a direct cholinergic 'stop-go' pathway controlling ocular growth. Instead the reduction of induced myopia could be related to the action of DFP (directly or indirectly) on dopamine levels in the retina.

Efficacy and tolerability of the specific cyclooxygenase-2 inhibitor DFP compared with naproxen sodium in patients with postoperative dental pain.

DFP [3-(2-propyloxy)-(4-methyl-sulfonylphenyl)-(5,5-dimethyl)-fu ranone] is a highly specific cyclooxygenase-2 inhibitor (>2500-fold selective in transfected Chinese hamster ovary cell assays) that has demonstrated efficacy in preclinical models of pain and inflammation. The present single-dose, randomized, double-masked, double-dummy, placebo-controlled, parallel-group study was undertaken to compare DFP 5, 25, and 50 mg with naproxen sodium 550 mg and with placebo in 196 patients (mean age, 25.8 years; 187 [95.4%] males) who experienced moderate-to-severe pain after surgical removal of > or =2 third molars. Overall analgesic effect, duration of effect, time to onset of analgesic effect, peak analgesic effect, and tolerability were assessed over a 24-hour postdose period. Both DFP 25 and 50 mg, as well as the active comparator, naproxen sodium 550 mg, were significantly more effective than placebo. The onset of analgesic effect in the DFP 25-mg, DFP 50-mg, and naproxen sodium 550-mg groups did not differ significantly. DFP was generally well tolerated in single doses up to 50 mg. DFP 50 mg was efficacious in the treatment of postoperative dental pain and was indistinguishable from the active comparator, naproxen sodium 550 mg.

Field bean protease inhibitor preparations, unlike methotrexate, can completely suppress Yoshida sarcoma tumor in rats.

Protease inhibitor preparations (PIP) with antitryptic and antichymotryptic activities, isolated from field bean legume as well as doxorubicin and cyclophosphamide could effectively suppress the growth of Yoshida sarcoma ascites tumor cells transplanted in adult rats and prevent their death. As against this, methotrexate and heat-inactivated PIP were ineffective in such rats at varied doses of treatment tried. The percent survival of animals appeared to be related to the purity, treatment mode and the dose of PIP used. Zymographic analysis of the trypsin activated sarcoma cell homogenate revealed the presence of six protease bands in the molecular weight range of 51kD to 206kD. Prolonged interactions of such zymograms with protease inhibitors such as 20mM EDTA or 5mM diisopropyl flurophosphate (DIFP) or 400 micrograms/ml of PIP in reaction buffer indicated that these are not metalloproteases but serine proteases whose activities are inhibited by PIP and DIFP. Since proteases are involved in cell growth regulation and cell transformation, we hypothesize a positive relationship between the field bean protease inhibitor's blocking action on tumor cell proteases and its tumor suppressing activity.

[The total proteolytic and collagenolytic activity in the blood cells of patients with systemic scleroderma]. / Izuchenie obshchei proteoliticheskoi i kollagenoliticheskoi aktivnosti v kletkakh krovi bol'nykh sistemnoi sklerodermiei.

Collagenolytic (CA) and neutral caseinolytic activity (NCA) was studied in extracts from blood cells (neutrophils, mononuclear cells and platelets) of patients suffering from systemic scleroderma (SSD). 23 persons were examined. Of these, 15 had local skin lesions, 8 diffuse lesions. CA, both specific and per 10(6) cells was found to be dramatically decreased (2-4-fold) in all blood cells, whereas NCA was increased in neutrophils and mononuclear cells; in platelets, it remained within normal. The amount of protein in neutrophils and mononuclear cells was lowered 1.2 and 2-fold respectively. In diffuse skin lesions, the amount of protein in cells was lower than in local lesions. It should be noted that in SSD patients examined, the inflammatory process was unmarked. Therefore, the data on substantial changes in proteolytic activity cannot be related to the inflammatory process. A reverse correlation was established between CA in neutrophils and circulating immune complexes as was a reverse correlation between CA in mononuclear cells and blood antinuclear factor. The data presented indicate that proteinases are an important factor of the pathogenesis in SSD. Apparently, SSD is characterized not only by enhanced synthesis of collagen but also by a dramatic reduction of the activity of enzymes that specifically hydrolyze this group of proteins, which leads to a decrease of collagen catabolism and hence, to the development of fibrosis in tissues.

Gradual increase in the sensitivity of extraocular muscles to acetylcholine during topical treatment of rabbit eyes with isoflurophate.

During the course of four to 14 days of topical application of isoflurophate ointment to rabbit eyes, there was a gradual increase in the sensitivity to acetylcholine of the superior recti muscles of treated eyes in vitro in the absence but not in the presence of eserine. The development of increased sensitivity to acetylcholine was accelerated when isoflurophate was applied twice daily. This increased sensitivity to acetylcholine was maintained when, after two weeks of twice-daily isoflurophate treatment, the frequency of administration was decreased to two applications per week. Partial reversal of this effect occurred seven to 14 days after the last isoflurophate treatment.