Endogenous phosphorylation of retinal photoreceptor outer segment proteins by calcium phospholipid-dependent protein kinase

A calcium phospholipid-dependent protein kinase (C-kinase) activity was detected in the soluble fraction of rod outer segments (ROS) of the bovine retina. The enzyme required calcium, phosphatidylserine (PS) and diacylglycerol for maximal activity. In the presence of calcium and PS, C-kinase endogenously phosphorylated proteins with molecular weights of 95,000, 91,000, 31,000, 21,000, 19,000, 18,000, 16,000, 14,000 and 11,000. Addition of diolein in the reaction mixture further enhanced the endogenous phosphorylation of these proteins. Retinal was found to inhibit the phosphorylation of endogenous proteins by C-kinase in a concentration dependent manner. Half-maximal inhibition of enzyme activity was obtained at a retinal concentration of about 12μM. These results suggest that calcium, phospholipids and the C-kinase enzyme may play an important role in the functional regulation of rod photoreceptors and, with retinal, perhaps in the visual process as well.     

The pentylenetetrazol model of anxiety detects withdrawal from diazepam in rats

This experiment tested whether benzodiazepine withdrawal could be detected in an animal model of anxiety. Rats were trained in operant chambers using food reward to press one lever after pentylenetetrazol (PTZ), 20 mg/kg, injection and the other lever after saline injection. Previously, the PTZ cue has been shown to be simulated by anxiogenic drugs and blocked by anxiolytic drugs. After rats reliably performed this discrimination, they were injected with diazepam, 20 mg/kg, from 1 to 4 times a day for six days. For one group of subjects, on the third, fourth and sixth days, they were also injected with 40 mg/kg of RO 15-1788, a benzodiazepine receptor antagonist, and tested for lever selection: 50–80% of the subjects selected the PTZ lever; these results are in contrast to those obtained prior to chronic diazepam treatment in which RO 15-1788 did not generalize to PTZ. A second group of subjects was also injected for six days with diazepam and then allowed to withdraw spontaneously for eight days: PTZ lever selection over this period varied from 20 to 60% of rats. These data indicate that animals trained to discriminate a PTZ cue: 1) generalize the benzodiazepine withdrawal state to the PTZ cue, and 2) discriminate the withdrawal state for long periods of time, agreeing with clinical observations of long-lasting anxiety signs during benzodiazepine withdrawal.     

Discriminative stimulus properties of L-phenylisopropyl adenosine: blockade by caffeine and generalization to 2-chloroadenosine

Recent neurochemical data on the effects of activation and blockade of adenosine A1 receptors has suggested a direct role of adenosine in neurotransmission. The present research used a drug discrimination procedure to test the hypotheses that A1 adenosine receptor activation could serve as a discriminative stimulus and that caffeine, a drug believed to be an A1 receptor antagonist, could block the adenosine discrimination. Food-deprived rats were trained to press one of two levers on an FR 10 schedule of food-pellet delivery. Responses on one lever were reinforced following i.p. injection of N6 - (L-phenylisopropyl) adenosine (L-PIA); responses on the other lever were reinforced following i.p. injection of saline. L-PIA training dose was increased from 0.064 to 0.08 mg/kg L-PIA in the course of the study. Subjects required an average of 91 sessions to acquire this discrimination. Stimulus control by L-PIA was dose-dependent, with the ED-50 being approximately 0.03 mg/kg. 2-Chloroadenosine (2CA) generalized to L-PIA with a tenth the potency. Caffeine blocked L-PIA-induced lever selection. These results indicate that 1) rats can be trained to discriminate L-PIA from saline in a two-lever food-reinforced task and 2) the discriminative stimuli produced by L-PIA are based on its agonistic action at the adenosine A1 receptor.     

Clinical and experimental keratitis caused by the Colletotrichum state of Glomerella cingulata and Acrophialophora fusispora

Two cases of mycotic keratitis caused by the Colletotrichum state of Glomerella cingulata and Acrophialophora fusispora are reported for the first time. Both the isolates produced experimental corneal lesions in rabbit eyes but A. fusispora was more pathogenic. The experimental infection was more severe, with both the fungi, in rabbits pretreated with cortisone as compared with untreated animals. In vitro A. fusispora was most sensitive to miconazole and tolciclate followed by clotrimazole, amphotericin B and lactones while clotrimazole exerted maximum inhibitory effect on Colletotrichum followed by miconazole, lactones, amphotericin B and arnebins. Arnebins and tolciclate were inactive respectively against A. fusispora and Colletotrichum. Of the 3 drugs tested in vivo, against A. fusispora keratitis in rabbit, amphotericin B showed better results than tolciclate and miconazole.     

Oxo fatty acid esters from Cryptocoryne spiralis rhizomes

Two new compounds, isolated from the rhizomes of Cryptocoryne spiralis, have been characterized as ethyl 14-oxotetracosanoate and 15-oxoeicosanyl 14-oxoheptadecanoate by spectral data and chemical studies. Hentriacontane and sitosterol have also been isolated and identified.     

BCG-induced susceptibility of mice to challenge with Pseudomonas aeruginosa

Mice infected with Mycobacterium bovis, BCG, were shown to be highly susceptible to subsequent challenge with Pseudomonas aeruginosa. The susceptibility was characterized by the enhanced mortality and shortened survival after challenge with P. aeruginosa. BCG-treated mice did not show any enhanced susceptibility to challenge with Gram-positive bacteria such as Staphylococcus aureus or Listeria monocytogenes. BCG-treated mice eliminated P. aeruginosa from their organs in a pattern similar to that in untreated mice. There was no significant difference in the bactericidal activities of polymorphonuclear cells and macrophages between BCG-treated and untreated mice. An equal amount of endotoxin was detected by the Limulus lysate assay in the blood of both BCG-treated and untreated mice after challenge with P. aeruginosa. The enhanced susceptibility induced by BCG pretreatment could be decreased when the mice were rendered LPS-tolerant by injections of small amounts of LPS. These results suggest that BCG-induced susceptibility to P. aeruginosa can be ascribed to an enhanced susceptibility to the lethal effect of LPS produced by challenge bacteria, and not to the impairment of the ability to eliminate infected bacteria.     

Comparison of Beclomethasone Dipropionate Aerosol and Prednisolone in Reversible Airways Obstruction

This paper describes a double-bond crossover trial of prednisolone and beclomethasone dipropionate aerosol in 38 steroid-dependent patients with reversible diffuse airways obstruction. Altogether there was no difference in the patient''s preference of the two treatment groups or in the number of times they used their bronchodilator aerosol, or in the forced expiratory volume in one second, vital capacity, or peak expiratory flow rate in the two treatment groups. The plasma cortisol levels when the patients were on the aerosol were much higher than when they were on prednisolone. The use of inhaled aerosol steroids seems to be preferable as it eliminates the usual complications of oral steroid therapy.     

The Avena geo-curvature test

Summary The Avena geo-curvature test is a bioassay for auxin-type growth regulators. Etiolated oat coleoptiles are used and the test is conducted in special perspex trays under diffuse daylight. The coleoptiles, with the primary leaves intact, are arranged in grooves on the trays in 4 series of 6 coleoptiles each, and cut to a size of 10 mm. The test substance is applied on an agar strip covering only the lower halves of the apical cut surfaces of each series. After a 4-hour stay in the dark in moist Petri dishes the coleoptile cylinders are shadowgraphed on a 35-mm photographic film. The curvatures are measured from an enlarged projection (10 times natural size) of the shadowgraphs.The lowest IAA concentration which can be determined is around 30 to 60 g/l, i.e. about 1 to 2 ng IAA. The concentration response curves follow a logarithmic course up to 1,000 g/l. The standard error of the mean in a test series comprising 6 coleoptiles is on an average ± 7%. The simple and quick procedures make it possible for a worker to test 60 to 80 fractions a day.Dedicated to Professor Hans Söding on the occasion of his seventieth birthday. The senior author expresses his special gratitude for having been initiated by Professor Söding in the study of auxins.present address: Dpt. of Biology Princeton Univ. Princeton, N. J. 08540, U.S.A.