Stabilisation of refraction following cataract surgery.

Refraction was performed at frequent, regular intervals for six months following routine intracapsular cataract extraction. Patients were divided into two groups, those whose limbal sections were closed with 8-0 virgin silk or with 9-0 nylon. The stabilisation of refraction was observed, and the most suitable time to prescribe 'first glasses' was estimated retrospectively. In the silk group this was found to be at three months in the nylon group at four months. However, results in the latter were less predictable with greater variation.     

Clinical findings and common symptoms in retinitis pigmentosa

Data analysis was performed in a prospective study of clinical symptoms and findings in 500 patients with retinitis pigmentosa. The symptoms and findings in these patients met the usual definitions of the disease. At initial examination the patients were questioned in a standardized manner; symptoms and associated health problems were reviewed. Some patients were unable to answer all of the questions. Of the patients 274 (55%) were men and 226 (45%) were women, with a race distribution of 21 (4%) black, 47 (9%) Hispanic, 26 (5%) Oriental, three (1%) American Indian, and 403 (81%) white. Sixty-nine patients reported no symptoms of night blindness and 116 patients claimed no visual field changes; 90 stated that they saw better at dusk. The most common problem noted by 263 (53.3%) was headaches, 31 on a daily basis, 42 at least weekly, 124 infrequently, and the remainder nonspecifically. Numbness or tingling, mainly in extremities, was reported by 99 patients. The second most common problem affecting 170 patients (34.6%) was light flashes; since eight patients had retinal detachments, light flashes cannot be totally discounted. Of 143 patients who had been pregnant, 14 had visual changes.     

Clinical pharmacokinetics of midazolam in intensive care patients, a wide interpatient variability?

The pharmacokinetics of midazolam and its metabolites were studied in 17 patients on mechanical ventilation in a general intensive care unit who were receiving a continuous intravenous infusion of midazolam, adjusted according to the level of induced sedation. Three patients were studied twice. Serum midazolam and alpha-hydroxymidazolamglucuronide levels were determined during and after infusion. The sedation level was scored on a four-point scale. Half of the observed patients were still drowsy or asleep 10 hours after termination of midazolam infusion. In only one patient was midazolam serum elimination half-life less than 2 hours and in six patients the half-life was greater than 10 hours. A wide range of midazolam serum levels was associated with adequate sedation, and similarly the midazolam levels at the moment of awakening were highly variable. The serum concentration ratio of midazolam/alpha-hydroxymidazolamglucuronide at the end of the infusion varied from 0.03 to 15.6. Renal function could account for only a part of this variation.     

Evidence for nitric oxide participation in down-regulation of CYP2B1/2 gene expression at the pretranslational level

Septic or inflammatory stimuli suppress drug metabolism by cytochrome P-450 in the liver, presumably at the pretranslational level. We have shown previously that nitric oxide is responsible at least in part for the inhibition by bacterial lipopolysaccharide of phenobarbital-induced CYP2B1/2 activity in vivo. This was attributed to the interaction of nitric oxide with heme in the active-center of cytochrome P450, leading to enzyme inactivation. Here, we report of nitric oxide with heme in the active-center of cytochrome P450, leading to enzyme inactivation. Here, we report that endogeneous nitric oxide also contributes to LPS-induced suppression of CYP2B1/2 in vivo by down-regulating the expression of CYP2B1/2 protein and mRNA.     

Treatment with desmopressin in severe nocturnal enuresis in childhood

A series of 22 patients with severe nocturnal enuresis were treated with desmopressin in a randomised double-blind cross-over study. Treatment with 20 and 40 micrograms was highly effective compared with placebo. No difference in dry nights was found between the 2 dosages. Desmopressin proved to be a safe and effective treatment.     

Particles from dialysis tubing stimulate interleukin-1 secretion by macrophages

Loading of tissue macrophages with dialysis-tubing-derived particles may occur during chronic haemodialysis. Previous studies have demonstrated that these particle-laden macrophages release significant quantities of prostaglandins. In these experiments, the effects of dialysis-tubing-particle loading on the release of the central inflammatory mediator, interleukin 1 (IL 1), was examined. Rats received daily injections of silicone or polyvinylchloride (PVC) particles, and were compared to animals given saline alone. The silicone and PVC groups received a total of 3 x 10(9) particles over a 4-week period. Non-stimulated peritoneal macrophages from control animals released a median of 4.1 (range 1.2-10.3) U IL 1 per 10(6) cells. In contrast, macrophages from silicone- and PVC-loaded animals spontaneously released high levels of IL 1 (median 21.8; range 10-36.7) and 94 (range 36-336) U per 10(6) cells respectively). Following in vitro stimulation with bacterial lipopolysaccharide (LPS), peritoneal macrophages from silicone- and PVC-treated animals released large amounts of IL 1 (median 538 (range 359-2017) U and median 653 (range 326-1134) U per 10(6) cells, respectively) as compared to LPS-stimulated macrophages from control animals (median 332 (range 130-306) U per 10(6) cells]. Zymosan or LPS stimulation of splenic cells from silicone- and PVC-loaded animals also secreted increased quantities of IL 1 as compared to controls. The chronic loading of tissue macrophages in dialysis patients with tubing-derived particles may result in augmented release of IL 1, with subsequent activation of inflammatory processes.     

A case of primary lymphoma of the rectum

The Authors describe a case of primary rectal lymphoma. The primitive involvement of this area is infrequent. The Authors emphasize the difficulty of preoperative diagnosis. The therapeutic approach should allow for correct staging which is only obtained by means of diagnostic studies aimed at excluding multicentric localisation. Sensitivity to radiotherapy has led the Authors to propose it as primary treatment, at least in stage I; surgery must be considered elective in stage II or in cases of need. Chemotherapy is indicated alone or in association with radiotherapy or surgery.     

The effect of currently available contact lens disinfection systems on Acanthamoeba castellanii and Acanthamoeba polyphaga

Contact lens disinfection systems were evaluated for their effectiveness in killing Acanthamoeba castellanii and Acanthamoeba polyphaga trophozoites and cysts. Amoebae were inoculated into commercially available contact lens cleaning and soaking solutions. At intervals varying from 30 minutes to 24 hours, solutions were filtered. The filters were removed and cultured for Acanthamoeba organisms. Striking differences were observed in the abilities of the different disinfecting solutions to kill the organisms. Solutions containing chlorhexidine were effective at very short exposure times. Solutions containing benzalkonium chloride required slightly longer exposure times but were faster than solutions containing only thimerosal. Solutions containing sorbate, polyaminopropyl biguanide, or polyquaternium-1 were not effective at killing Acanthamoeba organisms in the time allotted for the experiment. Solutions containing hydrogen peroxide were quite effective if the agent was not prematurely catalyzed. A. polyphaga generally required longer exposure to disinfectants than did A. castellanii for complete inhibition to occur.