Prospective comparison of single-zone and multizone laser in situ keratomileusis for the correction of low myopia

OBJECTIVE: This study aimed to determine whether there is a true difference in predictability between single-zone and multizone laser in situ keratomileusis (LASIK) for the correction of low myopia or whether any difference in predictability is because of a need for separate clinical nomograms for the two treatments. DESIGN: A prospective, randomized, clinical trial. PARTICIPANTS: Fourteen surgeons and 190 eyes of 95 patients with myopia who desired surgical correction of myopia ranging from -2.00 to -7.00 diopters (D) participated. INTERVENTION: Fellow eyes of patients with myopia undergoing bilateral simultaneous LASIK were randomized to single-zone and multizone ablation. Astigmatism was not corrected at the time of LASIK. MAIN OUTCOME MEASURES: Predictability, postoperative videokeratography, and contrast sensitivity were assessed at 3 months after surgery. RESULTS: At 3 months, r2 values relating laser setting to change in spherical equivalent refraction were 0.78 for single-zone and 0.76 for multizone ablation; mean outcome with respect to intended was -0.84 D (0.65 standard deviation [SD]) for single-zone and -0.62 D (0.78 SD) for multizone eyes (P = 0.035). There was no relationship between single-zone and multizone ablation and the likelihood of asymmetric postoperative videokeratography (P = 0.83). The only difference in contrast sensitivity was a significantly greater decrease in log contrast for multizone eyes at 12 cyc/deg under undilated conditions. CONCLUSIONS: There is no true difference in predictability between single-zone and multizone LASIK for the correction of low myopia. Separate clinical nomograms for single-zone and multizone LASIK should eliminate the difference in predictability that was observed in this clinical trial.     

Health risk of coplanar polychlorinated biphenyl congeners in edible fish from the Mediterranean Sea

The muscle tissue of different species of fish was analyzed for polychlorinated biphenyls (PCBs) in order to estimate the daily intake of these contaminants. Contamination levels among the different species varied between 108 and 678 ng/g lipid weight. Isomer-specific analysis in the muscle tissue of the various fish revealed a profile dominated by hexa- and pentachlorobiphenyls, followed by hepta- and tetrachlorobiphenyls. Other congeners, including those with fewer than four or more than nine chlorine atoms, were below the instrumental limit of detection in all samples. PCB dietary intake was below the range of 1 to 4 pg 2,3,7,8-tetrachloro-p-dioxin equivalents per kg body weight per day set by the World Health Organization. From a public health point of view, there is no indication of important risks associated with the consumption of these seafoods.     

Systemic animal external parasiticidal activity of perfluoroalkylbenzimidazoles and their aminoanilide precursors

In vitro and in vivo efficacy data indicate that chemical activity is optimized at the 2 carbon chain length and that these compounds have injectable potency and spectrum of activity against major animal external parasite species.     

Elevated serum levels of the eosinophil granule major basic protein in patients with eosinophilia

A radioimmunoassay was established for the human eosinophil granule major basic protein (MBP). The mean level of MBP in sera from 105 normal control patients was 454 ng/ml, whereas in a sample of 188 patients with various forms of diseases, including the hypereosinophilic syndrome, levels as high as 14,000 ng/ml were measured. Serum levels of MBP did not correlate with eosinophil counts in normal subjects, but a positive correlation was seen in patients with eosinophilia; the patients with eosinophil counts greater than 350/mm3 generally showed increased levels of MBP. Many patients with skin disease and normal eosinophil counts had elevated levels of serum MBP. Monomer MBP has a molecular weight of 9,300, but in sera of patients with eosinophilia, the MBP activity was of high molecular weight, greater than 50,000. Analyses of serum by Sephadex G-200 and by electrofocusing suggest that MBP is not simply polymerized, but rather is bound to a larger carrier molecule. Monomeric MBP can be isolated from serum by reduction of serum with dithiothreitol, alkylation with iodoacetamide, and acidification to pH 2 followed by fractionation on Sephadex G-50 at pH 2. Under these conditions, up to 80% of the MBP emerges in monomeric form. The results indicate that eosinophil granule proteins circulate in blood covalently bound to serum proteins, and that elevated concentrations of serum MBP are present in some diseases associated with eosinophilia.     

Clinically unsuspected malignant melanomas of the posterior uvea (author's transl)

Out of 1300 eyes enucleated between 1966-1974, 300 subsequently revealed histologically-proved malignant melanomas of the uvea. In 264 cases the clinical diagnosis was correctly made. In 36 cases the i.o. malignant melanomas were clinically unsuspected. The incorrect clinical diagnoses included: secondary glaucoma (30), retinal detachment (2), iritis (2), and end/panophthalmitis (2). The clinical symptomatology and morphology of the secondary glaucoma caused by the i.o. melanomas did not differ from that due to other, non-neoplastic etiologies. In almost all of the 36 cases the eyes revealed unilateral severe opacity of the media. It is important that one consider an intraocular melanoma in cases of secondary glaucoma, retinal detachment, or intraocular inflammation in which the etiology is uncertain. This is also true in cases of blind, painful eyes in which there is no obvious etiology. Early diagnosis is of vital interest to the patient because this group, in which the malignant melanoma was unsuspected, may be, as suspected in this study, is characterised by extreme aggressivness and invasive capacity. One third of these eyes revealed extension of tumor through the sclera and optic nerve. Also these tumors often revealed more malignant cell types.     

The influence of extracellular calcium on muscarinic receptors in vascular smooth muscle

The time course and mechanism of vulnerability to ventricular fibrillation (VF) a 10-minute occlusion of the left anterior descending coronary artery and following its release were studied in 48 dogs. VF threshold was determined by inducing a sequence of three extrasystoles (sequential R/T pulsing). Within 1 minute of occlusion, the fibrillation current decreased to the level required for eliciting a propagated diastolic response. This state of enhanced vulnerability lasted for approximately 6 minutes, after which the VF threshold returned to preocclusion values. The vulnerability changes upon reperfusion, by comparison, occurred within seconds of release and persisted only transiently. Three minutes of occlusion was the minimal time which resulted in a reduction in VF threshold after release. Alpha and beta-adrenergic blockade with phentolamine and propranolol, respectively, prevented the decrease in VF threshold during occlusion but were without effect upon threshold changes during coronary artery release. Lidocaine failed to alter the pattern of vulnerability. It is concluded that adrenergic mechanisms play a key role in the increased susceptibility to VF associated with acute myocardial ischemia, whereas the changes in VF threshold following reperfusion may be due to washout products of cellular ischemia. These findings support the view that protection against VF during coronary artery occlusion and release may require different antiarrhythmic measures.