[Visual function with blue light filter IOLs]. / Visuelle Funktion mit Blaulichtfilter-IOL.

BACKGROUND: Recently, intraocular lenses (IOLs) with a blue light filter have been introduced to protect the retina from age-related macular degeneration (AMD) after cataract extraction. A reduction of longitudinal chromatic aberration by filtering blue light may enhance patient's visual function. In this study we compared subjective and objective parameters of visual function following implantation of blue light filter (yellow) IOLs and IOLs of the same design without filter. PATIENTS AND METHODS: 21 patients (21 eyes) underwent implantation of an IOL with a blue light filter (AF-1 UY, Hoya, Japan), 22 patients (22 eyes) received an IOL without blue light filter (AF-1 UV, Hoya, Japan). Patients were examined three months postoperatively for uncorrected and best corrected spectacle visual acuity, mesopic and photopic contrast sensitivity, colour vision and subjective quality of vision by a standard questionnaire. RESULTS: Eyes with blue light filter IOLs did not show any significant difference in any parameter analysed when compared to eyes without the blue light filter IOL. Subjective quality of vision was considered to be high by all patients and no significant difference was observed between the two IOL groups. CONCLUSION: The visual function of patients with blue filter IOLs is not significantly different to those without blue light filter IOLs. Since blue light filter IOLs did not show any functional disadvantage, but potentially protect the macula from AMD, blue light filter IOLs may be considered as a reasonable alternative to traditional IOLs, especially in eyes with a high risk for the development of macular degeneration.

Lamellar corneal dissection for visualization of the anterior chamber before triple procedure.

PURPOSE: Open-sky cataract extraction during triple procedure can be associated with higher risk of complications owing to the missing counterbalance by the cornea. Herein, we present a fast and easy technique for visualization of the anterior chamber and the lens in eyes with opaque corneas planed for triple procedure. MATERIALS AND METHODS: Four patients with corneal oedema due to Fuchs' endothelial dystrophy and cataract underwent triple procedure. As the anterior chamber view was limited, the central 7.0 mm of the cornea was marked. Then, 60-80% of the corneal thickness was removed by lamellar dissection and filled with hydroxypropylmethylcellulose. Continuous curvilinear capsulorhexis (CCC) and phacoemulsification with intraocular lens implantation through a corneoscleral tunnel were then performed and at the end the remaining corneal tissue was excised and the donor tissue fixed with a single running continuous suture. RESULTS: Lamellar corneal dissection enhances the anterior chamber view and CCC can be performed under stable anterior chamber condition. Phacoemulsification via sclerocorneal tunnel could be easily performed under good anterior chamber view in all cases. The operation time was 60-75 min in all cases. CONCLUSION: Lamellar corneal dissection in opaque corneas before cataract extraction is a useful technique for enhancing anterior chamber view in cases of triple procedure.

Role of factor V Leiden and prothrombin 20210A in patients with retinal artery occlusion.

PURPOSE: Retinal artery occlusion is a common vision-threatening disease. Among other risk factors, coagulopathies leading to a hypercoagulable state have been associated with retinal artery occlusion. Numerous studies have shown that two genetic variants, factor V Leiden and prothrombin 20210A, cause a procoagulant state. However, their role in the pathogenesis of retinal artery occlusion is still unclear. The purpose of the present study was therefore to investigate a possible association between factor V Leiden, prothrombin 20210A, and retinal artery occlusion. METHODS: In the present retrospective case-control study, we studied 136 patients with retinal artery occlusion and 136 age- and gender-matched control subjects. The presence of factor V Leiden and prothrombin 20210A alleles was determined by polymerase chain reaction. RESULTS: The prevalence of heterozygosity for the prothrombin G20210A variant did not significantly differ between patients and controls (three patients vs two controls, P=0.65). Distribution of factor V Leiden genotypes revealed no significant difference among the two groups (heterozygosity: eight patients vs 11 controls, P=0.47). As for other risk factors, arterial hypertension, a history of stroke and myocardial infarction were significantly more frequent in patients than in controls. CONCLUSION: Our data suggest that factor V Leiden and prothrombin 20210A do not play a major role in patients with retinal artery occlusion.

[Octreotide scintigraphy for the diagnosis of active Graves' ophthalmopathy]. / Oktreotidszintigraphie zur Diagnose der aktiven endokrinen Orbitopathie.

PURPOSE: In this study the diagnostic accuracy of orbital octreotide uptake in patients with presumed active Grave's ophthalmopathy (GO) was evaluated. PATIENTS AND METHODS: A prospective study of 23 patients suffering from GO was carried out. Single photon emission computed tomography (SPECT) images were obtained 4 h after iv injection of 3 mCi 111 indium octreotide. The results were correlated with the patients clinical state during a follow-up of 17.5+/-6 months. RESULTS: Octreotide scintigraphy was positive in 15 and negative in 8 cases, 12 patients with positive octreotide scintigraphy underwent immunosuppressive treatment and showed a clinically positive response with regression of symptoms. In three cases the patients refused immunosuppressive treatment. Patients with negative pathologic orbital octreotide uptake did not undergo any treatment. CONCLUSION: Octreotide scintigraphy is a useful tool to determine the activity state of Graves' ophthalmopathy. Since Graves' ophthalmopathy must be treated in the active phase, octreotide scintigraphy should be performed in subacute cases to facilitate the indications for immunosuppressive treatment.

The 3'-Terminal nucleotide sequence of encephalomyocarditis virus RNA.

Poly(A)-containing encephalomyocarditis virus RNA functions as an excellent template for cDNA synthesis in vitro with an RNA-dependent DNA polymerase in the presence of an oligothymidylate primer. Under appropriate conditions, discrete transcripts of increasing chain length were obtained, suitable for sequence analysis. A limited cDNA fragment of 36 nucleotides, primer (dT)10 included, was synthesized when dGTP was omitted from the reaction mixture and its primary structure was elucidated using direct DNA-sequencing methods. The complement corresponds to the 3' end of encephalomyocarditis RNA. The hexanucleotide (5'-3')(A-A-U-A-A-A) found in this sequence is also present in all 3' non-coding regions of poly(A)-containing eukaryotic mRNAs studied until now, in nearly identical positions relative to the poly(A) tail. The possible biological significance of this structural homology is discussed.

Influenza virus messenger RNAs are incomplete transcripts of the genome RNAs.

The results of ribonuclease T1 oligonucleotide fingerprint analyses indicate that influenza virus messenger RNAs are incomplete transcripts of the corresponding genome RNAs and that in this respect they differ from the unpolyadenylated virus specific complementary RNAs obtained from infected cells. From the position of the untranscribed oligonucleotide in the virus RNA sequence and the ability or inability of the different transcripts to protect the 5' terminal nucleotide of virus RNAs against nuclease S1 digestion, it is concluded that whereas the unpolyadenylated cRNAs are complete transcripts, the polyadenylated messenger RNAs lack sequences complementary to the 5' end of the genome molecules.

Absence of 5' terminal capping in encephalomyocarditis virus RNA.

The nature of the 5' terminus of encephalomyocarditis (EMC) virion RNA has been investigated. We have failed to detect any capped products or nucleoside polyphosphates arising upon complete digestion of the RNA with T1, T2, and pancreatic ribonucleases, and it would therefore appear that the 5' terminus of EMC virus RNA is not phosphorylated and not capped with m7G. EMC virions do contain, however, large amounts of all four 5'-monosubstituted nucleoside triphosphates (4.2M pppG; 16.4M pppA; 3.OM pppU and 2.5M pppC), of which at least a proportion (about 15-20%) appear to remain bound to fully denatured RNA in the presence of divalent cations.

Influenza virus genome consists of eight distinct RNA species.

The genomic RNA of the avian influenza A virus, fowl plague, was fractionated into eight species by electrophoresis in polyacrylamide-agarose gels containing 6 M urea. The separated 32P-labeled RNA species were characterized by digestion with RNase T1 and fractionation of the resulting oligonucleotides by two-dimensional gel electrophoresis; this demonstrated that each species has a distinct nucleotide sequence. A tentative correlation of each genome RNA species with the virus protein that it encodes was made.

The determination of secondary structure in the poly(C) tract of encephalomyocarditis virus RNA with sodium bisulphite.

The degree of secondary structure in the poly(C) tract of encephalomyocarditis virus (EMCV) RNA has been investigated using sodium bisulphite, which brings about the hydrolysis of non-base-paired cytidylic acid to uridylic acid in RNA. The percentage conversion of C to U in the poly(C) region of native EMCV RNA was similar to that found in a synthetic polynucleotide lacking secondary structure [poly(C)]. When poly(I) was annealed to either native or denatured EMCV RNA, it protected the poly(C) tract from the action of bisulphite. It is concluded that the poly(C) tract of EMCV RNA in solution is very largely single-stranded.

Primary sequence of the 16S ribosomal RNA of Escherichia coli.

Recent progress in the nucleotide sequence analysis of the 16S ribosomal RNA from E. coli is described. The sequence which has been partially or completely determined so far encompasses 1520 nucleotides, i.e. about 95% of the molecule. Possible features of the secondary structure are suggested on the basis of the nucleotide sequence and data on sequence heterogeneities, repetitions and the location of modified nucleotides are presented. In the accompanying paper, the use of the nucleotide sequence data in studies of the ribosomal protein binding sites is described.

Location and characteristics of ribosomal protein binding sites in the 16S RNA of Escherichia coli.

Specific binding sites for five proteins of the Escherichia coli 30S ribosomal subunit have been located within the 16S RNA. The sites are structurally diverse and range in size from 40 to 500 nucleotides; their functional integrity appears to depend upon both the secondary structure and conformation of the RNA molecule. Evidence is presented which indicates that additional proteins interact with the RNA at later stages of subunit assembly.

An investigation of the 16-S RNA binding sites of ribosomal proteins S4, S8, S15, and S20 FROM Escherichia coli.

The RNA binding sites of four 30-S ribosomal subunit proteins from Escherichia coli, namely S4, S8, S15, and S20 were prepared from reconstituted single protein - 16-S-RNA complexes by mild enzymic digestion of non-protected RNA regions. Oligonucleotide fingerprints of the protected RNA regions were obtained and their positions were located within the 16-S-RNA sequence. They were not completely contiguous regions of RNA; oligonucleotides had been excised from each of them. The binding sites of S4 and S20, and those of S8 and S15 showed overlapping. The specificity of the RNA binding sites was confirmed by a reconstitution method.

The determination of the primary structure of the 16S ribosomal RNA of Escherichia coli. III. Further studies.

In this paper, we describe in detail the recent progress in the nucleotide sequence analysis of the 16S ribosomal RNA from E. coli. The sequence which has been partially or completely determined so far encompasses 1520 nucleotides, i.e. about 95 percent of the molecule. Possible features of the secondary structure are suggested on the basis of the nucleotide sequence and data on sequence heterogeneities, repetitions and the location of modified nucleotides are presented.

Nucleotide sequences of the T1 and pancreatic ribonuclease digestion products from some large fragments of the 23S RNA of Escherichia coli.

When the 23S RNA from E. Coli was pretreated for 1 h at 60 degrees in the presence of Mg++ and K+ and then subjected to T1 ribonuclease attack, resistant fragments were recovered from 3 regions of the molecule: region A (containing 470-500 nucleotides) located at the 5' end of 23S RNA, region B (containing 520-550 nucleotides) located at the 3' end and region C (containing 110-120 nucleotides) lying between region A and region B. The nucleotide sequences of the T1 and pancreatic ribonuclease digestion products from these 3 regions have been studied and in most cases determined. In the course of these studies, a certain number of abnormal nucleotides, which are not methylated, have been encountered. A low level of sequence heterogeneity was detected.

Comparative study of the 16S RNA's of Escherichia coli and Proteus vulgaris.

We have studied the primary structure of 16S ribosomal RNA from Proteus vulgaris. The oligonucleotides containing methylated bases appeared to be the same as those of Escherichia coli, with one exception. We have also studied the base composition of the oligonucleotides obtained after T1 ribonuclease digestion of 16S RNA. On the basis both of their position on the fingerprint and of their pancreatic ribonuclease analyses, approximately 25 appeared to differ from those found in the E. coli T1 fingerprints. From the isolation of large fragments arising from the action of endogeneous endonucleases, we have concluded that the RNA sequences of both species are very similar. We have shown that the 5' and 3' extremities of 16S RNA are mostly conserved. It appears that the regions which are known to interact with ribosomal proteins in E. coli (particularly S8 and S15) are also less modified. It is noteworthy that the sequence modifications which have been observed are clustered and often correspond to regions of heterogeneity in E. coli 16S RNA.