Effect of heparin surface modification of polymethylmethacrylate intraocular lenses on signs of postoperative inflammation after extracapsular cataract extraction. One-year results of a double-masked multicenter study

PURPOSE

A heparin surface modified posterior chamber intraocular lens (IOL) was compared with a conventional polymethylmethacrylate (PMMA) IOL regarding postoperative complications caused by inflammation.

METHODS

Five hundred twenty-four patients from 10 different centers were included in a parallel group, double-masked, multicenter study.

RESULTS

The cumulative number of patients with inflammatory cellular deposits on their IOLs during the first postoperative year differed significantly in favor of the heparin surface modified group, with 29.8% of the patients having cellular deposits compared with 48.8% of patients in the control group. Cellular deposits were observed most frequently at 3 months after surgery, and the difference between the groups was most pronounced and statistically significant at this time. The same results were seen at 1 year, but the difference was not significant. The number of cellular deposits per patient, however, was significantly lower in the heparin surface modified group at 1 year. Cumulatively, there were significantly more patients with posterior synechiae in the PMMA group than in the heparin surface modified group during the 1-year follow-up. Complications were few and comparable between the groups.

CONCLUSION

The results of this study indicate that heparin surface modification reduces the inflammatory response to PMMA IOLs.

Reversible hyperphosphorylation and reorganization of vimentin intermediate filaments by okadaic acid in 9L rat brain tumor cells

Okadaic acid (OA), a protein phosphatase inhibitor, was found to induce hyperphosphorylation and reorganization of vimentin intermediate filaments in 9L rat brain tumor cells. The process was dose dependent. Vimentin phosphorylation was initially enhanced by 400 nM OA in 30 min and reached maximal level (about 26-fold) when cells were treated with 400 nM OA for 90 min. Upon removal of OA, dephosphorylation of the hyperphosphorylated vimentin was observed and the levels of phosphorylation returned to that of the controls after the cells recovered under normal growing conditions for 11 h. The phosphorylation and dephosphorylation of vimentin induced by OA concomitantly resulted in reversible reorganization of vimentin filaments and alteration of cell morphology. Cells rounded up as they were entering mitosis in the presence of OA and returned to normal appearance after 11 h of recovery. Immuno-staining with anti-vimentin antibody revealed that vimentin filaments were disassembled and clustered around the nucleus when the cells were treated with OA but subsequently returned to the filamentous states when OA was removed. Two-dimensional electrophoresis analysis further revealed that hyperphosphorylation of vimentin generated at least seven isoforms having different isoelectric points. Furthermore, the enhanced vimentin phosphorylation was accompanied by changes in the detergent-solubility of the protein. In untreated cells, the detergent-soluble and -insoluble vimentins were of equal amounts but the solubility could be increased when vimentins were hyperphosphorylated in the presence of OA. Taken together, the results indicated that OA could be involved in reversible hyperphosphorylation and reorganization of vimentin intermediate filaments, which may play an important role in the structure-function regulation of cytoskeleton in the cell.

A maize cryptic Ac-homologous sequence derived from an Activator transposable element does not transpose

Sequences sharing homology to the transposable element Activator (Ac) are prevalent in the maize genome. A cryptic Ac-like DNA, cAc-11, was isolated from the maize inbred line 4Co63 and sequenced. Cryptic Ac-11 has over 90% homology to known Ac sequences and contains an 11 bp inverted terminal repeat flanked by an 8 bp target site duplication, which are characteristics of Ac and Dissociation (Ds) transposable elements. Unlike the active Ac element, which encodes a transposase, the corresponding sequence in cAc-11 has no significant open reading frame. A 44 bp tandem repeat was found at one end of cAc-11, which might be a result of aberrant transposition. The sequence data suggest that cAc-11 may represent a remnant of an Ac or a Ds element. Sequences homologous to cAc-11 can be detected in many maize inbred lines. In contrast to canonical Ac elements, cAc-11 DNA in the maize genome is hypermethylated and does not transpose even in the presence of an active Ac element.

Restriction endonuclease analysis of chloroplast DNA from streptomycin-resistant mutants of Nicotiana plumbaginifolia

Chloroplast DNA isolated from wild-type Nicotiana plumbaginifolia and 12 maternally inherited streptomycin-resistant mutants was digested with various restriction enzymes and the resultant patterns were compared. No gross structural alterations of the chloroplast genome were detected in any mutants; however, variant patterns owing to the gain or loss of a restriction site were found in three mutants, SR1007, SR1019, and SR1022. The variant patterns in SR1019 and SR1022 are identical and are the results of mutation in the psbG gene coding for a chloroplast membrane protein G, and that in SR1007 is due to mutation in the 16S rRNA gene. Inheritance of the variant patterns in mutants SR1007 and SR1019 was studied. The results showed that the variant patterns and streptomycin resistance were co-transmitted in reciprocal crosses.

Physical maps of Nicotiana chloroplast DNA constructed by an efficient procedure

The restriction profiles of chloroplast DNA (cpDNA) from Nicotiana tabacum, N. sylvestris, N. plumbaginifolia, and N. otophora were obtained with respect to AvaI, BamHI, BglI, HindIII, PstI, PvuII, SalI, and XhoI. An efficient mapping method for the construction of cpDNA physical maps in Nicotiana was established via a computer-aided analysis of the complete cpDNA sequence of N. tabacum for probe selection. The efficiency of this approach is demonstrated by the determination of cpDNA maps from N. sylvestris, N. plumbaginifolia, and N. otophora with respect to all of the above restriction endonucleases. The size and basic structure of the cpDNA from the three species are almost identical, with an addition of approximately 80 bp in N. plumbaginifolia. The restriction patterns and hence the physical maps between N. tabacum and N. sylvestris cpDNA are identical and there is no difference in the Pvull digests of cpDNA from all four species. Restriction site variations in cpDNA from different species probably result from point mutations, which create or eliminate a particular cutting site, and they were observed spanning the whole chloroplast molecule but highly concentrated in both ends of the large, single-copy region. The results presented here will be used for the forthcoming characterization of chloroplast genomes in the interspecies somatic hybrids of Nicotiana, and will be of great value in completing the exploration of the phylogenetic relationships within this already extensively studied genus.

Induction of heat-shock response and alterations of protein phosphorylation by a novel topoisomerase II inhibitor, withangulatin A, in 9L rat brain tumor cells

Withangulatin A is a newly identified in vitro topoisomerase II inhibitor isolated from the Chinese antitumor herb Physalis angulata. In vivo, it was found to be cytotoxic, capable of suppressing general protein synthesis and of inducing the synthesis of a small set of proteins including those generated by heat-shock treatment. The 70 kDa protein generated by withangulatin A was unequivocally identified as the heat-shock protein 70 (HSP70) since both proteins migrated to the same position on two-dimensional polyacrylamide gels, could be recognized by a monoclonal antibody to human HSP70, and exhibited identical peptide maps. The induction of protein synthesis by withangulatin A was regulated at the transcriptional level since it was aborted in cells pre-treated with actinomycin D. However, the initiation of this process did not require de novo protein synthesis since it was not affected by cycloheximide. Other cellular effect of withangulatin A was alterations of protein phosphorylation including an enhancement of phosphorylation of a 65 kDa protein which was also detected in the heat-shocked cells. Moreover, this process was observed within 7.5 min after the initial heat treatment which is much faster than the onset of HSP synthesis. Therefore, increased phosphorylation of the 65 kDa protein may represent one of the earliest signals generated by both heat-shock and withangluatin A and may be involved in the upstream regulation of heat-shock response in cells.

Oleosin isoforms of high and low molecular weights are present in the oil bodies of diverse seed species

Oleosins are unique and major proteins localized on the surface of oil bodies in diverse seed species. We purified five different oleosins (maize [Zea mays L.] KD 16 and KD 18, soybean [Glycine max L.] KD 18 and KD 24, and rapeseed [Brassica campestris L.] KD 20), and raised chicken antibodies against them. These antibodies were used to test for immunological cross-reactivity among oleosins from diverse seed species. Within the same seed species, antibodies raised against one oleosin isoform did not cross-react with the other oleosin isoform (i.e. between maize oleosins KD 16 and KD 18, and between soybean oleosins KD 18 and KD 24). However, the respective antibodies were able to recognize oleosins from other seed species. Where interspecies cross-reactivity occurred, the results suggest that there are at least two immunologically distinct isoforms of oleosins present in diverse seed species, one of lower M(r), and another one of higher M(r). This suggestion is also supported by the relative similarities between the amino acid sequence of a small portion of rapeseed oleosin KD 20 and those of maize oleosins KD 16 and KD 18. In maize kernel, there was a tissue-specific differential presentation of the three oleosins, KD 16, KD 18, and KD 19, in the oil-storing scutellum, embryonic axis, and aleurone layer. The phylogenetic relationship between the high and low M(r) isoforms within the same, and among diverse, seed species is discussed.

Treatment of macular hole retinal detachment

Seven patients with macular hole retinal detachment were treated by intravitreal gas injection with or without release of subretinal fluid. Macular buckling, diathermy, cryopexy, or vitrectomy were not used. The patients were placed prone for eight hours a day until the gas had absorbed. In five of the seven patients the retina became reattached within three days and remained reattached with follow-up periods of three to 22 months (average nine months). It is believed that such detachments are due to vitreoretinal traction and the intravitreal gas bubble relieves this traction. This technique is simple, safe, and does not require costly or sophisticated instruments. It has an added advantage in preserving macular function.

Isolation and characterization of streptomycin-resistant mutants in Nicotiana plumbaginifolia

Streptomycin-resistant colonies were isolated from protoplast cultures of haploid Nicotiana plumbaginifolia based on their ability to green in medium containing 1 mg/ml streptomycin sulfate. The frequency of resistant colonies was 0.9×10(-5) in nonmutagenized culture, and increased ten-fold following treatment of culture with 10 μg/ml N-methyl-N'-nitro-N-nitrosoguanidine. Of a total of 52 resistant clones isolated, 2 gave rise to haploid, 15 to diploid, and 3 to tetraploid plants upon transfer of calli to differentiation medium. Leaf-segment and protoplast assays showed that all diploid regenerates were resistant to streptomycin but sensitive to chloramphenicol, kanamycin, lincomycin, neomycin, and spectinomycin. Plants in most diploid clones were fertile and able to set seeds when self-fertilized and crossed reciprocally to wild-type plants. Inheritance of streptomycin resistance was studied in the diploid clones and, without exception, the resistance was transmitted maternally. Comparative studies of the ultrastructure of organelles and protein synthesis in isolated chloroplasts between wild-type and resistant clones in the presence of streptomycin suggest that streptomycin resistance is controlled by chloroplasts.

Adverse effect of intraoperative phenylephrine 10%: case report

The case is reported of a patient who suffered severe acute hypertension, cardiac arrhythmia, and myocardial infarction probably as a direct effect of phenylephrine overdose. Instillation of the drops during surgery probably enhanced the systemic absorption of a significant amount of the drug. Therefore it should be used during surgery with caution, especially in elderly patients and those with cardiovascular disease.

Purification and molecular properties of malate dehydrogenase from the marine diatom Nitzschia alba

Malate dehydrogenase (EC 1.1.1.37) was purified to homogeneity from the marine diatom Nitzschia alba. The purification steps consisted of (NH4)2SO4 precipitation, ion-exchange chromatography, Blue Sepharose affinity chromatography and gel filtration. A typical procedure provided 685-fold purification with 58% yield. The Mr of the holoenzyme was estimated to be 322,000 by gel filtration and 316,000 by ultracentrifugation. The enzyme migrated as a single polypeptide spot on two-dimensional polyacrylamide-gel electrophoresis with an Mr of 38,500, suggesting that the holoenzyme consists of eight identical subunits. This is the first case where malate dehydrogenase has been shown to be a homo-octamer; malate dehydrogenases from other sources are predominantly homodimers, with two homotetramers reported so far. The amino acid composition of the enzyme was determined and the N-terminal sequence of the subunit polypeptide was found to be Arg-Lys-Val-Ala-Val-Met-Gly-Ala-Ala-Gly-Gly-Ile-Gly-Gln-Pro-Leu-Ser-Leu- Leu-Leu - Lys-Leu-Ser-Pro-Gln-Val-Thr-Glu-Leu-Ser-Lys-Tyr-. For the first 21 amino acid residues, near-identical sequences were reported for the enzymes isolated from pig heart, Escherichia coli, yeast and watermelon. Other physicochemical and catalytic properties, such as sedimentation coefficient, partial specific volume, Stokes radius, excitation and emission maxima, Michaelis constants, pH optima, pH stability range and activation energy, of this enzyme are also presented.

Cardiac hypertrophy cannot proceed without initial suppression of protein synthesis

Stress was induced in rat hearts by heat shock and aortic banding and in cardiac cell cultures by heat shock. Proteins were labeled with [35S]-methionine, resolved by electrophoresis, and isotope incorporation measured. Determinations were made during and following stress. The immediate response was stress protein (SP) synthesis, cessation of normally occurring protein synthesis and reduced isotope incorporation. Following recovery, the prestress protein pattern returned, SP synthesis remained high and label incorporation doubled. Response of hearts to the two stresses were similar. Initial suppression may be an important precursor to accelerated protein synthesis seen in hypertrophy.

Heat shock stress initiates simultaneous transcriptional and translational changes in the dog heart

The acute response to heat shock was examined in the intact canine heart. Ventricular samples were removed before the dogs were heated. After heat treatment, the hearts were removed. Total RNA was extracted from pre and post heat shocked samples, translated in vitro with [35S]methionine and visualized by autoradiography. Polysome profiles from pre and post heat shocked hearts were then analyzed. Heat shocked hearts synthesized mRNAs for 71 kD stress proteins. The polysome profile after heat treatment showed a steady decline of the polysomal material toward the heavier polysome region when compared to myocardium before heat treatment. Stress protein synthesis and polysomal disaggregation are initial responses to stress that, in the mammalian heart, may be precursors to hypertrophy.

Preliminary characterization of molecules that increase cell free translational activity of cardiac cytoplasmic RNA

Previous evidence indicates that cells generate molecules that alter transcription in response to stress. Accordingly, we conducted preliminary experiments to characterize these molecules. Extracts were prepared from normal and experimental canine hearts in which a 100 mmHg gradient was created across the ascending aorta for 6 h. Experimental extracts were then treated by ultrafiltration through YM 10 and YM 30 membranes, by incubation with immobilized trypsin for 1 h at 37 degrees C and by incubation in a boiling water bath for 10 min. Extracts were perfused through isolated rat hearts for 1 h. Total cytoplasmic RNA was then extracted from the perfused heart and translated in a cell free medium containing [35S]-methionine. Incorporated label into newly synthesized protein was determined by liquid scintillation counting. A 13% mean increase in translational activity was produced by the fraction of the experimental extract passing through the YM 10 membrane compared with the material retained by YM 10 and YM 30 membranes. A 14% mean decrease in translational activity was observed in hearts perfused with experimental extracts treated with immobilized trypsin compared to untreated experimental extracts. There was no significant difference in translational activity of hearts perfused with experimental extracts subjected to boiling compared with non-boiled experimental extracts. These data suggest that the active molecules may be heat stable peptides or peptide containing substances of 10000 daltons or less in molecular weight.

Diverse forms of stress lead to new patterns of gene expression through a common and essential metabolic pathway

Many eukaryotic organisms respond to heat shock by synthesizing new proteins. We examined the possibility that heat shock proteins represent a particular expression of a general response to stress and that, regardless of the nature of the effective stimulus, the same proteins are synthesized. Accordingly, cardiac stress was applied in the intact rat by four methods: banding the ascending aorta, increasing body temperature to 42 degrees C, reducing body temperature to 18 degrees C, and forcing the rat to swim until exhausted. The hearts were then extirpated and analyzed for new mRNA synthesis. The extracted RNA was translated in a cell-free medium containing [35S]methionine. Translation products were resolved by two-dimensional electrophoresis and visualized by autoradiography. Lactic acid concentration in heart tissue was determined enzymatically. The results showed that two new and distinct proteins of Mr 71,000 and isoelectric points of 5.8 and 6.1 were synthesized in hearts stressed by banding and by heating but not in hearts of exhausted swimmers or in animals at reduced body temperatures. There was no significant difference in cardiac lactic acid concentration between control hearts and hearts from swimmers or cold-treated animals. However, there was a 2-fold increase in lactic acid concentration in hearts of rats with banded aortas compared to controls and a 10-fold increase in heat shocked hearts. We conclude that, under conditions in which the energy requirements of the heart are not completely met by aerobic processes, the resultant lactic acidosis creates an intracellular environment that leads to the selective activation of genes, the production of new mRNA, and the synthesis of a typical group of stress proteins.

The molecules that initiate cardiac hypertrophy are not species-specific

Extracts from hypertrophying dog hearts perfused through isolated rat hearts increase the synthesis of messenger RNA and initiate hypertrophy in the treated hearts. Total RNA extracted from experimental and control hearts was translated in vitro and hybridized with polyuridylate. Synthesis of protein and polyadenylate-containing RNA was greater in rat hearts perfused with extracts of hypertrophying dog hearts than in control hearts. The results demonstrate that molecules from hypertrophying dog hearts are not species-specific since they are effective in stimulating transcription of messenger RNA in rat hearts as well as in dog hearts.