Retropupillary iris claw intraocular lens for aphakia.

BACKGROUND: To assess outcomes of the iris claw intraocular lens implanted in the retropupillary position for correction of aphakia without adequate capsular support. DESIGN: Retrospective study of patients consulted at two private practices and a tertiary public hospital clinic in Brisbane, Queensland. SAMPLES: Thirty-two consecutive patients who underwent posterior chamber insertion of the iris claw intraocular lens alone or in combination with other procedure/s by the same consultant ophthalmologist (GL). METHODS: Lens power was calculated using an A-constant of 117.0. MAIN OUTCOME MEASURES: Clinical examination. RESULTS: Thirty-four eyes in 32 patients (23 male, 9 female) were included in the study. Indications for surgery were pseudophakic bullous keratopathy (n = 14), aphakia from previous lens extraction/lensectomy (n = 9), subluxation of intraocular lens (n = 7), cataract extraction (n = 2), explantation of anterior chamber intraocular lens due to uveitis (n = 1) and for Baerveldt tube insertion (n = 1). Follow-up duration ranged from 1 to 68 months. Of the 26 eyes followed for at least 6 months, the final vision improved in 69% (n = 18), remained unchanged in 8% (n = 2) and worsened in 23% (n = 6). Final visual acuity was 6/12 or better in 58% (n = 15). Complications included iris trauma/defect (n = 8), pupil irregularity/ovalization (n = 6), microhyphaema (n = 2) and lens decentration (n = 2). CONCLUSION: Implantation of the iris claw intraocular lens in the retropupillary position is a useful technique for correction of aphakic eyes with sufficient iris support, avoiding the corneal complications of an anterior chamber intraocular lens and the surgical challenge of a sutured posterior chamber intraocular lens.

Phosphorylation of myosin light chain during capping of mouse T-lymphoma cells.

Colchicine induces the clustering of at least three different T-lymphoma surface antigens (T200, Thy-1, and gp 69/71) into a cap structure in the absence of any external ligand. In addition, colchicine induces the intracellular accumulation of actin and myosin directly beneath the surface cap structure. We have discovered that myosin molecules (both heavy and light chains) are closely associated with the plasma membrane of T-lymphoma cells. Most importantly, we have found that the 20,000-dalton light chain of lymphocyte myosin is both phosphorylated and preferentially accumulated in the plasma membrane of colchicine-induced capped cells. It is proposed that myosin light chain is directly involved in the activation of membrane-associated actomyosin required for the collection of surface proteins into a cap structure (analogous to muscle cell sliding filament contraction).

Impact of simulated visual impairment on the cognitive test performance of young adults.

AIMS: This study investigated the effect of simulated visual impairment on the speed and accuracy of performance on a series of commonly used cognitive tests. METHODS: Cognitive performance was assessed for 30 young, visually normal subjects (M = 22.0 +/- 3.1 years) using the Digit Symbol Substitution Test (DSST), Trail Making Test (TMT) A and B and the Stroop Colour Word Test under three visual conditions: normal vision and two levels of visually degrading filters (Vistech) administered in a random order. Distance visual acuity and contrast sensitivity were also assessed for each filter condition. RESULTS: The visual filters, which degraded contrast sensitivity to a greater extent than visual acuity, significantly increased the time to complete (p <.05), but not the number of errors made, on the DSST and the TMT A and B and affected only some components of the Stroop test. CONCLUSIONS: Reduced contrast sensitivity had a marked effect on the speed but not the accuracy of performance on commonly used cognitive tests, even in young individuals; the implications of these findings are discussed.

The participation of adenylate cyclase in lymphocyte capping.

In this study, we have observed that cells increase their intracellular cAMP to relatively high levels during receptor capping induced by either ligand-dependent (anti-Thy-1 antibody) or ligand-independent (colchicine) treatment. In addition, we have found that under capping conditions, membrane-bound adenylate cyclase is induced to co-cap with independent membrane molecules such as Thy-1 antigens. These findings suggest that the binding of anti-Thy-1 to its receptors or treatment with colchicine induces the molecular reorganization of membrane-bound adenylate cyclase which may be responsible for activating the contractile machinery required for the collection of surface receptors into a cap structure.

Anti-VEGF treatment for subfoveal idiopathic (type II) choroidal neovascular membranes.

Two cases of subfoveal choroidal neovascular membranes (CNVM) in the absence of other pathology are described in two young patients who were successfully treated with anti-vascular endothelial growth factor (anti-VEGF) agents. The natural history of idiopathic CNVM and factors influencing the decision to treat using various options are discussed. Current experience with use of anti-VEGF is also outlined. Lastly, the importance of timely referral for thorough investigations to exclude underlying aetiology and consideration for treatment is highlighted.

In search of optimal productivity and hospital size: a case study.

This study examines the relationship between optimal employee productivity and hospital size based on a sample from the state of Texas during 1982-91. Full-time equivalents (FTEs) per adjusted occupied bed is employed to represent productivity. The number of beds, total employees, and eight standard categories are used to measure hospital size. The impact of the diagnosis-related group implementation on productivity is also tested. Major findings suggest that productivity is found to be the highest for hospitals with 272 beds or 945 employees or in the category IV or V. The implementation of the DRG has not increased employee productivity.

DPX-3778 promotes proliferation of tobacco callus in vitro.

DPX-3778, the triethanolamine salt of 3-(p-chlorophenyl)-6-methoxy-s-triazine-2,4(1H,3H) dione, at concentrations of 0.124-2.48 µM enhanced ca. 4-5-fold the proliferation of tobacco (Nicotiana tabacum L. cv. Wisconsin 38) callus cultured in the presence of indole-3-acetic acid and kinetin, and retarded its senescence.

Plant regeneration through somatic embryogenesis in root-derived callus of ginseng (Panax ginseng C. A. Meyer).

Callus culture was initiated from expiants of mature root tissues of ginseng (Panax ginseng C.A. Meyer) on MS medium enriched with 2,4-D. The ageing callus produced numerous embryoids in this medium. Reculture of these embryoids in media (1/2 MS or B5) supplemented with benzyladenine and gibberellic acid resulted in profuse plantlet regeneration.

Requirement for nuclear factor-kappaB activation by a distinct subset of CD40-mediated effector functions in B lymphocytes.

CD40 stimulation, which is crucial for generating an effective T-dependent humoral response, leads to the activation of transcription factors NF-AT (nuclear factor of activated T cells), AP-1 (activator protein-1), and NF-kappaB (nuclear factor-kappaB). However, which CD40-mediated B cell functions actually require activation of specific transcription factors is unknown. We examined the causal relationship between NF-kappaB activation and CD40 effector functions by evaluating CD40 functions in the presence of an inducible mutant inhibitory kappaBalpha (IkappaBalpha) superrepressor. IkappaBalphaAA inhibited nuclear translocation of multiple NF-kappaB dimers without the complicating effect of depriving cells of NF-kappaB during development. This approach complements studies that use mice genetically deficient in single or multiple NF-kappaB subunits. Interestingly, only a subset of CD40 effector functions was found to require NF-kappaB activation. Both CD40-induced Ab secretion and B7-1 up-regulation were completely abrogated by expression of IkappaBalphaAA. Surprisingly, up-regulation of Fas, CD23, and ICAM-1 was partially independent, and up-regulation of LFA-1 was completely independent, of CD40-induced NF-kappaB activation. For the first time, it is clear that distinct transcription factors are required for the dynamic regulation of CD40 functions.

Characterization of CD40 signaling determinants regulating nuclear factor-kappa B activation in B lymphocytes.

CD40 signaling to B cells is important for generating an effective humoral immune response. CD40 ligation leads to B cell activation events such as proliferation, Ig secretion, isotype switching, and up-regulation of cell surface molecules, as well as the generation of memory B cells. Many of these events are dependent upon the ability of CD40 to activate the transcription factor NF-kappa B (NF-kappa B). To define the CD40 signaling components upstream of NF-kappa B activation and the functional consequences downstream of NF-kappa B activation, we examined mouse B cell transfectants expressing wild-type or mutant human CD40. Analysis of CD40 cytoplasmic domain truncation and point mutants defined a 10-amino acid CD40 cytoplasmic signaling determinant required for NF-kappa B activation. A threonine residue at position 234, previously shown to be important for CD40 association with TNF receptor-associated factor 2 (TRAF2), TRAF3, and TRAF5, was not required for NF-kappa B activation. This suggests that in B cells, CD40-induced NF-kappa B activation can occur independently of TRAF2 and TRAF5 association. NF-kappa B activation was independent of the transmembrane domain of CD40, suggesting that it is independent of p23, a molecule that associates with CD40 in a region other than the cytoplasmic domain. Proteasome-dependent inhibitory kappa B alpha (I kappa B alpha) and I kappa B beta degradation occurred downstream of CD40 ligation and preceded CD40-mediated NF-kappa B nuclear translocation. CD40- or pervanadate-mediated I kappa B tyrosine phosphorylation was not detected. NF-kappa B activation correlated with the ability of CD40 to induce Ab secretion and the up-regulation of ICAM-1 and LFA-1. However, NF-kappa B activation was insufficient for CD40-mediated up-regulation of B7-1, Fas, and CD23.

Different CD40-mediated signaling events require distinct CD40 structural features.

Signals delivered to B cells through CD40 are critical to the development of humoral immune responses. In this study we characterize regions of the 62-amino acid cytoplasmic domain of human CD40 (hCD40) that are essential for signal transduction and examine the functional consequences of mutations in these regions. A panel of mutant hCD40 molecules was stably expressed in mouse B cell lines and tested for its ability to stimulate Ab secretion, homotypic adhesion, and increased surface expression of B7, Fas, CD23, LFA-1, and intracellular adhesion molecule-1. Our results indicate that CD40 contains at least two major signaling determinants in the cytoplasmic domain: one disrupted by a truncation of 22 amino acids, and a second disrupted by the removal of 10 additional amino acids. The second determinant includes threonine 234, a residue previously shown to be important in CD40 signal transduction. Our functional analysis of alanine and serine substitutions at position 234 indicates that phosphorylation of this residue may be important for full CD40 signaling activity.

Molecular mechanisms of B lymphocyte activation by the immune response modifier R-848.

The imidazoquinoline R-848, originally identified as a highly effective antiviral agent, has recently been shown to be capable of potent B lymphocyte activation. The B cell-activating properties of R-848 are strikingly similar to the effects of the CD40 ligand CD154. The present study demonstrates that this similarity extends to the intracellular signaling pathways triggered by the compound, although both overlapping and distinct mechanisms of signaling were seen. Like CD40 ligation, R-848 stimulated activation of the stress-activated protein kinases c-Jun kinase and p38 and activated the NF-kappaB family of transcription factors. Both R-848- and CD40-mediated B cell differentiation were dependent upon NF-kappaB activation, although the relative importance of individual NF-kappaB family members appeared to differ between R-848- and CD40-mediated signals. Both signals were partially dependent upon induction of TNF-alpha and IL-6, and the cytoplasmic adaptor molecule TNF receptor-associated factor 2 is involved in both R-848- and CD40-mediated differentiation.

Unusual sequences of group 3 LEA mRNA inducible by maturation or drying in soybean seeds.

Two cDNA clones, pGmPM8 and pGmPM10, which correspond to two mRNA species in mature or dry soybean seeds, were characterized. The deduced proteins, based on DNA sequence analysis, have a molecular mass of 49 and 51 kDa for pGmPM8 and pGmPM10, respectively. These two cDNA clones share a high homology with an amino acid identity of about 90% between the two deduced proteins. Both proteins appear to be extremely hydrophilic except at their N-termini that contain a 29 amino acid hydrophobic region at the N-terminus and the sizes of proteins decrease after co-incubating with ER membranes. These two proteins contain more than 30 similar, contiguous repeats of 11 amino acids, which is characteristic of group 3 LEA proteins. The mRNAs corresponding to pGmPM8 and pGmPM10 were expressed at high levels in dried or mature soybean seeds, but not in fresh immature seeds. The RNAs were also present in abscisic acid (ABA) treated leaves or cultured cells, and in tissues subjected to water stress or low temperatures.

Tissue- and stage-specific expression of a soybean (Glycine max L.) seed-maturation, biotinylated protein.

A cDNA clone GmPM4 which encodes mRNA species in mature or dry soybean seeds was characterized. DNA sequence analysis shows that the deduced polypeptides have a molecular mass of 68 kDa. GmPM4 proteins have a relatively high amino acid sequence homology with a major biotinylated protein isolated from pea seeds, SBP65, but both of these proteins differ markedly from that of presently known biotin enzymes. The accumulation of GmPM4 mRNA is detectable in the leaf primodium and the vascular tissues of the hypocotyl-radicle axis of mature seeds, and the GmPM4 proteins are present at high levels in dry and mature soybean seeds, but not in fresh immature seeds. It degrades rapidly at the early stage of seed germination. These proteins are boiling-soluble and biotinylated when they are present endogenously in soybean seeds; however, the same recombinant protein expressed in Escherichia coli is boiling-soluble, but it is not biotinylated.