Zyklorotation des Auges bei wellenfrontgeführter LASIK mit statischem Iriserkennungstracker

PURPOSE

Centration of the ablation zone decisively influences the result of wavefront-guided LASIK. Cyclorotation of the eye occurs as the patient changes from the sitting position during aberrometry to the supine position during laser surgery and may lead to induction of lower and higher order aberrations.

METHODS

Twenty patients (40 eyes) underwent wavefront-guided LASIK (B&L 217z 100 excimer laser) with a static eyetracker driven by iris recognition (mean preoperative SE: -4.72+/-1.45 D; range: -1.63 to -7.00 D). The iris patterns of the patients' eyes were memorized during aberrometry and after flap creation.

RESULTS

The mean absolute value of the measured cyclorotation was -1.5+/-4.2 degrees (range: -11.0 to 6.9 degrees ). The mean cyclorotation was 3.5+/-2.7 masculine (range: 0.1 to 11.0 degrees ). In 65% of all eyes cyclorotation was >2 masculine.

CONCLUSIONS

A static eyetracker driven by iris recognition demonstrated that cyclorotation of up to 11 degrees may occur in myopic and myopic astigmatic eyes when changing from a sitting to a supine position. Use of static eyetrackers with iris recognition may provide a more precise positioning of the ablation profile as they detect and compensate cyclorotation.

Wellenfrontanalyse zur Diagnose des subklinischen Keratokonus

BACKGROUND

The entity of subclinical keratoconus (SKC) has not been defined sufficiently yet. The aim of the study was to describe ocular wavefront aberrations of clinically inconspicuous fellow eyes in patients with early keratoconus (KC) as a model of SKC and to assess the feasibility of higher-order wavefront analysis to discriminate eyes with SKC from normal eyes.

METHODS

This prospective study included eight clinically inconspicuous fellow eyes of eight patients with newly detected KC in the contralateral eye and a paracentral inferior-superior difference (PISD) <1.4 D. In total, 15 eyes of 12 patients with newly diagnosed KC and a PISD >1.4 D were included as positive controls and 71 healthy eyes of 40 patients served as negative controls. The wavefront error was measured in all eyes with a Hartmann-Shack sensor. Discriminant analysis was performed with input from ocular HOA data and PISD. Receiver operating characteristic (ROC) curves were plotted for PISD, single Zernike coefficients, and for the output values of the discriminant functions to investigate their usefulness for discrimination between SKC eyes, early KC eyes, and healthy controls.

RESULTS

There were significant differences between inconspicuous fellow eyes (group 2) and controls (group 3) for PISD, for the coefficients Z3(-3), Z3(-1), Z4(0) and Z5(-1), and for the output values of the discriminant functions. The latter discriminated between groups 2 and 3 with maximum sensitivity and specificity (A(z) ROC=1), whereas discriminative ability was considerably lower for single Zernike coefficients.

CONCLUSION

Single Zernike coefficients did not appear to be useful for the detection of SKC. Using discriminant analysis, from PISD and higher-order Zernike coefficients a metric with very high discriminative ability between normal and SKC eyes could be constructed.

Soluble tumour necrosis factor receptor treatment does not affect raised transforming growth factor beta levels in rheumatoid arthritis

OBJECTIVE

To further elucidate the immunomodulating effects of anti-tumour necrosis factor alpha treatment in rheumatoid arthritis (RA) by studying changes in plasma levels of transforming growth factor beta (TGFbeta) in patients with RA undergoing etanercept treatment.

METHODS

Plasma levels of TGFbeta1 and TGFbeta2 were determined in 26 patients with RA during six months of etanercept treatment and compared with disease activity and laboratory parameters, including matrix metalloproteinase-3 (MMP-3) and interleukin 6 (IL6).

RESULTS

Before treatment all patients had raised TGFbeta1, IL6, and MMP-3 levels. In the course of treatment IL6 and MMP-3 levels decreased significantly, accompanied by a drop in serological markers (C reactive protein and erythrocyte sedimentation rate) and clinical disease activity (visual analogue scale and Thompson joint score). By contrast, high levels of latent TGFbeta1 were present in all specimens over the entire six months. TGFbeta2 levels did not change during treatment.

CONCLUSION

Etanercept treatment induces subtle changes in the cytokine network. Although the proinflammatory cytokine IL6 is down regulated, the persistence of high TGFbeta plasma levels indicates the existence of as yet unknown mechanisms for TGFbeta overexpression in RA. This may predispose to severe infections and can cause an altered tumour defence.

The HPV-16 E7 oncoprotein binds Skip and suppresses its transcriptional activity

E7 is the major transforming protein of human papillomavirus (HPV), which is implicated in the development of cervical cancer. The transforming activity of E7 has been attributed in part to its interaction with the retinoblastoma (Rb) tumour suppressor; however, the Rb interaction alone is not sufficient for transformation by E7. In a screen for cellular targets of HPV E7, we identified the Ski interacting protein, Skip, as a new interacting partner of E7. We show that HPV-16 E7 associates with Skip via sequences in its carboxy terminal region, and the evolutionarily conserved proline rich sequences (PRS) of the SNW domain of Skip. E7 functionally targets Skip in vivo and inhibits its transcriptional activation activity. Two transformation defective mutants of E7 were identified that failed both to bind Skip and to inhibit its transcriptional activity. These results suggest that inhibition of Skip function may contribute to cell transformation by HPV-16 E7.

Regulation of the human papillomavirus oncoproteins by differential phosphorylation

Human papillomaviruses (HPVs) are intimately associated with the development of cervical cancer. The virus encodes two oncoproteins, E6 and E7, that are primarily responsible for inducing malignant transformation. The last few years have seen significant progress in elucidating the mechanisms by which these two viral proteins bring about cell transformation. Both proteins interact with a large number of cellular targets, many of which are involved in regulating diverse functions such as cell cycle regulation, transcription, differentiation and apoptosis. However both E6 and E7 are normally present at low levels within the virally infected cell, and how all these interactions are achieved and regulated has, until recently, been unclear. We have found that both E6 and E7 are subject to differential phosphorylation, the net results of which regulate their abilities to interact with some of their respective target proteins. In the case of E6, phosphorylation by Protein Kinase A (PKA) negatively regulates its ability to interact with the Discs Large (Dlg) tumour suppressor. In the case of E7, phosphorylation by Casein Kinase II (CKII) significantly increases its ability to interact with the TATA Box Binding Protein (TBP). Further, CKII regulation of E7 appears to vary during the cell cycle, therefore this provides a means of specifically targeting E7 to a given substrate at a given point within the cell cycle. This differential regulation of E6 and E7 by phosphorylation thus provides specificity to a diverse set of protein-protein interactions.

Ski interacts with the evolutionarily conserved SNW domain of Skip

Ski interacting protein (Skip) has been found to bind to the highly conserved region of Ski, which is required for its transforming activity. Ski is a unique oncoprotein that is involved in inducing both transformation and differentiation. At the molecular level, Ski has been shown to exhibit either co-activator or co-repressor activity depending on the cellular and promoter context. We were interested in further elucidating the biological implications of the Ski-Skip interaction. Here we have identified the SNW domain of Skip as the interaction region for Ski. This domain of Skip is highly conserved in all the Skip homologues identified from different species. Using a series of reporter plasmids, we show that Skip is a potent transcriptional activator of many different promoters, the activity of which was also mapped to the conserved core SNW domain of the protein. Addition of excess Ski further augmented the transcriptional activities of Skip, suggesting that one of the ways in which Ski brings about transformation is by binding and cooperating with the SNW domain of Skip in transcriptional activation.

Differential regulation of human papillomavirus E6 by protein kinase A: conditional degradation of human discs large protein by oncogenic E6

The protein Kinase A (PKA) pathway was found to selectively regulate the function of oncogenic but not non-oncogenic E6 proteins. High risk E6 proteins are phosphorylated at their Dlg/PDZ binding motif at the C-terminus by a PKA like activity. This PKA and PDZ binding module is found only for human PV, is strictly conserved in all the transforming HPVs and is absent in all the low risk HPV types. We present evidence of a conditional regulation of E6 induced degradation of Dlg. HPV18E6 positive but not HPV negative keratinocytes exhibit increased Dlg steady state levels under conditions of high PKA activity, with a concomitant increase in the presence of Dlg at tight junctions. In vitro binding experiments show that E6 phosphorylation by PKA reduces its binding to Dlg and molecular modelling can explain this observation in a structural context. E6 dependent degradation of Dlg in cells with high PKA levels is inhibited and this is dependent on phosphorylation of the PDZ binding site in E6. In contrast, the degradation of p53 induced by E6 is not affected by PKA. We propose a differential regulation of E6 for the ubiquitin mediated degradation of specific E6 target proteins.

Oncogenic human papillomavirus E6 proteins target the discs large tumour suppressor for proteasome-mediated degradation

Previous studies have shown that the oncogenic HPV E6 proteins form a complex with the human homologue of the Drosophila tumour suppressor protein, discs large (Dlg). This is mediated by the carboxy terminus of the E6 proteins and involves recognition of at least one PDZ domain of Dlg. This region of E6 is not conserved amongst E6 proteins from the low risk papillomavirus types and, hence, binding of HPV E6 proteins to Dlg correlates with the oncogenic potential of these viruses. We have performed studies to investigate the consequences of the interaction between E6 and Dlg. Mutational analysis of both the HPV18 E6 and Dlg proteins has further defined the regions of E6 and Dlg necessary for complex formation. Strikingly, co-expression of wild type HPV18 E6 with Dlg in vitro or in vivo results in a dramatic decrease in the amount of Dlg protein, whereas mutants of E6 which fail to complex with Dlg have minimal effect on Dlg protein levels. The oncogenic HPV16 E6 also decreased the Dlg levels, but this was not observed with the low risk HPV11 E6 protein. Moreover, a region within the first 544 amino acids of Dlg containing the three PDZ domains confers susceptibility to E6 mediated degradation. Finally, treatment of cells with a proteasome inhibitor overrides the capacity of E6 to degrade Dlg. These results demonstrate that Dlg is targeted by high risk HPV E6 proteins for proteasome mediated degradation.

Molecular genetic characterisation of intracerebrally transplanted brain tumours

The aim of the present study was the characterisation of genetic alterations in two different experimental gliomas, induced in rats from the inbred strain BDIX by transplacental ethylnitrosourea with subsequent serial transplantation. The genes investigated have been shown previously to be altered during human glial tumour progression and include the gene for the epidermal growth factor receptor (EGFR), the genes for the cell cycle regulators cyclin dependent kinase 4 (CDK4), cyclinD1 (cycD1), the p16 gene (MTS1/INK4) and the retinoblastoma gene (RB). Using a semi-quantitative PCR-based screening method no gross alterations could be detected in these genes, demonstrating that nitrosourea-induced glial tumours of rats do not harbour those genetic changes which typically arise in human malignant gliomas. Thus, the use of this tumour model for gene therapy trials is questionable.

E3-ubiquitin ligase/E6-AP links multicopy maintenance protein 7 to the ubiquitination pathway by a novel motif, the L2G box

Ubiquitin ligases are generally assumed to play a major role in substrate recognition and thus provide specificity to a particular ubiquitin modification system. The multicopy maintenance protein (Mcm) 7 subunit of the replication licensing factor-M was identified as a substrate of the E3-ubiquitin ligase/E6-AP by its interaction with human papillomavirus-18E6. Mcm7 is ubiquitinated in vivo in both an E6-AP-dependent and -independent manner. E6-AP functions in these reactions independently of the viral oncogene E6. We show that recognition of Mcm7 by E6-AP is mediated by a homotypic interaction motif present in both proteins, called the L2G box. These findings served as the basis for the definition of substrate specificity for E6-AP. A small cluster of proteins whose function is intimately associated with the control of cell growth and/or proliferation contains the L2G box and is thereby implicated in an E6-AP and, by default, HPV-E6-dependent ubiquitination pathway.

[Routine hip ultrasonography in inflammatory rheumatoid diseases. Results in 119 consecutive patients of a rheumatism clinic]

METHOD

In 119 consecutive inpatients with rheumatic diseases--mainly rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis--both hips were routinely investigated by sonography.

RESULTS

In 52 of the 119 patients definite or possible pathological findings (in 18 cases bilateral) were observed. The relative frequency of sonographic findings in 223 evaluable hips was 33% and was somewhat higher in patients with rheumatoid arthritis than in those with other diagnoses. Changes were found significantly more often when the patient had joint complaints, limitation of movement, pathological X-ray changes or serological signs of inflammation (elevated ESR, positive C-reactive protein). The relative frequencies were higher than were expected on the basis of data in the literature. Of the pathological sonographic findings, 22% occurred in clinically and radiologically asymptomatic patients.

CONCLUSIONS

In view of the therapeutic consequences and the importance of early treatment, routine sonographic examination of the hip joint is recommended.

Cell cycle regulation of p70 S6 kinase and p42/p44 mitogen-activated protein kinases in Swiss mouse 3T3 fibroblasts

We show here using synchronized Swiss mouse 3T3 fibroblasts that p70 S6 kinase (p70S6k) and mitogen-activated protein kinases (p42mapk/p44mapk) are not only activated at the G0/G1 boundary, but also in cells progressing from M into G1. p70S6k activity increases 20-fold in G1 cells released from G0. Throughout G1, S, and G2 it decreases constantly, so that during M phase low kinase activity is measured. The kinase is reactivated 10-fold when cells released from a nocodazole-induced metaphase block enter G1 of the next cell cycle. p42mapk/p44mapk in G0 cells are activated transiently early in G1 and are reactivated late in mitosis after nocodazole release. p70S6k activity is dependent on permanent signaling from growth factors at all stages of the cell cycle. Immunofluorescence studies showed that p70S6k and its isoform p85S6k become concentrated in localized spots in the nucleus at certain stages in the cell cycle. Cell cycle-dependent changes in p70S6k activity are associated with alterations in the phosphorylation state of the protein. However, examination of the regulation of a p70S6k mutant in which the four carboxyl-terminal phosphorylation sites are changed to acidic amino acids suggests that a mechanism independent of these phosphorylation sites controls the activity of the enzyme during the cell cycle.

Scp160p, a new yeast protein associated with the nuclear membrane and the endoplasmic reticulum, is necessary for maintenance of exact ploidy

We have cloned a new gene, SCP160, from Saccharomyces cerevisiae, the deduced amino acid sequence of which does not exhibit overall similarity to any known yeast protein. A weak resemblance between the C-terminal part of the Scp160 protein and regulatory subunits of cAMP-dependent protein kinases from eukaryotes as well as the pstB protein of Escherichia coli was observed. The SCP160 gene resides on the left arm of chromosome X and codes for a polypeptide of molecular weight around 160 kDa. By immunofluorescence microscopy the Scp160 protein appears to be localized to the nuclear envelope and to the endoplasmic reticulum (ER). However, no signal sequence or membrane-spanning region exists, suggesting that the Scp160 protein is attached to the cytoplasmic surface of the ER-nuclear envelope membranes. Disruption of the SCP160 gene is not lethal but results in cells of decreased viability, abnormal morphology and increased DNA content. This phenotype is not reversible by transformation with a plasmid carrying the wild-type gene. Crosses of SCP160 deletion mutant strains among each other or with unrelated strains lead to irregular segregation of genetic markers. Taken together the data suggest that the Scp160 protein is required during cell division for faithful partitioning of the ER-nuclear envelope membranes which in S. cerevisiae enclose the duplicated chromosomes.

[Clinical relevance of the antiphospholipid syndrome. Antiphospholipid antibodies in a mixed rheumatologic patient sample]

The antiphospholipid syndrome may occur either in association with systemic lupus erythematosus (SLE) or as a primary condition. Diagnostic criteria include the detection of antiphospholipid antibodies using cardiolipin antigen (anticardiolipin antibodies, ACA) or lupus anticoagulant, and at least two clinical manifestations, primarily venous or arterial thrombosis, thrombocytopenia or repeated miscarriage. Among 200 patients with various rheumatic diseases, a pathological ACA test in excess of 44 U/ml was detected with ELISA in 81 cases (41%), and of these 30% had values exceeding 100 U/ml. Both overall positive reactions and the particularly high titers were clearly more common among patients with rheumatoid arthritis (RA) and collagen disease, namely 51% and 33%, respectively, than in patients with sero-negative spondylarthritis and non-inflammatory diseases of the locomotory system (22% pathological, 13% highly pathological, titers. Correlations were also found with miscarriage in women, positive rheumatoid and antinuclear factors, and the number of diagnostic criteria of RA or SLE presenting. A questionnaire survey - evaluating 84 subjects, half with positive and half with negative, ACA reactions - confirmed the correlation between miscarriage and the detection of ACA.

A new pair of B-type cyclins from Saccharomyces cerevisiae that function early in the cell cycle

Two new B-type cyclin genes from Saccharomyces cerevisiae, called CLB5 and CLB6, are located in a tail to tail arrangement adjacent to the G2/M phase promoting cyclins CLB2 and CLB1, respectively. These genomic cyclin arrays are flanked by tRNAs and repeated sequences of Ty elements suggesting an intrachromosomal gene duplication followed by an interchromosomal gene duplication. Based on their deduced protein sequence the CLB5 and CLB6 genes form a new pair of B-type cyclins. They are most related to each other and then to the deduced protein sequence of their adjacent genes CLB1 and CLB2. Both genes are periodically expressed, peaking early in the cell cycle. Loss of function mutants are viable, but clb5- mutants exhibit a delay in S phase whereas clb6- mutants show a delay in late G1 and/or S phase. The clb5 mutant phenotype is somewhat more pronounced in a double null mutant. Both cyclins have the potential to interact with the p34CDC28 kinase in vivo.