Recombinant Acid Ceramidase Reduces Inflammation and Infection in Cystic Fibrosis

Rationale: In cystic fibrosis the major cause of morbidity and mortality is lung disease characterized by inflammation and infection. The influence of sphingolipid metabolism is poorly understood with a lack of studies using human airway model systems.Objectives: To investigate sphingolipid metabolism in cystic fibrosis and the effects of treatment with recombinant human acid ceramidase on inflammation and infection.Methods: Sphingolipids were measured using mass spectrometry in fully differentiated cultures of primary human airway epithelial cells and cocultures with Pseudomonas aeruginosa. In situ activity assays, Western blotting, and quantitative PCR were used to investigate function and expression of ceramidase and sphingomyelinase. Effects of treatment with recombinant human acid ceramidase on sphingolipid profile and inflammatory mediator production were assessed in cell cultures and murine models.Measurements and Main Results: Ceramide is increased in cystic fibrosis airway epithelium owing to differential function of enzymes regulating sphingolipid metabolism. Sphingosine, a metabolite of ceramide with antimicrobial properties, is not upregulated in response to P. aeruginosa by cystic fibrosis airway epithelia. Tumor necrosis factor receptor 1 is increased in cystic fibrosis epithelia and activates NF-κB signaling, generating inflammation. Treatment with recombinant human acid ceramidase, to decrease ceramide, reduced both inflammatory mediator production and susceptibility to infection.Conclusions: Sphingolipid metabolism is altered in airway epithelial cells cultured from people with cystic fibrosis. Treatment with recombinant acid ceramidase ameliorates the two pivotal features of cystic fibrosis lung disease, inflammation and infection, and thus represents a therapeutic approach worthy of further exploration.

Comparison between ultrasonography and X-ray as evaluation methods of central venous catheter positioning and their complications in pediatrics

PURPOSE

This study evaluates the capacity of ultrasonography as a diagnostic method to confirm the proper positioning of central venous catheter (CVC) when compared to the current gold standard, chest radiography (CR).

METHODS

A prospective study was performed including children from 0 to 14 incomplete years, who underwent CVC placement between March and May 2018 at a teaching hospital in Brazil. A four-chamber view of the heart was performed with ultrasound during a rapid injection of saline solution to identify hyperechoic images and confirm the central position of the catheter. After that, a CR was performed. The diagnostic quality of ultrasound was evaluated based on accuracy, sensitivity, specificity, positive and negative predictive values.

RESULTS

A total of 21 patients were analyzed. The mean age was 3.95 ± 4.01 years. The preferred puncture site was the right internal jugular vein (71.4%). Ultrasound accuracy to detect CVC positioning was 81%. Sensitivity, specificity and positive and negative predictive values were 33%, 100%, 100% and 79%, respectively.

CONCLUSION

Ultrasound is a reliable method for detection of CVC positioning. Even so, with the four-chamber cardiac view, this method is unable to identify catheters inside heart chambers, therefore, needing to confirm the positioning with CR.

Role of 1-Deoxysphingolipids in docetaxel neurotoxicity

A major dose-limiting side effect of docetaxel chemotherapy is peripheral neuropathy. Patients' symptoms include pain, numbness, tingling and burning sensations, and motor weakness in the extremities. The molecular mechanism is currently not understood, and there are no treatments available. Previously, we have shown an association between neuropathy symptoms of patients treated with paclitaxel and the plasma levels of neurotoxic sphingolipids, the 1-deoxysphingolipids (1-deoxySL) (Kramer et al, FASEB J, 2015). 1-DeoxySL are produced when the first enzyme of the sphingolipid biosynthetic pathway, serine palmitoyltransferase (SPT), uses L-alanine as a substrate instead of its canonical amino acid substrate, L-serine. In the current investigation, we tested whether 1-deoxySL accumulate in the nervous system following systemic docetaxel treatment in mice. In dorsal root ganglia (DRG), we observed that docetaxel (45 mg/kg cumulative dose) significantly elevated the levels of 1-deoxySL and L-serine-derived ceramides, but not sphingosine-1-phosphate (S1P). S1P is a bioactive sphingolipid and a ligand for specific G-protein-coupled receptors. In the sciatic nerve, docetaxel decreased 1-deoxySL and ceramides. Moreover, we show that in primary DRG cultures, 1-deoxysphingosine produced neurite swellings that could be reversed with S1P. Our results demonstrate that docetaxel chemotherapy up-regulates sphingolipid metabolism in sensory neurons, leading to the accumulation of neurotoxic 1-deoxySL. We suggest that the neurotoxic effects of 1-deoxySL on axons can be reversed with S1P.

Intestinal Acid Sphingomyelinase Protects From Severe Pathogen-Driven Colitis

Inflammatory diseases of the gastrointestinal tract are emerging as a global problem with increased evidence and prevalence in numerous countries. A dysregulated sphingolipid metabolism occurs in patients with ulcerative colitis and is discussed to contribute to its pathogenesis. In the present study, we determined the impact of acid sphingomyelinase (Asm), which catalyzes the hydrolysis of sphingomyelin to ceramide, on the course of Citrobacter (C.) rodentium-driven colitis. C. rodentium is an enteric pathogen and induces colonic inflammation very similar to the pathology in patients with ulcerative colitis. We found that mice with Asm deficiency or Asm inhibition were strongly susceptible to C. rodentium infection. These mice showed increased levels of C. rodentium in the feces and were prone to bacterial spreading to the systemic organs. In addition, mice lacking Asm activity showed an uncontrolled inflammatory T_h1 and T_h17 response, which was accompanied by a stronger colonic pathology compared to infected wild type mice. These findings identified Asm as an essential regulator of mucosal immunity to the enteric pathogen C. rodentium.

T Cell-Specific Overexpression of Acid Sphingomyelinase Results in Elevated T Cell Activation and Reduced Parasitemia During Plasmodium yoelii Infection

The enzyme acid sphingomyelinase (ASM) hydrolyzes sphingomyelin to ceramide and is thereby involved in several cellular processes such as differentiation, proliferation, and apoptosis in different cell types. However, the function of ASM in T cells is still not well characterized. Here, we used T cell-specific ASM overexpressing mice (t-ASM/CD4cre) to clarify the impact of cell-intrinsic ASM activity on T cell function in vitro and in vivo. We showed that t-ASM/CD4cre mice exhibit decreased frequencies of Foxp3⁺ T regulatory cells (Tregs) within the spleen. Enforced T cell-specific ASM expression resulted in less efficient induction of Tregs and promoted differentiation of CD4⁺CD25⁻ naïve T cells into IFN-γ producing Th1 cells in vitro. Further analysis revealed that ASM-overexpressing T cells from t-ASM/CD4cre mice show elevated T cell receptor (TCR) signaling activity accompanied with increased proliferation upon stimulation in vitro. Plasmodium yoelii infection of t-ASM/CD4cre mice resulted in enhanced T cell activation and was associated with reduced parasitemia in comparison to infected control mice. Hence, our results provide evidence that ASM activity modulates T cell function in vitro and in vivo.

Comparison of Anterior Chamber Depth Measurements using Orbscan II and IOLMaster

PURPOSE

To evaluate and compare anterior chamber depth (ACD) measurements using Orbscan II (Bausch & Lomb, Rochester, NY) and IOLMaster (Carl Zeiss Meditec AG, Jena, Germany).

METHODS

In this prospective clinical study, the authors measured ACD of 145 phakic eyes of 30 healthy volunteers and 115 patients using Orbscan II and IOLMaster. Average patient age was 52.9+/-19.4 (range 16 to 87) years. ACD was evaluated from corneal epithelium to anterior lens surface. Additionally, axial length (AL) was measured using the Zeiss IOLMaster to calculate the regression coefficient between AL and ACD.

RESULTS

Mean ACD was 3.35+/-0.43 mm (range 2.01 mm to 4.37 mm) using Orbscan II and 3.36+/-0.41 mm (range 2.09 mm to 4.24 mm) using IOLMaster. Mean total axial length was 24.04 mm +/- 2.1 mm (range 20.7 mm to 31.41 mm). The linear regression coefficient of ACD between both methods was R=0.95. ACD and AL correlated only slightly (R=0.57). The Spearman coefficients of rank correlation were 0.94 and 0.61, respectively. A p value less than 0.01 (paired Wilcoxon test) was considered statistically significant. However, a significant difference was not calculated comparing ACD measurements using both systems and the Bland-Altman-Plot showed 95% of the differences ranging between 0.25 and -0.27 mm.

CONCLUSIONS

Regarding clinical application, both systems seem to be equally good and interchangeable in clinical practice in terms of ACD evaluation.

Effects of green tea compound epigallocatechin-3-gallate against Stenotrophomonas maltophilia infection and biofilm

We investigated the in vitro and in vivo activities of epigallocatechin-3-gallate (EGCg), a green tea component, against Stenotrophomonas maltophilia (Sm) isolates from cystic fibrosis (CF) patients. In vitro effects of EGCg and the antibiotic colistin (COL) on growth inhibition, survival, and also against young and mature biofilms of S. maltophilia were determined. Qualitative and quantitative changes on the biofilms were assessed by confocal laser scanning microscopy (CLSM). Further, in vivo effects of nebulized EGCg in C57BL/6 and Cftr mutant mice during acute Sm lung infection were evaluated. Subinhibitory concentrations of EGCg significantly reduced not only biofilm formation, but also the quantity of viable cells in young and mature biofilms. CLSM showed that EGCg-exposed biofilms exhibited either a change in total biofilm biovolume or an increase of the fraction of dead cells contained within the biofilm in a dose depended manner. Sm infected wild-type and Cftr mutant mice treated with 1,024 mg/L EGCg by inhalation exhibited significantly lower bacterial counts than those undergoing no treatment or treated with COL. EGCg displayed promising inhibitory and anti-biofilm properties against CF Sm isolates in vitro and significantly reduced Sm bacterial counts in an acute infection model with wild type and CF mice. This natural compound may represent a novel therapeutic agent against Sm infection in CF.

Acid sphingomyelinase-ceramide system mediates effects of antidepressant drugs

Major depression is a highly prevalent severe mood disorder that is treated with antidepressants. The molecular targets of antidepressants require definition. We investigated the role of the acid sphingomyelinase (Asm)-ceramide system as a target for antidepressants. Therapeutic concentrations of the antidepressants amitriptyline and fluoxetine reduced Asm activity and ceramide concentrations in the hippocampus, increased neuronal proliferation, maturation and survival and improved behavior in mouse models of stress-induced depression. Genetic Asm deficiency abrogated these effects. Mice overexpressing Asm, heterozygous for acid ceramidase, treated with blockers of ceramide metabolism or directly injected with C16 ceramide in the hippocampus had higher ceramide concentrations and lower rates of neuronal proliferation, maturation and survival compared with controls and showed depression-like behavior even in the absence of stress. The decrease of ceramide abundance achieved by antidepressant-mediated inhibition of Asm normalized these effects. Lowering ceramide abundance may thus be a central goal for the future development of antidepressants.

Genauigkeit der Linsenstärkenberechnung und Zentrierung einer asphärischen Intraokularlinse

BACKGROUND

Aspherical intraocular lenses (IOLs) are presumed to optimize the optical characteristics of IOLs. In order to profit from these characteristics, exact calculation of the IOL power and good centration of the lens are essential.

METHODS

In all, 43 eyes of 43 patients with an average age of 70.9+/-8.3 years underwent implantation of a Tecnis IOL (AMO, Ettlingen) after uneventful cataract surgery with topical anesthesia. IOL power calculation was performed using the Holladay, Haigis, and SRK II formulas. Spherical equivalent refraction and centration and position of the implanted IOLs were measured 6 months postoperatively. Centration of the IOL was analyzed using digital slit lamp photographs and an image analysis program.

RESULTS

Best corrected visual acuity (BCVA) increased from 0.47+/-0.25 (LogMAR) preoperatively to 0.1+/-0.11 6 months postoperatively (spherical equivalent +0.3+/-0.6 D). The intraindividual difference between target refraction and achieved postoperative refraction was 0.64+/-0.11 D for the Holladay formula, -0.21+/-0.11 D for the Haigis formula, and 0.97+/-0.15 D for the SRK II formula. The mean decentration of the IOL from the center of the corneal limbus was 0.4+/-0.1 mm.

CONCLUSIONS

For the aspherical Tecnis IOL very good postoperative functional results are reported, which are supported by an accurate calculation of the IOL power and a good centration of the IOL inside the capsular bag. In this study the Haigis formula showed the lowest difference between target refraction and achieved postoperative refraction.

Identification of a dynein interacting domain in the papillomavirus minor capsid protein l2

Papillomaviruses enter cells via endocytosis (H. C. Selinka et al., Virology 299:279-287, 2002). After egress from endosomes, the minor capsid protein L2 accompanies the viral DNA to the nucleus and subsequently to the subnuclear promyelocytic leukemia protein bodies (P. M. Day et al., Proc. Natl. Acad. Sci. USA 101:14252-14257, 2004), suggesting that this protein may be involved in the intracytoplasmic transport of the viral genome. We now demonstrate that the L2 protein is able to interact with the microtubule network via the motor protein dynein. L2 protein was found attached to microtubules after uncoating of incoming human papillomavirus pseudovirions. Based on immunofluorescence and coimmunoprecipitation analyses, the L2 region interacting with dynein is mapped to the C-terminal 40 amino acids. Mutations within this region abrogating the L2/dynein interaction strongly reduce the infectivity of pseudoviruses, indicating that this interaction mediates the minus-end-directed transport of the viral genome along microtubules towards the nucleus.

PresbyLASIK

Presbyopia represents the most common refractive error. There is currently no surgical treatment for presbyopia, which is effective, reliable, and safe. Excimer laser surgery has become a routine procedure for the correction of myopia, hyperopia, and astigmatism for years. Various treatment strategies for presbyopia have been brought forward using the excimer lasers. Besides monovision, creation of a multifocal cornea represents an attractive option. This procedure is also called "PresbyLASIK." Different ablation profiles to form a multifocal cornea are reviewed here and first clinical results are summarized."PresbyLASIK" is a new, interesting treatment strategy, with a huge potential for the future. At the present it should be used in controlled studies only because of some unsolved questions.

Prospective, non-randomised, long term clinical evaluation of a foldable hydrophilic single piece intraocular lens: results of the Centerflex FDA study

BACKGROUND

Owing to the improvement of modern intraocular lenses (IOLs) in terms of design and material, posterior capsule opacification (PCO) usually takes 2-3 years to develop. Thus, long term clinical evaluation of new implants is important.

METHODS

As part of a prospective, non-randomised FDA trial, the Rayner Centerflex, a foldable hydrophilic acrylic, single piece IOL was implanted in one eye of 83 patients (mean age 73.5 (SD 7.0) years). Over 3 years postoperatively, a standardised FDA protocol concerning IOL safety and efficacy was followed including evaluation of spherical equivalent (SE), best corrected distance visual acuity (BCDVA), endothelial cell count (ECC), flare meter values, PCO development, and anterior capsule shrinkage.

RESULTS

Postoperatively, mean SE was stable ranging between -0.3D and 0.17D. After 1-2 months, all patients achieved a BCDVA of 20/40 or better. At 3-6 months postoperatively, mean ECC decreased from 2612 (SD 346) cells/mm2 to 2380 (316) cells/mm2. Mean PCO score for the entire optic increased from 0.20 (0.20) months (3-6 months postoperatively) to 0.87 (0.57) resulting in a Nd:YAG rate of 29.41% after 3 years. No anterior capsule shrinkage was found.

CONCLUSION

The Centerflex showed excellent functional results, low values for endothelial cell loss and inflammatory signs, and no anterior capsule shrinkage. PCO formation was higher compared to other IOLs, which could be explained by the incomplete sharp edge at the optic-haptic junctions representing an "Achilles' heel" for cell ingrowth.

Nuclear translocation of papillomavirus minor capsid protein L2 requires Hsc70

Minor capsid protein L2 of papillomaviruses plays an essential role in virus assembly by recruiting viral components to PML bodies, the proposed sites of virus morphogenesis. We demonstrate here that the function of L2 in virus assembly requires the chaperone Hsc70. Hsc70 was found dispersed in naturally infected keratinocytes and cultured cells. A dramatic relocation of Hsc70 from the cytoplasm to PML bodies was induced in these cells by L2 expression. Hsc70-L2 complex formation was confirmed by coimmunoprecipitation. The complex was modulated by the cochaperones Hip and Bag-1, which stabilize and destabilize Hsc70-substrate complexes, respectively. Cytoplasmic depletion of Hsc70 caused retention of wild-type and N-terminally truncated L2, but not of C-terminally truncated L2, in the cytoplasm. This retention was partially reversed by overexpression of Hsc70 fused to green fluorescent protein but not by ATPase-negative Hsc70. Hsc70 associated with L1-L2 virus-like particles (VLPs) but not with VLPs composed either of L1 alone or of L1 and C-terminally truncated L2. Moreover, displacement of Hsc70 from L1-L2 VLPs by encapsidation of DNA, generating pseudovirions, was found. These data indicate that Hsc70 transiently associates with viral capsids during the integration of L2, possibly via the L2 C terminus. Completion of virus assembly results in displacement of Hsc70 from virions.

Messmethode zur Bestimmung der Rotation und der Dezentrierung von Intraokularlinsen

PURPOSE

In the past 50 years the IOL has been improved. Nowadays it is possible to exactly calculate the necessary IOL power and correct toric refractive errors. In this study we developed methods for measuring rotation and decentration using the example of a hydrophilic acrylic IOL.

METHODS

Following cataract surgery, the first retroilluminated photograph was taken. The position of the IOL was determined with the image analysis program Adobe Photoshop.

RESULTS

Measurement of a rotational movement or of a decentration of an IOL can be done accurately and rapidly. Evaluation of the stability of rotation of the hydrophilic acrylic IOL measured here showed an average rotation of the IOL of 5.3+/-1.4 degrees after 6 months compared to the position directly after implantation.

CONCLUSION

The measurement methods presented here are easy to use and provide reliable results. Examiners must have basic knowledge of the computer programs used. Also, these methods depend on good quality of the retroilluminated photographs.

Nuclear localization but not PML protein is required for incorporation of the papillomavirus minor capsid protein L2 into virus-like particles

Recent reports suggest that nuclear domain(s) 10 (ND10) is the site of papillomavirus morphogenesis. The viral genome replicates in or close to ND10. In addition, the minor capsid protein, L2, accumulates in these subnuclear structures and recruits the major capsid protein, L1. We have now used cell lines deficient for promyelocytic leukemia (PML) protein, the main structural component of ND10, to study the role of this nuclear protein for L2 incorporation into virus-like particles (VLPs). L2 expressed in PML protein knockout (PML(-/-)) cells accumulated in nuclear dots, which resemble L2 aggregates forming at ND10 in PML protein-containing cells. These L2 assemblies also attracted L1 and the transcriptional repressor Daxx, suggesting that they are functional in the absence of PML protein. In addition, L2-containing VLPs assembled in PML(-/-) cells. In order to analyze whether incorporation of L2 into VLPs requires any specific subcellular localization, an L1 mutant defective for nuclear transport and L2 mutants deficient in nuclear translocation and/or ND10 localization were constructed. Using this approach, we identified two independent L2 domains interacting with L1. Mutant L2 proteins not accumulating in ND10 were incorporated into VLPs. Mutant L1 protein, which assembled into VLPs in the cytoplasm, did not incorporate L2 defective for nuclear translocation. The same mutant L2 protein, which passively diffuses into the nucleus, is incorporated into wild-type L1-VLPs in the nucleus. Our data demonstrate that the incorporation of L2 into VLPs requires nuclear but not ND10 localization.

Dissection of human papillomavirus type 33 L2 domains involved in nuclear domains (ND) 10 homing and reorganization

We have recently shown that the minor capsid protein L2 of human papillomavirus type 33 (HPV33) recruits the transcriptional repressor Daxx into nuclear domains (ND) 10 and causes the loss of the transcriptional activator Sp100 from these subnuclear structures. In order to dissect L2 domains involved in nuclear translocation, ND10 homing, loss of Sp100, and recruitment of Daxx, a detailed deletion mutagenesis of L2 was performed. Using immunofluorescence and green fluorescent protein fusions, we have identified two nuclear localization signals (NLS) in the central and C-terminal part of L2, respectively, homologous to previously identified NLS in HPV6B L2 (Sun et al., 1995). We mapped the ND10 localization domain to within a 30 amino acid peptide in the C-terminal half of L2. L2-induced attraction of Daxx into ND10, coimmunoprecipitation of L2 and Daxx, as well as induction of the loss of Sp100 from ND10 require an intact ND10 localization domain. This domain contains conserved PXXP motives characteristic of some protein/protein interacting domains. Our data also suggest that the Daxx/L2 interaction may be the driving force for L2 accumulation in ND10.

[Validity of anterior chamber depth measurements for the evaluation of accommodation after implantation of an accommodative Humanoptics 1CU intraocular lens]

BACKGROUND

Changes in the anterior chamber depth (ACD) after pilocarpin application are generally regarded as reflecting an accommodative effect of accommodative intraocular lenses (IOLs)

METHODS

We implanted Humanoptics 1CU accommodative IOLs into 25 eyes of 20 patients aged 53.2+/-14.7 years (range: 30-83 years). In seven of these patients, we were able to measure anterior chamber depth changes after the application of pilocarpine (2%) eye drops 3 months postoperatively using a Zeiss IOLMaster, an Orbscan II topography system, as well as by ultrasound biomicroscopy (20 MHz-US-head).

RESULTS

Uncorrected near acuity was on average 0.4+/-0.23 (0.1-0.8) and uncorrected distance acuity was 0.76+/-0.23 (0.3-1). Before pilocarpine, ACD was 3.19+/-2.11 mm (IOL-Master), 3.35+/-2.22 mm (Orbscan II) and 3.35+/-2.21 mm (US-biomicroscopy) ( P=0.96). After pilocarpine, ACD was 2.61+/-1.71 mm (IOL-Master), 2.63+/-1.78 mm (Orbscan II) and 3.15+/-2.08 mm (US-biomicroscopy) ( P=0.002). The average individual ACD change before/after pilocarpine was 0.83+/-0.25 mm with the IOL-Master, 1.04+/-0.39 mm with the Orbscan II System and 0.28+/-0.14 with US-biomicroscopy ( P=0.0004).

DISCUSSION

The 1CU Humanoptics accommodative IOL presented with potential accommodative capabilities in clinical evaluation. Drug induced accommodation by pilocarpine does not reflect real accommodative effects. The differences in ACD measurements between three different methods were statistically significant. Evaluation methods for accommodative IOLs should be carefully analysed and further development of objective means for evaluation is needed.

[Miyake-Apple video analysis of movement patterns of an accommodative intraocular lens implant]

BACKGROUND

The potentially accommodative intraocular lens (IOL) is a new development in IOL design

METHODS

We evaluated the new Humanoptics 1CU accommodative IOL in a laboratory study with human post mortem autopsy eyes. Using the Miyake-Apple posterior view video technique, the movement pattern of the IOL was tested and observed from the posterior perspective. RESULTS. A circular bend at the level of the ciliary body applied slight circular force onto the sclera allowing the relaxation of the zonules. The shift of focus was demonstrated by using a reading target. In addition, viscoelastic was injected into the vitreous resulting in the same anterior movement of the IOL optic.

CONCLUSIONS

The 1CU Humanoptics accommodative IOL showed potential accommodative behaviour in the laboratory. The accommodative (respectively pseudoaccommodative) effect was based on the anterior shift principle with anterior movement of the IOL-optic in the state of relaxing zonules. Whether this reflects the clinical situation, especially to this extent, must be further evaluated.

Syndecan-1 is required for Wnt-1-induced mammary tumorigenesis in mice

Syndecan-1 is a cell-surface, heparan-sulphate proteoglycan (HSPG) predominantly expressed by epithelial cells. It binds specifically to many proteins, including oncoproteins. For example, it induces the assembly of a signalling complex between FGF ligands and their cognate receptors. But so far there has been no direct evidence that this proteoglycan contributes to tumorigenesis. Here we have examined the role of syndecan-1 (encoded by Sdc1) during mammary tumour formation in response to the ectopic expression of the proto-oncogene Wnt1. We crossed syndecan-1-deficient mice with transgenic mice that express Wnt1 in mammary gland (TgN(Wnt-1)1Hev; ref. 2). Ectopic Wnt-1 expression induces generalized mammary hyperplasia, followed by the development of solitary tumours (median time 22 weeks). We show that in Sdc1-/- mice, Wnt-1-induced hyperplasia in virgin mammary gland was reduced by 70%, indicating that the Wnt-1 signalling pathway was inhibited. Of the 39 tumours that developed in a test cohort of mice, only 1 evolved in the Sdc1-/- background. In addition, we show that soluble syndecan-1 ectodomain purified from mouse mammary epithelial cells stimulates the activity of a Wnt-1 homologue in a tissue culture assay. Our results provide both genetic and biochemical evidence that syndecan-1 can modulate Wnt signalling, and is critical for Wnt-1-induced tumorigenesis of the mouse mammary gland.

The influence of inspiratory hyperoxia on ischemia-reperfusion-induced tumour growth delay

We investigated the ischemia-reperfusion-induced tumour growth delay as a function of ischemic time, tumour temperature, and the amount of inspired oxygen during reperfusion. The rhabdomyosarcoma R1H growing on the right flank of male WAG/Rij rats was clamped for 2 or 4 h at 20 degrees C or 37 degrees C. Five minutes prior to and 10 min during reperfusion the animals respired air, pure oxygen or carbogen (95% O2, 5% CO2). Comparison of single treatment modalities with untreated controls revealed significant tumour growth delays after clamping times of 4 h at 37 degrees C for air and pure oxygen, but not for carbogen.

Reorganization of filamentous actin and myosin-II in zebrafish eggs correlates temporally and spatially with cortical granule exocytosis

The zebrafish egg provides a useful experimental system to study events of fertilization, including exocytosis. We show by differential interference contrast videomicroscopy that cortical granules are: (1) released nonsynchronously over the egg surface and (2) mobilized to the plasma membrane in two phases, depending upon vesicle size and location. Turbidometric assay measurements of the timing and extent of exocytosis revealed a steady release of small granules during the first 30 seconds of egg activation. This was followed by an explosive discharge of large granules, beginning at 30 seconds and continuing for 1–2 minutes. Stages of single granule exocytosis and subsequent remodeling of the egg surface were imaged by either real-time or time-lapse videomicroscopy as well as scanning electron microscopy. Cortical granule translocation and fusion with the plasma membrane were followed by the concurrent expansion of a fusion pore and release of granule contents. A dramatic rearrangement of the egg surface followed exocytosis. Cortical crypts (sites of evacuated granules) displayed a purse-string-like contraction, resulting in their gradual flattening and disappearance from the egg surface. We tested the hypothesis that subplasmalemmal filamentous (F-) actin acts as a physical barrier to secretion and is locally disassembled prior to granule release. Experimental results showed a reduction of rhodamine-phalloidin and antimyosin staining at putative sites of secretion, acceleration of the timing and extent of granule release in eggs pretreated with cytochalasin D, and dose-dependent inhibition of exocytosis in permeabilized eggs preincubated with phalloidin. An increase in assembled actin was detected by fluorometric assay during the period of exocytosis. Localization studies showed that F-actin and myosin-II codistributed with an inward-moving, membrane-delimited zone of cytoplasm that circumscribed cortical crypts during their transformation. Furthermore, cortical crypts displayed a distinct delay in transformation when incubated continuously with cytochalasin D following egg activation. We propose that closure of cortical crypts is driven by a contractile ring whose forces depend upon dynamic actin filaments and perhaps actomyosin interactions.

Leg ulceration and the cholesterol embolus

An important and frequently overlooked cause of leg ulcers are cholesterol emboli. A 79-year-old woman with a non-healing leg ulcer is described. The diagnosis of cholesterol embolism was made with the aid of a deep biopsy of the ulcer and serial sectioning of the specimen. This report serves to illustrate the importance of considering cholesterol embolism when evaluating a chronic leg ulcer, and the diagnostic value of proper biopsy techniques.

The cortical actin cytoskeleton of unactivated zebrafish eggs: spatial organization and distribution of filamentous actin, nonfilamentous actin, and myosin-II

Actin and nonmuscle myosin heavy chain (myosin-II) have been identified and localized in the cortex of unfertilized zebrafish eggs using techniques of SDS-polyacrylamide gel electrophoresis, immunoblotting, and fluorescence microscopy. Whole egg mounts, egg fragments, cryosections, and cortical membrane patches probed with rhodamine phalloidin, fluorescent DNase-I, or anti-actin antibody showed the cortical cytoskeleton to contain two domains of actin: filamentous and nonfilamentous. Filamentous actin was restricted to microplicae and the cytoplasmic face of the plasma membrane where it was organized as an extensive meshwork of interconnecting filaments. The cortical cytoplasm deep to the plasma membrane contained cortical granules and sequestered actin in nonfilamentous form. The cytoplasmic surface (membrane?) of cortical granules displayed an enrichment of nonfilamentous actin. An antibody against human platelet myosin was used to detect myosin-II in whole mounts and egg fragments. Myosin-II colocalized with both filamentous and nonfilamentous actin domains of the cortical cytoskeleton. It was not determined if egg myosin was organized into filaments. Similar to nonfilamentous actin, myosin-II appeared to be concentrated over the surface of cortical granules where staining was in the form of patches and punctate foci. The identification of organized and interconnected domains of filamentous actin, nonfilamentous actin, and myosin-II provides insight into possible functions of these proteins before and after fertilization.

The sperm entry site during fertilization of the zebrafish egg: localization of actin

The sperm entry site (SES) of zebrafish (Brachydanio rerio) eggs was studied before and during fertilization by fluorescence, scanning, and transmission electron microscopy. Rhodamine phalloidin (RhPh), used to detect polymerized filamentous actin, was localized to microvilli of the SES and to cytoplasm subjacent to the plasma membrane in the unfertilized egg. The distribution of RhPh staining at the SES correlated with the ultrastructural localization of a submembranous electrondense layer of cortical cytoplasm approximately 500 nm thick and containing 5- to 6-nm filaments. Actin, therefore, was organized at the SES as a tightly knit meshwork of filaments prior to fertilization. Contact between the fertilizing sperm and the filamentous actin network was observed by 15-20 sec postinsemination or just before the onset of fertilization cone formation. Growing fertilization cones of either artificially activated or inseminated eggs exhibited intense RhPh staining and substantial increase in thickness of the actin meshwork. Collectively, TEM and RhPh fluorescence images of inseminated eggs demonstrated that the submembranous actin became rearranged in fertilization cones to form a thickened meshwork around the sperm nucleus during incorporation. The results reported here suggest that activation of the egg triggers a dramatic polymerization of actin beneath the plasma membrane of the fertilization cone. Furthermore, the actin involved in sperm incorporation is sensitive to the action of cytochalasins.

A prospective study of intrauterine insemination of processed sperm from men with oligoasthenospermia in superovulated women

The effectiveness of intrauterine insemination (IUI) was compared with that of intracervical insemination (ICI) in 49 infertile couples, in whom the major cause for infertility was oligoasthenospermia. All women had ovulation stimulated with either a clomiphene citrate (CC)-human gonadotropin combination or human gonadotropins alone. The ovulatory dose of human chorionic gonadotropin (hCG) was given after adequate estradiol levels were reached. The timing of inseminations was standardized--IUI was 28 hours after hCG and ICI was immediately after hCG administration. Only one insemination per month was performed with either IUI or ICI. The first treatment cycle was assigned randomly to be either IUI or ICI, and subsequent inseminations were alternated. A total of 182 cycles were completed, with 96 IUIs and 86 ICIs. Pregnancy occurred in eight patients, seven with IUI (14.3%) and one with ICI (2.0%); the difference is significant at P less than 0.05. The pregnancy rate per treatment cycle was 7.3% versus 1.2% (P less than 0.001). This study supports the use of IUI with processed sperm in the treatment of infertility due to oligoasthenospermia.