Wavelength-scale errors in optical localization due to spin-orbit coupling of light.

Far-field optical imaging techniques allow the determination of the position of point-like emitters and scatterers [1-3]. Although the optical wavelength sets a fundamental limit to the image resolution of unknown objects, the position of an individual emitter can in principle be estimated from the image with arbitrary precision. This is used for example in the determination of stars position [4] or in optical super-resolution microscopy [5]. Furthermore, precise position determination is an experimental prerequisite for the manipulation and measurement of individual quantum systems, such as atoms, ions, and solid-state-based quantum emitters [6-8]. Here we demonstrate that spin-orbit coupling of light in the emission of elliptically polarized emitters can lead to systematic, wavelength-scale errors in the estimation of the emitters position. Imaging a single trapped atom as well as a single sub-wavelength-diameter gold nanoparticle, we demonstrate a shift between the emitters measured and actual positions which is comparable to the optical wavelength. For certain settings, the expected shift can become arbitrarily large. Beyond optical imaging techniques, our findings could be relevant for the localization of objects using any type of wave that carries orbital angular momentum relative to the emitters position with a component orthogonal to the direction of observation.

Vitamins E, A and B2 as Possible Risk Factors for Preeclampsia - under Consideration of the PROPER Study ("Prevention of Preeclampsia by High-Dose Riboflavin Supplementation").

In the course of the prospective, randomized, double-blind trial the influence of a high-dose riboflavin substitution on the risk for preeclampsia was studied in a high-risk collective 1. The present contribution evaluates supplementary data from the already published PROPER trial. The patients were from the two study centers Mérida, Venezuela, and Moshi, Tanzania, they were randomized from the 20th week of pregnancy and received either 15 mg riboflavin daily or placebo. Clinical and laboratory checks were carried out at four-week intervals up to childbirth. Concerning the question of whether there is a relationship between the serum levels of antioxidative vitamins and the risk of developing preeclampsia, it was found that no relationship could be detected between the measured laboratory values of vitamins E, A and B2 and the total risk of developing a hypertensive disease of pregnancy. On comparisons between patients with severe preeclampsia, those with a mild form, and the general healthy population, however, significant differences in the levels of antioxidative vitamins E and A as well as the FAD level were seen. The patients from Tanzania showed on the whole significantly lower vitamin levels than those from Venezuela, possibly due to the better nutritional situation in Venezuela. Considering the results altogether, the role of antioxidative parameters in the pathophysiology of preeclampsia remains unclear. However, the collected data provide valuable hints for future preventative strategies.

Towards long-distance atom-photon entanglement.

We report the observation of entanglement between a single trapped atom and a single photon at remote locations. The degree of coherence of the entangled atom-photon pair is verified via appropriate local correlation measurements, after communicating the photon via an optical fiber link of 300 m length to a receiver 3.5 m apart. In addition, we measured the temporal evolution of the atomic density matrix after projecting the atom via a state measurement of the photon onto several well-defined spin states. We find that the state of the single atom dephases on a time scale of 150 micros, which represents an important step towards long-distance quantum networking with individual neutral atoms.

Mass spectrometric analysis of head-to-tail connected cyclic peptides.

Tandem mass spectrometry is an extremely useful tool for high sensitive sequence identification of peptides. In the case of cyclic peptides fragmentation can easily be performed for sequence analysis. However, analysis is usually tedious due to the lack of a defined beginning and end of the sequence. Since cyclic peptides are a highly interesting class of compounds especially for the pharmaceutical industry, ways have to be found to identify their strictures. In this work we demonstrate how software and dedicated analytical strategies can be used for detailed analysis of these substances.

Modulation of tumor-induced lethality after pneumoperitoneum in a mouse model.

BACKGROUND: To the authors' knowledge, a generally accepted approach to prevent increased intraabdominal tumor implantation after laparoscopic cancer surgery does not exist. METHODS: One week after establishing an ovarian carcinoma cell line in black mice intraabdominally (n = 156), a carbon dioxide pneumoperitoneum (Group 1: n = 78) was administered. The effect of this procedure on tumor-induced lethality and the therapeutic effect of mitoxantrone and taurolidin mixed with heparin and sodium chloride was investigated. The different drugs were added immediately after the release of the pneumoperitoneum and after 48 hours. The 78 control animals received the drugs at the same time without preexisting pneumoperitoneum. Survival time was registered. RESULTS: The survival time was reduced significantly in all pneumoperitoneum groups compared with the corresponding control group without pneumoperitoneum. The effect of mitoxantrone on survival time (mean, 62.08 days) was diminished significantly by the application of a pneumoperitoneum (mean, 34.27 days). Taurolidine/heparin appeared to have a positive effect on survival time only in the case of a previous pneumoperitoneum (mean of 21.12 days vs. mean of 16.04 days in the pneumoperitoneum control group; P < 0.001). CONCLUSIONS: The induction of a pneumoperitoneum appears to decrease survival time by increasing tumor cell growth and decreases the efficacy of intraperitoneal chemotherapy. The effects of pneumoperitoneum appear to be reduced by the use of heparin/taurolidine, which theoretically blocks extracellular matrix binding domains and inhibits the production of interleukin-1.

Riboflavin deficiency and preeclampsia.

OBJECTIVE: To examine in a prospective study riboflavin deficiency as a predisposing factor for preeclampsia in a high-risk collective of pregnant women in Zimbabwe. METHODS: At an antenatal clinic in Bulawayo, Zimbabwe, 154 women at increased risk for preeclampsia were observed prospectively until delivery. Riboflavin status was determined using the erythrocyte glutathione reductase activation coefficient test on the day of antenatal booking. Riboflavin deficiency was expressed by erythrocyte glutathione reductase activation coefficient of 1.4 or greater. RESULTS: Riboflavin deficiency was frequently found among the study population (33.8%). Incidence rose toward the end of pregnancy (27.3% at 29-36 weeks' gestation compared with 53.3% at over 36 weeks). In the riboflavin-deficient group, mothers were more likely to develop preeclampsia (28.8%) than in the riboflavin-adequate group (7.8%; P <.001, odds ratio [OR] 4.7, 95% confidence interval [CI] 1.8-12.2). The calculated concentrations of intracellular free flavin adenine dinucleotide were significantly lower in patients who developed preeclampsia than in normal pregnancies (P <.05). CONCLUSION: Riboflavin deficiency should be considered a possible risk factor for preeclampsia. Insufficient concentrations of the riboflavin-derived cofactors flavin adenine dinucleotide and flavin adenine mononucleotide could contribute to the established pathophysiologic changes including mitochondrial dysfunction, enhanced oxidative stress, and disturbances in nitric oxide release.

Determination of the cellular retinoic-acid-binding protein in dysplastic epithelia of the cervix uteri, differentiated into apo and holo forms.

PURPOSE: The appearance of the cervical mucosa is regulated by different factors including retinoic acid. Hormone-dependent alteration of the cervix uteri mucosa is accompanied by a decrease or increase of cytoplasmatic retinoic-acid-binding protein (CRABP). To elucidate whether this hormone-dependent alteration of CRABP is preserved in the case of neoplasms of the cervix uteri, we measured the level of total and apo-CRABP in normal and neoplastically transformed cervical cells. METHODS: In a prospective pilot study, standardised biopsies of normal epithelium and cervical intra-epithelial neoplasm grade 3 (CIN III) were taken from 24 patients. A newly developed method was used to determine the intra-epithelial level of apo- and total CRABP. RESULTS: The concentration of total CRABP in normal squamous epithelium compared with that in intra-epithelial neoplasm grade 3 is very significantly lower in the CIN III areas (normal: 3.66 +/- 1.46 pmol/ mg wet weight +/- SD; CIN III 1.43 +/- 0.59 pmol/mg P < 0.01). In addition CRABP in the apo form is lower in normal than in neoplastic epithelium (Wilcoxon test for paired non-parametric values: P < 0.05; mean for all patients: normal: 1.65 + 0.82 pmol/mg; CIN III: 1.14 +/- 0.23 pmol/mg). CONCLUSION: From our results we conclude that, in neoplastically transformed cells, the hormone-dependent CRABP cycle is interrupted. Whether this has consequences for the further development of the neoplastic cells has to be elucidated.

The influence of pneumoperitoneum used in laparoscopic surgery on an intraabdominal tumor growth.

BACKGROUND: Numerous clinical reports have raised the possibility that laparoscopic cancer surgery has an inherently detrimental effect on tumor growth. The aim of the current study was to examine the influence of a pneumoperitoneum on the morphology of the peritoneum and the intraperitoneal tumor cell implantation and growth in the case of intraabdominal spread of tumor cells. METHODS: Black mice were stratified into 2 groups of 36 animals each. A CO(2) pneumoperitoneum was induced for 30 minutes in Group 1 and 200,000 cells of a malignant melanoma were injected intraperitoneally. In Group 2 only tumor cells were injected. After a defined period of hours, 4 animals were killed and the peritoneum was examined by scanning electron microscopy. RESULTS: In Group 1, starting 2 hours after release of the pneumoperitoneum, strong alterations of the peritoneum became visible and parts of the underlying basal lamina were laid bare. Tumor cells attached to the free basal lamina and formed predominantly diffuse metastases throughout the peritoneum within the next 96 hours. No diffuse changes of the peritoneal surface and no diffuse metastases were observed in the second group. Singular metastases followed gravity and involved the anterior abdominal wall. CONCLUSIONS: Because these findings explain the clinical findings of intraabdominal metastases after laparoscopy the authors conclude that the pneumoperitoneum provokes particular damage to the peritoneum that induces a specific intraperitoneal tumor growth. [See also editorial counterpoint on pages 747-8 and reply to counterpoint on pages 749-50, this issue.

[A scanning microscopy study of the peritoneum in mice after application of a CO2-pneumoperitoneum]. / Rasterelektronenmikroskopische Untersuchungen am Peritoneum der Maus nach Anlage eines CO2-Pneumoperitoneums.

OBJECTIVE: The application of a CO2-pneumoperitoneum in operative laparoscopy presumably leads to basic alterations of the intraperitoneal homeostasis. In order to better understand the pathophysiology of this phenomenon, the morphologic alterations of the mesothelium after CO2-application will be examined. MATERIAL AND METHODS: In 36 mice (C 57, black mice) a CO2-pneumoperitoneum with an intraperitoneal pressure of 6 mm Hg was applied for 30 minutes. After 1, 2, 6, 12, 24, 48, 72 and 96 hours each of 4 animals were killed and the entire peritoneum was examined by scanning electron microscopy. RESULTS: Already after 1 hour mesothelial cells became cuboidal, were detached and showed condensation. After 2 hours this initial reaction reached its peak; immature cells then attached to the free basal membrane. After 96 hours the entire mesothelium was regenerated. CONCLUSIONS: The morphologic integrity of the mesothelium is temporarily disturbed by a CO2-pneumoperitoneum. Reasons for this phenomenon may be either the abdominal pressure or a CO2-induced surface acidosis. In further studies, the influence of the described phenomena on intraperitoneal formation of metastases will be examined.

Characteristic alterations of the peritoneum after carbon dioxide pneumoperitoneum.

OBJECTIVE: Any route of entry into the abdomen contributes to alterations of the intraperitoneal organs with different clinical consequences. Characteristic alterations of the peritoneum after CO2 pneumoperitoneum used in laparoscopic surgery is examined. METHODS: A CO2 pneumoperitoneum with an intraperitoneal pressure of 6 mmHg was applied for 30 min in 32 nude mice. In the course of 4 days, the animals were killed and the peritoneal surface of the abdominal wall was studied by means of scanning electron microscopy. RESULTS: Already 2 h after release of the pneumoperitoneum, mesothelial cells were bulging up. The intercellular clefts thereby increased in size, and the underlying basal lamina became visible. This reaction peaked after 12 h. Subsequently, peritoneal macrophages and lymphocytes filled all gaps, thereby recovering the basal lamina. CONCLUSION: The morphologic integrity of the peritoneum is temporarily disturbed by a CO2 pneumoperitoneum.

Synthesis and structural characterization of human-identical lung surfactant SP-C protein.

An efficient synthesis for human-identical lung surfactant protein SP-C is described with a semi-automated solid phase synthesizer using Fmoc chemistry. Double coupling and acetic anhydride capping procedures were employed for synthetic cycles within the highly hydrophobic C-terminal domain of SP-C. Isolation of the protein was performed by mild cleavage and deprotection conditions and subsequent HPLC purification yielding a highly homogeneous protein as established by sequence determination, electrospray, plasma desorption and MALDI mass spectrometry. A general method has been employed for the preparation of Cys-palmitoylated protein by using temporary Cys(tButhio) protection, in situ deprotection with beta-mercaptoethanol and selective palmitoylation of resin-bound SP-C. The mild synthesis and isolation conditions provide SP-C with a high alpha-helical content, comparable to that of the natural SP-C, as assessed by CD spectra. Furthermore, first biophysical data indicate a surfactant activity comparable to that of the natural protein.

Laparoscopic surgery: the effects of insufflation gas on tumor-induced lethality in nude mice.

OBJECTIVE: The aim of the study was to examine the effect of helium (group 2), carbon dioxide (group 3), and heated carbon dioxide (group 4) pneumoperitoneum on survival in case of intraabdominal spread of tumor cells in nude mice. STUDY DESIGN: The pneumoperitoneum was induced by a microhysteroflator with an intraperitoneal pressure of 8 mm Hg for 30 minutes. A washed tumor solution (0.4 ml) of a mesothelioma was injected intraperitoneally. RESULTS: The survival rate of group 3 was significantly reduced compared with the controls (group 1) and group 4. The latter groups showed similar survival rates. In groups 2 and 3 no significant differences in survival rate were observed. CONCLUSION: Clinical observations and the results of this animal study warn against the use of standard unheated carbon dioxide pneumoperitoneum in case of malignant tumors. Heated carbon dioxide seems to be advantageous.

Molecular characterization of metal-binding polypeptide domains by electrospray ionization mass spectrometry and metal chelate affinity chromatography.

Metal ion-binding of synthetic peptides containing HxH and CxxC motifs was investigated by electrospray ionization mass spectrometry (ESI-MS) and metal chelate affinity chromatography. A high affinity of Ni2+ and Cu2+ to HxH containing sequences was found. Based on their natural metal ion-binding potential it was possible to include metal affinity chromatography in the purification process of two proteins without using an additional His-tag sequence: ATPase-439, a P type ATPase from Helicobacter pylori and the amyloid precursor protein (APP).

Properties of the P-type ATPases encoded by the copAP operons of Helicobacter pylori and Helicobacter felis.

The cop operons of Helicobacter pylori and Helicobacter felis were cloned by gene library screening. Both operons contain open reading frames for a P-type ion pump (CopA) with homology to Cd2+ and Cu2+ ATPases and a putative ion binding protein (CopP), the latter representing a CopZ homolog of the copYZAB operon of Enterococcus hirae. The predicted CopA ATPases contained an N-terminal GMXCXXC ion binding motif and a membrane-associated CPC sequence. A synthetic N-terminal peptide of the H. pylori CopA ATPase bound to Cu2+ specifically, and gene disruption mutagenesis of CopA resulted in an enhanced growth sensitivity of H. pylori to Cu2+ but not to other divalent cations. As determined experimentally, H. pylori CopA contains four pairs of transmembrane segments (H1 to H8), with the ATP binding and phosphorylation domains lying between H6 and H7, as found for another putative transition metal pump of H. pylori (K. Melchers, T. Weitzenegger, A. Buhmann, W. Steinhilber, G. Sachs, and K. P. Schäfer, J. Biol. Chem. 271:446-457, 1996). The corresponding transmembrane segments of the H. felis CopA pump were identified by hydrophobicity analysis and via sequence similarity. To define functional domains, similarly oriented regions of the two enzymes were examined for sequence identity. Regions with high degrees of identity included the N-terminal Cu2+ binding domain, the regions of ATP binding and phosphorylation in the energy transduction domain, and a transport domain consisting of the last six transmembrane segments with conserved cysteines in H4, H6, and H7. The data suggest that H. pylori and H. felis employ conserved mechanisms of ATPase-dependent copper resistance.

Characterization of specific noncovalent protein complexes by UV matrix-assisted laser desorption ionization mass spectrometry.

While electrospray (ESI) mass spectrometry has already established its potential for the characterization of non-covalent protein complexes, matrix-assisted laser desorption/ionization mass spectrometry (MALDI/MS) seemed not to be applicable hitherto because of limitations in matrix chemistry and sample preparation. In this work, a sample preparation method has been developed in which 6-aza-2-thiothymine (ATT) was used as a matrix without any addition of organic cosolvents, and proteins were dissolved in aqueous buffers such as ammonium hydrogencarbonate, ammonium citrate and ammonium acetate. Under these conditions, the intact non-covalent protein complexes, RNAse S, the non-covalent complex of S-protein and S-peptide and specific dimers of coiled-coil leucine zipper polypeptides were observed by UV-MALDI/MS. The specificity of complex formation was ascertained by admixture of non-specific peptides which did not yield detectable aggregate ions. In addition, on-target tryptic digestion of cytochrome c and leucine zipper peptides was carried out after MALDI/MS molecular mass determination in the presence of the ATT matrix. Mass spectrometric analyses of these tryptic digests yielded spectra that showed complete digestion of the proteins. These results indicate that proteins maintained intact tertiary structures necessary for the formation of specific non-covalent complexes, and that trypsin retained its functional enzymatic structure and full biological activity with the present sample preparation method.

[Effect of CO2 pneumoperitoneum on intraperitoneal tumor growth in the animal model]. / Der Einfluss eines CO2-Pneumoperitoneums auf das intraperitoneale Tumorwachstum im Tiermodell.

Clinical observations during recent years describe the increased occurrence of rapid intraperitoneal metastases and an impairment of prognosis if a malignant tumour was operated laparoscopically. It is not known whether the observed induction of intraabdominal metastases after laparoscopic surgery in the result of an inadequate surgical procedure with spillage of tumour cells into the abdominal cavity or whether pneumoperitoneum-induced changes of the peritoneal milieu promote tumour growth. An animal model was established to examine the effect of a CO2-pneumoperitoneum on the intraperitoneal growth of tumour cells. Six week old nude mice were divided into 4 groups of 15 animals each. A CO2-pneumoperitoneum was induced by a micro-hysteroflator with an intraperitoneal pressure of 6 mmHg for 90 minutes in groups 2 and 4. Two different tumour cell lines, suspended in 2 ml of Ringer's solution for homogeneous spread of the cells, were injected i.p.. The control groups 1 and 3 received the tumour cells without pneumoperitoneum induction of a CO2-pneumoperitoneum resulted in an increasing seeding rate of tumour cells and provoked a significant increase in the number and size of intraabdominal metastases. Laparoscopic surgery of malignancies is therefore contraindicated.

[Indications for 3 D laparoscopy in gynecology]. / Zur Indikation der 3 D-Laparoskopie in der Gynäkologie.

In a prospective randomised study we investigated the possibilities of a 3 D-video system in comparison to a 2 D-video system in operative laparoscopy. On 76 patients the following operations were performed: enucleation of fibroids, extirpation of ovarian cysts, fimbrioplasty, tubo-tubal anastomosis and Burch's procedure via preperitoneal access. For microsurgical procedures of the adnexae the new 3 D-technology shows advantages in compared to the standard 2 D-laparoscopy. In these operations the operating area is naturally limited, and hence the disadvantages of the 3 D-technology like limited depth of focus are not important. The 3 D-system allows a very good visualisation even of small structures and safe and exact handling. For surgery of the uterus or larger tumours of the adnexae, the new technology is unsuited.

Pathophysiologic features of a pneumoperitoneum at laparoscopy: a swine model.

OBJECTIVE: The aim of this study was to examine local and systemic reactions of the body to a pneumoperitoneum to elucidate potential dangers and risks of laparoscopic procedures. STUDY DESIGN: Laparoscopy was performed on 25 pigs. The pigs were divided into five groups by level of intraabdominal pressure (14 and 18 mm Hg) and gas used (carbon dioxide and air). The effects of the pneumoperitoneum on cardiopulmonary condition and the peritoneal milieu were observed. These effects should be the result of various changes as the mechanical, ventilatory, cellular, hormonal, and immunologic levels. RESULTS: In this animal study marked changes in the peritoneal milieu were observed, and we demonstrated that these changes were dependent on the gas used, intraabdominal pressure, and duration of application. Locally these changes are manifest in the development of severe peritoneal acidosis, hypercapnia, and the release of various mediators. Systemic changes, in particular cardiopulmonary changes, also depend on the intraabdominal pressure and the gas used. CONCLUSION: During conventional pneumoperitoneum the peritoneum might change to a large extent so that the development of new risks are possibly encouraged. A reduction in intraabdominal pressure with the use of carbon dioxide as the insufflation gas should result in normal acid-base balance.