Evaluation of human polyomavirus BK as a potential cause of villitis of unknown etiology and spontaneous abortion.

Polyomavirus BK (BKV) is a widely latent pathogen in man. Although viral reactivation during pregnancy has been demonstrated, and polyomaviruses have been linked to chromosomal abnormalities, a pathogenic role for BKV in fetoplacental disease has not been explored. We performed in situ hybridization studies with BKV probes on cases of villitis of unknown etiology (102), diffuse villitis (25), and spontaneous abortion (22). We found no evidence that BKV plays a role in the pathogenesis of these common fetoplacental disorders.

Compact ultrafast orthogonal acceleration time-of-flight mass spectrometer for on-line gas analysis by electron impact ionization and soft single photon ionization using an electron beam pumped rare gas excimer lamp as VUV-light source.

Orthogonal acceleration time-of-flight mass spectrometers (oaTOFMS), which are exhibiting a pulsed orthogonal extraction of ion bunches into the TOF mass analyzer from a continuous primary ion beam, are well-suited for continuous ionization methods such as electron impact ionization (EI). Recently an electron beam pumped rare gas excimer lamp (EBEL) was introduced, which emits intensive vacuum UV (VUV) radiation at, e.g., 126 nm (argon excimer) and is well suited as the light source for soft single photon ionization (SPI) of organic molecules. In this paper, a new compact oaTOFMS system which allows switching between SPI, using VUV-light from an EBEL-light source, and conventional EI is described. With the oaTOFMS system, EBEL-SPI and EI mass spectral transients can be recorded at very high repetition rates (up to 100 kHz), enabling high duty cycles and therefore good detection efficiencies. By using a transient recorder card with the capability to perform on-board accumulation of the oaTOF transients, final mass spectra with a dynamic range of 106 can be saved to the hard disk at a rate of 10 Hz. As it is possible to change the ionization modes (EI and SPI) rapidly, a comprehensive monitoring of complex gases with highly dynamic compositions, such as cigarette smoke, is possible. In this context, the EI based mass spectra address the bulk composition (compounds such as water, oxygen, carbon dioxide, etc. in the up to percentage concentration range) as well as some inorganic trace gases such as argon, sulfur dioxide, etc. down to the low ppm level. The EBEL-SPI mass spectra on the other hand are revealing the organic composition down to the lower ppb concentration range.

GRIP deuterium excess reveals rapid and orbital-scale changes in Greenland moisture origin.

The Northern Hemisphere hydrological cycle is a key factor coupling ice sheets, ocean circulation, and polar amplification of climate change. Here we present a Northern Hemisphere deuterium excess profile covering one climatic cycle, constructed with the use of delta18O and deltaD Greenland Ice Core Project (GRIP) records. Past changes in Greenland source and site temperatures are quantified with precipitation seasonality taken into account. The imprint of obliquity is evidenced in the site-to-source temperature gradient at orbital scale. At the millennial time scale, GRIP source temperature changes reflect southward shifts of the geographical locations of moisture sources during cold events, and these rapid shifts are associated with large-scale changes in atmospheric circulation.

Orthogonal time-of-flight secondary ion mass spectrometric analysis of peptides using large gold clusters as primary ions.

Secondary ion mass spectrometry (SIMS) for biomolecular analysis is greatly enhanced by the instrumental combination of orthogonal extraction time-of-flight mass spectrometry with massive gold cluster primary ion bombardment. Precursor peptide molecular ion yield enhancements of 1000, and signal-to-noise improvements of up to 20, were measured by comparing SIMS spectra obtained using Au(+) and massive Au(400) (4+) cluster primary ion bombardment of neat films of the neuropeptide fragment dynorphin 1-7. Remarkably low damage cross-sections were also measured from dynorphin 1-7 and gramicidin S during prolonged bombardment with 40 keV Au(400) (4+). For gramicidin S, the molecular ion yield increases slightly as a function of Au(400) (4+) beam fluence up to at least 2 x 10(13) Au(400) (4+)/cm(2). This is in marked contrast to the rapid decrease observed when bombarding with ions such as Au(5) (+) and Au(9) (+). When gramicidin S is impinged with Au(5) (+), the molecular ion yield decreases by a factor of 10 after a fluence of only 8 x 10(12) ions/cm(2). Comparison of these damage cross-sections implies that minimal surface damage occurs during prolonged Au(400) (4+) bombardment. Several practical analytical implications are drawn from these observations.

The influence of adhesion prophylactic substances and taurolidine/heparin on local recurrence and intraperitoneal tumor growth after laparoscopic-assisted bowel resection of colon carcinoma in a rat model.

BACKGROUND: The goal of the study was to investigate the influence of adhesion prophylactic substances (Interceed/lntergel) as well as taurolidine/heparin on intraperitoneal tumor growth and the local recurrence rate after laparoscopic cecum resection in a rat tumor model. METHODS: Sixty BDIX rats were randomized in three therapy groups and one control group. A laparoscopic-assisted cecum resection was performed via three-trocar method after intraperitoneal tumor cell application (10,000 cells) of a colon carcinoma cell line (DHD/K1/TRb) in all animals. According to the randomization, the cecum suture and a 1 x 1-cm peritoneal defect were either covered with Intergel/Interceed or 1 ml of 0.5% taurolidine 10 IU heparin. The control group underwent instillation of 1 ml 0.9% NaCl solution. After 4 weeks the animals were euthanized and intraperitoneal tumor growth, local recurrence rate, and the number of intraperitoneal adhesions were determined. RESULTS: The local recurrence rate was not significantly affected by any of the substances. Nevertheless, taurolidine/heparin significantly reduced the total number and weight of intraperitoneal metastases. The formation of adhesions was not significantly influenced by adhesion prophylaxis substances or by taurolidine/heparin. CONCLUSIONS: Taurolidine/heparin led to a significant reduction of intraperitoneal tumor growth after intraperitoneal application, whereas local tumor recurrence was not significantly influenced. This might be due to the number of injected tumor cells in this cell suspension model. Interceed and Intergel did not reduce intraperitoneal tumor growth. Furthermore, adhesion formation was not reduced by any of the substances.

Electrospray ionization with ambient pressure ion mobility separation and mass analysis by orthogonal time-of-flight mass spectrometry.

Rapid screening and identification of drug and other mixtures are possible using a novel ambient pressure high-resolution ion mobility (APIMS) orthogonal reflector time-of-flight mass spectrometer (TOFMS). Departing ions from the APIMS drift tube traversed a pressure interface between the APIMS and TOFMS where they were subjected to numerous gas collisions that could produce selective fragmentation. By increasing the accelerating field in the pressure interface region, the ions generated using water-cooled electrospray ionization (ESI) underwent collision-induced dissociation (CID). Mixtures of ESI ions were separated by APIMS based on their respective size-to-charge (s/z) ratios while CID and analysis of mass-to-charge (m/z) ratios occurred in the pressure interface and TOFMS. Product ions that were formed in this pressure interface region could be readily assigned to precursor ions by matching the mobility drift times. This process was demonstrated by the examination of a mixture of amphetamines and the resulting fragmentation patterns of the mobility-separated precursor ion species [M + H](+).

Validation of a new experimental model of colon cancer.

BACKGROUND: Most of the published animal studies that have evaluated tumor growth and port site metastases in laparoscopy have utilized a cell suspension model and thus cannot be compared to the clinical situation. Although solid tumor models have been developed, there has been no experimental model that establishes an orthotopic tumor in the rectum, reflecting the clinical situation of a solid colonic cancer. METHODS: Tumor cells (colon adenocarcinoma DHD/K1/TRb) were administered intraperitoneally in rats, which were used as solid tumor donors. A 20-mg piece of solid tumor from the donor was placed in a submucosal blister created in the rectum wall of the study rats. The approach to the submucosal blister was made through the mucosa after contralateral enterotomy. In order to validate the model, this intervention was performed in 10 cases (group A). After 10 days of intervention, the rats were submitted to resection of the rectum and histological examination of the specimen. In another 10 rats (group B), manipulation of the tumor was performed after 10 days to cause tumor cell spillage. The likelihood of tumor dissemination was investigated in this group 20 days after this intervention. RESULTS: Group A developed solid tumors in seven of 10 cases (70%). All of the tumors were localized between the muscular and the mucosal layer, with preservation of the serosa and without affecting the enterotomy. In all of the rats in group B, macroscopic tumor was observed in the upper rectum (100%) 10 days after its induction. Twenty days after tumor manipulation, nine rats had local tumor dissemination; two of them also had general tumor dissemination in the abdominal cavity. CONCLUSIONS: We established a novel solid colonic tumor model in rats for the investigation of intraoperative tumor cell spillage during resection of the colon and the development of port site metastases.

Surface-induced dissociation on a MALDI-ion mobility-orthogonal time-of-flight mass spectrometer: sequencing peptides from an "in-solution" protein digest.

Peptide sequencing by surface-induced dissociation (SID) on a MALDI-ion mobility-orthogonal TOF mass spectrometer is demonstrated. SID of approximately 100-fmol amounts of model peptides HLGLAR (m/z 666.8), gramicidin S (m/z 1142.5), and bovine insulin b chain (m/z 3495.5) was accomplished using hydrocarbon-coated gold grids and approximately 20-eV collision energies. The current version of the instrument achieves a mobility resolution of approximately 20 and TOF mass resolution better than 200. Peptide sequences of four peptides from a tryptic digest of cytochrome c (approximately 1 pmol deposited) were obtained. The advantage of IM-SID-o-TOF-MS is that a single experiment can be used to simultaneously measure the molecular weights of the tryptic peptide fragments (e.g., peptide mass mapping) and partial sequence analysis, (e.g., real-time tandem mass spectrometry.)

Coupling high-pressure MALDI with ion mobility/orthogonal time-of-flight mass spectrometry.

A new ion mobility/time-of-flight mass spectrometer employing a high-pressure MALDI source has been designed and tested. The prototype instrument operates at a source/drift cell pressure of 1-10 Torr helium, resulting in a mobility resolution of approximately 25. A small time-of-flight mass spectrometer (20 cm) with a mass resolution of up to 200 has been attached to the drift cell to identify (in terms of mass-to-charge ratio) the separated ions. A simple tripeptide mixture has been separated in the drift tube and mass identified as singly protonated species. The ability to separate peptide mixtures, e.g., tryptic digest of a protein, is illustrated and compared to results obtained on a high-vacuum time-of-flight instrument.