PSA bounce after <Superscript>125</Superscript>I-brachytherapy for prostate cancer as a favorable prognosticator

Background

Permanent low-dose-rate brachytherapy (BT) with iodine 125 is an established curative treatment for localized prostate cancer. After treatment, prostate-specific antigen (PSA) kinetics may show a transient rise (PSA bounce). Our aim was to investigate the association of PSA bounce with biochemical control.

Patients and methods

Patients treated with BT in Switzerland were registered in a prospective database. Only patients with a follow-up of at least 2 years were included in our analysis. Clinical follow-up and PSA measurements were assessed after 1.5, 3, 6, and 12 months, and annually thereafter. If PSA increased, additional follow-up visits were scheduled. Cases of PSA bounce were defined as a rise of at least 0.2 ng/ml above the initial PSA nadir with a subsequent decline to or below the initial nadir without treatment. Biochemical failure was defined as a rise to nadir +?2 ng/ml.

Results

Between March 2001 and November 2010, 713 patients with prostate cancer undergoing BT with at least 2 years of follow-up were registered. Median follow-up time was 41 months. Biochemical failure occurred in 28 patients (3.9?%). PSA bounce occurred in 173 (24.3?%) patients; only three (1.7?%) patients with PSA bounce developed biochemical failure, in contrast to 25 (4.6?%) patients without previous bounce (p?<?0.05). The median time to bounce was 12 months, the median time to biochemical failure was 30 months. The median bounce increase was 0.78 ng/ml. Twenty-eight patients with bounce (16.5?%) had a transient PSA rise of +?2 ng/ml above the nadir.

Conclusion

In most cases, an early increase in PSA after BT indicates PSA bounce and is associated with a lower risk of biochemical failure.

     

Immunoglobulin G4‐related disease in the urinary bladder

Immunoglobulin G4‐related disease is a fibroinflammatory condition of unclear etiology that can present with inflammatory changes and enlargement of a wide variety of organs, most commonly in the gastrointestinal tract. A diagnosis requires an elevated serum immunoglobulin G4 concentration and a tissue biopsy showing a dense plasma cell infiltrate with an increased percentage of immunoglobulin G4+ plasma cells. This disease infrequently presents in the genitourinary tract, and as such might be unfamiliar to and potentially overlooked by urologists. Here we present the third reported case of immunoglobulin G4‐related disease manifesting as a mass in the urinary bladder.     

Mutations of p53 Tumor Suppressor Gene, Apoptosis, and Proliferation in Intrahepatic Cholangiocellular Carcinoma of the Liver

This study was performed to examine the correlation between mutations of the p53 tumor suppressor gene, the occurrence of apoptosis, and proliferation in cholangiocellular carcinoma of the liver. The results obtained were compared with pathohistological stage (according to UICC) and grade and with disease related survival rate. In 41 curatively (R0–) resected intrahepatic cholangiocellular carcinomas, the status of the p53 gene was determined by direct sequencing of exons 4–9 and immunohistochemically. Apoptosis was assessed using the in situ end labeling (ISEL) technique in combination with morphological criteria. Proliferation was analyzed by immunohistochemistry of MIB-1 (Ki-67), Proliferating cell nuclear antigen (PCNA), and silver-stained nucleolar organizer regions (AgNOR). The results obtained were compared with pathohistological stage (according to UICC), grade, several other histopathological factors, and survival rate. Mutations of p53 were detected in 15/41 carcinomas examined (37%). The most common change was a GC and CT transition, changing the hot spot amino acid determined by exons 4–8. Of these 15 tumors, 14 were also p53-positive by immunohistochemistry. In each carcinoma examined, we could demonstrate MIB-1, PCNA, and AgNOR dots and also apoptotic cells in variable proportions. The proliferation markers showed a significant correlation among themselves. In univariate survival analysis, the extent of the primary tumor, lymph node status, grade, and p53 were significant factors influencing patient survival. Performing multivariate Cox regression survival analysis, however, only the extent of primary tumor and lymph node status had an independent prognostic impact. Apoptosis was not related to patient prognosis or to other parameters examined. In conclusion, these results indicated that p53 could serve as an additional prognostic parameter that could provide auxiliary information for patient outcome. However, tumor stage and lymph node involvement were the strongest prognostic factors. We failed to establish apoptosis or other pathological parameters as factors predicting the prognosis of patients with cholangiocellular carcinoma.     

From the Cover: Breaking the diffraction limit of light-sheet fluorescence microscopy by RESOLFT

We present a plane-scanning RESOLFT [reversible saturable/switchable optical (fluorescence) transitions] light-sheet (LS) nanoscope, which fundamentally overcomes the diffraction barrier in the axial direction via confinement of the fluorescent molecular state to a sheet of subdiffraction thickness around the focal plane. To this end, reversibly switchable fluorophores located right above and below the focal plane are transferred to a nonfluorescent state at each scanning step. LS-RESOLFT nanoscopy offers wide-field 3D imaging of living biological specimens with low light dose and axial resolution far beyond the diffraction barrier. We demonstrate optical sections that are thinner by 5–12-fold compared with their conventional diffraction-limited LS analogs.Far-field nanoscopy (1, 2) methods discern features within subdiffraction distances by briefly forcing their molecules to two distinguishable states for the time period of detection. Typically, fluorophores are switched between a signaling “on” and a nonsignaling (i.e., dark) “off” state. Depending on the switching and fluorescence registration strategy used, these superresolution techniques can be categorized into coordinate-stochastic and coordinate-targeted approaches (2). The latter group of methods, comprising the so-called RESOLFT [reversible saturable/switchable optical (fluorescence) transitions] (1, 3–7) approaches, have been realized using patterns of switch-off light with one or more zero-intensity points or lines, to single out target point (zero-dimensional) or line (1D) coordinates in space where the fluorophores are allowed to assume the on state. The RESOLFT idea can also be implemented in the inverse mode, by using switch-on light and confining the off state. In any case, probing the presence of molecules in new sets of points or lines at every scanning step produces images.Owing to the nature of the on and off states involved––first excited electronic and ground state––stimulated emission depletion (STED) (3) and saturated structured illumination microscopy (SSIM) (8), which both qualify as variants of the RESOLFT principle, typically apply light intensities in the range of MW/cm² and above. Especially when imaging sensitive samples where photoinduced changes must be avoided, RESOLFT is preferably realized with fluorophores which lead to the same factor of resolution improvement at much lower intensities of state-switching light. Reversibly switchable fluorescent proteins (RSFPs) are highly suitable for this purpose (4–7, 9), as transitions between their metastable on and off states require 5 orders of magnitude lower threshold intensities than STED/SSIM to guarantee switch-off. Suitable spectral properties, relatively fast millisecond switching kinetics, and high photostability of recently developed yellow-green-emitting RSFPs like rsEGFP (5), rsEGFP2 (7), and rsEGFP(N205S) (10) compared with early RSFPs have indeed enabled RESOLFT nanoscopy in living cells and tissues. To date, RSFP-based RESOLFT has achieved resolution improvements by factors of 4–5 in rsEGFP2-labeled samples (7). To further reduce the imaging time, massive parallelization of scanning has been reported (10). However, the diffraction-limited axial resolution and lack of background suppression restrict applications to thin samples.Imaging applications typically require careful tuning of imaging parameters including speed, contrast, photosensitivity, and spatial resolution, depending on the information that is sought. Light-sheet fluorescence microscopy (LSFM) (11–15) stands out by its ability to balance most of these parameters for 3D imaging of living specimens. Recently reenacted as the selective plane illumination microscope (13), this microscopy mode has sparked increasing interest notably because of its short acquisition times in 3D imaging and low phototoxicity in living specimens. It excites fluorophores only in a thin diffraction-limited slice of the sample, perpendicular to the direction of fluorescence detection. The LS is generated by a cylindrical lens which focuses an expanded laser beam in only one direction onto the specimen or into the back-focal plane of an illumination objective. Alternatively, a single beam is quickly moved as a “virtual” LS (16) across a specimen section.In such conventional LSFM imaging, the lateral resolution is determined by the numerical aperture (N.A.) of the detection objective (17), whereas axial resolution is given by the LS thickness, provided the latter is thinner than the axial extent of the point-spread function describing the imaging process from the focal plane of the detecting lens to the camera. In a previous study, the axial resolution of LSFM was pushed to the diffraction limit by using the full aperture of the illumination objective with Gaussian beams; this was carried out for practically useful combinations of N.A. (e.g., 0.8 for both illumination and detection objectives) permissible in light of the geometrical constraints given by the objective lens dimensions (18). High-N.A. illumination comes with short Rayleigh ranges of Gaussian beams, which inherently limit the field of view (FOV) along the direction of illumination. Scanned Bessel beams for diffraction-limited excitation with a virtual LS (19–21) typically offer larger FOVs (22), but side lobes broaden the scanned LS in the axial direction and contribute to phototoxicity outside of the focal plane of detection (20). A more complex approach has used Bessel-beam excitation in combination with structured illumination to obtain near-isotropic (but still diffraction-limited) resolution as measured on fluorescent beads (20), albeit at the cost of acquisition time and reduced contrast due to fluorescence generated by the side lobes. In different work, axial resolution has also been improved about fourfold by acquiring two complementary orthogonal views of the sample using two alternating LSs, followed by computationally fusing image information with a deconvolution incorporating both views (23). LS approaches have also helped suppress out-of-focus background for single-molecule imaging in biological situations (e.g., in ref. 24), including at superresolution (25–27).Slight axial resolution improvement beyond the diffraction barrier has been demonstrated by overlapping a Gaussian excitation LS with a STED LS featuring a zero-intensity plane (28). Due to scattering and possibly additional aberrations caused by the wavelength difference between excitation and STED light, the maximal achievable resolution in biological specimens was severely limited. This was the case even in fixed samples. A successful application of LS-STED to living cells or organisms has not been reported. The relatively high average STED laser power required for high resolution gains calls for developing a coordinate-targeted superresolution LS approach with low-power operation, meaning a concept that does not solely rely on changing the way the light is directed to––or collected from––the sample, but a concept that harnesses an “on–off” transition for improved feature separation.     

Comparison of N-glycan pattern of recombinant human coagulation factors II and IX expressed in Chinese hamster ovary (CHO) and African green monkey (Vero) cells

The N-glycan patterns of recombinant human coagulation factors II (rF-II) and IX (rF-IX), derived from both transfected Chinese hamster ovary (CHO) cells and African green monkay (Vero) cells produced at industrial scale, were analyzed by binding to carbohydrate-specific lectins and were compared with the glycan structure of human plasma-derived coagulation factors. Human plasma-derived coagulation factors II (hpF-II) and IX (hpF-IX) exhibited complex-type glycan structures with carbohydrate chains capped with (2–6)-sialic acid. Terminal galactose-(1–4)-N-acetylglucosamine units were detected in hpF-IX. Both CHO cell-derived rF-II and rF-IX exhibited complex-type glycosylation and contained (2–3)-sialic acid in addition to terminal galactose-(1–4)-N-acetylglucosamine. Vero cell-derived rF-IX exhibited a complex-type glycan structure similar to that of CHO cell-derived rF-IX. In contrast, rF-II produced by Vero cells exhibited a glycan microheterogeneity composed of hybrid-type glycosylation containing high-mannose structures and complex-type glycosylation containing (2–3)-sialic acid. Galactose-(1–4)-N-acetylglucosamine structures and a low concentration of (2–6)-sialic acid were detected in both microheterogeneity fractions of Vero cell-derived rF-II. Although different in their carbohydrate structures, coagulation factors II and IX obtained recombinantly from both transformed CHO cells and Vero cells exhibited coagulation activities comparable with the plasma-derived proteins.