Phase-space analysis of double ionization

We use the Wigner transformation to study the electronic center-of-mass motion in phase-space for double ionization in a strong laser field. The rescattering mechanism is clearly visible in the evolution of the fully correlated two-electron system. In a mean-field calculation, on the other hand, the signatures of rescattering are missing. Some properties of the Wigner function in two-particle systems are reported.

Receiver-operating characteristic as a tool for evaluating the diagnostic performance of prostate-specific antigen and its molecular forms--What has to be considered?

BACKGROUND

Receiver-operating characteristic (ROC) analysis is often applied as evaluation tool to compare the diagnostic validity of laboratory tests. The aim of this study was to draw attention to preconditions which should be taken into account when ROC analysis is used to assess the diagnostic performance of total prostate-specific antigen (tPSA) and its molecular forms in differential diagnosis between prostate cancer and benign prostatic hyperplasia (BPH).

METHODS

Using a standard software (GraphROC for Windows), ROC analyses were performed and the areas under the curves were calculated for four hypothetical pairs of groups. Every group included 40 patients with prostate cancer and with BPH showing different tPSA concentrations (range of 2-10 microg, but similar free-to-total PSA ratios (fPSA%).

RESULTS

The area under the fPSA% ROC curve showed the highest value, whereas the areas under the tPSA ROC curves were dependent on the distributions of tPSA concentrations in the patients. The ability of fPSA% to improve the differential diagnosis between prostate cancer and BPH in comparison to tPSA was not furthermore evident, if the prostate cancer group included more patients with higher tPSA concentrations than the BPH group.

CONCLUSIONS

When the diagnostic performance of tPSA and its derivatives like molecular forms in patients with prostate cancer and BPH should be compared by ROC analysis, a matching procedure is recommended prior to ROC analysis to compensate the effect of possible unequal tPSA distributions in both groups. Each BPH (or PCa) patient should be matched with a PCa (or BPH) patient with nearest tPSA concentration so that an optimum of overlapping tPSA concentrations in both groups can be achieved.

Comparison of the clinical validity of free prostate-specific antigen, alpha-1 antichymotrypsin-bound prostate-specific antigen and complexed prostate-specific antigen in prostate cancer diagnosis

OBJECTIVE

To evaluate the diagnostic utility of free prostate specific antigen (fPSA), alpha-1- antichymotrypsin-bound PSA (PSA-ACT), complexed PSA (cPSA), and including their associated ratios to total PSA (tPSA) in serum for discrimination between prostate cancer (PCa) and benign prostatic hyperplasia (BPH).

METHODS

A total of 166 white men (age: 65-88 years) with a tPSA between 2 and 20 microg/l were retrospectively analysed. Serum concentrations of tPSA, fPSA, PSA-ACT and cPSA were measured in 118 untreated PCa patients and 48 patients with BPH. The tPSA and cPSA concentrations were measured with the Bayer Immuno 1 system (Bayer Diagnostics, Tarrytown, USA). The Elecsys system 2010 (Roche Diagnostics, Mannheim, Germany) was used for determination of tPSA and fPSA. The PSA-ACT assay is a newly, developed prototype assay on the ES system (Roche Diagnostics, Mannheim, Germany).

RESULTS

For statistical analysis only patients with tPSA between 2 and 20 microg/l were enrolled. The median concentrations of tPSA (Bayer: PCa 7.36 microg/l, BPH 4.03 microg/l; Roche: PCa 7.75, BPH 4.13), PSA-ACT (PCa 6.98, BPH 3.18) and cPSA (PCa 6.46, BPH 3.20) were significantly different. The median ratios of fPSA/tPSA (PCa 12.8 vs. BPH 22.4%), PSA-ACT/tPSA (PCa 89.8 vs. BPH 76.1%) and cPSA/tPSA (PCa 90.5 vs. BPH 81.7%) were significantly different between PCa and BPH patients. Using the areas under the curves, receiver operating characteristics analysis (tPSA: 2-20 microg/l) for discrimination between PCa and BPH showed that the ratios fPSA/tPSA (area under the curve: 0.77), PSA-ACT/tPSA (0.72) and cPSA/tPSA (0.78) were significantly different from tPSA (Bayer: 0.53; Roche: 0.55). PSA-ACT (0.64) and cPSA (0.59) alone were not significantly different from tPSA. The calculated ratios fPSA/tPSA, PSA-ACT/tPSA and cPSA/tPSA were not significantly different.

CONCLUSION

The determination of PSA-ACT or cPSA and the associated ratios do not improve the diagnostic impact to discriminate between PCa and BPH compared to fPSA/tPSA ratio. The ratios PSA-ACT/tPSA or cPSA/tPSA can be considered to be alternative tools of fPSA/tPSA.

Different stability of free and complexed prostate-specific antigen in serum in relation to specimen handling and storage conditions

The effect of sample collection, storage conditions (time and temperature), and freeze-thaw cycles on the stability of free prostate-specific antigen (fPSA), PSA complexed with alpha1-antichymotrypsin (ACT-PSA), and total PSA (tPSA) in serum was studied. The analytes were quantified using immunoassays for tPSA and fPSA on the Elecsys system 2010 and a research assay for ACT-PSA on the ES system (Roche Diagnostics). The stability of the analytes was calculated as percentages of the values measured in samples 1 h after blood collection. When the samples were stored at 37 degrees C, at room temperature or at 4 degrees C, the stability of ACT-PSA was less impaired than that of fPSA. To avoid erroneous results in the determination of PSA isoforms and their corresponding ratios, serum samples should be preserved at 4 degrees C when the analysis is performed within 8 h after blood collection, or they should be stored at -80 degrees C if the analysis is not feasible during that period.

Intense-field double ionization of helium: identifying the mechanism

We present quantum mechanical calculations of the electron and ion momentum distributions following double ionization of a one-dimensional helium atom by ultrashort laser pulses (780 nm) at various intensities. The two-electron momentum distributions exhibit a clear transition from nonsequential to sequential double ionization. We provide strong evidence that rescattering is responsible for nonsequential ionization by calculating the momentum spectrum of the He2+ recoil ions-which we find in excellent agreement with recent experiments-and by analyzing the electronic center-of-mass motion via Wigner transforms.

Search for a parity-violating energy difference between enantiomers of a chiral iron complex

Mossbauer spectra for l and d enantiomers of the Fe(phen)3Sb2(C4H2O6)(2);8H(2)O complex are reported. Four independent experiments show a small but reproducible energy shift of the Fe-Mossbauer spectra for the two enantiomers of 0.004+/-0. 002 mm/sec ( 1.9x10(-10) eV). This exceedingly small energy difference is comparable to that predicted by the parity-violating energy difference (PVED) using a Z6.2 scaling law applied to low Z ( Z = 6) molecules. Theoretical calculations suggest that the PVED for the Fe(phen)2+3 moiety should be smaller than this estimate, however, PVED effects of the chiral antimony tartrates are not taken into account.

Ratio of alpha 1-antichymotrypsin--prostate specific antigen to total prostate specific antigen in prostate cancer diagnosis

OBJECTIVE

To evaluate the analytical performance and diagnostic utility of prostate specific antigen (PSA) bound to alpha 1-antichymotrypsin (ACT) in serum to improve the differentiation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa).

METHODS

A total of 351 white men 21 to 88 years old were analysed. Serum concentration of tPSA, free PSA (fPSA) and ACT-PSA were measured in 163 untreated PCa patients (median age 66 years), 94 patients with histologically or clinically confirmed BPH (median age 65 years) and 94 men without prostate disease considered as controls (median age 54 years). The Elecsys system 2010 (Roche Diagnostics, Germany) was used for the determinations of tPSA and fPSA. The ACT-PSA assay is a new developed prototype on the ES system (Roche Diagnostics, Germany).

RESULTS

The ACT-PSA assay showed reliable data of analytical performance in comparison to established assays for tPSA and fPSA. The median concentrations of tPSA (PCa: 9.22 micrograms/L, BPH: 2.28 micrograms/L, controls: 0.99 microgram/L) and ACT-PSA (7.99 micrograms/L vs. 1.63 micrograms/L vs. 0.58 microgram/L) were significantly different, respectively. The median ratios of fPSA/tPSA (PCa: 12.3%, BPH: 25.4%), ACT-PSA/tPSA (90.5% vs. 66.6%) and fPSA/ACT-PSA (14.0% vs. 38.6%) were significantly different between PCa and BPH patients. Significant differences of ratios between BPH and controls were not observed. Receiver operating characteristics analysis (tPSA up to 20 micrograms/L) for discrimination between PCa and BPH showed that the ratios fPSA/tPSA (area under the curve: 0.861) and fPSA/ACT-PSA (0.847) were significantly different from tPSA (0.663), but ACT-PSA (0.733) alone and also the ratio of ACT-PSA/tPSA (0.780) were not significantly different from tPSA (0.663).

CONCLUSION

The ratio fPSA/tPSA showed the best discrimination between BPH and PCa. The single or additional determination of ACT-PSA to tPSA does not improve the differentiation between the two groups of patients.

Molecular forms of prostate-specific antigen and human kallikrein 2 as promising tools for early diagnosis of prostate cancer

Prostate-specific antigen (PSA) is the most useful marker in the early detection of prostate cancer and for the monitoring of patients with this diagnosis. Molecular forms of PSA and also human kallikrein 2 have been used to discriminate between benign prostatic hyperplasia and prostate cancer as well as for the detection of prostate cancer within the gray zone of PSA. In this respect, a literature survey on the diagnostic validity of free PSA (fPSA) related to total PSA (tPSA), PSA bound to alpha1-antichymotrypsin (ACT-PSA), and complexed PSA is given together with our results. The ratio of fPSA:tPSA has been shown to improve the specificity of prostate cancer diagnosis on the basis of tPSA measurements. Unnecessary biopsies can be reduced by about 19-64% in the total PSA range of 4-10 microg/liter while only missing 5-10% of cancers. Furthermore, carcinomas in patients with PSA values <4 microg/liter can be detected, indicating an improved sensitivity because of the percent fPSA at low PSA values. ACT-PSA or complexed PSA alone and the calculated derivatives are not superior in their discriminatory power compared with the percent fPSA. The diagnostic significance of the other molecular PSA forms and human kallikrein 2 needs to be evaluated in more extensive clinical trials.

Laser-induced hyperthermia in rat prostate cancer: role of site of tumor implantation

OBJECTIVES

To investigate the importance of the site of tumor implantation on the treatment response to laser-induced hyperthermia (LIH) of rat prostate cancer (PCa), because interventional manipulations of PCa have been reported to increase metastatic dissemination.

METHODS

Seven to nine days after either subcutaneous or orthotopic implantation of MatLyLu cells, LIH (46.5 degrees C) was induced using pulsed irradiations of a neodymium:yttrium-aluminum-garnet laser. Both local control and distant metastases were evaluated. Plasma metalloproteinase 9 (MMP-9) was tested as a possible marker of PCa progression and LIH response.

RESULTS

Twelve days after LIH treatment of subcutaneous tumors, the volumes were reduced by 64% after 8 minutes of irradiation, 73% after 10 minutes, 81% after 15 minutes, and 91.1% after 20 minutes. In the orthotopic model, the corresponding tumor reductions were 44% after 10 minutes, 61% after 20 minutes, and 65% after 30 minutes. Lung metastases were observed in only 1 animal with subcutaneous tumors. In contrast, 86% of the orthotopic tumor-bearing animals treated for 30 minutes had lung metastases compared with 23% of the untreated tumor-bearing rats. MMP-9 expression was detected in both orthotopic and subcutaneous tumor tissue and in the plasma of tumor-bearing rats. The prostate tissue of healthy rats and subcutaneous tumor-bearing rats was devoid of MMP-9. The plasma levels of MMP-9 showed a trend toward direct correlation with local tumor control but no correlation with the incidence of metastasis.

CONCLUSIONS

These data emphasize the importance of the site of tumor implantation for evaluation of the efficacy of therapeutic interventions and may warrant further studies before widespread clinical application of LIH as monotherapy.

[Molecular forms of prostate-specific antigen and human kallikrein 2 as possible indicators in prostatic carcinoma diagnosis]

Prostate-specific antigen (PSA) is the most useful marker in the early detection of prostate cancer and in the monitoring of patients with this diagnosis. Molecular forms of PSA and human kallikrein 2 (hK2) have been used to discriminate between benign prostatic hyperplasia and prostate cancer, as well as for the detection of prostate cancer within the gray zone of PSA. In this respect, a literature survey on the diagnostic validity of free PSA (fPSA) related to total PSA (tPSA), PSA bound to alpha 1-antichymotrypsin (ACT-PSA), and complexed PSA (cPSA) is given together with our own results. The ratio of fPSA/tPSA has been shown to improve both sensitivity and specificity of prostate cancer diagnosis based on tPSA measurements. The number of biopsies can be reduced in the total PSA range of 4-10 micrograms/l. Furthermore, carcinomas can be detected in patients with PSA values less than 4 micrograms/l. ACT-PSA or cPSA alone and the calculated derivatives are not superior in their discriminatory power compared with tPSA and the fPSA% value. The other molecular PSA forms and hK2 are still objects of research and their diagnostic significance needs to be evaluated in more extensive clinical trials.

Synthetic inhibitor of matrix metalloproteinases (batimastat) reduces prostate cancer growth in an orthotopic rat model

BACKGROUND

Increased concentrations of metalloproteinases are associated with the invasive and metastatic behavior of several human malignant tumors. Normally, enzymatic activity is tightly regulated by nonspecific mechanisms and specific inhibitors. The aim of the study was to determine the potential of a synthetic metalloproteinase inhibitor, batimastat, to show its in vitro effect on MatLyLu cancer cells and its in vivo effect on tumor growth in orthotopic cancer (R3327 Dunning tumor) in rats.

METHODS

In vitro, a dose response curve of batimastat was generated over 4 days using the MTT assay. Prostate cancer was injected in vivo in male Copenhagen rats by inoculating R3327 Dunning tumor cells (MatLyLu) into the ventral prostatic lobe of 30 rats. Each of 10 rats received batimastat (30 mg/kg body weight) or vehicle administered once a day by i.p. application beginning the day of cell inoculation. Ten rats remained untreated. The effect on local tumor growth was evaluated by measuring tumor weights 20 days after tumor cell inoculation.

RESULTS

Significant inhibition of tumor cell proliferation in vitro occurred at 400 and 4,000 ng/ml batimastat. After orthotopic cell inoculation, tumors grew to mean weights of 18.9 g in the control group without treatment, to 22.3 g in the vehicle group, and to 11.1 g in the treated group. In comparison to the control group and to the vehicle group, tumor weights increased significantly less under treatment with batimastat.

CONCLUSIONS

Batimastat is able to reduce tumor growth in the standard prostate cancer model. Using this model, activity against cancer progression of future inhibitory agents can be reliably assessed.

Elimination of serum complexed prostate-specific antigen after radical retropubic prostatectomy

Total prostate-specific antigen (PSA) and complexed PSA were determined in venous blood from 12 patients with prostate cancer before and after radical prostatectomy by using Immuno 1 PSA assays. The elimination kinetics of complexed PSA were compared with that of total PSA. Nearly constant concentrations of complexed PSA were found during the first six hours after surgery, in contrast to the rapid elimination of free PSA and the significant decrease of total PSA. From day one to ten there was a continuous and nearly identical decrease of complexed PSA compared to total PSA. Our findings suggest that the initial rapid decrease of free PSA immediately after operation could be caused by formation of new PSA-complex.

ACT-PSA and complexed PSA elimination kinetics in serum after radical retropubic prostatectomy: proof of new complex forming of PSA after release into circulation

OBJECTIVES

To study the elimination kinetics of alpha(1)-antichymotrypsin (ACT)-prostate-specific antigen (PSA) and complexed PSA (cPSA) in comparison to the biexponential decrease of total PSA and free PSA after radical prostatectomy.

METHODS

Serum total PSA, free PSA, ACT-PSA, and cPSA values and the corresponding ratios were determined in venous blood from 12 patients with prostate cancer. The samples were taken before surgery, immediately after surgery, 1, 2, 3, 4, 5, and 6 hours after surgery, and then once daily for the next 10 days. Total PSA and cPSA were analyzed by using Immuno 1 PSA assays (Bayer Corporation); free PSA was measured using the AxSym test kit (Abbott Diagnostics). For ACT-PSA, the ES analyzer system was used (Roche Diagnostics). Statistical calculations were performed with the analysis of variance and Wilcoxon tests.

RESULTS

During the first 6 hours after radical retropubic prostatectomy, we found nearly constant levels of ACT-PSA and cPSA, in contrast to the rapid elimination of free PSA and significant decrease in total PSA. From days 1 to 10, a continuous and nearly identical decrease of ACT-PSA and cPSA occurred compared with total PSA; free PSA was eliminated more rapidly.

CONCLUSIONS

In addition to the opinion that the first PSA decrease might be an effect of the operation itself or caused by renal elimination alone, our findings indicate that the initial rapid decrease of free PSA immediately after surgery could be caused by new complex forming of PSA with ACT and other serum protease inhibitors.

Matrix-metalloproteinases and their inhibitors in plasma and tumor tissue of patients with renal cell carcinoma

Matrix-metalloproteinases (MMPs) are associated with invasive and metastatic behavior of several human malignant tumors. We have determined MMP-2 and MMP-9 and tissue inhibitors of MMPs (TIMP-1 and TIMP-2) in blood plasma and in renal tissue samples of patients with renal cell carcinoma (RCC) from cancerous and non-cancerous parts of the same kidney. In tumor tissue, MMP-9 and TIMP-1 were significantly higher than in normal counterparts. MMP-2 was not different between tumor tissue and normal counterparts. TIMP-2 values could not be measured. In plasma, MMP-9 concentrations were significantly higher in RCC patients than in healthy controls, MMP-2 and TIMP-2 concentrations were higher in healthy controls and TIMP-1 concentrations were not different.

Molecular forms of prostate-specific antigen in malignant and benign prostatic tissue: biochemical and diagnostic implications

BACKGROUND

Patients with prostate cancer (PCa) show a lower ratio of free prostate-specific antigen (fPSA) to total PSA (tPSA) in serum than patients with benign prostatic hyperplasia (BPH). The patterns of the intracellular PSA isoforms in malignant and benign prostatic tissue have been studied as potential molecular reasons for this phenomenon.

METHODS

Prostatic tissue samples were obtained after cystoprostatectomy from patients with bladder cancer (n = 10), from BPH patients (transurethral resection of the prostate, n = 10; adenomectomy, n = 10), and from the cancerous and noncancerous parts of the same prostates removed surgically by prostatectomy because of PCa (n = 20). PSA pattern was characterized by gel filtration, immunoblotting, and immunoassays for tPSA, fPSA, alpha(1)-antichymotrypsin-PSA (ACT-PSA), and complexed PSA (Bayer Immuno 1 assay). Comparisons were made with the PSA concentrations in serum.

RESULTS

The major portion of tPSA in all tissue samples was fPSA; complexed PSA forms were <2%. Samples from cystoprostatectomy patients had the lowest and those from adenomectomy patients the highest values of tPSA and fPSA. PSA concentrations were lower in cancerous than in the noncancerous parts of the prostate. No significant correlations were found between tumor stage or grade and the amounts of tPSA, fPSA, and ACT-PSA in tissue. Tissue PSA values were not correlated with the serum PSA concentrations nor with the ratios fPSA/tPSA and ACT-PSA/tPSA in sera.

CONCLUSIONS

The amounts of tPSA and the PSA isoforms in prostatic tissue explain neither the concentrations of tPSA and PSA isoforms in serum nor the behavior of the ratio fPSA/tPSA in patients with BPH and PCa.

Ratio of free or complexed prostate-specific antigen (PSA) to total PSA: which ratio improves differentiation between benign prostatic hyperplasia and prostate cancer?

BACKGROUND

The aim of this study was to compare the diagnostic utility of a new assay that measures all forms of prostate-specific antigen complexed (cPSA) to serum proteins except alpha(2)-macroglobulin with the assay of free PSA (fPSA) and the corresponding ratios to total PSA (tPSA) to improve the differentiation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa).

METHODS

Serum samples were collected from 91 men without prostate disease and with normal digital rectal examination (controls), 144 untreated patients with PCa, and 89 patients with BPH. tPSA and cPSA were measured using the Bayer Immuno 1 system; fPSA and the additional tPSA were measured with the Roche Elecsys system.

RESULTS

The median cPSA/tPSA, fPSA/tPSA, and fPSA/cPSA ratios were significantly different between patients with BPH and PCa (78.7% vs 90.7%, 25.5% vs 12.1%, and 36.8% vs 14.3%, respectively; P <0.001). No correlations of cPSA and its ratios to tumor stage and grade were found. ROC analysis showed that cPSA was not different from tPSA (areas under the curve, 0.632 vs 0.568), whereas the cPSA/tPSA ratio was similar to the fPSA/tPSA ratio in increasing discrimination between BPH and PCa patients with tPSA concentrations in the tPSA gray zone between 2 and 10 microg/L (areas under the curve, 0.851 vs 0.838).

CONCLUSIONS

Compared with tPSA, the fPSA/tPSA and cPSA/tPSA ratios both improve the differentiation between BPH and PCa comparably and are similarly effective in reducing the rate of unnecessary biopsies, whereas cPSA alone does not have any effect.

Determination of alpha1-antichymotrypsin-PSA complex in serum does not improve the differentiation between benign prostatic hyperplasia and prostate cancer compared with total PSA and percent free PSA

OBJECTIVES

To evaluate the analytical performance and diagnostic utility of alpha1-antichymotrypsin (ACT)-prostate-specific antigen (PSA) complex in serum to improve the differentiation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa).

METHODS

Serum concentrations of total PSA (tPSA), free PSA (fPSA), and ACT-PSA were measured in 112 untreated patients with PCa (median age 65 years), 34 patients with BPH (median age 66 years) with histologic confirmation, and 33 men without prostate disease and with a normal digital rectal examination considered as controls (median age 54 years). Sera were frozen at -80 degrees C within 2 hours after collection and then analyzed during a 12-week period. Determinations were made with the Enzymun-Test for tPSA and fPSA and with a prototype assay for ACT-PSA on the ES system (Roche Diagnostics, Boehringer Mannheim).

RESULTS

The new ACT-PSA assay showed reliable data of analytical performance. The lower detection limit amounted to 0.068 microg/L. The assay was linear to 50 microg/L. Spiking experiments showed a mean recovery rate of 98.2%. No interferences of the assay were observed in patients with acute inflammation and highly increased ACT concentrations. The values of intra- and interassay imprecision ranged from 1.51% to 3.48% and 2.1% to 6.3%, respectively. The median value of ACT-PSA concentrations were significantly different (P <0.001) between controls and patients with BPH and PCa (0.40, 3.86, 5.26 microg/L, respectively). The median fPSA/tPSA and fPSA/ACT-PSA ratios were significantly different between BPH and PCa (24.3% versus 12.2%, P <0.001 and 32.9% versus 15.0%, P <0.001, respectively), but no difference of the ACT-PSA/tPSA ratio was observed (78.2% versus 78.7%, P = 0.696). Receiver operating characteristics of ACT-PSA (area under the curve = 0.630) and all the derivative ratios of fPSA/ACT-PSA (area = 0.737) and ACT-PSA/tPSA (area = 0.528) were not different from that of tPSA (area = 0.619), but showed a lower discrimination power between BPH and PCa than the fPSA/tPSA ratio (area = 0.790).

CONCLUSIONS

Using this prototype assay to quantify ACT-PSA in serum, we have demonstrated that ACT-PSA and the calculated derivatives are not superior in the differentiation between BPH and PCa compared with tPSA and the ratio of fPSA to tPSA.

Near-infrared confocal laser scanning microscopy of bladder tissue in vivo

OBJECTIVES

To assess the potential of a near-infrared confocal laser scanning microscope (CLSM) for imaging bladder tissue in vivo.

METHODS

Confocal images of the exposed bladder of male Sprague-Dawley rats were obtained with a CLSM. To minimize tissue motion, the bladder was placed in light contact under an objective lens housing, and the top surface was lightly flattened with a coverslip. Images were obtained from the outer and inner layers of the bladder wall with a lateral resolution of 0.5 to 1 microm and an axial resolution (section thickness) of 3 to 5 microm. The confocal images were later correlated with routine histologic studies.

RESULTS

The CLSM allows imaging of the urothelium, the superficial and deep portions of the lamina propria, the muscularis propria, and the serosa of the bladder wall in vivo. Urothelial cells, collagen bundles and fibers, muscle, and circulating blood cells in capillaries and larger blood vessels are easily visualized. The confocal images correlated well with the histologic studies.

CONCLUSIONS

Confocal microscopy allows real-time, high-resolution, high-contrast imaging of cellular and structural morphologic features to a maximal depth of 300 microm within the bladder wall in vivo. Artifacts caused by tissue motion can be minimized with a bladder-objective lens contact housing.