Search PubMed⌕ Search

Biomedical subjects

M Lein

Publications and source records attributed to M Lein.

At least 55 records · Page 3Linked to original sources
PubMed1999

Rapid detection of elevated prostate-specific antigen levels in blood: performance of various membrane strip tests compared.

OBJECTIVES: To compare the ability of four commercially available membrane strip tests to detect increased (4 microg/L or more) concentrations of prostate-specific antigen (PSA) in blood. METHODS: Serum samples with PSA concentrations less than 4 microg/L (n = 67) and from greater than 4 microg/L to 20 microg/L (n = 32) were independently examined by two observers using the PSA membrane strip tests from Chembio, Medpro, Seratec, and Syntron. The positive and negative results of each membrane strip test were classified as either true positive or negative and false negative or positive by comparing them with the quantitative PSA assay of Immulite DPC using the conventional threshold value of 4 microg/L. RESULTS: The interobserver variations of the tests were between 93% and 97%. The color stability of the Seratec and Chembio tests did not show significant differences between test results read within 10 to 20 minutes of the reaction time; however, the results of the other two tests were especially affected by variations in the reading time. The sensitivity and specificity of the tests in relation to the threshold of 4 microg/L were 67% to 93% and 87% to 97%, respectively. CONCLUSIONS: The Syntron test and, within certain limitations, the Seratec test fulfill the concept of a rapid and convenient PSA determination to detect PSA concentrations greater than 4 microg/L. Methodologic optimization of the tests by a grading of the PSA measuring ranges (eg, between 0 and 2, 3 and 4, 4 and 6, and 7 and 10 microg/L) should be taken into account for future development.

Aged↗
PubMed1999

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.

Animals↗
PubMed1999

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.

Adult↗
PubMed1999

Cathepsins B, H, L and cysteine protease inhibitors in malignant prostate cell lines, primary cultured prostatic cells and prostatic tissue.

Elevated activities of cysteine proteinases, the cathepsins B, H, L (CB, CH, CL) and diminished cysteine protease inhibitors (CPI) have been demonstrated in a variety of tumours and have been suggested to contribute to invasion and metastasis. The situation for prostate cancer is still unknown. In this study, using fluorimetric assays, the catalytic activities of CB, CH, CL were measured in prostatic tissue samples after radical prostatectomy, adenomectomy, transurethral resection of the prostate, in cell cultures grown from cancerous and non-cancerous parts of human prostate after prostatectomy and in the cell lines LNCaP, DU 145 and PC 3. CPIs were determined using heat activation before testing their inhibitory activity against purified CB. Comparing matched pairs of normal and cancerous tissue samples from the prostate, significantly decreased levels of CB, CL in malignant parts of the prostate were found. In contrast, primary cell cultures from cancerous samples showed elevated levels of CB, CH, CL and increased ratios of cathepsins to CPI compared with cell cultures from normal prostate. Established cell lines showed a similar distribution pattern of each cathepsin, DU 145 containing the highest levels, followed by LNCaP and PC 3. Our results suggest that elevated cathepsin levels and consequently increased ratios of cathepsins to CPI in primary cell cultures from cancerous versus non-cancerous parts of the prostate may be indicative of a cellular proteolytic imbalance in prostatic cancer cells. In this respect, primary cell culture experiments should be preferred to determinations in tissue samples.

Adult↗
PubMed1998

Quantification of matrix metalloproteinases and tissue inhibitors of metalloproteinase in prostatic tissue: analytical aspects.

BACKGROUND: The balance between matrix metalloproteinases (MMP) and the tissue inhibitors of metalloproteinases (TIMP) has been seen as important during tumor invasion and progression. The determination of these components needs a special strategy of tissue preparation. This analytical problem has not been considered for prostatic tissue. METHODS: We adapted an extraction method consisting of two extraction steps with 0.25% Triton X-100/CaCl2 solution and two heat extraction steps at 60 degrees C for 4 min. This combination allowed a complete extraction of MMP (measured as enzyme activity) and TIMP-1 (measured with an ELISA test) from cancerous and normal prostatic tissue samples. RESULTS: The median values for cancerous vs. normal MMPs (50.8 mU/g wet tissue and 1,580 mU/g protein vs. 88.8 and 2,497) and TIMP-1 (4.49 micrograms/g wet tissue and 96.7 micrograms/g protein vs. 12.4 and 237.8) were significantly lower, whereas the respective ratios for MMP/ TIMP-1 (11.1 vs. 4.0 on wet weight and 15.5 vs. 5.3 on protein basis) were significantly higher. CONCLUSIONS: An optimized extraction procedure was elaborated for determining MMPs and TIMP-1 in prostatic tissue samples. The increased ratio of MMP/TIMP-1 can be interpreted as an indicator of the imbalance between MMP and TIMP, characteristic of prostate carcinoma tissue.

Enzyme-Linked Immunosorbent Assay↗
PubMed1998

[Metalloproteinases (MMP-1, MMP-3) and their inhibitors (TIMP) in blood plasma of patients with prostate carcinoma].

Matrix metalloproteinases (MMP) and their tissue inhibitors (TIMP) are involved in important processes of tumor invasion and metastasis. In the study presented, matrix metalloproteinase 1 (MMP1) and 3 (MMP3), the tissue inhibitor of metalloproteinase 1 (TIMP1) and the complex MMP1/TIMP1 were measured by ELISA tests specific for these proteins in blood plasma. These components have been investigated in prostate cancer patients (PCa) with metastases (n = 18; T2, 3, 4 pN1, 2M1), prostate cancer patients without metastases (n = 29; T2, 3 pNOMO), patients with benign prostate hyperplasia (BPH; n = 29) and in healthy men (n = 35). Mean values of MMP1 and of the complex MMP1/TIMP1 were not different among the four groups. The mean values of MMP3 and especially TIMP1 were significantly higher in prostate cancer patients with metastases compared with controls, BPH patients and prostate cancer patients without metastases. Ten of these 18 patients had TIMP1 levels higher than the upper reference limit. TIMP1 concentrations correlate to the tumor stage but not to the tumor grade. These results indicate, that TIMP1 could be an potential marker for metastases in prostate cancer patients.

Aged↗
PubMed1998

The percentage of free prostate specific antigen is an age-independent tumour marker for prostate cancer: establishment of reference ranges in a large population of healthy men.

OBJECTIVE: To define the reference range for the ratio of free to total prostate-specific antigen (fPSA%) in a population of healthy men with no clinically evident prostate cancer and to assess the influence of age on this tumour marker, thus determining the utility of fPSA% in enhancing the discriminatory power of PSA to differentiate healthy men and patients with benign prostatic hyperplasia from those with prostate cancer. SUBJECTS AND METHODS: In a prospective cohort study between May and August 1996, 1160 white men aged 20-89 years (957 were 40-69 years old, 82% of all subjects) from nine European and eight non-European countries were assessed. None of the participants who had a history of prostate cancer had undergone prostatectomy. A standard clinical examination including a digital rectal examination was performed to exclude the presence of prostate cancer. Transrectal ultrasonography was not an inclusion criterion, as it was not available in every case. Total PSA (tPSA) and free PSA (fPSA) were determined in 61 laboratories using the appropriate Enzymun-Test for tPSA and fPSA (Boehringer Mannheim Diagnostics, Mannheim, Germany). Serum tPSA, fPSA and fPSA% were then assessed as a function of the subjects' age. RESULTS: The serum tPSA and fPSA were significantly different among age decades 2-8 (P < 0.001), with increasing median values, indicating that both variables depend on age. The recommended upper reference limit (95th percentile) for tPSA is 1.78 ng/mL for men aged 30-39 years, 1.75 ng/mL for 40-49 years, 2.27 ng/mL for 50-59 years, 3.48 ng/mL for 60-69 years and 4.26 ng/mL for 70-79 years. The fPSA% was not significantly different between decades 3-8 (P = 0.06). Those aged 20-29 years had a slightly higher median value (P = 0.03) than the other age groups. The recommended lower reference limit (fifth percentile) for fPSA% is 12.6%. CONCLUSION: The fPSA% for clinically relevant age groups in healthy men was independent of age, which simplifies the use and interpretation of this relatively new tumour marker.

Adult↗
PubMed1998

Ratio of free-to-total prostate specific antigen in serum cannot distinguish patients with prostate cancer from those with chronic inflammation of the prostate.

PURPOSE: We demonstrate the effect of chronic inflammation of the prostate on the ratio of free-to-total prostate specific antigen (PSA) in serum calculated as a percentage of free PSA and, therefore, that percentage of free PSA is an unspecific means to distinguish among prostate cancer, chronic prostatitis and benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: Total, free and percentage of free PSA was measured in 66 men with prostate cancer, 119 with BPH and 17 with asymptomatic chronic prostatitis. In all patients the diagnosis was histopathologically confirmed by microscopic examination of prostatic specimens after sextant biopsy, transurethral prostatic resection or prostatectomy. RESULTS: The median values of total, free and percentage of free PSA were 4.11 microg./l., 0.75 microg./l. and 20.4% in patients with BPH, 10.0 microg./l., 0.84 microg./l. and 8.5% in those with prostate cancer, and 7.60 microg./l., 1.23 microg./l. and 10.6% in those with chronic prostatitis. Patients with prostate cancer and chronic prostatitis had a significantly lower percentage of free PSA than those with BPH. Receiver operating characteristics curve analysis showed that percentage of free PSA as a discriminator between prostate cancer and BPH was not suitable for differentiating between prostate cancer and chronic prostatitis. CONCLUSIONS: Chronic prostatitis is not characterized by elevated total PSA concentrations alone but also by a decreased percentage of free PSA, a tendency similar to that in prostate cancer. This unspecific change in percentage of free PSA must be considered to interpret the percentage of free PSA correctly.

Aged↗
PubMed1998

Relation of free PSA/total PSA in serum for differentiating between patients with prostatic cancer and benign hyperplasia of the prostate: which cutoff should be used?

A review on literature data is given concerning free prostate-specific antigen (f-PSA) and the corresponding cutoffs of f-PSA/t-PSA for differentiating patients with cancer of the prostate from those with benign prostatic hyperplasia. The special importance of the diagnostic criterion (sensitivity, specificity, efficiency) for establishing the cutoff is demonstrated. On the basis of our own data, the application of the f-PSA% is recommended as an additional decision criterion for biopsy.

Biopsy↗
PubMed1997

Factors influencing the ratio of free to total prostate-specific antigen in serum.

The ratio of free prostate-specific antigen (f-PSA) to total PSA (t-PSA) in serum, calculated as percent free PSA (f-PSA%), is lower in patients with prostate carcinoma (PCa) than in patients with benign prostate hyperplasia (BPH). This parameter facilitates discrimination between the 2 groups of patients, but there is an overlapping of data. A better understanding of factors influencing this ratio is of practical importance. Therefore, f-PSA% was measured in controls and patients suffering from BPH, PCa and chronic prostatic inflammation with t-PSA concentrations up to 20 microg/l using the IMMULITE assays. The relationships of f-PSA% to clinical situation, age, prostate volume, kind of treatment, and stage and grade of tumor were calculated. Compared with controls or BPH patients, mean f-PSA% values were reduced in PCa patients and in patients with chronic prostatic inflammation. The prostate volume was the most important factor to influence f-PSA%. The difference of f-PSA% between PCa and BPH patients with prostate volumes smaller than 40 cm3 was lost if the prostate volumes exceeded 40 cm3. No relationship of f-PSA% to pTNM stage or grade of tumor was observed. In contrast to t-PSA concentrations, the f-PSA% values were not age-dependent and were not influenced by any kind of treatment in BPH and PCa patients either, which simplifies the use of f-PSA% compared with t-PSA. Thus, for using f-PSA% in clinical practice and for interpreting the data correctly, the advantages shown have to be considered along with the potential limitations of f-PSA%.

Adult↗
PubMed1997

Matrix metalloproteinases 1 and 3, tissue inhibitor of metalloproteinase-1 and the complex of metalloproteinase-1/tissue inhibitor in plasma of patients with prostate cancer.

We analyzed blood plasma concentrations of matrix metalloproteinase-1 and -3 (MMP-1; MMP-3), the tissue inhibitor of metalloproteinase-1 (TIMP-1) and the complex MMP-1/TIMP-1, and looked for any correlation with prostate cancer stage. These components were measured by ELISA tests specific for these proteins in healthy male controls (n = 35), and in patients with benign prostatic hyperplasia (BPH; n = 29), with prostate cancer (PCa) without metastasis (T2,3pN0M0; n = 29) and with PCa with metastatic disease (T2,3,4pN1,2M1; n = 18). Mean values of MMP-1 and of the complex MMP-1/TIMP-1 were not different among the 4 groups studied. The mean MMP-3 and especially TIMP-1 concentrations were significantly higher in PCa patients with metastases compared with controls, BPH and PCa patients without metastases. Ten of these 18 patients had TIMP-1 concentrations higher than the upper reference limit. TIMP-1 concentrations were correlated with staging but not with grading. Our results point towards plasma TIMP-1 concentration as a potential marker of malignant progression of PCa.

Adult↗
PubMed1997

Increased analytical sensitivity of RT-PCR of PSA mRNA decreases diagnostic specificity of detection of prostatic cells in blood.

The diagnostic specificity of the detection of disseminated prostatic cells by reverse-transcriptase polymerase chain reaction (RT-PCR) of PSA mRNA was investigated. A sensitive nested PCR was developed. In blood samples from 10 healthy female and 10 healthy male persons examined by RT-PCR, mRNA of PSA was detected 3 times in each group. In the groups of patients suffering from benign prostate hyperplasia and prostate cancer, 6 of 11 and 5 of 12, respectively, gave positive RT-PCR results. With increasing analytical sensitivity of the RT-PCR of PSA mRNA, the diagnostic specificity of the assay is decreased. Further development of this diagnostic method requires the introduction of the quantitative PCR which may make possible discrimination between prostatic and non-prostatic source of PSA mRNA by quantification.

Female↗
PubMed1997

The influence of prostate volume on the ratio of free to total prostate specific antigen in serum of patients with prostate carcinoma and benign prostate hyperplasia.

BACKGROUND: Determining the ratio of free to total prostate specific antigen (f-PSA to t-PSA, calculated as the percentage of f-PSA [f-PSA%]) in serum allow for a clearer distinction between patients with prostate carcinoma (PCa) and patients with benign prostate hyperplasia (BPH) than determining the level of t-PSA alone. To find influencing factors on f-PSA%, the authors investigated prostate volume, TNM classification, and tumor stage. METHODS: The authors measured f-PSA and t-PSA in 36 men with untreated PCa (tumor classification: T1, 2, 3pNO, MO), 44 patients with BPH, and 54 healthy controls. Prostate volume was determined by transrectal ultrasound. RESULTS: The median values of t-PSA and f-PSA% were 7.8 micrograms/L and 10.5% in PCa patients, 4.3 micrograms/L and 20.8% in patients with BPH, and 1.4 micrograms/L and 23.6% in the control group. Patients with PCa had a significantly lower proportion of f-PSA than BPH patients and healthy men. There was no correlation of f-PSA% to TNM stage or tumor grade. In PCa patients a significant positive correlation (correlation coefficient [r] = 0.51, P < 0.001) was found between f-PSA% and prostate volume, whereas there was no significant correlation in BPH patients (r = -0.27, P > 0.05). There was a significant difference in f-PSA% between PCa and BPH patients with prostate volumes smaller than 40 cm3 (9.0% vs. 21.6%, P < 0.01) but not between patients in these 2 groups with prostate volumes exceeding 40 cm3 (15.1% vs. 18.2%, P = 0.11). CONCLUSIONS: Determining the ratio of f-PSA to t-PSA to discriminate between PCa and BPH patients yields significant results only in men with a prostate volume of less than 40 cm3.

Aged↗
PubMed1997

Analytical aspects regarding the measurement of metalloproteinases and their inhibitors in blood.

OBJECTIVE: Both in vitro and in vivo investigations have shown that the balance between matrix metalloproteinases (MMP) and the tissue inhibitors of metalloproteinases (TIMP) seems to be important in physiological and pathological processes which involve tissue remodeling and repair. DESIGN AND METHODS: In order to investigate the analytical reliability of new commercial ELISA tests. BIOTRAK test kits (Amersham Int.) were used for the determination of metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1), and the MMP-1/TIMP-1 complex in blood. RESULTS: The detection limits and the precision data were in the usual ranges of ELISA tests so that concentrations found in blood could be determined reliably. Since all three analytes were lower in heparin plasma than in serum or EDTA plasma, heparin plasma was selected as the specimen of choice. Measurement of diluted samples gave higher values than those of undiluted native plasma samples because the inhibitory effects of specific/unspecific inhibitors or other matrix components were apparently reduced. To obtain comparable data from different laboratories, the predilution of samples must be defined. We recommend to use diluted plasma samples of 1:5, 1:21, and 1:11 for the determination of MMP-1, TIMP-1, and the complex MMP-1/TIMP1, respectively. The preliminary upper 95% reference limits measured under these conditions in healthy subjects (40 females: 40 males) were 14.4 micrograms/L for MMP-1 in females, 20 micrograms/L for MMP-1 in males. 1668 micrograms/L for TIMP-1 and 116 micrograms/L for the complex MMP-1/TIMP-1. CONCLUSION: The study has shown that the BIOTRAK test combinations for MMP-1, TIMP-1, and MMP-1/TIMP-1 complex allow a reliable measurement of the analyte concentrations in heparin plasma. In order to avoid preanalytical misinterpretations only heparin plasma samples in defined dilutions should be used.

Adult↗