Monitoring percent free PSA in serial specimens: improvement of test specificity, early detection, and identification of occult tumors

We have measured the serum concentration of prostate specific antigen (tPSA) and determined the percent free PSA (% fPSA) in serial specimens from 64 patients with prostate cancer, 35 patients with benign prostate hyperplasia (BPH), and 3 patients with prostitis. We found that the % fPSAs were not a constant for individual patients during the course of the disease. When we compared only the % fPSA of the first specimen of serial specimens from individual patients, who were largely untreated, 37% of BPH specimens were above 22%, whereas only 1.6% cancer samples were above that value. We also found that 67% of cancer specimens and 14% of BPH samples were below 8%, respectively. Although % fPSA distribution pattern remained similar between two types of specimens, less differentiation was found between BPH and prostate cancer in random specimens compared to the study using first specimens of an individual patient's serial samples. Percent fPSA apparently are affected by treatment. However, the most important benefit for the determination of % fPSA appears to be the sensitivity of % fPSA to identify occult tumors when the tPSAs were in the normal concentration range. Determination of % fPSA also seems to improve the specificity of tPSA, not only during screening for the differentiation between BPH and prostate cancer, but also during monitoring of treatment and recurrence.

Serum chromogranin A: early detection of hormonal resistance in prostate cancer patients

We monitored both chromogranin A (CgA) and neuron specific enolase (NSE) in serial serum specimens from 14 patients with prostate cancer (CAP patients) showing resistance to hormonal treatment. Elevated serum CgA was detected in 10 out of these 14 patients (71%) during treatment, and an early appearance of elevated serum CgA was found in 6 of 14 (43%) of these patients when serum tPSA levels were still in the normal range. If patients with radical prostatectomy were not included, the percentage of patients showing an early appearance of elevated serum CgA would have been much higher. Elevated serum CgA levels also were found in patients not subject to hormonal therapy. Serial specimens from two out of three prostate cancer patients, randomly selected, contained elevated serum CgA. Serum NSE was not detectable in any of the serial specimens we studied, suggesting that CgA, not NSE, should be used as a marker for neuroendocrine differentiation. We also compared the serum CgA in random serum specimens between patients with BPH (benign prostate hyperplasia) and with prostate cancer in the concentration range of serum tPSA between 3-15 ng/mL. Although serum CgA concentrations in BPH patients overlapped considerably with those levels in patients with prostate cancer, levels > 100 ng/mL should suggest prostate cancer. The early appearance of elevated serum CgA allows an early change of therapy to be made and can lead to the effective prevention of any further development of metastases.

Production of milligram concentrations of free prostate specific antigen (fPSA) from LNCaP cell culture: difference between fPSA from LNCaP cell and seminal plasma

We have established a procedure for the production of milligrams of free PSA (fPSA) from LNCaP cells derived from a human carcinoma of the prostate. By growing LNCaP cells in a serum-free medium in the presence of a synthetic androgen (R1881) and taking advantage of the special design of the Micro-mouse Hollow Fiber Bioreactor, relatively pure fPSA could be obtained. We found that columns containing either Sephacryl S-100 or S-200 could be used to remove the small amount of bovine serum albumin (BSA) and PSA-alpha 1-antichymotrypsin complex (PSA-ACT) from the preparation. More than 90% of the PSA from LNCaP cell cultures are fPSA. Like fPSA from seminal plasma, two fractions of fPSA differing in protease activity can be separated by DEAE-Sepharose chromatography. Based on the band pattern exhibited on the Western blot following sodium dodecyl sulfate-polyacrylamide electrophoresis separation, fPSA from LNCaP contains more inactive PSA isoforms. This was confirmed by chromatofocusing: the isoelectric point (pl) of the major PSA isoforms from the LNCaP cell culture were higher (6.8 and 6.6) than that (6.4 and 6.1) of fPSA from seminal fluid. We conclude that the LNCaP cell culture is a reliable source for obtaining large quantities of pure fPSA both for the preparation of assay calibrators and controls and for studying the difference in fPSA between benign prostate disease and prostate cancer.

Elevated serum chromogranin A is detectable in patients with carcinomas at advanced disease stages

Chromogranin A (CgA), a marker of neuroendocrine cells and an indicator for neuroendocrine differentiation, is associated with a poor prognosis when detected in tumor tissue, based on immunohistochemical techniques. We sought to determine whether it is possible to detect elevated serum CgA in patients with commonly occurring carcinomas of non-neuroendocrine origin. CgA was measured in both random and serial serum specimens, using a serum CgA assay developed in our laboratory. Elevated levels of serum CgA were detected in patients with carcinoma of the prostate, breast, ovary, pancreas, and colon. Serum CgA levels in patients with all types of carcinoma appeared to parallel the changes of serum dominant tumor markers and were found in sera containing highly elevated tumor markers. Based on these preliminary findings, perhaps we should monitor CgA, in addition to the routinely used tumor markers, during the treatment of patients with carcinomas to determine if CgA is useful as a prognostic marker in carcinomas other than prostatic cancer.

Heritability of prostate-specific antigen and relationship with zonal prostate volumes in aging twins

Both benign prostatic hyperplasia and prostate-specific antigen (PSA) have been shown to increase with age and with prostate volume in men, but the influence of heredity on these relationships is not completely understood. This study has two aims: 1) to investigate the inter-relationships of age, PSA, and various zonal measurements in the prostate; and 2) to assess the impact of heritable influences on total PSA. Eighty-four monozygotic twin pairs and 83 dizygotic twin pairs were studied, and serum total PSA, free PSA, and PSA-alpha1-antichymotrypsin were measured. Their prostate volumes [total (TV), transition zone (TZ), and peripheral zone) were quantitated using transrectal ultrasound. Total PSA is significantly correlated with all zonal prostate measurements (TZ, peripheral zone, TV, and TZ/TV) and with age. When linear regression was applied, only age and TZ were retained in the final model. The proportion of variability in total PSA explained by these two factors, however, is below 24%. In contrast, estimates of heritability show that approximately 45% of the variability in total PSA can be explained by inherited factors. Whereas age and TZ are linearly related to total PSA, their influence is much less than that of familial and genetic factors. It is uncertain whether these factors predispose also to prostate cancer or if they are independent of those, whether they confound the accuracy of using total serum PSA level as a diagnostic tool.

Development of a microplate assay for serum chromogranin A (CgA): establishment of normal reference values and detection of elevated CgA in malignant diseases

Chromogranin A (CgA), a marker for neuroendocrine cells, is associated with poor prognosis when detected by immunohistochemical technique in prostate tumors. We have developed an ELISA on microplates for serum CgA and established the normal reference range. We also attempted to find out whether elevated serum CgA levels could be found in patients with various malignant diseases. Because of non-Gaussian distribution, both medians and 97.5 percentiles of serum CgA levels for men and women of four different age groups were determined. For women, the median and 97.5 percentiles are 20.7 and 63.9 ng/mL for ages 20 to 50, and 32 and 93.8 for 50 to 80 years of age, respectively; for men, they are 27.9 and 78.4 ng/mL for ages 18 to 40 and 41.6 and 92 for 40 to 80 years old, respectively. Elevated serum concentrations of CgA were detectable in patients with prostate cancer not undergoing hormonal treatment, and in patients with various malignant diseases including nonendocrine carcinomas. Most elevated serum CgA levels were associated with sera containing highly elevated serum tumor markers. Drugs targeting neuroendocrine cells should be administered for cancer patients with elevated serum CgA levels.

Direct plasma sample injection in multiple-component LC-MS-MS assays for high-throughput pharmacokinetic screening

The simultaneous dosing of numerous compounds followed by multiple-component analysis using LC-MS-MS (the N-in-1 approach) has significantly improved the throughput of the drug-screening process. However, plasma samples still need to be extracted before LC-MS-MS analysis, which frequently limits the throughput of the assay. In this work, a high-throughput on-line extraction technique has been developed for multiple-component LC-MS-MS assays using a high-flow column-switching technique. In N-in-1 LC-MS-MS assays, high sensitivity is required since the dose level is generally reduced to minimize drug-drug interactions. In addition, good chromatographic separation is essential to minimize interference and suppression effects. The direct plasma sample injection method developed in this work has successfully met the two requirements for multiple-component LC-MS-MS assays in high-throughput pharmacokinetic screening. Plasma samples containing a large number of potential drug candidates were directly injected onto an extraction column operated under a flow rate sufficiently high to exhibit a turbulent-flow profile. The extracted analytes were then eluted onto an analytical column via column switching for LC-MS-MS analysis. The use of turbulent flow resulted in a faster and more rugged extraction with reduced carryover compared with results obtained under laminar-flow conditions. Meanwhile, the use of a column-switching method maintained the chromatographic resolving power and high sensitivity of the LC-MS-MS assay. Separation efficiency, dynamic range, accuracy, and precision comparable with those of solid-phase extraction have been achieved with the turbulent-flow column-switching technique. As a result, this technique has been successfully and routinely used for high-throughput pharmacokinetic screening.

Quantification of HER2 oncoprotein in fine-needle aspirates of the breast

Measurements of either HER2 gene overexpression or its gene-coded protein (p185) are clinically useful for predicting prognosis in breast cancer. The measurements are also useful for identifying metastatic breast cancer patients who may benefit from Herceptin treatment. Since fine needle aspiration (FNA) of the breast has become an increasingly popular technique for obtaining tissue specimens, we have developed a sensitive method to quantify p185 in the aspirate. For this procedure, p185 from the cell pellet of FNA is extracted with a buffer containing Triton X-100, and the p185 is measured with an enzyme immunoassay. Most of the malignant breast tumors (N=7) in this study were associated with elevated p185 concentrations (6/7, 319+/-222 U/mg), compared to the p185 concentrations in normal breast tissue (42.8+/-35 U/mg, N=47) or benign lesions (43.1+/-20.2 U/mg, N=22). Quantification of p185 in FNA may improve the assessment of breast cancer patients, revealing whether they are at high risk and may benefit from Herceptin treatment.

Different patterns of serum chromogranin A in patients with prostate cancer with and without undergoing hormonal therapy

Elevated serum chromogranin A (CgA) levels have been detected in patients with prostate cancer who have developed resistance to hormonal therapy. We would like to reexamine these cases by using serial specimens to determine whether such elevated levels are also detectable in prostate cancer patients not undergoing hormonal therapy. Serum CgA was measured in both random and serial specimens from prostate cancer patients with and without undergoing hormonal therapy. We found that serum CgA levels became elevated much earlier than did the levels of serum PSA in approximately one-third of prostate cancer patients developing resistance to hormonal therapy. On the other hand, serum CgA levels became elevated at later, more advanced stages of the disease in patients not undergoing hormonal therapy. Elevated serum CgA levels were usually detected in specimens containing highly elevated PSA. The early rise of serum CgA levels provides an early signal allowing a change of therapy to be made before the disease progresses to a fatal stage. Drugs targeting neuroendocrine cells should be considered for prostate cancer patients with elevated serum CgA levels.

Management of severe flap wrinkling or dislodgment after laser in situ keratomileusis

PURPOSE

To review the management and results of cases with severe flap wrinkling or dislodgment after laser in situ keratomileusis (LASIK).

SETTING

University Eye Center, Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, The Chinese University of Hong Kong.

METHODS

Four patients with severe flap wrinkling or dislodgment after LASIK are described. Surgical repositioning of the flap was performed in all cases. Flap status, refractive changes, and final uncorrected and best corrected visual acuities were used to evaluate the outcome of flap repositioning.

RESULTS

Flap repositioning required suturing in 2 patients, 1 of whom developed severe epithelial ingrowth with melting of the corneal flap and stromal bed and eventually required flap removal. The stromal inflammation resolved, and the corneal surface re-epithelialized after flap excision. In 2 other patients, wedge-shaped tissue excision (1.0 x 1.5 mm) from the superior portion of the corneal flap was necessary to allow better flap realignment. In 1 of these patients, the corneal flap was eventually converted to a free cap to correct residual wrinkling. At a mean follow-up of 15 months, the postoperative uncorrected visual acuity ranged from 20/20 to 20/60, and the best spectacle-corrected visual acuity (BSCVA) was 20/30 or better in all patients. In 1 patient, BSCVA decreased by 1 line.

CONCLUSIONS

Flap dislodgment and wrinkling are serious postoperative complications of LASIK. Early recognition of these complications and prompt surgical management are crucial to achieve a successful surgical and visual outcome.

CT of adrenal myelolipoma: report of 7 cases

Seven cases of adrenal myelolipoma are reported. The series consisted of 1 male and 6 females, ranging in age from 30 to 76 years. In 5 cases the tumor originated from the right adrenal, in 1 case from the left adrenal and the remaining patients had bilateral tumors. Symptoms related to the mass were present in 4 cases but in contrast to other reports no hematuria was found in this series. All the tumors laid behind the angles formed by the lateral and medial limbs of adrenals. Fat density dominated in 6 tumors and soft tissue density dominated in 2. Calcification spots were revealed in 3 tumors. In two predominantly soft tissue density tumors the complete peripheral rims were revealed, while in the remaining 6 tumors the peripheral rims were considered incomplete based on the CT images. In 3 cases large amounts of fat were found surrounding the normal contralateral adrenal. The cause is still open to further investigation. Spiral CT with thin collimation provided detailed morphological information for adrenal myelolipoma.

Short-chain fatty acids and thyroid hormone interact in regulating enterocyte gene transcription

BACKGROUND

Enterocyte differentiation is known to be regulated by a variety of extracellular compounds, among which are triiodothyronine (T3) and the short-chain fatty acids (SCFAs). Because several SCFAs are known to induce histone hyperacetylation, and T3 action has been recently linked to chromatin structure, we sought to investigate the interplay between SCFAs and T3 in regard to the enterocyte differentiation marker, intestinal alkaline phosphatase (IAP).

METHODS

Caco-2 cells were transiently transfected with a reporter construct containing 2.4 kb of the human IAP gene 5' flanking region (IAP2.4CAT). Cotransfections were carried out with and without thyroid hormone receptor-1 (TR beta-1) or histone deacetylase-1 (HDAC-1) expression plasmids. Cells were treated with 5 mmol/L SCFAs (propionic, butyric, valeric, or caproic acids as propionate, butyrate, valerate, or caproate, respectively), with and without 10 nmol/L T3. Reporter gene activity was measured and the level of histone acetylation assessed by means of acid-urea-triton (AUT) gel assays.

RESULTS

TR beta-1 cotransfection caused a marked decrease in IAP reporter gene activity, which is consistent with the well-known phenomenon of ligand independent repression (LIR), whereas T3 treatment reversed the LIR and caused further reporter gene activation. Treatment with SCFAs similarly resulted in a complete blockage of LIR, and, in fact, turned the TR beta-1 into a transcriptional activator, even in the absence of T3. Concomitant treatment with T3 and butyric acid produced an additive effect on IAP transactivation. In contrast, cotransfection with HDAC-1 attenuated the effects of SCFAs on IAP gene activation. AUT gel studies demonstrated histone hyperacetylation in response to SCFA treatment.

CONCLUSION

One or more DNA cis-elements in the human IAP gene mediate ligand independent repression by the TR beta-1, an effect that can be entirely reversed by those SCFAs that induce histone hyperacetylation. In addition T3 and SCFAs can act in concert to induce IAP gene transcription, demonstrating an important link between triiodothyronine and histone hyperacetylation in regard to enterocyte-specific gene expression.

Culture-negative ulcerative keratitis after laser in situ keratomileusis

A 40-year old man, highly myopic in both eyes, had laser in situ keratomileusis (LASIK) in the left eye in November 1996. Corneal melting and ulceration and fine striae-like interface infiltrates were noticed 1 day postoperatively. There was no response to intensive topical antibiotics in the form of hourly ofloxacin 3% (Tarivid), and satellite lesions developed on day 4. Corneal scrapings for gram stain and culture were done twice. No bacterial or fungal organisms were identified. Intensive topical fortified vancomycin (50 mg/mL) was added, and the lesions resolved gradually over the ensuing 2 weeks. Eighteen months after LASIK, refraction was -1.50 - 0.75 x 105 in the left eye, and uncorrected visual acuity was 20/70, correctable to 20/25 with spectacles.

Review of circulating tumor markers: from enzyme, carcinoembryonic protein to oncogene and suppressor gene

The ease and non-invasive nature of the procedure for drawing blood has made it possible to measure circulating tumor markers for cancer screening, diagnosis, follow-up and early detection of recurrence. Even though a tumor-specific marker has not yet been found, the specificity and sensitivity of currently used tumor markers have improved over the last several decades as they have progressed from enzyme, hormone and carcinoembryonic protein to monoclonal antibody-defined epitope and finally, in recent years, to oncogene, suppressor gene and their encoded protein product. Both phenotype and genotype are included in these latest new tumor markers. Unlike earlier tumor markers, they can be identified with specific biological processes regulating cell growth, such as the cell cycle, angiogenesis, apoptosis and cell adhesion. Any elevation of these new tumor markers, therefore, can be used to identify defects in a specific metabolic pathway and facilitate the design of effective drug therapy.

Epicutaneous administration of hapten through patch application augments TH2 responses which can downregulate the elicitation of murine contact hypersensitivity

BACKGROUND AND OBJECTIVE

Allergic contact dermatitis and its animal model, contact hypersensitivity (CHS), have long been documented as type 1 T-cell-predominant immune responses. Although type 1/type 2 T-cell deviation has been repeatedly demonstrated to play an important role in many human diseases and their animal models, the potential of tilting type 1/type 2 T-cell differentiation of CHS by modulating the manner of administration and dosage of hapten remains unexplored. This study examined the effect of these two factors on type 1/type 2 balance of CHS.

METHODS

ELISA methods for detection of isotypes of hapten-specific antibodies and cytokine profiles of in vitro reactivation culture as well as ear-swelling assay were used to indicate type 1 or type 2 T-cell immune responses.

RESULTS

In this paper, it was demonstrated that dosage of hapten has no effect on the type 1/ type 2 T-cell balance of CHS, whereas epicutaneous administration of hapten through patch application could tilt the type 1/type 2 balance to decrease type 1 and to augment type 2 T-cell responses. Patch application-induced modulation is still effective in ever-sensitized mice and the augmented type 2 T-cell responses are persistent and increase progressively in strength after repeated immunizations. Moreover, it was demonstrated that the augmented type 2 T-cell response can downregulate the elicitation of CHS. The major mediating cells of the enhanced type 2 T-cell responses were determined to be CD4+ T cells (TH2 cells).

CONCLUSIONS

These data show that epicutaneous administration of hapten through patch application augments TH2 response which can downregulate the elicitation of murine CHS. This exploration may contribute to the understanding of regulatory mechanisms involved in contact allergy.

Impact of assay parameters on the accuracy of free PSA test: source and stability of calibrator, calibration curve fitting, and level of total PSA in the serum

The measurement of PSA is recommended for men over 50 years of age for screening of prostate cancer. However, proper differentiation of prostate cancer from benign prostate hyperplasia (BPH) relies on an accurate measurement of free PSA (fPSA) and a correct calculation of percent fPSA. Because of the extremely low concentration of fPSA in the serum, any slight deviation from its true value may produce large errors in percent fPSA calculated. Therefore, we undertook a study examining carefully those parameters of the fPSA assay which might affect the fPSA determination. We found that the integrity of the calibrator, the computer curve-fitting program selected, the source of the calibrator, and the total PSA or fPSA + PSA complexes (tPSA) concentration of the specimen all had an impact on the accuracy of the fPSA value assayed. We found that an examination of the slope of the calibration curve was important to reveal whether the calibrator had or had not been denatured during storage. We also found that the 4-parameter cure fitting program was best suited for plotting the fPSA calibration curve. The calibrator we isolated from LNCaP cells was acceptable for our assay because it had an affinity for the assay antibody very similar to that of serum fPSA. We also determined the effect of tPSA concentration on the fPSA determinations and found that within the concentration range of 4-10 ng/mL the impact on the percent fPSA calculated was not significant. We believe that our assay produces accurate fPSA values when all these assay parameters are well controlled.

Development of an immunoassay specific for the PSA-ACT complex without the problem of high background

We have developed an assay specific for the PSA-ACT (PSA-alpha 1-antichymotrypsin) complex that effectively diminishes the problem of high assay background commonly reported by other investigators. The assay follows a two-site ELISA format. Polyclonal anti-PSA antibodies were coated on the microplate to capture the PSA complex from the serum, whereas the biotinylated anti-ACT polyclonal antibodies and HRP-conjugated streptavidin were used for detection. The high background ordinarily associated with this assay was greatly reduced when milk casein was added in addition to albumin for blocking and when the Super Block was also included in the diluents for sample dilution and dilution of enzyme conjugated detecting antibodies. The assay has a sensitivity of 0.05 ng/mL. The within-run precision ranges from 4.2-7.2% and the between-run precision falls between 5.8-8.5%. Cross reactions with ACT and free PSA (fPSA) are 0.0001% and 0.02%, respectively. The highest concentration of PSA-ACT complex in the maternal sera was < 0.4 ng/mL by this assay, much less than reported in the literature. Using this improved assay, the sum of fPSA and PSA-ACT concentrations were less than that of their corresponding total PSA (tPSA) most of the time. We believe that this improved assay should be used to replace the current tPSA assay for screening, monitoring, and managing patients with prostate cancer.

Isolation of the intact molecule and ectodomain of C-erbB-2 oncoprotein from SK-BR-3 cells and development of immunoassays on microplate

We isolated both the intact molecule (p185) and the ectodomain (p120) of c-erbB-2 oncoprotein from SK-BR-3 breast tumor cells. The p120 was extracted from the cells by 0.05 M phosphate buffer, pH 7.2, whereas the extraction of the p185 required the presence of a detergent, such as 1% Triton X-100 in 0.05 M Tris buffer. Protease inhibitors were also included in the extraction buffer during the isolation of p185 in order to prevent cleavage of p185 to p120 by an unknown protease apparently also present in the extract. In case there was any p120 in the p185 preparation, the p120 could be separated from p185 by chromatography on a Superose 12 column. Using the p120 and p185 as calibrators, we have established two microplate sandwich immunoassays: one measures both p185 and p120 (total assay) and the other is specific for the p185. Since capturing and detecting antibodies used in the total assay react against the extracellular domain of the c-erbB-2 oncoprotein, they can therefore be used to measure the p120 in serum and p185 in breast tumor tissue cytosol. On the other hand, the p185 specific assay uses the capturing antibody against the cytosolic domain of the oncoprotein and consequently can only measure p185 in breast tumor tissue cytosol.

Development of an assay for modulating anti-acetylcholine receptor autoantibodies using human rhabdomyosarcoma cell line

Three types of autoantibodies against the acetylcholine receptors (AChR) of skeletal muscle are detectable in patients with myasthenia gravis including binding, blocking, and modulating anti-AChR antibodies. Modulating autoantibodies correlate best with the severity of the disease, but are also technically most difficult to measure because the assay generally requires fresh human muscle cells. We have developed an assay for the modulation of anti-AChR antibodies using a rhabdomyosarcoma (RD) cell line expressing AChR on the cell surface. By decreasing the FetalClone III serum from 10% to 0.5% in Eagles Minimal Essential Medium (EMEM) we were able to increase the number of AChR on RD cells to meet the need of sensitivity of the assay. The extent of modulation was determined as the percent of AChR internalized in the presence or absence of modulating autoantibodies. Less than 6% modulation was found with the normal serum (n = 42). The CVs of both the intra- and day-to-day precision were less than 20%. When clinical samples (n = 105) were assayed in our laboratory and also at Nichols Institute, a correlation coefficient of 0.816 was obtained. The selection of RD cell line, the success of increasing the expression of the AChR on RD cells and the use of 125I alpha-bungarotoxin of high specific activity allowed the establishment of an assay which can be used in routine clinical laboratory for the measurement of modulating anti-AChR autoantibodies for the management of patients with myasthenia gravis.

Serum chromogranin A: early detection of hormonal resistance in prostate cancer patients

We monitored both chromogranin A (CgA) and neuron specific enolase (NSE) in serial serum specimens from 14 patients with prostate cancer (CAP patients) showing resistance to hormonal treatment. Elevated serum CgA was detected in 10 out of these 14 patients (71%) during treatment, and an early appearance of elevated serum CgA was found in 6 of 14 (43%) of these patients when serum tPSA levels were still in the normal range. If patients with radical prostatectomy were not included, the percentage of patients showing an early appearance of elevated serum CgA would have been much higher. Elevated serum CgA levels also were found in patients not subject to hormonal therapy. Serial specimens from two out of three prostate cancer patients, randomly selected, contained elevated serum CgA. Serum NSE was not detectable in any of the serial specimens we studied, suggesting that CgA, not NSE, should be used as a marker for neuroendocrine differentiation. We also compared the serum CgA in random serum specimens between patients with BPH (benign prostate hyperplasia) and with prostate cancer in the concentration range of serum tPSA between 3-15 ng/mL. Although serum CgA concentrations in BPH patients overlapped considerably with those levels in patients with prostate cancer, levels > 100 ng/mL should suggest prostate cancer. The early appearance of elevated serum CgA allows an early change of therapy to be made and can lead to the effective prevention of any further development of metastases.

Monitoring percent free PSA in serial specimens: improvement of test specificity, early detection, and identification of occult tumors

We have measured the serum concentration of prostate specific antigen (tPSA) and determined the percent free PSA (% fPSA) in serial specimens from 64 patients with prostate cancer, 35 patients with benign prostate hyperplasia (BPH), and 3 patients with prostitis. We found that the % fPSAs were not a constant for individual patients during the course of the disease. When we compared only the % fPSA of the first specimen of serial specimens from individual patients, who were largely untreated, 37% of BPH specimens were above 22%, whereas only 1.6% cancer samples were above that value. We also found that 67% of cancer specimens and 14% of BPH samples were below 8%, respectively. Although % fPSA distribution pattern remained similar between two types of specimens, less differentiation was found between BPH and prostate cancer in random specimens compared to the study using first specimens of an individual patient's serial samples. Percent fPSA apparently are affected by treatment. However, the most important benefit for the determination of % fPSA appears to be the sensitivity of % fPSA to identify occult tumors when the tPSAs were in the normal concentration range. Determination of % fPSA also seems to improve the specificity of tPSA, not only during screening for the differentiation between BPH and prostate cancer, but also during monitoring of treatment and recurrence.

Advantages of replacing the total PSA assay with the assay for PSA-alpha 1-antichymotrypsin complex for the screening and management of prostate cancer

Several advantages become immediately apparent when the prostate specific antigen (PSA, or tPSA) assay is replaced by the assay specific for the serum PSA-alpha 1-antichymotrypsin (PSA-ACT) complex. For instance, random contributions to the tPSA value by various serum minor PSA isoforms can be avoided, making possible the determination of a more accurate relation of the PSA-ACT concentration to the tumor activity. Discrepancies in percent free PSA (% fPSA) values from the same specimens due to the use of different commercial kits also can be eliminated, mainly because the PSA-ACT assay does not have the problems in antibody selection and calibrator preparation usually associated with the tPSA assay. We found that at the present time different cutoffs of % fPSA for the differentiation of BPH from prostate cancer must be established for each individual tPSA assay. Cutoffs established using values from one tPSA assay should not be used for making clinical decisions when their tPSA values are determined by a different kit. Moreover, when we monitored the patients during treatment with serum tPSA, specific fPSA, and specific PSA-ACT complex assays simultaneously, it was clear that any interpretation of the patient's clinical status based on tPSA values alone could be misleading. Because there is less PSA-ACT complex in BPH specimens relative to that found in cancer serum samples, expressing fPSA as "fPSA/PSA-ACT x 100" and measuring PSA-ACT complex concentrations instead of tPSA during screening improve the measurable contrast between BPH and prostate cancer. Although individually modest, collectively these advantages can add up to considerable improvements.

Algicidal effect of peridinium bipes on microcystis aeruginosa

Peridinium bipes exerted an inhibitory effect on the growth of Microcystis aeruginosa. The algicidal action of water-soluble extract from P. bipes was studied. After treatment with P. bipes extract, the absorption spectrum of M. aeruginosa culture changed markedly, particularly in the ranges of 500 approximately 650 and 420 approximately 460 nm. An increase in absorption in this wavelength resulted from a leakage of phycobilines, both phycocyanin and allophycocyanin, from the treated cells. However, no leakage of chlorophyll was detected. The leakage of phycobilines was a short-term effect, detectable within 1 h of incubation. Both the plasmalemma and thylakoid membranes in M. aeruginosa cells were damaged and distorted in fine structure after treatment with P. bipes extract. It is assumed that algicide from P. bipes exerts its effect on the cell membranes, giving rise to changes in membrane permeability and a dissociation of phycobiline assemblages, but not of chlorophyll complex, on the thylakoid membranes. As a result, phycobilines were leaked out from the cells.

Induction of tumor-specific T cell response by cognating tumor cells with foreign antigen-primed Th cells

Sufficient CD4+ T cell help is very important in generating specific cytotoxic T cell responses. The inadequate activation of tumor-specific Th cells leads to failure of antitumor immunity. In general, each individual consists of some primed Th cells responding to certain antigens. If these tumor non-specific pre-primed Th cells can provide sufficient help, the generation of tumor-specific T cells may be enhanced. In the present study, we tested this hypothesis by cognating and reactivating pre-primed ovalbumin (OVA)-specific Th cells with OVA-pulsed tumor cells which could simultaneously present both OVA and tumor-associated antigen on the same cell. We clearly demonstrated that immunization of OVA-sensitized mice with OVA-pulsed P388 cells, but not unpulsed P388 cells, led to the induction of P388-specific cytotoxicity and tumor resistance. Both CD4+ and CD8+ tumor-specific cytotoxic T cells were detected in vitro, but only CD8+ T cells played the major effector role in preventing the growth of challenged tumor in vivo. Taken together, our study demonstrated that the immunogenicity of tumor cells can be enhanced effectively by cognating pre-primed foreign antigen-specific Th cells with tumor cells. These findings have potential implications in developing methods to control tumor growth.