Prostate involvement during sexually transmitted infections as measured by prostate-specific antigen concentration.

BACKGROUND: We investigated prostate involvement during sexually transmitted infections by measuring serum prostate-specific antigen (PSA) as a marker of prostate infection, inflammation, and/or cell damage in young, male US military members. METHODS: We measured PSA before and during infection for 299 chlamydia, 112 gonorrhoea, and 59 non-chlamydial, non-gonococcal urethritis (NCNGU) cases, and 256 controls. RESULTS: Chlamydia and gonorrhoea, but not NCNGU, cases were more likely to have a large rise (40%) in PSA than controls (33.6%, 19.1%, and 8.2% vs 8.8%, P<0.0001, 0.021, and 0.92, respectively). CONCLUSION: Chlamydia and gonorrhoea may infect the prostate of some infected men.

Longitudinal assessment of urinary PCA3 for predicting prostate cancer grade reclassification in favorable-risk men during active surveillance.

BACKGROUND: To assess the utility of urinary prostate cancer antigen 3 (PCA3) as both a one-time and longitudinal measure in men on active surveillance (AS). METHODS: The Johns Hopkins AS program monitors men with favorable-risk prostate cancer with serial PSA, digital rectal examination (DRE), prostate magnetic resonance imaging and prostate biopsy. Since 2007, post-DRE urinary specimens have also been routinely obtained. Men with multiple PCA3 measures obtained over ⩾3 years of monitoring were included. Utility of first PCA3 score (fPCA3), subsequent PCA3 (sPCA3) and change in PCA3 were assessed for prediction of Gleason grade reclassification (GR, Gleason score >6) during follow-up. RESULTS: In total, 260 men met study criteria. Median time from enrollment to fPCA3 was 2 years (interquartile range (IQR) 1-3) and from fPCA3 to sPCA3 was 5 years (IQR 4-6). During median follow-up of 6 years (IQR 5-8), 28 men (11%) underwent GR. Men with GR had higher median fPCA3 (48.0 vs 24.5, P=0.007) and sPCA3 (63.5 vs 36.0, P=0.002) than those without GR, while longitudinal change in PCA3 did not differ by GR status (log-normalized rate 0.07 vs 0.06, P=0.53). In a multivariable model including age, risk classification and PSA density, fPCA3 remained significantly associated with GR (log(fPCA3) odds ratio=1.77, P=0.04). CONCLUSIONS: PCA3 scores obtained during AS were higher in men who underwent GR, but the rate of change in PCA3 over time did not differ by GR status. PCA3 was a significant predictor of GR in a multivariable model including conventional risk factors, suggesting that PCA3 provides incremental prognostic information in the AS setting.

Use of the Prostate Health Index for detection of prostate cancer: results from a large academic practice.

BACKGROUND: The Prostate Health Index (phi) outperforms PSA and other PSA derivatives for the diagnosis of prostate cancer (PCa). The impact of phi testing in the real-world clinical setting has not been previously assessed. METHODS: In a single, large, academic center, phi was tested in 345 patients presenting for diagnostic evaluation for PCa. Findings on prostate biopsy (including Grade Group (GG), defined as GG1: Gleason score (GS) 6, GG2: GS 3+4=7, GG3: GS 4+3=7, GG4: GS 8 and GG5: GS 9-10), magnetic resonance imaging (MRI) and radical prostatectomy (RP) were prospectively recorded. Biopsy rates and outcomes were compared with a contemporary cohort that did not undergo phi testing (n=1318). RESULTS: Overall, 39% of men with phi testing underwent prostate biopsy. No men with phi<19.6 were diagnosed with PCa, and only three men with phi<27 had cancer of GG⩾2. Phi was superior to PSA for the prediction of any PCa (area under the receiver operating characteristic curve (AUC) 0.72 vs 0.47) and GG⩾2 PCa (AUC 0.77 vs 0.53) on prostate biopsy. Among men undergoing MRI and phi, no men with phi<27 and PI-RADS⩽3 had GG⩾2 cancer. For those men proceeding to RP, increasing phi was associated with higher pathologic GG (P=0.002) and stage (P=0.001). Compared with patients who did not undergo phi testing, the use of phi was associated with a 9% reduction in the rate of prostate biopsy (39% vs 48%; P<0.001). Importantly, the reduction in biopsy among the phi population was secondary to decreased incidence of negative (8%) and GG1 (1%) biopsies, whereas the proportion of biopsies detecting GG⩾2 cancers remained unchanged. CONCLUSIONS: In this large, real-time clinical experience, phi outperformed PSA alone, was associated with high-grade PCa, and provided complementary information to MRI. Incorporation of phi into clinical practice reduced the rate of unnecessary biopsies without changing the frequency of detection of higher-grade cancers.

Calcium supplementation and plasma ferritin concentrations in premenopausal women.

The effect of calcium supplement use on iron stores was examined in a randomized controlled study in free-living, healthy, premenopausal women. Of 109 women who completed the study, 52 were in the control group and 57 took two tablets containing 250 mg Ca as the carbonate with each of two meals daily for 12 wk. In all subjects at baseline, plasma ferritin concentrations were positively correlated with heme-iron intake (r = 0.21, P = 0.04), serum iron concentration (r = 0.19, P = 0.04), transferrin saturation (r = 0.31, P = 0.001), and hemoglobin concentration (r = 0.22, P = 0.02), and negatively correlated with total iron-binding capacity (TIBC, r = -0.42, P < 0.001). No significant differences in absolute or percent changes in plasma ferritin concentrations, serum iron concentrations, TIBC, transferrin saturation, hemoglobin concentrations, or hematocrit were observed between the treatment and control groups. Thus, over a 12-wk period, use of 1000 mg Ca as the carbonate daily with meals does not appear to be detrimental to iron stores in healthy, free-living, premenopausal women.

Comparison of biochemical indexes for assessing vitamin K nutritional status in a healthy adult population.

Biochemical indexes for assessing vitamin K nutritional status were evaluated in 263 healthy subjects (127 males, 136 females) aged 18-85 y. The influences of aging (stratified by decade), menopause, and sex were examined. Total, carboxylated, and undercarboxylated osteocalcin concentrations were affected by sex and aging with increases in the sixth decade in women attributed to menopause. Aging effects in the women and sex differences were eliminated when undercarboxylated osteocalcin was expressed as a percentage of the total. Plasma phylloquinone and undercarboxylated prothrombin (PIVKA-II) concentrations varied little with aging with the exception of lower concentrations of phylloquinone in women in their third decade compared with other ages and higher concentrations of PIVKA-II in younger males compared with younger females. Urinary gamma-carboxyglutamic acid (Gla)-creatinine excretion ratios increased significantly with age in both males (r = 0.68, P < 0.001) and females (r = 0.63, P < 0.001) with values 20% higher in the females on average over the entire age span. The undercarboxylated osteocalcin concentration, shown previously to be responsive to depletion and repletion of phylloquinone, was compared with the other indexes to determine its reliability as an indicator of vitamin K nutritional status. This measure appears promising because it correlated with plasma PIVKA-II concentrations (r = 0.27, P < 0.001) and with plasma phylloquinone concentrations (r = -0.35, P < 0.001), whereas the agreement between plasma phylloquinone and PIVKA-II concentrations was not as strong (r = -0.15, P < 0.05).

Changes in serum osteocalcin, plasma phylloquinone, and urinary gamma-carboxyglutamic acid in response to altered intakes of dietary phylloquinone in human subjects.

The response of osteocalcin and other biochemical markers of vitamin K status to diets formulated to contain different amounts of phylloquinone was assessed in nine healthy subjects aged 20-33 y. Subjects resided in a metabolic ward for two 15-d cycles with a minimum of 6 wk between cycles. A mixed diet containing 100 micrograms phylloquinone/d was fed throughout both cycles; however, the phylloquinone content of one of the cycles was increased to a total of 420 micrograms/d on days 6 through 10 by fortifying corn oil in the diet with phylloquinone (supplemented diet). Total serum osteocalcin concentrations were not affected by either of the dietary treatments. The percentage of undercarboxylated osteocalcin increased an average of 28% over the 15-d cycle with the mixed diet (P < 0.05) and declined significantly an average of 41% with 5 d of the supplemented diet (day 6: 21.9 +/- 1.3%, day 11: 12.8 +/- 1.1%; P = 0.0001) with a rise after the return to the mixed diet (16.7 +/- 1.3%, P < 0.001). Plasma phylloquinone concentrations increased significantly with supplementation (day 6: 0.95 +/- 0.16 nmol/L, day 11: 1.40 +/- 0.29 nmol/L; P < 0.001) and then rapidly returned to presupplementation concentrations on returning to the mixed diet. Twenty-four-hour ratios of urinary gamma-carboxyglutamic acid to creatinine were unchanged with the supplemented diet; however, excretion declined to 91 +/- 2% of baseline after 10 d on the mixed diet (P = 0.01). These results show that undercarboxylated osteocalcin, plasma phylloquinone, and urinary gamma-carboxyglutamic acid excretion appear to be sensitive measures of vitamin K nutritional status because all of these variables were responsive to changes in dietary intake.

Studies on the application of the relative-dose-response test for assessing vitamin A status in older adults.

We investigated the time course and the reproducibility of the relative-dose-response (RDR) test for assessing vitamin A status in older adults. The maximum plasma retinol response to 480 retinol equivalents (RE) of retinyl palmitate in abnormal responses was at 6 or 7 h after dosing compared with the 5-h sampling interval recommended by others for younger adults and children. With respect to reproducibility, the diagnostic concordance of two RDR tests at 7-d intervals in 14 elders was 71%. In 29% of tests, one test was abnormal and the other normal. Linear regression of the two RDR values in these 14 subjects gave a correlation coefficient of -0.08. We conclude that the procedure for the RDR should be modified when applied to persons greater than 60 y of age, and that multiple repetitions of the test are needed to provide a stable indication of vitamin A stores in an elderly individual.

Identifying markers for pancreatic cancer by gene expression analysis.

To begin to identify new tumor markers, we recently performed a systematic study of gene expression in cancers of the colon and pancreas. Of the 45,000 genes identified, 183 were found to be expressed at significantly elevated levels in pancreatic cancer. One of the genes was tissue inhibitor of metalloproteinase type I (TIMP-1), which encodes a secreted protein. Analysis of TIMP-1 serum levels revealed significant increases in pancreatic cancer patients, but TIMP-1 by itself was inadequate as a serum marker for cancer. However, a combination of individually suboptimal markers (TIMP-1, CA19-9, and carcinoembryonic antigen) detected 60% of 85 patients with pancreatic cancers in a highly specific manner. These results suggest that a systematic analysis of gene expression can reveal novel serum markers and that individually suboptimal markers can be combined to yield higher sensitivity and specificity.

Fatty acid synthase (FAS) expression in human breast cancer cell culture supernatants and in breast cancer patients.

Fatty acid synthase (FAS) is selectively expressed in certain human cancers, including carcinoma of the breast, prostate, colon, ovary, and endometrium, compared to normal human tissues and therefore is a putative tumor marker. In this study, we found FAS concentrations were elevated in cell culture supernatants during cell growth in two human breast cancer cell lines but not other cancer cell lines. A quantitative enzyme-linked immunosorbent assay and Western blot analysis were employed in this study. In addition, serum FAS levels were significantly higher in breast cancer patients with different clinical stages (Stage II: 0.59+/-0.09 units/l, Stage III: 0.79+/-0.13 units/l, and Stage IV: 1.39+/-0.35 units/l) compared with healthy subjects (0.27+/-0.02 units/l, P<0.05). Taken together, our data suggest that FAS expression may be a useful tumor marker for breast cancer and play a role in assessing cancer virulence.

Outpatient minimally invasive parathyroidectomy: a combination of sestamibi-SPECT localization, cervical block anesthesia, and intraoperative parathyroid hormone assay.

BACKGROUND: Despite the high cure rate and low morbidity of bilateral neck exploration for primary hyperparathyroidism, there is a movement toward minimizing the process in terms of incision, cost, extent of exploration, and length of hospital stay, while maintaining excellent outcomes. METHODS: Between March and November 1998, 33 patients with primary hyperparathyroidism underwent minimally invasive parathyroidectomy. All had preoperative sestamibi-SPECT scans suggesting a single adenoma, underwent anterior cervical block anesthesia by the surgeon, and were explored through a 1- to 4-cm incision. Intraoperative parathyroid hormone assays were performed before and 5 to 10 minutes after parathyroid resection. Outcomes were compared with those of 184 consecutive patients who underwent bilateral parathyroid exploration under general anesthesia by the same surgeon between August 1990 and May 1996. RESULTS: The mean age of the patients undergoing minimally invasive parathyroidectomy was 61 +/- 2 years, and 24 of the 33 patients were women. Thirty (91%) had resection of a single adenoma under regional anesthesia; 26 of these were done as outpatient procedures. Three patients underwent conversion to general anesthesia for bilateral exploration and were found to have multigland disease (two double adenomas, one hyperplasia). All 33 patients were normocalcemic postoperatively. There was no morbidity. When the minimally invasive parathyroidectomy and bilateral parathyroid exploration groups were compared, they were found to be similar with respect to age, preoperative calcium and parathyroid hormone levels, cause of primary hyperparathyroidism, weight of resected glands, cure rates, and morbidity. However, the minimally invasive parathyroidectomy group had a significantly shorter length of hospital stay (0.3 +/- 0.2 vs 1.8 +/- 0.1 days, P < .001) and lower costs ($3174 +/- $386 vs $6328 +/- $292, P < .001). CONCLUSIONS: Minimally invasive parathyroidectomy is a safe, cost-effective alternative to bilateral exploration and may be the procedure of choice for select patients with primary hyperparathyroidism.

Probability of prostate cancer detection based on results of a multicenter study using the AxSYM free PSA and total PSA assays.

OBJECTIVES: The determination of the percentage of free prostate-specific antigen (%fPSA) enhances the specificity of prostate cancer (CaP) detection. This study was undertaken to assess the performance of %fPSA in differentiating benign prostate disease from CaP and to determine the CaP probability estimates using the AxSYM Free PSA and AxSYM Total PSA assays. METHODS: In this prospective study, 297 men, 50 years old or older, with a total PSA level between 4 and 10 ng/mL and a nonsuspicious digital rectal examination were enrolled at 10 clinical sites. All subjects underwent at least sextant prostate biopsies to establish the diagnosis. fPSA and total PSA (tPSA) levels were determined using the AxSYM Free PSA and AxSYM Total PSA assays. Percent fPSA values were compared with tPSA values to determine the appropriate cutoffs for prostate biopsy and to calculate the CaP probability estimates. RESULTS: The strongest predictor of CaP in a logistic regression model was %fPSA (odds ratio 2.29), which contributed significantly more than age or tPSA to the predictive model. In this study population, a %fPSA cutoff of 26.4% would have detected 96% of subjects with CaP (sensitivity) and would have eliminated 27.4% of unnecessary biopsies (specificity). CaP probability estimates ranged from 9% to 69% and increased as the %fPSA value decreased. Men with a %fPSA level of 10% or lower had a 69% probability of CaP, and men with a %fPSA level of greater than 26% had a 9% probability of CaP. CONCLUSIONS: Percent fPSA values can help differentiate CaP from benign prostate disease and reduce unnecessary biopsies in 27% of men 50 years old or older whose digital rectal examination was normal and whose tPSA level was between 4 and 10 ng/mL. A %fPSA result can assist the physician and patient in determining the probability of CaP and assessing the need for prostate biopsy.

Bone to total alkaline phosphatase ratios improve sensitivity and specificity of bone alkaline phosphatase immunoassays.

OBJECTIVES: Evaluate the ability of two bone alkaline phosphatase (ALPB) immunoassays (Ostase, Hybritech Inc and Alkphase-B, Metra Biosystems) to clinically differentiate between osseous and non-osseous ALP sources. DESIGN AND METHODS: Specimens from patients with either liver or bone disease (Paget's disease or metastatic cancer) were analyzed by both methods. RESULTS: There was a good correlation between these two assays. Values for ALPB, whether determined as a concentration by the Ostase assay or as an activity by the Alkphase-B assay, were similar for subjects with liver disease or bone disease. However, total ALP (ALPT) activity was higher in liver disease compared to bone. When ALPB was expressed in relation to ALPT, ratios were significantly greater in subjects with bone disease than in those with liver disease. ALPB/ALPT ratios improved the specificity of the Ostase assay from 52% to 86% and the Alkphase-B assay from 58% to 74%. CONCLUSIONS: These two ALPB assays have good analytical performance and their clinical utility can be enhanced by expressing ALPB values in relation to ALPT activity.

Prostate-specific antigen. Its discovery and biochemical characteristics.

The search for a more sensitive and specific marker for prostate cancer as well as for use in forensic investigations led to the discovery of PSA. Utilization of the purified protein resulted in the development of many immunoassays that are now in widespread use and have been applied successfully to the detection and monitoring of prostate cancer. Subsequent investigation into the biochemical characteristics of PSA revealed free and complexed forms of PSA in serum whose measurement now may provide additional clinical benefit. Further research into the molecular and biochemical properties of PSA as well as improvements in measurement techniques no doubt will lead to new applications and enhanced clinical use for this important tumor marker.

Two-site ELISA for the quantitative determination of fatty acid synthase.

Fatty acid synthase (FAS) is an enzyme which plays a central role in the de novo biosynthesis of fatty acids. FAS is selectively expressed in certain human cancers and therefore is a putative tumor marker. We developed an enzyme-linked immunosorbent assay (ELISA) for measuring FAS, and investigated its expression and clinical features. In this two-site sandwich ELISA, a polyclonal antibody was used as a capture on Nunc MaxiSorp ELISA/EIA modules and a monoclonal antibody labeled with biotin was used as a signal antibody. The assay was linear with no cross-reactivity with other tumor markers. The within- and between-run CVs were <10%, and the detection limit was 0.15 arbitrary Units/l. Recoveries were 92.4-105.1%. FAS was stable in buffer at 4 degrees C for more than 10 days and stable at 37 degrees C for 2 days. In human serum, FAS levels were significantly higher in patients with breast (1.01+/-0.71 Units/l, mean+/-S.D.), prostate (0.79+/-0.76 Units/l), colon (0.89+/-0.49 Units/l), and ovarian (0.84+/-0.9 Units/l) cancers compared to normal subjects (0.27+/-0.09 Units/l, P<0.01). This assay is sensitive, accurate, and precise and can distinguish between patients with various types of cancer and normal subjects.

Immunosensors--principles and applications to clinical chemistry.

INTRODUCTION: Immunosensors are affinity ligand-based biosensor solid-state devices in which the immunochemical reaction is coupled to a transducer. The fundamental basis of all immunosensors is the specificity of the molecular recognition of antigens by antibodies to form a stable complex. This is similar to the immunoassay methodology. Immunosensors can be categorized based on the detection principle applied. The main developments are electrochemical, optical, and microgravimetric immunosensors. In contrast to immunoassay, modern transducer technology enables the label-free detection and quantification of the immune complex. METHODS: The analysis of trace substances in environmental science, pharmaceutical and food industries is a challenge since many of these applications demand a continuous monitoring mode. The use of immunosensors in these applications is most appropriate. Similarly, a series of clinical problems may be solved by continuous monitoring of certain analytes. CONCLUSIONS: Clinical chemists should take advantage of immunosensors in clinical diagnostics. There are many recent developments in the immunosensor field which have potential impacts. The future role of this technique in intralaboratory, as well as bedside testing, will become even more important as the clinical laboratory is faced with increasing pressure to contain costs.

Rapid parathyroid hormone measurement during venous localization.

The development of a rapid format for intact parathyroid hormone (PTH) immunometric assays has facilitated the use of these assays intraoperatively as a guide to parathyroid surgery. The near real-time characteristics of this rapid PTH assay led us to evaluate its utility in the angiography suite in a patient who underwent venous localization for persistent primary hyperparathyroidism. The assay provided the angiographers with almost immediate feedback and thereby facilitated accurate parathyroid adenoma localization. We conclude that the performance characteristics of the rapid PTH assay extend its diagnostic utility to near real-time analysis of plasma PTH levels in patients undergoing venous catheterization for parathyroid localization.

Assessment of dietary phylloquinone intake and vitamin K status in postmenopausal women.

OBJECTIVE: To examine the relationship between dietary phylloquinone intake and vitamin K status of postmenopausal Caucasian women. DESIGN: Cross-sectional study, in which dietary intake was estimated using weighed record techniques and vitamin K status was measured by a single plasma phylloquinone concentration and 24-h urinary gamma-carboxyglutamic acid (Gla) excretion. SETTING: The metabolic research unit at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA. SUBJECTS: 402 healthy postmenopausal Caucasian women who were participating in a randomized trial to determine the effect of calcium supplementation on bone loss. Of the original group, 362 had complete weighed diet records, 358 had corresponding plasma phylloquinone concentrations, and 346 had corresponding urinary Gla measurements. RESULTS: There was a significant correlation (r = 0.13, P = 0.01) between total dietary intake of phylloquinone (geometric mean = 89 micrograms/day) and plasma phylloquinone levels (mean = 1.12 nmol/l). Dietary intake was neither correlated with urinary Gla excretion (mean = 4.0 mumol/mmol creatinine) nor did it vary by season. The ratio of intra- to interindividual variance in phylloquinone intake was 2.6, from which it was estimated that 5 days of independent recording is necessary to estimate true usual dietary intake, assuming a correlation of 0.8. CONCLUSIONS: A weighed record has the potential to be a reliable method for estimating dietary intakes of vitamin K which relate to plasma phylloquinone levels used as an indicator of vitamin K status in postmenopausal Caucasian women.

Redesigned proficiency testing materials improve survey outcomes for prostate-specific antigen. A College of American Pathologists Ligand Assay Survey tool.

CONTEXT: Large disparities in prostate-specific antigen (PSA) results from different assays have been observed in the College of American Pathologists (CAP) Ligand Assay Survey, with interassay results varying severalfold. Survey specimens are predominately composed of free PSA and do not reflect the composition of typical patient specimens. OBJECTIVES: To characterize a pilot material developed for CAP in which pooled sera samples were spiked with purified PSA and alpha(1)-antichymotrypsin-bound PSA at targeted concentrations and to compare it to CAP survey and reference materials. DESIGN: CAP survey, reference, and pilot materials were analyzed using 10 total PSA and 7 free PSA assays. These assays included Food and Drug Administration-approved assays and assays for research use only. RESULTS: Variability among the 10 total PSA methods was greatest for the 1997 ligand survey material (CV range, 56%-65%) followed by the pilot material (CV range, 10%-29%) and the reference material (CV range, 6%-13%). In contrast, interassay variability for the 7 free PSA methods was similar for the 3 preparations, with the exception of one specimen close to the limit of detection of the assays. As determined with the Hybritech Tandem-R method, the ligand survey specimens were essentially composed of all free PSA, whereas the reference and pilot materials were composed of approximately 10% and 35% free PSA, respectively. CONCLUSIONS: The newly formulated pilot material prepared using a human base that contained defined concentrations of free PSA and alpha(1)-antichymotrypsin-bound PSA more closely resembled patient specimens and minimized differences among methods compared with the semen-supplemented original survey material.

The interaction between vitamin K nutriture and warfarin administration in patients with bacterial overgrowth due to atrophic gastritis.

Atrophic gastritis patients have intestinal bacterial overgrowth which could produce menaquinones. The aim of this study was to evaluate the interaction between a diet low in phylloquinone and minidoses of warfarin in subjects with and without bacterial overgrowth. Subjects with atrophic gastritis (indicated by serum pepsinogen ratio) and healthy volunteers were studied while fed a restrictive phylloquinone diet and while receiving a minidose of warfarin. Coagulation times, serum osteocalcin, serum undercarboxylated osteocalcin, plasma phylloquinone, plasma K-epoxide, plasma undercarboxylated prothrombin (PIVKA)-II and urinary gamma-carboxyglutamic acid (Gla) were measured. At baseline, there were no differences between groups for any variable measured. Comparisons between baseline and post intervention in both groups, showed significant increases in circulating levels of K-epoxide, PIVKA II and undercarboxylated osteocalcin. However, no differences were observed when comparisons were made between groups. Our data do not support the hypothesis that bacterial synthesis of menaquinones in patients with bacterial overgrowth due to atrophic gastritis confers considerable resistance to the effect of warfarin.