Stability of first trimester placental growth factor in serum and whole blood

BACKGROUND

Placental growth factor (PlGF) is a proposed first-trimester screening marker for pre-eclampsia. This study investigates the stability of PlGF in serum and whole blood at typical routine storage temperatures.

METHODS

Serum pools were stored at refrigerator temperature, room temperature or 30 °C for up to 30 days, or exposed to up to six freeze-thaw cycles. Whole blood was stored at room temperature or 30 °C for up to 6 days. PlGF was quantified using a DELFIA Xpress analyser.

RESULTS

Placental growth factor levels increased over time, seemingly because of the dissociation of PlGF bound to a soluble binding protein, sFlt-1. Increase was slow in serum at refrigerator temperature, remaining stable (less than 10% change from start point) for at least 30 days. At room temperature PlGF was stable for 3.3 days and at 30 °C for 1 day. Serum PlGF remained stable for at least six freeze-thaw cycles. In whole blood, instability was worse, being stable for only 19.4 h at room temperature and just 3.3 h at 30 °C.

CONCLUSION

Routine screening of sample handling requires careful monitoring. However, no extra precautions need to be taken when PlGF is used for pre-eclampsia screening run alongside existing first trimester aneuploidy screening programs that include hCGβ.

Human papillomavirus infection and primary fallopian tube carcinoma: a seroepidemiological study

OBJECTIVE

To evaluate the role of human papillomavirus (HPV) types 6, 11, 16, 18, 31 or 33 infection in primary fallopian tube carcinoma (PFTC).

DESIGN

A retrospective case-control study.

SETTING

Department of Obstetrics and Gynaecology, Helsinki University Hospital, Finland.

POPULATION

Seventy-eight consecutive women with PFTC diagnosed between 1985 and 2000 were studied. For each case, two healthy controls were selected.

METHODS

Serum immunoglobulin G antibodies to HPV types 6, 11, 16, 18, 31 and 33 were measured from women with PFTC and their healthy controls.

MAIN OUTCOME MEASURES

Analysis of HPV 6, 11, 18, 31 and 33 seropositivity among women with PFTC and controls.

RESULTS

Seropositivity rates of non-oncogenic or oncogenic HPV types did not differ between cases and controls, odds ratios being 1.04-1.30 for oncogenic HPVs and 1.08-1.19 for non-oncogenic HPVs, similarly. We did not find any multiplicative joint effect in PFTC by antibodies to more than one oncogenic HPV type; neither did we find any antagonistic effect among women with antibodies to non-oncogenic and oncogenic HPV types.

CONCLUSIONS

Our results do not suggest any link between PFTC and serological evidence for HPV infection.

Past chlamydial infection is not associated with primary fallopian tube carcinoma

We conducted a retrospective seroepidemiological study to evaluate the relationship between past chlamydial infection and primary fallopian tube carcinoma (PFTC). Postoperative serum samples were drawn from 79 consecutive patients treated for PFTC in 1985-2000. For each case two controls were selected. Serum samples were analysed for IgG antibodies to different C. trachomatis serotype pools and to C. pneumoniae. Seropositivity in general or serum antibody levels to different C. trachomatis serovars or C. pneumoniae did not differ between PFTC patients and controls. The lack of association between anti-chlamydial antibodies and PFTC suggests that past chlamydial infection does not play a role in the etiopathogenesis of PFTC. However, because chlamydial infection is common at young age and PFTC develops decades later, we cannot definitively exclude the possibility that C.trachomatis contributes to the development of PFTC.

Preoperative Serum hCGβ as a Prognostic Marker in Primary Fallopian Tube Carcinoma

OBJECTIVES

It was the aim of this study to evaluate the prognostic value of the pretreatment serum concentrations of the beta-subunit of human chorionic gonadotropin (hCGbeta), CA 125 and tumour-associated trypsin inhibitor (TATI) in primary fallopian tube carcinoma (PFTC).

METHODS

The pretreatment serum concentrations of hCGbeta, CA 125 and TATI were analyzed in serum samples from 60 women with a mean age of 61 years, treated for PFTC between 1985 and 2000. Of the 91 patients treated during this period, 31 were excluded because no serum sample was available. The patients were followed-up for recurrence and survival until February 14, 2003. The prognostic value of the serum markers were compared with those of stage, grade and histological type.

RESULTS

The median survival time was 27 months and the overall 5-year survival rate 33%. Stage and size of the residual tumour (<1 vs. > or =1 cm) predicted both overall and disease-free survival (p < 0.050). Histology (serous vs. others) (p = 0.023) also influenced overall survival. Overall 5-year survival was 38% when serum hCGbeta was below 3.5 pmol/l, while it was 18% when the level was higher (p = 0.052). The corresponding disease-free 5-year survival was 38 and 20%, respectively (p = 0.014). Patients with CA 125 values above 1,017 kU/l had an overall 5-year survival of 39% as compared with 14% for those with lower values (p = 0.009), while the disease-free survival was 37 and 23%, respectively (p = 0.096). Serum TATI was not a prognostic marker. Serum concentrations of hCGbeta and CA 125 correlated significantly with stage (p = 0.049 and p = 0.050, respectively). In multivariate Cox proportional hazards regression analysis, only hCGbeta, stage and histology emerged as independent prognostic factors.

CONCLUSIONS

Clearly elevated serum concentrations of hCGbeta and CA 125 predict survival in fallopian tube carcinoma, but in multivariate analyses, only hCGbeta is a prognostic factor independent of stage and histology.

Noninvasive dual modality in vivo monitoring of the persistence and potency of a tumor targeted conditionally replicating adenovirus

In clinical trials with cancer patients, the safety of conditionally replicating adenoviruses (CRAds) has been good. However, marginal data are available on the persistence or antitumor efficacy of these agents. The oncolytic potency of CRAds is determined by their capacity for entering target cells. Consequently, we constructed a retargeted CRAd featuring a secreted marker protein, soluble human carcinoembryogenic antigen (hCEA), which can be measured in growth medium or plasma. We found that virus replication closely correlated with hCEA secretion both in vitro and in vivo. Further, antitumor efficacy and the persistence of the virus could be deduced from plasma hCEA levels. Finally, using in vivo bioluminescence imaging, we were able to detect effective tumor cell killing by the virus, which led to enhanced therapeutic efficacy.

Midnight serum cortisol: comparison of healthy volunteers and hospitalized patients with Cushing's syndrome

Diurnal variation in serum cortisol is nearly always absent in patients with Cushing's syndrome (CS), as shown by elevated levels of midnight serum cortisol (MSC). The sensitivity of MSC in the diagnosis of CS has been shown to be 96-100% measured on an inpatient basis. The purpose of this study was to state reference values for MSC measured on an outpatient basis in healthy non-sleeping controls, and to calculate the sensitivity and specificity of the test in patients with verified CS based on these data. Thirty-six healthy volunteers (11 males, 25 females) with a median age of 40.5 (range 22-60) years and a mean body mass index (BMI) of 27.0+/-5.9kg/m2 were included in the study. Serum cortisol was measured at 24.00h. In 35 CS patients (5 males, 30 females) with a median age of 44.5 (range 23-79) years and mean BMI of 28.5+/-6.9 kg/m2, MSC was measured on the first night after admission to hospital, in a non-sleeping state. All controls, with the exception of one, had MSC values below 200nmol/L. One CS patient showed an MSC level below 200nmol/L. Based on these observations, the sensitivity and specificity of the test were 97.1% and 97.2%, respectively, when 200nmol/L was used as the cut-off limit. Non-sleeping state does not seem to compromise the sensitivity or the specificity of the test.

CEA, CA 19-9 and CA 72-4 improve the diagnostic accuracy in gastrointestinal cancers

BACKGROUND

CEA, CA 19-9, CA 242 and CA 72-4 are commonly used tumour markers for gastrointestinal malignancies. The advantage of the concomitant use of these markers is under debate.

MATERIALS AND METHODS

Serum concentrations of the markers were measured at the time of diagnosis in 161 patients with benign and 125 with malignant gastrointestinal diseases. Concomitant use of the markers was evaluated in a logistic regression model.

RESULTS

CA 19-9, CA 242 or CA 72-4 showed similar sensitivity of 44% for gastric cancer, whereas CEA was elevated in 25% of the cases. In patients with colorectal cancer, CEA was most frequently elevated (54%), followed by CA 242 (46%), CA 19-9 (36%) and CA 72-4 (25%). High CA 19-9 and CA 242 serum levels were frequent in patients with cholangiocarcinoma (86% and 68%, respectively) and pancreatic cancer (80% and 63%, respectively). In the benign disease group, serum CA 19-9 was most frequently elevated, i.e. in 24%, 25% and 38% of patients with pancreatic, biliary and liver disorders, respectively. The overall accuracy of CEA, CA 19-9, CA 242 and CA 72-4 was 66%, 71%, 71% and 66%, respectively (p > 0.18). When combined in a logistic regression model, CA 72-4, CA 19-9 and CEA provided independent diagnostic information, whereas CA 242 contributed with independent diagnostic information only on excluding CA 19-9. The probability of cancer for each patient, calculated with the model, was applied as a diagnostic test and was compared with the single markers by ROC-curve analysis. The AUC value of the probability index was significantly higher than the values of the different tumour markers.

CONCLUSION

An algorithm based on the combination of CEA, CA 19-9 and CA 72-4 improved the diagnostic accuracy in gastrointestinal tract malignancies compared with these markers alone.

Serum tumour markers CA 15-3, TPA, TPS, hCGbeta and TATI in the monitoring of chemotherapy response in metastatic breast cancer

The clinical utility of CA 15-3, polypeptide specific antigen (TPS), tissue polypeptide antigen (TPA), human chorionic gonadotropin (hCGbeta) and tumour-associated trypsin inhibitor (TATI) as indicators of chemotherapy response was assessed in advanced breast cancer. Serum was prospectively collected in one center before treatment (after the first course of chemotherapy) and at response evaluation from 57 patients taking part in a multicentre randomized trial comparing docetaxel with sequential methotrexate and 5-fluorouracil in the treatment of advanced breast cancer. The pretreatment levels of the serum markers were not predictors of the later response to treatment. Changes in the TPS level showed the strongest association with clinical response after the first course of chemotherapy and CA 15-3 at the best response evaluation. However, distinct mismatches occurred with every marker. The most problematic error was an increase in marker levels in patients with clinical responses, which might have caused interruption of therapy. This occurred in 8% and 17% of patients after the first course of chemotherapy and in 4% and 17% of patients at the best response evaluation with CA 15-3 and TPS, respectively. Moreover, after the first course of chemotherapy only 39% and 33% of the patients with progressive disease could be identified on the basis of increasing levels of CA 15-3 and TPS. respectively. Later, at clinical disease progression, TPA and TPS were found to be better indicators of disease progression than CA 15-3. In conclusion, changes in CA 15-3 or TPS levels usually correlate with clinical response, but owing to distinct discordances, they should not be used as sole indicators of response to chemotherapy in advanced breast cancer.

The free beta-subunit of human chorionic gonadotropin as a prognostic factor in renal cell carcinoma

The free beta-subunit of human chorionic gonadotropin beta is expressed in several nontrophoblastic tumours and this is usually associated with aggressive disease. Little is known about human chorionic gonadotropin beta expression in renal cancer. We determined the pretreatment levels of human chorionic gonadotropin beta in serum of patients with renal cell carcinoma, and studied whether elevated levels predicted the clinical outcome. Serum samples were collected before surgery from 177 patients with renal cell carcinoma and from 84 apparently healthy controls. Human chorionic gonadotropin beta in serum was measured by a highly sensitive time-resolved immunofluorometric assay. The prognostic value of human chorionic gonadotropin beta, and of usual clinical and pathological variables was analyzed by the Kaplan-Meier method, the log rank test and Cox multiple hazard regression. The serum concentrations of human chorionic gonadotropin beta were increased in 23% of the renal cell carcinoma patients and they were significantly higher in patients with renal cell carcinoma than in controls (P<0.0001). The concentrations did not correlate with clinical stage and histopathological grade, but patients with increased human chorionic gonadotropin beta levels had significantly shorter survival time than those with levels below the median (cut-off 1.2 pmol l(-1), P=0.0029). In multivariate analysis human chorionic gonadotropin beta, tumour stage and grade were independent prognostic variables. The serum concentration of human chorionic gonadotropin beta is an independent prognostic variable in renal cell carcinoma. The preoperative value of human chorionic gonadotropin beta in serum may be used to identify patents with increased risk of progressive disease.

Comparison of HPLC and small column (CDTect) methods for disialotransferrin

BACKGROUND

Current methods for determination of carbohydrate-deficient transferrin (CDT) are based on separation of the CDT fraction by ion-exchange chromatography on minicolumns and quantification by immunoassay. Alternatively, the transferrin isoforms can be separated by HPLC anion-exchange chromatography and quantified by absorbance. This method has been reported to improve the validity of CDT as a marker of chronic alcohol abuse.

METHODS

HPLC on either MonoQ or ResourceQ anion-exchange columns was used to separate and quantify isoforms of transferrin with detection at 460 nm. The result was expressed as the percentage of the disialo form (pI 5.7) of total transferrin (DST). The commercial CDTect assay was used as a comparison method. Serum samples from nondrinkers (n = 57), moderate drinkers (n = 77), and heavy drinkers (n = 139) were analyzed.

RESULTS

In ROC analysis for differentiation between moderate and heavy drinkers, the area under the curve (AUC) for the HPLC method was 0.87 (95% confidence interval, 0.81-0.93), whereas that for CDTect was 0.72 (95% confidence interval, 0.64-0.80). At 90% specificity, the sensitivity of DST was 63% (95% confidence interval, 53-73%) compared with 33% (22-44%) for CDT. The reference interval of the HPLC method was 0.68-1.7%.

CONCLUSIONS

The HPLC anion-exchange method for quantification of CDT provides substantially better separation between moderate and heavy drinkers than the CDTect method.

Preoperative serum concentration of hCGbeta as a prognostic factor in ovarian cancer

In spite of a gradual improvement, survival in epithelial ovarian cancer is disappointingly low. New therapeutic regimens are emerging, and it would be important to be able to predict the prognosis and to stratify patients for clinical trials before therapy. We have evaluated the prognostic value of the pretreatment serum concentrations of 3 tumor markers. The free beta subunit of human chorionic gonadotropin (hCGbeta), CA125 and tumor-associated trypsin inhibitor (TATI) were measured in pretreatment serum samples from 146 patients treated for ovarian cancer between 1990-1995. The patients were followed up until 1998. Elevated concentrations of hCGbeta, CA125 and TATI were observed in 29%, 79% and 33%, respectively. When tested as single variables in Cox's proportional hazards model, stage, grade, size of residual tumor and hCGbeta (all p < 0.001) and CA125 (p = 0.004) correlated with prognosis. However, when fitted as multiple variables together with stage, grade and age in the same model, hCGbeta (RR = 3.42) stage (RR = 2.77) and grade (RR = 3.80) were the only significant variables. When serum hCGbeta was normal, 5-year survival was 80%, but it was only 22% when hCGbeta was elevated. In patients with stage III or IV and minimal residual disease, 5-year survival was 75% if hCGbeta was normal compared with 0% if hCGbeta was elevated. hCGbeta in serum is a strong independent prognostic factor in epithelial ovarian cancer, and its prognostic value is similar to that of grade and stage. The availability of this marker before surgery could facilitate selection of treatment modalities.

Specific staining of human chorionic gonadotropin beta in benign and malignant gastrointestinal tissues with monoclonal antibodies

AIMS

Human chorionic gonadotropin (hCG) beta in serum is a promising tumour marker for gastrointestinal malignancies. Our aim was to investigate the expression of hCGbeta by immunohistochemistry in various gastrointestinal cancers and benign tissues.

METHODS AND RESULTS

A monoclonal antibody (MAb) specific for free hCGbeta was used to stain 107 tissue samples from various gastrointestinal malignancies and 36 benign or normal tissue samples. The specificity of the staining was verified and the results compared with those obtained with a widely used commercial polyclonal antibody (PAb) which reacts with both free hCGbeta and intact hCG, as well as with luteinizing hormone beta. With the MAb, we observed positive immunohistochemical staining in 24% of the malignant gastrointestinal tumours. Gastric (60%) and pancreatic (56%) carcinomas, as well as extrahepatic cholangiocarcinomas (36%), were positive most frequently. We also discovered immunoreactivity in half of the non-malignant samples from pancreatic and biliary tissues. With the PAb, hCG immunoreactivity was evident more frequently in some cancers, but the staining was diffuse and occasionally polymorphonuclear leucocytes were strongly stained.

CONCLUSIONS

This study shows that our MAbs specific for hCGbeta are well suited for immunohistochemistry. Our results confirm previous findings on gastrointestinal cancers and, furthermore, we demonstrate hCGbeta tissue expression in pancreatic adenocarcinoma. The results support reports on hCGbeta as a serum tumour marker for digestive tract diseases.

Tissue expression of human chorionic gonadotropin beta predicts outcome in colorectal cancer: a comparison with serum expression

Production of the glycoprotein hormone human chorionic gonadotropin beta (hCGbeta) has been associated with more aggressive behavior in non-trophoblastic tumors. In this study, the prognostic value of immunohistochemical hCGbeta expression was evaluated in 239 patients with colorectal cancer. Paraffin-embedded, formalin-fixed specimens were stained with hCGbeta-specific monoclonal antibody, and the results were compared with serum levels determined with an assay based on the same antibody. hCGbeta immunoreactivity was seen in 52 of 239 tumors (22%). The difference in survival time between patients with histologically hCGbeta-negative (median survival 94 months) and -positive (median survival 27 months) tumors was statistically significant (p = 0.014). The risk ratio during follow-up for patients with positive hCGbeta tissue expression was 1.65 (95% CI 1.11-2.46). In a Cox multivariate analysis, Dukes' stage, hCGbeta and age remained independent prognostic factors. There was moderate agreement between immunohistochemical and serum expression levels of hCGbeta (kappa = 0.30). Using a combination of histological and serum levels of hCGbeta, the difference between survival rates was highly significant (p < 0.001). The accuracy when predicting 5-year survival status with the combined results of serum and tissue expression was 1.3% higher compared to hCGbeta tissue expression alone. Our results show that hCGbeta expression in both tumor tissue and serum has prognostic significance independent of other clinicopathological variables. Positive tumor staining does not always occur together with elevated serum levels, and the prognostic accuracy can slightly be increased by combining the results.

Effect of an in vitro fertilization program on serum CA 125, tumor-associated trypsin inhibitor, free beta-subunit of human chorionic gonadotropin, and common alpha-subunit of glycoprotein hormones

OBJECTIVE

To investigate the impact of an IVF program on serum levels of tumor markers CA 125, tumor-associated trypsin inhibitor, free hCG beta-subunit, and free glycoprotein hormone alpha-subunit.

DESIGN

A prospective controlled clinical study.

SETTING

Outpatient university infertility clinic.

PATIENT(S)

Seventy-one infertile patients (with tubal occlusion, pelvic endometriosis, or unexplained infertility) undergoing IVF and nine control women with regular menstrual cycles.

INTERVENTION(S)

Serial blood sampling before, during, and after IVF, or during one ovulatory menstrual cycle in the controls.

MAIN OUTCOME MEASURE(S)

Serum levels of CA 125, tumor-associated trypsin inhibitor, hCG-beta, and glycoprotein hormone-alpha.

RESULT(S)

Before IVF, all tumor markers were within the normal range except for CA 125, which was elevated in patients with endometriosis. IVF led to significant increases in CA 125 and glycoprotein hormone-alpha that differed from the changes seen during normal menstrual cycles. The luteal phase increase in CA 125 correlated with levels of E(2) and P and the number of follicles. Two months after IVF, levels of CA 125 were 12% higher than levels before treatment. Tumor-associated trypsin inhibitor and hCG-beta revealed no cyclicity.

CONCLUSION(S)

An IVF regimen increased the release of CA 125 and glycoprotein hormone-alpha. The CA 125 elevation after IVF implies a persistent effect of ovarian hyperstimulation on CA 125 release.

A comparison of serum and tissue hCG beta as prognostic markers in colorectal cancer

BACKGROUND

Production of the glycoprotein hormone hCG beta has been associated with aggressive behavior in nontrophoblastic tumors. In this study the prognostic value of serum level and tissue expression of hCG beta were compared in 232 patients with colorectal cancer.

MATERIALS AND METHODS

Serum levels were measured with a hCG beta specific immunofluorometric assay. Tissue specimens were stained with the same monoclonal antibody as in the serum assay.

RESULTS

The proportion of patients with a positive immunohistochemical expression of hCG beta was higher (22%) than the proportion with elevated serum levels (17%). The correlation between serum and tissue expression was moderate (kappa 0.298). Both serum and tissue expression of hCG beta were independent prognostic factors. hCG beta serum level was a stronger prognostic factor than tissue expression both in uni- and in multivariate analysis. The accuracy when predicting 5-year survival status of the patients was highest (63%) when using the combined results of serum and tissue expression.

CONCLUSIONS

There is a moderate correlation between hCG beta expression in serum and in tissue. The predictive accuracy of serum hCG beta was higher than the predictive accuracy of tissue expression, and the prognostic accuracy was further slightly increased when using a combination of tissue and serum expression.

No evidence for extraocular light induced phase shifting of human melatonin, cortisol and thyrotropin rhythms

The view that light affects the mammalian circadian clock only through the eyes was recently challenged by a study in which the phases of human circadian rhythms were shifted by extraocular light exposure. This finding has not been confirmed, however. We studied the effects of light exposure (3 h, broad spectrum fluorescent white light, 13000 lux) on abdomen and chest on the circadian rhythms of serum melatonin, cortisol and thyrotropin in six subjects. The protocol consisted of two 3-day sessions in a dimly lit (< 10 lux) experimental unit. In both sessions hourly serum samples were collected for hormone analysis on days 1 and 3. The skin light exposure was delivered on day 2 from 22.00 to 01.00h in one of the two sessions in a randomized order. In both sessions all three rhythms tended to delay, presumably due to the endogenous circadian cycle length being slightly longer than 24 h. However, the phase shifts did not differ significantly between the sessions. Thus, the present study does not support the existence of extraocular photic regulation of the circadian rhythms in humans.

Ovarian hyperstimulation caused by gonadotroph adenoma secreting follicle-stimulating hormone in 28-year-old woman

Ovarian hyperstimulation caused by a gonadotroph adenoma in premenopausal women has been described only twice before this report. A 28-yr-old woman presented with menstrual disturbances and pelvic pains that began after stopping the use of contraceptive pills. Transvaginal ultrasound revealed enlarged ovaries with multiple cysts. The patient had elevated serum estradiol (up to 2900 pmol/L; normal, 80-300 pmol/L in the follicular phase) and inhibin (6.4 kU/L; normal, 0.5-2.5 kU/L) levels. Serum LH was appropriately suppressed (0.6 IU/L), but serum FSH varied from 4.9-8.1 IU/L. Both gonadotropins as well as the free alpha-subunit showed a paradoxical response to the stimulus by TRH. A nuclear magnetic resonance study unraveled a pituitary tumor, 12-14 mm in diameter, extending up to the suprasellar cistern. After pituitary surgery, all hormone values normalized, and the patient resumed regular ovulatory cycles. In immunostaining, 20-30% of the cells of the tumor stained positively for FSHbeta. We conclude that a gonadotropin-producing adenoma must be considered in the differential diagnosis of a patient presenting with large multicystic ovaries and high estradiol levels in the absence of exogenous gonadotropins.

Concentration of free hCGbeta subunit in serum as a prognostic marker for squamous-cell carcinoma of the oral cavity and oropharynx

This study was conducted to evaluate the clinical usefulness of serum hCGbeta in the diagnosis and prognosis of patients (n = 59) with cancers of the oral cavity and oropharynx. As a reference marker we used squamous-cell carcinoma antigen (SCCAg). A blood sample was obtained from all patients before primary surgery. Serum hCGbeta was determined by a time-resolved immunofluorometric assay (IFMA) and SCCAg by a solid phase immunoenzymometric assay. Elevated preoperative hCGbeta levels were observed in 8 (14%) and elevated SCCAg in 12 (20%) out of 59 patients. Patients with preoperatively elevated hCGbeta had a shorter recurrence-free survival when compared with those with normal hCGbeta levels (log-rank Chi-squared = 6.83, p =.009), and the risk-ratio for recurrence during follow-up for those was 3.6 (95% CI = 1.29-9.94). In a Cox multivariate model hCGbeta (p = 0.039) and stage (p = 0.044) were independent prognostic factors. SCCAg showed no correlation with recurrence-free survival. We conclude that determination of hCGbeta in serum is a potential marker in the prognostic evaluation of patients with SCC of the oral cavity and oropharynx.

Skin metastases of gynecologic adenocarcinomas affect serum levels of hCGbeta but not those of SCC antigen

Squamous cell carcinoma antigen (SCC-Ag) has been shown to be elevated in patients with epidermoid carcinoma of the cervix but also in patients with benign tumors of epithelial origin and in benign skin disorders. Elevated serum levels of the free beta subunit of human chorionic gonadotropin (hCGbeta) have been observed in patients with cancer of different types, and cancer aggressiveness is related to hCGbeta expression. Therefore, we expected that extensive metastatic skin dissemination of gynecologic malignancies would cause a rise in the serum levels of SCC-Ag and hCGbeta. The serum levels of SCC-Ag, hCGbeta and CA 125 were monitored in 2 patients with extensive skin dissemination of ovarian and endometrial adenocarcinoma. Skin metastases had no effect on serum levels of SCC-Ag but they caused an increase in serum levels of hCGbeta. SCC-Ag is not a marker for metastatic skin lesions of gynecologic carcinomas of nonepidermoid origin. hCGbeta expression is associated with aggressiveness of cancer and may be a useful marker indicating therapy resistance.

Vascular endothelial growth factor is bound in amniotic fluid and maternal serum

To study vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) concentrations and their possible binders, serum from 22 non-pregnant and 55 pregnant women (15 at weeks 10-13; 40 at term), umbilical vein (n = 24) and artery (n = 13) and amniotic fluid (a pool of 50 at weeks 15-17; 11 at term) were assessed for VEGF and PlGF by an enzyme-linked immunosorbent assay. In amniotic fluid and maternal serum VEGF concentrations were <16 ng/ml and added VEGF was not recovered. VEGF was detected in serum from mothers post-partum (137 +/- 142 ng/l, mean +/- SD), umbilical artery (421 +/- 288 ng/l) and vein (502 +/- 339 ng/l) and non-pregnant controls (182 +/- 147 ng/l), and added VEGF was fully recovered. PlGF was detected in pregnancy serum (52 +/- 23 ng/l early pregnancy; 439 +/- 217 ng/l term pregnancy) and in amniotic fluid (early pregnancy 56 ng/l; term pregnancy 30 +/- 18 ng/l). PlGF was fully recovered in all samples. Gel filtration and isoelectric focusing revealed that in maternal serum and amniotic fluid [125I]VEGF was bound to a protein with an Mr of 400-700 kDa and an isoelectric point of approximately 8. This protein was not identical with alpha-2-macroglobulin (by an immunofluorometric assay), pregnancy zone protein or pregnancy associated plasma protein-A (by immunodiffusion). In conclusion, VEGF-binding activity is present in amniotic fluid and maternal blood. It disappears after delivery and is not detectable in fetal or non-pregnant serum.

Identification of choriocarcinoma by the hCG beta-to-hCG proportion in patients with delayed diagnosis caused by contraceptive use

The use of contraceptives, especially subdermal implants and levonorgestrel-containing intrauterine device (IUD), often cause irregular bleeding. Thus, they may mask unsuspected choriocarcinoma, which also often presents with abnormal bleeding. Choriocarcinoma is mostly curable with combination chemotherapy, but delayed diagnosis can lead to treatment failure. Two cases of choriocarcinoma with considerable delay in diagnosis, due partly to contraceptive use, are reported. The proportion of human chorionic gonadotropin-beta (hCG beta) and total hCG immunoreactivity showed that the proportion of hCG beta was elevated at presentation in both cases.

Disappearance of human chorionic gonadotropin and its alpha- and beta-subunits after term pregnancy

We have used high-specificity and precision immunofluorometric assays to measure the elimination half-times of human chorionic gonadotropin (hCG), hCG alpha, and hCG beta in serum over 21 days after delivery in six women with term pregnancies. Baseline concentrations and half-times were calculated with the use of a curve-fitting algorithm for multiexponential decay. In contrast to the two-component model, a three-component exponential function with baseline provided a fit for which predicted values could not be distinguished from the observed values by analysis of variance. Median half-times were 3.6, 18.0, and 53.0 h for hCG; 1.0, 23.4, and 194 h for hCG beta; and 0.6, 6.2, and 21.9 h for hCG alpha. The mean ratio of hCG alpha to hCG decreased rapidly from 36.9% to 3.3% on day 3; thereafter it increased to 64.3% 21 days after delivery because of a higher baseline concentration of hCG alpha. hCG beta had the slowest total elimination rate, and the ratio of hCB beta to hCG in serum increased from 0.8% before delivery to 26.7% after 21 days. If the metabolism of hCG and hCG beta is similar in patients with trophoblastic disease, the ratio of hCG beta to hCG must be evaluated with caution in samples taken several days after initiating therapy. We conclude that the disappearance of hCG beta from plasma is slower than previously recognized and that the ratios of hCG beta or hCG alpha to intact hCG vary as a function of postpartum time. Such information may be important in clinical studies of pregnancy disorders.

Immunoprocedures for detecting human chorionic gonadotropin: clinical aspects and doping control

The pregnancy hormone human chorionic gonadotropin (hCG) is also present at low concentrations in plasma and urine of men and nonpregnant women. hCG immunoreactivity occurs in various molecular forms: Besides the intact hCG heterodimer, considerable amounts of proteolytically cleaved forms, free subunits, and fragments are found in plasma and urine. Especially in urine, proteolytic fragments constitute a major part of the hCG immunoreactivity. The different forms of hCG cross-react to various degrees in immunoassays and constitute a problem for standardization of specific hCG determinations. After injection of hCG (10,000 IU of Pregnyl; Organon), above-normal concentrations of hCG can be detected in serum and urine for 7-11 days. Most immunoassays for hCG also measure hCG beta. Quantitative hCG determinations are mainly performed on serum samples, and very few commercial hCG determinations have been validated for determination of urine samples. Considerable care must therefore be exercised when utilizing such assays to analyze urines for doping control.

Pathophysiological importance of various molecular forms of human choriogonadotropin

Human chorionic gonadotropin (hCG), its subunits and fragments are widely used for diagnostic purposes. In addition to the diagnosis of pregnancy and pregnancy related disorders, hCG determinations are used for diagnosis of trophoblastic and recently also nontrophoblastic tumors. The use for diagnosis of nontrophoblastic tumors requires highly specific and ultrasensitive assays. With these, it is possible to measure the concentrations of both hCG, the free beta-subunits and the so called beta-core fragment in healthy subjects. Therefore it is important to establish reference values for these and also to be aware of the influence of physiological factors on the serum and urine concentrations. Improved standardization of the assay methods is also essential for these novel applications of hCG determinations to become useful.

Ectopic pregnancy after in-vitro fertilization is characterized by delayed implantation but a normal increase of serum human chorionic gonadotrophin and its subunits

We studied the dynamics of serum human chorionic gonadotrophin (HCG) and its free alpha (HCG alpha) and beta (HCG beta) subunits in 49 early pregnancies achieved by in-vitro fertilization (IVF) and embryo transfer. Of the 49 early pregnancies, nine were normal singleton pregnancies, 11 were twin pregnancies, 11 were ectopic, eight ended in a clinical (spontaneous) abortion and 10 ended in a preclinical abortion. The HCG, HCG alpha and HCG beta concentrations in serum were measured on days 12, 19 and 26 after embryo transfer. Most ectopic pregnancies could be distinguished from singleton (and twin) pregnancies on the basis of low HCG concentrations by 12 days after embryo transfer, but clinical abortions could not be distinguished from singleton pregnancies. In general, the measurement of HCG alpha and HCG beta and the molar ratios of the various forms provided only marginal additional value to that obtained from HCG, but on days 19 and 26 after embryo transfer HCG alpha was the most sensitive indicator of a normal pregnancy after IVF and embryo transfer. We conclude that in ectopic pregnancies the concentrations of HCG, HCG alpha and HCG beta increase as expected but 1.5 days later than in normal pregnancies. This appears to be the result of a delay in implantation.

Independent prognostic value of preoperative serum markers CA 242, specific tissue polypeptide antigen and human chorionic gonadotrophin beta, but not of carcinoembryonic antigen or tissue polypeptide antigen in colorectal cancer

The prognostic value of preoperative serum concentrations of carcinoembryonic antigen (CEA), CA 242, tissue polypeptide antigen (TPA), specific tissue polypeptide antigen (TPS) and human chorionic gonadotrophin beta (hCG beta) in 251 patients with colorectal cancer (39 Dukes' A, 98 Dukes' B, 56 Dukes' C and 58 Dukes' D) was investigated. When using the cut-off levels recommended for diagnostic purposes, there was a significantly longer overall survival in patients with low tumour marker levels compared with patients with elevated serum levels for all the investigated markers. In Dukes' stage B, C and D CA 242 emerged as a significant predictor of survival, whereas TPA, TPS and hCG beta showed a value only in Dukes' D. Unfortunately, no marker provided prognostic information in Dukes' A. In multivariate analysis, entering the tumour markers as continuous variables, Dukes' stage was the strongest prognostic factor, followed by CA 242. TPS, hCG beta and localisation of the tumour were also independent prognostic factors, whereas age, gender, CEA and TPA were not.

Increase in first morning voided urinary luteinizing hormone levels precedes the physical onset of puberty

Determinations of serum gonadotropin concentrations by ultra-sensitive methods have improved the diagnosis of pubertal disorders. The onset of puberty can be estimated by measuring serum gonadotropin pulsation, but as this requires serial nocturnal blood sampling, it is not a routine investigation. Gonadotropin measurements in first morning voided (FMV) urine samples could reflect the integrated nocturnal gonadotropin secretion and predict pubertal development earlier than daytime serum measurements. We studied the value of urinary LH (U-LH) measurements in FMV urine with reference to serum LH (S-LH) levels using an ultrasensitive time-resolved immunofluorometric assay in samples from 297 children and adolescents (145 boys and 152 girls, aged 5-15 yr) with known pubertal stages (Tanner 1-5). Stage 1 subjects (prepubertal) were divided into 5 age groups to assess whether there is an increase in LH before clinical signs of puberty can be detected. The correlation between FMV urine and S-LH values was good (r = 0.64; P < 0.0001). The 2 oldest groups of prepubertal subjects (11 and 12 yr) had significantly higher (P < 0.001) U-LH concentrations than the 3 younger groups. This difference was less marked for S-LH. A significant increase in FMV U-LH concentration occurs before the first clinical signs of puberty in a sex-independent fashion. Our data indicate that FMV U-LH measurement is a clinically relevant, noninvasive method for the evaluation of pubertal development, and it may be helpful in the investigation of pubertal disorders.

Failure of creatine kinase to predict ectopic pregnancy

OBJECTIVE

To investigate serum creatine kinase (CK) levels in pregnant women with ectopic pregnancy (EP), spontaneous abortion, and normal pregnancy with comparable serum hCG concentrations.

DESIGN

A retrospective, case-controlled study.

SETTING

Helsinki University Central Hospital, Helsinki, Finland.

PATIENTS

Forty-four patients with a suspicion of EP of which 15 had laparoscopically confirmed tubal pregnancies; 15 had a spontaneous abortion, a blighted ovum, or a missed abortion; and 14 patients a normal intrauterine pregnancy.

INTERVENTIONS

The diagnosis was made by transvaginal sonography and serum hCG determinations either at admission or after repeated examinations. Ectopic pregnancy was confirmed and treated by laparoscopy.

MAIN OUTCOME MEASURES

Serum CK and hCG levels.

RESULTS

No significant differences in CK levels were observed between the groups by one-way analysis of variance and no correlation was found between serum CK and hCG levels within any group.

CONCLUSIONS

Creatine kinase does not appear to be useful in the diagnosis of early EP.

Markers supplementing CA 125 in ovarian cancer

Markers supplementing CA 125 are important for monitoring of the disease in patients with mucinous and non-epithelial ovarian cancers. Tumour-associated trypsin inhibitor (TATI) or one of the gastrointestinal mucin markers, CA 19-9 or CA 72.4 are good supplements to CA 125 in mucinous ovarian cancer. Chorionic gonadotrophin (hCG) and alpha fetoprotein (AFP) are the most useful markers for germ cell tumours, and hCG beta may provide additional information. In addition to hCG beta, M-CSF and inhibin show promise of becoming useful supplements to CA 125 in ovarian cancer in general. Markers other than CA 125 may also play a role as prognostic indicators. TATI and procollagen peptides appear useful for this purpose. If these markers prove to provide reliable prognostic information, they could be used to aid selection of optimal treatment regimens.

Streptavidin-biotin based time-resolved immunofluorometric assay for direct measurement of high concentrations of human chorionic gonadotropin (hCG)

Quantitation of human chorionic gonadotropin (hCG) in maternal serum is widely used for screening of fetal trisomy-21 (Down's syndrome). When using immunometric assay, the sample usually has to be prediluted in order to quantitate the high hCG concentrations occurring during weeks 10-17 of pregnancy. Utilizing a streptavidin-biotin system we have developed an immunofluorometric assay (IFMA) for the quantitation of hCG in pregnancy serum that does not require predilution of the sample. The sample is added to a streptavidin coated microtiter strip well together with a biotinylated 'capture' antibody. About 1-2% of the capture antibody is biotinylated whereas most of the antibodies are unbiotinylated and thus unable to bind to the solid phase, while still binding antigen. This displaces the assay range from 0.5-5000 IU/l of the standard assay to 20-250,000 IU/l. The method shows good correlation with the standard procedure (r = 0.96). By eliminating a dilution step the assay procedure is both simplified and reinforced. The principle of this method should be readily applicable to other antigens and detection methods.

A clinically useful method for detecting gonadotropins in children: assessment of luteinizing hormone and follicle-stimulating hormone from urine as an alternative to serum by ultrasensitive time-resolved immunofluorometric assays

To study the feasibility of noninvasive sampling in pediatric patients, we examined the concentrations of LH and FSH in paired serum and urine samples from 65 children (age 0-15 y) with highly sensitive time-resolved immunofluorometric assays. The detection limits of the assays were 0.015 IU/L for LH and 0.018 IU/L for FSH. These sensitivity levels allowed quantification of the low prepubertal LH and FSH concentrations. The correlation between serum and urine gonadotropin values was very good (r = 0.751, p < 0.001 for FSH; and r = 0.720, p < 0.001 for LH), and the urine and serum concentrations were very similar. Correction of urinary gonadotropin concentrations for changes in urinary flow by standard methods using density [concentration x (0.02/density-1)] or creatinine (concentration/creatinine) did not improve the correlation. Therefore, measurement of urinary gonadotropins without correction can simply be used in the pediatric outpatient setting as a noninvasive alternative to serum determinations.

A new simple and rapid dual assay for AFP and free beta hCG in screening for Down syndrome

We have evaluated a simple and rapid 2-step dual-label assay (DELFIA) for alphafetoprotein (AFP) and free beta subunit of human gonadotropin (hCG beta) in second-trimester screening for Down syndrome. Based on stored serum samples from 1059 normal control pregnancies and 72 cases of Down syndrome, we have found the mean Multiple of Median (MoM) for AFP and free hCG beta to be 0.70 and 2.31, respectively. This is slightly but not significantly better than the values for the separate assay for AFP (0.76 MoM) and for intact hCG (2.11 MoM). However, the dual assay is much simpler than the separate assays and therefore prospective comparison trials should be carried out.

Simultaneous assay of alpha-fetoprotein and free beta subunit of human chorionic gonadotropin by dual-label time-resolved immunofluorometric assay

We developed a simple, rapid two-step dual-label assay for the noncompetitive determination of alpha-fetoprotein (AFP) and beta subunit of human chorionic gonadotropin (hCG beta) in serum. Monoclonal antibodies to detect AFP and hCG beta were labeled with europium (Eu) and samarium (Sm), respectively. Highly fluorescent chelates were developed by using the Delfia enhancement principle. The detection limits for AFP and hCG beta were approximately 0.02 kIU/L and approximately 0.2 IU/L, respectively. The within-run precision was < 5% over the whole range of AFP (1-500 kIU/L) and hCG beta (1-200 IU/L) concentrations tested. Cross-reaction of intact hCG was < 0.03%. The AFP concentrations determined with the dual-label assay correlated well with those obtained by Delfia AFP single-label kit. The concentrations of hCG beta were in good agreement with recently published data. Storing the serum samples for 24 h or 1 week at room temperature increased the hCG beta concentration by 4% and 26%, respectively. At 35 degrees C this dissociation of hCG increased 30-40-fold. Repeated freezing and thawing had no effect on the hCG beta concentration.

Simultaneous assay of alpha-fetoprotein and free beta subunit of human chorionic gonadotropin by dual-label time-resolved immunofluorometric assay

We developed a simple, rapid two-step dual-label assay for the noncompetitive determination of alpha-fetoprotein (AFP) and beta subunit of human chorionic gonadotropin (hCG beta) in serum. Monoclonal antibodies to detect AFP and hCG beta were labeled with europium (Eu) and samarium (Sm), respectively. Highly fluorescent chelates were developed by using the Delfia enhancement principle. The detection limits for AFP and hCG beta were approximately 0.02 kIU/L and approximately 0.2 IU/L, respectively. The within-run precision was &lt; 5% over the whole range of AFP (1-500 kIU/L) and hCG beta (1-200 IU/L) concentrations tested. Cross-reaction of intact hCG was &lt; 0.03%. The AFP concentrations determined with the dual-label assay correlated well with those obtained by Delfia AFP single-label kit. The concentrations of hCG beta were in good agreement with recently published data. Storing the serum samples for 24 h or 1 week at room temperature increased the hCG beta concentration by 4% and 26%, respectively. At 35 degrees C this dissociation of hCG increased 30-40-fold. Repeated freezing and thawing had no effect on the hCG beta concentration.

Absence of autoantibodies to human chorionic gonadotropin in women with a history of habitual abortion

OBJECTIVE

To determine if immunization to human chorionic gonadotropin (hCG) has occurred in women with habitual abortion.

DESIGN

Comparisons between nonpregnant patients with a history of at least three consecutive miscarriages (n = 48) and normal controls (n = 38). In addition, 28 habitual aborters were compared, while pregnant, with 37 pregnant control women. Antibodies to hCG were assessed by a solid-phase immunometric assay using europium-labeled antihuman immunoglobulin (Ig)G as tracer; this method is capable of detecting antibodies toward hCG in serum of patients immunized with beta-hCG-tetanus toxoid conjugate.

SETTING

Departments I and II of Obstetrics and Gynecology, University Central Hospital of Helsinki, Helsinki, Finland.

RESULTS

Three patients (1 primary and 2 secondary aborters, 1 both while pregnant and not pregnant) showed evidence of Ig binding to hCG, but the binding was not inhibited by an excess of hCG.

CONCLUSIONS

Antibodies against endogenous hCG may not be responsible for habitual abortion.

Concentrations of Human Choriogonadotropin, Its β-Subunit, and the Core Fragment of the β-Subunit in Serum and Urine of Men and Nonpregnant Women

Sensitive, specific time-resolved immunofluorometric assays were used to measure the concentrations of human choriogonadotropin (hCG), free beta-subunit (beta-hCG), and the core fragment of beta-hCG (c beta-hCG) in serum and urine of men and nonpregnant women without evidence of cancer. Concentrations of hCG and beta-hCG were measurable in 59-70% of serum samples and in 50-59% of urine samples. c beta-hCG was mostly undetectable in serum but measurable in 81% of urine samples. Concentrations were higher in women than in men, and hCG concentrations increased with age. Therefore, reference ranges based on the 97.5 percentile were calculated separately for women and men and for those &lt; 50 and &gt; 50 years. However, concentrations of hCG correlated much more strongly with those of follicle-stimulating hormone than with age. hCG concentrations in serum were similar to those reported before, but beta-hCG concentrations were below the detection limit of earlier assays, and the upper reference limit was one-fifth to one-tenth the cutoff concentrations used earlier. In urine, hCG and c beta-hCG were the major forms of hCG, and their concentrations were similar to those of hCG in serum.

Concentrations of human choriogonadotropin, its beta-subunit, and the core fragment of the beta-subunit in serum and urine of men and nonpregnant women

Sensitive, specific time-resolved immunofluorometric assays were used to measure the concentrations of human choriogonadotropin (hCG), free beta-subunit (beta-hCG), and the core fragment of beta-hCG (c beta-hCG) in serum and urine of men and nonpregnant women without evidence of cancer. Concentrations of hCG and beta-hCG were measurable in 59-70% of serum samples and in 50-59% of urine samples. c beta-hCG was mostly undetectable in serum but measurable in 81% of urine samples. Concentrations were higher in women than in men, and hCG concentrations increased with age. Therefore, reference ranges based on the 97.5 percentile were calculated separately for women and men and for those < 50 and > 50 years. However, concentrations of hCG correlated much more strongly with those of follicle-stimulating hormone than with age. hCG concentrations in serum were similar to those reported before, but beta-hCG concentrations were below the detection limit of earlier assays, and the upper reference limit was one-fifth to one-tenth the cutoff concentrations used earlier. In urine, hCG and c beta-hCG were the major forms of hCG, and their concentrations were similar to those of hCG in serum.

Elevation of free beta subunit of human choriogonadotropin and core beta fragment of human choriogonadotropin in the serum and urine of patients with malignant pancreatic and biliary disease

Human choriogonadotropin (hCG), its free beta subunit (beta hCG), and the core beta hCG fragment (c beta hCG) were measured by highly sensitive time-resolved immunofluorometric assays in the serum and urine of 29 patients with pancreatic cancer, 7 patients with biliary cancer, and 45 patients with benign pancreatic or biliary diseases. The results were compared with those of an age- and sex-matched reference population of nonpregnant women and men. Of the various forms of hCG assayed in serum, beta hCG showed the best diagnostic accuracy, and c beta hCG was the best marker in urine. Elevated serum concentrations of beta hCG were observed in 72% of the patients with pancreatic cancer, in 6 of 7 patients with biliary cancer, and in 9% of those with benign disorders. The serum concentrations of c beta hCG were elevated in 45%, 57%, and 2%, respectively, and those in urine in 55%, 71%, and 11%, respectively. The molar concentrations of c beta hCG in serum were mostly lower than those of beta hCG. Thus beta hCG secreted into serum appears to be the main source of c beta hCG in urine. Provided that they are measured by sufficiently sensitive and specific assays, beta hCG in serum and c beta hCG in urine appear to be useful markers for pancreatic and biliary cancer.

Developmental changes in 24-hour profiles of luteinizing hormone and follicle-stimulating hormone from prepuberty to midstages of puberty in boys

To establish the pubertal changes in gonadotropin secretion, 24-h secretory profiles of LH and FSH were studied in 10 healthy boys by ultrasensitive (sensitivity, 0.019 and 0.014 IU/L, respectively) time-resolved immunofluorometric assays 21 times. Five of the 10 boys were sampled on 2-6 occasions over a time interval of 0.95-6.4 yr. When sampled, 6 boys were prepubertal (testicular volume, less than 3 mL), 8 boys were early pubertal (testicular volume, 3-5 mL), and 7 boys were midpubertal (testicular volume, 10-25 mL). Plasma was taken every 20 min for 24 h. All boys had LH and FSH pulses. In prepuberty, the mean LH level was much lower than the mean FSH level, and neither showed significant diurnal variation. In early puberty, the mean LH level increased much more than that of FSH. For LH, the increase in mean levels was due to an increase in both pulse amplitude and frequency. During early and midpuberty, these changes were most marked at night, leading to the appearance of diurnal variation. For FSH, the mean levels increased progressively from prepuberty to midpuberty, with a slight increase in the mean pulse amplitude at the onset of puberty, whereas no change in pulse frequency was found. In contrast to LH, no diurnal variation was found for FSH at any of the pubertal stages. Thus, at the onset of puberty, gonadotropin secretion undergoes specific changes, which are different for LH and FSH, involving changes in pulse amplitudes and frequencies and development of diurnal variation for LH.

A complex between prostate-specific antigen and alpha 1-antichymotrypsin is the major form of prostate-specific antigen in serum of patients with prostatic cancer: assay of the complex improves clinical sensitivity for cancer

We have studied the forms of prostate-specific antigen (PSA) in serum of patients with prostatic cancer and benign prostatic hyperplasia. Fractionation of serum by gel filtration and assay of the fractions for PSA showed that a considerable part of the PSA immunoreactivity in serum consisted of complexes that were larger than PSA. The complexes were assayed by time-resolved immunofluorometric assays based on an antibody against PSA on the solid phase and europium-labeled antibodies against various protease inhibitors as indicator antibodies. In addition to its monomeric form, PSA was found to occur in complex with alpha 1-antichymotrypsin. The proportion of the alpha 1-antichymotrypsin complex was a major form of PSA and it increased with increasing PSA concentrations, being over 85% at PSA levels exceeding 1000 micrograms/liter. A complex with alpha 1-protease inhibitor was also observed in serum of patients with prostatic cancer and very high levels of PSA. Complexes with alpha 2-macroglobulin and inter-alpha-trypsin inhibitor were detected, but their concentrations were low and similar in sera of cancer patients, normal men, and normal women, suggesting that they were not prostate derived. Commercial immunoradiometric assays for PSA were found to measure free PSA and its complexes with alpha 1-antichymotrypsin but not the complexes with alpha 2-macroglobulin and inter-alpha-trypsin inhibitor. The proportion of the PSA-alpha 1-antichymotrypsin complex was higher in patients with prostatic cancer than in those with benign hyperplasia. Therefore, assay of the complex had a higher sensitivity for cancer than assay of total PSA immunoreactivity.

Method dependence of interpretation of immunoassay results

The interpretation of results obtained by immunoassays is affected by many different factors and especially by assay sensitivity and specificity. The introduction of sandwich-type immunometric assays using highly sensitive non-radioactive labels and monoclonal antibodies has greatly improved sensitivity while reducing assay time and simplifying performance. Thus determination of subnormal levels of several hormones has become possible. This approach has also enabled more exact tuning of specificity but at the same time it has introduced the risk of too high selectivity. Hapten assays have also become simpler to perform, but in this case no substantial improvement in assay sensitivity has been achieved.

Interference by human anti-mouse antibodies in CA 125 assay after immunoscintigraphy: anti-idiotypic antibodies not neutralized by mouse IgG but removed by chromatography

Falsely increased concentrations of the ovarian carcinoma-associated antigen, CA 125, were measured by a monoclonal antibody (MAb)-based double determinant immunoradiometric assay (IRMA) in patients who developed antibodies to mouse immunoglobulins (IgGs) after receiving injections of the same MAb as is used in the CA 125 IRMA. Addition of undiluted mouse serum or purified mouse IgG to the assay mixture failed to eliminate the falsely increased CA 125 concentrations in most of the samples, owing to the presence of anti-idiotype antibody. Because of their anti-idiotypic nature, the human anti-mouse antibodies (HAMAS) had only little effect on other immunometric assays, and this effect could be completely eliminated by addition of mouse IgG. To eliminate the effect of HAMA on the CA 125 assay, we studied the ability of various chromatographic methods to separate the interfering HAMA from CA 125. For measuring HAMA in serum and chromatographic fractions we developed a time-resolved fluoroimmunoassay. Adequate separation of CA 125 and HAMA was achieved by affinity chromatography of patients' sera with solid-phase Protein A, Protein G, cation-exchange chromatography on Mono S, and gel filtration on Superose 6. These results demonstrate that the interference can effectively be removed by rather simple chromatographic procedures.

Interference by human anti-mouse antibodies in CA 125 assay after immunoscintigraphy: anti-idiotypic antibodies not neutralized by mouse IgG but removed by chromatography

Falsely increased concentrations of the ovarian carcinoma-associated antigen, CA 125, were measured by a monoclonal antibody (MAb)-based double determinant immunoradiometric assay (IRMA) in patients who developed antibodies to mouse immunoglobulins (IgGs) after receiving injections of the same MAb as is used in the CA 125 IRMA. Addition of undiluted mouse serum or purified mouse IgG to the assay mixture failed to eliminate the falsely increased CA 125 concentrations in most of the samples, owing to the presence of anti-idiotype antibody. Because of their anti-idiotypic nature, the human anti-mouse antibodies (HAMAS) had only little effect on other immunometric assays, and this effect could be completely eliminated by addition of mouse IgG. To eliminate the effect of HAMA on the CA 125 assay, we studied the ability of various chromatographic methods to separate the interfering HAMA from CA 125. For measuring HAMA in serum and chromatographic fractions we developed a time-resolved fluoroimmunoassay. Adequate separation of CA 125 and HAMA was achieved by affinity chromatography of patients' sera with solid-phase Protein A, Protein G, cation-exchange chromatography on Mono S, and gel filtration on Superose 6. These results demonstrate that the interference can effectively be removed by rather simple chromatographic procedures.

Time-resolved immunofluorometric assays for trypsinogen-1 and 2 in serum reveal preferential elevation of trypsinogen-2 in pancreatitis

We have developed sensitive time-resolved immunofluorometric assays for the two trypsinogen isoenzymes, trypsinogen-1 and trypsinogen-2, which also are called cationic and anionic trypsinogen, respectively. The assays use monoclonal antibodies produced by immunization with tumor-associated trypsinogen that is isolated from mucinous ovarian cyst fluid. In each assay, one antibody is immobilized onto the walls of polystyrene microtiter strip wells and the other is labeled with an europium(III) chelate. The cross-reaction of each trypsinogen isoenzyme in the assay for the other isoenzyme is less than 1%. The detection limits are 0.1 micrograms/L for trypsinogen-1 and 0.3 micrograms/L for trypsinogen-2. In sera of healthy subjects and patients with extrapancreatic disease the concentration of trypsinogen-1 is higher (median, 21 micrograms/L) than that of trypsinogen-2 (median, 17 micrograms/L), but in acute pancreatitis the ratio is reversed. In acute pancreatitis the concentration of trypsinogen-2 is 50-fold higher than in controls, whereas the difference in trypsinogen-1 concentrations is only 15-fold. The corresponding difference in immunoreactive trypsin measured by a commercially available radioimmunoassay was also only 10-fold.

Interference with ovulation by sequential treatment with the antiprogesterone RU486 and synthetic progestin

Seven healthy women were treated with the antiprogesterone RU486, 25 mg/d, on days 1 to 14 of the follicular phase of the menstrual cycle, followed by the synthetic progestin NET in the luteal phase of the cycle. Venous blood samples were collected twice per week. Serum E2, P, and RU486 concentrations were determined by RIAs, and FSH and LH by immunofluorometric assays. Ultrasonography was used to measure the sizes of the follicles. Serum concentrations of FSH and LH were not suppressed during the treatment. Ovulation was apparently suppressed during RU486 treatment according to E2 and P concentrations and ultrasonography findings. During NET treatment, some evidence of ovulation and follicle growth were found during the first treatment periods. During the third treatment cycle, there was no evidence of ovulation (n = 2). Estradiol concentrations were sufficient to stimulate normal proliferative growth of the endometrium during the treatment. Control of bleeding was good. The exact mechanism of action of RU486 on steroid synthesis and ovulation is not clear, but it appears to act at the ovarian level. The evidence indicates that sequential RU486/progestin treatment could be developed to result in suppression of follicular growth and ovulation.

Pulsatile secretion of LH and FSH in prepubertal and early pubertal boys revealed by ultrasensitive time-resolved immunofluorometric assays

Pulsatile secretion of LH and FSH was examined in 10 prepubertal (aged 4.5-12.9 y) and seven early pubertal (aged 12.8-14.5 y) boys with ultrasensitive (0.019 and 0.014 IU/L) time-resolved immunofluorometric assays. Plasma LH and FSH levels were measured every 15 or 20 min for 6 h during the day and night. The lowest mean LH level in a prepubertal boy was 0.02 IU/L and in eight other prepubertal boys mean LH levels were less than 0.4 IU/L. In early pubertal boys the mean LH levels ranged from 0.3 to 6.5 IU/L. The difference in mean FSH level between prepubertal (0.61 IU/L) and early pubertal boys (1.85 IU/L) was smaller than the difference in LH level. All boys had significant LH and FSH pulses. The LH interpulse interval was 135 +/- 86 min (mean +/- SD) and 76 +/- 65 min for the prepubertal and pubertal boys, respectively (p less than 0.01). For FSH, the respective values were 150 +/- 122 and 221 +/- 157 min (p = NS). The mean LH pulse amplitudes were 11-fold greater in the early pubertal boys than in the prepubertal boys, whereas the mean FSH pulse amplitudes were similar between the two groups. The present method shows that the mean LH levels in prepubertal boys are much lower, and the increase during puberty larger, than previously reported. The increase is apparently due to increased pulse frequency and amplitude. The increase in mean FSH level is smaller and evidently not caused by an increase in pulse frequency or pulse amplitude.

Pregnancy serum contains the beta-core fragment of human choriogonadotropin

We have developed a time-resolved immunofluorometric assay (IFMA) for quantification of the core fragment of the beta-subunit (c beta hCG) of hCG. The assay uses two monoclonal antibodies. One antibody is immobilized onto the wall of a microtiter strip well, and the other one is labeled with a europium chelate. The assay is sensitive (0.44 pmol/L = 4.6 ng/L), but cross-reaction with free beta-subunits of hCG (beta hCG) prevents direct determination of c beta hCG in serum. To circumvent this limitation we separated hCG and beta hCG from c beta hCG by gel chromatography and quantified each component in the fractions by specific IFMAs. The high sensitivity of the newly developed IFMA enabled us to demonstrate that serum from pregnant women contains c beta hCG and elutes at the same position in gel chromatography as c beta hCG purified from urine. The proportion of c beta hCG to hCG in pregnancy serum was 0.012-0.045% (mean +/- SD, 0.028 +/- 0.01) on a molar basis. Our finding of c beta hCG in serum confirms earlier reports suggesting that proteolytic degradation of beta hCG in the kidneys may not be the only pathway by which c beta hCG is formed.