Diagnostic accuracy of serum insulin-like growth factor-binding protein 2 for ovarian cancer.

INTRODUCTION: Insulin-like growth factor-binding protein 2 (IGFBP2) plays an important role in the pathogenesis of ovarian cancer. The most prominent effects of IGFBP2 include promoting proliferation, driving invasion, and suppressing apoptosis. This study aimed to determine the diagnostic accuracy of serum IGFBP2 in differentiating between benign and malignant ovarian neoplasms. METHODS: Preoperative serum IGFBP2 level was evaluated from 76 women with primary ovarian tumor who underwent exploratory laparotomy at Sanglah General Hospital, Denpasar, Bali, Indonesia. The optimal threshold value of IGFBP2 for the diagnosis of ovarian cancer was determined from the receiver 0perating characteristic (ROC) curve. The diagnosis was confirmed by histopathologic analysis of resected ovarian specimens. RESULTS: Forty-six (60.5%) patients were diagnosed with ovarian cancer. The area under the ROC curve (AUC) of IGFBP2 in detecting ovarian cancer was 0.815 (95% CI: 0.721 to 0.910, P<0.001). For a given specificity larger than 95%, the optimal sensitivity was 63%. The optimal threshold value of IGFBP2 for the diagnosis of ovarian cancer was 804 ng/mL [sensitivity 63%, specificity 96.7%, positive predictive value (PPV) 96.7%, negative predictive value (NPV) 63%, accuracy 76.3%, and diagnostic odd ratio (DOR) 49.5 (95% CI 6.1 to 396.5)]. In a subgroup analysis, IGFBP2 showed excellence performance in diagnosing advanced ovarian cancer (AUC 0.904 [95% CI: 0.806 to 1.000], sensitivity 83.3%, specificity 96.7%, PPV 95.2%, NPV 87.9%, accuracy 90.7%, and DOR 145.0 [95% CI 15.0 to 1395.3]). CONCLUSION: IGFBP2 is a novel and potentially promising biomarker for detecting ovarian cancer. Further studies are needed to confirm its diagnostic performance in premenopausal women and for detecting early stage ovarian cancer.

Differences in genetic variation in antigen-processing machinery components and association with cervical carcinoma risk in two Indonesian populations.

Genetic variation of antigen-processing machinery (APM) components has been shown to be associated with cervical carcinoma risk and outcome in a genetically homogeneous Dutch population. However, the role of APM component single nucleotide polymorphisms (SNPs) in genetically heterogeneous populations with different distributions of human papillomavirus (HPV) subtypes remains unclear. Eleven non-synonymous, coding SNPs in the TAP1, TAP2, LMP2, LMP7 and ERAP1 genes were genotyped in cervical carcinoma patients and healthy controls from two distinct Indonesian populations (Balinese and Javanese). Individual genotype and allele distributions were investigated using single-marker analysis, and combined SNP effects were assessed by haplotype construction and haplotype interaction analysis. Allele distribution patterns in Bali and Java differed in relation to cervical carcinoma risk, with four ERAP1 SNPs and one TAP2 SNP in the Javanese population showing significant association with cervical carcinoma risk, while in the Balinese population, only one TAP2 SNP showed this association. Multimarker analysis demonstrated that in the Javanese patients, one specific haplotype, consisting of the ERAP1-575 locus on chromosome 5 and the TAP2-379 and TAP2-651 loci on chromosome 6, was significantly associated with cervical carcinoma risk (global P = 0.008); no significant haplotype associations were found in the Balinese population. These data indicate not only that genetic variation in APM component genes is associated with cervical carcinoma risk in Indonesia but also that the patterns of association differ depending on background genetic composition and possibly on differences in HPV type distribution.

Single-visit approach of cervical cancer screening: see and treat in Indonesia.

BACKGROUND: We performed a cross-sectional study in Indonesia to evaluate the performance of a single-visit approach of cervical cancer screening, using visual inspection with acetic acid (VIA), histology and cryotherapy in low-resource settings. METHODS: Women having limited access to health-care facilities were screened by trained doctors using VIA. If the test was positive, biopsies were taken and when eligible, women were directly treated with cryotherapy. Follow-up was performed with VIA and cytology after 6 months. When cervical cancer was suspected or diagnosed, women were referred. The positivity rate, positive predictive value (PPV) and approximate specificity of the VIA test were calculated. The detection rate for cervical lesions was given. RESULTS: Screening results were completed in 22 040 women, of whom 92.7% had never been screened. Visual inspection with acetic acid was positive in 4.4%. The PPV of VIA to detect CIN I or greater and CIN II or greater was 58.7% and 29.7%, respectively. The approximate specificity was 98.1%, and the detection rate for CIN I or greater was 2.6%. CONCLUSION: The single-visit approach cervical cancer screening performed well, showing See and Treat is a promising way to reduce cervical cancer in Indonesia.

Serological markers of hepatitis B, C, and E viruses and human immunodeficiency virus type-1 infections in pregnant women in Bali, Indonesia.

Except for hepatitis B virus (HBV), there have been few data on serological markers of hepatitis viruses such as hepatitis C virus (HCV) and E virus (HEV), and human immunodeficiency virus type-1 (HIV) in Bali, Indonesia. During 5 months from April to August 2003, sera were collected from 2,450 pregnant women at eight jurisdictions in Bali, and they were tested for markers of these viruses. Only one (0.04%) was positive for antibody to HCV, but none for antibody to HIV. Hepatitis B surface antigen (HBsAg) was detected in 46 (1.9%) at a prevalence significantly lower than that in 271 of the 10,526 (2.6%) pregnant women in Bali surveyed 10 years previously (P < 0.045). The prevalence of hepatitis B e antigen in pregnant women with HBsAg decreased, also, from 50% to 28% during the 10 years (P < 0.011). Antibody to HEV (anti-HEV) was examined in 819 pregnant women who had been randomly selected from the 2,450. The overall prevalence of anti-HEV was 18%, and there were substantial regional differences spanning from 5% at Tabanan district to 32% at Gianyar district. Furthermore, the prevalence of anti-HEV differed substantially by their religions. In the Sanglah area of Denpasar City, for instance, anti-HEV was detected in 20 of the 102 (20%) Hindus, significantly more frequently than in only 2 of the 101 (2.0%) Muslims (P < 0.001). Swine that are prohibited to Muslims, therefore, is likely to serve as a reservoir of HEV in Bali. In conclusion, HBV is decreasing, HCV and HIV have not prevailed, as yet, while HEV is endemic probably through zoonotic infection in Bali.

Arachidonate transfer between platelets and lipoproteins.

Although platelets have specific bindingsites for LDL and HDL, it is doubtful whether lipoproteins modulate platelet functions via receptor-mediated processes. We investigated platelet-lipoprotein interaction during prolonged incubation with concentrations of LDL and HDL that saturate the bindingsites within a few minutes. When [3H]arachidonate-labeled human platelets were incubated for 4 h with lipoproteins, part of the 3H-radioactivity transferred to LDL and to a lesser extent to HDL. The transfer was temperature-sensitive, unaffected by modification of lysine in LDL or indomethacin treatment of the platelets, and almost irreversible. [3H]arachidonate transfer to lipoproteins could be mimicked by incubating platelets with a high concentration of fatty acid free albumin. This showed, that the loss of 3H-radioactivity reflected a decrease in endogenous arachidonate, leading to impaired aggregation, secretion and thromboxane B2 formation in platelets after stimulation with thrombin but not with arachidonate. Thus, the decrease in platelet functions seen after long incubation with HDL is caused by depletion of platelet arachidonate. Despite an even stronger arachidonate depletion by LDL, this lipoprotein initiated arachidonate metabolism and secretion independent of specific binding sites for LDL on the platelet. Surprisingly, the major part of the secretion was preserved when the formation of prostaglandin endoperoxides/thromboxane A2 was inhibited with indomethacin. These findings argue against a role for LDL and HDL receptors in the modulation of platelet functions and are more in favor of lipid exchange processes between platelets and lipoproteins.

Enhancement of platelet functions by low density lipoproteins.

Platelet suspensions, that secreted about 50% of their dense granule contents upon stimulation with alpha-thrombin, showed a dose-dependent increase in secretion after 30 min preincubation with 0.5-3.0 g low density lipoprotein (LDL) protein/1. A 1-5 min preincubation had no effect. The enhancement by LDL only occurred at about 20% secretion or more, indicating that a minimal degree of activation was required for LDL to become effective. Lysine-modified LDL was equally effective as native LDL. The effect of LDL on secretion was accompanied by enhanced thromboxane B2 formation caused by stimulation of the liberation of arachidonate from phosphatidylcholine and/or phosphatidylinositol. However, when thromboxane formation was inhibited or the prostaglandin H2-thromboxane A2-receptor was blocked, LDL remained a potent stimulator of the secretion response. Thus, LDL enhances platelet secretion by a thromboxane A2-dependent and a thromboxane A2-independent mechanism via an effect that is independent of specific binding sites on the platelet.

Abnormal platelet functions in a patient with abetalipoproteinemia.

Studies with isolated lipoproteins and washed platelets suggest that lipoproteins may affect platelet functions. We investigated platelet-rich plasma (PRP) from a patient with abetalipoproteinemia (ABL), whose plasma lacks apo-B containing lipoproteins (VLDL, LDL and chylomicrons). ABL-PRP aggregated poorly with different agonists and failed to respond to arachidonate. Thromboxane B2 (TxB2) formation was severely impaired. After gel-filtration most of the aggregation defects persisted in agreement with reduced metabolism of endogenous arachidonate. However, arachidonate-induced aggregation and TxB2 production partially normalized. Normal platelets suspended in ABL-plasma showed similar defects in aggregation and TxB2 production but arachidonate-induced aggregation was much lower than expected on the basis of TxB2. We conclude that the abnormal platelet functions in ABL-PRP are caused by (i) an intrinsic platelet abnormality due to reduced arachidonate mobilization and (ii) a property in ABL plasma that inhibits aggregation partially by trapping the arachidonate and partially by an unidentified mechanism. The latter properties may be the result of the abnormal lipid composition of ABL-plasma.

PAF-acetylhydrolase, predominantly present in LDL in healthy subjects, is associated with HDL in a patient with LDL deficiency.

The degradation of platelet-activating factor (PAF) in plasma is catalyzed by PAF-acetylhydrolase resulting in lyso-PAF which is biologically inactive. Normally, most of the PAF-degrading activity is associated with low-density lipoproteins (LDL). The enzyme activity was measured in the plasma of a patient with abetalipoproteinemia, a disorder characterized by the absence of apolipoprotein-B-containing lipoproteins (chylomicrons, VLDL and LDL). Here we report that the plasma of the patient has a normal activity of PAF-acetylhydrolase. The enzyme activity is bound to high-density lipoproteins (HDL) and shows the kinetic properties of the LDL-associated enzyme of healthy subjects. Following administration of artificial triglyceride-rich particles (ATRP), part of the enzyme activity is found associated with ATRP, indicating that PAF-acetylhydrolase can transfer from HDL to triglyceride-containing lipid complexes in vivo.

Isolation and characterization of a precursor form of lysosomal alpha-glucosidase from human urine.

A two-step procedure is described for the isolation of lysosomal alpha-glucosidase from human urine. In the second step, affinity chromatography on Sephadex G-100, two fractions with acid alpha-glucosidase activity were obtained. Fraction I contained alpha-glucosidase of Mr 109000, whereas fraction II contained components of Mr 76000 and 70000. alpha-Glucosidase in fraction I had an Mr similar to that of the precursor of alpha-glucosidase detected in the medium of fibroblasts after labelling with [14C]leucine. The components in fraction II had Mr identical to those of the mature forms of alpha-glucosidase found in placenta or cultured human skin fibroblasts. alpha-Glucosidase in fraction I contained mannose 6-phosphate (3.5 mol/mol polypeptide). No mannose 6-phosphate was present in the components in fraction II. Fraction I, but not fraction II, was avidly endocytosed by alpha-glucosidase-deficient cultured human skin fibroblasts. Endocytosis of fraction I was inhibited by mannose 6-phosphate. The pH optimum and Km values for p-nitrophenyl alpha-glucoside, maltose and glycogen of fractions I and II alpha-glucosidase were almost identical. However, the activity with glycogen relative to that of either p-nitrophenyl alpha-glucoside or maltose was lower in fraction I than in fraction II. It is concluded that fraction I consists of the precursor form of alpha-glucosidase and fraction II of the mature forms of the enzyme. The importance of urine as a source of precursors of lysosomal enzymes is discussed.

Use of a monoclonal antibody to distinguish between precursor and mature forms of human lysosomal alpha-glucosidase.

The maturation of lysosomal alpha-glucosidase in cultured human skin fibroblasts was studied using a monoclonal antibody that distinguishes between the precursor and mature forms of the enzyme. Monoclonal antibodies against alpha-glucosidase isolated from placenta were produced by the hybridoma technique [Hilkens et al. (1981) Biochim. Biophys. Acta 678, 7-11]. One of these monoclonal antibodies, that synthesized by clone 43G8, reacts with the mature forms, but not with the precursor form of alpha-glucosidase isolated from urine. By means of pulse-labelling studies, it could be shown that monoclonal antibody 43G8 does not react with either the intracellular or the secreted precursor of alpha-glucosidase from cultured human skin fibroblasts. However, the antibody does react with the intermediate and mature forms of alpha-glucosidase. Endocytosis of the precurosor of alpha-glucosidase from urine by fibroblasts is followed by its conversion to a form with lower molecular mass. After endocytosis urinary precursor alpha-glucosidase is converted to a form that binds to monoclonal antibody 43G8. The t 1/2 for this conversion is 2 h. The conversion is inhibited by addition of leupeptin to the culture medium. It is concluded that a thiol proteinase is involved in the maturation of alpha-glucosidase in fibroblasts and the appearance of the antigenic determinant for 43G8.