Diagnostic yield of chromosomal microarray analysis in fetuses with isolated increased nuchal translucency: a French multicenter study

OBJECTIVE

To determine the frequency and nature of copy number variants (CNVs) identified by chromosomal microarray analysis (CMA) in a large cohort of fetuses with isolated increased nuchal translucency thickness (NT) ≥ 3.5 mm.

METHODS

This was a retrospective, multicenter study, including 11 French hospitals, of data from the period between April 2012 and December 2015. In total, 720 fetuses were analyzed by rapid aneuploidy test and the fetuses identified as euploid underwent CMA. CNVs detected were evaluated for clinical significance and classified into five groups: pathogenic CNVs; benign CNVs; CNVs predisposing to neurodevelopmental disorders; variants of uncertain significance (VOUS); and CNVs not related to the phenotype (i.e. incidental findings).

RESULTS

In 121 (16.8%) fetuses, an aneuploidy involving chromosome 13, 18 or 21 was detected by rapid aneuploidy test and the remaining 599 fetuses were euploid. Among these, 53 (8.8%) had a CNV detected by CMA: 16/599 (2.7%) were considered to be pathogenic, including 11/599 (1.8%) that were cryptic (not visible by karyotyping); 7/599 (1.2%) were CNVs predisposing to neurodevelopmental disorders; and 8/599 (1.3%) were VOUS. Additionally, there was one (0.2%) CNV that was unrelated to the reason for referral diagnosis (i.e. an incidental finding) and the remaining 21 were benign CNVs, without clinical consequence. Interestingly, we identified five genomic imbalances of the 1q21.1 or 15q11.2 regions known to be associated with congenital heart defects.

CONCLUSION

Our study demonstrates the benefit of CMA in the etiological diagnosis of fetuses with isolated increased NT. It is worth noting that most (69%) of the detected pathogenic CNVs were cryptic. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Omega-3 fatty acids predict recurrent venous thromboembolism or total mortality in elderly patients with acute venous thromboembolism

Essentials The role of omega-3 fatty acids (n-3 FAs) in recurrent venous thromboembolism (VTE) is unknown. Association of n-3 FAs with recurrent VTE or total mortality was investigated in 826 patients. Whole blood n-3 FAs were inversely correlated with recurrent VTE or total mortality. Major and non-major bleeding was not increased in patients with higher levels of n-3 FAs.

SUMMARY

Background The role of omega-3 fatty acids (n-3 FAs) in recurrent venous thromboembolism (VTE) remains unknown. Objectives To investigate the association of n-3 FAs with recurrent VTE or total mortality at 6 months and 3 years. Methods N-3 FAs were assessed in 826 patients aged ≥ 65 years, categorized into low, medium and high based on the 25th and 75th percentile. Mean follow-up was 29 months. Results At 6 months, subjects with medium (adjusted hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.22-0.62) and high n-3 FA levels (adjusted HR, 0.36; 95% CI, 0.20-0.67) were less likely to develop recurrent VTE or total mortality, compared with those with low n-3 FAs. At 3 years, medium levels (adjusted HR, 0.67; 95% CI, 0.47-0.96) were associated with lower risk of recurrent VTE or total mortality. As compared with low n-3 FAs, the adjusted sub-hazard ratio [SHR] of recurrent VTE was 0.39 (95% CI, 0.15-0.99) in patients with medium and 0.17 (95% CI, 0.03-0.82) in patients with high n-3 FAs. The cumulative incidence of recurrent VTE was lower in the medium and high n-3 FA groups as compared with the low n-3 FA groups, but seems to have worn off after 3 years. The incidence of major and non-major bleeding was not greater in the high n-3 FA group. Conclusion Higher levels of n-3 FAs were associated with a lower risk of recurrent VTE or total mortality in elderly patients with VTE, but not with greater bleeding risk.

Association between thyroid dysfunction and venous thromboembolism in the elderly: a prospective cohort study

BACKGROUND

Venous thromboembolism (VTE) and subclinical thyroid dysfunction (SCTD) are both common in elderly patients. SCTD has been related to a hypercoagulable state and an increased thromboembolic risk. However, prospective data on the relationship between SCTD and VTE are lacking.

OBJECTIVES

To investigate the relationship between SCTD and recurrent VTE (rVTE), all-cause mortality, and thrombophilic biomarkers. Patients Elderly patients with VTE were studied.

METHODS

In a prospective multicenter cohort, thyroid hormones and thrombophilic biomarkers were measured 1 year after acute VTE, as both may be influenced by acute thrombosis. We defined subclinical hypothyroidism (SHypo) as elevated thyroid-stimulating hormone (TSH) levels (4.50-19.99 mIU L(-1) ), and subclinical hyperthyroidism (SHyper) as TSH levels of < 0.45 mIU L(-1) , both with normal free thyroxine levels. Outcomes were incidence of rVTE and overall mortality during follow-up starting after the 1-year blood sampling.

RESULTS

Of 561 participants (58% with anticoagulation), 6% had SHypo and 5% had SHyper. After 20.8 months of mean follow-up, 9% developed rVTE and 10% died. The rVTE incidence rate was 7.2 (95% confidence interval [CI] 2.7-19.2) per 100 patient-years in SHypo participants, 0.0 (95% CI 0.0-7.6) in SHyper participants, and 5.9 (95% CI 4.4-7.8) in euthyroid participants. In multivariate analyses, the sub-hazard ratio for rVTE was 0.00 (95% CI 0.00-0.58) in SHyper participants and 1.50 (95% CI 0.52-4.34) in SHypo participants as compared with euthyroid participants, without increased levels of thrombophilic biomarkers. SHyper (hazard ratio [HR] 0.80, 95% CI 0.23-2.81) and SHypo (HR 0.99, 95% CI 0.30-3.29) were not associated with mortality.

CONCLUSION

In elderly patients, SHyper may be associated with lower rVTE risks. SHypo showed a non-statistically significant pattern of an association with rVTE, without increased mortality or differences in thrombophilic biomarkers.

Physical activity and risk of bleeding in elderly patients taking anticoagulants

BACKGROUND

Although the possibility of bleeding during anticoagulant treatment may limit patients from taking part in physical activity, the association between physical activity and anticoagulation-related bleeding is uncertain.

OBJECTIVES

To determine whether physical activity is associated with bleeding in elderly patients taking anticoagulants.

PATIENTS/METHODS

In a prospective multicenter cohort study of 988 patients aged ≥ 65 years receiving anticoagulants for venous thromboembolism, we assessed patients' self-reported physical activity level. The primary outcome was the time to a first major bleeding, defined as fatal bleeding, symptomatic bleeding in a critical site, or bleeding causing a fall in hemoglobin or leading to transfusions. The secondary outcome was the time to a first clinically relevant non-major bleeding. We examined the association between physical activity level and time to a first bleeding by using competing risk regression, accounting for death as a competing event. We adjusted for known bleeding risk factors and anticoagulation as a time-varying covariate.

RESULTS

During a mean follow-up of 22 months, patients with a low, moderate, and high physical activity level had an incidence of major bleeding of 11.6, 6.3, and 3.1 events per 100 patient-years and an incidence of clinically relevant non-major bleeding of 14.0, 10.3, and 7.7 events per 100 patient-years, respectively. A high physical activity level was significantly associated with a lower risk of major bleeding (adjusted sub-hazard ratio 0.40, 95% confidence interval 0.22-0.72). There was no association between physical activity and non-major bleeding.

CONCLUSIONS

A high level of physical activity is associated with a decreased risk of major bleeding in elderly patients receiving anticoagulant therapy.

Risk of falls and bleeding in elderly patients with acute venous thromboembolism

OBJECTIVE

Whether or not a high risk of falls increases the risk of bleeding in patients receiving anticoagulants remains a matter of debate.

METHODS

We conducted a prospective cohort study involving 991 patients ≥ 65 years of age who received anticoagulants for acute venous thromboembolism (VTE) at nine Swiss hospitals between September 2009 and September 2012. The study outcomes were as follows: the time to a first major episode of bleeding; and clinically relevant nonmajor bleeding. We determined the associations between the risk of falls and the time to a first episode of bleeding using competing risk regression, accounting for death as a competing event. We adjusted for known bleeding risk factors and anticoagulation as a time-varying covariate.

RESULTS

Four hundred fifty-eight of 991 patients (46%) were at high risk of falls. The mean duration of follow-up was 16.7 months. Patients at high risk of falls had a higher incidence of major bleeding (9.6 vs. 6.6 events/100 patient-years; P = 0.05) and a significantly higher incidence of clinically relevant nonmajor bleeding (16.7 vs. 8.3 events/100 patient-years; P < 0.001) than patients at low risk of falls. After adjustment, a high risk of falls was associated with clinically relevant nonmajor bleeding [subhazard ratio (SHR) = 1.74, 95% confidence interval (CI) = 1.23-2.46], but not with major bleeding (SHR = 1.24, 95% CI = 0.83-1.86).

CONCLUSION

In elderly patients who receive anticoagulants because of VTE, a high risk of falls is significantly associated with clinically relevant nonmajor bleeding, but not with major bleeding. Whether or not a high risk of falls is a reason against providing anticoagulation beyond 3 months should be based on patient preferences and the risk of VTE recurrence.

Prospective, multicenter validation of prediction scores for major bleeding in elderly patients with venous thromboembolism

BACKGROUND

The Outpatient Bleeding Risk Index (OBRI) and the Kuijer, RIETE and Kearon scores are clinical prognostic scores for bleeding in patients receiving oral anticoagulants for venous thromboembolism (VTE). We prospectively compared the performance of these scores in elderly patients with VTE.

METHODS

In a prospective multicenter Swiss cohort study, we studied 663 patients aged ≥ 65 years with acute VTE. The outcome was a first major bleeding at 90 days. We classified patients into three categories of bleeding risk (low, intermediate and high) according to each score and dichotomized patients as high vs. low or intermediate risk. We calculated the area under the receiver-operating characteristic (ROC) curve, positive predictive values and likelihood ratios for each score.

RESULTS

Overall, 28 out of 663 patients (4.2%, 95% confidence interval [CI] 2.8-6.0%) had a first major bleeding within 90 days. According to different scores, the rate of major bleeding varied from 1.9% to 2.1% in low-risk, from 4.2% to 5.0% in intermediate-risk and from 3.1% to 6.6% in high-risk patients. The discriminative power of the scores was poor to moderate, with areas under the ROC curve ranging from 0.49 to 0.60 (P = 0.21). The positive predictive values and positive likelihood ratios were low and varied from 3.1% to 6.6% and from 0.72 to 1.59, respectively.

CONCLUSION

In elderly patients with VTE, existing bleeding risk scores do not have sufficient accuracy and power to discriminate between patients with VTE who are at a high risk of short-term major bleeding and those who are not.

Prospective comparison of clinical prognostic scores in elder patients with a pulmonary embolism

BACKGROUND

The Geneva Prognostic Score (GPS), the Pulmonary Embolism Severity Index (PESI) and its simplified version (sPESI) are well-known clinical prognostic scores for a pulmonary embolism (PE).

OBJECTIVES

To compare the prognostic performance of these scores in elderly patients with a PE.

PATIENTS AND METHODS

In a multicenter Swiss cohort of elderly patients with venous thromboembolism, we prospectively studied 449 patients aged ≥ 65 years with a symptomatic PE. The outcome was 30-day overall mortality. We dichotomized patients as low vs. higher risk in all three scores using the following thresholds: GPS scores ≤ 2 vs. > 2, PESI risk classes I-II vs. III-V and sPESI scores 0 vs. ≥ 1. We compared 30-day mortality in low- vs. higher-risk patients and the areas under the receiver-operating characteristic curve (ROC).

RESULTS

Overall, 3.8% of patients (17/449) died within 30 days. The GPS classified a greater proportion of patients as low risk (92% [413/449]) than the PESI (36.3% [163/449]) and the sPESI (39.6% [178/449]) (P < 0.001 for each comparison). Low-risk patients based on the sPESI had a mortality of 0% (95% confidence interval [CI] 0-2.1%) compared with 0.6% (95% CI 0-3.4%) for low-risk patients based on the PESI and 3.4% (95% CI 1.9-5.6%) for low-risk patients based on the GPS. The areas under the ROC curves were 0.77 (95% CI 0.72-0.81), 0.76 (95% CI 0.72-0.80) and 0.71 (95% CI 0.66-0.75), respectively (P = 0.47).

CONCLUSIONS

In this cohort of elderly patients with PE, the GPS identified a higher proportion of patients as low risk but the PESI and sPESI were more accurate in predicting mortality.

[Multicenter evaluation of four homogenous LDL-cholesterol assays]

International guidelines emphasize the importance of LDL cholesterol (LDL-C) assay in the care and follow-up of patients with cardiovascular risk. Most studies and common practice use Friedewald's formula for LDL-C calculation. The accuracy of the result depends closely on the precision of the input parameters (total cholesterol, triglycerides (TG) and HDL cholesterol), and discrepancies between calculated LDL-C and measurement by reference methods appear when TG exceed 4.5 mmol/L, or in the presence of abnormal lipoproteins. These restrictions and uncertainties in calculations have prompted the recent development of direct and homogeneous methods that fit all analyzers. A multicenter evaluation of four direct assays of LDL-C (Daiichi, Denka Seiken, Kyowa, Wako) was carried out on 45 serum samples (TG below 3.1 mmol/L) in eight laboratories using different analyzers. For three methods (Daiichi, Kyowa, Wako), the interlaboratory reproducibility was markedly improved relative to that of calculation. A strong correlation was found for all new methods when compared with a beta-quantification assay. Average bias in Denka Seiken assays was greater than Kyowa's and Daiichi's (although less dispersed for the latter) and for Wako all bias were positive. The relationship between bias variations and the lipid parameters of the samples was studied. Three methods, Daiichi, Kyowa and Wako, revealed a significant positive correlation between bias and serum VLDL-C/TG ratio, clearly indicating that cholesterol enrichment of VLDL was a source of variability in these assays. Specificity of the four methods was tested in situation of dyslipidemia by spiking isolated lipoproteins (chylomicrons, VLDL and HDL). This experiment revealed differences in behavior, most evidently upon addition of VLDL. No method was truly specific, but up to 8 mmol/L of TG the variations were acceptable. In the presence of type III hyperlipoproteinemia, however, only the Denka Seiken method was reliable. Linearity up to 20 mmol/L (Daiichi, Denka Seiken) or 14 mmol/L (Kyowa, Wako) of LDL-C allows these tests to be used in main routine cases. New direct assays are an obvious technological advance in terms of analytical performance and conveniency. Their use for the diagnosis and follow-up of hyperlipidemic patients offers an alternative that overcomes the limitations of the Friedewald calculation.

Clinical significance of interobserver differences in the staging and grading of superficial bladder cancer

OBJECTIVE

To assess the reliability of the histological diagnosis of bladder cancer by assessing the interobserver variability of staging and grading in pTa/pT1 tumours and evaluating the clinical significance of discrepancies.

MATERIALS AND METHODS

All sections from 301 superficial bladder carcinomas were reviewed by one pathologist. The prognostic relevance of grade and stage from both the initial and review diagnosis were determined in 128 patients for whom there was long-term follow-up information.

RESULTS

There were significant interobserver differences in both the grading and staging of tumours. From a total of 235 tumours that were initially considered pT1, the reviewer classified 35% as pTa, 56% as pT1, 6% as pT1- (at least pT1), and 3% as pT2-4. In 39% of all biopsies there were interobserver differences in tumour grade. The prognostic significance of grade and stage differed between the initial pathology report and the reviewer's diagnosis. The reviewer's staging allowed a better estimate of the risk of subsequent tumour progression than the initial staging. Progression was significantly more common in 49 tumours in which the reviewer agreed with stage pT1 than in 29 tumours that were down-staged from pT1 to pTa (P = 0.0116). However, the initial tumour grade (P = 0.0386) but not the reviewer's grade (P = 0.2645) was significantly linked to progression.

CONCLUSIONS

These results show that grading and staging by different pathologists have varying prognostic implications. If possible, biopsies from bladder tumours should be independently evaluated by two different pathologists before radical therapy is administered.

[Multicenter evaluation on different analyzers of three methods for direct HDL-cholesterol assay]

Most frequently, in routine laboratories, C-HDL is measured in the supernatant after precipitation of apolipoprotein B-containing lipoproteins by the sodium phosphotungstate/magnesium chloride reagent (PTA). This method involves precipitation, centrifugation and decantation steps which prevent full automation of the measurement and decrease the accuracy of the results. Recently, three direct assays for C-HDL including alpha-cyclodextrin sulphate (alpha-CD), polyanions/detergents (PA-D) or antibodies anti-beta-lipoproteins (AC) have been commercialized, in which all steps are fully managed by automated analyzers. These new methods have been compared to the conventional procedure (PTA), in multicenter studies among six laboratories using different analyzers. The C-HDL values measured by the alpha-CD and PA-D assays correlated well with those of the PTA method (r > 0.98), on most of the analyzers. With the AC assay, only the results obtained with the Hitachi 717 analyzer were correlated with C-HDL values of the PTA method. The linearity and specificity studies were evaluated in the laboratory A on a Kone Specific analyzer. The alpha-CD and PA-D assays were linear for C-HDL values from 0 to 5.56 mmol/l, as observed by increasing amounts of HDL2 + HDL3 or serum without lipoprotein isolated by ultracentrifugation. The specificity of these two methods was evaluated simultaneously, by adding various amounts of lipoproteins isolated by sequential ultracentrifugation. No interference was observed when adding chylomicrons up to 13.4 mmol/l of triglycerides for both methods. Inversely, increased C-HDL values were observed with added VLDL from 6 mmol/l of triglycerides for the PA-D assay and from 8 mmol/l for the alpha-CD assay. No interference was observed with added LDL up to 11.5 mmol/l of C-LDL for the alpha-CD assay and up to 6.7 mmol/l for the PA-D assay. In conclusion, the present multicenter evaluation demonstrates that the new procedures for the direct automation of C-HDL are easy and accurate and most of them correlated well with the classical precipitation method. In addition the study provides arguments for a choice between the different direct C-HDL methods.

Interrelationships between postprandial lipoprotein B:CIII particle changes and high-density lipoprotein subpopulation profiles in mixed hyperlipoproteinemia

We studied the relationships postprandially between triglyceride-rich lipoprotein (TRL) and high-density lipoprotein (HDL) in 11 mixed hyperlipoproteinemia (MHL) and 11 hypercholesterolemia (HCL) patients. The high and prolonged postprandial triglyceridemia response observed in MHL but not HCL patients was essentially dependent on very-low-density lipoprotein (VLDL) changes. This abnormal response was related to decreased lipoprotein lipase (LPL) activity (-48.7%, P<.01) in MHL compared with HCL subjects. Cholesteryl ester transfer protein (CETP) activity was postprandially enhanced only in MHL patients, and this elevation persisted in the late period (+19% at 12 hours, P<.05), sustaining the delayed enrichment of VLDL with cholesteryl ester (CE). The late postprandial period in MHL patients was also characterized by high levels of apolipoprotein B (apoB)-containing lipoproteins with apoCIII ([LpB:CIII] +36% at 12 hours, P<.01) and decreased levels of apoCIII contained in HDL ([LpCIII-HDL] -34% at 12 hours, P<.01), reflecting probably a defective return of apoCIII from TRL toward HDL. In MHL compared with HCL patients, decreased HDL2 levels were related to both HDL2b and HDL2a subpopulations (-57% and -49%, respectively, P<.01 for both) and decreased apoA-I levels (-53%, P<.01) were equally linked to decreased HDL2 with apoA-I only (LpA-I) and HDL2 with both apoA-I and apoA-II ([LpA-I:A-II] -55% and -52%, respectively, P<.01 for both). The significant inverse correlations between the postprandial magnitude of LpB:CIII and HDL2-LpA-I and HDL2b levels in MHL patients underline the close TRL-HDL interrelationships. Our findings indicate that TRL and HDL abnormalities evidenced at fasting were postprandially amplified, tightly interrelated, and persistent during the late fed period in mixed hyperlipidemia. Thus, these fasting abnormalities are likely postprandially originated and may constitute proatherogenic lipoprotein disorders additional to the HCL in MHL patients.

Hyperalphalipoproteinemia: characterization of a cardioprotective profile associating increased high-density lipoprotein2 levels and decreased hepatic lipase activity

The aim of the present study was to investigate the high-density lipoprotein (HDL) structural characteristics and metabolism in hyperalphalipoproteinemic (HALP) patients (HDL-cholesterol [HDL-C], 92 +/- 14 mg/dL) with combined elevated low-density lipoprotein-cholesterol (LDL-C) levels (LDL-C, 181 +/- 33 mg/dL). Patients were subjected to a complete cardiovascular examination, including ultrasonographic investigation of carotid arteries. Two HALP profiles were identified according to the HDL2/HDL3 ratio. HALP profile A was characterized in 28 patients by increased HDL2/HDL3 ratio, HDL2b, and lipoprotein (Lp)A-I levels compared with normolipidemic subjects, and HALP profile B, including the 12 remaining patients, was characterized by a HDL2/HDL3 ratio within the normal range and by the increase of all HDL subclasses (HDL(2b,2a,3a,3b,3c)), LpA-I, and LpA-I:A-II levels. With regard to the exploration of carotid arteries, in HALP profile A, 20 patients were free from lesions and eight had only intimal wall thickening. In HALP profile B, only one patient was free from lesions, four had intimal wall thickening, and seven displayed plaques, but none had stenosis. Taking into account the number of patients with plaques within each group, HALP profile A was associated with a low prevalence of atherosclerotic lesions, whereas HALP profile B was less cardioprotective (odds ratio, 77.7 [95% confidence interval, 3.7 to 1,569.7]; P < .0001). For both HALP profiles, cholesteryl ester transfer protein (CETP) deficiency was discarded and activities of phospholipid transfer protein (PLTP) and lipoprotein lipase (LPL) were normal. However, hepatic lipase (HL) activity was significantly decreased in HALP profile A, but within the normal range for HALP profile B. In conclusion, an HALP profile A with a low prevalence of atherosclerosis was characterized by an increased HDL2/HDL3 ratio, HDL2b, and LpA-I levels associated with decreased HL activity.

Rapid electrophoretic separation of pre-beta-migrating high density lipoproteins using automated PhastSystem: application to analysis of lecithin:cholesterol acyltransferase-deficient plasma

To identify pre-beta-high density lipoproteins, a rapid two-dimensional separation by electrophoresis (1 hour 30 minutes) was performed on an automated Phast System. This procedure used commercially available polyacrylamide gradient gels (4-15%) and allows sensitive and reproducible results. Pre-beta-1- and pre-beta-2-high density lipoproteins were clearly identified by this method. In addition, our procedure was successfully applied to diagnosis of a patient with familial lecithin:cholesterol acyltransferase deficiency, characterized by the absence of alpha-high density lipoproteins.

Direct isolation of labeled low density lipoproteins for the determination of cholesteryl ester transfer protein activity

The measurement of the activity of cholesteryl ester transfer protein (CETP), is of high clinical interest and this study reports the use of a direct LDL isolation (d-LDL) technique to determine in one step the amount of radiolabeled cholesteryls esters ([3H]-CE) transferred from exogenous HDL3 to LDL, avoiding the conveniences of the usually used ultracentrifugation or precipitation of apo-B containing lipoproteins in the CETP methodologies. The d-LDL technique providing a specific immunoprecipitation of VLDL, IDL and HDL allowed to directly determine the [3H]-CE transferred on LDL (d-[3H]-CE-LDL). Two methodologies were assayed for the CETP activity using either exogenous or endogenous lipoproteins, and the results with the d-LDL technique were compared with those obtained using the ultracentrifugation (u-[3H]-CE-LDL) considered as the reference method. The intra- and inter-assays were similar in both techniques for the two CETP activity assays. Strong positive correlations were established between values obtained with d-[3H]-CE-LDL and u-[3H]-CE-LDL isolation procedures for CETP activities with exogenous or endogenous lipoproteins (r = 0.972; p = 0.0001 and r = 0.965; p = 0.0001 respectively). In conclusion, the d-LDL technique represents an easy and accurate procedure to measure directly, in normotriglyceridemic plasmas, the amount of [3H]-CE transferred from HDL to LDL by the CETP.

Use of confocal microscopy to localize the SHBG interaction with human breast cancer cell lines--a comparison with serum albumin interaction

This work has allowed a comparison between the interaction of two principal plasma estradiol-binding proteins, serum albumin and Sex Hormone Binding Globulin (SHBG), with human breast cancer cells in culture (MCF-7 and MDA-MB 231), using a protocol which protects the integrity of cell structure. We showed that serum albumin was highly internalized by cells whereas SHBG interacted essentially at the plasma membrane level, and this whatever the contents of the receptor estrogen cells. If, by its high plasma concentration, serum albumin is internalized in a non-specific way and can thus fit into intracellular traffic, SHBG, by its membrane binding, seems to have a specific action toward target cells.

Receptor-mediated and absorptive endocytosis by male germ cells of different mammalian species

The routes for adsorptive and receptor-mediated endocytosis were studied in vivo after microinjection of tracers into the lumen of the seminiferous tubules, and in vitro in isolated germ cells of different mammals. Cationic ferritin was located on the plasma membrane, in vesicles, in tubules, in multivesicular bodies and in lysosome-like granules of mouse spermatocytes. In these cells the number of multivesicular bodies varied during spermatogenesis. Spermatids and to a lesser extent residual bodies also performed adsorptive endocytosis. In the rat and monkey (Macaca fascicularis) diferric transferrin was specifically taken up by germ cells via receptor-mediated endocytosis. The labelling was observed subsequently in membrane pits, vesicles, endosome-like bodies and pale multivesicular bodies. A progressive decrease in the frequency of the labelling of the germ cells by transferrin-gold particles was observed from spermatogonia to spermatocytes and to early spermatids, which could indicate that iron is particularly required by germ cells during the mitotic and meiotic processes. Adsorptive and receptor-mediated endocytosis therefore occurs in all classes of germ cells. These endocytic processes are most probably required for germ cell division, differentiation and metabolism.

The plasma membrane of epididymal epithelial cells has a specific receptor which binds to androgen-binding protein and sex steroid-binding protein

The binding of [3H] delta 6-testosterone photoaffinity-labelled rat androgen-binding protein (rABP) has been studied in an enriched fraction of plasma membranes of epithelial epididymal cells in immature (15 days) and adult rats (40 days). The binding was maximal in less than 30 min and more rapid at 4 degrees C than at 34 degrees C. It was calcium and pH dependent. Scatchard plots of the binding data gave curvilinear plots with two types of binding sites corresponding to a K(ass1) of 18.2 nM-1 and K(ass2) of 1.6 nM-1 (2.2 x 10(11) sites/mg protein and 5.4 x 10(11) sites/mg protein, respectively). In adult rats, only one type of binding site was found, with a K(ass) of 3.7 nM-1 (4.5 x 10(11) sites/mg protein). The number of receptors was 5-fold lower in the cauda than in the caput of the epididymis. The pretreatment of the isolated intact cells with streptozotocin induced a 45% reduction of the binding. Only unlabelled rABP and hSBP (human sex steroid-binding protein) but not other proteins (lactotransferrin, serotransferrin, asialofetuine, fetuine and bovine serum albumin) competed with the labelled ligand to bind plasma membranes. The membrane fraction was solubilized by triton X-100. Its incubation with labelled rABP and hSBP provoked the elution of the tracer as an aggregate into the void volume fraction of superose 6B mini-gel filtration columns. Structural homology between hSBP and rABP could be responsible for the common behaviour of the steroid-carrier molecules for the ABP receptor of rat epididymal epithelial cells.

Endocytosis of human sex steroid-binding protein in monkey germ cells

We investigate in this study the hypothesis of human sex steroid-binding protein hSBP internalization into germ cells in a primate model. Human SBP was purified from late-pregnancy serum and labeled either with colloidal gold particles (18 nm) or with [3H]delta 6-testosterone by photoaffinity treatment. The germ cells were isolated from sexually mature monkey testis or caput epididymis (Macaca fascicularis) by mechanical means and cell suspensions (4 x 10(6) per 100 microliters culture medium) were incubated in presence of hSBP-gold complex (60 ng/100 microliters) or hSBP-[3H]delta 6-testosterone complex (66 ng/100 microliters, 20,000 cpm) for 2, 5, 15, 45, and 60 min. The samples were processed for electron microscopy followed by autoradiographic treatment for the radiolabeled samples. Localization of the label occurred over the whole germ cell lineage whichever tracer was used. Spermatogonia, spermatocytes, spermatids, testicular and epididymal spermatozoa exhibited specific binding sites over the plasma membrane associated with clathrin-like coated pits and vesicles. At 34 degrees C, intracellular localization of the labeled ligand was found within coated vesicles, in early and late endosomes. In addition, in early spermatogenic cells, labeled ligand was detected in the nuclei and/or associated with the nuclear envelope whereas in late spermatids and residual bodies, the labeling was accumulated in multivesicular, prelysosomal structures. Quantitative analysis of the "labeled cells/total cells" ratio exhibited a negative correlation to the maturation steps, epididymal spermatozoa being the least labeled. The cellular distribution is similar with one or the other protein in the same spermatogenic cells. Unlabeled hSBP treatment prior to labeled hSBP reduced significantly the internalization. Lowering the temperature to 4 degrees C prevented endocytosis and enhanced membrane binding. EDTA pretreatment strongly decreased hSBP internalization and modified the early endocytic steps, namely, the pinching off of the coated vesicles. It is concluded that monkey germ cells are able to internalize the human sex steroid-binding protein through specific endocytic organelles. This endocytosis leads to the labeling of the nuclei in the early spermatogenic cells and of the multivesicular bodies in the late germ cells. This strongly suggests that steroid-binding proteins may be required for spermatogenesis in acting at the germ cell lineage level either by themselves or by serving as steroid transmembrane carriers.

Skinfold and body circumferences as measures of body fat patterning in a French female active population: relationships with the metabolic risk profile

Body mass index (BMI), various anthropometric indices of abdominal fat distribution and some metabolic variables (blood lipids, fasting glucose, blood pressure) were measured in 408 French-born women from an occupational population who volunteered for the study. The aim of the study was to determine the best index for describing the relationships between the body fat pattern and the metabolic risk profile. The four age-adjusted circumference ratios (waist/hip, waist/thigh, xiphoid/hip, xiphoid/thigh) showed similar associations with the metabolic variables whereas the three age-adjusted skinfold ratios (epigastric/thigh, mesogastric/thigh, hypogastric/thigh) tended to be more weakly associated with the metabolic variables, particularly with apolipoprotein (Apo) B and fasting glucose. Multiple regression analyses showed that age-adjusted BMI was significantly related to high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, Apo A and Apo B, and blood pressure, independently of abdominal fat distribution. After controlling for the effects of BMI, the waist/thigh ratio remained significantly associated to triglyceride, Apo B, fasting glucose, and systolic blood pressure, whereas the waist/hip ratio and the mesogastric/thigh skinfold ratio were significantly related only to triglyceride and systolic blood pressure independently of BMI. With the exception of triglyceride and fasting glucose, the degree of association between the metabolic variables and the abdominal fat distribution tended to be weaker than that observed with the BMI. These results emphasize the importance of the global corpulence in the levels of metabolic variables. However, all indices of abdominal fat distribution were, to varying degrees, independently associated with an unfavorable metabolic profile. Among them, the waist/thigh circumference ratio seems to be a useful indicator of the body fat pattern in women.

Internalization of human sex steroid-binding protein in the monkey epididymis

Human sex steroid-binding protein (hSBP) has been purified from late-pregnancy serum and labelled either by iodination (125I) or by photoaffinity with [3H]delta 6-testosterone. Using a micromanipulator, each labelled protein was separately injected into the lumen of epididymal tubules isolated from the head epididymis of the cynomologus monkey (Macaca fascicularis). Tubules were sampled from 3 to 90 min after the injection and processed for electron microscope autoradiography. Localization of the label occurred over the epididymal epithelium whichever tracer was used. The labelling was not randomly distributed over the different cell types constituting the epithelium, since only the 'principal cells' exhibited a silver grain count significantly greater than the background count. In these cells, labelled protein was found over endocytic organelles (coated structures, endosomes, multivesicular bodies and the trans Golgi network) and nuclei (including the nuclear envelope). Quantitative analysis demonstrated the same pattern of cellular and subcellular distribution for each tracer. Pretreatment with excess unlabelled protein significantly reduced the uptake of radioactivity by the principal cells, demonstrating the specificity of this phenomenon. This is the first study to show direct histological evidence for the internalization of hSBP in the primate epididymis, consistent with earlier immunohistochemical or biochemical localization of this protein. It is concluded that head epididymal cells are able to take up labelled hSBP across their apical membrane. The mechanism of internalization seems to involve endocytosis by the principal cells and leads to labelling of the nuclear compartment. This is strikingly similar to the pattern of uptake of rat androgen-binding protein (rABP) by rat epididymal cells previously demonstrated by our group. To what extent the chemical and structural homology between hSBP and rABP can be held responsible for the common cytophysiological behaviour of these sex steroid-binding proteins remains to be determined.

Hormonal influences on the relationships between body fatness, body fat distribution, lipids, lipoproteins, glucose and blood pressure in French working women

The independent associations between overall obesity, body fat distribution, lipids, lipoproteins, glucose, blood pressure and some hormonal factors (sex hormone-binding globulin (SHBG), corticosteroid binding globulin (CBG) and fasting insulin) were cross-sectionally examined in 205 French working women. After adjustment for age, overall adiposity assessed by body mass index (BMI) was significantly associated with most metabolic parameters, whereas regional adiposity assessed by the waist-hip ratio (WHR) was significantly associated only with triglyceride, systolic and diastolic blood pressure. Blood pressure, glucose but not triglyceride, were also negatively and significantly correlated with SHBG and positively with fasting insulin. Negative independent associations were found between SHBG and both BMI and WHR, whereas CBG was positively associated only with WHR. Fasting insulin was no longer related to WHR after adjustment for BMI. After controlling for the effect of SHBG or insulin, the associations between triglyceride, blood pressure and both BMI and WHR were not substantially modified. After adjustment for BMI and WHR, fasting insulin was independently associated with both HDL cholesterol and diastolic blood pressure. In conclusion, in these French women, hormonal factors under study appeared to have little influence on the relationships between body fatness, body fat distribution, metabolic variables and blood pressure.

Regulation of plasma corticosteroid-binding globulin in adult cynomolgus monkey (Macaca fascicularis) during different reproductive states

The plasma concentration of the corticosteroid-binding globulin (mCBG) has been measured in Macaca fascicularis, during different stages of reproduction and under hormonal treatments. The mCBG level was determined by a specific electroimmunoassay. There was no difference between females in the follicular phase and intact males; mCBG concentrations were respectively (mean +/- SEM) 469 +/- 53 and 443 +/- 25.6 nmol/l. The mCBG levels levels were similar during both the luteal (469 +/- 33.5 nmol/l) and the follicular phase (469 +/- 53 nmol/l). Compared to intact males, the mCBG levels were higher (P less than 0.05) in castrated males (527 +/- 6.6 nmol/l). During gestation, no systematic variations were found and the mCBG levels were not statistically different from the values found during the follicular phase. When estradiol benzoate was administered to castrated animals, the mCBG concentrations increased rapidly. In contrast, the values were reduced slightly by testosterone treatment. The sex-steroid action on the mCBG levels was discussed and compared with the mSBP levels. We question also, the mechanisms involved in the regulation of the mCBG levels during pregnancy.

Immunochemical characterization of corticosteroid-binding globulin in human bronchoalveolar fluid

The corticosteroid-binding globulin (CBG) is a plasma protein which is present both in liver, where it is mainly synthesized, and in cells of different target tissues for glucocorticoids. Using monospecific antibodies raised against human CGB, we could demonstrate the antigenic identity of the protein in human bronchoalveolar fluid. We found that the bronchoalveolar fluid/serum concentration ratio of CBG was similar to that of albumin. Since albumin is not synthesized in pulmonary cells, it was concluded that, in healthy human, CBG enters bronchoalveolar fluid by diffusion through alveolar cells. It is suggested that the expression of the CBG gene in pulmonary cells could occur during the pathological state.

Combined effects of deafferentation and de-efferentation on isthmo-optic neurons during the period of their naturally occurring cell death

We have studied the effects on the chick embryo's isthmo-optic nucleus of de-efferentation alone or in combination with deafferentation. De-efferentation was achieved by pharmacological destruction of the axonal target cells in the retina at E13, or by colchicine-blockade of axoplasmic transport in the intraocular parts of the isthmo-optic axons at E13; deafferentation was by a tectal lesion at E11 or E12. De-efferentation alone causes all the isthmo-optic neurons to die, and mostly by the "endocytic-autophagic" mode of cell death, which is characterized by pronounced endocytosis (of an intravascularly injected label) and by intense, clumped activity of two lysosomal enzymes (acid phosphatase and N-acetyl-beta-glucosaminidase). Deafferentation plus de-efferentation caused there to be less endocytic-autophagic dying cells in the isthmo-optic nucleus than after de-efferentation alone, but all the neurons still died. Our interpretation is that deafferentation switched many of the isthmo-optic neurons to a completely different (nonendocytic, nonautophagic) mode of cell death.

Immunochemical characterization and quantification of the sex steroid-binding protein (SBP) in human amniotic fluid

The sex steroid-binding protein (SBP) is a plasma protein whose concentration in the maternal circulation increases during pregnancy. Using monospecific antibodies raised against human SBP, we could demonstrate the antigenic identity of the protein in human amniotic fluid. In this fluid, we found that the SBP concentration was correlated with the total protein concentration throughout gestation. The concentration gradient of SBP between maternal serum and amniotic fluid was compared to that of other serum proteins, in relation to their relative molecular mass, and it was concluded that SBP enters amniotic fluid in a non-specific manner similar to that of other serum proteins. It is suggested that SBP could act to sequester the sex steroid hormones in amniotic fluid.

Immunohistochemical detection of the sex steroid-binding plasma protein in human mammary carcinoma cells

A sex steroid-binding plasma protein-like antigen has been detected in human mammary carcinoma cells. A monospecific antiserum was used, and this protein was located mainly on the cytoplasmic membranes. These results are in agreement with a recent hypothesis according to which steroid hormones could be carried into cells by specific binding plasma proteins.

[Immunohistochemical study of the human testis and epididymis with a monospecific antiserum against the sex-steroid-binding plasma protein]

Sex-steroid-binding-plasma protein (SBP) is present at a very low concentration in human plasma. The preparation of a monospecific Rabbit antiserum against this protein allowed to demonstrate the tissular localization of antigenic determinants identical to SBP determinants by indirect immunofluorescence in human testis and epididymis.

Immunochemical characterization and quantitation of human sex steroid binding plasma protein

The interest in the measurement of human sex steroid binding plasma protein (h-SBP) is now increasing since it allows the estimation of the free fraction of circulating hormones in plasma. Up to this date, this protein could only be determined by measuring the total binding capacity of serum for dihydrotestosterone (DHT). The purpose of the present work was to purify the protein, to prepare a rabbit monospecific antiserum and to develop an immunoelectrophoretic assay of h-SBP. The immunological assay is specific, accurate and sensitive. A good correlation with the radioligand assay was found. The h-SBP levels obtained by immunoelectrophoretic assay of different serum samples were 5.3 +/- 1.4 (SEM) mg/L in normal men and 13.4 +/- 2.6 (SEM) mg/L in normal women.

Influence of sex hormone binding globulin and serum albumin on the conversion of androstenedione to testosterone by human erythrocytes

The influence of human serum albumin and sex hormone binding globulin (SHBG) on the enzymic conversion of androstenedione to testosterone in human erythrocytes was investigated in vitro. Total plasma and albumin delayed the conversion rate of androstenedione, while SHBG increased it markedly. The effect of SHBG was largely abolished by heating to 60 degrees C for 1 h and by saturating its binding sites by DHT. The effect of both proteins was found to be related to their concentration. It appears that the binding sites of albumin provide a mechanism for retarding androstenedione uptake by the erythrocytes and that the high binding affinity of SHBG for testosterone facilitates the diffusion of this steroid out of the cell and thus, displaces the chemical equilibrium within the cell.