Accuracy of self-reported body weight,height and waist circumference in a Dutch overweight working population

Background  

In population studies, body mass index (BMI) is generally calculated from self-reported body weight and height. The self-report of these anthropometrics is known to be biased, resulting in a misclassification of BMI status. The aim of our study is to evaluate the accuracy of self-reported weight, height and waist circumference among a Dutch overweight (Body Mass Index [BMI] ≥ 25 kg/m²) working population, and to determine to what extent the accuracy was moderated by sex, age, BMI, socio-economic status (SES) and health-related factors.     

A rapid method for the measurement of the oxoreductase activity of 11beta-hydroxysteroid dehydrogenase in granulosa-lutein cells from patients undergoing in-vitro fertilization

The presence of 11beta-hydroxysteroid dehydrogenase (11beta-HSD; EC1.1.1.146), the enzyme responsible for the interconversion of cortisol and cortisone, in granulosa-lutein (GL) cells is associated with a poor outcome in in-vitro fertilization (IVF). We have developed a simple method of assessing the reductase component of 11beta-HSD in these cells which is sufficiently rapid to provide data on the enzyme's activity prior to embryo replacement. Cells were pooled from follicular aspirates and challenged with cortisone within 2 h of aspiration. Cortisol secretion was then measured by radioimmunoassay. Conversion of cortisone to cortisol was linear for up to 3 h and was completely inhibited by glycyrrhetinic acid, a specific 11beta-HSD inhibitor. Initial velocity rates were determined for eight cortisone concentrations (range 0.1-8 micromol/l), and the apparent Km calculated (1.6 +/- 0.4 micromol/l). There was no evidence of substrate/product inhibition and conversion of cortisone to cortisol was <2% in all experiments. In subsequent work, cells were challenged with cortisone (6 micromol/l) for 2 h. Cells challenged for 2 h immediately following purification from follicular aspirates produced varying amounts of cortisol (range 25-150 nmol/pooled follicles from each patient, n = 10 patients), while basal outputs were <6 nmol/l. Enzyme activity was also examined in cells on a per follicle basis from individual patients and found to vary considerably (e.g. 19, 53 and 36 nmol/l cortisol/1000 cells, three follicles). Having established the method for assessing 11beta-reductase activity within GL cells, we performed a small prospective study on a series of 20 patients examining the enzyme activity within 110 individual follicles. 11Beta-reductase activity varied greatly from patient to patient and from follicle to follicle ranging from <0.024-0.57 nmol cortisol/microg DNA but at present low patient numbers preclude a meaningful correlation between enzyme activity and pregnancy rate. In summary, we have developed a simple, rapid (<8 h) assay for detecting the reductase activity of 11beta-HSD in GL cells isolated from pooled or individual follicles. This procedure is sufficiently quick to aid in the choice of embryo for replacement.      

Predicted maximal oxygen consumption of indigenous Siberians

This study presents physical fitness data on two indigenous Siberian populations, the Evenki and Keto. The Canadian Aerobic Test of Fitness (CATF) was utilized to provide estimates of maximal oxygen consumption (V?O₂ max) for a sample of 44 subjects (30 males, 14 females) as baseline data for further studies on changing fitness levels and the health problems associated with acculturation. Estimates of V?O₂ max average 46.2 ml kg^?1 min^?1 for males and 33.9 ml kg^?1 min^?1 for females. These values are comparable to those previously reported for other semisubsistence, cold adapted populations. The Siberian groups are below the Canadian norms in the 15–19 year age range, and thereafter track at about the 50th percentile throughout adulthood. This suggests that the cardiorespiratory systems of adult Evenki and Keto are functionally comparable to the average adult Canadian. © 1994 Wiley-Liss, Inc.     

Cryopreservation of oocytes and embryos: use of a mouse model to investigate effects upon zona hardness and formulate treatment strategies in an in-vitro fertilization programme

Mouse oocytes and embryos were obtained following ovulation induction of (C57B16 x CBA) F1 animals. Zonae pellucidae were exposed to alpha- chymotrypsin in phosphate-buffered medium (PB1) supplemented with 3 mg/ml bovine serum albumin upon a heated stage (37 degrees C) and were observed constantly through an inverted microscope. The endpoint of the bioassay was the limits of the zona no longer being seen clearly at x 200 magnification, and the time taken for each zona to dissolve was recorded. A dose-dependent response in dissolution time was clearly seen, with 1% alpha-chymotrypsin being chosen as the routine working solution. Cryopreservation of 2-cell mouse embryos using propanediol did not cause zona hardening but induced a small and significant softening, as gauged by the time taken for zona dissolution (2181 +/- 167 versus 1864 +/- 82 s). Zona hardening was not suspected to occur after the freezing of human embryos as there was no difference in implantation rates per embryo for in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatment cycles between fresh [IVF: 63/644 (9.7%); ICSI: 51/330 (15.5%)] and frozen embryos [IVF: 36/458 (7.9%); ICSI: 18/112 (16.1%)]. Conversely, significant hardening of the zonae of mature oocytes was seen following cryopreservation (747 +/- 393 s) compared with freshly ovulated oocytes (151 +/- 68 s). It is concluded that (i) the freezing of murine oocytes with propanediol results in zona hardening, implying a possible benefit of ICSI after the cryopreservation of human oocytes, and (ii) the cryopreservation of embryos is not associated with zona hardening or reduced implantation, making microdissection of the zona in such cases generally unwarranted.      

Gonadotrophin heterogeneity and biopotency: implications for assisted reproduction

The extensive heterogeneity of the gonadotrophin hormones, follicle stimulating hormone (FSH) and luteinizing hormone (LH), is due primarily to the heterogeneous nature of their carbohydrate side- chains, in particular sialic acid residues. In this review, we discuss the role of carbohydrate chains in receptor binding and activation, biological activity, and metabolic half-life. The synthesis and secretion of the various glycoforms of both FSH and LH appear to be under endocrine control with gonadotrophin-releasing hormone (GnRH), oestradiol and testosterone playing important roles. Evidence for different glycoforms having variable biopotency or different encoded functions is increasing, and the production and secretion of more or less acidic gonadotrophin species in different physiological states may represent an important mechanism whereby the pituitary regulates gonadal cell and organ function. This has potential importance for the development of new pharmaceutical reagents and new therapeutic regimens in assisted reproduction. It is envisaged that the use of existing and new forms of FSH/LH will allow patients to be treated in a more controlled and physiological manner, with treatment regimens individualized to the needs of the patient.      

Virus-induced cytokines regulate circulating lymphocyte levels during primary SIV infections

Decline in blood CD4+ lymphocytes during primary symptomatic infections with HIV is usually attributed to viral killing, and has not been considered in terms of altered lymphocyte migration and sequestration. We therefore sought to examine whether CD4+ cell loss from blood of macaques undergoing an acute primary SIV infection might be due to increased synthesis of cytokines, known to profoundly affect lymphocyte trafficking, rather than to direct lymphocyte destruction by virus. The findings indicate that rapid lymphocyte depletion following acute infection is not selective for CD4+ cells, correlates precisely with increased plasma IFN-gamma and tumor necrosis factor-alpha levels, and is reversible. CD4/CD8 ratios in lymph nodes with high viral burdens remain relatively unchanged despite lymphocyte loss from blood. Levels of cytokine mRNA measured in lymphoid organs reflect neither cytokine plasma levels nor their potential to induce sequestration. These results support a model of cytokine-induced lymphocyte extravasation to account for the acute HIV/SIV-induced CD4+ cell lymphopenia and raise questions regarding the extent to which altered lymphocyte migration plays a role in the gradual CD4+ cell depletion throughout infection.      

Trinucleotide expansion mutations in the cartilage oligomeric matrix protein (COMP) gene

Pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED) are two human autosomal dominant skeletal dysplasias characterized by variable short stature, joint laxity and early-onset degenerative joint disease. Both disorders can result from mut-ations in the gene for cartilage oligomeric matrix protein (COMP), an extracellular matrix glycoprotein. About one-third of PSACH cases result from heterozygosity for deletion of one codon within a very short triplet repeat, (GAC)5, which encodes five consecutive aspartic acid residues within the calmodulin-like region of the COMP protein. We have identified two expansion mut-ations in this repeat: an MED patient carrying a (GAC)6allele and a PSACH patient carrying a (GAC)7allele. These are among the shortest disease-causing triplet repeat expansion mutations described thus far, and are the first identified in a GAC repeat. A unique feature of this sequence is that expansion as well as shortening of the repeat can cause the same disease. In cartilage, both patients have rough endoplasmic reticulum inclusions in chondrocytes. The inclusions are also present in tendon tissue and can be reproduced in cultured tendon cells, suggesting that the pathophysiology of disease is similar in both cartilage and tendon.      

Normal and occluded mediastinal veins: MR imaging

The potential of magnetic resonance (MR) imaging to demonstrate the mediastinal veins was evaluated retrospectively in 25 patients with no evidence of a venous abnormality, 28 patients who had narrowing or occlusion of a mediastinal vein, and two patients who had a venous anomaly. In patients with venous occlusion, the MR images graphically demonstrated the sites and extent. MR images also demonstrated slow flow within venous structures proximal to the obstruction. Generally, venous collaterals in the mediastinum and chest wall were better seen with contrast material-enhanced computed tomography scans. The marked contrast on MR images between the signal void of normal vascular structures, the moderate signal intensity of tumor, and the high signal intensity of a thrombus or slowly flowing blood allows ready detection of venous occlusion and may suggest the nature of the occlusion.     

Pulmonary nodules: detection using magnetic resonance and computed tomography

Detection of pulmonary nodules using spin-echo magnetic resonance (MR) imaging was compared with detection using computed tomography (CT). Of the 25 patients studied independently by two radiologists, no lung nodules were detected in 11 (CT or MR), ten had a single nodule, and four had multiple nodules. The lesions not seen using CT or MR were less than 1.3 cm in diameter. The greater spatial resolution of CT enabled better detection of nodules close to the diaphragm, the pleura, or to each other, whereas the better contrast resolution of MR enabled the detection of several nodules close to blood vessels. With MR, nodules were best seen on images with long repetition times (2.0 sec). Most pulmonary nodules are seen using both CT and MR. CT generally enables the detection of more small nodules than MR does, and some low-density nodules near blood vessels are better displayed using MR.