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.      

The predictive value of the zona-free hamster egg penetration test in relation to in-vitro fertilization at various insemination concentrations

The aim of the study was to evaluate the predictive value of the zona- free hamster egg penetration test (ZHEPT) for success in in-vitro fertilization (IVF) at various insemination concentrations ranging between 0.1 and >0.6 x 10(6)/ml. The ZHEPT was assessed using sperm samples from 87 couples undergoing IVF treatment. A similar test was simultaneously performed on the same semen sample following ionophore induction of the acrosome reaction (ZHEPTii test). Both the tests were poorly correlated with the fertilization rate of IVF at all the insemination concentrations except at >0.6 x 10(6)/ml, when there was good correlation between the ZHEPTii test and the fertilization rate. Following exclusion of two cases with an oocyte problem, further statistical analysis revealed that both the ZHEPT and ZHEPTii tests were poorly correlated with fertilization rate in IVF in this treatment group. This study suggests that the ZHEPT (with and without ionophore induction of the acrosome reaction) has a poor predictive value for the success of fertilization in IVF treatment at any insemination concentration.      

The development of tibiofibular torsion

Summary We studied the angle of torsion of the leg in both lower limbs of 1607 schoolchildren of both sexes (1010 girls and 597 boys) aged between 3 and 17 years. Statistical differences were observed between one lower limb and the other in girls at the ages of 3, 8, 9, 10, 12, and 13 years but in boys no differences were observed. No statistical differences were found between the angle of torsion from one age to the next, except between the angles of 11 years and 12 years old boys. The torsional angle varies from approximatly 5° at 3 years to 17° at 17 years, with a slight, inconsistent increase in both sexes.

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Développement de l'angle de torsion de l'unité fibulaire

Résumé Nous avons étudié l'angle de torsion de la jambe des deux membres inférieurs de 1 607 enfants d'âge scolaire des deux sexes (1 010 filles et 597 garçons), âgés de 3 à 17 ans. Les différences statistiquement significatives ont été observées entre les deux membres inférieurs chez des filles âgées de 3, 8, 9, 10, 12 et 13 ans, alors que chez les garçons aucune différence n'a été observée. Aucune différence statistique n'a été retrouvée pour cet angle de torsion en fonction de l'âge, excepté entre les garçons de 11 et 12 ans. L'angle de torsion évolue approximativement de 5° à 3 ans, à 17° à 17 ans, avec une variation non significative entre les deux sexes.

     

Effects of selective media and atmosphere of incubation on the isolation of group A streptococci.

The effects of selective media and atmosphere of incubation on the isolation of group A beta-hemolytic streptococci were evaluated. Sheep blood agar medium with gentamicin (2.5 or 5.0 mug/ml) was inferior to antibiotic-free sheep blood agar medium. This resulted from the partial restriction of group A streptococcal growth on gentamicin medium. Recovery of beta-hemolytic streptococci from specimens in air, CO2, or anaerobic incubation was evaluated. The isolation of group A streptococci was equivalent in the three incubation atmospheres; however, non-group A beta- hemolytic streptococci were isolated significantly more often from specimens incubated in an anaerobic or CO2 atmosphere than from those incubated in air. Therefore, sheep blood agar medium, stabbed with a wire loop and incubated in air, is recommended for the isolation of group A streptococci from throat swabs.     

Reference ranges for bone densitometers adopted Australia‐wide: Geelong osteoporosis study

Bone densitometry reports a measure of fracture risk in comparison with young adults (T‐scores) and age‐matched peers (Z‐scores). To date, each manufacturer has provided its own reference range resulting in lack of uniformity. The Australia and New Zealand Bone and Mineral Society and Osteoporosis Australia have recognized the need to standardize the reference range and have recommended that data generated by the Geelong Osteoporosis Study (GOS) be used Australia‐wide. The GOS recruited a random, population‐based sample of adult women and measured bone mineral density (BMD) at the proximal femur and spine using a Lunar DPX‐L. These data were used to establish reference ranges for Lunar machines and, using conversion equations, for Norland and Hologic machines. The new standardized Australian reference ranges for BMD will enable consistent diagnosis of osteoporosis and categorization of fracture risk across different types of densitometers.