Based on evidence from morphological and histochemical studies and from clinical experience, the following hypotheses are proposed: carcinoma-in-situ (CIS) germ cells are malignant gonocytes; these CIS gonocytes have some capacity to regress into more primitive, totipotent embryonic cells which can give rise to all types of nonseminomatous germ cell tumours; the tumour germ cells of classical seminomas are malignant gonocytes derived from CIS gonocytes which have lost their ability to regress into totipotent embryonic cells; the ability of CIS gonocytes to regress into totipotent embryonic cells decreases with age, whereas the capacity to form classical seminoma cells is preserved; the transformation of CIS gonocytes into invasive tumours is dependent on factors such as gonadotrophins and/or testicular steroids; the pathogenesis of classical and spermatocytic seminoma are unrelated. As a consequence of these hypotheses an alternative nomenclature for carcinoma-in-situ, seminoma and dysgerminoma is suggested.

Leptin, the product of the ob gene, is thought to play a key role in the regulation of body fat mass. Beyond this function, it appears to be an integral component of various hypothalamo-pituitary-endocrine feedback loops. Because childhood and puberty are periods of major metabolic and endocrine changes, leptin levels and various hormonal parameters were investigated in a large cohort of healthy children and adolescents (312 males, 401 females, age 5.8-19.9 yr). For this purpose, a specific and sensitive RIA was developed that allowed the accurate measurement of low leptin levels in young lean children. With this assay, leptin proved to be a comparatively stable protein under common conditions of blood sampling and storage. Leptin levels increased in girls with age (r = 0.47, P < 0.0001), but decreased in boys (r = -0.34, P < 0.0001). An analysis according to pubertal stage showed a steady increase in girls between 2.51 micrograms/L (median) at Tanner stage 1 to 6.24 micrograms/L at Tanner stage 5. In boys, leptin levels were highest at Tanner stage 2 (2.19 micrograms/L) and declined thereafter to 0.71 microgram/L at Tanner stage 5. A strong exponential relationship was observed for leptin levels with body mass index (BMI) and percentage body fat as determined by bioelectric impedance measurements in a subgroup of subjects. This relationship was similar between boys and girls at Tanner stages 1 and 2. In boys, there was a significant decline of leptin at a given BMI with further progression of puberty that was much less pronounced in girls. Although the relative increase of leptin with BMI and percent body fat was the same in both genders, the absolute values at a given BMI or percent body fat were significantly lower in boys in late puberty and in adolescents. In boys, but not in girls, there was an inverse correlation with testosterone concentrations (r = -0.43, P < 0.0001), which explained 10.5% of the variation of leptin levels in a multiple regression model. Since BMI proved to be the major influencing variable, reference ranges were constructed using a best-fit regression line of the form leptin = a*e(b*BMI) and stratifying ranges according to gender and pubertal stage. In conclusion, these data suggest that 1) plasma leptin levels increase in girls and decrease in boys after Tanner stage 2 as the pubertal development proceeds; 2) they show a significant gender difference especially in late puberty and adolescence, even after adjustment for BMI or percent body fat; 3) the lower levels in males may be explained at least in part by a suppressive effect of androgens; 4) reference ranges with BMI as the independent variable should be stratified according to gender and pubertal stage.

Sertoli cells were studied using stereological methods in testes obtained from five children who were stillborn, and 31 individuals between 3 months and 40 years of age, who had suffered from sudden, unexpected death. The mean nuclear volume of the Sertoli cells, the numerical density of Sertoli cells, and the total number of Sertoli cells per individual were determined by point- and profile-counting of 0.5 micron sections. The nuclear volume of Sertoli cells increased from a median of 120 microns3 (range 53-130) during the period of 3 months to 10 years to 210 microns3 (170-260) in adults (greater than 25 years). The numerical density of Sertoli cells decreased from a median of 1200 X 10(6)/cm3 (870-1400) during childhood (3 months to 10 years) to 140 X 10(6)/cm3 (110-260) in adults (greater than 25 years). The total number of Sertoli cells per individual increased significantly from a median of 260 X 10(6) (130-520) during the late foetal period to 1500 X 10(6) (850-2900) in individuals from 3 months to 10 years of age. A further increase was found during puberty as the number of Sertoli cells in adults (greater than 25 years) was 3700 X 10(6) (2500-5600). These results indicate that significant qualitative and quantitative changes in the population of Sertoli cells take place after birth.

Background To describe cognitive function and to evaluate the association between potentially predictive factors and cognitive outcome in an unselected population of survivors of childhood brain tumors. Procedure We studied a consecutive sample of 133 patients (76 had received radiotherapy (RT)) who had a brain tumor diagnosed before the age of 15 years and were treated during the period January 1970 through February 1997 in the Eastern part of Denmark. Biologic effective dose of irradiation (BED) was assessed in 71 patients. One hundred twenty‐seven patients were able to cooperate to WISC‐R and WAIS‐R. Multiple regression models were constructed to evaluate relationships between possible risk factors and cognitive outcome. Results and Conclusions The mean intelligence (IQ) scores were substantially lower than the expected means of the general population. Younger age at diagnosis, tumor site in cerebral hemisphere, hydrocephalus treated with shunt, and treatment with RT were found to be significant predictors of lower cognitive functions. RT was the most important risk factor for impaired intellectual outcome. The mean observed full scale IQ was 97.1 (SD = 14.3) for the non‐irradiated patients and 78.8 (SD = 14.3) for the irradiated patients (adjusted P < 0.001). Verbal IQ, but not performance and full scale IQ, had a significant negative correlation to BED to the tumor site (P < 0.05). These results can be used to identify subgroups of children who are at increased risk for cognitive deficits allowing early and goal‐directed intervention. Med Pediatr Oncol 2003;40:26–34, © 2003 Wiley‐Liss, Inc.

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Germ cell cancer and disorders of spermatogenesis: An environmental connection? APMIS 106: 3-1 2, 1998.Why is there a small peak of germ cell tumours in the postnatal period and a major peak in young age, starting at puberty? And, paradoxically, small risk in old age, although spermatogenesis is a lifelong process? Why is this type of cancer more common in individuals with maldeveloped gonads, including undescended testis, gonadal dysgenesis and androgen insensitivity syndrome? Why has there, during the past 50 years, been a quite dramatic increase in testicular cancer in many developed countries? These are just a few of many questions concerning testicular cancer. However, the recent progress in research in the early stages of testicular cancer (carcinoma in situ testis (CIS)) allows us to begin to answer some of these questions. There is more and more evidence that the CIS cell is a gonocyte with stem cell potential, which explains why an adult man can develop a non-seminoma, which is a neoplastic caricature of embryonic growth. We consider the possibility that CIS cells may loose their stem cell potential with ageing. Along these lines, a seminoma is regarded a gonocytoma where the single gonocytes have little or no stem cell potential. The Sertoli and Leydig cells, which are activated postnatally and during and after puberty, may play a crucial role for both the development of the CIS gonocyte and progression of the neoplasm to invasiveness. The reported increase in testicular cancer is not the only sign that male reproductive health is at risk. There are reports that undescended testis and hypospadias have become more common. Also semen quality has deteriorated, at least in some countries. The epidemiological evidence suggests that environmental factors may play a role. Are the environmental hormone disrupters (e.g. DDT. PCB, nonylphenol, bisphenol A) to be blamed for the apparently synchronised deterioration in these aspects of male reproductive health?

Biochemical assessment of gonadal function during maturation in girls and in adult women can be troublesome. With the recent advent of specific assays for the gonadal peptides inhibin A and inhibin B, it might be possible to achieve a clearer picture of events. We therefore determined serum levels of inhibin A, inhibin B, FSH, LH and estradiol in a cross-sectional study of 403 healthy schoolgirls (aged 6 -20 yr) in relation to age and stage of puberty and in 181 healthy nonpregnant women (aged 20-32 yr) in relation to stage of the menstrual cycle. In addition, inhibin A and inhibin B were measured daily throughout the menstrual cycle in 10 healthy adult women. Levels of inhibin B are low or undetectable in prepubertal girls (median, 26.5 pg/mL; 95% prediction interval, <20-100 pg/mL), increase sharply through pubertal stage II to peak in stage III (median, 84 pg/mL; 95% prediction interval, 28-227 pg/mL) and thereafter decline through pubertal stages IV and V. These changes presumably reflect increasing ovarian stimulation through early puberty, resulting in an increased number of developing follicles, follicles reaching a later stage of development before undergoing atresia, or both. Declining levels in late puberty and adulthood probably reflect the onset of the menstrual cycle and the subsequent appearance of the luteal phase, where inhibin B levels are low. Inhibin A levels are undetectable or very low in early puberty (median, <7 pg/mL; 95% prediction interval, <7-14) pg/mL), increasing gradually through pubertal stages to reach their highest values in adult women (median, 21.5 pg/mL; 95% prediction interval, <7-129 pg/mL). Levels of inhibin A greater than 19 pg/mL are only seen in postmenarcheal girls in puberty and in adult women, again consistent with inhibin A being primarily produced by the corpus luteum. Determining cut-off levels of serum inhibin B regarding whether a girl had entered puberty resulted in similar (low) sensitivities and specificities as those found for cut-off levels of LH or estradiol due to the large overlap between serum values in Tanner stages I and II. Correlations between inhibin A and inhibin B and FSH, LH, and estradiol within pubertal stages are presented. In early puberty both inhibin A and inhibin B correlated positively with LH and FSH. In late puberty inhibin A correlated negatively with FSH and did not correlate with LH; inhibin B still correlated positively with both FSH and LH, now most strongly with FSH. In adult women during the menstrual cycle, serum inhibin B levels increased during the follicular phase, indicating the greatest production by follicles in early stages of development. In contrast, serum inhibin A levels peaked during the luteal phase, indicating the greatest production by the corpus luteum. In conclusion, serum inhibin A and inhibin B levels in normal puberty in girls show consistency with our knowledge of the manner in which these hormones are secreted within the menstrual cycle in adult women. The presented reference values may be of use in the clin...

Circulating IGF-I and -II are bound to specific insulin-like growth factor (IGF)-binding proteins (IGFBPs), of which IGFBP-3 binds the majority of the IGFs. IGFBP-3 levels are regulated by GH and have been suggested to provide additional information on GH secretory capacity compared to IGF-I. However, the diagnostic value of IGFBP-3 is still controversial, perhaps because the quality of the available normative data for IGFBP-3 varies. It has recently been shown that a large number of individuals is required to establish reference ranges for IGF-I that take into account age, sex, body mass index (BMI), and pubertal stage. Therefore, we measured IGFBP-3, IGF-I, IGF-II, IGFBP-1, and IGFBP-2 levels by RIA in 907 healthy children to establish well characterized normative data on IGFBP-3 according to age, sex, and pubertal stage and to study the complex relationship between IGFs and their BPs in puberty. We found that IGFBP-3 levels increase with age in children, with maximal levels in puberty; girls experience peak values approximately 1 yr earlier than boys. Age, sex, height, BMI, and pubertal maturation were all important factors in determining the circulating levels of IGFBP-3, whereas IGF-I levels were unaffected by BMI. Comparison of IGFBP-3 with IGF-1 concentrations revealed that they did not exhibit the same developmental pattern in puberty. IGF-I levels increased to relatively higher levels than IGFBP-3, leading to an increasing molar ratio between IGF-I and IGFBP-3 in puberty, when growth velocity is high. Concomitantly, IGF-II and IGFBP-2 levels were unchanged throughout puberty, whereas IGFBP-1 levels declined with age in prepubertal children, with lowest values in puberty. There was a highly significant correlation between IGF-I and -II and IGFBP-3 on a molar basis (r = 0.84; P < 0.0001). Thus, we speculate that IGFBP-3 is pivotal for circulating IGF bioactivity and that the increase in the molar ratio between IGF-I and IGFBP-3 reflects an increase in free, biologically active IGF-I. In conclusion, we have provided normative data on a large group of healthy individuals and conclude that age, sex, height, BMI, and pubertal maturation have to be taken into account before a single IGFBP-3 value in a growth-retarded child can be evaluated properly.