T. MARSHALL and D. R. LINDSAY
T. McKeown, T. Marshall and R. G. Record
Department of Social Medicine, University of Birmingham, U.K.
Following Ylppö's suggestion that infants weighing less than 2500 g should be considered not mature (1920), birth weight was used as an index of maturity. This practice was open to criticism on two grounds : as an administrative device for identifying vulnerable infants, the limit of 2500 g was too high; and since low birth weight may result from either or both retarded fetal growth and early onset of labour, identification of maturity with weight confused two different classes of problems (McKeown & Gibson, 1951). Subsequently, by international agreement, the definition of prematurity was changed. But in the meantime another term had appeared in the literature; intrauterine growth retardation began to be referred to as an entity, in much the same way as was premature birth in the earlier period. The new term certainly distinguished low weight due to retarded fetal growth
D R Simorangkir, S Ramaswamy, G R Marshall, R Roslund and T M Plant
In primates, the time course of Sertoli cell proliferation and differentiation during puberty and its relationship with the expansion of undifferentiated type A spermatogonia that occurs at this critical stage of development are poorly defined. Mid and late juvenile and early and late pubertal male rhesus monkeys were studied. Testes were immersion fixed, embedded in paraffin, and sectioned at 5 μm. Sertoli cell number per testis, S-phase labeling (BrdU), and growth fraction (Ki67 labeling) were determined and correlated with corresponding parameters for undifferentiated type A spermatogonia (A dark and A pale). Dual fluorescence labeling was used in addition to histochemistry to monitor spermatogonial differentiation during the peripubertal period using GFRα-1 and cKIT as markers. While the adult complement of Sertoli cells/testis was attained in early pubertal monkeys after only a few weeks of exposure to the elevated gonadotropin secretion characteristic of this developmental stage, the number of undifferentiated type A spermatogonia several months later in mid pubertal monkeys was only 50% of that in adult testes. Both A dark and A pale spermatogonia exhibited high S-phase BrdU labeling at all stages of juvenile and pubertal development. Spermatogonial differentiation, as reflected histochemically and by relative changes in GFRα-1 and cKIT expression, was not observed until after the initiation of puberty. In the rhesus monkey and maybe in other higher primates including human, the pubertal proliferation of undifferentiated spermatogonia is insidious and proceeds in the wake of a surge in Sertoli cell proliferation following termination of the juvenile stage of development.
S. M. Laird, C. F. Dalton, M. A. Okon, R. A. D. Bunning, R. Marshall and T. C. Li
The presence of metalloproteinase activity in endometrial flushings obtained from premenopausal women, during the proliferative and secretory phases of the menstrual cycle, control post-menopausal women and women with post-menopausal bleeding (PMB) with or without adenocarcinoma was analysed by zymography. In addition, quantitative measurements of matrix metalloproteinase 2 (MMP-2), MMP-3, MMP-9 and tissue inhibitor of metalloproteinase 1 (TIMP-1) in the flushings were obtained by ELISA. The zymography results showed eight bands of activity, with molecular weights ranging from 51 to 208 kDa in the flushings from pre-menopausal women and post-menopausal women, particularly those with adenocarcinoma. Both zymography and ELISA showed that MMP-2 and MMP-9 were the major metalloproteinases found in the flushings and only low concentrations of MMP-3 were found. Concentrations of MMP-2 in pre-menopausal women were higher in flushings obtained during the secretory phase of the menstrual cycle than those obtained in the proliferative phase (P < 0.05), suggesting that it may play a role in embryo implantation. Concentrations of MMP-2 (P < 0.001), MMP-9 (P <0.05) and TIMP-1 (P < 0.001) in the flushings from post-menopausal control women were lower than those from pre-menopausal women. Concentrations of MMP-2 (P < 0.05) and TIMP-1 (P < 0.05) were higher in flushings from women with PMB without carcinoma compared with post-menopausal controls and concentrations of MMP-9 (P < 0.01) and TIMP-1 (P < 0.05) in flushings from women with adenocarcinoma were higher than in post-menopausal controls. Among subjects with PMB, concentrations of MMP-9 in women with adenocarcinoma were higher than those without carcinoma (P < 0.05). Our results show that concentrations of MMP-2, MMP-9 and TIMP-1, but not MMP-3, are associated with endometrial activity and, therefore, may have a role in the breakdown of endometrial tissue. In addition, the increased concentrations of MMP-9 in flushings of women with adenocarcinoma indicate that this particular proteinase is associated with the presence of endometrial neoplastic cells.