Embryonic mortality during the pre- and post-implantation periods of pregnancy in mature mice after superovulation.

Sexually mature mice were stimulated to superovulate by giving exogenous gonadotrophins at known stages of the oestrous cycle. Untreated animals which ovulated spontaneously served as controls. The number of oocytes ovulated by each female was estimated from counts of the number of CL of pregnancy, and the incidence of embryonic mortality during the pre- and post-implantation stages of pregnancy was assessed from the number of zygotes recovered from the reproductive tract at 2-0 and 4-0 days post coitum and of conceptuses examined at 7-5 and 11-5 days post coitum. The mean number of oocytes ovulated by treated animals was 39-54, compared with 12-80 in controls: in mice which had superovulated, 44% of the ova were lost before implantation compared with about 10% in the controls. Further losses occurred about the time of implantation and at mid-pregnancy and thus the number of embryos classified as normal rarely exceeded the maximum found in controls. Death at mid-pregnancy seemed to be preceded by developmental retardation. The possibility that genetic and environmental factors play a role in embryonic loss after superovulation is discussed.     

Changes in the morphology and synthetic activity of cultured rat tail tendon

Summary Isolated single fascicles from tail tendons of young rats were freed of epitenon cells and cultured in vitro for up to 7 days. The tissue remained viable, as judged by the structural integrity of cell organelles and the ability to synthesize DNA and glycosaminoglycans (GAG). The rate of DNA synthesis peaked after 2 days in culture and decreased slowly thereafter. Concomitantly, an increase in cell number was noted at the periphery of the fascicle. GAG production also increased during culture, sulphated GAG being increased proportionately more than hyaluronic acid. Dermatan sulphate was the predominant sulphated GAG in freshly isolated fascicles, but in cultured tissue, the newly synthesized sulphated GAG was more sensitive to degradation by chondroitinase AC and had an increased electrophoretic mobility. Fine structural changes were observed in cultured tissues such as the retraction of cell processes. rounding up of cell bodies and the appearance of gaps between collagen fibrils. Cultured tenocytes also frequently contained apparently phagocytized collagen fibrils which were not seen in freshly isolated fascicles, and this appearance was suggestive of collagen degradation occurring in vitro, although no change in the total hydroxyproline content was noted. The data show that when individual fascicles are cultured in vitro they undergo a process of matrix remodelling which has features in common with events occurring in vivo when tendons have been surgically manipulated.     

Mouse ferritin H sequences map to chromosomes 3, 6, and 19

Human and rodent genomes contain multiple copies of ferritin H and L subunit sequences, although it is not yet clear whether there is more than one expressed gene for either of these subunits. We have isolated a cDNA corresponding to mouse ferritin H subunit and observed that the mouse genome contains three to four H-related sequences. This cDNA was used to establish the genomic location of mouse ferritin H subunit genes by chromosomal in situ hybridization. Metaphase chromosomes of concanavalin A-stimulated lymphocytes from a WMP male mouse were examined by in situ hybridization with 3H-labeled cDNA and the chromosomes were identified by R banding (fluorochrome-photolysis-Giemsa method). The results indicate that mouse ferritin H-related sequences map at chromosomes 3, 6, and 19. Homology of synteny between human and mouse suggests that the sequence on mouse chromosome 19 corresponds to the structural H gene.     

Determination of glycogen and enzymes of glycogen metabolism in human hair follicles

The skin epithelium and its organelles use glycogen as well as glucose as source of energy. Therefore the characterisation of glycogen metabolism and the enzymes involved is important in the study of mechanisms regulating the normal or abnormal differentiation of skin organelles such as sebaceous glands and hair follicles.The present paper describes fluorimetric methods for the determination of glycogen and for the measurements of phosphorylase and phosphorylase kinase activity in one and the same lysate of minute tissue samples. The methods were tested for their suitability on freshly isolated human hair follicles and cultured hair follicle cells. The possible use of these techniques for studies on the pathophysiology of acne and hirsutism is discussed.     

Neutral endopeptidase 24.11 and angiotensin converting enzyme like activity in CALLA positive and CALLA negative lymphoid cells

Taking advantage of the recently demonstrated identity of common acute lymphoblastic leukemia antigen (CALLA) and neutral endopeptidase EC.24.11 (NEP) the presence of this ectoenzyme on lymphoid cells has been reassessed using highly sensitive assays (cleavage of [3H]-D-Ala2-leucine-enkephalin and binding of the inhibitor [3H]HACBO-Gly. NEP activity was found not only on already classified CALLA + ve cells but also on numerous cells (including mature B and polyclonal T cells) previously considered as CALLA-ve. This suggests that CALLA/NEP is expressed all along the differentiation pathway in B and T cell lineage. Moreover substantial ACE-like activity was also detected in three tested cells, all of the pre-B phenotype. The availability of specific inhibitors for these enzymes should help clarify their role in cell-differentiation.     

Quantitative determination of free cholesterol and cholesteryl esters in skin biopsies

A new technique is described for the determination of cholesterol in skin biopsies which is sensitive, practical and reproducible. The determination of cutaneous cholesterol is of clinical interest, because of its correlation with the degree of atherosclerosis. There was no correlation found between the blood total cholesterol and total triglycerides, and cholesterol and triglycerides determined in the skin biopsies. Determinations were carried out on several normal subjects, 7 long-distance runners, 34 hyperlipidemic patients. There was a significant increase with age of total skin cholesterol in the normal subjects, the values obtained with the long-distance runners had a tendency to be somewhat lower. All the patients investigated had higher cholesterol values than the normal controls or the sportsmen. This technique can be used therefore as a diagnostic tool to detect pathologies of skin lipids, or of tissue lipid metabolism, as for example in normolipidemic patients presenting corneal arcus or xanthelasmas.