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Immunoreactive somatomedin (IRSM) levels in term pregnancy material sera (MS) and newborn cord sera (CS) were higher and lower, respectively, than those in normal adults. IRSM levels in MS and CS were not correlated, suggesting that SM dose not cross the placenta. The similar levels of IRSM in arterial and venous CS suggest that the placenta does not produce SM. IRSM levels in CS were higher than those in newborn sera and were correlated with day 1 newborn sera, suggesting that the placenta may regulate fetal serum IRSM levels. Serum IRSM levels in normal children gradually increased from birth to peak levels at puberty. The mean levels of serum IRSM reached peak levels 2 yr earlier in females. Males near pubertal age with constitutionally delayed growth had lower serum IRSM levels than age-matched controls. Diagnostic measurements of serum IRSM in children requires comparison with age- and sex-matched controls. Serum SM levels may only approximately reflect the local concentrations or activities of SM in various tissues.

Cullin-RING ligases (CRL) are ubiquitin E3 enzymes that bind substrates through variable substrate receptor proteins and are activated by attachment of the ubiquitin-like protein NEDD8 to the cullin subunit. DCNs are NEDD8 E3 ligases that promote neddylation. Mammalian cells express five DCN-like (DCNL) proteins but little is known about their specific functions or interaction partners. We found that DCNLs form stable stoichiometric complexes with CAND1 and cullins that can only be neddylated in the presence of a substrate adaptor. These CAND–cullin–DCNL complexes might represent ‘reserve’ CRLs that can be rapidly activated when needed. We further found that all DCNLs interact with most cullin subtypes, but that they are probably responsible for the neddylation of different subpopulations of any given cullin. This is consistent with the fact that the subcellular localization of DCNLs in tissue culture cells differs and that they show unique tissue-specific expression patterns in mice. Thus, the specificity between DCNL-type NEDD8 E3 enzymes and their cullin substrates is only apparent in well-defined physiological contexts and related to their subcellular distribution and restricted expression.

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Our previous finding that about 15% of newly diagnosed patients with Type 1 (insulin-dependent) diabetes mellitus had human cytomegalovirus genome in their lymphocytes and islet cell autoantibodies in their sera, suggests that autoimmune Type 1 diabetes is associated with persistent cytomegalovirus infection under certain circumstances. This investigation was initiated to see if cytomegalovirus can induce islet cell autoantibodies and if the autoantibodies react with any specific islet protein(s). Monoclonal antibodies were generated after immunizing Balb/c mice with human cytomegalovirus. When these monoclonal antibodies were tested for the presence of islet cell antibodies were tested for the presence of islet cell antibodies, one (MCMVA-51) of 13 monoclonal antibodies reacted strongly with the islets. The titer of islet cell antibodies was 1:2000. When this monoclonal antibody was reacted with the proteins from the solubilized fraction of human pancreatic islets using the western immunoblotting technique, a band with a molecular weight of 38 kilodalton was detected. The 38 kilodalton band was not observed when the monoclonal antibody was reacted with the proteins prepared from pancreatic islet tissues of rats and mice or from other human organs including stomach, liver, spleen and brain, indicating that the 38 kilodalton protein is human islet cell-specific. It is concluded that human cytomegalovirus can induce islet cell antibodies that react with a 38 kilodalton human islet cell protein and that this protein component may represent islet cell-specific target antigens associated with persistent cytomegalovirus infection.

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Using a high specificity radioimmunoassay, antidiuretic hormone (ADH) concentrations were measured in the plasma of 33 expectant mothers during labour, in cord arterial and venous plasma of their infants at the time of delivery (19 delivered vaginally; 14 delivered by Cesarean section) and in the plasma of the same infants in the first few days of life. Extremely high concentrations of ADH (about 50 times higher than adult basal concentrations) were present in cord arterial blood indicating active fetal production of ADH. Plasma ADH decreased rapidly within an hour after birth and usually fell to adult basal levels during the first day of life. Stressed babies and babies subjected to difficult deliveries had higher plasma levels of ADH.