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A subline of U937 cells (U937D) was obtained in which creatine kinase B (CK-B) messenger RNA was present and bound to ribosomes, but CK activity was undetectable. Transformation of U937D cells with retrovirus vectors that contain the 3' untranslated region (3' UTR) of CK-B messenger RNA exhibited CK activity with no change in abundance of CK-B mRNA. The 3' UTR formed a complex in vitro with a component of S100 extracts from wild-type cells. This binding activity was not detectable in S100 extracts from cells that expressed CK activity after transformation with the 3' UTR-containing vector. These results suggest that translation of CK-B is repressed by binding of a soluble factor or factors to the 3' UTR.

Human pancreatic growth hormone releasing factor ) is the parent molecule of several peptides recently extracted from pancreatic tumours associated with acromegaly. A study was conducted to examine its effects on the release of growth hormone in normal volunteers and in patients with hypopituitarism and acromegaly.GRF (1-44) dose dependently stimulated the release of growth hormone in normal people and produced no appreciable side effect. This response was grossly impaired in patients with hypopituitarism and, although similar to the growth hormone response to hypoglycaemia, was of quicker onset and a more sensitive test of residual growth hormone function. Patients with acromegaly appeared to fall into (a) those with a normal response to GRF, whose growth hormone suppressed significantly with oral glucose, and (b) those who had an exaggerated response to GRF (1-44), whose growth hormone had not suppressed previously after oral glucose.Present methods for testing growth hormone deficiency entail using the insulin stress test, which is time consuming, unpleasant, and sometimes dangerous. A single intravenous injection of GRF now offers the possibility of an easier, safer, and more reliable routine test for growth hormone deficiency. It has the further

were employed in manufacturing and non-manufacturing work had almost identical rates ofabortion, and this relativity was not affected after logistic regression had accounted for differences in age, parity, history of abortion, education, and smoking. Thus there were no important differences between the two groups in these respects.This study thus provides support for the findings of Clarke and Mason that leatherwork in pregnancy may be associated with an increased risk of stillbirth.' The excess was entirely in the previous pregnancies, for which our data were complete and, we believe, reliable. In current pregnancies, in which stillbirths were incompletely ascertained, the absence ofexcess (one observed against 0-95 expected) is based on numbers too small to be interpreted. The difference between the ratio ofobserved to expected cases in current and previous pregnancies is no more than can be explained by chance. We did not, however, find any convincing evidence of an increase in fetal malformations. The only type of congenital defect on which Clarke and Mason commented were the three cases of trisomy 18 in an estimated 1200 births, or one in 400. As we had only 346 term pregnancies in leatherworkers and no case oftrisomy 18 we are not able to confirm or refute their finding.There is not necessarily any contradiction in finding a hazard that causes stillbirth and not malformation. A toxic agent acting later in pregnancy even over a short period could kill a fetus, whereas our knowledge of teratology suggests that only an agent acting at the right time in the first trimester might cause a malformation.The findings of Clarke and Mason and our own suggest that leatherwork may possibly expose women to a fetotoxic agent. We examined the work histories of the eight women in our study whose infants were stillborn; all operated sewing machines, three manufacturing shoes, three bags, and one belts. Five of the eight described exposure to glues (or cements, or both), one to paint, and one to silicone. It seems desirable to investigate the possible fetotoxicity ofmaterials used in the manufacture ofleather products. Four patients showed a significant reduction in tumour related hormone concentrations but in none did values return to normal. All five patients, however, noted definite symptomatic improvement and in one this was dramatic (disappearance of life threatening diarrhoea and correction of metabolic acidosis and hypokalaemia within 48 hours). Mild worsening ofsymptoms and increasing fasting tumour related hormone concentrations after three to six months of treatment were reversed by doubling the 12 hourly dose. The treatment was well tolerated and had no deleterious effect on fasting blood glucose concentrations.This somatostatin analogue seems a promising non-invasive treatment for metastatic pancreatic endocrine tumours.

Antisense RNA is a potentially powerful tool for creating dominant negative mutations, but one of the limitations of this strategy has been the relative inefficiency of antisense transcripts in blocking target gene expression. To identify more effective target sequences, helper-free retrovirusmediated gene transfer was used to introduce antisense RNAs complementary to multiple functional regions of the human creatine kinase B (CK-B) mRNA into U937 cells. Antisense RNA complementary to the last third of the coding and all of the noncoding region of this mRNA is highly effective; one or two antisense transcripts is sufficient to block the expression of one CK-B mRNA. In contrast, antisense RNA from which sequences complementary to the last 17 codons and all the 3' noncoding region have been deleted has no effect on CK-B expression. Neither antisense RNA alters the abundance of the target message, processing of the primary transcript, egress of the CK-B message from the nucleus, or the polysome profile of CK-B mRNA in sucrose gradients. These results point to a direct effect of the antisense transcript on translation and suggest that this effect may be explained at least in part by an inhibition of elongation or termination as a consequence of the duplex formed in the distal coding and/or 3' noncoding region.Antisense RNA has been used to block expression of target genes in prokaryotes and eukaryotes (1). General application of this strategy, however, has been limited by a lack of understanding of the basic rules for designing an efficient antisense system. Several systems suggest that the 5' noncoding region of the mRNA is a good target for antisense RNA (2, 3), while others report that coding sequences (4, 5), splice junction sites (6), and 3' processing sites (7) are also effective targets. Antisense RNA has been reported to block expression of the target gene by trapping of the duplex in the nucleus (8), accelerated turnover of the duplex leading to reduction in abundance of the target mRNA (3, 9-11), and altered processing of the target mRNA secondary to duplex formation (7, 12). Many reports (1, 3) indicate that the abundance of the antisense transcript must exceed that of the target mRNA by 100-fold or more to achieve even partial suppression. Efficient use of antisense RNA as a dominant negative mutation strategy would be enhanced if more effective mechanisms of antisense inhibition of gene expression were identified.The present study was undertaken to determine whether a more effective antisense strategy could be designed and, if so, to study the mechanism by which gene expression is blocked. Creatine kinase, an important enzyme in energy metabolism and an easily quantitated gene product, was selected as the target gene for these studies. Antisense RNA complementary to the area surrounding the stop codon was found to be a potent inhibitor of CK-B expression in U937 cells. Not only is antisense RNA complementary to this region of the CK-B mRNA potent; none of the previously described mechanisms of a...

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