Stem-loop III in the 5' untranslated region is a cis-acting element in bovine coronavirus defective interfering RNA replication.

Higher-order structures in the 5' untranslated region (UTR) of plus-strand RNA viruses are known in many cases to function as cis-acting elements in RNA translation, replication, or transcription. Here we describe evidence supporting the structure and a cis-acting function in defective interfering (DI) RNA replication of stem-loop III, the third of four predicted higher-order structures mapping within the 210-nucleotide (nt) 5' UTR of the 32-kb bovine coronavirus (BCoV) genome. Stem-loop III maps at nt 97 through 116, has a calculated free energy of -9.1 kcal/mol in the positive strand and -3.0 kcal/mol in the negative strand, and has associated with it beginning at nt 100 an open reading frame (ORF) potentially encoding an 8-amino-acid peptide. Stem-loop III is presumed to function in the positive strand, but its strand of action has not been established. Stem-loop III (i) shows phylogenetic conservation among group 2 coronaviruses and appears to have a homolog in coronavirus groups 1 and 3, (ii) has in all coronaviruses for which sequence is known a closely associated short, AUG-initiated intra-5' UTR ORF, (iii) is supported by enzyme structure-probing evidence in BCoV RNA, (iv) must maintain stem integrity for DI RNA replication in BCoV DI RNA, and (v) shows a positive correlation between maintenance of the short ORF and maximal DI RNA accumulation in BCoV DI RNA. These results indicate that stem-loop III in the BCoV 5' UTR is a cis-acting element for DI RNA replication and that its associated intra-5' UTR ORF may function to enhance replication. It is postulated that these two elements function similarly in the virus genome.

Improved survival in lupus nephritis in the modern era (1979 - 1989).

We analysed outcome retrospectively in relation to treatment and disease stage in patients with systemic lupus erythematosus and glomerulonephritis, and compared these with similar patients referred to us during 1969 - 78, and other published series from the same period. Eighty two patients with lupus nephritis were referred during 1979 - 89. Of these, 73 were followed up for a mean of 58.1 (SD 34.5) months. The histological pattern in renal biopsies was WHO Class IV (diffuse proliferative glomerulonephritis) in 59% of patients. In the acute phase 43 patients received intravenous nethyl-prednisolone IG daily, for three days, in 25 accompanied by daily 4 litre plasma exchanges on 5 to 10 days. Twelve patients received induction therapy using oral cyclophosphamide during the acute phase, for 8 - 12 weeks only. Maintenance therapy was with oral prednisolone in all patients, accompanied by azathioprine in 84% of cases. Long- term cyclophosphamide was never used, neither intravenously nor orally. At 10 years actuarially calculated patient survival was 87% and survival of renal function 86% compared with 57% and 65% respectively in 1970 - 78 ([P < 0.01]). Survival was no different in patients with renal biopsies classified into the various WHO classes. In patients with Class IV biopsies, survival in those treated with prednisolone and azathioprine only was the same as that in those given intravenous methylprednisolone and/or plasma exchange as well. However, patients treated with methylprednisolone or plasma exchange tended to have more severe disease. At last followup, 24/82 patients were in complete remission, 23 had normal plasma creatinine concentrations but abnormal urine, ie proteinuria, haematuria, or both, 16 had abnormal urine and elevated plasma creatinine concentrations, and 9 had started renal replacement therapy. Eight patients had died. The survival of patients with lupus nephritis has improved in the past decade in patients with comparable severity of disease, and renal failure is no longer the principle cause of death. Results of maintenance treatment using azathioprine as adjunct to oral prednisolone in patients with severe nephritis are as good as those in series published elsewhere describing regular intravenous cyclophosphamide. No clear advantage was evident from the additional use of intravenous methylprednisolone and/or plasma exchange in the acute phase, in patients with WHO Class IV severe diffuse proliferative glomerulonephritis.