An epidemic of respiratory syncytial virus in elderly people: clinical and serological findings

In 1984-1985, an outbreak of respiratory syncytial virus (RSV) infection occurred in two geriatric wards. Among 68 patients (mean age +/- SD = 82.5 +/- 12.5 with respiratory signs, 52 had signs caused by RSV infection. Among all patients, the clinical and serological attack rates were 61.2% and 75.0%, respectively. The most frequent clinical presentation was intensive coughing (96.1%) and fever (96.1%) associated with expectorate (63.5%). The duration of the respiratory symptoms was 5 to 7 days. The disease gradually resolved, although in eight (15.4%) patients complications occurred. For periods of up to 1 year after infection, 172 sera were obtained and tested by complement fixation test (CFT), fluorescent assays for titrating specific IgG, IgA, and IgM, and Western blotting. Specific IgM appeared in six (11.5%) of the infected patients and peaked 2 to 6 months after infection, and there was no significant correlation with severity of clinical symptoms. However, higher peak G and A antibody responses were observed in persons with rales (CFT: P = 0.008; IgG: P = 0.042; IgA: P = 0.020), cough (IgG: P = 0.034), sputum (IgG: P = 0.030), dyspnea (CFT: P = 0.024), conjunctivitis (CFT: P = 0.025), and bronchitis (CFT: P = 0.018). The temporal patterns of IgA and CFT results were found to be similar, whereas IgG peaked later, i.e., between 2 and 6 months. The patients with the most severe symptoms had the highest antibody titers obtained by conventional tests and by Western blots. Thus, RSV can be an epidemic pathogen among elderly persons, although this illness is usually mild.

Characterization and Complexity of Wheat Developing Endosperm mRNAs

Free and membrane-bound (MB) polysomes and the corresponding polyadenylated RNAs (polyA(+) RNAs) have been isolated from developing wheat endosperm (Triticum aestivum L.) Free and MB poly(A)(+) RNAs, analyzed on isokinetic sucrose gradient with [(3)H]polyuridylic acid [poly(U)] hybridization detection, appear to be 11S to 12S in size with a 7% poly(A) tail for MB RNAs. cDNAs synthesized using both of these mRNA populations in presence of a potent RNase inhibitor (RNasin), have been used for hybridization kinetics experiments. The mean square fitting analysis of the hybridization kinetics between MB cDNA and its template reveals the presence of two abundance classes representing roughly (2/3) and (1/3) of the MB poly(A)(+) RNAs and containing the information for approximately 75 superabundant species (21,000 copies per cell) and 750 intermediate species (530 copies per cell), respectively. The mRNA population extracted from free polysomes is divided into three abundance classes. The first one is composed of superabundant sequences which would correspond to the MB superabundant mRNAs. The free mRNAs consist of about 11,000 diverse sequences, most of them being rare sequences. Heterologous hybridizations of MB cDNAs to free mRNAs have shown that some mRNAs are common to both populations. This could be explained either by a partial contamination or by free polysomes en route to their membrane destination. Contrary to the low number of diverse mRNAs corresponding to the legume seed storage proteins, the wheat endosperm superabundant mRNAs consist of about 75 different sequences which would encode most of the seed storage proteins, especially gliadins.

Changes in the polyadenylated messenger RNA population during differentiation of Vicia faba root cells

Using cDNA probes, the polysomal polyadenylated RNA populations of Vicia faba meristematic, elongating, and mature root cells were analysed and compared, with respect to complexity, abundance distribution, and sequence representation. These cells express 12 300, 15 800, and 15 200 sequences, respectively, of an average size of 1300 nucleotides, distributed in three frequency classes. Transition from the meristematic to the elongating stage is coordinated with the disappearance of 25-30% of the abundant RNA species (2000 copies per cell) and with the appearance of new transcripts corresponding to 3000-3500 genes expressed at an intermediate level (50-60 copies per cell) and belonging to the rare class (about 4 copies per cell). These new transcripts represent 12.5% of the mass of the mRNA during the elongating stage and are quantitatively modulated during the transition to the mature stage. Thus 80 to 85% of the polysomal polyadenylated RNA species expressed in elongating or mature cells are common to the three cell types.

Complexity of polysomal polyadenylated RNAs in Vicia faba meristematic root cells

As a first step in quantifying gene expression during differentiation of the Vicia faba root cells we have analysed the mRNA population from meristematic cells. Using cDNA X mRNA hybridizations we have shown that this population can be divided into three abundance classes (abundant, intermediate and rate) representing 37%, 34% and 29% of the mRNAs and containing 26, 610 and 11700 sequences respectively. The total base-sequence complexity of the mRNA population, as determined by cDNA X mRNA hybridization, was found to be 1.6 x 10(7) nucleotides. This estimate was confirmed by the determination of the amount of single-copy genomic DNA hybridizing to the mRNA. Expressed as the number of structural gene transcripts, this complexity corresponds to about 13000 mRNA sequences.