Laminin-5 promotes neurite outgrowth from central and peripheral chick embryonic neurons.

Laminin-5 (Ln-5) is an essential component of epithelial basal laminae that is also expressed in the developing nervous system. Here we use a convenient, simple and reproducible in vitro fluorescent assay to assess the neurite outgrowth promoting activity of purified Ln-5. Embryonic chick neurons from dorsal root ganglia, ciliary ganglia, and (to a lesser extent) retina extended neurites on Ln-5, but the neurite outgrowth promoting activity was not as great as that of Ln-1 or Ln-2. Neurons from diencephalon, telencephalon, and spinal cord did not respond to Ln-5.

Safety and immunogenicity of adjuvanted and unadjuvanted subunit influenza vaccines administered intranasally to healthy adults.

Antigen-specific mucosal immunity is thought to be important for protection against influenza virus infection. Currently licensed parenteral influenza vaccines stimulate the production of serum antibodies, but are poor inducers of mucosal immunity. The adjuvant MF59 has been shown to enhance the humoral immune response to parenteral influenza vaccine in humans and the mucosal immune response to intranasally-administered influenza vaccine in mice. We conducted an open-label safety study followed by an observer-blind, randomized trial comparing the immune response to intranasally-administered subunit influenza vaccine adjuvanted with MF59, unadjuvanted subunit influenza vaccine, and placebo. Adverse reactions did not occur significantly more frequently in vaccinees than placebo recipients. Of 31 subjects receiving 2 doses of MF59-adjuvanted influenza vaccine, 19 (61%), 8 (26%), and 11 (35%) developed a mucosal IgA response to influenza A/H1N1, A/H3N2, and B, respectively. The percentage of subjects with a serum antibody response was slightly lower. The immune responses to adjuvanted vaccine were not significantly different from those to unadjuvanted vaccine. Both vaccines gave more frequent responses than seen in placebo recipients, indicating the potential of intranasal inactivated vaccines to stimulate local IgA responses.

sck1, a high copy number suppressor of defects in the cAMP-dependent protein kinase pathway in fission yeast, encodes a protein homologous to the Saccharomyces cerevisiae SCH9 kinase.

Schizosaccharomyces pombe regulates intracellular cAMP levels, and thus cAMP-dependent protein kinase (PKA) activity, in response to changes in nutrient conditions. Mutations in any of eight git genes inhibit glucose repression of fbp1 transcription, alter the cell morphology, and cause a reduction in the growth rate. The eight git genes encode components of an adenylate cyclase activation pathway, adenylate cyclase itself, and the catalytic subunit of PKA. Three of these genes have been identified in other studies as regulators of meiosis. Here we show that the sck1 gene, cloned as a high copy number suppressor of a mutation in git3, is able to suppress the defects conferred by a mutation in any of these git genes. Sequence analysis suggests that sck1 encodes a protein most closely related to the Saccharomyces cerevisiae SCH9 protein kinase that had previously been identified as a high copy number suppressor of mutations in S. cerevisiae that reduce or eliminate PKA activity. Disruption of the sck1 gene causes a significant delay in exit from stationary phase when combined with a disruption of the pka1 (git6) gene encoding the catalytic subunit of PKA. However, the sck1 disruption by itself has little or no effect upon fbp1 transcription, meiosis, or exit from stationary phase, and does not enhance the constitutive fbp1 transcription observed in a pka1 mutant. Therefore, sck1 appears to function in a redundant fashion to pka1, but to varying degrees, in the pathways regulated by pka1.

Regulation of integrin affinity states through an NPXY motif in the beta subunit cytoplasmic domain.

The ligand binding affinities of the integrins are regulated through their cytoplasmic domains. To identify specific residues that are involved in this process, we have generated mutants in the beta 1 and beta 3 tails and coexpressed them in Chinese hamster ovary cells with constitutively active alpha subunits. These alpha subunits are chimera of extra-cellular and transmembrane alpha IIb joined to the cytoplasmic domains of alpha 5, alpha 6A, or alpha 6B and confer an energy-dependent high affinity state when expressed in Chinese hamster ovary cells. The affinity state of these transfectants was determined by analyzing the binding of PAC1, an antibody that specifically recognizes the activated form of the reporter group, extracellular alpha IIb beta 3. We have identified point mutants in several areas of the beta tails, which result in a reduced ability to bind ligand. Complete abolition of PAC1 binding was obtained with mutants in an NPXY motif found in many integrin beta subunits and implicated in the internalization of other cell surface receptors. Similar effects on PAC1 binding were observed whether coexpression was with alpha chimera containing alpha 5, alpha 6A, or alpha 6B cytoplasmic sequences. These studies identify a novel role for the NPXY motif in the regulation of integrin binding affinity.

Diagnostic tests for poliovirus infection: a comparison of neutralization and immunofluorescence for the identification and typing of stool isolates.

Neutralization and indirect immunofluorescence were compared for the identification and serotyping of poliovirus. Indirect immunofluorescence was highly concordant with neutralization and offers a more rapid procedure for identification and characterization of poliovirus strains.

Seroresponse to trivalent oral poliovirus vaccine as a function of dosage interval.

Seroresponses to trivalent oral poliovirus vaccine are not uniform throughout the world. Definition of the variables that determine successful immunization is vital to ensure global polio eradication. One such variable may be dosage interval. To investigate this effect 108 infants were enrolled in a clinical trial and randomly assigned to receive three doses of trivalent oral poliovirus vaccine (standard United States formulation) at 2, 3 and 4 or 2, 4 and 6 months of age. After three doses of vaccine given before 6 months of age, immunity was virtually complete for each of the three poliovirus types in both groups. After two doses the seroresponse rate to each type was less with the shorter dose interval. However the difference was not significant (P = 0.15) in the sample size studied. Such responses differ markedly from those seen in developing countries, where four or more doses of vaccine may fail to provide complete protection. Differences other than dosage interval must contribute to those failures.

Increased survival rate in very low birth weight infants (1500 grams or less): no association with increased incidence of handicaps.

The incidence of major handicaps was studied in a selected high-risk population of 1919 very low birth weight (less than or equal to 1500 gm) infants born between 1976 and 1985. Seventy-four percent of these infants were discharged alive. We have handicap information on 632 infants who have been followed for up to 7 years of age; 462 were evaluated at 18 months or later. Patients lost to follow-up represent 55% of the eligible population, but inpatient morbidity factors were available for the entire population and were used to calculate synthetic estimates of handicap rates. The overall incidence of severe major handicaps at 18 months was 18.0% (83/462). Cerebral palsy was found in 7.6%, and 6.5% were mentally retarded (IQ less than or equal to 70). Severe retinopathy of prematurity was present in 5.5%, and 5.4% of the infants had neurosensory hearing loss. Thirty-one infants (6.7%) had more than one handicap, the most common combination being cerebral palsy and mental retardation. Outcome of infants grouped by 250 gm birth weight intervals was compared for two periods (1976 to 1980, and 1981 to 1985); the numbers of survivors in each birth weight group increased during the second period, especially in the 500 to 750 gm and the 751 to 1000 gm groups. The observed incidence of major handicaps decreased from the first 5-year period to the second 5-year period (p less than 0.001). The largest decreases in the observed proportion handicapped occurred in the two lowest birth weight groups. The incidence of multiple handicaps also dropped; again, the two lowest birth weight groups showed the largest decrease. We conclude that an increased survival rate of very low birth weight infants need not be associated with an increased incidence of major handicaps.

Parental perceptions of vulnerability of formerly premature infants.

This study explores a possible precursor of the vulnerable child syndrome, a constellation of behaviors thought to develop as a result of excessive parental anxiety. Healthy 3-year-old children who had been born prematurely were compared to children born at term, using a single instrument. Mothers of premature infants reported a significantly greater sense of vulnerability about their children than did mothers of term infants. Antecedents and correlates of vulnerability are explored. Mothers with more education reported a greater sense of vulnerability than did less well-educated mothers, while mothers who reported greater well-being and marital satisfaction reported a lower sense of vulnerability. A greater sense of vulnerability was associated with more behavior problems and more somatic and internalizing symptoms. The data have important implications for nurses caring for infants in neonatal intensive care units, as well as in pediatric ambulatory and hospital settings.

Is my child normal yet? Correlates of vulnerability.

There are some children whose parents believe them to be unusually susceptible to medical or developmental problems--"vulnerable"--despite a lack of objective evidence of any difficulty. The "vulnerable child syndrome" refers to a constellation of behaviors that are thought to develop as a result of this excessive parental anxiety and subsequent difficulties in limit setting. In this study, the sense of vulnerability expressed by mothers concerning their healthy 3-year-old children is explored; children born prematurely and with considerable neonatal morbidity are compared with children born at full-term. Sense of vulnerability is assessed through the use of a simple instrument, the use and validity of which are described. Mothers of premature infants described a significantly greater sense of vulnerability concerning their children than did mothers of full-term infants. Mothers with more education described a greater sense of vulnerability than did less well-educated mothers, although mothers who claimed greater well-being and marital satisfaction described a lesser sense of vulnerability. Mothers with a greater sense of vulnerability concerning their children also reported more behavior problems, especially in the sphere of discipline, peer relationships and self-control, and in internalizing and somatic symptoms. Pediatricians can intervene in the development of the vulnerable child syndrome by recognizing those children at special risk and helping their parents to nurture their health and independence.