EFFECT OF NEURAMINIDASE ANTIBODY ON HONG KONG INFLUENZA

The relation between antineuraminidase antibody (A.N.) and natural influenza infection in 1968 was investigated in the community of Tecumseh, Michigan. The outbreak was caused by Hong Kong influenza virus, which contained a new haemagglutinin antigen (H3), while the neuraminidase antigen (N2) was more closely related to that of Asian viruses circulating since 1957. In the study group of two hundred and seventy-four randomly selected adults (aged 20-45), titres of N2 neuraminidase antibody were detected in a hundred and fifteen (42%) serum samples collected before the outbreak. Influenza infection during the course of the outbreak was identified serologically. The frequency of infection decreased significantly at increasing levels of pre-existing A.N. antibody. In those subjects who were not protected from infection, A.N. antibody significantly suppressed the clinical expression of infection. It is concluded that antibody against the neuraminidase of the influenza virus prevented or modified infection in a situation in which haemagglutinin antibody had no effect.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33917/1/0000183.pd

The Next Influenza Pandemic: Lessons from Hong Kong, 1997

The 1997 Hong Kong outbreak of an avian influenzalike virus, with 18 proven human cases, many severe or fatal, highlighted the challenges of novel influenza viruses. Lessons from this episode can improve international and national planning for influenza pandemics in seven areas: expanded international commitment to first responses to pandemic threats; surveillance for influenza in key densely populated areas with large live-animal markets; new, economical diagnostic tests not based on eggs; contingency procedures for diagnostic work with highly pathogenic viruses where biocontainment laboratories do not exist; ability of health facilities in developing nations to communicate electronically, nationally and internationally; licenses for new vaccine production methods; and improved equity in supply of pharmaceutical products, as well as availability of basic health services, during a global influenza crisis. The Hong Kong epidemic also underscores the need for national committees and country-specific pandemic plans.publishedVersio

The distribution of neuraminidase among the cytoplasmic membranes of HeLa cells infected with an influenza virus

1. The post-mitochondrial fraction of HeLa cells infected with influenza virus was sub-fractionated by density gradient flotation centrifugation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41681/1/705_2005_Article_BF01254167.pd

Isoelectric focusing studies of A2/1957 influenza neuraminidase and its subunits

Purified A2/1957 influenza neuraminidase (mucopolysaccharide N-acetylneuraminylhydrolase, EC 3.2.1.18) and its subunits were examined by isoelectric focusing (`electrofocusing') in sucrose gradients. Native neuraminidase contained enzymically active components with isoelectric points (pI) of about 5.2, 5.35, 5.5, 5.8, 6.2 and 6.5. The major components were at about pI 5.5 and 5.8. Neuraminidase was dissociated into subunits, whose sulfhydryl groups were blocked with iodo[14C]acetamide. 80% of isotope label incorporated was present in a single size of subunits with a molecular weight (Mr) of 51 000 as determined by sodium dodecyl sulfate acrylamide gel electrophoresis. The pI of denatured subunits was about 3.6 to 4.4. 14C-labelled peptides of tryptically digested neuraminidase had predominantly acidic isoelectric points. Results are consistent that the pI of native neuraminidase is about 1.5-2 pH units higher than the pI of its structural subunits, suggesting that side chain carboxyl groups are conformationally masked in the native enzyme, and that isoelectric heterogeneity of neuraminidase may result from conformation-dependent variations in the acid-base dissociation of these groups.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33847/1/0000105.pd

The preparation and properties of 14C-carboxamido-methylated subunits from A2/1957 influenza neuraminidase

A2/1957 influenza neuraminidase (mucopolysaccharide N-acetylneuraminylhydrolase, EC 3.2.1.18) was purified 15-fold from a recombinant virus, with about 25% overall yield of enzymic activity. Neuraminidase contained glucosamine, and a high proportion of serine and threonine. The partial specific volume was 0.713 cm3/g. Reduced neuraminidase was isotopically labeled in vitro by reaction with iodo[14C]-acetamide. When carboxamidomethylated in the absence of urea, enzymically inactive labeled material was obtained with a maximum size similar to native neuraminidase. When carboxamidomethylated in the presence of 6 M urea, labeled, dissociated subunits were obtained that did not associate or regain enzymic activity on removal of urea. The molecular weight of dissociated subunits was determined by sedimentation-diffusion methods as 50 000-54 000, and by sodium dodecyl sulfate-acrylamide gel electrophoresis as about 50 000. Thus native neuraminidase (mol. wt. about 200 000) is probably a tetramer. Neuraminidase contained about 21 cysteine residues per subunit. These appear to be present as disulfide bonds in the native enzyme.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34154/1/0000440.pd

Development of cold-adapted recombinant live, attenuated influenza A vaccines in the U.S.A. and U.S.S.R.

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24074/1/0000326.pd

Identification of sequence changes in the cold-adapted, live attenuated influenzavaccine strain, A/Ann Arbor/6/60 (H2N2)

Nucleotide sequences have been obtained for RNA segments encoding the 13132, P131, PA, NP, M1, M2, NS1, and NS2 proteins of the influenza A/Ann Arbor/6/60 (H2N2) wild-type (wt) virus and its cold-adapted (ca) derivative that has been used for preparing investigational live attenuated vaccines. Twenty-four nucleotide differences between the ca and wt viruses were detected, of which 11 were deduced to code for amino acid substitutions in the ca virus proteins. One amino acid substitution each was predicted for the PB2, M2, and NS1 proteins. Two amino acid substitutions were predicted for the NP and the PA proteins. Four substitutions were predicted for the PB1 protein. The biological significance of mutations in the PB2, PB1, PA, and M2 genes of the ca virus is suggested by currently available genetic data, a comparison with other available influenza gene sequences, and the nature of the predicted amino acid changes. In addition, the sequence data confirm the close evolutionary relationship between the genomes of influenza A (H2N2) and influenza A (H3N2) viruses.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27049/1/0000039.pd

Cold-adapted variants of influenza virus A : I. Comparison of the genetic properties of ts mutants and five cold-adapted variants of influenza virus A

The genetic properties of seven cold-adapted variants of influenza virus A were compared with those of nine 5-fluorouracil (5-FU)-induced ts mutants. The 5-FU mutants had previously been placed into seven complementation-recombination groups; five of the seven cold-adapted variants also had the ts phenotype, and all five were shown to share the group 1 lesion. Three of the cold variants also had additional ts lesions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23047/1/0000619.pd

Laboratory properties of cold-adapted influenza B live vaccine strains developed in the US and USSR, and their B/Ann Arbor/1/86 cold-adapted reassortant vaccine candidates

The adaptation of two influenza B strains (B/Leningrad/14/55 and B/Ann Arbor/1/66) to replication at 25[deg]C is described. Comparison of the two viruses indicates that both also exhibit temperature sensitive phenotypes, although that of the virus B/Leningrad/14/55 is less pronounced. When inoculated into ferrets both viruses replicate well in the trachea, but only the B/Leningrad/14/55 cold-adapted virus replicates in the lungs. This virus exhibited a moderate level of attenuation in the animals, in contrast to the B/Ann Arbor/1/66 cold-adapted virus, which was fully attenuated. Reassortant viruses deriving the surface antigens of the contemporary wild type virus B/Ann Arbor/1/86 and most or all of their other genes, from one or other cold-adapted parent, were virtually indistinguishable from their respective cold-adapted parents. The B/Leningrad/14/55 reassortant was slightly more attenuated than its cold-adapted parent in ferrets. These studies extend knowledge of the properties of viruses used to prepare experimental live influenza B human vaccines.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28728/1/0000554.pd

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care