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P Mead

Publications and source records attributed to P Mead.

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Immunologic and structural relatedness of the integrin beta 7 complex and the human intraepithelial lymphocyte antigen HML-1.

We recently cloned the newest human integrin beta subunit, termed beta 7, from a cDNA library constructed from SEA-activated T lymphocytes. In this communication, we report on the structure of the human integrin beta 7 protein complex determined using a rabbit anti-beta 7 peptide antibody raised to an N-terminal 22 amino acid residue sequence deduced from the human beta 7 subunit cDNA. The beta 7 subunit (Mr 116,000) expressed on PHA lymphoblasts associates with a single major alpha subunit (alpha H) that is distinct from the prominent T cell marker, integrin alpha 4. The alpha H subunit (Mr 180,000 nonreduced) displays a distinctive shift in size on reduction to an apparent Mr of 150,000. We show that these structural properties of the integrin beta 7 complex are shared with the cell surface antigen HML-1 found highly expressed on T cells which populate the intestinal epithelium and are proposed to be involved in mucosal immunity. Sequential immunoprecipitation and Western blotting demonstrate identity or close homology between the alpha H beta 7 and HML-1 proteins.

Amino Acid Sequence

A school-based measles outbreak: the effect of a selective revaccination policy and risk factors for vaccine failure.

Persons who received measles vaccine between 12 and 14 months of age have been found to be at increased risk of measles compared with those vaccinated at greater than or equal to 15 months of age. Because of this, in 1987 the Immunization Practices Advisory Committee of the US Public Health Service recommended that, during measles outbreaks, revaccination of persons vaccinated at 12-14 months of age be considered. During a school-based outbreak in New Mexico in 1987, the authors evaluated the effect of a mandatory revaccination policy in affected schools. Before the effect of revaccination, the overall attack rate in persons vaccinated at greater than or equal to 12 months of age was 4.1 cases/1,000 students; afterward, the risk was significantly reduced by 73%, to 1.1/1,000 students. The attack rate among students targeted for revaccination declined 100%, compared with 41% among those not revaccinated. Overall, attack rates were significantly lower in schools conducting revaccination early compared with schools holding later revaccination. In a retrospective cohort study of single-dose vaccines in one school, age at vaccination was not associated with risk of disease; however, persons vaccinated greater than or equal to 10 years before the outbreak were at increased risk, independently of age at vaccination. Revaccination of persons whose most recent vaccination was between 12 and 14 months of age appeared to control transmission in this outbreak. Further studies are needed to confirm these observations and to evaluate the effect of other revaccination efforts during outbreaks.

Adolescent

An obstetric approach to the prevention of early-onset group B beta-hemolytic streptococcal sepsis.

Group B beta-hemolytic streptococcus is one of the most common causes of neonatal sepsis. Despite its relationship to neonatal morbidity and mortality, no consensus exists for an approach to its prevention. Several characteristics of the organism such as high maternal carriage rates, the intermittent nature of this carriage, and the failure of antibiotics to permanently eliminate carriage have limited the success of proposed intervention protocols. In this clinical opinion we review characteristics of the organism and previously suggested intervention protocols. Then, based on this review and an analysis of recently published data, a protocol focusing on preterm births is presented. This proposal favors intrapartum treatment of all mothers who are delivered of preterm infants and who are either carriers of group B beta-hemolytic streptococci or whose carriage status is unknown. A comparison of the costs and benefits of this and other approaches is made.

Ampicillin