A comparison of the functional properties of two lepore hemoglobins with those of hemoglobin A1.

Lepore hemoglobins result from crossovers between normal beta and delta chain genes. Structural investigation of two newly discovered examples of Lepore hemoglobins revealed one of them to be structurally identical to hemoglobin Lepore Hollandia α₂^Aδ²² -x- β⁵⁰, a rarely occurring Lepore variant, while the second had the structure of hemoglobin Lepore Boston α₂^Aδ⁸⁷ -x- β¹¹⁶. Studies of the equilibrium and kinetic properties of the liganding reactions of these two Lepore hemoglobins, which differ only in three amino acid residues, and comparison of these with the known properties of hemoglobin A₁ (α₂β₂) and hemoglobin A₂ (α₂δ₂) have been carried out. A high value of n, the Hill coefficient, indicating normal heme-heme interaction, was observed in each hemoglobin along with a normal Bohr effect. However, a slight but definite increase in oxygen affinity was observed for each Lepore hemoglobin. Furthermore, kinetic studies indicated a slight but consistently increased rate of ligand combination and a somewhat decreased rate of oxygen dissociation for hemoglobins Lepore Hollandia and Lepore Boston at pH 7 and 20 °C. Apparently, the higher oxygen affinity of these Lepore hemoglobins over those of the normal hemoglobins A₁ and A₂ reflects changes of sequence that are common to both types of hemoglobin Lepore.     

Allencotyla pricei sp. n. (Microcotyloidea: Heteraxinidae) from the gills of the pile surfperch, Damalichthys vacca (Girard), in southern California

Allencotyla pricei sp. n. (Monogenea: Heteraxinidae) from the gills of pile surfperch, Damalichthys vacca (Girard), from Redondo Beach, California is described. This species is distinguished primarily by the prebifurcal position of the genital atrium and vagina, and by possessing an elongate esophagus. The systematic arrangement of microcotyloid forms characterized by an asymmetric haptor is discussed.     

An immune response profile model for immunogenicity quantitation

We propose an analytical model, which can simultaneously depict many fundamental characteristics of the immunogenicity of various vaccines. This model, the Immune Response (IR) profile, conveniently expresses the mathematical relation between pre- and post-vaccination titers. A vaccine's IR profile is antigen-specific, dose-dependent and post-vaccination interval-dependent. The maximal capability for serological response to a vaccine can be determined using this model irrespective of the dose administered, the post-vaccination assay interval, or the live or killed state of the vaccine. The IR profile obtained from analysis of booster vaccine responses in a limited number of seropositive study subjects can be used to predict maximal antibody titers which are expected after vaccination and can predict the geometric mean post-vaccination antibody titer of a cohort of subjects undergoing primary immunization. Using this model, it is anticipated that the immunoregulation implied by the IR profile may also prove to be correlated with cellular subpopulations and idiotypic antibody functions. Although derived from influenza vaccines analyses, the model successfully describes immune response characteristics following natural infection with malaria and following diphtheria and rubella vaccine administration.     

The Flora of the Perivaginal Area: The Normal Flora and the Effect of a Deodorant Spray

S ummary . The microbial flora of the thigh adjacent to the vaginal labia and of the mucosal surface of the labia has been examined quantitatively and qualitatively in students from Colleges of Education and a University, and in persons attending a Consultant Gynaecologist for non-suppurative conditions. In the 2 student populations, members of the Micrococcaceae and diphtheroids were the most common organisms but all populations yielded many organisms of gut origin. Differences between the populations may relate to social and hygienic conditions and should make us wary of direct comparisons with other, different populations. The effect of intimate hygiene deodorants containing 0.01% or 0.02% of chlorhexidine was compared with a base spray containing no antibacterial agent. No significant effect of these sprays on the microbial flora could be demonstrated.     

The Drosophila Platelet-derived Growth Factor and Vascular Endothelial Growth Factor-Receptor Related (Pvr) Protein Ligands Pvf2 and Pvf3 Control Hemocyte Viability and Invasive Migration

Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) family members are essential and evolutionary conserved determinants of blood cell development and dispersal. In addition, VEGFs are integral to vascular growth and permeability with detrimental contributions to ischemic diseases and metastatic cancers. The PDGF/VEGF-receptor related (Pvr) protein is implicated in the migration and trophic maintenance of macrophage-like hemocytes in Drosophila melanogaster embryos. pvr mutants have a depleted hemocyte population and a breakdown in hemocyte distribution. Previous studies suggested redundant functions for the Pvr ligands, Pvf2 and Pvf3 in the regulation of hemocyte migration, proliferation, and size. However, the precise roles that Pvf2 and Pvf3 play in hematopoiesis remain unclear due to the lack of available mutants. To determine Pvf2 and Pvf3 functions in vivo, we generated a genomic deletion that simultaneously disrupts Pvf2 and Pvf3. From our studies, we identified contributions of Pvf2 and Pvf3 to the Pvr trophic maintenance of hemocytes. Furthermore, we uncovered a novel role for Pvfs in invasive migrations. We showed that Pvf2 and Pvf3 are not required for the directed migration of hemocytes, but act locally in epithelial cells to coordinate trans-epithelial migration of hemocytes. Our findings redefine Pvf roles in hemocyte migration and highlight novel Pvf roles in hemocyte invasive migration. These new parallels between the Pvr and PDGF/VEGF pathways extend the utility of the Drosophila embryonic system to dissect physiological and pathological roles of PDGF/VEGF-like growth factors.