Isotype-specific characterization of antibody responses to Onchocerca volvulus in putatively immune individuals

Isotypejsubclass-specific antibody responses to adult Onchocerca volvulus extract (OvAg) were assessed by both ELISA and immunoblotting for a group of putatively immune individuals (PIs, n = 29) from a hyperendemic area in Ecuador and for a group of infected individuals (INFs, n = 47) from the same region. As a group, the Pis have been previously shown to possess lower levels of OvAg specific IgG1, IgG2, IgG3 and IgG4 than INFs but semiquantitative analysis revealed that the relative proportions of these subclasses differs between the two groups. The IgG of the PI group contained a higher proportion of IgG3 and a lower proportion of IgG4 than the INF group. The frequency distribution of IgG3 responses was similar for the PI and INF groups. The frequency distributions for IgG1, IgG4 and IgE were significantly different between the PI and INF groups. A subgroup of the Pis were identified from frequency distributions and multivariate plots of individual isotype responses as having antibody responses (mainly IgG4) possibly indicative of cryptic infection. High IgE responses were exclusive to INF individuals, and a rare response type of high IgG3 with negligible levels of other isotypes/subclasses was seen only in the PI group. However, the majority of the Pis had negligible responses for all antibody classes. Immunoblots demonstrated no obvious differences in qualitative recognition between the PIs and INFs.     

Peptide synthesis on SepharoseTM beads

NHS-activated Pharmacia HiTrap Sepharose^TM was modified with 1,3-diaminopropane to give an amino-functionalized support suitable for solid-phase peptide synthesis. The amide linker p-[(R,S)-α-[1-(9H-fluoren-9-yl)-methoxyformamido]-2,4-dimethoxybenzyl]phenoxyacetic acid was incorporated and the acyl carrier protein sequence 65-74 was synthesized manually on this support by the Fmoc procedure under controlled conditions with monitoring of the coupling reactions. The performance of the support in automated multiple synthesis in open reactors, with an Abimed AMS 422 according to standard protocols, was evaluated by the synthesis of the acyl carrier protein sequence 65-74 and two other 15-mer and 18-mer peptides. The quality of the resulting crude peptides was determined by HPLC and MALDI-MS, and compared with the same sequences synthesized in parallel on the commercial peptide synthesis resin TentaGel S RAM. The modified HiTrap material was found to be particularly suited for Fmoc solid-phase peptide synthesis and should be advantageous for the utilization of immobilized peptides and peptide libraries in biological assays. © Munksgaard 1997.     

The Morphological Identity of Maternal Cells in Newborn Mice

The placenta has been considered ananatomical barrier which prevents maternal rejection of the fetal allograft. Thisview is no longer tenable since, in oneparticular inbred strain of mouse, maternal blood cells have been identified bymeans of radioisotope labels in newbornmice. Both maternal red cells and lymphocytes labeled, respectively, with radiochromium and tritiated thymidinehave been detected in newborn mice.This phenomenon appears independentof the trauma of normal delivery and,what is more, occurs before term.

Submitted on February 17, 1970 Revised on April 29, 1970 Accepted on May 18, 1970     

N.m.r. analyses of the histidine microenvironments in a human salivary proline-rich glycoprotein

The pK_a's of the three histidine residues in a proline-rich glycoprotein from human parotid saliva (PRG) were determined by 360 MHz proton n.m.r. spectroscopy. The addition of calcium (0.64 mm ) caused drops in the pK_a's of all three histidines by ～0.25 units. When imidazole and cyclo(l -histidine-l -proline) were used as model compounds, corresponding concentrations of calcium had no effect on their pK_a's. Also, the model compounds gave absolute pK_a values in good agreement with similar chemical species reported in the literature. Exchange lifetime data and previously reported hydrogen → deuterium exchange experiments suggest that the PRG histidine N^tH protons are not involved in hydrogen-bonds. Collectively, these data imply that changes in PRG conformation occur upon the addition of calcium.     

ANDREW SEXTON GRAY (1826–1907). A FOUNDER OF AUSTRALIAN OPHTHALMOLOGY: HIS LIFE AND TIMES

Andrew Sexton Gray was born in Limerick, Ireland, medically trained in Dublin, and was assistant to William Wilde, the distinguished oculist and aurist. He migrated to Victoria in 1859, was surgeon to a railway's construction company, then in 1862 began practice as a surgeon and oculist in Melbourne. In 1863 he founded a charitable eye and ear hospital, and had a very active, long life devoted mostly to ophthalmology. The hospital progressively expanded and became the centre for training for many ophthalmologists, as well as the nucleus for the cohesion of Victorian ophthalmology. History shows Andrew Sexton Gray to have been a founder of Australian ophthalmology.     

Removal time: a factor in the accuracy of irreversible hydrocolloid impressions

Controversy exists regarding the correct time of removal of an alginate impression from the mouth. To investigate the effect of time of removal on accuracy, a series of alginate impressions were made of the lower left quadrant of a subject having a cast gold crown with four reference marks on tooth no. 19. The impressions were removed from the mouth at 1-5, 2, 3, 4-5 and 7 min after the insertion of the tray. Accuracy of the impressions was assessed by comparing the distances between the reference marks in stone casts with standard measurements taken from the gold crown prior to cementation. Impressions removed at 1-5 and 7 min produced the greatest distortions buccolingually. For the mesio-distal lengths all time intervals produced casts which were larger than the standard. The reasons for these findings are discussed and possible explanations are presented.