Antigenic stimuli do not influence thymic B lymphocytes: a morphological and functional study in germ-free and conventionally reared piglets

We have recently reported that thymic B lymphocytes (TBL) are the first B-cell subpopulation undergoing isotype switching to IgG and IgA during embryonic life. The aim of this study is to analyze the influence of antigenic stimulation on TBL location and activity using a germ-free (GF) newborn pig model, in which maternal antibodies and antigens do not affect B-cell development. Immunohistological analysis showed that TBL were disseminated mainly in the thymic medulla. There were no differences in the distribution of TBL, both in GF newborn piglets before and after colonization with Escherichia coli and in older conventionally reared (CONV) piglets. The number of immunoglobulin (Ig)-secreting cells measured by the ELISPOT method was not influenced by microflora and food antigens. IgM-positive cells secreting IgM and CD45RC-positive cells spontaneously producing IgM, IgG, and IgA were detected in newborn thymus. Our findings suggest that TBL differentiation and Ig switching to IgG and IgA-secreting cells is not influenced by external antigens and that the thymic microenvironment plays an important role in this process.     

Inorganic Chemistry of Particulate Matter from the Nearshore Zone of Lake Michigan

Particulate matter from a nearshore region of southeastern Lake Michigan serves as a sink for trace metals and a conveyor of trace metals to the sediments. Fe, K, Mg, and Mn are always more concentrated in the hypolimnion than in the epilimnion, and Ca, Cr, Cu, Na, Sr, Zn, and total P are generally more concentrated in the hypolimnion than in the epilimnion. Enrichment of these metals in the hypolimnion particulates is attributed to sediment resuspension. Comparison of trace metal concentrations in the particulates with those in phytoplankton and zooplankton indicates that the plankton are not a significant contributor to the trace metal particulate chemistry of this nearshore region. Significant fractions (33% to nearly 100%) of total Cr, Cu, Fe, Mn, and Zn concentrations in the water column are associated with particulates.During the warmer months, calcium carbonate precipitates. Particulate chemistry changes little with the CaCO₃ formation, with the exception of an increased amount of calcium. Variations in the concentrations of trace metals are controlled either by both dolomite and hydrated manganese oxides or by an unknown phase believed to be organic in nature.     

Retrofit of 22 pipeline pumping stations with 3000-hp motors andvariable-frequency drives

Learning experiences encountered on a large variable-frequency induction motor drive installation are reported. The drives were widely dispersed at multiple locations and generally fed from very weak power systems. This paper discusses several different and unusual interferences and power quality issues encountered with different electrical utilities and makes suggestions with respect to specifications, logistics, installation and field measurements for the benefit of future projects     

Supercritical Antisolvent Particle Precipitation: In Situ Optical Investigations

The manner in which the presence of a solute can affect the mixing behavior of a solute, solvent and antisolvent in a supercritical antisolvent (SAS) micronization process is demonstrated. The mixing behavior was analyzed by applying a two‐dimensional (2D) Raman scattering technique. Mole fraction and partial density distributions were measured for the CO₂ antisolvent. The results originating from the optical investigations were correlated with the particle results. The experiments cover the variation of the solute concentration at fixed operating conditions of 10 MPa and 40 °C.     

Contents of volume 69 (1994/1995)

Contents of volume 69 (1994/1995)     

Light chain deposition disease as a cause of renal failure

The objective of the paper is to draw attention to a rare cause of rapidly progressing renal failure which developed in the course of four months as a result of light chain deposition disease. The authors submit two case-histories of the disease assessed by renal biopsy after previous clinical and laboratory suspicion of monoclonal gammapathy. In one patient in the sternal punctate plasmacytoma was diagnosed and in the second case it was not possible to detect any type of monoclonal gammapathy or another possible cause of disease. Renal failure was in both cases irreversible and both patients were enlisted in regular haemodialyzation treatment.     

An epithelial exclusion technique using the CO2 laser for the treatment of periodontal defects

When treating osseous defects associated with periodontitis, the healed result is a compromised regeneration of the attachment apparatus from epithelial downgrowth. This article demonstrates a laser ablation technique for excluding the epithelium from contacting the root surface of the periodontal wound. In accordance with the principles of guided tissue regeneration, the epithelium should be excluded for at least 30 days after surgical therapy. A series of case reports demonstrate the technique and the 6-month results that can be obtained using this approach. The regenerated tissue is confirmed through reentry procedures and radiographs.     

Persistance at a liberal arts college: A replicated, five-year longitudinal study.

Analyzed data on 1,171 freshmen entering Macalester College in 1964 and 1965 to observe factors related to persistance at the college. Voluntary withdrawals (Ss who left the college in good academic standing) did not differ from the persisters (graduates of Macalester) on precollege ability and achievement measures (including the Scholastic Aptitude Test, the Omnibus Personality Inventory, and the Allport-Vernon-Lindzey Study of Values). College GPAs for the withdrawal Ss, however, revealed that these Ss did not achieve as well as the persisters. The male failures (Ss having less than a C average at time of dropping from the College) had lower achievement in high school than the withdrawals, while the female failures did less well than the withdrawals on the precollege ability tests. No generalizable differences were apparent among the groups on personality and values inventories, home proximity to the college, or participation in an experimental advising program. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vocational interests of political scientists.

Collected SVIBs from 177 male members of the Midwest Conference of Political Scientists. Their interests were most like those of psychiatrists and psychologists, public administrators and social workers, librarians and musicians, and lawyers and author-journalists. When compared with sociologists, political scientists had interests less like those of applied biological scientists, physical scientists, outdoors and skilled worker occupations, administrators, and businessmen. Similar differences were found between psychologists and political scientists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)