Interleukin 1 responsiveness and receptor expression by murine TH1 and TH2 clones

Murine Th1 and Th2 T cell lines differ in their responses to interleukin 1 (IL 1). Therefore, we examined two T-cell lines, D10.G4.1 (Th2) and MTg12B (Th1) in an attempt to correlate IL 1 receptor (IL 1R) expression with their IL 1 responsiveness. D10.G4.1 cells, which respond to IL 1, expressed two forms of the IL 1R, with molecular masses of approximately 80 kDa and approximately 60 kDa. In contrast, MTg12B cells failed to respond to IL 1 and only expressed the approximately 60 kDa receptor form. This suggests that the approximately 80 kDa receptor is essential for signaling. Expression of both IL 1R forms on D10.G4.1 cells could be inhibited by the anti-IL 4 antibody, 11B11. Antigen presentation reversibly upregulated both forms of the IL 1R, whereas stimulation with concanavalin A (ConA) and anti-CD3 only upregulated the approximately 60 kDa moiety. Upregulation of the approximately 80-kDa IL 1R by repeated antigenic stimulation resulted in a marked increase in sensitivity of D10.G4.1 cells to IL 1.     

Schistosoma mansoni: glycosyl transferase activity and the carbohydrate composition of the tegument.

Homogenates of adult Schistosoma mansoni contain enzymes which transferred [¹⁴C]mannose, [¹⁴C]glucose, and [¹⁴C]galactose from GDP-[U-¹⁴C]mannose, UDP-[U-¹⁴C]glucose, and UDP-[U-¹⁴C]galactose respectively to a lipid acceptor; in comparison, free [¹⁴C]mannose, GDP-[U-¹⁴C]fucose, and UDP-[U-¹⁴C]acetyl-glucosamine were poorly transferred. The lipid acceptor is believed to be an intermediate in the glycosylation of the worm's glycoproteins and in the biosynthesis of oligosaccharides and glycolipids. The tegument of adult worms was isolated by the freeze-thaw procedure and sugars associated with macromolecules in this fraction were analyzed; the major monosaccharide components were glucose, galactose, and mannose. These results suggest that the mechanism of glycosylation of the adult schistosome's tegumental macromolecules may occur through the glycosyl transferase system. The schistosome mannosyl transferase (EC 2.4.1), which is membrane bound was solubilized with 0.1% Triton X-100 without loss of activity; after density gradient centrifugation there was a peak of enzymic activity in a region of density 1.08, which could not be associated with any particular organelle.     

A simple radioassay for dihydroorotate dehydrogenase

A simple radioassay for dihydroorotate dehydrogenase (DHO-DHase; EC 1.3.3.1) has been developed. l-[carboxy-¹⁴C]Dihydroorotate was prepared from [carboxy-¹⁴C]orotic acid using DHO-DHase derived from Zymobacterium oroticum and was purified by elution from DEAE-Sephadex A-25 with 0.2 m ammonium formate, pH 7. DHO-DHase activity in human spleen mitochondria was determined by the release of ¹⁴CO₂ from the carboxy-¹⁴C-labeled l-dihydroorotate, the reaction being coupled with added orotate phosphoribosyltransferase and orotidylate decarboxylase. An apparent K_m value of ～5 μm for l-dihydroorotate was established using the radioassay. This value correlated well with results from other methods.     

Schistosoma mansoni: a comparative study of artificially transformed schistosomula and schistosomula recovered after cercarial penetration of isolated skin.

A comparison was made of the ultrastructure, development and antigenic nature of the surfaces and of the viability of three types of Schistosoma mansoni: schistosomula formed after cercariae had penetrated isolated skin (SS) schistosomula produced after mechanical separation of cercarial tails from bodies (MS), and schistosomula transformed from cercariae after incubation in fresh rat serum (RS). Within 2h of transformation, the surface membranes of all three types of schistosomula had changed from trilaminate to heptalaminate structures and SS and MS had lost their cercarial glycocalyx. Initially a dense amorphous material was demonstrated on the surfaces of RS, which was thought to be the result of an interaction between a factor in rat serum and the glycocalyx; this material was greatly reduced within 2 h of transformation. The pre-acetabular glands of SS were emptied while those of MS and RS retained their contents. Immunofluorescent studies showed that all schistosomula bound serum from mice immune to S. mansoni, but the binding was stronger with MS and RS. The mixed agglutination reaction demonstrated the presence of human A and B blood group-like antigenic determinants on approximately 30% of 3h old SS; these determinants were not detected on MS or RS. In vitro, the development of MS and RS was similar to SS; the first schistosomula reached the "gut-closed" stage by day 10; 50-70% of SS reached this stage by day 12, in contrast to only 25-50% of MS and RS. Between 28 and 45% of all schistosomula developed to maturity when injected intravenously into mice. It was concluded that the two types of artificially prepared schistosomula fulfil the main criteria of transformation from cercaria to schistosomulum. Further, it is suggested that MS are the most appropriate source of material for immunochemical and physiological studies.     

Cell-free synthesis of Schistosoma mansoni surface antigens: stage specificity of their expression

Messenger RNA has been extracted from all stages of the life cycle of the parasitic multicellular helminth Schistosoma mansoni. In vitro translation of these mRNA preparations in rabbit reticulocyte lysates yielded in each case a large number of polypeptides. Immunoprecipitation of translation products either by serum from immune mice or from human patients demonstrated that relatively few, approximately 10, polypeptides are recognised as antigens. Two of the in vitro synthesised antigens, of mol. wts. 22 000 and 14 000, were demonstrated to correspond to schistosomula surface antigens. The expression of these antigens may show stage specificity. Both are readily detected from adult and sporocyst translation products, neither from schistosomula and only the 22 000 antigen from miracidia. This is an unexpected finding since similar polypeptide antigens occur on the surface of schistosomula. These results indicate that not only are schistosomula surface antigens preformed at the preceding sporocyst stage, i.e., within the snail host, but they also remain invariant throughout the life cycle in the vertebrate host. Two other prominent schistosomula surface antigens of mol. wts. 38 000 and 32 000, were not recognised amongst cell-free translation products directed by RNA from any life cycle stage. The demonstration that at least two schistosomula surface antigens are detectable amongst adult mRNA cell-free translation products demonstrates the feasibility of identifying the genes encoding them in cDNA libraries from adult worm mRNA.     

A Preference Based Measure of Complementary Feeding Quality: Application to the Avon Longitudinal Study of Parents and Children

This paper presents the development of the Complementary Feeding Utility Index (CFUI), a composite index aimed to measure adherence to infant feeding guidelines. Through an axiomatic characterization this paper shows the advantages in using the CFUI are the following: it avoids the use of arbitrary cut-offs, and by converting observed diet preferences into utilities, summing the score is meaningful. In addition, as the CFUI is designed to be scored continuously, it allows the transition from intake of beneficial foods (in low quantities) and intake of detrimental foods (in high quantities) to be more subtle. The paper first describes the rationale being the development of the CFUI and then elaborates on the methodology used to develop the CFUI, including the process of selecting the components. The methodology is applied to data collected from the Avon Longitudinal Study of Parents and Children to show the advantages of the CFUI over traditional diet index approaches. Unlike traditional approaches, the distribution of the CFUI does not peak towards mean value but distributes evenly towards the tails of the distribution.     

Diagnosis of gastric cancer.

A prospective comparison was made of the accuracy of different diagnostic methods for gastric cancer. The basis of the study was a consecutive series of 113 patients thought to have gastric pathology; cancer was the final diagnosis in 32. Endoscopy and radiology were the most accurate investigations, whereas biopsy, cytology, and clinical examination gave disappointing results. A wide range of clinical features and laboratory investigations were studied in all patients in an attempt to identify criteria suggestive of malignancy. Multifactorial computer analysis of these investigations failed to improve upon the radiological diagnosis. A systemic approach designed to make optimal use of limited endoscopic and histopathological resources in the diagnosis of gastric lesions is presented.