Instability in the faecal flora of a patient suffering from food-related irritable bowel syndrome

The faecal microbial flora of a patient with severe irritable bowel syndrome related to multiple food intolerances was very variable and contained a high proportion of facultative bacteria and an unusual incidence of Clostridium species.     

An SH2-domain-containing kinase negatively regulates the phosphatidylinositol-3 kinase pathway

SHK1 is a novel dual-specificity kinase that contains an SH2 domain in its C-terminal region. We demonstrate that SHK1 is required for proper chemotaxis and phagocytosis. Mutant shk1 null cells lack polarity, move very slowly, and exhibit an elevated and temporally extended chemoattractant-mediated activation of the kinase Akt/PKB. GFP fusions of the PH domain of Akt/PKB or the PH-domain-containing protein CRAC, which become transiently associated with the plasma membrane after a global stimulation with a chemoattractant, remain associated with the plasma membrane for an extended period of time in shk1 null cells. These results suggest that SHK1 is a negative regulator of the PI3K (phosphatidylinositol-3 kinase) pathway. Furthermore, when a chemoattractant gradient is applied to a wild-type cell, these PH-domain-containing proteins and the F-actin-binding protein coronin localize to its leading edge, but in an shk1 null cell they become randomly associated with the plasma membrane and cortex, irrespective of the direction of the chemoattractant gradient, suggesting that SHK1 is required for the proper spatiotemporal control of F-actin levels in chemotaxing cells. Consistent with such functions, SHK1 is localized at the plasma membrane/cortex, and we show that its SH2 domain is required for this localization and the proper function of SHK1.     

A comparison of anorexia nervosa and affective psychosis in young females

In a retrospective case note study, 73 young females with anorexia nervosa were compared with 88 young females with affective psychosis. These groups of patients did not differ in terms of place of residence, birth order or social class. They differed very significantly, however, in terms of age at onset of symptoms, marital status, educational attainments and in the pattern of family histories of psychiatric illness. It is concluded that anorexics and young females with affective disorders are two quite distinct groups of patients.     

Cytokines and T cells in host defense

Soluble and cell-bound ligands profoundly influence the differentiative fate of lymphocytes during an immune response. Recent advances have been made in understanding the role of cytokine signals and costimulatory signals in the regulation of T cell responses associated with resistance or susceptibility to infection. There has also been recent progress in defining the requirements for the generation and maintenance of immunologic memory, a critical component of adaptive immunity.     

Numerical index of the discriminatory ability of typing systems: an application of Simpson''s index of diversity.

An index of discrimination for typing methods is described, based on the probability of two unrelated strains being characterized as the same type. This index may be used to compare typing methods and select the most discriminatory system.     

Functional characterization of the early and late mRNAs of simian virus 40.

We have characterized the early SV40 mRNAs by size fractionation on acrylamide gels followed by in vitro translation and immunoprecipitation. The mRNA for the 17K T antigen migrates more slowly than that for the 100K T antigen, with the apparent size difference being 250 nucleotides This finding is consistent with the mRNA for the 17K T antigen corresponding to an almost complete copy of the early region while the mRNA for the 100K T antigen would lack the sequences between 0.59 and 0.54 map unit. By in vitro translation of SV40-specific RNA followed by immunoprecipitation we have been unable to detect the synthesis of any T antigen intermediate in size between the 100K and 17K T antigens. We have demonstrated the synthesis of two proteins from intracellular SV40-specific mRNAs which appear to be identical to the VP2 and VP3 found in the virion on the basis of their mobilities in acrylamide gels and their tryptic peptide maps. Both VP2 and VP3 are labeled with formyl-[³⁵S]methionine when synthesized in the presence of [³⁵S]fMet-tRNA_f^Met. By analyzing partial proteolysis products of such N-terminally labeled proteins we could show that VP2 and VP3 share common C-termini. Therefore, VP3 is initiated and made independently of VP2 and is not derived from VP2 by proteolytic processing. VP2 and VP3 are both made from mRNAs about 19 S in size. The mRNA for VP2 migrates marginally more slowly than the mRNA for VP3 in acrylamide gels.     

Problems affecting performance of the fluorescent treponemal antibody-absorption test for syphilis.

Immunofluorescent staining of Treponema pallidum was studied to clarify the effect of three factors on the results of the fluorescent treponemal antibody-absorption test: (i) heat inactivation of sera at 56 degrees C for 30 min before testing, (ii) use of multicircle slides, and (iii) tungsten illumination to visualize and assess unstained treponemes on reactive as well as nonreactive smears. It was found that serum inactivation before testing was not necessary for detection of immunoglobin G antibody, but an immunoglobulin M prozone was detected in unheated serum. On multicircle slides, it was demonstrated that a false-positive reaction could be obtained in 30 s at 37 and 25 degrees C if a smear where a nonreactive serum had been placed was crossed by a strongly reactive serum from another circle. Tungsten illumination proved necessary for correct assessment of unstained treponemes on all fluorescent treponemal antibody-aborption test smears, reactive or nonreactive. The possible role of these factors in incorrect fluorescent treponemal antibody-absorption test results is discussed.