Characterization of GMP-17, a granule membrane protein that moves to the plasma membrane of natural killer cells following target cell recognition.

Cytotoxic lymphocytes are characterized by their inclusion of cytoplasmic granules that fuse with the plasma membrane following target cell recognition. We previously identified a cytotoxic granule membrane protein designated p15-TIA-1 that is immunochemically related to an RNA-recognition motif (RRM)-type RNA-binding protein designated p40-TIA-1. Although it was suggested that p15-TIA-1 might be derived from p40-T1A-1 by proteolysis, N-terminal amino acid sequencing of p15-TIA-1 immunoaffinity purified from a natural killer (NK) cell line by using monoclonal antibody (mAb) 2G9 revealed that p15-T1A-1 is identical to the deduced amino acid sequence of NKG7 and GIG-1, cDNAs isolated from NK cells and granulocyte-colony-stimulating factor-treated mononuclear cells, respectively. Epitope mapping revealed that mAb 2G9 recognizes the C terminus of p15-T1A-1 and p40-T1A-1. The deduced amino acid sequence of p15-T1A-1/NKG7/GIG-1 predicts that the protein possesses four transmembrane domains, and immuno-electron microscopy localizes the endogenous protein to the membranes of cytotoxic granules in NK cells. Given its subcellular localization, we propose to rename-this protein GMP-17, for granule membrane protein of 17 kDa. Immunofluorescence microscopy of freshly isolated NK cells confirms this granular localization. Target cell-induced NK cell degranulation results in translocation of GMP-17 from granules to the plasma membrane, suggesting a possible role for GMP-17 in regulating the effector function of lymphocytes and neutrophils.     

Small bowel CT‐enteroclysis: Technique,pitfalls and pictorial review

Computed tomography small bowel enteroclysis has been carried out at Noosa Hospital since July 2003, and more recently at St George Private Hospital, Kogarah. Over 125 cases have been carried out. This article describes the different techniques, the pitfalls and a pictorial review of small bowel pathology.     

Serum apolipoproteins A-I and B in male and female full-term new borns of the Toledo study (Spain)

Cord serum apolipoproteins (Apo) A-I and B from 548 healthy, full-term singletons were studied. Females displayed slightly, but significantly, higher Apo A-I levels ( p < 0.001) than males. Particularly at weeks 38 and 39 ( p < 0.05), whereas Apo B was not gender affected but likewise increased ( p < 0.05) between weeks 37 and 41. Apo A-I values increased ( p < 0.05) with gestational age in males, but with birthweight in females. Results suggest that small gender and age-related metabolic differences exist at birth in terms infants     

Undergraduate attitudes to exposure to an NHSresource allocation problem

Service community physicians are involved in the teaching of medical undergraduates in Newcastle upon Tyne at an early stage in their course. They teach in a Health Service project. One such project is described, together with attitudes emerging from a limited evaluation. The results are largely favourable and encourage perseverance with the theme.     

Molecular analysis of argininosuccinate synthetase deficiency in human fibroblasts.

We have analyzed cultured skin fibroblasts derived from patients with argininosuccinate synthetase deficiency for alterations in gene structure, mRNA content, and protein structure. Genomic DNA was digested with the endonucleases EcoRI or HindIII, and the fragments were analyzed by Southern blotting and hybridization with a cDNA probe for argininosuccinate synthetase. The blot pattern is complex because there are at least 10 copies of argininosuccinate synthetase-like genes scattered over multiple human chromosomes. All nine patients studied showed patterns of DNA fragments that were indistinguishable from the normal control cell lines, and despite the possibility that the complexity could mask some changes, major deletions of the active gene(s) were not present. Blot hybridization of RNA indicated the presence of hybridizable mRNA of approximately normal size in seven of seven individuals examined with a suggestion of some heterogeneity. Analysis of enzyme antigen by protein transfer from NaDodSO4 containing polyacrylamide gels revealed considerable heterogeneity. This analysis revealed no cross-reacting material (CRM) in nine cell lines, CRM of normal molecular weight in one cell line, and CRM of reduced molecular weight in one cell line. These findings suggest that the genes for argininosuccinate synthetase in most citrullinemia patients are transcribed and produce stable mRNA. These mRNA either are not translated, or the translation product (enzyme) is rapidly degraded or is immunologically nonreactive. Defective gene expression in this disorder appears to involve abnormal mRNA, which may be altered by point mutations, frame shift mutations, deletions, insertions or particularly by abnormal RNA processing.