The CTLA-4 gene region of chromosome 2q33 is linked to, and associated with, type 1 diabetes. Belgian Diabetes Registry

Susceptibility to autoimmune insulin-dependent (type 1) diabetes mellitus is determined by a combination of environmental and genetic factors, which include variation in MHC genes on chromosome 6p21 (IDDM1) and the insulin gene on chromosome 11p15 (IDDM2). However, linkage to IDDM1 and IDDM2 cannot explain the clustering of type 1 diabetes in families, and a role for other genes is inferred. In the present report we describe linkage and association of type 1 diabetes to the CTLA-4 gene (cytotoxic T lymphocyte associated-4) on chromosome 2q33 (designated IDDM12). CTLA-4 is a strong candidate gene for T cell- mediated autoimmune disease because it encodes a T cell receptor that mediates T cell apoptosis and is a vital negative regulator of T cell activation. In addition, we provide supporting evidence that CTLA-4 is associated with susceptibility to Graves' disease, another organ- specific autoimmune disease.      

Conservation of receptor antagonist anti-tumor activity by epidermal growth factor receptor antibody expressed in transgenic corn seed

Recombinant protein production in plants such as corn is a promising means to generate high product yields at low comparable production cost. The anti-EGFR monoclonal antibody C225, cetuximab, is a well-characterized receptor antagonist antibody recently approved for the treatment of refractory colorectal cancer. We initiated a study to test and compare the functional activity of glycosylated and aglycosylated C225 produced in stable transgenic corn seed. Both corn antibodies were shown to be functionally indistinguishable from mammalian-derived C225 in demonstrating high-affinity binding to the EGF receptor, blocking of ligand-dependent signaling, and inhibiting cell proliferation. In addition, consistent with cetuximab, both corn antibodies possessed strong anti-tumor activity in vivo. Acute dose primate pharmacokinetic studies, however, revealed a marked increase in clearance for the glycosylated corn antibody, while the aglycosylated antibody possessed in vivo kinetics similar to cetuximab. This experimentation established that corn-derived receptor blocking monoclonal antibodies possess comparable efficacy to mammalian cell culture-derived antibody, and offer a cost effective alternative to large-scale mammalian cell culture production.     

Utilization of acidophil bodies in the diagnosis of recurrent hepatitis C infection after orthotopic liver transplantation.

BACKGROUND: The distinction between acute rejection and early recurrent hepatitis C infection (RHCV) in the setting of orthotopic liver transplantation is often difficult. In liver biopsies acidophil bodies and lobular hepatitis are used to suggest a diagnosis of RHCV over rejection, however, the reliability of this practice has not been established. Because portal tract changes in RHCV and rejection often overlap, we sought to determine whether the degree of hepatocyte acidophil body formation seen on liver biopsies could be used to distinguish between these two conditions. METHODS: Quantification of acidophil bodies was performed on liver biopsies in orthotopic liver transplant patients with RHCV (n = 10), non-hepatitis C orthotopic liver transplant patients with uncomplicated rejection episodes (n = 10) and non-transplant patients with chronic hepatitis C infection (n = 10). Hematoxylin and Eosin stained slides from all three groups were randomized and tissue segments 1.0 cm in length and of variable width (0.04-0.13 cm) were examined at 200x magnification in a blinded fashion by two pathologists in order to quantify the number of acidophil bodies/cm(2). Lobular chronic inflammation was also graded on a 0-3+ scale. RESULTS: Liver biopsies taken at the onset of RHCV exhibited 606 +/- 101 acidophil bodies/cm(2) (mean +/- standard error of mean, range 200-1390). These counts were significantly greater (P =.0061, paired 2-tailed t-test) than the 241 +/- 53 acidophil bodies/cm(2) (range 80-514) for acute rejection, and the 194 +/- 21 acidophil bodies/cm(2) (range 100-333) for non-liver transplant chronic hepatitis C infection (P =.0013). No difference in lobular inflammation between index RHCV and rejection biopsies was detected. CONCLUSIONS: Although there is overlap, on average there are twice as many acidophil bodies in the initial stage of RHCV when compared with acute rejection (average of 55 per linear cm in RHCV versus 21 per linear cm for rejection). Lobular inflammation was not a reliable indicator of the initial onset of RHCV.     

Detection of <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> Antigens in Urinary Proteins of Tuberculosis Patients

A sensitive sandwich enzyme-linked immunosorbent assay (ELISA) that can detect up to 0.5 ng of culture filtrate proteins (CFPs) of Mycobacterium tuberculosis strain H37Ra is described. This detection system features several special characteristics: (i) the use of CFPs from the H37Ra strain of Mycobacterium tuberculosis to generate capture and detection antibodies in rabbits and mice, respectively; (ii) affinity purification of CFP-reactive antibodies and selection of the antibody preparations for best performance in the sandwich ELISA system; and (iii) the use of urine-derived protein preparations for antigen detection. The sandwich ELISA could detect up to 0.5 ng of CFPs of the H37Ra strain of Mycobacterium tuberculosis. The assay did not detect antigens of Escherichia coli, Candida albicans or Saccharomyces cerivisiae but efficiently detected CFP preparations from nine different clinical isolates of Mycobacterium tuberculosis. Significant variations, however, were noted in the relative efficacy of the assay to detect CFPs from different clinical isolates of Mycobacterium tuberculosis. The procedure was utilized for detecting tubercular antigens in urine samples from 29 patients with confirmed (sputum-positive) tuberculosis and from 25 healthy controls. Significant levels of antigen could be detected in 22 of the 29 samples tested. Electronic Publication     

Contraceptive use among South Asian women attending general practices in southwest London.

A cross-sectional survey of contraceptive practices was conducted among 180 South Asian women aged 16 to 50 years, attending inner-city general practices. Overall prevalence of contraceptive use was 63% and ranged from 70% in South Asian teenagers, to only 50% in women over 30 who had completed their family. Thirteen per cent of women had had a termination of pregnancy Although contraceptive use in this group is increasing, it has not yet reached national levels.     

Goblet cell carcinoids of the appendix: immunophenotype and ultrastructural study

BACKGROUND: Goblet cell carcinoids of the appendix are rare neoplasms with uncertain biological behavior. OBJECTIVE: The aims of our study were to evaluate the immunophenotype of this neoplasm with cell cycle/cell proliferation markers and to understand their histogenesis with ultrastructural analysis using conventional carcinoids as a frame of reference. METHODS: Clinical data and archival pathologic material of all goblet cell carcinoids of the appendix recorded by the Saskatchewan Cancer Registry between 1970 and 1998 were reviewed and evaluated by light microscopy, histochemistry, immunohistochemistry, and electron microscopy. RESULTS: Seven cases of goblet cell carcinoids were identified among 110 cases of conventional carcinoids of the appendix. Histopathology revealed widespread infiltration of the periappendiceal fat in all cases, with extensive perineural invasion. The cells stained strongly positive for mucicarmine, periodic acid-Schiff, periodic acid-Schiff diastase, Alcian blue, cytokeratin, and carcinoembryonic antigen. Most cases were positive for synaptophysin. Increased expression of cell proliferation markers and cell cycle markers was observed. Expression of p53 was strong in one case. Electron microscopy demonstrated the presence of mucinous vacuoles of varying sizes and occasional membrane-bound neuroendocrine granules. CONCLUSIONS: Goblet cell carcinoids of the appendix arise from a pluripotent cell with divergent neuroendocrine and mucinous differentiation. These neoplasms are widely invasive; they demonstrate a high cellular proliferation rate and dysregulation of the cell cycle with up-regulation of cyclin D1 and p21, and down-regulation of p16. Complete removal of the tumor is recommended because of the unpredictable biological behavior of this tumor, which includes delayed local recurrences and lung metastases.     

Upregulation of KIR expression on murine bone marrow cells by paraformaldehyde fixed tumor cells

We have previously shown that the activation of mouse spleen NK cells by IL2 is markedly boosted if paraformaldehyde fixed tumor target cells are added during the activation phase. In the present study, we have shown that such a boosting effect is not seen if mouse bone marrow (BM) cells are used instead of spleen cells. Addition of fixed tumor cells (1:100 ratio of tumor cells to BM cells) however resulted in a marked increase in the expression of Ly49 molecules on BM cells. The enhancement of Ly49 expression was not seen if fixed allogeneic BM cells were added, suggesting that Ly49 upregulation was tumor specific. Expression of Ly49A as well as Ly49C isotypes were augmented by fixed tumor cells. Moreover, increased Ly49 expression was seen on cell populations expressing TCRbeta as well as NK1.1 markers. These results indicate that exposure to tumor cells may be an important factor regulating KIR expression on NK and T cells. Implications of these results are discussed.     

Storage of thawed cryoprecipitated AHF is better at room temperature than at 1 degree C to 6 degrees C for factor VIII content

Before November 1989, both the American Association of Blood Banks and the Food and Drug Administration required that thawed cryoprecipitated antihemophilic factor (AHF) should be used immediately or be stored at room temperature and administered within 6 hours. However, in November 1989, the American Association of Blood Banks changed the requirement for storage of thawed cryoprecipitated AHF from room temperature to 1 degree C to 6 degrees C, while the Food and Drug Administration still required thawed cryoprecipitated AHF to be stored at room temperature. The present study was designed to measure and compare the factor VIII activity in 10 bags of thawed cryoprecipitated AHF that were split into aliquots and stored at room temperature and at 1 degree C to 6 degrees C. At 6 and 24 hours after thawing, the mean factor VIII activities (% of normal) of the room temperature-stored cryoprecipitated AHF were 741% and 680% vs 650% and 608% for the 1 degree C- to 6 degrees C-stored cryoprecipitated AHF (P less than .05 at 6 hours and P = .11 at 24 hours). The storage of thawed cryoprecipitated AHF at 1 degree C to 6 degrees C also resulted in precipitation of both factor VIII and fibrinogen. These data show that it is better to store thawed cryoprecipitated AHF at room temperature vs 1 degree C to 6 degrees C for factor VIII activity. These data also suggest that adequate levels of factor VIII are maintained in thawed cryoprecipitated AHF that has been stored at room temperature for up to 24 hours.     

Racial differences in vitamin B12 levels in the United States

Studies from Africa have demonstrated that black people have higher vitamin B12 (cobalamin) levels than do white people. The authors compared healthy white people, black people, and Latin-Americans in the United States. Their study is also the largest in which the effect of race and sex on the cobalamin levels has been examined. Analysis of 233 healthy subjects showed that black people had significantly higher (P less than 0.0001) vitamin B12 levels than did white people. Latin-Americans had levels intermediate between those of white and black people, although their levels were significantly different only in comparison with white people (P = 0.0029). Based on the study of 305 healthy subjects, no sex difference in vitamin B12 levels was noted. Conflicting claims have been made on sex difference in the past. The authors conclude that there is a racial but not a sex difference in vitamin B12 levels in the United States. Like African black people, black people and Latin-Americans in this country have significantly higher vitamin B12 levels than do white people. This finding supports the thesis that genetic factors contribute to the racial differences in vitamin B12 levels.