Recruitment of ATR to sites of ionising radiation-induced DNA damage requires ATM and components of the MRN protein complex.

ATM and ATR are two related kinases essential for signalling DNA damage. Although ATM is thought to be the principle kinase responsible for signalling ionising radiation (IR)-induced DNA damage, ATR also contributes to signalling this form of genotoxic stress. However, the molecular basis of differential ATM and ATR activation in response to IR remains unclear. Here, we report that ATR is recruited to sites of IR-induced DNA damage significantly later than activation of ATM. We show that ATR is recruited to IR-induced nuclear foci in G(1) and S phase of the cell cycle, supporting a role for ATR in detecting DNA damage outside of S phase. In addition, we report that recruitment of ATR to sites of IR-induced DNA damage is concomitant with appearance of large tracts of single-stranded DNA (ssDNA) and that this event is dependent on ATM and components of the Mre11/Rad50/Nbs1 (MRN) protein complex.

Alleviation of experimental cyclosporin A nephrotoxicity by low dose aspirin in the rat.

Groups of male Sprague-Dawley rats received either cyclosporin A (CsA; 25 mg/kg by gavage), low dose aspirin (ASP; 20 mg/kg by gavage), a combination of both, or the appropriate drug vehicles daily for 14 days. Renal structure and function were assessed on day 0 (pretreatment) and on days 7 and 14. Compared to pretreatment results, CsA nephrotoxicity was characterized by increased plasma urea and creatinine concentrations and by moderate to severe microcalcification (MC) at the corticomedullary junction by day 14. The development of nephrotoxicity was also associated with a 5-fold increase in urine thromboxane B2 (TxB2) excretion by day 10, while that of 6-ketoprostaglandin F1 alpha remained relatively constant. Although both ASP and saline (ASP vehicle) -cotreated animals demonstrated significantly lower plasma urea and creatinine concentrations compared to treatment with CsA alone, the severity of MC observed on day 14, was reduced only in the ASP cotreatment group. Though whole blood CsA concentrations were similar at around 2400 ng/mL in all experimental groups. In addition, although a 2-fold increase in urine TxB2 excretion was observed on days 7 and 10 following treatment with CsA/ASP, levels were significantly reduced compared to treatment with either CsA alone or CsA/saline (both P < 0.05).

Association of TNF-α-857C with Inflammatory Bowel Disease in the Australian Population.

BACKGROUND: It is now well established that susceptibility to inflammatory bowel disease is in part genetic, with one localization on chromosome 6 (IBD3) having been replicated in a number of populations. A candidate in that region, TNF-α, contains polymorphisms in the promoter region that appear to be associated with disease. METHODS: More than 600 individuals from 170 multiplex IBD families were genotyped for four polymorphisms in the TNF-α gene and analysed for association. RESULTS AND CONCLUSION: A strong association was observed between transmission of the -857 C allele and disease. This effect was strongest in those families in which the NOD2 risk alleles are also segregating, supporting the existence of an interaction between IBD3 and IBD1 on chromosome 16.

Evaluation of the ID-gel test for antibody screening and identification.

A gel technique for the detection of red blood cell (rbc) antigen-antibody reactions was evaluated for use in antenatal antibody screening and identification procedures. The evaluation was undertaken on 3,900 random antenatal samples. Results obtained in the gel test system were compared with those obtained from parallel testing using conventional serological methods. The ID gel system detected 148 (3.7%) red cell antibodies, compared with 95 (2.4%) using traditional techniques. The number of non-specific antibodies and false-positive screens were reduced using the gel test system. Antibody titres performed using the gel system were more sensitive than with our tube IAT method. The gel system was easy to use and gave reliable, reproducible results. Antibody detection rates were enhanced compared with our existing routine techniques.

Association of TNF-alpha-857C with inflammatory bowel disease in the Australian population.

BACKGROUND: It is now well established that susceptibility to inflammatory bowel disease is in part genetic, with one localization on chromosome 6 (IBD3) having been replicated in a number of populations. A candidate in that region, TNF-alpha, contains polymorphisms in the promoter region that appear to be associated with disease. METHODS: More than 600 individuals from 170 multiplex IBD families were genotyped for four polymorphisms in the TNF-alpha gene and analysed for association. RESULTS AND CONCLUSION: A strong association was observed between transmission of the -857 C allele and disease. This effect was strongest in those families in which the NOD2 risk alleles are also segregating, supporting the existence of an interaction between IBD3 and IBD1 on chromosome 16.

Longitudinal analysis of the relationship between serum insulin-like growth factor-I and radiographic knee osteoarthritis.

OBJECTIVE: To examine the relation between serum insulin-like growth factor I (IGF-I) levels and both incident and progressive radiographic knee osteoarthritis (OA) in the Framingham Osteoarthritis Study. DESIGN: Subjects had bilateral weight-bearing, anterior-posterior knee radiographs performed in 1983-1985 and again in 1992-1993. IGF-I levels were measured from blood specimens obtained in 1988-1989 by a competitive binding radio-immunoassay (RIA) after separation with octadecasilyl-silica cartridges of serum IGF-I from binding proteins. Participants without baseline radiographic OA [Kellgren and Lawrence grades (K&L) = 0-1] were classified as having incident disease if they had K&L > or = 2 grades at follow-up. Progressive OA was defined as an increase in K&L score of > or = 1 in knees with baseline OA (K&L > or = 2). All analyses were knee-based and sex-specific. We examined IGF-I tertiles in relation to the risk of incident and progressive radiographic OA separately, adjusting for age, body mass index (BMI), and baseline K&L score, and used generalized estimating equations to adjust for the correlation between fellow knees. RESULTS: Four hundred and forty-one participants had knee radiographs and serum IGF-I levels measured. No associations were found for serum IGF-I levels and incident [women: OR = 0.9 (0.6-1.7), men OR = 1.2 (0.6-2.6)] or progressive [women OR = 0.9 (0.6-1.6), men OR = 0.9 (0.3-3.0)] radiographic knee OA in either sex. Neither did we observe any association between IGF-I and worsening of individual radiographic features of OA (i.e., osteophyte growth and joint space loss). CONCLUSION: In summary, this longitudinal study did not demonstrate any association of serum IGF-I and incident or progressive radiographic knee OA. Further studies are needed to clarify the role of IGF-I in OA.

CARD15/NOD2 risk alleles in the development of Crohn's disease in the Australian population.

We have previously reported strong evidence for linkage between IBD1 and Crohn's disease (CD) in Australian Crohn's disease families. Three risk alleles for Crohn's disease, (Arg702Trp (C/T), Gly908Arg (G/C) and 980fs981 (-/C), were recently identified in the CARD15/NOD2 gene on chromosome 16, implicating this as the IBD1 locus. Using a novel diagnostic PCR-RFLP, we have examined the frequency of these alleles in 205 multiplex IBD families, 107 sporadic Crohn's disease cases and 409 normal individuals. We demonstrate that the three risk alleles are more frequent in Crohn's disease, than in controls, with allelic frequencies of 0.11, 0.02 and 0.07 respectively. Heterozygosity for individual variants conferred a three-fold increase in risk for Crohn's disease while substantially higher risks were associated with being homozygous or compound heterozygous. Despite a significantly lower population allele frequency for the frameshift mutation than reported by other groups, we see a similar contribution by this allele to the risk of developing Crohn's disease. While the three risk alleles influence susceptibility to Crohn's disease in Australia, we show that these alleles do not fully explain the linkage evidence and suggest that there are very likely additional IBD1 susceptibility alleles yet to be described in Australian CD at the NOD2 locus. We also show a second linkage peak in Australian CD that provides some support for a second disease susceptibility locus on chromosome 16.