Inflammation in areas of fibrosis: The DeKAF prospective cohort

Inflammation in areas of fibrosis (i‐IFTA) in posttransplant biopsy specimens has been associated with decreased death‐censored graft survival (DC‐GS). Additionally, an i‐IFTA score ≥ 2 is part of the diagnostic criteria for chronic active TCMR (CA TCMR). We examined the impact of i‐IFTA and t‐IFTA (tubulitis in areas of atrophy) in the first biopsy for cause after 90 days posttransplant (n = 598); mean (SD) 1.7 ± 1.4 years posttransplant. I‐IFTA, present in 196 biopsy specimens, was strongly correlated with t‐IFTA, and Banff i. Of the 196, 37 (18.9%) had a previous acute rejection episode; 96 (49%) had concurrent i score = 0. Unlike previous studies, i‐IFTA = 1 (vs 0) was associated with worse 3‐year DC‐GS: (i‐IFTA = 0, 81.7%, [95% CI 77.7 to 85.9%]); i‐IFTA = 1, 68.1%, [95% CI 59.7 to 77.6%]; i‐IFTA = 2, 56.1%, [95% CI 43.2 to 72.8%], i‐IFTA = 3, 48.5%, [95% CI 31.8 to 74.0%]). The association of i‐IFTA with decreased DC‐GS remained significant when adjusted for serum creatinine at the time of the biopsy, Banff i, ci and ct, C4d and DSA. T‐IFTA was similarly associated with decreased DC‐GS. Of these indication biopsies, those with i‐IFTA ≥ 2, without meeting other criteria for CA TCMR had similar postbiopsy DC‐GS as those with CA TCMR. Those with i‐IFTA = 1 and t ≥ 2, ti ≥ 2 had postbiopsy DC‐GS similar to CA TCMR. Biopsies with i‐IFTA = 1 had similar survival as CA TCMR when biopsy specimens also met Banff criteria for TCMR and/or AMR. Studies of i‐IFTA and t‐IFTA in additional cohorts, integrating analyses of Banff scores meeting criteria for other Banff diagnoses, are needed.     

Dose--response curve for ethylnitrosourea-induced specific-locus mutations in mouse spermatogonia.

The extreme mutagenic effectiveness of N-ethyl-N-nitrosourea in the mouse has permitted the accumulation of the most extensive dose--response data yet obtained for chemical induction of specific-locus mutations in spermatogonia. In the lower portion of the curve, below a dose of 100 mg/kg, the data fall statistically significantly below a maximum likelihood fit to a straight line. Independent evidence indicates that, over this dose range, ethylnitrosourea reaches the testis in amounts directly proportional to the injected dose. It is concluded that, despite the mutagenic effectiveness of ethylnitrosourea, the spermatogonia are apparently capable of repairing at least a major part of the mutational damage when the repair process is not swamped by a high dose. This finding is important both in basic studied on the mutagenic action of chemicals in mammals and in risk estimation.     

大鼠眼外肌成肌细胞的增殖及分化特征

目的:完善眼外肌成肌细胞体外培养、鉴定的方法及观察其生物学特性。方法:实验于2005-02/08在青岛大学医学院附院中心实验室(省级实验室)完成。取出生后3～7d的大鼠,通过大鼠眼外肌细胞的取材、分离、消化、培养等技术,观察细胞的形态、生长曲线、细胞融合率,观察大鼠眼外肌卫星细胞的增殖与分化能力,利用成肌细胞标记物α-横纹肌肌动蛋白、中间丝结蛋白免疫细胞化学染色对所获得的细胞进行鉴定。结果:①成肌细胞的生长情况:在生长培养基作用下,细胞增殖旺盛;在分化培养基条件下,细胞分化良好,可融合成肌管。②成肌细胞融合率:在24h和48h融合率提高明显,72h达高峰,之后不再变化。③细胞免疫化学检测结果:α-横纹肌肌动蛋白和中间丝结蛋白免疫细胞化学染色阳性。结论:体外培养的大鼠眼外肌卫星细胞具有良好的增殖与分化能力,其生物学特征同骨骼肌卫星细胞。     

Chlorambucil effectively induces deletion mutations in mouse germ cells.

The chemotherapeutic agent chlorambucil was found to be more effective than x-rays or any chemical investigated to date in inducing high yields of mouse germ-line mutations that appear to be deletions or other structural changes. Induction of mutations involving seven specific loci was studied after exposures of various male germ-cell stages to chlorambucil at 10-25 mg/kg. A total of 60,750 offspring was scored. Mutation rates in spermatogonial stem cells were not significantly increased over control values; this negative result is not attributable to selective elimination of mutant cells. Mutations were, however, clearly induced in treated post-stem-cell stages, among which marked variations in mutational response were found. Maximum yield occurred after exposure of early spermatids, with approximately 1% of all offspring carrying a specific-locus mutation in the 10 mg/kg group. The stage-response pattern for chlorambucil differs from that of all other chemicals investigated to date in the specific-locus test. Thus far, all but one of the tested mutations induced by chlorambucil in post-stem-cell stages have been proved deletions or other structural changes by genetic, cytogenetic, and/or molecular criteria. Deletion mutations have recently been useful for molecular mapping and for structure-function correlations of genomic regions. For generating presumed large-lesion germ-line mutations at highest frequencies, chlorambucil may be the mutagen of choice.     

The regulation of hemopoiesis in long-term bone marrow cultures. II. Stimulation and inhibition of stem cell proliferation

The isolation of a DNA synthesis inhibitor (NBME fraction IV) and stimulator (RBME fraction III) specific for the hemopoietic stem cell (CFU-s) from freshly isolated normal adult and regenerating murine bone marrow, respectively, has been well documented. We have utilized long- term liquid bone marrow cultures in a further analysis of the role of these factors in the regulation of CFU-s proliferation. Our results show that shortly after feeding, at a time when the cultured CFU-s are actively proliferating, high levels of the hemopoietic stem cell proliferation stimulator fraction III can be isolated from the culture medium. In contrast, the presence of essentially noncycling CFU-s found in cultures fed 8-10 days previously correlates with high levels of the hemopoietic stem cell inhibitor fraction IV. These results suggest that a certain balance between these factors determines CFU-s proliferation in the long-term cultures. In support of this, DNA synthesis in actively cycling CFU-s in the long-term cultures is inhibited for at least 3 days by the addition of excess NBME fraction IV (inhibitor). Furthermore, DNA synthesis in noncycling cultured CFU-s is stimulated for at least 5 days by the addition of RBME fraction III (stimulator).