Kidney transplants in mice. An analysis of the immune status of mice bearing long-term, H-2 incompatible transplants

Kidney transplants between strains of mice which are incompatible at either the K or the D end of the H-2 complex usually function for prolonged periods supporting the lives of nephrectomized recipients. This occurs with no recipient treatment. With multiple H-2 and non-H-2 determined incompatibilities, transplants may be rejected but more slowly than skin grafts. In the strain combination studied most extensively in these experiments (B10.D2 to B6AF(1)) in which the incompatibility was confined to the K end of the H-2 region, about 70 percent of recipients survived for many weeks with normal blood urea nitrogen levels. Skin grafts between untreated members of these strains were rejected promptly (mean survival time of 13.5 +/- 1.1 days) as were kidney transplants to recipients of prior skin grafts. Donor strain skin grafts to recipients of kidney transplants after kidney transplantation enjoyed greatly prolonged survival whereas skin grafts from a third party (A.SW) were rejected normally. If kidney tissue was transferred in the form of free grafts without primary vascular union, it was rejected promptly leaving its recipient highly immunized. Cellular and humoral immunity to donor antigens declined over the first few weeks after transplantation, and the spleens of long-term recipients contained no “killer cells.” Recipient lymphoid cells could mount active graft versus host reactions to donor strain antigens on transfer to neonatal mice. Nevertheless, they were distinctly less able to respond specifically by the production of killer cells to donor strain antigens after sensitization in vitro. No evidence that this defect was associated with the presence of suppressor cells was forthcoming from several types of in vivo and in vitro tests.     

Outcome of initially nonoperative treatment for acute simple appendicitis in children

Purpose

To compare the outcome of initially nonoperative treatment with immediate appendectomy for simple appendicitis in children.

Regulation of murine macrophage Ia-antigen expression by products of activated spleen cells

This investigation examined the effects of mediators derived form activated spleen cells on macrophage Ia-antigen expression and function. Incubation of adherent thioglycollate-induced murine peritoneal macrophages(> 90% Ia-) with concanavalin A (Con A)- stimulated spleen cell supernate (Con A sup) resulted in a dose- dependent increase in the percentage of Ia-containing (Ia+) phagocytic cells, as detected by antiserum-and-complement-mediated cytotoxicity. The Ia-antigen expression of macrophages incubated with unstimulated spleen cell supernate supplemented with Con A (Control sup) declined. Pretreatment of the macrophages with anti-Ia and complement before addition of the Con A sup did not inhibit subsequent Ia-antigen expression, suggesting that Ia- macropohages were converted to Ia+ cells. These findings were not a result of adsorption of soluble Ia- antigen from the Con A sup, because Ia-antigen expression was detected by an antiserum specific for the haplotype of the macrophages but not that of the allogeneic spleen cells from which the supernate was prepared. Con A sup-cultured macrophages also stimulated the proliferation of allogeneic spleen cells significantly better than Control sup-cultured macrophages in the mixed leukocyte reaction (MLR). Pretreatment of Con A sup-cultured macrophages with anti-Ia and complement before addition of splenic responder cells abrogated their stimulatory capacity, indicating the Ia dependence of the MLR. We hypothesize that regulatory lymphokine(s) can induce both the expression of the Ia+ phenotype by macrophages and the functional capability to stimulate the MLR, and that macrophages lose these capabilities in the absence of such mediator(s).     

Polycystic Kidney Disease Re-evaluated: A Population-based Study

A genetic register of all known cases of autosomal dominantpolycystic kidney disease occurring in South and Mid-Wales hasbeen established. In a population of 2.1 million, 209 familieswith affected members were identified, 303 of whom are currentlyalive, 70 on renal replacement therapy. An additional 551 caseswould be predicted amongst family members at 50 per cent and25 per cent risk, giving an apparent prevalence of 1:2459 inthe general population. Five possible new mutations were seenwhere adults with phenotypic autosomal dominant polycystic kidneydisease had both parents alive, age > 55 years with no cystsvisible on ultrasound. The take-on rate for renal replacementtherapy increased during 1970–79 but has apparently reacheda plateau of 4.8 cases per million population per year overthe last 8 years, despite a rapidly increasing acceptance ofuraemic patients as a whole (72/10⁶/year in 1988–89).Considerably more patients with autosomal dominant polycystickidney disease aged over 50 years were started on treatmentin 1980–89 than in 1970–79, but the survival overallimproved with time. All cases of autosomal dominant polycystickidney disease reaching end-stage renal disease are now beingtreated, but the apparent clinical prevalence of this conditionin our region is less than half the supposed gene frequency,suggesting that undiagnosed cases have a benign prognosis.     

Finding maximal transcriptome differences between reprotoxic and non-reprotoxic phthalate responses in rat testis

The chemical legislation of the EU, Registration, Evaluation, and Authorization of Chemicals (REACH), stipulates that about 30 000 chemical substances are to be assessed on their possible risks. Toxicological evaluation of these compounds will at least partly be based on animal testing. In particular, the assessment of reproductive toxicity is a very complicated, time‐consuming and animal‐demanding process. Introducing microarray‐based technologies can potentially refine in vivo toxicity testing. If compounds of a distinct chemical class induce reproducible gene‐expression responses with a recognizable overlap, these gene‐expression signatures may indicate intrinsic features of certain compounds, including specific toxicity. In the present study, we have set out the first steps towards this approach for the reproductive toxicity of phthalates. Male rats were treated with a single dose of either reprotoxic or non‐reprotoxic phthalates, and were analyzed 24 h afterwards. Subsequently, histopathological and gene‐expression profiling analyses were performed. Despite ambiguous histopathological observations, we were able to identify genes with differential expression profiles between the reprotoxic phthalates and the non‐reprotoxic counterparts. This shows that differences in gene‐expression profiles, indicative of the type of exposure, may be detected earlier, or at lower doses, than classical pathological endpoints. These findings are promising for ‘early warning’ biomarker analyses and for using toxicogenomics in a category approach. Ultimately, this could lead to a more cost‐effective approach for prioritizing the toxicity testing of large numbers of chemicals in a short period of time in hazard assessment of chemicals, which is one of the objectives of the REACH chemical legislation. Copyright © 2010 John Wiley & Sons, Ltd.     

HDAC6 Deacetylates Ku70 and Regulates Ku70-Bax Binding in Neuroblastoma

Ku70 was first characterized as a nuclear factor that binds DNA double-strand breaks in nonhomolog end-joining DNA repair. However, recent studies have shown that Ku70 is also found in the cytoplasm and binds Bax, preventing Bax-induced cell death. We have shown that, in neuroblastoma cells, the binding between Ku70 and Bax depends on the acetylation status of Ku70, such that, when Ku70 is acetylated, Bax is released from Ku70, triggering cell death. Thus, to survive, in neuroblastoma cells, cytoplasmic Ku70 acetylation status is carefully regulated such that Ku70 is maintained in a deacetylated state, keeping Bax complexed with Ku70. We have shown that overexpression of CREB-binding protein (CBP), a known acetyltransferase that acetylates Ku70, releases Bax from Ku70, triggering apoptosis. Although we have shown that blocking deacetylase activity using non-type-specific inhibitors also triggers Ku70 acetylation and Bax-dependent cell death, the targets of these deacetylase inhibitors in neuroblastoma cells remain unknown. Here, we demonstrate that, in neuroblastoma cells, histone deacetylase 6 (HDAC6) binds Ku70 and Bax in the cytoplasm and that knocking down HDAC6 or using an HDAC6-specific inhibitor triggers Bax-dependent cell death. Our results show that HDAC6 regulates the interaction between Ku70 and Bax in neuroblastoma cells and may be a therapeutic target in this pediatric solid tumor.