Natural polyclonality of spontaneous AKR leukemia and its consequences for so-called specific immunotherapy.

Young female AKR mice made leukemic by iv inoculation of 10(3) spontaneous AKR thymoma cells were treated with repeated injections of irradiated cells from the same tumor. Treatment began 1 day after injection of the viable cells. The cytotoxicity of sera and lymphoid cells from healthy mice immunized with lymphoma cells from either treated or nontreated mice with leukemia grafts revealed that the tumor cells could be subdivided into four distinct antigenic types. One type (clone A) accounted for about 97% of the lymphoma cells in each mouse with spontaneous leukemia, whereas the remaining 3% were subdivided into three other distinct antigenic types (clones B, C, and D). Lymphoma cells from treated mice with grafted leukemia were never clone A type but either clone B, C, or D type. Repeated sc injections of 10(7) irradiated cells from spontaneous AKR thymomas induced from 15 to 34% cure in mice with grafts of leukemia cells. Treatment with only clone A induced about 32% cure, whereas treatment with clone B, C, or D had no beneficial effect. Treatment with 10(7) cells each of clone A plus clone B gave 33% cure; clone A plus clone B plus clone C, 45%; and all four clones cured 92% of the mice with leukemia grafts. The efficiency of immunotherapy may be influenced by the natural clonality of the tumor to be treated.     

Prophylactive treatment with flunisolide after polypectomy

Twenty-two patients with nasal polyps completed a double-blind study with a new topical corticosteroid, flunisolide. Treatment during three months after operation gave, in comparison with placebo, a statistically significant effect on the symptom of stuffy nose, and on the sum of scores for stuffy nose, runny nose and sneezing. There was no significant effect on rhinomanometry. Side effects were negligible. Three patients in the placebo-group required a further operation within one year but none in the flunisolide group. Prophylactic treatment with flunisolide can be recommended as a complement to other treatment after surgery of nasal polyps.     

DEAE-dextran enhancement of in vivo infection with murine leukemia virus

Summary Intraperitoneal administration of 25 g DEAE-dextran to mice receiving either Rauscher or B₁ leukemia virus subcutaneously enhanced the amount of virus recovered from spleen, thymus and serum three weeks later by 2 to 140 times.The virus titre was found one to two log higher in spleens than in thymus and serum whether the infection was accompanied by DEAE-dextran inoculation or not.     

Use of monoclonal antibodies to identify cerebrospinal fluid lymphoblasts in children with acute lymphoblastic leukemia

The identification of small numbers of leukemic cells in the cerebrospinal fluid (CSF) presents a diagnostic problem in the treatment of children with acute lymphoblastic leukemia (ALL). We adapted a latex sphere rosetting technique to allow us to identify simultaneously cell surface markers and cell morphology in 199 CSF samples from 34 patients and 14 control subjects. In patients without leukemic meningitis, the majority of CSF lymphocytes (69%) were found to be mature T cells positive for OKT11. A much smaller number of cells (8%) were found to be B cells positive for la. In these children, only 3% of CSF lymphoid cells expressed the common acute lymphoblastic leukemia antigen (CALLA). Similar results were found in the control subjects. By contrast, 28 CSF samples from nine children with varying numbers of CSF lymphoblasts had much greater proportions of CALLA- and la-positive CSF cells (24% to 96%). Leukemic meningitis was present in one of these patients and later developed in four others. However, three patients with small numbers of lymphoblasts present but with low proportions of CALLA-positive CSF cells (less than 5%) subsequently had normal CSF examinations. We found the use of this rosetting technique valuable in providing information complementary to that obtained from cell morphology alone about the possible malignant nature of small numbers of lymphoblast-like CSF cells seen on cytocentrifuge preparations in children with ALL.     

Diphenylhydantoin-induced pure red cell aplasia

The pathogenesis of diphenylhydantoin-induced pure red cell aplasia was investigated in the case of a 32-year-old man who developed pure red cell aplasia while he was under treatment with diphenylhydantoin. The patient's serum IgG purified from serum drawn at the time of diagnosis suppressed normal allogeneic marrow colony-forming (CFU-E) and burst- forming (BFU-E) and autologous blood BFU-E growth in vitro only in the presence of diphenylhydantoin. This IgG-diphenylhydantoin complex had no effect on CFU-GM growth in vitro. Normal IgG or patient's IgG purified from serum drawn after the remission of red cell aplasia had no effect on erythroid colony formation in vitro in the presence of diphenylhydantoin. The IgG-diphenylhydantoin complex exerted no direct cytotoxic effect on normal marrow erythroblasts, CFU-E, and BFU-E, nor did it interfere with the action of erythropoietin on marrow erythroblasts. These studies suggest that diphenylhydantoin-induced red cell aplasia is immunologically mediated through an IgG inhibitor, which requires the presence of the drug to suppress erythroid colony formation in vitro. This inhibitor seems to exert its effect on erythroid progenitors at or beyond the stage of differentiation of CFU- E, but not on erythroblasts.     

Dietary calcium, phosphorus, vitamin D, dairy products and the risk of colorectal adenoma and cancer among French women of the E3N-EPIC prospective study

A protective effect of calcium and/or dairy products on colorectal cancer has been reported in epidemiological studies but the findings are considered inconsistent. In particular, it is unclear whether they act at a particular step of the adenoma-carcinoma sequence. To investigate the effect of dairy product consumption and dietary calcium, vitamin D and phosphorus intake on the adenoma-carcinoma sequence in the French E3N-EPIC prospective study. The population for the study of risk factors for adenomas was composed of 516 adenoma cases, including 175 high-risk adenomas, and of 4,804 polyp-free subjects confirmed by colonoscopy. The population for the colorectal cancer study was composed of 172 cases and 67,312 cancer-free subjects. Diet was assessed using a self-administered questionnaire completed at baseline. There was a trend of decreasing risk of both adenoma (ptrend=0.04) and cancer (ptrend=0.08) with increasing calcium intake, with RRs for adenoma and cancer of 0.80 (IC 95%=0.62-1.03) and 0.72 (95% CI=0.47-1.10), respectively, in the fourth quartile compared to the first. A protective effect of dairy products on adenoma (RRQ4 vs. Q1=0.80, 95% CI=0.62-1.05, ptrend=0.04) was observed and of milk consumption on colorectal cancer (RRQ4vs. Q1=0.54, 95% CI=0.33-0.89, ptrend=0.09), although the latter did not reach significance. Phosphorus intake also decreased the risk of adenoma (RRQ4 vs. Q1=0.70, 95% CI=0.54-0.90, ptrend=0.005). No vitamin D effect was identified. Our data support the hypothesis that calcium, dairy products and phosphorus exert a protective effect at certain steps of the adenoma-carcinoma sequence.     

The KCNQ channel opener retigabine inhibits the activity of mesencephalic dopaminergic systems of the rat

Homo- and heteromeric complexes of KCNQ channel subunits are the molecular correlate of the M-current, a neuron-specific voltage-dependent K(+) current with a well established role in control of neural excitability. We investigated the effect of KCNQ channel modulators on the activity of dopaminergic neurons in vitro and in vivo in the rat ventral mesencephalon. The firing of dopaminergic neurons recorded in mesencephalic slices was robustly inhibited in a concentration-dependent manner by the KCNQ channel opener N-(2-amino-4-(4-fluorobenzylamino)-phenyl) carbamic acid ethyl ester (retigabine). The effect of retigabine persisted in the presence of tetrodotoxin and simultaneous blockade of GABA(A) receptors, small-conductance calcium-activated K(+) (SK) channels, and hyperpolarization-activated (I(h)) channels, and it was potently reversed by the KCNQ channel blocker 4-pyridinylmethyl-9(10H)-anthracenone (XE991), indicating a direct effect on KCNQ channels. Likewise, in vivo single unit recordings from dopaminergic neurons revealed a prominent reduction in spike activity after systemic administration of retigabine. Furthermore, retigabine inhibited dopamine synthesis and c-Fos expression in the striatum under basal conditions. Retigabine completely blocked the excitatory effect of dopamine D(2) autoreceptor antagonists. Again, the in vitro and in vivo effects of retigabine were completely reversed by preadministration of XE991. Dual immunocytochemistry revealed that KCNQ4 is the major KCNQ channel subunit expressed in all dopaminergic neurons in the mesolimbic and nigrostriatal pathways. Collectively, these observations indicate that retigabine negatively modulates dopaminergic neurotransmission, likely originating from stimulation of mesencephalic KCNQ4 channels.     

Ethical perspectives on RNA interference therapeutics

RNA interference is a mechanism for controlling normal gene expression which has recently begun to be employed as a potential therapeutic agent for a wide range of disorders, including cancer, infectious diseases and metabolic disorders. Clinical trials with RNA interference have begun. However, challenges such as off-target effects, toxicity and safe delivery methods have to be overcome before RNA interference can be considered as a conventional drug. So, if RNA interference is to be used therapeutically, we should perform a risk-benefit analysis. It is ethically relevant to perform a risk-benefit analysis since ethical obligations about not inflicting harm and promoting good are generally accepted. But the ethical issues in RNA interference therapeutics not only include a risk-benefit analysis, but also considerations about respecting the autonomy of the patient and considerations about justice with regard to the inclusion criteria for participation in clinical trials and health care allocation. RNA interference is considered a new and promising therapeutic approach, but the ethical issues of this method have not been greatly discussed, so this article analyses these issues using the bioethical theory of principles of the American bioethicists, Tom L. Beauchamp and James F. Childress.