Neonatal beta-cell apoptosis: a trigger for autoimmune diabetes?

In neonatal rodents, the beta-cell mass undergoes a phase of remodeling that includes a wave of apoptosis. Using both mathematical modeling and histochemical detection methods, we have demonstrated that beta-cell apoptosis is significantly increased in neonates as compared with adult rats, peaking at approximately 2 weeks of age. Other tissues, including the kidney and nervous system, also exhibit neonatal waves of apoptosis, suggesting that this is a normal developmental phenomenon. We have demonstrated that increased neonatal beta-cell apoptosis is also present in animal models of autoimmune diabetes, including both the BB rat and NOD mouse. Traditionally, apoptosis has been considered a process that does not induce an immune response. However, recent studies indicate that apoptotic cells can do the following: 1) display autoreactive antigen in their surface blebs; 2) preferentially activate dendritic cells capable of priming tissue-specific cytotoxic T-cells; and 3) induce the formation of autoantibodies. These findings suggest that in some circumstances physiological apoptosis may, in fact, initiate autoimmunity. Initiation of beta-cell-directed autoimmunity in murine models appears to be fixed at approximately 15 days of age, even when diabetes onset is dramatically accelerated. Taken together, these observations have led us to hypothesize that the neonatal wave of beta-cell apoptosis is a trigger for beta-cell-directed autoimmunity.     

Randomized trial of two intravenous schedules of the topoisomerase I inhibitor liposomal lurtotecan in women with relapsed epithelial ovarian cancer: a trial of the national cancer institute of Canada clinical trials group.

PURPOSE: Liposomal lurtotecan (OSI-211) is a liposomal formulation of the water-soluble topoisomerase I inhibitor lurtotecan (GI147211), which demonstrated superior levels of activity compared with topotecan in preclinical models. We studied two schedules of OSI-211 in a randomized design in relapsed ovarian cancer to identify the more promising of the two schedules for further study. PATIENTS AND METHODS: Eligible patients had measurable epithelial ovarian, fallopian, or primary peritoneal cancer that was recurrent after one or two prior regimens of chemotherapy. Patients were randomly assigned to receive either arm A (OSI-211 1.8 mg/m(2)/d administered by 30-minute intravenous infusion on days 1, 2, and 3 every 3 weeks) or arm B (OSI-211 2.4 mg/m(2)/d administered by 30-minute intravenous infusion on days 1 and 8 every 3 weeks). The primary outcome measure was objective response, which was confirmed by independent radiologic review, and a pick the winner statistical design was used to identify the schedule most likely to be superior. RESULTS: Eighty-one patients were randomized between October 2000 and September 2001. The hematologic toxic effects were greater on arm A than on arm B (grade 4 neutropenia, 51% v 22%, respectively), as was febrile neutropenia (26% v 2.4%, respectively). Of the 80 eligible patients, eight patients (10%) had objective responses; six responders (15.4%; 95% CI, 6% to 30%) were in arm A and two responders (4.9%; 95% CI, 1% to 17%) were in arm B. CONCLUSION: The OSI-211 daily for 3 days intravenous schedule met the statistical criteria to be declared the winner in terms of objective response. This schedule was also associated with more myelosuppression than the schedule of OSI-211 administered in arm B.     

Incidence and prognostic impact of amenorrhea during adjuvant therapy in high-risk premenopausal breast cancer: analysis of a National Cancer Institute of Canada Clinical Trials Group Study--NCIC CTG MA.5.

PURPOSE: To investigate the therapeutic impact of chemotherapy-induced amenorrhea in premenopausal patients with breast cancer. PATIENTS AND METHODS: We conducted a retrospective cohort study of a National Cancer Institute of Canada Clinical Trials Group phase III trial involving premenopausal patients randomized to receive cyclophosphamide, methotrexate, and fluorouracil (CMF), versus intensive cyclophosphamide, epirubicin, and fluorouracil (CEF). The objectives of our study were to describe the incidence of amenorrhea at 6 and 12 months post-random assignment and to determine the association of amenorrhea with relapse-free and overall survival. RESULTS: Data on 442 patients were used in our analyses. Despite the higher cumulative dose of cyclophosphamide in the CMF treatment arm, at 6 months post-random assignment, the rate of amenorrhea was higher in the CEF group (relative risk, 1.2; 95% CI, 1.0 to 1.3), with no difference at 12 months. In the receptor-positive subgroup, 6-month amenorrhea rates were not associated with prognosis. In contrast, amenorrhea at 12 months was significantly associated with relapse-free survival (hazard ratio, 0.51; 95% CI, 0.32 to 0.82; P = .005) and overall survival (hazard ratio, 0.40; 95% CI, 0.22 to 0.72; P = .002). CONCLUSION: Late chemotherapy-induced amenorrhea seems to be associated with improved outcome in patients with premenopausal, receptor-positive breast cancer.     

Amphetamine maintenance therapy during intermittent cocaine self-administration in rats attenuates psychomotor and dopamine sensitization and reduces addiction-like behavior

D-amphetamine maintenance therapy shows promise as a treatment for people with cocaine addiction. Preclinical studies using Long Access (LgA) cocaine self-administration procedures suggest D-amphetamine may act by preventing tolerance to cocaine’s effects at the dopamine transporter (DAT). However, Intermittent Access (IntA) cocaine self-administration better reflects human patterns of use, is especially effective in promoting addiction-relevant behaviors, and instead of tolerance, produces psychomotor, incentive, and neural sensitization. We asked, therefore, how D-amphetamine maintenance during IntA influences cocaine use and cocaine’s potency at the DAT. Male rats self-administered cocaine intermittently (5 min ON, 25 min OFF x10; 5-h/session) for 14 sessions, with or without concomitant D-amphetamine maintenance therapy during these 14 sessions (5 mg/kg/day via s.c. osmotic minipump). We then assessed responding for cocaine under a progressive ratio schedule, responding under extinction and cocaine-primed reinstatement of drug seeking. We also assessed the ability of cocaine to inhibit dopamine uptake in the nucleus accumbens core using fast scan cyclic voltammetry ex vivo. IntA cocaine self-administration produced psychomotor (locomotor) sensitization, strong motivation to take and seek cocaine, and it increased cocaine’s potency at the DAT. D-amphetamine co-administration suppressed the psychomotor sensitization produced by IntA cocaine experience. After cessation of D-amphetamine treatment, the motivation to take and seek cocaine was also reduced, and sensitization of cocaine’s actions at the DAT was reversed. Thus, treatment with D-amphetamine might reduce cocaine use by preventing sensitization-related changes in cocaine potency at the DAT, consistent with an incentive-sensitization view of addiction.Subject terms: Diagnostic markers, Reward, Behavioural methods, Addiction, Predictive markers     

Structural polymorphism of glycophorins demonstrated by immunoblotting techniques

We have explored the polymorphism of the glycophorin system in the human erythrocyte membrane using the immunoblotting techniques and examining 52 individuals selected without prior bias as to their serologic state and ten documented serologic variants of M, N, S, s blood group system. Polyclonal antisera to alpha glycophorin and to alpha glycophorin CNBr carboxyl terminal fragment C (residues 82-131) and M and N specific monoclonal antibodies (MoAbs) were used. The first two reagents detect specific regions of the alpha glycophorin molecule and all electrophoretically resolved species of glycophorins immunologically related to alpha and delta glycophorins (delta glycophorin, [alpha-delta] hybrids and other glycophorins with an alteration in the carboxyl terminal segment); the M and N MoAbs identified the glycophorin species containing or lacking the M or N determinant in the amino terminal octapeptide structures. We find that immunoblotting confirmed in all cases the serologically determined phenotype; we also find that polymorphic forms of the glycophorin system are relatively infrequent; immunoblotting, independent from serologic testing, was capable of detecting five mutants, two most likely S-s-U-phenotypes; a new glycophorin species was detected in normal red cells with both antiglycophorin and antipeptide C sera, which is not evident with MoAbs; immunoblots of known glycophorin variants (En(a-), U-, Mg, Mi I, II, III, V, and Sta) confirmed but also extended our knowledge of the abnormal glycophorins involved; and the He+ and Wrb(-) cells showed normal patterns.     

Seasonal cyclicity of secretogranin-II expression and its modulation by sex steroids and GnRH in the female goldfish pituitary

The secretory vesicle protein secretogranin-II (SgII), a precursor for the bioactive peptide secretoneurin, is expressed at all levels of the goldfish reproductive axis, including the hypothalamus, pituitary and ovaries. These findings led us to hypothesize that SgII is involved in reproduction and is physiologically regulated. We investigated the effects of different sex steroids on pituitary SgII expression throughout the seasonal reproductive cycle of the female goldfish, as well as the effects of GnRH and testosterone on pituitary LHbeta subunit, GH, and SgII expression in sexually recrudescent female fish using northern blot analysis. We demonstrated that SgII expression levels vary seasonally, with levels being highest in winter and lowest in spring. Sex steroids did not alter SgII expression at any of the time periods studied. In sexually mature goldfish, injection of a GnRH agonist stimulated the expression of LHbeta and SgII specifically in the pars distalis but not the neurointermediate lobe of the pituitary. Although testosterone alone did not alter the expression of either of these genes, it did abolish the stimulatory effects of GnRH on both LHbeta and SgII expression. This represents the first study where testosterone is shown to modulate SgII expression in the pituitary.