Stem and Progenitor Cell Expansionin Co-culture of Mobilized CD34~ Cells and Osteopetrotic Mouse Stroma

1 IntroductionCulture systems capable of expanding and/or maintaining hematopoietic stem cells will not only facilitate our understanding of stem cell biology, but also broaden clinical applications. Among various in vitro hematopoietic culture systems, co-cultures of marrow or CD34~ cells with an adherent stromal layer that can produce cytokines and extracellular matrix components most effectively supports long-term hematopoiesis (LTC), mimicking the bone marrow micro-environment.The OP-9 stromal cells ar...     

Effect of Whitening Agents on Dentin Bonding

Background: Several studies have shown a reduction in enamel bond strengths when the bonding procedure is carried out immediately after vital bleaching with peroxides. This reduction in bond strengths has become a concern in cosmetic dentistry with the introduction of new “in‐office” and “waiting‐room” bleaching techniques. The aim of this in vitro study was to evaluate the effect of three bleaching regimens: 35% hydrogen peroxide (HP), 35% carbamide peroxide (CP), and 10% CP, on dentin bond strengths. Materials and Methods: One hundred and twenty fresh bovine incisors were used in this study. The labial surface of each tooth was ground flat to expose dentin and was subsequently polished with 600‐grit wet silicon carbide paper. The remaining dentin thickness was monitored and kept at an average of 2 mm. The teeth were randomly assigned to four bleaching regimens (n = 30): (A) control, no bleaching treatment; (B) 35% HP for 30 minutes; (C) 35% CP for 30 minutes; and (D) 10% CP for 6 hours. For each group, half of the specimens (n = 15) were bonded with Single Bond/Z100 immediately after the bleaching treatment, whereas the other half was bonded after the specimens were stored for 1 week in artificial saliva at 37°C. The specimens were fractured in shear using an Instron machine. Results: For the groups bonded immediately after bleaching, one‐way analysis of variance (ANOVA) followed by the Duncan's post hoc test revealed a statistically significant reduction in bond strengths in a range from 71% to 76%. For the groups bonded at 1 week, one‐way ANOVA showed that group B (35% HP for 30 min) resulted in the highest bond strengths, whereas 10% CP resulted in the lowest bond strengths. Student's t‐test showed that delayed bonding resulted in a significant increase in bond strengths for groups B (35% HP) and C (35% CP); whereas the group bleached with 10% CP (group D) remained in the same range obtained for immediate bonding. Storage in artificial saliva also affected the control group, reducing its bond strengths to 53% of the original.     

Experimental animal model of refractoriness to donor platelets: the effect of plasma removal and the extent of white cell reduction on allogeneic alloimmunization

Platelet transfusion effectiveness may be limited in multiply transfused patients by the development of the refractory state. White cell (WBC)-reduction filters with variable efficiency (1-3 log10 reduction) are available and have been shown to be effective in reducing the incidence of platelet alloimmunization. However, the threshold number of WBCs below which alloimmunization would no longer occur is yet to be determined. A previously established animal model was used to examine the relative efficiency of second- and third- generation filters in reducing the frequency of refractoriness to allogeneic platelets. In this model, California Black rabbits are used as blood donors and New Zealand White rabbits as transfusion recipients. Eight weekly transfusions of either second-generation or third-generation WBC-reduced blood resulted in no difference between the two groups in mean platelet survival and rate of refractoriness to allogeneic platelets. To evaluate the possible incremental benefit of removing supernatant plasma to prevent platelet refractoriness, experiments were performed in which groups of animals were given transfusion(s) with red cell suspensions that had been WBC-reduced or both plasma-depleted and WBC-reduced. A significantly lower rate of allogeneic platelet refractoriness was seen in the rabbits that received WBC-reduced and plasma-depleted red cells than in those that received red cells that had been WBC-reduced only. These data provide evidence that the combined use of plasma depletion and WBC reduction can decrease still further the frequency of refractoriness produced by allogeneic blood transfusions.     

Social intervention against AIDS among injecting drug users

Many drug injectors continue to engage in behaviors that lead them to become infected with HIV in spite of a wide variety of public health programs. In addition, many persons have begun to inject drugs in spite of knowing the risks of AIDS. The inadequacy of current efforts to prevent these behaviors suggests that additional forms of intervention should be attempted. We suggest that social interventions be tried to complement current programs (almost all of which have an individual focus). Evidence that social factors such as peer pressure and the social relations of race affect risk behavior is presented. Social interventions that are discussed include organizing drug injectors against AIDS in ways analogous to those in which gays organized against the epidemic, and finding ways to change large-scale social relationships that predispose people to inject drugs.     

Process and predictors of drug treatment referral and referral uptake at the Sydney Medically Supervised Injecting Centre

Introduction and Aims . Low‐threshold drug services such as drug consumption rooms (DCRs) have been posited as referral gateways to drug treatment for injecting drug users (IDUs). We examined the process and predictors of drug treatment referral and referral uptake at an Australian DCR. Design and Methods . We undertook behavioural surveillance of the Sydney Medically Supervised Injecting Centre (MSIC) client cohort between May 2001 and October 2002. Data were collected for 3715 IDUs on demographics, injecting and drug use behaviours at registration and all subsequent MSIC service utilisation, including referrals. Referral uptake (defined as presentation for assessment at the relevant agency) was traced via reply‐paid postcards included with written referrals. Results . Sixteen per cent of clients who received written referrals to drug treatment had confirmed drug treatment referral uptake. Factors associated with drug treatment referral were frequent MSIC attendance [adjusted odds ratios (AOR = 9.4], receipt of written health (AOR = 4.8) or psychosocial (AOR = 4.3) referrals, heroin as main drug injected (AOR = 1.9) and completion of high school education (AOR = 1.6). Factors associated positively with drug treatment referral uptake were recent sex work (AOR = 2.6) and at least daily injection (AOR 2.3). Previous psychiatric illness or self‐harm was associated negatively with drug treatment referral uptake (AOR = 0.2). Discussion and Conclusions . MSIC engaged IDUs successfully in drug treatment referral and this was associated with presentation for drug treatment assessment and other health and psychosocial services. To improve rates of drug treatment referral and uptake, those with a history of mental health issues may require more intensive referral and case management.     

The Amino Acid Composition of Hemoglobin. V. The Preparation of Purified Hemoglobin Fractions by Chromatography on Cellulose Exchangers and Their Identification by Starch Gel Electrophoresis Using Tris-Borate-EDTA Buffer

The chromatographic separation of hemoglobin on two cellulose exchangers,CMC and DEAE, is discussed. Problems related to the use of these technicsare described. In addition, our experience with the use of Tris-Borate-EDTAbuffer (Smithies) for hemoglobin electrophoresis in starch gel is presented.

Submitted on May 4, 1964 Accepted on July 14, 1964     

Intrauterine Fetal Surgery A Nursing Challenge

Surgical treatment of the fetus In utero offers new options for selected families with fetal anomalies. Nurses caring for these families must be prepared to meet their unique needs. The diagnosis, treatment, support, and follow-up care of the family is discussed.