Floating treatment wetlands for domestic wastewater treatment.

Floating islands are a form of treatment wetland characterized by a mat of synthetic matrix at the water surface into which macrophytes can be planted and through which water passes. We evaluated two matrix materials for treating domestic wastewater, recycled plastic and recycled carpet fibers, for chemical oxygen demand (COD) and nitrogen removal. These materials were compared to pea gravel or open water (control). Experiments were conducted in laboratory scale columns fed with synthetic wastewater containing COD, organic and inorganic nitrogen, and mineral salts. Columns were unplanted, naturally inoculated, and operated in batch mode with continuous recirculation and aeration. COD was efficiently removed in all systems examined (>90% removal). Ammonia was efficiently removed by nitrification. Removal of total dissolved N was ∼50% by day 28, by which time most remaining nitrogen was present as NO(3)-N. Complete removal of NO(3)-N by denitrification was accomplished by dosing columns with molasses. Microbial communities of interest were visualized with denaturing gradient gel electrophoresis (DGGE) by targeting specific functional genes. Shifts in the denitrifying community were observed post-molasses addition, when nitrate levels decreased. The conditioning time for reliable nitrification was determined to be approximately three months. These results suggest that floating treatment wetlands are a viable alternative for domestic wastewater treatment.

Comparison of matched unrelated and matched related donor myeloablative hematopoietic cell transplantation for adults with acute myeloid leukemia in first remission.

Hematopoietic cell transplantation (HCT) from a matched related donor (MRD) benefits many adults with acute myeloid leukemia (AML) in first complete remission (CR1). The majority of patients does not have such a donor and will require an alternative donor if HCT is to be undertaken. We retrospectively analyzed 226 adult AML CR1 patients undergoing myeloablative unrelated donor (URD) (10/10 match, n=62; 9/10, n=29) or MRD (n=135) HCT from 1996 to 2007. The 5-year estimates of overall survival, relapse and nonrelapse mortality (NRM) were 57.9, 29.7 and 16.0%, respectively. Failure for each of these outcomes was slightly higher for 10/10 URD than MRD HCT, although statistical significance was not reached for any end point. The adjusted hazard ratios (HRs) were 1.43 (0.89-2.30, P=0.14) for overall mortality, 1.17 (0.66-2.08, P=0.60) for relapse and 1.79 (0.86-3.74, P=0.12) for NRM, respectively, and the adjusted odds ratio for grades 2-4 acute graft-versus-host disease was 1.50 (0.70-3.24, P=0.30). Overall mortality among 9/10 and 10/10 URD recipients was similar (adjusted HR 1.16 (0.52-2.61), P=0.71). These data indicate that URD HCT can provide long-term survival for CR1 AML; outcomes for 10/10 URD HCT, and possibly 9/10 URD HCT, suggest that this modality should be considered in the absence of a suitable MRD.

Senior dental students' career intentions, work-life balance and retirement plans.

OBJECTIVE: To gather information from senior dental students about their future career plans, with particular emphasis on work-life balance issues, their attitudes towards the NHS and retirement plans. METHOD: Senior dental students at the Universities of Dundee and Manchester were asked to complete a voluntary anonymous questionnaire. RESULTS: In all 141 questionnaires were completed, 42 by students in Manchester and 114 in Dundee. On qualification nearly all surveyed intend to work full time but after five years one quarter (26%) of females intend to work part time. This is significantly (p < 0.05) different from males where nearly all (98%) intend to work full time. Although the majority (65%) intend to work in general practice significant numbers (19%) wish to have a career in hospital dentistry and very few (3%) in community dentistry. Senior students seem to show no more commitment to the NHS than those in our previous study of dental school applicants. Only 3% intend to work exclusively for the NHS and 18% intend to work exclusively in the private sector. Surprising numbers had plans to retire or go part time before 60 years of age. Only 20% of the sample intended to continue working full time after the age of 60 years. The mode age that those surveyed intended to start a family was 30 years and a large majority of both sexes thought this would interrupt their professional life. More than half of the sample intend to take time out of dentistry until their children attended primary school (female 63%, male 38%) and 6% (female 6%, male 8%) until secondary school. CONCLUSIONS: Many of our findings suggest that future generations of dentists may have a pattern of professional life that will have the effect of reducing their clinical commitment, although it is not possible to determine how significant an effect this will have on the workforce. It may, however, be appropriate to take career intention into account when workforce planning.

A survey of dental school applicants' career intentions and the balance with family life.

PURPOSE: To investigate the career plans of prospective dental students and how they foresee their work life balance. METHOD: Applicants to Dundee and Manchester dental schools completed anonymous questionnaires when they attended for interview. RESULTS: The useable response rate was 94% (n=436). The majority of the respondents (91.3%) intended working full time when they enter the workforce, with no significant variation detected between males and females. The cohort anticipated their mean salary to be just over 28,000 UK pounds, five years into their career, although the males felt they would be earning 5,000 UK pounds more than the females. Individuals of Pakistani and Indian origin thought they would earn most, and Asians least. Sixty-five per cent would enter general dental practice and, of these, only 2.8% expected to work exclusively within the NHS. Fifteen per cent intended to go into the hospital dental service, with orthodontics the most popular choice of subspecialty (43.7%), followed by oral surgery (31.1%). Significant variation was seen between ethnic groups, with the hospital and community dental services being more popular with those who identified themselves as of non-white ethnic origin, although the majority would still plan on entering general dental practice. Almost half (44.5%) would take time out of their career to concentrate on childcare when children were of pre-school age, with a further 11% taking longer. Ninety per cent of females and 70% of males anticipated taking time out, of a varying duration. Half of the respondents indicated that they felt a child would affect their career to a moderate extent. CONCLUSIONS: The dental profession will be severely affected if both males and females take time out of their careers in the future. As well as a work force shortage, the problems of accessibility to NHS dental services will be exacerbated if fewer dentists choose to provide NHS care.

The future of the profession--a survey of dental school applicants.

PURPOSE: To gather background information about applicants to the dental undergraduate course, and ascertain the factors involved in their decision to study dentistry. METHOD: Applicants attending for interview at Dundee and Manchester Dental Schools completed anonymous questionnaires. The useable response rate was 94% (n = 436). RESULTS: There were equal numbers of male and female applicants to the two schools as a whole. Although there was a much broader ethnic mix in the applicants to Manchester, the overall proportion of minority ethnic groups was considerably greater than in the UK population as a whole. Seventy-five per cent came from professional backgrounds, although marked differences were apparent between ethnic groups. A quarter had family relations who were dentists, and 30% were related to doctors. Over half (53%) decided to apply within the last year, with popular motivating factors including a general interest in dentistry, a desire to help people and to work with their hands. Dentistry was the first choice of career of 89%, with medicine the most popular alternative. CONCLUSION: Valuable information was gathered from these prospective dental students regarding their backgrounds and the decision process involved in their career selection. This will prove beneficial when developing the recruitment process and allow appropriate tailoring to the target audience.

Murine marrow cellularity and the concept of stem cell competition: geographic and quantitative determinants in stem cell biology.

In unperturbed mice, the marrow cell numbers correlate with the stem cell numbers. High levels of long-term marrow engraftment are obtained with infusion of high levels of marrow cells in untreated mice. To address the issue of stem cell competition vs 'opening space', knowledge of total murine marrow cellularity and distribution of stem and progenitor cells are necessary. We determined these parameters in different mouse strains. Total cellularity in BALB/c mice was 530+/-20 million cells; stable from 8 weeks to 1 year of age. C57BL/6J mice had 466+/-48 million marrow cells. Using these data, theoretical models of infused marrow (40 million cells) replacing or adding to host marrow give chimerism values of 7.5 and 7.0%, respectively; the observed 8-week engraftment of 40 million male BALB/c marrow cells into female hosts (72 mice) gave a value of 6.91+/-0.4%. This indicates that syngeneic engraftment is determined by stem cell competition. Our studies demonstrate that most marrow cells, progenitors and engraftable stem cells are in the spine. There was increased concentration of progenitors in the spine. Total marrow harvest for stem cell purification and other experimental purposes was both mouse and cost efficient with over a four-fold decrease in animal use and a financial saving.

Low molecular weight heparin for the treatment of venous thromboembolism in pregnancy: a case series.

OBJECTIVES: To assess the use of low molecular weight heparin for the treatment of venous thromboembolism in pregnancy. DESIGN: A prospective observational study. SETTING: The maternity units in two university teaching hospitals and one district general teaching hospital. POPULATION: Thirty-six consecutive women presenting with objectively diagnosed venous thromboembolism during pregnancy and the immediate puerperium. METHODS: Treatment with the low molecular weight heparin enoxaparin, approximately 1 mg/kg s.c., twice daily, based on early pregnancy weight. MAIN OUTCOME MEASURES: Peak anti-Xa activity (three hours post-injection), alterations in treatment, side effects and the use of regional anaesthesia. RESULTS: In 33 women, the initial dose of enoxaparin provided satisfactory peak anti-Xa activity (median 0.8 u/mL, range 0.44-1.0 u/mL) and was continued. Three women required dose reduction since peak anti-Xa activities were above the therapeutic range (1.2, 1.2 and 1.1 u/mL). No woman developed thrombocytopaenia, haemorrhagic complication or further thromboembolic episode. Two women developed allergic skin reactions on enoxaparin and were changed to tinzaparin. Fifteen women had regional anaesthesia for delivery, with a reduced dose of enoxaparin (40 mg once daily), all without complication. CONCLUSIONS: Enoxaparin is a safe and effective treatment for venous thromboembolism during pregnancy and confers a major advantage over unfractionated heparin through its simplified regimen of administration.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) priming with successive concomitant low-dose Ara-C for elderly patients with secondary/refractory acute myeloid leukemia or advanced myelodysplastic syndrome.

Patients with advanced MDS and secondary AML respond poorly to chemotherapy. Granulocyte-macrophage colony-stimulating factor (GM-CSF) can stimulate proliferation of leukemic blasts and sensitize these cells to the cytotoxic effects of S-phase-specific drugs. This is the first report of safety and efficacy of GM-CSF prior to and during cytarabine in a low-dose, intermittent regimen for elderly patients with poor risk acute myelogenous leukemia or myelodysplastic syndrome. Twenty patients, age 68 to 86 years, each received 250 microg/m2 of GM-CSF (Sargramostatin; Immunex, Seattle, WA, USA) subcutaneously (s.c.) or intravenously (i.v.) for 3 days followed by GM-CSF at the same dose and cytarabine 100 mg/m2 i.v. for 3 days. GM-CSF and cytarabine were both administered for 3 days during weeks 2 and 3 followed by a 3-week rest period. Rates of CR and PR were 20% and 40%, respectively. These included clinically significant resolution of cytopenias and transfusion requirements. Many of the responding patients had been heavily pretreated prior to enrollment. One- and 2-year survival estimates are 44% and 19%, respectively. Myelosuppression was the most significant toxicity. Our findings suggest that this novel combination of GM-CSF with sequential and concomitant low-dose cytarabine can benefit patients with poor risk myeloid malignancies.

Host marrow stem cell potential and engraftability at varying times after low-dose whole-body irradiation.

High levels of chimerism in syngeneic BALB/c transplants were reported when hosts were exposed to 1 Gy (100 cGy) whole body irradiation (WBI) and infused with 40 x 10(6) marrow cells. The recovery of host stem cells and alterations of enhanced host engraftability at varying times after 1 Gy WBI have now been evaluated in this study. Male BALB/c marrow (40 x 10(6) cells) was infused into female BALB/c hosts immediately or at 6, 12, and 24 weeks after 1 Gy WBI of host female BALB/c mice; engraftment percentages 8 weeks after cell injection at week 0, 6, 12, or 24 were 68% +/- 12%, 45% +/- 15%, 51% +/- 12%, or 20% +/- 8%, respectively. Eight-week engraftment levels in nonirradiated hosts average 7.7%. Conversely, engraftable stem cells measured at 8 weeks postengraftment in 1 Gy--exposed hosts were reduced to 8.6% +/- 3% of nonirradiated mice at time 0, 35% +/- 12% 6 weeks later, 49% +/- 10% at 3 months, and 21% +/- 7% at 6 months. Engraftment was still increased and stem cell decreased 1 year after 1 Gy. Furthermore, the primary cells transplanted into 1 Gy hosts can be serially transplanted, and the predominant effect of 1 Gy is directly on engrafting stem cells and not through accessory cells. These data show that transplantation in 1 Gy mice may be delayed until recovery of hematopoiesis, suggesting strategies in allogeneic transplantation to avoid the adverse effects of cytokine storm. The incomplete recovery of engraftable stem cells out to 12 months indicates that stem cell expansion, especially in patients previously treated with radiomimetic drugs, may not be feasible. (Blood. 2001;98:1246-1251)

Epidemiology, evolution, and future of the HIV/AIDS pandemic.

We used mathematical models to address several questions concerning the epidemiologic and evolutionary future of HIV/AIDS in human populations. Our analysis suggests that 1) when HIV first enters a human population, and for many subsequent years, the epidemic is driven by early transmissions, possibly occurring before donors have seroconverted to HIV-positive status; 2) new HIV infections in a subpopulation (risk group) may decline or level off due to the saturation of the susceptible hosts rather than to evolution of the virus or to the efficacy of intervention, education, and public health measures; 3) evolution in humans for resistance to HIV infection or for the infection to engender a lower death rate will require thousands of years and will be achieved only after vast numbers of persons die of AIDS; 4) evolution is unlikely to increase the virulence of HIV; and 5) if HIV chemotherapy reduces the transmissibility of the virus, treating individual patients can reduce the frequency of HIV infections and AIDS deaths in the general population.

Stem cell engraftment strategies.

The donor stem cell phenotype and host microenvironment determine the outcome of a stem cell transplant. In a series of transplant studies in syngeneic male to female or congenic Ly5.1/Ly5.2 models in which hosts have received no or minimal irradiation (100 cGy), evidence overwhelmingly supports the concept that syngeneic engraftment is determined by stem cell competition. These approaches can be extended to H-2 mismatched allogeneic mouse combination when antigen pre-exposure and CD40-CD40 ligand antibody blockage are employed. A human trial in patients with resistant neoplasia infusing pheresed blood with 10(8) CD3 cells/kg showed that tumor responses and complete chimerism occur with very low levels of CD34+ cells/kg and that the extent of previous treatment is a critical factor in determining chimerism. A major feature of transplants is the phenotype of the donor stem cell. This phenotype shows dramatic reversible plasticity involving differentiation, adhesion protein expression, and engraftment with cytokine-induced cell-cycle transit. Homing is probably also plastic. Marked fluctuations in engraftment capacity are also seen at different points in marrow circadian rhythm.

Variables to predict engraftment of umbilical cord blood into immunodeficient mice: usefulness of the non-obese diabetic--severe combined immunodeficient assay.

Umbilical cord blood is an alternative stem cell source for patients without matched family donors. In this study, we examined several parameters that have not been studied in detail -- radiation dose, cell dose, age of mice, and maternal and neonatal characteristics of the cord blood donor -- that affect engraftment of cord blood in non-obese diabetic-severe combined immunodeficient (NOD--scid) mice. Engraftment, measured using flow cytometry analyses of human CD45(+) cells, was highest in 400 cGy-treated mice. Successful engraftment was demonstrated up to 6 months, with a mean engraftment of 31% (range 0--67%) of human cells in recipient bone marrow. Engraftment was skewed to B lymphocytes. The radiation dose of 350 cGy resulted in superior survival of the murine recipients compared with 400 cGy (P = 0.03). The sex of the NOD--scid recipients had a significant effect on survival (female superior to male, P = 0.01), but not on engraftment. There were high levels of variability among different cord units and among animals injected with the same cord unit. This variability may limit the clinical usefulness of the NOD--scid mice as hosts for the quantification of human stem cells.

Bigger is better: maternal and neonatal predictors of hematopoietic potential of umbilical cord blood units.

Umbilical cord blood (CB) is a useful stem cell source for patients without matched family donors. CB banking is expensive, however, because only a small percentage of the cord units stored are used for transplantation. In this study, we determined whether maternal factors, such as race, age, and smoking status have an effect on laboratory parameters of hematopoietic potential, such as viability, cell counts, CD34+ cell counts, and CFU-GM. We studied the effect of neonatal characteristics such as birth order, birth weight, gestational age, and sex of the baby on the same laboratory parameters. Race and maternal age had no effect on these laboratory parameters. In multivariate analysis, babies of longer gestational age had higher cell counts, but lower CD34+ cell counts and CFU-GM. Bigger babies had higher cell counts, more CD34+ cells, and more CFU-GM. Women with fewer previous live births also produced cord units with higher cell counts, CFU-GM, and CD34+ cell counts. Specifically, each 500 g increase in birth weight contributed to a 28% increase in CD34+ cell counts, each week of gestation contributed to a 9% decrease in CD34+cell counts, and each previous birth contributed to a 17% decrease in CD34+ cell counts (all P < 0.05). These data may be used to select the optimal cord blood donors and allow CB banks efficient resource allocation.

Manipulation of the stem cell as a target for hematologic malignancies.

Hematologic malignancies affect more than 80,000 patients in the United States each year. Some patients with lymphoma and leukemia are cured with conventional chemotherapy treatments. For others, autologous or allogeneic bone marrow transplantation may be the best therapeutic option. This chapter will explore novel therapies for the hematologic malignancies, using the stem cell as a target. We review work in the murine model looking at (1) the phenotype of the engrafting cells, (2) stem cell competition and host stem cells, (3) allochimerism with low-dose total body irradiation, and (4) the tolerance approach with costimulator blockade. Human data, including stem cell migration, adhesion receptor expression, and manipulations for gene therapy, are reviewed. The NOD/scid mouse model serves as a bridge between the basic bench work and human clinical trials, and we discuss applications related to umbilical cord blood and gene therapy, as well as discuss the inherent variability of this system. Finally, we address unique clinical applications in gene therapy, high-dose cell transplants, minimal myeloablation, and cellular immune therapy as approaches to treatment of for patients with hematologic malignancies.

Successful autologous bone marrow transplant without the use of blood product support.

We describe a successful autologous bone marrow transplant without the use of any blood products. The patient had relapsed large cell lymphoma. He was a Jehovah's Witness and would not accept transfusions of red blood cells or platelets. He enrolled in our Bloodless Medicine and Surgery Program and was maintained on a regimen of erythropoietin, iron, Amicar, and G-CSF throughout the transplant. He tolerated the transplant well and is alive with no evidence of disease 10 months after autografting.

Effect of ex vivo cytokine treatment on human cord blood engraftment in NOD-scid mice.

Umbilical cord blood transplantation is considered an alternative to traditional bone marrow transplantation for patients who do not have matched sibling donors. In this study, we examined the effects of ex vivo treatment of human cord blood cells with cytokine mixtures and assessed the ability of treated cells to engraft in NOD-scid mice. We incubated the cord blood with a four-factor cytokine mixture of interleukin (IL)-3, IL-6, IL-11 and stem cell factor, or with a two-factor cytokine mixture of thrombopoietin and flt-3. Incubation of cord blood for 48 h with either cytokine mixture did not affect progenitor cell number or proliferative potential as measured by the high proliferative potential (HPP) assay. Cytokine-treated cord blood injected into irradiated NOD-scid mice resulted in multilineage human engraftment. Overall, incubation with cytokines resulted in variable levels of engraftment with different cord blood samples. Incubation of cord blood with the four-factor cytokine mixture resulted in increased survival of irradiated NOD-scid recipients. These results demonstrate that short-term ex vivo treatment of human progenitor cells gives variable results on in vivo multipotential capabilities.

High-dose chemotherapy for high-risk primary breast cancer: an on-site review of the Bezwoda study.

BACKGROUND: The efficacy of high-dose chemotherapy with progenitor-cell rescue for women with breast cancer is a controversial issue. Although historically controlled trials have suggested a survival advantage for high-dose chemotherapy, several randomised studies have yet to confirm this advantage. Two studies, however, by Bezwoda, of patients with high-risk and metastatic disease, seemed to show a significant survival advantage for high-dose compared with conventional-dose chemotherapy for metastatic and high-risk primary breast cancer. METHODS: To corroborate the study results before starting a large international confirmatory study, a US team did an on-site review of records for patients in the high-risk study. Limited numbers of records were made available for review, all of which were for patients who received the high-dose-chemotherapy regimen. FINDINGS: There was much disparity between the reviewed records and the data presented at two international meetings. In addition, the reviewers saw no signed informed consent, and the institutional review committee had no record of approval for the investigational therapy. After the site visit, Bezwoda admitted scientific misconduct by using a different control chemotherapy regimen from that described in presented data. INTERPRETATION: The Bezwoda study should not be used as the basis for further trials to test the efficacy of the cyclophosphamide, mitoxantrone, etoposide regimen for high-dose chemotherapy in women with high-risk primary breast cancer. This review validates the essential nature of on-site audits, especially in single-institution studies.

Women and the world of dentistry.

It was only in 1895 that the first woman dentist in the UK graduated from Edinburgh Dental School, and a further 17 years until a women was granted a dental qualification from The Royal College of Surgeons of England. At around this time cartoons began to appear, flippantly depicting women to be working in a profession regarded by many as masculine. Over the following years women dentists became more accepted, although as recently as the 1960's women were encouraged to enter certain branches of the profession where it was thought that they would be most useful. Government publications of this era encouraged women dentists to join the Maternity and Child Welfare Service and the School Health Service. It was felt that this work would be particularly suitable for them and that child patients would react more favourably to women dentists.