Effects of interleukin-11 on the proliferation and cell cycle status of myeloid leukemic cells

Interleukin-11 (IL-11) is a pleiotropic cytokine with effects on many different targets. Within the hematopoietic system, the effects of IL- 11 are largely manifest only through combination with other cytokines, including IL-3 and Steel factor (SF). In the present study, we addressed the question of IL-11 responsiveness within the different types of human leukemic cells, as well as the mechanism of action of IL- 11 at the cellular level. Analysis of a panel of samples from different patients with acute myeloblastic leukemia (AML) and myeloid leukemic cell lines indicated that IL-11 alone was ineffective in supporting myeloid leukemic cell growth but frequently enhanced growth supported by IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), or SF. In contrast, three acute pre-B lymphocytic leukemia (pre-B-ALL) and two acute T lymphocytic leukemia (T-ALL) lines failed to respond to IL- 11 alone or when combined with other cytokines. The growth enhancement of IL-11 among the AML patient samples was dose dependent and remarkably constant with half-efficient concentrations in the range of 0.3 to 0.4 ng/mL. The thymidine suicide studies with the patient samples revealed that 40% to 50% of the blast cells were in S-phase when exposed for 16 hours to IL-3 and this level was increased to 70% to 90% in response to either IL-11 or IL-6. Our data suggest that the latter two interleukins act synergistically with the direct mitogenic factor, IL-3, in triggering AML blast-cell proliferation. Detailed analysis with several patient samples further revealed that SF and IL- 11 both enhance IL-3-supported clonogenic growth of AML blasts and the combination of all three growth factors yields optimal growth. In contrast, IL-6 does not further enhance the effect of IL-11. These results indicate that SF and IL-11 enhance IL-3-dependent clonogenic growth through two distinct pathways, whereas IL-6 and IL-11 may trigger the same pathway.     

Vascular dysfunction induced by AGE is mediated by VEGF via mechanisms involving reactive oxygen species, guanylate cyclase, and protein kinase C

OBJECTIVE: These experiments were designed to elucidate mechanisms mediating vascular dysfunction induced by advanced glycation end products (AGEs). METHODS: Skin chambers were mounted on the backs of Sprague-Dawley rats and 1 week later, granulation tissue that formed in the bottom of the chamber was exposed twice daily for 7 days to glycated rat serum albumin in the presence and absence of inhibitors of reactive oxygen intermediates, nitric oxide synthase and guanylate cyclase, protein kinase C (PKC), and a neutralizing vascular endothelial growth factor (VEGF) antibody. Vascular (125)I-albumin clearance and blood flow were quantified by use of a double isotope-dilution technique and radiolabeled microspheres, respectively. RESULTS: Albumin permeation and blood flow were increased dose-dependently to a maximum of 2 to 3 times controls by increasing the extent of glucose modification, the concentration, or the duration of exposure to glycated albumin. These increases were significantly attenuated by probucol and superoxide dismutase; N(G)-nitro-L-arginine-methyl ester (L-NAME), a nitric oxide synthase inhibitor; LY83583, a guanylate cyclase inhibitor; and LY333531, a beta-isoform-selective protein kinase C inhibitor. A neutralizing VEGF monoclonal antibody also markedly attenuated the permeability and blood flow increases induced by glycated albumin. CONCLUSIONS: These observations indicate potentially important roles for oxygen free-radicals and nitric oxide in mediating permeability and blood flow changes induced by glycated proteins via mechanisms involving increased protein kinase C activity and VEGF production. Striking similarities in the mechanism by which hyperglycemia and glycated proteins induce vascular dysfunction suggest that a common pathway mediates effects of these different metabolic imbalances on vascular dysfunction.     

Amplification of genes encoding human myeloid membrane antigens after DNA-mediated gene transfer

Spontaneous amplification of genes encoding two different human myeloid surface antigens was observed after DNA-mediated gene transfer of cellular DNA from the human myeloid cell line HL-60 into NIH-3T3 mouse fibroblasts. Transformed recipient cells with highly amplified expression of either of two donor membrane polypeptides, gp150 or p67, were isolated with a fluorescence-activated cell sorter (FACS), using monoclonal antibodies specific for human myeloid cells. Immunoprecipitation of enzymatically radioiodinated polypeptides from the surface of transformed NIH-3T3 cells confirmed that expression of these proteins was amplified tenfold to 20-fold in comparison to their expression on human myeloid cell lines. The cellular DNA of cloned secondary and tertiary transformants expressing high levels of gp150 and p67 contained amplified sets of DNA restriction fragments that hybridized with human repetitive DNA sequences. Cytogenetic analysis of subclones overexpressing gp150 revealed extrachromosomal double minutes (DMs), whose presence correlated with the unstable expression of the membrane polypeptide. Human sequences in gp150-positive clones did not localize to chromosomes, consistent with their association with extrachromosomal DMs. By contrast, p67-positive subclones stably expressed the antigen, and in situ hybridization to metaphase spreads demonstrated that amplified human DNA sequences were integrated into a specific marker chromosome. Cytogenetic analysis of the parental NIH- 3T3 subclone used in these studies disclosed DMs in a low percentage of metaphases, suggesting that the recipient cells have a propensity for amplifying donor DNA.     

Establishing and managing a periodontal biobank for research: the sharing of experience

Periodontal bio‐repositories, which allow banking of clinically validated human data and biological samples, provide an opportunity to derive biomarkers for periodontal diagnosis, prognosis and therapeutic activities which are expected to improve patient management. This article presents the establishing of the Malaysian Periodontal Database and Biobank System (MPDBS) which was initiated in 2011 with the aim to facilitate periodontal research. Partnerships were established with collaborating centres. Policies on specimen access, authorship and acknowledgement policies were agreed upon by all participating centres before the initiation of the periodontal biobank. Ethical approval for the collection of samples and data were obtained from institutional ethics review boards. A broad‐based approach for informed consent was used, which covered areas related to quality of life impacts, genetics and molecular aspects of periodontal disease. Sample collection and processing was performed using a standardized protocol. Biobanking resources such as equipment and freezers were shared with the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). In the development of the MPDBS, challenges that were previously faced by the MOCDTBS were considered. Future challenges in terms of ethical and legal issues will be faced when international collaborations necessitate the transportation of specimens across borders.     

Mandatory Procedures and Fairness in Mental Impairment Hearings

Uncertainty has attended procedures for adjudging unfitness to stand trial in Victoria pursuant to the Crimes (Mental Impairment and Unfitness to be Tried) Act 1997 (Vic) and how “special hearings” should be conducted when a person is determined to be unfit to stand trial but does not wish to pursue the defence of not guilty because of mental impairment. In R v Langley [2008] VSCA 81, (2009) 19 VR 90 the Victorian Court of Appeal clarified the procedures to be employed at jury trials on such matters and quashed a decision not in conformity with proper procedures, making clear that denial of fairness to such accused persons has the potential to result in appealable error.     

Human Rights and Review of the Involuntary Status of Patients with a Mental Illness: Kracke after Momcilovic

Arguably, Australia's most significant judicial pronouncement on the human rights of those with mental illnesses was made in 2009 by Justice Bell, the then President of the Victorian Civil and Administrative Tribunal (“VCAT”). The decision is an exhaustive analysis of the application of the Charter of Human Rights and Responsibilities Act 2006 (Vic) to the involuntary status of a person subject to a community treatment order in Victoria. It occurred in the context of delays in the conduct of reviews of the status of a mentally ill person by Victoria's Mental Health Review Board (“the Board”). The outcome of the hearing was a declaration that the Board had breached the person's human rights to a fair hearing, even though the person's involuntary status on a community treatment order was not disturbed by VCAT. Whilst some important aspects of Justice Bell's decision concerning the general methodology to be applied when analysing human rights were overturned in the subsequent Court of Appeal decision of R v Momcilovic [2010] VSCA 50, the latter decision did not concern mental health and so leaves Kracke as the most detailed articulation and analysis of human rights within this difficult sphere.     

Sexual Surrogate Partner Therapy: Legal and Ethical Issues

The Ben Lewin film The Sessions has drawn attention again to the potential role for sexual surrogate partners and sex workers in enabling persons with disabilities and impairments to give expression to their sexual needs and desires. However, away from the big screen, the ethics of registered health practitioners in themselves engaging in such therapies are highly problematic. Difficult too is the role of such practitioners in being ‘the therapist’ responsible for enabling or brokering sexual contact between their patients and those offering such services for financial reward. In some jurisdictions, arrangements involving sexual surrogate therapy (especially where the therapist benefits from it financially) may not be lawful. Further, in spite of many assertions one way and the other, there are no data enabling evaluation of the success rates of the interventions of sexual surrogates or sex workers. Whether positive outcomes to such interactions are likely in most circumstances, given that the provision of services is predicated upon idealised attachments, is questionable. It is also unclear whether sexual surrogates’ adherence to an ethical code effectively ameliorates the potential for counter-therapeutic consequences from the commodification of intimacy, and it is far from straightforward to identify what steps should be taken by the referring health practitioner to select a suitable provider of sexual services to their patient or client, and then to monitor whether the arrangement is achieving its objectives.