Cyclosporine-induced coronary endothelial dysfunction: is tetrahydrobiopterin the solution?

BACKGROUND

Coronary endothelial dysfunction after heart transplantation is predictive of cardiac allograft vasculopathy. Immunosuppressive drugs, particularly cyclosporine may contribute to this dysfunction by a direct effect. Tetrahydrobiopterin (BH(4)) is a potent antioxidant and an essential cofactor of nitric oxide biosynthesis. The purpose of this study was to investigate whether BH(4) could reverse the endothelial dysfunction induced by cyclosporine.

METHODS

A previously described in vitro model of drug incubation in Krebs-bicarbonate solution (4 degrees C, 48 hours) of porcine epicardial coronary arteries was used. Coronary endothelial function studies were performed in organ chamber experiments after incubation with cyclosporine (10(-4) mol/L) in the presence or absence of 6-methyltetrahydropterin (MH(4) [0.1 mol/L], a BH(4) analog) to assess its effect on the cyclosporine-induced endothelial dysfunction.

RESULTS

The average doses of PGF2(alpha) required to attain 50% of the maximal contraction to KCl was significantly lower (P < .001) in the cyclosporine group (8.6 +/- 1.94 x 10(-6) mol/L) compared to the control group (24.8 +/- 5.2 x 10(-6) mol/L). Exposure to cyclosporine induced a significant decrease in endothelium-dependent relaxations to serotonin (5HT) (% E(max) [5HT]: 77% +/- 4%; P < .05). Addition of MH(4) significantly reversed this impaired response (% E(max) [5HT]: 62% +/- 4%; P < .05). No alterations of relaxation were observed with bradykinin in both groups. Endothelium-independent relaxations to sodium nitroprussiate were fully preserved.

CONCLUSIONS

These results suggest a significant protective role of BH(4) on coronary endothelial function following exposure to cyclosporine, which could reduce the incidence of endothelial dysfunction and cardiac allograft vasculopathy following cardiac transplantation.

Family caregiving in cancer pain management

The experience of cancer pain is known to greatly affect family caregivers as well as patients. There are many demands placed on caregivers of cancer patients with pain at home as a result of the shifting of care from the acute setting to the home. These complex demands significantly affect caregiver quality of life. The purpose of this study was to describe the experience of pain management from the perspective of family caregivers of patients with cancer amidst the current healthcare environment. This quasi-experimental study involved 231 family caregivers of patients with cancer pain receiving home care. Family caregivers were assessed in conjunction with a pain education program that provided patient and. family education regarding pain assessment, drug and nondrug interventions. Assessment measures used were the Quality of Life (QOL)-Family Caregiver Tool, Knowledge and Attitudes about Pain (K&A) Tool, and Caregiver Finances Tool. Study findings reveal disruption to family caregiver quality of life in the areas of physical, psychological, social, and spiritual well-being. There is also a continued need for education regarding cancer pain management. Comparison between patients and family caregivers demonstrates that pain impacts both the patient experiencing it and their caregivers.

Analysis of symptom assessment and management content in nursing textbooks

This article reports on one goal of a project designed to improve end-of-life (EOL) care in nursing education. The goal was to improve the content regarding pain and EOL care included in major textbooks used in nursing education. A descriptive study design was selected using content analysis of 50 texts selected from a potential of over 700 texts. The 50 texts included 45,683 pages. The text review was conducted using an analysis framework encompassing 9 essential areas of EOL care. The study methods included content analysis as well as quantification of the content present in the texts. The 9 areas of the analysis framework were: palliative care defined; quality of life; pain; other symptom assessment/management; communication with dying patients and families; role/needs of family caregivers in EOL care; death; issues of policy, ethics, and law; and bereavement. This article reports on the findings of the analysis related to symptom assessment/management. Nursing texts have limited content on symptom assessment and management. Increased attention to this area, a critical role of nursing, is essential to improved care for patients at EOL.

Effects of a cancer genetics education programme on clinician knowledge and practice

BACKGROUND

Many clinicians lack adequate knowledge about emerging standards of care related to genetic cancer risk assessment and the features of hereditary cancer needed to identify patients at risk.

OBJECTIVE

To determine how a clinical cancer genetics education programme for community based clinicians affected participant knowledge and changed clinical practice.

METHODS

The effects of the programme on participant knowledge and changes in clinical practice were measured through pre and post session knowledge questionnaires completed by 710 participants and practice impact surveys completed after one year by 69 out of 114 eligible annual conference participants sampled.

RESULTS

Respondents showed a 40% average increase in specific cancer genetics knowledge. Respondents to the post course survey reported that they used course information and materials to counsel and refer patients for hereditary cancer risk assessment (77%), shared course information with other clinicians (83%), and wanted additional cancer genetics education (80%).

CONCLUSIONS

There was a significant immediate gain in cancer genetics knowledge among participants in a targeted outreach programme, and subset analysis indicated a positive long term effect on clinical practice. Clinician education that incorporates evidence based content and case based learning should lead to better identification and care of individuals with increased cancer risk.

Biphasic effect of daidzein on cell growth of human colon cancer cells

Colorectal cancer is one of the most common cancers in the world, poorly responding to available chemotherapeutic agents. To investigate whether natural molecules can inhibit colon cancer progression, we investigated a principle phytoestrogen found in soybean known as daidzein, and determined its effects on the human colon cancer cell line LoVo. LoVo cells were treated with 0.1, 1, 5, 10, 50 and 100 microM daidzein for 2, 3, 4 or 5 d. The results indicated that daidzein stimulated the growth of LoVo cells at 0.1 and 1 microM whereas at higher concentrations (10, 50 and 100 microM) cell growth was inhibited in a dose-dependent manner. Treatment of daidzein at 10, 50 and 100 microM resulted in cell cycle arrest at G0/G1 phase, DNA fragmentation and increases in caspase-3 activity. There were no changes in alkaline phosphatase activity (ALP), an indicator of cell differentiation, upon treatment with daidzein when compared to controls. These results indicate that daidzein has a biphasic effect on LoVo cell growth and its tumor suppressive effect is by means of cell cycle arrest and apoptosis but not through cell differentiation.

Deficiency of somatostatin (SST) receptor type 5 (SSTR5) is associated with sexually dimorphic changes in the expression of SST and SST receptors in brain and pancreas

The actions of somatostatin (SST) are mediated through five somatostatin receptor subtypes, termed SSTR1-5. Although SSTRs commonly display an overlapping pattern of tissue distribution, subtype-selective responses have been shown to occur in the same tissue. In the present study, we have investigated the changes in SSTR subtypes at the cellular and molecular level in both the brain and the pancreatic islets of mice deficient in SSTR5 (SSTR5KO). Expression levels of insulin and glucagon were also determined in the pancreas of these mice. Semi-quantitative RT-PCR and Western blot analysis showed significant increases in the expression of SSTR2 and 3 with a corresponding reduction in SSTR4 in the brains of female SSTR5KOs, while no changes were observed in male KOs. Strikingly, SST mRNA and SST-like immunoreactivity (SST-LI) were reduced in the brain of male KO animals but not in their female counterparts. In male SSTR5KO islets, there was an increase in the number of cells immunoreactive for SSTR1-3, whereas in female islets only SSTR3 expression was increased. Pancreatic SST-LI and SST mRNA, as well as immunoreactivity for insulin were reduced in male but not in female KO mice. These data indicate that deficiency of SSTR5 leads to subtype-selective sexually dimorphic changes in the expression of both brain and pancreatic SSTRs.

Community involvement in medical practitioner recruitment and retention: reflections on experience

The provision of health services to rural and remote communities has been the source of much concern and debate in recent times. One aspect of this is the universal problem of insufficient medical practitioners in rural areas and the associated issues of recruitment and retention. Rural communities can play an important role in the recruitment and retention of health professionals, particularly in terms of aiding the integration of health professionals and their families into the community. Community 'involvement' is not community 'development' in the usual sense of that term. Community involvement is about engaging and facilitating active community participation and leadership in the process at hand. This article reflects on experience gained through working with rural and remote communities in Queensland, Australia, with the key purpose of facilitating active community involvement in the recruitment and retention of medical practitioners. This article raises and discusses a number of issues arising from these experiences, with particular focus on barriers and opportunities to community involvement, and working with other agencies. Communities and agencies that attempt to increase rural community involvement in health service planning, provision, recruitment and retention should consider the following. For communities: Involvement must be real--active participation; Expectations need to be achievable (short and long term); Outcomes should be sustainable; Resources and capacity should remain in the community. For agencies: Avoid creating unrealistic community expectations; Be aware of time and resource requirements and constraints; Be consistent, forthright and honest in all dealings with communities; Keep communities informed of pending policy changes; See the process through to whatever conclusion.

The DNA sequence and analysis of human chromosome 6

Chromosome 6 is a metacentric chromosome that constitutes about 6% of the human genome. The finished sequence comprises 166,880,988 base pairs, representing the largest chromosome sequenced so far. The entire sequence has been subjected to high-quality manual annotation, resulting in the evidence-supported identification of 1,557 genes and 633 pseudogenes. Here we report that at least 96% of the protein-coding genes have been identified, as assessed by multi-species comparative sequence analysis, and provide evidence for the presence of further, otherwise unsupported exons/genes. Among these are genes directly implicated in cancer, schizophrenia, autoimmunity and many other diseases. Chromosome 6 harbours the largest transfer RNA gene cluster in the genome; we show that this cluster co-localizes with a region of high transcriptional activity. Within the essential immune loci of the major histocompatibility complex, we find HLA-B to be the most polymorphic gene on chromosome 6 and in the human genome.

Thermal effects on atomic friction

We model friction acting on the tip of an atomic force microscope as it is dragged across a surface at nonzero temperatures. We find that stick-slip motion occurs and that the average frictional force follows (absolute value lnv)(2/3), where v is the tip velocity. This compares well to recent experimental work, permitting the quantitative extraction of all microscopic parameters. We calculate the scaled form of the average frictional force's dependence on both temperature and tip speed as well as the form of the friction-force distribution function.

Sharp interface limits of phase-field models

The use of continuum phase-field models to describe the motion of well-defined interfaces is discussed for a class of phenomena that includes order-disorder transitions, spinodal decomposition and Ostwald ripening, dendritic growth, and the solidification of eutectic alloys. The projection operator method is used to extract the "sharp-interface limit" from phase-field models which have interfaces that are diffuse on a length scale xi. In particular, phase-field equations are mapped onto sharp-interface equations in the limits xi(kappa)<<1 and xi(v)/D<<1, where kappa and v are, respectively, the interface curvature and velocity and D is the diffusion constant in the bulk. The calculations provide one general set of sharp-interface equations that incorporate the Gibbs-Thomson condition, the Allen-Cahn equation, and the Kardar-Parisi-Zhang equation.

Curved tails in polymerization-based bacterial motility

The curved actin "comet-tail" of the bacterium Listeria monocytogenes is a visually striking signature of actin polymerization-based motility. Similar actin tails are associated with Shigella flexneri, spotted-fever Rickettsiae, the Vaccinia virus, and vesicles and microspheres in related in vitro systems. We show that the torque required to produce the curvature in the tail can arise from randomly placed actin filaments pushing the bacterium or particle. We find that the curvature magnitude determines the number of actively pushing filaments, independent of viscosity and of the molecular details of force generation. The variation of the curvature with time can be used to infer the dynamics of actin filaments at the bacterial surface.