PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Essential elements”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59Linked to original sources

Immunoglobulin is a highly diverse self-molecule that improves cellular diversity and function during immune reconstitution.

Paradoxically, human B cell immune deficiencies are associated with increased susceptibility to viral and fungi infections, which are T cell immunity related infections. Also, some viral infections occurring in immune depressed patients such as cytomegalovirus infections are recommended to be treated with intravenous immunoglobulin (IVIg) in combination with antiviral therapy. This fact has no clear biological explanation but it has been shown to be successful. Recently, B cells and immunoglobulin were identified as essential elements driving T cell receptor (TCR) diversity generation. Idiotype peptides of B cell immunoglobulin may be the driving force for the antigen presenting function of B cells and other antigen presenting cells to influence the T cell repertoire. This seems to be another relevance of Jerne's idiotypic network and another function of immunoglobulin. Since T cells function depends on the diversity of the TCR repertoire, means to increase the diversity of the T cell repertoire may improve T cell function in situations characterized by a contracted TCR repertoire, such as AIDS, primary immunodeficiency, cancer, autoimmunity and following chemotherapy and hematopoietic precursors transplantation. The clinical hypothesis here put forward is that B cells and/or immunoglobulin may be used therapeutically aiming to increase and potentially to restore T cell repertoire diversity improving T cell function in situations implicating a contracted T cell repertoire. The fact that immunoglobulin influence the composition of T cell repertoire by increasing its diversity allows a much wider application of this molecule in the clinical practice. Here is presented a novel reasoning for the use of IVIg in humans, which should be explored. All the situations where immune reconstitution occurs are potentially a target for this therapeutically mechanism, aiming to fast and improve the diversity of the reconstituted immune repertoires. This new role of Ig molecule, an old and widely therapeutically used molecule, may help to explain several effects that IVIg have in the T cell compartment, such as modulation of the activation and function of effectors T cells. The idea that immunoglobulin is essential in the generation and maintenance of a diverse compartment of T cells, affecting T cell function via that mechanism suggests a promising approach to medical conditions involving immune reconstitution. Furthermore, it represents a new paradigm of understanding the immune system as a complex, interdependent web of cells/cell products that inter-affect each other generation, function and survival.

Animals↗

Interspecific and geographical variations of trace element concentrations in Pectinidae from European waters.

Cd, Cu and Zn were analysed in the organs and tissues of the three scallop species from the Bay of Biscay, the variegated Chlamys varia L., the queen scallop Aequipecten opercularis L. and the common scallop Pecten maximus L. for interspecific comparisons. In P. maximus the greatest concentrations of Cd and Cu were found in the digestive gland, whereas the two other species showed similar levels of Cd between digestive gland and kidneys and higher renal Cu concentrations. However, the digestive gland of all Pectinidae species contained from 75% to 93% and 52% to 74% of the total body burdens of Cd and Cu, respectively. Whatever the species, kidneys displayed the highest Zn concentrations, which therefore contained from 53% to 97% of the total body burden of this metal. Also using reported results, ratios between the concentrations in the digestive gland and that in the kidneys discriminated two groups of Pectinidae: (1) the Pecten group (P. maximus, P. jacobeus and Adamussium colbecki) with a Cd ratio > or = 4, a Cu ratio > or = 1 and a Zn ratio > 20x10(-3); (2) the Chlamys group with a Cd ratio < or = 1, a Cu ratio < or = 1 and a Zn ratio < or = 6x10(-3). However, no differences in the detoxification processes in the digestive gland were found between groups in this study. 72-80% of the total Cd was found to be soluble, probably bound to metalloproteins such as metallothioneins, while Cu and Zn were mainly found associated to the insoluble fraction of the digestive gland cells whatever the species. Queen scallops from the Faroe Islands were also considered to examine variations of the metal concentrations due to the geographical origin. In this northern area, queen scallops displayed Cd concentrations 2, 4 and 6 times higher in kidneys, muscle and digestive gland, respectively, compared to those from the Bay of Biscay. Consequently, the Cd concentrations in the whole soft parts of the queen scallops were more than 6 times higher in the Faroe Islands than in the Bay of Biscay. In contrast to Cd, both Cu and Zn concentrations in the whole soft parts were 2 times lower in the Faroe Islands, suggesting lower bioavailability of these essential elements.

Analysis of Variance↗

The UNESCO Bioethics Declaration 'social responsibility' principle and cost-effectiveness price evaluations for essential medicines.

The United Nations Scientific, Education and Cultural Organisation (UNESCO) has commenced drafting a Universal Bioethics Declaration. Some in the relevant UNESCO drafting committee have previously desired to restrict its content to general principles concerning the application (but not necessarily the goals) of science and technology. As potentially a crucial agenda-setting statement of global bioethics, however, it is arguable important the Universal Bioethics Declaration transparently address major bioethical dilemmas in the field of public health, such as universal access to affordable, essential medicines. Article 13 (Social Responsibility) of the Preliminary Draft Universal Bioethics Declaration states: 'Any decision or practice shall ensure that progress in science and technology contributes, wherever possible, to the common good, including the achievement of goals such as: (i) access to quality health care and essential medicines, including for reproductive health and health of children.' Cost effectiveness pricing systems, such as that most notably used in Australia's Pharmaceutical Benefits Scheme (PBS), arguably represent one of the most scientifically effective mechanisms whereby public monies may be utilised to assist in the provision of medicines for the common good. They contain two essential elements: first, a process of scientific evaluation of objectively demonstrated therapeutic significance, and then, a fiscal lever (the government reimbursement price) attached to that evaluation. It is now well established that the US Pharmaceutical Research and Manufacturers Association (Pharma), through the assistance of the US Trade Representative (USTR), saw the Australia United States Free Trade Agreement (AUSFTA) as an opportunity to fulfill a legislative mandate to 'eliminate' the cost-effectiveness pricing system in Australia's PBS. One of the most remarkable features of the arguments raised against the PBS in this context was the fact that they made almost no reference to the normative discourse of bioethics or international human rights. Provisions such as Article 13 in UNESCO's Universal Bioethics Declaration, although they will create no immediate obligations under international law, may play an extremely valuable role in legitimising the use of bioethical and human rights concepts in access to medicines debates surrounding multilateral and bilateral international trade deals such as the AUSFTA.

Australia↗

[ALCOHOLIC HEPATITIS]

At present, the relation between alcoholic consumption and the development of hepatic injury is clearly defined. However, the influence of genetic factors, the existence of associated pathologies, and the concomitant use of other hepatotoxic agents should also be considered.During chronic drunkenness, great quantities of oxygen free radicals are produced, redox balance is disturbed, and the defensive capacity of natural antioxidants is exceeded. All these factors originate an "oxidative stress," that totally distorts the hepatocellular function. Llkewise, an increase in the acetaldehyde intracellular concentration modifies several cellular proteins, deteriorating even more the hepatic activity. The importance of the "neo-antigens" between cellular components and acetaldehyde is still undefined, as well as their role in the formation of the Mallory Bodies.On the other hand, the complex network of intercellular and intracellular communications that includes cytokines, adherence molecules and membrane receptors are essential elements to be considered in the alcoholic liver disease genesis. The endotoxin, the TNF-a, the IL-8, as well as the ROIs production seem to be the most important factors.With reference to Alcoholic Hepatitis, the development of an exaggerated inflammatory response with the existence of neutrophiles may be the main mechanism of hepatocellular injury (82, 167, 168.)The final diagnosis of Alcoholic Hepatitis is histological. This also enables to measure the injury severity and to determine the presence of fibrosis and/or cirrhosis, in which case prognosis is more uncertain.Should a history of exaggerated alcoholic ingestion exist, diagnosis could be clinically determined. There is a great variability of clinical symptoms, and some patients present chronic liver disease complications frequently. Those who develop severe liver insufficiency will present leukocytosis, icterus and fever. In these cases, mortality can be as high as 80 per cent. There is no relationship between the alteration of liver function tests and the injury severity.The usefulness of antioxidants in cirrhosis has been demonstrated in animal modeis and in some studies made in human voluntarles. However, their role as therapy within the context of Alcoholic Hepatitis has not been yet defined.In conclusion, several therapeutic approaches have been investigated and from all of them, only steroids have proven to be effective on patients properly selected. The discriminative function (DF) benefit has been confirmed in certain studies. Should a patient have a DIF of more than 93, he/she may receive corticosterold treatment. Contral ndicati ons are a bsol ute when the patientpresents infection, renal insufficiency or gastrointestinal bleeding.Once the patient has been compensated, ABSTINENCE is essential. Likewise, an appropriate nutritional support is an important part of the treatment.Where the possibility of Liver Transplant exists, this should be planned if there is a deterioration of the patient's general condition or if he/she compiles with the necessary criteria, since the survival rate in these cases is similar to those who received a transpiant due to other causes.

Journal Article↗

Mail-order prescriptions requiring clarification contact with the prescriber: prevalence, reasons, and implications.

BACKGROUND: Prescription review by pharmacists prior to dispensing is an important step in an overall strategy for preventing medication errors. Contacts with prescribers may be required to clarify missing, unclear, or inconsistent information. While essential to reduce the likelihood of potential patient harm, clarification contacts are time-consuming for pharmacists and prescribers. The scope of the issue and the factors that contribute to it are not well understood. OBJECTIVE: To quantify the frequency of contacts with prescribers that were necessary to obtain clarification of prescriptions and to identify the factors that made these prescriber contacts necessary. METHODS: An analysis was conducted involving new prescriptions received by a national mail-order pharmacy that required clarification contacts with prescribers for quality reasons (i.e., those potentially impacting the accuracy of dispensing). Excluding refills and renewals, the percentage of new prescriptions requiring clarification contacts was calculated and categorized by incoming delivery channel (mail, fax, telephone, etc.). The quality problems that prompted these contacts were categorized according to the problem identified. RESULTS: Among the total of 295378 new prescription orders received during the 1-week study period (from April 7 to April 13, 2002), 8.7% contained quality problems that necessitated clarification contact with prescribers. Prescriptions received by fax transmission and mail were most likely to require clarification as compared with direct telephone conversation and miscellaneous (including electronic) channels. Among prescriptions that required a clarification contact for quality problems, an average of 2.4 problems per prescription was observed. The most common problems were: directions unclear or missing (24.3%); refill quantity unclear, missing, or incorrect (24.3%); dosage unclear (20.2%); drug name or strength unclear (13.2%); missing physician or patient data (11.4%); and missing prescriber signature (3.2%). CONCLUSION: Prescriber clarification contacts are frequently needed to reduce the potential for medication error in the current prescription fulfillment process. While these contacts are necessary to clarify data elements essential to accurate medication dispensing, they are time- and resource-intensive. These study results suggest that alternate prescription order channels, including electronic, could reduce the sizable burden of prescription order clarification in mail-order pharmacy.

Communication↗

Management of dietary essential metals (iron, copper, zinc, chromium and manganese) by Wistar and Zucker obese rats fed a self-selected high-energy diet.

The balances and content of essential elements (iron, copper, zinc, chromium and manganese) in the body of Wistar, Zucker lean and Zucker obese rats fed a reference or cafeteria diet from day 30 to 60 after birth have been studied. Intestinal iron absorption compensated for low iron content of the cafeteria diet and the extra needs of growth and fat deposition. It can be assumed that the altered energy regulation processes that afflict the genetically obese rat are not directly related to altered iron metabolism. Obese Zucker rats had lower copper tissue concentrations than lean rats, but when fed a cafeteria diet the differences between Zucker rats strains disappear. This cannot be traced to large differences in diet copper concentration. A low diet availability of zinc--such as that of cafeteria-fed fa/fa rats--is easily compensated for by increasing absorption. So, as a consequence, we can conclude that genetic obesity did not impair zinc absorption. There was no deficit of zinc in any of the groups studied; the rats have enough capacity to extract zinc within a wide range of dietary concentrations. The absorption of dietary chromium was inversely proportional to its concentration. The ability to extract chromium from the diet and the very low urinary losses are a consequence of its scarcity in most dietary items. Despite wide variations in the manganese of the diets, the absorption rates were practically unchanged except for obese rats fed the cafeteria diet. It seems that this low absorptive capacity is enough to supply the rat with the manganese it needs, since a sizeable--but subjected to 8-fold-span variations--proportion is lost in the urine. This alone points towards a considerable excess of manganese in both diets studied. Obesity does not have a significant effect on the abilities to absorb and retain minerals, since these processes were more related to dietary availability. Management of essential metals by obese rats depends whether this condition is genetic or induced by diet. Most of the differences observed can be related to differences in diet concentration, to the excess fat content or different metabolic attitude to use substrates of obese animals. The data presented show that the cafeteria diet used adequately serves the mineral needs of the rat, since the rat adapts its absorbing and retaining strategies to match the dietary availability of these minerals.

Animals↗

Methodologic guidelines for the design of high-dose chemotherapy regimens.

PURPOSE: The objective of this report is to review the research methods that have been used in the design, analysis, and reporting of Phase I dose-escalation studies of high-dose chemotherapy (HDCT) with bone marrow or stem cell support and to propose new guidelines for such studies that incorporate emerging principles of pharmacology, toxicity assessment, statistical design, and long-term follow-up. METHODS: We performed a search of original, English-language, peer-reviewed full-length reports of HDCT (with or without radiotherapy) and unmanipulated hematopoietic precursor support (autologous bone marrow or stem cells or allogeneic bone marrow) in which one or more drug doses were escalated to identify dose-limiting toxicities needed for the design of subsequent Phase II trials. We reviewed the design, execution, analysis, and reporting of these trials to develop a coherent set of guidelines for the initiation of new HDCT regimens. The primary elements included in our analysis were the technique of dose escalation, the choice and application of toxicity grading scale, and the pharmacologic correlates of dose escalation. We also evaluated the methods employed to define dose-limiting toxicities and to select the maximum tolerated dose and the dose recommended for further study. We then examined whether subsequent Phase II trials based on these definitions corroborated the findings from the prior Phase I studies and summarized the findings from pharmacologic analyses that were reported from a subset of these investigations. RESULTS: Thirty-five reports met the criteria for our literature review. Two standard methods of dose escalation (fixed increments or modified Fibonacci increments) were described in detail and were employed in the majority (30/35) of the studies. In 5 studies, the details of dose escalation were either not provided or not adequately referenced. There was marked heterogeneity among toxicity grading methods; scales used included the National Cancer Institute Common Toxicity Criteria (or similar scales such as the United States cooperative group or World Health Organization scales) as well as substantially modified versions of those instruments. Wide variations in the methods used to identify dose-limiting toxicities were observed. Statistical considerations, applied to the identification of the maximum tolerated or Phase II recommended dose, were similarly heterogeneous. Phase II trial designs varied from a simple expansion of the Phase I trial to separate, formally conducted studies. Nine Phase I trials featured pharmacologic analyses, and these ranged from simple pharmacokinetic evaluations to more complex analyses of the relationship between drug dose and the molecular targets of drug action. CONCLUSIONS: Phase I clinical trials in the HDCT setting have been designed, analyzed, and reported using heterogeneous methods that limited their application to Phase II and II investigations. Moreover, correlative pharmacologic analyses have not been routinely undertaken during this critical Phase I stage. We propose guidelines for the design of new Phase I studies of HDCT based on 4 essential elements: (1) rational preclinical and clinical pharmacologic foundation for the regimen and for the agent selected for dose escalation; (2) incorporation of analytical pharmacology in the design and analysis of the regimen under investigation; (3) clear, prospective definitions of the dose- or exposure-limiting toxicities that can be distinguished from modality-dependent toxicities; selection of an appropriate toxicity grading scale, including an assessment of cumulative, delayed, and long-term effects of HDCT, particularly when designing tandem or repetitive cycle regimens; and (4) statistical input into the design, execution, analysis, interpretation, and reporting of these studies.

Antineoplastic Combined Chemotherapy Protocols↗

Molecular mechanisms in uterine epithelium during trophoblast binding: the role of small GTPase RhoA in human uterine Ishikawa cells.

BACKGROUND: Embryo implantation requires that uterine epithelium develops competence to bind trophoblast to its apical (free) poles. This essential element of uterine receptivity seems to depend on a destabilisation of the apico-basal polarity of endometrial epithelium. Accordingly, a reorganisation of the actin cytoskeleton regulated by the small GTPase RhoA plays an important role in human uterine epithelial RL95-2 cells for binding of human trophoblastoid JAR cells. We now obtained new insight into trophoblast binding using human uterine epithelial Ishikawa cells. METHODS: Polarity of Ishikawa cells was investigated by electron microscopy, apical adhesiveness was tested by adhesion assay. Analyses of subcellular distribution of filamentous actin (F-actin) and RhoA in apical and basal cell poles were performed by confocal laser scanning microscopy (CLSM) with and without binding of JAR spheroids as well as with and without inhibition of small Rho GTPases by Clostridium difficile toxin A (toxin A). In the latter case, subcellular distribution of RhoA was additionally investigated by Western blotting. RESULTS: Ishikawa cells express apical adhesiveness for JAR spheroids and moderate apico-basal polarity. Without contact to JAR spheroids, significantly higher signalling intensities of F-actin and RhoA were found at the basal as compared to the apical poles in Ishikawa cells. RhoA was equally distributed between the membrane fraction and the cytosol fraction. Levels of F-actin and RhoA signals became equalised in the apical and basal regions upon contact to JAR spheroids. After inhibition of Rho GTPases, Ishikawa cells remained adhesive for JAR spheroids, the gradient of fluorescence signals of F-actin and RhoA was maintained while the amount of RhoA was reduced in the cytosolic fraction with a comparable increase in the membrane fraction. CONCLUSION: Ishikawa cells respond to JAR contact as well as to treatment with toxin A with rearrangement of F-actin and small GTPase RhoA but seem to be able to modify signalling pathways in a way not elucidated so far in endometrial cells. This ability may be linked to the degree of polar organisation observed in Ishikawa cells indicating an essential role of cell phenotype modification in apical adhesiveness of uterine epithelium for trophoblast in vivo.

Journal Article↗

An interferon-sensitive response element is involved in constitutive caspase-8 gene expression in neuroblastoma cells.

We previously identified a 1.2 Kb DNA element (P-1161/+16), 5' to caspase-8 exon-1, that acts as promoter in caspase-8-positive, but not in caspase-8-negative neuroblastoma (NB) cells. The P-1161/+16 DNA element regulates both constitutive and interferon IFN-gamma-inducible caspase-8 expression. Two GAS (IFN-activated sequence, STAT-1 binding site) and two ISRE (interferon sensitive response element, IRF binding site) were present in P-1161/+16. Deletion studies indicated that elements essential for promoter activity in NB cells were present in a 167 bp region 5' flanking exon-1 (P-151/+16), which contains an ISRE at position -32. The transcription initiation site was mapped by 5' rapid amplification of cDNA end (RACE) at position -20 from caspase-8 cDNA reference sequence. Disruption of the ISRE-32 indicated that it is required for both constitutive and IFN-gamma-inducible caspase-8 expression. IRF-1 and IRF-2 transcription factors bind to the (-151/+16) DNA fragment in vitro. Chromatin immunoprecipitation (ChIP) assays showed that IRF-1 and IRF-2 bind to the DNA region at the 5' of caspase-8 gene in NB cells, which show constitutive expression but not in caspase-8 negative cells. In these last cells, up-regulation of caspase-8 by IFN-gamma was associated to induction of IRF-1 and IRF-2 binding to caspase-8 promoter and increased histone acetylation. Moreover, RNA interference experiments also supported the involvement of IRF-1 and IRF-2 in constitutive caspase-8 expression in NB cells.

Antiviral Agents↗

Ras regulates the association of serum response factor and CCAAT/enhancer-binding protein beta.

The serum response element (SRE) is a promoter element essential for transcriptional activation of immediate early genes, such as c-fos and early growth response-1, by mitogenic signals. Several transcription factors bind the SRE, including the serum response factor (SRF), the ternary complex factor, and the CCAAT/enhancer-binding protein beta (C/EBPbeta). The C/EBPbeta mRNA encodes three translation products of 38, 35, and 20 kDa. p35-C/EBPbeta activates transcription of the SRE in an SRF-dependent fashion, whereas p20-C/EBPbeta, which initiates at an internal in-frame methionine, lacks a transactivation domain and inhibits transcription. We show that SRF and C/EBPbeta interact in vivo through the DNA binding domain of SRF and the C terminus of C/EBPbeta common to p35/38 and p20. Therefore, like the ternary complex factor, C/EBPbeta may be recruited to the SRE not only by binding to the DNA, which is not a high affinity site, but also by protein-protein interactions with SRF. Strikingly, in both the mammalian two-hybrid assay and in vivo coimmunoprecipitations, the association of SRF and p35-C/EBPbeta but not p20-C/EBPbeta is dramatically stimulated by activated Ras. Furthermore, mutation of the threonine within a mitogen-activated protein kinase consensus motif in the C terminus of C/EBPbeta eliminates the response to Ras. These results suggest a new mechanism by which mitogenic signals may influence transcription activity of the SRE by selectively promoting protein-protein interactions between SRF and the transactivator p35-C/EBPbeta.

3T3 Cells↗

The MONA LISA hypothesis in the time of leptin.

The regulation of body fat stores is a problem of energy and nutrient balance that can be most readily viewed as a feedback system. Several elements are involved in any feedback system, including afferent signals, a controller that senses the afferent signals and transduces their information and then activates efferent controls that regulate the controlled system. The recent discovery of leptin has provided a major missing link in the feedback control system. This afferent signal is produced exclusively in fat cells of nonpregnant mammals but can be produced in the placenta as well. This circulating peptide has a very strong relationship to the level of body fat and its absence experimentally and clinically produces massive obesity. In the controller, or brain, several anatomic regions play a central role in regulating fat stores. Damage to the ventromedial nucleus (VMH) or the paraventricular nucleus (PVN) in the hypothalamus produces massive obesity in mammals and birds. Injury to the central nucleus of the amygala will also produce obesity. In contrast, damage to the lateral hypothalamus reduces body fat. The syndrome of leptin deficiency or defects in the leptin receptors produce a massive obesity that is metabolically similar to the VMH or PVN lesion syndromes of obesity, suggesting that leptin may have its metabolic effects through these medial hypothalamic centers. Support for this idea has come from studies showing that damage to the PVN or VMH will block the effects of leptin. A number of neuropeptides and monoamines are involved with modulating of food intake and fat stores. Both serotonin, acting through 5-HT2C receptors, and norepinephrine, acting through beta 2 and/or beta 3 receptors, reduce food intake. A variety of peptides also influence food intake and body fat. Neuropeptide Y, dynorphin, galanin, and melanocyte-stimulating hormone all increase food intake. In contrast, a large number of peptides--including cholecystokinin, corticotrophin-releasing hormone/urocortin, enterostatin, insulin, leptin, alpha-MSH, and TRH--reduce food intake. Chronic administration of neuropeptide Y, acting through Y-5 receptors, can produce chronically increased food intake and obesity. This syndrome is similar to the VMH syndrome and suggests that NPY must be acting as an inhibitor of a feeding system. The melanocortin receptor system may be particularly important because a mouse that does not express MC4 receptors is massively overweight. These central systems modulate food intake and fat stores by the controlled system. Glucocorticoids from the adrenal gland are important in obesity, since adrenalectomy will reverse or prevent the development of all forms of obesity. The sympathetic nervous system is also important because low sympathetic activity is associated with experimental and clinical obesity. The reciprocal relationship between food intake and sympathetic activity has been a robust relationship, suggesting that beta receptors in the periphery or brain may be involved in feeding control. In one model of dietary obesity resulting when animals eat a high-fat diet, the syndrome is blocked by inhibitory adrenal steroid activity. These animals show a lower level of sympathetic activity and a low level of brain serotonin. Finally, they show an enhanced sensitivity to essential fatty acids when these are applied to the tongue or given into the gut. In this chapter, the control of energy stores as fat is viewed as a feedback system. Leptin is perceived as a key afferent signal and glucocorticoids and the sympathetic nervous system through beta receptors as essential elements of this control system.

Animals↗

Risk management frameworks for human health and environmental risks.

A comprehensive analytical review of the risk assessment, risk management, and risk communication approaches currently being undertaken by key national, provincial/state, territorial, and international agencies was conducted. The information acquired for review was used to identify the differences, commonalities, strengths, and weaknesses among the various approaches, and to identify elements that should be included in an effective, current, and comprehensive approach applicable to environmental, human health and occupational health risks. More than 80 agencies, organizations, and advisory councils, encompassing more than 100 risk documents, were examined during the period from February 2000 until November 2002. An overview was made of the most important general frameworks for risk assessment, risk management, and risk communication for human health and ecological risk, and for occupational health risk. In addition, frameworks for specific applications were reviewed and summarized, including those for (1)contaminated sites; (2) northern contaminants; (3) priority substances; (4) standards development; (5) food safety; (6) medical devices; (7) prescription drug use; (8) emergency response; (9) transportation; (10) risk communication. Twelve frameworks were selected for more extensive review on the basis of representation of the areas of human health, ecological, and occupational health risk; relevance to Canadian risk management needs; representation of comprehensive and well-defined approaches; generalizability with their risk areas; representation of "state of the art" in Canada, the United States, and/or internationally; and extent of usage of potential usage within Canada. These 12 frameworks were: 1. Framework for Environmental Health Risk Management (US Presidential/Congressional Commission on Risk Assessment and Risk Management, 1997). 2. Health Risk Determination: The Challenge of Health Protection (Health and Welfare Canada, 1990). 3. Health Canada Decision-Making Framework for Identifying, Assessing and Managing Health Risks (Health Canada, 2000). 4. Canadian Environmental Protection Act: Human Health Risk Assessment of Priority Substances(Health Canada, 1994). 5. CSA-Q8550 Risk Management: Guidelines for Decision-Makers (Canada Standards Association, 1997). 6. Risk Assessment in the Federal Government: Managing the Process (US National Research Council, 1983). 7. Understanding Risk: Informing Decisions in a Democratic Society (US National Research Council, 1996). 8. Environmental Health Risk Assessment (enHealth Council of Australia, 2002). 9. A Framework for Ecological Risk Assessment (CCME, 1996). 10. Ecological Risk Assessments of Priority Substances Under the Canadian Environmental Protection Act (Environment Canada, 1996).11. Guidelines for Ecological Risk Assessment (US EPA, 1998b). 12. Proposed Model for Occupational Health Risk Assessment and Management (Rampal & Sadhra, 1999). Based on the extensive review of these frameworks, seven key elements that should be included in a comprehensive framework for human health, ecological, and occupational risk assessment and management were identified: 1. Problem formulation stage. 2. Stakeholder involvement. 3. Communication. 4. Quantitative risk assessment components. 5. Iteration and evaluation. 6. Informed decision making. 7. Flexibility. On the basis of this overarching approach to risk management, the following "checklist" to ensure a good risk management decision is proposed: - Make sure you're solving the right problem. - Consider the problem and the risk within the full context of the situation, using a broad perspective. - Acknowledge, incorporate, and balance the multiple dimensions of risk. - Ensure the highest degree of reliability for all components of the risk management process. - Involve interested and effected parties from the outset of the process. - Commit to honest and open communication between all parties. - Employ continuous evaluation throughout the process (formative, process, and outcome evaluation), and be prepared to change the decision if new information becomes available. Comprehensive and sound principles are critical to providing structure and integrity to risk management frameworks. Guiding principles are intended to provide an ethical grounding for considering the many factors involved in risk management decision making. Ten principles are proposed to guide risk management decision making. The first four principles were adapted and modified from Hattis (1996) along with the addition of two more principles by Hrudey (2000). These have been supplemented by another four principles to make the 10 presented. The principles are based in fundamental ethical principles and values. These principles are intended to be aspirational rather than prescriptive--their application requires flexibility and practical judgement. Risk management is inherently a process in search of balance among competing interests and concerns. Each risk management decision will be "balancing act" of competing priorities, and trade-offs may sometimes have to be made between seemingly conflicting principles. The 10 decision-making principles, with the corresponding ethical principle in italics are: 1. Do more good than harm (beneficence, nonmalificence).- The ultimate goal of good risk management is to prevent or minimize risk, or to "do good" as much as possible. 2. Fair process of decision making (fairness, natural justice). - Risk management must be just, equitable, impartial, unbiased, dispassionate, and objective as far as possible given the circumstances of each situation. 3. Ensure an equitable distribution of risk (equity). - An equitable process of risk management would ensure fair outcomes and equal treatment of all concerned through an equal distribution of benefits and burdens (includes the concept of distributive justice, i.e., equal opportunities for all individuals). 4. Seek optimal use of limited risk management resources (utility). - Optimal risk management demands using limited resources where they will achieve the most risk reduction of overall benefit. 5. Promise no more risk management that can be delivered (honesty).- Unrealistic expectations of risk management can be avoided with honest and candid public accounting of what we know and don't know, and what we can and can't do using risk assessment and risk management. 6. Impose no more risk that you would tolerate yourself (the Golden Rule). - The Golden Rule is important in risk management because it forces decision makers to abandon complete detachment from their decisions so they may understand the perspectives of those affected. 7. Be cautious in the face of uncertainty ("better safe than sorry"). - Risk management must adopt a cautious approach when faced with a potentially serous risk, even if the evidence is uncertain. 8. Foster informed risk decision making for all stakeholders (autonomy). - Fostering autonomous decision making involves both providing people with the opportunity to participate, and full and honest disclosure of all the information required for informed decisions. 9. Risk management processes must be flexible and evolutionary to be open to new knowledge and understanding (evolution, evaluation, iterative process). - The incorporation of new evidence requires that risk management be a flexible, evolutionary, and iterative process, and that evaluation is employed at the beginning and througthout the process. 10. the complete elimination fo risk is not possible (life is not risk free).- Risk is pervasive in our society, and cannot be totally eliminated despite an oft-expressed public desire for "zero risk". However, the level of risk that may ve tolerable by any individual is dependent on values of beliefs, as well as scientific information. Each agency must continue to employ a process that meets the needs of their specific application of risk management. A single approach cannot satisfy the diverse areas to which risk decisions are being applied. However, with increasing experience in the application of the approaches, we are evolving to a common understanding of the essential elements and principles required for successful risk assessment, risk management, and risk communication. Risk management will continue to be a balancing act of competing priorities and needs. Flexibility and good judgement are ultimately the key to successfully making appropriate risk decisions.

Canada↗

Part-time physicians. Physician workload and patient-based assessments of primary care performance.

OBJECTIVE: To examine the relationship between the number of hours physicians work and patients' assessment of the physician. DESIGN: Cross-sectional study with physician and patient surveys. SETTING: Primary care practices in Massachusetts. PARTICIPANTS: A random sample of 6810 Massachusetts state employees in 15 different health plans. MAIN OUTCOME MEASURES: Eleven summary scales measuring 7 essential elements of primary care. Information was derived from the Primary Care Assessment Survey, a validated patient-completed questionnaire. RESULTS: Physicians were classified into 3 groups according to their reported hours of work: "overtime" (> 65 h/wk), "full time" (40-65 h/wk), and "part time" (< 40 h/wk). There was no statistically significant difference between the 3 groups of physicians in 10 of the 11 measures of primary care performance. Physicians who worked more than 65 hours per week were found to score significantly higher in the visit-based continuity of care category than physicians working fewer hours. Physicians working more than 65 hours per week were also found to be significantly less satisfied with the amount of time they had for family and personal life than the other 2 groups. CONCLUSIONS: Part-time physicians perform as well as full-time physicians in most aspects of primary care, including all interpersonal aspects of care, as reported by patients. Patients of physicians working more than 65 hours per week experienced higher levels of visit-based continuity of care than patients of physicians working fewer hours, but this appears to carry a cost to those physicians in the area of personal and professional satisfaction. Subsequent research should examine the relationship between physician workload and technical aspects of care.

Adult↗

Biological significance of iron-related magnetic resonance imaging changes in the brain.

Iron, an essential element for basic cellular metabolism, regularly accumulates in certain brain areas in normal subjects and in patients with certain diseases. Magnetic resonance imaging can depict iron deposition, offering a singular opportunity to correlate the regional iron content with the functional status of the human brain in vivo. We studied the relationship between age and the iron-related signal loss on T2-weighted images in basal ganglia, and observed a strongly significant signal decrease in the globus pallidus at the age of brain development (first two decades of life), but we found no such decrease in later years. Moreover, in healthy adults, subject-to-subject variability was relevant in changes due to iron deposition in magnetic resonance imaging. We found increased signal loss to be associated with poor performance on motor and specific cognitive tasks, suggesting that these image changes can provide functional information with respect to the brain in normal subjects.

Aged↗

Assessing the quality of care for children. Prospects under health reform.

The failure to pass federal health reform legislation this year does not mean that the health care crisis has been solved. As we look forward to predictably more incremental efforts to reduce costs, increase access, and improve quality, key issues from the most recent round of deliberations will undoubtedly reemerge. In the last session of Congress, private and public policymakers sent a clear signal that the era of accountability had arrived. In the health reform bills that Congress considered last year, a range of "measurement" strategies were put forth as essential elements for achieving accountability in a reformed health care system. For example, routine monitoring of the quality of care delivered by health plans and health providers was viewed as necessary to balance the impact of policies to control the cost of health care. Each of the major bills that were introduced this past year--Gephardt/Mitchell (S 1757/HR 3600), Cooper/Grandy (HR 3222), Breaux/Durenburger (S 1579), Nickles (S 1743), Chafee/Thomas (S 1770/HR 3704), and Wellstone/McDermott (S 491/HR 1200)--and the mark-up bills that have emerged from Senate and House committees have placed considerable emphasis on evaluating changes in access to health care and quality of care. Although the bills addressed issues related to financing, coverage, and the structure of the delivery system quite differently, they demonstrated much more consensus with regard to quality monitoring.

Child↗

Wound ballistics. A review of common misconceptions.

Attempts to explain wound ballistics (the study of effects on the body produced by penetrating projectiles) have only succeeded in mystifying it. This review explains the projectile-tissue interaction and presents data showing the location, type, and amount of tissue disruption characteristically produced by various projectiles. Data on tissue disruption are presented graphically as wound profiles. The major misconceptions in the field are listed, analyzed, and disentangled. Failure in adhering to the basic precepts of scientific method is the common denominator in all of the listed misconceptions; the result has been diversion of attention from the element essential to understanding and properly treating the gunshot wound--objective evaluation of the wound itself.

Animals↗

Evolution of tuberculosis control and prospects for reducing tuberculosis incidence, prevalence, and deaths globally.

CONTEXT: The United Nations Millennium Development Goals (MDGs) are stimulating more rigorous evaluations of the impact of DOTS (the WHO-recommended approach to tuberculosis control based on 5 essential elements) and other possible strategies for tuberculosis (TB) control. OBJECTIVE: To evaluate the prospects for detecting 70% of new sputum smear-positive cases and successfully treating 85% of these by the end of 2005, for reducing TB incidence, and for halving TB prevalence and deaths globally between 1990 and 2015, as specified by the MDGs. DATA SOURCES: TB case notifications (1980-2003) from DOTS and non-DOTS programs and cohort treatment outcomes (1994-2002) reported annually to the World Health Organization (WHO) by up to 200 countries, TB death registrations, and prevalence surveys of infection and disease. STUDY SELECTION: Case notification series that reflect trends in incidence, treatment outcomes from DOTS cohorts, death statistics from countries with WHO-validated vital registration systems, and national prevalence surveys of infection and disease. DATA EXTRACTION: Case reports, treatment outcomes, prevalence surveys, and death registrations from WHO's global TB database covering 1990-2003 to estimate TB incidence, prevalence, and death rates through 2015 for 9 epidemiologically different world regions. DATA SYNTHESIS: TB incidence increased globally in 2003, but incidence, prevalence, and death rates were approximately stable or decreased in 7 of 9 regions. The exceptions were regions of Africa with low (<4% in adults 15-49 years) and high rates (> or =4%) of HIV infection. The global detection rate of new smear-positive cases by DOTS programs increased from 11% in 1995 to 45% in 2003 (with the lowest case-detection rates in Eastern Europe and the highest rates in the Western Pacific) and could reach 60% by 2005. More than 17 million patients were treated in DOTS programs between 1994 and 2003, with overall treatment success rates more than 80% since 1998. In 2003, overall reported treatment success was 82%, with much variation among regions. The highest rates were reported in the Western Pacific region (89%) and lowest rates in African countries with high and low HIV infection rates (71% and 74%, respectively), in established market economies (77%), and in Eastern Europe (75%). To halve the prevalence rate by 2015, TB control programs must reach global targets for detection (70%) and treatment success (85%) and also reduce the incidence rate by at least 2% annually. To halve the death rate, incidence must decrease more steeply, by at least 5% to 6% annually. CONCLUSION: Reduction of TB incidence, prevalence, and deaths by 2015 could be achieved in most of the world, but the challenge will be greatest in Africa and Eastern Europe.

Africa↗

Evaluation of mental retardation: recommendations of a Consensus Conference: American College of Medical Genetics.

A Consensus Conference utilizing available literature and expert opinion sponsored by the American College of Medical Genetics in October 1995 evaluated the rational approach to the individual with mental retardation. Although no uniform protocol replaces individual clinician judgement, the consensus recommendations were as follows: 1. The individual with mental retardation, the family, and medical care providers benefit from a focused clinical and laboratory evaluation aimed at establishing causation and in providing counseling, prognosis, recurrence risks, and guidelines for management. 2. Essential elements of the evaluation include a three-generation pedigree: pre-, peri-, and post-natal history, complete physical examination focused on the presence of minor anomalies, neurologic examination, and assessment of the behavioral phenotype. 3. Selective laboratory testing should, in most patients, include a banded karyotype. Fragile X testing should be strongly considered in both males and females with unexplained mental retardation, especially in the presence of a positive family history, a consistent physical and behavioral phenotype and absence of major structural abnormalities. Metabolic testing should be initialed in the presence of suggestive clinical and physical findings. Neuroimaging should be considered in patients without a known diagnosis especially in the presence of neurologic symptoms, cranial contour abnormalities, microcephaly, or macrocephaly. In most situations MRI is the testing modality of choice. 4. Sequential evaluation of the patient, occasionally over several years, is often necessary for diagnosis, allowing for delineation of the physical and behavioral phenotype, a logical approach to ancillary testing and appropriate prognostic and reproductive counseling.

Diagnosis, Differential↗