Any process by which information is transmitted (made available or accessible) to intended audiences or target groups.
(See EVIDENCE-BASED MEDICINE.) Clinical trials aim to evaluate the relative effects of di?erent health-care interventions. They are based on the idea that there must a fair comparison of the alternatives in order to know which is better. Threats to a fair comparison include the play of chance and bias, both of which can cause people to draw the wrong conclusions about how e?ective a treatment or procedure is.
An appreciation of the need to account for chance and bias has led to development of methods where new treatments are compared to either a PLACEBO or to the standard treatment (or both) in a controlled, randomised clinical trial. ‘Controlled’ means that there is a comparison group of patients not receiving the test intervention, and ‘randomised’ implies that patients have been assigned to one or other treatment group entirely by chance and not because of their doctor’s preference. If possible, trials are ‘double-blind’ – that is, neither the patient nor the investigator knows who is receiving which intervention until after the trial is over. All such trials must follow proper ethical standards with the procedure fully explained to patients and their consent obtained.
The conduct, e?ectiveness and duplication of clinical trials have long been subjects of debate. Apart from occasional discoveries of deliberately fraudulent research (see RESEARCH FRAUD AND MISCONDUCT), the structure of some trials are unsatisfactory, statistical analyses are sometimes disputed and major problems have been the – usually unwitting – duplication of trials and non-publication of some trials, restricting access to their ?ndings. Duplication occurs because no formal international mechanism exists to enable research workers to discover whether a clinical trial they are planning is already underway elsewhere or has been completed but never published, perhaps because the results were negative, or no journal was willing to publish it, or the authors or funding authorities decided not to submit it for publication.
In the mid 1980s a proposal was made for an international register of clinical trials. In 1991 the NHS launched a research and development initiative and, liaising with the COCHRANE COLLABORATION, set out to collect systematically data from published randomised clinical trials. In 1994 the NHS set up a Centre for Reviews and Dissemination which, among other responsibilities, maintains a database of research reviews to provide NHS sta? with relevant information.
These e?orts are hampered by availability of information about trials in progress and unpublished completed trials. With a view to improving accessibility of relevant information, the publishers of Current Science, in 1998, launched an online metaregister of ongoing randomised controlled trials.
Subsequently, in October 1999, the editors of the British Medical Journal and the Lancet argued that the case for an international register of all clinical trials prior to their launch was unanswerable. ‘The public’, they said, ‘has the right to know what research is being funded. Researchers and research funders don’t want to waste resources repeating trials already underway.’ Given the widening recognition of the importance to patients and doctors of the practice of EVIDENCE-BASED MEDICINE, the easy availability of information on planned, ongoing and completed clinical trials is vital. The register was ?nally set up in 2005.... clinical trials
Before the Medicine’s Bill proceeded to the Statute book to become the Medicine’s Act 1968, so great was the threat to the practice of herbal medicine and sale of herbal preparations, that the profession and trade were galvanised into mobilising opposition. Thus, the British Herbal Medicine Association was formed in 1964. In the ensuing struggle, important concessions were won that ensured survival.
The BHMA is recognised by the Medicines Control Agency as the official representative of the profession and the trade. Its objects are (a) to defend the right of the public to choose herbal remedies and be able to obtain them; (b) to foster research in herbal medicine and establish standards of safety which are a safeguard to the user; (c) to encourage the dissemination of knowledge about herbal remedies, and (d) do everything possible to advance the science and practice of herbal medicine, and to further recognition at all levels.
Membership is open to all interested in the future of herbal medicine, including herbal practitioners, herbal retailers, health food stores, wholesalers, importers, manufacturers, pharmacists, doctors and research workers.
The BHMA produces the British Herbal Pharmacopoeia. Its Scientific Committee is made up of senior herbal practitioners, university pharmacologists and pharmacognosists. Other publications include: BHMA Advertising Code (1978), Medicines Act Advertising guidelines (1979), the Herbal Practitioner’s Guide to the Medicine’s Act (F. Fletcher Hyde), and miscellaneous leaflets on ‘Herbs and Their Uses’.
The BHMA does not train students for examination but works in close co-operation with the National Institute of Medical Herbalists, and with the European Scientific Co-operative on Phytotherapy.
Chairmen since its inception: Frank Power, 1964-1969; Fred Fletcher-Hyde, 1969-1977; Hugh Mitchell 1977-1986; James Chappelle 1986-1990; Victor Perfitt 1990-.
During the years the association has secured important advantages for its membership, particularly continuity of sale of herbal medicines in health food shops. It continues to maintain vigilance in matterss British and European as they affect manufacturing, wholesaling, retailing, prescribing and dispensing.
See: BRITISH HERBAL PHARMACOPOEIA and BRITISH HERBAL COMPENDIUM. ... british herbal medicine association
(AMA) a professional organization for US physicians. Its purposes include dissemination of scientific information through journals, a weekly newspaper, and a website; representation of the profession to Congress and state legislatures; keeping members informed of pending health and medical legislation; evaluating prescription and non-prescription drugs; and cooperating with other organizations in setting standards for hospitals and medical schools. The AMA maintains a comprehensive directory of licensed physicians in the US.... american medical association
Any mechanism by which a susceptible human host is exposed to an infectious or parasitic agent. These mechanism are:- 1. Direct transmission Direct and essentially immediate transfer of infectious agents (other than from an arthropod in which the organism has undergone essential multiplication or development) to a receptive portal of entry by which infection of humans may take place. This may be by touching, as in kissing, sexual intercourse or biting (direct contact); or by the direct projection of droplet spray onto the conjunctivae, or onto the mucous membranes of the nose or mouth during sneezing, coughing, spitting or talking (usually not possible over a distance greater than 3 ft) (droplet spread); or, as in the systemic mycoses, by direct exposure of susceptible tissue to soil, compost or decaying vegetable matter that contains the agent and where it normally leads a saprophytic existence. 2. Indirect transmission (a) Vehicle-borne Contaminated materials or inanimate objects such as toys, handkerchiefs, soiled clothes, bedding (fomites), surgical instruments or dressing (indirect contact); water, food, milk, biological products including serum and plasma, or anysubstance serving as an intermediate means by which an infectious agent is transported and introduced into a susceptible host through a suitable portal of entry. The agent may or may not have multiplied or developed in or on the vehicle before being introduced into man. (2) Vector-borne (i) Mechanical:- Includes simple mechanical carriage by a crawling or flying insect through soiling of its feet or proboscis, or by passage of organisms through its gastrointestinal tract. This does not require multiplication or development of the organism. (ii) Biological:- Propagation (multiplication), cyclic development, or a combination of them (cyclopropagation) is required before the arthropod can transmit the infective form of the agent to man. An incubation period (extrinsic) is required following infection before the arthropod becomes infective. Transmission may be by saliva during biting, or by regurgitation or deposition on the skin of agents capable of penetrating subsequently through the bite wound or through an area of trauma following scratching or biting. This is transmitted by an infected invertebrate host and must be differentiated for epidemiological purposes from simple mechanical carriage by a vector in the role of a vehicle. An arthropod in either role is termed a vector. (c) Air-borne The dissemination of microbial aerosols with carriage to suitable portal of entry, usually the respiratorytract. Microbial aerosols are suspensions in air of particles consisting partially or wholly of microorganisms. Particles in the 1 to 5 micron range are quite easily drawn into the lungs and retained there. They may remain suspended in the air for long periods of time, some retaining and others losing infectivity of virulence. Not considering as airborne are droplets and other large particles, which promptlysettle out; the following are airborne, their mode of transmission indirect: (i) Droplet nuclei: Usually the small residues which result from evaporation of droplets emitted by an infected host. Droplet nuclei also may be created purposely by a variety of atomising devices, or accidentally, in microbiology laboratories or in abattoirs, rendering plants, autopsy rooms, etc. They usuallyremain suspended in the air for long periods of time. (ii) Dust: The small particles of widely varying size which may arise from contaminated floors, clothes, beddings, other articles; or from soil (usually fungus spores separated from dry soil by wind or mechanical stirring). Note: Air conditioning and similar air circulating systems may play a significant role in air-borne transmission (e.g. Legionnaire’s disease).... transmission
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