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POSITRON EMISSION TOMOGRAPHY

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POSITRON EMISSION TOMOGRAPHY: See PET SCAN.

POST- : Prefix denoting ‘after’ in space or time. (See INTER-, PRE-, TRANS-) (MP)

POST TRAUMATIC STRESS DISORDER: Exceptionally harsh treatment can trigger a ‘last resort’ biological reaction described as body-mind dissociation or Post Traumatic Stress Disorder. During the aftermath of World War II, this phenomenon (called 'shell-shock' back then) was documented in detail in children who had been traumatized by their experiences in Nazi concentration camps, or working as forced laborers in Germany. The syndrome is not a new condition as it is the bane of the military and forms part of the ‘collateral damage’ of systematic human brutality. Scientists have known for a long time now that life-threatening situations propel the body and mind to engage in the struggle for survival by inactivating non-essential activity and emotions in order to channel all available energy to staying alive. This adaptation involves the stress response - the so called ‘fight or flight’ mechanism - that is crucial for survival. However, when the stress response is overly severe or sustained for too long, it has disastrous consequences for physical and mental health. Normally the workings of the brain allow a gradual process of desensitization of raw emotions, allowing the victim to look back at the traumatic event with a degree of detachment. Post Traumatic Stress Disorder sufferers, however, react with undiminished intensity years after the actual traumatic event. Specifically, they respond to unidentified, non-threatening environmental stimuli that trigger flashbacks, not only of the sights and sounds but also the smells of past traumatic memories. Acutely, these flashbacks are powerfully played over and over in the present but cannot be controlled or altered. Thus, the syndrome in children can be lifelong and not be fully recognized. With advancing age and memory deterioration, the reliving of past traumas can become more frequent and sharpened. (See COLLATERAL DAMAGE, GENERAL ADAPTATION SYNDROME, INSTITUTION OF WAR, STRESS). (IP)


POSTHUMOUS REPRODUCTION giving rise to offspring after one’s death; that is, from gametes or embryos that have been collected and stored frozen during life or soon after death. For example, using sperm from a decreased male to fertilize in vivo (donor insemination) or in vitro in conjunction with ICSI technology (see ASSISTED REPRODUCTIVE TECHNOLOGY). (IP)

POSTNATAL BLUES: See POSTPARTUM BLUES.

POSTNATAL DEPRESSION: a mood disorder which usually begins insidiously some weeks postpartum and is characterized by feelings of inadequacy and overwhelming sadness. The condition strikes approximately one in ten mothers and is of considerable severity as it is not a temporary loss of emotional control and cannot be simply attributed to hormonal instability. Surveys indicate that the women most likely to suffer postnatal depression are women who have delayed having children until their careers are established and who have had little contact with other mothers or support from their families. Nutritional deficiencies due to the heavy demands of pregnancy and breast-feeding, alcohol, smoking and other stresses may be contributing variables. Counselors urge new mothers to ask for help from their partner, family and friends as, ideally, parenting is not a single responsibility but one to be shared among those close to the mother and her baby. (See DEPRESSION, POSTNATAL PSYCHOSIS, POSTPARTUM BLUES). (IP)

POSTNATAL PSYCHOSIS: psychiatric illness after childbirth has been observed and documented since its description by Hippocrates in 400 BCE, and is a severe mental illness of mostly unknown etiology which can lead to violence such as suicide, child neglect and abuse. Fortunately, the condition is uncommon but still affects an estimated 1 in every 1,000 deliveries. Typically, the mother suffers illness of such severity that hospitalization with full psychiatric control is necessary to assure her safety and/or the safety of her infant. (See DEPRESSION, POSTNATAL DEPRESSION, POSTPARTUM BLUES). (IP)

POSTPARTUM BLUES: short periods of mild depression and mood swings which quickly return to normal but affect up to 80% of women any time between 2 and 5 days after the birth of their babies. Sleep deprivation, extra demands of the offspring and the re-establishment of the non-pregnant endocrine balance can all induce this condition in otherwise healthy women. In one theory, mild depression is attributed to the sudden removal of circulating  -endorphin - produced by the placenta in increasing amounts during pregnancy - and the consequent deprivation of its analgesic and euphoric properties. From the hormonal theory of depression has evolved a modern reanalysis of the old belief that violent postnatal endocrine fluctuations may be moderated by eating the placenta (many mammals routinely eat their placentae). Eating the placenta, however, is not a new western invention since, for thousands of years, Chinese women traditionally were given placental broth to fortify them after labor. (See DEPRESSION, POSTNATAL DEPRESSION, POSTNATAL PSYCHOSIS). (IP)


POT: See MARIJUANA.

POTENTIAL HEALTH RISK: any harm either physical or psychosocial/ psychological damage to a person due to a scientific, technological and medical application. It may also include disclosure of genetic information and other medical records of a person which may cause a possible damage in familial relationship and other social stigmatization and discrimination. (JA)

POWER ANALYSIS: See STATISTICAL POWER.

PPM: Parts Per Million.



PRAGMATISM: Actions which are based upon immediate practicalities rather than any theoretical considerations. In philosophy, pragmatism implies that the truth or content of a concept lies in its practical applicability or coherence with experience rather than theory. (MP)

PRAISE: (Latin: pretium "prize") An expression of admiration, commendation or gratitude to a person or deity. Positive encouragement of praiseworthy behavior is held in higher regard than attempts to educate using criticism or condemnation. (MP)

PRAYER: (Latin: prex) A personal communication or communion with God or another deity, often ritualized prayers of devotion but also often also a respectful request or entreaty to divinity. Prayer is a central focus of religious institutions and places of worship, aided by prayer books, beads and prayer wheels. For many people prayer provides a fundamental connection to their spiritual support and sense of identity. However, in a bioethical situation such as a sick child, prayer is an addition not an alternative to practical action. (MP)

PRE- : Prefix denoting ‘before’ in space or time. (See ANTE-, INTER-, POST-, TRANS-) (MP)

PRECAUTION: (Latin: praecavure "before + beware") An advance action, cautious circumspection or safeguard to protect against potential dangers or undesirable events. Accidents, uncertainty and unpredictability are factors leading to environmental damage and loss of life, and professionals in positions of power must take ethical responsibility for the future by exercising precaution. (See PRECAUTIONARY PRINCIPLE) (MP)

PRECAUTIONARY PRINCIPLE: An important modern concept for ecological, political and corporate management, the precautionary principle effectively states that "Where there are threats of serious or irreversible environmental damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation" (1992 Australian Intergovernmental Agreement on the Environment). Lack of full scientific knowledge of impacts should not be used as an excuse for development, with the onus of responsibility on the developer. Threats of irreversible environmental damage should be considered guilty until proven innocent. The principle of caution involves leaving ecological space as room for ignorance. All efforts should be taken to prevent non-sustainable development, habitat destruction or degradation, release of chemicals into the environment, global climate change, and loss of biodiversity. It is a useful tool to flag ignorance and uncertainty about eventualities such as undesirable ecological, social or corporate impacts, and to hold policy until increased scientific understanding of a problem has been achieved. The precautionary principle should be especially considered in environmental impact assessment, risk analysis, hazard management, political diplomacy and the scientific development of dangerous knowledge or technology. Many believe that the principle should become an established guideline for all policy-makers. (See ENVIRONMENTAL IMPACT ASSESSMENT, HUMAN EXTINCTION, PRECAUTION, RISK ANALYSIS). (IP & MP)

PRECISION: Precision is the correspondence of a measurement or repeated measurements within close specified limits. In mathematics, the precision of a number may be expressed as its power of 10. It is possible for a measurement to be precise but inaccurate. (See ACCURACY) (MP)

PRECOGNITION: (Latin: prae "before" + cognoscere "know") Prior knowledge of the occurrence of a specific event, for example a death revealed in a dream state, with no reasonable explanation for that awareness. One rationalization is that regular false expectations tend to be forgotten, whereas the occasional random precognitions which turn out to be true are noticeable and are remembered. (See CLAIRVOYANCE) (MP)


PRECONCEPTION INJURIES: Injuries to offspring attributed to damage sustained by either parent before the start of pregnancy. (DM)

PREDESTINATION: See DETERMINISM.

PREEMBRYO: The developing cells produced by the division of the zygote before the formation of the embryo proper at the appearance of the primitive streak. Also called pro-embryo. (DM)

PRE-EMPTION: Action in anticipation of the likely or possible action of another. (See GAME THEORY, PRE-EMPTIVE STRIKE, PREVENTIVE WAR) (MP)

PRE-EMPTIVE STRIKE: An early or surprise offensive attack, designed to prevent anticipated terrorism or military actions before the threat has actually materialized. It relies however upon a ‘reaction’ to the ‘possible’ intentions of another, which cannot necessarily be known, especially in a hawkish climate of fear or distrust. Pre-emptive strikes put conflicts on a hair-trigger, precipitating vengeance and a ‘use it or lose it’ mentality. (See AGGRESSOR NATION, HAWK, PREVENTIVE WAR) (MP)



PREFRONTAL CORTEX: See FRONTAL LOBE.

PREGNANCY: (Latin praegnans 'pregnant'). The gestational period between fertilization and the complete delivery of the fetus, placenta and fetal membranes, or the period between fertilization and the interruption of pregnancy as by spontaneous or induced abortion. A human pregnancy lasts approximately 36 weeks from the day of conception but is generally calculated 40 weeks from the first day of the last menstrual period. During the period of growth and development of the embryo and the fetus many physiological and psychological changes take place. (IP)

PREIMPLANTATION GENETIC DIAGNOSIS (PGD) A genetic technique that allows a single cell to be taken from an embryo in vitro in order to detect certain serious genetic conditions, before implantation. (see also GENETIC DIAGNOSIS) (JA)


PREIMPLANTATION SCREENING: See PREIMPLANTATION GENETIC DIAGNOSIS.

PREMARITAL TESTING: Premarital testing has been developed as a way to prevent genetic anomalies without recourse to abortion or discontinuation of neonatal intensive care. The idea seems to work most efficiently in groups, like some Orthodox Jewish sects, where prearranged marriages are the rule. One organisation, Dor Yesharim, started testing potential matches for Tay-Sacks several years ago. Privacy is guaranteed. If neither, or only one person is a carrier, they simply inform the families that they have no objection to the match, without mentioning which, or whether either person is a carrier. If both are carriers, they inform the families that they do not recommend the match. Among modern young people, where the rule is love marriages, rather than arranged marriages, it can be a subject for hot debate in the university classroom, whether a couple who have fallen in love, would cancel a wedding because of genetic test results. (FL)

PREMATURITY: inadequate birth weight due to preterm delivery where the duration of pregnancy was less than 37 weeks rather than poor fetal weight gain for a given duration of pregnancy which is conveyed as intrauterine growth retardation. (See INTRAUTERINE GROWTH RETARDATION). (IP)

PREMISES: Statements or evidence used to support an argument or conclusion. (See ASSUMPTION) (MP)

PRENATAL DIAGNOSIS: Determination of fetal status prior to birth. Methods include alpha-fetoprotein screening, amniocentesis, chorionic villi sampling. (See FETAL THERAPY, GENETIC SCREENING, PREIMPLANTATION DIAGNOSIS, SEX DETERMINATION) (GK)



PRENATAL SCREENING: See PRENATAL DIAGNOSIS.

PREPUCE: Technical name for the foreskin, or retractable fold of skin across the tip of the penis which is removed during circumcision; also the hood of skin protecting the clitoris. (See CIRCUMCISION) (MP)


PRESIDENT'S COMMISSION: The President's Commission was a body set up in the United States in the 1970s to deliberate on bioethical issues, and laid out a number of fundamental reports on bioethics issues. (DM)

PRESSURE / STATE / RESPONSE MODEL: A model often used by OECD countries in State of the Environment (SoE) reporting. It follows a causal relationship from the pressures which impact upon the state of the environment through to the development of adaptive responses. Driving forces may include population change, economic production, international trade, consumption trends, and flows of energy and materials. Pressures on the environment include energy use, agriculture, industry, developments and other human activities. State or condition of the environment is measured and reviewed, with reference to impacts upon land, air, water, biodiversity, ecology and human environments. Response requires close links to institutional policy, legislation, management decision-making, new technology, economic policies, international obligations and changing value systems. (See ENVIRONMENTAL IMPACT ASSESSMENT, STATE OF THE ENVIRONMENT REPORT) (MP)



PRESUMED CONSENT: An institutional policy of granting authority to health personnel to perform procedures on patients or to remove organs from cadavers for transplantation unless an objection is registered by family members or by the patient prior to death. (DM)

PRESYMPTOMATIC GENETIC TESTING: The genetic status of a person can be predicted with much certainty. A presence or absence of a gene (monogenetic) can cause a disorder. Testing of genetic disorder due to a single gene is often referred to as "presymptomatic genetic testing". Primarily carried out in healthy or asymptomatic individuals to provide information about that individual’s future health, with respect to specific inherited diseases. Such a test result may indicate that the individual has a high likelihood of developing the disorder or of excluding it. Presymptomatic testing is most frequently used in late onset autosomal dominant disorders such as Huntington’s Disease. (JA)


PREVALENCE: The number of cases of a given disease in a specified population at a designated time. (DM)

PREVENTION: See CURE.

PREVENTIVE DEPLOYMENT: The field deployment of peacekeeping troops for containment, deterrence and to maintain peace and order in an area of probable emerging conflict. For example, Macedonia was protected by a UN Preventive Deployment Force during the 1992 Yugoslav conflict. Distinction should be made between preventive deployment requested by the relevant government, pleaded for by affected people, and that which may be unwelcome. (See PEACE ENFORCEMENT, PEACE KEEPING, PRE-EMPTION, PREVENTIVE DIPLOMACY, PREVENTIVE WAR) (MP)

PREVENTIVE DIPLOMACY: Peace maintenance strategies and action to prevent disputes from escalating into armed conflict and to prevent the spread of conflicts, for example the United Nations in association with regional governments and organizations. Peaceful means for preventive diplomacy include mediation, negotiation, enquiry, arbitration and judicial settlement. Early prevention is the provision of a dispute resolution service well before armed conflict becomes imminent. Further information can be found in the UN Secretariat’s 1991 ‘Handbook on the Peaceful Settlement of Disputes between States’. (See CONFLICT RESOLUTION, FACILITATION, MEDIATION, NEGOTIATION, PEACE BUILDING, PEACE MAKING, PREVENTIVE DEPLOYMENT) (MP)


PREVENTIVE MEDICINE: The branch of medicine concerned with the prevention of disease and the promotion and preservation of health. (DM)

PREVENTIVE WAR: Euphemistic term for offensive military action based on temporary strategic advantage and the presumption of putative intentions. Preventive war is generally considered illegal under international law unless backed by United Nations Security Council resolutions. An example of so called ‘preventive war’ was the 2003 invasion of Iraq by the US ‘coalition of the willing’, on the supposed basis of preventing the link between terrorism and weapons of mass destruction. (See AGGRESSOR NATION, PRE-EMPTIVE STRIKE, PREVENTIVE DEPLOYMENT) (MP)


PRIMARY HEALTH CARE: Health care provided by the professional who is a patient's initial contact with the health care system and who may refer the patient to a specialist. (DM)

PRIMER: A short piece of DNA that promotes DNA synthesis by providing a site for the action of the enzyme, DNA polymerase, to add nucleotides at one end of the primer. (DM)

PRIMATES: A highly intelligent group mammalian animals belong to the order Primates with highly convoluted cerebral hemispheres, includes lemurs, loris, monkeys and apes. It includes also Homo sapiens. (JA)

PRIMITIVE STREAK: A pilling up of cells on the caudal end of the embryonic disc, providing the earliest evidence of the embryonic axis and the formation of the embryo proper. In human embryos this begins to occurs at about day 15. It is a progenitor of CNS. It is a boundary for embryo experiments to be allowed upto 14 days prior to streak development. (DM, IP)

PRIMORDIAL GERM CELL: precursor reproductive cells in an embryo or fetus. (JA)

PRIMUM NON NOCERE: 'Above all do no harm'. A principle widely cited in MEDICAL ETHICS (q.v.) that is stronger than DO NO HARM (q.v.). (MR)

PRINCIPLE OF DOUBLE EFFECT: See AQUINAS.

PRIONS: Were first proposed by Stanley Prusiner in 1984. They consist of an infectious protein which multiplies by converting normal protein molecules into infectious forms by inducing the normal, benign molecules to change their shape which makes the altered protein, now a prion, resistant to protease breakdown in brain tissue. As a result, plaques and gaps form in the infected person’s brain giving Prion diseases the collective name of Spongiform Encephalopathy (see BOVINE SPONGIFORM ENCEPHALOPATHY). The formation of plaques in the brain of infected individuals causes a progressive decline in cognition and motor function and, ultimately, death. The misfolding of a normal protein into a Prion can be caused by a number of factors which include a) iatrogenic procedures (see IATROGENIC and CREUTZFELDT-JAKOB DISEASE), 2) inherited 3) spontaneous mutation in individual’s genome. (IP)


PRIOR ART: That which is already known or available, part of the criteria of obviousness used in evaluating patent applications. (DM)

PRIORITY ANALYSIS: (MP) (See STRATEGIC MANAGEMENT)

PRISONER’S DILEMMA: A ‘game theory’ examining whether each of two prisoners charged with their crime, and without knowing what the other will do, should confess or stay silent. If both confess, they get a lesser sentence each, but if only one confesses he is rewarded and the one who stayed silent gets a long sentence. Neither confessing is the best option for them, but do they trust the other to stay silent and risk the long sentence? Broadly described, the dilemma is an inability to cooperate due to mutual distrust. This illustrates the need for collective solutions in international politics, environment and bioethics. (See GAME THEORY) (MP)

PRIVACY: Freedom from unauthorized oversight or observation. (DM)

PRIVILEGED COMMUNICATION: In law, a confidential statement made to a lawyer, physician, pastor, or spouse, which is privileged against disclosure in court if the privilege is claimed by the client, patient, penitent, or spouse. (DM)

PROBE: A sequence (DNA, RNA, oligo or cDNA) labelled with a radioactive or fluorescent compound that is used to detect a particular sequence in a mixture of nucleic acids. The probe hybridises specifically to its complementary nucleic acid sequence in the mixture, if this sequence is present. Being labelled, the target-probe duplex becomes visible, and can be recorded either as a +/- (for present/absent) signal in a dot or slot format, or as a band with a precise size in an autoradiography of a gel. Probes are mainly used to detect mutations and polymorphisms in DNA, or gene expression and transcript sizes in RNA. (GK)

PROBLEM: See OBJECTIVES, OBSTACLE, PROBLEM SOLVING.



PROBLEM FINDING: See PROBLEM SOLVING.

PROBLEM REPRESENTATION: See PROBLEM SOLVING.

PROBLEM SOLVING: See DECISION SUPPORT SYSTEMS, PROBLEM.

PROCESS: (Latin: processus ‘proceed’) A series of operations, or continuous action or function which results in changes to a system, resulting in some end such as production, legal change or environmental impact. To process is to put through procedures (e.g. planning, project implementation). ‘Process’ also has related meanings: ‘due process’ is adherence to legal proceedings; ‘processing’ is a certain treatment in manufacturing and photography; and computers ‘process’ or manipulate data to retrieve information. Of interest are natural processes: physical, chemical, ecological, physiological and psychological. Processes cause actions, changes, impacts, flows and outcomes. Process models and studies are powerful tools for environmental science and sustainability. (See ENVIRONMENTAL PROCESSES, ECOLOGICAL PROCESSES, ENVIRONMENTAL FLOWS, SYSTEM DYNAMICS, ENERGY) (MP)

PRO-CHOICE: The persons who believe that a woman has a right to determine whether to have an abortion. (see ABORTION, PRO-LIFE). (DM)

PRO-LIFE: The persons who believe that a woman should not have an abortion because it is killing a human life, the fetus. (see ABORTION, PRO-CHOICE). (DM)

PROCREATION: According to the French population geneticist Albert Jacquard, the process by which two individuals give rise to a third one, by mixing up half of each one’s genome, should be called procreation, meaning that a different being is created from two originally dissimilar sources. Instead, the process by which asexual individuals give rise to new, identical offspring, should be called reproduction, indicating that the genetic pool has not been modified from one generation to the next. In the actual bioethical debate around cloning, this is a key aspect in the understanding of the biological and societal implications of reproductive issues. (GK)




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