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At least 865 records · Page 48Linked to original sources
PubMed2006

Animal carcinogenicity studies: 2. Obstacles to extrapolation of data to humans.

Due to limited human exposure data, risk classification and the consequent regulation of exposure to potential carcinogens has conventionally relied mainly upon animal tests. However, several investigations have revealed animal carcinogenicity data to be lacking in human predictivity. To investigate the reasons for this, we surveyed 160 chemicals possessing animal but not human exposure data within the US Environmental Protection Agency chemicals database, but which had received human carcinogenicity assessments by 1 January 2004. We discovered the use of a wide variety of species, with rodents predominating, and of a wide variety of routes of administration, and that there were effects on a particularly wide variety of organ systems. The likely causes of the poor human predictivity of rodent carcinogenicity bioassays include: 1) the profound discordance of bioassay results between rodent species, strains and genders, and further, between rodents and human beings; 2) the variable, yet substantial, stresses caused by handling and restraint, and the stressful routes of administration common to carcinogenicity bioassays, and their effects on hormonal regulation, immune status and predisposition to carcinogenesis; 3) differences in rates of absorption and transport mechanisms between test routes of administration and other important human routes of exposure; 4) the considerable variability of organ systems in response to carcinogenic insults, both between and within species; and 5) the predisposition of chronic high dose bioassays toward false positive results, due to the overwhelming of physiological defences, and the unnatural elevation of cell division rates during ad libitum feeding studies. Such factors render profoundly difficult any attempts to accurately extrapolate human carcinogenic hazards from animal data.

Animals↗
PubMed1997

French psychiatrists on the causes of madness, 1800-1870: an ambiguous attitude before an epistemological obstacle.

Modern psychiatry was born in the late eighteenth and early nineteenth centuries. At that time French psychiatrists had much to learn. One of their interests was in recognizing the causes of madness which they divided into physical and moral. This article aims to describe this moment in the history of medicine and to demonstrate how ancient ideas were reworked by these alienists. Above all it is argued that alienists struggled with a kind of disease that was regarded as unacceptable at the time.

France↗
PubMed2006

Systemic obstacles to battered women's participation in the judicial system: when will the status quo change?

The Canadian government has introduced numerous policies, guidelines, and mandates at the federal and provincial levels that recognize woman abuse as a serious social problem and violation of the law. Nonetheless, recent feminist research continues to expose laws and practices that fail woman abuse victims. The present study examined the experiences of women victims in domestic violence cases and the barriers they faced in dealing with the police, the courts, and social service agencies. Despite government initiatives, the study results corroborate previous findings indicating that many battered women feel further traumatized by ambivalent or discriminatory attitudes and practices prevalent within the system.

Adult↗
PubMed1983

Psychological obstacles to genetic education.

Medical knowledge and psychic reactions were studied in families affected by a progressive autosomal recessive disease, aspartylglucosaminuria. The information was given mainly in simple but written form. The subjects appeared to accept little correct information. Conversation did not appear to be of much value and intense emotional reactions were provoked. Attitudes towards the disease and patients could be divided into three groups: rational (30%), defensive (50%), and hostile (20%). The importance of early and repeated personal communication is emphasized.

Adult↗
PubMed2002

Loss of the imagined past: an emotional obstacle to medical compliance in kidney transplant recipients.

Among kidney transplant recipients, the concepts of grief and bereavement have been considered in terms of graft rejection, side effects of drugs, or death of the donor. However, our research suggests that even after a successful kidney transplantation, patients may present with feelings of bereavement, grief, or low mood, which may appear paradoxical because they have just received a much desired transplant. This sense of bereavement should be considered in terms of an imagined past, which may help to understand the patient's current mood changes and medical noncompliance. In the case report presented here, we have used the concept of systemic integrative psychotherapy to analyze change in a patient's life. Based on our research, we suggest that feelings of bereavement and grief are generated as patients come to terms with their past, which has been irretrievably lost to chronic illness, and contemplate their future. Feelings of grief and bereavement in the posttransplant period may be due to the loss of an imagined past, and must be differentiated from the bereavement the patient feels for the donor and the donor family. These feeling of loss, if not resolved, may lead to social isolation and medical noncompliance.

Activities of Daily Living↗
PubMed2002

Red cell antigens as functional molecules and obstacles to transfusion.

Blood group antigens (BGAs) can act as functional molecules but also can evoke autoantibodies and alloantibodies, causing autoimmune hemolytic anemia, hemolytic disease of the newborn and hemolytic transfusion reactions. In Section I, Dr. Marilyn Telen discusses physiologic and pathologic functions of RBC BGA-bearing molecules. She reviews some associations of BGAs with RBC membrane integrity and hemolytic anemia; association of BGAs with enzymatic and transport functions; and adhesion molecules expressed by RBCs, especially with reference to their pathophysiological role in sickle cell disease. In Section II, Dr. Lawrence Petz discusses the problems of providing blood for patients who have RBC autoantibodies. He provides an algorithm for excluding the presence of "hidden" alloantibodies, when all units appear to be incompatible due to the autoantibody. He emphasizes that clinicians should be aware of these approaches and not accept "the least incompatible unit." In Section III, Dr. George Garratty describes two processes, in development, that produce RBCs that result in RBCs that can be described as "universal" donor or "stealth" RBCs. The first process involves changing group A, B, or AB RBCs into group O RBCs by removing the immunospecific sugars responsible for A and B specificity by using specific enzymes. The second process involves covering all BGAs on the RBC surface using polyethylene glycol (PEG). Results of in vitro and in vivo studies on these modified RBCs are discussed.

Anemia, Hemolytic, Autoimmune↗