Wynik wyszukiwania w bazie Polska Bibliografia Lekarska GBL

Zapytanie: CLARK
Liczba odnalezionych rekordów: 3



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Tytuł oryginału: Biochemical characterization of the arginine degrading enzymes arginase and arginine deiminase and their effect on nitric oxide production.
Autorzy: Dillon Brian J., Holtsberg Frederick W., Ensor C. Mark, Bomalaski John S., Clark Mike A.
Źródło: Med. Sci. Monitor 2002: 8 (7) s.BR248-BR253, il., tab., bibliogr. 47 poz.
Sygnatura GBL: 313,278

Typ dokumentu:
  • praca doświadczalna
  • tytuł obcojęzyczny

    Wskaźnik treści:
  • zwierzęta
  • myszy
  • in vitro

    Streszczenie angielskie: Background: Nitric oxide (NO) is a biomediator believed to be synthesized primarily from extracellular arginine. Various methodologies have been used to inhibit NO synthesis so as to elucidate its physiological and pathophysiological functions. Several investigators have utilized various arginine degrading enzymes as a means of lowering extracellular arginine. Arginase, most commonly derived from mammalian sources, has been most often used. However, arginase has failed to inhibit NO synthesis. Herefore, a systematic biochemical characterization of arginase and arginine deiminase (ADI) derived from M. Hominus was undertaken. Material/Methods: The murine macrophage cell line N-9 was treated with either arginase or arginine deiminase to determine the effect on intracellular and extracellular arginine and nitric oxide production. Results: Arginase was found to have an alkaline pH optima (~9.5) with little enzyme activity at physiological pH. In contrast, the pH optima of ADI was ~6.5, retaining 70 p.c. of its activity at physiological pH. ADI had more than 1000 fold higher affinity for arginine (Km ~30 ćM for ADI vs ~45 mM for arginase), and was able to lower arginine levels to a much greater extent than arginase. ADI, unlike arginase, was effective in lowering extracelluar arginine in tissue culture media and inhibit NO production by the murine macrophage cell line N-9 in response to gamma interferon and LPS stimulation. Conclusions: These data suggest that ADI may be useful for delineating the role of NO in a variety of biological systems as well as determining the role of extracellular arginine in its synthesis.

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    Tytuł oryginału: AIDS research in developing countries: Do the ends justify the means?
    Autorzy: Clark Peter A.
    Źródło: Med. Sci. Monitor 2002: 8 (9) s.ED5-ED16
    Sygnatura GBL: 313,278

    Hasła klasyfikacyjne GBL:
  • aIDS

    Typ dokumentu:
  • tytuł obcojęzyczny

    Wskaźnik treści:
  • ludzie

    Streszczenie angielskie: Concrete ethical standards for human research are clearly stipulated in both international and national codes of ethics, and are meant to protect human subjects, especially the most vulnerable. A recent clinical study conducted from 1994 to 1997 by Dr. Thomas C, Quinn, M.D. has fueled the debate raging in the scientific community regarding the ethics of clinical AIDS research in developing countries. Quinn's conducted a community-based, randomized, controlled study of 15, 127 rural Ugandans to determine whether intermittent antibiotic treatment to reduce the prevalence of other sexually transmitted diseases would also reduce the rate of HIV transmission. Subsequently, the study identified 415 couples in which one partner was HIV positive and one was initially HIV negative and followed them prospectively for up to 30 months. Researchers were not permitted to inform the seronegative partner of the HIV status of the other partner. As a result, 90 of the initially HIV negative partners (21.7 p.c.) seroconverted during a follow-up period of 30 months. To allow for research studies in developing countries that are not permitted in the United states appears to make the Third Worl dequivalent to a'research sweat shop'. Developing nations offer easy access to patients, reduced costs, and less stringent regulations. This appears to create a double standard for medical research that is both ethically and humanly unacceptable, especially when other viable option exist. To allow relativism to seep into the international and national ethical standards will open the door to an idea that condones the possible abuse of those least able to rpotect themselves. Researchers have an ethical responsibility to uphold the integrity of these ethical standards. Failure to do so today may have a devastating impact on humanity in the future.

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    Tytuł oryginału: Confidentiality and the physician-patient relationship - ethical reflections froma a surgical waiting room.
    Autorzy: Clark Peter
    Źródło: Med. Sci. Monitor 2002: 8 (11) s.SR31-SR34, bibliogr. 7 poz.
    Sygnatura GBL: 313,278

    Hasła klasyfikacyjne GBL:
  • chirurgia

    Typ dokumentu:
  • tytuł obcojęzyczny

    Wskaźnik treści:
  • ludzie

    Streszczenie angielskie: The physician-patient relationship is the primary focus of ethics in medicine. It is both a personal and a professional relationship that is founded on trust, confidence, dignitiy and mutual respect. Trust is the bridge to the physician-patient relationship, and the burden is on the physician not only to expect the patient's trust but also to build a solid foundatin upon which the patient can place his or her trust. Great strides have been made by physicians in refining the physician-patient relatinship especially in understanding and respecting the patients' right of self-determination regarding medical decision-making and protecting their rights of privacy and confidentiality. However, further refinements are needed on both sides regarding this relationship. Breaches of confidentiality are cocurrig in places like surgical waiting rooms and as a result, the physician-patient relationship is being damaged. This article identifies some legitimate concerns and offers some concrete solutions so that the physician-patient relationship can be further refined and the virtues and rights that support it can be reinforced.

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