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Biomedical subjects

R Bayer

Publications and source records attributed to R Bayer.

At least 73 records · Page 4Linked to original sources
PubMed1991

The great drug policy debate--what means this thing called decriminalization?

The contemporary debate over decriminalization mimics in almost every respect a debate that took place in the 1960s and early 1970s. In both the earlier challenges to the status quo and the current attack on the criminalization of drug use, critics have stressed the counterproductive consequences of the prohibitionist ethos. Although it is unlikely that America will move toward decriminalization in the near future, the current debate provides an opportunity to examine the underlying premises of the massive expenditure of resources on repressive measures.

Costs and Cost Analysis↗
PubMed1990

Topological disposition of the sequences -QRKIVE- and -KETYY in native (Na+ + K+)-ATPase.

The dispositions with respect to the plane of the membrane of lysine-905 in the internal sequence -EQRKIVE- and of lysine-1012 in the carboxy-terminal sequence -RRPGGWVEKETYY of the alpha-polypeptide of sodium and potassium ion activated adenosinetriphosphatase have been determined. These lysines are found in peptides released from the intact alpha-polypeptide by the extracellular protease from Staphylococcus aureus strain V8 and by trypsin, respectively. Synthetic peptides containing terminal sequences of these were used to prepare polyclonal antibodies, which were then used to prepare immunoadsorbents directed against the respective peptides. Sealed, right-side-out membrane vesicles containing native (Na+ + K+)-ATPase were labeled with pyridoxal phosphate and sodium [3H]borohydride in the absence or presence of saponin. The labeled alpha-polypeptide was isolated from these vesicles and digested with appropriate proteases. The incorporation of radioactivity into the peptides binding to the immunoadsorbent directed against the sequence pyrERXIVE increased 3-fold in the presence of saponin as a result of the increased accessibility of this portion of the protein to the reagent when the vesicles were breached by saponin; hence, this sequence is located on the cytoplasmic face of the membrane. It was inferred that the carboxy-terminal sequence -KETYY is on the extracytoplasmic face since the incorporation of radioactivity into peptides binding to the immunoadsorbent directed against the sequence -ETYY did not change when the vesicles were breached with saponin.

Amino Acid Sequence↗
PubMed1990

Legal and ethical issues relating to AIDS.

The worldwide AIDS epidemic has posed an extraordinary array of ethical and legal challenges. The work presented here reviews three issues at the heart of the matter: discrimination against HIV-infected people, the limits of confidentiality, and the exercise of coercive government powers to limit spread of the disease. Because the authors are most familiar with the U.S. experience, the review deals primarily with the history of the epidemic in the United States and public responses to it in that country.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Basic mechanisms underlying prenylamine-induced 'torsade de pointes': differences between prenylamine and fendiline due to basic actions of the isomers.

The calcium antagonists prenylamine and fendiline both bind with rather low affinity to the dihydropyridine (nifedipine) binding site. As calmodulin (CaM) antagonists, they both inhibit CaM-dependent enzymes and relax smooth muscle preparation in nearly the same concentration range. If compared with other calcium antagonists, their action on smooth muscle develops rather slowly and cannot be inhibited by the calcium agonist Bay k 8644. In contrast, basic pharmacology reveals major differences of the actions of prenylamine and fendiline in heart muscle, indicating that, after all, the change in structure close to the asymmetric carbon strongly influences the molecular action of the compounds and their respective isomers. The negative inotropic effect of racemic prenylamine is rather independent of stimulation rate, whereas fendiline preferably depresses contraction at high rate stimulation. The negative inotropic potencies are determined by the (-)-isomers, but only in the case of prenylamine the isomeric ratio of 6 reveals a considerable stereoselectivity of action. In low concentrations and preferably at low rate stimulation, (+)-prenylamine exerts a strong positive inotropic effect. At low rate stimulation, total duration of transmembrane action potential is prolonged by (+/-)- and (+)-prenylamine, but discretely shortened by (+/-)- and (+)-fendiline. At high rate stimulation, it is shortened by (+/-)- and (-)-prenylamine, but prolonged (only) at the very final repolarization level by (+/-)- and (-)-fendiline. The positive inotropic action of prenylamine and the prolongation of action potential at low stimulation rate can be interpreted as a calcium agonistic side-effect due to the action of the (+)-isomer. It seems possible that, under the condition of low heart rate, prenylamine (as reported for the calcium agonist Bay k 8644) increases the potential-dependent transmembrane calcium current. In addition, it is argued that during the long-lasting action potential, a reactivation of the calcium current induces early after-depolarizations. These effects are postulated to represent the main mechanisms triggering torsade de pointes during therapy with prenylamine. Though fendiline, from a chemical point of view, rather resembles prenylamine, its pharmacological profile is different. In particular, in regard to electrophysiology, torsade de pointes are not expected to be induced by fendiline.

Animals↗
PubMed1988

Reimbursement issues in clinical oncology.

In this multidisciplinary review, health-care specialists present practical solutions to the dilemma of rising costs v the need for adequate medical care for all Americans. The United States is the only advanced industrial society that makes ability to pay a critical determinant in health care. As the costs of patient care and insurance coverage escalate, the public demands greater value in insurance coverage with enhanced access to adequate care, clinical trials, and experimental therapies. Greater cooperation is needed between third-party payers, business, and government to create a system that provides optimal care today while supporting innovation and emerging technology for the future.

Antineoplastic Agents↗