Biomedical subjects

P Samuelson

Publications and source records attributed to P Samuelson.

28 records · Page 2Linked to original sources

PubMed1995

Cell surface display of recombinant proteins on Staphylococcus carnosus.

A novel expression system for surface display of heterologous proteins on Staphylococcus carnosus cells has been developed. Taking advantage of the promoter and secretion signals, including a propeptide region, from the lipase gene of Staphylococcus hyicus and the cell wall-spanning and membrane-binding region of protein A from Staphylococcus aureus, efficient surface display of an 80-amino-acid peptide from a malaria blood stage antigen could be achieved. A serum albumin binding protein from streptococcal protein G was used both as a general reporter molecule and to increase the accessibility of the surface-displayed proteins. Immunoblotting, immunogold staining, and immunofluorescence on intact recombinant S. carnosus cells verified the presence of the propeptide, the malaria antigen, and the albumin-binding reporter protein on the bacterial surface. For the first time, fluorescence-activated cell sorting was used to analyze the presence of surface-displayed hybrid receptors on gram-positive bacteria.

Antigens, Protozoan↗

PubMed1994

Long-range interactions between DNA-bound ligands.

We have studied the interaction of the A:T specific minor-groove binding ligand 4',6-diamidino-2-phenylindole (DAPI) with synthetic DNA oligomers containing specific binding sites in order to investigate possible long-range interactions between bound ligands. We find that DAPI binds cooperatively to the oligomers. The degree of cooperativity increases with increasing number of binding sites and decreases with the separation between them. This dependence is paralleled by changes in the induced circular dichroism spectrum of DAPI, which decreases in intensity at 335 nm and increases at 365 nm. These results are consistent with an allosteric interaction of DAPI with DNA, where bound ligands cooperatively alter the structure of the DNA molecule. This structural change seems possible to induce under various conditions, including physiological. One consequence of allosteric binding is that ligands bound at a distance from each other sense each other's presence and influence each others' properties. If some regulatory proteins induce the same conformational change as DAPI, novel mechanisms for controlling gene expression can be anticipated.

Adenine↗

PubMed1993

The effect of prophylactic nitroglycerin infusion on the incidence of regional wall-motion abnormalities and ST segment changes in patients undergoing coronary artery bypass surgery.

The effects of nitroglycerin (NTG) on regional wall-motion abnormalities, ST segment changes, and the incidence of myocardial infarction (MI), cardiac failure, and mortality were studied in 30 patients undergoing coronary artery bypass. Patients received continuous infusions of either normal saline or NTG (1 microgram/kg per min [low dose] or 2 micrograms/kg per min [high dose]) beginning at anesthesia and continuing for 4 hours postoperatively. The occurrence of wall-motion abnormalities as detected by transesophageal echocardiography was 38 events in the normal saline group (N = 10). Significantly fewer events (p < 0.05) were recorded in the low dose and high dose NTG groups (20 events and 15 events, respectively) compared to controls. There were no significant differences between the control and NTG groups with regard to the incidence of Holter ST segment events or the incidence of MI, cardiac failure, or cardiac death. NTG reduced the incidence of echocardiographic wall-motion abnormalities in a dose dependent manner while having no significant effect on other parameters examined.

Coronary Artery Bypass↗

PubMed1993

Naproxen and paracetamol compared with naproxen only in coxarthrosis. Increased effect of the combination in 18 patients.

In a double-blind study of 18 patients with coxarthrosis the effect of 3 naproxen doses (0.5, 1.0, and 1.5 g daily) and 2 naproxen doses combined with paracetamol (0.5 g + 4 g daily and 1.0 g + 4 g daily) was investigated. Plasma levels of naproxen and paracetamol were measured (HPLC), and clinical assessment of pain, joint movement, activity of daily life and side-effects were performed at the end of the 5 treatment periods. A relationship was found between the 3 naproxen doses, naproxen plasma levels, pain at rest, and pain during movement. The combined treatment was more effective than treatment with the same naproxen dose alone. The effect of naproxen (0.5 g daily) combined with paracetamol (4 g daily) did not differ from that obtained during treatment with higher naproxen doses only. Furthermore, the effect of the highest naproxen dose was not better than the effect of the lower naproxen dose (1.0 g daily) combined with paracetamol. The main finding was that treatment with naproxen and paracetamol is more effective than treatment with higher naproxen doses alone.

Acetaminophen↗

PubMed1984

CONTU revisited: the case against copyright protection for computer programs in machine-readable form.

Professor Samuelson casts a critical eye on the Final Report of the National Commission on New Technological Uses of Copyrighted Works (CONTU) which recommended that copyright protection be extended to machine-readable versions of computer programs. CONTU appears to have misunderstood computer technology and misinterpreted copyright tradition in two significant respects. The Commission failed to take into account the historical importance of disclosure of the contents of protected works as a fundamental goal of both the copyright and patent laws. It also erroneously opined that the utilitarian character of a work was no bar to its copyrightability when both the statute and the case law make clear that utilitarian works are not copyrightable. Since computer programs in machine-readable forms do not disclose their contents and are inherently utilitarian, copyright protection for them is inappropriate. Congress acted on CONTU's recommendation without understanding the significance of these conceptual flaws. Professor Samuelson recommends the creation of a new form of intellectual property law specifically designed for machine-readable programs.

Computers↗

PubMed1978