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Biomedical subjects

J P Lester

Publications and source records attributed to J P Lester.

9 recordsLinked to original sources

Modeling international cooperation in human space exploration for the twenty-first century.

The policy process of international cooperation in space exploration. including optimistic and pessimistic scenarios for the twenty-first century, is modeled and examined in this study. In the optimistic scenario, international cooperation involves a balanced and interdependent distribution of capabilities between states, their respective national space agencies and communities of space scientists and space engineers. Cooperation is characterized by interstate participation in critical path components and joint research and development. In the pessimistic scenario, international cooperation is structured and dominated politically and economically by powerful states vis-a-vis weaker states. Cooperation is limited to coordination of separate nationally approved projects and augmentation of capabilities in noncritical path components. On the basis of these two scenarios, policy predictions and implications relevant to exploration missions in the twenty-first century, such as a human-tended lunar base and human missions to Mars, are presented and discussed.

Europe↗

Needle and surface electrode somatosensory evoked potential normative data: a comparison.

Subdermal needle electrodes are now used routinely to record cortical somatosensory evoked potentials (SEPs). Investigators may make assumptions that: (1) SEP normative data obtained with surface electrodes can be used to interpret needle recordings, and (2) there is an increased potential for local dermal infection with needle electrodes. This investigation compared the waveform parameters obtained with surface and needle electrodes after stimulation of the tibial nerve, sural nerve, and L5 dermatome in 20 subjects. No statistically significant difference was found in the P latency, N latency, or P/N amplitude of the needle recordings as compared to the surface recordings. Additionally, 20 subjects studied for one week after four hours of needle insertion did not show any evidence of dermal infection. This study objectively documents no statistically significant difference between needle and surface SEP recordings and substantiates the use of surface normative data for needle SEP investigations.

Adult↗

Identification of a target cell antigen recognized by nonspecific cytotoxic cells using an anti-idiotype monoclonal antibody.

Nonspecific cytotoxic cells (NCC) are the teleost equivalent of mammalian natural killer (NK) cells. In the present study an anti-idiotypic monoclonal antibody (mAb 7D12) was generated against idiotopes on an mAb (mAb 6D3.2) that recognizes a putative receptor on NCC. The idiotypic specificity of mAb 7D12 was determined in competition assays by incubating biotinylated mAb 7D12 with mAb 6D3.2 hybridoma cells following preincubation with combinations of biotinylated 7D12 with either nonbiotinylated homologous or heterologous mAb. The ligand recognized by mAb 7D12 (determined by flow cytometry) was found on cells from the anterior kidney, spleen, thymus, PBL, liver, and brain. NCC lysis of IM-9 targets was inhibited 76% following preincubation of the target cells with different concentrations of mAb 7D12. The involvement of the ligand recognized by mAb 7D12 in the NCC lytic cycle was determined by showing that this mAb produced 50% inhibition of NCC conjugate formation with NC-37 target cells. Biochemical analysis using SDS-PAGE and Western blotting revealed that mAb 7D12 recognized 54 and 65 M(r) proteins in IM-9 target cell lysates. These studies demonstrated that an idiotope on a NCC specific anti-receptor mAb was an "internal image" of a target cell ligand. The anti-id mAb generated against this image (idiotope) inhibited NCC cytotoxicity and thus was equivalent to an NCC receptor that binds to a target cell ligand involved in NCC recognition.

Animals↗

Use of a new device in cannulation of the great vessels: cannula introducer.

To improve the existing complications of the arterial cannulation technique, an introducer was developed that could minimize the trauma to the vessel wall and intima, simplify the operation and avoid the usual complications such as air or emboli strokes, misdirection and malrotation of the cannula tip within the artery. The Introducer consists of an extendable blade proportionate to the size of the cannula to be inserted. The movement of the blade is accomplished by a trigger in the handle of the device. The cannula is also released by another trigger in the handle. Ninety heart patients in whom this device was used underwent open heart surgery, and there were no single case of a major stroke, air or thrombo-embolism, or undue blood loss. One patient developed a transient right hand paresis that subsided after removal of the arterial line. The results were compared to 65 patients with the current method of cannulation and in whom this device was not used. In this latter group there were five cases of major neurological deficits, one aortic dissection, one case of embolism to the leg and four cases of abnormal bleeding which necessitated takebacks in the first 24 hours of post-operative period.

Aged↗