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Biomedical subjects

J Seeman

Publications and source records attributed to J Seeman.

At least 19 recordsLinked to original sources
PubMed2004

Gene therapy using p21WAF-1/Cip-1 to modulate wound healing after glaucoma trabeculectomy surgery in a primate model of ocular hypertension.

Glaucoma is a common eye disease associated with elevated intraocular pressure (IOP). Lowering IOP is the only acceptable therapy for glaucoma and slows progression of the disease. Filtration surgery, which introduces a guarded ostomy through the sclera into the anterior chamber of the eye to allow the escape of aqueous humor, is the most reliable method for effective IOP lowering. Success of this surgery is limited by scarring of the ostomy, so this procedure is often accompanied by the use of antimetabolites, such as mitomycin C (MMC), to block the wound healing response. Although effective in preventing scarring, antimetabolites also yield unwanted side effects, such as hypotony and tissue degeneration due to cellular destruction. This study presents an alternative to antimetabolites by using gene therapy to introduce the human gene for p21(WAF-1/cip-1) (p21) to cause cell cycle arrest of surrounding cells rather than their destruction. In this procedure, p21 was delivered using a recombinant adenovirus to ocular hypertensive monkey eyes. These eyes then underwent filtration surgery. Results show that eyes treated with p21 exhibited open surgical ostomies by both functional and histological criteria, and did not display any side effects seen in control animals that were treated with MMC.

Adenoviridae↗
PubMed2002

3Alpha,5beta-tetrahydrocortisol effect on outflow facility.

3Alpha,5beta-Tetrahydrocortisol (THF) was administered topically and intracamerally to ocular normotensive cynomolgus monkeys to determine whether it affects outflow facility. Monkeys received THF either topically at a dose of 2 x 5 microl drops of 300 microg/10 microl twice daily for 4 days (n = 4) or 3 times daily for 10 days (n = 4) with 10% DMSO as vehicle to the control eye, or intracamerally via 2 ml anterior chamber (AC) exchange of 30 microg/ml THF with vehicle, 0.1% DMSO, to the control eye followed by a second AC exchange using 300 microg/ml THF with vehicle to the control eye. Outflow facility was measured by a two-level constant pressure AC perfusion after administration of eye drops or after baseline outflow facility measurement and AC exchange with THF solution. The results showed no effect on outflow facility in normotensive cynomolgus monkeys.

Animals↗
PubMed2000

Structural basis of the Ca(2+)-dependent association between S100C (S100A11) and its target, the N-terminal part of annexin I.

BACKGROUND: S100C (S100A11) is a member of the S100 calcium-binding protein family, the function of which is not yet entirely clear, but may include cytoskeleton assembly and dynamics. S100 proteins consist of two EF-hand calcium-binding motifs, connected by a flexible loop. Like several other members of the family, S100C forms a homodimer. A number of S100 proteins form complexes with annexins, another family of calcium-binding proteins that also bind to phospholipids. Structural studies have been undertaken to understand the basis of these interactions. RESULTS: We have solved the crystal structure of a complex of calcium-loaded S100C with a synthetic peptide that corresponds to the first 14 residues of the annexin I N terminus at 2.3 A resolution. We find a stoichiometry of one peptide per S100C monomer, the entire complex structure consisting of two peptides per S100C dimer. Each peptide, however, interacts with both monomers of the S100C dimer. The two S100C molecules of the dimer are linked by a disulphide bridge. The structure is surprisingly close to that of the p11-annexin II N-terminal peptide complex solved previously. We have performed competition experiments to try to understand the specificity of the S100-annexin interaction. CONCLUSIONS: By solving the structure of a second annexin N terminus-S100 protein complex, we confirmed a novel mode of interaction of S100 proteins with their target peptides; there is a one-to-one stoichiometry, where the dimeric structure of the S100 protein is, nevertheless, essential for complex formation. Our structure can provide a model for a Ca(2+)-regulated annexin I-S100C heterotetramer, possibly involved in crosslinking membrane surfaces or organising membranes during certain fusion events.

Acetylation↗
PubMed1999

Radiation safety system of the B-Factory at the Stanford Linear Accelerator Center.

The radiation safety system of the B-Factory accelerator facility at the Stanford Linear Accelerator Center is described. The radiation safety system, which is designed to protect people from prompt radiation exposure due to beam operation, consists of the access control system and the radiation containment system. The access control system prevents people from being exposed to the very high radiation levels inside a beamline shielding enclosure. The access control system consists of barriers, a standard entry module at every entrance, and beam stoppers. The radiation containment system prevents people from being exposed to the radiation outside a shielding enclosure due to either normal or abnormal operation. The radiation containment system consists of power limiting devices, shielding, dump and collimator, and an active radiation monitoring system. The inter-related elements for the access control system and radiation containment system, as well as the associated interlock network, are described. The policies and practices used in establishing the radiation safety system are also compared with the regulatory requirements.

California↗
PubMed1995

Herpes viruses in multicase families with rheumatoid arthritis.

OBJECTIVE: To investigate the rate and extent of infection by Epstein-Barr virus (EBV), cytomegalovirus, and herpesvirus 6 in families (affected and nonaffected members) with multiple cases of rheumatoid arthritis (RA). METHODS: Viral DNA was detected by polymerase chain amplification in cells from saliva and peripheral blood. Human leukocyte antigen pedigrees were characterized. RESULTS: Viral DNA, particularly EBV, was detected in increased frequency (p = 0.029) in the patients with RA compare to their nonaffected relatives. CONCLUSION: We suggest that in RA multicase families, increased frequency of viral infection is likely a consequence of the disease state and/or due to gene(s) as yet unidentified.

Aged↗
PubMed1989

Toward a model of positive health.

This article proposes a model of positive health based on a human-system framework. Such a framework is comprehensive in that (a) it encompasses all of the human system's behavioral subsystems (biochemical, physiological, perceptual, cognitive, and interpersonal), and (b) it permits a higher asymptote of health conceptualization and measurement than that afforded by Western biomedical theory. The article sets forth the conceptual basis of the model and reviews empirical studies that support the model. Finally, the article explores implications of the model for health research, for programs of health enhancement, and for the role of the behavioral sciences in health theory.

Adaptation, Psychological↗
PubMed1986

Effect of cytomegalovirus antigen on skin allograft survival in rabbits.

In experiments on rabbits it was found that the subcutaneous injection of cytomegalovirus (CMV) antigen into the draining lymphatic area of the skin allograft caused a decrease in graft survival. The difference of experimental versus control grafts was statistically significant. The finding supports some clinical data regarding the increased incidence of rejection episodes during CMV infection.

Animals↗
PubMed1980

Renal allograft function and cytomegaly.

A retrospective study in 20 seronegative and 61 seropositive (complement fixation) first cadaver donor graft recipients brought evidence that in cytomegaly, not the infection alone, but curtailment of azathioprine shortly after transplantation (or summation of both) may result in rejection and impaired graft survival. Preliminary data (accumulation of 125I-labelled fibrinogen in two and morphology of the graft in two other patients) showed that depression of graft function in cytomegaly is not necessarily due to rejection.

Azathioprine↗