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Biomedical subjects

A Park

Publications and source records attributed to A Park.

At least 19 recordsLinked to original sources
PubMed2001

Heart mender.

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Cardiology↗
PubMed2001

Cancer spotter.

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History, 21st Century↗
PubMed2001

The case for David Ho.

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Acquired Immunodeficiency Syndrome↗
PubMed2001

The development and implementation of a computerized database for clinical research in minimal access surgery. An international pilot study.

BACKGROUND: The measurement of outcomes after minimal access surgery (MAS) relies on the maintenance of an accurate, prospective clinical database. The development of a system for data management often proves to be challenging, expensive, and extremely time-consuming. METHODS: We developed a computerized relational database for MAS using Microsoft Access 97 to reside on a hospital server, taking advantage of existing network connections, security, and backup systems. The design of the database includes a point-and-click approach with dropdown boxes for diagnoses, procedures, and complications (limited free-text entry). A fundamental feature of this database allows surgeons and surgical trainees to record clinical information at the point and time of data acquisition. RESULTS: A "beta version" or fully functional draft of the database was presented to a group of surgeons from a variety of specialties (n = 8), and a structured interview based on a questionnaire was used to elicit the surgeon's evaluations of the database. Using the information from the interviews, the database was extensively revised and restructured. CONCLUSIONS: We have developed a relational database that reflects the needs of surgeons interested in clinical research. This database may serve as a template for other centers. It can be expanded to adopt new procedures or modified for other surgical specialties.

Attitude of Health Personnel↗
PubMed2001

Development of poly-(D,L-lactide--coglycolide) microsphere formulations containing recombinant human vascular endothelial growth factor to promote local angiogenesis.

Although preclinical animal studies have demonstrated the utility of recombinant human vascular endothelial growth factor (rhVEGF) in promoting neovascularization in regions of ischemia, rhVEGF systemic administration did not provide clinical benefit to patients in recent placebo-controlled Phase II clinical trials. The amount of rhVEGF localized in the ischemic region after systemic administration is minimal and does not persist for more than 1 day. A greater persistence of rhVEGF at the region of ischemia may provide an increased angiogenesis with the eventual formation of patent blood vessels to restore nourishment to the tissues. We sought to develop a formulation of rhVEGF in poly(D,L-lactide--co-glycolide) (PLG) microspheres that would provide a continuous local delivery of intact protein. A stable formulation of rhVEGF for encapsulation contained a small amount of a stabilizing sugar, trehalose. Addition of excess trehalose increased the rate of release from the PLG. In addition, PLG with free acid end groups appeared to retard the initial release of rhVEGF by associating with it through ionic interactions at the positively charged heparin binding domain. rhVEGF was released continuously for 21 days with a very low (less than 10%) initial burst. The released rhVEGF aggregated and hydrolyzed over time and lost heparin affinity but not receptor affinity. The compression molding of rhVEGF PLG microspheres into disks yielded formulations with a low initial release and a lag of 10 days followed by complete release. The PLG microsphere formulations were assessed in the corneal implant model of angiogenesis and generated a dose-dependent angiogenic response. These formulations were also administered intravitreally and subretinally, generating local neovascularization comparable to the human disease states, vitroretinopathy and age-related macular degeneration, respectively. The rhVEGF PLG formulations may increase local angiogenesis without systemic side effects and may also be useful in the development of ocular disease models.

Animals↗
PubMed2001

Inhibition of neutrophil elastase prevents cathelicidin activation and impairs clearance of bacteria from wounds.

The host defense roles of neutrophil elastase in a porcine skin wound chamber model were explored. Analysis of wound fluid by acid-urea polyacrylamide gel electrophoresis, Western blot, and bacterial overlay confirmed that the neutrophil-derived protegrins constituted the major stable antimicrobial polypeptide in the wound fluid. The application to the wound of 0.10 and 0.25 mM N-methoxysuccinyl-alanine-alanine-proline-valine (AAPV) chloromethyl ketone, a specific neutrophil elastase inhibitor (NEI), blocked the proteolytic activation of protegrins and diminished the associated antimicrobial activity as detected by radial diffusion assay against Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans or by bacterial gel overlay against S epidermidis and E coli. The application of the related cathepsin G inhibitor (CGI), benzyloxycarbonyl-glycine-leucine-phenylalanine (ZGLF) chloromethyl ketone, had no effect. In wound chambers that received 10(6) colony-forming unit (CFU)/mL of S epidermidis, the presence of NEI significantly decreased the 24-hour clearance of bacteria from the wound compared to wounds treated with CGI or solvent only. Neither inhibitor, at 0.10 or 0.25 mM concentration, affected leukocyte accumulation or degranulation in the wound chambers. The in vitro microbicidal decrement due to NEI was restored by an amount of the specific protegrin (PG-1), which was equivalent to the measured difference of protegrin between control and inhibited chambers. Administration of 1 microg/mL exogenous PG-1 4 hours after chamber preparation was sufficient to normalize in vivo antimicrobial activity. Although pharmacologic NEIs are promising candidates as anti-inflammatory drugs, they may impair host defense in part by inhibiting the activation of cathelicidins by neutrophil elastase.

Animals↗
PubMed2001

Laparoscopic surgery of the spleen: state of the art.

INTRODUCTION: Laparoscopic splenectomy (LS) offers superior visualization and access to the spleen and avoids the major laparotomy incision necessary in open splenectomy (OS). This review summarizes the current knowledge of laparoscopic techniques for splenectomy from the perspective of surgeons whose combined experience now totals 340 cases. BACKGROUND AND DISCUSSION: While LS has been applied across the spectrum of splenic diseases, it is most indicated in treatment of a benign hematologic condition with a normal or slightly enlarged spleen as seen in autoimmune thrombocytopenic purpura (ITP), autoimmune deficiency syndrome-related ITP, hemolytic anemia, or spherocytosis. Both anterior and lateral approaches have been used for LS. While benefits of the anterior approach include access to the splenic artery along the superior border of the pancreas within the lesser sac, thus securing vascular control early in the procedure, the lateral approach allows for improved exposure of and access to the splenic pedicle. Also, mechanics and sequence of dissection are enhanced and more intuitive to the surgeon using the lateral approach, and the tail of the pancreas is more easily identified. Potential perioperative complications of LS include hemorrhage, injury to the tail of the pancreas, and deep vein thrombosis. The most common criticisms facing LS are the potential for missed accessory spleens, longer operating time, and greater operating room costs compared to OS. However, while LS requires a longer operating time than OS, studies indicate shorter postoperative hospital stays for LS versus OS patients in comparable cases, which can, in turn, reduce the total hospital cost for the procedure. CONCLUSION: Although LS continues to pose certain technical challenges--such as management of the massive spleen, specimen extraction, and identification of remotely located accessory spleens--its advantages over OS in terms of faster postoperative recovery, shorter hospital stay, and equivalent or lower perioperative morbidity are now well established. Indications for LS and more laparoscopic spleen-conserving surgery are likely to broaden.

Contraindications↗