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Biomedical subjects

W Merz

Publications and source records attributed to W Merz.

14 recordsLinked to original sources
PubMed1998

A graphical tool for ad hoc query generation.

Medical data are characterized by complex taxonomies and evolving terminology. Questions that clinicians, medical administrators, and researchers may wish to answer using medical databases are not easily formulated as SQL queries. In this paper we describe a graphical tool that facilitates formulation of ad hoc questions as SQL queries. This tool manages multiple attribute hierarchies and creates SQL query strings by navigating through the hierarchies. This interactive tool has been optimized using indexing to improve the overall speed of the query building and the data retrieval process. Indexed queries performed 5 to 100 times faster than query strings. However, query string generation time depends on the size of the taxonomies describing the hierarchies, while the index generation time depends on the size of the data warehouse.

Abstracting and Indexing↗
PubMed1985

Clip with enclosed spring for aneurysm surgery. Technical note.

A clip for aneurysm surgery has been designed with several unique features. The coil spring is fully hidden and protected within two hub sections so that it cannot be handled or become entrapped in tissue. The clip is milled from a piece of solid stock of nonmagnetic stainless steel to the desired size and shape by a computer milling process, thus avoiding the stresses and structural weaknesses caused by the bending, curling, and milling needed to prepare clips made from wire or sheet metal. The only means of opening the clip is by applying pressure to the solid milled surfaces, thus the spring cannot be weakened or bent by squeezing it or by trauma applied to the clip. The clip may be grasped in either a clip applier that holds the clip in one fixed position or in an applier that allows the clip to be rotated through an arc of 180 degrees.

Aneurysm↗
PubMed1984

Management of Acanthamoeba keratitis. A case report and review of the literature.

A recalcitrant corneal ulcer resulted in an extensive corneal opacity requiring penetrating keratoplasty. Histopathologic studies and subsequent cultures established the diagnosis of Acanthamoeba keratitis. A second transplant was performed due to a culture-proven recurrence of the keratitis in both the recipient and the graft, with progressive thinning. This has remained clear for six months on systemic ketoconazole and topical miconazole drops. This case demonstrates the difficulty in initial diagnosis of Acanthamoeba keratitis and the apparent successful medical control of the infection despite transplantation into an infected recipient bed.

Adult↗
PubMed1983

Spring clip for aneurysm surgery.

This report concerns a clip for aneurysm surgery which has (a) a stabilizing wire that prevents the scissoring of the blades, (b) a stronger coil spring that allows longer blades and a reduced possibility of slippage, and (c) grasping sites that allow the clip to be positioned in both an applier that holds the clip rigidly in one position, and in one that allows the clip to be rotated for optimal placement. The clip is made from stainless-steel wire 2 mm in diameter, which is larger than that used for other clips. The 2-mm diameter permits the clip to have wider clamping surfaces than other clips made from wire, it permits the grasping sites to be notched so that it may be held in a rotating clip applier, and permits the clip to be tooled for a stronger coil spring. The coil springs are of either a standard or a strong tension, and have opening pressures of approximately 175 g and 320 g, respectively.

Aneurysm↗
PubMed1981

Suction tubes for conventional and microscopic neurosurgery.

A set of suction tubes has been designed for both conventional neurosurgery done with the naked eye and microneurosurgery. All of the suction tubes have blunt, rounded tips that allow them to be used for manipulating tissue as well as for suction, and they are designed so that the surgeon's hand can rest comfortably on the wound margin while holding the tube in a pencil-type grip. The set includes the range of diameters needed for microsurgery and macrosurgery and the different lengths needed for superficial and deep intracranial and transsphenoidal operations.

Microsurgery↗
PubMedDate not supplied

In vitro survival of skin flora in heparin locks and needleless valve infusion devices.

OBJECTIVE: To determine the extent to which two types of infusion devices, the heparin lock and a needleless valve device, allowed the persistence of inoculated microorganisms. DESIGN: Experiment. SETTING: Clinical microbiology laboratory. OUTCOME MEASURES: Bacterial counts in infusion devices. INTERVENTION: Five of each type of device were inoculated with approximately 10(5) colony-forming units of a strain of Staphylococcus epidermidis and Enterobacter aerogenes and tested for growth at seven time intervals, from 10 minutes to 72 hours after inoculation. RESULTS: Both strains of bacteria were present in each device at every time interval tested, including 72 hours after inoculation. CONCLUSIONS: Bacteria introduced into a heparin lock or valve device may be isolated for prolonged periods of time. This suggests that if such devices are contaminated during use, they may be a potential source of infection. The risk of infection should be one major consideration in risk and benefit deliberations when choosing new products.

Catheters, Indwelling↗