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The ceramic reverse three-quarter crown for anterior teeth: laboratory procedures.

The laboratory procedures for making a Hi-ceram porcelain anterior reserve three-quarter crown are described. A core of high-fusing aluminum oxide is used as a coping on which tooth contours are restored with a compatible porcelain. Standard dental laboratory equipment is used and the technique can be quickly learned by any experienced ceramics technician.

Aluminum

Forecasting hospital laboratory procedures.

Improved forecasts of hospital laboratory procedures can provide the basis for better resource planning and enhanced operating efficiency. The research reported here-in describes how multiple regression models can be both a source of insight into causal relationships and a tool for achieving accurate monthly forecasts. Past research in this area may have overstated the statistical significance of findings because of a failure to address the potential effect of serial correlation. The present study uses the Cochrane-Orcutt regression procedure, rather than OLS, to overcome this problem. A model using inpatient admissions, acuity days, length of stay, discharge days and seasonal dummy variables is shown to account for 87% of the variation in the number of billable laboratory procedures. A simpler multiple regression model and a Winters' exponential smoothing model were found to provide excellent forecasts for laboratory procedures. In a one year out of sample evaluation, the annual percent forecast error was 0.7% for the regression model. This compares favorably to a percentage forecast error of 11.6% using subjective forecasting methods.

Forecasting

Laboratory procedures used in the diagnosis of systemic lupus erythematosus: a review.

The literature concerning the laboratory procedures presently available to aid in the diagnosis of systemic lupus erythematosus (SLE) was reviewed to determine which of these techniques could be most valuable in the detection and management of SLE patients. The LE cell test, once the laboratory basis for SLE diagnosis, was concluded to be insensitive, non-specific, and did not correspond to clinical activity of the patient. A second procedure, antinuclear-antibody detection, although very sensitive, was not specific for SLE; therefore, its value is limited for use as a screening technique to rule out SLE. The Farr anti-DNA precipitate immunoassay, used for the measurement of antibodies to DNA, was sensitive and specific, and also correlated well with the clinical condition of the patient. Therefore, the Farr binding assay is recommended as the laboratory procedure of choice since it is useful in monitoring disease activity and may contribute to earlier diagnosis and more precise management of SLE patients.

Antibodies, Antinuclear

Animal procedure laboratory surveys: use of the animal laboratory to improve physician confidence and ability.

Animal laboratories have been used for many years to teach procedures. Our department has a weekly swine laboratory devoted to training residents, interns and students in resuscitative procedures. Physicians who participated in our swine procedure laboratory over the past three years were queried as to their prelaboratory and postlaboratory comfort levels with six different resuscitative procedures, and 57 (76%) physicians responded. Statistical analysis of the data showed significant improvement in comfort levels for all six procedures. Every responder felt the swine laboratory helped or will help them perform the procedures on humans. We also surveyed all U.S. emergency medicine residency program directors from established programs regarding the status of their animal procedure laboratories, and 67 of the 68 (98%) directors responded. Of these responders, 62% offer an animal procedure laboratory. Overall, 97% of the residency directors rated the laboratory successful, and 97% of the residents rated the laboratory successful. Therefore, we conclude that an ongoing emergency medicine animal procedure laboratory is a valuable tool for improving physician-in-training ability and confidence.

Animals

Physician utilization of laboratory procedures to monitor outpatients with congestive heart failure.

Little is known about how different types of physicians use laboratory procedures in the management of outpatients with congestive heart failure. We therefore analyzed data from a national survey of randomly selected general practitioners, internists, and cardiologists to assess their management of outpatients with New York Heart Association class II congestive heart failure. Most of the 2704 respondents (90%) scheduled office visits between two and four months apart. Body weight, serum electrolytes, and chest roentgenograms were followed regularly by 98% or more of respondents, at median intervals of one to two months, three to five months, and 12 to 17 months, respectively. Serum digoxin levels in patients taking digoxin were followed by 90% of respondents at a median interval of 12 months. Echocardiography, radionuclide ventriculography, and exercise testing were used by fewer respondents (81%, 61%, and 61%, respectively), each at a median interval of 18 months or longer. Cardiologists were significantly more likely to follow patients using either echocardiography, radionuclide ventriculography, or exercise testing. The estimated yearly cost of following a class II congestive heart failure outpatient varied nearly fourfold from the lowest quartile of physicians ($303) to the highest ($1167). Cardiologists were disproportionately represented among the high-cost users. In addition, physicians who were younger or who practiced in an urban setting were significantly more likely to be high-cost users. Thus, simple laboratory tests were used most frequently to follow patients with heart failure, but differences in use of more expensive tests led to large differences in cost. Test use for similar patients is affected by characteristics of both the physician and practice setting.

Ambulatory Care

Development of a procedures laboratory evaluation tool.

Historically, it has been a relatively simple matter to assess students' classroom performance via internally developed evaluations. However, procedures laboratory proficiency of a student has been grossly neglected and has often fallen prey to the subjectivity of the evaluator. Accurate evaluation of students in the laboratory setting requires use of an effective evaluation instrument. The evaluation format described in this article was developed to effectively evaluate and critique the student's proficiency in radiographic positioning.

Alabama

[Displacement and distortion of non-precious ceramometal fixed bridges during the laboratory procedure. Non-precious metal].

The purpose of this study is to measure the three-dimentional displacement and distortion in the Non-precious (Ni-Cr) ceramometal bridges during laboratory procedure. At the time of pre-soldering stage, the author examined the phosphatic investment (low and high thermal expantion: ph, ps) to addition of gypsum investment which was usually to used to fix the position for soldering. The following results were obtained. 1. The displacement of the framework at the pre-soldering stage, in case of using phosphatic investment mixed by water (ph), it was small on the horizontal and vertical plane. And in the other case of mixing by 100% colloidal silica (ps), a kind of displacement was seen where the curve of the bridge opened as result of the position of two soldering bodies getting out of order from each other. So that phosphatic bonded investment, it can be used to because thermal expantion can be controlled, the soldering block. 2. Throughout the surface grinding of framework to grazing, displacement was minimal, at the time of opaque porcerain firing, the curve of the bridge closed but it had no effect on clinical adaptation. 3. In the case of assembling multi-unit non-precious ceramometal bridge mainly the displacement caused at pre-soldering stage, so it is important to check the adaptation after soldering.

Chromium Alloys

Enzymatic degradation of polygalacturonic acid by Yersinia and Klebsiella species in relation to clinical laboratory procedures.

As scored by several specified plating procedures, clinical and environmental strains of Yersinia enterocolitica, Yersinia pseudotuberculosis, and Klebsiella pneumoniae "Oxytocum" showed detectable, albeit generally weak, ability to digest polygalacturonic (pectic) acid. None of these bacterial strains had the vigorous and rapid pectolytic activity on these polygalacturonic acid-containing media that is typical of soft-rot Erwinia species, although some of the Oxytocum strains came fairly close. Analyses of the pectolytic enzyme contents of the cells and culture supernatants of the Yersinia and Klebsiella species revealed that readily detectable quantities of cell-bound polygalacturonic acid trans-eliminase and hydrolytic polygalacturonase were formed by the Yersinia and Klebsiella species; however, the total units of enzyme activity produced by these bacteria were, in general, lower than were produced by soft-rot Erwinia species. Furthermore, unlike the situation in soft-rot Erwinia cultures, these pectolytic enzymes of Yersinia and Klebsiella species were not excreted rapidly and massively into the growth medium. Cultures of other enterobacteria (Citrobacter species, Enterobacter species, Erwinia amylovora, Erwinia herbicola, Escherichia coli, Proteus species, Salmonella typhimurium, and Serratia marcescens) showed no pectolytic ability whatsoever by any of the plating procedures used and (to the extent they were so examined) produced no pectolytic enzymes detectable either in their cells or culture supernatants. This slow or weak release of pectolytic enzymes by Yersinia and Klebsiella species has a bearing on clinical laboratory procedures suitable for detecting their pectolytic activity; methods adequate for this purpose are detailed.

Bacteriological Techniques

Computerization of clinical laboratory procedure manuals.

Current code requires federally licensed clinical laboratories to have standard operating procedure manuals describing all tests performed. A computerized system for generating, revising, and excerpting manuals, which produces hard copy and microfiche, has been developed and appears to meet the regulatory criteria. The salient aspects of pertinent federal regulations, the features of the computerized system, the format of the manual, the users' experience therewith are described.

Computers

Occlusal accuracy in restorative dentistry: the role of the clinician in controlling clinical and laboratory procedures.

This paper describes the clinical and laboratory stages necessary to ensure the occlusal precision of fixed restorations. The important diagnostic stages, including elimination of mandibular dysfunction, the occlusal analysis and waxing of diagnostic casts, and the diagnostic use of provisional restorations, are outlined. The importance of having the clinician control all stages of laboratory work, including die trimming, mounting working casts on an articulator, the determination of both anterior and posterior tooth form, and the final occlusal adjustment of the restorations, is emphasized.

Dental Articulators

[A restraining device for rats for laboratory procedures].

The difficulty in handling not anaesthetized rats for laboratory purposes led the author to develop a specially made device, with two distinct parts: a wood base and a retainer. The latter is made with plastic tubes used in buildings, and holds effectively and harmless the animal, allowing manipulations and applications through holes in one of its face.

Animals

Quality control in flow cytometry for diagnostic pathology. I. Cell surface phenotyping and general laboratory procedures.

Flow cytometric analyses have become commonplace in the clinical laboratory for determining cell lineage and for quantitation of cells bearing a given phenotype. Because these assays are being conducted to support diagnoses or assist in determining therapy, it is crucial to ensure that these tests are highly accurate and reproducible within a laboratory and among laboratories involved in similar endeavors. This quality assurance has been slow evolving in clinical flow cytometry for a variety of reasons: the exquisite sensitivity and delicacy of the instrumentation that recognize previously undetectable variations in staining; the constant improvement of the hardware and software; the rapid development of new techniques and reagents of clinical interest; and the failure of any existing specialty or subspecialty to encompass all aspects of flow cytometry. This article provides an overview of quality assurance necessary for the flow cytometric analysis of cell surface markers. Practical experience, published studies, and suggested guidelines from accreditation agencies have been combined to develop the text.

Cell Separation

Laboratory procedures for detoxification of equipment and waste contaminated with brevetoxins PbTx-2 and PbTx-3.

Procedures are presented for the detoxification of laboratory equipment contaminated with brevetoxins PbTx-2 and PbTx-3. An in vivo bioassay using the Japanese madaka Oryzias latipes monitored toxin activity. Incubation for 10 min with 0.1N NaOH detoxified a lethal dose of either PbTx-2 or PbTx-3 to levels below the detection limit of the assay (less than 10 ng/mL). Decreasing the NaOH concentration required correspondingly longer incubation times. The potency of both toxins was also destroyed by incubation for 10-15 min at 500 degrees C. Steam autoclaving 30 min at 122 degrees C (18 psi) was not sufficient to detoxify brevetoxins. These results show that laboratory equipment will be decontaminated and rendered safe for normal handling by washing or soaking it in a dilute NaOH solution. Disposable waste can be either soaked in an NaOH solution prior to disposal or burned in an incinerator with a combustion chamber of at least 500 degrees C. Steam autoclaving, however, is not a viable method of decontamination.

Animals