Biomedical subjects

D E Mathews

Publications and source records attributed to D E Mathews.

12 recordsLinked to original sources

PubMed2000

Developing a perioperative peer performance appraisal system.

This article describes the course of action taken by one surgical department to develop and implement a peer appraisal process for nursing staff members. This rural, hospital-based, four-room surgical suite is staffed by 15.5 full-time equivalents (i.e., 22 staff members total) and includes full-time, part-time, and per diem nurses; surgical technologists; two aides; one scheduler; and one part-time educator. The author explains the steps the department took from beginning concept to implementation of the peer appraisal process.

Employee Performance Appraisal↗

PubMed1999

Complications of neodymium:YAG cyclophotocoagulation in the treatment of open-angle glaucoma.

A retrospective study was performed to determine the complications that occurred after cyclophotocoagulation. The condition of 33 eyes in 25 patients was observed from 1 month to 1 year after application of cyclophotocoagulation with a neodymium:YAG (Nd:YAG) laser for open-angle glaucoma. The number of treatment burns ranged from 16 to 50, and laser output energy ranged from 3 to 7 J. Complications included anterior uveitis in 14 eyes (42%), conjunctival injection in 12 eyes (36%), pain in 9 eyes (30%), and conjunctival hemorrhage in 5 eyes (15%). Corneal edema, intraocular pressure spikes, and corneal epithelial defects were each noted in three (9%) of the eyes treated, whereas cataracts developed in four (12%) of the eyes. Two eyes (6%) developed anterior segment ischemia with subsequent phthisis bulbi. Seven eyes (21 %) demonstrated no adverse reactions.

Adolescent↗

PubMed1999

Use of ubiquitin fusions to augment protein expression in transgenic plants.

A major goal of plant biotechnology is the production of genetically engineered crops that express natural or foreign proteins at high levels. To enhance protein accumulation in transgenic plants, we developed a set of vectors that express proteins and peptides as C-terminal translational fusions with ubiquitin (UBQ). Studies of several proteins in tobacco (Nicotiana tabacum) showed that: (a) proteins can be readily expressed in plants as UBQ fusions; (b) by the action of endogenous UBQ-specific proteases (Ubps), these fusions are rapidly and precisely processed in vivo to release the fused protein moieties in free forms; (c) the synthesis of a protein as a UBQ fusion can significantly augment its accumulation; (d) proper processing and localization of a protein targeted to either the apoplast or the chloroplast is not affected by the N-terminal UBQ sequence; and (e) single amino acid substitutions surrounding the cleavage site can inhibit in vivo processing of the fusion by Ubps. Noncleavable UBQ fusions of beta-glucuronidase became extensively modified, with additional UBQs in planta. Because multiubiquitinated proteins are the preferred substrates of the 26S proteasome, noncleavable fusions may be useful for decreasing protein half-life. Based on their ability to augment protein accumulation and the sequence specificity of Ubps, UBQ fusions offer a versatile way to express plant proteins.

Amino Acid Sequence↗

PubMed1996

Clinical grand rounds. Idiopathic central serous chorioretinopathy.

Idiopathic central serous chorioretinopathy is a very commonly seen disease process involving atypical RPE cells allowing the development of a neuroepithelial retinal detachment. Typically, this disease is self-contained and resolves spontaneously; however, on occasion, one must intervene by treating the area of atypical RPE with laser photocoagulation. Patients with ICSC should be monitored closely for any signs of choroidal neovascular membrane.

Choroid Diseases↗

PubMed1996

What is your diagnosis? Multiple sclerosis.

Multiple sclerosis is a demyelinating disease of the central nervous system that commonly presents with ocular manifestations. These ocular manifestations include vision loss and optomotor deficit. Treatment modalities should include treatment of the systemic disease as well as the ocular disease. New treatment protocol suggests that the best way to treat optic neuritis is with IV methylprednisolone, unless there is some serious contraindication for the patient. The use of interferon and cyclosporin as well as other anti-inflammatory agents may be useful in the future.

Adult↗

PubMed1994

Mechanistic aspects of tagetitoxin inhibition of RNA polymerase from Escherichia coli.

Tagetitoxin inhibits RNA synthesis directed by bacterial RNA polymerase, and the current study explores several mechanistic aspects of this inhibition. Tagetitoxin inhibition of in vitro RNA synthesis directed by Escherichia coli RNA polymerase is independent of the template DNA concentration. The toxin can block Escherichia coli RNA polymerase during elongation of a nascent RNA chain. In abortive initiation assays, the rate of dinucleotide formation is inhibited by tagetitoxin when initiated with ATP or CpA but not when AMP is used to initiate. Formation of longer oligonucleotides is inhibited by the toxin regardless of the initiating nucleotide. These abortive initiation studies indicate that tagetitoxin does not affect nucleotide substrate binding or phosphodiester bond formation and suggest that the toxin may interfere with a subsequent step. It is suggested that tagetitoxin affects the stability of nascent oligonucleotide binding and/or the translocation of the catalytic center with respect to the 3'-OH of nascent oligonucleotides.

Adenosine Triphosphate↗

PubMed1994

An overview of a feasibility study for the production of industrial enzymes in transgenic alfalfa.

The overall aims of the research are to develop genetically engineered alfalfa producing high levels of industrially important enzymes and to develop rapid methods for extracting and purifying these enzymes from alfalfa juice. Using a reporter gene beta-glucuronidase (GUS) as a model system, we were able to demonstrate production of a foreign protein in alfalfa and gain valuable insight into the molecular approaches required for the expression and accumulation of foreign proteins in leaf tissue. GUS activity varied among individual transformants, and GUS was expressed in all plant tissues. GUS activity was shown to segregate in sexual progeny. There was no correlation between copy number of the GUS gene and activity. We have recently demonstrated the production of Mn-dependent lignin peroxidase and alpha-amylase in transgenic alfalfa. Concurrent research in the agricultural engineering aspects of this feasibility study focused on extraction strategies for the recovery of alfalfa juice, and on an evaluation of methods for processing and concentrating the juice. Thus, we are in a position to use plants expressing enzymes that have current or potential industrial importance to complete a feasibility study, and determine whether we can indeed economically recover target enzymes from field-grown transgenic alfalfa plants. The technology developed for these enzymes can be used to extract other value-added products from plants in the future.

Bacillus↗

PubMed1994

Adverse reactions during retinal fluorescein angiography.

BACKGROUND: Fast sequence retinal fluorescein angiography is a commonly employed diagnostic procedure within the optometric practice with relatively few serious adverse reactions. A retrospective study was conducted to document the incidence of adverse reactions with this procedure. METHODS: A total of 1,173 patient charts who had undergone intravenous injection for retinal fluorescein angiography at a specility referral clinic or a referral clinic at a school of optometry. All patients had been intra-venously injected with 500 mg of sodium fluorescein in 25% or 10% solution. Adverse reactions were noted within the charts. RESULTS: The most common adverse reaction were nausea (.8% of patients) and urticaria (.6% of patients), with other reactions including emesis and hypoglycemia. Extravasation of dye was noted in .2% of patients. No acute anaphylaxis was noted. CONCLUSIONS: Fast sequence retinal fluorescein angiography is a relatively safe diagnostic test. However, one should be prepared to handle acute anaphylaxis within the office before administering the test because of previously published cases of life-threatening reactions.

Adolescent↗

PubMed1992

Blood chemistries, serology, and immunology.

Proper blood studies are necessary for the differential diagnosis of many diseases of the eye and visual system. The review of several blood chemistry, serology, and immunology tests is presented here with a brief review of the theory and use of these tests.

Blood Chemical Analysis↗

PubMed1990

Tagetitoxin inhibits RNA synthesis directed by RNA polymerases from chloroplasts and Escherichia coli.

Tagetitoxin, a chlorosis-inducing phytotoxin produced by Pseudomonas syringae pv. tagetis, inhibits RNA synthesis directed by chloroplast RNA polymerase. In isolated chloroplasts, tagetitoxin quickly and specifically reduced the incorporation of [3H]uridine into RNA. When it was added to transcriptionally active chloroplast protein extracts, the toxin directly inhibited incorporation of [32P]UTP into RNA. In addition, tagetitoxin inhibited in vitro RNA synthesis directed by the RNA polymerase from Escherichia coli. In vitro transcription reactions directed by chloroplast RNA polymerase or E. coli RNA polymerase are inhibited at tagetitoxin concentrations less than 1 microM. Nuclear RNA polymerase II purified from wheat germ was only affected at tagetitoxin concentrations greater than 100 microM during in vitro transcription. Tagetitoxin concentrations as high as 1 mM did not affect in vitro transcription reactions directed by RNA polymerase from bacteriophage T7 or SP6.

Bacteriophages↗

PubMed1990

Tagetitoxin: a new inhibitor of eukaryotic transcription by RNA polymerase III.

We demonstrate that tagetitoxin, a bacterial phytotoxin, preferentially inhibits eukaryotic RNA polymerase III. We used promoter-directed transcription of cloned genes in cell-free extracts to compare tagetitoxin inhibition of RNA polymerases from diverse sources. In HeLa cell extracts, accumulation of 5 S rRNA, and U6 snRNAs (transcribed by RNA polymerase III) was inhibited at 0.3-3.0 microM tagetitoxin but transcription from adenovirus 2 major late promoter (RNA polymerase II) was not significantly affected at concentrations below 30 microM. Tagetitoxin also inhibited promoter-directed RNA polymerase III transcription in cell-free extracts from Bombyx mori (pre-tRNA), and Saccharomyces cerevisiae (pre-tRNA) at 0.3-3.0 microM, concentrations that also inhibit chloroplast or bacterial promoter-directed transcription. In nonspecific transcription assays, partially purified B. mori RNA polymerase III was inhibited by tagetitoxin at concentrations that inhibit Escherichia coli RNA polymerase; purified calf thymus RNA polymerase II was not inhibited by tagetitoxin. Using injection into Xenopus laevis oocytes, we compared tagetitoxin effects on accumulation of U1 snRNA, hH2B mRNA (transcribed by RNA polymerase II), 5 S rRNA and U6 snRNA (RNA polymerase III), and 5.8 S rRNA (RNA polymerase I). In Xenopus oocytes, RNA polymerase III transcription was preferentially inhibited by tagetitoxin.

Amanitins↗

PubMed1979

Glucose requirements following burn injury. Parameters of optimal glucose infusion and possible hepatic and respiratory abnormalities following excessive glucose intake.

Glucose and leucine metabolism in 18 severely burned patients were studied using the primed constant infusion of U-13C-glucose and 1-13C-leucine, respectively. The leucine data were used to calculate rates of whole-body protein synthesis. In four additional burn patients and seven normal controls, the effects of exogenously infused insulin on the metabolism of infused glucose were evaluated. Also, the effect on leucine metabolism of adding insulin to infused glucose was tested and rates of protein synthesis were calculated. The protein studies were divided into two groups depending on the rate of glucose infusion. Protein synthesis was 4.3 + 0.54 g protein/kg/day during the lower infusion rates (1.4--4.5 mg/kg/min) and 5.17 + 0.19 g protein/kg/day during the higher infusion rates (4.7--9.3 mg/kg/min) (statistically different, p less than 0.05). However, when the high infusion rate group was divided into two subgroups (high, 4.7--6.8 mg/kg/min, and very high, 7.03--9.31 mg/kg/min), there was no difference in the rate of protein synthesis. When U-13C-glucose was infused during varying rates of unlabeled glucose infusion, we found that the per cent of CO2 coming from the direct oxidation of glucose rose rapidly at the lower infusion rates but reached a plateau at approximately 55% as the infusion rates exceeded 5 mg/kg/min. Addition of insulin did not affect the rate of glucose oxidation but did seem to exert a stimulatory effect on protein synthesis. It was concluded that there appears to be a maximal rate of glucose infusion, beyond which physiologically significant increases in protein synthesis and direct oxidation of glucose cannot be expected. Furthermore, there appears to be a physiological cost of exceeding the optimal glucose infusion rate, as indicated by increased rates of CO2 production during infusion as well as large fat deposits in the liver at autopsy in patients infused with large amounts of glucose.

Adolescent↗