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Biomedical subjects

S Glaze

Publications and source records attributed to S Glaze.

13 recordsLinked to original sources
PubMed2000

The Arabidopsis NPR1/NIM1 protein enhances the DNA binding activity of a subgroup of the TGA family of bZIP transcription factors.

The Arabidopsis NPR1 gene is essential in activating systemic, inducible plant defense responses. To gain a better understanding of NPR1 function, we conducted a yeast two-hybrid screening procedure and identified a differential interaction between NPR1 and all known members of the Arabidopsis TGA family of basic leucine zipper transcription factors. In the electrophoretic mobility shift assay, NPR1 substantially increased the binding of TGA2 to its cognate promoter element (as-1) as well as to a positive salicylic acid-inducible element (LS7) and a negative element (LS5) in the promoter of the pathogenesis-related PR-1 gene. Proteins encoded by npr1 mutants interacted poorly with TGA2 and did not substantially increase TGA2 binding to the as-1, LS5, or LS7 elements, thus establishing a link between the loss of disease resistance and the loss of TGA2 interaction and NPR1-enhanced DNA binding. Coupled with observations that the DNA binding activity of TGA factors is deregulated in npr1 plants, the results suggest that NPR1-mediated DNA binding of TGA2 is critical for activation of defense genes.

Arabidopsis↗
PubMed1999

A starch-branching enzyme gene in wheat produces alternatively spliced transcripts.

A wheat gene, denoted Sbe1, encoding a type I starch-branching enzyme (SBEI) was isolated from a genomic library and shown to comprise 14 exons distributed over a 5.7 kb DNA region. Analyses of kernel RNA by 5' rapid amplification of cDNA ends (5'-RACE) and reverse transcription-polymerase chain reaction (RT-PCR) demonstrated a considerable sequence variation at the 5' ends of SBEI gene transcripts. DNA sequence alignments between the 5'-RACE products and the Sbe1 genomic DNA indicated that the first two exons and first intron were differentially processed to generate three classes of the mature transcript. One form of the SBEI gene transcript in 12-day old kernels contained the exon I+II+III combination at the 5' end, whereas other forms differed by inclusion of intron 1 or exclusion of exon II sequences. RT-PCR analysis of Sbe1-uidA::nptII chimeric mRNA produced in transgenic wheat cultured cells confirmed that the isolated Sbe1 was able to produce all three forms of SBEI gene transcripts by alternative splicing of the primary mRNA. The variants of processed Sbe1 mRNA were potentially translated into N-terminal variants of the SBEI precursor with different transit peptide sequences.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1994

Exposure rates during special procedures with C-arm type fluoroscopic systems.

PURPOSE: To test for regulatory compliance of free-in-air entrance air kerma rates (EAKR) in C-arm type fluoroscopic equipment, measurements are frequently made under minimum source-to-image receptor distance (SID) and at 300 mm from the image intensifier. However, this is not representative of normal patient geometry, and the automatic brightness controls on these units frequently increase tube output as SID increases. This study investigated effects of these circumstances on actual EAKRs. MATERIALS AND METHODS: Typical patient geometries were observed and recorded for 23 consecutive body vascular procedures. EAKRs were measured under compliance and normal patient geometries with use of five modern C-arm type systems for special procedures. RESULTS: SIDs of 1 m were typical when rapid film changers were employed and the patient's entrance skin surface was typically 500 mm from the image receptor. Actual EAKRs were found to be up to 2.5 times those measured under compliance geometry. CONCLUSION: Actual patient geometries should be used to ensure correct estimates of EAKRs.

Fluoroscopy↗
PubMed1989

Effectiveness of radiation control program for Dornier HM3 lithotriptor.

Radiation exposure during extracorporeal shock-wave lithotripsy (ESWL) was calculated using a "worst-case method" in 135 randomly selected patients. The patients were divided into four groups according to body weight: small (less than 140 pounds), medium (141-180 pounds), large (181-220 pounds), and very large (greater than 220 pounds). Average skin exposure was found to be 15.2 R (from 1.2 to 95.6 R). After implementation of a "radiation awareness program" radiation exposure was calculated in 128 cases (matched for body weight and stone burden) and average exposure was 9.5 R (from 0.9 to 33.4 R) with a reduction of 20, 37, 33, and 62 percent for each group, respectively. Radiation exposure reduction was primarily due to a reduction in the number of radiographic "snapshots" taken as a result of preferential use of special-mode fluoroscopic "stills."

Body Weight↗
PubMed1987

Patient and personnel exposure during extracorporeal lithotripsy.

Extracorporeal shock wave lithotripsy (ESWL) has provided a nonsurgical approach to treatment of renal stones. The Dornier lithotripter uses dual image intensified x-ray systems to center the stone before treatment. Three imaging modes are offered: a fluoroscopic mode and two video spot filming modes. The average entrance exposure to the stone side of the typical patient at our facility is 2.6 X 10(-3) C kg-1 (10 R) [range: 0.5-7.7 X 10(-3) C kg-1 (2-30 R)] which is comparable and often much less than that reported for percutaneous lithotripsy. Recommendations are made for minimizing patient exposure. Scattered radiation levels in the lithotripter room are presented. We have determined that Pb protective apparel is not required during this procedure provided x-ray operation is temporarily halted should personnel be required to lean directly over the tub to attend to the patient. If the walls of the ESWL room are greater than 1.83 m (6 feet) from the tub, shielding in addition to conventional construction is not required.

Humans↗
PubMed1984

Defects in new protective aprons.

Upon careful examination, several defects have been detected in new protective aprons . The nature of the defects is identified and described. Although the occurrence of such defects has not exceeded 5%, they are significant enough to warrant return of the lead apron to the supplier. It is recommended that the integrity of all new protective aprons be verified upon receipt as well as at yearly intervals.

Fluoroscopy↗
PubMed1982

A computer-assisted procedure for estimating patient exposure and fetal dose in radiographic examinations.

A computer program for calculating patient entrance exposure and fetal dose for 11 common radiographic examinations was developed. The output intensity measured at 70 kVp and a 30-inch (76-cm) source-to-skin distance was entered into the program. The change in output intensity with changing kVp was examined for 17 single-phase and 12 three-phase x-ray units. The relationships obtained from a least squares regression analysis of the data, along with the technique factors for each examination, were used to calculate patient exposure. Fetal dose was estimated using published fetal dose in mrad (10(-5) Gy) per 1,000 mR (258 microC/kg) entrance exposure values. The computations are fully automated and individualized to each radiographic unit. The information provides a ready reference in large institutions and is particularly useful at smaller facilities that do not have available physicians who can make the calculations immediately.

Body Burden↗
PubMed1978

Interpatient microbiological cross-contamination after dental radiographic examination.

Pairs of patients were evaluated for microbiological cross-contamination after radiographic examination. In 30 of these pairs of patients there was the possibility of transference of S pyogenes, S aureus, or D pneumoniae. Such transference was observed in 23 (77%) of these 30 pairs of patients. The vectors for such transfer include the hands of the X-ray technician and the radiographic equipment. Further, it was found that each of these organisms would survive for at least 48 hours after being placed on an X-ray tube. Since interpatient microbiological cross-contamination can occur after routine radiographic examination, in some cases, disinfection of the radiographic equipment is indicated.

Cross Infection↗
PubMedDate not supplied

Dosimeter placement in the Rando phantom.

Each section of the Alderson Rando phantom contains a tissue-equivalent plastic coating layer approximately 2 mm thick, applied to both faces. This compensates for material removed in the sawing process. Conventional use of thermoluminescent dosimeters positions them totally or partially within the coating layer. Analysis shows that, in the lung region, dosimeters placed in this layer received a dose averaging 39% lower than those placed at midsection. Where bony structures interfere, some dosimeters in the coating layer received an 18% higher dose than those at midsection. Therefore, positioning dosimeters at the center of a section is recommended.

Models, Structural↗
PubMedDate not supplied

Computer-assisted quality assurance for radiographic equipment.

A quality assurance procedure which includes a computer program has been implemented to facilitate measurement of some of the parameters normally tested on diagnostic radiographic equipment. These include: reproducibility of output, linearity of mA settings, filtration, kVp calibration, timer error, SID indication, light field--x-ray field coincidence and effective focal spot size. The user may omit those sections which are not applicable to his needs. Full use is made of the data reducing the number of field measurements needed.

Computers↗