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Biomedical subjects

J E Gray

Publications and source records attributed to J E Gray.

At least 19 recordsLinked to original sources
PubMed1992

Characterization, primary structure, and evolution of lamprey plasma albumin.

The most abundant protein found in blood plasma from the sea lamprey (Petromyzon marinus) has the hallmarks of a plasma albumin: namely, high abundance, solubility in distilled water, a small number of tryptophans, and a high content of cysteines and charged residues. As in other vertebrate albumins, not all the cysteines are disulfide bonded. An unusual feature of this protein is its molecular weight of 175,000, roughly 2.5 times the size of other vertebrate albumins. Its amino acid sequence, deduced from a series of overlapping cDNA clones, can be aligned with other members of the gene family including plasma albumin, alpha-fetoprotein, and vitamin-D binding protein, confirming that it is indeed an oversized albumin. An unusual feature of the sequence is a 28-amino acid stretch consisting of a serine-threonine repeat with the general motif (STTT). Lamprey albumin contains a 23-amino acid putative signal peptide and a 6-residue putative propeptide, which, when cleaved, yield a mature protein of 1,394 amino acids with a calculated molecular weight of 157,000. The sequence also includes nine potential N-linked glycosylation sites (Asn-X-Ser/Thr), consistent with observation that lamprey albumin is a glycoprotein. If all the potential glycosylation sites were occupied by clusters of 2,000 molecular weight each, the total molecular weight would be 175,000. Like other members of the gene family, lamprey albumin is composed of a series of 190-amino acid repeats, there being seven such domains all together. Quantitative amino acid sequence comparisons of lamprey albumin with the other members of the gene family indicate that it diverged from an ancestral albumin prior to the gene duplications leading to this diverse group. This notion is confirmed by the pattern of amino acid insertions and deletions observed in a consideration of all domains that compose this family. Furthermore, it suggests that the invention of albumin antedates the vertebrate radiation.

Amino Acid Sequence↗
PubMed1992

Use of the SMPTE test pattern in picture archiving and communication systems.

In 1985 the Society of Motion Picture and Television Engineers (SMPTE) published a Recommended Practice (RP-133) entitled Specifications for Medical Diagnostic Imaging Test Pattern for Television Monitors and Hard-copy Cameras. Since that time the SMPTE monochrome test pattern has been applied to the acceptance testing and quality control of video and image display systems, and hard-copy (film) recorders. The major features of the test pattern will be discussed along with applications and the problems demonstrated with the pattern. Furthermore, the test pattern will be used to demonstrate that color displays may exhibit only one-half of the resolution of a monochrome monitor whereas the display contrast (due to limited dynamic range) may be only 10 to 20% of that obtained with a monochrome display.

Data Display↗
PubMed1992

Acceptance testing of radiologic systems: experience in testing 129 imaging systems at two major medical facilities.

The problems encountered in acceptance testing of newly installed imaging equipment at two major medical institutions over a 10-year period are presented. Acceptance tests were conducted in 129 newly installed imaging systems with conventional acceptance testing methods. A total of 1,132 problems were documented. Problems were classified as major or minor; there were 772 major problems and 360 minor problems. An average of six major and three minor problems were documented in each new equipment installation tested. In some instances, final payment was withheld for several months or more to ensure correction of the problems identified. This experience confirms the need of thorough acceptance testing of new imaging equipment before final payment is made to the vendor.

Alabama↗
PubMed1992

A comparison of mammography screen-film combinations.

A comparison study was performed to evaluate the image quality and radiation dose of six mammographic screen-film combinations: a Min-R screen with OM-1, SO-155, and SO-177 films (Eastman Kodak); a Min-R medium screen (Eastman Kodak) with OM-1 film; an HR Mammo medium screen (Fuji Medical Systems USA) with OM-1 film; and a Min-R fast screen with T-Mat M II film (Eastman Kodak). SO-177 films were processed with an extended cycle. Exposures of an acrylic test object with embedded masses, fibers, and specks and of a preserved breast specimen were made, for two paired image comparison tests in which the visibility of diagnostic features, contrast, and noise were judged. In most areas of image quality evaluated, a Min-R screen with OM-1, SO-155, and SO-177 films was superior. These three screen-film combinations had similar imaging characteristics, even though OM-1 film requires a higher radiation exposure. Images produced with a Min-R fast screen and T-Mat M II film were significantly lower in quality.

Breast Neoplasms↗
PubMed1992

Neonatal therapeutic intervention scoring system: a therapy-based severity-of-illness index.

Severity-of-illness scales have proven valuable in assessing clinical outcomes and resource consumption in adult and pediatric intensive care, but they have been less extensively developed for neonatal care. The National Therapeutic Intervention Scoring System (NTISS) was created by modifying the Therapeutic Intervention Scoring System (TISS). From the 76 original TISS items, 42 were deleted and 28 added to form the NTISS. Like TISS, NTISS assigns score points from 1 to 4 for various intensive care therapies. Admission-day NTISS scores were calculated for 1643 newborns admitted to three neonatal intensive care units (NICUs) between November 1, 1989, and September 30, 1990. NTISS scores ranged from 0 to 47 with a mean of 12.3 +/- 8.7 (SD). There was little correlation with birth weight (r = -.11) or gestational age (r = -.17), but NTISS scores were highly correlated with expected markers of illness severity, including mortality risk estimates by neonatal attending physicians (r = .70, P < .0001), in-hospital mortality rates (P < .05), and a measure of nursing acuity (Medicus) (r = .69, P < .0001). In addition, admission-day NTISS scores were found to be predictive of both NICU length of stay (r = .37, P < .0001) and total hospital charges for survivors (r = .65, P < .0001). It is concluded that NTISS is a valid measure of therapeutic intensity that is independent of birth weight and can be used as an indicator of neonatal illness severity and resource utilization. Further validation in other NICUs is required.

Hospitalization↗
PubMed1991

Technical exhibits.

Explore the source record for details and available documents.

Exhibitions as Topic↗
PubMed1991

Sensitometric responses of selected medical radiographic films.

Radiographic films produce different densities and contrast when processor changes occur, and the magnitude and rate of change vary with film type. The ability to detect and interpret the clinical importance of film density changes may depend on the method of sensitometry used. The characteristics of several medical radiographic films and various sensitometers were examined under three sensitometric variations and five processing variations. Of all variations used, only exposure with a single-versus a double-sided sensitometer caused a film type to have a marked different response. The results indicate that mismatching the sensitometer spectral output with the spectral sensitivity of the film in most cases does not affect the density changes of the film. The fact that a few films may be sensitive to differences in spectral content of the exposing light and dual- versus single-sided exposure and that only a limited number of film types were tested, however, leads to the prudent conclusion that the exposure conditions for quality control purposes should match clinical exposure conditions as closely as possible.

Technology, Radiologic↗
PubMed1990

Self-incompatibility: a self-recognition system in plants.

Self-incompatibility (SI), a genetically controlled mechanism to prevent inbreeding in plants, offers a relatively simple model system for studying the interactions between plant cells or between a plant cell and the secreted product or products of another cell. Examples of two major types of SI, gametophytic and sporophytic, have been studied by cloning cDNAs corresponding to glycoproteins of the female tissues that segregate with particular variants encoded by the putative S locus. These secreted glycoproteins are envisaged to interact with the currently undescribed pollen component to cause arrest of pollen tube growth.

Amino Acid Sequence↗
PubMed1990

Isn't it time to abandon cine film?

Cine has served our needs well since the early 1950s. For the first time, it allowed recording of motion studies of the cardiac structures on film. The cine technique has been standardized over the years, both the camera and the display. Cine filming techniques, however, have not advanced, except for new film products with faster emulsions and better-quality films. Video electronic imaging has made rapid advancements. These were prompted by the broadcast industry when the requirements for color were developed in the 1960s and by the advent of new recording techniques that provided a very stable video time base from analog tape recorders. The medical field has been able to capitalize on these developments and to produce some of our own that have not been applied in the broadcast world. These include pulsed progressive 525-line video acquisition of cardiac images in the cardiac catheterization laboratory. We also have been able to capitalize on the improved detector technology that the broadcast world has developed, such as the plumbicon pickup tubes, which produce images with very little lag and so provide images with improved resolution. These developments also have enabled us to reduce radiation to both the patient and the laboratory personnel, especially with implementation of the pulsed progressive acquisition, with which the dose has been reduced 50%. With the advent of interventional procedures in the cardiac catheterization laboratory, the need to assess images immediately cannot be fulfilled by cine filming because of the requirement for the processing of the film with its inherent delays. Quantification of cardiac structures is required to assess the outcome of interventional techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Cineangiography↗
PubMed1990

Inheritance and effect on ripening of antisense polygalacturonase genes in transgenic tomatoes.

The role of the cell wall hydrolase polygalacturonase (PG) during fruit ripening was investigated using novel mutant tomato lines in which expression of the PG gene has been down regulated by antisense RNA. Tomato plants were transformed with chimaeric genes designed to express anti-PG RNA constitutively. Thirteen transformed lines were obtained of which five were analysed in detail. All contained a single PG antisense gene, the expression of which led to a reduction in PG enzyme activity in ripe fruit to between 5% and 50% that of normal. One line, GR16, showed a reduction to 10% of normal PG activity. The reduction in activity segregated with the PG antisense gene in selfed progeny of GR16. Plants homozygous for the antisense gene showed a reduction of PG enzyme expression of greater than 99%. The PG antisense gene was inherited stably through two generations. In tomato fruit with a residual 1% PG enzyme activity pectin depolymerisation was inhibited, indicating that PG is involved in pectin degradation in vivo. Other ripening parameters, such as ethylene production, lycopene accumulation, polyuronide solubilisation, and invertase activity, together with pectinesterase activity were not affected by the expression of the antisense gene.

Food Technology↗
PubMed1990

Hepatic changes produced by 30-day administration of a novel aminocyclitol antibiotic, trospectomycin sulfate, to laboratory animals.

The studies described here were done to characterize the hepatic response to a new aminocyclitol antibiotic, trospectomycin sulfate, administered intravenously (beagle dog) or subcutaneously (Sprague-Dawley rat) at a variety of dose levels, to investigate reversibility of observed changes, and to document any untoward effects of subchronic trospectomycin sulfate administration. Both species showed significant elevations in serum levels of alanine and aspartate transaminases in higher dose groups. In the dog only, a transient neuromuscular blockade was also observed within higher dose groups. No other functional, morphological, or serum chemical changes were observed. Examination of liver by electron microscopy revealed the presence of cytoplasmic lamellar inclusion bodies, concentrated in the bile canalicular region of the hepatocytes. Occurrence of the lamellar bodies and coincident transaminase increases were found to be reversible upon discontinuance of treatment (studied in the dog). Electron microscopy of acid phosphatase cytochemistry in the rat indicated that most, but not all, of the lamellar bodies contained this enzyme. This observation suggests that they may be derived from the lysosome, or once formed become lysosomal.

Acid Phosphatase↗
PubMed1990

Effect of pulsed progressive fluoroscopy on reduction of radiation dose in the cardiac catheterization laboratory.

The increased application of therapeutic interventional cardiology procedures is associated with increased radiation exposure to physicians, patients and technical personnel. New advances in imaging techniques have the potential for reducing radiation exposure. A progressive scanning video system with a standard vascular phantom has been shown to decrease entrance radiation exposure. The effect of this system on reducing actual radiation exposure to physicians and technicians was assessed from 1984 through 1987. During this time, progressive fluoroscopy was added sequentially to all four adult catheterization laboratories; no changes in shielding procedures were made. During this time, the case load per physician increased by 63% and the number of percutaneous transluminal coronary angioplasty procedures (a high radiation procedure) increased by 244%. Despite these increases in both case load and higher radiation procedures, the average radiation exposure per physician declined by 37%. During the same time, the radiation exposure for technicians decreased by 35%. Pulsed progressive fluoroscopy is effective for reducing radiation exposure to catheterization laboratory physicians and technical staff.

Angioplasty, Balloon, Coronary↗