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Biomedical subjects

K W Taylor

Publications and source records attributed to K W Taylor.

At least 55 records · Page 3Linked to original sources
PubMed1981

Bilateral skin conductance, finger pulse volume, and EEG orienting response to tones of differing intensities in chronic schizophrenics and controls.

Skin conductance (SCOR), finger pulse volume (FPV-OR), and EEG orienting responses were examined to repeated tones of either 60- or 90-dB intensity in chronic schizophrenics, nonschizophrenic psychiatric patients, and normals. SCOR reaffirmed previous findings with schizophrenics displaying significantly more frequent nonresponsiveness to 60-dB tones, and faster habituation among patients who did respond. Increased stimulus intensity decreased the incidence of nonresponsiveness to the level of controls, but did not alter the rapid habituation of schizophrenics. These results generalized fully to the FPV-OR, despite the independence demonstrated between SCOR and FPV-OR, but did not generalize to EEG response. There were no significant differences between schizophrenics and controls in EEG reactivity-only in background activity, particularly in a slowing of dominant alpha frequency in schizophrenics. Schizophrenics displayed the same degree of bilateral asymmetry as controls in both SCOR and EEG; there was no evidence of a specifically schizophrenic asymmetry. Schizophrenics nonresponsive in either SCOR or FPV-OR showed significantly greater Conceptual Disorganization and Emotional Withdrawal, and significantly less Excitement than responders in blind clinical ratings on the Brief Psychiatric Rating Scale. None of the findings could be attributed to the effect of neuroleptics. Comparisons between medicated and nonmedicated patients showed no drug-associated effect on any OR variable under study. Drug effects were apparent only in skin conductance level (SCL). Neuroleptics were associated with a significant reduction in SCL in both schizophrenics and nonschizophrenics, together with a flattening of an otherwise incrementing SCL among schizophrenics.

Acoustic Stimulation↗
PubMed1980

Direct effects of rat growth hormone in rat islets of langerhans in tissues culture.

The effects of rat growth hormone (1 microgram/ml) on the synthesis and release of insulin by isolated rat islets of Langerhans were studied. There was no effect of growth hormone on the release of insulin from freshly isolated islets during 30 min incubation periods. By contrast, islets previously cultured for 16h with growth hormone exhibited at 40% increase in the release of insulin in response to glucose or to glucose and theophylline. These islets also showed specific increases in basal and glucose-stimulated insulin synthesis of 16% and 21% respectively, together with a 22% increase in the basal rate of total protein synthesis. The total insulin content of islets was not affected by culture with growth hormone. The adenylate cyclase activity of islet homogenates was unaffected by the presence of growth hormone during 30 min incubations. When homogenates from islets previously cultured with growth hormone were studied, basal adenylate cyclase activity was unchanged, while fluoride-stimulated adenylate cyclase activity was increased by 37%. It is concluded that growth hormone can directly affect the synthesis and release of insulin in islets of Langerhans, without relation to its metabolic activities in other target organs.

Adenylyl Cyclases↗
PubMed1979

Variations in x-ray exposures to patients.

X-ray exposures to patients were measured in 30 rooms in Toronto hospitals. For a given procedure, the total exposure for a satisfactory examination differed from one room to another by as much as a factor of 30, skin exposures reaching 90 R and more for barium enemas and barium meals. The factors primarily responsible for these large differences in exposure were fluoroscopic exposure rate (0.65-12 R/min) and time 1.5-12 min), kVp and filtration (8:1), choice of screen-film combination (6:1) and attenuation of table tops and phototimers (4:1). The increase by a factor of 5 in exposure of pelvic organs, when using beams directed AP instead of PA, requires that remote-controlled GI machines be used cautiously, particularly on women of childbearing age. It is also important that these machines have tables with low attenuation. The use in some rooms of minimal fluoroscopic exposure rates and 70 mm fluorography at total exposures of less than 5 R shows that radiographic examinations can be made virtually "safe" with modern, properly adjusted equipment.

Barium Sulfate↗
PubMed1978

Proinsulin biosynthesis in broken-cell preparations of islets of Langerhans.

1. Rabbit islets of Langerhans were disrupted by ultrasonic methods and the sonicated preparations were used to study proinsulin biosynthesis. 2. When [3h]leucine is incubated in such preparations, incorporation takes place into proinsulin, as evidenced by characterization on polyacrylamide gels, and by the conversion of this labelled material into insulin, by using trypsin. 3. The labelled proinsulin may also be purified by antiinsulin antibody bound to Sepharose. 4. With the broken-cell preparation it was shown that incorporation of leucine is accelerated by increasing the glucose content of the medium from 2mM to 16mM. However, 16mM-galactose or -sucrose did not stimulate incorporation significantly from basal values. This effect of glucose was abolished by cycloheximide. 5. The significance of these findings in relation to the mechanism of glucose stimulation of proinsulin biosynthesis is discussed.

Animals↗
PubMed1978

Reduction of patient exposure by use of heavy elements as radiation filters in diagnostic radiology.

The effect on patient exposure of x-ray filters made of heavy elements has been studied in excretory urography and lumbar spine examinations. Several elements with atomic numbers between 62 and 74 were tested in experiments using radiographic phantoms and in patient studies. A holmium filter reduced skin exposure by more than 50% in excretory urography. Similar results were obtained with ytterbium and tungsten in lumbar spine studies.

Aluminum↗
PubMed1978

Detection accuracy in chest radiography.

The detection accuracy of the diagnostic radiologist is important in everyday medical decision making. However, little work has been done relating the detection accuracy of the radiologist to the quality of the image. This study, using a thorax and lung phantom, simulated tissue-equivalent 6.4 mm lesions, and a 183 cm source-to-image distance, shows that the detection accuracy is not dependent on the focal spot size (over a range of 0.3-2.0 mm). However, the false positive rate increases when using small focal spots. In addition, the detection accuracy decreases with increasing root-mean-square (RMS) noise (a measure of the amount of quantum mottle in the image), while the false positive rate and intraobserver disagreement increase with increasing RMS noise. It is also shown that the nonradiologist responds to changes in noise in exactly the same way as the radiologist.

Diagnostic Errors↗
PubMed1977

A species difference in nucleoside phosphorylase activity and inosine-stimulated insulin secretion in isolated islets of Langerhans.

Inosine is a potent simulant of insulin release from rat but not from rabbit islets of Langerhans. Further investigation showed that nucleoside phosphorylase activity is exceptionally low in rabbit islets. The ability of inosine to promote insulin release seems to be related to islet nucleoside phosphorylase activity, which can display marked species differences.

Animals↗
PubMed1977

Specification of angulated projections in coronary arteriography.

In coronary arteriography cranial and caudal angulations are combined with oblique angulations to obtain additional views. The angulations are obtained with a variety of equipment rotating about different axes. The planes and axes in and about which the patient and equipment rotate are defined and the equipment is grouped according to the axes about which it rotates. It is shown that a simple definition of the angulation of a projection may be obtained using concepts and terminology consistent with current radiological practice. One group of equipment then gives directly from the rotation of its component parts the angles specifying the projection. For other equipment, the angles specifying the projection are calculated and tabulated for angles of rotation of the equipment from 0 to 90 degrees. Thus, equivalent projections for the different equipment may be found and compared.

Angiography↗