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Biomedical subjects

D C Taylor

Publications and source records attributed to D C Taylor.

At least 91 records · Page 5Linked to original sources
PubMed1994

2. Current noninvasive diagnosis of carotid artery stenosis: indications and limitations.

Noninvasive techniques are widely used to assess patients with cerebrovascular disease. The most common method is duplex ultrasonography, which has an accuracy of approximately 90% in the detection of carotid stenosis. There are many potential limitations to the technique of duplex ultrasonography, but in the hands of experienced technologists and physicians who recognize possible sources of error, it provides excellent clinical accuracy. Transcranial Doppler is complementary to duplex ultrasonography in the assessment of the intracranial circulation. Magnetic resonance angiography shows promise as a noninvasive method of assessing carotid stenosis, but its availability is limited, and this technique is still in the developmental stage.

Carotid Arteries↗
PubMed1993

Aortoiliac occlusive vascular disease in association with congenital pelvic kidney.

Congenital renal ectopia, although a rare entity, creates potential difficulties in the management of patients requiring aortic surgery. An increasing number of vascular patients with renal transplants who have renal ectopia are being encountered as well. Therefore a management plan is desirable. A recent case of aortoiliac occlusive disease associated with congenital pelvic kidney requiring aortobifemoral bypass grafting is described. A brief review of the anatomy, embryology, and management is given.

Aorta, Abdominal↗
PubMed1993

The role of arteriography in assessing vascular injuries associated with dislocations of the knee.

All patients with a diagnosis of knee dislocation during a 7 1/2-year period (1984-1991) were reviewed retrospectively. There were 37 knee dislocations (KDs) in 35 patients. The mechanism of injury was predominantly motor vehicle or pedestrian crashes. Popliteal artery injury was present in 6 of 37 (16%). There was no significant vascular injury in 31 of 37 knee dislocations as evidenced by normal arteriograms or absence of vascular complications on follow-up. Of those with no significant vascular injury, 3 of 31 had limb ischemia that improved with reduction of the KD, had normal arteriograms, and had no further vascular treatment. All patients with popliteal artery injury had a pulse deficit (five of six) or a documented history of ischemia (six of six). In the absence of these findings, no patient was found to have an arterial injury. Arterial injuries were treated with interposition (five of six) or bypass graft (one of six) and fasciotomies (six of six). Amputation was required in one of six of the vascular injury group and none of 31 of the remainder of the patients with no vascular injury. We recommend the selective use of arteriography in patients with KDs based on a history or clinical findings of ischemia and do not recommend routine arteriography for all patients with KD.

Accidents, Traffic↗
PubMed1992

Measurement of lysozyme by an enzyme-linked immunosorbent assay.

In this study an enzyme-linked immunosorbent assay has been developed for the determination of lysozyme in saliva, serum and urine. The assay relies on the detection of specific protein rather than lytic activity, a property which has been shown to be most suitable for the quantitation of lysozyme in mucin containing substances. Our results indicate that no pretreatment is necessary for the immunochemical method. The assay is sensitive to concentrations as low as 1 microgram lysozyme/l. The intra-assay and inter-assay coefficients of variation were 5.9% and 15.8% respectively. The lysozyme level in whole saliva was 55.53 +/- 30.35 mg/l, in serum the level was 0.64 +/- 0.15 mg/l and in urine it was 0.17 +/- 0.22 mg/l. Comparisons between immunochemical determination and lytic assays showed a good correlation (serum, r = 0.79, P less than 0.01; saliva, r = 0.85, P less than 0.005; treated saliva, r = 0.96, P less than 0.001).

Adult↗
PubMed1992

Biosynthesis of storage lipids in plant cell and embryo cultures.

The biosynthesis of storage lipids in plant cell and embryo cultures is discussed in the light of their significance in the breeding of agriculturally important oil seed crops. After a short introduction to the biosynthesis of storage lipids, i.e. triacylglycerols and wax esters, this review covers the occurrence and biosynthesis of storage lipids in plant cell and embryo cultures. Plant cells in culture generally contain low levels of both unusual fatty acids and triacylglycerols indicating that these cells are quite different from cells of oil storage tissues. There are a few exceptions to this rule which demonstrate that induction of genes involved in the expression of fatty acid modification and triacylglycerol assembly is possible in plant cell cultures. Such biosynthetically active plant cells may be of particular interest in future studies of storage lipid assembly. Both somatic and gametophytic embryos of oil plants exhibit high capacities for storage lipid biosynthesis and accumulation in vitro compared to cultured plant cells. Above all, the microspore-derived embryo system is recommended to both plant breeders and plant biochemists for the selection and multiplication of plants of superior quality.

Agriculture↗
PubMed1992

Biotypes of Haemophilus parainfluenzae from the respiratory secretions in chronic bronchitis.

A total of 2401 isolates of Haemophilus parainfluenzae was isolated from respiratory secretions of 36 healthy adults and 128 patients with chronic bronchitis over a period of 1 year. The isolates were allocated to eight biotypes, by their production of indole, urease and ornithine decarboxylase. Biotypes I and II constituted most of the isolates of H. parainfluenzae from the oropharynx of controls (75%) and chronic bronchitics (c. 90%). Among the patients, there was no difference in the isolation rate between oropharyngeal swabs and sputum specimens. Biotypes III, IV, VI, VII and VIII were isolated less frequently, as was a new taxon defined here as biotype V which does not produce indole, urease or ornithine decarboxylase. Biotype III was isolated significantly less frequently from cases of chronic bronchitis than from controls, whereas biotype II was isolated somewhat more frequently from the patients, especially during acute episodes.

Adult↗
PubMed1992

Biosynthesis of Acyl Lipids Containing Very-Long Chain Fatty Acids in Microspore-Derived and Zygotic Embryos of Brassica napus L. cv Reston.

Biosynthesis of very long chain (>C(18)) fatty acids (VLCFAs) and the pathway for their incorporation into acyl lipids was studied in microspore-derived (MD) and zygotic embryos of Brassica napus L. cv Reston. In the presence of [1-(14)C]oleoyl-coenzyme A or [1-(14)C] eicosenoyl-coenzyme A, malonyl-coenzyme A, and reducing equivalents, maximal in vitro elongation activity was expressed in protein preparations from early-mid cotyledonary stage MD embryos (17-20 days in culture), when endogenous eicosenoic (20:1) and erucic (22:1) acids were just beginning to accumulate (approximately 1.5 milligrams per gram dry weight). The biosynthesis of VLCFAs and their incorporation into glycerolipids in vitro in the MD embryo system occurred at rates comparable to those measured in developing zygotic Reston embryos at about 20 days postanthesis. When glycerol-3-phosphate was supplied as acyl acceptor in time-course experiments using homogenates prepared from 18-day MD embryos, newly synthesized [(14)C]20:1 and [(14)C]22:1 were incorporated primarily into triacylglycerols (TAGs) and, to a lesser extent, into lyso-phosphatidic/phosphatidic acids, diacylglycerols, and phosphatidylcholines as well as the acyl-coenzyme A and free fatty acid pools. [(14)C]24:1 was not detected in any acyl lipid. Stereospecific analyses of the radiolabeled TAGs indicated that [(14)C]20:1 and [(14)C]22:1 moieties were esterified predominantly at the sn-3 position, but were also found at the sn-1 position. [(14)C]20:1, but not [(14)C]22:1, was detected at the sn-2 position. Similar patterns of (14)C-labeled VLCFA distribution were obtained in experiments conducted using a 15,000g pellet fraction from 18-day MD embryos. All trends observed in the formation of TAGs containing VLCFAs in the Reston MD embryo system were also confirmed in studies of zygotic embryos of the same cultivar. The data support the biosynthesis of 20:1 and then 22:1 via successive condensations of malonyl-coenzyme A with oleoyl-coenzyme A and, for the first time in B. napus, demonstrate the incorporation of newly synthesized VLCFAs into TAGs via the Kennedy pathway.

Journal Article↗
PubMed1992

Evaluation of the operating room as a surgical teaching venue.

Surgical educators are facing changes in residency training that have a direct impact on the opportunity that surgeons and residents have for clinical teaching and learning. The knowledge required of residents continues to escalate. Further, as resident positions are reduced, the opportunity for inter-resident education is decreased. Increased service-to-education ratios may result in resident discontent unless surgeons take an active role in the resident's educational experience. The purpose of this study was to examine the educational activities that occur during the operating-room experience. Technical training in the procedure being done was the primary educational activity, but there were long periods when no form of education was taking place. The operating room provides the teacher and learner with uninterrupted time together, and this time can and should be used for clinical teaching and learning.

General Surgery↗
PubMed1992

Prevention of vascular injuries in revision total hip replacement.

Iliac-vessel injury from total hip arthroplasty is associated with hemorrhagic complications and an increased death rate. The authors identified seven patients who had severe medial displacement of the acetabular prosthesis and associated vascular injury to the iliac vessels after total hip replacement. One patient had two hip replacements. Preoperative findings included a pelvic mass (three hips), pelvic pain (eight), radiologic evidence of cement in the pelvis (three) and the acetabular prosthesis in the pelvis (eight), computed tomographic evidence of cement in the pelvis and proximity of the prosthesis to the iliac vessels (four), and arteriography showing displacement or compression of the iliac vessels (seven). Operative management in all cases involved medial exposure, mobilization and repair of the iliac vessels before revision of the hip prosthesis. Postoperative complications were deep vein thrombosis (three), in spite of prophylaxis, and occlusion of a vein interposition graft (one) requiring placement of a femoral crossover graft. There were no deaths, amputations or hemorrhagic complications. The authors advocate preoperative identification of patients who have iliac-vessel involvement by their total hip prosthesis and initial medial extraperitoneal exposure and repair of these vessels before removal of the displaced acetabular prosthesis.

Angiography↗
PubMed1991

Aortic pseudoaneurysm secondary to celiac plexus block.

Traumatic pseudoaneurysm of the abdominal aorta has been infrequently reported in the literature. We report a case of an infected pseudoaneurysm of the supraceliac aorta which we believe to be secondary to celiac plexus block performed for pain from chronic pancreatitis. The aneurysm was successfully repaired using a Dacron graft through a thoracoabdominal approach. The possible mechanism of aortic injury from celiac plexus block is discussed.

Aneurysm↗
PubMed1991

Steric stabilization of microspheres with grafted polyethylene oxide reduces phagocytosis by rat Kupffer cells in vitro.

Sterically stabilized polyethylene oxide-polystyrene copolymer microspheres, (PS-PEO) and charge stabilized polystyrene (PS) microspheres of similar size (1 micron) were prepared in order to compare their uptake by cultured rat Kupffer cells isolated by centrifugal elutriation. The uptake of the sterically stabilized particles was found to be much less than that for the charge stabilized control. The uptake of microspheres stabilized with covalently grafted PEO was lower or equivalent to that of control microspheres stabilized by the adsorption of the non-ionic PEO-polypropylene oxide (PPO-PEO) surfactant Poloxamer 238 or Methoxy-PEO. Phagocytic uptake by Kupffer cells at low and body temperature (8 degrees C and 37 degrees C) demonstrated that PS-PEO particles showed both low adherence and low metabolic uptake. The adsorption of PEO, as Poloxamer 238, to particles with covalently attached or grafted PEO resulted in a synergistic reduction in uptake that was greater than the individual effects of grafting and adsorption alone (P less than or equal to 0.001). It is suggested that this combination produces a more effective steric barrier on the particle surface with the Poloxamer adsorbing to the surface between the grafted PEO chains. The relevance to drug targeting/carrier systems is discussed.

Adsorption↗
PubMed1991

Psychophysiological anomalies in children with emotional and conduct disorders.

We studied patterns of psychophysiological (skin conductance, heart rate) reactivity to sounds and to situations with varying emotional and alerting connotations in child psychiatric outpatients and in healthy controls. Children with emotional disorders were particularly reactive to situations with aversive components, while conduct disorder subjects showed increased reactivity to pleasant situations and decreased responses to neutral but high-intensity stimulation and to withdrawal of stimulation in silence periods. The results indicate patterns of biological reactivity which may underlie different psychiatric disturbances in children.

Adolescent↗
PubMed1991

Duplex ultrasound in the assessment of vascular disease in clinical hypertension.

Duplex ultrasound combines B-mode imaging and pulsed Doppler flow analysis and is rapidly becoming the most useful and widely applied method for the evaluation of atherosclerotic arterial disease. Recent technical improvements including color flow Doppler allow its application to practically all vascular beds in the body. Duplex is noninvasive and in many areas its accuracy in the detection of arterial stenosis and occlusion rivals angiography. Duplex ultrasound has become the preferred method of evaluation of patients with cerebrovascular disease. It provides information about the degree of stenosis, location of disease, and plaque characterization, and in many cases replaces standard cerebral arteriography. Duplex ultrasound has been used to detect renal artery stenosis in patients suspected of having renovascular hypertension with an accuracy of 93% in the diagnosis of hemodynamically significant stenosis. It also has important applications in the assessment of mesenteric artery stenosis, peripheral vascular disease, and venous disease. Because it is accurate, reasonably inexpensive, and noninvasive, duplex ultrasound can be used to follow the progression of untreated atherosclerotic lesions throughout the body. Used in this fashion, it provides important information about the natural history of atherosclerotic lesions, their clinical prognosis, and the effect of interventions, either medical or surgical, on lesions.

Cardiovascular Diseases↗
PubMed1991

Triacylglycerol Bioassembly in Microspore-Derived Embryos of Brassica napus L. cv Reston.

Erucic acid (22:1) was chosen as a marker to study triacylglycerol (TAG) biosynthesis in a Brassica napus L. cv Reston microspore-derived (MD) embryo culture system. TAGs accumulating during embryo development exhibited changes in acyl composition similar to those observed in developing zygotic embryos of the same cv, particularly with respect to erucic and eicosenoic acids. However, MD embryos showed a much higher rate of incorporation of (14)C-erucoyl moieties into TAGs in vitro than zygotic embryos. Homogenates of early-late cotyledonary stage MD embryos (14-29 days in culture) were assessed for the ability to incorporate 22:1 and 18:1 (oleoyl) moieties into glycerolipids. In the presence of [1-(14)C]22:1-coenzyme A (CoA) and various acyl acceptors, including glycerol-3-phosphate (G-3-P), radiolabeled erucoyl moieties were rapidly incorporated into the TAG fraction, but virtually excluded from other Kennedy Pathway intermediates as well as complex polar lipids. This pattern of erucoyl incorporation was unchanged during time course experiments or upon incubation of homogenates with chemicals known to inhibit Kennedy Pathway enzymes. In marked contrast, parallel experiments conducted using [1-(14)C]18:1-CoA and G-3-P indicated that (14)C oleoyl moieties were incorporated into lyso-phosphatidic acids, phosphatidic acids, diacylglycerols, and TAGs of the Kennedy Pathway, as well as other complex polar lipids, such as phosphatidylcholines and phosphatidylethanolamines. When supplied with l-[2-(3)H(N)]G-3-P and [1-(14)C]22:1-CoA, the radiolabeled TAG pool contained both isotopes, indicating G-3-P to be a true acceptor of erucoyl moieties. Radio-high-performance liquid chromatography, argentation thin-layer chromatography/gas chromatography-mass spectrometry, and stereospecific analyses of radiolabeled TAGs indicated that 22:1 was selectively incorporated into the sn-3 position by a highly active diacylglycerol acyltransferase (DGAT; EC 2.3.1.20), while oleoyl moieties were inserted into the sn-1 and sn-2 positions. In the presence of sn-1,2-dierucin and [1-(14)C]22:1-CoA, homogenates and microsomal preparations were able to produce radiolabeled trierucin, a TAG not found endogenously in this species. A 105,000g pellet fraction contained 22:1-CoA:DGAT exhibiting the highest specific activity. The rate of 22:1-CoA:DGAT activity in vitro could more than account for the maximal rate of TAG biosynthesis observed in vivo during embryo development. In double label experiments, G-3-P was shown to stimulate the conversion of [(3)H]phosphatidylcholines to [(3)H]diacylglycerols, which subsequently acted as acceptors for (14)C erucoyl moieties. In vitro, 22:1 moieties did not enter the sn-1 position of TAGs by a postsynthetic modification or transacylation of preformed TAGs.

Journal Article↗
PubMed1991

Psychological disturbance and its associations in the children of the Gujarati community.

The infrequent referral of Asian children to child psychiatry clinics was noted. By administering Rutter's scale A2 to samples of Gujarati and English parents with children between the ages of 4 and 7 years a lower rate of disturbance was demonstrated among the Asian sample providing an explanation for the original observation. Family and child-rearing factors associated with disturbance were identified.

Affective Symptoms↗