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Biomedical subjects

D C Taylor

Publications and source records attributed to D C Taylor.

At least 55 records · Page 3Linked to original sources
PubMed1997

Arthroscopic treatment of soft-tissue impingement of the ankle in athletes.

Sixty ankle arthroscopies were performed on patients with chronic soft-tissue impingement of the ankle after an ankle sprain between January 1989 and January 1994. Preoperative examination findings featured tenderness localized to the anterolateral aspect of the ankle, no instability, and, with the exception of 2 patients, normal radiographs. A preoperative bone scan was performed on 34 patients and was positive in each case but was not specific. Arthroscopy was performed an average of 23 months after injury. Results were determined by using a new ankle rating score. Hypertrophic synovium, synovitis, or fibrous adhesions were arthroscopically visualized and resected in all cases. The average follow-up was 27 months (range, 6 to 64 months). Thirty-one patients underwent complete evaluation and 29 were evaluated over the telephone. There were 51 excellent, 7 good, 1 fair, and 1 poor results. The diagnosis of chronic soft-tissue impingement of the ankle can be made from an appropriate history, thorough physical examination, and plain radiographs. Ankle arthroscopy with resection of impinging hypertrophic synovium or fibrous bands occurring after an ankle sprain was effective in alleviating pain in athletes.

Adult↗
PubMed1997

Surgical treatment of severe autistic regression in childhood epilepsy.

We report 2 children with partial epilepsy who manifested social and language regression and partial recovery after surgical treatment. One child had seizures since the first 2 weeks of life, caused by a right temporal dysembryoplastic neuroepithelial tumor and regression in the latter part of the first year; seizures were relieved and some functions were recovered after temporal lobe resection at 12 months of age. The second child developed epilepsy at 3 years 3 months, and between 5 years 9 months and 6 years 1 month he became aphasic (Landau-Kleffner syndrome) and lost social functioning, manifesting a very severe behavior disorder. He exhibited a significant improvement in communication, social functioning, and behavior after left multiple subpial transections. Both children manifested evidence of subclinical seizure activity in both temporal lobes. Their clinical picture was one of combined language and autistic regression, and the autistic features demonstrated a clear response to surgical treatment. We suggest that in pediatric epilepsy surgical programs, autistic regression should prompt urgent investigation if drug treatment is not effective.

Autistic Disorder↗
PubMed1997

Progress in abdominal aortic aneurysm surgery: four decades of experience at a teaching center.

The purpose of this study was to examine the changing trends in surgical management of patients with abdominal aortic aneurysms at a tertiary care teaching hospital over the past 40 years, by analysis of demographic data, perioperative variables and outcomes on all patients having abdominal aortic aneurysm surgery between 1955 and 1993. Some 1604 abdominal aortic aneurysms were assessed. The annual rate of abdominal aortic aneurysm surgery increased from 17.6 to 67.8 cases per year. The non-ruptured to ruptured abdominal aortic aneurysm ratio increased from 2.4:1 in the first decade to 3.4:1 in the last 5 years. In non-ruptured abdominal aortic aneurysm repairs, the following variables changed over the four decades: patients age over 80 years increased (2.4% to 8.0%; P<0.04), concomitant lower-limb occlusive disease increased (12.2% to 23.7%; P<0.02), prevalence of smaller aneurysms (4-6 cm) increased (16.0% to 54.2%; P<0.0001); intraoperative hypotension decreased (9.0% to 0.7%; P<0.0001), postoperative hemorrhage decreased (8.2% to 0.0%, P<0.0001), postoperative leg ischemia decreased (5.7% to 1.1%; P<0.02) and postoperative amputation rate decreased (3.2% to 0.0%; P<0.03). There was a significant decrease in perioperative mortality (17.0% to 3.4%; P<0.0001). For ruptured aneurysms, early operation (within 1 h of admission) increased from 8.7% to 55.8% (P<0.0001), prevalence of intraoperative hypotension decreased (50.0% to 23.5%; P<0.001), and major venous injury decreased (18.0% to 5.2%; P<0.05). Mortality, however, did not decrease significantly (54.2% to 44.2%; P=0.32). In conclusion, there was a significant decrease in mortality and morbidity associated with non-ruptured abdominal aortic aneurysm repair over the four decades studied. In addition, older patients with smaller aneurysms and more co-morbid conditions were operated on during this period. Mortality for patients operated on for ruptured abdominal aortic aneurysm repair has not changed significantly.

Adult↗
PubMed1997

Selective shunting with EEG monitoring is safer than routine shunting for carotid endarterectomy.

The purpose of this study was to identify whether EEG is an adequate method of monitoring cerebral perfusion during carotid endarterectomy and of determining the need for use of an indwelling shunt. A retrospective review of 305 carotid endarterectomies comparing the results of routinely shunted patients with patients selectively shunted based on EEG monitoring, was carried out. Of the carotid endarterectomies, 92 (30%) were routinely shunted and 213 (70%) were selectively shunted. In the selectively shunted group, 34 (16%) subsequently required shunting. The major stroke rate in the routinely shunted group was 4.4% ((4) cases) and in the selectively shunted group was 0.5% ((1) stroke). Three of the four major strokes in the routinely shunted group were embolic in origin and one was caused by acute thrombosis. The only major stroke in the selectively shunted group was from intracerebral hemorrhage. In conclusion EEG monitoring is a safe and reliable method to determine the need for shunting during carotid endarterectomy. Routine non-selective use of a shunt may increase the risk of perioperative stroke from arterial injury and associated thromboembolism.

Aged↗
PubMed1997

Interacting RNA species identified by combinatorial selection.

RNA molecules were selected from a random sequence library for their ability to bind to an RNA stem-loop target. Oligonucleotides with extensive Watson-Crick complementarity to the RNA ligand were selected against by inclusion of a blocking oligodeoxynucleotide in the binding phase of the selection protocol. After 18 generations of SELEX (systematic evolution of ligands by exponential enrichment) a single RNA family was predominant in the binding population. The winning aptamer RNA bound the target RNA with an apparent Kd = 70 nM. Structural mapping and Fe(II)-EDTA protection indicated that the target RNA interacted with small unpaired loops in the aptamer structure.

Base Composition↗
PubMed1997

Can duplex ultrasonography select appropriate patients for carotid endarterectomy?

OBJECTIVES: This study investigated the reliability of carotid duplex ultrasound (DUS) to identify appropriate candidates for carotid endarterectomy (CEA) according to a panel of vascular specialists. DESIGN: Prospective study. MATERIAL: 102 patients with 145 carotid bifurcation stenosis or occlusions. METHODS: All patients who required a carotid angiogram were evaluated using DUS followed by carotid angiography. A blinded panel of four vascular specialists individually decided whether CEA would be appropriate for each patient based on pre-angiographic information. Angiograms were then shown to panelists to see if their management decision was altered by the angiogram. RESULTS: For stenosis > or = 80% on DUS (n = 60), panelists unanimously agreed on CEA without angiography in 57 lesions. In 50 lesions (87.7%), angiography showed > or = 70% stenosis and the management plan remained unchanged. For the other seven lesions, intracranial aneurysms (n = 2), tandem intracranial lesion (n = 1), unsuspected proximal common carotid lesion (n = 1), a 40% stenotic lesion (n = 1), and high carotid bifurcations (n = 2) were seen. In lesions with 50-79% stenosis on DUS (n = 66), none of the panelists recommended CEA without prior angiography. Eighteen (27%) of these lesions were > or = 70% stenosed on angiogram. Complications of angiograms included one stroke, one haematoma, and one severe allergic reaction. CONCLUSION: Carotid duplex ultrasonography without angiography can reliably select lesions appropriate for surgery only when critical stenosis > or = 80% is chosen. Routine angiography is recommended for carotid stenosis of 50-79% when CEA is considered.

Carotid Stenosis↗
PubMed1997

Skin dose from radionuclide contamination on clothing.

Skin dose due to radionuclide contamination on clothing is calculated by Monte Carlo simulation of electron and photon radiation transport. Contamination due to a hot particle on some selected clothing geometries of cotton garment is simulated. The effect of backscattering in the surrounding air is taken into account. For each combination of source-clothing geometry, the dose distribution function in the skin, including the dose at tissue depths of 7 mg cm(-2) and 1,000 mg cm(-2), is calculated by simulating monoenergetic photon and electron sources. Skin dose due to contamination by a radionuclide is then determined by proper weighting of the monoenergetic dose distribution functions. The results are compared with the VARSKIN point-kernel code for some radionuclides, indicating that the latter code tends to underestimate the dose for gamma and high energy beta sources while it overestimates skin dose for low energy beta sources.

Beta Particles↗
PubMed1997

Viscoelastic characteristics of muscle: passive stretching versus muscular contractions.

This study compared the effects of repeated contractions and repeated passive stretches on the viscoelastic properties of muscle. The tibialis anterior (TA) muscles of eight anesthetized male New Zealand white rabbits were studied. In each rabbit, one hindlimb was randomly assigned to the repeated muscular contraction group (CON) and the contralateral hindlimb to the repeated passive stretch group (STRETCH). The passive tension at neutral length was measured in all muscles before and after both repeated muscular contractions or repeated passive stretches. In the CON hindlimb, the peroneal nerve was stimulated with a nerve stimulator for 1 s, and the resulting contractile force was measured. Stimulations were repeated every 10 s for a total of 10 contractions. In the STRETCH hindlimb, the TA was stretched from its shortest in vivo length to its maximum in vivo length 10 times at 20 cm x min-1. The maximum force generated during the first contraction in the CON group averaged 21.74 +/- 1.41 N, with a subsequent reduction with each muscle contraction to 13.66 +/- 0.81 N by the tenth contraction. The average peak tensile force in the STRETCH group was 17.39 +/- 2.61 N for the first passive stretch, decreasing to 13.57 +/- 1.84 by the tenth stretch. After repeated muscular contractions in the CON hindlimbs, the passive tension at neutral length decreased from 0.88 +/- 0.22 N to 0.42 +/- 0.08 N. After repeated passive stretches in the STRETCH hindlimbs, the passive tension at neutral length decreased from 1.16 +/- 0.17 N to 0.67 +/- 0.09 N. The percentage decreases in passive tension between the CON and STRETCH groups were not statistically significant (P = 0.24). The results show that stretching and contracting both result in tissue relaxation of the muscle-tendon unit. This finding may be a result of changes in the viscous elements of the connective tissue secondary to the forces generated by either stretches or contractions. This study suggests that well controlled isometric muscular contractions may result in decreased passive tension in a muscle at neutral length, a finding that one normally associates with passive stretching.

Animals↗
PubMed1997

Modification of seed oil content and acyl composition in the brassicaceae by expression of a yeast sn-2 acyltransferase gene.

A putative yeast sn-2 acyltransferase gene (SLC1-1), reportedly a variant acyltransferase that suppresses a genetic defect in sphingolipid long-chain base biosynthesis, has been expressed in a yeast SLC deletion strain. The SLC1-1 gene product was shown in vitro to encode an sn-2 acyltransferase capable of acylating sn-1 oleoyl-lysophosphatidic acid, using a range of acyl-CoA thioesters, including 18:1-, 22:1-, and 24:0-CoAs. The SLC1-1 gene was introduced into Arabidopsis and a high erucic acid-containing Brassica napus cv Hero under the control of a constitutive (tandem cauliflower mosaic virus 35S) promoter. The resulting transgenic plants showed substantial increases of 8 to 48% in seed oil content (expressed on the basis of seed dry weight) and increases in both overall proportions and amounts of very-long-chain fatty acids in seed triacylglycerols (TAGs). Furthermore, the proportion of very-long-chain fatty acids found at the sn-2 position of TAGs was increased, and homogenates prepared from developing seeds of transformed plants exhibited elevated lysophosphatidic acid acyltransferase (EC 2.3.1.51) activity. Thus, the yeast sn-2 acyltransferase has been shown to encode a protein that can exhibit lysophosphatidic acid acyltransferase activity and that can be used to change total fatty acid content and composition as well as to alter the stereospecific acyl distribution of fatty acids in seed TAGs.

1-Acylglycerol-3-Phosphate O-Acyltransferase↗
PubMed1997

End range eccentric antagonist/concentric agonist strength ratios: a new perspective in shoulder strength assessment.

The dynamic muscle stabilizers of the shoulder are critical to high performance in the overhead athlete. Previous evaluations of shoulder strength have focused on the concentric strength of the rotator cuff. Functionally, the rotator cuff muscles interact in an eccentric/concentric fashion. This is the first study to evaluate the end range eccentric antagonist/concentric agonist ratios of the shoulder rotators. Seventy-five asymptomatic college-level males were tested through a range of 20 degrees of lateral rotation to 90 degrees of medial rotation using the Kin-Com computer-assisted, hydraulic-resisted, isokinetic dynamometer at a speed of 90 degrees/sec. The end range (60-90 degrees) ratios for the medial rotators functioning eccentrically and lateral rotators functioning concentrically were 2.39:1 and 2.15:1 for the dominant and nondominant shoulders, respectively. End range (10 degrees of lateral rotation-20 degrees of medial rotation) ratios for lateral rotators functioning eccentrically and medial rotators functioning concentrically were 1.08:1 and 1.05:1 for the dominant and nondominant shoulders, respectively. The application of this functional assessment of strength testing results may provide important information in the evaluation of the injured shoulder in the overhead athlete, for prescreening, and to gauge return to sports after injury or surgery.

Adolescent↗
PubMed1996

Effects of postmortem freezing on tensile failure properties of rabbit extensor digitorum longus muscle tendon complex.

The tensile failures of extensor digitorum longus muscle tendon units from 16 male New Zealand White rabbits were studied in the fresh state (less than 30 minutes after death) and in the frozen/thawed state (frozen at -80 degrees C for 28 days and then warmed to 38 degrees C). Frozen/thawed extensor digitorum longus muscle tendon units had significantly lower values for load to failure (p < 0.01), energy absorbed to failure (p < 0.01), and strain at failure (p < 0.01), and they tended to fail at a different anatomic location (p < 0.01) (broadly at the fascia-muscle interface as compared with horizontally at the musculotendinous junction) than fresh units. The results of this study suggest that freezing muscle tendon units significantly alters their tensile failure characteristics.

Animals↗
PubMed1996

Cloning of a cDNA encoding the 21.2 kDa oleosin isoform from Arabidopsis thaliana and a study of its expression in a mutant defective in diacylglycerol acyltransferase activity.

A full-length cDNA clone (pA23) of 832 bp encoding an oleosin from Arabidopsis thaliana was isolated by differential screening of a silique-specific cDNA library with probes prepared from poly(A)+ RNA isolated from developing seeds of wild-type (WT) Arabidopsis and from mutant AS11 with a lesion affecting diacylglycerol acyltransferase (DGAT) activity during embryo development. The encoded protein has a calculated molecular mass of 21.2 kDa, and its amino acid sequence shows strong sequence homology and structural similarity to other known oleosins. Transcription of the oleosin gene during seed development was both reduced and delayed in AS11 compared to WT. However, the level of oleosin protein did not appear to be down-regulated during seed development, and at maturity, the overall level of oleosin protein was similar in both WT and AS11. These findings indicate that regulation of oleosin gene expression is part of a highly complex, and co-ordinated expression of storage lipid biosynthesis and related (oleosin) genes during oilseed development.

Acyltransferases↗
PubMed1996

Epileptic akinetic mutism: following temporal lobectomy for Rasmussen's syndrome.

A girl aged 9 years with Rasmussen's encephalitis previously treated by left temporal lobectomy suddenly developed prolonged attacks of extremely rapid respirations associated with poverty of body movements and greatly reduced facial movements with loss of speech. Her comprehension appeared intact and she responded to certain requests. Her eye gaze behaviour suggested a high degree of vigilance. The attacks would last from minutes to hours and were repeated up to a dozen times daily. In the context of the stress generated by the illness and other family problems the attacks had been mistaken for an hysterical elaboration. Their ictal nature was confirmed by EEG/video monitoring. Possible links with other developmental language disorders associated with epilepsy are discussed, including a model of autism.

Akinetic Mutism↗
PubMed1996

Predictors of death in nonruptured and ruptured abdominal aortic aneurysms.

PURPOSE: This study evaluated perioperative variables to predict death in nonruptured and ruptured abdominal aortic aneurysm (AAA) surgery. METHODS: A consecutive review of all patients who underwent AAA surgery from January 1984 to December 1993 was carried out. Perioperative variables were analyzed with univariate and multivariate statistical models to predict mortality rates. RESULTS: Four hundred seventy-eight patients with nonruptured AAAs and 157 patients with ruptured AAAs were studied. In patients with nonruptured AAAs, the mortality rate was 3.8%. Using stepwise logistic regression analysis, independent predictors of death were perioperative myocardial infarction (odds ratio [OR], 5.0; p < 0.01), prolonged postoperative ventilation (OR, 4.0; p < 0.01), history of peripheral vascular disease (OR, 2.9; p < 0.01), preoperative renal dysfunction (OR, 2.7; p < 0.01), and history of congestive heart failure (OR, 2.6; p < 0.03). In patients with ruptured AAAs, the mortality rate was 46%. Analysis of preoperative variables using multivariate stepwise logistic regression found predictors of death to be preoperative unconsciousness (OR, 3.1; p < 0.01), advanced age (OR, 1.9; p < 0.01), and cardiac arrest (OR, 1.8; p < 0.05). In patients who survived the initial surgery for ruptured AAA, a second stepwise logistic regression model found independent predictors for subsequent postoperative death to be coagulation disorder (OR, 7.9; p < 0.01), ischemic colitis (OR, 6.4; p < 0.01), inotropic support beyond 48 hours (OR, 4.8; p < 0.01), delayed transport to operating room (OR, 4.6; p < 0.01), advanced age (OR, 4.4; p < 0.01), perioperative myocardial infarction (OR, 4.0; p < 0.05) and postoperative renal dysfunction (OR, 3.7; p < 0.01). CONCLUSION: Prolonged ventilation, perioperative myocardial infarction, a history of peripheral vascular disease, preoperative renal dysfunction, and a history of congestive heart failure are independent predictors of perioperative death in patients with nonruptured AAAs. For patients with ruptured AAAs, mortality rates can be estimated before surgery using age, level of consciousness, and cardiac arrest. For patients who survive the initial surgery for ruptured AAA, subsequent mortality rates can also be predicted.

Aged↗
PubMed1996

Single versus two-incision arthroscopic anterior cruciate ligament reconstruction.

The purpose of this study was to compare single (endoscopic) versus two-incision arthroscopic anterior cruciate ligament reconstruction using bone-patellar tendon-bone in a population of young athletes. All patients followed a similar postoperative rehabilitation program. The Lysholm knee score, the International Knee Documentation Committee Score, KT-1000 arthrometric measurements, Lachman tests, pivot shift tests, isokinetic and functional testing, and perioperative complications were used to compare the two techniques. Anteroposterior and lateral radiographs were also evaluated and compared. Group I comprised 51 patients who underwent two-incision arthroscopic ACL reconstruction. The average age was 19.8 years, with a range of 18 to 22. The average follow-up in this group was 31 months (range, 24 to 43 months). Group II, the endoscopic group, consisted of 31 patients with an average age of 19.4 years (range, 18 to 22). The average follow-up was 25 months (range, 24 to 31 months). There were no significant differences between the two groups using subjective, objective, and functional criteria. There did appear to be a trend toward a residual pivot glide in the endoscopic group, but this did not achieve statistical significance. Radiographic analysis demonstrated an increased incidence of screw divergence in the endoscopic group. Intraoperative complications were more common with the endoscopic method.

Adult↗
PubMed1996

Interscalene anesthesia for shoulder arthroscopy in a community-sized military hospital.

The first 100 consecutive shoulder arthroscopic procedures performed under interscalene anesthesia at a small community-sized military hospital are the basis of this report. This method of anesthesia was compared with 100 shoulder arthroscopies performed in a previous 2-year time period under general anesthesia. A variety of arthroscopic and subsequent open reconstructive procedures about the shoulder were performed using both techniques. Using the interscalene method, 87 regional blocks were entirely successful. Thirteen patients required conversion to general anesthesia for adequate pain control; however, 4 of these had a complete block in the recovery room and required no postoperative narcotics. Seven patients required supplementation with local anesthetic when an open procedure became necessary. There were no major complications. Minor complications included 5 patients with transient Horner's syndrome, 4 patients who experienced anxiety, which was controlled with sedation, and 3 with nausea or pruritus. Interscalene anesthesia provided excellent intraoperative and postoperative analgesia with low morbidity. On a subsequent questionnaire, all patients with a successful block reported that they were extremely satisfied with their experience. Ten patients who had previous shoulder surgery under general anesthesia preferred the interscalene method. In summary, interscalene anesthesia proved to be an excellent method of anesthesia for shoulder arthroscopy. The technique is reproducible within the resources available in most community-level hospitals.

Adolescent↗