Search PubMed⌕ Search

Biomedical subjects

A Taylor

Publications and source records attributed to A Taylor.

At least 379 records · Page 21Linked to original sources
PubMed1995

Dietary restriction delays cataract and reduces ascorbate levels in Emory mice.

Dietary restriction can effectively extend lifespan and retard many age-related debilities. One hypothesis to explain the beneficial effects of dietary restriction is that it prolongs maintenance of cellular homeostasis by limiting endogenous oxidative stress and preserves oxidative defense mechanisms during aging. Ascorbate, a primary antioxidant, may play a major role in preventing oxidative damage. Ascorbate levels were determined in dietary restricted (R) and control (C) Emory mice, a strain which develops age-related cataract due in part to oxidative damage to lens proteins. Mice which consumed a diet restricted by 40% in calories had lower ascorbate concentrations in plasma, liver and kidney. Nevertheless, R animals showed significantly delayed progression of cataract which extended over the entire second half of life. The R diet did not result in different ascorbate levels in this lens. Aging was associated with a decrease in ascorbate in all the examined tissues except lens of both the R and C groups. It is not clear from these data that ascorbate is a prominent factor in the delay of cataract formation or other debilities in R Emory mice. However, it also appears unlikely that lens ascorbate is cataractogenic.

Aging↗
PubMed1995

The preparedness to share injecting equipment: an analysis using vignettes.

This paper reports on the use of vignettes to study drug injectors' preparedness to share injecting equipment. Separate vignettes referring to borrowing and passing on injecting equipment have been submitted to 505 injecting drug users in Glasgow. Injectors were asked to identify their own likely response in each of the situations described within the vignettes. It was shown that even among those injectors not reporting any actual sharing in the last 6 months a significant proportion would still be prepared to share injecting equipment within certain situations. The preparedness to share injecting equipment was seen to be influenced by such factors as social distance, sex and length of time injecting. It is suggested that even in situations where drug injectors may have modified their behaviour in the direction of lower levels of reported sharing, a propensity to share may remain. This suggests the continuing need to provide injectors with easy access to sterile injecting equipment; in addition, services working with injecting drug users may need to focus not only upon actual sharing behaviour but also upon what we have described here as the preparedness to share. Indeed, the latter dimension should stand as a warning to services of the potential for sharing injecting equipment to increase in the future.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Relations among aging, antioxidant status, and cataract.

Light and oxygen are necessary for the function of the eye. However, when present in excess or in uncontrolled circumstances, they appear to be related, probably causally, to the development of cataract. Compromises of function of the lens and retina with aging are exacerbated by depleted or diminished primary antioxidant reserves, antioxidant enzyme capabilities, and diminished secondary defenses such as proteases. Smoking appears to provide an additional oxidative challenge associated with depletion of antioxidants as well as with enhanced risk for cataract formation. Poor education and lower socioeconomic status are associated with poorer nutriture and are also significantly related to increased risk for these debilities. Optimizing nutriture, including diets rich in fruit and vegetables, may provide the least costly and most practicable means to delay cataract.

Aging↗
PubMed1995

An analysis of multinucleated blastomere formation in human embryos.

Human embryos were disaggregated into component blastomeres 42-72 h after insemination. The blastomeres were scored for the number of nuclei present and blastomeres of known nuclear morphology were returned to individual culture drops for 16-20 h, after which they were scored for cleavage and nuclear morphology. In all, 48% of mononucleated blastomeres cleaved during this period, but only 76% of these produced two mononucleated daughter blastomeres; in the remainder, one or more of the blastomeres was abnormally nucleated. During overnight culture, 30% of multinucleated blastomeres and 30% of anucleate blastomeres cleaved, the majority producing abnormally nucleated daughter blastomeres. The majority of blastomeres which showed no sign of cleavage after overnight culture retained the same nuclear morphology as when originally disaggregated. However, a small number of mononucleated blastomeres contained two nuclei after culture, indicating that karyokinesis may have taken place in the absence of cytokinesis. Overall, approximately 30% of blastomeres with more than one nucleus seemed to arise by this mechanism, the remainder probably arising by errors of chromosome segregation and/or packaging at mitosis. In addition, 25/111 mononucleated daughter cells arose either after abnormal division of mononucleated parent cells or after division of multinucleated cells, suggesting that approximately 23% of newly formed mononucleated cells might be chromosomally abnormal. The results of DNA quantitation indicated that very few (12/131, 9.2%) blastomeres (whether uni- or multinucleated) had a DNA content outside the 2-4C range. The embryos used for these studies had been cultured in one of three commonly used in-vitro fertilization (IVF) media: modified T6, Earle's balanced salts or Universal IVF medium (a commercial medium from Medi-Cult). A retrospective analysis was carried out of the number of embryos containing multinucleated blastomeres at disaggregation and of the total proportion of isolated blastomeres which were multinucleated in three groups of embryos, each of which had been cultured in one of the IVF media. Both these parameters were found to vary between cohorts of embryos cultured in the different media. The mechanism(s) by which culture medium composition might affect multinucleation of human blastomeres is discussed, as is the significance of these data for reliable preimplantation diagnosis of genetic status.

Blastomeres↗
PubMed1995

Thoracic outlet syndrome after motor vehicle accidents in a Canadian pain clinic population.

OBJECTIVE: To record symptoms and signs, operative findings, and long-term outcome in operated and nonoperated patients with the diagnosis of thoracic outlet syndrome after a motor vehicle accident. DESIGN: Descriptive prospective study. SETTING: Pain clinic population in the Toronto Hospital (Western Division), Toronto, Ontario, Canada. PATIENTS: Thirty-two patients diagnosed as having thoracic outlet syndrome after injuries sustained in a car accident (based on specific symptoms and signs as well as exclusion of other disorders generating brachialgia). INTERVENTIONS: Conservative management versus transaxillary or supraclavicular exploration of the thoracic outlet. OUTCOME MEASURES: Pain/symptom relief. RESULTS: Most patients presented with pain and paresthesiae, but conspicuous discoloration of the symptomatic extremity was seen in 41%. Osseous anomalies were seen in 22% of the patients in simple neck x-rays. Vascular studies were abnormal in 24% of tested patients. During transaxillary first rib resection in 15 patients, 87% were found to have musculotendinous and less often osseous anomalies compromising primarily the lower trunk of the brachial plexus. Long-term follow up demonstrated very good pain relief (based on patients' estimates) only in 47% of the operated patients and 20% of the conservatively treated patients. Reoperation was necessary in six cases through a supraclavicular decompression with only one patient experiencing substantial improvement with long-term follow-up. The difficulties in diagnosis as well as reasons for failures of conservative and surgical management are discussed, and the authors' current protocol for diagnosis and management is presented.

Accidents, Traffic↗
PubMed1995

Staff rotation: implications for occupational therapy.

Occupational therapy departments of tertiary care hospitals can provide staff with opportunities to gain diverse clinical experience if they rotate through the various services such as surgery, medicine, geriatrics, plastic surgery and orthopaedics. The system of rotation offers both advantages and disadvantages for the staff and the institution. The Royal Victoria Hospital in Montreal, a large university teaching hospital, had traditionally offered staff the opportunity to rotate. Changes in staffing and their needs however, resulted in rotation becoming an important issue within the department. This article presents the pros and the cons of rotation and non-rotation systems as identified by therapists and administrators across Canada. Staff rotation was found to have an effect on job satisfaction and a therapist's career orientation. Given these findings, administrators may want to reconsider the role of the generalist and specialist in their facilities.

Canada↗
PubMed1995

Educating preschoolers about sun safety.

OBJECTIVES: This feasibility study examined whether a sun safety curriculum designed for and administered to preschoolers affects their cognition (knowledge, comprehension, application) regarding sun safety. METHODS: Twelve classes of 4- to 5-year-olds were recruited from local preschools and randomly assigned to an intervention group or a control group. The intervention group received an investigator-developed sun safety curriculum; the control group did not. Children in both groups were tested at the beginning of the study about their cognition related to sun safety. They then received posttests 2 and 7 weeks following the pretest. RESULTS: The curriculum had a significant effect on the knowledge (P = .01) and comprehension (P = .006) components of cognition. The application component of cognition was not significantly changed by the curriculum. CONCLUSIONS: A structured curriculum was found to be an efficacious means of enhancing knowledge and comprehension of sun safety in preschool children. At the preoperational developmental stage, however, children may not be able to apply such knowledge and comprehension.

Analysis of Variance↗
PubMed1995

Clinical applications of renal scintigraphy.

Nuclear medicine techniques for evaluating the kidney and urinary tract have evolved from pioneering studies with primitive radiopharmaceuticals and hand-held probe detectors to a sophisticated technology capable of providing important physiologic and anatomic information. Advances in nuclear medicine and computer technology over the past decade have resulted in improved, clinically useful scintigraphic studies to assist clinicians in examining patients who have diseases of the genitourinary tract. However, renal scintigraphy is a complex subject. Five different radiopharmaceuticals are available for scanning the kidneys, multiple quantitative indexes can be generated, and protocols may vary depending on the clinical setting. The focus of this review is practical: to summarize the clinical advantages and disadvantages of the different radiopharmaceuticals; to review quantitative indexes that help interpret images; and to review the role of radionuclide scintigraphy in patients with suspected obstruction, pyelonephritis, and renovascular hypertension.

Humans↗
PubMed1995

A comparison of ubiquitin-dependent proteolysis of rod outer segment proteins in reticulocyte lysate and a retinal pigment epithelial cell line.

We compared ATP- and ubiquitin-dependent proteolysis in supernatants of rabbit reticulocyte lysate and a human retinal pigment epithelial (RPE) cell line. At pH 7.8, both preparations catalyzed the conjugation of [125I]ubiquitin to endogenous proteins, generating an equivalent amount of high mass (> 150 kDa) [125I]ubiquitin-protein adducts. Both preparations degraded exogenous histone 2A, oxRNase and beta-lactoglobulin in an ATP-dependent manner. Addition of ubiquitin (12 or 120 microM) to reticulocyte lysate stimulated (1.4-fold) ATP-dependent degradation only of histone 2A. Addition of 12 microM ubiquitin to RPE supernatant resulted in > or = 3-fold enhancement in degradation of all three substrates. Next, we compared the ability of the two proteolysis systems to degrade bovine rod outer segment (ROS) nonintegral membrane proteins. [125I]ROS protein degradation by reticulocyte lysate was almost exclusively ATP-dependent and was completely inhibited by hemin and vanadate, inhibitors of ATP- and ubiquitin-dependent proteolysis. RPE supernatant also degraded ROS proteins by an ATP-dependent mechanism, and, unlike results obtained in reticulocyte assays, this degradation increased (2-fold) upon ubiquitin supplementation. Both proteolysis systems degraded ROS proteins of molecular mass approximately 10, 30, 37, 40 and 60 kDa, with coincident formation of high mass species. Reticulocyte lysate also degraded 100 and 150 kDa ROS proteins, whereas RPE supernatant did not. The 10, 37 and 40 kDa species were identified by western blot as the gamma-, beta- and alpha- subunits of rod transducin (Gt), respectively. RPE supernatant generated (some) ROS proteolysis products that remained acid-precipitable. As compared with patterns of proteolysis in reticulocytes, RPE supernatant (1) degraded 100% more Gt beta gamma, (2) generated > 10-fold the amount of high mass (putative ubiquitin-ROS protein) conjugates and (3) preferentially degraded Gt beta gamma relative to G t alpha. The ubiquitin-dependent enhancement of ATP-dependent degradation of all proteins tested in RPE supernatant makes the RPE system a valuable experimental tool for the explicit demonstration of ubiquitin-dependent proteolysis.

Animals↗
PubMed1995

Measurement of carotenoids, retinoids, and tocopherols in human lenses.

PURPOSE: To determine the levels of carotenoids, retinoids, and tocopherols in normal and cataractous human lenses. METHODS: Concentrations of carotenoids, retinoids, and tocopherols were measured by high-performance liquid chromatography (HPLC) in 12 American normal lenses, 9 American cataractous lenses, and 10 Indian cataractous lenses. RESULTS: On a per gram wet weight of tissue basis, human lenses contained 11 to 25 ng xanthophylls (lutein and zeaxanthin), 31 to 50 ng retinol, 21 to 25 ng retinyl palmitate, 1573 to 2550 ng alpha-tocopherol, and 257 to 501 ng gamma-tocopherol. Concentrations of lutein, zeaxanthin, and retinol were significantly higher in Indian cataractous lenses than in American normal or cataractous lenses. There were no differences in the lutein-zeaxanthin, retinoid, or alpha-tocopherol contents between American normal lenses and American cataractous lenses. The range of ratios of lutein to zeaxanthin in human lenses was 1.6 to 2.2. The mean age of the Indian lens donors was 20 years younger than the American lens donors. Comparisons using contralateral lenses indicated that there was significant interindividual variance in human lens concentrations of xanthophylls, retinoids, and tocopherols. beta-carotene and lycopene, major carotenoids in human serum and other tissues, were not detected in human lenses. CONCLUSIONS: Xanthophylls (lutein and zeaxanthin) are the only carotenoids detected in human lens. Retinol, retinyl palmitate, and alpha- and gamma-tocopherols also are present in human lens. Determinants of lens concentration of nutrients are not defined, but dietary factors are likely to be important.

Carotenoids↗
PubMed1995

The use of a zinc based bioceramic as an osteoconductive agent in the rat model.

The many complications and risks of autograft and allograft bone have resulted in the search for an effective synthetic bone graft substitute [1,2]. The purpose of this study is to determine the effectiveness of ZCAP (zinc calcium phosphate) ceramic organic acid composite as an osteoconductive agent, including its possible benefits or risks for patients requiring bone grafting. A solid control model has been developed with an isolated mid-diaphyseal femur fracture immobilized by intramedullary threaded K-wire fixation. Two trials were performed in which two formulations of ZCAP composite ceramic were tested. The first, used in eighteen rats will be referred to as ZCAP1, the second, used in six rats will be referred to as ZCAP2. In the first trial rat femurs were augmented with 0.1 g ZCAP1 composite ceramic which varied in pore size. One pore size performed better than the others, so that pore size along with some minor changes in the composite design to increase resistance to the stresses inherent in our weight bearing model resulted in ZCAP2, which was tested in the second trial. The rats were sacrificed at ten weeks, during which time all rats remained viable. Blood work was done prior to sacrifice and radiography was done on all femurs. After sacrifice, gross morphological exam showed filling of the defect. Sections of the femurs from each group were analyzed by decalcified histological examination, electron microscopy, and tensile strength testing. The ZCAP composite ceramic had no significant effect on blood chemistry or body weight. Initial histological studies were consistent with endochondral ossification which was confirmed by electron microscopy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Measuring technetium-99m-MAG3 clearance with an improved camera-based method.

UNLABELLED: Because commercially available camera-based methods are not optimized, they fail to account for dose infiltration, table attenuation and correspondence between time of injection and starting the camera. We have developed a more optimized technique to calculate camera-based clearances and applied this technique in the design of a camera-based clearance method for 99mTc-MAG3. METHODS: Technetium-99m-MAG3 scintigraphy was performed in 20 patients who had varying degrees of renal function. Data were acquired posteriorly in supine patients at 2 sec/frame for 24 frames, 15 sec/frame for 16 frames and 30 sec/frame for 40 frames. Background correction was performed using an automated elliptical region of interest. Renal depth was estimated using improved regression equations and an empirically determined attenuation coefficient derived from phantom studies. Corrections were made for table attenuation and time discrepancies between dose injection and starting the camera. The percent injected dose in the kidney at 1-2, 1-2.5 and 2-3 min postinjection and the percent injected dose at those time periods corrected for body surface area were correlated with MAG3 clearance based on a single injection, two-compartment model. RESULTS: There was high correlation between the percent injected dose in the kidney at all three time periods and the multisample clearance. Correcting for body surface areas significantly improved the correlation coefficients. Consequently, regression equations were developed to predict multisample clearance based on percent dose and body surface area. CONCLUSION: The optimization features described in this method should improve precision when sequential studies are conducted in the same patient.

Adult↗
PubMed1995

School nursing. A collaborative approach to HIV/AIDS health promotion.

The involvement of school nurses in the planning, presentation and delivery of both general health education and sex education in schools in Wirral has been strengthened by the development since 1990 of the school nurses' HIV/Aids resource group. Ann Taylor and Joan Stott describe how they have worked closely with Wirral education authority personal and social education co-ordinators to devise a health promotion programme for school pupils and college students, and cascade training for school nurse colleagues, teachers and governers.

HIV Infections↗
PubMed1995

Biotyping of Escherichia coli in microwell plates.

A simple, inexpensive scheme of eight tests for biotyping strains of Escherichia coli in microwell plates is described. The tests comprise primary tests for the fermentation of raffinose, sorbose, ornithine, dulcitol and 2-deoxy-D-ribose, and secondary tests for rhamnose fermentation, lysine decarboxylation and motility. Among a collection of 75 clinical isolates of Esch. coli from 12 patients, 18 full biotypes designated according to their positive and negative reactions in the eight tests were distinguished. These biotypes gave an indication of the natural history of patients' infections. Because it provides excellent and reliable type discrimination, biotyping can be used in a combination with other typing techniques to resolve local epidemiological problems involving Esch. coli.

Adolescent↗
PubMed1995

Differential consequences of left- and right-sided chronic pain.

OBJECTIVE: To test the neuropsychological hypothesis that left-sided pain will have more adverse consequences than right-sided pain by virtue of activation of the "depressogenic" right hemisphere. DESIGN: A retrospective analysis comparing data of chronic pain patients with left-sided pain to patients with right-sided pain. PATIENTS: All of the right-handed patients (n = 85) presenting with unilateral shoulder, arm, and hand pain and suspected of having Thoracic Outlet syndrome (TOS) were assessed as potential candidates for surgery at the Toronto Western Hospital Pain Investigation Unit over a 5-year period. OUTCOME MEASURES: Minnesota Multiphasic Personality Inventory (MMPI), SIP (Sickness Impact Profile). RESULTS: Contrary to the intuitive expectation that right-sided pain would be more disruptive in right-handed subjects, patients with left-sided pain had higher MMPI scores for hysteria and hypochondriasis and also had higher scores on the physical dimension of the SIP. CONCLUSION: Differences between the groups could not be accounted for by different etiologies because the proportions and causes of left- and right-sided pain were comparable. The results are consistent with the hypothesis that unilateral stimulation activates the contralateral cerebral hemisphere and arouses the emotions associated with that hemisphere.

Adult↗
PubMed1995

Inhibition of intimal hyperplasia and occlusion in Dacron graft with heparin and low molecular weight heparin.

OBJECTIVE: Intimal hyperplasia (IH) is a significant cause of late prosthetic graft occlusion. The influence of heparin and low molecular weight heparin (LMWH) on IH was studied in a sheep model. EXPERIMENTAL DESIGN: A gelatin sealed Dacron (Gelsoft) interposition vascular graft was placed end to end in sheep carotid artery. Standard heparin (SH) was administered in a dose of 7,500 units twice daily subcutaneously (n = 6). LMWH (enoxaparin) was administered in two dosages, a "low dose" of 2 mg/kg (n = 6) and a "high dose" of 5 mg/kg (n = 6) subcutaneously daily. A control group received a graft but no heparin (n = 6). At one month the animals were sacrificed and the grafts sectioned. An intimal measurement was obtained under light microscopy using an eyepiece graticule from a longitudinally sectioned graft. RESULTS: Controls occluded five grafts of six and recorded a mean intimal thickness of 2,510 micrometres, SH sheep occluded two with a mean thickness of 83 (p < 0.05), low dose enoxaparin sheep had no occlusions with a mean thickness of 73 (p < 0.001) and high dose enoxaparin sheep occluded one with a mean thickness of 225 (p < 0.01). The reduced occlusion rates were significant for the LMWH groups (p = 0.007 for low dose, p = 0.04 for high dose) but not for SH. There were no significant differences between treatment groups with respect to IH. CONCLUSIONS: In this sheep animal study, each of SH and two LMWH dose regimens resulted in a reduction in Dacron vascular graft occlusion rate and the development of IH, with the greatest effect seen in the low dose LMWH group.

Animals↗
PubMed1994

Evaluation of intravenous lidocaine for the termination of sustained monomorphic ventricular tachycardia in patients with coronary artery disease with or without healed myocardial infarction.

Prospective evaluations of intravenous lidocaine as therapy for sustained monomorphic ventricular tachycardia (VT) in the absence of acute myocardial infarction are lacking. Lidocaine has been promulgated as first-line therapy in patients with VT, but studies evaluating its efficacy in the electrophysiology laboratory suggest that it has poor effects in terminating or preventing induction of VT. Thus, this study sought to evaluate the clinical effectiveness of lidocaine in 3 cohorts with induced or spontaneous VT. One hundred twenty-eight patients with stable VT, occurring either spontaneously or induced at the time of electrophysiologic study either in the baseline state or at the time of pharmacologic testing, were evaluated. The response rate to lidocaine therapy as manifested by termination of VT was the primary goal of the study. Of these patients, 10 (8%) had termination of VT after lidocaine therapy. There were no significant differences in age, ejection fraction, VT cycle length, and mean dose of lidocaine between responders and 118 nonresponders. There were no serious side effects or adverse events (death, myocardial infarction, angina, or congestive heart failure). Lidocaine, although safe, is ineffective in terminating stable VT not associated with acute myocardial infarction.

Adult↗