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Biomedical subjects

A Harris

Publications and source records attributed to A Harris.

At least 559 records · Page 31Linked to original sources
PubMedDate not supplied

Age-related macular degeneration: a review of experimental treatments.

Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in the USA. Laser photocoagulation of choroidal neovascular membranes (CNVMs) in exudative AMD is currently the only well-studied and widely accepted treatment modality. It is beneficial for only a small minority of patients who show well-demarcated "classic" CNVMs, and it destroys normal retinal tissue, creates a scotoma, and is associated with an unacceptably high CNVM persistence and recurrence rate. Consequently, investigators have attempted to develop new modalities for treatment of CNVMs. These treatment modalities can be grouped into four major categories: photodynamic therapy; pharmacologic inhibition of CNVM formation with antiangiogenic agents; surgical intervention, including excision of subfoveal CNVMs; and radiation therapy. All of these experimental treatment modalities are directed toward destroyiing CNVMs, the end result of the exudative process, and all have limitations. The ideal treatment of the future must be based on the pathogenesis of the disease at a stage well before CNVMs develop. Investigations in nonexudative AMD are currently focusing on several major areas. Epidemiologic factors, such as genetics, sunlight, and nutrition, are being evaluated in several large studies, including the Age-Related Eye Disease Study, with the possibility of ultimately limiting the risk of AMD through behavior modification. Laser treatment of drusen is being evaluated as a means of limiting the risk of CNVM formation, although mixed results have been reported in the small number of studies to date. Choroidal perfusion abnormalities have been described in AMD, and some investigators postulate that altering blood flow may limit the risk of CNVM formation. No perfusion-treatment trials have been completed to date.

Choroidal Neovascularization↗
PubMedDate not supplied

Production of cytotoxic canthin-6-one alkaloids by Ailanthus altissima plant cell cultures.

Ailanthus altissima (Mill.) Swingle was established as callus- and cell-suspension cultures. Canthin-6-one and 1-methoxycanthin-6-one were isolated by a combination of preparative tlc and preparative hplc. The two alkaloids were identified by their uv, ms, and 1H-nmr spectra. The combined yield of the two alkaloids was 1.38% of dry weight from callus and 1.27% of dry weight from cell suspensions. The cytotoxicities of canthin-6-one, 1-methoxycanthin-6-one, 5-methoxycanthin-6-one, and canthin-6-one-3-N-oxide to guinea pig ear keratinocytes have been compared, and the IC50 values range from 1.11 to 5.76 micrograms/ml. There is no significant difference in activity among these four cytotoxic alkaloids.

Alkaloids↗
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[Digital fluorescein angiography in follow-up of the clinical course in therapy of patients with central vein occlusion and cystoid macular edema].

BACKGROUND: Fluorescein angiography with a scanning laser ophthalmoscope allows the quantification of morphologic and dynamic changes in the retina. In two patients with central retinal vein occlusion we monitored the progression of the cystoid macular edema (CME) and changes of microcirculation with a follow up of 4 to 6 months. MATERIALS AND METHODS: Two patients with central retinal vein occlusion and CME were examined by means of digital fluorescein angiography. Arteriovenous passage times and macular capillary blood velocities in combination with quantifications of the macular angioarchitecture and the extent of the CME were evaluated. RESULTS: Hemodilution therapy improved retinal circulation, whereas macular circulation and the severity of the CME remained unchanged. With persisting CME oral acetazolamid therapy was initiated. Oral Acetazolamide led to resorption of the cystoid edema in tandem with improved macular circulation. The capillary density was altered but remained unchanged over time. CONCLUSIONS: By means of digital analysis of fluorescein angiograms a detailed monitoring and retinal and macular dynamics, macular morphology is possible. In these two cases CME improved after Acetazolamide and moreover retinal circulation returned to normal conditions.

Acetazolamide↗
PubMedDate not supplied

Nosocomial infections due to Pseudomonas aeruginosa: review of recent trends.

The role of Pseudomonas aeruginosa in nosocomial infections occurring since 1975 is reviewed. Data from the National Nosocomial Infections Study conducted by the Centers for Disease Control, from individual medical centers, and from the literature were used to compare the relative frequency of occurrence of nosocomial infection caused by P. aeruginosa with that of infection caused by other gram-negative bacilli. The relative frequency of P. aeruginosa as a nosocomial pathogen has increased, although wide variations are seen among individual medical centers. P. aeruginosa continues to be a major pathogen among patients with immunosuppression, cystic fibrosis, malignancy, and trauma. While Staphylococcus aureus has become the predominant pathogen in some large burn centers, P. aeruginosa is the most important gram-negative pathogen. Periodic review of the epidemiology of P. aeruginosa infection is warranted in view of the changing incidence of infection caused by this organism.

Agranulocytosis↗
PubMedDate not supplied

Desensitization of oxytocin receptors in human myometrium.

In the present study, we investigated the possible mechanisms by which oxytocin might regulate oxytocin receptor (OTR) density. Exposure of cultured myometrial cells to oxytocin for a prolonged period caused desensitization: the steady-state level of oxytocin binding was 210 x 10(3) binding sites/cell, but this was time-dependently reduced to 20.1 x 10(3) sites/cell by exposing the cells to oxytocin for up to 20 h. In contrast, Western blotting data showed that the total amount of OTR protein was not affected by oxytocin treatment for up to 24 h. Flow cytometry experiments demonstrated that OTRs were not internalized during this treatment. However, RNase protection assays and Northern analysis showed that in cultured myometrial cells OTR mRNA was reduced by oxytocin treatment to reach a new low steady-state concentration. Analysis of this mRNA in myometrial biopsies from 17 patients undergoing emergency Caesarean section showed how it decreased with advancing labour. Samples obtained after 12 h of labour contained approximately 50 times less OTR mRNA than samples obtained from patients in labour for less than 12 h. We speculate that this decrease in OTR mRNA represents in-vivo OTR desensitization.

Cells, Cultured↗
PubMedDate not supplied

Concentrations of butriptyline in biological fluids following a fatal overdose.

A fatality resulting from the ingestion of butriptyline is reported. The compound was identified by mass spectral, gas chromatographic, and Fourier transform-infrared spectroscopic analysis. Identification was confirmed with a commercially available standard. Quantitation and identification details are presented.

Adolescent↗
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Enrollment management.

Attracting and retaining students in schools of nursing are of crucial importance to faculty. Although enrollment management functions are not part of the traditional faculty role, the authors describe how nursing faculty in a private liberal arts college instituted and implemented a successful enrollment management plan.

Advertising↗
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Reproducibility of nerve fiber layer thickness measurements using optical coherence tomography in silicone oil-filled eyes.

PURPOSE: To evaluate the reproducibility of nerve fiber layer (NFL) thickness measurements by optical coherence tomography (OCT) in individuals with silicone oil-filled eyes. METHODS: Eighteen patients who had undergone pars plana vitrectomy and silicone oil tamponade for retinal detachment were enrolled in a prospective, case-controlled clinical study. Each patient underwent OCT measurement of NFL thickness. Five repetitions of a series of scans on five separate occasions within a 0.5-month period were performed. Each eye was scanned at two different nerve head programs [radius (R) = 1.5 and R = 1.73]. The contralateral healthy eye was used as control. For each option (R = 1.5 and R = 1.73) and region (superior, inferior, temporal, nasal and overall mean), variance components and intraclass correlation coefficients (ICCs) were determined using repeated-measures regression. In these models, NFL thickness, as measured by OCT, was considered to have three variance components: intersubject, intervisit (within subject, between dates), and intravisit (within subject, within date). The ICC (intersubject variance/total variance) was used as a measure of reliability. RESULTS: The contralateral healthy eye provided a higher degree of reproducibility than the silicone oil-filled eye (p = 0.0001). Reproducibility was higher in a given eye on a given visit than from visit to visit. Reproducibility as measured by ICCs was as follows: R = 1.5, 0.54/0.30 (control eyes/silicone oil-filled eyes); R = 1.73, 0.51/0.30. CONCLUSIONS: Reproducibility results for OCT measurement of NFL thickness are different in healthy eyes and silicone oil-filled eyes. NFL thickness measurement is not reliable in silicone oil-filled eyes.

Case-Control Studies↗
PubMedDate not supplied

A CA repeat in the first intron of the CFTR gene.

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, that encompasses 250 kb of genomic DNA, cause cystic fibrosis. More than 5-10% of CF patients in most populations studied carry undefined mutations and hence intragenic CA repeats are important tools in genetic counselling. To date, polymorphic intragenic repeats have been found in introns 6a, 8 and 17b. We have identified a novel CA repeat within intron 1 of the CFTR gene that lies about 70 kb 5' to intron 6a and so will be a useful additional diagnostic marker.

Alleles↗
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Effect of intravenous droperidol on intraocular pressure and retrobulbar hemodynamics.

PURPOSE: Topically-applied dopamine antagonists reduce intraocular pressure (IOP) and inrease retinal blood flow in animal models. We examined the acute effects of intravenous infusion of a dopamine blocker (droperidol) on these parameters in healthy humans. METHODS: Sixteen subjects free from ocular or systemic disease (mean age 33 +/- 10 yrs) received either 5 mg i.v. droperidol over 5 minutes, or i.v. saline placebo in double-masked fashion. IOP was determined 30 and 60 minutes later, while color Doppler imaging was used to determine flow velocities in the ophthalmic, central retinal, and nasal and temporal posterior ciliary arteries 60 minutes after drug infusion. RESULTS: 30 minutes after drug infusion, IOP was reduced 6.0 mmHg as compared with baseline (p<0.001); after 60 minutes, IOP remained reduced by 3.7 mmHg (p<0.001). Placebo had no effect on IOP. While droperidol slightly elevated blood pressure and increased the calculated ocular perfusion pressure, the drug reduced visual acuity and contrast sensitivity (p<0.05). Droperidol elevated peak systolic velocity in the central retinal and nasal posterior ciliary arteries, without changing end-diastolic velocity or the resistance index in either of these vessels. Droperidol had no effect on flow velocities in the ophthalmic artery or the temporal posterior ciliary artery. CONCLUSIONS: The rapid and marked ocular hypotension resulting from intravenous droperidol suggests that this agent may prove useful in the management of acute ocular hypertension. The retrobulbar changes consequent to the ocular tension reduction likely represent autoregulatory responses to altered ocular perfusion pressure.

Adult↗
PubMedDate not supplied

Pulsatile ocular blood flow during pregnancy.

PURPOSE: To study pulsatile ocular blood flow (POBF) throughout pregnancy. METHODS: We enrolled twenty-seven healthy women in the first trimester of gestation, only ten of which were followed through the second trimester, and fourteen non pregnant healthy women. In each subject we measured POBF with the POBF pneumotonometer (OBF Ltd. UK), IOP, blood pressure (BP) and heart rate (HR). An unpaired Student t-test was used to compare pregnant women with non-pregnant women, and a two-tailed paired Student t-test was used to compare the same women in the first and second trimester of pregnancy. p <0.05 is considered statistically significant. RESULTS: Results are presented as means +/- SD. In the first trimester of pregnancy the age was 32 +/- 6, POBF 1516.4 +/- 382 ml/min, IOP 13 +/- 3 mmHg, BP 92 +/- 6 mmHg, and HR 86 +/- 14 beats/min. In the second trimester POBF was 1629.11 +/- 352.4 ml/min, intraocular pressure (IOP) 12 +/- 3 mmHg, BP 96 +/- 3 mmHg, and HR 93 +/- 10 beats/min. In the control group the age was 27 +/- 9, POBF 972.23 +/- 329.3 ml/min, BP 88 +/- 4.3 mmHg, and HR 80 +/- 14 beats/min. POBF increases during the first trimester (p = 0.00008). In the second trimester POBF was higher compared to the first trimester (p = 0.0008). Non significant differences were observed for the other parameters. CONCLUSIONS: The POBF increases throughout gestation. During pregnancy there is an increase in estrogen which induces endothelial-dependent vasodilatation in several tissues. The estrogen changes may influence POBF.

Adolescent↗
PubMedDate not supplied

Comparative analysis of the effects of dorzolamide and latanoprost on ocular hemodynamics in normal tension glaucoma patients.

PURPOSE: To compare the effects of latanoprost (Xalatan) and dorzolamide (Trusopt) on ocular hemodynamics in normal-tension glaucoma patients. METHODS: A randomized, single-masked, parallel design study was conducted. After a 4-week washout period, 20 normal tension glaucoma patients, recruited from a single university-based ophthalmology clinic, received either latanoprost once daily or dorzolamide 3 times daily for 4 weeks. The subjects were examined at baseline and post-treatment. Outcome measures included heart rate (HR), blood pressure (BP), logMar visual acuity (VA), contrast sensitivity (CS), intraocular pressure (IOP), color Doppler imaging (CDI), and fluorescein angiography with the Rodenstock scanning laser ophthalmoscope (SLO). CDI measurements of the retrobulbar vessels included peak systolic velocity, end diastolic velocity, and the calculated resistance index. Arterio-venous passage time (AVP) in the superior and inferior temporal retina was calculated from the SLO angiograms. RESULTS: Neither dorzolamide nor latanoprost had any statistically significantly effect on HR or BP. Both drugs significantly lowered IOP without altering calculated ocular perfusion pressure (p<0.05). There was no statistically significant difference in any CDI measurement. Dorzolamide significantly decreased AVP time in the superior retina (p=0.011), while latanoprost did not (p=0.62). CONCLUSIONS: Dorzolamide, unlike latanoprost, significantly reduced AVP times in the superior temporal retina in normal tension glaucoma (NTG) patients.

Adult↗
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Professional issues facing nurse practitioners and nursing.

Legislative changes relating to professional nursing practice and a reduction in junior doctors' working hours have led to an increase in the number of nurse practitioners in the UK. While the educational preparation for these new roles is varied, the challenges faced by nurse practitioners are similar in nature and have implications for the nursing profession as a whole. The measures that can facilitate the development of individual nurse practitioners include: effective communication and negotiation regarding the introduction of their role; clearly defined and documented role descriptions; clarification regarding areas of risk and liability; and organizational and professional support. The stance of the nursing profession in relation to the development of the nurse practitioner role is also explored and questions are raised about cross-boundary working, future role development, and the impact of nurse practitioners on the delivery of patient care.

Communication↗
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Impact of urinary incontinence on the quality of life of women.

There is a lot of debate among continence specialists as to the impact that urinary incontinence (UI) has upon the sufferer's quality of life (QoL). Furthermore, healthcare professionals involved in delivering care are examining ways to measure the outcomes of their healthcare interventions, in terms of not only symptom relief, but also patient-specified improvements to QoL. Healthcare professionals have yet to agree upon one standard tool for measuring the effect of UI upon sufferers' QoL. This article examines some of the current research on UI as experienced by females living in their own homes and its impact on their QoL.

Female↗
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Preparing nurses for the acute care case manager role: educational needs identified by existing case managers.

BACKGROUND: There is little in the literature about how best to prepare nurses for case manager roles. METHOD: Twenty acute care case managers were asked to identify skills and knowledge that would be of value to nurses new to case manager roles. RESULTS: Community resources, discharge planning, and third party reimbursement were the top three educational needs identified by all case managers. Baccalaureate prepared case managers identified clinical issues to be of value, such as family coping, patient education, quality of life, and social support, while master's prepared nurses identified only system-related issues. CONCLUSION: Educational programs preparing baccalaureate prepared case managers could focus on both clinical and system issues, while programs preparing master's educated case managers could focus primarily on managing system issues. Staff development professionals may also call on experts inside and outside the institution to assist in teaching about health care finance and reimbursement issues.

Acute Disease↗