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Biomedical subjects

M A Terry

Publications and source records attributed to M A Terry.

At least 19 recordsLinked to original sources
PubMed2001

Endothelial replacement without surface corneal incisions or sutures: topography of the deep lamellar endothelial keratoplasty procedure.

PURPOSE: To evaluate the immediate postoperative corneal topography after the deep lamellar endothelial keratoplasty procedure. METHODS: Eight eye bank eyes underwent deep lamellar endothelial keratoplasty through a 9.0-mm limbal incision replacing the central 7.0 mm of posterior stroma and endothelium through the lamellar pocket wound. Orbscan topography was performed before and after surgery, and simulated keratometry readings and central corneal diopter power were recorded. The change in astigmatism and corneal power from preoperative to postoperative readings was then determined. RESULTS: The net change in corneal astigmatism averaged 0.4+/-0.5 diopters (range, -0.1 to 1.1 diopters). The net change in corneal power averaged -0.2+/-0.4 diopters of flattening (range, -0.9 to +0.2 diopters). Neither the astigmatism nor the corneal power levels after this surgery were significantly different from the preoperative topography (p = 0.22 and 0.27, respectively). CONCLUSIONS: The deep lamellar endothelial keratoplasty procedure, with its absence of corneal surface incisions or sutures, has no significant effect on immediate postoperative corneal topography. The potential advantages of this procedure over penetrating keratoplasty in the treatment of endothelial dysfunction are considerable.

Astigmatism↗
PubMed2001

Deep lamellar endothelial keratoplasty in the first United States patients: early clinical results.

PURPOSE: To report the early clinical results of the first U.S. patients to undergo deep lamellar endothelial keratoplasty (DLEK) surgery for the treatment of endothelial dysfunction. METHODS: Two patients with pseudophakia with Fuchs' endothelial dystrophy, under an Institutional Review Board-approved protocol, underwent replacement of the endothelium through a limbal, scleral pocket incision (DLEK). Their vision, pachymetry, and corneal map topography were measured in the early postoperative period and were compared with preoperative measurements. RESULTS: Both patients had improvement in all parameters within 1 month after surgery, and corneal topography showed no significant change from before the surgery. The first patient's vision at 6 months was 20/40 (+2) with a 0.75-diopter (D) decrease in astigmatism and a normal pachymetry of 573 microm. The second patient's vision at 6 months was 20/40 (-2) with a 0.25-D increase in astigmatism and a pachymetry of 618 microm. Graft endothelial cell counts at 6 months were 1,692 and 2,631 cells/mm2, respectively. CONCLUSION: The DLEK procedure, with its absence of corneal surface incisions and sutures, preserves the preoperative topography and demonstrates good donor endothelial cell count and function early in the postoperative period. If interface clarity can be maintained, the potential advantages over penetrating keratoplasty in the treatment of endothelial dysfunction are considerable.

Aged↗
PubMed2001

Dry eye in the elderly.

Dry eye in the elderly population is a condition with a multitude of contributing factors and a wide spectrum of severity. The complex tear film is made up of layers of oil, aqueous and mucin, produced by the meibomian glands, main and accessory lacrimal glands, and by the goblet cells, respectively. Alteration in the normal function of any of these structures by disease, trauma or the environment can cause dysfunction of the tear film and result in the symptoms of dry eye (such as burning, grittiness and blurred vision). Normal lid anatomy and closure is critical to prevent evaporation of the normal tear film. The mainstay of current therapy is augmentation of the tear film with artificial tears and ointment. More severe cases of dry eye may require occlusion of the tear drainage system with plugs or electrocautery scarring. Good lid hygiene is also important for tear film health. A new paradigm of dry eye as a subclinical inflammatory disease has recently been suggested, and preliminary results from treatment with topical cyclosporin formulations are encouraging. The next few years promise exciting advances and relief for patients suffering from this chronic condition.

Aged↗
PubMed2001

A comprehensive investigation of barriers to adult immunization: a methods paper.

OBJECTIVE: Immunization rates for influenza and pneumococcal vaccines among the elderly (especially minority elderly) are below desired levels. We sought to answer 4 questions: (1) What factors explain most missed immunizations? (2) How are patient beliefs and practices regarding adult immunization affected by racial or cultural factors? (3) How are immunizations and patient beliefs affected by physician, organizational, and operational factors? and (4) Based on the relationships identified, can typologies be created that foster the tailoring of interventions to improve immunization rates? STUDY DESIGN: A multidisciplinary team chose the PRECEDE-PROCEED framework, the Awareness-to-Adherence model of clinician response to guidelines, and the Triandis model of consumer decision making as the best models to assess barriers to and facilitators of immunization. Our data collection methods included focus groups, face-to-face and telephone interviews, self-administered surveys, site visits, participant observation, and medical record review. POPULATION: To encounter a broad spectrum of patients, facilities, systems, and interventions, we sampled from 4 strata: inner-city neighborhood health centers, clinics in Veterans Administration facilities, rural practices in a network, and urban/suburban practices in a network. In stage 1, a stratified random cluster sample of 60 primary care clinicians was selected, 15 in each of the strata. In stage 2, a random sample of 15 patients was selected from each clinician's list of patients, aiming for 900 total interviews. CONCLUSIONS: This multicomponent approach is well suited to identifying barriers to and facilitators of adult immunizations among a variety of populations, including the disadvantaged.

Aged↗
PubMed2000

The evolution of lamellar grafting techniques over twenty-five years.

The history of lamellar keratoplasty (LK) surgery spans over 100 years, and the advantages of lamellar surgery have long been known. The surgery is usually used for tectonic purposes; however, new techniques and technology over the past 25 years have expanded the applications of LK in optical rehabilitation. Instrumentation such as viscoelastics, diamond knives, ultrasonic pachymetry, artificial anterior chambers, advanced microkeratomes, and the excimer laser have enhanced our ability to work more safely in the tedious microsurgical environment of the lamellar procedure. Advances in surgical techniques such as deep lamellar anterior keratoplasty and deep lamellar endothelial keratoplasty have expanded the application of lamellar surgery to endothelial replacement and have achieved visual results approaching those of penetrating keratoplasty while reducing the rate of rejection and improving the long-term graft stability. As research continues, LK promises to be an increasingly important option for the corneal surgeon.

Corneal Diseases↗
PubMed2000

From science to application: the development of an intervention package.

Many community-based organizations and health departments want to implement HIV prevention interventions with scientifically demonstrated effectiveness. The Replicating Effective Programs (REP) project supported researchers in developing intervention packages designed to help prevention partners replicate effective programs in their settings. Intervention packages convey the intervention's foundation, components, and methods and are one part of a larger system needed to transfer research-based HIV prevention technology to service providers. Implementation packages were developed using a multistage process. The original researchers drafted the materials, advisory groups reviewed the packages, and adopting agencies used the materials in trial runs. The advisory groups and adopting agencies recommended extensive use of examples, thorough explanations about the rationale for each intervention component, explicit representation of people of color in the materials, clear statements about the intended audience(s), and an easy-to-use and visually appealing format. Packages were revised based on these recommendations and the outcomes of the trial runs.

Community Health Services↗
PubMed2000

Orientation and training: preparing agency administrators and staff to replicate an HIV prevention intervention.

Effective orientation and training are fundamental to the successful implementation of any intervention because they communicate the critical first impressions of the intervention and the skills needed to conduct it. When research-based HIV prevention interventions are translated into practice, issues arise that require adaptation and expansion of the basic functions of orientation and training. This article identifies some of these issues by drawing on the experience of researchers in the Replicating Effective Programs (REP) project. The purpose, structure, and instructional approach of the orientation and training for administrators, staff, and volunteers are described in depth for one project, with comparisons and additional examples from others. Based on these descriptions, critical issues for orientation and training for replication are presented. These include extending orientation and training to a broad audience within the adopting agency, allocating sufficient time to ensure understanding of the intervention, and planning for staff turnover.

Community Health Services↗
PubMed2000

Transfer of research-based HIV prevention interventions to community service providers: fidelity and adaptation.

HIV prevention research interventions usually follow protocols with specific procedures. If a community-delivered intervention uses the same procedures with the same populations as those in the original research, the behavior change effects should be similar. However, community-based providers may not replicate an intervention exactly as it was conducted in the effectiveness study. Adaptation may be needed to better meet the needs of the clients, community, or organization. We propose that interventions can be defined in terms of core elements likely to be responsible for effectiveness. These core elements cannot be changed without fundamentally changing the intervention, whereas other characteristics may be modified without altering effectiveness. HIV prevention researchers and service providers can collaborate to develop interventions that not only are effective but can also be successfully implemented by service organizations. If researchers actively involve service providers and community members in intervention planning, technology transfer goals can be better achieved.

Community Health Services↗
PubMed2000

The role of technical assistance in the replication of effective HIV interventions.

This article examines the role of technical assistance (TA) in supporting the replication of proven HIV interventions. A case study of the replication of the VOICES/VOCES intervention elucidates the level and types of TA provided to support new users through the adoption process. TA included help in garnering administrative support, identifying target audiences, recruiting groups for sessions, maintaining fidelity to the intervention's core elements, tailoring the intervention to meet clients' needs, strengthening staff members' facilitation skills, troubleshooting challenges, and devising strategies to sustain the intervention. Two to four hours per month of TA were provided to each agency adopting the intervention, at an estimated monthly cost of $206 to $412. Findings illustrate how TA supports replication by establishing a conversation between the researcher TA providers experienced with the intervention and new users. This communication helps preserve key program elements and contributes to ongoing refinement of the intervention.

Community Health Services↗
PubMed1999

Oxidative cell membrane alteration. Evidence for surfactant-mediated sealing.

Exposure to very intense ionizing irradiation produces acute tissue sequelae including inflammation, pain, and swelling that often results in tissue fibrosis and/or necrosis. Acute tissue necrosis occurs in hours when sufficiently rapid damage to membrane lipids and proteins leads to altered membrane structure, disrupting the vital electrochemical diffusion barrier necessary for cell survival. This damage mechanism is thought to underlie the interphase death of lethally irradiated postmitotic cells such as neurons, but it has also been implicated in the rapid cell death of lymphocytes and acute vascular changes due to capillary epithelium dysfunction. It is not known whether sealing of radiation-permeabilized cell membranes will prolong survival of lethally irradiated cells or perhaps lead to repair of damaged nucleic acids. The purpose of this study is to begin to address the first question.

Cell Membrane↗
PubMed1999

Evaluation of prior photorefractive keratectomy in donor tissue.

PURPOSE: To describe a case in which an eye donor had prior bilateral photorefractive keratectomies and to elucidate possible methods of evaluation and screening of donor tissue. METHODS: Case report. A 62-year-old eye donor was reported to have received radial keratotomy before his death. Further investigation by the eye bank showed a history of photorefractive keratectomy (PRK), not radial keratotomy. The corneas were therefore not used for transplantation, and the eyes were evaluated by slit-lamp examination, photography, corneal topography, and histology. RESULTS: Slit-lamp and photographic examination did not indicate the presence of PRK ablations. Corneal topography mapping with the TMS-1 was relatively ambiguous for identifying PRK flattening, while multiple data formatting of the cornea with the Orbscan resulted in the strongest suggestion of prior PRK. Histologic analysis showed central corneal thinning and loss of Bowman's membrane consistent with PRK. CONCLUSIONS: In the absence of a positive donor history for PRK, current methods of screening donor tissue for prior PRK often are insufficient to exclude these corneas from use in transplantation. More refined placido imagery corneal topography or newer technologies such as the Orbscan may allow more sensitive and specific methods of donor tissue screening.

Contraindications↗
PubMed1999

New screening methods for donor eye-bank eyes.

PURPOSE: Current methods of screening donor eyes for corneal transplantation are not always effective in excluding corneas with abnormal topography. We used the Orbscan to determine whether corneal-thickness maps could be used as a technique for donor tissue screening. METHODS: Forty eye-bank eyes were measured with the Orbscan, and a corneal-thickness map was generated. Average central pachymetry measurements from each map were compared with the thinnest midperipheral thickness reading. Two eyes from a donor who had photorefractive keratectomy (PRK) and two eyes from a donor with keratoconus were then compared with the normal donor eye results. RESULTS: The average difference between the thinnest midperipheral pachymetry and the central pachymetry in the control group was 0.040 +/- 0.026 mm. The eyes from the donor with PRK showed larger disparities between the central and midperipheral thicknesses because of the thinned central cornea, with differences of 0.154 mm in the right eye and 0.106 mm in the left eye. The eyes from the donor with keratoconus had midperipheral corneas that were thinner than the center, indicating eccentric, ectatic cones. The differences in thickness between the center and midperiphery in the eyes from the donor with PRK and the donor with keratoconus differed from the control group by >2 SD. CONCLUSIONS: Diseases or surgery that affect the relationship between the central and midperipheral corneal thickness may be screened through Orbscan pachymetry mapping with comparison with a normal range.

Aged↗
PubMed1999

The Women and Infants Demonstration Project: an integrated approach to AIDS prevention and research.

The Women and Infants Demonstration Project is a multisite, behavioral intervention research effort funded by the Centers for Disease Control. The project is evaluating a theory-based, integrated intervention model to increase the use of condoms for prevention of both sexually transmitted diseases (STDs) and unintended pregnancy among women and their partners at risk of infection with HIV. The importance of utilizing carefully targeted, credible and persistent risk reduction interventions to effect lasting behavior change has become evident over the last ten years of the AIDS epidemic. The theory-based intervention components being evaluated in this intervention study involve one-on-one stage-tailored outreach; the development and distribution of community-tailored HIV prevention materials, called role-model stories; and the development of organizational and peer networking, all within a community mobilization framework. This article describes each of the intervention components being evaluated during this 5-year study. Such an intervention effort represents an important contribution in the design of community-level AIDS prevention intervention efforts which support individual-level behavioral changes by women at risk for HIV and other sexually transmitted infections.

Adolescent↗
PubMed1996

Hydration effects on corneal topography.

OBJECTIVE: To evaluate the effect of corneal thickness changes on the central and paracentral corneal topography in de-epithelialized eye-bank eyes at various stages of hydration. METHODS: Corneal topography of 12 eye-bank eyes was measured with a videokeratoscope at the following four stages of hydration: prethinning (mean pachymetry, 0.88 mm), postthinning (0.55 mm), after 15 minutes of rehydration (0.60 mm), and after 30 minutes of rehydration (0.64 mm). RESULTS: Corneal thickness changes were significant between each stage of hydration (P < .05 by repeated-measures analysis of variance). No net astigmatic shifts were observed between any stage of hydration (P = .45). From prethinning to postthinning, dehydration produced average central corneal steepening of 0.44 diopters (P < .001), and average paracentral steepening of 0.89 D (P < .001). Significant changes in corneal power were not measured during normal rehydration until 30 minutes posthydration, when the central cornea had flattened an average of 0.3 D from normal thickness (postthinning) levels (P < .05). CONCLUSIONS: Substantive thinning of corneal tissue caused statistically significant but clinically minimal ( < 1 D) central and paracentral steepening, but smaller corneal hydration changes that can occur during experimental and surgical procedures had little effect on corneal topography.

Aged↗
PubMed1994

Hydration changes in cadaver eyes prepared for practice and experimental surgery.

OBJECTIVES: To identify reliable and efficient methods of thinning postmortem corneas for surgical experiments and to develop methods of maintaining stable corneal thickness. METHODS: Three methods of corneal thinning were evaluated by group: group A, increased intraocular pressure; group B, exchange of anterior chamber fluid with dextran solution and immersion in dextran solution; and group C, immersion in dextran solution without aqueous replacement. The stability of the thinned central cornea was then evaluated by exposing 30 corneas thinned by methods used in groups B and C to air, Balanced Salt Solution drops (Alcon, Fort Worth, Tex), or dextran solution drops. RESULTS: By 1 hour, the thinning method used in group A resulted in only three of 11 eyes achieving normal central corneal thickness. The method used in group B resulted in normal central thickness in 14 of 14 corneas and in group C, in nine of 15 corneas, at 1 hour. Once thinned by methods used in group B or C, air exposure further thinned the 30 additional corneas by 22% to 26%, Balanced Salt Solution drops thickened the corneas by 16% to 22%, and dextran solution drops stabilized the corneas with only 5% to 13% additional thinning. CONCLUSIONS: Hyperosmolar solutions were more efficient than pressure gradients in thinning the cadaver central cornea. Hydration shifts of the de-epithelialized cornea were dramatic with use of Balanced Salt Solution drops or drying and were minimized with use of hyperosmolar topical solutions.

Aged↗