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Biomedical subjects

L B Ellwein

Publications and source records attributed to L B Ellwein.

At least 37 records · Page 2Linked to original sources
PubMed1998

Visual functioning and quality of life outcomes among cataract operated and unoperated blind populations in Nepal.

BACKGROUND: Visual acuity and vision related quality of life outcomes in cataract surgery were evaluated in a population based survey in two geographic zones in Nepal. METHODS: Case finding was based on random sampling using a stratified cluster design with door to door enumeration of people aged > or = 45 years followed by eye examinations at village sites. All aphakics/pseudophakics, those with visual acuity less than 6/60 in either eye, and a sample of those with normal visual acuity were administered visual functioning (VF) and quality of life (QOL) questionnaires. RESULTS: 15% of the 159 cataract operated cases had presenting visual acuity > or = 6/18 in both eyes, 38% with best corrected visual acuity. 21% were still blind with presenting visual acuity < 6/60 in both eyes, 7% with best correction. On a 0-100 scale, mean VF and QOL scores were 87.2 and 93.9 respectively in normally sighted unoperated individuals, dropping to 15.6 and 29.5 for those severely blind (< 3/60). Among the cataract operated, mean VF and QOL scores were 47.5 and 55.4, respectively. VF and QOL scores correlated with vision status at statistically significant levels (p < 0.0001). CONCLUSION: Cataract surgery outcomes, whether measured by traditional visual acuity or by patient reported VF/QOL, are at levels many would consider unacceptably low. It is apparent that in the quest to reduce cataract blindness much more attention must be given to improving surgery outcomes.

Aged↗
PubMed1998

Cataract surgery in India: results of a 1995 survey of ophthalmologists.

The aim of this study was to investigate cataract surgery procedures and caseloads among Indian ophthalmologists in private and government practices. Members of the All India Ophthalmological Society and state ophthalmic societies were surveyed by mail questionnaire in December 1995. Out of 6,800 surveyed, 2,098 responses (31%) were received. Over 61% of the 990,249 reported cataract surgeries were carried out in private facilities with 24% of private patients receiving extracapsular cataract extraction (ECCE) and 41% ECCE with intraocular lens (IOL). Intracapsular cataract extraction remains more common in government facilities with 62% of cases. Over 85% of all surgeons reported some experience with ECCE/IOL. Surgeons operating in both private and government facilities carry an average annual caseload of 861 cataract surgeries, which is twice that of their colleagues operating exclusively in either private or government settings. Although the questionnaire response rate was low, the findings suggest that ECCE is more common in India than in generally recognized, and with the recent availability of low-cost IOLs, its popularity is rapidly expanding.

Cataract Extraction↗
PubMed1998

Estimating costs of programme services and products using information provided in standard financial statements.

The financial viability of programme services and product offerings requires that revenue exceeds expenses. Revenue includes payments for services and products as well as donor cash and in-kind contributions. Expenses reflect consumption of purchased or contributed time and materials and utilization (depreciation) of physical plant facilities and equipment. Standard financial reports contain this revenue and expense information, complemented when necessary by valuation and accounting of in-kind contributions. Since financial statements are prepared using consistent and accepted accounting practices, year-to-year and organization-to-organization comparisons can be made. The use of such financial information is illustrated in this article by determining the unit cost of cataract surgery in two hospitals in Nepal. The proportion of unit cost attributed to personnel, medical supplies, administrative materials, and depreciation varied significantly by institution. These variations are accounted for by examining differences in operational structure and capacity utilization.

Accounting↗
PubMed1997

Measurements of vision function and quality of life in patients with cataracts in southern India. Report of instrument development.

OBJECTIVE: To develop and validate vision function (VF) and quality of life (QOL) instruments in patients with cataracts in the context of large volume surgery in a developing country. MATERIALS AND METHODS: The instruments were developed using a consensus approach. One hundred patients who were undergoing cataract surgery at Aravind Eye Hospital, Madurai, India, were interviewed preoperatively and 3 and 12 months postoperatively. Standard clinical procedures were followed, including measurement of visual acuity. Between-interviewer reproducibility was measured by repeated administration of the preoperative questionnaire. Within-interviewer reproducibility was measured preoperatively in a separate study of 50 patients. RESULTS: Preoperative scores from the VF and QOL instruments were significantly associated with visual acuity (r = 0.4). Internal reliability (Cronbach alpha) was greater than .9. Both instruments showed large changes after surgery, with effect sizes of 3 or greater for most VF scales (range, 1.8-3.7) and 1 or greater for QOL scales (range, 1.0-2.2). Changes in visual acuity after surgery were correlated with changes in the VF (r = 0.44) and QOL (r = 0.41) scale scores. Between-interviewer reproducibility was acceptable (total VF scale, Spearman r = 0.7; total QOL scale; r = 0.74). The kappa values were lower for within-interviewer reproducibility. CONCLUSIONS: The study provided strong evidence for the validity, reproducibility, and responsiveness of the instruments, and for the feasibility of using them in the setting of a large volume of cataract surgery in a developing country.

Cataract↗
PubMed1996

Use of eye care services among the 1991 Medicare population.

PURPOSE: To determine the use of eye care services by type of provider (ophthalmologist, optometrist, and non-ophthalmologist physician) in the Medicare population. METHODS: As a basis for characterizing eye conditions and ophthalmic services among a population 65 years of age and older, 1991 claims from a representative 5% sample of Medicare beneficiaries were analyzed using a previously described classification scheme. Analysis was specifically conducted by type of provider as well as by the service provided. RESULTS: Almost one half of the approximately 30 million Medicare beneficiaries 65 years of age or older received eye care services in 1991, resulting in more than 35,000,000 visits (claims). Ophthalmologists provided services to 71% of this eye care population, and optometrists to 22%; 36% of this population received ophthalmic-related services from other providers, and 14% from only other providers (commonly for eye lid dermatitis and tumors). Cataract was the most common condition, accounting for 41% of visits to ophthalmologists (and 1.2 million cases of surgery), glaucoma accounted for 19% of visits, and retinal diseases for 14%. The visit percentages for optometrists are 58%, 8%, and 11%, respectively. Ophthalmic examination and evaluation accounted for 63% of the 28,000,000 paid ophthalmologists' procedures, and 58% of the 5,500,000 optometrists' procedures. CONCLUSION: Optometrists and physicians other than ophthalmologists were the sole providers of ophthalmic-related services to a large percentage of beneficiaries who received eye care in 1991. Within the universe of service provided by ophthalmologists, the majority of all care consisted of evaluation and management services as opposed to surgical procedure-based care.

Aged↗
PubMed1996

Linkage between research sponsorship and patented eye-care technology.

PURPOSE: To examine the linkage between the funding of ophthalmologic and related biomedical research and the development of patented eye-care technology using data on patents granted and the scientific literature cited by those patents. METHODS: The United States patents granted during the 20-year period from 1975 through 1994 were screened using patent office classifications and key words to identify all eye-care-related patents. Each patent's nonpatent references (references to literature other than previously granted patents) were examined, and those references to scientific papers then were reviewed to determine the authors' institutions and acknowledged funding sources. RESULTS: Major findings include the following: (1) Eye technology innovation has grown steadily, with a threefold increase in number of patents granted from 224 in 1975 to 662 in 1994. (2) The cited scientific base that supports this technology has grown even more rapidly, with a sixfold increase in the average number of nonpatent references, from fewer than 0.5 per patent in 1975 to more than 3.0 in 1994; as a result, the total number of nonpatent references has increased by a factor of 20, from 100 in 1975 to 2000 in 1994. (3) The National Eye Institute is the leading single institution in providing support for this research: 31% of all eye-care patents with science references cite papers that contain at least one acknowledgment to National Eye Institute (NEI) support; and when NEI is combined with the rest of the National Institutes of Health (NIH), 41% of the patents with science references are linked to NIH-funded research. (4) Patent science dependence, as measured by science references, is greatest for technologies related to medical treatment, surgical instruments, and intraocular lenses; moderate for diagnostic instruments and contact lens; and least for eyeglasses. CONCLUSIONS: The NIH and other sponsored vision research is of direct and increasing relevance to the growing number of US patented eye-care technologies.

Animals↗
PubMed1995

The pattern of cataract surgery in India: 1992.

Surgery for cataract blindness, a major health problem, is undergoing a rapid transition. This study characterizes cataract surgery in India in terms of practice setting and surgical procedure. A survey questionnaire was mailed in December 1992 to 4356 members of the All India Ophthalmological Society, resident in India, requesting data on cataract surgery cases within the past 12 months. Two thousand one hundred thirty-four (49%) ophthalmologists responded to the survey. Of the 1,023,070 cataract cases reported, two-thirds were private patients. Among private patients, 26.0% received extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation and 20.7% received ECCE without an IOL. Among patients operated under government auspices, 9.1% received ECCE with IOL and 22.4% received ECCE without IOL. Overall, 82.8% of active surgeons reported experience with the ECCE procedure. The cataract case load in the private sector and the frequency of ECCE, with or without IOL implantation, among both private and government-operated cases is greater than previously recognized.

Cataract Extraction↗
PubMed1995

Effect of sodium saccharin on the neonatal rat bladder.

In a two-generation bioassay, high doses of dietary sodium saccharin (NaSac) produce bladder carcinoma in rats, whereas acid saccharin (HSac) does not effect the urothelium. NaSac and HSac administered as 5% of the diet to F0 Sprague-Dawley (SD) and F344 rats, continued through to the weaned male rats for ten additional weeks. Control 3H-thymidine labeling index (LI) was high prior to and at birth (approximately 11%), declining rapidly by weaning (to < 0.2). Neither NaSac nor HSac increased proliferation through 7 days of age. NaSac increased the proliferation rate at later times, whereas HSac did not. The LI decreased to control levels in NaSac-fed rats switched to control diet after weaning and increased in control-fed rats switched to NaSac after birth or weaning. In a second experiment, 5% NaSac did not affect urothelial morphology of SD rats through 7 days. By 21 days post-birth, urothelial hyperplasia occurred in NaSac-fed rat. The LI in treated versus control was similar through gestation, with a slight difference by 7 days. LI was significantly different by 21 days post-birth, but was similar between males and females. These results provide additional evidence for the increased cell proliferative effects of NaSac during the neonatal period, but not during gestation.

Animals↗
PubMed1995

Strategic issues in preventing cataract blindness in developing countries.

Cataract blindness is a public health problem of major proportions in developing countries. Intracapsular cataract extraction with aphakic spectacles has been the standard surgical technique for restoring sight. Because of image magnification in the operated eye, however, the result in unilaterally blind patients is less than satisfactory. Fortunately, with the availability of low-cost intraocular lenses (IOL) and ophthalmologists trained in extracapsular surgery, it is now practical to intervene successfully in the unilateral case. The need for increased attention on the quality of the visual high prevalence of cataract blindness in developing countries and an increasing cataract incidence due to an aging population require substantial increases in surgical volume. The third issue relates to cost. If significant increases in surgical volume and quality of outcomes are to be realized without an increased need for external funding, service delivery must be made more efficient. The expansion of IOL surgery for unilateral blindness is a favourable trend in ensuring financial sustainability of delivery systems; patients can be operated on while still economically productive and able to pay rather than waiting for bilateral blindness and a less favourable economic and social impact. If the quality, volume, and cost issues are to be successfully addressed, operational and structural changes to eye care delivery systems are necessary. These changes can be effected through training, technology introduction, management of facilities, social marketing, organizational partnerships, and evaluation. With improved understanding of the critical factors in successful models their widespread replication will be facilitated.

Blindness↗
PubMed1993

Use of cell proliferation data in modeling urinary bladder carcinogenesis.

A multistage, probabilistic, biologically based model of carcinogenesis has been developed involving qualitative and quantitative aspects of the process. A chemical can affect the risk of cancer by directly damaging DNA and/or increasing the number of cell divisions during which errors in DNA replication can occur. Based on this model, carcinogens are classified as genotoxic versus nongenotoxic; nongenotoxic chemicals are further divided on the basis of whether or not they act through a specific cell receptor. Nongenotoxic compounds, particularly those acting through a nonreceptor mechanism, are likely to have dose and/or species-specific thresholds. This classification also implies the existence of chemicals that will be carcinogenic at high doses in animal models, but because of dose and/or mechanistic considerations, will not be carcinogenic to humans at levels of exposure. N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide (FANFT) and 2-acetylaminofluorene (AAF) are classical genotoxic bladder carcinogens that also cause proliferative effects at higher doses. Although there is an apparent no-effect level for the urinary bladder carcinogenicity of these two compounds at low doses, in reality, DNA adducts form at these low levels, and it is likely that there is a cancer effect (no threshold), but it is below the level of detection of the bioassay. These conclusions are based on studies involving multiple doses and time points in rodents, including results from the ED01. Pellets implanted directly into the rodent bladder lumen or calculi formed in the urine as a result of an administered chemical cause abrasion of the urothelium, and a marked increase in cell proliferation and cell number, and ultimately tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Acetylaminofluorene↗
PubMed1992

Simulation modeling of carcinogenesis.

A discrete-time simulation model of carcinogenesis is described mathematically using recursive relationships between time-varying model variables. The dynamics of cellular behavior is represented within a biological framework that encompasses two irreversible and heritable genetic changes. Empirical data and biological supposition dealing with both control and experimental animal groups are used together to establish values for model input variables. The estimation of these variables is integral to the simulation process as described in step-by-step detail. Hepatocarcinogenesis in male F344 rats provides the basis for seven modeling scenarios which illustrate the complexity of relationships among cell proliferation, genotoxicity, and tumor risk.

Age Factors↗
PubMed1992

Cellular proliferation and genetic events involved in the genesis of Burkitt lymphoma (BL) in immune compromised patients.

A mathematical model simulating lymphomagenesis based on the two-hit theory of carcinogenesis is presented by contrasting the biologic variables responsible for a high risk of developing Burkitt lymphoma (BL) in three immunosuppressed groups with that of nonendemic BL. In this model, the pro-B lymphocyte is considered to be the target for BL-specific translocations such as t(8;14). With repeated mitosis, the target cell pool expands in the high-risk individual, and, thereby, the opportunities for a spontaneous translocation to arise are increased. The chromosomal translocation endows the target cell with survival advantages, and, hence, lymphoma develops. Modeling results demonstrate that this increased cell proliferation is sufficient in accounting entirely for the increase in tumor prevalence. Preventing enhanced cellular proliferation by obviating immune deficiency and treating patients with agents that restore immunity or have antiviral and antiproliferative properties prior to conversion from polyclonal B-cell proliferation to monoclonal malignancy could obviate the development of BL.

B-Lymphocytes↗