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Biomedical subjects

P Erickson

Publications and source records attributed to P Erickson.

At least 19 recordsLinked to original sources
PubMed2004

Comparison of a single global item and an index of a multi-item health status measure among persons with and without diabetes in the US.

This study examined the hypothesis that a single global item can be substituted for an index of a multi-item assessment and lead to equivalent interpretative outcomes. Substitutability would be demonstrated if: (1) the two measures were strongly correlated, and regression analysis showed that the same variables accounted for variation in each measure, and (2) difference scores between multi-item and global scores were close to zero and remained so as socio-demographic and co-morbid conditions varied. A multi-item assessment was constructed by mapping items from the NHANES I Epidemiologic Follow-up Study (NHEFS), using available data for persons with and without diabetes, onto the health-status classification system of the Health Utilities Index Mark 1 (HUI), creating the NHEFS-HUI. NHEFS-HUI data, when correlated to the self-assessed health status (SAHS) item, revealed a coefficient of 0.55. Regression analyses identified 9 of 14 variables contributed to the variability of each health status index, but differences existed in which variables were significant for which measure. Five of the possible 14 difference scores for persons with diabetes and non-diabetics approached zero. Persons with diabetes had lower NHEFS-HUI scores than non-diabetics. These data were considered insufficient for demonstrating substitutability. Suggestions were made on how optimal substitutability could be achieved.

Adult↗
PubMed2001

Theoretical analysis of accommodation amplitude and ametropia correction by varying refractive index in Phaco-Ersatz.

Phaco-Ersatz is a surgical procedure for restoring accommodation in which the presbyopic crystalline lens is replaced by a flexible polymer gel in the lens capsule. We assessed the feasibility of simultaneously correcting ametropia while restoring accommodation using Phaco-Ersatz by utilizing polymer gel of the appropriate refractive index. Computation results using paraxial equations and ray tracing on two model eyes indicate that although this approach might be feasible for the hypermetrope, its usefulness for correcting myopia is limited, principally due to significant reductions in the resultant amplitude of accommodation.

Accommodation, Ocular↗
PubMed2001

Fungal skin infections in children. New developments and treatments.

Recognizing the common manifestations of pediatric fungal infections is a key part of any primary care practice. Of paramount importance is the clinical acumen of the physician. In this article, Drs Berg and Erickson discuss several types of fungal infections in children, identify tools for diagnosis, and outline the most effective options for treatment. Newer "off-label" therapies are also examined.

Administration, Cutaneous↗
PubMed2000

Altered HOX and WNT7A expression in human lung cancer.

HOX genes encode transcription factors that control patterning and cell fates. Alterations in HOX expression have been clearly implicated in leukemia, but their role in most other malignant diseases remains unknown. By using degenerate reverse transcription-PCR and subsequent real-time quantitative assays, we examined HOX expression in lung cancer cell lines, direct tumor-control pairs, and bronchial epithelial cultures. As in leukemia, genes of the HOX9 paralogous group and HOXA10 were frequently overexpressed. For HOXB9, we confirmed that elevated RNA was associated with protein overexpression. In some cases, marked HOX overexpression was associated with elevated FGF10 and FGF17. During development, the WNT pathway affects cell fate, polarity, and proliferation, and WNT7a has been implicated in the maintenance of HOX expression. In contrast to normal lung and mortal short-term bronchial epithelial cultures, WNT7a was frequently reduced or absent in lung cancers. In immortalized bronchial epithelial cells, WNT7a was lost concomitantly with HOXA1, and a statistically significant correlation between the expression of both genes was observed in lung cancer cell lines. Furthermore, we identified a homozygous deletion of beta-catenin in the mesothelioma, NCI-H28, associated with reduced WNT7a and the lowest overall cell line expression of HOXA1, HOXA7, HOXA9, and HOXA10, whereas HOXB9 levels were unaffected. Of note, both WNT7a and beta-catenin are encoded on chromosome 3p, which undergoes frequent loss of heterozygosity in these tumors. Our results suggest that alterations in regulatory circuits involving HOX, WNT, and possibly fibroblast growth factor pathways occur frequently in lung cancer.

Blotting, Western↗
PubMed2000

Gender differences in quality-adjusted survival using a Health-Utilities Index.

PURPOSE: Women live longer than men but experience high morbidity during later years. We attempt to represent life expectancy with adjustments for quality of life for men and women in the United States. DATA SOURCES: Survival estimates were obtained from Vital Statistics of the United States Life Tables. Quality-of-life data were obtained for 12,220 participants, aged 32-85 years, in the 1982-1984 National Health and Nutrition Examination Survey I Epidemiologic Follow-Up Study (NHEFS). METHOD: Using public data tapes, scores for the Health-Utilities Index (HUI) were imputed for NHEFS. These scores were calculated separately for men and women in the United States population and broken down by age. Using mortality data, the quality-adjusted life expectancy was calculated separately for men and women. RESULTS: The current life expectancy among men aged 32 years was 39.45 years. For women aged 32 years it was 44.83 years, suggesting a 5.38 female life-expectancy advantage. The life expectancy, adjusted for quality of life, was 31.8 years for men versus 33.1 years for women. Adjustment for quality of life reduced the 5.38-year female advantage to 1.3 years. CONCLUSIONS: Although women enjoy longer life expectancies than do men, this advantage is reduced when quality adjustments are used. The finding reflects high levels of morbidity among older women.

Adult↗
PubMed2000

Psychological factors and sex differences in acceptance of monovision.

49 participants, adapted to using contact lenses, completed a battery of psychological tests to examine differences between persons who were successful in wearing monovision lenses for presbyopia and those who were unsuccessful. Although visual performance and requirements strongly affect participants' satisfaction with monovision lenses, personality characteristics and visual processing styles appear to in fluence the percentage of full-time wear. Of the participants, 41% (20 of 49) ultimately rejected monovision for a variety of both visual and psychological reasons. Sex differences were evidenced in the psychological variables correlated to monovision lens wear. Analysis indicated that men scoring as introverts rejected monovision while women with difficulty perceiving a visual pattern against visual background noise had difficulty adapting to monovision and exhibited shorter wearing times.

Accommodation, Ocular↗
PubMed2000

Developing a quality management system for behavioral health care: the Cambridge Health Alliance Experience.

The rapid pace of change in the health care system presents tremendous challenges for clinicians and managers charged with the delivery of mental health and substance abuse services. Declining reimbursement, new incentive structures, and increasing competition are placing unprecedented pressure on providers to deliver care efficiently. Regulatory scrutiny, consumer dissatisfaction, and a growing awareness of gaps between actual and ideal practice have led to intensifying pressure to improve quality. Yet system change has also presented new opportunities for managing cost and quality of care. Consolidation of facilities and practices into integrated networks, developments in information systems technology, and the emergence of models to facilitate change have led to the rise of "quality management," a framework for assessing and improving clinical, operational, and financial performance within a health care organization. This article reviews some of the precipitating factors and theoretical structures underlying quality management and then, through a case study of one organization's experience, describes the implementation of a quality management program in a behavioral health care delivery system. The case study emphasizes how theoretical frameworks were operationalized and how organizational structure and process were shaped to address challenges well known in quality management, such as authority, accountability, and follow-through. A multiphase model of quality management program development is formulated and used to provide context for this program's development.

Adolescent↗
PubMed1999

DEF-3(g16/NY-LU-12), an RNA binding protein from the 3p21.3 homozygous deletion region in SCLC.

DEF-3(g16/NY-LU-12) encodes a novel RNA binding protein isolated by positional cloning from an SCLC homozygous deletion region in 3p21.3 and, in parallel, as a differentially expressed gene during myelopoiesis from FDCPmix-A4 cells. DEF-3(g16/NY-LU-12) is ubiquitously expressed during mouse embryogenesis and in adult organs while human hematopoietic tissues showed differential expression. The mouse and human proteins are highly conserved containing two RNA recognition motifs (RRMs) and other domains associated with RNA binding and protein-protein interactions. A database search identified related proteins in human, rat, C. elegans and S. pombe including the 3p21.3 co-deleted gene, LUCA15. Recombinant proteins containing the RRMs of DEF-3(g16/NY-LU-12) and LUCA15 specifically bound poly(G) RNA homopolymers in vitro. These RRMs also show similarity to those of the Hu protein family. Since anti-Hu RRM domain antibodies are associated with an anti-tumor effect and paraneoplastic encephalomyelitis, we tested sera from Hu syndrome patients with the RRMs of DEF-3(g16/NY-LU-12) and LUCA15. These were non-reactive. Thus, DEF-3(g16/NY-LU-12) and LUCA15 represent members of a novel family of RNA binding proteins with similar expression patterns and in vitro RNA binding characteristics. They are co-deleted in some lung cancers and immunologically distinct from the Hu proteins.

Adult↗
PubMed1999

The cornea swells in the posterior direction under hydrogel contact lenses.

Two mathematical models were developed to describe the topographical corneal swelling response to hydrogel contact lenses and the effect of these changes on refractive error. In one, corneal thickness changes resulted in deformation of the anterior corneal surface. In the other, the posterior surface only was deformed. Refractive error, corneal thickness and corneal shape were monitored in a sample of adapted contact lens wearers with one eye patched for 4 h while wearing a soft contact lens. The experimental data were most consistent with the model in which the posterior surface only was deformed.

Contact Lenses, Hydrophilic↗
PubMed1998

Analysis of TEL proteins in human leukemias.

Chromosomal translocations involving the human 12p13 band frequently affect the TEL gene, usually resulting in gene fusion between TEL and genes encoding proteins of various types. The most frequent 12p13 translocation is the t(12;21)(p13;q22), which recombines TEL with the AML1 gene on chromosome 21 and is frequently associated with deletion of the untranslocated TEL allele. Using antisera against different parts of TEL and against the AML1 proteins, we undertook Western blot and immunofluorescence analyses of leukemic samples with and without 12p13 abnormalities. In t(12;21) samples, TEL-AML1 was detected as several protein species in the nuclei, whereas the AML1-TEL protein, was inconsistently expressed. AML1 was found to be expressed but no normal TEL proteins were detected. A survey of the TEL proteins in a panel of human leukemic samples without t(12;21) revealed a variation in the ratio of TEL protein isoforms. We also analysed a leukemic cell line bearing a t(12;22)(p13;q11) that was found to affect the 5' untranslated (UT) region of TEL and to be associated with inactivation of the untranslocated TEL allele. No MN1-TEL fusion could be detected upon RT-PCR analysis, in contrast to the previously investigated t(12;22). Strikingly, extremely low levels of apparently normal TEL proteins, expressed from the translocated allele, were detected by Western blot analysis. These results suggest that the level of TEL expression can be important for leukemogenesis.

Adult↗
PubMed1998

Evaluation of a population-based measure of quality of life: the Health and Activity Limitation Index (HALex).

This paper briefly discusses the rationale and methods for developing and evaluating the Health and Activity Limitation Index (HALex), a generic measure of health that consists of two attributes: perceived health and activity limitation. Using a multiattribute utility scoring system, information from these attributes was combined to form a single score that represents health-related quality of life (QoL) on a 0.0-1.0 continuum. The construct and incremental validity are evaluated using data from a sample of over 40,000 adults who participated in the 1990 US National Health Interview Survey. The health state distributions for known groups, defined in terms of personal or lifestyle characteristics such as sex, age and smoking status, were comparable to those for similarly defined states that have been studied by other researchers. Of the regression models examined in this analysis, age, years of schooling and being in a high-risk group based on body mass index (BMI) were found to have the largest impact on health as measured by the HALex. Although this measure was developed to be combined with mortality data to form a quality-adjusted life year (QALY) for detecting changes in the health of the US population from 1990 to 2000, it may also be useful for inclusion in clinical studies, in particular as the national data are readily available for use as norms.

Activities of Daily Living↗
PubMed1998

Endothelial cell density and contact lens-induced corneal swelling.

PURPOSE: To determine the relationships among endothelial morphometric variables and contact lens-induced corneal swelling in a homogeneous sample of adapted contact-lens wearers. METHODS: Fifteen male subjects ranging in age from 20 to 40 years, all adapted to daily wear of hydrogel lenses, wore uniform-thickness lenses (Dk/L = 5.78) under unilaterally patched eyes for 4 h. Unpatched fellow eyes served as controls. Central corneal thickness was measured with an optical pachometer. Central endothelial images were obtained with a Topcon SP-1000 Specular Microscope and analyzed by the Topcon IMAGEnet processing system. Thickness and morphometric data were collected on test and control eyes before and after the patching sessions. RESULTS: A strong correlation (r = -0.795; p < 0.001) was found between central corneal swelling and endothelial-cell density. Correlations between swelling and the coefficient of variation in cell area (r = 0.502; p < 0.06) and between swelling and the percentage of six-sided cells (r = -0.200; p < 0.48) were not significant. Correlations among the morphometric variables were not significant. Differences in the morphometric variables between test and control eyes were not significant before or immediately after the patching sessions. CONCLUSION: Endothelial-cell density is useful in explaining differences in corneal-swelling responses to closed-eye contact-lens wear among adapted wearers, whereas morphometric variables based on cell-size variability and shape are not.

Adult↗
PubMed1998

Pre-clinical evaluation of probes to detect t(8;21) AML minimal residual disease by fluorescence in situ hybridization.

The 8;21 translocation in acute myeloid leukemia (AML) results in a consistent fusion transcript, AML1/ETO. Long-term clinical remission occurs in some patients despite incomplete eradication of AML1/ETO as demonstrated by RT-PCR, thus limiting the usefulness of this assay. An important future goal will be to determine if there is a level of minimal residual disease (MRD) in patients below which relapse is unlikely. For the detection of MRD, we have developed reagents for fluorescence in situ hybridization (FISH) that identify both derivative 8 and 21 chromosomes with a high analytical sensitivity. In t(8;21) AML cells, two fused signals were detected in addition to the normal 8 and 21 alleles. The sensitivity and specificity of this probe mixture were analyzed in cell lines and patient bone marrows. One and two randomly juxtaposed signals were observed in 2.4 and 0.04% of normal cells, respectively. However, these were easily differentiated from t(8;21) cells by the absence of signals from the normal alleles. Using as criteria the presence of two fused signals plus the normal alleles, we observed no false positives among 5,000 normal cells. The probe correctly identified 20/20 patients with t(8;21) AML and 10/10 non-t(8;21) patients. In cell dilution experiments, the analytical sensitivity of this reagent was equal to that of the X chromosome and Y chromosome alpha-satellite probes. These optimized probes should facilitate the quantitative assessment and study of MRD in t(8;21) AML.

Bone Marrow Cells↗
PubMed1996

Assessing the health of the nation. The predictive validity of a preference-based measure and self-rated health.

Health-related quality-of-life (HRQOL) measures are becoming increasingly important for evaluating the effectiveness of medical interventions and assessing the health of populations. Preference-based instruments, a subset of HRQOL measures, allow comparisons of overall health status in populations and in clinical settings, and are suitable for economic analyses; but validity studies have used selected samples, mostly examining morbidity. This study compared the performance of a preference-based instrument with self-rated health in predicting subsequent self-rated health, hospitalization, and mortality in a national cohort. A version of the Health Utility Index (HUI), constructed from questions in the 1982 to 1984 National Health and Examination Survey I Epidemiologic Follow-up Study (NHEFS), was used to develop scores for the 1982 to 1984 survey sample. The relationship between both the NHEFS-HUI and self-rated health in 1982 to 1984, and subsequent decline in self-rated health, hospitalizations, and mortality experienced by 1987 were examined using survival analyses. The analyses adjusted for sociodemographic variables (age, sex, race, education, and income), medical conditions, and smoking status reported at the 1982 to 1984 NHEFS interview. Results indicated that NHEFS-HUI and self-rated health scores were worse in older persons, persons with one or more medical conditions, African Americans, and those with less education and lower incomes. The effects of all 19 chronic conditions and smoking were reflected in lower self-rated health scores, whereas the NHEFS-HUI did not capture the effects of two of the conditions or smoking status. Both measures made independent contributions to predicting hospitalizations and mortality by 1987; in addition, the NHEFS-HUI predicted decline in subsequent self-rated health. The NHEFS-HUI also predicted health outcomes in the subgroup of those in initial excellent or very good self-rated health. A preference-based instrument demonstrated predictive validity in three relevant domains of health status outcomes across all sociodemographic groups examined in this cohort. Self-rated health was better able to capture concurrent decrements in health associated with certain chronic illnesses and smoking. It is concluded that preference-based measures capturing both functional status and health perceptions should be incorporated explicitly into national surveys to assess the health of populations.

Adult↗
PubMed1996

Effects of hydrogel lens transmissibility profiles on local corneal swelling during eye closure.

PURPOSE: To develop a unified model for describing the relations among local and regional contact lens transmissibility, topographical corneal location, and lens-induced corneal swelling under the closed eye. METHODS: Thirteen adult male subjects, all adapted to daily wear of hydrogel lenses, wore a series of hydrogel lenses under patched eyes for 4 h. Corneal swelling was determined using an optical pachometer for five sites along the vertical meridian of test corneas. Four of the test conditions involved approximately uniform (no lens or parallel lenses) oxygen barriers over the central 8 mm of the cornea. Four additional sessions involved test lenses of -6, -3, +3, and +6 D, all having a center thickness of 0.2 mm. RESULTS: For the uniform barrier conditions, corneal swelling followed a similar pattern at all sites. Swelling was greatest centrally and least at the most peripheral, 7 mm, chord. The swelling vs. lens thickness response could be closely described by a third-order polynomial. Swelling with nonuniform thickness lenses at all sites showed evidence of small thickness averaging effects. Average central corneal swelling under the nonuniform lenses could be estimated from the polynomial function by averaging lens thickness over 5.5 to 6.75 mm for minus lenses and approximately 7.75 mm for plus lenses. CONCLUSIONS: The corneal swelling response to closed eye wear of hydrogel lenses follows a well ordered course over the central 7 mm. Over the same topographical area, the degree of swelling is influenced by both local and regional lens thickness profiles.

Adult↗