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Biomedical subjects

L A Lee

Publications and source records attributed to L A Lee.

At least 37 records · Page 2Linked to original sources

Epidemiologic study of the prevalence and severity of myopia among schoolchildren in Taiwan in 2000.

BACKGROUND AND PURPOSE: A nationwide survey was performed in 2000 to determine the prevalence and severity of myopia among schoolchildren in Taiwan and to compare these findings with the results of the last survey performed in 1995. METHODS: We first divided the whole island into regions according to developmental grade scores and then sampled with the probability proportional to the size of the population within each stratum. A total of 10,889 students were enrolled, including 5,664 boys and 5,225 girls, with ages ranging from 7 to 18 years. The refractive status and corneal radius of each student were measured with an autorefractometer under cycloplegia and checked with retinoscopy. Axial length was measured using biometric ultrasound. RESULTS: The myopia rate increased from 20% at 7 years, to 61% at 12 years, and 81% at 15 years. A myopic rate of 84% was found for schoolchildren aged 16 years through 18 years. The mean refractive index reached myopic status at the age of 8, and increased to -4.12 D in girls and -3.15 D in boys at the age of 18 years. The prevalence of high myopia (> -6.0 D) at the age of 18 years was 24% in girls and 18% in boys. The increase in axial length corresponded with the progression of myopia. The anterior chamber depth was slightly deeper from 7 years to 13 years and then remained stable. The lens thickness decreased from 7 years to 11 years. After age 15, further thickening of the lens was correlated with both age and severity of myopia. However, the corneal curvature was not related to age or severity of myopia. Girls had a higher prevalence and more severe degree of myopia than boys. Children in urban areas had a higher prevalence and more severe degree of myopia than children in rural areas. CONCLUSION: The prevalence and severity of myopia in schoolchildren in Taiwan in 2000 increased compared to 1995, with the most severe increases occurring in younger age groups. Thus, preventing schoolchildren developing myopia at a young age may slow down the increase in severity of myopia in Taiwan.

Adolescent↗

Induction of ribosomal genes and hepatocyte hypertrophy by adenovirus-mediated expression of c-Myc in vivo.

Overexpression of c-Myc in immortalized cells increases cell proliferation, inhibits cell differentiation, and promotes cell transformation. Recent evidence suggests that these effects, however, do not necessarily occur when c-Myc is overexpressed in primary mammalian cells. We sought to determine the immediate effects of transient overexpression of c-Myc in primary cells in vivo by using recombinant adenovirus to overexpress human MYC in mouse liver. Mice were intravenously injected with adenoviruses encoding MYC (Ad/Myc), E2F-1 (Ad/E2F-1), or beta-galactosidase (Ad/LacZ). Transgene expression was detectable 4 days after injection. Expression of ectopic c-Myc was immediately accompanied by enlarged and dysmorphic hepatocytes in the absence of significant cell proliferation or apoptosis. These findings were not present in the livers of mice injected with Ad/E2F-1 or Ad/LacZ. Prominent hepatocyte nuclei and nucleoli were associated with the up-regulation of large- and small-subunit ribosomal and nucleolar genes, suggesting that c-Myc may induce their expression to increase cell mass. Our studies support a role for c-Myc in the in vivo control of vertebrate cell size and metabolism independent of cell proliferation.

Adenoviridae↗

Deregulation of glucose transporter 1 and glycolytic gene expression by c-Myc.

Unlike normal mammalian cells, which use oxygen to generate energy, cancer cells rely on glycolysis for energy and are therefore less dependent on oxygen. We previously observed that the c-Myc oncogenic transcription factor regulates lactate dehydrogenase A and induces lactate overproduction. We, therefore, sought to determine whether c-Myc controls other genes regulating glucose metabolism. In Rat1a fibroblasts and murine livers overexpressing c-Myc, the mRNA levels of the glucose transporter GLUT1, phosphoglucose isomerase, phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, and enolase were elevated. c-Myc directly transactivates genes encoding GLUT1, phosphofructokinase, and enolase and increases glucose uptake in Rat1 fibroblasts. Nuclear run-on studies confirmed that the GLUT1 transcriptional rate is elevated by c-Myc. Our findings suggest that overexpression of the c-Myc oncoprotein deregulates glycolysis through the activation of several components of the glucose metabolic pathway.

Animals↗

Computer crash simulations in the development of child occupant safety policies.

OBJECTIVE: To address the predictability of injury from air bag activation by use of crash simulation software. METHODS: Using current, validated crash simulation software, the effect of air bag activation on injury risk was assessed for the 6-year-old child, both restrained and unrestrained. Results were compared with those for adult occupants in similar crash scenarios. RESULTS: For the unrestrained child passenger, crash simulations predicted serious head, neck, and chest injuries with air bag activation, regardless of crash severity. For the restrained child passenger, crash simulations predicted similar severe injuries for high-severity crashes only. No serious injuries were predicted for unrestrained male adults exposed to air bags or for child passengers restrained in the rear seat for the crash scenarios simulated. CONCLUSIONS: Using current crash simulation software, this study demonstrated that the risk of air bags to school-aged children could be predicted. Our results confirmed the previously identified risks to unrestrained children and provided the first evidence that air bags, in their current design, are not beneficial to restrained children. This study illustrates that computer crash simulations should be used proactively to identify injury risks to child occupants, particularly when limited real-world data are available.

Accidents, Traffic↗

High intensity focused ultrasound effect on cardiac tissues: potential for clinical application.

High intensity focused ultrasound (HIFU) is an evolving technology with potential therapeutic applications. Utilizing frequencies of 500 kHz to 10 MHz, HIFU causes localized hyperthermia at predictable depths without injuring intervening tissue. Applications in neurosurgery, urology, oncology and, more recently, cardiology for selective cardiac conduction tissue ablation have been promising. A 'noninvasive' technique for causing localized tissue damage to relieve hemodynamic and life-threatening obstruction in patients with congenital cardiac anomalies could replace more invasive procedures. We, therefore, investigated the ability of HIFU to create lesions in mammalian cardiac tissues ex vivo. Porcine valve leaflet, canine pericardium, human newborn atrial septum, and right atrial appendage were studied. Specimens were mounted and immersed in a water bath at room temperature. Using a 1-MHz phased array transducer, ultrasound energy was applied with an acoustic intensity of 1630 W/cm(2) or 2547 W/cm(2) until a visible defect was created (duration 3 to 25 sec). Macroscopic and microscopic examination demonstrated precise defects ranging from 3 to 4 mm in diameter. No damage was identified to the surrounding tissues. Our study concluded that HIFU can create precise defects in different cardiac tissue without damage to the surrounding tissue. Further investigation is needed to assess potential clinical uses of this technology.

Animals↗

Cutaneous manifestations of neonatal lupus without heart block: characteristics of mothers and children enrolled in a national registry.

OBJECTIVE: To extend the information base on cutaneous manifestations of neonatal lupus erythematosus (NLE) with regard to maternal disease, sex of child, onset, localization, influence of UV light, prognosis, and recurrence rates in subsequent pregnancies. METHODS: Review of records from the Research Registry for Neonatal Lupus. RESULTS: The cohort includes 47 mothers (83% white) whose sera contain anti-SSA/Ro, anti-SSB/La, and/or anti-U1-ribonucleoprotein antibodies and their 57 infants (20 boys and 37 girls) diagnosed with cutaneous NLE (absent heart disease) between 1981 and 1997. At detection of the child's rash, 13 mothers were asymptomatic, 11 had an undifferentiated autoimmune syndrome (UAS), 9 had systemic lupus erythematosus (SLE), 7 Sjögren's syndrome (SS), 6 SLE/SS, and 1 rheumatoid arthritis/SS; 20 reported photosensitivity. Within 5 years, 7 asymptomatic mothers experienced disease progression: 1 developed photosensitivity, 2 SLE, 3 SS, 1 SLE/SS; in 2 mothers UAS progressed to SLE; and 2 mothers with SS developed SLE. The infant's rash often followed UV light exposure; mean age at detection was 6 weeks, and mean duration was 17 weeks. All had facial involvement (periorbital region most common) followed by the scalp, trunk, extremities, neck, and intertriginous areas. In 37, the rash resolved without sequelae, 43% of which were untreated. A quarter had residual sequelae that included telangiectasia and dyspigmentation. One child developed Hashimoto's thyroiditis, and 2 developed systemic-onset juvenile rheumatoid arthritis. Of 20 subsequent births, 7 children were healthy, 2 had congenital heart block (CHB) only, 4 CHB and skin rash, and 7 skin rash only. CONCLUSIONS: Future pregnancies should be monitored by serial echocardiograms, given the substantial risk for heart block. Affected children should be observed for later development of a rheumatic disease.

Adult↗

Buzzwords with a basis.

Learn the essential elements that characterize the concepts of motivation, mentoring, and empowerment, and explore the integral relationships between and among the three.

Attitude of Health Personnel↗

Biventricular repair for aortic atresia or hypoplasia and ventricular septal defect.

OBJECTIVE: Aortic valve atresia or hypoplasia can present with a ventricular septal defect and a normal mitral valve and left ventricle. These patients may be suitable for biventricular repair, although the optimal initial management strategy remains unknown. METHODS: From January 1991 through March 1999, 20 patients with aortic atresia or hypoplasia and ventricular septal defect underwent operation with the intent to achieve biventricular repair. Aortic atresia was present in 7 patients, and aortic valve hypoplasia was present in 13 patients. Among those patients with aortic hypoplasia, Z-scores of the aortic valve anulus ranged from -8.8 to -2.7. Associated anomalies included interrupted aortic arch (n = 12 patients), coarctation (n = 6 patients), aortopulmonary window (n = 1 patient), and heterotaxia (n = 1 patient). Nine patients were staged with an initial Norwood procedure followed by biventricular repair in 8 patients. One patient awaits biventricular repair after a Norwood procedure. The conditions of 11 patients were corrected with a single procedure. RESULTS: Among the 9 patients who underwent staged repair, there were no deaths after the Norwood procedure and 1 death after biventricular repair. For the 11 patients who underwent a primary biventricular repair, there was 1 early death and 2 late deaths from noncardiac causes. Follow-up ranged from 1 to 85 months (mean, 28 months). Actuarial survival for the entire group was 78% +/- 10% at 5 years and was not significantly different between staged repair (89%) and primary biventricular repair (73%). CONCLUSIONS: Both primary and staged biventricular repair for patients with aortic atresia or hypoplasia and ventricular septal defect may be performed with good late survival. Refinements in technique of conduit insertion and arch reconstruction have resulted in primary biventricular repair becoming our preferred approach.

Actuarial Analysis↗

The clinical spectrum of anti-Ro-positive cutaneous neonatal lupus erythematosus.

BACKGROUND: Cutaneous neonatal lupus erythematosus (NLE) is an uncommon disease described mainly through isolated case reports. OBJECTIVE: Our purpose was to examine the cutaneous spectrum, clinical associations, and course of disease in babies with anti-Ro-positive NLE. METHODS: This is a retrospective case series evaluation of newborns with anti-Ro-positive NLE seen at a single ambulatory care university center over a 20-year period. Cases were drawn from a population of 3.2 million. Follow-up was at least 3 years. RESULTS: Four boys and 14 girls were included in our evaluation. Distribution of skin lesions in 18 babies was as follows: face, 17; periorbital "owl-eye" or "eye mask" facial rash, 14; scalp, 15; arms and legs, 13; trunk and groin, 6. Crusted lesions were predominant in 3. Photosensitivity was seen in 12, and features of cutis marmorata telangiectasia congenita were observed in 4. In 17 neonatal lupus was not suspected until the dermatology consultation. Noncutaneous manifestations included thrombocytopenia in 4, cholestatic hepatitis in 3, and congenital heart block in 3. Four patients had residual telangiectasia that persisted for 3 or more years but eventually cleared in 2 patients. Three babies had dyspigmentation that spontaneously cleared within 22 months. None had atrophy or scarring. CONCLUSION: Periorbital, scalp, and extremity lesions are common in cutaneous NLE. Crusted lesions predominated in male infants. In children selected by cutaneous involvement, thrombocytopenia and hepatic disease were present as frequently as cardiac disease and occurred more frequently in male babies with crusted skin lesions. Children with cutaneous NLE should be evaluated for hematologic and hepatic as well as cardiac involvement.

Antibodies, Antinuclear↗

Photosensitivity diseases: cutaneous lupus erythematosus.

Ultraviolet radiation plays an important role in the induction of lesions in many patients with cutaneous lupus. In the photosensitive subset of lupus, subacute cutaneous lupus, the effects of ultraviolet radiation likely act in concert with specific autoantibodies, particularly anti-Ro-related autoantibodies, to produce lesions. Potential effects of ultraviolet radiation on the induction of cutaneous lupus, and the potential interplay of specific autoantibodies with ultraviolet radiation are discussed. The steps involved in the induction of cutaneous lupus lesions by ultraviolet radiation have not been fully elucidated. Recent advances in phototesting and analysis of the genetics of lupus should clarify the events leading to photosensitive cutaneous lupus lesions.

Animals↗

Characterization of an autoantigen associated with chronic ulcerative stomatitis: the CUSP autoantigen is a member of the p53 family.

A unique clinical syndrome has been described in which patients have chronic oral ulceration and autoantibodies to nuclei of stratified squamous epithelium. We have characterized the autoantibodies from patients sera and found that the major autoantigen is a 70 kDa epithelial nuclear protein. Sequencing of the cDNA for this protein, chronic ulcerative stomatitis protein, revealed it to be homologous to the p53 tumor suppressor and to the p73 putative tumor suppressor, and to be a splicing variant of the KET gene. The p53-like genes, p73 and the several KET splicing variants, are recently described genes of uncertain biologic and pathologic significance. This study provides the first clear association of a p53-like protein with a disease process.

Autoantigens↗

Epidemiologic study of ocular refraction among schoolchildren in Taiwan in 1995.

PURPOSE: In order to understand and update the prevalence of myopia in Taiwan, a nationwide survey was performed in 1995. METHODS: We stratified the cluster sampling by developmental grading of the city, using a size proportional to the population. Two cities were randomly selected from each city grading. The total number of students enrolled was 11,178, including 5,676 boys and 5,502 girls. The refractive status and corneal radius of each student were measured with an autorefractometer under cycloplegia and checked with retinoscopy. Axial length was measured with biometric ultrasound. RESULTS: The myopic rate was from 12% at the age of 6, it increased to 56% at the age of 12, and then to 76% at the age of 15. A myopic rate of 84% was found for the age range of 16 to 18. The prevalence of high myopia (over -6.0 D) at the age of 18 was 20% in girls and 12% in boys. The mean refractive status became myopic at the age of 9, then increased to -3.92 D in girls and -2.71 D in boys at the age of 18. The increase of axial length is correspondent with the progression of myopia. The anterior chamber depth (ACD) was deeper with age and the severity of myopia, whereas the corneal curvature remained unchanged. The lens thickness became thinner from age 7 to 13, then it became thicker with age and the severity of myopia after age 15. The prevalence and degree of myopia in girls was more severe than in boys. CONCLUSIONS: The prevalence of myopia in Taiwan increased year by year. The increase in severity and prevalence of high myopia may be due to earlier onset.

Adolescent↗

Treatment in Kenyan rural health facilities: projected drug costs using the WHO-UNICEF integrated management of childhood illness (IMCI) guidelines.

Guidelines for the integrated management of childhood illness (IMCI) in peripheral health facilities have been developed by WHO and UNICEF to improve the recognition and treatment of common causes of childhood death. To evaluate the impact of the guidelines on treatment costs, we compared the cost of drugs actually prescribed to a sample of 747 sick children aged 2-59 months in rural health facilities in western Kenya with the cost of drugs had the children been managed using the IMCI guidelines. The average cost of drugs actually prescribed per child was US$ 0.44 (1996 US$). Antibiotics were the most costly component, with phenoxymethylpenicillin syrup accounting for 59% of the cost of all the drugs prescribed. Of the 295 prescriptions for phenoxymethylpenicillin syrup, 223 (76%) were for treatment of colds or cough. The cost of drugs that would have been prescribed had the same children been managed with the IMCI guidelines ranged from US$ 0.16 per patient (based on a formulary of larger-dose tablets and a home remedy for cough) to US$ 0.39 per patient (based on a formulary of syrups or paediatric-dose tablets and a commercial cough preparation). Treatment of coughs and colds with antibiotics is not recommended in the Kenyan or in the IMCI guidelines. Compliance with existing treatment guidelines for the management of acute respiratory infections would have halved the cost of the drugs prescribed. The estimated cost of the drugs needed to treat children using the IMCI guidelines was less than the cost of the drugs actually prescribed, but varied considerably depending on the dosage forms and whether a commercial cough preparation was used.

Child Health Services↗

Alendronate-associated esophageal injury: pathologic and endoscopic features.

Ingestion of alendronate sodium (Fosamax) by osteoporotic patients can be associated with esophagitis and esophageal ulcer. Alendronate can damage the esophagus both by toxicity from the medication itself and by nonspecific irritation secondary to contact between the pill and the esophageal mucosa, similar to other cases of "pill esophagitis." Despite its wide use, the histologic appearances of alendronate-associated esophageal ulceration have not been previously described in detail, nor is this type of medication-induced injury commonly appreciated by pathologists when evaluating biopsies from ulcer sites. We report a series of 10 patients who experienced erosive/ulcerative esophagitis while ingesting alendronate, and describe the associated endoscopic and pathologic features. Biopsies from all patients showed inflammatory exudate and inflamed granulation tissue as characteristic of any ulcer site. Polarizable crystalline foreign material was present in six of 10 biopsies (60%). Multinucleated giant cells within the inflammatory exudate were present near this crystalline foreign material in three of 10 biopsies (30%). Adjacent squamous epithelium typically showed active inflammation and a reactive appearance with enlarged, hyperchromatic nuclei. Multinucleated squamous epithelial giant cells were present in two of 10 cases (20%). Microorganisms were unusual; scattered fungi and/or viral inclusions were present in only two of 10 biopsies (20%). Recognition of alendronate-associated erosive or ulcerative esophagitis, particularly in postmenopausal women, and communication of this possibility to the clinician can improve patient care.

Aged↗

Subacute and non-acute casemix in Australia.

The costs of subacute care (palliative care, rehabilitation medicine, psychogeriatrics, and geriatric evaluation and management) and non-acute care (nursing home, convalescent and planned respite care) are not adequately described by existing casemix classifications. The predominant treatment goals in subacute care are enhancement of quality of life and/or improvement in functional status and, in non-acute care, maintenance of current health and functional status. A national classification system for this area has now been developed--the Australian National Sub-Acute and Non-Acute Patient Classification System (AN-SNAP). The AN-SNAP system, based on analysis of over 30,000 episodes of care, defines four case types of subacute care (palliative care, rehabilitation, psychogeriatric care, and geriatric evaluation and management and one case type of non-acute care (maintenance care), and classifies both overnight and ambulatory care. The AN-SNAP system reflects the goal of management--a change in functional status or improvement in quality of life--rather than the patient's diagnosis. It will complement the existing AN-DRG classification.

Aged↗