Biomedical subjects

D J Lee

Publications and source records attributed to D J Lee.

At least 145 records · Page 8Linked to original sources

PubMed1997

Major depressive disorder, depressive symptoms, and bilateral hearing loss in hispanic adults.

Studies in non-Hispanic whites have documented higher rates of hearing loss in adults with depression versus those without depression. Data from the Hispanic Health and Nutrition Examination Survey were used to investigate associations between depression and bilateral hearing loss in Cuban-American, Mexican-American, and Puerto Rican adults 20-74 years of age. Pure tone thresholds were calculated by averaging thresholds obtained at 500, 1000, and 2000 Hz separately for each ear. Hearing loss was defined as bilateral pure tone average threshold levels greater than 25 db. Lifetime history of a major depressive episode was assessed by the Diagnostic Interview Schedule, and depressive symptoms were assessed by the Center for Epidemiologic Studies Depression Schedule. Prevalence of overall hearing loss was consistently lower in Hispanics with a history of major depressive disorder than among those without such a history. Odds of hearing impairment was significantly greater among Puerto-Ricans reporting more depressive symptoms versus fewer symptoms. However, no such associations were found among Mexican-Americans or Cuban-Americans. In conclusion, despite the findings in Puerto Ricans with depressive symptoms short of major depression, hearing impaired Hispanics overall do not appear at increased risk of major depressive disorder.

Adult↗

PubMed1997

Epidemiology of hepatitis B vaccine acceptance among urban paramedics and emergency medical technicians.

BACKGROUND: The epidemiologic pattern of hepatitis B vaccination acceptance has not been thoroughly examined in medical first responders. METHODS: A blood-borne pathogen questionnaire was administered to 255 paramedics and emergency medical technicians (EMTs) in a large, urban fire department. RESULTS: The overall prevalence of hepatitis B vaccination was 78%. The most frequently cited reason for not getting vaccinated was fear of contracting the hepatitis B virus from the vaccination (26%). Vaccination scheduling difficulties (23%) and lack of time to get vaccinated (20%) were also cited. Increased age, being an EMT, and not having obtained the rank of officer were independently and significantly associated with not having been vaccinated. CONCLUSIONS: Educational campaigns for medical first responders are needed to increase vaccination compliance, with a special emphasis on older workers and EMTs. Administrative barriers, such as vaccination scheduling difficulties, should also be addressed.

Adult↗

PubMed1997

Assessment of mitral annulus velocity by Doppler tissue imaging in the evaluation of left ventricular diastolic function.

OBJECTIVES: This study assessed the clinical utility of mitral annulus velocity in the evaluation of left ventricular diastolic function. BACKGROUND: Mitral inflow velocity recorded by Doppler echocardiography has been widely used to evaluate left ventricular diastolic function but is affected by other factors. The mitral annulus velocity profile during diastole may provide additional information about left ventricular diastolic function. METHODS: Mitral annulus velocity during diastole was measured by Doppler tissue imaging (DTI) 1) in 59 normal volunteers (group 1); 2) in 20 patients with a relaxation abnormality as assessed by Doppler mitral inflow variables (group 2) at baseline and after saline loading; 3) in 11 patients (group 3) with normal diastolic function before and after intravenous nitroglycerin infusion; and 4) in 38 consecutive patients (group 4) undergoing cardiac catheterization in whom mitral inflow velocity and tau as well as mitral annulus velocity were measured simultaneously. RESULTS: In group 1, mean +/- SD peak early and late diastolic mitral annulus velocity was 10.0 +/- 1.3 and 9.5 +/- 1.5 cm/s, respectively. In group 2, mitral inflow velocity profile changed toward the pseudonormalization pattern with saline loading (deceleration time 311 +/- 84 ms before to 216 +/- 40 ms after intervention, p < 0.001), whereas peak early diastolic mitral annulus velocity did not change significantly (5.3 +/- 1.2 cm/s to 5.7 +/- 1.4 cm/s, p = NS). In group 3, despite a significant change in mitral inflow velocity profile after nitroglycerin, peak early diastolic mitral annulus velocity did not change significantly (9.5 +/- 2.2 cm/s to 9.2 +/- 1.7 cm/s, p = NS). In group 4, peak early diastolic mitral annulus velocity (r = -0.56, p < 0.01) and the early/late ratio (r = -0.46, p < 0.01) correlated with tau. When the combination of normal mitral inflow variables with prolonged tau (> or = 50 ms) was classified as pseudonormalization, peak early diastolic mitral annulus velocity < 8.5 cm/s and the early/late ratio < 1 could identify the pseudonormalization with a sensitivity of 88% and specificity of 67%. CONCLUSIONS: Mitral annulus velocity determined by DTI is a relatively preload-independent variable in evaluating diastolic function.

Adult↗

PubMed1997

Slow release from a coated sphere with slight deformations of coating film and drug matrix.

This paper, a continuation of our previous work, is a presentation of the effects of slight deformations of both the coating film and the drug matrix on the concentration distributions and the slow release characteristics of a coated drug particle. The coated particle shape, in practice, is not perfectly spherical. With restriction of the deformation shape functions considered, it is noted that if the deformation is slight or if only the average release rate is of interest, the effects of shape deformation are secondary. Otherwise, the shape deformation can have a significant effect on the concentration profiles and/or the release rate from different parts of the particle surface. The deformations of both coating film and the drug matrix could introduce a greater deviation from the spherical case than those considering only coating film or drug matrix shape deformation.

Delayed-Action Preparations↗

PubMed1997

New agents, the circle system and short procedures.

Sevoflurane, desflurane and isoflurane were compared using a circle system in 97 patients undergoing short surgical procedures. Using initial high flows, the time intervals to equilibration between inspired and end-expired agent concentrations were measured; equilibration was defined as FE/FI = 0.8. The mean (SD) times obtained for sevoflurane, desflurane and isoflurane were 8.2 (2.1) min, 3.8 (0.7) min and 19.7 (6.5) min, respectively. These times were significantly different from each other (p < 0.0001). After equilibration total flow were reduced to 500 ml.min-1; at these flows the initial decline in end-expired agent concentration was minimal with desflurane, intermediate with sevoflurane and greatest with isoflurane. Both desflurane and sevoflurane are appropriate for efficient use of the circle system during short anaesthetics.

Adult↗

PubMed1997

Sociodemographic and educational correlates of hearing loss in Hispanic children.

Sociodemographic and educational correlates of hearing loss were examined in Cuban-American, Mexican-American and Puerto Rican children 6-19 years of age. Logistic regression analyses indicated a greater risk of bilateral hearing loss among children living in crowded housing conditions or without health insurance, as well as among those who were below expected school grade level and whose parents reported low educational attainment levels. However, the strengths of these associations were small to moderate in magnitude and were not always consistent across the ethnic subgroups. These findings provide some evidence that hearing-impaired Hispanic children are more likely to reside in economically disadvantaged families and to be below their expected school grade level.

Adolescent↗

PubMed1997

A case of biliary cystadenocarcinoma.

Biliary cystadenocarcinoma is a very rare cystic tumor that arises in the liver or, less frequently, in the extrahepatic biliary system. It has been shown to arise in congenital liver cysts, bile ducts, biliary cystadenoma, in the context of fibropolycystic disease and in the hepatoduodenal ligament. Common presenting symptoms include an abdominal mass, local pain, nausea, jaundice, fever or occasional ascites. Some patients are asymptomatic, the lesion being an incidental finding at autopsy or surgery. Approximately 50 cases have been reported in the literature. We report a case of biliary cystadenocarcinoma in a 63-year-old man with a review of the literature.

Biliary Tract Neoplasms↗

PubMed1997

Impact of chromosome 14q loss on survival in primary head and neck squamous cell carcinoma.

We screened 73 primary head and neck squamous cell carcinoma (HNSCC) specimens for loss of heterozygosity (LOH) on chromosome 14q. Analysis of 20 polymorphic microsatellite markers identified 29 (40%) HNSCCs exhibiting LOH of 14q in at least one locus. Six tumors had probable monosomy of 14q, displaying allelic loss for all informative markers tested, and 23 demonstrated partial losses on 14q. Fine mapping with 1-10 additional markers revealed two poorly defined regions of loss (4-7 cM) at 14q13-21 and 14q31-32.1 in seven tumors. In 53 patients with previously untreated tumors treated with curative intent, LOH of 14q in these tumors correlated with poor survival. Compared to patients with tumors that retain heterozygosity of 14q, those with 14q LOH had a 3-fold increased risk of death in multivariate analysis (hazards ratio, 3.2; 95% confidence interval = 1.2-8.4). These data have confirmed a high frequency of chromosome 14q loss in HNSCC and suggest that LOH of any region on chromosome 14q is an indicator of poor outcome.

Adult↗

PubMed1996

p53 mutation and locoregional treatment failure in head and neck squamous cell carcinoma.

BACKGROUND: The p53 gene (also known as TP53) may be the most common genetic target involved in the malignant transformation of human cells. Direct sequence analysis has demonstrated that alteration of this gene occurs in approximately 45% of head and neck squamous cell carcinomas. The consequences of p53 mutations in these cancers with respect to tumor behavior and patient survival have not been rigorously determined. PURPOSE: We evaluated the implications of p53 mutations in relation to the control of locoregional disease and overall survival following radiation therapy. METHODS: Data from 110 consecutive patients with invasive disease who were treated with primary radiation therapy (given with curative intent) or with adjuvant radiation therapy (following complete surgical extirpation of gross disease) were included in the analysis. A 1.8-kilobase fragment of the p53 gene encompassing exons 5-9 was amplified from the DNA of stored (frozen) tumor specimens; the amplified DNA was cloned and sequenced by use of standard techniques. Overall survival and locoregional disease-free survival after the completion of radiation therapy were estimated by the Kaplan-Meier method; survival comparisons were made by use of the logrank test or proportional hazards regression models. Reported P values are two-sided. RESULTS: Fortyeight (44%) of the 110 tumors had cells bearing p53 mutations. The risk of locoregional recurrence following either primary or adjuvant radiation therapy was significantly greater (i.e., the time to recurrence was shorter) for patients whose tumors contained mutant p53 genes (univariate model hazard ratio [HR] for p53 mutation versus wild-type = 2.2; 95% confidence interval [CI] = 1.2-4.1; P = .02). The presence of regional lymph node metastases (presence versus absence, HR = 2.0; 95% CI = 1.0-4.2; P = .05) and treatment type (primary radiation therapy versus surgery plus adjuvant radiation therapy, HR = 2.3; 95% CI = 1.2-4.3; P = .01) were also associated with greater risks of locoregional failure. The presence of p53 mutations and lymph node metastases and treatment with primary, as opposed to adjuvant, radiation therapy remained significant risk factors in multivariate regression analysis. No relationship was demonstrated between p53 status and overall survival (mutant versus wild-type, HR = 1.1; 95% CI = 0.6-2.1; P = .66); however, a relationship was shown for tumor stage and overall survival (stages III and IV [more advanced] versus stages I and II [less advanced], HR = 3.3; 95% CI = 1.0-10.8; P = .05). Mutation of the p53 gene was not associated with patient age, sex, tumor stage, primary tumor site, regional lymph node status, degree of tumor cell differentiation, or treatment method. CONCLUSIONS: Mutation of the p53 gene is associated with an increased risk of locoregional failure in patients with invasive head and neck squamous cell carcinoma who are treated with radiation therapy.

Carcinoma, Squamous Cell↗

PubMed1996

Gene vaccination with naked plasmid DNA: mechanism of CTL priming.

The injection of naked plasmid DNA directly into the muscle cells of mice has been shown to induce potent humoral and cellular immune responses. The generation of a cytotoxic T lymphocyte (CTL) response after plasmid DNA injection may involve the presentation of the expressed antigen in the context of the injected myocytes' endogenous major histocompatibility (MHC)-encoded class I molecules or may use the MHC molecules of bone marrow-derived antigen presenting cells (APC) which are capable of providing co-stimulation as well. To resolve which cell type provides the specific restricting element for this method of vaccination we generated parent-->F1 bone marrow chimeras in which H-2bxd recipient mice received bone marrow that expressed only H-2b or H-2d MHC molecules. These mice were injected intramuscularly with naked plasmid DNA that encoded the nucleoprotein from the A/PR/8/34 influenza strain, which as a single antigen has epitopes for both H-2Db and H-2Kd. The resulting CTL responses were restricted to the MHC haplotype of the bone marrow alone and not to the second haplotype expressed by the recipient's myocytes. The role of somatic tissues that express protein from injected plasmids may be to serve as a reservoir for that antigen which is then transferred to the APC. Consequently, our data show that the mechanism of priming in this novel method for vaccination uses the MHC from bone marrow-derived APC, which are efficient at providing all of the necessary signals for priming the T cell.

Animals↗

PubMed1996

Prevalence of childhood hearing loss. The Hispanic Health and Nutrition Examination Survey and the National Health and Nutrition Examination Survey II.

Comparative analysis of the epidemiology of childhood hearing loss was undertaken among African-American, Hispanic-American, and non-Hispanic white children. Audiometric data on children aged 6-19 years were obtained from 688 African Americans, 330 Cuban Americans, 2,602 Mexican Americans, 1,025 Puerto Ricans, and 3,243 non-Hispanic whites who participated in either the National Health and Nutrition Examination Survey II, 1976-1980, or the Hispanic Health and Nutrition Examination Survey, 1982-1984. Hearing loss was defined as a pure-tone decibel hearing threshold level (averaged over 500, 1,000, and 2,000 Hz) greater than 15 in the ear with the best response. The prevalence (per 1,000) of bilateral hearing loss was 17.0 for African-American, 68.3 for Cuban-American, 27.6 for Mexican-American, 57.7 for Puerto Rican, and 15.5 for non-Hispanic white children. Differences in prevalence by ethnicity/race diminished when a more stringent definition of hearing loss (i.e., moderate or greater than 30 dB hearing threshold level) was used. There were no adolescent African-American males aged 16-19 years who had a hearing loss. After adjustment for age, the odds of hearing loss was significantly greater in males than in females only in non-Hispanic whites (odds ratio = 2.2; 95% confidence interval 1.6-3.3). On the basis of 1993 census population estimates in the United States, over 819,000 children aged 6-19 years have some degree of hearing impairment, and over 216,000 of these children have moderate or greater hearing impairment.

Adolescent↗

PubMed1996

Outpatient interstitial thermoradiotherapy.

BACKGROUND: Hyperthermia enhances the cytocidal effect of ionizing radiation. Several pilot studies demonstrated that the combination of interstitial hyperthermia and interstitial radiotherapy (interstitial thermoradiotherapy) is safe and effective. However, these studies mainly utilized low dose rate brachytherapy, and therefore, required hospitalization. With the availability of median or high dose rate brachytherapy devices, we piloted a study to evaluate the feasibility, toxicity and efficacy of interstitial thermoradiotherapy performed in an outpatient setting. METHODS: Between 1989 and 1993, 27 patients with a diagnosis of carcinoma of the head and neck region (n = 23), carcinoma of the breast (n = 3), or malignant melanoma (n = 1) received 1 or 2 sessions of interstitial thermoradiotherapy. Median patient age was 66 years (range: 37-83 years). Treatment consisted of 60 minutes of 915 MHz microwave interstitial hyperthermia, followed by iridium-192 seed implants, either by Micro-Selectron HDR (10-12 Gray [Gy] in 8.5-21 minutes) or high activity (5-8 mCi per seed) seeds (10-15 Gy in 2-4 hours). In addition to interstitial temperature measurements, a real-time thermal camera was used to monitor the surface temperature spatial distribution. power supply and/or position of interstitial microwave applicators was adjusted when appropriate. All but one patient also received external beam irradiation prior to implants. RESULTS: Patients tolerated treatments well although 16 (59%) of them required analgesics during hyperthermia sessions. Skin blisters or ulcerations occurred in only 6 (22%), and all but 2 healed. Complete response occurred in 24 patients (89%), partial in 3 (11%). With a median follow up of 16 months (range: 3-43 months), the 2-year actuarial local control rate was 74%. CONCLUSIONS: The results of this study indicate that outpatient interstitial thermoradiotherapy is convenient, safe, and efficacious for treating human neoplasms.

Actuarial Analysis↗

PubMed1996

Type A behavior pattern and change in blood pressure from childhood to adolescence. The Minneapolis Children's Blood Pressure Study.

The association of the Type A behavior pattern with change in blood pressure was examined in a multiethnic sample of schoolchildren. Blood pressure was assessed in 1978 (mean age = 8 years) and approximately biannually thereafter through 1987-1990, when a post-high school screening was completed. The Matthews Youth Test for Health (MYTH) was completed by the teachers of a sample of participants in 1982 (n = 502). The Jenkins Activity Survey (JAS) was completed by all adolescents who participated in the post-high school screening (n = 816). Males were more likely to be classified as Type A than were females by the JAS and the MYTH. Type A status was not associated cross-sectionally with elevated blood pressure. JAS-assessed Type B males had significantly higher mean post-high school fourth- and fifth-phase diastolic blood pressures than did Type A males (70.2 mmHg vs. 68.2 mmHg, p < 0.05; 68.1 mmHg vs. 65.2 mmHg, p < 0.01). JAS-assessed Type A/B status was not associated with 10-year change in blood pressure. MYTH-determined Type B females tended to have higher diastolic blood pressures than MYTH-determined Type A females throughout the 10-year study period. Results from this study did not confirm the hypothesis that Type A participants would have significantly higher blood pressures than Type B participants at the time of Type A assessment; nor did they confirm the hypothesis that Type A participants would exhibit greater increases in blood pressure than Type B participants over a 10-year period.

Adolescent↗

PubMed1996

Open lung biopsy in pediatric patients on extracorporeal membrane oxygenation.

Open lung biopsy has proven beneficial in the treatment of life-threatening pulmonary diseases. Its safety and efficacy in infants and children placed on extracorporeal membrane oxygenation (ECMO) for severe respiratory failure is not known. The authors reviewed eight cases (4 neonates, 3 infants, 1 child) who underwent open lung biopsy while on ECMO. The primary diagnoses were pneumonia (4), lymphoma (1), primary pulmonary hypertension (1), and complex congenital heart disease (2). The patients underwent biopsy after they had been on ECMO an average of 9.6 days (range, 1 to 14 days). Biopsy results confirmed the clinical diagnosis in five patients, two of whom had irreversible alveolar destruction resulting in ECMO withdrawal. Three patients had pathological diagnoses, which resulted in major therapy revisions (1 fungal infection and 2 noninfectious lesions that required steroid treatment). The overall average duration of ECMO treatment was 16.3 days (range, 10 to 24 days). Three patients were weaned successfully from ECMO, but only one infant survived to discharge. One nonlethal bleeding complication occurred after biopsy. Open lung biopsy is well tolerated during ECMO. It accurately determines pulmonary pathology and provides valuable prognostic information. Earlier biopsy for patients whose diagnoses are uncertain or who are not responding to ECMO may improve the mortality rate for this high-risk group.

Biopsy↗

PubMed1996

Efficiency of a circle system for short surgical cases: comparison of desflurane with isoflurane.

Patients undergoing short surgical procedures but requiring ventilation of the lungs were allocated randomly to receive either desflurane or isoflurane by circle absorption system, initially at a high fresh gas flow. The inspired and expired concentrations of the volatile agent were measured and the fresh gas flows reduced to low flow (500 ml min-1 total when FE/FI = 0.8), as measured on a multigas analyser. In patients receiving desflurane (n = 32), the median time at which flows were reduced was 5 min (interquartile range (IQR) 1 min) while with isoflurane (n = 32), the median time was 19 (IQR 12) min. After the reduction in flow, expired concentrations of volatile agent decreased in both groups. In the isoflurane group the concentration continued to decrease during anaesthesia. In the desflurane group the initial decrease was followed by a slow recovery. We conclude that the circle system can be used efficiently for short anaesthetics using desflurane.

Adult↗

PubMed1996

Sociodemographic correlates of hearing loss and hearing aid use in Hispanic adults.

We examined sociodemographic correlates of hearing loss and hearing aid use in adult Hispanics using data from the Hispanic Health and Nutrition Examination Survey. After adjustment for age and gender, odds ratios (ORs) of hearing impairment for non-married vs married participants were 1.6 [95% confidence interval (CI) = 1.0-2.5] for Mexican-Americans and 2.2 (95% CI = 1.2-4.2) for Puerto Ricans. ORs ranged from 1.6 to 3.2 for unemployed vs employed, and from 1.7 to 2.1 for uninsured vs insured Hispanics. For Mexican-Americans, the OR of hearing aid use for those living below vs above the poverty line was 9.1 (95% CI = 1.1-100.0). These results are consistent with those reported for other ethnic groups.

Adult↗

PubMed1996

Bloodborne pathogens risk and precautions among urban fire-rescue workers.

Health care workers are exposed to various infectious agents that can lead to disease transmission during patient care. Emergency first-responders, paramedics, and emergency medical technicians (EMTs) are a subgroup of health care workers particularly at risk for occupational exposure to bloodborne pathogens. The Centers for Disease Control and Prevention has recommended universal precautions to prevent occupational transmission of bloodborne pathogens among health care workers. This cross-sectional study evaluates risks and behaviors for occupational exposure to bloodborne pathogens among urban paramedics and EMTs in Dade County, Florida. Reported exposure via multiple routes was common, especially among paramedics. Knowledge of universal precautions was high, but reported practices were suboptimal because of inadequate information, as well as logistical and access issues. Additional research, administrative effort, and regulation are needed to increase the application of universal precautions in the prehospital setting.

Adult↗

PubMed1996

Hypoxic sensitizer and cytotoxin for head and neck cancer.

Tumour hypoxia is well recognised as a major factor contributing to radioresistance. This article examines the role of hypoxia in influencing the treatment outcome following radiotherapy (RT), and reviews the rationale and results of clinical trials that utilise hypoxic sensitizers or cytotoxins in the treatment of head and neck carcinoma. Histologic evidence for tumour hypoxia in human neoplasms was first reported in 1955. Since then, direct measurement by microelectrodes has revealed heterogeneity in intratumoural oxygen concentrations, and low oxygen concentrations are associated with poor local-regional control by RT. These findings coupled with the result of nuclear imaging studies employing radiolabelled imidazoles, provide strong evidence for the existence of tumour hypoxia which influences RT treatment outcome. Hyperbaric oxygen (HBO) trials for head and neck cancer, conducted in the early 1970s, demonstrated that HBO improved local control and survival rates in patients with head and neck cancer receiving radiotherapy (RT). Since the mid-1970s, clinical research in overcoming tumour hypoxia was mainly centred on the use of nitro-imidazoles as hypoxic cell sensitizers. However, the results from several major clinical trials remain inconclusive. Specifically, the Radiation Therapy Oncology Group (RTOG) misonidazole head and neck trial (298 patients) showed no benefit. The Danish misonidazole trial (626 patients) showed no overall benefit, however positive results were observed in a subgroup (304 pharyngeal cancer patients). Although the European Organisation for Research and Teaching of Cancer (EORTC) misonidazole trial with hyperfractionated RT showed no benefit, the Danish nimorazole trial demonstrated an overall benefit in survival as well as local control. The European etanidazole (ETA) trial (374 patients) showed no advantage of adding the drug to RT. The RTOG ETA trial (504 patients) showed no global benefit. However, positive results were observed in a subset of patients with early nodal disease (197 patients). In addition, a recent meta-analysis by Overgaard, utilising pooled results in the literature demonstrated that modification of tumour hypoxia significantly improved local-regional control in head and neck cancers with an odds ratio of 1.23 (95% confidence limits 1.09 to 1.37). Hypoxic cytotoxins, such as tirapazamine, represent a novel approach in overcoming radioresistant hypoxic cells. Tirapazamine is a bioreductive agent which, by undergoing one electron reduction in hypoxic conditions, forms cytotoxic free radicals that produce DNA strand breaks causing cell death. In vitro and in vivo laboratory studies demonstrate that tirapazamine is 40 to 150 times more toxic to cells under hypoxic conditions as compared to oxygenated conditions and that tirapazamine is superior to ETA in enhancing fractionated irradiation in mouse SCCVII and other tumour types with an enhancement ratio of 1.5 to 3.0. Phase I studies demonstrated that therapeutic doses of tirapazamine can be given safely. A multi-institutional phase II trial using tirapazamine with concurrent RT for head and neck cancer is now in progress.

Animals↗