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J T Lee

Publications and source records attributed to J T Lee.

At least 91 records · Page 5Linked to original sources
PubMed1999

Comparison of methods of point estimation in occupational epidemiologic studies.

Two common study designs of occupational epidemiologic studies are cohort mortality studies, which use the population at risk as a denominator, and proportionate mortality studies, which use the total number of events as a denominator. This study compared the various methods of point estimation for cohort mortality studies, i.e., RR (risk ratio), OR (odds ratio) and SMR (standardized mortality ratio), and those for proportionate mortality studies, i.e., PRR (proportionate risk ratio), POR (proportionate odds ratio) and PMR (proportionate mortality ratio). This study was based on a real dataset of all workers in Metropolitan Toronto, Canada, who applied for compensation for various types of injuries or diseases from the Workers' Compensation Board in 1980. Results showed that within the cohort mortality or proportionate mortality study designs, OR (or POR) in all cases gave the least conservative estimates (farthest away from the null value), while SMR (or PMR) gave the most conservative estimates. The empirical differences between the point estimators were generally small. Our results showed that between study designs the corresponding point estimators were poorly correlated. In addition, this empirical study indicated that the use of the mortality odds ratio did not improve the proportionate mortality study very much in terms of generating results similar to the risk ratio from the cohort mortality design. We drew two conclusions: first, the point estimators within each study design can generally be a good alternative to one another; and second, proportionate mortality studies are not a good approximation for cohort mortality studies.

Cohort Studies↗
PubMed1999

T2-weighted fast spin-echo MR findings of adenocarcinoma of the uterine cervix: comparison with squamous cell carcinoma.

The purpose of this study was to investigate the differences in MR findings of adenocarcinoma (AC) and squamous cell carcinoma (SCC) of the uterine cervix and to compare MR findings with pathologic findings. MR images of 17 patients with pathologically proven AC, using a fast spin-echo (FSE) T2-weighted image (T2WI) with pelvic phased-array coil on a 1.5-T unit, were retrospectively evaluated. After measurement of the signal intensity (SI) ratios of the region of interest between tumors and gluteus maximus muscle, we compared the ratios of AC with those of 16 patients with SCC. AC showed relatively high SI on FSE T2WI with multiseptated lesions in four cases and hydrometrocolpos in three cases. The mean SI ratio was 3.82 +/- 1.68 in AC and 2.35 +/- 0.42 in SCC (p < 0.0001, t-test). Multiple tumorous glands with cytoplasmic and intraglandular mucin or serous fluid were pathologically found in AC, but SCC revealed the compact cellularity of stratified squamous tumor cells. The cervical AC showed higher SI than SCC on FSE T2WI with occasional multiseptated lesions and hydrometrocolpos. If the SI ratio of the tumor was more than 3.0, AC could be diagnosed with a sensitivity of 68.8% and a specificity of 100%.

Adenocarcinoma↗
PubMed1999

Pericardial tamponade and massive pleural effusion complicating orthotopic heart transplantation.

Pericardial and pleural effusions occur commonly after open cardiac procedures. However, the combination of tamponade and massive pleural effusion is not often observed. We present a case of such a patient who received an orthotopic heart transplant in a setting of previously diagnosed systemic sarcoidosis. Treatment ultimately required the creation of a pericardial window and chemical pleurodesis.

Anti-Bacterial Agents↗
PubMed1999

Cancer pain management in home hospice settings: a comparison of primary care and oncologic physicians.

We compare the effectiveness of terminal cancer pain management delivered by primary care physicians with that of specialists in home-based hospice settings. Each visit record for 223 outpatients in three hospice programs was abstracted for physician type, patient age, medication usage, level of pain reported, cancer type, and metastatic status. Thirteen percent of patients reported no pain at any visit and 19% reported pain at all visits; half of the patients reported pain at two thirds of their visits. No difference was found in the presence or absence of pain between primary care and oncologic patients. When available, the level of pain reported (0-10 scale) was statistically (p < 0.01) but not clinically different between physician groups; average pain rating for primary care patients was 3.7 while the mean pain rating for oncologic patients was 3.1. The reported pain level varied significantly among facilities, as did physician mix. Multivariate analysis revealed that program and an interaction term between program and physician type, but not physician type independently, explained a significant amount of variation in pain level. Overall, reported pain remained higher than optimal. Research elsewhere has shown that application of the World Health Organization (WHO) cancer pain management guidelines can control 70%-90% of cancer pain. Strategies for implementing pain guidelines that emphasize a systems approach may be effective.

Aged↗
PubMed1998

Third-generation cephalosporins and vancomycin as risk factors for postoperative vancomycin-resistant enterococcus infection.

OBJECTIVE: To examine use of third-generation cephalosporins (3GCs) alone and in association with vancomycin hydrochloride as a risk factor for vancomycin-resistant enterococcus (VRE) infection in surgical patients. DESIGN: Case-control retrospective study analyzing antibiotic use in the 30 days preceding culture of VRE or vancomycin-sensitive enterococcus from an infected site. SETTING: A large tertiary care teaching hospital. PATIENTS: Surgical inpatients with VRE infections between September 3, 1993, and January 29, 1997, were matched with patients with vancomycin-sensitive enterococcus infections. Matches were based on surgical procedure, initial infection site, and immunosuppression. Matches were found for 32 of 50 surgical patients with VRE. Twenty matched pairs of patients were recipients of solid organ transplants. MAIN OUTCOME MEASURES: Multivariate logistic regression analysis was done to examine 3GCs and vancomycin as risk factors for VRE infection. Univariate analysis of use of other antibiotic agents and demographic data was also performed. RESULTS: Multivariate analysis showed significant differences in the use of 3GCs both alone and concurrently with vancomycin. Univariate analysis also showed higher use of metronidazole, concurrent vancomycin and metronidazole, concurrent vancomycin and ceftazidime, and all antibiotics combined in patients with VRE infections. CONCLUSIONS: This matched control study showed that use of 3GCs, alone (P=.05) or concurrently with vancomycin (P=.05), was a risk factor for VRE infection in surgical patients. Judicious administration of third-generation antibiotics is warranted in surgical patients with other risk factors for VRE.

Adult↗
PubMed1998

Purification of Sepharose-unbinding ricin from castor beans (Ricinus communis) by hydroxyapatite chromatography.

Sepharose-unbinding ricin was one-step separated and purified from a crude extract of castor beans (Ricinus communis) by affinity chromatography on hydroxyapatite. This purification method does not require the time-consuming and complicated steps, such as gel filtration and ion-exchange chromatography, that have been essential in the separation of Sepharose-unbinding toxins. Using this method, approximately 180 mg of ricin was obtained from 100 g of castor beans using a bed volume of 80 ml on a hydroxyapatite column. Weak affinity of the ricin on Sepharose was confirmed and compared with Sepharose-binding ricin (ricin D), using radioiodinated ricins. The molecular mass of the ricin was estimated to be 62 kDa by 10% SDS-PAGE under nonreducing conditions. Under reducing conditions, the purified ricin appeared to be two subunits, corresponding to the molecular masses of 30 and 32 kDa. The pI value was determined to be approximately 8.9 for the ricin. Uptake of the ricin by HeLa cells was measured as almost half of ricin D uptake. Similar results were observed on CEM cells as well. In vitro cytotoxicity of ricins on different cell lines was measured by the MTT method. When compared with ricin D, the purified ricin showed approximately 10-fold less cytotoxicity to HUT78 or K562 cells and 30-fold less toxicity to CEM cells. This lower cytotoxicity of the ricin may be due to its lower cell-binding properties as evidenced by its low affinity for the cell surfaces. From these results, the purified ricin was considered to be ricin E.

Ricinus communis↗
PubMed1998

Recommended practices for surveillance. Association for Professionals in Infection Control and Epidemiology, Inc. Surveillance Initiative working Group.

Demonstration of quality health care includes documentation of outcomes of care. Surveillance is a comprehensive method of measuring outcomes and related processes of care, analyzing the data, and providing information to members of the health care team to assist in improving those outcomes. Surveillance is an essential component of effective clinical programs designed to reduce the frequency of adverse events such as infection or injury. Although there is no single or "right" method of surveillance design or implementation, sound epidemiologic principles must form the foundation of effective systems and must be understood by key participants in the surveillance program and supported by senior management. Teamwork and collaboration across the health care spectrum are important for the development of surveillance plans. Each health care organization must tailor its surveillance systems to maximize resources by focusing on population characteristics, outcome priorities, and organizational objectives. To ensure quality of surveillance, the following elements must be incorporated: A written plan should serve as the foundation of any surveillance program. The plan should outline important objectives and elements of the surveillance process so that resources can be targeted appropriately. Thoroughness or intensity of surveillance for an area of interest must be maintained at the same level over time. Fluctuations of a surveillance rate have no meaning unless the same level of data collection is maintained. External rate comparisons are meaningless unless the systems used have comparable intensity. All the elements of surveillance should be used with consistency over time. This includes application of surveillance definitions and rate calculation methods. Personnel resources need to be appropriate for the type of surveillance being performed. This includes trained professionals who understand epidemiology and who have access to continuing professional education opportunities. Other resources essential to surveillance include computer support, information and technology services, clerical services, and administrative understanding and support to maintain a quality program. As a means of quality control and to ensure accuracy, the data and process of surveillance should undergo periodic evaluation and validation. This document is intended to assist professionals who plan and conduct surveillance programs as well as those who assure that there is appropriate organizational support to accomplish appropriate surveillance. While design of surveillance systems must be unique for each organization, incorporation of these seven core Recommended Practices for Surveillance provides a scientific framework to approach surveillance programs.

Cross Infection↗
PubMed1998

Development and validation of the Migraine-Specific Quality of Life Questionnaire.

This paper describes the development and validation of a migraine-specific quality-of-life instrument that is capable of measuring health-related quality-of-life impairments attributed to migraine. Item selection, item reduction, and pretesting and finalization of items during the instrument development phase resulted in a total of 16 questions which were incorporated into the Migraine-Specific Quality of Life Questionnaire (Version 1:0) (1992 Glaxo Wellcome Inc). Three meaningful dimensions were hypothesized: Role Function-Restrictive, Role Function-Preventive, and Emotional Function. In the instrument validation phase, the Migraine-Specific Quality of Life Questionnaire was mailed to 1109 migraine patients, providing a response rate of 45% (n = 458). Initial psychometric evaluation of the questionnaire indicated that it possessed adequate reliability with Cronbach's alpha for the three dimensions ranging between 0.70 to 0.85. The Migraine-Specific Quality of Life Questionnaire possessed adequate content and criterion validity. All but three items satisfied the test of construct validity. In conclusion, the Migraine-Specific Quality of Life Questionnaire has acceptable psychometric properties and can be used to estimate the effect of migraine and its treatment on the patient's health-related quality of life.

Adult↗
PubMed1998

Aversive gustatory stimulation activates limbic circuits in humans.

Animal studies implicate the amygdala and its connections in the recognition of aversive stimuli. A recent PET study demonstrated that the human amygdala and left orbitofrontal cortex show substantial increases in regional cerebral blood flow (rCBF) during exposure to aversive odourants. To examine if aversive gustatory stimuli similarly activate these regions, nine healthy women tasted an aversive saline solution, pure water and chocolate while rCBF was measured with PET. The aversive saline condition, when contrasted with the water condition, increased activity in the right amygdala, left anterior orbitofrontal cortex, medial thalamus, pregenual and dorsal anterior cingulate, and the right hippocampus. The right amygdala, left orbitofrontal cortex and pregenual cingulate remained significantly activated when saline was compared with chocolate. The present results indicate that the amygdala and orbitofrontal cortex respond to aversive stimuli in both the olfactory and gustatory modalities, and highlight the role of the pregenual cingulate in negative emotional processing.

Adult↗
PubMed1998

MR imaging during arterial portography for assessment of hepatocellular carcinoma: comparison with CT during arterial portography.

OBJECTIVE: The purpose of this study was to document the usefulness of MR imaging during arterial portography (MRAP) versus CT during arterial portography (CTAP) in the diagnosis and assessment of hepatocellular carcinoma. SUBJECTS AND METHODS: In addition to static T1- and T2-weighted MR imaging, MRAP was performed immediately after hepatic angiography through contrast material injection into intraarterially placed catheters (superior mesenteric or splenic artery) in 21 patients with nodular hepatocellular carcinoma. CTAP was performed afterward for each patient. The sensitivity and specificity of MRAP for lesion detection and the differential diagnosis of hepatocellular carcinoma were compared with the sensitivity and specificity of CTAP. RESULTS: MRAP revealed more perfusion defects (n = 56) than did CTAP (n = 46). The sensitivity for detection of hepatocellular carcinoma was higher for MRAP (94%) than for CTAP (83%); however, the difference was not statistically significant (p > .05). More hepatocellular nodules with unknown malignant potential were revealed on MRAP (n = 7) than on CTAP (n = 2). For the differential diagnosis of perfusion defects commonly revealed by both techniques, more benign lesions and pseudolesions (n = 14) were shown on MRAP through the combined interpretation with static images than on unenhanced and contrast-enhanced CTAP (n = 11). CONCLUSION: Because of its high sensitivity and its ability to enable radiologists to differentiate benign from malignant conditions, MRAP may have merit compared with CTAP in the assessment of hepatocellular carcinoma.

Adult↗
PubMed1998

Hepatic cavernous hemangioma: sonographic patterns and speed of contrast enhancement on multiphase dynamic MR imaging.

OBJECTIVE: Our purpose was to investigate a correlation between the speed of contrast enhancement in patients with hepatic cavernous hemangioma revealed by dynamic MR imaging and the internal echo pattern revealed by sonography. MATERIALS AND METHODS: Forty-five patients underwent multiphase IV contrast-enhanced dynamic MR imaging that revealed 71 hepatic cavernous hemangiomas less than 4 cm in diameter; the MR findings were compared with the sonographic findings in these patients. On MR imaging, the hemangiomas were classified as rapid-, intermediate-, and slow-enhancing. We classified sonographic features as hypoechoic, iso- or mixed-echoic, and hyperechoic according to the relative echogenicity seen between lesions and the surrounding hepatic parenchyma. Sonographic patterns and MR imaging findings of individual lesions were then compared. RESULTS: Rapid-enhancing hemangiomas revealed on dynamic MR imaging tended to be hypoechoic on sonography (18/24, 75%; p = .0143), and lesions that were slow-enhancing on MR imaging tended to be hyperechoic (26/29, 90%; p < .0001). Hypoechoic lesions on sonography tended to be rapid-enhancing on dynamic MR imaging (18/18, 100%). Likewise, hyperechoic lesions on sonography tended to be slow-enhancing on MR imaging (26/33, 79%; p = .0009). CONCLUSION: In most patients with hepatic cavernous hemangiomas, we found that the speed of contrast enhancement on multiphase dynamic MR imaging enabled us to predict the echo pattern in sonography and vice versa.

Contrast Media↗
PubMed1998

Bone marrow immunoscintigraphy (BMIS): a new and important tool for the assessment of marrow fibrosis in renal osteodystrophy?

One of the classic histologic forms of renal osteodystrophy is osteitis fibrosa, and its distinguishing characteristic is bone marrow (BM) fibrosis, caused by the activation of marrow parenchymal cells. A bone biopsy must be performed in order to establish the diagnosis of renal osteodystrophy. The clinical use of bone biopsy is restricted, however, due to the invasiveness of the procedure. In recent studies, bone scans have provided information useful for the differential diagnosis between osteomalacia and osteitis fibrosa. However, bone scans can not provide information on the bone marrow status. Bone marrow immunoscintigraphy (BMIS) using Tc-99m anti-granulocyte antibody (AGA), a highly sensitive test for the detection of bone marrow abnormalities which is also a noninvasive method, has rarely been reported in chronic renal failure (CRF). BMIS can provide information in patients with myelofibrosis. The purpose of this study was to evaluate the usefulness of BMIS in CRF patients with special regards to biochemical parameters. Nineteen CRF patients (13 men, 6 women; mean age: 48 +/- 11 years) in whom bone scintigraphy using Tc-99m MDP (methylene diphosphonate) showed the so-called superscan pattern were included in the study. Their primary renal diseases were chronic glomerulonephritis (n = 14), diabetes (n = 4), and polycystic kidney disease (n = 1). Modes of therapies were continuous ambulatory peritoneal dialysis (CAPD) (n = 13; mean duration: 9.5 months), HD (n = 5; mean duration: 7.8 months), and conservative treatment (n = 1). BMIS using Tc-99m labeled anti-granulocyte monoclonal mouse antibody BW250/183 was performed, and the results were compared with the biochemical parameters of the patients. According to the presence of BM expansion, which may represent marrow fibrosis, the 19 patients were divided into two groups: Group I (n = 7) with BM expansion and Group II (n = 12) with normal marrow distribution. The biochemical parameters and bone markers of Group I were compared with those of Group II. There was no significant difference in biochemical parameters (blood hemoglobin, serum ferritin, erythropoietin, BUN, creatinine) between the two groups. There were no significants difference in serum calcium, phosphorus, tartate-resistant acid phosphatase (TRAP), and intact parathyroid hormone (iPTH) between the two groups. Serum alkaline phosphatase (ALP) and osteocalcin were significantly (P < 0.05) higher in Group I than in Group II. These results suggest that patients with bone marrow expansion in BMIS have increased levels of ALP and osteocalcin, indicating an increased osteoblastic activity. BMIS may be useful for the detection of bone marrow expansion due to marrow fibrosis in renal osteodystrophy, and for the evaluation of the extent of bone marrow fibrosis.

Biomarkers↗
PubMed1998

Contemporary wound infection surveillance issues.

Contemporary wound infection surveillance is inexact. Tracking down suspicious incisions with maximal accuracy to isolate the subset of healing failures attributable to established tissue invasion by infecting pathogens has a solitary purpose: to learn how to improve one aspect of surgical practice. Wound infection is always the result of complex, probabilistic interplay of numerous concealed variables. A wound infection rate, whether determined for a hospital, a specialty, a risk class, an operation type, or a surgeon, only approximates a degree of failure to achieve one kind of surgical perfection. Interpretation of any rate will be flawed if issues of accuracy and meaning are suppressed. Gathering and revealing circumstances of individual infections may heuristically affect surgical teams. Interpretation of surveillance wound infection rates, infection rate comparisons to standards as a means of performance measurement, and particularly the meaning of rate changes over time in a hospital are matters of more than academic importance. Given current health care reform and a widespread fascination with industrial process-improvement philosophy, wound infection surveillance programs may be natural test platforms for probing surgical relevance of several quality-improvement methodologies. It is not a trivial fact that wound infection shares important prototypical features with most contemporary surgical care process flaws: rare, random, multifactorial in cause, costly, and impossible to uniformly preclude or predict.

Humans↗
PubMed1997

PET study of the localization and laterality of lingual somatosensory processing in humans.

Regional cerebral blood flow (rCBF) was measured using positron emission tomography (PET) during four tasks in right-handed volunteers with eyes closed: resting, protruding the tongue, stroking the left side of the protruding tongue, and stroking the right side of the protruding tongue. The primary somatosensory tongue representation (S1) mapped to the contralateral central sulcus (Brodmann (BA) 3/4) at approximately 28 mm above the intercommissural plane. Of note, stimulation of the left side of the tongue produced also an ipsilateral S1 response. Analysis of variance (ANOVA) of rCBF at S1 across all four conditions yielded only a significant effect for tongue stimulation, with no effect of laterality; the usually large asymmetries (contralateral >> ipsilateral) in S1 did not surface. We hypothesize that this atypical activation pattern arises from the tongue's specialization for language.

Adolescent↗
PubMed1997

Reversed-phase high-performance liquid chromatography of radioiodinated salmon calcitonins.

Reversed-phase HPLC conditions for simultaneous separation of salmon calcitonin, mono- and di-radioiodinated salmon calcitonins and their tryptic digested fragments have been developed. Salmon calcitonin was radioiodinated with Na125I by the iodo-beads method. After solid-phase extraction from the reaction mixtures using C18 Bond Elut cartridges, mono- and di-radioiodinated salmon calcitonins were separated from each other, as well as from unlabeled salmon calcitonin, on a Bondclone 10 C18 column (300x7.8 mm I.D.) by isocratic elution with 0.1% trifluoroacetic acid in 34% aqueous acetonitrile. The characteristics of either iodinated peptides or unlabeled salmon calcitonin were evaluated on the basis of UV absorbance (215 and 280 nm), fluorescence (lambda(ex)=282 nm, lambda(em)=310 nm) and measurement of specific radioactivity by means of a flow-through radio-isotope detector. HPLC separation of a tryptic digest of iodinated salmon calcitonin fraction on a W-porex 5 C18 300 A column (250x4.6 mm I.D.) and subsequent amino acid analysis, led to the conclusion that radioiodination took place at the Tyr residue and not at the His moiety.

Amino Acid Sequence↗
PubMed1997

Long-range cis effects of ectopic X-inactivation centres on a mouse autosome.

In mammals, the X chromosome is unique in being capable of complete inactivation. Such X inactivation evolved to compensate for gene dosage differences between females with two X chromosomes and males with one. Transcriptional silencing of a single female X chromosome is controlled in cis by Xist, whose RNA product coats the inactive X chromosome (Xi), and the X-inactivation centre (Xic). A transgenic study limited the Xic to 450 kilobases including Xist, and demonstrated that it is sufficient to initiate X inactivation. Here we report that ectopic Xist RNA completely coats transgenic chromosome 12. Expression of genes over 50 centimorgans was reduced two-fold and was detected only from the normal homologue in fibroblasts. Moreover, ectopic Xic action resulted in chromosome-wide changes that are characteristic of the X(i): DNA replication was delayed, and histone H4 was markedly hypoacetylated. Our findings suggest long-range cis effects on the autosome similar to those of X inactivation, and imply that the Xic can both initiate X inactivation and drive heterochromatin formation. Thus, the potential for chromosome-wide gene regulation is not intrinsic to X-chromosome DNA, but can also occur on autosomes possessing the Xic.

Acetylation↗