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Biomedical subjects

T A Lee

Publications and source records attributed to T A Lee.

18 recordsLinked to original sources
PubMed2005

Pathogenic relevance of Lactobacillus: a retrospective review of over 200 cases.

Given that Lactobacillus has been reported to be the causative pathogen in many types of infection despite debate regarding the organism's clinical significance, a literature review was conducted to investigate the treatments and outcomes of Lactobacillus infections reported to date. In this article, the characteristics of over 200 reported cases of Lactobacillus-associated infections are summarized. Lactobacillus was found to be frequently associated with endocarditis and bacteremia. Lactobacillus was also associated with a variety of other infections including, but not limited to, peritonitis, abscesses, and meningitis. The species casei and rhamnosus were the most common. The isolates tended to be most sensitive to erythromycin and clindamycin and most resistant to vancomycin. The species that was most sensitive to vancomycin was acidophilus. The overall mortality rate was nearly 30%. There was a significant association between mortality and polymicrobial infection (P=0.004). In the subset of patients with bacteremia, increased mortality was associated with inadequate treatment (P=0.001) and polymicrobial bacteremia (P=0.044).

Adolescent↗
PubMed2003

An automated overlying water-renewal system for sediment toxicity studies.

An automated water-renewal toxicity test system is described for exposing benthic invertebrates to whole sediments. The system will intermittently deliver laboratory or on-site water for overlying water replacement in sediment exposures. A range of cycle rates can be used to produce different volume additions of overlying water per day to exposure chambers. The system can be used with six different treatments and eight replicates per treatment producing 48 exposure chambers. Three formulated sediments with variable organic carbon (1.5%, 7.5%) and sand (14%, 63%) content were prepared to test the system exposing amphipods, Hyalella azteca and midges, Chironomus tentans in 10 day whole sediment tests. Intermittent water flow was used with a 90 min cycle time to create two volume additions of laboratory water per 24 h in exposure chambers (180 ml sediment, 320 ml water). Overlying water quality conditions, and survival and growth of both species were consistent and within acceptable limits for the testing requirements of the U.S. EPA guidelines for sediments with freshwater invertebrates.

Animals↗
PubMed2001

Economic evaluation of systemic treatments for cytomegalovirus retinitis in patients with AIDS.

OBJECTIVE: To determine the cost of using systemic therapy to treat newly diagnosed cytomegalovirus (CMV) retinitis in persons with AIDS. DESIGN: Incidence-based simulation model of CMV treatment from a government payer perspective. SETTING: Swiss healthcare system. PATIENTS AND PARTICIPANTS: Patients with AIDS and newly diagnosed CMV retinitis. INTERVENTIONS: Patients were assigned to 1 of 4 treatment regimens for induction and maintenance therapy: (i) intravenous (IV) cidofovir induction and maintenance (cidofovir IV/IV); (ii) IV foscarnet induction and maintenance (foscarnet IV/IV); (iii) IV ganciclovir induction and maintenance (ganciclovir IV/IV); and (iv) IV ganciclovir induction and oral (PO) ganciclovir maintenance (ganciclovir IV/PO). Following a second relapse, patients were assigned to one of the other regimens. MAIN OUTCOME MEASURES: Time to first and subsequent progression, duration of maintenance treatment and direct medical expenditures [1998 Swiss francs (SwF)] . RESULTS: The median time to first progression was longest for cidofovir IV/IV, followed by foscarnet IV/IV, ganciclovir IV/IV and ganciclovir IV/PO. Mean survival was 13 months and mean costs for this period in the base case were lowest in those initially treated with cidofovir (SwF146,742), followed by initial treatment with foscarnet IV/IV (SwF194,809), ganciclovir IV/PO (SwF195,190) and ganciclovir IV/IV (SwF243,964). Costs were most sensitive to changes in efficacy estimates. CONCLUSIONS: Of the regimens studied, initiation of treatment with systemic cidofovir appears least costly over a 13-month period.

AIDS-Related Opportunistic Infections↗
PubMed2000

Exogenous E2F expression is growth inhibitory before, during, and after cellular transformation.

To gain insight into the tumor suppressor properties of E2F1, we investigated growth inhibition by the E2F family of transcription factors using a tissue culture model system. We first show that exogenous E2F expression causes an 80% decrease in NIH3T3 colony formation and activated c-Ha-Ras-mediated focus formation. Inhibition of Ras-mediated transformation was dependent upon E2F DNA binding activity but did not require amino- or carboxy-terminal E2F1 protein interaction domains. Because E2F upregulation has been suggested to be associated with a neoplastic phenotype, it was possible that increased E2F activity would not be inhibitory to previously transformed cells. However, we found that exogenous E2F was also inhibitory to growth of NIH3T3 cells previously transformed by Ras or Neu. Further characterization revealed that exogenous E2F expression is inhibitory at very early times after transfection, causing dramatic losses in transfected cell populations. Interestingly, those few cells which do establish appear to be unaffected by the overexpressed E2F. Therefore, we propose that increased E2F activity may only be tolerated in a subset of cells which have acquired specific alterations that are dominant over E2F-mediated growth inhibition.

3T3 Cells↗
PubMed2000

The economic burden of COPD.

COPD is one of the leading causes of morbidity and mortality worldwide and imparts a substantial economic burden on individuals and society. Despite the intense interest in COPD among clinicians and researchers, there is a paucity of data on health-care utilization, costs, and social burden in this population. The total economic costs of COPD morbidity and mortality in the United States were estimated at $23.9 billion in 1993. Direct treatments for COPD-related illness accounted for $14.7 billion, and the remaining $9.2 billion were indirect morbidity and premature mortality estimated as lost future earnings. Similar data from another US study suggest that 10% of persons with COPD account for > 70% of all medical care costs. International studies of trends in COPD-related hospitalization indicate that although the average length of stay has decreased since 1972, admissions per 1,000 persons per year for COPD have increased in all age groups > 45 years of age. These trends reflect population aging, smoking patterns, institutional factors, and treatment practices.

Adult↗
PubMed1999

Determination of kinetic isotope effects for nucleoside hydrolases using gas chromatography/mass spectrometry.

Kinetic isotope effects are widely used to determine the transition state of chemical and enzymatic reactions. Radioactive isotopes are used most often to determine these kinetic isotope effects. However, stable isotopes offer a number of advantages over the use of radioactive isotopes. These advantages include ease of handling and disposal along with increased safety in the laboratory. [1'-(13)C]Inosine and [1'-(2)H]inosine kinetic isotope effects were determined using a gas chromatograph in conjunction with a mass selective detector for nucleoside hydrolase, a purine-metabolizing enzyme. Three ion pairs were used to determine kinetic isotope effects. These ion pairs were 158/159, 187/188, and 217/218. The average isotope effects for all ion pairs were 1.021 +/- 0.006 for [1'-(13)C]inosine and 1.113 +/- 0.008 for [1'-(2)H]inosine. The transition state consistent with these isotope effects is also consistent with the transition state proposed by Schramm and Horenstein using radioactive substrates.

Animals↗
PubMed1991

A multiple mass spectral line method for determining positional specific activities in stable isotope-labeled amino acids.

A method for determining the position and enrichment of isotope labels in amino acids using gas chromatography/mass spectrometry is described. [alpha-15N]- and [epsilon-15N]lysine, [1-13C]- and [15N]alanine and -leucine, and [1-13C]-, [2-13C]-, [3-13C]-, and [4-13C]aspartic acid were investigated. Standards for each isotope label were prepared and analyzed under scan conditions, and line pairs characteristic for the label were identified. The standards were reanalyzed under selective ion monitoring conditions to verify the behavior of the line pairs. Mixtures of amino acids containing different isotope labels or the same label in different positions were prepared and analyzed under selective ion monitoring conditions. Enrichments were determined with high precision and relative errors ranging from 0.14 to 36%.

Amino Acids↗
PubMed1990

The use of multiple mass spectral line pairs for enhanced precision in isotope enrichment studies of 15N-labeled amino acids.

A method for enhancing the precision in the calculation of isotope enrichment for 15N-labeled amino acids is presented. The method utilizes multiple line pairs for the calculation of isotope enrichment. Using multiple line pairs allows the evaluation of calibration curves for nonlinear behavior and permits differentiation among sites containing more than one labeled nitrogen. The increase in precision is related to the number of isotopically shifted line pairs used in calculating the isotopic enrichment and varies with the amino acid of interest.

Amino Acids↗
PubMed1988

Cranial MR imaging in neurofibromatosis.

Cranial MR images of 53 patients with neurofibromatosis were reviewed to determine the nature, extent, and number of intracranial abnormalities present. All patients studied met tentative definitions established for the diagnosis of neurofibromatosis. Twenty-three were scanned for evaluation of known CNS of cranial nerve involvement; the remainder were neurologically asymptomatic patients without suspected lesions referred for screening. Single lesions were noted in 32 patients. Multiple lesions were identified in 14 patients. Seven had normal scans. In 23 patients small focal areas of increased signal on T2-weighted scans within the brain were though to represent heterotopias. Eight patients had chiasmal gliomas and two had optic nerve gliomas. Nine patients had parenchymal gliomas, two had ischemic changes, and one had a colloid cyst. Extraaxial lesions included acoustic neuromas (five patients), meningiomas (four), trigeminal neurofibromas (one), and dysplasia of a sphenoid wing (two). Of the 30 asymptomatic patients referred for screening, lesions were found in 23. MR was found to be an excellent method of imaging known disease and of detecting lesions in asymptomatic patients. Because of the large number of asymptomatic lesions detected in this population, a screening MR study is recommended in patients with neurofibromatosis.

Adolescent↗
PubMed1984

Cyheptamide and 3-hydroxy-3-phenacyloxindole: structural similarity to diphenylhydantoin as the basis for anticonvulsant activity.

The molecular structures of cyheptamide and 3-hydroxy-3- phenacyloxindole were determined by X-ray diffraction methods. The amide group in both compounds exhibits delocalization of the pi-electrons over the three atoms (N, C, and O), while the bond linking the amide to the tetrahedral carbon atom is a single bond. These structural features are also present in two drugs used for the treatment of generalized tonic-clonic ( GTC ) seizures, namely, carbamazepine and diphenylhydantoin. The shapes of cyheptamide , 3-hydroxy-3- phenacyloxindole , and carbamazepine have three features that are the same and can be simultaneously overlapped, the amide and two hydrophobic regions, whereas diphenylhydantoin fits two of the three regions at one time. These structural and electronic features are analyzed in light of current models for anticonvulsant activity.

Animals↗
PubMed1972

Flowering and Growth Response of Peanut Plants (Arachis hypogaea L. var. Starr) at Two Levels of Relative Humidity.

Peanut plants (Arachis hypogaea L. var. Starr) grown under two different relative humidities were used in all experiments. All plants were germinated and grown to flowering in the greenhouse. At this time, one group was moved to a growth room under 95% relative humidity. After 50 days the humidity of the growth room was lowered to 50%. The second group was moved into a growth room at 50% relative humidity and after 50 days the humidity was raised to 95%.Flowering rates of plants under high humidity were greater than rates of those plants under low humidity. Flowering was stimulated by transfer from low to high humidity, and these plants set the largest percentage of pegs, maintained a high rate of ethylene production by 2-centimeter peg sections, a high growth rate of intact pegs, and they had a higher mean content of gibberellins than plants transferred from a high to a low humidity. The plants in the high to low transfer had the least number of flowers, formed the lowest percentage of pegs, had about 50% less ethylene production by 2-centimeter peg sections, and the peg growth rate declined about 50%.Maximum ethylene production occurred during initial stages of peg growth (1- to 5-millimeter sections), and gibberellin content was generally higher in these peg sections. Thus, high humidity enhanced flowering, peg formation, and peg growth rate. A causal relationship between these effects of high humidity and the growth regulator status of the developing fruit is indicated.

Journal Article↗
PubMedDate not supplied

Evaluating the use and quality of pharmacy drive-up services.

OBJECTIVE: To evaluate the use and quality of pharmacy drive-up services; specifically, to assess patients' and pharmacists' views of the drive-up and determine the implications for assuring or improving the quality of the services provided. DESIGN: Questionnaires developed for patients and pharmacists addressed aspects of pharmacy drive-up services. The patient questionnaire asked about prescription information and drive-up use, satisfaction with pharmacy services, importance of patronage factors, comfort in using the drive-up, and comparison of drive-up and in-store visits. The pharmacist questionnaire was similar in content, but also contained open-ended questions pertaining to the provision of pharmaceutical care at the drive-up pharmacy. SETTING: Six pharmacies in Central Iowa. PARTICIPANTS: A sample of patients who had received at least one prescription from a participating pharmacy in the previous 30 days; pharmacists from participating pharmacies. MAIN OUTCOME MEASURES: Responses from users and nonusers of the pharmacy drive-up. RESULTS: Both users and nonusers of the drive-up indicated that pharmacist-linked services--those that entail direct pharmacist-patient contact and are closely associated with the ideals of pharmaceutical care--may be provided better in-store. The pharmacists also indicated that these services were provided better in-store and mentioned other ways in which drive-up services may detract from patient care. CONCLUSION: As pharmacist-linked services become more important in health care, and as drive-up pharmacy services increase in popularity, the compatibility of drive-up service with a greater emphasis by pharmacists on patient care will increasingly become an issue. To allay potential concerns and improve the quality of service, pharmacists need to take additional steps to assess drive-up patients' level of familiarity with their medications, require patients to come into the pharmacy periodically, and, where necessary, provide alternative services at the drive-up.

Adult↗
PubMedDate not supplied

Performance of community pharmacy drug interaction software.

OBJECTIVE: To evaluate the performance of computerized drug-drug interaction (DDI) software in identifying clinically important drug-drug interactions. DESIGN: One-time performance test of computer systems using a standard set of prescriptions. SETTING: Community pharmacies or central corporate locations with pharmacy terminals identical to those used in actual pharmacies. PARTICIPANTS: Chain and health maintenance organization (HMO) pharmacies with seven or more practice sites in Washington State. A total of nine different DDI software programs were installed in 516 community pharmacies represented by these chains and HMOs. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive values of software in detecting 16 well-established DDIs contained within six fictitious patient profiles. RESULTS: The software systems failed to detect clinically relevant DDIs one-third of the time. Sensitivity of the software programs ranged from 0.44 to 0.88, with 1.00 being perfect; specificity ranged from 0.71 to 1.00; positive predictive value ranged from 0.67 to 1.00; and negative predictive value ranged from 0.69 to 0.90. For software packages that were installed at different locations, between-installation differences were observed. CONCLUSION: The performance of most DDI-detecting software programs tested in this study was suboptimal. Improvement is needed to advance their contribution to detection of DDIs.

Drug Interactions↗