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Biomedical subjects

C Lee

Publications and source records attributed to C Lee.

At least 181 records · Page 10Linked to original sources
PubMed2001

Srg3, a mouse homolog of yeast SWI3, is essential for early embryogenesis and involved in brain development.

Srg3 (SWI3-related gene product) is a mouse homolog of yeast SWI3, Drosophila melanogaster MOIRA (also named MOR/BAP155), and human BAF155 and is known as a core subunit of SWI/SNF complex. This complex is involved in the chromatin remodeling required for the regulation of transcriptional processes associated with development, cellular differentiation, and proliferation. We generated mice with a null mutation in the Srg3 locus to examine its function in vivo. Homozygous mutants develop in the early implantation stage but undergo rapid degeneration thereafter. An in vitro outgrowth study revealed that mutant blastocysts hatch, adhere, and form a layer of trophoblast giant cells, but the inner cell mass degenerates after prolonged culture. Interestingly, about 20% of heterozygous mutant embryos display defects in brain development with abnormal organization of the brain, a condition known as exencephaly. Histological examination suggests that exencephaly is caused by the failure in neural fold elevation, resulting in severe brain malformation. Our findings demonstrate that Srg3 is essential for early embryogenesis and plays an important role in the brain development of mice.

Animals↗
PubMed2001

Modulation of Chelidonii herba on GABA activated chloride current in rat PAG neurons.

Modulation of Chelidonii herba on gamma-aminobutyric acid (GABA) activated chloride current in the acutely dissociated periaqueductal gray (PAG) neuron was studied by nystatin-perforated patch-clamp technique. High concentrations of Chelidonii herba elicited ion current, that was blocked by bicuculline. Low concentrations reduced the GABA activated current in PAG. Two types of inhibitory action of Chelidonii herba on GABA activated current have been implicated in PAG. One is the inhibitory action of Chelidonii herba on GABA was abolished by naltrexone and the other is that of Chelidonii herba was potentiated by naltrexone. In addition, all of two types of action of Chelidonii herba are linked to pertussis toxin-sensitive GTP-binding proteins. These results suggest that the inhibitory modulation of Chelidonii herba on GABA activated current via G-proteins in PAG neuron is an important analgesic mechanism.

Animals↗
PubMed2001

Stereotactic core-needle breast biopsy: a multi-institutional prospective trial.

PURPOSE: To assess the accuracy of stereotactic core-needle biopsy (CNB) of nonpalpable breast lesions within the context of clinically important parameters of anticipated tissue-sampling error and concordance with mammographic findings. MATERIALS AND METHODS: CNB was performed in 1,003 patients, with results validated at surgery or clinical and mammographic follow-up. Mammographic findings were scored according to the American College of Radiology Breast Imaging Reporting and Data System with a similar correlative scale for histopathologic samples obtained at either CNB or surgery. Agreement of CNB findings with surgical findings or evidence of no change during clinical and mammographic follow-up (median, 24 months) for benign lesions was used to determine results. Three forms of diagnostic discrimination measures (strict, working [strict conditioned by tissue sampling error], applied [working conditioned by concordance of imaging and CNB findings) were used to evaluate the correlation of CNB, surgical, and follow-up results. RESULTS: Strict, working, and applied sensitivities were 91% +/- 1.9; 92% +/- 1.8, and 98% +/- 0.9, respectively; strict, working, and applied specificities were 100%, 98% +/- 0.8, and 73% +/- 0.9; strict, working, and applied accuracies were 97%, 96%, and 79%. CONCLUSION: Percutaneous stereotactic CNB is an accurate method to establish a histopathologic diagnosis of nonpalpable breast lesions. Accuracy increases when additional surgery is performed for lesions with anticipated sampling error or when CNB findings are discordant with mammographic findings. An understanding of the interrelationship among these parameters is necessary to properly assess results.

Biopsy, Needle↗
PubMed2001

Regional cerebral blood flow changes in patients with intractable obsessive compulsive disorders treated by limbic leukotomy.

The object of this study is to assess the changes in regional cerebral blood flow (rCBF) following stereotactic limbic leukotomy in patients with medically intractable Obsessive-Compulsive Disorder (OCD). Technetium-99-Hexa Methyl Propylene Amine Oxime (99mTc-HMPAO) Single Photon Emission Computed Tomography (SPECT) data obtained before and after limbic leukotomy were subjected to image fusion with MRI images. Eight samples were obtained from healthy voluteers. After localization of the ROI (Region Of Interest) in anatomical area, rCBF measurements were obtained by METLAB. The results of this study show a change of rCBF following limbic leukotomy in intractable OCD. Postoperative 99mTc-HMPAO SPECT findings implicate the medial frontal cortex, cingulate and striatum, which culd be linked to limbic leukotomy that blocks the functional connection of corticolimbic loop.

Adult↗
PubMed2001

"Operation Sick Bay": an opportunity for community service learning.

"Operation Sick Bay" was the inspiration of the 3 full-time nurses at Framingham High School, which has a population of 1,800 students and 300 teachers and staff. The primary focus of Operation Sick Bay was to create a health services environment conductive to learning about health and illness, developing lifetime skills in self-help and self-care, providing a restful atmosphere, and involving students and staff in taking pride in their school health services center. The "sick bays" are small units with privacy curtain closures used for students who need to lie down because of illness. There are 3 bays for female students and 3 for male students. Instead of the usual cream-colored walls, the project provided the opportunity to create a colorful environment designed to provide health information to students.

Financial Support↗
PubMed2001

Detection of inducible nitric oxide synthase- and nitrotyrosine-positive cells in the lesions of pericarditis induced by porcine enterovirus serotype 3 infection.

The expression of inducible nitric oxide synthase (iNOS), an enzyme that produces nitric oxide, was examined in the hearts of pigs infected with porcine enterovirus serotype 3 (PEV3). Piglets orally infected with PEV3 developed tremors and paralysis 3-7 days post-infection. Affected animals had pericarditis and myocarditis. There were fibrin and inflammatory cell infiltrates (macrophages and neutrophils) in the pericardial sac and myocardium. Immunohistochemically, the majority of inflammatory cells in the pericardial sac were positive for iNOS and nitrotyrosine, an end product of nitric oxide. These results suggest that iNOS is upregulated in the pericardial lesion, and that increased nitric oxide production plays an important role in the development of PEV3-induced pericarditis and myocarditis.

Animals↗
PubMed2001

Overtightening of the ankle syndesmosis: is it really possible?

BACKGROUND: Many surgeons and orthopaedic references recommend that fixation of a disrupted distal tibiofibular syndesmosis be performed with the ankle in dorsiflexion to avoid overtightening and subsequent restriction of ankle dorsiflexion. This recommendation is based in large part on one cadaveric study without clinical correlation. The purpose of the present study was to examine whether overtightening of the syndesmosis limits maximal ankle dorsiflexion. METHODS: Nineteen cadaveric ankles were used for the study. Each ankle was tested for the initial range of motion after release of the Achilles tendon proximal to the ankle joint. All capsular and ligamentous structures remained intact. Kirschner wires were placed in the tibia and talus. The angle between the wires with the ankle maximally dorsiflexed was measured before and after syndesmotic compression. Syndesmotic compression was achieved with a 4.5-mm lag screw with the ankle in plantar flexion. RESULTS: There was no difference between the values for maximal dorsiflexion before and after syndesmotic compression. CONCLUSIONS: Syndesmotic compression in and of itself does not diminish ankle dorsiflexion in a cadaveric model. CLINICAL RELEVANCE: Maximal dorsiflexion of the ankle during syndesmotic fixation is not required in order to avoid loss of dorsiflexion. It is likely that the most important aspect of syndesmotic fixation is anatomic reduction of the syndesmosis and that the degree of ankle dorsiflexion during fixation is not important.

Ankle↗
PubMed2001

Minimally invasive approaches to mandibular fractures.

Excellence in mandibular fracture repair requires anatomic restoration of the displaced bone segments, maintenance of the reduction until bone union has been confirmed, and minimization of surgical stigmata. Repairs should ideally be cost-effective, reproducible, adaptable, and expeditiously executed. Fractures of two subregions of the mandible, the condylar neck and the symphysis, can benefit from minimally invasive surgical techniques. The use of these techniques in the mandible is reviewed.

Endoscopy↗
PubMed2001

Automated nasopharyngeal carcinoma detection with dynamic gadolinium-enhanced MR imaging.

OBJECTIVES: The purpose of this research is to develop an automatic medical diagnosis for segmenting nasopharyngeal carcinoma (NPC) with dynamic gadolinium-enhanced MR imaging. METHODS: This system is a multistage process, involving motion correction, head mask generation, dynamic MR data quantitative evaluation, rough segmentation, and rough segmentation refinement. Two approaches, a relative signal increase method and a slope method, are proposed for the quantitative evaluation of dynamic MR data. RESULTS: The NPC detection results obtained using the proposed methods had a rating of 85% in match percent compared with these lesions identified by an experienced radiologist. The match percent for the two proposed methods did not have significant differences. However, the computation cost for the slope method was about twelve times faster than the relative signal increase method. CONCLUSIONS: The proposed methods can identify the NPC regions quickly and effectively. This system can enhance the performance of clinical diagnosis.

Analysis of Variance↗
PubMed2001

Protein glycation: creation of catalytic sites for free radical generation.

In a glycation reaction, alpha-dicarbonyl compounds such as deoxyglucosone, methylglyoxal, and glyoxal are more reactive than the parent sugars with respect to their ability to react with amino groups of proteins to form inter- and intramolecular cross-links of proteins, stable end products called advanced Maillard products or advanced end products (AGEs). The AGEs, which are irreversibly formed, accumulate with aging, atherosclerosis, and diabetes mellitus, and are especially associated with long-lived proteins such as collagens, lens crystallins, and nerve proteins. It was suggested that the formation of AGEs not only modifies protein properites but also induces biological damage in vivo. In this report, we summerize results obtained from our studies for (1) identifying the structure of the cross-linked radical species formed in the model system-the reaction between alpha-dicarbonyl methylglyoxal with amino acids, and (2) the reactivity of the radical center of the protein created by the similar reaction. These results indicate that glycation of protein generates active centers for catalyzing one-electron oxidation-reduction reactions. This active center, which exhibits enzyme-like character, is suggested to be the cross-linked Schiff-based radical cation of the protein. It mimics the characteristics of the metal-catalyzed oxidation system. These results together indicate that glycated proteins accumulated in vivo provide stable active sites for catalyzing the formation of free redicals.

Aging↗
PubMed2001

Physician Order Entry impact on drug turn-around times.

This paper describes a study of the impact of Physician Order Entry (POE) on pharmacy order turn-around times. The study looked at two surgical services, Neurosurgery and Transplant, of a large Midwestern academic medical center. Pharmacy orders were followed in these units from the time a physician wrote an order to the time the patient received the medication. The first part of the study tracked pharmacy orders for a two-month period before the implementation of POE and the second part of the study tracked pharmacy orders for a two-month period after POE had been implemented. The pre- and post-POE pharmacy turn-around times were compared. It was expected that the data would show a substantial decrease in pharmacy order turn-around times. Our study did, in fact, show a significant reduction in this turn-around-time.

Clinical Pharmacy Information Systems↗
PubMed2001

The disability profile of patients with schizophrenia in psychiatric hospital and community settings in Singapore.

The disability profile of persons with schizophrenia in Singapore and how disability levels vary in patients cared for in the community and in the long-stay wards of a state mental hospital were studied using the Life Skills Profile (LSP). The inter-rater reliability of the LSP assessed by the intraclass correlation coefficient (ICC), was lower than in the Australian studies. The test-retest ICCs for the total LSP score and the five subscale scores were satisfactory for the hospitalised subjects and for the community psychiatric nurse subjects, but generally poor for the community care facility subjects. The average ICCs were lower compared to the Australian study. Female hospitalised subjects but not male hospitalised subjects returned higher disability scores on all LSP scales compared to community subjects. This study provided some preliminary data on the usefulness and validity of the LSP in a multi-ethnic Asian setting like Singapore. If the LSP is used as a measure of disability in schizophrenia, it would appear that ratings should only be made by those who know the subject well, and that raters should be formally trained mental health professionals.

Community Mental Health Centers↗
PubMed2000

The human cytochrome P450 1A1 mRNA is rapidly degraded in HepG2 cells.

The cytochromes P450 are a superfamily of enzymes that can carry out a wide range of oxidative reactions. While the transcriptional control of the cytochrome P450 genes has been relatively well-studied, posttranscriptional regulatory mechanisms that contribute to the regulation of P450s are much less well understood. We followed the decay of CYP1A1, CYP1A2, and CYP1B1 mRNAs after induction by the AH receptor ligand 2,3,7,8,-tetrachlorodibenzo-p-dioxin. CYP1A2 and CYP1B1 mRNAs were long-lived in this cell line (to > 24 h). In contrast, the CYP1A1 mRNA decays remarkably quickly. To determine if this rapid decay was unique to CYP1A1, we assessed the decay of selected human P450 and liver-specific mRNAs in HepG2 cells as a comparison. We analyzed albumin, phosphofructokinase, and GAPDH mRNAs and found that they were long-lived, with half-lives >24 h. We show that CYP2E1 mRNA can be detected in HepG2 cells by RT-PCR and that this mRNA also has a basal half-life of >24 h. Thus the CYP1A1 mRNA with its half-life of 2.4 h was one of the shortest-lived mRNA studied and is the most unstable of the cytochrome P450 mRNAs we have tested. The rapid decay of CYP1A1 mRNA is associated with a rapid loss in poly(A) tail length, suggesting that deadenylation is the first step in the decay pathway. The short half-life appears to be conserved across species, which suggests that this characteristic of the CYP1A1 mRNA is important for its function.

3' Untranslated Regions↗