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Biomedical subjects

M C Lee

Publications and source records attributed to M C Lee.

At least 325 records · Page 18Linked to original sources
PubMedDate not supplied

Glucose-sensitive holographic sensors.

Holographic sensors for monitoring glucose were fabricated from hydrogel films containing chemical ligands based on phenylboronic acid. The films were transformed into reflection holograms using a diffusion method coupled with exposure to laser light. The diffraction wavelength of the holograms was used to monitor the swelling of the hydrogel film in the presence of glucose. Fully reversible changes in diffraction wavelength were demonstrated, highlighting the potential for using these holograms as glucose sensors.

Biosensing Techniques↗
PubMedDate not supplied

Development of a method for measuring myocardial contractility with gated myocardial SPECT and arterial tonometry.

BACKGROUND: Gated myocardial single photon emission computed tomography (SPECT) and radial artery applanation tonometry were used, respectively, to quantify the time-volume curve of the left ventricle and to estimate ventricular pressure wave. We developed ways of determining end-systolic elastance (Ees) with the normalized-single-beat method and tested the reproducibility of these measurements. METHODS AND RESULTS: In patients with coronary artery disease (male/female = 33:2, age 66 +/- 10 years, ejection fraction 22% to 77%), rest thallium-201 gated/poststress technetium-99m sestamibi gated SPECT/24-hour rest Tc-99m sestamibi gated SPECT and arterial tonometry were performed. Quantitative gated SPECT software yielded a systolic time-volume curve, and tonometrically measured radial artery pressure wave yielded central aortic pressure wave. With systolic half of pressure-volume curve, void volume (Vo) was estimated and Ees was calculated. Over 71 measurements Ees ranged from 1.7 to 5.3 and Vo from -4 to 200 mL. Ejection duration, other indexes of central pressure waveform, end-diastolic volume, end-systolic volume, and ejection fraction were reproducible. The reproducibility of Vo was excellent (r = 0.97). Ees at rest (n = 15) showed fair reproducibility between Tc-99m-sestamibi and TI-201 SPECT (r = 0.51). CONCLUSION: With gated myocardial SPECT, a noninvasive method of quantifying myocardial global contractility was developed. Reproducibility of this measurement was sufficient for use in clinical routine. Ees measured by this method warrants validation by invasively measured Ees.

Aged↗
PubMedDate not supplied

Stress selectively increases fos protein in dopamine neurons innervating the prefrontal cortex.

Stress-induced alterations in expression of c-fos protein (Fos) in mesencephalic dopamine (DA) neurons of the rat were examined in order to discern which midbrain DA neurons are metabolically activated by stress. Restraint stress for 30 min increased the number of DA neurons exhibiting Fos-like immunoreactivity in the ventral tegmental area (VTA), but not in the substantia nigra or retrorubral field. Stress elicited an increase in the number of DA neurons expressing Fos in specific nuclei within the VTA. Administration of the anxiogenic beta-carboline FG 7142 also increased the total number of VTA DA neurons expressing Fos protein, whereas pretreatment with an anxiolytic benzodiazepine (diazepam) partially prevented the stress-induced increase in Fos expression. Restraint stress for 30 min increased concentrations of the DA metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the nucleus accumbens and striatum, as well as in the prefrontal cortex. Retrograde tracer studies revealed that stress increased Fos protein expression in a distinct subset of DA neurons projecting to the prefrontal cortex. In contrast, Fos expression was not increased in any DA neurons projecting to the nucleus accumbens. The present data indicate that there are at least two functionally distinct DA systems embedded within the prefrontal cortex of the rat.

Animals↗
PubMedDate not supplied

Expression of cyclooxygenase-2 in epithelial ovarian tumors and its relation to vascular endothelial growth factor and p53 expression.

The purpose of this study was to evaluate cyclooxygenase-2 (COX-2) expression in epithelial ovarian tumors and its correlation with vascular endothelial growth factor (VEGF) and p53 expression. Immunohistochemical studies with anti-COX-2, anti-VEGF, and anti-p53 antibodies were carried out in 54 malignant and 23 borderline epithelial ovarian tumors. Elevated COX-2 expression was detected in 77.8% of ovarian carcinomas, which was significantly higher than that of borderline tumors (26.1%) (P < 0.001). In ovarian carcinomas, there was no significant correlation between COX-2 expression and other clinicopathologic features. Elevated VEGF expression was detected in 74.1% of ovarian carcinomas, and p53 expression was found in 64.8% of ovarian carcinomas. COX-2 expression was statistically correlated with elevated VEGF expression (P < 0.001) and p53 positivity (P < 0.05). On a univariate analysis, FIGO stage (P < 0.0001), histologic type (P= 0.0104), and COX-2 expression (P= 0.0135) were significant prognostic factors for overall survival. In a multivariate analysis, FIGO stage (P < 0.0001) was the only independent prognostic factor for poor survival. These findings suggest that COX-2 may play a role in the progression of epithelial ovarian tumors and that COX-2 expression may contribute to ovarian tumor angiogenesis by stimulating VEGF expression. p53 may be responsible for the regulation of COX-2 expression.

Adenocarcinoma↗
PubMedDate not supplied

Lymphonodular cryptococcosis diagnosed by fine needle aspiration cytology in hyper-IgM syndrome. A case report.

BACKGROUND: Most cases of cryptococcosis are diagnosed when signs of meningitis have appeared. We report a case of lymphonodular cryptococcosis that was diagnosed by fine needle aspiration cytology (FNAC), excisional biopsy of a cervical lymph node and culture of aspirated material. CASE: An 11-year-old boy presented with a history of fever and enlarged bilateral cervical lymph nodes of two weeks' duration. Past medical history included immunoglobulin replacement for hyper-IgM syndrome for the previous eight years. FNAC smears from a cervical lymph node showed numerous yeasts of various sizes, ranging from 5 to 15 microns in diameter, located in the cytoplasm of multinucleated giant cells and in the background. In air-dried, Diff-Quik-stained slides, the yeasts stained blue and were surrounded by clear halos. Aspirated material collected in the syringe was cultured, and Cryptococcus neoformans was isolated. CONCLUSION: This case report suggests that a combination of FNAC and culture is a simple and useful method of diagnosing fungal infections. Early diagnosis by FNAC makes possible the early initiation of treatment.

Biopsy, Needle↗
PubMedDate not supplied

Diagnostic value of p53 protein and flow cytometric DNA analysis in the study of serous effusions.

OBJECTIVE: To investigate the diagnostic value of p53 protein and DNA analysis in the study of serous effusions. STUDY DESIGN: A total of 76 samples of serous effusions were studied by immunohistochemistry for p53 protein and flow cytometric (FCM) DNA analysis. The results were correlated with final cytologic diagnoses, which were confirmed by immunohistochemistry using antibodies against cytokeratin, carcinoembryonic antigen, epithelial membrane antigen and fibronectin. RESULTS: Final cytologic diagnoses included 28 malignant effusions and 48 benign effusions. No expression of p53 protein was seen in benign effusions. In contrast, p53 protein expression was seen in 19/28 (sensitivity 68%) malignant effusions. FCM detected aneuploid cells in 12/28 (43% sensitivity) of malignant and 0/46 of benign effusions. Immunohistochemical determination of p53 protein combined with FCM DNA analysis increased sensitivity to 79%. CONCLUSION: Immunohistochemical determination of p53 protein and FCM DNA analysis can aid in making an accurate and specific diagnosis of serous effusions, but the principal limitation of these tests is their relatively low sensitivity.

Aneuploidy↗
PubMedDate not supplied

Fine needle aspiration cytology of Langerhans cell histiocytosis confined to lymph nodes. A case report.

BACKGROUND: Lymph node involvement in Langerhans cell (LC) histiocytosis (LCH) can be seen as a component of the systemic form, or it may be the initial and sometimes exclusive manifestation of the disease. Descriptions of patients with LCH whose disease is confined to lymph nodes are rare. CASE: We present a case of LCH confined to lymph nodes initially diagnosed by fine needle aspiration (FNA) cytology in a 43-year-old male. The cytologic findings in LCH included high cellularity, isolated LCs with prominent nuclear indentations and grooves, multinucleate giant cells, eosinophils and lymphocytes. Confirmation of LCH was obtained by positive S-100 protein immunohistochemical staining and the demonstration of Birbeck granules on electron microscopy. CONCLUSION: The presence of LCs with prominent nuclear indentations and grooves is characteristic of LCH confined to lymph nodes and serves as a key point in suggesting the diagnosis of LCH.

Adult↗
PubMedDate not supplied

Immunohistochemical panel for distinguishing between carcinoma and reactive mesothelial cells in serious effusions.

OBJECTIVE: This study was designed to assess whether a new panel of antibodies is a useful adjunct in the differential diagnosis of carcinoma and reactive mesothelial cells. STUDY DESIGN: Complete, one-hour immunohistochemistry using antibodies against cytokeratin (CK), carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA) and fibronectin was applied to cell blocks from 76 pleural and peritoneal fluid specimens. Fifty patients with histologically diagnosed primary carcinomas and 26 without evidence of malignancy were included. The results were correlated with routine cytologic results. RESULTS: The final cytologic diagnoses were 28 malignant effusions and 48 benign effusions. CEA and EMA were present in 25 (89%) and 24 (86%) of 28 carcinoma cases, respectively. These determinants were absent from reactive mesothelial cells. Fibronectin strongly labeled reactive mesothelial cells, with no staining of carcinoma cells. Carcinoma cells expressed at least two antibodies to CK, CEA and EMA and were negative to fibronectin. Reactive mesothelial cells expressed both CK and fibronectin. In 6 of 28 carcinoma cases (21%) the immunohistochemical panel identified carcinoma cells that were not recognized initially on routine cytologic examination. CONCLUSION: A panel of CEA, EMA and fibronectin monoclonal antibodies appears to be suitable for distinguishing between carcinoma cells and reactive mesothelial cells in serous effusions.

Antibodies, Monoclonal↗
PubMedDate not supplied

Fine needle aspiration cytology of anaplastic carcinoma with osteoclastlike giant cells of the thyroid. A case report.

BACKGROUND: Multinucleated giant cells of osteoclastlike appearance are seen in some anaplastic carcinomas, but only three cases in which the diagnosis was made by aspiration cytology are reported in the international medical literature. CASE: A 66-year-old female presented with a history of a palpable neck mass. The diagnosis of fine needle aspiration cytology was anaplastic thyroid carcinoma with osteoclastlike giant cells. Immunohistochemical staining and DNA ploidy analysis were done. CONCLUSION: Osteoclastlike giant cells have an origin different from that of the anaplastic component. DNA aneuploidy was noted in our case.

Aged↗
PubMedDate not supplied

Cerebrospinal fluid in cerebral hemorrhage and infarction.

Cerebrospinal fluid (CSF) abnormalities were correlated with pathological diagnoses in 61 patients with autopsy-verified intracerebral hemorrhage or cerebral infarction. Lumbar punctures were performed within one week of onset of symptoms. The CSF color and red blood cell counts were the most useful CSF parameters in differentiating between intracerebral hemorrhage and cerebral infarction. In 75% of the patients with intracerebral hemorrhage, the CSF was either grossly bloody or xanthochromic; in 25%, the CSF was clear. In patients with cerebral infarction, the CSF was never grossly bloody; in two patients with hemorrhagic infarction, the CSF was xanthochromic. The CSF pressure, protein values and leukocyte counts were less useful in differentiating intracerebral hemorrhage from cerebral infarction. Cases with hemorrhagic infarction could not be separated from those with ischemic infarction on the basis of CSF analysis. In clear CSF, the polymorphonuclear neutrophilic leukocyte (PNL) counts were never greater than 20 per cubic millimeter. In xanthochromic or cloudy CSF, leukocyte counts, especially PNLs, were frequently elevated, occasionally to the high levels.

Cerebral Cortex↗