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Biomedical subjects

T K Lee

Publications and source records attributed to T K Lee.

At least 145 records · Page 8Linked to original sources
PubMed1990

Secondary prevention of ischemic stroke with low dose acetylsalicylic acid.

In order to evaluate the efficacy of low dose acetylsalicylic acid (ASA) for the secondary prevention of ischemic stroke, this cooperative multicenter clinical trial was conducted on a non-blind basis. Patients having a first transient ischemic attack (TIA), reversible ischemic neurological deficit (RIND) or completed ischemic stroke were eligible for this trial. A total of 590 patients including 47 cases of TIA, 23 cases of RIND and 520 cases of completed stroke entered this study. These patients were allocated by the time of admission to one of the following 5 trial regimens: (1) vasodilators having no known inhibitory effect on platelet function (control group), (2) dipyridamole (DP) 50 mg 3 times a day (DP group), (3) ASA 300 mg once a day (ASA 300 mg group), (4) ASA 300 mg once in combination with DP 50 mg 3 times a day (ASADP group), and (5) ASA 100 mg once a day (ASA1 group). No difference in effect between the control and DP groups was observed, nor between the ASA 300 mg and ASADP groups. Therefore, we combined the control and DP groups to make a non-ASA group, and joined the ASA 300 mg and ASADP groups to make an ASA3 group. The differences in the cumulative event-free rate appeared to be significant between the non-ASA group and the ASA3 group and also between the non-ASA group and the ASA1 group. But the frequency distribution of age, territory of stroke, diabetes mellitus, cardiac disease, hematological disease and hyperuricemia were significantly different among these 3 study groups. We thus included these covariates in the Cox's proportional hazard model to control their possible confounding effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Implications of nuclear diameter in small cell lung carcinoma.

The nuclear diameter of 5,117 malignant cells from 42 small cell lung carcinoma (SCLC) patients was assessed either on pretreatment tissue sections (35 cases) or cytologic smears (7 cases) by ocular micrometry. The SCLCs were subtyped as 30 oat cell carcinomas and 12 intermediate cell carcinomas according to the World Health Organization classification, based on the predominant histology of the tumor. The median number of nuclei measured from each patient was 110. All patients were treated identically by sequential hemibody and local irradiation combined with chemotherapy and had a median follow-up time of 310 days. The mean nuclear diameter (+/- standard error) obtained from tissue sections was 8.2 +/- 0.03 microns (median = 8.0), including 7.3 +/- 0.03 microns (median = 7.0) for oat cell cases and 9.5 +/- 0.06 microns (median = 9.0) for intermediate cell cases (P less than .001). In 28.6% of these patients, the nuclear diameter overlapped in the range of 8 microns to 9 microns between both subtypes. Comparisons between the nuclear diameter of primary and metastatic SCLC cells revealed no statistically significant differences. The nuclear diameter of malignant cells correlated with the mitotic index and stage of disease, but did not correlate with the other nuclear morphologic variables or with survival. The only identified prognostic factor was the stage of disease; these results indicate that the nuclear diameter of malignant cells should not be considered a prognosticator or a guide for therapy in SCLC patients.

Adult↗
PubMed1990

Overlap of nuclear diameters in lung cancer cells.

The nuclear diameters (NDs) of randomly selected malignant cells from 35 cases of small-cell lung cancer (SCLC; 4,370 nuclei) and 31 cases of non-SCLC (NSCLC; 1,280 nuclei) were measured on the pretreatment tissue sections by ocular micrometry. The mean ND (+/- standard deviation) of malignant cells for SCLC patients was 8.1 +/- 1.5 microns; these cases included 23 oat-cell carcinomas and 12 intermediate-cell carcinomas. The ND of malignant cells for NSCLC patients was 12.8 +/- 2.2 microns; these cases included 17 squamous-cell carcinomas, 12 adenocarcinomas and 2 large-cell carcinomas. The differences of ND between SCLC and NSCLC and between intermediate-cell cancer and NSCLC were highly significant (P = 0.001). However, the malignant cells of 36 (54.5%) of the 66 lung cancer patients had NDs that overlapped in the range of 8 microns to 13 microns. For the 12 intermediate-cell patients, the NDs of the malignant cells overlapped with those of 8 (66.7%) of the 12 adenocarcinomas and 10 (58.8%) of the 17 squamous carcinomas. In contrast, the NDs of only 5 (21.7%) of the oat-cell patients overlapped with those of 5 (41.7%) of the 12 intermediate-cell cases and showed no overlap with NSCLC cases. Since there is overlapping of the nuclear diameters of malignant cells between SCLC and NSCLC patients, nuclear parameters other than the diameter are necessary to differentiate these two major histologic types of lung cancers.

Carcinoma, Non-Small-Cell Lung↗
PubMed1990

Implication of nuclear morphological characteristics in small cell lung cancer.

We report the pretreatment quantitative nuclear morphological findings of malignant cells from 42 patients with small cell lung cancer (SCLC) to evaluate their impact on the stage of disease, therapeutic response and survival as well as their interrelationships. The variables analysed were nuclear configuration, distinction of nuclear membrane, chromatin and its distribution, mitotic index and nucleolar index. All patients were treated uniformly with chemotherapy and hemibody irradiation. The series consisted of 30 OAT cell cancers and 12 intermediate cell cancers, according to the World Health Organization histological subclassification of SCLC. The morphological analysis used histological (n = 35) and cytological (n = 7) slides from either primary (n = 30) or metastatic (n = 12) tumors. A total of 5117 cancer nuclei (median = 110 per patient) were assessed. The SCLC subtype was significantly associated with a specific nuclear chromatin pattern, mitotic index and stage of disease. However, none of the evaluated nuclear morphological variables or the SCLC subtypes had therapeutic or survival impact. The stage of disease was the only factor which significantly correlated with the survival of SCLC patients.

Adult↗
PubMed1989

Morphometric and morphologic evaluations in stage III non-small cell lung cancers. Prognostic significance of quantitative assessment of infiltrating lymphoid cells.

This study evaluated data from 30 non-small cell lung cancer (NSCLC) patients to determine whether demographic, clinical, and morphologic and morphometric data that were obtained prior to treatment, could be used to predict survival. All patients had Stage III disease, and all subsequently were treated identically with concurrent radiotherapy, cisplatin, and 5-fluorouracil. The series consisted of 18 squamous carcinomas, eight adenocarcinomas, and four large cell carcinomas. Morphometric measurements of randomized selected cancer cells per case included diameter of cytoplasm, nuclei, and nucleoli. Morphologic parameters evaluated were mitotic index, histologic differentiation, and pattern of nuclear chromatin of cancer cells, and the degree of necrosis and fibrosis of tumor tissue. The lymphoid and neutrophil index defined as the ratio of lymphoid cells and neutrophils to cancer cells from randomized microscopic fields (median = 25) at 400 x magnification were also determined. Our study indicated that the peritumor lymphoid index was the only factor significantly associated with the length of survival. The correlation coefficient (Pearson r) of these two factors was 0.5 (P less than 0.005). The median survival time of patients with peritumor lymphoid index less than 3 and greater than or equal to 3 was 95 days and 376 days, respectively (Kaplan-Meier estimation). The peritumor lymphoid index was an independent prognosticator of clinical outcome of Stage III NSCLC patients, and did not correlate with any of the other parameters analyzed.

Adenocarcinoma↗
PubMed1989

Redesigning a sweet protein: increased stability and renaturability.

Monellin is one of two natural proteins from African berries with potent sweet taste. Monellin is the smaller of the two, and consists of two peptides. The protein loses sweetness when heated above 50 degrees C under acidic pH. Based on the crystal structure of monellin we have fused the two chains into a single chain using several different linkers copied and 'transplanted' from the same molecule. One of the newly designed proteins is as potently sweet as the natural one, is more stable upon temperature or pH changes, and renatures easily even after heating to 100 degrees C at low pH.

Amino Acid Sequence↗
PubMed1989

Indolent glioma: a cause of epilepsy.

We studied eight patients with indolent gliomas. In all eight cases, despite characteristic radiological features, there was a delay in diagnosis because of misinterpretation of the initial computed tomogram. These tumours are an important cause of epilepsy of childhood, and surgery may well alleviate the epilepsy and possibly achieve a long term 'cure'. Therefore it is important that a diagnosis is made early and the lesion completely excised.

Astrocytoma↗
PubMed1989

Persistent CSF leucocytosis associated with intrathecal gentamycin.

A case where the administration of intrathecal gentamycin, used to treat a ventriculitis consequent upon a ventriculoperitoneal shunt infection, with a persistent elevation of the CSF leucocyte count is described. In a situation where the number of white cells in the CSF is taken to indicate resolution of infection, it is important to recognise that apparent failure of resolution of infection may be due to the gentamycin itself and not persistent infection.

Brain Diseases↗
PubMed1989

Clinical significance of combined antinuclear and anticytoplasmic antibodies detected by immunofluorescence.

Anti-nuclear antibodies (ANA) combined with anti-cytoplasmic antibodies (ACA) in 0.6% (n = 43) of 7,121 consecutive patients referred for ANA screening were observed. Homogeneous/cytoplasmic was the most frequently combined ANA/ACA pattern among 6 different indirect immunofluorescent (IF) combinations. Distribution of diseases was similar in patients with ANA/ACA and those controls with ANA alone. However, the ANA/ACA results were often transitory, especially in systemic lupus erythromatosus (SLE). The appearance of transitory ANA/ACA combinations on serial ANA testing may be useful as a serologic marker for SLE.

Adult↗
PubMed1989

Effect of estrogen on platelet aggregation in guinea pigs.

This experiment was carried out to explore the effect of estrogen on platelet aggregation, using Hartly strain guinea pigs. For the in vivo experiments, estradiol benzoate 1 mg/kg or 4 mg/kg was injected into male guinea pigs to observe the effects of this drug on platelet aggregation. In vitro studies were performed by incubating platelet-rich plasma with estradiol benzoate for 30 minutes at 37 degrees C. Aggregation was induced by the addition of aggregating agents: adenosine diphosphate (ADP, lobster or rabbit muscle, Merck), and collagen (calf skin, Bio-Data). The change in transmittance at 660 nm was recorded using NKK HEMA TRACER 1, model PAT-4A (Nippon Denshi Kagaku Co., Japan). Our results revealed that a 1 mg/kg injection of estrogen had a statistically significant suppressive effect on both ADP and collagen-induced platelet aggregation. While in the group with the 4 mg/kg injection of estrogen, this suppressing effect was not significant. In vitro studies by incubating platelet-rich plasma with estradiol had no inhibitory effect on aggregation induced by both ADP and collagen.

Adenosine Diphosphate↗
PubMed1988

Inhibitory effect of acetylsalicylic acid on platelet function in patients with completed stroke or reversible ischemic neurologic deficit.

The purpose of our study was to investigate the effects of different doses of acetylsalicylic acid on platelet aggregation. Among inpatients of the National Taiwan University Hospital, 236 cases of completed stroke and seven cases of reversible ischemic neurologic deficit that were diagnosed by computed tomography of the brain and that had not ingested acetylsalicylic acid or acetylsalicylic acidlike drugs for greater than 2 weeks before admission were selected for this study. Thromboxane B2 and 6-keto-PGF1 alpha were measured by radioimmunoassay, threshold concentration of adenosine diphosphate was measured by Born's method, and circulating platelet aggregates were measured by the method of Wu and Hoak. Various single doses of acetylsalicylic acid (75, 300, or 600 mg) or 300 mg acetylsalicylic acid every 6 hours for four doses or one dose of 300 mg acetylsalicylic acid with 75 mg dipyridamole significantly suppressed the mean plasma thromboxane B2 concentrations and elevated the mean adenosine diphosphate threshold concentrations. Abnormal plasma thromboxane B2 concentrations, adenosine diphosphate threshold concentrations, or circulating platelet aggregate ratios were significantly normalized after administration of these regimens. The effects were not significantly different among treatment groups. Forty milligrams of acetylsalicylic acid seemed to have less platelet-inhibitory effect. A single dose of 75 mg acetylsalicylic acid significantly inhibited platelet hyperfunction and effectively corrected the abnormal plasma thromboxane B2 concentrations, adenosine diphosphate threshold concentrations, and circulating platelet aggregate ratios. Higher doses did not enhance the inhibitory effect. In addition, this single dose of acetylsalicylic acid did not significantly suppress plasma 6-keto-PGF1 alpha. We conclude that 75 mg acetylsalicylic acid per day is adequate to inhibit platelet hyperfunction.

Adenosine Diphosphate↗
PubMed1987

Comparison of the effect of acetylsalicylic acid on platelet function in male and female patients with ischemic stroke.

The aim of this study was to observe whether acetylsalicylic acid (ASA) had different effects in both sexes. Out of the ischemic stroke patients who were admitted to the National Taiwan University Hospital (NTUH), those who had not taken ASA or ASA-like drugs for more than 2 weeks were selected for this study. For the diagnosis of ischemic stroke, computed tomography (CT) of the brain was performed in all cases, and for differential diagnosis, other necessary procedures were employed in a few cases. The serum salicylate (SA) level was measured by Trinder's method, thromboxane B2 (TXB2) and 6-keto-PGF1 alpha by radioimmunoassay, threshold concentration of adenosine diphosphate (ADP) by Born's method, and circulating platelet aggregates (CPA) by Wu and Hoak's method. The present study showed that the means of serum SA levels after administration of the same dose of ASA were not significantly different between the two sexes. After ingestion of ASA, a single dose of 75 mg, 300 mg or 600 mg, or 300 mg 4 times a day, mean plasma TXB2 levels were significantly suppressed and mean threshold concentrations of ADP were significantly elevated in the two sexes. After administration of above-mentioned various doses of ASA, the abnormally high plasma TXB2 levels and abnormally low threshold concentrations of ADP and CPA ratios were significantly normalized in both male and female patients. Plasma 6-keto-PGF1 alpha levels were not influenced by ingestion of ASA 75 mg, but significantly depressed by administration of ASA 300 mg in both sexes. There were no sex differences in the antiplatelet effect of ASA in this experiment.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

The significance of nuclear diameter in the biologic behavior of thyroid carcinomas: a retrospective study of 127 cases.

The relationship between nuclear diameter and biologic behavior was studied in 127 cases of thyroid carcinoma. Using a sonic digitizer coupled to a minicomputer, nuclear diameters of 200 randomly selected cancer cells from each case (hematoxylineosin-stained paraffin sections) projected at X 400 magnification were traced and averaged. A total of 25,400 measurements were made. The nuclear diameters varied from 4.7 to 13.1 micron. By analysis of variance, the nuclear diameters were significantly different (p = 0.0007) among the four types of thyroid cancers, being largest in the undifferentiated cancers (8.7 +/- 0.8 micron) and smallest in the medullary cancers (6.6 +/- 0.1 micron). Nuclear diameter was also significantly correlated with degree of tumor differentiation (p = 0.002), maximal tumor diameter (p = 0.03), mitotic rate (p = 0.002), and 5-year survival (p less than 0.05) for all types of tumors. The correlation between nuclear diameter and disease stage was significant only for undifferentiated cancers (p = 0.04). No significant correlations were seen between nuclear diameter and duration of disease, sex, or age of the patient.

Adolescent↗