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Biomedical subjects

C J Lee

Publications and source records attributed to C J Lee.

At least 55 records · Page 3Linked to original sources
PubMed2001

Aggressive epithelial odontogenic ghost cell tumor in the mandible: CT and MR imaging findings.

We report a case of aggressive epithelial odontogenic ghost cell tumor arising from the mandible in a 32-year-old man. On CT and MR studies, the tumor was seen as a large, heterogeneous soft-tissue mass that caused marked destruction of the mandible and invaded the mouth floor and tongue base. The tumor displayed a variety of densities and signal intensities on CT and MR images, which correlated well with the degree of cellularity of epithelial islands, abundance of ghost cells and eosinophilic materials, calcification, and cystic areas on histologic sections. Owing to the unpredictable biological behavior of this type of tumor, careful, long-term follow-up is highly recommended.

Adult↗
PubMed2001

Primary tubercolous osteomyelitis of the sternum.

We present an 82-year-old woman with anterior sternal pain diagnosed as primary mycobacterial osteomyelitis of the sternum. She was treated with simultaneous wide resection and reconstruction of the chest wall. On admission, computed tomographic scan showed a sclerotic sternal mass with soft tissue reaction. Mycobacterium tuberculosis was grown in initial culture. First-line antituberculous medication and local debridement failed. The successful result was achieved by extensive sternal and chondral resection followed by simultaneous bilateral pectoralis major muscle flap positioning.

Aged↗
PubMed2000

Rapid induction of senescence in human cervical carcinoma cells.

Expression of the bovine papillomavirus E2 regulatory protein in human cervical carcinoma cell lines repressed expression of the resident human papillomavirus E6 and E7 oncogenes and within a few days caused essentially all of the cells to synchronously display numerous phenotypic markers characteristic of cells undergoing replicative senescence. This process was accompanied by marked but in some cases transient alterations in the expression of cell cycle regulatory proteins and by decreased telomerase activity. We propose that the human papillomavirus E6 and E7 proteins actively prevent senescence from occurring in cervical carcinoma cells, and that once viral oncogene expression is extinguished, the senescence program is rapidly executed. Activation of endogenous senescence pathways in cancer cells may represent an alternative approach to treat human cancers.

Animals↗
PubMed2000

Genetic polymorphisms of p53 and GSTP1,but not NAT2,are associated with susceptibility to squamous-cell carcinoma of the esophagus.

The interaction of genetic and environmental factors can determine an individual's susceptibility to various cancers. We present a hospital-based case-control study, which included 90 patients of esophageal squamous-cell carcinoma (ESCC) and 254 healthy people in Taiwan, to investigate the effects of genetic polymorphisms of p53, GSTP1 and NAT2 on the risk of ESCC. Polymorphisms of p53, NAT2 and GSTP1 were determined by PCR-RFLP. The codon 72 p53 Pro allele was more frequently found in ESCC patients [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.04-3.35 for Arg/Pro genotype and OR 2.56, 95% CI 1.29-5.08 for Pro/Pro genotype]. In cigarette smokers, the frequency of GSTP1 Ile/Ile genotype was higher in ESCC patients (OR 2.8, 95% CI 1.4-5.7). Among alcohol drinkers, borderline significance was also found for GSTP1 Ile/Ile genotype (OR 2.0, 95% CI 0.9-4.4). Results were not similar for the NAT2 genetic polymorphism. Using logistic analyses, we found that individuals with p53 Pro/Pro genotype had a significantly higher risk of developing ESCC than those with Arg/Arg genotype (OR 2.3, 95% CI 1. 1-5.1), after adjusting for other significant environmental risk factors. This result remained similar (OR 2.2, 95% CI 1.0-4.8 for p53 Pro/Pro vs. Arg/Arg), even after further adjustment for NAT2 and GSTP1 polymorphisms. The codon 72 p53 Pro/Pro genotype in the general population and GSTP1 Ile/Ile in cigarette smokers may predict a higher risk of developing ESCC.

Adult↗
PubMed2000

Natural and radiation-induced degeneration of primordial and primary follicles in mouse ovary.

The present study deals with the morphological changes of the degenerating primordial and primary follicles induced by gamma-radiation. Prepubertal female mice of 3 weeks old ICR strain were gamma-irradiated with the dose of LD(80(30)) (8.3 Gy). The ovaries were collected at 3, 6 and 12 h after irradiation. The largest cross-sections were prepared by histological semithin sections for microscopical observations. The ratio (%) of normal to atretic follicles decreased with time after the irradiation in primordial follicles and in primary follicles as well. At 6 h after irradiation, the number of degenerated primordial follicles increased. Germinal vesicles disappeared and lipid droplets increased in number. Granulosa cells became round in shape and apoptotic cells started to appear. The ooplasmic membrane was not recognizable. The ratio of normal to atretic primordial follicles in the control group was 62.5. Then it became lower with time after the irradiation. It went down to 51.6, 49.0, 11.1 and 7.1 at 0, 3, 6 and 12 h, respectively. The ratio of normal to atretic primary follicles in the control mouse ovary was 81.3. It was 80.0, 75.0, 45.5 and 33. 3 at 0, 3, 6 and 12 h after irradiation, respectively. It is concluded that the ionizing radiation acutely induces the degeneration of primordial and primary follicles. The pattern of degeneration is one of the following: (1) apoptosis of one or more granulosa cells with a relatively intact oocyte, (2) apoptosis of an oocyte with intact follicle cells, or (3) apoptotic degenerations of both kinds of cells. These results can provide morphological clues for the identification of the degenerating primordial and primary follicles in normal and irradiated mouse ovaries.

Animals↗
PubMed2000

Effect of exogenous melatonin on the ovarian follicles in gamma-irradiated mouse.

The present study was performed to obtain the evidence of the radioprotective function of melatonin on gamma-radiation-induced follicular atresia in mouse ovary. Three-week-old immature mice received 10 and 100 microg of melatonin dissolved in 100 microl of the alcoholic saline. Two hours after the treatments, they were whole-body irradiated with a dose of LD(80(30)) (8.3 Gy). The ovaries were dissected out of the animals at -2, 2, 8, 14 h after the onset of irradiation. The total number of follicles including the normal and atretic follicles examined in the largest cross sections was 125. The number was reduced to 103 in the irradiated group. The number of primordial follicles of the irradiation group or the melatonin-treated group was smaller than that of the control group. However, the number of primary, preantral, and antral follicles was not different from that of the control group. In the group pretreated with 100 microg of melatonin before irradiation, the ratio of normal primordial follicles was significantly higher than that of the irradiation group at any time point after irradiation. The high concentration of melatonin also reduced the radiation-induced degeneration of the primary follicles at 14 h after irradiation. On the other hand, the pretreatment of 10 microg of melatonin had little or no effect on the radiation-induced degeneration of primary follicles. However, it gave a protective effect on the radiation-induced degeneration in the primordial follicles at 2 h after irradiation, and 14 h after irradiation in preantral and antral follicles. From the above results, it is concluded that the exogenous melatonin has different functions depending on the follicle stages, and that the radioprotective effect of exogenous melatonin on the follicular degeneration is related to its concentration.

Animals↗
PubMed2000

Pentobarbital and ketamine suppress serum concentrations of sex hormones in the female rat.

PURPOSE: To investigate the potential effects of pentobarbital and ketamine on serum concentrations of sex hormones, the present study was performed using pregnant mare serum gonadotropin (PMSG)-primed cyclic female Sprague-Dawley rats. METHODS: Pentobarbital sodium (37 mg.kg(-1), i. p.) or ketamine-hydrochloride (229 mg.kg(-1), i. m.) was injected 2 and 3 days after PMSG treatment. At 0, 1, 2, 3, 4, and 5 days after PMSG treatment, sera were collected by cardiac puncture. The serum concentrations of progesterone (P(4)), testosterone (T), and estradiol-17 beta (E(2)) were determined by radioimmunoassay. RESULTS: The serum concentrations of P(4) tended to be lower in both the pentobarbital- and the ketamine-treated groups compared with the control group. Significant differences were found on days 3 and 4 after pentobarbital and on days, 1, 4, and 5 after ketamine administration. Serum concentrations of T were also suppressed in both the pentobarbital and the ketamine-treated groups, whereas E(2) concentrations decreased only in the ketamine-treated group. CONCLUSION: Pentobarbital and ketamine decrease serum sex hormone concentrations in PMSG-primed female rats.

Journal Article↗
PubMed2000

Risk factors for pre-eclampsia in an Asian population.

OBJECTIVE: To identify the risk factors for pre-eclampsia in an Asian population. METHOD: We conducted a retrospective cohort study involving 29375 Taiwanese women who delivered between July 1990 and September 1998, excluding pregnancies complicated by chronic hypertension or fetal malformations. RESULT: Four hundred and fifteen women had pre-eclampsia (1.4%). Women who had a history of pre-eclampsia (OR 6.3, 95% CI 4.4, 9.2), multiple gestation (OR 3.6, 95% CI 2.4, 5.5), a prepregnancy BMI > 24.2 kg/m(2) (OR 2.4, 95% CI 1. 8, 3.1), were > 34 years of age (OR 1.8, 95% CI 1.4, 2.4), nulliparous (OR 1.3, 95% CI 1.2, 1.5), had urinary tract infection (OR 4.8, 95% CI 1.5, 15.8), or worked during pregnancy (OR 1.9, 95% CI 1.4, 2.4) were at increased risk of pre-eclampsia. CONCLUSION: Some of the risk factors for pre-eclampsia among Asian women are the same as those of other ethnic groups, whereas some of the risk factors are different.

Adult↗
PubMed2000

Genome-wide analysis of single-nucleotide polymorphisms in human expressed sequences.

Single-nucleotide polymorphisms (SNPs) have been explored as a high-resolution marker set for accelerating the mapping of disease genes. Here we report 48,196 candidate SNPs detected by statistical analysis of human expressed sequence tags (ESTs), associated primarily with coding regions of genes. We used Bayesian inference to weigh evidence for true polymorphism versus sequencing error, misalignment or ambiguity, misclustering or chimaeric EST sequences, assessing data such as raw chromatogram height, sharpness, overlap and spacing, sequencing error rates, context-sensitivity and cDNA library origin. Three separate validations-comparison with 54 genes screened for SNPs independently, verification of HLA-A polymorphisms and restriction fragment length polymorphism (RFLP) testing-verified 70%, 89% and 71% of our predicted SNPs, respectively. Our method detects tenfold more true HLA-A SNPs than previous analyses of the EST data. We found SNPs in a large fraction of known disease genes, including some disease-causing mutations (for example, the HbS sickle-cell mutation). Our comprehensive analysis of human coding region polymorphism provides a public resource for mapping of disease genes (available at http://www.bioinformatics.ucla.edu/snp).

Base Sequence↗
PubMed2000

Degeneration of the acetabular cartilage in osteonecrosis of the femoral head: histopathologic examination of 15 hips.

Acetabular cartilage with subchondral bone was taken from the superior dome from 15 hips of 13 patients undergoing total hip arthroplasty due to osteonecrosis of the femoral head. The mean age of the patients was 40 years. There were 10 hips ARCO stage IIIA, and 5 hips stage IIIB. 3 of the cases were mild, 12 moderate, and 1 had severe arthrosis. The degree of collapse of the femoral head was significantly related to the degeneration of the acetabular cartilage on histological examination. Our observations support the view that patients with an ARCO Stage III hip do not benefit from head-preserving procedures. They may also explain why bipolar prosthesis gives poorer results than total hip arthroplasty, in cases of osteonecrosis of the femoral head.

Acetabulum↗
PubMed2000

Pneumosinus dilatans multiplex, mental retardation, and facial deformity.

Pneumosinus dilatans is a term used to describe enlargement of one or more paranasal sinuses without radiological evidence of localized bone destruction, hyperostosis, or mucous-membrane thickening. To date, many cases have been reported that involved frontal, ethmoid, sphenoid, and maxillary sinus. However, no case has been reported that involved all paranasal sinuses. Our case involved mastoid air cells as well as all paranasal sinuses. It is named pneumosinus dilatans multiplex by us. This is the first case to be reported in English literature that has this syndromic condition of pneumosinus dilatans multiplex, mental retardation, and facial deformity.

Adult↗
PubMed2000

Structure determination of porcine haemoglobin.

To investigate a potential candidate material for making artificial red blood cells to supplement blood transfusion, the X-ray structure of porcine haemoglobin at 1.8 A resolution was determined as part of research towards synthesizing human blood. Porcine haemoglobin was crystallized by the vapor-diffusion method, producing crystals of dimensions 0.3-0.5 mm after successive seeding. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 68.10, b = 72.27, c = 114.85 A. The initial phase was determined by the molecular-replacement method, using human oxyhaemoglobin as a model. The final R factor was 21.1% for 36 820 reflections after validation of 574 water molecules. The r.m.s. deviations of bond lengths, angles, torsion angles and improper angles from their ideal values are 0.017 A, 3.0, 20.6 and 1.8 degrees, respectively. The average B factor is 33.63 A(2) for the haemoglobin molecule and 50.53 A(2) for the water molecules. The structure could be superimposed on a 2.8 A resolution structure with an r.m.s. difference of 0.59 A in main-chain atomic positions and 1. 27 A in side-chain atomic positions. Porcine and human haemoglobins are compared. A tentative model for artificial blood is proposed based on the complementarity relationship of the surface charges between haemoglobin and the surrounding cell membrane.

Amino Acid Sequence↗
PubMed2000

Analgesic effect of electric stimulation of peripheral nerves with different electric frequencies using the formalin test.

Although electroacupuncture (EA) has been widely used to treat pain, the optimal frequency of EA therapy remains unclear. The study sought to determine the effect of different EA frequencies in a Sprague-Dawley (SD) rat model of pain. Electric stimulation (ES) at frequencies of 2 Hz, 15 Hz or 100 Hz was applied to the ipsilateral or contralateral sciatic nerve of the injected hindpaw of SD rats. Formalin (50 microl, 5%) was subcutaneously injected into the plantar surface of the left hindpaw to induce a nociceptive response. Behavior, including licking and biting, was observed to have two distinct periods, an early phase during the first 5 mins and a late phase from 21-35 mins after injection. The total biting or licking count served as an Indicator of nociceptive response. Our results indicate that ES of the ipsilateral sciatic nerve at a frequency of 2 Hz or 15 Hz reduced the nociceptive responses in both the early and the late phases of the formalin test, whereas ES at 2 Hz had greater antinociceptive effect than ES at 15 Hz in the early phase. No similar analgesic effect in the early phase was observed for ES at 100 Hz. Both pretreatment with ES at 2 Hz and naloxone (3 mg/kg, s.c.) produced a greater antinociceptive response in the late phase than when ES at 2 Hz was delivered immediately after formalin administration. In addition, ES of the neck muscle or contralateral sciatic nerve at a frequency of 2 Hz also decreased licking and biting activity in both phases. The results of this study indicate that different analgesic mechanisms are involved in the response to ES at frequencies of 2 Hz, 15 Hz and 100 Hz, and that ES at 2 Hz has a greater analgesic effect on formalin-induced nociceptive response, especially when it is delivered prior to the onset of pain. The analgesic effect of ES may be mediated via a central origin in the supraspinal level. These findings suggest that 2 Hz may be a good frequency selection for clinical EA applications in analgesia, and that pretreatment with EA at 2 Hz may be an effective method to treat post-operative pain.

Analgesia↗
PubMed2000

Reduction of electrically evoked neural activity by ginseng saponin in rat hippocampal slices.

It is well established that ginseng saponin has positive influences on various neural diseases, but little is known about its electrophysiological effects in the central nervous system. In this study, we examined the electrophysiological effects of ginseng saponin in rat hippocampal slices. Total saponin from ginseng root reduced the slope of fEPSPs (field excitatory postsynaptic potentials) in the CA1 area in a dose-dependent manner (9.1 +/-5.4%, 48.4+/-12.1%, and 60.5+/-15.3% at 10, 50, and 100 microg/ml, respectively), which was reversed within 10 min of washout. Seven different ginsenosides resulted in varied degrees of fEPSPs reduction. The rank order of reduction was Rb1, Rg1 >Rg2, Rh1, Rc>Rd, Re within a range of 5-64% reduction. No difference in the suppressive action between protopanaxadiol (Rb1, Rc, Rd) and protopanaxatriol (Rg1, Rg2, Re, Rh1) saponins was shown; the slope of fEPSPs was reduced by 38% and 40% on average, respectively. The possible role of gamma-aminobutyric acid (GABA(A)) receptor in the suppressive action of ginseng saponins was tested using whole cell patch recording in acutely isolated hippocampal neurons. Ginsenosides did not induce chloride current nor modified GABA-induced current. Also, the suppressive effect of ginsenosides on fEPSPs was still observed in the presence of the GABA(A) receptor antagonist, bicuculline methiodide 50 microM. These results suggest that the suppressive effect is not attributable to regulation of GABA(A) receptor activation.

Animals↗