Search PubMed⌕ Search

Biomedical subjects

C C Hsieh

Publications and source records attributed to C C Hsieh.

At least 55 records · Page 3Linked to original sources
PubMed2000

Effects of continuous calcitonin treatment on osteoclasts derived from cocultures of mouse marrow stromal and spleen cells.

BACKGROUND: Continuous calcitonin (CT) treatment for bone diseases associated with increased bone resorption may be followed by prolonged depression of osteoclast response to CT. The mechanisms of this "escape" phenomenon remain unclear. METHODS: We examined the effects of continuous CT treatment on cell formation, calcitonin receptor (CTR) expression, response to CT, and bone resorption of osteoclasts in a coculture of mouse marrow stromal and spleen cells in the presence of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. Cells were cocultured and treated with salmon CT (sCT) for 7, 14, or 21 days. The effects of continuous CT treatment on osteoclast formation was determined by quantitation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs). CTR expression in osteoclasts was determined by binding of [125I]sCT in autoradiography. Bone resorption and CT responsiveness were assessed by examining the formation of resorption pits and by enumerating osteoclast reattachment on dentine slices after sCT rechallenge. RESULTS: TRAP-positive MNCs appeared in cocultures treated with sCT and were similar in number and morphology to those in control cultures, regardless of the concentration and duration of sCT treatment. A decrease in CTR expression was identified as a loss of silver grains from the TRAP-positive cells in cocultures receiving sCT treatment for 14 or 21 days. Partial recovery of CTR expression in TRAP-positive cells was evident in cocultures treated with sCT for only the first 7 days of coculture. TRAP-positive MNCs in cocultures treated with sCT for 14 or 21 days were resistant to the rechallenge with sCT. They attached to dentine slices and caused numerous resorption pits compared with control cells and cells treated with sCT for the first 7 days of coculture (p < 0.01). CONCLUSION: These findings suggest that the escape phenomenon that develops after continuous CT treatment may be due, at least in part to: 1) loss of responsiveness to CT in existing osteoclasts; and 2) development of new osteoclasts that are CTR-deficient and, therefore, refractory to CT rechallenge.

Animals↗
PubMed1999

Increased risk of lymphoid and nonlymphoid malignancies in patients with lymphomatoid papulosis.

BACKGROUND: Lymphomatoid papulosis (LyP) is a rare skin disease with malignant potential. The long term outcomes of patients with this disease have not been adequately assessed. METHODS: Fifty-seven patients with biopsy-proven LyP and 67 controls matched for age, gender, and race were followed prospectively from 1988 to 1996. Reported malignancies were confirmed by surgical pathology and/or autopsy reports. A search through the National Death Index through December 1995 was conducted to identify all deaths, and death certificates were procured. Expected numbers of malignancies based on SEER data were calculated for both the patient and the control groups. RESULTS: Six LyP patients (10.5%) and 1 control (1.5%) reported nonlymphoid malignancies (P = 0.047). Two patients and no controls developed lymphoid malignancies (mycosis fungoides and CD30(+) cutaneous lymphoma). The expected numbers of nonlymphoid and lymphoid malignancies in the LyP patient group, based on the SEER data, were 1.93 and 0.15, respectively, yielding a relative risk (with 95% confidence interval) of 3.11 (1.26-6.47) for nonlymphoid malignancies and 13.33 (2.24-44.05) for malignant lymphomas in the LyP patients. There was no significant difference between the observed and expected numbers of malignancies in the control group. Four LyP patients died during the follow-up, three due to malignancies; and one control died of a gunshot wound to the head (suicide). The difference in overall survival between the LyP patients and the controls was not statistically significant (P = 0. 12). CONCLUSIONS: Patients with LyP appear to have an increased risk of both lymphoid and nonlymphoid malignancies. The increased risk of nonlymphoid as well as lymphoid malignancies may suggest a basic underlying genetic defect leading to the development of malignancy in LyP patients.

Adolescent↗
PubMed1999

Risk factors for prostate cancer: a case-control study in Greece.

A case-control study of prostate cancer (PC) was undertaken in Athens, Greece. Cases were 320 patients with histologically confirmed incident disease, whereas controls were 246 patients without history or symptomatology of benign prostatic hyperplasia, treated in the same hospitals as the cases for minor diseases or conditions. Cases and controls had similar distributions with respect to height, body mass index, sibship size and birth order in the parental family, marital status and number of offspring in the subject's own family and a long series of previous surgical operations and medical diagnoses, including diabetes mellitus, hepatitis and sexually transmitted diseases. There was also no evidence for a positive association between vertex baldness, tobacco smoking and drinking of coffee or alcoholic beverages, on the one hand, and PC, on the other. There was evidence, however, that some aspect of urban life may increase the risk for PC and a suggestion that sexual activity in early adulthood may be inversely associated with this risk.

Age Factors↗
PubMed1999

Risk factors for placenta accreta.

OBJECTIVE: To identify risk factors associated with placenta accreta in a large cohort study. METHODS: Data for this study came from the Taiwan Down Syndrome Screening Group, an ongoing project on feasibility of serum screening in an Asian population. Women who had serum screening for Down syndrome at 14-22 weeks' gestation using alpha-fetoprotein (AFP) and free beta-hCG between January 1994 and June 1997, and delivered in the same institution, were included (n = 10,672). Those who had multiple gestations (n = 200), overt diabetes (n = 11), or fetal malformations (n = 101) were excluded. If a woman was involved more than once, one randomly selected pregnancy was included in the analysis (n = 9349). Twenty-eight pregnancies were complicated by placenta accreta, diagnosed by clinical presentation (n = 26) or histologic confirmation (n = 2). Multiple logistic regression with adjustment for potentially confounding variables was used to identify independent risk factors for placenta accreta. RESULTS: Women who had placenta previa (odds ratio [OR] 54.2; 95% confidence interval [CI] 17.8, 165.5) and second-trimester serum levels of AFP and free beta-hCG greater than 2.5 multiples of the median (OR 8.3; 95% CI 1.8, 39.3 and OR 3.9; 95% CI 1.5, 9.9, respectively), and were 35 years and older (OR 3.2; 95% CI 1.1, 9.4) were at increased risk of having placenta accreta. CONCLUSION: Risk factors for placenta accreta include placenta previa, abnormally elevated second-trimester AFP and free beta-hCG levels, and advanced maternal age.

Adult↗
PubMed1999

Estimating the ozone formation potential of volatile aromatic compounds in vehicle tunnels.

Two vehicle tunnels located in the Taipei area were selected to study the ozone formation potential of volatile aromatic compounds (VACs). Air samples in the two tunnels were collected using canisters. Analysis of VACs was conducted with a gas chromatograph equipped with a mass spectrometer. The total VOCs concentrations in Zefun tunnel ranged from 483.5 to 1032.2 (micrograms/m3) which increased with the increase in traffic volume. In the Lishin tunnel, the total VACs concentration ranged from 356.6 to 1961.3 (micrograms/m3) which was not well correlated with the traffic volume. The most predominant VACs in these vehicle tunnels were toluene and xylenes. Although the traffic volume and types of vehicles were not exactly the same, the characteristic ratios of the VACs concentrations were found to be similar. These results indicated that the existence of a specific characteristic ratio of VAC concentration was affected by the mobile sources. The maximum ozone formation potential resulted from the vehicles in the Lishin motorcycle tunnel which had higher values than the Zefun tunnel and much higher than the SPECIATE databases in the US via weighting the maximum incremental reactivity (MIR) scale.

Air Pollution↗
PubMed1999

Diet and benign prostatic hyperplasia: a study in Greece.

OBJECTIVES: To evaluate the nutritional etiology of benign prostatic hyperplasia (BPH) by conducting a case-control study in Athens, Greece. Despite the high morbidity and substantial human suffering produced by BPH, little research has been undertaken concerning the nutritional etiology of this disease. METHODS: The study sample consisted of 184 patients with histologically confirmed BPH and 246 control patients without clinical evidence of prostate disease. All patients and controls were permanent residents of the greater Athens area. The data were modeled through unconditional logistic regression. RESULTS: Among the food groups, fruits were inversely related to BPH risk, with a logistic regression-derived odds ratio of 0.79 per quintile increase and 95% confidence interval 0.67 to 0.93. Increased consumption of both butter and margarine was positively associated with BPH risk, and a marginally significant positive association was also evident for seed oils. No overall association was found with respect to consumption of olive oil. In analyses evaluating the role of nutrients rather than foods, zinc, an element selectively concentrated in the prostate gland, was significantly positively associated with BPH risk. CONCLUSIONS: Our study provides evidence that, among added lipids, butter and margarine may increase the risk of BPH, and fruit intake may reduce this risk. Dietary zinc may play an important role in the etiology of BPH.

Case-Control Studies↗
PubMed1999

Tea consumption: fluid intake and bladder cancer risk in Southern Taiwan.

OBJECTIVES: To determine whether tea consumption and intake of other beverages increases bladder cancer risk. METHODS: A case-control study was conducted in Kaohsiung, Taiwan between August 1996 and June 1997. Index patients studied were consecutive patients with histologically confirmed, newly diagnosed bladder cancer in two major hospitals. For each patient, 4 controls were selected from patients with non-neoplastic and nonurologic diseases undergoing surgical operations in the same hospital and individually matched by sex, age, and date of admission. Using a structured questionnaire, a trained interviewer interviewed 40 patients and 160 controls. Conditional logistic regression analysis adjusting for ethnicity, family history, and smoking status and matching variables were used to estimate the odds ratio (OR) and 95% confidence interval (CI). RESULTS: Tea consumption overall was associated with increased bladder cancer risk (OR 3.29, 95% CI 1.34 to 8.05). Compared with non-tea drinkers, the odds ratios of bladder cancer for oolong tea drinkers was 3.00 (95% CI 1.20 to 7.47); for non-oolong tea drinkers (black and/or other green tea), it was 14.86 (95% CI 2.13 to 103.83). The risk was greater among those who began to drink tea before age 40 (OR 9.50, 95% CI 2.39 to 37.75) and those who had been drinking tea for more than 30 years (OR 17.75, 95% CI 3.00 to 105.17). Coffee, tap water, and alcohol consumption were associated with a slightly increased risk, and both soy juice and rice juice consumption were associated with reduced risk; none of these odds ratio estimates were statistically significant, however. CONCLUSIONS: Our results suggest that tea consumption is associated with an increased risk of bladder cancer.

Aged↗
PubMed1999

Morphological alterations associated with the cytotoxic and cytostatic effects of citric acid on cultured human dental pulp cells.

Citric acid exerts potential harmful effects on the pulp when used for root surface demineralization, smear layer removal, and dentin etching. Using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, we found that incubation of cultured human dental pulp cells in medium containing 0.5% (pH 4.74) or 1.0% (pH 3.42) of citric acid for 2 h lead to 25% and 48% of cell death, respectively. Cytotoxicity of citric acid was associated with its acidity. Exposure of cells to pure 1% citric acid (pH 2.26) for 60 s lead to immediate cell death. Cytotoxicity was usually preceded by cell retraction, cell surface blebbing, and finally uptake of trypan blue, implicating the presence of cell membrane damage. A medium containing 0.05% citric acid can retard the growth of pulp cells. These results indicate that adequate protection of the pulp is important, especially when the remaining dentin is thin in deep carious lesions or in the presence of accessory canals on the root surface.

Acid Etching, Dental↗
PubMed1999

Thrombin activates the growth, cell-cycle kinetics, and clustering of human dental pulp cells.

Thrombin is activated during vascular injury and inflammation of the dental pulp. In the present study, we found that thrombin can stimulate the proliferation of pulp cells in a dose-dependent manner as analyzed by modified MTT assay. The cell number increased by 1.6, 1.77, and 2.14-fold over that of control after exposure to 5, 10, and 20 units/ml of thrombin for 5 days. Flow cytometry studies also found that thrombin (10 units/ml) can induce the cell cycle progression of pulp cells after 24 h of incubation, as revealed by increasing the proportion of cells in the S phase and the G2/M phase from 29 to 72%. Moreover, exposure to thrombin (> 5 units/ml) for 3 days led to marked clustering of pulp cells. We concluded that thrombin can regulate the growth, cell cycle progression, and functional reorganization of the pulp tissue during pulp healing and inflammatory processes.

Cell Aggregation↗
PubMed1999

Root deformation during root-end preparation.

Ultrasonic root-end preparation techniques have recently been introduced and revolutionized the field of endodontic surgery. However, several reports claimed that there was an increasing incidence of crack formation after ultrasonic root-end preparation. As yet, little work has focused on the root deformation during root-end preparation. Thus, the purpose of this investigation was to measure the amount of root deformation during root-end preparation with the use of microhandpiece and ultrasonic systems by using strain gauge methods, and simultaneously to detect any cracks with the aid of the stereomicroscope, stain, and an image processing system. The results demonstrated the ultrasonic instrumentation produced significantly greater strain on average than that generated with the microhandpiece system. From the viewpoint of fracture, any technique that could diminish the strain on the root would decrease the likelihood of fracture; however, no crack was observed on any resected surface of roots in this study.

Dental Instruments↗
PubMed1999

Adhesion receptor expression by hematopoietic cell lines and murine progenitors: modulation by cytokines and cell cycle status.

Hematopoietic progenitor cells are incubated with cytokine combinations for in vitro expansion of stem cells and to enhance retrovirus-mediated gene transfer. Optimization of the engraftment of these treated cells would be critical to the success of stem cell transplantation or gene therapy. Previous studies demonstrated that a 48-hour incubation of donor BALB/c bone marrow with a mixture of four cytokines (IL-3, IL-6, IL-11, and SCF), resulted in expansion of primitive progenitor/stem cells but a loss of long-term engraftment in nonmyeloablated or myeloablated recipients. We have established the expression pattern for a number of adhesion receptors by normal hematopoietic progenitors and cell lines and the modulation in expression induced by cytokines or cell cycle progression to ascertain the molecular basis for such defective engraftment. Northern blot analysis demonstrated that the cytokine combination of IL-3, IL-6, IL-11, and SCF dramatically down-regulated alpha 4 integrin receptor expression in HL-60 cells. Synchronized FDC-P1 cells exhibited modulation of alpha 4 expression through cell cycle progression, both by quantitative RT-PCR and flow cytometry. Normal murine bone marrow lineage-depleted, Sca+ cells expressed a number of adhesion receptors, including alpha L, alpha 1, alpha 3, alpha 4, alpha 5, alpha 6, beta 1, L-selectin, CD44, and PECAM as assessed by flow cytometry, immunofluorescence, and RT-PCR. There was modulation of the expression of several of these receptors after incubation in the four cytokines for 24 and/or 48 hours: the proportion of cells expressing alpha L, alpha 5, alpha 6, and PECAM increased, whereas the proportion of cells expressing alpha 4 and beta 1 decreased, after cytokine incubation. There was a demonstrable concomitant decline in adhesion of these cells to fibronectin after the cytokine incubation, a finding that correlates with the decrease in expression of alpha 4. These changes in adhesion receptor expression and function with cytokines and during cell cycle transit may be critical to stem cell homing and engraftment after transplantation, as multiple receptors could be involved in the process of rolling, attachment to endothelium, endothelial transmigration, and migration within the marrow space.

Animals↗
PubMed1999

Childbearing at older age and endometrial cancer risk (Sweden).

OBJECTIVES: Several studies have found an inverse association between older age at last birth and endometrial cancer risk. A nested case-control study was undertaken to examine the influence of this and other aspects of reproductive patterns on the risk of developing endometrial cancer. METHODS: Among women born in 1925 and later, 4,839 eligible patients were identified in the Swedish Cancer Register. For each case, five individually age-matched controls were randomly selected from a population-based Fertility Register. Relative risks were estimated from odds ratios obtained from conditional logistic regression analyses. RESULTS: Compared to uniparous women, childless women were at a higher risk of endometrial cancer (odds ratio [OR] = 1.38, 95% confidence interval [CI] = 1.25-1.52). This association was stronger in younger (< 50 years) than in older (50+ years) women. At all ages of first birth, a delivery was associated with a reduced risk of endometrial cancer that slowly diminished with time. Among parous women, the risk decreased by almost 20% for each additional live birth (OR = 0.81, CI = 0.78-0.84). In an analysis limited to women with two or more births that compared the independent effects of age at first and at last birth, only older age at last birth was associated with a lowered risk of endometrial cancer. The risk decreased at a rate of about 15% per five-year delay of last birth. CONCLUSIONS: Endometrial cancer is often referred to as the prototype hormonally-determined disease in women. However, our findings give further support to the hypothesis that a birth may not only affect risk through hormonal influences, but possibly also through mechanical shedding of cells that have undergone malignant transformation.

Adult↗
PubMed1999

Maternal pregnancy hormone levels in an area with a high incidence (Boston, USA) and in an area with a low incidence (Shanghai, China) of breast cancer.

Characteristics probably associated with the fetal hormonal milieu have recently been shown to increase (birth size indicators, prematurity, neonatal jaundice) or decrease (pregnancy toxaemia) breast cancer risk in the female offspring. However, it is unknown whether differences in pregnancy hormone levels may contribute to the marked geographical variation in breast cancer incidence. We have compared, in a highly standardized manner, pregnancy hormone levels in a population with high incidence and one with low incidence of breast cancer. Three hundred and four pregnant Caucasian women in Boston and 334 pregnant Chinese women in Shanghai were enrolled from March 1994 to October 1995. Levels of oestradiol, oestriol, prolactin, progesterone, human growth hormone, albumin and sex hormone-binding globulin were measured in maternal blood at weeks 16 and 27 of gestation and compared between the two study sites using non-parametric Wilcoxon's rank-sum test. Demographical, anthropometrical and pregnancy characteristics were ascertained through interview, and relevant variables concerning delivery and the newborn were abstracted from medical records and paediatric charts. During the first visit, median serum levels of all studied hormones were statistically significant, and in most instances substantially, higher among Chinese women, who have a low incidence of breast cancer, compared with American women, who have a high incidence of breast cancer. An analogous pattern was evident during the second visit, although the relative differences tended to be smaller. Further research is needed to identify lifestyle or other exogenous determinants of pregnancy hormone levels, as well as possible mechanisms by which they may influence carcinogenic processes in the breast and possibly other organs.

Adult↗
PubMed1999

Delivery of a severely anaemic fetus after partial molar pregnancy: clinical and ultrasonographic findings.

The incidence of a normal live fetus and a partial molar placenta is extremely rare. Although triploidy is the most frequent association, a fetus with normal karyotype can survive in cases of partial molar pregnancy. We report a case of partial molar placenta in which a live female baby was delivered at 32 weeks gestation by a 30-year-old woman. At the 18th week, ultrasonographic examination revealed a normal fetus with a huge, multicystic placenta. Chromosomal evaluation by amniocentesis revealed a normal female karyotype (46,XX), and serial biometric measurement of the fetus showed normal growth during pregnancy. There were no obstetric complications until the 32nd gestational week when preterm rupture of the membranes occurred. The electronic fetal heart beat tracing showed a repeated sinusoid pattern and late deceleration after admission. The patient underwent emergency Caesarean section and delivered a 1551-g, anaemic female baby with an Apgar score of 1, 4 and 6 at 1, 5 and 10 min, respectively. The baby recovered within 2 weeks after respiratory support and transfusion of packed red blood cells. Although anaemia is one of the risk factors that jeopardize the fetus in the case of partial molar pregnancy, termination is not indicated when the fetus is normal and no complications have occurred.

Adult↗
PubMed1999

Effects of areca nut, inflorescence piper betle extracts and arecoline on cytotoxicity, total and unscheduled DNA synthesis in cultured gingival keratinocytes.

Betel quid (BQ) chewing has a strong correlation with oral leukoplakia, submucous fibrosis and oral cancer. For elucidation of its pathogenesis, we investigated the effects of areca nut (AN) and inflorescence piper betle (IPB) extracts and arecoline on the growth, total DNA synthesis (TDS) and unscheduled DNA synthesis (UDS) of cultured human gingival keratinocytes (GK). Arecoline and AN extract suppressed the growth of GK over 5 days of incubation in a dose-dependent fashion. At concentrations of 100, 200 and 400 microg/ml, AN extract suppressed the growth of GK by 31%, 46% and 90%, respectively. The IPB extracts exerted less inhibitory effect on the growth of GK. IPB extract (200-400 microg/ml) decreased cell numbers by 20-40% over 5 days of incubation. Moreover, at a concentration of 0.1, 0.2 and 0.4 mM, arecoline suppressed cell growth by 44%, 77% and 96%, respectively. However, only AN extract induced TDS and UDS in cultured GK within 6 h of exposure. Induction of UDS by AN extract was concomitant with the presence of apparent intracellular vacuolization. Arecoline was also toxic to GK, but did not induce intracellular vacuolization. At a concentration range of 200-1600 microg/ml, AN extract induced TDS by 2.1- to 6.5-fold. Furthermore, at a concentration of 400-1600 microg/ml, AN extract elevated the UDS by 2.4- to 5.5-fold more than that of untreated control. On the contrary, IPB extract (200-1600 microg/ml) and arecoline (0.2-1.6 mM) inhibited the TDS and UDS of GK to a different extent. Simultaneous exposure of confluent GK to AN extract, IPB extract and arecoline for 1 to 5 days led to different degrees of cytotoxicity that was dose- and time-dependent. These results indicate that AN, IPB and arecoline take part in the pathogenesis of BQ chewing-related oral mucosal lesions, possibly through both genotoxic and non-genotoxic mechanisms.

Areca↗
PubMed1999

The effects of extracellular citric acid acidosis on the viability, cellular adhesion capacity and protein synthesis of cultured human gingival fibroblasts.

Root surface demineralization is widely used as an adjunct to periodontal treatment. To clarify the influence of citric acid root conditioning on periodontal wound healing, the effects of citric acid and associated extracellular acidosis on the viability (MTT assay), attachment and protein synthesis ([3H]-proline incorporation into trichloroacetic acid-precipitated proteins) of human gingival fibroblasts (GF) were investigated. A concentration of 47.6 mmol/L of citric acid (pH 2.3) in water led to total cell death within three minutes of incubation. Media containing 23.8 mmol/L and 47.6 mmol/L of citric acid exerted strong cytotoxicity (47 to 90 per cent of cell death) and inhibited protein synthesis (IC50 = 0.28 per cent) of GF within three hours of incubation. Incubation of cells in a medium containing 11.9 mmol/L of citric acid also suppressed the attachment and spreading of fibroblasts on culture plates and Type I collagen, with 58 per cent and 22 per cent of inhibition, respectively. Culture medium supplemented with 11.9, 23.8 and 47.6 mmol/L of citric acid also led to extracellular acidosis by decreasing the pH value from 7.5 to 6.3, 5.2 and 3.8, respectively. In addition, it was confirmed that the toxic effect of media containing citric acid was due to their acidity rather than the citrate content. Most of the citric acid-induced cell death could be prevented by adjusting the pH value of the culture medium to pH 7.5. Sodium citrate, at a concentration of 47.6 mmol/L, also exerted little cytotoxicity. The results suggested that toxicity of citric acid in specific stages of the healing process must be considered prior to its clinical application. Careful management of citric acid in order to avoid contact with tissue or the development of other demineralizing agents is important in enhancing periodontal wound healing.

Acidosis↗