Biomedical subjects

M F Chen

Publications and source records attributed to M F Chen.

At least 73 records · Page 4Linked to original sources

PubMed2000

A randomized crossover evaluation of antianginal efficacy and safety of nitrolingual-spray and nitroglycerin tablet form in coronary artery disease patients.

Twenty-eight coronary artery disease patients with more than 50% stenosis in at least one major coronary artery completed this randomized crossover clinical trial for the comparison of efficacy and safety of Nitrolingual-Spray and nitroglycerin (NTG) tablets. Exercise time was lengthened to 399.1 s (spray) or 408.5 s (tablets), compared to a baseline of 387.3 s. Ischemic burden decreased to about -4.0 mm with both forms, compared to -7.5 mm at baseline (ANOVA: p = 0.003). The ischemic time improved to 137.2 s (spray) or 152.9 s (tablets), compared to 253.4 s at baseline (ANOVA: p = 0. 005). Patients taking tablets experienced more episodes of hypotension and/or headache compared to patients taking the spray. Nitrolingual-Spray is as effective and safe as NTG tablets for the treatment of symptomatic coronary heart disease.

Administration, Inhalation↗

PubMed2000

A comparison of carbon dioxide monitoring and oxygenation between facemask and divided nasal cannula.

The divided nasal cannula is a device recently released in Australia that couples oxygen delivery and end-tidal carbon dioxide (PETCO2) monitoring. This study compares the accuracy of PETCO2 measurements by the divided nasal cannula and those measured by a modified facemask (as currently used in this institution), with arterial partial pressure of carbon dioxide (PaCO2). In this crossover study, 30 patients who had arterial lines as part of their routine monitoring were given oxygen via nasal cannula and facemask preoperatively. The PETCO2 was measured with each device and a simultaneous PaCO2 and PaO2 measured after equilibration. The results demonstrate a significant difference between the PETCO2 as measured by each technique. The divided nasal cannula more accurately reflects PaCO2 (mean arterial to end expired gradient of 5 mmHg) and provides a more representative trace when compared to a traditional facemask system. Both methods provided adequate oxygenation.

Capnography↗

PubMed2000

Combined heart transplantation and resection of dissecting aneurysm of ascending aorta and aortic arch: a case report.

A 21-year-old male patient had suffered from palpitation and exertional dyspnea since October, 1997. He was admitted to our hospital, and a series of examinations were performed. Chest computed tomography (CT) revealed marked dilatation of the ascending aorta (about 7.5 cm at the proximal portion) and aortic annulus, an intimal flap in the ascending aorta and aortic arch was also noted. Cardiac catheterization revealed the pulmonary capillary wedge pressure was 33 mmHg, pulmonary artery pressure was 47/38 mmHg with a mean of 35.4. The cardiac index was 1.01 l/min/m2. Poor left ventricular contractility was shown by a left ventricular ejection fraction (LVEF) of 13.8% and a right ventricular ejection fraction (RVEF) of 5.13% by a radionuclide angiogram (RNA) study. Under the diagnosis of dilated cardiomyopathy and dissecting aortic aneurysm of the ascending aorta and aortic arch, he was put on a waiting list for heart transplantation. On November 11, 1997 he received heart transplantation. Resection of the dissecting aneurysm of the ascending aorta and the aortic arch and replacement with a 26 mm Vascutek graft were performed first under deep hypothermia and retrograde cerebral perfusion. Then while he was rewarming up, heart implantation was performed. He was discharged 30 days after surgery and has been doing well since then. As far as we know, no literature regarding combined heart transplantation and resection of a dissecting aneurysm of the ascending aorta and aortic arch has been reported.

Adult↗

PubMed2000

Selective inhibition of inducible nitric oxide in ischemia-reperfusion of rat small intestine.

PURPOSE: We investigated the role of constitutive and inducible nitric oxide (NO) synthases in intestinal ischemia-reperfusion (I/R) injury by observing the alterations in hemodynamics and intestinal microcirculation in response to I/R in rats, with or without inhibitors of NO synthases. METHODS: Adult male Sprague-Dawley rats (n = 9/group) received a standard I/R procedure alone: I/R plus intravenous administration of aminoguanidine (an inhibitor of inducible NO synthase); I/R plus L-NAME (NG-nitro-L-arginine methyl ester, an inhibitor of constitutive and inducible NO synthase); IR + L-Arg (L-arginine, an NO precursor); or a sham operation plus the vehicle. The I/R procedure was performed by clamping the perfusion vessels of a segment of the terminal ileum, and medication was administered intravenously before and after intestinal ischemia. The intestinal perfusion and leukocyte-endothelial interactions were evaluated with in vivo microscopy and laser Doppler flowmetry. Surface expression of CD11b (an adhesion molecule) of circulating granulocytes was measured with flow cytometry. RESULTS: Intestinal I/R produced circulatory alterations, intestinal microcirculatory derangement, energy depletion, and lipid peroxidation. Aminoguanidine significantly attenuated the reperfusion-related depression of mean arterial pressure (MAP), the decrease in intestinal perfusion index, the decrease in tissue ATP preservation, the increase in tissue malondialdehyde (MDA) level, and the expression of CD11b of circulating granulocytes. Administration of L-NAME had only minor and transient effects on reperfusion-related changes of MAP, intestinal flux, numbers of adherent leukocytes, and CD11b expression, but had some protective effects on tissue MDA and adenosine triphosphate levels and flow velocity. L-Arg further decreased the MAP but did not affect reperfusion-related variables. CONCLUSIONS: Our results show that the selective inhibition of inducible NO synthase by aminoguanidine attenuates the hemodynamic and microcirculatory derangement that results from intestinal I/R.

Animals↗

PubMed2000

Gender differences in the patterns of coronary angiography and PTCA use in a university hospital in Taiwan.

BACKGROUND AND PURPOSE: Coronary artery angiography (CAG) and percutaneous transluminal coronary angioplasty (PTCA) are important procedures for the diagnosis and treatment of patients with coronary artery disease. However, long-term trends in the frequency of CAG and PTCA use and their relation to gender have not been clearly determined in the Asian population. The purpose of this study was to investigate gender differences in the patterns of CAG and PTCA use in a university hospital in Taiwan during the period of 1983 through 1996. METHODS: We studied the monthly data of all patients who underwent CAG or PTCA in a university hospital in Taipei from 1983 through 1996. A time series analysis was used to estimate gender differences in the patterns of CAG and PTCA use. RESULTS: The frequency of CAG and PTCA increased significantly during this period. Before 1990, only a small number of patients underwent PTCA. However, this number increased steadily after 1990. Men were more likely to undergo CAG and PTCA than women. A time series analysis with fitted models was used to create an integrated moving average model. For CAG, the value of the estimated intercept for men was 2.5 times greater than that for women. In the PTCA series, the value of the intercept in men was 4.4 times greater than that in women. The patterns of trend change showed greater increases in men than in women, and a greater increase in the PTCA than in the CAG series. By transfer function modeling and intervention analysis, we found that the effect of CAG on the frequency of PTCA in men was 1.8 times greater than its effect in women. The estimated influence of the use of a new catheterization room (added in 1993) was 2.8 times greater in men than in women. The fitted model correlated well with the observed values in the next 12 months for both genders. CONCLUSIONS: We concluded that women had fewer CAG and PTCA procedures than men, and the influence of CAG on the PTCA series was significantly higher in men than in women.

Angioplasty, Balloon, Coronary↗

PubMed2000

Malignant phyllodes tumor of the breast metastasizing to the pancreas: case report.

Phyllodes tumor of the breast, or cystosarcoma phyllodes, is an unusual breast tumor. It is usually considered a benign lesion but may have malignant potential. Only a small proportion of malignant phyllodes tumors will metastasize. A phyllodes tumor of the breast metastasizing to the pancreas is rare. This 39-year-old female patient initially presented to us with a 5 x 4 x 2 cm tumor of a right breast. After excision of the tumor, she received another wise excision for a local recurrence of the tumor. Three years had passed when she started having hematemesis and tarry stools intermittently over a period of about one month. Clinical evaluation disclosed a huge mass with an ulcerated and bloody base over the second portion of the duodenum. A pancreatoduodenectomy was then performed. During the postoperative recovery period, a rapidly enlarging tumor of the right breast was noted. She subsequently underwent a total mastectomy of the right breast. Both the duodenal tumor and the breast tumor were found to be malignant phyllodes tumors. The rarity of this kind of patient and presentation is discussed.

Adult↗

PubMed2000

Clinicopathologic factors influencing long-term survival after resection for hepatocellular carcinoma.

BACKGROUND: The purpose of this study is to investigate the clinicopathologic factors that influence a survival longer than 5 years with no recurrence in patients after resection for hepatocellular carcinoma (HCC). METHODS: Between January 1992 and December 1994, 64 patients with complete viral markers study underwent curative hepatic resection for HCC. Four patients who died of surgical morbidity (hospital mortality, 6.3%) were excluded from this study. Among the 60 patients who survived, 10 patients (16.7%) survived over 5 years without recurrence. The clinicopathologic features and surgical procedures of the patients with long-term survival (> or = 5 years) without recurrence (n = 10) were compared with those of less than 5 years survival or with tumor recurrence (n = 50). The median follow-up was 64.8 months, ranging from 61.1 to 76.7 months. RESULTS: Six of the 10 patients were men with an age ranging from 35 to 75 years (mean, 57.6 +/- 9.7). Using univariate analysis, long-term survival without recurrence was significantly associated with a lower amount of perioperative blood transfusion (less than 7 units, p = 0.036) and an existence of tumor capsule (p = 0.031). But in multivariate analysis, only the presence of tumor capsule was statistically significant. CONCLUSIONS: Long-term survival without recurrence was related to a lower amount of perioperative blood transfusion, and an existence of tumor capsule in univariate analysis. But in multivariate analysis, only the existence of tumor capsule plays a significant role.

Adult↗

PubMed2000

Biliary hamartomas associated with biliary stones presenting as multiple microabscesses: case report.

A 63-year-old men suffered from fever, jaundice, and right upper quadrant pain for 1 week. Biliary stones with biliary tract infection were diagnosed. He was treated with parenteral antibiotics. However, abdominal ultrasonography showed multiple hyperechoic lesions in both lobes, and infiltrating hepatocellular carcinoma was suspected initially. Numerous hypervascular nodular-enhancing lesions were revealed by computed tomography. Magnetic resonance imaging further disclosed numerous tiny cystic lesions with peripheral enhancement. Exploratory laparotomy was performed for biliary calculi and probable underlying malignancy. Cholecystectomy, choledocholithotomy, and liver wedge biopsy were done. The pathology revealed bile duct hamartomas with microabscess formation. The past literature about biliary hamartomas is reviewed.

Abscess↗

PubMed2000

Surgery for adult polycystic liver disease.

Adult polycystic liver disease, commonly associated with polycystic kidney disease, can result in massive hepatomegaly and debilitating symptoms. Surgical intervention for symptomatic polycystic liver disease, such as cyst fenestration or liver resection has been associated with significant morbidity and inconsistent long-term palliation. However, selected patients with severe symptoms benefit from liver resection and extensive fenestration with acceptable morbidity and mortality. Total hepatectomy and orthotopic liver transplantation may be considered for patients with severe adult polycystic liver disease.

Adult↗

PubMed1999

Role of phosphorylation and physiological state in the regulation of the muscular chloride channel ClC-1: a voltage-clamp study on isolated M. interosseus fibers.

Chloride currents (I(Cl)) were investigated with the two-electrode voltage-clamp technique in enzymatically isolated fibers from interosseus muscles of wild-type (WT), denervated WT, and myotonic (ADR, ClC-1-deficient) mice. Characteristics of I(Cl) were consistent with previous observations on rat muscle fibers and cultured nonmuscle cells transfected with hClC-1 cDNA. In the presence of 0.1 mM anthracene-9-carboxylic acid and in ADR fibers, I(Cl) was reduced by >90%. WT interosseus fibers denervated 6-7 days prior to isolation showed approximately 50% I(Cl) compared to control fibers. Addition of 3.3 microM staurosporine, a nonspecific inhibitor of protein kinases, increased I(Cl) in WT interosseus fibers by a factor of approximately two and altered its kinetic characteristics. We conclude that in dissociated fibers cultured for 1-2 days, in contrast to freshly isolated muscles, chloride conductance is downregulated by a mechanism involving protein phosphorylation. In situ, this short-term regulation may complement transcriptional long-term regulation of ClC-1.

Animals↗

PubMed1999

Significance of dobutamine-induced ST-segment evaluation and T-wave pseudonormalization in patients with Q-wave myocardial infarction: simultaneous evaluation by dobutamine stress echocardiography and thallium-201 SPECT.

The clinical significance of stress-induced ST-segment elevation and T-wave pseudonormalization in infarct-related leads is still controversial. Therefore, we conducted the present study to assess this issue using simultaneous dobutamine stress echocardiography (DSE) and thallium-201 single-photon emission computed tomography. A total of 119 patients with Q-wave myocardial infarction were enrolled in this study. There were 58 patients with (group I) and 61 patients without (group II) dobutamine-induced ST-T changes. Left ventricular ejection fraction was 43 +/- 13% in group I and 49 +/- 14% in group II (p <0.05). The baseline, low-, and peak-dose global wall motion scores were similar between these 2 groups (26.2 +/- 6.1 vs 26.2 +/- 6.3 [p = NS]; 24.1 +/- 5.3 vs 23.5 +/- 5.7 [p = NS]; 26.4 +/- 5.7 vs 26.7 +/- 6.1 [p = NS]). The sensitivity, specificity, and accuracy of these ST-T changes for detecting residual myocardial viability and ischemia documented by DSE in all patients were 50%, 53%, and 51% (for viability), and 47%, 48%, and 47% (for ischemia), respectively. The sensitivity, specificity, and accuracy of these ST-T changes for detecting a reversible perfusion defect documented by thallium-201 single-photon emission computed tomography were 51%, 54%, and 52%, respectively. In conclusion, dobutamine-induced ST elevation and/or T-wave pseudonormalization is associated with poor resting left ventricular function. These ST-T changes are not associated with residual myocardial ischemia and viability in the infarct area. Therefore, these electrocardiographic changes alone cannot be reliably considered as distinctive markers in formulating the therapeutic strategy of coronary intervention.

Cardiotonic Agents↗

PubMed1999

Alzheimer's disease may not be a spirochetosis.

It has been reported previously that spirochetes could be one of the causes of Alzheimer's disease (AD). In this study, we have attempted to reproduce these findings by examining fresh blood samples from 22 patients diagnosed with early stage (n = 16) and late stage (n = 6) AD. The patients were participants in a clinical drug trial. Fresh necropsy brain cortical specimens from AD patients (n = 7) were also examined. Spirochetes were observed microscopically in the blood of only one late-stage AD patient. None of the brain tissues showed the presence of spirochetes. Our results suggest that spirochetes are probably not associated with AD.

Aged↗

PubMed1999

Somatostatin and octreotide modulate the function of Kupffer cells in liver cirrhosis.

In our previous studies we have shown that somatostatin and octreotide modulate the function of peritoneal macrophages and Kupffer cells in noncirrhotic livers. However, the effects of somatostatin on the Kupffer cells in cirrhotic livers are not known. In the present study, Kupffer cells, obtained from male rats with carbon tetrachloride-induced cirrhotic livers, were treated in vitro with somatostatin or octreotide and their effects on the release of nitric oxide, tumor necrosis factor-alpha (TNF-alpha) and peroxide (H2O2) determined. At concentrations of 10(-13) or 10(-10) to 10(-6) M of somatostatin or 10(-12) to 10(-10) M, or 10(-6) M of octreotide, the amount of nitric oxide released by Kupffer cells was significantly suppressed relative to that of untreated cells. Kupffer cells treated with less than 10(-12) M or greater than 10(-12) M of somatostatin or octreotide released less TNF-alpha compared to the untreated controls. In addition, zymosan-induced H2O2 release by Kupffer cells treated with 10(-9) to 10(-7) M somatostatin or with 10(-15) to 10(-13) M and 10(-9) to 10(-7) M of octreotide was greater than that of the untreated controls. These findings demonstrate that somatostatin and octreotide modulate the release of nitric oxide, TNF-alpha and H2O2 by Kupffer cells in cirrhotic livers depending on the concentrations of hormones used.

Animals↗

PubMed1999

Thyroid cancer with concurrent hyperthyroidism.

OBJECTIVE: To study the clinical manifestation, outcome, and factors predicting metastases in patients with thyroid cancer and concurrent hyperthyroidism. DESIGN: Retrospective study of 37 thyrotoxic patients with differentiated carcinomas of the thyroid who were operated on between 1979 and 1995. The follow-up period ranged from 562 days to 14 years 9 months (mean +/- SE, 2093+/-201 days). SETTING: University hospital with an annual performance rate of about 700 thyroid operations. PATIENTS: Thyroidectomy was performed in 37 patients (31 women and 6 men), including 33 papillary carcinomas and 4 follicular carcinomas. The mean +/- SE age of the patients was 38.6+/-2.2 years. RESULTS: The mean +/- SE diameter of tumors was 13.2+/-0.9 mm (range, 2-67 mm). The tumor size in 25 patients (68%) was 10 mm or smaller. Subtotal thyroidectomy (21 patients), total thyroidectomy (8 patients), near-total thyroidectomy (4 patients), and completion thyroidectomy (4 patients) were performed. Twenty-eight patients underwent postoperative sodium iodide I 131 (131I) ablation for thyroid remnant. There was 1 local recurrence, 3 metastases to regional neck lymph nodes, and 3 distant metastases. A patient with follicular carcinoma died of metastases at 3 years 4 months after thyroidectomy. Age, sex, duration of thyrotoxic symptoms, tumor size, histopathological findings, type of goiter, extent of surgery, 131I ablation, and 6-week postoperative serum concentrations of thyroglobulin or thyrotropin were not significant factors in predicting metastases. Serum levels of triiodothyronine and thyroxine before antithyroid treatment in the patients with metastases were significantly higher than in those without metastases. CONCLUSION: The majority of patients with thyroid cancer and concurrent hyperthyroidism have small carcinomas.

Adult↗

PubMed1999

Metaplastic carcinomas of the breast.

BACKGROUND AND OBJECTIVES: Metaplastic carcinomas of the breast are rare neoplasms. The purpose of the present study is to better characterize the clinical course, treatment, and prognostic factors of metaplastic breast carcinomas. METHODS: Data of 14 patients with metaplastic breast carcinoma were retrospectively reviewed. The follow-up period ranged from 2 months to 10 years, 10 months (median 4.3 years). RESULTS: The patients' ages ranged from 38 to 66 years (median 50.5 years). The tumors were 2.5 to 18 cm (median 4.8 cm) in size. Seven patients had axillary nodal metastases at the time of diagnosis. Estrogen and progesterone receptors were positive in only one tumor. Twelve patients underwent modified radical mastectomy and two patients underwent incisional biopsy. Adjuvant chemotherapy was administered to six patients, and radiotherapy to two patients after mastectomy. Two patients received preoperative chemotherapy. Seven patients were living without evidence of disease at a median of 7.3 years after surgery. A patient died of ovarian carcinoma without recurrence or metastasis of breast cancer. Metastases occurred in five patients at 4 to 16 months (median 8 months) after initial treatment. Duration of symptoms, TNM stage, tumor size, and axillary nodal status were significant prognostic factors of survival. CONCLUSIONS: The patients with metaplastic breast carcinomas may have a favorable prognosis.

Adult↗

PubMed1999

Telomerase activity is a useful marker to distinguish malignant pancreatic cystic tumors from benign neoplasms and pseudocysts.

BACKGROUND: Pancreatic serous cystadenoma, mucinous cystic neoplasms, ductal adenocarcinoma with cystic change, and pseudocysts are a spectrum of pancreatic cystic lesions. Their management strategy and prognosis are extremely diverse. Imaging study, cytology, and analysis of the tumor markers of cyst fluid are not always reliable in differentiation of these disease entities. MATERIALS AND METHODS: Fifteen patients with pancreatic cystic neoplasms (including six mucinous cystadenocarcinomas, two mucinous cystic neoplasms with borderline malignancy, two mucinous cystadenomas, and five serous cystadenomas), 4 patients with pancreatic ductal adenocarcinomas with cystic change, and 10 patients with pseudocysts were studied. Echo-guided or computed tomography-guided biopsies of pancreatic cystic lesions and their normal counterparts were conducted on all patients prior to operation or other management. The specimens were assayed for telomerase activity by using TRAP (telomere repeat amplification protocol). The level of telomerase activity in each specimen was semiquantitated as strong, moderate, weak, and none. The final diagnoses were made from histopathological examination of surgically resected or biopsied specimens. The efficacy of telomerase activity as a tumor marker to predict malignancy of pancreatic cystic lesions was evaluated. RESULTS: Three of the four pancreatic ductal adenocarcinomas with cystic change had strong or moderate telomerase activity; four of the six mucinous cystadenocarcinomas had moderate or weak telomerase activity; one of the two mucinous cystadenomas with borderline malignancy had weak telomerase activity; and none of their normal counterparts had detectable telomerase activity. In contrast, none of the two mucinous cystadenomas, five serous cystadenomas, and 10 pseudocysts had detectable telomerase activity. Based on these results, the sensitivity of telomerase activity for prediction of malignancy or premalignancy of pancreatic cystic lesions was 67%, the specificity was 100%, and the positive and negative predictive values were 1.0 and 0.81, respectively. The overall accuracy was 86%. CONCLUSIONS: The differential expressions of telomerase activity have been detected specifically in malignant and premalignant pancreatic cystic tumors, but not in benign cystic neoplasms or pseudocysts. The implications of these results are that telomerase activation takes part in the malignant transformation of pancreatic cystic neoplasms and that telomerase activity is a useful marker to distinguish malignant pancreatic cystic tumors from benign neoplasms and pseudocysts.

Adult↗

PubMed1999

Intrahepatic cholangiocarcinoma in Taiwan.

We report our experience of the surgical treatment of intrahepatic cholangiocarcinoma (ICC) in Taiwanese patients. A total of 162 patients with histologically proven ICC were treated of whom 106 (65. 4%) had associated hepatolithiasis. Patients with hepatolithiasis were in earlier stages than those without hepatolithiasis. Two-thirds of the patients with hepatolithiasis presented with acute cholangitis, and two-thirds of those without hepatolithiasis presented with hepatomegaly. The rate of hepatic resection was 29.6% (48 of 162), and these rates were 31.1% and 26.8% for the patients with and without hepatolithiasis, respectively. Ninety-three percent of the patients with hepatolithiasis underwent common bile duct exploration, compared with 18% of those without hepatolithiasis. The surgical mortality rates were 3.7% (6/162), for all patients, and 3. 8% and 3.6% for patients with and without hepatolithiasis, respectively. The morbidity rate was much higher in the patients with hepatolithiasis (37.7% vs 16.1%). The 1-, 3-, and 5-year survival rates were 35.5%, 20.5%, and 16.5% in the patients with hepatolithiasis and 27.2%, 8.8%, and 7.8% in those without hepatolithiasis. Concomitant hepatolithiasis prevented precise diagnosis preoperatively and precipitated biliary sepsis, which affected resectability and increased postoperative morbidity. Hepatolithiasis per se did not influence long-term survival.

Adult↗

PubMed1999

Carcinogenesis in the biliary system associated with APDJ.

Anomalous pancreaticobiliary ductal junction (APDJ) is a rare congenital anomaly which is considered to be an etiological factor in the development of carcinoma of the biliary tract. It is generally accepted that pancreatic juice reflux into the biliary tract due to APDJ is one of the etiologies of biliary tract cancers. Refluxing pancreatic juice results in changes of bile and induces chronic inflammation and increased cellular proliferation, leading to epithelial hyperplasia, metaplasia, and carcinoma of the biliary tract. K-ras mutations are more prevalent in the carcinomas of biliary tract associated with APDJ compared with those without APDJ. There is no difference in the overexpression of p53 between biliary tract carcinomas associated with APDJ and those unassociated with APDJ. Further studies are needed to evaluate the role of cytokines and growth factors in carcinogenesis of the biliary system associated with APDJ.

Adenocarcinoma↗