[Marital status and life expectancy].
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Demography↗
Biomedical subjects
M C Chen
Publications and source records attributed to M C Chen.
Validation of electrolytic-liquid tilt sensors for human motion measurement.
The development of inexpensive, low-weight, no-invasive sensors that can be used to accurately measure human motion is important for the evaluation of biomechanical risk during a variety of industrial work activities. Electrolytic liquid tilt sensors that measure the angular position of an object relative to the gravitational force vector may provide a valuable means for assessing the postural demand of work tasks. For example, the biomechanical cost to the low back could be assessed during manual material handling activities, or the demand to the shoulders could be evaluated during overhead construction work. Tilt sensors were tested during static and dynamic activities, using isovelocity and isoacceleration dynamometers to move the sensor. The output voltage of the sensors was found to be linearly proportional to the angular deviation of the dynamometer within an 150 degree range (r > 0.99). During constant angular velocity and constant angular acceleration movements, the correlation between the output of the dynamometer and sensor was high and linearly dependent on angular position. Hence, the sensors are capable of accurate motion measurement during static and controlled dynamic movements. Because of the inertia of the liquid within the sensor, its output during sudden acceleration/deceleration may cause some artifact which requires more extensive investigation.
Biomechanical Phenomena↗
Mononuclear cells and cytokines stimulate gastrin release from canine antral cells in primary culture.
Patients with Helicobacter pylori-associated gastritis have an increased release of gastrin. The mechanisms by which H. pylori affects the endocrine cells are unclear. We have used primary cultures containing canine antral G cells to examine the effects of human blood mononuclear cells, purified monocytes and lymphocytes, recombinant cytokines, and NH4Cl on gastrin release. Mononuclear cells and purified monocytes in direct contact with G cells stimulated gastrin release dose dependently. Separating mononuclear cells from G cells by Transwell filters with 0.4-micron pore size still produced a significant increase of gastrin release. Three human recombinant cytokines, interferon-gamma, tumor necrosis factor-alpha, and interleukin-2, but not interleukin-6 and interleukin-1 beta, each produced dose-dependent increases of gastrin stimulation. NH4Cl did not stimulate gastrin release. We conclude that mononuclear cells and purified monocytes prepared from human blood, as well as several cytokines, stimulate gastrin release from antral G cells. These factors may play an important role in the pathogenesis of H. pylori-associated hypergastrinemia.
Animals↗
Partially unroofed coronary sinus and persistent left superior vena cava: intracardiac echocardiographic observation.
Unroofed coronary sinus, a rare congenital anomaly first described by Raghib and colleagues1 in 1965, is a result of an embryologic error involving imperfect or complete failure of development of the left atriovenous fold, which is manifested as a focal (fenestration or partial unroofing of the coronary sinus) or complete absence of the coronary sinus septum. Before the era of echocardiography, precise diagnosis of this anomaly was possible only during surgical procedure or at autopsy. Since the advent of the echocardiography, several studies have reported the usefulness of two-dimensional transthoracic and transesophageal echocardiography in the diagnosis of unroofed coronary sinus. We describe the intracardiac echocardiographic delineation of partially unroofed coronary sinus and persistent left superior vena cava in a patient with atrioventricular nodal reentrant tachycardia. Incidental finding of the dilated coronary sinus during radio frequency ablation of the tachycardia led to the diagnosis of this unusual anomaly.
Adult↗
Postoperative morbidity and mortality of pancreaticoduodenectomy for periampullary cancer.
OBJECTIVE: To find out factors that may influence the mortality after Whipple's operation, whether duct to mucosa anastomosis is better than classic "dunking" pancreaticojejunostomy and whether age over 70 is a contraindication for this procedure. DESIGN: Prospectively randomised study. SETTING: Teaching hospital, Taiwan, R.O.C. PATIENTS: 93 patients with periampullary cancer undergoing Whipple's operation were randomly divided into two groups. Forty-six with periampullary cancer underwent invaginating pancreaticojejunostomy, and 47 patients underwent duct to mucosa anastomosis for reconstruction. MAIN OUTCOME MEASURES: Mortality and morbidity were compared between two groups. RESULTS: The over all mortality was 8% (7/93). An albumin concentration of less than 30 g/L before operation and operative blood loss influenced the surgical mortality both in the univariate and multivariate analysis. Age over 70 years was not a factor. Patients with duct to mucosa anastomoses had a leak rate of 4% (2/47), morbidity of 21% (10/47) and mortality of 6% (3/47). Patients with an invaginated pancreaticojejunostomy had a leak rate of 15% (7/46), morbidity of 33% (15/46), and mortality of 9% (4/46). The need for total parenteral nutrition in the invaginated group (33%) was statistically greater than in the other group (11%) (p = 0.01). CONCLUSIONS: The morbidity and mortality of pancreaticoduodenectomy for periampullary cancer although slightly greater for patients over the age of 70 are acceptable. The factors that may influence the mortality are an albumin concentration of less then 30 g/L and the amount of blood lost during operation. The duct to mucosa anastomosis is a safe procedure, which has a lower leak rate and less need for total parenteral nutrition than pancreaticojejunostomy.
Adult↗
Prognostic factors of resectable intrahepatic cholangiocarcinoma.
Intrahepatic cholangiocarcinoma is a rare disease. The prognostic factors of resectable cholangiocarcinoma have not been previously reported. Nineteen patients (10M, 9F) with resectable cholangiocarcinoma were investigated to find factors that might influence prognosis. The cumulative survival rate was measured using the Kaplan-Meier method. The log-rank test was used to compare two survivals. Age, sex, tumor size, and positive tissue carcinoembryonic antigen were factors that had no influence on prognosis. Patients with a positive HLA-DR, a well-differentiated carcinoma, and a clear resective margin had better prognoses but were statistically undifferentiatable from the other patients. Patients with positive hilar lymph nodes had poor prognoses (P < 0.01), whereas patients with positive mucobilia had good prognoses (P < 0.05). Positive staining for HLA-DR on tumor cells was observed in nine of 19 cases of intrahepatic cholangiocarcinoma. The positive HLA-DR staining correlated with a better prognosis, but no significant difference was noted between the positive and negative HLA-DR staining group. A positive hilar lymph node was a grave sign, as almost all patients of positive lymph node died within 9 months after operation. Positive mucobilia was a good prognostic sign that correlated with the long-term survival.
Bile Duct Neoplasms↗
The membrane-bound and soluble forms of HLA-G bind identical sets of endogenous peptides but differ with respect to TAP association.
The class Ib antigen HLA-G is expressed as a membrane-bound protein like classical class Ia molecules (M.HLA-G) but, unlike typical class I, is also expressed as a soluble protein (S.HLA-G) with a unique C terminus. Our results show that, similar to classical class I proteins, the membrane-bound form of HLA-G associated with TAP, as evidenced by the ability to immunoprecipitate HLA-G class I heavy chain with TAP antisera. In contrast, the soluble G protein did not appear to associate with TAP in the same manner, since similar immunoprecipitation experiments failed to detect soluble G complex. A detailed analysis of peptides bound to the soluble and membrane HLA-G proteins expressed in the B lymphoblastoid cell line 721.221 showed that, like class Ia complexes, both HLA-G proteins consist of heavy and light chains complexed with nonameric peptides in a 1:1:1 ratio. The two proteins bind essentially the same set of peptides, which are derived from a variety of intracellular proteins and define a peptide motif for HLA-G. The peptides contain Leu at the C terminus and Pro or small hydrophobic amino acids in position 3 followed by Pro or Gly in position 4. The complexity of the bound peptides is lower than that found for some class Ia complexes, but is more similar to class Ia than to the limited repertoire of some murine class Ib molecules.
ATP-Binding Cassette Transporters↗
Enhancer-mediated role for polyomavirus middle T/small T in DNA replication.
A major role for polyomavirus middle T/small T antigens in viral DNA synthesis was uncovered by examining the replication of middle T/small T-deficient mutants (hr-t mutants). hr-t mutants in the A2 genetic background showed a 16- to 100-fold defect in genome accumulation relative to the wild type when infections were carried out in exponentially growing NIH 3T3 cells in medium supplemented with low levels of serum (< 2.0%). A proportional decrease in the level of viral early transcripts was also seen. The replication defect of the hr-t mutants was partially overcome in the presence of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate. The defect was also alleviated by a duplication encompassing the alpha core enhancer domain that contains binding sites for the transcriptional activators PEA1/AP-1 and PEA3/c-ets. Such a duplication is present in all naturally occurring hr-t mutants and absent in the A2 strain. The effects of 12-O-tetradecanoylphorbol-13-acetate and alpha core duplication were additive but did not fully complement the absence of middle T/small T. In mixed infection competition experiments with two hr-t mutants, a genome that carried an alpha core duplication had a replication advantage (up to 17-fold) over a genome without duplication. This result demonstrates that one effect of the duplication is exerted directly at the level of DNA replication. The advantage of the duplication-bearing genome was established during the earliest stages of replication and was not further amplified in later rounds of replication. In the presence of middle T/small T, both genomes replicated to high levels and the advantage of the duplication-bearing genome was eliminated. On the basis of these results, we propose that factors that bind the alpha core domain (presumably PEA1 and PEA3) are present in limiting amounts in exponentially growing NIH 3T3 cells and play a crucial role in polyomavirus DNA replication. We further suggest that middle T and/or small T stimulates viral DNA replication by activating these factors. The fact that all middle T-/small T-defective hr-t mutants have evolved to contain enhancer duplications that encompass the PEA1 and PEA3 binding sites in the alpha core domain and partially restore their replication defect (A. Amalfitano, M. C. Chen, and M. Fluck, unpublished data) provides an adequate explanation for the fact that the importance of the role of the middle T and/or small T function in DNA replication has not been recognized previously. Much evidence is available in support of separate elements of this model.(ABSTRACT TRUNCATED AT 400 WORDS)
3T3 Cells↗
Tracheolaryngectomy for papillary thyroid cancer.
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Carcinoma, Papillary↗
Atypical skeletal tuberculosis mimicking tumor metastases: report of a case.
Skeletal tuberculosis (TB) generally involves the spine and large joints. Involvement of most other bones has been reported, but tuberculosis of the pubic symphysis is relatively unusual. This paper reports an unusual case of multiple bone lesions in the right symphysis, left sacroiliac joint and left elbow. The radiologic appearance simulated widespread metastatic disease or chondrosarcoma, but the diagnosis of tuberculosis was proven by biopsy and culture. Eight months after starting antituberculous treatment, the patient experienced an improvement in pain and limping gait, and felt well. Radiography of the pelvis also showed improvement. It is proposed that antituberculous therapy in such cases should be maintained for at least 1 year.
Bone Neoplasms↗
MRI of meniscus and cruciate ligament tears correlated with arthroscopy.
Findings from magnetic resonance imaging (MRI) studies of 50 knees were retrospectively interpreted. The results were correlated with arthroscopic findings. Multiple pulse sequences were performed including sagittal double-echo, coronal T1-weighted and gradient echo, axial gradient echo or fat suppression imaging. Three-dimensional MRI was performed if there was a high suspicion of a tear of the anterior cruciate ligament. The individual positive predictive value, sensitivity, specificity and accuracy were calculated from the comparison between MRI and arthroscopic findings of the menisci, anterior cruciate ligament and posterior cruciate ligament. The following results were obtained: 1) Tears of the medial meniscus-positive predictive value, 72%; sensitivity, 87%; specificity, 86%; and accuracy, 86%. 2) Tears of the lateral meniscus-positive predictive value, 85%; sensitivity, 85%; specificity, 90%; and accuracy, 88%. 3) Tears of the anterior cruciate ligament-positive predictive value, 88%; sensitivity, 95%; specificity, 89%; and accuracy, 92%. 4) Tears of the posterior cruciate ligament-positive predictive value, 100%; sensitivity, 100%; specificity, 100%; and accuracy, 100%. It is concluded that MRI is a noninvasive and accurate method for detecting the internal derangement of the knee.
Adolescent↗
Atrial septal motion in effusive--constrictive pericarditis: transesophageal echocardiographic study and hemodynamic correlation.
Transesophageal echocardiography was performed in 7 patients with effusive-constrictive pericarditis to analyze atrial septal motion(ASM). In 3 patients, the ASM was found to be normal with atrial septum (AS) moving toward the right atrium from ventricular mid-systole to early-diastole and toward the left atrium from mid-diastole to early-systole. Respiration had little effect on the ASM. In 2 patients, a brisk inversion of ASM toward the left atrium at ventricular early-to-mid systole was noted during inspiration. In the other 2 patients, a sustained ASM toward the left atrium during ventricular systole was found. In 4 of these 7 patients, hemodynamic studies were performed simultaneously with the transesophageal echocardiography. The ASM reflected the pressure gradient between the left atrium (as measured by pulmonary arterial wedge pressure) and the right atrium. The augmented ASM toward the left atrium occurred as left atrial pressure decreased markedly during inspiration. In conclusion, the ASM in patients with effusive-constrictive pericarditis showed 3 patterns: normal, sustained systolic motion toward the left atrium and a brisk systolic displacement toward the left atrium during inspiration. The ASM reflects changes in the interatrial pressure gradient.
Adult↗
Spontaneous rupture of hepatobiliary cystadenoma: a case report.
Hepatobiliary cystadenoma is a rare hepatic neoplasm which has a high tendency to recur and has malignant potential. We review the literature and report a case of intrahepatic cystadenoma presenting with abdominal pain and ascites following spontaneous rupture. Complete excision of the tumor offers the best chance of cure and avoids recurrence, secondary infection or malignant change.
Adenoma, Bile Duct↗
Effects of prostaglandins on gastrin release from canine antral mucosal cells in primary culture.
Evidence in vivo indicates that endogenous and exogenous prostaglandins can alter gastrin secretion. We have used primary cultures containing canine antral G-cells to study the cellular actions of prostaglandins on gastrin secretion, comparing the effects of prostaglandin E2 (PGE2) and its synthetic analogue enprostil. Enprostil (10(-10)-10(-6) M) inhibited gastrin secretion in response to bombesin, carbachol, and forskolin, the latter a receptor-independent activator of adenylate cyclase. This inhibition by enprostil was reversed by treatment with pertussis toxin (200 ng/ml, 8 h). However, enprostil did not inhibit the postreceptor stimuli 8-bromoadenosine 3',5'-cyclic monophosphate (10(-3) M), calcium ionophore A-23187 (10(-7) M), or 4 beta-phorbol 12-myristate 13-acetate (10(-8) M). In contrast, whereas PGE2 inhibited forskolin-stimulated gastrin release, PGE2 did not inhibit the response to carbachol or bombesin in control cultures. However, in pertussis toxin-treated cultures, PGE2 inhibition was reversed and, in contrast, the responses to bombesin, carbachol, and possibly forskolin were augmented. Indomethacin at a dose of 10(-5) M did not alter basal or bombesin-stimulated gastrin secretion. However, the somatostatin antibody CURE-S6 enhanced the response to forskolin and enhanced inhibition by PGE2, suggesting that endogenous somatostatin produced an inhibitory tone in these cultures and excluding the possibility that PGE2 acted via release of endogenous somatostatin. Our data suggest that in cultured antral cells gastrin release is regulated by inhibitory and stimulatory prostaglandin mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenylate Cyclase Toxin↗
Apical acidification induces paracellular injury in canine gastric mucosal monolayers.
We used primary monolayer cultures of enzyme-dispersed canine oxyntic mucosal cells mounted in Ussing chambers to characterize the apical barrier to H+. [3H]mannitol flux (MF) and [14C]inulin flux (IF) were used as size probes for tight junctions. Apical H+ produced a three-phase effect. In phase 1, as the apical pH was decreased from 7 to about 2.5, resistance (R) increased, but short-circuit current (Isc) did not change. In phase 2, an increased paracellular permeability developed at pH below 2.5-1.7, evidenced by decreased R and increased MF but not IF. Size sieving and monolayer integrity were preserved, and this paracellular leak was either fully reversed or stabilized by apical neutralization, depending on the duration of the paracellular leak. In phase 3, after sustained exposure to an apical pH below approximately 2, transepithelial integrity was lost; R decreased to fluid R, and both MF and IF increased. Basolateral acidification below pH 5.5 produced rapid monolayer disruption. Low concentrations of cytochalasin D (CD) decreased R and increased MF but not IF; apical acidification to pH 4 after CD increased R and decreased the MF, indicating reduced paracellular permeability by apical H+. Apical amiloride did not alter Isc; however, after 48 h of treatment with hydrocortisone and insulin, an amiloride-sensitive Isc component became evident. Our data indicate that the increase in R observed with apical acidification reflects decreased paracellular permeability and that the earliest injury with apical acidification is a selective paracellular leak.
Animals↗
Prognostic factors for pyogenic abscess of the liver.
BACKGROUND: Percutaneous drainage and antibiotics for pyogenic abscess are well established therapeutic modalities. However, the mortality rate for hepatic abscess of liver remains high. STUDY DESIGN: Three hundred fifty-two cases of pyogenic hepatic abscesses were studied to evaluate prognostic factors. RESULTS: Using univariate analysis, the following factors were associated with a high mortality rate: patient age, gas-forming abscess, rupture of abscess, bilobe involvement, clinical sepsis, bilirubin (more than 2 mg per dL), blood urea nitrogen (more than 20 mg per dL), serum creatinine (more than 2 mg per dL), aspartate aminotransferase (more than 100 U per L), and albumin (less than 2.5 gm per dL). Using multivariate analysis, the following were independent significant factors in predicting mortality: patient age (more than 60 years), blood urea nitrogen (greater than 20 mg per dL), serum creatinine (greater than 2 mg per dL), total bilirubin (greater than 2 mg per dL), and albumin (less than 2.5 gm per dL). CONCLUSIONS: Systemic effects of hepatic abscess with sepsis and multiple organ failure were significant factors in predicting mortality. Local findings, such as rupture of the abscesses, multiple abscesses, and gas-forming abscesses, were not independent factors. Percutaneous drainage is always considered if the condition of the patient can not be improved with antibiotic therapy. Operative treatment is indicated if the patient is unresponsive to medical treatment and percutaneous drainage or if the patient has complications of biliary tract stone or rupture of the abscess.
Aged↗
Agenesis of the internal carotid artery associated with neurofibromatosis type II.
We report a case of agenesis of the internal carotid artery associated with neurofibromatosis type II. Common carotid arteriograms showed no visualization of the internal carotid artery. CT revealed absence of the corresponding carotid canal. MR documented absence of the internal carotid artery in the cavernous sinus.
Adolescent↗
Neurofibromatosis, acute myelomonocytic leukemia, and disseminated tuberculosis: an adult case report.
Leukemia associated with neurofibromatosis has been reported to be predominantly nonlymphocytic and limited to childhood; it is rare in adulthood. An adult case is reported; the patient had nonfamilial peripheral neurofibromatosis (NF) (von Recklinghausen's disease), contracted acute myelomonocytic leukemia and disseminated tuberculosis (TB). After a four-month periods of anti-TB medication that disease was much improved, but the leukemic picture was still progressing. Chemotherapy was not given. This case further illustrated an association between acute nonlymphocytic leukemia (ANLL) and neurofibromatosis type 1 (NF-1) in adulthood. An attempt was made also to explain the relationship between disseminated tuberculosis and, in this instance, hematological abnormalities.
Humans↗