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Biomedical subjects

M F Chen

Publications and source records attributed to M F Chen.

At least 397 records · Page 22Linked to original sources
PubMedDate not supplied

Reoperative thyroid surgery.

Reoperative thyroid surgery is an uncommon operation associated with a high complication rate. We retrospectively reviewed the data of 115 patients to study the incidence of complications after reoperative thyroid surgery. There were 107 women and 8 men (13.4:1.0) with an average age of 42.8 years (range 18-80 years). The most frequent indication for reoperation was completion thyroidectomy for a carcinoma identified by permanent sections (50 patients, 43.5%). Reoperative surgery was performed on 13 (11.3%) patients with recurrent thyroid cancer. The remaining 52 patients underwent reoperation for recurrent thyrotoxicosis (12 patients, 10.4%), recurrent nodular goiter (28 patients, 24.3%) or recurrent multinodular goiter (12 patients, 10.4%). Seven patients with recurrent nodular goiter and one patient with recurrent thyrotoxicosis underwent total thyroidectomy for the presence of malignancies that were identified by frozen sections. Overall, the interval between the initial and reoperative procedures ranged from 1 day to 33 years (2335 +/- 272 days). The length of hospital stay was 5.8 +/- 0.5 days. The length of time needed for reoperative thyroid surgery was 122.0 +/- 6.2 minutes. There was no 30-day perioperative mortality. The postoperative complications consisted of transient hypoparathyroidism in six patients (5.2%), permanent hypoparathyroidism in two patients (1.7%), transient RLN palsy in 3 patients (2.6%), and permanent recurrent laryngeal nerve palsy in two patients (1.7%). Reoperative thyroid surgery can be performed safely with little morbidity to the patient.

Adolescent↗
PubMedDate not supplied

Noradrenergic mediation of the memory-enhancing effect of corticotropin-releasing factor in the locus coeruleus of rats.

A role for the locus coeruleus (LC) in attention and behavioral arousal has been suggested. The present study examined the effect of corticotropin-releasing factor (CRF) in the LC on memory retention of a passive-avoidance task in rats. Our results indicate that intra-LC CRF injection significantly improved retention performance. Decreases of norepinephrine (NE) levels in the hippocampus and the amygdala occurred in these animals. Intra-hippocampal 6-hydroxydopamine pretreatment did not affect memory alone, while it antagonized the memory-enhancing effect of CRF in the LC. This finding suggests that the dorsal NE pathway is involved in the memory consolidation process. Similar to the effect of CRF, application of the alpha 2-adrenergic antagonist yohimbine to the LC also dose-dependently enhanced memory, suggesting that CRF improved memory through activation of NE neurons in the LC. Finally, the anxiolytic chlordiazepoxide, at a concentration that did not alter memory by itself, prevented the memory-facilitating effect of CRF in the LC. Our findings suggest that the LC is an important structure in modulating learning and memory processes of passive avoidance learning in rats. CRF may enhance memory through activation of NE neurons in the LC and, at least in part, through the dorsal NE pathway. Furthermore, the LC is probably an anatomical substrate for anxiety and intra-LC CRF may enhance memory through its anxiogenic actions.

Amygdala↗
PubMedDate not supplied

Intraoperative fiberoptic choledochoscopy for malignant biliary tract obstruction.

A prospective study to determine the safety and effectiveness of intraoperative fiberoptic choledochoscopy in the management of malignant obstruction of the biliary tree was conducted in 44 patients. There were 12 patients with cancer of the pancreatic head, 9 with adenocarcinoma of the distal common bile duct, 4 with adenocarcinoma of the ampulla of Vater, 8 with cholangiocarcinoma of the common hepatic duct, 9 with intrahepatic bile duct carcinoma, and 2 with hepatocellular carcinoma. Five patients with intrahepatic bile duct carcinoma and two with hepatocellular carcinoma were found during a search for intrahepatic duct stones in patients with recurrent cholangitis. In nine patients with bile duct carcinoma (seven extrahepatic and two intrahepatic), histopathological diagnosis was made at operative endoscopy. Treatment strategy was altered in seven patients based on findings at operative choledochoscopy. Complications were few with no mortality. Intraoperative fiberoptic choledochoscopy was safe and useful in the management of malignant obstruction of the biliary tree.

Adenocarcinoma↗
PubMedDate not supplied

Evaluation of placental morphology and growth factor receptors in women receiving antiepileptic drugs: a pilot study.

A direct teratogenic effect of antiepileptic drugs (AEDs) on the fetus has been postulated. However, there may also be a primary effect of AEDs on placenta, with secondary consequences to the fetus. Thirteen carefully medically controlled epileptic women were followed prenatally and perinatally. Placentas from all were investigated morphologically and in two with electronmicroscopy. In nine patients, the placentas were studied with respect to insulin and insulin-like growth factor (IGF-I and IGF-II) receptor activity. In this pilot study of a group of carefully medically controlled epileptic women with low levels of AEDs, the results did not differ from normal controls. The possibility of adverse effects of higher concentrations of AEDs cannot be excluded, however.

Adult↗
PubMedDate not supplied

Dobutamine stress echocardiography for detecting coronary artery disease.

To assess the value of dobutamine stress echocardiography (DSE) to detect coronary artery disease (CAD) and to compare the diagnostic accuracy between DSE and treadmill exercise test (TXT), 104 patients (mean age 58 +/- 12 years) presenting for coronary angiography were prospectively studied. TXT was performed according to the Bruce protocol. Dobutamine (5-40 micrograms/kg/min) was infused in 3-min stages. Digital echocardiograms were recorded on-line at baseline, during low- and peak-dose dobutamine infusion, and at recovery. An echocardiogram positive for CAD was defined as the one showing a new wall motion abnormality (WMA) induced by dobutamine. There were no major complications during the study. Significant CAD (> or = 50% diameter stenosis) was present in 17 of 30 patients who had normal echocardiograms at baseline. The sensitivity for detecting CAD was 76% by TXT and 94% by DSE, and the specificity was only 38% by TXT and 92% by DSE, respectively. Seventy-four patients had localized rest WMAs. Twenty-four had no significant CAD or lesions only confined to regions with abnormal rest wall motion, and 50 had disease remote from these regions. The sensitivity for detection of remote disease was 60% by TXT and 76% by DSE, and the specificity was 75% by TXT and 96% by DSE, respectively. In conclusion, DSE is a safe and accurate diagnostic tool for identifying CAD and for predicting the extent of disease in those who have localized rest WMAs.

Aged↗
PubMedDate not supplied

Successful treatment of acute myocardial infarction by thrombolytic therapy in a patient with primary antiphospholipid antibody syndrome.

A dilemma must be faced when deciding whether or not to use thrombolytic therapy in patients with acute myocardial infarction and circulating antiphospholipid antibody. This report is about a patient whose infarct-related coronary artery was successfully revascularized by recombinant tissue plasminogen activator without any major bleeding complications. The nature of the infarct-related artery was described by the use of intravascular ultrasonography.

Antiphospholipid Syndrome↗
PubMedDate not supplied

Role of transesophageal echocardiography in the management of metastatic tumors invading the left atrium.

Two patients with metastatic tumors invading the left atrium are described. One is a 52-year-old woman with osteosarcoma; the other is a 77-year-old man with lung cancer. The first patient presented with severe dyspnea 1 year after treatment for a primary tumor. Cardiac metastasis was suspected, then documented by transesophageal echocardiography. The study of pulmonary vein flow showed decreased systolic forward and increased diastolic components of pulmonary venous flow. The second patient presented with chronic cough without dyspnea. Although a huge tumor invaded the left atrium, as in the first patient, a normal pattern of pulmonary vein flow with higher systolic than diastolic velocities was shown by transesophageal echocardiography. Thus, transesophageal echocardiography is not only a useful tool to diagnose left atrial metastatic tumors, but also the study of pulmonary venous flow patterns can delineate causes of dyspnea in patients with metastatic tumors invading the left atrium.

Adenocarcinoma↗
PubMedDate not supplied

Dobutamine stress echocardiography compared with exercise thallium-201 single-photon emission computed tomography in detecting coronary artery disease-effect of exercise level on accuracy.

Dobutamine stress echocardiography (DSE) and exercise thallium-201 single-photon emission computed tomography (SPECT) were compared for the accuracy in detecting coronary artery disease (CAD) in 51 consecutive patients. Twenty-six (group 1) of the 51 patients achieved adequate exercise end points, and 25 (group 2) did not. There were 38 patients with angiographically documented CAD. The overall sensitivity of DSE and thallium-201 SPECT in detecting CAD was 92 and 76% (p = NS), and the specificity was 77 and 77% (p = NS), respectively. The sensitivity of DSE is the same as that of SPECT in group 1 (90 vs. 90%; p = NS) and higher than that of SPECT in group 2 (94 vs. 61%; p < 0.05). In patients with CAD without a history of acute myocardial infarction or pathological Q wave on resting electrocardiogram, the sensitivity of DSE is the same as that of SPECT in group 1 (82 vs. 82%; p = NS) and also higher than that of SPECT in group 2 (90 vs. 40%; p = 0.03). The sensitivity in detecting individual coronary artery lesions with DSE and thallium-201 SPECT was not affected by the exercise level. The agreement between DSE and thallium SPECT in detecting patients with CAD was 88% in group 1 (kappa = 0.69; p < 0.001) and 76% in group 2 (kappa = 0.45; p = 0.01). The agreement in detecting vascular territories with ischemia was 68% in group 1 (kappa = 0.30; p < 0.01) and 75% in group 2 (kappa = 0.33; p < 0.001). The agreement in detecting vascular territories with a scar was 87% in group 1 (kappa = 0.55; p < 0.001) and 85% in group 2 (kappa = 0.44; p < 0.001). In conclusion, the sensitivity and specificity of DSE in detecting CAD are similar to that of thallium-201 SPECT with an exercise level > or =85% of the maximal predicted heart rate. However, in patients who cannot exercise adequately, DSE is more accurate than thallium SPECT. The agreement between DSE and thallium SPECT in detecting patients with CAD and identifying ischemia of individual vascular territories is also affected by the exercise level.

Cardiotonic Agents↗
PubMedDate not supplied

Assessment of the functional significance of coronary artery stenosis by dobutamine-atropine stress echocardiography.

This study was performed to evaluate whether dobutamine stress echocardiography (DSE) can provide any additional information regarding the location and severity of coronary artery disease (CAD) in an individual patient. DSE was performed in 233 patients with clinical manifestations of angina pectoris. There were 162 patients with angiographically documented CAD defined as > or = 50% diameter stenosis. The severity of coronary lesions was divided into three groups: 50-75, 76-90 and >90%. The diagnostic sensitivity in detecting left anterior descending artery (LAD) and right coronary artery (RCA) lesions was higher for lesion severity of>90% than of 50-75% (p = 0.01 for LAD and p < 0.05 for RCA). The diagnostic sensitivity in detecting CAD was highest among patients with proximal coronary lesions (89% for LAD, 64% for the left circumflex artery, and 81 % for the RCA). When lesion severity increased from 50-75 to >90%, wall motion scores at peak dose during dobutamine infusion increased from 12.3 +/- 4.3 to 18.4 +/- 5.4 (p = 0.003) in the proximal LAD lesion group and from 10.6 +/- 2.0 to 20.4 +/- 5.9 (p < 0.0001) in the mid-distal LAD lesion group. When lesion severity increased from 50-75 to >90%, wall motion scores at peak dose increased from 5.9 +/- 2.0 to 8.0 +/- 2.5 (p < 0.05) in the proximal RCA lesion group and from 5.2 +/- 2.1 to 8.1 +/- 1.9 (p < 0.05) in the mid RCA lesion group. However, the change in wall motion scores did not reach statistical significance in proximal and distal lesions of the left circumflex artery when lesion severity increased from 50-75 to >90%. The correlation coefficient between quantitative wall motion score and Gensini's score was 0.54 (p = 0.0001) in all patients and 0.6 (p = 0.0001) in patients without myocardial infarction. In conlcusion, the functional significance of lesion severity and distribution can be evaluated by DSE. Regional dyssynergy of LAD and RCA territories during peak-dose dobutamine infusion was most apparent at the stenotic level >90%.

Atropine↗
PubMedDate not supplied

Simultaneous dobutamine stress echocardiography and thallium-201 perfusion imaging for the detection of coronary artery disease.

To compare the diagnostic value of dobutamine stress echocardiography with dobutamine thallium-201 single-photon-emission computed tomography (SPECT) in detecting coronary artery disease, we performed both tests simultaneously on 93 patients who also underwent coronary arteriography. Dobutamine was infused at rates of 5, 10, 20, 30 and 40 microns/kg/min in 3-min stages. The left ventricle was divided into anteroseptal, posterolateral and inferior regions. Within each region, wall motion or perfusion abnormalities were classified as normal, ischemia or fixed defect. The response to stress was concordantly classified by both tests in 67 patients (72%, kappa = 0.48). Regional agreement for abnormalities was observed in 79% (kappa = 0.56) of the 279 regions analyzed. Dobutamine echocardiography detected 62 (93%) and thallium SPECT 60 (90%, p = NS) of the 67 patients with significant coronary artery disease (> or = 50% diameter stenosis). The specificity was 77 (20 of 26) and 81% (21 of 26), respectively. The accuracy was 88 and 87%, respectively. Combined the two tests gave a sensitivity of 97%, a specificity of 65% and an accuracy of 88%. The accuracy for detecting individual coronary stenosis with echocardiography was 83% for the left anterior descending artery, 84% for the right coronary artery and 73% for the left circumflex artery. With SPECT, it was 83, 87 and and 76%, respectively. In conclusion, dobutamine stress echocardiography and thallium SPECT provide a comparable accuracy for detection and localization of coronary artery disease, and for identification of regional myocardial abnormalities. Performing the two tests simultaneous is feasible but it adds limited value in detecting coronary artery disease.

Adrenergic beta-Agonists↗
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Stability of the B vitamins in mixed parenteral nutrition solution.

The effects of various light conditions such as fluorescent light, and indirect and direct sunlight on the stability of the water-soluble B vitamins in parenteral mixtures were studied. The levels of the B vitamins were determined by microbiologic assays and spectrophotometrically. Most of the B vitamins were found to be stable. However, indirect and direct sunlight destroyed 47 and 100%, respectively, of riboflavin-5-phosphate in eight hours. Direct sunlight destroyed 86% of pyridoxine HCl. There was no loss of folic acid in parenteral nutrition mixtures after storage for 7 wk. The microbiologic assays were found to be reliable to measure the levels of the B vitamins in parenteral nutrition solution.

Bacteria↗
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The importance of a source of sufficient protein in postoperative hypocaloric partial parenteral nutrition support.

A comparison of postoperative metabolic and nutritional responses to different hypocaloric parenteral nutrition supports was performed in 42 patients with various gastric lesions. Sixteen patients (group A) received 3000 mL of a 5% glucose in water or glucose in saline infusion per day after surgery (approximately 10 kcal/kg per day). Another 14 patients (group B) received 2000 mL of 5% glucose in water or saline plus 1000 mL of 5% amino acid solution per day (approximately 10 kcal/kg per day and 1 g of protein per kilogram per day). The other 12 patients (group C) received 2000 mL of 5% glucose in water or saline plus 500 mL of 5% amino acid solution and 500 mL of 10% fat emulsion (approximately 20 kcal/kg per day and 0.5 g of protein per kilogram per day). After 7 days of study, all three groups were found to have a decrease in body weight, mid-arm circumference, triceps skin-fold, and serum albumin level, and the differences among them were not significant. Groups B and C had significantly less negative mean nitrogen balance than group A (-5.54 +/- 0.63 g/d and -6.07 +/- 0.49 g/d vs -9.20 +/- 0.68 g/d). Group B also had a significantly greater increase of transferrin (from 175.5 +/- 9.9 mg/dL to 185.4 +/- 9.3 mg/dL) than group A and a significantly greater increase in total lymphocyte count (from 956 +/- 113 cells/mm3 to 1196 +/- 176 cells/mm3) than groups A and C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Rhabdomyomatosis of newborn lung: a case report with immunohistochemical and electronmicroscopic characterization of striated muscle cells in the lung.

Interstitial proliferation of striated muscle cells in the lung is rare. A few cases in the literature only document infants with associated lung and other major organ anomalies incompatible with long-term survival. In this report we document a case of diffuse patchy interstitial proliferation of striated muscle cells in the left lung and confirm their nature by immunohistochemistry and electron microscopy. In particular, we show that these skeletal muscle cells express alpha-sarcomeric actin, but not alpha-smooth muscle actin, indicating an antigenetically well-developed striated muscle phenotype despite morphologically embryonal features.

Female↗
PubMedDate not supplied

Obstructive jaundice secondary to hepatocellular carcinoma rupture into the common bile duct: choledochoscopic findings.

BACKGROUND/AIMS: Hepatocellular carcinoma presenting as obstructive jaundice caused by floating tumor debris in the common bile duct is rare. We report choledochoscopic findings in this rare condition. METHODOLOGY: From January 1981 to December 1995, 28 patients received surgical treatment for obstructive jaundice secondary to hepatocellular carcinoma rupture into the common bile duct. Among them, intra-operative choledochoscopy was performed in 18 patients. RESULTS: Choledochoscopic findings revealed tumor thrombus and an intraluminal yellowish nodular mass in all patients, blood clots in the bile duct in 8 patients, and the appearance of acute erythematous cholangitis in 4 patients. Choledochoscopy revealed that the site of hepatoma rupture was from the right intrahepatic duct in 9 patients, from the left hepatic duct in 7 patients, and from the hepatic hilum in 2 patients. Choledochoscopically guided hepatic resection was performed in 4 patients. CONCLUSIONS: Intra-operative choledochoscopy reveals the characteristic finding of an intraluminal yellowish nodular mass in patients with malignant obstruction of the bile duct due to hepatocellular carcinoma. Hepatic resection with a free margin of the involved hepatic duct can be achieved by a choledochoscopically guided operation.

Adult↗
PubMedDate not supplied

The different manifestation and outcome between pancreatitis and pancreatic malignancy with left-sided portal hypertension.

Left-sided portal hypertension can be induced by isolated splenic venous obstruction due to various etiologies, such as chronic pancreatitis and pancreatic malignancy. The patients may present with bleeding isolated gastric varices and hypersplenism in addition to their pancreatic lesions. In the past 3 years, we have encountered 24 patients with left-sided portal hypertension. They were diagnosed with an abdominal echogram, CT or splenoportography. Twelve patients had histories of acute pancreatitis for a few months to years. Eleven of them were found to have isolated gastric varices. Six of them underwent operation due to hypersplenism or pseudocyst. The postoperative courses were smooth and the gastric varices subsided after splenectomy. The other 12 patients with left-sided portal hypertension were diagnosed as having pancreatic malignancy. Only two of them were found to have isolated gastric varices. Seven of them received operations and only two patients with their tumors located at the pancreatic body and tail could be resected. The other 5 patients were diagnosed with abdominal CT and high serum CA 19-9. We concluded that the patients with left-sided portal hypertension can be suspected by isolated gastric varices without liver cirrhosis. The diagnosis can be confirmed by abdominal CT or splenoportography. The incidence of isolated gastric varices are significantly lower in the patients with pancreatic malignancy than those with chronic pancreatitis. The gastric varices subsided after splenectomy. The prognosis of pancreatic malignancy is poor and most of them are inoperable.

Adenocarcinoma↗
PubMedDate not supplied

Gastroduodenal perforation in cancer patients.

BACKGROUND/AIMS: Patients with advanced or metastatic cancer have compromised nutritional, metabolic, and immune conditions. Little is known about gastroduodenal perforation in cancer patients. METHODOLOGY: Data of 11 cancer patients with gastroduodenal perforation were retrospectively reviewed. RESULTS: There were 2 females and 9 males with a mean (+/- s.e.) age of 56.7+/-4.7 years and a median of 55. The primary malignancies included lung cancers (3 cases), hepatocellular carcinomas (2 cases), squamous cell carcinomas of the tongue (2 cases), malignant lymphoma of the small bowel (1 case), adenocarcinoma of the pancreas (1 case), adenocarcinoma of the stomach (1 case), and acute lymphoblastic leukemia (1 case). The average duration of symptoms was 36.5+/-10.1 hours (median: 24 hours). Methods of surgical treatment included simple closure of the perforation (6 cases), truncal vagotomy and pyloroplasty (3 cases), pyloroplasty (1 case), and subtotal gastrectomy (1 case). Four patients (36.4%) had post-operative complications. The post-operative hospital mortality rate was 18.2%. One patient died of sepsis with gastrointestinal hemorrhage and 1 died of hepatic failure and respiratory failure. Pre-operative shock is the only significant factor in predicting operative mortality. CONCLUSIONS: Gastroduodenal perforation occurring in cancer patients without chemotherapy had favorable short-term operative results.

Adult↗
PubMedDate not supplied

Malignancy in choledochal cysts.

BACKGROUND/AIMS: Malignancy in choledochal cysts is a rare condition. This study presents our experience with this condition, with emphasis on the clinical presentation, management and outcome. METHODOLOGY: Subjects included 80 adults with choledochal cysts treated from January 1979 to December 1995. Of these patients, 8 were found to have malignancy in the cyst and formed the basis of this study. RESULTS: Four patients had synchronous and 4 had metachronous carcinoma lesions arising in the choledochal cyst. The clinical presentation was: biliary tract infection in 5 patients, gastric outlet obstruction in 2 and right upper quadrant pain and body weight loss in 1. Operations for bile duct malignancy included total excision in 2 patients, choledochotomy with T-tube drainage in 2 patients, gastrojejunostomy in 2 patients, percutaneous transhepatic biliary drainage and gastrojejunostomy in 1 patient and metastatic lymph node biopsy only in 1. One patient died due to septic shock within 30 days of the operation (operative mortality). Postoperative survival time ranged from 4-13 months with a mean of 6.2 months. CONCLUSIONS: The frequency of malignancy in the choledochal cysts was 10% in the present series. Malignancy in the choledochal cyst should be highly suspected in patients with cholangitis symptoms, body weight loss and anemia. Prognosis in this disease entity is poor.

Adolescent↗