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Biomedical subjects

M F Chen

Publications and source records attributed to M F Chen.

At least 235 records · Page 13Linked to original sources
PubMed1994

Effects of estrogen on cardiovascular responses of premenopausal monkeys.

Exogenous estrogen administration has been shown to reduce the risk of coronary heart disease in women. However, there are limited data in regard to the effects of estrogen on cardiovascular function and hemodynamics. This experiment sought to determine the effect of exogenous estrogen administration on systemic hemodynamic variables and cardiovascular responses to adrenergic and vasodilator agonists in premenopausal cynomolgus monkeys. Adult female monkeys were given weekly i.m. injections of 1) saline (control, n = 6), 2) estradiol cypionate (100 micrograms/kg, n = 6) or 3) estradiol cypionate (700 micrograms/kg, n = 5) for 6 weeks. A Swan-Ganz thermodilution catheter and arterial catheters were used to measure cardiovascular hemodynamic parameters in anesthetized monkeys before and during i.v. infusion of 1, 2, 4 and 8 micrograms kg-1 min-1 of isoproterenol, phenylephrine and nitroprusside. The high-dose estradiol group had a higher cardiac output index (0.6 +/- 0.1 versus 0.25 +/- 0.1 liter min-1 kg-1, mean +/- S.E.M.) and lower systemic vascular resistance index (628 +/- 160 versus 2630 +/- 872 dyne x cm-5 x sec-2 kg-1) than the control group at base line before infusion of agonists (P < .05). High-dose estradiol administration attenuated the mean arterial blood pressure, cardiac output and systemic vascular resistance changes in response to infusions of phenylephrine, isoproterenol and nitroprusside (P < .05 versus control). It was concluded that the administration of high-dose estradiol resulted in systemic arterial dilation, although changes in hemodynamic variables (systemic vascular resistance and cardiac output) were attenuated during adrenergic stimulation and vasodilation.

Animals↗
PubMed1994

[Pharmacokinetics of matrine in healthy volunteers].

A sensitive high performance liquid chromatographic analytical method was established for determining the concentration of matrine in human serum. The recovery of matrine was 99.1-102.2%. The RSD (%) in within-day and between-days were no more than 6%. The calibration curve was linear in the range from 1.25 micrograms.ml-1 to 40.0 micrograms.ml-1 with r = 0.9997. The serum drug concentration-time curve after iv infusion with a dose of 6 mg.kg-1 in 100 ml glucose solution for 8 healthy volunteers was fitted to a 2-compartment open model. The excretion of unchanged drug in urine was 52.75% of the dose in 32 h and the ClR was 143.79 ml.min-1.

Adult↗
PubMed1994

Subcutaneous radionuclide venography. An effective method for diagnosis of deep venous thrombosis.

Traditional acupuncture points K-3 are physiologically tender points located halfway between the Achilles tendon and the medial malleolus. Recently, the authors developed a new method of radionuclide venography of the lower limbs, namely subcutaneous radionuclide venography (SC-RNV), by subcutaneous injection of Tc-99m pertechnetate at these points. The authors applied this method in a patient with suspected deep vein thrombosis of both lower limbs. For comparison, ascending radionuclide venography by intravenous injection (IV-RNV) of Tc-99m MAA and color Doppler ultrasound were also done. The SC-RNV showed partial obstruction of right popliteal vein and complete obstruction of the left popliteal vein with prominent collateral flows. These results were compatible with the findings of color Doppler ultrasound. However, the IV-RNV showed small narrowing with patency of the left popliteal vein, and normal flow on the right. This suggests that the results of SC-RNV may be different from that of IV-RNV. The benefits of SC-RNV in the detection of deep vein thrombosis are described.

Acupuncture Points↗
PubMed1994

The regeneration of cirrhotic liver after partial hepatectomy: a study using the rat carbon tetrachloride-induced cirrhotic model.

There are conflicting data regarding the ability of the liver to regenerate after partial hepatectomy in animals and humans with cirrhosis. The purpose of this study was to document liver regeneration after partial hepatectomy in a carbon tetrachloride rat model of cirrhosis. Liver cirrhosis was produced by weekly intragastric gavage with carbon tetrachloride in 80 adult male rats. Vehicle-gavaged rats (n = 24) served as healthy controls. Liver regeneration was documented 1, 2, 3 and 7 days after partial hepatectomy on the basis of restitution of liver mass and [3H] thymidine incorporation into liver DNA. Restitution of liver mass after partial hepatectomy was significantly decreased in carbon tetrachloride-treated rats at 1 and 7 days compared with the vehicle-treated control rats. In cirrhotic rats, restitution of liver mass at 1, 2, 3 and 7 days did not differ between 33% and 70% hepatectomy. Hepatic DNA synthesis, however, was significantly impaired at 1 and 2 days in cirrhotic rats after 70% hepatectomy and also at 1 day after 33% hepatectomy compared with non-cirrhotic rats. The results of this study indicated that live regeneration did occur after partial hepatectomy in carbon tetrachloride-treated rats but was impaired in comparison with that in vehicle-treated control rats.

Animals↗
PubMed1994

[Percutaneous transhepatic cholangioscopic lithotomy for hepatolithiasis--long-term results].

Thirty-eight cases of hepatolithiasis were treated by percutaneous transhepatic cholangioscopy (PTCS) from Oct. 1983 to Sept. 1987 at the Chang Gung Memorial Hospital. There were 20 males and 18 females, age distribution ranged from 18 to 85, with a mean of 44 year old. Those with a history of previous biliary operation for biliary calculi were the majority, representing 92.1% (35 cases) of patients. The location of the stones in 38 cases were: bilateral IHD in 11, right IHD in 14, left IHD in 13. Hepatolithiasis associated with intrahepatic duct or biliary-enteric anastomotic strictures occurred in 84.2% (32 cases). Those strictures were dilated by PTCS drainage catheter in 14 cases and by Gruntzig balloon catheter in 7 cases. Complete removal of hepatolithiasis by PTCS in 32 cases resulted in a success rate of 84.2%. The sessions of PTCS ranged from 1 to 18, or a mean of 5. Two cases had major complications during the course of PTBD and required a change to a PTCS catheter; one case had subphrenic hematoma which needed laparotomy, and another case had hemobilia with sepsis which resulted in mortality. Long-term follow-up results in 32 cases of successful PTCS in hepatolithiasis with a range from 3 to 7 years period were free of symptoms and without evidence of recurrent stones in 50% (16/32), free of symptoms with recurrent stones in 2 cases. Recurrent stones with cholangitis occurred in 10 cases and 2 cases had symptoms of cholangitis without evidence of recurrent stones.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Changes of alpha 1-adrenergic receptors in human liver during intraabdominal sepsis.

We studied changes in alpha 1-adrenergic receptors in human liver plasma membranes during intraabdominal sepsis using [3H]prazosin as a radioligand. Human liver tissues were obtained from nonseptic patients undergoing elective abdominal surgery (control group) and from patients with sepsis requiring laparotomy as a therapeutic measure (septic group). Septic patients were further divided into three subgroups on the basis of septic severity scores: mild sepsis (< 21), moderate sepsis (22 to 32) and severe sepsis (> 33). Plasma membranes were prepared by means of sucrose gradient centrifugation and were purified fivefold on the basis of the enrichment of the activity of the marker enzyme, 5'-nucleotidase. [3H]prazosin-binding studies show that the maximal binding capacity was increased by 49.6% (p < 0.01) in mild sepsis, relatively unchanged in moderate sepsis and decreased by 33.4% (p < 0.05) in severe sepsis (in femtomoles per milligram: 193.7 +/- 5.7 for control [n = 6], 289.8 +/- 23.4 for mild sepsis [n = 4], 192.3 +/- 16.3 for moderate sepsis (n = 4), 129.1 +/- 18.3 for severe sepsis [n = 5]). We found a significant inverse correlation (r = 0.85, p < 0.01) between changes in the densities of alpha 1-adrenergic receptors and septic severity scores. These data indicate that alpha 1-adrenergic receptors in human liver plasma membranes undergo dynamic changes during the development of sepsis--that is, the receptor number increased in mild sepsis, returned to a normal level in moderate sepsis and finally decreased in severe sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)

5'-Nucleotidase↗
PubMed1994

The incidence of diarrhea in patients with hypoalbuminemia due to acute or chronic malnutrition during enteral feeding.

OBJECTIVES: Critically ill patients usually have hypoalbuminemia. The incidence of diarrhea in patients with hypoalbuminemia receiving enteral nutrition was studied. METHODS: One hundred and ninety-eight patients with serum albumin level below 3 g/dl in the Burn Unit and Nutritional Support Service were retrospectively studied. Diarrhea was defined as liquid or loose stool at least three times a day with a daily volume of more than 300 g for at least 2 days. Most patients in the Burn Unit had acute or subacute onset of hypoalbuminemia, and most patients who were referred to the Nutritional Support Service had a chronic onset of hypoalbuminemia. The patients whose diarrhea were due to formula-related factors, administration techniques, or concomitant drug therapy were excluded. RESULTS: The results showed that 27% of the patients with albumin levels less than 2 g/dl had diarrhea, but only 10.5% of patients with albumin levels higher than 2 g/dl had diarrhea; the difference was significant. Diarrhea occurred in 35.1% of the patients with chronic development of hypoalbuminemia, but only 9.9% of the patients with rapid development of hypoalbuminemia had diarrhea; that difference also was significant. CONCLUSIONS: We concluded that the hypoalbuminemia-related diarrhea during tube feeding was significantly higher in patients with albumin levels less than 2 g/dl, and the patients with hypoalbuminemia due to chronic malnutrition had a significantly higher incidence of diarrhea than those with acute malnutrition, such as burned patients.

Acute Disease↗
PubMed1993

A reappraisal of cholangiocarcinoma in patient with hepatolithiasis.

BACKGROUND: Hepatolithiasis associated with cholangiocarcinoma is not often encountered. During the past 3 years, an increased incidence of patients with hepatolithiasis associated with cholangiocarcinoma was noted. Data were needed to reliably determine the incidence of this disease. METHODS: Data concerning the relationship between cholangiocarcinoma and hepatolithiasis are presented. The treatment modalities and factors that influence long-term survival are discussed. RESULTS: The overall incidence of cholangiocarcinoma in association with hepatolithiasis was 5.0% (55 in 1105). Before 1987, 65% of cholangiocarcinoma in association with hepatolithiasis was diagnosed postoperatively. After 1987, the incidence of accurate preoperative diagnosis increased (22.8%), and in most of the other instances (62.8%), the diagnosis was made at laparotomy. Surgical procedures consisted of common bile duct exploration with T-tube drainage (100%) and hepatectomy (38.2%). Mortality for patients who underwent surgery was 5.4%; they died of recurrent cholangitis. The overall median survival time of patients with cholangiocarcinoma in association with hepatolithiasis was 10.4 months; the 1-, 2-, and 4-year cumulative survival rates were 30.0%, 12.7%, and 3.6%, respectively. Patients with hepatectomy or the presence of mucobilia had better survival rates (P < 0.05). CONCLUSIONS: The overall incidence of hepatolithiasis associated with cholangiocarcinoma was 5%. In most patients with cholangiocarcinoma in association with hepatolithiasis, diagnosis can be made preoperatively and at laparotomy. Patients with hepatectomy or presence of mucobilia had better survival rates.

Adenoma, Bile Duct↗
PubMed1993

Solid and papillary neoplasm of the pancreas. Emphasis on surgical treatment.

Six Chinese females with solid and papillary neoplasms of the pancreas underwent surgery. Mean age was 26 years. The most common clinical sign was a large palpable abdominal mass. One patient presented with shock and acute onset of abdominal pain with positive peritoneal signs due to rupture of the tumor. The surgical procedures included Whipple's operation in one patient with a tumor at the head of pancreas, a 75% distal pancreatectomy in two patients with tumor of the body or tail of the pancreas, a partial pancreatectomy and pancreaticogastrostomy in one patient with a tumor at the neck and body of the pancreas, total excision in one patient with a tumor of the body of the pancreas, and a Roux-en-Y cystojejunostomy in one patient with a huge unresectable tumor of the head and body of the pancreas. During the follow-up period of from 40 to 83 months, four patients had survived and two had died of causes unrelated to the tumor in the differential diagnosis of a pancreatic mass, especially in young women with long histories of epigastric masses. Resection is the treatment of choice when the tumor is resectable. For unresectable tumors, a bypass procedure might be an alternative.

Adolescent↗
PubMed1993

Dose titration study of isradipine in Chinese patients with mild to moderate essential hypertension.

In order to assess the effective dose, tolerability, and safety of isradipine as a monotherapeutic antihypertensive agent for Chinese patients in Taiwan, an open trial was carried out. This study consisted of a 2-week, placebo, run-in period and an 8-week active treatment period, starting with isradipine 1.25 mg twice daily (bid) for the first 4 weeks, followed by 2.5 mg bid if the blood pressure was not normalized (diastole < 90 mmHg). One hundred and one patients (M/F = 48:53) were valid for efficacy analysis. Their age ranged from 30 to 64 years (mean +/- SD, 52 +/- 8). The blood pressure before active treatment was 160 +/- 2/104 +/- 1 mmHg. At the end of treatment period I (week 4), 12-14 hours after the last dose, 38 (37.6%) patients were normalized and 47 (46.5%) subjects responded (diastolic blood pressure reduction > or = 10 mmHg). At week 8, 68 (67.3%) patients were normalized and 79 (78.2%) subjects responded. Isradipine reduced both systolic and diastolic blood pressures within 2 weeks of treatment. There were no significant differences in blood pressure reduction between both genders and among age groups. Safety analysis showed two subjects with severe flushing, dizziness, and palpitation who used the dose of 1.25 mg bid. They withdrew from the study. The adverse reactions of other patients were transient, mild, and tolerable. Most of the side effects were related to vasodilatation, but edema was not found. There was no change in body weight or heart rate, nor any atrioventricular conduction disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Left-to-right shunt through patent foramen ovale in adult patients with left-sided cardiac lesions: a transesophageal echocardiographic study.

To define the prevalence rate of left-to-right interatrial shunt through patent foramen ovale in adults with symptomatic left-sided cardiac lesions, 56 patients were examined with transthoracic and transesophageal echocardiography and cardiac catheterization. By transesophageal echocardiography, 15 patients (group A) were found to have left-to-right interatrial shunt through patent foramen ovale, constituting a prevalence rate of 27%. In group A, transthoracic echocardiography detected the interatrial shunt in two patients, and catheterization detected it in only one. The remaining 41 patients (group B) had no shunt demonstrated by either echocardiographic or catheterization examinations. In another 44 patients (group C) with no significant left-sided cardiac lesions, no interatrial shunt could be found by transesophageal echocardiography even though some of them had a patent foramen ovale. All patients with such shunt had left atrial size > 34 mm (45.1 +/- 6.0 mm), left atrial pressure > 13 mm Hg (23.4 +/- 7.6 mm Hg), and pressure gradient between left and right atria > 10 mm Hg (19.3 +/- 5.2 mm Hg). These findings support the concept that in the presence of a patent foramen ovale any left-sided cardiac lesion increasing left atrial size and pressure may induce left-to-right interatrial shunt through this channel and that the prevalence rate is much higher than generally acknowledged.

Adult↗
PubMed1993

The use of indirect calorimetry in critically ill patients--the relationship of measured energy expenditure to Injury Severity Score, Septic Severity Score, and APACHE II Score.

The nutritional needs of critically ill septic patients or patients with multiple injuries are often difficult to estimate. Indirect calorimetry can simply and accurately determine individual caloric and nutritional needs, especially in cases of critically ill patients with complicated injuries. This prospective study compared the measured energy expenditures of 30 patients using indirect calorimetry with their predicted basal energy expenditure according to the Harris-Benedict equation, or their calculated energy expenditure derived from basal energy expenditure times, an activity factor, and a stress factor. These numbers were then used to evaluate the relationship between measured energy expenditure, measured energy expenditure per kilogram, and four specific scoring systems--the Septic Severity Score (SSS), the Injury Severity Score (ISS), the Trauma Score (TS), and APACHE II. The results showed the severity of sepsis or trauma correlated with the measured energy expenditure per kilogram of body weight. Among the 15 septic patients, in whom the measured energy expenditure per kilogram was 42.2 +/- 2.6 kcal/kg, the SSS provided a better predictor of energy needs and closer correlation with measured energy expenditure per kilogram (r = 0.69, Y = 1.41 + 0.72 X). Their stress factors could be modified as "0.97 + 0.0125 x SSS" to get a more accurate Harris-Benedict calculation. For the 15 patients with multiple injuries in whom the measured energy expenditure per kilogram was 34.9 +/- 1.6 kcal/kg, the ISS offered the best correlation with measured energy expenditure per kilogram (r = 0.84, Y = -31.47 +/- 1.73 X). Their stress factors could be modified as "1.04 + 0.0077 x ISS" to get a more accurate Harris-Benedict calculation.

Adult↗