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Biomedical subjects

M F Chen

Publications and source records attributed to M F Chen.

At least 271 records · Page 15Linked to original sources
PubMed1992

Calcium transport by rat liver plasma membranes during sepsis.

The effects of sepsis on the ATP-dependent Ca2+ transport in rat liver plasma membranes were investigated. Sepsis was induced by cecal ligation and puncture (CLP). Control rats were sham-operated. The results show that the ATP-dependent Ca2+ transport by liver plasma membranes was not affected during early sepsis (9 hr after CLP) but was decreased by 30-50% (P < 0.05) during late sepsis (18 hr after CLP). Kinetic analysis of the data indicates that during late sepsis, the Vmax values for ATP and for Ca2+ were decreased by 38.5% (P < 0.05) and 41.8% (P < 0.05), respectively, while the Km values for ATP and Ca2+ remained unchanged. Mg2+ stimulated ATP-dependent Ca2+ transport. The Mg(2+)-stimulated activity was unaffected during early sepsis but was decreased by 34-63% (P < 0.05) during late sepsis. These data demonstrate that ATP-dependent Ca2+ transport in rat liver plasma membranes was impaired during late sepsis and that the impairment is associated with a mechanism not affecting the affinity of the Ca2+ transporter for ATP and Ca2+. Since plasma membrane ATP-dependent Ca2+ transport plays an important role in the regulation of intracellular Ca2+ homeostasis in hepatocytes, an impairment in the ATP-dependent Ca2+ transport by liver plasma membranes during late sepsis may have a pathophysiological significance in contributing to the development of altered hepatic metabolism during septic shock.

Adenosine Triphosphate↗
PubMed1992

Localization of obscure gastrointestinal bleeding by technetium 99m-labeled red blood cell scintigraphy.

When a bleeding source from the gastrointestinal (GI) tract cannot be identified with conventional diagnostic studies, it is known as GI bleeding of an obscure origin. In the past three years, in vivo Technetium 99m-labeled red blood cell scintigraphy (RBC scan) has been added to our armamentarium for the diagnosis of obscure GI bleeding. Out of a total of 26 cases, the bleeders could be detected in 12 or 46.2% by RBC scan. The time required ranged from 15 minutes to 24 hours (median, one hour). In 14 patients with active bleeding during the scan period, 11 had positive scans (sensitivity, 78.6%). In 12 patients with inactive bleeding, 11 had negative scans (specificity, 91.7%). Angiography was conducted in nine cases, with all showing negative findings; however, six of them had a positive focus by RBC scan. Laparotomy was performed in seven scan-positive patients, and in three scan-negative patients because of a positive Meckel's scan (two cases) or recurrent bleeding (one case). Of the 12 scan-positive patients, incorrect localization was noted in two patients due to rapid transit of the labeled RBC in the small bowel. False localization could be prevented by shortening the sequential imaging interval. It is concluded that an RBC scan is a very sensitive and safe tool for detection of GI bleeding of an intermittent nature, because the bleeder can be monitored for 24 hours after a single injection. It can be used as a preangiographic screening test and to guide the surgeon in surgical planning or decision-making.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Octreotide in the management of postoperative enterocutaneous fistulas and stress ulcer bleeding.

We report two clinical experiences in the treatment of postoperative enterocutaneous fistula and stress ulcer bleeding with octreotide acetate (Sandostatin). In both patients, upper gastrointestinal bleeding occurred 7 days after operation, and the bleeding proved to be stress ulceration, by panendoscopic examination. Enterocutaneous fistulas also were found in both patients. One was high output (750 ml/day), and the other was low output (50 ml/day). Octreotide 50-100 micrograms was given subcutaneously every 8 h. After three doses of octreotide, a significant reduction in fistula output and control of the stress ulcer bleeding were noted. The fistulas closed promptly after nine doses of octreotide, but the first patient's fistula recurred 2 days later, with fluid losses of about 100-200 ml/day. This fistula closed spontaneously 1 month after discharge. Octreotide appears to be useful as an adjunct to the conventional treatment of enterocutaneous fistulas, especially those complicated by stress ulcer bleeding.

Aged↗
PubMed1992

A prospective study of the effect of cholecystectomy on duodenogastric reflux in humans using 24 hour gastric hydrogen monitoring.

Duodenogastric reflux (DRG) was quantified with continuous 24 hour monitoring of gastric pH in 30 patients, 12 of whom underwent operation for repair of an inguinal or femoral hernia used as a control group. The remaining 18 patients with noncomplicated gallstone disease underwent a simple cholecystectomy. Eight weeks after the operation, the tests were repeated. We found that patients with cholelithiasis were accompanied with DGR or alkaline shift more often than the patients in the control group and cholecystectomy decreased the percentage of time that gastric pH was less than two and increased the time at four and six. Although cholecystectomy itself does cause DGR, most patients with DGR may be asymptomatic.

Adult↗
PubMed1991

Gastrin-releasing peptide gene products in midtrimester human fetal lung with and without maternal smoking history during pregnancy.

A preliminary morphological study on human fetal lungs with positive maternal smoking history demonstrated alterations of the neuroepithelial bodies (NEBs). We studied human fetal lung tissue between the gestational ages of 12 weeks and 19 weeks, comprising 12 cases with a smoking history during pregnancy (Group 1) and eight cases without a smoking history during pregnancy (Group 2). We demonstrated, by immunocytochemistry, the presence of gastrin-releasing peptide (GRP) gene products: GRP 14-27 in all 20 cases, and C terminal peptide of pro-GRP (C-flanking peptide) in 17 cases. Quantification of the neuroepithelial cells (NECs) was made by computer-enhanced image analysis using the Context Vision system, expressing 1) the total stained areas of the NECs per unit area of section and 2) the total staining areas of the NECs per unit area of airway epithelium, measured as the area of cytokeratin immunoreactivity in an adjacent section. The results show no statistically significant difference between groups 1 and 2 for either GRP 14-27 or C-flanking peptides. The apparent lack of influence of maternal smoking during pregnancy on the expression of GRP gene products in the NECs could be a reflection of inherently reduced reactivity of the cells during the gestation period studied. However, a larger series is needed before any conclusions can be made. Alternatively, the adverse effects of smoking might be reflected during the canalicular phase of lung development; an increased immunoreactivity appears to be present during that period. The expression of pro-GRP gene products in the pulmonary NECs of older fetuses and neonates with maternal smoking history during pregnancy requires further study.

Female↗
PubMed1991

The influence of FK-506 on the thymus and spleen in normal C3H/He mice: flow cytometric analysis of lymphocyte subpopulations.

Although FK-506 has been widely investigated as a potent suppressor of organ allograft rejection in animals, little is known about the effect of FK-506 on normal animals. In this study, we investigated the influence of FK-506 on the thymus and spleen in normal C3H/He mice at the age of 5 weeks. Mice were given dosages of FK-506 varying between 0.3 and 30 mg/kg/day intramuscularly for 5 days. After treatment with FK-506, the total number of lymphocytes in the thymus was significantly decreased in a dose-dependent manner; however, no change was evident in the total number of lymphocytes in the spleen. FK-506 also influenced the immunophenotypes in thymocytes, but not in splenocytes. The absolute number of CD4+ CD8- or CD4- CD8+ thymocytes decreased significantly in the 0.3 mg/kg/day-treated group. CD4+ CD8-, but not CD4-CD8+ thymocytes decreased further in the 1 mg/kg/day-treated group. Neither subpopulation decreased any further with continuing administration. On the other hand, the number of CD4+ CD8+ thymocytes did not decrease significantly in the 0.3 mg/kg/day-treated group, whereas it did decrease significantly in the 1 mg/kg/day-treated group, decreased further with the increase in dosage of FK-506, and decreased markedly in the 30 mg/kg/day group, The number of CD4-CD8-thymocytes did not show any change, even in the high-dosage groups. These results indicate that FK-506 influences the subpopulations of thymocytes according to its dosage. At a lower dosage, it affects mature CD4+ CD8- or CD4- CD8+ cells, but not immature CD4+ CD8+ and CD4-CD8- cells.2

Animals↗
PubMed1991

Human liver regeneration after major hepatectomy. A study of liver volume by computed tomography.

Regeneration of the remnant liver after major hepatectomy in humans was studied by computed axial tomography (CT) in 12 noncirrhotic and five cirrhotic patients. Liver volumes were measured by abdominal CT 3 days, 10 days, 3 months, 6 months, 1 year, and 1.5 years after resection. Of the 17 patients, liver remnant volume was increased in 21.2% +/- 6.7% and 30.6% +/- 12.7% at 3 months and 6 months after resection, respectively. Noncirrhotic livers were 28.4% +/- 9.5% and 48.4% +/- 17.8% larger at 3 and 6 months. For cirrhotic livers, the increase was 8.5% +/- 3.6% and 12.9% +/- 4.5%. In five patients with right hepatectomy (65% resection), the liver remnant volumes were increased 38.4% +/- 11.7%, 48.0% +/- 16.2% and 95.1% +/- 4.5% at 3 months, 6 months, and 1 year after resection, respectively. In seven patients with right partial hepatectomy (30% to 35% resection), the percentages were 7.4% +/- 3.2%, 21.8% +/- 8.4%, and 63.9% +/- 18.3% and in five patients with left lateral segmentectomy (15% resection), they were 15.6% +/- 8.2%, 27.8% +/- 12.2%, and 33.0% +/- 14.5% 3 months, 6 months, and 1 year after resections, respectively. Noncirrhotic livers showed better regeneration than cirrhotic livers. Complete regeneration took about 1 year. The noncirrhotic liver that underwent right lobectomy also needed 1 year to double its postresection volume.

Adult↗
PubMed1991

Lysis of murine macrophages by lymphokine-activated killer-like cells induced by BCG in vitro.

The lymphokine-activated killer (LAK)-like activity was found to be induced in mouse splenocytes cultured together with Bacillus Calmette-Guérin (BCG). The killer cells induced by BCG were capable of killing both NK-sensitive (YAC-1, P388D1) and NK-resistant (P815) tumor cells. As an important finding, they also lysed syngeneic macrophages (M phi). The anti-M phi killer activity appeared on day 2, and reached a peak on day 5 of culture. Phenotype analysis of the killer cells by depletion techniques using monoclonal antibody (mAb) and complement indicated that the majority of these anti-M phi killer cells were Thy-1+ and asialo GM1+. This M phi cytolysis could be inhibited by the addition of cold M phi, YAC-1 tumor cells, and P815 tumor cells, suggesting that the same population of the effector cells recognize M phi and tumor cells. The addition of anti-MHC class I, anti-MHC class II, anti-L3T4, or anti-Ly-2 mAb directly to assay cultures did not affect anti-M phi cytolysis, suggesting that the MHC molecules are not involved in the cytolysis of M phi by the BCG-induced killer cells. The addition of anti-LFA-1 mAb partially inhibited the cytotoxicity, suggesting importance of the contact between targets and effectors in the cytolysis. Our present data suggest that activation of murine lymphocytes with BCG induces LAK-like cells capable of killing a wide variety of tumor cells as well as M phi and this anti-M phi cytolysis is mediated by nonspecific killer cells.

Animals↗
PubMed1991

Heterotopic heart transplantation--a life-saving procedure with a size-mismatched donor.

A 32-year-old B-type male weighing 60 kg suffered from end-stage dilated cardiomyopathy. Although aggressive medical treatment with dobutamine 21 micrograms/kg/min, dopamine 17 micrograms/kg/min, digoxin 0.25 mg i.v. once daily, furosemide 40 mg i.v. every 6 h, and bumetanide 0.5 mg i.v. every 6 h were given, he was finally ventilator dependent for the last 3 weeks until a B-type donor weighing 42.5 kg was found. Because of the 29.2% weight mismatch, a heterotopic heart transplantation was performed. Posterior plication mitral annuloplasty was also performed to correct the severe mitral regurgitation of the recipient heart. Postoperatively the patient remained respirator dependent for 17 days and was finally discharged in good condition on the 46th postoperative day.

ABO Blood-Group System↗
PubMed1991

Effect of oral administration of glycyrrhizin on the pharmacokinetics of prednisolone.

The pharmacokinetics of total and free prednisolone (PSL) in six healthy men, with or without pretreatment with oral glycyrrhizin (GL), was investigated to confirm whether oral administration of GL influences the metabolism of PSL in man. Each subject received an intravenous administration of 0.096 mg/kg of prednisolone hemisuccinate (PSL-HS) with or without pretreatment with 50 mg of oral GL four times. Blood samples were taken from a peripheral vein at 5, 10, 15, 30, 45 min and 1, 1.5, 2, 3, 4, 6, 8, 10, 12 and 24 h after the start of PSL-HS infusion. The concentrations of total PSL in plasma were analyzed by high-performance liquid chromatography, and the free PSL was measured by an isocolloidosmolar equilibrium dialysis method. The pharmacokinetic parameters of PSL were determined by non-compartment analysis. Oral administration of GL was found to significantly increase the concentrations of total PSL at 6, 8 h, and of free PSL at 4, 6 and 8 h after PSL-HS infusion. Moreover, oral administration of GL was also found to modify the pharmacokinetics of both total and free PSL. After oral administration of GL, the area under the curve (AUC) was significantly increased, the total plasma clearance (CL) was significantly decreased, and the mean residence time (MRT) was significantly prolonged. However, the volume of distribution (Vdss) showed no evident change. This suggests that oral administration of GL increases the plasma PSL concentrations and influences its pharmacokinetics by inhibiting its metabolism, but not by affecting its distribution.

Administration, Oral↗
PubMed1991

The clinical characteristics of acute myocardial infarction in aged patients.

Age is one of the important prognostic factors for acute myocardial infarction. This study was performed to clarify the clinical characteristics and outcome of acute myocardial infarction in Chinese geriatric patients. The study subjects included 742 patients, divided by age into 2 groups: Group A greater than or equal to 65 years, 321 cases; and Group B less than 65 years, 421 cases. The following characteristics were compared between these 2 groups: sex composition; presence of chest pain, heart failure or shock at presentation; cardiac functional status; occurrence of various complications, and follow-up data. Males were less prominent in the older group: 229 patients (71.3%) in Group A, and 371 patients (88.1%) in Group B. At onset, the older patients presented with less chest pain (72% vs 86.5%) and more heart failure (35.2% vs 20.2%), but the occurrence of shock was similar (5.9% vs 4.5%, for Groups A and B, respectively). During hospitalization, more patients in Group A showed impaired cardiac function, as evidenced by a higher percentage of patients identified as in Killip class III or IV (35.4% vs 21.1%). Concerning complications, the older group showed a higher incidence of hypotension, low cardiac output, lung edema, frequent premature ventricular beats, atrial flutter and/or fibrillation, complete heart block and intraventricular conduction defects, but ventricular septal defects, ventricular tachycardia and ventricular fibrillation did not show any difference in occurrence. Life table analysis showed that the survival rate was significantly lower for Group A during the follow-up period of 5 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1991

Heart diseases following radiotherapy.

Three women had cardiac complaints 10-17 years after a radical mastectomy and radiotherapy for cancer of the left breast. Their ages were 42, 43 and 57 years, respectively. The first patient had a precocious coronary artery disease (CAD). She had segmental stenosis in the middle and distal portions of the left main coronary artery and pericardial fibrosis. Symptoms and signs of severe pericardial constriction became the problem after bypass surgery. She died 1 year later due to cardiorespiratory failure. The second case had sick sinus syndrome presenting a prolonged pause for 12 seconds alternating with tachy- and bradyarrhythmias, a complete atrio-ventricular block in association with pericardial effusion plus aortic and mitral valvular regurgitation. The condition improved after the implantation of a permanent pacemaker. To date, this is a very rare complication of radiation induced panconduction disturbance. The third patient had significant stenosis in the proximal portion of the left anterior descending coronary artery and myocardial fibrosis was proven by an endocardial biopsy. She had an uneventful course after medical treatment.

Adult↗
PubMed1991

Early nasoduodenal feeding for the post-biliary surgical patient.

The effects of early postoperative nasoduodenal feeding on nutrition and metabolic response were studied using 24 patients after biliary surgery. The patients were randomly divided into two groups with 12 in each group. Group I was fed via a nasoduodenal tube from the first postoperative day but control group II was not fed until the fourth postoperative day. The hospital blenderized tube feeding diet provided the enteric nutrition (17% protein, 33% fat and 50% carbohydrate). The nutritional status of the 2 groups was compared over a one week period. The changes in nitrogen balance were measured daily for 8 days. The group fed early had a significantly reduced negative nitrogen balance when compared to the group whose feeding was started later. (-1.91 +/- 1.05 g/day vs -5.84 +/- 0.48 g/day). There was no difference in serum albumin and transferrin levels, but serum prealbumin levels in the group fed early were more desirable than those of the control group (from 15.8 +/- 2.5 mg/dl to 28.9 +/- 3.8 mg/dl vs from 18.0 +/- 2.0 mg/dl to 25.9 +/- 3.9 mg/dl). Total lymphocyte count was also better in the group fed early than in the controls (from 1,325 +/- 204 cells/mm3 to 2,655 +/- 584 cells/mm3 vs from 1,277 +/- 188 cells/mm3 to 1,877 +/- 440 cells/mm3). All the patients in group I felt better than those in group II during the study course. These results indicated that those patients provided with early nasoduodenal feeding after a biliary operation displayed a better nitrogen balance, and a faster increase in short half life visceral protein and total lymphocyte count.

Duodenum↗
PubMed1991

Protection of liver ischemia due to inflow occlusion using prior perfusion with hepatic protective solution in dogs.

Temporary occlusion of hepatic inflow is a useful maneuver to reduce hemorrhage from liver trauma and difficult hepatic resections. The liver can be protected with a hepatic protective solution before inflow occlusion, just as the stopped heart is protected by a cardioplegic solution during open heart surgery. Twenty dogs were divided into two groups. The portal inflow of group A was infused via the mesenteric venous branch with a hepatic protective solution composed of 250 mg of hydrocortisone, 15 mEq of KC1, 6 mL of 0.1 N HC1, 5 mL of 10% magnesium sulfate and 250 mg of dextrose in one liter of cold lactated Ringer's solution. Group B was infused with cold lactated Ringer's solution as a control. The hepatic artery and portal vein were isolated and then clamped for 30 minutes. The elevation of serum GOT and GPT after release of the clamps was significantly greater in group B, especially during the first 48 hours. The levels of alkaline phosphatase and total bilirubin were also higher in group B until the 7th day. The results liver biopsies 3 hours after release of the clamps revealed marked congestion and destruction of hepatocytes in group B. We conclude that liver perfusion with a hepatic protective solution before inflow occlusion results in less damage to liver tissue and less impairment of liver function. Such protection is important in liver surgery.

Animals↗
PubMed1991

Secretory state of gastric mucosa does not protect against acute gastric mucosal injury induced by hemorrhagic shock in rats.

The protective effect of the secretory state of gastric mucosa against acute gastric mucosal injury due to hemorrhagic shock was investigated in rats with tetragastrin infusion. A total of 26 male Spraque-Dawley rats were divided into 3 groups (n = 6, 8, and 12, respectively). Tetragastrin (8 micrograms/Kg/h) was added into the normal saline infusion (5 ml/h) in group 3, but not in the other 2 groups. The mucosal surface was instilled with 0.1 N HCl (pH = 1) in group 2, with normal saline (pH = 7) in group 1, and with nothing in group 3. Hemorrhagic shock at 40 mmHg of arterial pressure was induced by withdrawing blood from the femoral artery, and was maintained at this level for 20 minutes; later, the shed blood was re-infused. During hemorrhagic shock, scattered areas of white circumscribed white lesions appeared on the mucosal folds of the glandular region in all of group 2 and in 8 (with gastric pH less than 3) of group 3, yet did not appear in group 1 or in the remaining 4 (with gastric pH greater than 3) of group 3. After reinfusion, varying degrees of mucosal hemorrhage from the whitened areas occurred in all of group 2 and in 8 (with pH less than 3) of group 3, but in only one of group 1. The severity of acute gastric mucosal injury in group 2 and group 3 (n = 8, with gastric pH less than 3) was significantly greater than group 1. However, it was not significantly different between groups 2 and 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Influence of age on results of resection of hepatocellular carcinoma.

One hundred and fifty-eight elective hepatectomies carried out between 1976 and 1989 for hepatocellular carcinoma were classified into three groups according to age: group I (n = 20) under 30 years of age; group II (n = 102) 30 to 60; and group III (n = 36) over 60. The number of operations carried out on patients in group III has increased since 1983, and the types of hepatic resection in the three different age groups were slightly but not significantly different. The incidence of small tumours (diameter less than 5 cm) and associated cirrhosis were relatively low in the younger patients. Postoperative complications developed in 4 patients (20%) in group I, 18 (18%) in group II and 8 (22%) in group III, the main ones being hepatic failure and intraabdominal sepsis. Operative mortality was 4%; one patient (5%) died in group I, 4 (4%) in group II, and 2 (6%) in group III, and the principal causes were hepatic failure and massive haemorrhage. Hepatic resection for hepatocellular carcinoma in most patients over 60 years old was associated with slightly higher operative morbidity and mortality, but the risks were such that we recommend that operation should not be denied to selected patients in this age group.

Adult↗
PubMed1991

Flow cytometric DNA analysis of hepatocellular carcinoma: preliminary report.

Flow cytometric DNA analysis was performed in 50 paraffin-embedded specimens of clinical hepatocellular carcinoma (HCC) after hepatic resections. The DNA distribution pattern was classified in two types, diploid and aneuploid, according to the degree of dispersion on the DNA histogram. The major DNA pattern of HCC in this report proved to be aneuploid (78%), although 22% of tumors revealed a diploid pattern. The serum alpha-fetoprotein level exceeded 40 ng/ml in 86.1% of the aneuploid tumors and in 13.9% of the diploid tumors (p less than 0.05). We found no correlation between DNA distribution and hepatitis B surface antigen positivity, the presence of liver cirrhosis or tumor size. Additionally we noted no significant correlation between the DNA pattern and survival rates in patients with HCC who underwent hepatic resection.

Adolescent↗