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Biomedical subjects

M F Chen

Publications and source records attributed to M F Chen.

At least 253 records · Page 14Linked to original sources
PubMed1993

Protection by oestradiol against the development of cardiovascular changes associated with monocrotaline pulmonary hypertension in rats.

1. We studied the effects of oestradiol 17 beta on the development of pulmonary vascular changes and right ventricular (RV) hypertrophy in response to monocrotaline in male Sprague-Dawley rats. 2. Rats were treated with either placebo or oestradiol 17 beta (10 mg) in the form of slow release pellets implanted subcutaneously 48 h before monocrotaline administration. Rats were injected with either saline or a single dose of monocrotaline (60 mg kg-1, i.m.). Pulmonary vascular changes and RV hypertrophy were studied at 4 weeks following monocrotaline administration. 3. Monocrotaline induced a significant increase in the ratio of right ventricle (RV) to left ventricle-plus-septum (LV + S) weights. Monocrotaline-treated rats also showed significant myointimal proliferation in small pulmonary arteries, decrease of arterial numbers and increase in the number of abnormal alveolar macrophages. 4. Oestradiol 17 beta attenuated myointimal hyperplasia in pulmonary vessels, decreased the RV/(LV + S) ratio in monocrotaline-treated rats. Oestradiol 17 beta had no significant effect on control animals. 5. Oestradiol treatment prevented the increase in lung wet to dry weight ratio, observed 7 days post monocrotaline administration. 6. These results suggest that oestradiol 17 beta protects against the pulmonary vascular remodelling and RV hypertrophy associated with monocrotaline-induced pulmonary hypertension in the rat. Oestradiol also protects against microvascular leak observed in the early days of lesion.

Animals↗
PubMed1993

Differences in acupuncture point SP-10 and non-acupuncture point following subcutaneous injection of Tc-99m pertechnetate.

A new method of radionuclide venography, namely SC-RNV, by subcutaneous injection of Tc-99m pertechnetate at acupuncture points was recently developed in our laboratory. The time-activity curve of SC-RNV can be divided into 3 phases as: the phase of diffusion of radioisotopes through the subcutaneous space, the phase of entrance of radioisotopes into intravascular space to reach a peak concentration and the phase of equilibrium state of radioisotopes in the intravascular space. In this study, we used the 3 phases of SC-RNV to evaluate the absorption of Tc-99m pertechnetate injected subcutaneously in the acupuncture point SP-10 (Xuehai) and in a non-acupuncture point near SP-10. The results revealed that the absorption of Tc-99m pertechnetate via SP-10 was significantly greater than that of non-acupuncture point, evidenced by shorter phase 1, higher peak activity and greater accelerating rate of phase 2. This suggests that the absorption of radioisotopes from acupuncture point is faster and greater than that of non-acupuncture point.

Absorption↗
PubMed1993

Biphasic intracellular redistribution of alpha 1-adrenergic receptors in rat liver during sepsis.

Changes in the distribution of alpha 1-adrenergic receptors in two subcellular fractions, the plasma membrane and the light vesicle, of rat liver during sepsis were studied using [3H]prazosin binding and photoaffinity labeling with [125I]arylazidoprazosin in combination with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Sepsis was induced by cecal ligation and puncture (CLP). Septic rats exhibit two metabolically distinct phases: an initial hypermetabolic (hyperglycemic) phase (9 h after CLP; early sepsis) followed by a hypometabolic (hypoglycemic) phase (18 h after CLP; late sepsis). [3H]prazosin binding studies show that during early sepsis, the maximal binding capacity (Bmax) was increased by 35% in plasma membranes but was decreased by 28% in light vesicles; while during late sepsis, the Bmax was decreased by 30% in plasma membranes but was increased by 33% in light vesicles. The photoaffinity labeling studies revealed two major binding peptides with M(r) of 77,000 and 68,000 Da and one minor binding protein with M(r) of 39,000 Da. The total binding for the three labeled peptides during early sepsis was increased by 26% in plasma membranes but was decreased by 33% in light vesicles, while during late sepsis the total binding was decreased by 19% in plasma membranes but was increased by 35% in light vesicles. These data indicate that alpha 1-adrenergic receptors in the rat liver were externalized from light vesicles to plasma membranes during the hyperglycemic phase while they were internalized from surface membranes to intracellular sites during the hypoglycemic phase of sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Angiosarcoma of the small intestine after radiation therapy: report of a case.

A case of angiosarcoma of the small intestine is reported. The patient had a past history of cervical cancer, for which she had received radiotherapy eight years previously. She presented with an acute abdomen, and a distal jejunal perforation was found during emergency surgery. The patient expired due to reperforation of the bowel with peritonitis two months after discharge. The pathology of the resected bowel segment showed evidence of previous radiotherapy and infiltration by angiosarcoma involving all layers of the bowel, which had perforated. Submucosal fibrosis and angioectasia indicative of radiation therapy were also evident. The findings suggest that angiosarcoma of the small intestine may occur at sites of previous radiation therapy and may be causally related.

Female↗
PubMed1993

Augmentation of liver regeneration with glucagon after partial hepatectomy in rats.

The direct stimulating effect of glucagon on partially hepatectomized rats was studied. Following a 70% hepatectomy, male Wister rats were divided into three groups. Group I received glucagon 0.8 mg/kg/day; group II received hydrocortisone 10 mg/kg/day; and group III received normal saline as a control. Their blood sugar levels and food intake were not significantly different. After one week, the regenerated livers in group I were larger (9.69 +/- 0.30 cm3 vs 8.29 +/- 0.34 cm3 in group II and 8.20 +/- 0.10 cm3 in group III), and heavier (9.83 +/- 0.28 g vs 8.52 +/- 0.33 g in group II and 8.75 +/- 0.21 g in group III) than those in the other two groups. The mitotic index in group I was also higher. The results suggest that glucagon has a direct hepatotrophic effect and enhances regeneration of the liver in rats.

Animals↗
PubMed1993

[Laparoscopic versus open cholecystectomy: a prospective randomized study].

A prospective randomized study of laparoscopic versus open cholecystectomy was carried out fro December 1991 to June 1992 at the Chang Gung Memorial Hospital. Laparoscopic cholecystectomy was performed in 50 cases in group A and open cholecystectomy in 51 cases in group B. All patients had a preoperative history of biliary tract disease and most had gall stones proved by sonography. There was no operative mortality in either group and the postoperative complication rates were 4.4% and 2% in group A and B respectively (p > 0.05). Prolonged operative time in group A was 85.7 +/- 25.2 min vs group B 48.0 +/- 13.9 min (p < 0.001). Postoperative bowel function recovery with toleration of a regular diet in group A was faster than group B (45.6 +/- 19.2 hrs vs 55.2 +/- 11.0 hrs, p < 0.001). The need for postoperative narcotic drugs with demerol injection was less in group A (40%) than group B (86%) (p < 0.001). The total cost for group A was NT $42139 +/- 7135 and for group B was NT $38085 +/- 7578 (p > 0.05). The interval of return to full activity for group A was shorter than group B (12.8 +/- 8.8 days vs 35.9 +/- 20.6 days respectively p < 0.001). Recurrent symptoms within the 6 to 13 month postoperative follow up period was 8% in group A and 11.7% in group B (p > 0.05). Only one patient in group B was proved to have a recurrent common bile duct stone by endoscopic retrograde cholangiography and received choledocholithotomy again.

Adult↗
PubMed1993

Liver transplantation for a hepatitis B-related cirrhotic patient.

A patient with chronic end-stage liver cirrhosis resulting from a hepatitis B viral infection had a successful liver transplantation performed on 1 July 1991. Preoperative serology revealed that both HBsAg and HBeAg were positive, and the anti-HBs antibody was negative. Immunoprophylaxis included active immunization, as well as injections of large doses of hepatitis B immunoglobulin (HBIG) given perioperatively to reverse the antigen status. The patient has been anti-HBs antibody positive for more than 10 months since the transplantation. The immunoprophylaxis protocol used has been effective in the prevention of hepatitis B viral reinfection.

Adult↗
PubMed1993

The effects on basal anterior pituitary hormone concentrations by cranial irradiation in patients with nasopharyngeal carcinoma.

Hypopituitarism occurring in patients who received external cranial radiation therapy (RT) have been increasingly recognized. Fourteen healthy patients were collected as control Group I, and 25 patients with nasopharyngeal carcinoma (NPC) were enrolled as Group II. Another 18 NPC patients were enrolled as Group III. Blood was sampled from Group I, Group IIB (before RT), Group IIA (one week after RT) and Group IIIA (1 to 1.5 years after RT). The basal samples were taken for growth hormone (GH), adrenocorticotropic hormone (ACTH), cortisol, follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), thyrotropin (TSH), triiodothyronine (T3) and thyroxine (T4). The results showed the T3 level was statistically low in Group IIB compared with Group I. The serum GH and FSH (male only) levels were higher and with statistical significance in Group IIA compared Group IIB. Both GH and ACTH levels decreased and PRL increased with statistical significance in Group IIIA compared with Group IIA. The ACTH decreased with statistical significance in Group IIIA compared with Group IIB. Clinical damage to the pituitary is usually manifested months to years after RT. Therefore, a careful exclusion of these glands from radiation treatment fields is recommended whenever possible.

Adult↗
PubMed1993

Obturator hernia: a report of eight cases.

Obturator hernia is a rare problem that occurs predominantly in elderly, emaciated women. The diagnosis of obturator hernia is difficult to establish in most patients before an operation is performed. Both delayed diagnosis and delayed surgical intervention contribute to high mortality. From 1978 to 1992, eight cases of obturator hernia involved elderly females who had received operations at this hospital. Resection of the incarcerated bowel was required. The often debilitated condition of these patients and the frequent delay of diagnosis combined to produce significant operative mortality.

Aged↗
PubMed1993

[Successful embolectomy for acute mesenteric artery occlusion].

Although acute mesenteric ischemia causing bowel necrosis, a surgical emergency, has been diagnosed with increasing frequency today, it remains as lethal as it ever was, with a mortality rate of 70% to 80%. The high mortality rate can be attributed to delayed diagnosis and the presence of underlying disease. Earlier and more liberal use of angiography in patients with high suspicion of acute mesenteric ischemia is mandatory. We report here to a patient, presenting with acute abdomen and bloody stools, who was highly suspected to have superior mesenteric arterial occlusion. He received emergent angiography and successful embolectomy without bowel resection and second-look operation. The post-operative course was rather smooth. An aggressive surgical approach must be considered, and the second-look procedure should be used when the bowel viability is questionable at the first operation. Postoperative anticoagulation therapy should be given when indicated.

Acute Disease↗
PubMed1992

Branchio-oto-renal syndrome: further delineation of an underdiagnosed syndrome.

We report on a woman who was diagnosed with branchio-oto-renal (BOR) syndrome after 2 pregnancies complicated by oligohydramnios due to renal hypoplasia and agenesis. Both babies died neonatally of pulmonary hypoplasia. Histopathology of the temporal bones of the second child showed marked immaturity of the middle ear cleft, ossicles, facial nerve and canal, and cochlear nerve. Maternal renal ultrasound study was normal although intravenous pyelography indicated renal hypoplasia. The frequency of BOR syndrome among cases of recurrent fetal renal hypoplasia/dysplasia or agenesis is unknown, and parental renal ultrasonography may not identify a heritable renal defect. Investigations should include a family history, and examination of relatives to look for preauricular pits, lacrimal duct stenosis, and branchial fistulae and/or cysts. Hearing studies and IVP may be indicated.

Abnormalities, Multiple↗
PubMed1992

Posttreatment with sodium arsenite alters the mutational spectrum induced by ultraviolet light irradiation in Chinese hamster ovary cells.

Arsenic, a potent carcinogen, fails to induce gene mutations in mammalian cells. However, posttreatment of ultraviolet light (UV) irradiated cells with sodium arsenite synergistically enhances the mutation frequency on the hypoxanthine (guanine) phosphoribosyltransferase locus. To investigate the molecular mechanism of the comutagenic effects of sodium arsenite, we characterized the alterations of nucleotide sequences in 30 UV-induced and 39 sodium arsenite enhanced hprt mutants from Chinese hamster ovary K1 cells by direct sequencing of mRNA-PCR amplified cDNA. The majority of sequence alterations derived from UV irradiation (80%) and from sodium arsenite posttreatment (70%) were single base substitutions. UV irradiation induced all types of base substitutions. Among them, 57% were transversions. The frequency of transversions increased to 70% in sodium arsenite enhanced mutants. While base substitutions observed in UV-induced mutants were evenly distributed along with the whole coding region, exons 3 and 8 were most frequently mutated in sodium arsenite enhanced mutants. Sodium arsenite posttreatment did not alter the strand bias for mutation induction, i.e., 73% and 78%, of the mutations were located on the non-transcribed strand in UV-induced and sodium arsenite enhanced mutants, respectively. In contrast to UV-induced mutations, bases at the 5' position of TT and the 3' position of CT sequences were the most frequent mutation sites observed in sodium arsenite enhanced mutants. We hypothesize that sodium arsenite may interfere with the process of mutation fixation of TT and CT dimers during DNA replication.

Animals↗
PubMed1992

Effects of dietary supplementation with fish oil on atherosclerosis and myocardial injury during acute coronary occlusion-reperfusion in diet-induced hypercholesterolemic rabbits.

We studied myocardial injury during acute coronary occlusion-reperfusion and atherosclerosis in rabbits fed a high cholesterol diet with or without fish oil supplementation. New Zealand white male rabbits were divided into 3 groups. Eight control rabbits fed with laboratory standard rabbit chow were group I. In addition to the standard chow, 15 rabbits fed with a 1% cholesterol-enriched diet for 6 weeks were group II, and 10 rabbits fed with a 1% cholesterol-enriched and 10% fish oil supplemented diet for 6 weeks were group III. Acute coronary occlusion was induced by ligating the marginal branch of the left circumflex coronary artery for 1 h, followed by reperfusion for 4 h. Myocardial injury was assessed by tissue creatine kinase activities and amino-nitrogen concentrations from the ischemic (infarct) and nonischemic (normal) myocardium, and the infarct area/risk area ratios of the left ventricle. The surface area of the atherosclerotic lesions of the aorta and pulmonary artery was measured by planimeter. There was significantly more myocardial loss of creatine kinase and amino-nitrogen in the cholesterol-fed rabbits than the controls (p less than 0.01 and 0.02, respectively). The cholesterol and fish oil-treated rabbits had a nonsignificant reduction in myocardial loss of both agents as compared to their corresponding cholesterol-fed ones. The same trend was also found in the infarct area/risk area ratio. Fish oil treated rabbits had a good effect on the reduction of atherosclerotic lesions and tissue cholesterol levels in the aorta and pulmonary artery, but not in the left ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)

Amines↗
PubMed1992

Effects of dietary supplementation with fish oil on prostanoid metabolism during acute coronary occlusion with or without reperfusion in diet-induced hypercholesterolemic rabbits.

We studied the changes in myocardial and aortic concentrations of prostacyclin and thromboxane A2 during acute coronary occlusion with or without reperfusion in rabbits fed with a cholesterol-enriched diet with or without fish oil supplementation for a short (5 days) or long period (6 weeks). New Zealand white male rabbits were divided into 5 groups: Group I, 15 control rabbits fed with a laboratory standard rabbit chow. In addition to the standard chow, the 4 study groups were treated with cholesterol or fish oil. Group II, 17 rabbits fed with a 1% high cholesterol diet for 5 days. Group III, 16 rabbits fed with a diet containing 1% cholesterol and 10% fish oil for 5 days. Group IV, 17 rabbits fed with the same diet as group II for 6 weeks. Group V, 18 rabbits fed with the same diet as group III for 6 weeks. Each group of rabbits was randomly divided into the coronary occlusion or occlusion-reperfusion mode of experiment. Acute coronary occlusion was induced by ligating the marginal branch of the left circumflex coronary artery for 1 h. Subsequent reperfusion for 4 h was performed in the occlusion-reperfusion rabbits. The aortic tissue above the aortic valve and the ischemic and normal (nonischemic) areas of the left ventricle were excised for the measurement of 6-keto-PGF1 alpha and thromboxane B2 levels by radioimmunoassay. Both during coronary occlusion and occlusion-reperfusion, rabbits showed higher myocardial concentrations of 6-keto-PGF1 alpha and thromboxane B2 in the ischemic area than in the normal myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Pseudomembranous colitis in sickle cell disease responding to exchange transfusion.

We report a case of ischemic colitis with pseudomembrane formation in a 6 1/2-year-old boy with sickle cell disease that responded to medical management including exchange transfusion. This case was not associated with Clostridium difficile infection but with an elevation of serum levels of tumor necrosis factor alpha. This rare complication of sickle cell disease has been reported only in adults.

Abdominal Pain↗
PubMed1992

Mouse recombinant interferon-beta augments the induction of macrophage cytolytic activity by interleukin-2 in vitro.

We investigated the augmenting effect of mouse recombinant interferon-beta (MurIFN-beta) on the induction of macrophage (M phi) cytolytic activity by interleukin-2 (IL-2). C3H/He spleen cells were cultured with various doses of recombinant (r) IL-2 and/or MurIFN-beta for 4 days, and their cytotoxic activities against syngeneic M phi were assessed by a 4-h 51Cr-release assay. Although MurIFN-beta itself induced little M phi cytolytic activity, it significantly augmented the IL-2-induced cytotoxicity against M phi. MurIFN-beta showed a dose-dependent enhancement on the induction of anti-M phi activity by IL-2 with a peak at 2,000-10,000 U/ml, and the augmenting effect of rIFN-beta was more marked on lower doses of rIL-2 than on higher doses. This augmenting effect was also observed in IFN-alpha, whereas IFN-gamma showed no influence on IL-2-induced anti-M phi activity. The phenotype analysis by depletion technique with antibody and completement showed that anti-M phi effectors induced by either rIL-2 or the combination of rIL-2 and rIFN-beta were Thy-1+, asialoGM1+, L3T4-, and Ly2-. These results suggest that IFN-alpha or IFN-beta has a synergistic effect with IL-2 on the induction of nonspecific killer cells with M phi cytolytic activity.

Animals↗