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Biomedical subjects

H M Chen

Publications and source records attributed to H M Chen.

At least 163 records · Page 9Linked to original sources
PubMed1987

Immunohistochemical studies of colorectal carcinoma with a monoclonal antibody against carcinoembryonic antigen.

Immunoperoxidase localization of carcinoembryonic antigen (CEA) was performed on tissue sections of colorectal carcinoma using a monoclonal antibody (MAb) against CEA. CEA has been demonstrated in 20 out of 22 rectum carcinomas (90.9%), in all of 23 colonic carcinomas, in none of 4 hyperplastic polyps and in 2 out of 6 adenomatous polyps (33.3%). CEA was found more often, and the intensity of the staining was stronger in well-differentiated carcinomas than in moderately and poorly differentiated carcinomas. No correlation was found between the presence of CEA in colorectal carcinoma and the stages of the disease. The mean values of serum CEA in patients with colorectal carcinoma and polyps with negative, weakly and strongly positive staining were 5.4 +/- 3.9 ng/ml, 28.3 +/- 23.8 ng/ml and 99.8 +/- 145.3 ng/ml respectively. Elevation of serum CEA occurred in 30 out of 39 (78.9%) cases with strongly positive CEA staining, in 4 out of 6 (66.7%) with weakly positive and in 1 out 9 (11.1%) with negative staining. A significant difference was found in serum CEA activity between the group with negative CEA staining and positive CEA staining (P less than 0.01). Our results suggest that the monoclonal antibody (MAb C27) can be used for the localization of CEA in conventionally prepared tissues of colorectal carcinomas by immunoperoxidase techniques for routine immunopathological diagnosis.

Adenocarcinoma↗
PubMed1987

Serological survey of immune response to tetanus toxoid using antitoxin enzyme immunoassay.

A method for testing serum tetanus immunoglobulin (TIG) was set up using enzyme immunoassay kit (EIA kit) and prepared by competitive principle in this laboratory. Forty-eight human sera tested by both EIA and toxin neutralization test (NT) in mice were in good agreement. Determination coefficient (r2) of the EIA and NT was 0.922. The lowest detectable dose was 0.1 IU/mL ELISA value. Many authors believe this ELISA value to be a safe protection TIG level. For serological survey of immune response to tetanus toxoid, sera from two groups of subjects were examined. Among 83 subjects, each over 40 years of age, only 47.0% were positive to TIG EIA level. Forty-six subjects with undetectable EIA titres to tetanus toxoid (TT) were immunized against two doses of TT at an interval of four weeks; 44 (95.6%) demonstrated TIG concentration of greater than or equal to 0.2 IU/mL within two weeks to one month following the last dose vaccination. The TIG positive rates of 725 school students' sera, selected by multistage sampling from 2395 specimens, were reported. Those were collected by simple random sampling from geographical area in the North, South, Central, Central Mountain, and East areas of Taiwan according to age groups. They were 80.8%, 65.1%, 56.0%, and 42.0% to the age groups of 0-4, 5-9, 10-14, and 15-17 years respectively. The probabilities of each near by two groups were p less than 0.1; p less than 0.05; p less than 0.05. The differences of positive rates in the last three groups were significant.

Adolescent↗
PubMed1987

Decompression and occurrence of cataract in enucleated eyes of experimental animals.

Chamber flight at a simulated altitude of 58,000 ft (17,680 m) or more caused marked lens opacities in enucleated eyes of the experimental animals. After descent to ground level, the opacity could subsequently be regressed despite complete deprivation of blood supply to the eye. The present finding suggests that decompression might play an important role in inducing such a cataract.

Animals↗
PubMed1985

[Clinical evaluation of a domestically prepared enzyme immunoassay kit for the detection of hepatitis B surface antigen].

National Institute of Preventive Medicine (NIPM) has succeeded in the development of an enzyme immunoassay (EIA) kit for detection of hepatitis B surface antigen. The sandwich principle was used for the test. Guinea pig anti-HBs IgG was used for coating microtiter plates and Horseradish peroxidase was conjugated with goat specific anti-HBs. Its stability is longer than 4 months. The lowest detectable dose is 0.7 ng/ml or better for subtype ad of HBsAg tested with Hepatitis Sensitivity Panel, Bureau of Drug and Food, Department of Health. The regression curve was determined by testing 66 samples with Auszyme II (EIA Kit. Abbott Lab.) and NIPM Kit, while Auszyme II used as a reference kit. The two EIA kits correlated well with a coefficient of determination (r2) of 0.86. Evaluation on 1,157 patients' and officers' serum samples in Tri-Service General Hospital showed that the positive rate was 24.7% (286/1,157) by RIA (Clinical Assays, Travenol Lab., USA) and that of NIPM EIA Kit was 24.4% (282/1,157). There was no statistical significance in terms of positive rate (p greater than 0.05). The positive rates of 534 blood donors are 22.1% (118/534) and 21.9% (117/534) respectively. Another evaluation on 974 serum samples in National Taiwan University Hospital showed that the positive rate was 27.2% (265/974) by Ausria II-125 (RIA. Abbott Lab.) and that of NIPM EIA Kit was 27.4% (267/974). The undetectable rate and false positive rate of NIPM EIA Kit were 0.41% (4/974) and 0.62% (6/974) respectively. In comparison with four other kind of commercial EIA Kits, the results of NIPM EIA Kit were satisfactory also. We have scaled up the reagent preparations for the kit, except the antibody coated microtiter plate preparation. At the end of March 1985 we will supply 850 EIA kits for the Development Center for Biotechnology for their hepatitis B vaccine production program.

Hepatitis B Surface Antigens↗
PubMed1984

Bubble formation of aqueous humor and lens opacity during chamber flight.

A transparent miniature decompression chamber was placed on the stage of a large-working zoom-stereo microscope so that the effect of decompression on the frog eye could be microscopically observed and photographed. It was found that chamber flight at a simulated altitude of 66,000 ft (20,117 m) or more caused bubble formation in aqueous humor and lens opacities in some of the experimental animals. On return to ground level, the bubbles either decreased in size or completely disappeared. The cataract could also regress after recompression to 1 atm. Such lens opacities may be termed altitude cataract, instead of asphyxial or anoxic cataract.

Aerospace Medicine↗
PubMed1983

Aspirin-sulfinpyrazone in prophylaxis of deep venous thrombosis in total hip replacement.

In postoperative hip arthroplasty patients, treatment with aspirin and sulfinpyrazone resulted in a statistically significant reduction of venographically diagnosed thrombi in the proximal veins of the leg. This reduction was most apparent in thrombi that involved the iliac vein. When compared with their placebo-treated counterparts, female patients who received the active treatment experienced a statistically significant 75% reduction of thrombosis, compared with a 32% reduction for men that was not statistically significant. There were no serious adverse effects. Factors were identified that may influence the result of drug prophylaxis trials in deep-vein thrombosis.

Adult↗
PubMed1981

Cytomegalovirus infection of the uterine cervix: local cervical infection and antibody response.

Thirty-three women were examined on three or more occasions, each at 2-month intervals. The overall recovery rate of cytomegalovirus (CMV) was 28% (60/215). CMV was recovered from 53% of the cases where the local antibody was 1 : 64 or greater but the greatest difference occurred below titers of 1 : 32. Below that level virus was recovered in less than 5%, compared to a prevalence of 35% for cases with a titer of 1 : 32 (P less than 0.001). Twenty-eight cases in whom CMV was sought underwent colposcopy examination and had cytologic smears examined by the papanicolaou method. The external uterine cervix with columnar cells only yield a CMV prevalence of 3/17 (18%). However, if colposcopy showed either atypical transformation or metaplasia the prevalence was 4/11 (36%). Similarly, it is provocative that the prevalence of CMV appears to increase with abnormal cytologic findings to 33% recovery in severe dysplasia or carcinoma in situ.

Antibodies, Viral↗
PubMed1979

The limited utility of fibrinogen I 125 leg scanning.

Using venography as the reference procedure, this study examined the utility of fibrinogen I 125 scanning for the detection or demonstration of deep venous thrombosis. The results demonstrate the inability of leg scanning to detect accurately the presence or absence of thrombi in the deep venous system. Most striking was the lack of sensitivity of this procedure in areas where the propensity for embolization is greatest. Sensitivity is extremely low in the anatomic areas where leg scanning demonstrates reasonable specificity. The results are nearly identical in the extremity not operated upon. The validity of all prior studies relying heavily or exclusively on 125I leg scans to determine the presence or absence of thrombi must be critically reassessed.

Fibrinogen↗
PubMedDate not supplied

Delta infection in asymptomatic carriers of hepatitis B surface antigen: low prevalence of delta activity and effective suppression of hepatitis B virus replication.

We examined the prevalence of serum anti-delta antibody among 769 intravenous drug abusers in Taiwan. delta infection was found extremely common in the HBsAg-positive carriers with drug abuse, because 128 (85%) of 151 carriers were positive for anti-delta. However, most of antibody titers were low (less than 1:5,000). By molecular hybridization, delta RNA genomes were detectable in only five (4%) of 128 asymptomatic carriers positive for anti-delta. The results suggested that most of them had previous, instead of ongoing, delta infection. We also studied the serum markers reflecting hepatitis B virus replication in these carriers and a control group. Hepatitis B e antigen was positive in only 12 (10%) of 115 anti-delta positive carriers in contrast to 22 (23%) of 95 age- and sex-matched HBsAg-positive, anti-delta negative volunteers donating blood (p less than 0.025). Furthermore, in contrast to the close association between HBeAg and hepatitis B virus DNA generally present in HBsAg carriers (concordance in this series: 79%), among the 12 HBeAg-positive subjects of the delta infected group, only two, or 17%, had serum hepatitis B virus DNA (p less than 0.003). Such suppressing effects did not require a simultaneous presence of the delta agent, as shown by the lack of delta RNA genomes in the serum by sensitive assay. We conclude that although delta superinfection is common in the asymptomatic HBsAg carriers with intravenous drug abuse in the nonendemic area of Taiwan, continuous delta activities are uncommon in them. In addition, the previous delta infection probably exerts effective suppression on the hepatitis B virus replication in these HBsAg carriers.

Adult↗
PubMedDate not supplied

Quantifying ethanol by high performance liquid chromatography with precolumn enzymatic conversion and derivatization with fluorimetric detection.

We quantified ethanol by measurement of the subsequent increase in acetaldehyde after reaction with alcohol dehydrogenase and nicotinamide adenine dinucleotide (ADH-NAD) with a fluorimetric HPLC method. Ethanol standards ranging from 0.3 to 200 mg/dl were investigated and the limit of quantitation of the fluorimetric HPLC method was found to be 6 mg/dl. The accuracy of the HPLC method was assessed by assaying blood samples containing 6-200 mg/dl of ethanol and comparing its results to those of the ADH-NAD enzymatic method (r2 = 0.993). The coefficients of variation for intraassay (assayed ten times) and interassay (assayed on 7 consecutive days) were 6.7% and 9.3% for blood samples containing 50 mg/dl of ethanol and 4.0% and 17.9% for blood samples containing 200 mg/dl of ethanol. The blood ethanol concentrations of a volunteer after a pulse of 0.3 g/kg of ethanol determined with the described HPLC method were correlated to the results from the ADH-NAD enzymatic method (r2 = 0.986). In conclusion, the fluorimetric HPLC method for measurement of ethanol here described is of potential clinical utility.

Alcohol Dehydrogenase↗
PubMedDate not supplied

A reusable and specific protein A-coated piezoelectric biosensor for flow injection immunoassay.

A hydrophilic matrix of periodate-oxidized dextran was used as a double-sided linker to covalently immobilize Staphylococcus aureus protein A (SpA) molecules onto a poly-L-lysine-modified piezoelectric crystal surface to improve their stability, activity, and binding specificity with human immunoglobulin G (IgG) in flow injection assays. The prepared sensing crystals displayed best sensitivity and reusability at a flow rate of 140 microL/min. A human IgG concentration as low as 0.3 nM can be detected by this system. Up to 19 successive assay repetitions were achieved without significant loss of sensitivity using the same crystal. The analysis of adsorption kinetics indicates that such a preparation can greatly increase the amount of available active human IgG binding sites on immobilized SpA. Hardly any response arising from unspecific binding was detected. In addition, the sensing crystal prepared by this method was found to retain activity better than one prepared via direct deposition when stored in either wet or dry states. Finally, the prepared SpA-coated crystals were applied to the affinity immobilization of polyclonal goat anti-Schistosoma japonicum glutathione-S-transferase (GST) and were able to subsequently detect GST and its genetically engineered mutant either in a purified form or in the crude cell lysate.

Animals↗
PubMedDate not supplied

Use of alternative therapy among pediatric oncology patients in Taiwan.

Both alternative medicine and western medicine have been commonly used to treat pediatric cancer patients in Taiwan. Each has its own intrinsic strengths and weaknesses and they can be complementary. Little is known about medical help-seeking behaviors of parents of pediatric cancer patients, especially those related to alternative therapies. This study investigated the extent and parental expectations on use of alternative therapies. All primary caregivers of 63 eligible patients were interviewed. Use of alternative therapies, regardless of education level or social status of their families, is prevalent (n = 46, 73%) in Taiwan. Commonly used alternative therapies included, in order of popularity, formulated functional food (n = 22, 48%), temple worship/shamanism (n = 19, 40%), traditional Chinese medicine (n = 9, 20%), secret recipes/herbs (n = 13, 28%), and diet supplements (n = 9, 19%). Such practices generally occur without medical guidance from oncologists, largely because of poor interactions between parents and oncologists. Future efforts should be made to encourage both parents and oncologists to discuss this issue. Nurses may serve as mediators by developing mutual trust and a sharing relationship between these groups.

Adolescent↗
PubMedDate not supplied

High efficiency magnetic bearing for a rotary blood pump.

Mohawk Innovative Technology, Inc. (MiTi; Albany, NY) and the Cleveland Clinic Foundation (Cleveland, OH) have been engaged in a joint project to develop a new, high efficiency magnetic bearing for use in a rotary blood pump. Such a bearing would have some advantages with respect to permitting large, low shear clearances and avoiding crevice-like pivot interfaces and surface wear related issues. While magnetically suspended blood pumps have been demonstrated, other prototypes reported in the literature consume 5-15 W of power to energize the bearing. The MiTi bearing has been prototyped and tested. The design is a hybrid configuration, radially passive and axially active. The rotor-and-bearing system has been run in air and in blood analog solution, in all orientations. Measurements show a bearing power consumption below 0.5 W. Vibration peaked at 0.2 g in blood analog solution; frequency analysis indicated that this was primarily related to motor design features. Measured displacements from the equilibrium position were less than 0.005 cm. Based on this highly successful bearing prototype, an integrated pump/bearing system is now being developed.

Heart-Assist Devices↗
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↗