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Biomedical subjects

M Y Chou

Publications and source records attributed to M Y Chou.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Survey on oral hygiene status in children with Down's syndrome and mental retardation].

The purpose of this study was to compare the periodontal condition of children with Down's syndrome and other types of mental retardation with normal children. We used two indexes: a plaque index and a gingival index. By means of the student t-test and ANOVA statistical procedure, we found the following. Mentally retarded children had a higher average intelligence than children with Down's syndrome, and significant differences existed among the three groups on both the plaque index and the gingival index, while sex had no influence on these results.

Analysis of Variance↗
PubMed1991

The eosinophil as a cellular source of transforming growth factor alpha in healing cutaneous wounds.

Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) are known to promote the healing of epithelial wounds. Eosinophils are present in healing wounds and have recently been shown to be capable of producing TGF-alpha. This investigation was done to determine if eosinophils infiltrated into healing wounds are capable of expressing this cytokine. Using the rabbit cutaneous open wound model, the study found that the eosinophil is one of the predominant cell types in the healing wound, beginning from the seventh day and thereafter. Most surprisingly, the majority of the eosinophils present in the healing wound were found to contain TGF-alpha mRNA and protein by in situ hybridization and immunohistochemistry. Thus it is proposed that the delivery of TGF-alpha by eosinophils to epithelial wound healing sites represents a normal body mechanism whereby this multifunctional cytokine can accelerate the wound healing process.

Animals↗
PubMed1990

Shrimp hepatopancreatic deoxyribonuclease--purification and characterization as well as comparison with bovine pancreatic deoxyribonuclease.

Deoxyribonuclease (DNase), isolated from shrimp hepatopancreas by chromatography on DEAE-cellulose, Sephadex G-100, phenyl-Sepharose and hydroxyapatite, is homogeneous as shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The metal ion requirements and the pH-activity optima of shrimp DNase are very similar to those of bovine DNase. Both shrimp and bovine DNases are sensitive to iodoacetate inactivation under the same condition. The active shrimp DNase molecule is a monomer of Mr 44,000, approx. 13,000 larger than the Mr of bovine DNase. Shrimp DNase is rich in glutamic acid, glycine and half-cystine. The single polypeptide chain of shrimp DNase is highly cross-linked by 18 disulfides as compared to only two disulfides in bovine DNase. In contrast to bovine DNase, shrimp DNase is not a glycoprotein, is devoid of the activity against p-nitrophenyl phenylphosphonate (a synthetic substrate for bovine DNase), and resists to inactivation by beta-mercaptoethanol or trypsin under the Ca2(+)-free condition at pH 8. Shrimp DNase shows an isoelectric point of 4.06 on the thin-layer isoelectric focusing and rapidly loses its activity at pH below 5.

Amino Acids↗
PubMed1990

Human eosinophils express transforming growth factor alpha.

Transforming growth factor alpha (TGF-alpha) is a pleuripotential cytokine with diverse biological effects, including the ability to influence the proliferation of normal cells or neoplastic epithelial cells. Eosinophils are a subset of granulocytes that normally enter the peripheral tissues, particularly those beneath gastrointestinal, respiratory, and urogenital epithelium, where they reside in close proximity to the epithelial elements. In this study, we demonstrate that the great majority of eosinophils infiltrating the interstitial tissues adjacent to two colonic adenocarcinomas and two oral squamous cell carcinomas labeled specifically by in situ hybridization with a 35S-riboprobe for human TGF-alpha (hTGF-alpha). No other identifiable leukocytes in these lesions contained detectable hTGF-alpha mRNA. We also examined leukocytes purified from a patient with the idiopathic hypereosinophilic syndrome. 80% of these eosinophils, but none of the patient's neutrophils or mononuclear cells, were positive for hTGF-alpha mRNA by in situ hybridization, and 55% of these eosinophils were positive by immunohistochemistry with a monoclonal antibody directed against the COOH terminus of the mature hTGF-alpha peptide. Finally, the identification of the purified eosinophil-associated transcript as hTGF-alpha was confirmed by polymerase chain reaction product restriction enzyme analysis followed by Southern blot hybridization. In contrast to eosinophils from the patient with hypereosinophilic syndrome, the peripheral blood eosinophils from only two of seven normal donors had detectable TGF-alpha mRNA and none of these eosinophils contained immunohistochemically detectable TGF-alpha product. Taken together, these findings establish that human eosinophils can express TGF-alpha, but suggest that the expression of TGF-alpha by eosinophils may be under microenvironmental regulation. Demonstration of TGF-alpha production by tissue-infiltrating eosinophils and the eosinophils in the hypereosinophilic syndrome identifies a novel mechanism by which eosinophils might contribute to physiological, immunological, and pathological responses.

Adenocarcinoma↗
PubMed1990

Use of intracellular H3 messenger RNA as a marker to determine the proliferation pattern of normal and 7,12-dimethylbenz[a]anthracene-transformed hamster oral epithelium.

One of the major goals in cancer research and diagnosis is to identify in a tissue the population of actively dividing cells and their pattern of growth and to differentiate the proliferation patterns of normal and transformed tissues. We now describe a method for determining the proliferation pattern of any tissue (normal, diseased, or transformed), applicable in any mammalian species. This method is based on the fact that the transcription of histone H3 gene in mammalian cells is tightly coupled to DNA synthesis during cellular division. Resting cells or cells that just exited the cell cycle will have no detectable H3 mRNA. The presence of H3 mRNA in a cell is thus a good indicator of its proliferation status. We carried out in situ hybridization of H3 mRNA in hamster oral epithelia exhibiting a variety of altered growth patterns as a consequence of exposure to the chemical carcinogen, 7,12-dimethylbenz[a]anthracene to demonstrate the usefulness of this technique. This application does not require in vitro manipulation of tissues nor does it require the prior administration of a tracer. The proliferation pattern at a single moment in time instead of an accumulated pattern over a period of time is produced. Finally, since the technique of in situ hybridization can be applied to archival tissues, retrospective studies can be done. This application should find usefulness in a wide variety of experimental research settings, particularly cancer research.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

Production of transforming growth factor alpha by hamster eosinophils.

Previously it was demonstrated that malignant transformation of the Syrian hamster cheek pouch mucosa is associated with the expression of TGF-alpha. Therefore in situ hybridization and immunohistochemistry was used to investigate the cellular sources of TGF-alpha production in this model system. Surprisingly one cell type in the inflammatory infiltrate present in the connective tissue adjacent to the transformed epithelium represented a major source of TGF-alpha mRNA. Detailed analysis of these cells revealed that they were eosinophils. In addition to TGF-alpha mRNA, about 40% of the eosinophils associated with the oral tumors exhibited TGF-alpha product reactive with a monoclonal antibody against the C terminus of the mature TGF-alpha peptide. Normal hamster bone marrow eosinophils also exhibited TGF-alpha mRNA and product by in situ hybridization and immunohistochemistry. These results suggest that the eosinophil represents a biologically significant source of TGF-alpha.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

[Investigation on the relation between hepatitis B virus knowledge and needle-stick injury of hospital personnel].

The purposes of this study are: (1) to understand the knowledge of Hepatitis B virus known by hospital personnel. (2) to investigate the injury caused by accidental needle stick and its frequency. (3) to identify those personnel and job activities at high risk of needlestick injuries, to assess current medical management of these injuries in our hospital, and also to develop rational guidelines for prevention, based on the findings. 510 effective questionnaires were collected and analyzed by SPSS analytical system. The result of the present study showed that 77.1% hospital personnel had been experienced by needlestick injury. Most injuries occurred during recapping the needle after use and disposal of used needle. 92.7% hospital personnel felt that hospital should provide all the expense needed for Hepatitis B virus immunoglobulin while needle-stick injuries happened within the hospital. 86.3% of them felt that hospital should establish a special committee to evaluate and manage all the needle-stick injuries events. This study also showed that hospital personnel who have been working less than five years and their age between 21-30 can pay more attention to this kind of event. Dietitian and doctor got higher score in this study. Hospital personnel who were infected by Hepatitis B virus scored higher than uninfected one. In conclusion, we recommend not recapping used needles and making widely available and promoting use of an efficient needle disposal system. And we hope that those who have never been infected by Hepatitis B virus should accept vaccination as soon as possible.

Accident Prevention↗
PubMed1990

A rapid method to determine proliferation patterns of normal and malignant tissues by H3 mRNA in situ hybridization.

A general method applicable for the determination of any mammalian tissue's proliferative pattern is described. This method determines the cellular mRNA level of a proliferation-dependent gene, histone H3, by in situ hybridization. The cell-cycle S-phase-specific expression of this highly conserved ubiquitous cellular gene, and the lack of it in resting cells, permits the unambiguous identification of cycling cells in any tissues, normal or diseased. This method can be conveniently coupled with routine biopsy and could be streamlined for a central laboratory with results obtainable in 2 days. Furthermore, this procedure works successfully on formalin-fixed paraffin-embedded sections, thus allowing retrospective studies of biopsies or autopsy materials.

Cell Cycle↗
PubMed1989

Detection of transforming growth factor-alpha messenger RNA in normal and chemically transformed hamster oral epithelium by in situ hybridization.

We have recently demonstrated the consistent detection of transforming growth factor alpha (TGF-alpha) in chemically transformed hamster oral tumors. By Northern blot analysis, no TGF-alpha mRNA can be detected in normal cheek pouch mucosa. The consistent expression of TGF-alpha associated with the malignant transformation in the well-defined hamster oral cancer model prompted us to hypothesize that the aberrant expression of this important cellular gene could be related to a specific stage of epithelial alteration. In situ hybridization was used to test this hypothesis. We now report that by in situ hybridization we can detect TGF-alpha mRNA in normal hamster oral epithelium and also at all stages of transformation. In all epithelium, labeling of TGF-alpha mRNA in the basal layer is more pronounced than that observed in the spinous and squamous layers. There is a significant increase of TGF-alpha mRNA labeling early in 7,12-dimethylbenz(a)anathracene-induced oral carcinogenesis. This increase is associated with morphological changes of epithelial hyperplasia or dysplasia. Although lesions exhibiting full-thickness epithelial dysplasia (carcinoma in situ) showed more labeling of TGF-alpha mRNA than do areas of lesser dysplasia, the transition to full-fledged papillary or invasive squamous cell carcinoma is not associated with further elevations of TGF-alpha expression.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

Inhibition of growth and development of the transplantable C-6 glioma cells inoculated in rats by retinoids and carotenoids.

Experimental data were provided to demonstrate the inhibitory effects of retinoids (retinal, retinoic acid, retinyl acetate and retinyl palmitate) and carotenoids (beta-carotene, lycopene and crocetin) on the growth and development of the C-6 glioma cells inoculated in rats. In the pretreatment experiments, most of these compounds could prolong the latency period of T50 (time for 50% tumor incidence). At week 7, the growth inhibition was 57-67% (P less than 0.02) with carotenoids and 40-55% (P less than 0.05) with retinoids. In the post-treatment experiments, the growth inhibition was 30-55% (P less than 0.05) with carotenoids and 21-42% (P less than 0.05) with retinoids. No significant hepatotoxic effect was observed in all treated groups as indicated by the constant levels of serum enzymes (e.g. aspartate amino-transferase, alanine amino-transferase and alkaline phosphatase) and bilirubin. The mechanisms of tumor inhibition through the enhancement of anti-tumor immunity by both carotenoids and retinoids were discussed.

Animals↗
PubMed1989

Opsonophagocytosis of Staphylococcus aureus by diabetics' sera and monocytes.

The ingestion and the intracellular killing of Staphylococcus aureus by monocytes from patients with noninsulin-dependent diabetes mellitus (NIDDM) under good control (mean 2-h postprandial blood glucose less than 150 mg/dl in the past 6 months) or under poor control (mean 2-h postprandial blood glucose greater than 200 mg/dl in the past 6 months) were investigated. The ingestion was expressed as a phagocytic index which was a percentage of the total bacteria added in the reaction mixtures, while the intracellular killing was expressed as the percentage of ingested bacteria which were destroyed. The phagocytic index (mean +/- S.E.) of healthy subjects (HS), diabetics under good control (DGC) and diabetics under poor control (DPC) were 45.1 +/- 3.5, 38.2 +/- 2.2, and 32.1 +/- 3.4%, respectively. This showed that monocytes from diabetics ingested S. aureus more poorly than did those from HS (p less than 0.001) and monocytes from DPC ingested more poorly than did those from DGC (p less than 0.001). There was no difference in intracellular killing between HS and DGC, but a marked difference was noted between DGC and DPC. Specific antibodies (IgG) as demonstrated by indirect immunofluorescence assay had little effect on ingestion but could enhance complement activation and then increase ingestion whether the serum was from HS, DGC, or DPC. On the other hand, the significant effect of complement activity in the presence of specific antibodies on intracellular killing was only observed on HS and DGC, suggesting that antibody-dependent complement activation could be a crucial mechanism for efficient intracellular killing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

A cytogenetic study of mentally retarded school children in Taiwan with special reference to the fragile X chromosome.

A cytogenetic study was made on 341 mentally retarded children in the Provincial Nantou Rehabilitation Center for the Mentally Retarded and the St. Raphael Opportunity Center in Tainan. Of the 89 mentally retarded children with chromosomal abnormalities, 63 had Down syndrome, 13 had the fragile X [fra(X)] syndrome, and the remaining had other aneuploid constitutions. Family studies were possible for 2 of the 13 fra(X) probands. The results of this study illustrate the contribution of chromosomal abnormalities to the pathogenesis of mental retardation in children.

Chromosome Banding↗
PubMed1988

Outbreak of acute hemorrhagic conjunctivitis due to coxsackie A24 variant--Taiwan.

Outbreaks of acute hemorrhagic conjunctivitis caused by enterovirus 70 and several serotypes of adenovirus have occurred in Taiwan since 1971. In 1980-1981, there was a pandemic of acute hemorrhagic conjunctivitis in southeast Asia caused by coxsackie A24 variant (CA24v); however, this virus did not affect Taiwan. In October 1985, CA24v was isolated for the first time from patients with acute hemorrhagic conjunctivitis in southern Taiwan. The following summer, a large epidemic of acute hemorrhagic conjunctivitis due to CA24v occurred. An epidemiologic investigation of patients seen at one ophthalmology clinic in Taipei City revealed that school-age children were the most likely group to introduce illness into households (p less than 0.001) and that males were more often household index cases than were females (p less than 0.01). Multiple case households tended to be more crowded (3.0 vs. 2.5 persons per bathroom; p less than 0.05) and had illness introduced by younger family members (median age of index case = 10 vs. 17 years; p less than 0.01). It is unknown whether this outbreak is an isolated occurrence or represents another resurgence of CA24v in the area.

Adolescent↗
PubMed1987

An autopsy-proved case of AIDS in Taiwan.

The first case of AIDS positively identified in a non-foreigner in Taiwan was a 25-year-old unmarried male who had practiced homosexuality for ten years. The patient began to have abdominal pain accompanied with loose stools and weight loss in June 1985, followed by fever, cough, headache, dizziness, and loss of memory. Facial hyperpigmentation and extensive oroesophageal candidiasis were noted. Laboratory studies showed severe lymphopenia with a reversed T-helper to T-suppressor ratio, cutaneous anergy and polyclonal gammopathy. Human immunodeficiency virus (HIV) antibodies were positive by ELISA and Western blot, and the virus was isolated from the blood. At autopsy, disseminated cytomegalovirus infection, extensive CNS toxoplasmosis and early lesions of Kaposi's sarcoma were demonstrated. The detection of HIV in the adrenal medulla supports the consensus that the virus is neurotropic.

Acquired Immunodeficiency Syndrome↗